Cover Sunglint in INSAT-VHRR images

INT. J. REMOTE SENSING, 1996, VOL. 17, No.7, 1275-1277 Cover Sunglint in INSAT-VHRR images S. M. BHANDARI and W. J. PRAKASH Meteorology and Oceanography Group, Space Applications Centre, ISRO Ahmedabad 380 053, India SungJint, resulting from the imaging of the visible solar radiation specularly reflected by the ocean surface into the spaceborne sensor, has long been recognised, both in terms of its nuisance value in making ocean observations as well as for its potential in providing useful information about the roughness characteristics of the reflecting surface of the ocean (Cox and Munk 1954). Presence of sunglint also tends to accentuate the contrast between the rough and smooth regions of the ocean allowing better delineation of signatures of otherwise feeble low-contrast features associated with internal waves, oil slicks, plankton blooms etc. (La Violette et al. 1980, Andharia et al. 1986). Sunglint signatures have been studied in images from polar as well as geostation­ ary meteorological satellites. Occasionally, sunglint signatures in photographs from manned missions, e.g., Apollo-Soyuz, Salyut and Space Shuttle have also been examined (Levanon 1971, Khattak et al. 1991, Andharia et al. 1986). Attempts have been made in the past to develop methods for estimation of surface wind speeds over the ocean using the roughness characteristics derived from sunglint measurements (Strong and Ruff 1970, Wald and Monget 1983, Cracknell 1990, Bhandari et al. 1994). While there exists a sufficient case for designing oceanographic sensors and missions to image and exploit sunglint signatures systematically for oceanographic studies, oceanographic sensors and satellites...