A 1DVAR-Based Snowfall Rate Algorithm for Passive Microwave Radiometers

Abstract

This chapter introduces an overland snowfall rate algorithm for passive microwave radiometers. It relies on an embedded algorithm to detect the presence of snowfall. The retrieval of cloud properties is the foundation of the snowfall rate algorithm and is accomplished with a one-dimensional variational (1DVAR) model. The snowfall rate derived with the physical algorithm is further adjusted based on calibration against a ground radar and gauge combined precipitation product. Both the snowfall detection and the snowfall rate algorithms have been validated respectively against ground observations and radar and gauge combined analyses from the contiguous United States with satisfactory results. Specifically, the correlation coefficient of the validation data with the radar analyses reaches 0.50. Currently, the snowfall rate product is operationally generated at near real-time at the US National Oceanic and Atmospheric Administration.