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Analysis of AMSR-E C & X-band Tb data dependencies with wind & wave characteristics.

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Presentation on theme: "Analysis of AMSR-E C & X-band Tb data dependencies with wind & wave characteristics."— Presentation transcript:

1 Analysis of AMSR-E C & X-band Tb data dependencies with wind & wave characteristics

2 Questions ? How is Roughness-induced sea surface emissivity in the low frequency microwave domain dependent with sea surface state & wave developement ? Impacts of swell, pure wind seas or mixed sea states on the emissivity at X, C & L -bands? Needs to get sea state parametrization & active/passive roughness effects consistency in the aquarius L-band SSS retrieval algorithm

3 How ? Collect one month (aug 2010) of global L2A AMSR-E Tbs & L2 ocean products (sst, wind, water vapor, …) Evaluate surface emissivity e surf residuals based on Wentz algorithm for atmospheric & external sources corrections Co-locate AMSR-E data with wave parameters (total significant wave height Hs, significant wave height for wind sea Hs ws ) from ECMWF-WAM model forecasts (3-hourly at 0.25° res) and ECMWF U 10 Estimate roughness-induced residuals Δe rough using in situ SSS & AMSRE.SST to evaluate flat sea contribution Look @ statistical depedencies of Δe rough with bins of Hs,U 10 & Hs ws

4 Déploiement, Collecte & Traitement des Données In situ de surface pour la Validation de SMOS Projet GLOSCAL

5 Exemple of the Data set over 1 month @ 25 km resolution Objectively Analyzed Standardized in situ data +climatology LPO

6 Dielectric constant model (Klein & swift, 76) Estimating the Flat sea surface Tbs contributions

7 Estimated monthly mean-averaged Flat sea surface Tbs contributions for X & C, H-V AMSR-E channels

8 Estimated surface Tbs from X & C, H-V AMSR-E data

9 Wind & wave products

10 Co-localisation AMSR-ECMWF: |Δ t|<1.5 Hour & | Δ x|<25 km

11 Estimated monthly-averaged roughness induced emissivity residuals

12 Mean Roughness induced emissivity residuals as function of surface wind speed

13 Mean Roughness induced emissivity residuals as function of surface wind speed & total significant wave-height

14 Selection of data for ECMWF winds 4.5<U10<5.5 m/s Illustration of the Mean Large Scale Wave impact on Roughness induced emissivity residuals at a fixed surface wind speed of ~5 m/s Histograms of Hs for all waves and wind sea at U10~5m/s Wind sea~0.5m swells~0.5-3 m Very distinct distributions The Hs changes at U10~5m/s are dominated by swell impact

15 Selection of data for ECMWF winds 4.5<U10<5.5 m/s Illustration of the Mean Large Scale Wave impact on Roughness induced emissivity residuals at a fixed surface wind speed of ~5 m/s For wind speed ~5 m/s, swells affect surface emissivity at 55° incidence angle and H-pol, have a negligible impact in V-pol

16 Illustration of the Mean Large Scale Wave impact on Roughness induced emissivity residuals at a fixed surface wind speed of ~8 m/s

17 Monthly average signature of tropical freswaterpools in AMSR-E Tbs

18 Monthly average signature of Tropical Atlantic freshwaterpools in AMSR-E Tbs Orrinoco RiverAmazon River Niger River Congo River Senegal & Geba Rivers

19 Mississipi Delta Freshwater runoff into the Tehuantepec Gulf

20 Ganges and Brahmaputra Rivers Irrawaddy Delta Indus Delta

21 Yangtse River


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