ICESCAPE Experiment (Arctic)

Project summary:

"Improving existing satellite ocean color observations of the Chukchi and Beaufort Seas for biogeochemical modeling", Robert Frouin, (PDF)

Contacts:

Robert Frouin, PI, (RFrouin@UCSD.edu)
John McPherson, Programmer, (JMcPherson@UCSD.edu)
François Steinmetz (fs@hygeos.com)
Laurent Wandrebeck (lw@hygeos.com)

MERIS Data:

images of marine reflectance and chlorophyll concentration of the Chutki and beaufort Seas
Data files:
- original files: 200806.tar, 200807.tar, 200906.tar, 200907.tar, 201006.tar, 201007.tar
- file listings
  - for 200806.tar (158 files)
  - for 200807.tar (160 files)
  - for 200906.tar (157 files)
  - for 200907.tar (157 files)
  - for 201006.tar (153 files)
  - for 201007.tar (163 files)
Data extracted: logChl, R'865, Rw412, Rw443, Rw490, Rw510, Rw560, Rw620, Rw665, Rw754, Rw779, Rw865
- also available: Rgli, bbs, C0, C1, C2
bitmask info:

bitmask = 1*L1_LAND + 2*CLOUD_MASK_BASE + 4*L1_INVALID + 8*NEGATIVE_BB + 16*OUT_OF_BOUNDS + 32*THRES_RCLOUD_0.03 + 64*THRES_RCLOUD_0.05 + 128*CLOUD_PO2
If b>=128, then set CLOUD_PO2, and b=b-128
If b>=64, then set THRES_RCLOUD_0.05, and b=b-64
If b>=32, then set THRES_RCLOUD_0.03, and b=b-32
If b>=16, then set OUT_OF_BOUNDS, and b=b-16
If b>=8, then set NEGATIVE_BB, and b=b-8
If b>=4, then set L1_INVALID, and b=b-4
If b>=2, then set CLOUD_MASK_BASE, and b=b-2
If b>=1, then set L1_LAND, and b=b-1
binary mask. In decimal notation, "land and cloudy" is 1+2 (except we don't calculate cloud mask over land, so that won't happen).
my advice is to use the following binary mask (in decimal notation) to reject degraded pixels : 1+2+4+8+16 = 31
To use it, you'll have to apply "binary and" to bitmask, and reject non-zero results: reject pixels (i,j) where (bitmask[i,j] & 31) != 0
Also reject pixels where R'865>0.15

Visualization:

Day 2008 06 01:
- image 20080601_005009:
  - NS=1121, NL=769
  - R'865, Chla, and Rw412
- image 20080601_205829:
  - NS=1121, NL=1393 (too big to display at full resolution)
  - R'865, Chla, and Rw412
Day 2008 07 01:
- image 20080701_000657:
  - NS=1121, NL=1393
  - Chla (no mask), and Chla, and Chla (LogScale), and R'865
  - Rw443 (no mask), and Rw443
  - Rw560 (no mask), and Rw560
  - Chla on polar map
  - Composite: R'865,Rw443,Rw560,Chla, sampled 2x2
- image 20080701_014728:
  - NS=1121, NL=321
  - Chla (no mask), and Chla, and Chla (LogScale), and R'865
  - Rw443 (no mask), and Rw443
  - Rw560 (no mask), and Rw560
  - No valid Chl-a data in image, so can't make polar map
- image 20080701_183653:
  - NS=1121, NL=689
  - Chla (no mask), and Chla, and Chla (LogScale), and R'865
  - Rw443 (no mask), and Rw443
  - Rw560 (no mask), and Rw560
  - Chla on polar map
  - Composite: R'865,Rw443,Rw560,Chla, sampled 2x2
- image 20080701_201554:
  - NS=1121, NL=1217 (too big to display at full resolution)
  - Chla (no mask), and Chla, and Chla (LogScale), and R'865
  - Rw443 (no mask), and Rw443
  - Rw560 (no mask), and Rw560
  - Chla on polar map
  - Composite: R'865,Rw443,Rw560,Chla, sampled 2x2
- image 20080701_215508:
  - NS=1121, NL=1681 (too big to display at full resolution)
  - Chla (no mask), and Chla, and Chla (LogScale), and R'865
  - Rw443 (no mask), and Rw443
  - Rw560 (no mask), and Rw560
  - Chla on polar map
  - Composite: R'865,Rw443,Rw560,Chla, sampled 2x2
- image 20080701_233521:
  - NS=1121, NL=1569 (too big to display at full resolution)
  - Chla (no mask), and Chla, and Chla (LogScale), and R'865
  - Rw443 (no mask), and Rw443
  - Rw560 (no mask), and Rw560
  - Chla on polar map
  - Composite: R'865,Rw443,Rw560,Chla, sampled 2x2
- MERIS20080701, Chl-a daily average on polar map
- MERIS20080701, Chl-a multiplot of 5 hours + daily, linear scale on polar map
- MERIS20080701, Chl-a multiplot of 5 hours + daily, log scale on polar map
Day 2008-07-01, hour 20:15:54, to illustrate the difference in spatial coverage
- Chl-a, MEGS
- Chl-a, polymer
- R'865
- Note: The black areas are flagged out:
  - for the MEGS processing, the flag is invalid_algal_1
  - for the Polymer processing, the flag is (bitmask & 31 or R'865>0.15)

Polymer processing of hi-res images from Oceancolor web:

Day 2010 07 02 (julian 183), time 20:41:56
- Oceancolorweb Browse images: true color, and Chl-a
- standard processed image (L2 oceancolorweb), sampled 10x10: Chl-a, and Chl-a (LogScale)
- Polymer processed image, sampled 10x10: Chl-a, and Chl-a (LogScale)
- Composite, standard processing: Rw443,Rw560,Rw665,Chla, sampled 10x10
- Composite, PolyMer processing: Rw443,Rw560,Rw665,Chla, sampled 10x10
Day 2010 07 03 (julian 184), time 20:09:42
- Oceancolorweb Browse images: true color, and Chl-a
- standard processed image (L2 oceancolorweb), sampled 10x10: Chl-a, and Chl-a (LogScale)
- Polymer processed image, sampled 10x10: Chl-a, and Chl-a (LogScale)
- Composite, standard processing: Rw443,Rw560,Rw665,Chla, sampled 10x10
- Composite, PolyMer processing: Rw443,Rw560,Rw665,Chla, sampled 10x10
Note: Rw_Std = pi * Rrs_Std

Polymer applied to MODIS data:

Day 2010_162, 1km resolution
- Chl-a, modis, and legend for image
- Chl-a, polymer, and legend for image
- Note: the MODIS/Polymer is not final processing; for example ozone transmission is not taken into account, so the color scale is not very important.

References:

"Atmospheric correction in presence of sun glint: application to MERIS", François Steinmetz, Pierre-Yves Deschamps and Didier Ramon, (Optics Express, Vol. 19, Issue 10, pp. 9783-9800 (2011), doi:10.1364/OE.19.009783)
"Improved Global Ocean Color using POLYMER Algorithm", François Steinmetz, Didier Ramon, Pierre-Yves Deschamps, Jacques Stum, (PDF)