Foredrag

The impacts of climatic changes on nature and socioeconomic impacts of climate change: an awkward relationship.

Asbjørn Aaheim

This presentation questions the observed trend of bringing studies of social and economic impacts of climate change closer to the knowledge about physical changes in the natural environment by narrowing the scope and focus. It is pointed out that the advantage of delimiting the focus for the purpose of utilising the best available knowledge about the physical changes usually has a cost in terms of neglecting vital socioeconomic relationships. With examples from impacts assessments of climate change it is shown that there is no one-to-one relationship between physical changes and socioeconomic impacts. It is emphasised that there is a need for a framework to systematically organising data and characterising impacts of climate change in order to prepare them for socioeconomic analysis. It is suggested to transform results about impacts into the framework of national accounting. The advantages are, firstly, that results from independent impacts studies are made comparable, and the contribution from each of them can be analysed in a broader socioeconomic context. Second, it provides a checkpoint for the availability of data about impacts on the national scale, and a reference for an evaluation of the data quality. Third, putting impacts assessments into the frames of traditional economic analysis enables evaluation of climate change in familiar terms, such as GDP, and analysis of impacts with established analytical tools.

Local planning and climate change adaptation

Dr Carlo Aall, Western Norway Research Institute (WNRI), P.P. Box 163, 6851 Sogndal.

caa@vestforsk.no / www.vestforsk.no My presentation is based on research within three research fields: More then 15 years of research on local environmental policy in general; a 3 year project on evaluating local energy and climate planning processes (financed by the Norwegian Research Board programme SAMSTEMT) and the project ”Climate Change in Norway: An Analysis of Economic and Social Impacts and Adaptations” in cooperation between CICERO/UiO, ProSus/UiO, SNF (Bergen) and WNRI (financed by the research fund). The latter included four studies conducted by WNRI: Studies on the effects of climate change on tourism, a report identifying institutions central in climate change adaptation at the local level of governance, a report suggesting a system of local climate vulnerability indicators, and studies of how local institutions responded to experiences gained from the New Years Eve hurricane of 1992.

Even if we assume that there is a reasonable degree of certainty with regard to the question of whether or not climate changes actually are taking place, and furthermore, that man-made emissions of climate gases are an important causal factor, climate change adaptation will always be strongly linked to the issue of uncertainty. Any kind of local climate policy will have to deal with two types of basic uncertainty: the scientific uncertainty regarding the local variations of climate changes, and the political uncertainty regarding the absence or presence

of national climate policies. In sum, this gives us a basis for arguing that local climate policy in practice should be based on the precautionary principle.

It is not obvious how the precautionary principle should be applied in practice. One possible approach is to point to the precautionary principle in an argument for public planning as a crucial instrument with regard to both reduced emissions and climate change adaptation. In a Norwegian context this implies that the local level of governance must have a central role to play. Municipal planning is mandatory according to the planning and building act. Municipalities also have a long standing tradition in planning with high relevance for both climate mitigation and adaptation policies; that is local energy planning, transport and land use planning, environmental policy planning, greenhouse gas mitigation planning and civil defence planning.

An important tool in local planning is the use of indicators. Indicators could also be of vital use in local planning processes dealing with assessing local vulnerability towards climate change. The purpose of developing vulnerability indicators is to give a more operational basis for making risk and vulnerability assessments. We have distinguished between a top-down and a bottom-up approach. The first approach means that we use available national statistics and results from down-scaling of global climate models to make a first rough ranking of the total vulnerability for Norwegian municipalities. Here we use a limited number of regional indicators. The second approach entails the use of a number of supplementary local indicators based on the collection of local data to make more detailed assessments in the supposedly most vulnerable municipalities.

Ecosystem process modeling with input data from climate scenarios, preliminary experiences.

Lars Bakken

GCM simulations of the present and future global climate can be downscaled to provide local “weather forecasts”. Such downscaled global warming scenarios are like manna from heaven for ecosystem process modellers because they allow us to explore the effects of future global warming on ecosystem functions, including their feedback on the global warming. These phenomena are not predictable by simple statistical climate information (average temperature, annual precipitation etc), because of various non linear responses of interacting components within the ecosystems. We need real weather scenarios (daily weather information) to run our models! The Norwegian research program Regclim has produced such regionalized weather scenarios for the period 2030-2049, based on the basic global scenario from Max-Planck-Institute (MPI) in Germany.

We have used these “weather forecasts” for 2030-49 (SIM3049) as driving data in a cluster of physical, biological, and economical models for agroecosystems. Such exercises necessarily requires an investigation of validity of the weather forecasts as well as our ecosystem forecasts. As a control, we used downscaled MPI simulations for the period 1980-99 (SIM8099), which were compared to observed weather in the same period (OBS8099). Some problematic characteristics of the SIM8099-weather were identified, which had severe consequences for the simulation of water transport, plant growth and soil erosion. Some of

these problems were solved by adjustments based on empirical downscaling, and the RegClim project plans for further improvements in the near future. Other problems experienced were the lack of transparency and a large annual variability (20 years scenarios are too short to test relevant changes).

Assuming that the contrast between SIM3049 and SIM8099 is an adequate prediction of the climate change in response to future global warming, we find that soil erosion will increase dramatically and nitrate leaching may increase substantially. The latter is a result of an altered economic optimum for N-fertilization due to slight changes in the product functions. This was not statistically significant, however.

Ecological and nutrient feedbacks to anthropogenic ocean acidification from rising atmospheric CO2

Richard Bellerby – Bjerknes Centre for Climate Research, University of Bergen

The surface oceans are increasing in carbon dioxide, in concert with rising atmospheric

concentrations, and there is a consequentially reduction in the seawater pH. Models show that

within this century, the anticipated drop in pH will reach levels not seen for the last 420,000

years. Laboratory and field studies have shown that such pH levels have a considerable effect

on plankton physiology and community structure. Further into the next century ocean pH will

reduce to levels that severely effect the survival of certain marine organisms, particularly

benthic and polar species. Decreased pH results in changes in nutrient utilisation and export

production which will have consequences for food web structure and ultimately for fisheries.

Such planktonic biogeochemical responses will have pronounced feedback to atmospheric

carbon dioxide concentrations.

Fører klimaendring til at fjellreven forsvinner?

Nina E. Eide, John D.C. Linnell, Unni S. Lande, Vidar Grøtan, Olav Strand og Pål Prestrud

Arctic fox populations declined rapidly around 1900 throughout Fennoscandia and were close to extinction around the 1920s. Despite more than 70 years of protection there has been no recovery of the arctic foxes. The decline was extremely pronounced in Fennoscandia. Although less pronounced, the decline in arctic foxes was observed throughout the whole Arctic. The changes in population sizes across several continents happen approximately at the same time; around 1900, implying a common change happening at larger spatial scales. Many hypotheses have been put forward to explain the non-recovery of the arctic fox; one of them is indirect effects of a warmer climate. The southerly (and lower altitudinal) distribution of

arctic foxes is probably constrained by the distribution of the dominant competitor, the red fox, with arctic foxes only surviving in areas that have too low productivity for red fox to survive. At the same time as arctic foxes declined, there was a general temperature rise from 1900 over the whole northern hemisphere. A general temperature rise is expected to result in a vertical rise in productivity zones; which also lead to the expectation that red fox distribution will expand vertically, leading to a decrease in potential arctic fox habitat. The main objective of this study has been to improve our understanding of possible influences of climate changes on community structure in alpine ecosystems, with main focus on the relationship between the arctic fox (a “polar” species) and the red fox (a “temperate” species). Changes at the level of species could in the long run lead to changes in species diversity, shorter food chains and a simplification of alpine ecosystems. The red fox as a typical generalist predator is also a pronounced keystone species, and an increase and expansion of the red fox population could hence have large influence on both the structure and the dynamic of the alpine ecosystem. We explore coincident changes in the abundance of species having the same specialist food niche as the arctic fox; snowy owl, rough-legged buzzard, long-tailed skua; which could indicate larger changes in the structure of alpine ecosystems, and if these changes relate to the climatic changes that have occurred over the last 100-150 years. Could further climate change result in loss of the arctic fox and typical alpine habitat niches?

RegClim: Local and regional climate scenarios for Norway: Evaluation of uncertainties

Eirik J. Førland, Rasmus Benestad, Inger Hanssen-Bauer & Torill E. Skaugen.Norwegian Meteorological Institute, P.O.Box 43 Blindern, N-0313 Oslo, Norway(e-mail: e.forland@met.no)

A survey of downscaled daily and monthly scenarios for Norway will be given, including both available and planned projections. Presently available downscaled scenario data from RegClim are available at: http://noserc.met.no/effect/. The presentation will focus on uncertainties of climate scenarios in our region evaluated by empirical downscaling of 17 global climate projections made for IPCC TAR.

Climate scenarios in general and local scenarios in particular are encumbered with several sources of uncertainty: a). Internal variations in the climate system leads to unpredictable natural variability. b). Uncertainties concerning future changes in climate forcings (Natural forcings, i.e. solar radiation, volcanoes, Anthropogenic release of gases and particles, Changes in land-use), c). Imperfect climate models (Imperfect knowledge about forcing and processes, Imperfect physical and numerical treatment of processes, Poor resolution in the global models) and d). Weaknesses in downscaling techniques.

Different AOGCM simulations may thus produce quite different regional climate scenarios, and examples will be given of spread in temperature and precipitation projections for Norway. Some of the pitfalls in deducing local projections from the spatial scale (55x55km) in the present RegClim Regional Climate Model (RCM) will also be discussed.

During phase 3 of RegClim, it will be established a RCM with finer spatial resolution, and methods for empirical downscaling of daily values will be improved. Special focus will be on developing methods for analysing risk of changes in frequency distributions and extreme

values of temperature, precipitation and wind. This is an important component for evaluations of societal and natural impacts of climate change. However, tailoring of climate scenarios for specific impact studies is not a part of the planned RegClim activities.

PAST CLIMATE OF THE NORWEGIAN REGION (NORPAST-2): STATUS & RESULTS

Morten Hald Project coordinator, Department of Geology, University of Tromsø

NORPAST-2 is a nationally coordinated NFR-project that aims to advance the knowledge of patterns and variability of past climate in the Norwegian Region (Norway and adjoining continental margin and fjords), and to contribute to the understanding of climate forcing factors. The studies focus on quantitative climate reconstructions during the last deglaciation, the Holocene and the Recent Past. We investigate a limited number of high-resolution sites from terrestrial and marine archives; by improving paleoclimatic proxies; and by synthesising existing and new data. The instrumental record of climate variability is too short and spatially incomplete to reveal the full range of seasonal to millennial-scale climate variability, or to provide empirical examples of how the climate system responds to large changes in climate forcing. This recent record is also a complex reflection of both natural and anthropogenic forcing (e.g., trace gases and aerosols). Various proxy sources, on the other hand, provide the much wider range of realisations needed to describe and understand the full range of natural climate system behaviour.

In this presentation I will give some examples from some new results form the first year of the project. This will include: 1) Climate variations over the last 1500 years; 2) Reconstructions of snow avalanche during the Holocene, Jostedalen inner Sogn; 3) Quantitative reconstructions of winter precipitation at Jostedalsbreen and Hardangerjøkulen during the Holocene; 4) Glacier variations during the Holocene; 5) Reconstructions of surface and bottom water temperatures along the Norwegian continental margin during the Holocene. 6) Age models for paleoclimatic proxy records. The reconstructions clearly show that climate in the Norwegian Region has been both significantly warmer and cooler that it is today during the Holocene. Both rapid (decadal) changes, as well as more gradual (century-millennial) changes have been observed during the past. Possible climate forcing mechanisms will be discussed.

Deep water ventilation processes

Peter M. Haugan, Tor Eldevik, Bjørn Ådlandsvik on behalf of the ProClim participants

The deep parts of the world oceans are ventilated from the surface in limited areas at high latitudes. Small scale ocean mixing processes, mesoscale variability, sea ice formation and salt release are involved in setting the properties of the deep water and the pathways of circulation between low and high latitudes. Since this circulation is crucial to the ocean heat transport, the surface temperature and the sea ice distribution, there is a need to understand the

physics of the processes and their sensitivity to atmospheric conditions. Studies in the Polar Ocean Climate Processes (ProClim) project focusses on process studies in the Storfjord area and the western Barents Sea, Norwegian Sea, and Greenland Sea.

The sea ice production and salt release in Storfjorden is primarily determined by the strength of northeasterly winds locally each winter. The resulting dense water volume and properties also depend upon the Arctic and Atlantic water masses advected into the area, i.e. on larger and longer time scale conditions. Mixing in the outflow is primarily determined by shear instability between the dense flow and ambient water above. This first order description based on measurements gives a good basis for modelling based on appropriate atmospheric forcing, although predictive capability for the whole system still remains to be tested.

Deep convection in the open ocean involves small net vertical volume flow but is nevertheless important for deep water properties and large scale pressure fields. The variability in the strength of the different ventilation processes and pathways on shelves and in the deep ocean is large. The possibility for alternation between different modes and shift between different areas in closing the overturning circulation will be addressed in later parts of the project but remains a motivation for the ongoing work.

CHEMCLIM: Tropospheric chemistry and climate

Ivar S.A. IsaksenDepartment of Geosciences, University of Oslo, P.O. Box 1022, Blindern, N-0315 Oslo. (ivar.isaksen@geo.uio.no)

In CHEMCLIM the overall focus is on how natural emission and emission of pollutants affect oxidation processes in the atmosphere and the distribution of chemical active greenhouse gases (e.g. ozone, methane), particles from natural (sea salt, mineral dust) and anthropogenic (e.g. sulfate, organics) sources, and how changes in the emission contribute to the global radiative forcing. Global model studies are being performed in three main areas: Studies of the oxidation potential of the troposphere and how it is changing due to changes in the emission of pollutants. The OsloCTM2 model has been updated with the newest and best emission inventories that are available. The purpose is to be able to make sensitivity studies of different emission source categories impact on current, past and future climate and pollution levels. The oxidation studies include particular model studies of ozone and sulfate particle formation due to ship emissions and studies of changes in sulfate burden due to emission changes over the last 10 to 15 years. Studies of sources of mineral dust and temporal changes in the global distribution have been performed in collaboration with University of California, Irvine. Studies of climate-chemistry interactions of water vapour in the upper troposphere and lower stratosphere (UTLS) region are being performed in collaboration with State University of New York (SUNY), Albany, using the NCAR CCM3 climate model. Most of the modeling studies in the CHEMCLIM project are performed by PhD students as part of their thesis work, and include a significant part of basic process studies and model development. The Oslo CTM2 has been developed to include extensive physical and chemical schemes to study chemical active gaseous and aerosol compounds. Comparisons with observations show that the models developed are able to realistically reproduce the distribution of major chemically active compounds in the troposphere. The modeling activities performed in CHEMCLIM are the basis for particle studies and ozone climate–chemistry studies performed in AerOzClim. Results from the modeling activities in the different areas will be presented.

CHEMCLIM: Studier av kjemisk active klimagasser (ozon, methan) og partikler (sulfat, organiske partikler, sjøsalt, mineralstøv) i atmosfæren og deres innvirkning på strålingen.

RegClim Phase III: A focus on risks and uncertainties in climate projections for Northern Europe and parts of the Arctic.

Trond IversenProject leader of RegClim, Department of Geosciences, University of Oslo, P.O. Box 1022, Blindern, N-0315 Oslo. (trond.iversen@geo.uio.no)

RegClim’s main emphasis is to produce scenarios for climate development in Norway and adjacent sea areas, including parts of the Arctic. The purpose is to enable quantitative assessments of potential impacts of climate change in the region on the natural environment and on society. There are, however, considerable uncertainties associated with such scenarios due to natural climate variability or “chaos” (I), errors resulting from inadequate process descriptions in climate models (II), and future assumptions resulting in radiative forcing of the climate system (III). These uncertainties will manifest as a statistical spread in the estimates of all climate relevant parameters. Statistical spread connected with I and III is unavoidable, but the spread caused by III must be kept at a reasonable level. Spread caused by II should, however, be as small as possible by improving the models. Statistical spread is closely related to risks for extreme events, and large model uncertainties produce wrong assessments of risk.

In this presentation we will present plans for RegClim Phase III, along with selected results so far. In particular we will present results from a combination of two dynamically downscaled scenarios. Finally, we will briefly mention results from climate response of aerosol particles and from theoretical studies of regional climate predictability. Results from studies of the Atlantic Meridional Overturning Circulations and from empirical downscaling of a large ensemble of IPCC climate scenarios will be presented in separate talks.

AerOzClim Module II: Description of aerosol particles and their physical properties in a atmospheric global climate model (CCM-Oslo).

Trond Iversen, Øyvind Seland, Alf Kirkevåg, Jon Egill KristjanssonDepartment of Geosciences, University of Oslo, P.O. Box 1022, Blindern, N-0315 Oslo. (trond.iversen@geo.uio.no)

The potential influence of anthropogenic aerosol particle on climate is designated by IPCC TAR as an important source of climate model uncertainty. There are several reasons for this. Particles are partly realeased directly into air and partly produced in situ by gas-to-particle physico-chemical reactions. They are subject to quick depletion by precipitation scavenging, and their tropospheric residence times are generally only a few days to a week. Also they can be produced and processed otherwise in cloud droplets. Hence, the space-time distribution of aerosols is strongly influenced by clouds, and clouds and their properties are themselves very uncertain in atmospheric numerical models.

One potential climate effect of aerosols is the particles’ reflection and absorption of solar radiation; the direct effect. To calculate the radiative forcing due to this requires knowledge of particle composition as a function of particle size, in order to estimate the reflectivity and absorptivity for each wavelength of light. Another potential climate effect of

aerosols is linked to the particles’ ability to extract water from water vapor and thus act as cloud condensation nuclei (CCN). More CCNs may cause smaller and more reflective cloud droplets (first indirect effect), less efficient precipitation release and thus more cloudiness (second indirect effect).

In AerOzClim we develop new methods that are simplified compared to “first principles”, but still more accurate than in earlier climate models. In this presentation we will demonstrate the principles behind the schemes along with results from designed experiments for the ongoing intercomparison exercise that prepares for the next IPCC report (Aerocom).

Combined Observational and Modeling Based Studies of the Aerosol Indirect Effect (COMBINE)

Jón Egill Kristjánsson 1 , Trude Storelvmo1, Mona Johnsrud2, Gunnar Myhre1,2, Frode Stordal1, Ann-Mari Fjæraa2

1 Department of Geosciences, University of Oslo2 Norwegian Institute for Air Research, Kjeller

Humans influence the climate in various ways, e.g., by releasing so-called greenhouse gases into the atmosphere and by introducing new particles (aerosols) into the atmosphere. In this way the number of cloud condensation nuclei (CCN) is enhanced, leading to smaller and more numerous cloud droplets, which reflect more solar radiation. The impact of this “indirect effect” of aerosols is, by current estimates, only surpassed in magnitude by greenhouse gas forcing, but with opposite sign. At present, there is great uncertainty concerning many aspects of the indirect effect. This is due to a combination of poorly understood physics, insufficient measurements and oversimplified model treatments. In Norway, the modeling aspect has been addressed within the RegClim project, and will be worked on further in AerOzClim. To strengthen the research in this area, we have introduced an integrated effort combining climate modeling and the use of satellite observations. To improve the simulations of the indirect effect, prognostic equations will be developed for cloud droplet number and ice crystal number. The satellite observations will serve to identify and evaluate the magnitude of the indirect effect, as well as to validate crucial model parameters, such as aerosol optical depth, cloud optical depth, liquid water path and CCN. These quantities are obtained from the MODIS instrument onboard the Terra and Aqua satellites.

The Nordic Seas; a gateway between the North Atlantic and Arctic Oceans

Cecilie Mauritzen, Trond Dokken, Helge Drange, Peter M. Haugan and Solfrid S. Hjøllo

The Nordic Seas (here defined as including the Norwegian, Greenland, Iceland and Barents Seas) can be considered a gateway between the North Atlantic and Arctic Oceans, and quantifying and understanding the variability of the fluxes between these regions is considered an important component of understanding the global climate system. Within Norwegian Ocean and Climate Project (NOClim) processes which govern oceanic heat

transport towards the Nordic Seas, and which provide the basis for atmospheric heat transport from the Atlantic sector towards northern Europe, are investigated.

To examine the forcing, structure and sensitivity of the Atlantic Meridional Overturning Circulation in response to buoyancy forcing, internal mixing and wind driving, numerical modelling experiments in idealized and realistic basin configurations will be performed. The Nordic Seas represents a (fairly) well-sampled end-member of the AMOC. Therefore, the inflow and outflow properties across the Greenland-Scotland Ridge serve as one – the northern – check-point of climate GCMs.

NOClim investigates the relevant processes that led to large and abrupt amplitude climatic shifts. Climate transitions are identified by reconstructing oceanographic variables across three different climate transitions that are all easily detectable in the paleo-record, and where each climate transition represents a transition from different initial conditions. Each event will be identified in all the cores, and will be subject for detailed investigation and chemical/sedimentological/ biological analysis. Proxy data collected from surface samples are calibrated with present day hydrography. Vertical temperature and salinity profiles through the main inflow and outflow areas between Iceland, the Faroes and Shetland during three major climate transitions are estimated, and quantitative reconstructions of the transport of surface and deep water through the channels connecting the Nordic Seas and the North Atlantic during climate transitions will be deduced from this study.

Historical data is assessed in order to investigate whether significant change to our high-latitude (specifically the Nordic Seas) climate system is presently underway. Emphasis is on the oceanic part of the climate system, and the goal is to contribute to the understanding of the physical conditions that do (or do not) influence the oceanic heat fluxes in the Nordic Seas. Analysis shows that there have been very significant hydrographic changes in the Nordic Seas in the 20th century, and there is a need to establish whether the pathways or their strength may have changed.

CLIMATE AND PRODUCTION OF MARINE RESOURCES (CLIMAR)Webjørn Melle, Morten Skogen (Havforskningsinstituttet)

The project focuses on the vulnerability of the Nordic Seas pelagic food web to climate change, and especially on the effects of climate on the growth and migrations of the Norwegian spring spawning herring stock which is potentially one of the most valuable harvestable living marine resources in the North Atlantic. The Nordic Seas ecosystem is particularly at risk with respect to climate change because its oceanographic characteristics are closely coupled to fundamental ocean-atmosphere interactions in the Polar regions where the meteorological and oceanographic manifestations of climate change are very pronounced.

Fisheries managers are increasingly aware of the potential influence of climate fluctuations on the sustainable levels of exploitation for fish stocks. However, there are still few cases where climate conditions are formally taken into account in the setting of management targets. Although there are statistical relationships between historical aspects of the dynamics and distribution of some stocks and indices of climate status, the oceanographic and ecological justification for these relationships is lacking. Often, such relationships fail in the event of abrupt changes in climate or ecological conditions, suggesting that key processes are not characterised by the particular climate indices used, and hence the relationships cannot be relied on in the future.

One of the most significant events in European fisheries of the 20th century, both ecologically and economically, was the collapse and subsequent recovery of the Norwegian spring spawning herring stock inhabiting the Nordic Seas. There is no doubt that over-exploitation hastened the collapse of this stock in the 1960’s and 1970’s, but there is also evidence that climate during this period was adverse for the herring, and it is likely that a combination of the two factors sealed the fate of the stock.

The beginning of the decline of the Norwegian spring spawning herring in the mid-1960’s coincided with a dramatic change in the climate of the Nordic Seas. The Arctic front, separating the surface Atlantic waters in the eastern Norwegian Sea from the cold waters north and east of Iceland moved steadily east so that an increasing proportion of the former habitat of the herring was covered by cold, low salinity water. At the same time as the increase of the Greenland Sea outflow in the late 1960’s, there was a dramatic decline in the abundance of Calanus north of Iceland, and the summer migration of herring to the area ceased.

Calanus is the main prey of the Norwegian spring spawning herring during its feeding migration in the Norwegian and Iceland Seas. The timing of the phytoplankton vernal bloom and the seasonal production of Calanus may differ by more than three months from east to west in the Nordic Seas, and by several weeks between years. The time period spent in surface waters by adults and older copepodite stages is brief. The herring, being strongly selective towards the older Calanus, has to time its feeding migration according to geographical diversity in the timing of the seasonal production cycle of its prey. Which conditions favour efficient exploitation of the Calanus production by herring?

The overall objectives of the project are to: establish the processes which constitute the coupling between climate fluctuations and the

growth and migration patterns of the Norwegian spring spawning herring in the Nordic Seas,

develop models of the oceanography, plankton food web, and fish growth and migration that will allow a quantitative analysis of the climatic factors involved, and prognoses of the consequences of future climate scenarios.

RegClim: Trends and internal variability in a cmip2 ensemble simulated with the Bergen Climate Model

A. Sorteberg, H. Drange*, N.G.Kvamstø, T. Furevik Bjerknes Center for Climate Resear ch, University of Bergen.*Also NERSC, Bergen.

An ensemble of five climate change simulations of each 80 years has been carried out with the Bergen Climate Model (BCM). The 5 ensemble members have all been integrated with a 1% increase per year in CO2 content with 353ppm as initial level. But they have been started from different initial physical states (taken from a control run). The spread between the ensemble members in simulated regional (and zonal mean) climate changes seem to be a function of the ensemble mean response. The relation we see is that

large ensemble mean response is associated with large ensemble spread and vice versa for small mean response. We observe the largest spread in wintertime over land in the mid and high latitudes.

Furthermore, the spread in zonal mean trends are a strong function of sampling time. Our data show that the trend spread between the ensemble members is reduced by a factor of 2 by increasing sample time from 50 to 70 years and a reduction of 80-90% is found by reducing sampling time from 20 to 75 years.

The regional climate warming pattern in individual ensemble members showed increased similarities with increasing sampling time. For Europe the pattern correlation increased with a factor of about 1.5 by increasing sampling period from 20 to 75 years. However, with a sampling period of 75 years the mean pattern correlation for individual ensemble members is less that 0.8.

Our findings suggest that climate change projections over a period of less than 50 years will be strongly influenced by chaotic (or unpredictable) internal climate variability. Thus multi-model spread on these time-scales may partly be influenced by real model differences and internal (natural) chaotic variations.

ECOSYSTEM MANIPULATIONS AS A TOOL IN CLIMATE RESEARCH

Arne Stuanes1, Richard F. Wright2, Heleen de Wit3, Lars Hole4, Øyvind Kaste2 & Jan Mulder1

1 Department of Plant and Environmental Sciences, Agricultural University of Norway,2 Norwegian Institute for Water Research, 3 Norwegian Institute for Land Inventory,

4 Norwegian Institute for Air Research

Large-scale ecosystem experiments are a powerful tool to study environmental effects on ecosystems. Norway has a long experience with large-scale experiments in forest, lake and heathland ecosystems and has an international reputation in this field. Large-scale ecosystem experiments started in the 1970s with research on effects of acid rain on forest and fish (SNSF project). In the SNSF project large field experiments included addition of artificial acid rain in forests and manipulations in small catchments. This was followed by the RAIN project (1984-93) where a small upland catchment with trees was covered by a roof to study the reversibility of acidification. Later, ecosystem-scale experiments with nitrogen (addition and exclusion) in forest (NITREX) and acidification of lakes (HUMEX) were established. In another large- scale experiment in forest aluminium was added to study the effect of this metal on a closed forest stand. Experiments to study the effects of climate change began in the 1990s with the CLIMEX project (glass house covering a forested catchment where CO2 concentration and air temperature were increased) and the THERMOS project (manipulation of heat budget for a whole lake).

Results and experiences gained from these large-scale ecosystem experiments have led to use of this approach in the new Norwegian climate change effects project “Effect of climate change on flux of N and C: air-land-freshwater-marine links (CLUE)”. In the CLUE project we will manipulate snow cover, freeze-thaw cycles, and soil wetness in mini-catchments to simulate future climate scenarios of increased frequency of freezing and

thawing cycles in winter, melting episodes due to increased temperature in winter and increased summer and autumn precipitation.

Such controlled large-scale experiments give direct information on effects of different environmental factors on an ecosystem level. They are necessary for evaluation of long-term effects in a short-term perspective. Such experiments are also essential for testing of models that later can be used for extrapolations in time and space.

ECOBE 2003-2006 (Effects of North Atlantic Climate Variability On the Barents Sea Ecosystem) – preliminary results from the first year of the project.

Svein SundbyInstitute of Marine Research and Bjerknes Centre for Climate Research

The over-all goal of this integrated project is to understand and quantify the impacts of Arctic climate variability on trophic transfer and ecosystem structure of the Barents Sea in order to improve the prediction of growth and recruitment on key fish species. Inflow of Atlantic plankton-rich water from the Norwegian Sea onto the Norwegian continental shelves is of major importance for the growth and survival of fish stocks along the Norwegian coast and in the Barents Sea. Additionally, ocean climate parameters as temperature, light conditions, wind-induced mixing and turbulence are important abiotic parameters for individual growth of marine organisms. In the ECOBE project, we use integrated physical-biological models to explore influence of the various processes of importance for growth and recruitment in fish. Laboratory experiments produce important input data to the coupled models. The model results are compared to survey data of pelagic juveniles from the region. Here, we present preliminary results after the first year of the project. A first-generation individual-based model simulates growth and survival of larval fish from the spawning areas along the Norwegian coast till the stage of pelagic juveniles when they are spread out in the Barents Sea.

The new IGBP programme IMBER (Integration of Marine Biogeochemistry and Ecosystems Research).

Svein SundbyInstitute of Marine Research and Bjerknes Centre for Climate Research

The work with developing the IMBER Science Plan and Implementation Strategy, the new IGBP programme, is now being finalised and submitted to the IGBP Council and Secretariat. The work with the plan has been carried on over the last two years. The IMBER project is being formed as an activity jointly sponsored by IGBP and SCOR (Scientific Committee on Oceanic Research). The IMBER project goal is to understand how interactions between marine biogeochemical cycles and ecosystems respond to and force global change. To achieve this goal it will be important to understand the mechanisms by which marine biogeochemical cycles control marine life and, in turn, how marine life controls biogeochemical cycles. In this light, IMBER research aims to identify key feedbacks from marine biogeochemical cycles and ecosystems to other components of the Earth System. Included in the IMBER plan is to explore the effects of global change on human activities and welfare. IMBER will collaborate

with a number of other international programmes, particularly GLOBEC Global Ocean Ecosystem Dynamics), SOLAS (Surface Ocean – Lower Atmosphere Study) og CLIVAR (Climate Variability and Prediction) under World Climate Research Programme.

Salt and Freshwater transport in the Arctic Ocean and the Nordic Seas

Svein Østerhus, (ngfso@uib.no)Bjerknes Centre for Climate Research, University of Bergen

The main fluxes of salt/freshwater between the North Atlantic, the Nordic Seas and the Arctic Ocean are measured by means of instrumented moorings in the Scotland-Greenland Gap, the Barents Sea opening, and in the Fram Strait. As a result relative accurate flux estimates of salt and heat can be given for the Atlantic inflow to the Nordic Seas. The cooling and freezing in the Arctic converts the Atlantic Water into a fresh surface layer (ice) and a salty deep water. Freshwater is added to the surface layers by atmospheric transport and river runoff. The inflow of low saline water from the Pacific Ocean through the Bering Strait and transport from the Baltic Sea via the Norwegian Costal current also add freshwater into this system. The relative salty deep water returns to the Atlantic Ocean by overflowing the Scotland-Greenland ridge and the fresh surface layer returns via the East Greenland Current and through the Canadian Archipelagos. The main of the freshwater leaves the Arctic Ocean through the Fram Strait as ice and liquid water. The spreading of the freshwater in the Greenland and Iceland seas is thought to play an important role in the deepwater formation taking place in these seas. A freshening of the intermediate water is observed in the Norwegian Sea since the mid 70’s and the density is decreasing. As a consequence the overflow through the Faroe Bank Channel is reduced.

Postere

Sea Ice Thickness Measurements with ULS in the Barents Sea

by

Povl Abrahamsen, Svein Østerhus, and Tor Gammelsrød

Moored upward-looking sonar (ULS) is one of the most promising tools for monitoring long-term, as well as interannual and seasonal changes in ice thickness. Annual moorings with a current meter and a ULS were deployed in the Northwestern Barents Sea around 77°55'N 28°20'E by the Norwegian Polar Institute from 1993-1996. This yielded a two-year time series of ice drafts, which was processed and analyzed at the

Geophysical Institute, Univ. of Bergen. As preliminary processing, using algorithms developed at the Norwegian Polar Institute primarily for use with data from Fram Strait, proved unreliable, a new algorithm for processing this sort of data using satellite-derived ice concentrations from the SSM/I sensor was developed. The resulting data appears, as least subjectively, to result in significantly lower errors. While we believe that in its current form this algorithm works best for data from the Barents Sea, we do have some suggestions for applying it to other regions. The processed data set shows significant differences in draft between the two years. While the mean ice draft (including open water) for February-May 1995 was 2.61 m, the corresponding value for 1996 was 1.56 m. Although there was a difference in instrumentation, this cannot account for such large differences in draft. Thus, we believe there was a significant change in circulation patterns between the two years, affecting the inflow of Atlantic water, which largely controls the ice conditions of the Barents Sea.

Economy and Ecology of Agriculture in a Changing Climate: The Norwegian project EACC (2003-2008)

Forfattere: Bleken Marina A, Bakken LR, Haugen LE, Lundekvam H, Rørstad PK, Sørensen R, Vatn A.

EACC is an interdisciplinary project which explores the possible consequences of climate change for the economic and environmental performance of Norwegian agriculture. The environmental factors included are soil erosion, nitrate leaching and the sinks and sources of greenhouse gases. The integrated economic and ecological modelling allows an inspection of economic outcome, farmers decisions and their effects on the environmental variables in a future climate. The project also includes an investigation of the past: erosion and P losses during the past 2000 years is investigated by sediment core analyses. The patterns of the past soil erosion will be compared with documented changes in the climate and agronomy.

Emission from International Sea Transportation and Environmental ImpactStig B. Dalsøren , Jostein K. Sundet, Ivar S. A. Isaksen and Tore F. Berglen,

Department of Geosciences, University of Oslo, P.O. Box 1022, Blindern, N-0315 Oslo. (s.b.dalsoren@geo.uio.no)

Øyvind Endresen, Eirik Sørgård and Gjermund Gravir

Det Norske Veritas, Veritasveien 1, N-1322 Høvik, Norway

The impacts of emissions from cargo and passenger carrying ships in international trade are studied in

collaboration with Det Norske Veritas. Emissions from ships in international trade are not subject to

regulations as part of the Kyoto agreement. The International Maritime Organisation (IMO) has

introduced and is planning restrictions for specific areas (sulphur content in fuel) and new ship engines

(nitrogen oxides). Bearing in mind that ship emissions are one of the most rapidly increasing emission

sectors, it is also of interest to evaluate the predicted future importance compared to other sectors.

Perturbations of the global distribution of ozone, methane, sulphur and nitrogen compounds due to

ship emissions are estimated using the global 3-D CTM with interactive ozone and sulphur chemistry.

Ozone perturbations are highly non-linear, being most efficient in regions of low background

pollution. Different data sets are used as input for the model studies (e.g. AMVER, COADS), leading

to highly different regional perturbations. Maximum perturbation of ozone is obtained in the North

Atlantic and in the North Pacific during summer months. In contrast to the AMVER data the COADS

data gives particularly large enhancements over the North Atlantic. Ship emissions reduce global

methane lifetime by approximately 5 %. CO2 and O3 give positive radiative forcing (RF), and CH4

and sulfate give negative. The total RF is small (0.01 - 0.02 W/m2), but connected with large

uncertainties. Increase in acidification due to increased sulfate deposition is in average 3% and up to

10% in certain coastal areas.

Monitoring the Ice Shelf water overflow:Importance for Antarctic ice cap melting and thermohaline circulation.

byTor Gammelsrød, Svein Østerhus and Povl Abrahamsen

Ice Shelf Water (ISW) is the final product of the melting process underneath the floating ice shelves in the Antarctica. Recent drastic break-ups of the Larsen ice-shelf in the Weddell Sea has vitalised the question if this melting has increased. The most efficient production of ISW takes place under the immense Ronne – Filchner Ice shelves in the Southern Weddell Sea. The corresponding ISW flow out of the region was located in 1977, and a key location for long term monitoring was identified. Since then we have succeeded in occupying this station with instrumented moorings for about 5 years, which have given us valuable information of variability of the sub-ice shelf and continental shelf circulation. However, in addition to serve as an indicator for Antarctic ice-cap melting, it turns out that the ISW flow contribute to the formation of the Antarctic bottom water. Therefore it is driving the thermohaline circulation, which has a great impact on the global climate. There are several processes and regions in the Antarctic of importance for the bottom water formation. However, recent international efforts indicate that the ISW overflow and its cascading towards large oceans depths as a bottom trapped jet entrain waters from above, increasing the volume transport by a factor of about 2.5. The resulting volume transport estimates indicate that the processes involving ISW is dominating the deep and bottom water formation in the Antarctic.

Atmosphere-Ice-Ocean Interaction Studies in frozen Svalbard fjords

S. Gerland1, K. Widell2, P. Haugan2, F. Nilsen3, J-G. Winther1, K. Edvardsen4, M. McPhee5, & J. Morison6

1: Norwegian Polar Institute, Polar Environmental Centre, Tromsø, Norway 2: Bjerknes Centre for Climate Research and Geophysical Institute, University of Bergen, Norway3: University Courses on Svalbard, Longyearbyen, Norway4: Norwegian Institute for Air Research, Polar Environmental Centre, Tromsø, Norway5: McPhee Research Company, Naches, USA6: Applied Physics Laboratory, University of Washington, Seattle, USA

The project Atmosphere-Ice-Ocean Interaction Studies (acronym “AIO”, duration 2002-2005), is designed to provide a rigorous basis for selected sea ice-related aspects of climate hypotheses. The Norwegian project partner’s activities are funded by the Research Council of Norway, whereas the complementary U.S. activities are funded by the National Science Foundation under a US-Norway collaboration scheme.The main thrust of the project is to perform controlled field experiments using Svalbard fjords as a natural laboratory. The scientific objects include (1) to test proposed parameterizations for ice-ocean heat exchange during conditions of ice freezing, (2) to measure vertical heat and salt fluxes and develop parameterizations of ice-ocean heat exchange during melting, and in conditions when sea ice is exposed to saline water which is colder than the melting temperature of the fresher ice, (3) to investigate the role of penetrating solar radiation, in particular effects of albedo and snow cover, in determining under-ice ocean temperature structure and bottom ablation of sea ice, and (4) to study polynya processes where the atmosphere-ice-ocean processes are interactively linked to water mass formation and movement. Preliminary results from the first set of field campaigns, conducted in Kongsfjorden and van Mijenfjorden, show generally different hydrographic conditions for the two studied systems on large, medium and small scales. These differences can be explained by the principal settings of the fjords, resulting in different ice formation and current patterns/strengths.

Impact of different dust production mechanisms on downwind dust size distributions

Alf Grini

Department of Geosciences, University of Oslo, P.O. Box 1022, Blindern, N-0315 Oslo. (alf.grini@geo.uio.no)

C. Zender

Department of Earth System Sciences, University of California, Irvine

A tracer transport model has been run with several different dust production schemes to try to explain

the discrepancy between modelled and measured aerosols at remote sites. The focus is in particular on

the difference between statical production schemes in which all dust particles have the same size

distribution, and dynamical schemes in which the size distribution can vary as a function of wind

speed and soil size distributions. Comparisons are made with campaign data. It is found that the type

of soil adopted has a significant influence on the distribution downwind.

Local temperature and precipitation scenarios for Norway

Inger Hanssen-Bauer, Eirik J.Førland and Ole Einar Tveito Norwegian Meteorological Institute, P.O.Box 43 Blindern, N-0313 Oslo, Norway.

Local temperature and precipitation scenarios may be deduced by applying empirical downscaling. The basic idea within empirical downscaling is that local climate is conditioned by large-scale climate and by local physiographic features as topography, distance to coast and vegetation. At a definite locality, links should thus exist between large-scale and local climate. Empirical downscaling consists of revealing empirical links between large-scale patterns of climate elements (predictors) and local climate (predictands), and applying them on output from global or regional climate models. Successful empirical downscaling is thus dependent on long reliable series of predictors and predictands. Within RegClim, scenarios from several global climate models are empirically downscaled for the Nordic region.

The downscaled scenarios in this presentation are based upon the GSDIO-integration with the ECHAM4/OPYC3 climate model. These scenarios indicate an average annual warming rate of 0.2-0.5ºC/decade up to 2050 in Norway. The rates are generally smallest in southern Norway along the western coast. They increase in the inland and in the northern parts. The highest rates are found in the northernmost parts and in the inland valleys (0.5ºC/decade). The precipitation scenarios for Norway indicate an average annual increase of 0.3-2.7% / decade during the next 50 years. The changes are largest and highly significant along the western and northwestern coasts. They are smallest and not statistically significant in southeastern Norway. Both temperature and precipitation scenarios show a seasonal variation.

Corresponding author:Eirik J. Førland, met.no, P.O.Box 43 Blindern, N-0313 Oslo, Norwaye-mail: e.forland@met.no

The Significance of the North Atlantic Oscillation (NAO) for Sea-salt Episodes and Acidification-related effects in Norwegian Rivers.

ATLE HINDAR1, KJETIL TØRSETH2, ARNE HENRIKSEN3, AND YVAN ORSOLINI2

1Norwegian Institute for Water Research, Grimstad, 2Norwegian Institute for Air Research,3Norwegian Institute for Water Research, Oslo

Acidification of Norwegian surface waters, as indicated by elevated concentrations of sulphate and a corresponding reduction in acid neutralising capacity and pH, is a result of

emission and subsequent deposition of sulphur and nitrogen compounds. Episodic sea-salt deposition during severe weather conditions may increase the effects of acidification by mobilising more toxic aluminium during such episodes. Changes in climatic conditions may increase the frequency and strength of storms along the coast thus interacting with acidification effects on chemistry and biota. We found that the North Atlantic Oscillation (NAO) is linked to sea-salt deposition and sea-salt induced water chemistry effects in five rivers. Particularly, toxic levels of aluminium in all rivers were significantly correlated with higher NAO index values. Further, temporal trends were studied by comparing tendencies for selected statistical indices (i.e. frequency distributions) with time. The selected indices exhibited strong correlations between the NAO index, sea-salt deposition and river data such as chloride, pH and inorganic monomeric aluminium, pointing at the influence of North Atlantic climate variability on water chemistry and water toxicity. The potentially toxic effects of sea-salt deposition in rivers seem to be reduced as the acidification is reduced. This suggests that sea-salt episodes have to increase in strength in order to give the same potential negative biological effects in the future, if acid deposition is further reduced. More extreme winter precipitation events have been predicted in the northwest of Europe as a result of climate change. If this change will be associated with more severe sea-salt episodes is yet unknown.

Norwegian Ocean and Climate project

Solfrid Sætre Hjøllo, NOClim Scientific Coordinator, Bjerknes Centre for Climate Research

Norwegian Ocean and Climate project (NOClim) is a continuation of the NOClim Phase I project, but focussing all available resources on the fundamental and overarching issue of Atlantic Water flow towards and into the Nordic Seas. Active partners are Bjerknes Centre for Climate Research, Institute of Marine Research, Nansen Environmental and Remote Sensing Center, Norwegian Meteorological Institute, Norwegian Polar Institute and University of Bergen. The principal objective of the project is to significantly improve our understanding of processes which govern oceanic heat transport towards the Nordic Seas, and which provide the basis for atmospheric heat transport from the Atlantic sector towards northern Europe. The subgoals are i) to elucidate how stable the Atlantic Meridional Overturning Circulation (AMOC) is to human induced greenhouse warming, ii) to identify whether rapid climate transitions in the past were associated with changes in the overturning rate in the Nordic Seas and iii) to investigate whether the balance of evidence (from observations, process understanding and models) indicates that abrupt changes are underway or likely to happen in the near future.

The project will be executed by combining theory and numerical modelling with analyses of recent instrumental data and reconstructions from proxy data. The project is organised in three modules:

Module A: Theory and modelling of meridional oceanic heat transport Module B: Analysis of abrupt changes in the past Module C: Analysis of modern variability and detection of significant changes

The Polar Ocean Climate Processes (ProClim) project is integrated with NOClim as its module D. However, ProClim is funded and reported separately.

NOClim intends to serve as an authoritative source of information and advice to the Research Council and the public concerning the difficult issues of possible rapid climate change related to ocean circulation. More information can be found at the project web-pages www.noclim.org

Polar Ocean Climate Processes

Solfrid Sætre Hjøllo (Bjerknes Centre for Climate Research)

Polar Ocean Climate Processes (ProClim) is addressing climate processes in the geographical region of the Polar Climate Research Programme by means of observations, process modelling, parameterization, analyses of observations/model fields and synthesis. The principal objective of the project is to quantify and understand climate processes in polar marginal seas, with emphasis on the western Barents Sea, Svalbard region and Greenland Sea in order to improve our understanding of future regional and global climate and its predictability. Sub-goals:

To identify the parameters setting the mode of Greenland Sea convection. To understand dense water formation on polar shelves, and develop high resolution atmosphere, ice and

ocean model tools which properly describe the processes. To measure major cold outflows from the shelf region and understand the mixing processes determining

their fate. To assess the variable contributions to deep mixing and sinking from shelves and in the deep ocean and

understand the regional interaction between the processes.

The project is organized in four work packages: 1) Deep mixing and sinking, 2) Water mass formation on shelves, 3) Slope convection and overflows off shelves and 4) Integration by (basin scale) models, observations and theory. Work packages 1 to 3 will provide in-depth understanding of those regional components of global thermohaline ocean circulation which are believed to be especially important for ocean heat transport and sea ice extent in the northern seas. The fourth work package will use large scale models and observations to quantify the variability and understand the interaction between processes.

The project team will use their unique field experience and facilities in Svalbard waters, the Greenland and Barents Seas, in combination with theoretical and modelling. The project is funded by Norwegian Research Council, Polar Climate Research Programme, and the duration is 2003-2006. More information can be found on http://www.gfi.uib.no/ProClim

Phenology as an indicator of climate change effects, PhenoClim

K.A. Høgda, S. R. Karlsen, and I. Solheim.Norut IT, N-9291 Tromsø, Norway

Fennoscandia is characterized by high climatic diversity and comprises nemoral zone in south to southern arctic zone in north. The contrast in climate and vegetation from coast to inland and along the altitude gradient is high. Accordingly, the region is well suited for studying effects of climatic change.

The PhenoClim project started in 2003 and will last for five years. PhenoClim is financed by The Research Council of Norway. Eight different institutes in Norway participate. The project includes scientists in physics, biology, computer science, economy, and sociology. The project is presented on web at: http://www.itek.norut.no/projects/phenology/index.html.

The objective of the PhenoClim project is to use in-situ and satellite data to establish knowledge about ongoing large-scale changes in the phenological cycle and primary production on a national and regional level. Phenological changes are studied in order to investigate selected biological, economical, and social consequences of observed and predicted climate changes.

In the first year of the project most of the work has been concentrated on collecting data (that as far as legally possible will be made available on internet). Phenological data is collected by more than 150 schools and 5 Planteforsk stations around Norway. In cooperation with the national parks on Kola Peninsula unique historical phenological data series, the longest going back to the 1930thies, are made available for the project. Satellite data from 1981-2003 (NOAA AVHRR 8 km resolution), 1998-2002 (Spot 1 km resolution) and 2000-2003 (MODIS 250 meter resolution) have been collected and is at present being analyzed.

In southern Fennoscandia results indicate a surprisingly high change in the start of spring during the period from the beginning of 1980 to today. In most of southern Fennoscandia, the spring now starts more than two weeks earlier compared to the early eighties. In addition, we have also detected a delay trend in mountain areas in southern Norway and in continental parts of northern Fennoscandia. This trend is also supported by the in-situ phenological data from Kola Peninsula. Even more important, the phenological data from Kola Peninsula is also indicating cyclic trends in the onset of spring (the last 20 years on the delay phase of the trend), and earlier autumn. These trends are now to be further analyzed against meteorological data.

IMPACTS OF CLIMATE CHANGE ON NITROGEN LEACHING FROM UPLAND ECOSYSTEMS

Øyvind Kaste1, Arne O. Stuanes2, Richard F. Wright1, Lars Hole3, Ståle Haaland2 & Jan Mulder2

1 Norwegian Institute for Water Research, 2 Department of Plant and Environmental Sciences, Agricultural University of Norway, 3 Norwegian Institute for Air Research

Elevated levels of inorganic nitrogen (N) in runoff water may have negative environmental effects in both freshwater and marine ecosystems. In acid-sensitive areas, leaching of nitrate (NO3

-) contributes to surface water acidification by mobilising hydrogen and inorganic aluminium ions from soil. Increased NO3

- output to surface waters will also alter the nutrient balance and possibly cause eutrophication problems in coastal waters, where N commonly is the limiting element for primary production.

Non-forested upland catchments (typical for large areas in southern Norway) often have a restricted capacity to retain N from atmospheric sources, owing to their thin and patchy soils, sparse vegetation cover, high precipitation amounts and short growing season. In such marginal areas, the predicted change in ambient climate might have significant effects on catchment N cycling and subsequent losses of inorganic N to surface waters.

Long-term increases in air temperatures and precipitation amounts, as predicted by the REGCLIM project, will have several implications for production, consumption and mobility of N in catchments. In the recently started climate project ‘Effect of climate change on flux of N and C: air-land-freshwater-marine links (CLUE)’ two major hypotheses will be tested: (1) increased frequency of freezing-thawing events (due to reduced snow accumulation in marginal areas) will increase the leaching of N from soil to water; (2) more frequent drought and re-wetting events during summer will increase decomposition/mineralisation and sub-sequent losses of N from the soils. These hypotheses will be tested by large-scale manipulation experiments (snow removal, insulation, irrigation) of upland mini-catchments (30-300 m2) at Storgama, Telemark.

IMPACT OF CLIMATE CHANGE ON SURFACE WATERS AND FJORDS

Øyvind Kaste, Nils R. Sælthun, Richard F. Wright, Line J. Barkved, Birger Bjerkeng, Jan Magnusson & Jarle Molvær

Norwegian Institute for Water Research (NIVA)

In this project we apply a linked-model approach to assess possible impacts of predicted climate change towards 2050 on hydrology and water quality in a river-fjord system (the Bjerkreim River + Estuary in Rogaland). The work is part of a Strategic Institute Programme (SIP) at NIVA (2002-2004), funded by the Norwegian Research Council. The basic concept here is to 1) calibrate and link four existing models to simulate hydrology and water quality at present climate, and 2) use this model platform to simulate possible effects of various climate change scenarios on the same river-fjord system. Implementation of climate scenarios is carried out in close collaboration with a research team from the Norwegian Meteorological Institute (met.no). The four models included are HBV, MAGIC, INCA and the NIVA Fjord Model. HBV uses catchment characteristics together with climate data (observations + scenarios) to produce hydrological time series (daily time steps). The MAGIC model uses deposition data, soil chemistry and climatic data to simulate runoff chemistry at present (1990-2000), in the past (1860-1990), and in the future (2000-2050). INCA, which is an integrated nitrogen (N) model for catchments, takes hydrological data from HBV, carbon/nitrogen dynamics from MAGIC, deposition + point source data, and simulates daily concentrations of inorganic N in the river. Finally, the NIVA Fjord model uses morphological data, climate observations, together with time series data from HBV and INCA to simulate effects of changed climate forcing, hydrology and N inputs on physical, chemical and biological conditions in the estuarine area.

Seasonal forecast of the North Atlantic Oscillation with stratosphere-troposphere models

Ina K. Thorstensen Kindem1,2

Yvan Orsolini 2

Nils Gunnar Kvamstø 2,1

Franscisco J. Doblas-Reyes 4

1. Bjerknes Centre for Climate Reseach2. Geophysical Insitute, University of Bergen3. Norwegian Institute for Air Research (NILU)4. ECMWF, Reading, United Kingdom

The North Atlantic Oscillation (NAO) is one of the most important factors controlling the North-Atlantic and European climate. Hence, improved seasonal predictability of the NAO will be important to society. Attempts to forecast the NAO on medium to seasonal time scale using troposphere-only models with boundary conditions of observed sea surface temperatures (SSTs) have not proven too successful, as documented in the PROVOST project

(PRediction Of climate Variations On Seasonal to interannual Timescales). However, recent statistical analysis has suggested that predictability of the NAO may be obtained from the state of the stratospheric Arctic Oscillation. We have run the atmospheric general circulation model ARPEGE with a well-resolved stratosphere and observed SSTs to investigate if we improve upon the predictability scores from the troposphere-only models presented in PROVOST. The technique for generating our model data set is similar to that in PROVOST. Preliminary results of how our modelled NAO index compares to both the NAO index from the PROVOST results and the observed NAO index from ERA-40 data will be presented.

Intercomparison of dynamic heights in the Nordic Seas fromobservations and climate model simulations between 1950 and 1990.

Korablev, A., H. Drange, J. A. Johannessen and O. M. Johannessen.

The dynamic height D, defined as the product of the depth difference between two surfaces of constant pressure and gravity, is a powerful quantity to derive the ocean circulation on both regional and global scales. The dynamic height can be readily derived from 3-dimensional observations of temperature and salinity, or from Ocean General Circulation Models (OGCMs). It can also be derived from remotely sensed sea surface height and the Earth's geoide. In the project, a unique Russian data set with about 130.000 hydrography observations covering the 20th century has been used to compute the mean value and the decadal variability of D of the Nordic Seas, i.e., from the ocean region between the Greenland-Scotland Ridge and south and the Fram Strait in north. Similar computations are made from an OGCM driven by daily atmospheric forcing fields from the period 1948 to present. Analyses of the observed and simulated D-fields show many temporal and spatial similaritiesbetween the two D-products. It is particularly evident that D varies on decadal time scales. The degree of variability in the region over the last 50 years is quantified. This quantification is of importance because it provides bounds on the accuracy of sea surface height determined by satellites and the Earth's geoide if reliable estimates of the remotely sensed ocean circulation are to be made.

Factors controlling UV radiation in Norway (FARIN)

A. Kylling, B. Kjeldstad, A. Dahlback, B. Johnsen, O. Engelsen, K. Edvardsen, A. Bagheri, B.-A. Høiskar, T. Danielsen, L.-T. Nilsen

Norway, including Svalbard, covers more than 20 degrees of latitude. The climate is quite diverse with little snow throughout the year in the far south and often snow cover well into the summer in the far north. Furthermore, the northern location makes Norway exposed to low ozone levels during the Arctic spring. Thus, it is a unique laboratory for studying how clouds, ozone, surface albedo, aerosols, latitude, and geometry of the exposed surface control the UV radiation levels. The FARIN project aims to study these factors by

1) quantifying how UV radiation is affected by clouds, snow and ozone as a function of latitude and season and identify and quantify any possible longterm changes in UV radiation and parameters that control UV radiation.

2) quantifying how aerosols affect surface UV radiation, with emphasis on coastal regions. 3) measuring and analyse the distribution of diffuse sky radiation for a coastal site in Norway. 4) measuring and analyse the UV radiation on horizontal and vertical surfaces. 5) performing a comprehensive instrument comparison with spectral and broad band meters included in the project .

The project is presented including obtained results.

Simulation of Erosion under 2 observed and 2 simulated Climates in the Follo Region Southeast Norway.

Lundekvam, Helge Egil,

Agricultural University of Norway, E-mail: helge.lundekvam@ipm.nlh.no

As part of the research program “Ecology and economy under a changing climate” (EACC) (2003-2007) at the Agricultural University, also soil erosion on agricultural land is simulated. In the following 4 climates were used: A) observed climate 1980-98 for Follo, B) simulated present climate 1980-98, C) simulated future climate 2030-48, D) observed climate (1980-98) at Ås in Follo (30 km south of Oslo). Climates A-C were provided May 2003 by the REGCLIM group in Oslo based on dynamic/empirical downscaling of GCM-simulations. Hydrological models used were the Swedish COUP model and AVRJUST3 (Lundekvam, 2002). Erosion model was ERONOR (Lundekvam, 2002). 2 soil types with slope 13% and length 100 m were used, but only data from the most erodible soil is given in the poster. Over 20 different tillage systems were simulated, but only 7 are presented.An evaluation of the simulated present climate B showed that precipitation was overestimated by 140-200 mm/year especially during the months July and August. The frequency of days with precipitation intensities less than 12 mm/day were also greatly overestimated. If realistic, this would sometimes seriously postphone essential field operations such as sowing and tillage. The frequency distribution of precipitation intensities greater than 12 mm were similar to observed climate. Comparing simulated future and present climates showed similar precipitation, an increase in temperature (+1.1 degrees), reduced snow cover and increased frequency of rain or snowmelt on soil with little or no snow cover. This increases the climatic erosion risk. Depending on hydrology model, soil type and tillage system used in the simulations, surface runoff will increase by 4-70%, soil loss by fallow (best expressing climatic erosion risk) will increase 40-60%, soil loss by ploughing autumn will increase 120-200%, soil loss by other systems will increase 40-150%. The increase will mostly happen during late autumn, winter and early spring. Thus agricultural systems with no till in autumn will reduce soil losses even more in future than at present compared with traditional autumn ploughing.

References:Lundekvam, H., 2002. ERONOR/USLENO-Empirical erosion models for Norwegian conditions. Report 6/2002. Agric. Univ. of Norway. ISBN 82-483-0022-6.

Comparing methane data from Ny-Ålesund with results from a regional transport model (MATCH)

Ine-Therese Pedersena,b, Kristina Enerotha, Erik Kjellströma, Ove Hermansenb, Kim Holménb

a Department of Meteorology, Stockholm University (MISU), S-106 91 Stockholm, Sweden.b Norwegian Institute for Air Research (NILU), N-9296 Tromsø, Norway.

E-mail: inep@misu.su.se

Methane (CH4) is an important greenhouse gas and a key molecule in tropospheric photochemistry. The global burden of atmospheric CH4 has risen dramatically since the preindustrial era, and recent measurements show global CH4 mixing ratios continuing to rise although the rate of increase has slowed over the past decade (Dlugokencky et al., 2001). The effect of methane transport source/sinks regions has been investigated on several stations in the CMDL network. In the Arctic, north of the polar front, winter meteorology is somewhat stagnant, with few storms and little precipitation to mix and clean the atmosphere (Raatz, 1991). Furthermore, the polar front limits how midlatitude surface sources can influence tracer fields in the Arctic. In this project the in situ methane measurements from the Zeppelin station in Ny-Ålesund (ZEP) on Svalbard (78°58´ N, 11°53´ E) are studied by comparing continuous gas chromatograph data and flask data to simulated CH4 concentrations from an atmospheric transport model. The model is used to investigate the distribution and transport of CH4 in and out of the Arctic region. The model is a 3-dimensional Eulerian transport model called Multiple-scale Atmospheric Transport and Chemistry modelling system (MATCH) from Robertson et al. (1999). The meteorological fields (wind, temperature and pressure) are taken from the European Centre for Medium range Weather Forecasts, ECMWF, available every 6 hours. The chosen domain covers most of the Arctic. Emission and boundary conditions for CH4 are taken from a global tracer transport model developed at "Centre for Atmospheric Science" in Cambridge, U.K, on 5 x 5 resolution (Warwick et al., 2002). The Zeppelin station is a part of the CMDL cooperative Air Sampling Network (Dlugokencky et al., 1994) and at least once a week flask samples are collected and analysed at NOAA CMDL in Boulder, Colorado by a GC/FID (http://www.cmdl.noaa.gov/). In addition to this a trajectory climatology for Svalbard will be used to investigate how the atmospheric flow patterns influence the observed CH4 concentration (Eneroth et al., 2003). By combining the climatology with the MATCH model, emission scenarios can be tested to identify region variability. One essential question being pursued is whether the high concentration of CH4 in wintertime in the Arctic are mainly caused by leakage from gas fields in Western Siberia, or originates from industrial activities further away in Russia or Europe.

ReferencesDlugokencky, E.J., Steele, L.P., Lang, P.M. and Masarie, K.A., 1994. The growth rate and distribution

of atmospheric methane. J. Geophys. Res. 99: 17,021-17,043Dlugokencky, E.J., Walter, B.P., Masarie, K.A., Lang, P.M. and Kasischke, E.S., 2001. Measurements

of an anomalous global methane increase during 1998. Geophys. Res. Letters 28:499-509Eneroth, K., Kjellström, E., Holmén, K., 2003. A trajectory climatology for Svalbard; investigating

how atmospheric flow patterns influence observed tracer concentrations. Physics and chemistry of the Earth, in press.

Raatz, W.E., 1991. The climatology and meteorology of Arctic air pollution. Pollution of the Arctic Atmosphere, edited by J.W. Sturges, pp. 13-42, Elsvier Sci., New York.

Robertson, L., Langner, J. and Engardt, M., 1999. An Eulerian Limited-Aewa Atmospheric Transport Model. J. Appl. Meteo. 38:190-210

Warwick, N.J., Bekki, S., Law, K. S., Nisbet, E.G. and Phyle, J.A. 2002. The impact of meteorology on the interannual growth rate of atmospheric methane. Geophys. Res. Letters 29 (20): Art. No. 1947OCT 15 2002

Keywords : methane; Arctic; transport model; tropospheric photochemistry; trajectory; Svalbard

OCTAS: Ocean Circulation and Transport Between North Atlantic and the Arctic Sea

Plag, H.-P., Drange, H., Gidskehaug, A., Johannessen, J., Nahavandchi, H., Omang, O.C.D., Pettersen, B.R., Solheim, D.

The Norwegian OCTAS Project running from 2003 to 2006 focuses on the ocean circulation in the Fram Strait and adjacent sea with the main objective to improve sea surface topography determination and to study the impact on ocen modelling. Up to the expected launch of GOCE in 2005 the gravimetric geoid is not known with sufficient accuracy to allow full use of the massive sea surface height information, which several satellite altimetry missions have regularly provided since the early 90-ies, in global analysis of the ocean circulation. However,in a few marine regions in the world sufficient in-situ information about the Earths gravity field exists to compute a more accurate geoid. The region covering the Northern North Atlantic and the Nordic seas between Greenland, Iceland, Norway and the UK, including the Fram Strait is one of those regions. One goal of the OCTAS Project is therefore to determine an accurate geoid in the Fram Strait and the adjacent seas. Together with the results from the on-going EU-funded project GOCINA, where in a similar approach an accurate geoid isdetermined for the region between Greenland and the UK, this will create a platform for validation of future GOCE Level 2 data and higher order scientific products. The new and accurate geoid is used together with an accurate Mean Sea Surface (MSS) to determine the Mean Dynamic Topography (MDT).

Another major goal of OCTAS is to use this new and accurate MDT for improved analysis of the ocean circulation. The ocean transport through the Fram Strait is known to play an important role in the global circulation. Gulf Stream water flows into the Nordic seas and feeds the formation of heavy bottom water that returns back into the Atlantic Ocean. Recent results have shown that changes in this bottom water transport may cause the inflow of Gulf Stream water to slow down or change into another stable circulation mode over a few decades. Such a change of the Gulf Stream with even a possible shut down of the heat transport towards high latitudes would have a huge impact on the North European climate. The OCTAS project, in coordination with the GOCINA project, attempts to ellucidate the role of the water exchange between the Arctic and Greenland Seas in this process.

Increased organic matter in surface waters of south-eastern Norway - a change in the quality of freswaters due to climate change?

Gunnhild Riise1, Dag Hongve2, Jan Mulder1, Ståle Haaland1, Dolly Kothawala1 and Arne Stuanes1

1Agric, Univ. of Norway, Dep. of Plant and Environmental Sci., P.O. Box 5003, 1432 Ås2Norwegian Institute of Public Health, P.O. Box 4404, 0403 Oslo

Clean, high quality surface water is an important resource for current and future generations. During the last few decades several countries in North-western Europe have reported increasing colour and concentration of organic matter (OM) in surface water (Forsberg and Petersen 1990, Freeman et al. 2001, Liltvedt et al. 2001, Riise and Hongve 2002). In Norway the strongest increase in colour has been found in the southern and eastern part of the country, especially in the period1997-2001, but there are also considerable increases in western Norway and Trøndelag. It has been hypothesized that the increase in OM is associated with climate change, but research on this topic is very limited. Others have suggested that decreases in global sulphate deposition (acid rain) and large-scale changes in land-use may explain the increase in OM.

OM in runoff represents an important problem because it affects physical and chemical properties of surface water. Reduced transmission of light affects primary production in water as well as biodiversity. Some waterworks have experienced a three-fold increase in colour, which causes increased demands on water treatment facilities.

Climate change may affect the dynamics of OM in soil water and catchment runoff in two different ways. Increased temperature and wetter summers may cause increased decomposition of soil organic matter, potentially resulting in increased production of CO2 and mobile organic compounds (Michalzik et al., 2003). More intensive precipitation events in autumn results in a greater proportion of streamflow being generated as surface runoff, which has greater concentrations of OM, and OM with more hydrophobic properties than percolation water from deeper soil layers. The observed increase in colour relative to OM, which is typical for episodes with increased precipitation, is probably related to increased content of high molecular weight compounds (Riise and Hongve 2002), but more research is needed. In the project “Effect of climate change on flux of N and C: air-land-freshwater-marine links (CLUE)" this will be studied by large-scale manipulation (snow removal, insulation, irrigation) of upland mini-catchments.

References:Forsberg, C. and Petersen, R.C., 1990. A darkening of Swedish lakes due to increased humus inputs during the last 15 years. Verh. Internat. Verein. Limnol. 24: 289-292Freeman, C., Evans, C.D., Monteith, D.T., Reynolds, B. and Fenner, N., 2001. Export of organic carbon from peat soils. Nature 412:785.Liltvedt, H., Wright, R. and Gjessing, E., 2001. Monitoring increasing colour in Norwegian surface waters – possible causes. VANN 36:70-77 (in Norwegian)Riise, G. and Hongve, D. 2002. Influence of hydrological flow pattern versus atmospheric sulphate deposition on water chemistry in low ionic forest lakes. Proceeding XXII Nordic Hydrological Conference, Røros 2002, NHP Report no. 47: 337-342.

Michalzik, B., Tipping, E., Mulder, J. Gallardo-Lancho, J.F., Matzner, E., Bryant, C.L., Clarke, N.,Lofts, S. and Vicente Esteban, M.A. 2003. Modelling the production and transport of dissolved organic carbon in forest soils. Biogeochemistry (in press).

Validation and Analysis of the Models for the Mean Dynamic Topography,the Mean Sea Surface Height and the Geoid in the Northern North Atlantic.

Solheim, D., Drange, H., Johannessen, J.A., Nahavandchi, H., Omang, O.C.D., Plag, H.-P.

The primary goal for the NFR funded project OCTAS, Ocean Circulation and Transport Between North Atlantic and the Arctic Sea, is to determine the Mean Dynamic Topography (MDT), which is the difference between the mean sea surface and the geoid.

The MDT provides the absolute reference surface for the ocean circulation. The improved determination of the mean circulation will advance the understanding the role of the ocean mass and heat transport in climate research.

Existing geoid, Mean Sea Surface (MSS) and MDT models have been collected and intercompared. Best combinations of models have been determined and synthetic geoid, MSS and MDT models have been computed. These models will be compared with the relevant state of the art models for the OCTAS study area.

A study of the Arctic Upper Troposphere/Lower Stratosphere (UTLS) region

K. Stebel (kerstin.stebel@nilu.no), G.H. Hansen, A. F. Vik, and Y. Orsolini, Institute for Air Research (NILU)

The tropopause region, the narrow transition layer between the troposphere and the stratosphere, plays an important role in climate and radiation processes. Cross-tropopause transport of trace gases have been intensively studied in the tropics and mid-latitudes. Only in recent years, motivated by the increasing efforts to clarify the role of dynamical patterns or equivalently, changes in tropopause altitude, in ozone trends, the tropopause in polar regions has got into the focus of scientific attention.

Here, we present the Arctic Upper Troposphere/Lower Stratosphere (UTLS) project, which started during 2003. The scientific results will be obtained in collaboration with research groups from Germany, Sweden and Finnland. The main objectives of this study are to further characterize the Arctic tropopause trends, using the most recent comprehensive meteorological dataset from the ECMWF and local meteorological measurements from radiosondes, ozonsondes, lidar and radar at high-latitude stations, and to achieve understanding of the processes leading to the high variability of the Arctic tropopause and Arctic UTLS temperatures in the last decade. Besides improving the quality of trend studies, the 1990s/early 2000s data set will be utilized to investigate Arctic stratosphere-troposphere coupling processes based on the thermal structure throughout the UTLS region, with emphasis on their dependence on hemispheric circulation patterns and wave propagation conditions. Furthermore, an investigation of meso-scale tropopause properties including stratosphere-troposphere exchange processes in the vicinity of the Scandinavian mountain ridge is planned.

We give a general overview of the background and status of the Arctic UTLS projects, including a presentation of the data sets available. Further, we show results from the algorithm implementation for the determination of the thermal, ozone and radar tropopause. First, very preliminary, geophysical outcomes will be presented.

Sea Ice Fluxes through the Fram StraitBy

Karolina Widell, Svein Østerhus and Tor Gammelsrød

Ice velocity in the Fram Strait has been monitored by use of a new method using moored Doppler Current Meters since 1996. Three years of data from 79 N 5 W in the period 1996-2000 are here presented and analysed with respect to the atmospheric driving force. A correlation between the ice velocity and the cross-strait sea level pressure (SLP) difference was R = 0.76 for daily means and R = 0.79 for monthly means is found and this result is used to formulate a simple linear model of the ice area flux. The model gives a mean ice area export for the period 1950-2000 of 850 000 km2/year, using NCEP/NCAR reanalysis SLP data. The cross-strait SLP difference exhibits a positive trend since 1950 of 10 % of the mean per decade indicating increased ice area export. We combine the modelled area flux with 10 years of ice thickness recordings from Upward looking Sonars to compute the ice volume flux which is found to be 200 km3/month during the last decade, without any significant trend.

The role of climatic variation in the dynamics and persistence of an Arctic predator – prey / host –parasite system

Nigel G. Yoccoz *†, Eva Fuglei ‡, Rolf A. Ims †, Audun Stien †, Jan-Gunnar Winther ‡

 * Norwegian Institute for Nature Research, Polar Environmental Centre, Tromsø† Institute of Biology, University of Tromsø‡ Norwegian Polar Institute, Tromsø Microtus voles and lemmings are functionally important species in most terrestrial Arctic ecosystems: they are both prey and predators (herbivores), and are the hosts of many parasites. The key role of these small mammals is primarily due to their population dynamics with recurrent years with high numbers/biomass. Population dynamics patterns and consequently their function in the ecosystem vary geographically and temporally. It has been suggested that such large-scale and long-term patterns are at least in part due to winter climate through properties of the snow cover. However, the links between population dynamics patterns in arctic small mammals and qualitative and quantitative characteristics of the snow cover, as determined by primary climatic variables such as temperature, precipitation and wind, have yet to be established. The project started in 2002 in order to elucidate such links and to predict how climate change may affect the ecosystem functions of arctic small mammals through the properties of ice and snow. For this purpose we study a closed metapopulation of the sibling vole Microtus rossiameridionalis at Svalbard and its interactions with a predator, the arctic fox, and a parasite, the tape-worm Echinococcus multilocularis. The parasite has both the vole (intermediate) and

the fox (final) as host species. This predator-prey/host-parasite system has many favourable model system characteristics that should enable us to establish:(1)    How the variability of winter climate determines qualitative/quantitative properties of the snow

cover in space and time,(2)    How properties of the snow cover in turn shape the spatio-temporal density dynamics in the vole

populations,(3)     How the spatio-temporal variation in vole dynamics and the snow cover in turn shapes the

functional response of the arctic fox to their vole prey, and(4)    Finally, how this chain of processes (1-3) determines spatially and temporally varying prevalence

of Echinococcus multilocularis both in its intermediate (i.e. the vole) and final host (i.e. the arctic fox).

Effects of climatic change on the spruce bark beetle, an economically

important forest pest

Bjørn Økland, Paal Krokene og Erik Christiansen, alle ved Skogforsk i Ås

The spruce bark beetle (Ips typographus) is by far the most serious insect pest on mature

spruce in Eurasia. Studies of how various climate change scenarios may affect its population

dynamics have shown good progress during the first project year. A large-scaled time series

analysis revealed a dominance of lag 1 density dependence, and a marked shift in population

dynamics after a large-scaled windfall episode. These results indicate that the population

dynamics of the spruce bark are determined by resource availability rather than parasite-host

interactions. A strong regional synchrony in spatio-temporal analysis also indicates that some

large-scale climatic factor influence the dynamics. Among different climatic variables tested,

windfelling was the external variable showing the most parallel pattern of spatio-temporal

correlation to beetle dynamics. Thus, large windfall events may be a major synchronizer of

beetle outbreaks in areas subjected to regionalized weather systems, which may override

temperature and drought. The results are now used in the development of a resource-based

model that can be used to extrapolate to alternate climatic scenarios of the future. Test runs of

the model agree with historical data for length of outbreak periods and intervals between

outbreaks. A second model that is under construction sets the number of generations per year

as a function of local temperature, and attempts to predict the geographical distribution of

bivoltism in Norway under climatic change. Two papers from the project have been accepted

for publication in international journals.

Meridional Overturning Exchange with the Nordic Seas

MOEN (ASOF-EU-E)

By

Svein ØsterhusThe mild climate of north western Europe is, to a large extent, governed by the influx of warm Atlantic water to the Nordic Seas. Model simulations predict that this influx and the return of flow of cold deep water to the Atlantic may weaken as a consequence of global warming. MOEN (http://www.bjerknes.uib.no/research/MOEN/) will assess the effect of anthropogenic climate change on the Meridional Overturning Circulation by monitoring the flux exchanges between the North Atlantic and the Nordic Seas and by assessing its present and past variability in relation to the atmospheric and thermohaline forcing. This information will be used to improve predictions of regional and global climate changes. MOEN is a self-contained project of the intercontinental Arctic-Subarctic Ocean Flux (ASOF,http://asof.npolar.no) Array for European Climate project, which aims at monitoring and understanding the oceanic fluxes of heat, salt and freshwater at high northern latitudes and their effect on global ocean circulation and climate.

MOEN will contribute to a better long-term observing system to monitor the exchanges between the North Atlantic and the Nordic Seas from direct and continuous measurements in order to allow an assessment of the effect of anthropogenic climate change on the Meridional Overturning Circulation. This we will be done by measuring and modelling fluxes and characteristics of total Atlantic inflow to the Nordic Seas and of the Iceland-Scotland component of the overflow from the Nordic Seas to the Atlantic.

MOEN objectives: To contribute to a better long-term observing system to monitor the exchanges

between the North Atlantic and the Nordic Seas. To assess the effect of anthropogenic climate change on the Meridional Overturning

Circulation MOEN Tasks:

Measure the total flux and characteristic of Atlantic water passing into the Nordic Seas across the Greenland- Scotland Ridge

Measure the flux and characteristic of the eastern component of the overflows from the Nordic Seas to the North-Atlantic

Estimate the contribution of meso- and small scale processes to these fluxes Model the fluxes and reconstruct their variability since the onset of the 20th century To relate strengths and variability of the fluxes to local and remote forcing

mechanisms as well as to internal modes of oscillations

The Ocean beneath the Ronne Ice Shelf, Antarctica.Svein Østerhus

Early in the history of modern oceanography it was realised that the bottom waters occupying the abyss of the world oceans were renewed from sources at high latitudes. In the north these sources were located in the Nordic Seas and in the south they were traced back to the Weddell Sea. The formation processes for the coldest source water are connected with the Filchner-Ronne Ice Shelf in the southern Weddell Sea. This is a large floating glacier comparable in area to the North Sea and with a thickness ranging from 300 m at the seaward edge (the barrier) to more than 2000 m where it initially goes afloat at its southern boundary. The water mass characteristics in front of the ice shelf are determinded by advection and local modification due to interaction with the atmosphere by heat and freshwater exchange, as well as by freezing and melting of sea ice. Under the ice shelf melting and refreezing at the ice-ocean interface cause further modifications. These natural conditions are unique to the region and result in the formation of large quantities of extremely cold sea water. This poster contain results from the recent years of investigations in the sea water beneath the Ronne Ice Shelf

Transport of mass and heat from the North Atlantic toward the Nordic Seas and the Arctic Ocean.

Svein Østerhus, Bjerknessenteret

The flow of Atlantic water towards the Arctic crosses the Greenland-Scotland Ridge in three current branches. By the heat that it carries along, it keeps the subarctic regions abnormally warm and by its import of salt, it helps maintain a high salinity and hence high density in the surface waters as a precondition for thermohaline ventilation. In mid 1990’s an extensive monitoring program for all three branches was lunched as a Nordic contribution to WOCE and is still going on. The western branch, the Irminger Current, has been monitored by means of traditional current meters moorings on a section crossing the current northwest of Iceland. A number of ADCPs have been moored on a section going north from the Faroes, crossing the Faroes Current. The eastern branch, the Continental Slope Current, is monitored by ADCPs moorings across the Faroe-Shetland Channel. CTD observations from research vessels along all the current meter sections are obtained on seasonal basis. Here we present results from all the branches and offer numbers for the Atlantic water transport and present new tools for cost efficient monitoring of the currents.

Dynamical downscaling of marine climate

Bjørn Ådlandsvik and W. Paul Budgell,Institute of Marine Research

To study the climate effects on economically important activities such as petroleum, fisheries, and aquaculture high quality future climate scenarios are needed. In RegClim we will provide such scenarios by dynamical downscaling from larger scale coupled ocean-atmosphere models. This will be done by forcing a high resolution regional ocean circulation model with results from the large scale couples model at the surface and the lateral boundaries.

The model tool chosen in the Regional Ocean Model System (ROMS). This model uses a terrain-following vertical coordinate. As an adaption to the downscaling use for Norwegian Waters, we have implemented a dynamic-thermodynamic sea ice model and the FRS boundary condition for the lateral boundaries.

Preliminary results will be presented where ROMS has been forced by the NCAR/NCEP reanalysis at the surface and climatology laterally. In particular, a 50+ year hindcast simulation has been performed for the North Atlantic Ocean. Results with finer resolution for the North Sea and the Barents Sea is also presented.