09 Sept. 2004 ENVISAT symposium, Salzburg Aerosol over land with MERIS, present and future Ramon, D....
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Transcript of 09 Sept. 2004 ENVISAT symposium, Salzburg Aerosol over land with MERIS, present and future Ramon, D....
09 Sept. 2004ENVISAT symposium, Salzburg
Aerosol over land with MERIS, present and future
Ramon, D.1 and Santer, R.2
(1) HYGEOS, France
(2) LISE, Université du Littoral, France
09 Sept. 2004ENVISAT symposium, Salzburg
Where did we start after Salzburg
MERIS level 2 products Reprocessing #2 after MAVT Workshop
oct. 2003 recommendations Increase aerosol model number (Angstrom
coeff. from 0 to 2.5 by step of 0.1) Extend the aerosol product spatial cover
From Dense Dark Vegetation to Land Aerosol Remote Sensing target
09 Sept. 2004ENVISAT symposium, Salzburg
LARS concept
Surface reflectance varies linearly with some spectral index, here ARVI
ARVI=0
ARVI=-0.2
ARVI=-0.5
100x100 RRaround Alta Floresta
09 Sept. 2004ENVISAT symposium, Salzburg
LARS Reflectance for a biome
svsvLARS m ,,,,
)))(,(1(,,,)( ARVILARVImmC svsvDDV
Seasonal Initial DDV slope DomainInitial DDV
09 Sept. 2004ENVISAT symposium, Salzburg
Biomes
10
2
3 45
6 7
8
9
10
09 Sept. 2004ENVISAT symposium, Salzburg
Biome transition on level 3
09 Sept. 2004ENVISAT symposium, Salzburg
Spatially Complete Global Surface Albedos Derived from Terra/MODIS Data
Michael D. King1, Eric G. Moody1,2, Steven Platnick1, and Crystal Schaaf3
1NASA Goddard Space Flight Center2L3-Communications GSI
3Boston University
Operational MODIS surface albedo data product (MOD43B3/MCD43B3) 0.47, 0.56, 0.67, 0.86, 1.24, 1.64, 2.1 µm , 0.3-5.0, 0.7-5.0, 0.3-0.7 µm 1 km spatial resolution (sinusoidal projection stored as 10° x 10° tiles) 16-day periodicity (001, 017, …, 353)
09 Sept. 2004ENVISAT symposium, Salzburg
12'x12' box fit ()goodness of fit16 days period starting from julian day
09 Sept. 2004ENVISAT symposium, Salzburg
12' resolution, day 177, slope at 659 nm
Black: no fitWhite: no good fit
09 Sept. 2004ENVISAT symposium, Salzburg
0
0.0812' resolution, day 177, albedo at 659 nm for ARVI=0.6
09 Sept. 2004ENVISAT symposium, Salzburg
C443
0
1.5
09 Sept. 2004ENVISAT symposium, Salzburg
C670
0
1.5
09 Sept. 2004ENVISAT symposium, Salzburg
New RO_LARS LUTs from MODIS Aerosol product: AOT_865 and alpha
09 Sept. 2004ENVISAT symposium, Salzburg
Remaining issues?
See biome transitions on AOT_865 Lot of alpha out of range
09 Sept. 2004ENVISAT symposium, Salzburg
Flags
Clouds(White); water (Black),LARS with good aerosol retrieval(Green); Bad aerosol retrieval (Red) LARS in cloud vicinity(Blue)
09 Sept. 2004ENVISAT symposium, Salzburg
AOT_865
09 Sept. 2004ENVISAT symposium, Salzburg
RO_LARS_670
DDV albedo (red) corrected LARS albedo (magenta)
09 Sept. 2004ENVISAT symposium, Salzburg
Rayleigh corrected reflectance above LARS at 443nm
09 Sept. 2004ENVISAT symposium, Salzburg
Rayleigh corrected reflectance above LARS at 670 nm
09 Sept. 2004ENVISAT symposium, Salzburg
What aerosol product?
RO_AER_440 is correct but improvements are possible
RO_AER_670 is questionable
Laerosol _440 is OK
AOT_440 instead of AOT_865 (no compromise at 670 nm)
What about and the associated Junge size distribution
09 Sept. 2004ENVISAT symposium, Salzburg
The 3 possible algorithms
Simultaneous retrieval of AOT and alpha AOT for model no 36 (=1) Use AOT for model no 36 as back up only
09 Sept. 2004ENVISAT symposium, Salzburg
Spatial & temporal binning (nov.)
09 Sept. 2004ENVISAT symposium, Salzburg
Spatial & temporal binning (sept.)
09 Sept. 2004ENVISAT symposium, Salzburg
Conclusion
Separate AOT retrieval and alpha retrieval
Coherence with AOT over water No real biome transition found, but need
to consolidate with L3 Better cloud rejection at level 2 is
mandatory Less problem with a better surface
albedo map !
09 Sept. 2004ENVISAT symposium, Salzburg
What next?
How to make a good surface albedo map for dark pixels?
Utility of a level 2 aerosol product? On a pixel by pixel basis? A daily level 3 which is not a simple bining
Utility of a daily level 3 aerosol product? Validation Atmospheric correction Upper level