Intercomparison of Global Sea Surface Salinity from Multiple Datasets over 2011–2018

Abstract

The variability in sea surface salinity (SSS) on different time scales plays an important role in associated oceanic or climate processes. In this study, we compare the SSS on sub-annual, annual, and interannual time scales among ten datasets, including in situ-based and satellite-based SSS products over 2011–2018. Furthermore, the dominant mode on different time scales is compared using the empirical orthogonal function (EOF). Our results show that the largest spread of ten products occurs on the sub-annual time scale. High correlation coefficients (0.6~0.95) are found in the global mean annual and interannual SSSs between individual products and the ensemble mean. Furthermore, this study shows good agreement among the ten datasets in representing the dominant mode of SSS on the annual and interannual time scales. This analysis provides information on the consistency and discrepancy of datasets to guide future use, such as improvements to ocean data assimilation and the quality of satellite-based data.

Weakening Trend of Luzon Strait Overflow Transport in the Past Two Decades

“…Bimodal harmonic analysis (Liu & Wei, 2021) shows that the annual cycle of OBP anomaly at 19 and 20°N is nearly isochronous, whereas at 21°N the annual cycle of OBP anomaly is significantly different (Figure 1d). This implies the presence of a larger transport anomaly in the northern strait than that in the southern strait.…”

Early detection of anthropogenic climate change signals in the ocean interior

“…The correspondence between AMOC strength and western subtropical Atlantic salinity aligns with evidence from the marine sedimentary record 45 , and is explained by trapping/advection of salt during periods of weak/strong AMOC. While many surface salinity observations are gathered using thermosalinographs on VOS and research vessels 46 , these are not as far as we are aware 47 , regularly compiled into global quality controlled databases, such as done with the surface ocean in SOCAT 48 for instance. Instigating such an effort seems highly worthwhile given the results presented here.…”

Opposite‐Sign Sea Surface Salinity Anomalies Over the Northeastern and Southwestern South Atlantic Ocean From 2010 to 2017

“…The spatial distribution of interannual SSS variations (Figure 1c) is consistent with Liu and Wei (2021, their Figure 11a), where the largest magnitude of variance occurs over the Congo and La Plata River mouths. Liu and Wei (2021) also showed that the leading mode of interannual SSS variations is an east-west opposing pattern in the South Atlantic Ocean, with centers occurring over the two major river mouths. However, their study mainly focused on the intercomparison of SSS variations based on 10 different data sets, and the mechanism for the opposite-sign SSS anomalies was not identified.…”

“…As a result, knowledge of SSS variability is critical to understanding ODY and climate changes. Despite the increased research on identifying SSS variability over the global ocean (e.g., Guan et al., 2019; Li et al., 2016; Liu & Wei, 2021), the SSS variations in the South Atlantic Ocean and especially their interannual components are not well understood.…”