The Upwelling in the Region between Java and Australia during the South-East Monsoon

Abstract

An examination of the oceanographic conditions in the region between Java and Australia during the south-east monsoon season shows that the main upwelling area in this region is situated along the coast of Java and Sumbawa, and not along the north-west Australian shelf, as was previously assumed. The amount of upwelling south of Java is estimated to contribute 2.4 million m³/sec to the South Equatorial Current and the upwelling velocity is of the order of 50 × 10^-5 cm/sec. The region is characterized by very high concentrations of inorganic phosphate at the bottom of the euphotic layer and by a high plankton biomass. The transparency of the water in the upwelling area is low, indicating a high concentration of suspended matter. The possible development of the upwelling during the north-west monsoon season is discussed.