Variability of the Mindanao Current: Mooring observation results

Abstract

Mooring observations were conducted from October 1999 to July 2002 near the east coast of Mindanao Island, the Philippines, (6°50′N, 126°43′E) to observe current variability at the axis of the Mindanao Current (MC). The MC was a strong current with a subsurface velocity maximum exceeding 1.3 m s−1 at approximately 100 m depth. The MC flows shallower than 700 m, and there was no evidence of a steady northward current (the Mindanao Undercurrent) at the study location. Compared with the large average velocity, MC variability was low (standard deviation <0.2 m s−1 for all directions). All the observed interannual, seasonal, and intraseasonal variations in the MC were of comparable amplitude. The MC was strong during boreal summers and during the onset of the 2002–03 El Niño. The core velocity of the MC at approximately 100 m was correlated with the sea level difference between Cebu, Philippines and Malakal, Palau.