Abstract
This paper describes the development of the current version of the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) algorithm that is used to estimate snow depth for the Japan Aerospace Exploration Agency. The algorithm uses native resolution brightness temperature observations, except for the 89GHz channel which is resampled to the 36GHz footprint, with brightness temperature corrections made on the native measurements rather than using the aggregated brightness temperature observations. A shallow snow detector is developed using the 89GHz channels to detect shallow snow. Furthermore, algorithm retrievals are comprised of the sum of a forested component and a non-forested component with a dynamic estimation of snow depth related to snowpack evolution from selected polarization differences. When compared with up to 254 individual ground station measurements of snow depth, tests show that the new algorithm performs better than previous static parameterized versions both in overall terms and in terms of low to moderate fractional forest cover. For dense forest cover, the algorithm is similar in performance to the previous version. Bias improvements are also very encouraging, but further work is still required to improve the new algorithm's performance in overall error terms and for different fractional landcover mixtures.
