Comparison of thin ice thickness distributions derived from RADARSAT Geophysical Processor System and advanced very high resolution radiometer data sets

Abstract

Thin ice thickness distributions estimated from advanced very high resolution radiometer (AVHRR) and RADARSAT Geophysical Processor System (RGPS) data sets were compared over the Beaufort Sea and the Canada Basin for the period December 1996 to February 1997. The comparisons show a compelling agreement. High correlations were found in cases where thin ice grew in large, wide leads extending several hundred kilometers. At these large scales, estimates from AVHRR images and RGPS showed similar amounts of thin ice in leads. However, when major surface deformation occurred on small scales (100 m to 10 km), the finer spatial resolution (100 m) of RADARSAT images enabled the RGPS algorithm to derive more thin ice than that of AVHRR. Under such conditions the correlation between the two dropped, and a small negative bias (about 1%) was observed in the estimates from AVHRR. This bias, mostly concentrated at the very thin end of the thickness distribution, caused a further deficit in the AVHRR‐derived thin ice growth, roughly 0.2 cm/d. Although the AVHRR and RGPS algorithms treat snowfall differently in the ice thickness calculations, both snow assumptions appear reasonable. However, RGPS may underestimate the thin ice production because of the 3‐day sampling interval. With a better understanding of the sources of uncertainty and improved satellite estimates, a combination of these two satellite data could offer a wider coverage of thin ice thickness observations in the Arctic Basin.