How Well Does SMOS Depicts Decadal Trends of Sea Surface Salinity in the Global Ocean?
Abstract
Sea surface salinity (SSS) is a critical parameter linking the ocean with the water cycle. Sustaining and enhancing SSS observing system is therefore important for studying ocean-water cycle linkages. ESA's SMOS and NASA's Aquarius and SMAP satellite missions have pioneered global synoptic measurements of SSS from space. In particular, SMOS has reached a major milestone by providing a decade of satellite SSS measurements. Previous studies have documented SMOS' ability to characterize SSS variability from synoptic to interannual time scales. However, the fidelity of SMOS SSS in depicting decadal trends has not been documented. Here we compared the linear trends of SMOS SSS during the 2010s with those estimated from two in-situ based products. SMOS SSS are able to capture the large-scale trends in the tropical to mid-latitude oceans depicted by the in-situ products. SMOS SSS characterizes sharper spatial gradients of the trend patterns in the tropical Pacific and Atlantic Oceans, especially near the Intertropical Convergence Zone. This is believed to result from the much better spatial sampling of SMOS than in-situ measurements. SMOS SSS and the two in-situ products all reveal large-scale freshening over much of the tropical Pacific Ocean and salinification in the southeast tropical-subtropical Indian Ocean. Moreover, SMOS SSS show that the latter is associated with a salinification in the South China Sea and maritime continent region where in-situ measurements do not have sufficient sampling and coverage. The relationships of the decadal trends of SSS and changes in oceanic evaporation-precipitation will be discussed. SMOS SSS trends in the subpolar North Atlantic and Pacific Oceans are inconsistent with those estimated from the in-situ products, highlighting the need to improve calibration and retrieval algorithm and to develop technology innovation for the next-generation salinity-measuring satellites.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMGC095..04L
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGE;
- 1655 Water cycles;
- GLOBAL CHANGE;
- 1836 Hydrological cycles and budgets;
- HYDROLOGY;
- 4215 Climate and interannual variability;
- OCEANOGRAPHY: GENERAL