MODIS/Aqua Calibrated Radiances 5-Min L1B Swath 500m V7

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 landing page describes the 500-meter product with a short-name MYD02HKM. It provides 500-m calibrated radiances for the following 5 bands:

Band Wavelength Band 3 (Blue) 0.459–0.479 µm Band 4 (Green) 0.545–0.565 µm Band 5 (Near-Infrared (NIR)) 1.230–0.250 µm Band 6 (Shortwave Infrared (SWIR)) 0.628–1.652 µm Band 7 (SWIR) 2.105–2.155 µm

Each 500-m band has 20 detectors in the along-track direction. The MYD02HKM product contains the following five Science Data Sets (SDS) besides geolocation fields for latitude and longitude, quality flags, error estimates, etc.

SDS Variable Long-name EV_250_Aggr500_RefSB Earth View 250M Aggregated 500M Reflective Solar Bands Scaled Integers EV_250_Aggr500_RefSB_Samples_Used Earth View 250M Aggregated 500M Reflective Solar Bands Number of Samples Used in Aggregation EV_250_Aggr500_RefSB_Uncert_Indexes Earth View 250M Aggregated 500M Reflective Solar Bands Uncertainty Indexes EV_500_RefSB Earth View 500M Reflective Solar Bands Scaled Integers EV_500_RefSB_Uncert_Indexes Earth View 500M Reflective Solar Bands Uncertainty Indexes

As evident from the above table, the 250-m (red and near-infrared) bands are also aggregated to 500 m through simple weighting functions that are applied to the data at their native resolution.

The v7.0 Aqua MODIS MYD02HKM 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 500-m swath granule or data-file temporally spans 5 minutes and its image dimensions measure 4,060 lines (along-track direction) by 2,708 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.