Satellite passive microwave observations and analysis of Arctic and Antarctic sea ice, 1978–1987

Abstract

We have recently completed an analysis that examines in detail the spatial and temporal variations in global sea-ice coverage from 26 October 1978, through 20 August 1987. The sea-icemeasurements we analyzed are derived from data collected by a multispectral, dual-polarized, constant incidence-angle microwave imager, the Scanning Multichannel Microwave Radiometer (SMMR) on board the NASA Nimbus 7 satellite. The characteristics of the SMMR have permitted a more accurate calculation of total sea-ice concentrations (fraction of ocean area covered by sea ice) than earlier single-channel instruments and, for the first time, a determination of both multiyear sea-ice concentrations and physical temperatures of the sea-ice pack. An estimate of the SMMR wintertime total ice concentration accuracy of ± 7% in both hemispheres has been obtained. As this is an improvement over the estimated accuracies of previous microwave sensors, we are able to present improved calculations of the sea-ice extents (areas enclosed by the 15% ice concentration boundaries), sea-ice concentrations, and open-water areas within the ice margins. This analysis will be published in a book, Arctic and Antarctic sea ice, 1978–1987: satellite passive microwave observations and analysis, due for publication in1992. Some highlights from the analysis are presented in this paper.