Sea Ice Data Derived from Microwave Radiometer for Climate Monitoring

A near real-time analysis of sea ice concentration (SIC) has been carried out using satellite observations by microwave radiometer: Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave/Imager (SSM/I). The NASA team algorithm is adopted to compute SIC from brightness temperatures by Microwave Imager. A correction is applied for the derived SIC to eliminate the effect of the spill over of land emission. Adjustment of SMMR SIC to that of SSM/I are realized by a method proposed by Cavarieli et al.(1999). In this analysis, ice shelvs are treated as 100% of SIC for a boundary condition of a weather prediction model at the Japan Meteorological Agency (JMA). Low SIC in summer remains in the analysis. The analysed SIC is merged into a historical sea surface temperature (SST) analysis named COBE-SST, translating SIC to SST by a quadratic function obtained statistically. Therefore consistency between SST and SIC is accomplished in the SST analysis. The abbreviation COBE denotes Centennial in-situ Observation Based Estimates of variability of SST and marine meteorological variables. The COBE dataset contains analyses and errors for the 20th century which are estimated statistically from observational data of the International Comprehensive Ocean and Atmosphere Data Set and the Kobe Collection. The both SIC and SST analyses are utilized in the Japan Re-Analysis for 25 years (JRA-25) and the JMA Climate Data Assimilation System (JCDAS) as boundary conditions of an atmosheric model.