Surface suspended particulate matter concentration in the Taiwan Strait during summer and winter monsoons

Abstract

The Taiwan Strait (TS), situated between Taiwan and China, is shallow, relatively turbid, and characterized by strong tidal currents and winter and summer monsoon seasons. The aim of this study was to use images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Aqua satellite to investigate how local sediment sources in addition to the seasonality in wind, oceanographic currents, and waves influence the suspended particulate matter (SPM) dynamics in the TS. In winter, northeast (NE) winds drive the China Coastal Current southward. Cold water with a high SPM concentration is transported southward into the Strait. After the highest SPM concentration reaches its peak in December and January, the winds weaken and the SPM concentration decreases. During summer, winds are less strong and SPM concentration is lower. Although typhoons typically occur in summer, they generate only a weak signal in the surface SPM concentration data from MODIS because of the low number of cloud-free images during these periods. Typhoons result in a short-term increase in the SPM concentration but do not strongly influence the seasonal values in the satellite-derived SPM concentration maps.