Hi @zhooukee
It is a priority to use the observation that makes up the largest percentage of a given Sinusoidal gridded MODIS pixel. Each MODIS tile is geographically fixed. So, by that I mean any given pixel from any gridded Sinusoidal product from any day or temporal range will have the exact upper left identifying coordinate. However, these are originally produced from the L1B MOD/MYD02 radiance swath products and these pixels are not gridded and are not constant. For example, a 1-kilometer pixel at nadir is 1-kilometer square at the edge of the swath a 1-k pixel is 4.8-k cross track and 2-k along track.
Primarily this applies to pixels that are off nadir. Which the satellites that the MODIS sensors are on board have a 16-day revisit cycle and this is an 8-day product so there will certainly be pixels off nadir. Hence the User Guide says: "The criteria for selection include observational coverage and view angle, and whether the observation is flagged as cloudy, clear, containing high aerosol or low aerosol, or in cloud shadow."
MODAPS in the past had a portal users could register for to download the processing programs. I do not know if that still exists. If it does you will need to contact them: https://modaps.modaps.eosdis.nasa.gov/services/production/pge_versions.html
Thanks,
Brett
It is a priority to use the observation that makes up the largest percentage of a given Sinusoidal gridded MODIS pixel. Each MODIS tile is geographically fixed. So, by that I mean any given pixel from any gridded Sinusoidal product from any day or temporal range will have the exact upper left identifying coordinate. However, these are originally produced from the L1B MOD/MYD02 radiance swath products and these pixels are not gridded and are not constant. For example, a 1-kilometer pixel at nadir is 1-kilometer square at the edge of the swath a 1-k pixel is 4.8-k cross track and 2-k along track.
Primarily this applies to pixels that are off nadir. Which the satellites that the MODIS sensors are on board have a 16-day revisit cycle and this is an 8-day product so there will certainly be pixels off nadir. Hence the User Guide says: "The criteria for selection include observational coverage and view angle, and whether the observation is flagged as cloudy, clear, containing high aerosol or low aerosol, or in cloud shadow."
MODAPS in the past had a portal users could register for to download the processing programs. I do not know if that still exists. If it does you will need to contact them: https://modaps.modaps.eosdis.nasa.gov/services/production/pge_versions.html
Thanks,
Brett
Statistics: Posted by LP DAAC - lien — Tue Apr 16, 2024 2:43 pm America/New_York