INSAT-3DR Imager

INSAT-3DR Imager is the mission's six-channel geostationary meteorological imager, separate from the 19-channel INSAT-3DR Sounder ^[1][2]. It provides visible, shortwave-infrared, mid-wave infrared, water-vapour, and split-window thermal-infrared imaging for cloud, surface, and radiance products over the Indian Ocean region ^[1][3]. The band set is VIS 0.52-0.72 um, SWIR 1.55-1.70 um, MWIR 3.80-4.00 um, water vapour 6.50-7.00 um, TIR-1 10.2-11.2 um, and TIR-2 11.5-12.5 um ^[1]. Ground sampling is 1 km for VIS/SWIR, 4 km for MWIR and thermal-window bands, and 8 km for the water-vapour band; the payload uses 10-bit imaging ^[1]. Demonstrated uses include atmospheric motion vectors from image sequences, sea-surface-temperature retrieval from split-window infrared channels, and broadband radiometry products such as outgoing longwave radiation ^[1]. The imager is best matched to repeated full-disc meteorological imaging and derived cloud, wind, radiation, and surface-temperature products, not vertical atmospheric profile retrieval ^[1][3].