Digital Processing of Passive Ka-Band Microwave Images for Sea-Ice Classification

摘要

The primary objective of NORDA's Ka-band Radiometric Mapping System (KRMS) program is to provide basic research needed for Navy development of an operational imaging system that can produce detailed information concerning ice conditions over broad regions of the Arctic. To this end, methods suitable for automated identification and classification of sea ice types and open water are being developed. An experimental plan has been formulated that will lead to an automated system that will provide real-time ice classification information onboard Navy aircraft. This report represents completion of the initial state of this plan. During March 1983 extensive high-quality KRMS imagery and coincident high-resolution photography were obtained of ice in the Beaufort Sea. Analysis of these data suggests that four classes of winter surfaces can be distinguished solely on the basis on Ka-band brightness temperature: open water, frazil, old ice, and young/first year ice. New ice (excluding frazil) and nilas display brightness temperatures that overlap the range of temperatures characteristic of old ice and young/first year ice. Scenes in which new ice or nilas are present in appreciable amounts are subject to substantial errors in classification. Textural characteristics of nilas and new ice, however, differ significantly from textural features characteristic of other ice types and probably can be used with brightness temperature data to classify single-band microwave images.