Long-term remote sensing of total suspended matter using Landsat series sensors in Hulun Lake, China

The water clarity of many inland water bodies in the Inner Mongolian Plateau of China is under threat due to intensifying land use pressures and climate variability. Total suspended matter (TSM), one of the main factors determining water clarity, is a parameter that can be remotely derived. Two data-gathering expeditions were conducted in Hulun Lake, the largest inland lake of this plateau, in 2013 and 2015. Based on the in situ TSM data, we evaluated commonly used TSM algorithms that can be applied to Landsat images. The algorithm using the single near infrared (NIR) band had the best performance. Time series of TSM maps of Hulun Lake from 1986 to 2017 were obtained applying this algorithm to 258 cloudless Landsat images and the relationship of TSM to water level, water area, precipitation, and wind speed were analysed. We found that annual mean TSM was negatively correlated with water level and water area, with R2 of 0.46 and 0.60, respectively; TSM was positively correlated with precipitation and wind speed, with R2 of 0.32 and 0.34, respectively.