SEA ICE GEOPHYSICAL MEASUREMENTS FROM SEASAT TO THE PRESENT,WITH AN EMPHASIS ON ICE MOTION: A BRIEF REVIEW AND A LOOK AHEAD

摘要

NASA launched Seasat in June 1978 carrying a remarkable arrayrnof microwave instruments designed to observe the global oceans,rnincluding an active microwave altimeter, scatterometer, and SARrnalong with a passive microwave radiometer. While the satelliternmission ended abruptly in mid-October 1978 after only about 100rndays of operation, unique and comprehensive views of the oceansrnwere obtained that clearly showed the extraordinary scientificrnvalue of the instruments by improving the knowledge of thernoceans circulation, wind and wave field, and characterization ofrnkey aspects of the cryosphere. Aside from optical and thermalrnsensor data, this data set from 25 years ago essentially set thernstage, providing a legacy if you will, for most of the majorrndedicated ocean satellite missions that have taken place since andrnare planned for the near future.rnIn this paper, we provide a short review of sea ice measurementsrnstarting from Seasat Seasat, including sea ice motion, the seasonal meltrncycle, ice extent and concentration, and estimates of thicknessrnfrom the proxy measurements of ice type and age and morerndirectly from freeboard. We end with a brief discussion on howrnthese measurements might be improved in the future.