Spatiotemporal Variability of Chlorophyll a and Sea Surface Temperature in the Northern South China Sea from 2002 to 2012

Eleven-year time series data gathered by the moderate- resolution imaging spectroradiometer ( MODIS) for chlorophylla ( Chl- a) and sea surface temperature ( SST) were collected. Empirical orthogonal function ( EOF) decomposition and kriging interpolation were applied to capture the main variations of Chl- a and SST. The results showed that Chl- a and SST exhibited four basic patterns: ( i) Chl- a and SST were relatively well correlated ( R-2 = 0.48) and had a converse season cycle. ( ii) The coastal regions were characterized by high Chl- a concentrations and low SST, whereas the open sea area had relatively low Chl- a concentrations and high SST. ( iii) Chl- a and SST showed a seasonal pattern for almost every category. In summer, Chl- a concentrations were relatively low (< 0.2 mg center dot m(-3)) and SST was high (> 27 degrees C); in spring and autumn, Chl- a concentrations and SST were dominated by values of 0.1- 0.2 mg center dot m- 3 and 25- 29 degrees C, respectively; in winter, Chl- a concentrations were relatively high ( 0.2- 0.4 mg center dot m- 3), and SST was low (< 27 degrees C). ( iv) The EOF mode for the variations in Chl- a and SST in the northern South China Sea ( SCS) regions accounts for approximately two thirds of the total variance. This study demonstrated that the EOF could provide a preliminary quantification of synoptic Chl- a and SST distributions.