Mapping the Coastal Upwelling East of Taiwan Using Geostationary Satellite Data

Coastal upwelling is important for coastal ecosystems and the blue economy because of its large productivity and large potential for catching fish. However, coastal upwelling along the Taiwan east coast has received little attention from the research community. This study used five-year daily Himawari-8 geostationary satellite sea surface temperature data to map the coastal upwelling east of Taiwan during the summer monsoon season. We applied a semi-automatic image process technique based on the topographic position index for the quantitative upwelling mapping. The results show clear evidence of seasonal coastal upwelling along the entire Taiwan east coast, mainly under the influence of upwelling-favorable southwesterly/southerly winds. There are three broad upwelling centers along the Taiwan east coast: north, central, and south. The upwelling around the northern center has the longest upwelling season, lasting from May to September. The upwelling extents are larger between June and August during the height of the summer monsoon.

Automated summary

This study used satellite data to map and quantitatively analyze coastal upwelling along the Taiwan east coast during the summer monsoon season, showing evidence of seasonal upwelling influenced by southwest/south winds. The results indicate three broad upwelling centers in the north, central, and south, with the northern center having the longest upwelling season lasting from May to September, and larger extents between June and August during the peak of the summer monsoon.