Antarctic sea ice cover from satellite passive microwave

The 3-day images from the Nimbus 5 electrically scanning microwave radiometer were combined to form monthly average maps and contour plots. These show clearly the yearly cycle from minimum ice extent in February to maximum ice extent from August to September and the spatial distribution of ice 15 to 50 percent concentrated, 50 to 85 percent concentrated, and 85 to 100 percent concentrated. The yearly cycle of the monthly extent of ice is plotted for each of the four years (1973-76). The total 4-year range in monthly mean concentrations (over the 30 km x 30 km grid elements with ice present) is 50 to 80 percent, and the yearly cycle is far less distinct than that for the ice areas.