Author(s): Margaret A. Knuth; Stephen F. Ackley
Linked Author(s): Stephen Ackley, Margaret Knuth
Keywords: No Keywords
Abstract: In situ sea ice data taken from a Dec 1999-Feb 2000 cruise aboard the RVIB Nathaniel B. Palmer is compared with Special Sensor Microwave/Imager (SSM/I) satellite data from the same period. The in situ data comes from analysis of helicopter video covering over 18,000 km (track line) of the Ross Sea and from shipboard observations taken throughout the cruise. The ship measurements showed a complex of thick (3m) multiyear large floes with 1m thick snow and first year floes of thinner ice (<1.5m) with less, but still substantial snow covers (0.2-0.4m). Sea ice concentrations from both the Bootstrap and NASA Team Algorithms are used here for comparison. Previous work has suggested possible errors in estimating concentration, especially in summer, from microwave satellite data. Our objectives include attempted validation, with quantifiable errors, of these two widely used techniques to convert passive microwave data to ice concentrations in summer, using the helicopter video data base as the comparison data. We found that only 50% of the variance in video summer ice concentration is explainable by the passive microwave satellite data. Further, the passive microwave has the troubling nonstationary characteristic of overpredicting concentration at low concentrations and underpredicting ice concentration at higher video concentrations.
Year: 2004