THOR

Presented by Doug Smith (MET OFFICE)Project coordinator: Detlef Quadfasel (UHAM)

www.eu-thor.euTHOR.EU@zmaw.de

Arctic Ice Cover during Winter

3000 km

< 1000 km

Winter ice boundaries

Population in the North

~ 400 Mio

~ 40 Mio

~ 4 Mio

Seasonal Ice Cover

Decadal Variability - Trends

?

Ocean Circulation carries Heat to the North

… and returns fresh water south

Shallow Circulation

Deep Circulation

North Atlantic Thermohaline Ocean Circulation and its Impact on Climate: Thermohaline Overturning – at Risk ?

Facts and Figures

FP 7 Collaborative Project – Large Scale

Project lifetime: 4 years, December 2008 – November 2012

Research focus: Stability of the ThermoHaline Circulation

Participants: 20 participating institutions from 9 European countries

5 Core Themes, 12 Work Packages

Project cost: 12.95 million Euro

EU Funding: 9.27 million Euro

Core Theme 1MOC Variability

Core Theme 3 Observations

Core Theme 2Model Uncertainty

Core Theme 5Technological Advancements

Core Theme 4Prediction & Predictability

What is it all about? THOR and its 5 core themes

NADW – North Atlantic Deep Water1 Sv = 106 m3/s

Project Management and Coordination (UHAM)

CT 1: Quantifying and modelling THC variability using palaeoclimate observations and simulations (MPI-M, MetO, UPMC, UiB, IFM-GEOMAR, NERSC, CNRS)

CT 2: Assessing sources of uncertainty in ocean analyses and forecasts(DMI, MPI-M, MetO, UPMC, UiB, IFM-GEOMAR, NERSC)

CT 3: Observations of the North Atlantic THC(UiB, UHAM, IFM-GEOMAR, HAV, MRI, NIOZ, NERC, SAMS, MPI-M)

CT 4: Predictability of the Meridional Overturning Circulation(KNMI, MPI-M, MetO, ECMWF, UREAD, IFM-GEOMAR)

CT 5: Technological Advancements for Improved near-real-time data transmission and Coupled Ocean-Atmosphere Data Assimilation (IFM-GEOMAR, UHAM, UiB, NERC, ECMWF, KNMI)

Gov

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International Advisory P

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Gender P

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Project Structure

Core Theme 1: Understanding Variability

Analysis of Millennium-scale numerical experiments and paleo-records

Atlantic inflow into the Nordic Seas

The observations and the model simulation show predominantly multidecadal-scale variability and a similar long-term evolution

Otterå, Bentsen, Drange & Suo, 2010

Core Theme 1: On-going Work

The figure shows how the vigor of Iceland-Scotland Overflow Water (ISOW) (, in red) (Mjell et al. in prep) and basin wide temperature (AMO in blue, after Gray et al., 2004) have co-varied over the past 400 years.

i.e. Relation between newly observed overflow strength and the basin-wide temperature changes:

Core Theme 2: Assessing Model Uncertainties

i.e. melting of the Greenland Ice Sheet, impact on the Ocean fresh water – salinity distribution after 30 years

Input of 0.1 Sv around Greenlandeast & west

west only

east only

Biastoch, 2010

Ocean reanalyses and observations, sensitivity experiments

Core Theme 2: On-going Work

Passive tracer release along the coast of Greenland

Working hypothesis: The effect of additional runoff on the convective activity in the interior Labrador Sea is weaker in models which resolves eddies. Coarser resolution models applying parameterizations which tend to cap the area with freshwater from the sides

After 3.5 years

Collapse of convection in the LS

The coarse simulation is less effected by additional freshwater due to lower initial overturning and lack of initial deep convection in the Labrador Sea

Core Theme 2: On-going Work

Core Theme 3: Observing the AMOC

Volume transport for deep western boundary current at the exit of the Labrador Sea (1997-2009);J. Fischer (IFM-GEOMAR)

Heat content of central Labrador Sea from K1 T time series (1997-2009);J. Fischer (IFM-GEOMAR)

Volume fluxes of MOC and mooring profiles of T,S at 26.50N (2004 - ongoing); S. Cunningham (NOCS/NERC)

Volume fluxes of FBC overflow (1995-2010), IFR inflow (1997-2010) and CTD standard sections;B. Hansen (FFL)

Volume fluxes of inflow of Atlantic waters in FSC (1994-2008), overflows at FSC and WTR (2003-2008) and CTD standard sections ; T. Sherwin (SAMS)

Volume transport of DSOW from Angmag-ssalik array and T,S time series (1994-2009);D. Quadfasel (IFM-UHAM),S. Dye (CEFAS)

Volume fluxes and T,S time series for Central Irminger Sea (2002-2009);J. Fischer and J. Karstensen (IFM-GEOMAR)

Volume fluxes in the IrmingerSea and CTD sectionsBetween Greenland andIreland (2003-2008);H. van Aken (NIOZ)

1/1/04 1/1/05 1/1/06 1/1/07Da te

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21 0 m28 90 m

Volume and heat fluxes of Atlantic waters at Hornbanki section (1994-2009);S. Jónsson (MRI)

Transport data setsHydrography data sets

Datasets regularly updated, accessible through project homepage

Volume transport of DSOW and EGC at Denmark Strait sill section (1995-2011);D. Quadfasel (IFM-UHAM)

Core Theme 4: Prediction and Predictability

+

Data

Model

Synthesis

=

Hindcasts – ocean only Forecasts

initialisatio

n

PREDICATE: Sutton, 2004Köhl pers. con. 2010

Core Theme 4: On-going work – your input?

Core Theme 5: Technological Advancements

Real true data transmission from moorings: the Bergen and Kiel system

Data assimilation in coupled models: THOR

Core Theme 5: On-going

1. Real true data transmission from moorings

The Bergen System (accomplished)

Core Theme 5: On-going

1. Real true data transmission from moorings

The Kiel System (testing)

Core Theme 5: On-going

2. Data assimilation in THOR coupled model

• coupling: replacement of seaice- and ocean- compartments of the PlanetSimulator by MITogcm plus seaice

• configuration: coarse resolution setup with an atmosphere on a T21 grid and 5 sigma levels, and the MITogcm on a 5.625º grid having the North Pole shifted to Greenland, using 15 vertical levels

• testing: coupled system with single CPU on a notebook, performance is approx. 30 model years/day