Atmospheric and oceanic processes in the vicinity of an island strait

Our research synthesizes observations and modeling (including real-time coupled) to understand the role of various forcing factors in the evolution of the flow through the Mindoro Strait in the Philippines. A flow reversal occurred between two intensive observing cruises (sponsored by ONR as part of the PhilEx DRI). High resolution (~1-3 km) air/sea model simulations using the Navy's Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS) capture the flow reversal and agree with measured currents from two moorings in the vicinity of Mindoro Strait. The contributing factors include wind, eddies, and stratification. A short (25-27 January) easterly monsoon surge and a longer (8-20 February) northerly surge are represented in the model as well as in Quikscat and underway wind data taken during the cruises. Placement of the surge-enhanced mesoscale eddies off Mindoro (Pullen et al., 2008) may also influence flow reversal, and were intensively sampled during the first cruise based on guidance from the forecast model. In addition, a small eddy occupies Mindoro Strait during the flow transition, and is an intermittent feature at other times. Enhanced upper ocean stratification in winter 2008 due to anomalous precipitation created more layered flow as evidenced by CTD data, and served to isolate the surface circulation. The relative role of these various factors in the unfolding of the flow reversal is examined.