Li, W.K.; Tian, L.Q.; Li, J.; Zhou, Q.; Li, Y., and Li, S., 2019. Impact of natural and anthropogenic changes on the spatial–temporal variations of total suspended matter in the Pearl River Estuary, China. In: Jung, H.-S.; Lee, S.; Ryu, J.-H., and Cui, T. (eds.), Advances in Remote Sensing and Geoscience Information Systems of Coastal Environments. Journal of Coastal Research, Special Issue No. 90, pp. 66-76. Coconut Creek (Florida), ISSN 0749-0208.
The Pearl River Delta and its adjacent coastal water is one of most developed regions of China, and high variability in its environment has been observed due to its subtropical monsoon climate as well as high-intensity human activity. This study aims to interpret the spatial–temporal variations of total suspended matter (TSM) in the Pearl River Estuary (PRE) and its driving factors. An empirical band ratio TSM retrieval algorithm was developed using Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua images and in situ data. The coefficient of determination (R2) and mean relative error (MRE) of the algorithm are 0.925 and 15.67 %, respectively. Significant spatial and temporal (seasonal and inter-annual) TSM variations were revealed from 2003 to 2015, which were found to gradually decrease from the western mouths of the river to its central. The monthly mean TSM was higher in winter than in summer, with a peak concentration of 33.2 mg/L in December and a low of 16.4 mg/L in August. Wind is a main driving force of TSM spatial–temporal variation, and sediment yield of the river and tide also play positive roles. Meanwhile, dam construction in the Pearl River Basin (PRB) was found to be crucial for decreasing sediment yield, and sediment yield become the main factor when the average wind speed was steadily decreased. Moreover, the uncertainty from limited Landsat observations was assessed using MODIS data, which demonstrated that the MRE was about –50 % and 50 % during most of the year, and thus higher frequency observations are required. These results gave an environmental basis for the optimized development and management of rivers and estuary in the PRB and the PRE.