Vertical structure analysis of ocean temperature and salinity using depth series EOF method with argo data

How to analyze, interpret and make use of marine big data has become a serious challenge to the geophysical community. A statistical technique vertical EOF (VEOF) is introduced to extract vertical pattern of the ocean. To explore the ocean environment with untraditional EOF method, which the depth series are used to replace time series in traditional analysis, allowing the vertical spatial patterns of oceanic variables to be revealed. Using the Argo dataset from 2004 to 2016, we analyze the vertical variations of temperature and salinity in the global ocean. The results show that the first VEOF modes exhibit coherent signatures with the vertical average of temperature and salinity which reveal that the first mode is climatology mode. We conduct the temperature seasonal VEOF analysis and consider that the second mode of VEOF is related with the thermocline and halocline. The comparison of the barrier layer thickness (BLT) pattern with the third mode of VEOF in the tropical Pacific Ocean shows that the third mode is associated with local heat transfer. The second mode possible results from the external heat transfer, while the third pattern is possible caused by the internal heat transfer according to phase change of the depth series.