The homogeneity study of the sea surface temperature data along the coast of the China Seas

Abstract

The monthly sea surface temperature (SST) data of 27 marine observation stations have been detected and adjusted by the Penalized Maximal T test (PMT) and the detailed metadata archive. In this study, the homogenous surface air temperature (SAT) data from neighboring meteorological observation stations are used to construct the reference series by correlation coefficient weighted averaged method. Results show that almost all of the stations along coast of the China Seas, the inhomogenities or change points can be detected. Combined with the detailed metadata of each station, the main reasons causing the inhomogenization problems are instrument change (including the change from artificial observation to automations) and relocation, accounting for about 52.4% and 33.3% of the total change points. It is also found that the annual mean SST trend has changed obviously and homogeneity is improved well after adjustment. The warming rate of SST series along the coast of the China Seas after adjustment is much larger than that before adjustment. This phenomenon links tightly to the SST decreasing after automation which leads to the large proportion of negative correction values.