Interannual variability of thermal front west of Luzon Island in boreal winter

Abstract

Interannual variability of thermal front west of Luzon Island during the winter of 1993–2013 is examined with the method of singular value decomposition (SVD) and a suite of satellite measurements in this paper. It is found that both the area and intensity of the thermal front west of Luzon Island show apparent interannual variability. Further study based on SVD shows that the interannual variability of the thermal front is highly associated with El Nino and Southern Oscillation (ENSO), and the correlation coefficient between Nino3.4 index and the first Principal Component (PC1) of thermal front can reach–0.65. The mechanism can be described as follows. In El Nino (La Nina) years, the East Asian winter monsoon (EAWM) is weakened (enhanced), inducing weaker (stronger) local wind stress curl (WSC) west of Luzon Island, and resulting in weakened (enhanced) Luzon cold eddy, which finally leads to the weakening (enhancement) of the thermal front.