The MODIS Aerosol (MOD04_L2) product contains data that has a spatial resolution (pixel size) of 10 x 10 kilometers (at nadir). Each MOD04_L2 product file covers a five-minute time interval (based on the start time of each MODIS Level-1B granule), which means the MOD04_L2 output grid is 135 10-km (at nadir) pixels in width and 203 10-km (nadir) pixels in length for nine consecutive granules. Every tenth granule has an output grid size of 135 by 204 pixels.
The image below depicts MODIS Level-2 granule coverage during a single simulated orbit. It should be noted that a granule of Level-2 MODIS data is defined as a single Level-2 MODIS product HDF file.
Computation of 10-km Geolocation in 04_L2 Aerosol Products
The geolocation in the standard 04_L2 MODIS Aerosol product is at 10-km resolution. This geolocation is generated from 10x10 1-km L1B input and is computed by averaging the 4 central (5,5), (5,6), (6,5), (6.,6) 1-km L1B input pixels in each 10x10 km area.
Computation of 3-km Geolocation in 04_3K Aerosol Products
The geolocation in the standard 04_3K MODIS Aerosol product is at 3-km resolution. This geolocation is generated from 3x3 1-km L1B input and is computed by sampling the central (2,2) 1-km L1B input pixel in each 3x3 km area.