THE NEW GUINEA COASTAL CURRENT AND UPWELLING SYSTEM: SEASONAL VARIABILITY INFERRED FROM ALONG-TRACK ALTIMETRY, SURFACE TEMPERATURE AND CHLOROPHYLL

摘要

The New Guinea Coastal Current (NGCC) is part of the Low Latitude Western Boundary Current system of the South Pacific connecting subtropical to equatorial waters. The variability of this narrow along-coast surface current is investigated using cross-track geostrophic current anomaly derived from five altimetric tracks that are orthogonal to the coast. Satellite SST and chlorophyll data give information on the associated surface chlorophyll and SST patterns. The NGCC forms a coherent vein from Vitiaz Strait to the northern New Guinea tip that varies mainly at annual timescale. Annual variations are correlated with the monsoonal wind reversal. During austral winter, the NGCC flows northwestward, advecting cool water (<28°C) from the Solomon Sea along the coast, whereas during summer the coastal upwelling drives a positive along track SLA slope and a southeastward NGCC. The upwelling is characterized by cool SST (<28.5°C) and elevated chlorophyll (>2 mg m~(-3)).