Satellites—New Global Observing Techniques for Ice and Snow

Abstract

AbstractStarting with the TIROS-2 weather satellite in 1961 which permitted synoptic viewing of large-scale areas with an 011-board television camera system, the capabilities of satellite observations for assessing snow and ice resources on Earth have been greatly improved through the utilization of higher resolution imaging systems and multispectral images in the wavelength range from 0.4 μm to 1.55 cm. The possibility that the variation in areal extent of the snow cover may be related by empirical means to the average monthly run-off in a given watershed was demonstrated by comparing run-off records from the Indus River Basin in south-east Asia with a series of snow-cover maps obtained from Nimbus-3 and 4 imagery. Similar studies using the higher spatial resolution available with ERTS-I imagery were carried out for the Wind River Mountains watersheds in Wyoming, where it was found that the empirical relationship varied with mean elevation of the watershed. In addition, digital image-enhancement techniques are shown to be useful for identifying glacier features thought to be related to extent of snow cover, moraine characteristics, debris coverage, and the like. Finally, longer wavelength observations using sensors on board the Nimbus-5 satellite are shown to be useful for indicating crystal size distributions and onset of melting on glacier snow cover.