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Fig. 4: S-Band cyclone detection radar network.
(5.7-7.1 m) with resolution of 2 × 2 km (Goyal et al., 2013) in visible and 8 ×
8 km in water vapour (WV) and Infra red (IR) channels. In addition, the INSAT-
3A has a three-channel Charge Coupled Device (CCD) payload for imaging
the earth in Visible (0.62-0.69 m), Near IR (0.77-0.86 m) and Short Wave
IR (1.55-1.77 m) bands of spectrum. The Resolution of CCD payload in all
the three channels is 1 km × 1 km. At present about 48 satellite images are
taken daily from Kalpana-1 which is the main operational satellite and
approximately 20 images are taken from INSAT-3A. Imaging from CCD is
done five times during daytime only. All the received data from the satellite
are processed and archived in National Satellite Data Centre (NSDC), New
Delhi. A typical TC imagery by INSAT satellite is shown in Fig. 3.
Dvorak technique with its international algorithm (Dvorak, 1975, 1984)
has been the mainstay of analysis. Cloud imageries from geostationary
meteorological satellites INSAT-3A and METSAT (Kalpana-1) are the main
sources of information for the analysis of tropical cyclones over the data-sparse
region of north Indian Ocean. Recently efforts have been made for automation
of this technique. Automated Dvorak technique is running in experimental
mode at Synoptic Application Unit, Satellite Meteorology Division. Satellite
Application Unit is also using microwave imageries operationally from NOAA,
Metops, DMSP satellites for locating the tropical systems. Apart from generating
half hourly cloud imagery, the following derived products are processed in
IMD (RSMC, 2012):
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