SMOS SOIL MOISTUREPRODUCT EVALUATIONOVER VARIOUS SITESClaire Gruhier, Arnaud Mialon, Silvia Juglea,Ahmad Albitar, Simone B...
IntroductionSoil Moisture and Ocean SalinityPassive microwaves sensor in L-bandLaunched the 2th November 2009Global soil m...
Denmark                           HOBELocationSkjern River CatchmentMeasurementsAirborne campaign EMIRAD (L-band, HV)4 fli...
Denmark                                           HOBE  Airborne campaign: TB comparison over spatial scales              ...
Denmark                           HOBE     Comparison SM values at pixel scale     > Retrieved L2SM product and network   ...
South of France                                        SMOSREXLocationNear Toulouse (Mauzac, ONERA site) 43°23 N ; 1°17 EM...
South of France                                                SMOSREX    Comparison SM values                            ...
East of Spain                                   VASLocationUtiel-Requena PlateauValencia, Spain, 39°34’15’’N, 1°17’18’’WMe...
East of Spain                    VASComparison of TB simulated with L1C product> Soil moisture is spatialisedwith SURFEX m...
East of Spain                               VASComparison SM values at pixel scale  > L2SM values are lower than those mod...
West Africa                                         AMMALocationNiger and BeninMeasurementsSoil moisture/temperature netwo...
West Africa                            AMMAComparison SM values over Niger site> Comparison to weighted averagedof in-situ...
West Africa                AMMAComparison SM values over Benin site> Same trend> RMSE higerthan over Nigerbecause ofvariab...
East of AustraliaLocation                                       AACESAustralia, Murrumbidgee CatchmentMeasurementsAirborne...
East of Australia                         AACESComparison SM values> SMOS L2SM closer from in-situ valuesthan initial valu...
East of Australia                         AACESComparison SM values> SMOS L2SM closer from in-situ valuesthan initial valu...
USA             SCANLocationUnited States of AmericaMeasurements235 permanent soil moisture stationsEnvironmental conditio...
USA             SCANComparison SM values> Same trend can beobserved between both soilmoisture series> Tau values are quest...
USA             SCANComplete comparison               Correlation       Correlation                                 all si...
Conclusion> L2SM product based on V4 algorithm clearly improved the accuracy of                                           ...
SMOS           SOILMOISTURE PRODUCTEVALUATION    OVERVARIOUS SITESClaire Gruhier, Arnaud Mialon, SilviaJuglea,Ahmad Albita...
Upcoming SlideShare
Loading in...5
×

MO3.T03_3399_GRUHIER.pdf

417

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
417
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
13
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

MO3.T03_3399_GRUHIER.pdf

  1. 1. SMOS SOIL MOISTUREPRODUCT EVALUATIONOVER VARIOUS SITESClaire Gruhier, Arnaud Mialon, Silvia Juglea,Ahmad Albitar, Simone Bircher,Thierry Pellarin, Yann KerrCESBIO, Toulouse, FranceDTU Space, Copenhagen, DenmarkLTHE, Grenoble, FranceIGARSS 2011-8283 | HS6.2 | Monday 25 July 2011 | Vancouver, Canada
  2. 2. IntroductionSoil Moisture and Ocean SalinityPassive microwaves sensor in L-bandLaunched the 2th November 2009Global soil moisture product every 3 daysIn the context of the CAL/VAL of SMOS missionEvaluation of SMOS soil moisture productallows us to improve algorithm and finally productCAL/VAL over various sites around the worldA lot of sites was chosen to conduct CAL/VAL activitiesIn this study : 6 sitesDenmark HOBE Hydrologycal ObservatorySouth of France SMOSREX Surface Monitoring Of Soil Reservoir EXperimentEast of Spain VAS Valencia Anchor StationWest Africa AMMA African Monsoon Multidisciplinary AnalysesEast of Australia AACES Australian Airborne Cal/Val Experiment for SMOSUSA SCAN Soil Climate Analysis Network
  3. 3. Denmark HOBELocationSkjern River CatchmentMeasurementsAirborne campaign EMIRAD (L-band, HV)4 flights & ground sampling, 26 april to 9 may 201030 stations within SMOS ”pixel”, since Dec 2009Environmental conditionsClimate : Temperate-maritimeLand cover : Crop 78%, Forest 14%, Heath 6%Soil : sandyS. Bircher et al, "A soilmoisture network for SMOSvalidation in the Skjern RiverCatchment, WesternDenmark", in prep.S. Bircher,et al, "SMOSValidation by means of anairborne campaign in theSkjern River Catchment,Western Denmark",submitted to TGRSS, SMOSSpecial Issue (under revision).Simone Bircher, DTU
  4. 4. Denmark HOBE Airborne campaign: TB comparison over spatial scales Model ground (L-MEB) vs EMIRAD EMIRAD avg vs SMOS L1C HV 2x2 km patch scale 44x44 km SMOS ”pixel” scale 300 May 2, 2010 04:15 UTCGROUND TB (K) H_0 H_40 280 260 TB (K) 240 270 220 V_0 V_40GROUND TB 200 245 Crop 180 EMIRAD V EMIRAD H Heath x SMOS V x SMOS H(K) Forest 160 220 245 270 0 10 20 30 40 50 60 70 EMIRAD TB [K] EMIRAD TB [K] Ө°Able to reproduce EMIRAD Good accordance between RMSE (K)measurements by means of modeled EMIRAD and SMOS TBs 0° 40°TBs from ground data on all 4 Other campaign days too H 7.74 9.33campaign days, for all patch types RFI-prone for comparison.. V 8.30 5.58Simone Bircher, DTU
  5. 5. Denmark HOBE Comparison SM values at pixel scale > Retrieved L2SM product and network 0.30 In situ values (m3/m3) soil moisture show the same trend > Retrieved SMOS SM exhibits higher 0.20 amplitudes and a distinct negative bias compared to the ground data 0.10 R = 0.7 RMSE = 0.096 Bias = 0.086 0.0 0.10 0.20 0.30 L2SM (m3/m3) 0.35SM (m3/m3) 0.0 Jan 10 Mar May Jul Sep Nov Jan 11 Simone Bircher, DTU
  6. 6. South of France SMOSREXLocationNear Toulouse (Mauzac, ONERA site) 43°23 N ; 1°17 EMeasurementsLEWIS L-band radiometer (HV), since 2003Ө = 20°, 30°, 40°, 50 °, 60°Soil moisture/temperature network, 2 stations, since2003Environmental conditionsClimate : TemperateLand cover : Bare soiland GrasslandSoil : 16% clay, 36% sandArnaud Mialon, CESBIO
  7. 7. South of France SMOSREX Comparison SM values SMOS vs In situ > The same trend can be observed January to May 2011 between L2SM product and the station Bare soil Grassland > L2SM values are closer to in situ R 0.64 0.58 values on bare soil in term of absolute RMSE 0.076 0.208 values and dynamic Bias -0.051 -0.1990.5 0.5 L2SM (m3/m3)SM (m3/m3)0.0 Jan 10 Fev Mar Apr May 0.0 0.5 In situ (m3/m3) Arnaud Mialon, CESBIO
  8. 8. East of Spain VASLocationUtiel-Requena PlateauValencia, Spain, 39°34’15’’N, 1°17’18’’WMeasurementsSoil moisture/temperature network,6 stations, since 2007Environmental conditionsClimate : semiarid and dry-sub-humidLand cover : vineyard crops, olive and almond trees surrounded by pine and Mediterranean forests.Soil : sand 125x125 km² 50x50 km² 10 km 10 km SMOS pixel 50 km size 125 km 50 km 10x10 km² 125 km control areaSilvia Juglea, CNES/CESBIO
  9. 9. East of Spain VASComparison of TB simulated with L1C product> Soil moisture is spatialisedwith SURFEX modelTB are modeled with L-MEB> The temporal variations ofTBhv SMOS is in goodagreement with the TBmodelon VAS, but TB from SMOS aretoo high> The parameterization of theradiative transfert modelmust be reconsidered to takeinto account all thecharacteritics of the VAS area TB SMOS vs TB VAS H V R2 0.51 0.42 RMSE 16.24 20.82 Bias 0.02 14.72Silvia Juglea, CNES/CESBIO
  10. 10. East of Spain VASComparison SM values at pixel scale > L2SM values are lower than those modeled by SURFEX (validated with insitu values). This underestimation can be explained by too high SMOS TB (could be explained by RFI) SM in-situ vs L2SM July to November 2010 18h 6h DES ASCR2 0.59 0.54RMSE 0.109 0.085Bias -0.076 -0.039Silvia Juglea, CNES/CESBIO
  11. 11. West Africa AMMALocationNiger and BeninMeasurementsSoil moisture/temperature network, 6 stationsEnvironmental conditionsClimate : Sahelian / SudaneseLand cover : tiger bush / woody savanna and tropicalforestSoil : sandGruhier C., T. Pellarin, P. de Rosnay, Y Kerr, « SMOS soil moisture .product evaluation over West-Africa at local and regional scale »Claire Gruhier, CESBIO
  12. 12. West Africa AMMAComparison SM values over Niger site> Comparison to weighted averagedof in-situ values according to theirdistance from the DGG selectedHeight = DQXWidth = STD of in-situ measurements> Same trend> RMSE less than 0.04 m3/m3 (Gruhier et al, submitted)Claire Gruhier, CESBIO
  13. 13. West Africa AMMAComparison SM values over Benin site> Same trend> RMSE higerthan over Nigerbecause ofvariability duringrainy seasondue to forestland cover (Gruhier et al, submitted)Claire Gruhier, CESBIO
  14. 14. East of AustraliaLocation AACESAustralia, Murrumbidgee CatchmentMeasurementsAirborne campaign AACES (L-band, HV)January/Feb. 2010 and September 2010Permanent soil moisture stationsEnvironmental conditionsClimate : Semi-aridLand cover : crops and grasslandSoil : sand > see Chris Rugiders talkArnaud Mialon, CESBIO
  15. 15. East of Australia AACESComparison SM values> SMOS L2SM closer from in-situ valuesthan initial values (ECMWF)> In general, SMOS L2SM less than Insitu soil moisture values. Except afterrain events> SMOS sensitive to 0-3 cm top surfacelayer, whereas in situ measurements are0-5 or 0-8 cm surface layerArnaud Mialon, CESBIO
  16. 16. East of Australia AACESComparison SM values> SMOS L2SM closer from in-situ valuesthan initial values (ECMWF)> In general, SMOS L2SM less than Insitu soil moisture values. Except afterrain events> SMOS sensitive to 0-3 cm top surfacelayer, whereas in situ measurements are0-5 or 0-8 cm surface layerArnaud Mialon, CESBIO
  17. 17. USA SCANLocationUnited States of AmericaMeasurements235 permanent soil moisture stationsEnvironmental conditionsClimate : VariousLand cover : Various (Forest, crops, grassland...)Soil : VariousAhmad Albitar, CESBIO
  18. 18. USA SCANComparison SM values> Same trend can beobserved between both soilmoisture series> Tau values are questionable> SMOS captures the drydowns Nb values 230 R 0.77 RMSE 0.065 Bias 0.04Ahmad Albitar, CESBIO
  19. 19. USA SCANComplete comparison Correlation Correlation all sites (235) nominal sites (98)> Nodes with more than 90%of bare soil and lowvegetationSites = 98/235> Good fit across a variety oflocal sites but completeanalysis for all sitesdecreases performances Bias RMSE> SMOS soil moisture is dryer nominal sites nominal casesthan site data (98) (98)reasons : penetrationdepth /measured depth, dataquality, spatial averagingAhmad Albitar, CESBIO
  20. 20. Conclusion> L2SM product based on V4 algorithm clearly improved the accuracy of 8retrieved values and more values are also retrieved (not shown)> Soil moisture variations provided by L2SM V4 product are consistent with in-situ measurements in term of correlation and RMSEThe rainy events are perfectly reproducedThe L-band sensitivity allow us to monitor drying out period> SMOS L2SM product generaly underestimate ground measurements,which can be explained by the depth: In-situ values are recorded at 5cm of depth the penetration depth of SMOS is ~0-3cmby scaling effect and representativity: Local measurement / spatial integrated valuesAnd RFI in some areas> Reduction of RFI source is on the way> Mironov/Dobson models are currently being evaluated to computed theemissivity> Forest modeling is being investigated to improve algorithm for high vegetationoptical depth> … and more> SMOS after 14 months in operation is alearldy giving good reasults but thereis still room for improvements... and we are working on it !
  21. 21. SMOS SOILMOISTURE PRODUCTEVALUATION OVERVARIOUS SITESClaire Gruhier, Arnaud Mialon, SilviaJuglea,Ahmad Albitar, Simone Bircher,Thierry Pellarin, Yann KerrCESBIO, Toulouse, FranceDTU Space, Copenhagen, DenmarkLTHE, Grenoble, FranceIGARSS 2011-8283 | HS6.2 | Monday 25 July 2011 | Vancouver, Canada
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×