Classification of Interannual Surface Layer Salinity Variability

Since surface layer salinity (SLS) mainly reflects sea surface freshwater flux and affects ocean circulation and upper ocean stratification by modifying seawater density, knowledge of SLS variability is important to better understand the global hydrological cycle and ocean and climate variability. The global pattern of SLS interannual variability has not received as much attention compared to the seasonal variability. The SLS interannual variability in the global ocean based on Argo profiling float data over 2003-2020 was classified into seven individual clusters. SLS interannual variability was found to be regionally different even within each ocean basin and primarily corresponded to large-scale climate mode variability. The spatial distribution of the classified SLS clusters provides the first map of SLS interannual variability in the global ocean that largely reflects the variability of the global hydrological cycle.