Presentation is loading. Please wait.

Presentation is loading. Please wait.

2004/04/02GIST 21, Boulder M. Viollier et al.1 Time sampling bias: combination of CERES with Meteosat narrow-bands and beginning a comparison with GERB.

Published byFrancis Sims Modified over 9 years ago

Similar presentations

Presentation on theme: "2004/04/02GIST 21, Boulder M. Viollier et al.1 Time sampling bias: combination of CERES with Meteosat narrow-bands and beginning a comparison with GERB."— Presentation transcript:

1 2004/04/02GIST 21, Boulder M. Viollier et al.1 Time sampling bias: combination of CERES with Meteosat narrow-bands and beginning a comparison with GERB Michel Viollier, Patrick Raberanto, Robert Kandel Laboratoire de Météorologie Dynamique, IPSL/CNRS, Ecole Polytechnique Palaiseau, France

2 2004/04/02GIST 21, Boulder M. Viollier et al.2 Important issue on the SW monthly means … can the low 1999-2002 SW flux be explained by diurnal effects ? linked to the 10:30 observation local time ? 1985-89 Radiative Anomaly (Wm -2 )- Wielicki etal. 2002 Scanners CERES ScaRaB NOAA-ERBS

3 2004/04/02GIST 21, Boulder M. Viollier et al.3 Outline objective: to search for a possible diurnal bias in the Terra alone computations: - comparison of diurnal cycles and monthly means from Terra and Aqua July 2002, March 2000 - combination of Meteosat-5 with CERES/Terra, July 2002, and comparison with Terra+Aqua ; second example: March 2000 - beginning GERB/CERES comparisons and diurnal variations over selected areas

4 2004/04/02GIST 21, Boulder M. Viollier et al.4 CERES SW : Aqua minus Terra, 2002 July, Sep, Dec. Compared to Terra, Aqua misses morning reflected flux from marine stratus, but is sensitive to afternoon convective activity on continents, and vice versa. [December/Antartic: instrument/angular differences are amplified by the very large solar incident flux] Jul Sep Dec

5 2004/04/02GIST 21, Boulder M. Viollier et al.5 Aqua, Terra ES 9 differences: Min and Max ( Wm -2 ) Minimum differences near western continent coast Maximum differences inland areas ERBE Region Wm -2 ERBE Region Wm -2 Jul 2002 4901 Cameroon -30 3126 New Mex. US 44 Sep 2002 5622 Angola -39 5126 Lake Victoria 33 Dec 2002 6306 off Peru -31 6211 Madagascar 22

6 2004/04/02GIST 21, Boulder M. Viollier et al.6 Aqua, Terra ES 9 regional instantaneous albedo July 2002 Cameroon /east Atlantic sw flux monthly m. A qua –Terra= - 30 Wm -2 New Mexico USA /inland area Aqua –Terra= + 44 Wm -2 Red=monthly mean Terra Aqua

7 2004/04/02GIST 21, Boulder M. Viollier et al.7 CERES Aqua, Terra : SW 20°S-20N Means ( Wm -2 ) 2002Aqua FM3 Ed1 Terra E d2 S9(Aq+Te) Ed1 Aqua minus Terra Aqua minus S9(Aq+Te) Jul90.4589.7690.02+0.7-0.3 Aug94.2393.6393.88+0.6-0.2 Sep93.9392.0392.53+1.9-0.5 Oct94.2792.5792.98+1.7-0.4 Nov93.8594.7594.81-0.9-0.1 Dec91.5192.5592.43+0.1 < 0.5 Wm -2 Combination of Terra and Aqua don’t change significantly the tropical SW mean.

8 2004/04/02GIST 21, Boulder M. Viollier et al.8 Compare ES9 Terra and Aqua with contemporaneous Meteosat-5 : JULY 2002 SW LW Study over the INDOEX area (1999 study following-on )

9 2004/04/02GIST 21, Boulder M. Viollier et al.9 SW Monthly Means Computations with CERES/Meteosat-5 combinations -estimate instantaneous fluxes from Meteosat-5 -average the fluxes (2.5°x2.5°) and fill the 24x31 day-hour table (applying cos SZA corrections between observation time and local half-hour, eliminating spurious data, twilight and night-time data) -use ‘our ERBE-type’ code, with CERES flux estimates -use the GEO observed diurnal albedo variation shape in place of the ERBE modeled albedo basically the same approach as the GEO interp. of CERES/SRBAVG

10 2004/04/02GIST 21, Boulder M. Viollier et al.10 Estimation of Meteosat-5fluxes by comparison to CERES. Examples: July 2002 FM2 (Terra) FM4 (Aqua) Meteosat flux conversion: based on ScaRaB 1999 (Viollier et al., JGR 2004)

11 2004/04/02GIST 21, Boulder M. Viollier et al.11 Ethiopia ERBE-type extrapolation with Meteosat Diff= 120-102=18 Wm -2 DIURNAL EXTRAPOLATION

12 2004/04/02GIST 21, Boulder M. Viollier et al.12 Ocean W. Australia ERBE-type extrapolation with Meteosat Diff= 70.7-74.8=-4 Wm -2

13 2004/04/02GIST 21, Boulder M. Viollier et al.13 Red Sea ERBE-type extrapolation with Meteosat Diff= 60.6-61.8=-1,2 Wm -2

14 2004/04/02GIST 21, Boulder M. Viollier et al.14 Terra/Meteosat-5 correction - July 2002 Area of predominant morning cloudiness: over ocean west of Australia Difference between M5-Terra SW combination and ERBE-type extrapolation Mean ~ + 3,35 Wm -2 Area of predominant afternoon cloudiness, Ethyopia

15 2004/04/02GIST 21, Boulder M. Viollier et al.15 ES9(2 sat) - ES9(Terra) Terra/Meteosat-5 correction but 27-31 July Meteosat data are available to us from Aqua –Terra (Takmen Wong, Oct. 15) same but # colors, grid, interp. Mean=0.743.35

16 2004/04/02GIST 21, Boulder M. Viollier et al.16 SW Monthly Means Computations with CERES/Meteosat-5 combinations, March 2000 Difference between M5-Terra SW combination and ERBE-type extrapolation Mean ~ + 4 Wm -2 Same but for region of predominant afternoon cloudiness, over ocean northwest of Madagascar (long.=56°E, lat.=6°S) Area of predominant morning cloudiness: monthly means of the diurnal cycle for albedo (left) and LW flux (right), over ocean west of Australia (long.= 104°E, lat.=29°S) (Viollier et al., JGR 2004)

17 2004/04/02GIST 21, Boulder M. Viollier et al.17 preliminary GERB comparisons - GERB data: 19, 23 Dec. 2003 ( ex. G2_SEV1_L20S_20031223_130000_V002.hdf ) - CERES : ES8 ( ex CER_ES8_Aqua-FM3_Edition1_025023.20031223 ) - average data over 2.5 x 2.5° regions - keep region with more than 80 (CERES) and 20 (GERB) observations - compare GERB and CERES flux regional means with time condition: ± 10 minutes (LW), ± 2 minutes (SW), - other comparisons: radiance, reflectance, albedo - observe selected regional diurnal cycles (albedo, LW flux)

18 2004/04/02GIST 21, Boulder M. Viollier et al.18 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,.. )

19 2004/04/02GIST 21, Boulder M. Viollier et al.19 Diurnal variations using GERB (preliminary) – 2003, Dec. 19 Clear Ocean (Arabian Gulf)Clear Land (S. Africa)

20 2004/04/02GIST 21, Boulder M. Viollier et al.20 Diurnal variations using GERB (preliminary) – 2003, Dec. 19 off Angola Africa low cloud area convective cloud area

21 2004/04/02GIST 21, Boulder M. Viollier et al.21 Conclusions SW differences of tropical monthly means between computations from one (Terra) or two satellites (Terra+Aqua, Ed1) are not significant (0.5 Wm -2 )  the addition of Aqua in the monthly means calculations doesn't show any sufficient diurnal bias to explain the low SW fluxes observed by Terra since 2000 over INDOEX area : combination with Meteosat suggests Terra monthly means might be underestimated by ~4 Wm -2, and then diurnal bias could partly explain the low CERES SW fluxes further analysis of GERB and of the CERES geo-interpolations are necessary to confirm this conclusion with still several issues: inter-calibration and radiance-to-flux conversions

22 2004/04/02GIST 21, Boulder M. Viollier et al.22 back up slides

23 2004/04/02GIST 21, Boulder M. Viollier et al.23 Beside presentation : AMMA as a potential GERB data user (1/2) 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. Sponsors : French Agencies CNES, CNRS/INSU, IRD, and Meteo-France. International participation: Africa, Germany, the UK, and the United States,…

24 2004/04/02GIST 21, Boulder M. Viollier et al.24 AMMA as a potential GERB data user (2/2) Long Term Observation Period : … 2009 Special Observing Period (SOP): various key stages of the rainy season during three periods in 2005: (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 emphasize the value of CERES and GERB data

Download ppt "2004/04/02GIST 21, Boulder M. Viollier et al.1 Time sampling bias: combination of CERES with Meteosat narrow-bands and beginning a comparison with GERB."

Similar presentations

© University of Reading 2010 1 Richard Allan Department of Meteorology, University of Reading Thanks to: Jim Haywood and Malcolm.

© University of Reading Richard Allan Department of Meteorology, University of Reading Thanks to: Jim Haywood and Malcolm.
Figure 1: Using GERB and SEVIRI data to evaluate the Met Office NWP model in near-real time; example SINERGEE comparisons for 8 th March 2006 at 1200 UTC.

Figure 1: Using GERB and SEVIRI data to evaluate the Met Office NWP model in near-real time; example SINERGEE comparisons for 8 th March 2006 at 1200 UTC.
IRS2004, Busan, August 2004 Using Satellite Observations and Reanalyses to Evaluate Climate and Weather Models Richard Allan Environmental Systems Science.

IRS2004, Busan, August 2004 Using Satellite Observations and Reanalyses to Evaluate Climate and Weather Models Richard Allan Environmental Systems Science.
Changes in clear-sky longwave radiative cooling in the atmosphere 1979-2004 Richard Allan Environmental Systems Science Centre, University of Reading,

Changes in clear-sky longwave radiative cooling in the atmosphere Richard Allan Environmental Systems Science Centre, University of Reading,
1 Evaluating climate model using observations of tropical radiation and water budgets Richard P. Allan, Mark A. Ringer Met Office, Hadley Centre for Climate.

1 Evaluating climate model using observations of tropical radiation and water budgets Richard P. Allan, Mark A. Ringer Met Office, Hadley Centre for Climate.
Evaluating the Met Office global forecast model using GERB data Richard Allan, Tony Slingo Environmental Systems Science Centre, University of Reading.

Evaluating the Met Office global forecast model using GERB data Richard Allan, Tony Slingo Environmental Systems Science Centre, University of Reading.
EUMETSAT 2006 Helsinki Exploitation of GERB/SEVIRI data for evaluation of the Met Office global forecast model Richard Allan, Tony Slingo Environmental.

EUMETSAT 2006 Helsinki Exploitation of GERB/SEVIRI data for evaluation of the Met Office global forecast model Richard Allan, Tony Slingo Environmental.
GERB/CERES Meeting 2006 Exeter Evaluation of clouds and radiation in the Met Office global forecast model using GERB/SEVIRI data Richard Allan, Tony Slingo.

GERB/CERES Meeting 2006 Exeter Evaluation of clouds and radiation in the Met Office global forecast model using GERB/SEVIRI data Richard Allan, Tony Slingo.
Recent Evidence for Reduced Climate Sensitivity Roy W. Spencer, Ph.D Principal Research Scientist The University of Alabama In Huntsville March 4, 2008.

Recent Evidence for Reduced Climate Sensitivity Roy W. Spencer, Ph.D Principal Research Scientist The University of Alabama In Huntsville March 4, 2008.
GERB-2 GEO 22/11/05 J. Hanafin Using IDL coastline information as independent check on L15 and L2 Geolocations Only SW and SWF day time radiances used.

GERB-2 GEO 22/11/05 J. Hanafin Using IDL coastline information as independent check on L15 and L2 Geolocations Only SW and SWF day time radiances used.
GERB SW fluxes: an update (Clear ocean SW radiances and fluxes in the reprocessed V999 June 04 data) Cédric Bertrand GIST 24 14-16 th December, Imperial.

GERB SW fluxes: an update (Clear ocean SW radiances and fluxes in the reprocessed V999 June 04 data) Cédric Bertrand GIST th December, Imperial.
Earth Radiation Budget Studies over the tropical monsoon region using satellite data P. C. Joshi Meteorology and Oceanography Group Space Applications.

Earth Radiation Budget Studies over the tropical monsoon region using satellite data P. C. Joshi Meteorology and Oceanography Group Space Applications.
TOA radiative flux diurnal cycle variability Patrick Taylor NASA Langley Research Center Climate Science Branch NEWS PI Meeting.

TOA radiative flux diurnal cycle variability Patrick Taylor NASA Langley Research Center Climate Science Branch NEWS PI Meeting.
Surface Skin/Air Temperature and LW Flux Calculation Y-C. Zhang and W.B. Rossow LandFlux Conference CNES/CESBIO, Toulouse, France May 28 – 31, 2007.

Surface Skin/Air Temperature and LW Flux Calculation Y-C. Zhang and W.B. Rossow LandFlux Conference CNES/CESBIO, Toulouse, France May 28 – 31, 2007.
Characterizing the Diurnal Cycle in a Global Analysis/Forecast System Alex Ruane John Roads Masao Kanamitsu Experimental Climate Prediction Center Scripps.

Characterizing the Diurnal Cycle in a Global Analysis/Forecast System Alex Ruane John Roads Masao Kanamitsu Experimental Climate Prediction Center Scripps.
Diurnal asymmetry in the GERB(-like) fluxes: an update Cédric Bertrand Royal Meteorological Institute of Belgium, Brussels, Belgium.

Diurnal asymmetry in the GERB(-like) fluxes: an update Cédric Bertrand Royal Meteorological Institute of Belgium, Brussels, Belgium.
Megha-Tropiques Workshop, Ahmedabad, October 20051 ScaRaB / Megha-Tropiques: objectives, description, calibration and radiance-to-flux conversion ScaRaB:

Megha-Tropiques Workshop, Ahmedabad, October ScaRaB / Megha-Tropiques: objectives, description, calibration and radiance-to-flux conversion ScaRaB:
The Radiative Budget of an Atmospheric Column in Tropical Western Pacific Zheng Liu Department of Atmospheric Science University of Washington.

The Radiative Budget of an Atmospheric Column in Tropical Western Pacific Zheng Liu Department of Atmospheric Science University of Washington.
The Radiative Budget of an Atmospheric Column in Tropical Western Pacific Zheng Liu 1 Thomas Ackerman 1,2, Sally McFarlane 2, Jim Mather 2, University.

The Radiative Budget of an Atmospheric Column in Tropical Western Pacific Zheng Liu 1 Thomas Ackerman 1,2, Sally McFarlane 2, Jim Mather 2, University.
Lunar Observations of Changes in the Earth’s Albedo (LOCEA) Alexander Ruzmaikin Jet Propulsion Laboratory, California Institute of Technology in collaboration.

Lunar Observations of Changes in the Earth’s Albedo (LOCEA) Alexander Ruzmaikin Jet Propulsion Laboratory, California Institute of Technology in collaboration.

Similar presentations

Ads by Google