High Resolution Automated Sea Ice Cover Analysis

The 25.4 km automated sea ice algorithm already operational in NCEP, based on the NASA-Team SSMI algorithm, has permitted a number of improvements in sea ice products within the NWS. Certain features of interest, however, such as the Great Lakes, other large North American lakes, and the ice edge, are not managed well at this resolution. SSMI carries a higher resolution channel, at 85 GHz, which is capable of 12.7 km resolution. A significant obstacle to implementing a high resolution automated analysis has been that most of the algorithms already available in the literature either rely on lower resolution channels as well, or cannot be run entirely without human intervention. We therefore have developed an algorithm which can be run in an entirely automated fashion. Due to the sensitivity of the 85 GHz channel to weather effects, this also required an improved, automated, weather filtering procedure. It was also required that the algorithm correspond to the currently operational insofar as possible, on the grounds that a substantial body of experience already exists based on the extant algorithm, and a desire to avoid introducing artefacts to time series derived from the NCEP analyses. The resulting weather filter is easily applicable to concentrations derived from other algorithms.