Position variability of the Kuroshio Extension sea surface temperature front

摘要

High spatial resolution sea surface temperature(SST) data from 1993 to 2013 are used to detect the position of the Kuroshio Extension sea surface temperature front(KEF) from 141°E to 158°E,and the seasonal,monthly and interannual-to-decadal variations of the KEF position are investigated.The latitudinal position of the KEF varies with longitudes:the westernmost part of the KEF from 141°E to 144°E is relatively stable,whereas the easternmost part from 153°E to 158°E exhibits the largest amplitude of its north-south displacement.In the light of the magnitudes of the standard deviations at longitudes,then the KEF is divided into three sections:western part of the KEF(KEFw,141°–144°E),central part of the KEF(KEFc,144°–153°E) and eastern part of the KEF(KEFe,153°–158°E).Further analysis reveals that the KEFw position is dominated by the decadal variability,while the KEFc and KEFe positions change significantly both on interannual and decadal time scales.In addition,the KEFw position is well correlated with the KEF path length.The possible mode leading to the decadal oscillation of the KEFw is further discussed.The KEFw position exhibits significant connections with the Pacific decadal oscillation(PDO) index and the north Pacific gyre oscillation(NPGO) index with a time lag of 40 and 33 months,respectively.