Seasonal ice area and volume production of the Arctic Ocean: November 1996 through April 1997

Abstract

The RADARSAT Geophysical Processor System (RGPS) produces estimates of sea ice motion, deformation, and thickness of the Arctic Ocean sea ice cover from time‐sequential synthetic aperture radar (SAR) imagery acquired by RADARSAT. Based on these products, we summarize the evolution of a region of the Arctic Ocean ice cover in terms of its area change, ice volume production, and multiyear ice coverage over a 6‐month period between 7 November 1996 through 30 April 1997. This region encompasses a large part of the Western Arctic Ocean. The initial ice area covers ∼2.52 × 106 km2. At the end of April, this region covers ∼2.59 × 106 km2, a net divergence of ∼3%. Over the period, thin ice (0–20 cm) typically covers <2% of this area. The RGPS estimates only the thickness distribution of sea ice volume produced by openings and closings of the ice cover since the initial observation. Thus, only the ice volume of the seasonal ice cover can be determined. Between November 1996 and April 1997, ∼1000 km3 (∼0.4 m) of sea ice is produced. The amount stored in undeformed ice and ridged ice is dependent on the character of the redistribution function. The RGPS products also provide estimates of multiyear ice coverage. From the time‐series of multiyear ice coverage, we estimate that nearly 83% of the area is covered by multiyear ice. For more detailed examination of the regional dependence of ice‐cover deformation, volume production, and MY ice coverage, the larger region is divided into five subregions. Where possible, we provide an analysis of the errors in the above estimates. In cases where quantification of the uncertainty is not feasible, we list the potential error sources. There are remaining sources of uncertainty in these calculations that remain unquantified, but at this time, there are no adequate in situ or remote‐sensing data for comprehensive evaluation of the above estimates.