Ice edge detection and ice/water classification utilizing the ERS-1 and TOPEX altimeters

The Naval Oceanographic Office Altimetry Data Fusion Center (ADFC) has a requirement to provide daily ice edge positions to the Navy/National Oceanic and Atmospheric Administration National Ice Center in Suitland, Maryland. These positions were provided operationally in 1987-88 during the GEOSAT mission. The GEOSAT altimeter-derived ice edge positions were based on an index of the ratio of two engineering parameters which are not available in either the ERS-1 Altimeter Fast Delivery Product or the TOPEX/POSEIDON data received by the ADFC. Therefore, algorithms had to be developed based on the parameters that were available, including wind speed, significant wave height, peakiness, and off-nadir pointing. Since there are advantages and disadvantages to using each of these parameters for ice detection, the algorithms employ a multiple parameter approach. Results of validation studies in which the altimeter-derived ice products were coupled to imagery show that the currently operating radar altimeters can be exploited for operational ice edge mapping.