Duplicate Terra granules between 2003 and 2017
Posted: Tue May 31, 2022 4:03 pm America/New_York
Hi,
It seems that the L2 browser returns duplicate products for MODIS Terra between around [2003-01-01, 2017-06-24] with roughly 320 granules per day instead of 190.
Example:
https://oceancolor.gsfc.nasa.gov/cgi/browse.pl?sub=level1or2&per=DAY&day=17332&prm=CHL&set=10&mon=17318&sen=tmod&rad=0&frc=0&n=39.7265625&w=5.2734375&id=1654026908.259537&cn=40.48&cs=38.95&cw=4.46&ce=6.04&dnm=D&file=T2017166104000.L2_LAC_OC.nc_CHLOR_A_BRS&ndx=0&wid=170&hgt=254
and
https://oceancolor.gsfc.nasa.gov/cgi/browse.pl?sub=level1or2&per=DAY&day=17332&prm=CHL&set=10&mon=17318&sen=tmod&rad=0&frc=0&n=39.7265625&w=5.2734375&id=1654026908.259537&cn=40.48&cs=38.95&cw=4.46&ce=6.04&dnm=D&file=T2017166104000.L2_LAC_OC.nc_CHLOR_A_BRS&ndx=1&wid=170&hgt=254
Is it normal? Seems like database duplicates.
We try to estimate the size of the whole archive and it seems these duplicates have a big impact on the estimate. We found 1943173 Terra granules vs 1193721 for Aqua which seems suspect if they have the same theoretical number of granules per day (Aqua mission has 22 years of data vs 20 years for Aqua).
Thanks,
Julien
It seems that the L2 browser returns duplicate products for MODIS Terra between around [2003-01-01, 2017-06-24] with roughly 320 granules per day instead of 190.
Example:
https://oceancolor.gsfc.nasa.gov/cgi/browse.pl?sub=level1or2&per=DAY&day=17332&prm=CHL&set=10&mon=17318&sen=tmod&rad=0&frc=0&n=39.7265625&w=5.2734375&id=1654026908.259537&cn=40.48&cs=38.95&cw=4.46&ce=6.04&dnm=D&file=T2017166104000.L2_LAC_OC.nc_CHLOR_A_BRS&ndx=0&wid=170&hgt=254
and
https://oceancolor.gsfc.nasa.gov/cgi/browse.pl?sub=level1or2&per=DAY&day=17332&prm=CHL&set=10&mon=17318&sen=tmod&rad=0&frc=0&n=39.7265625&w=5.2734375&id=1654026908.259537&cn=40.48&cs=38.95&cw=4.46&ce=6.04&dnm=D&file=T2017166104000.L2_LAC_OC.nc_CHLOR_A_BRS&ndx=1&wid=170&hgt=254
Is it normal? Seems like database duplicates.
We try to estimate the size of the whole archive and it seems these duplicates have a big impact on the estimate. We found 1943173 Terra granules vs 1193721 for Aqua which seems suspect if they have the same theoretical number of granules per day (Aqua mission has 22 years of data vs 20 years for Aqua).
Thanks,
Julien