How good are SST4/SST11 algorithms ?
Posted: Wed Apr 28, 2021 8:17 am America/New_York
Hello,
I started to work on MODIS-A SST (processed from L1 to L3m, saving SST(11 and 4), Vis/NIR/BTs reflectances (TOA/BOA)) for my area, the North Sea.
When I look at a random map, let say the 20th of April 2005 (AQUA_MODIS.20050420T121505.L2.SST.nc, https://oceancolor.gsfc.nasa.gov/cgi/br ... =D&prm=SST), I see values from -40 to 20°C for this image. I can understand that the -40s are associated to the clouds, but then is it still a "sea surface" algorithm ? I masked the clouds using cldice for my processed data (because I initially wanted the visible signal) so it is not a real issue, but I would like to know if this is normal.
I have some questions :
1) What in situ measurements have been used to train the sst4 / sst11 algorithms ? Temperature measurements above the sea ? At "1" meter depth ? Something else ?
2) How good should the algorithm be compared to the in situ data (the usual 1 m), what difference should I expect ? +/- 1°C ? 5 ?
3) Should I use the sst 4 or sst 11 algorithm for daylight comparison with my in situ sea surface temperatures ?
Thank you
I started to work on MODIS-A SST (processed from L1 to L3m, saving SST(11 and 4), Vis/NIR/BTs reflectances (TOA/BOA)) for my area, the North Sea.
When I look at a random map, let say the 20th of April 2005 (AQUA_MODIS.20050420T121505.L2.SST.nc, https://oceancolor.gsfc.nasa.gov/cgi/br ... =D&prm=SST), I see values from -40 to 20°C for this image. I can understand that the -40s are associated to the clouds, but then is it still a "sea surface" algorithm ? I masked the clouds using cldice for my processed data (because I initially wanted the visible signal) so it is not a real issue, but I would like to know if this is normal.
I have some questions :
1) What in situ measurements have been used to train the sst4 / sst11 algorithms ? Temperature measurements above the sea ? At "1" meter depth ? Something else ?
2) How good should the algorithm be compared to the in situ data (the usual 1 m), what difference should I expect ? +/- 1°C ? 5 ?
3) Should I use the sst 4 or sst 11 algorithm for daylight comparison with my in situ sea surface temperatures ?
Thank you