National Oceanic and Atmospheric Administration Soil Moisture Operational Product System: An overview and data assimilation applications

Abstract

National Oceanic and Atmospheric Administration–National Environmental Satellite, Data, and Information Service (NESDIS) developed the Soil Moisture Operational Product System (SMOPS) to serve as a one‐stop shop for all available microwave satellite soil moisture observations. SMOPS also offers a blended data layer by combining soil moisture retrievals from single sensors. Through the effort over the past two decades, the SMOPS has operationally produced near real‐time (SMOPSnrt), climate data record (SMOPScdr), and high‐resolution (SMOPShr) products. To provide a comprehensive overview of the major characteristics and features of SMOPS datasets, this paper introduces the SMOPS architecture, outlines the evolution procedure, and highlights the key areas of development focused on by NESDIS. A review of the most recent progress shows that the quality of 25 km SMOPScdr and SMOPSnrt is comparable with the Soil Moisture Active and Passive (SMAP) product. Using SMAP as a benchmark ensures SMOPS products purely dependent on satellite observations, while the machine learning models incorporated in the SMOPS system ensure the independent from SMAP. As such, SMOPS can still offer superior quality of historical and near real‐time products when SMAP is not available. Because users require continuous data and welcome resolution enhancement for their high‐resolution model research and operational applications, the SMOPShr has been developed by downscaling SMOPScdr with a machine learning model. The preliminary evaluations indicate that SMOPShr and SMOPScdr exhibit satisfactory consistency, while SMOPShr provides more detailed spatial information. This paper introduces SMOPS to the community and encourages user engagement in shaping its future development.