The Aqua MODIS (Moderate resolution Imaging Spectroradiometer) Level-1B (L1B) product includes calibrated and geolocated at-aperture radiances for 36 bands generated from MODIS Level-1A raw sensor counts. The radiances are provided in watts/m2/micrometer (µm)/steradian. The Aqua MODIS L1B product is a set three datasets (MYD02QKM, MYD02HKM, and MYD021KM) that are produced to address the three spatial-resolution variations: 250 m, 500 m, and 1000 m.

This 1000-meter product is with a short-name MYD021KM. It provides 1000-m calibrated radiances for the 29 Visible and Near-Infrared (VNIR) (bands 8 to 19) and Shortwave Infrared and Thermal Infrared (SWIR & TIR) (bands 20 to 36) bands.

Each 1-km band has 10 detectors in the along-track direction. The MYD021KM product contains the twelve Science Data Sets (SDS) besides geolocation fields for latitude and longitude, quality flags, error estimates, etc.

Besides data and information for the 1-km reflective solar and thermal emissive bands, aggregated 250-m and 500-m bands are also generated through simple weighting functions that are applied to the data at their native resolution. Band 26 is a reflective solar band (RSB), which is handled uniquely. Notwithstanding its RSB status, it is transmitted along with the thermal band data. Consequently, the band order for the night-mode data is re-organized so that the Band 26 data are written to the RSB 1-km SDSs and not to the emissive band SDSs.

The v7.0 Aqua MODIS MYD021KM in netCDF4 format represents the most current version of this product that has undergone around half-a-dozen reprocessing cycles in the last 2.5 decades. Each 1000-m swath granule or data-file temporally spans 5 minutes and its image dimensions measure 2,030 lines (along-track direction) by 1,354 samples (cross-track direction). The v7.0 collection’s data record starts from July 4, 2002 (2002–185). Consult the MODIS L1B User Guide to understand how to convert the per-pixel scaled integers to radiance or reflectance.