Two of India’s geostationary satellites provide a round-the-clock coverage of the southwest monsoon. Kalpana-1, launched on 12 September 2002 and located at 74 °E over the equator, is a dedicated meteorological satellite. INSAT-3A, launched on 10 April 2003 and located at 93.5 °E longitude, has communications as well as meteorological payloads. The images received from these satellites can be viewed on the internet on the web site of the India Meteorological Department (IMD) at www.imd.ernet.in and www.imd.gov.in. The latest Kalpana-1 view of the Indian region is displayed on the home page itself. This is an infra-red channel image that is updated every three hours, sometimes more frequently. The image size is small but by clicking anywhere on the image, an enlarged view gets displayed.

For seeing other types of images, one can click on ‘Satellite Images and Products’ on the home page or go to http://www.imd.gov.in/section/satmet/dynamic/insat.htm for the complete menu. Here one can choose between the full view of the earth or smaller sectors. One can also see the images in visible, infra-red and water vapour channels, or get a colour composite of these grey scale images. The images are updated every three hours except the visible channel images which are not available at night time.

The European Organization for the Exploitation of Meteorological Satellites, EUMETSAT, operates a geostationary meteorological satellite over the Indian Ocean at 57.5°E longitude. Full-disc images received from this satellite, which is called Meteosat-7, can be viewed on the web site of the Dundee Satellite Receiving Station of Dundee University, UK, at www.sat.dundee.ac.uk. For using this web site, a one-time on-line registration is required to be done. The Meteosat-7 images are updated only four times a day, 00, 06, 12 and 18 hrs UTC. A low, medium or high resolution can be chosen as required. The Dundee web site, however, offers the unique advantage of a 30-day archive, so that older images can be easily referenced.

The Meteosat-7 images can also be viewed on the web site of the Cooperative Institute for Meteorological Satellite Studies of the University of Wisconsin at Madison at http://cimss.ssec.wisc.edu/tropic/tropic.html. No registration is involved here. Eight 3-hourly images of the past 24 hours are available at any time, but visible channel images are not included. These are sector images, not full-disc, but the southwest monsoon domain is completely covered in the sector. A major advantage of the CIMMS web site is that the images are superimposed with satellite-derived winds and wind-related products. These can be viewed at http://cimss.ssec.wisc.edu/tropic/real-time/indian/winds/winds.html. The latest Meteosat-7 infra-red image on the CIMMS web site also gets uploaded to the Monsoon On Line web site at http://www.tropmet.res.in/%7Ekolli/MOL/.

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