DAOS report to WWRP/JSC

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DAOS report to WWRP/JSC 21-25 Feb 2011 Roger Saunders and Pierre Gauthier

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DAOS report to WWRP/JSC. 21-25 Feb 2011 Roger Saunders and Pierre Gauthier. Overview of DAOS report to JSC Roger Saunders and Pierre Gauthier. WG Activities Update on observations for global NWP Update on developments in DA Results from THORPEX campaigns Paper on targeted observations. - PowerPoint PPT Presentation

Transcript of DAOS report to WWRP/JSC

Page 1: DAOS report to WWRP/JSC

DAOS report to WWRP/JSC

21-25 Feb 2011

Roger Saunders and Pierre Gauthier

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Overview of DAOS report to JSCOverview of DAOS report to JSCRoger Saunders and Pierre GauthierRoger Saunders and Pierre Gauthier

• WG Activities

• Update on observations for global NWP

• Update on developments in DA

• Results from THORPEX campaigns

• Paper on targeted observations

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Mission statementThe DAOS-WG was established to ensure that THORPEX

contributes to the international efforts to optimise the use of the current Global Observing System and to the development of well-founded strategies for the evolution of the GOS to support NWP primarily for 1 to 14 day weather forecasting.

To achieve its mission the DAOS WG, in collaboration with the CBS OPAG-IOS:

• Addresses Data Assimilation issues including the development of improved understanding of the sources and growth of errors in analyses and forecasts

• Promotes research activities that lead to a better use of observations and the understanding of their value

• Provides input and guidance for THORPEX regional campaigns for the deployment of observations to achieve scientific objectives.

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Current membershipPierre Gauthier, Co-chair

UQAM, Canada

Roger Saunders, Co-chair

Met Office, UK

Carla CardinaliECMWF

Ron Gelaro, NASA, USA

Tom HamillNOAA, USA

Tom KeenanCAWCR, Australia

Rolf LanglandNRL, USA

Bertrand Calpini MeteoSwiss, Switzerland

Andrew LorencMetOffice, UK

Florence RabierMétéo-France

Prof. Bin Wang, Chinese Academy of Sciences, China

Michael TsyroulnikovHydroMet Centre, Russia

Chris VeldenUniv Wisconsin-CIMSS, USA

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3rd THORPEX DAOS Working Group meeting

Université du Québec à Montréal8-9 July 2010

Montréal (Québec) CANADA*http://web.sca.uqam.ca/~wgne/DAOS/DAOS3_meeting/

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Update on ObservationsUpdate on Observations• E-AMDAR coverage expanding and now water vapour• Use of IASI radiances over cloud shown to be beneficial• Chinese FY-3A MW sounder radiances proven for NWP• Reduced thinning of AMSU-A radiances at ECMWF• Use of Hi-RES AMVs for improved TC forecasts• Continuity of scatterometer (Oceansat-2?) and GPS-RO

data (COSMIC-2) looks hopeful• Polar Communications and Weather Mission in a Molniya

orbit for improved coverage of the northern polar latitudes.• Raman lidar shows vertical profiles of water vapour at very

high time and vertical resolution and can be available 24 hrs a day for high resolution mesoscale models.

• Common data format for radar backscatter measurements

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E-AMDAR: Network Performance 1.

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E-AMDAR: Network Performance 2.

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E-AMDAR: Network Developments 1.

• 1st Nov 2010 - EZY fleets providing data over UK domain and selected European airports.• Software installed on BAW A319 (LCY – SNN – JFK).

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E-AMDAR: WVSS Programme 1.

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US (NOAA): WVSS Programme 1.

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PCW

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AMVs for Sinlaku in NCEP data file for assimilation (CTL)

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CTL: NCEP cloud windsCTL: NCEP cloud windsCIMSS-6h: CIMSS 6-hourly windCIMSS-6h: CIMSS 6-hourly wind

Enhanced AMVs from CIMSS

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Track and Intensity Analyses for Sinlaku (32 members)

Enhanced AMVs: Significant improvement in analyzed position, track and intensity in first 3 days

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This plot shows the density of AMSU-A channel 9 data for the case of 2008/12/14@00UTC for the different experiments:

• EXP-HI: global thinning to 0.625o

• EXP: global thinning to 1.25o (i.e. ope)• EXP-SV: EXP but with SV thinning 0.625o

• EXP-CLI:EXP but with SVcli thinning 0.625o

• EXP-RND: EXP but with random thinning 0.625o

• Target areas occupy same fraction (15%) of the Southern hemisphere. The SV-based climatology was derived from the mean 2007 SV-areas

Experiments have been run for JAS08 and D08JF09 Forecasts from these experiments have been verified against EXP-HI analyses (~83 cases per season

AMSU-A thinning experimentsEXP-HI

EXP

EXP-SV

EXP-CLI

EXP-RND

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Update on Data AssimilationUpdate on Data Assimilation• Higher resolution reduced thinning

• Observability of structure functions

• Move to hybrid 4D-Var systems

• EnKF systems also being trialled

• Improved background error statistics are key to make better use of humidity observations

• Adjoint sensitivity tools now implemented at most global NWP centres. What about regional/mesoscale?

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Campaigns sponsored by THORPEX

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Concordiasi: an international projectParticipating Institutes:CNES, CNRS/INSU (LMD, LGGE, LA), Météo-France, NSF, AlfredWegener Institute, Met Office, Purdue University, UCAR,University of Colorado, University of Wyoming, BSRNPolar institutes: IPEV, PNRA, USAP, BAS, ECMWFCollaborating institutes:NWP centres (Australia…), NASA/GMAO, UCLA, ….

Part of the THORPEX-cluster

Overview of Concordiasi: “The Concordiasi project in Antarctica”Rabier et al, Bulletin of the American Meteorological Society, January 2010. Website: www.cnrm.meteo.fr/concordiasi/

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CONCORDIASI

• In September and October 2010, 19 balloons were deployed from McMurdo, 6 with a scientific payload sounding the stratosphere, and 13 of the driftsonde type. From the 13 driftsondes, around 640 dropsondes were dropped over Antarctica and the surrounding seas. Most of these were transmitted in real-time on the Global Telecommunication System, for use by the Numerical Weather Prediction centres.

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Balloon tracks

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Dropsonde coverage

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Concordiasi: Sep 2010 Dropsonde Data

• 39 reports up to 21Z 30/9/2010

• 37 assimilated.• Wind: Similar

bias/rms to Antarctic sondes.

• Temp: ~+0.5 K bias above 600hPa. ~-1.0K bias near surface (few reports rejected).

• Humidity: 11/37 reports rejected. Not RS92 so data <-40C not used.

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Assimilation of surface sensitive observations from AMSU over land: Impact on humidity analyses

Impact studies with 2 versions of ARPEGE: CY32 and CY33 during summer 2006. CY33 introduces important changes in the physics. Data assimilation is identical between the two versions and takes advantage of better description of the land surface emissivity to assimilate the observations near the surface (Karbou et al. 2006-2010ab).

TCWV (EXP-CTL), CY32, August 2006

TCWV (EXP-CTL), CY33, August 2006

Similar humidity bias features were noticed with the assimilation of MERIS observations over land (Bauer, 2009) and AMSU observations in IFS

More moisture in EXPF. Karbou

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HyMeX: 2 types of balloons will be used in 2012-2013BAMED project (CNES)

Alex Doerenbecher, Clement Fesquet, Claude Basdevant

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The intercomparison experiment on the impact of observations

A goal of THORPEX is to improve our understanding of the ‘value’ of observations provided by the current global network

In 2007, DAOS-WG proposed a comparison of observation impacts in several forecast systems, facilitated by the emergence of new (adjoint-based) techniques

Experiments for a baseline observation set were designed by DAOS members from NRL, GMAO, EC, ECMWF, Météo-France …so far, results obtained for 3 systems: NRL, EC, GMAO

• optimize the use of current observations• inform the design/deployment of new obs systems

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AMSU-A, Raob, Satwind and Aircraft have largest impact in all systems

GMAO GEOS-5NRL NOGAPS

EC GDPS

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Global domain: 00+06 UTC assimilations Jan 2007

Daily average observation impacts

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24h Observation Impacts in GEOS-5Average values at 00z for the period 01 Sep – 31 Dec 2010

Global Northern Hemisphere

TropicsSouthern Hemisphere

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Total # of targeted radiosonde data = 27,508 (06UTC and 18UTC)

Number of targeted radiosonde profiles = 247 (33 stations provided at least one profile)

Total targeted radiosonde impact = -0.4322 J kg-1

For comparison: 00UTC and 12UTC observations from these same stations: -4.24 J kg -1 and 2,154 profiles during all of January 2009

1x10-3 J kg-1 (Moist Total Energy Norm)

Error Reduction Error Increase

Circled stations provided ten or more profiles

JANUARY 2009

Petropavlosk

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FEBRUARY 2009TARGETED DROPSONDE IMPACT ON 24H FORECAST ERROR IN NOGAPS/NAVDAS

1x10-3 J kg-1 (Moist Total Energy Norm)

Error Reduction Error Increase

Total # of assimilated dropsonde data = 32,172 (T, q, u, v at all levels)

Number of dropsonde profiles = 355

Total dropsonde impact = -0.7176 J kg-1

Average impact per dropsonde observation = -2.23x10-5 J kg-1

Impact summed in 2x2 lat/lon boxes

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1x10-3 J kg-1 (Moist Total Energy Norm)

Error Reduction Error Increase

Impact summed in 2x2 lat/lon boxes

January 2009 – all analysis times

EAMDAR Summary Impact #of observations

Level Flight - 3.618 J kg-1 337,506 + 3% from Dec 2008

Ascent Profiles - 1.891 J kg-1 79,850 + 19% from Dec 2008

Descent Profiles -1.003 J kg-1 33,301 + 64% from Dec 2008

ALL Lufthansa AMDAR

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Summary of intercomparison Comparison experiments for GMAO, NRL and EC systems completed for

baseline set of observations and now UKMO added Despite differences in assimilation methodologies, overall quantitative

results similar for all systems; but details of impact differ (e.g., impact-per-ob, channels)

Largest impacts provided by AMSU-A and raobs (GMAO, UKMO), AMSU-A and satwinds (NRL, EC); aircraft also has large impact in all systems

Common problem areas with AMSU-A noted; handling of surface properties a likely cause

First paper of adjoint impact intercomparison facilitated by DAOS WG has been published (Gelaro et al. 2010)

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DAOS-WG draft statement on need DAOS-WG draft statement on need for additional in-situ observationsfor additional in-situ observations

There is increasing evidence based upon results from A-TREC, TPARC, AMMA (in the form of OSEs, adjoint-based observation impact studies, and analysis uncertainty estimates) to recommend, if feasible, increases in observations from:

• Commercial aircraft over the N. Pacific, N. Atlantic, and the S. Hemisphere in general.

• Additional soundings from certain coastal radiosondes, including those in eastern Siberia, and perhaps selected stations in polar regions, Africa, and South America.  

to improve NWP forecasts in the 2-5 day timeframe.

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Review of the impact of targeted data

• Community paper being written

* Lead author is Sharan Majumdar with contributions from the DAOS-WG and scientists involved in targeting campaigns (including Y. Song and Z. Toth)

• Reconcile seemingly opposing views on the impact of targeted data

* Summary of results obtained so far

* Identify issues that need to be addressed to improve the use of observations that impact weather forecasts (e.g., metrics, assimilation methods, sampling of precursors to dynamic instability)

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A. Doerenbecher, Météo France

The targeting

procedure

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Field Campaigns: pre-THORPEX / independent campaigns

• 1997: FASTEX• 1998: NORPEX• 1999-present: NOAA

Winter Storm Reconnaissance (WSR)

• 1982-96: NOAA Hurricane Synoptic Flow

• 1997-present: NOAA Hurricane Synoptic Surveillance

• 2003-present: DOTSTAR Typhoon Surveillance

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Field Campaigns: THORPEX era

• 2003: A-TReC. Atlantic, minimal impact.(Forecasts very good without targeted obs)

• 2006-9: European Experiments with a small targeting component: AMMA-THORPEX, COPS/E-TReC, GFDex, DTS-MEDEX, THORPEX-IPY

• 2008: Summer T-PARC• 2009: Winter T-PARC• 2010 and future: Concordiasi, HYMEX, T-

NAWDEX (THORPEX PDP)EURORISK PREVIEW helped facilitate coordination

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Winter T-PARC case

Y. Song, NOAA/NCEP

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24 36 48 60 72 84 96 108 1200

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forecast lead time (h)24 36 48 60 72 84 96 108 120

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GFS typhoon forecasts, lead time: 24-120 h

GFS NoDrop

GFS Drop

NCEP GFS

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WRF NoDrop

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JMA Dropno mean improvement?

JMA GSM

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ECMWF and GFS typhoon forecasts, lead time: 24-120 h

EC NoDrop

EC Drop

ECMWF

improvement after 72 h

Period: 2008090900-2008091812 and 2008092412-2008092900

track error reduced by up to 200km!

Summer T-PARC: effectiveness of targeted obs depends on model/DA

M. Weissmann, DLR

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Conclusions 1

• Extratropical: average value of targeted data (mostly from aircraft) is positive but small.– Still a lack of strong consensus, limited evaluations– Results may depend on choice of verification metric

• Tropical cyclones: significant benefits sampling around the storm; results depend on model.

• Most evaluations for short-range (1-3 day) forecasts. Smaller sample for medium-range; results promising in some cases, neutral in others.

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Conclusions 2• Targeting techniques that identify ‘sensitive’ areas

sometimes agree, sometimes disagree, but are not thought to be the first-order problem.– Targeting in sensitive areas is better than at random

– Target areas are often in cloudy areas and/or baroclinic zones

• Results from the adjoint-based observation impact calculations can be used to explain why we cannot consistently get large impacts from a few targeted observations.– Benefit of aircraft data per observation is large, but

cumulative benefit is small.

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Recommendations• Seek to further optimize existing resources: commercial

aircraft, rawinsonde network, satellite radiances, atmospheric motion vectors

• Account for data assimilation scheme in targeting strategy; quantitatively predict effects of obs

• Further evaluations with common cases and multiple models/DA would strengthen conclusions

• Targeting for longer-range f/casts is interesting topic, but results are not mature enough to make an authoritative statement. Broader-scale regime-based targeting seems the most promising approach.

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Targeted Observations for Improving Numerical Weather

Prediction: An OverviewS. J. Majumdar (RSMAS/U. Miami)

R. Saunders, P. Gauthier (DAOS WG Co-Chairs)S. Aberson, C. Bishop, C. Cardinali, J. Caughey, A.

Doerenbecher, R. Gelaro, T. Hamill, R. Langland, A. Lorenc, T. Nakazawa, F. Rabier, C. Reynolds, Y. Song, Z. Toth, C. Velden, M. Weissmann, C.-C. Wu plus contributions from

past and present DAOS WG membersManuscript in preparation for WMO Report and BAMS