Long-term remote monitoring of total suspended matter concentration in Lake Taihu using 250 m MODIS-Aqua data Kun Shi a , Yunlin Zhang a, ⁎, Guangwei Zhu a , Xiaohan Liu a,b , Yongqiang Zhou a,b , Hai Xu a , Boqiang Qin a , Ge Liu c , Yunmei Li c a Taihu Lake Laboratory Ecosystem Research Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China b University of Chinese Academy of Sciences, Beijing 100049, China c Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210046, China abstract article info Article history: Received 13 October 2014 Received in revised form 11 February 2015 Accepted 25 February 2015 Available online xxxx Keywords: MODIS Lake Taihu Total suspended matter Wind-induced resuspension Shallow turbid lake We have developed and validated a robust empirical model for estimating the concentrations of total suspended matter (TSM) in Lake Taihu (China), a large turbid inland water body. This model was generated using Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua) medium-resolution (250 m) data gathered from 2003 to 2013 and in situ data collected from a number of cruise surveys. A strong significant correlate relationship be- tween the in situ TSM data and the atmospherically corrected MODIS-Aqua remote sensing reflectance at the 645 nm band (R rs (645)) was found (R 2 = 0.70, p b 0.001, n = 150). From these data, a local TSM model was de- veloped for Lake Taihu. Long-term TSM distribution maps retrieved from the MODIS-Aqua data demonstrated marked temporal and spatial variations. Temporally, significant lower TSM was found in summer and autumn than in winter and spring (p b 0.005, t-test). The significant seasonal variability could be attributed to sediment resuspension due to changes in the wind speed between different seasons. Lake Taihu also experiences large inter-annual variations that are primarily caused by changes in wind force over the region. In particular, the TSM in Lake Taihu from 2006 to 2008 was relatively lower than in other years, which could be explained by the lower mean wind speed during these years compared to the other years. Spatially, the TSM in the Open area, especially in the southern part of this region, was consistently higher than in other sub-regions of Lake Taihu. The coverage of submerged aquatic vegetation (SAV) generally characterized East Lake Taihu as a region with a relatively lower TSM. Lake topographic conditions, SAV, and runoff discharge jointly contributed to the spatial variations in TSM. © 2015 Elsevier Inc. All rights reserved. 1. Introduction Total suspended matter (TSM) primarily consists of algal and non- algal organic detritus, living non-algal organisms, degrading phyto- plankton cells, and mineral sediments (Binding, Jerome, Bukata, & Booty, 2008; Shi, Li, Li, & Lu, 2013). TSM plays a critical role in many as- pects of lake ecology such as the ecological function of the lake and its biogeochemical cycle (Doxaran et al., 2014). TSM can directly affect light attenuation and vertical distribution (Zhang, Zhang, Ma, Feng, & Le, 2007) and therefore affect phytoplankton productivity (Liu, Zhang, Yin, Wang, & Qin, 2013) and submerged aquatic vegetation (SAV) distri- bution and growth (Chen, Hu, & Muller-Karger, 2007; Miller & McKee, 2004). Moreover, TSM also affects nutrient dynamics (Zhu et al., 2013) and the transport of micropollutants, heavy metals, and other materials (Nguyen, Leermakers, Osan, Torok, & Baeyens, 2005). Therefore, acquiring accurate information regarding the TSM distribution patterns contributes greatly to the understanding of lake ecosystem dynamics and the development of effective and quantitative monitoring schemes of aquatic environments, thus improving water quality management (Zhang, Shi, Liu, Zhou, & Qin, 2014). Traditionally, TSM in lake waters has been obtained by cruise sam- ples. The use of a limited number of measurements through traditional point sampling to represent the overall temporal and spatial distribu- tion of the biological parameters has proven to be problematic in lake waters with high spatial and temporal variations in the biogeochemical environment, especially for lakes with large spatial scales. Since the launch of the Coastal Zone Color Scanner (CZCS) in 1973, satellite image data have been used by the ocean color community to acquire the distribution of TSM at large spatial scales, with better spatial distri- bution and temporal resolution than was obtained from the traditional measurements. Consequently, there is considerable interest in the use of remote sensing methods to obtain synoptic maps of TSM in lake wa- ters, which has become a popular topic in the field of limnology. Remote Sensing of Environment 164 (2015) 43–56 ⁎ Corresponding author. Tel.: +86 25 86882198; fax: +86 25 57714759. E-mail address: ylzhang@niglas.ac.cn (Y. Zhang). http://dx.doi.org/10.1016/j.rse.2015.02.029 0034-4257/© 2015 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Remote Sensing of Environment journal homepage: www.elsevier.com/locate/rse