Annual and seasonal variation of sea surface salinity retrieved from NASA Aquarius satellite in the northwestern Pacific Ocean

Abstract:

Salinity plays an important role in driving ocean circulation and it is influenced by the interaction of atmosphere and ocean as well as sea ice and ocean. Despite of importance of salinity, the study on salinity analysis is limited due to sparse and lack of continuous observational data. Recently, global observation of salinity based on satellite is contributing to various fields such as salinity variability, interaction between atmosphere and salinity, and data assimilation to numerical model. It is necessary to evaluate the accuracy of salinity which is retrieved from satellite using in situ observation data. This study evaluates the accuracy of salinity retrieved from NASA Aquarius satellite during year 2012 to 2014 and investigates the annual and seasonal variation of salinity during observation period. And, we seek for the mechanism of salinity variability from rainfall. Salinity of Aquarius observation in the low-latitude is underestimated, while it is overestimated in the high-latitude. The difference of salinity between in situ (Argo) observation and satellite is about 0.5-0.6PSU in the low-latitude, and it shows over 1.0PSU in the high-latitude. Salinity distribution in the subtropics increases during year 2013 and 2014 than year 2012. In addition, salinity represents seasonal variability with maximum during the March-June and minimum during August-September in the northwestern Pacific region. Salinity distribution is consistent with rainfall distribution. Spatial distribution of salinity and comparison with rainfall observed from TRMM satellite will be presented at the conference.