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2004/11/10GIST 22, Brussels, LMD, M. Viollier1 POLDER, CERES, GERB flux comparisons and information on AMMA and MeghaTropiques Michel Viollier Laboratoire de Météorologie Dynamique, IPSL/CNRS, Ecole Polytechnique Palaiseau, France with technical support by Sylvain Lassaut
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2004/11/10GIST 22, Brussels, LMD, M. Viollier2 Outline Information: AMMA, Megha-Tropiques CERES, POLDER nadir comparison CERES, GERB flux comparison (January to March 2004) Monthly diurnal cycles from GERB
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2004/11/10GIST 22, Brussels, LMD, M. Viollier3 AMMA (1/3) African Monsoon Multidisciplinary Analyses (http://medias.obs-mip.fr/amma/index.en.html)http://medias.obs-mip.fr/amma/index.en.html multidisciplinary project on the West African Monsoon and its impacts Atmospheric Dynamics, Continental Water Cycle, Atmospheric Chemistry, Oceanic and Continental Surface Conditions. Participation: France, Germany, UK, USA, Africa, … French Agencies: CNES, CNRS/INSU, IRD, and Meteo-France
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2004/11/10GIST 22, Brussels, LMD, M. Viollier4 AMMA (2/3) Long Term Observation Period : … 2009 Special Observing Period (SOP): various key stages of the rainy season during three periods in 2006: (i) monsoon onset, (ii) peak monsoon and (iii) late monsoon AMMA-SAT : the satellite data component of AMMA http://ammasat.lmd.polytechnique.fr/WelcomeE.html In this project : we promote CERES and GERB data and plan to incorporate their main parameters in the AMMA-SAT database
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2004/11/10GIST 22, Brussels, LMD, M. Viollier5 AMMA-SAT (3/3) - data-set with multiple satellite products and data - netcdf format with standard grid, organization and documentation (tools: ferret, live access server) GERB data in AMMA-SAT: - link to GERB archive system? - mirroring the GERB site? - hdf to netcdf transformation (of main parameters)? Amma-sat regions (globe for coarse grid)
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2004/11/10GIST 22, Brussels, LMD, M. Viollier6 ScaRaB-3 on - Tropiques (Megha-Tropiques) Joint project between France and India Stopped last year (CNES budget cuts) New green signal on 2004 End of B phase: 2004 Start of C phase: 2005 Planned to be launched on 2009
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2004/11/10GIST 22, Brussels, LMD, M. Viollier7 Basic Megha-Tropiques Instruments
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2004/11/10GIST 22, Brussels, LMD, M. Viollier8 Megha-Tropiques Orbits
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2004/11/10GIST 22, Brussels, LMD, M. Viollier9 June 2003 – Reflectance vza<20° POLDER minus CERES grid box method (0.5°) (Reflectances multiplied by 100) Narrow-to-Broadband Conversion Validation with CERES.
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2004/11/10GIST 22, Brussels, LMD, M. Viollier10 POLDER-CERES along track and nearest ‘pixel’ method Collocated POLDER triplets and CERES data ( T < 5 mn D <2km) for June 2003 (1, 4, 5, 8, 11, 14, 17, 20, 24, 27, and 30 )
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2004/11/10GIST 22, Brussels, LMD, M. Viollier11 POLDER CERES : radiance and flux comparison at nadir
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2004/11/10GIST 22, Brussels, LMD, M. Viollier12 GERB/CERES flux comparisons - GERB data: ex. G2_SEV1_L20S_20031223_130000_V002.hdf - CERES : ES8 - 3 periods: Jan 1-5, Feb 15-19, Mar 21-25 2004 - average data over 2.5 x 2.5° regions (and also 1° x 1°) - keep regions with more than 80 (CERES) and 20 (GERB) observations for 2.5 x 2.5° regions - compare GERB and CERES flux regional means, coincident ± 2 minutes (however, in the present version, we approximate UTC to the half quarter, i.e. 00:07:30, 00:22:30,.. )
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2004/11/10GIST 22, Brussels, LMD, M. Viollier13 March 2004, 21 - flux CERES 2.5° grid filled with GERB data
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2004/11/10GIST 22, Brussels, LMD, M. Viollier14 GERB-CERES co-registration
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2004/11/10GIST 22, Brussels, LMD, M. Viollier15 Jan. 2004, 1 to 5 – CERES/Terra GERB SWLW dayLW night
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2004/11/10GIST 22, Brussels, LMD, M. Viollier16 stat 2.5 (1.0) degree grid GERB-Terra % mean difference GERB-Aqua % mean difference SWLW day LW night SWLW day LW night Dec 23 1.4-0.57-1.5 Jan 1-5 -3.2 -3.1-2.4 -2.1 -2.4 1.2 0.2 -2.3 -2.6 -2.1 -2.2 Feb 15-20 -1.8 -2.6 -2.2 -2.3 -2.5 -3.2 -2.07 -2.60 -1.9 -2.3 -2.2 -2.4 Mar 21-25 -2.6 -3.6 -1.9 -2.0 -2.5 -2.6 -3.4 -3.2 -1.5 -1.9 -2.2 -2.5 Difference in sampling ?
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2004/11/10GIST 22, Brussels, LMD, M. Viollier17 CERES/GERB flux intercomparison LW dayLW nightSW mean difference < ~2%, (preliminary result for 2003 Dec 23, approximate GERB observation time= 00:07:30, 00:22:30,.. )
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2004/11/10GIST 22, Brussels, LMD, M. Viollier18 Jan. 2004, 1 to 5 – CERES/Aqua GERB SWLW dayLW night
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2004/11/10GIST 22, Brussels, LMD, M. Viollier19 Feb. 2004, 15 to 20 – CERES/Terra GERB SWLW dayLW night
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2004/11/10GIST 22, Brussels, LMD, M. Viollier20 Feb. 2004, 15 to 20 – CERES/Aqua GERB SWLW dayLW night
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2004/11/10GIST 22, Brussels, LMD, M. Viollier21 March 2004, 21 to 25 – CERES/Terra GERB SWLW dayLW night
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2004/11/10GIST 22, Brussels, LMD, M. Viollier22 March 2004, 21 to 25 – CERES/Aqua GERB SWLW dayLW night
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2004/11/10GIST 22, Brussels, LMD, M. Viollier23 Same (March, Aqua) but 1° grid SWLW dayLW night
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2004/11/10GIST 22, Brussels, LMD, M. Viollier24 Diurnal variations using GERB (preliminary) – 2004, January Ocean, clear and partly cloudy
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2004/11/10GIST 22, Brussels, LMD, M. Viollier25 Diurnal variations using GERB (preliminary) – 2004, January Land (S. Africa), clear and partly cloudy
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2004/11/10GIST 22, Brussels, LMD, M. Viollier26 Diurnal variations using GERB (preliminary) – 2004, January Convective Clouds Area
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2004/11/10GIST 22, Brussels, LMD, M. Viollier27 Diurnal variations using GERB (preliminary) – 2004, January Land (East Africa), clear and partly cloudy Check our local time and SZA computation
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2004/11/10GIST 22, Brussels, LMD, M. Viollier28 Diurnal variations using GERB (preliminary) – 2004, January Valencia, 2.5° area
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2004/11/10GIST 22, Brussels, LMD, M. Viollier29 Conclusion In a first glance : Mean GERB SW and LW fluxes ~ 1 to 3 % low / ES8 CERES (Terra and Aqua) No noticeable gap or anomaly in the diurnal cycles Future works: Compare with SSF fluxes Evaluation of the POLDER nb-bb conversion with GERB SW radiances (availability of 2003 data ?, April to October) Study the n2b conversion of HRI*SEVERI/GERB and the impact of GEO combination on the CERES Terra monthly means computations AMMA, A-train, ScaRaB/Megha-Tropiques, EarthCARE
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