Analysis of Climate - Sea Ice Interactions in the Polar Basin using Remote Sensing Imagery and Atmospheric Diagnostics

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Research on the impacts of climate change and variability in polar regions focuses on the interactions between the polar sea ice and climate systems. In particular, more than thirty years of passive microwave imagery of almost daily coverage of the polar regions is used to determine sea ice concentration and ice motion. Upper air reanalysis data from the European Centre for Medium-Range Weather Forecasts are used to determine synoptic patterns of geopotential height and temperature as well as derived fields of vorticity and ageostrophic motion. In addition, radiation balance data are available. Statistical models are used to find associations in time and space that may provide insight into the formative processes in the Arctic. From the field of hyperspectral image analysis, the concept of the spectral mixture model has been used to derive spectral signatures of surface characteristics. We have developed the concept to apply to temporal signatures of sea ice concentration in order to identify specific seasonal profiles of ice coverage for specific regions. We are now applying this to the Passive Microwave Radiometer data to rank the years of decreasing ice extent for specific regions defined by the temporal mixture analysis to determine what regional disparities exist in the warming of the past eight years. This can be compared with similar WMO ranking of temperatures by region to provide insight into the role of atmospheric warming in the regional disparities. A second new line of inquiry is analysis of the date of spring melt by looking at the change in the variance structure of the daily ice anomalies in various regions. Initial work in the Beaufort Sea and Lancaster Sound areas show promise. The analysis of the temporal change in variance is also applied to the data for the radiation components from the ECMWF reanalysis and there are interesting associations between sea ice and the patterns of the components of the solar and thermal radiation fluxes for the surface. We have also examined the daily progression of synoptic patterns of geopotential height, temperature, vorticity etc. associated with the onset of melt to assess the circulation forcing in conjunction with the radiation anomalies.