Multidecadal Change of the Mindanao Current: Is There a Robust Trend?

Abstract

AbstractTen ocean state estimate products are analyzed to quantify the multidecadal change of the Mindanao Current (MC). These data sets suggest multidecadal trends of the MC transport since 1961, 1980, and 1993 are weak (‐0.3 Sv, +0.7 Sv, and +2.1 Sv, respectively; 1 Sv ≡ 106 m3/s) and not robust with respect to the large spread of different data sets. The primary cause is the discrepancies in different wind data sets, and change of the North Equatorial Current's bifurcation latitude also acts to attenuate the MC change. The bifurcation latitude shifts southward (northward) under enhanced (weakened) northeasterly trade winds and feeds less (more) water to the MC. Experimental simulations of a reduced‐gravity model forced by reanalysis and model‐projected wind trends suggest an asymmetry of the MC's response to wind forcing. Anomalous westerly winds in the western Pacific can dramatically enhance the MC through spinning up the cyclonic local recirculation.