Satellite passive microwave measurements of sea ice concentration: an optimal algorithm and challenges
Abstract. Sea ice concentration has been measured globally with satellite microwave radiometers for over 30 years. However there is still a need for better understanding of corresponding challenges and consequently identifying an optimal method for sea ice concentration retrieval suitable for climate monitoring. The method should minimize inter-sensor calibration discrepancies and sensitivity to error sources with climatic trends (e.g. atmospheric water vapour and water surface roughening by wind). This article presents the results of an extensive algorithm inter-comparison and validation experiment. Thirty sea ice algorithms entered the experiment where their skills were evaluated over low and high sea ice concentrations, thin ice and areas covered by melt ponds. In addition, atmospheric correction of input brightness temperatures and dynamic tie-points approach were suggested. A selection of thirteen algorithms is shown in the article to demonstrate the results. Based on the findings, an optimal approach was suggested to retrieve sea ice concentration globally for climate monitoring purposes.