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Now that many of the recently launched GEO imagers have multiple reflective solar band channels, the DCCRM algorithm is being modified to inter-calibrate those channels as well, especially for the SWIR bands. The spectral uniformity of the DCC over the SWIR bands is not uniform, given that the ice particle absorption is a function of wavelength. New Spectral Band Adjustment Factor (SBAF) strategies will need to be developed. DCC-RM is also wellsuited to inter-calibrate historical near-broadband visible GEO imagers. DCC are spectrally flat across the visible spectrum, which reduces the SBAF uncertainty between two ray-matched sensors. Applying the DCC-RM technique on historical GEO imagers is challenging due to the coarser pixel and temporal resolution of the ISCCP B1U formatted dataset. The ATO-RM and DCC-RM calibration methods were applied to multiple visible bands on Himawari-8 using MODIS as the calibration reference. The Aqua-MODIS and Himawari-8 calibration difference was less than 0.4% for wavelengths less than 1 µm and for the Terra-MODIS 0.65-μm channel. Other channel combinations would need further examination to obtain consistent ATO and DCC gain results. The ATO-RM and DCC-RM calibration methods were also applied to GOES-8 in the ISCCP B1U format with NOAA-14 AVHRR as the calibration reference. The GOES-8 ATO and DCC calibration gain difference was within 0.15%. The agreement between ATO and DCC gains provides confidence in both methods. |
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Calibration
MODIS
Imaging systems
Clouds
Reflectivity
Visible radiation
Satellites
