Examining the potential of deriving sea ice concentration fields from enhanced resolution passive microwave imagery

Passive microwave imagery is useful for deriving sea ice concentration fields because of its all-sky capabilities, and it has provided a near-continuous forty-year climate record of sea ice conditions. However, the low spatial resolution (25-50 km) of the historically available imagery limits the spatial detail that can be observed and yields relatively low precision estimates of the ice edge. This is not optimal for operational support, nor can it provide accurate information on small-scale processes such as lead and polynya formation. A new enhanced passive microwave brightness temperature climate record has been produced that yields gridded resolutions up to 3.125 km, substantially higher than the standard 25 km resolution gridded products. We apply the enhanced resolution brightness temperatures to derived gridded sea ice concentration fields. We compare the enhanced resolution fields with the standard resolution products and find that significantly more detail in the ice pack is obtained, and a clearer, more precise ice edge is delineated. We also find fewer issues with land-spillover effects where grid cells with a mixture of land and ice-free ocean are interpreted by the concentration algorithm to be false coastal sea ice. The results indicate that using the enhanced resolution brightness temperatures has the potential to substantially improve the sea ice concentration climate data record, extend the utility of the product to smaller-scale processes, and potentially provide more useful operational support than has previously been possible from passive microwave data.