STATISTIC DISTRIBUTIONS OF MICROWAVE BRIGHTNESS TEMPERATURE OF SEA ICE IN THE MOS-1 AIRBORNE VERIFICATION EXPERIMENT

• Main Authors: オカモト ケンイチ, アワカ ジュン, Ken'ichi OKAMOTO, Jun AWAKA
• Format: Report
• Language: English
• Published: ABSTRACT 1987
• Subjects: Polar meteorology and glaciology; Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology; Sea ice
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3546; http://id.nii.ac.jp/1291/00003546/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3546&item_no=1&attribute_id=18&file_no=1

Microwave brightness temperatures of sea ice were observed off the coast of Monbetsu on January 25 in 1985 by the airborne 23- and 31-GHz microwave radiometers in the MOS-1 airborne verification experiment. Sea ice map and surface temperature data of sea ice measured by a helicopterborne radiative thermometer were supplied by the Maritime Safety Agency and were used for the ground truth data. Histograms were produced to show statistic distributions of microwave brightness temperatures at 23 and 31GHz. Remarkable differences were not found between histograms at 23 and at 31GHz. Cumulative distribution tables show that microwave brightness temperatures of more than 50% took values higher than 232 and 234K at 23 and at 31GHz, respectively. If the average surface temperature value of sea ice, 258K, is used, microwave emissivity values become larger than 0.9 at 23 and 31GHz for sea ice of more than 50%. Emissivity value suggests that the greater part of observed sea ice was composed of young ice and thin first year ice. This result is consistent with the ground truth data. It was verified in this experiment that microwave radiometers of 23 and 31GHz are useful for observing sea ice.