Evaluation and Intercomparison of SMOS, Aquarius and SMAP Sea Surface Salinity Products in the Arctic Ocean

Severine Fournier, JPL/NASA/Caltech, Pasadena, CA, United States, Tong Lee, JPL, Pasadena, United States, Wenqing Tang, Jet Propulsion Laboratory, Pasadena, CA, United States, Michael Steele, Univ Washington, Seattle, United States and Estrella Olmedo, Barcelona Expert Center, Institute of Marine Sciences, CSIC, Physical and Technological Oceanography, Barcelona, Spain
Abstract:
The Arctic Ocean freshwater content and distribution are changing due to the combined effects of river runoff, precipitation, sea ice melt, and wind-driven ocean circulation. These changes can impact the North Atlantic Ocean circulation and the related transports of heat, freshwater, carbon, and nutrients that have potential influence on climate, weather and water and biogeochemistry cycles. It is thus of importance to study the Arctic Ocean freshwater changes.

Currently, there are many obstacles to understanding the Arctic freshwater system. Because about 1/3 of the freshwater discharge from land to the Arctic ocean is not directly measured, there is a substantial uncertainty in the total flux of freshwater from land to the Arctic ocean. Modelling tools have been widely used, however, the sparse in situ data coverage (in time and in space) limits our knowledge and model representation of the changing freshwater patterns and pathways. Sea surface salinity (SSS) observations from the NASA Aquarius/SAC-D satellite, the NASA Soil Moisture Active Passive (SMAP) and the ESA Soil Moisture and Ocean Salinity (SMOS) missions now provide unprecedented mapping capabilities at improved spatiotemporal resolution. Nevertheless, these measurements are subject to relatively large uncertainties in high-latitude oceans due to the poor sensitivity of the L-band sensors to salinity in cold-water environment. However, Arctic SSS changes are large and recent studies have demonstrated potential capabilities for satellite SSS observations at high latitudes.

In this work, we present an assessment of the quality of the different satellite SSS products against multiple in situ datasets and we provide an intercomparison of these different satellite SSS products. We use several “popular” satellite SSS products including the LOCEAN debiased v3 SMOS, the BEC v2 SMOS dedicated to the Arctic Ocean, the Aquarius v5, the Aquarius CAP v5, the SMAP RSS v3 and the SMAP JPL v4.2 SSS products.

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