Development of a global operational snow analysis at the US Air Force 557th Weather Wing

This study presents the development of a global operational snow analysis at 10-km resolution, called US Air Force Snow and Ice Analysis (USAF-SI). The USAF-SI features several major advances relative to the USAF 557^th Weather Wing (WW)’s current Snow Depth Analysis Model (SNODEP). SNODEP is a daily global snow analysis of snow (over land) and ice (over water) at 25-km resolution and is crucial for use by numerous other 557^th WW programs and external customers. The operational SNODEP is currently estimated by using the Defense Meteorological Satellite Program (DMSP) F-16, F-17, and F-18 Special Sensor Microwave Imager/Sounder (SSMIS) and synoptic observations. USAF-SI incorporates four major enhancements over the SNODEP. First, the outdated SNODEP snow depth retrieval algorithm is replaced by the Foster et al. (1997; 2005) approach, which considers the effects of variations in forest cover. Second, the simple blending algorithm for SSIMS-based snow depth estimates and synoptic observations is replaced by the Bratseth scheme, a successive correction algorithm that converges to the solution provided by Optimal Interpolation (OI). Third, outdated quality control datasets are updated and quality control algorithms are reorganized to ensure the performance of the snow analysis. Lastly, the spatial resolution of snow and ice estimates are increased from 25-km to 10-km based on all of these improvements. USAF-SI are fully integrated into the global operational land analysis configuration at the USAF 557^th WW enabled by the NASA Land Information System (LIS). This presentation will include the results from the evaluation of USAF-SI snow depth against independent datasets and other currently available snow analyses from various operational agencies.