Lake topography and wind waves determining seasonal-spatial dynamics of total suspended matter in turbid Lake Taihu, China: assessment using long-term high-resolution MERIS data

Yunlin Zhang; Kun Shi; Xiaohan Liu; Yongqiang Zhou; Boqiang Qin

doi:10.1371/journal.pone.0098055

Lake topography and wind waves determining seasonal-spatial dynamics of total suspended matter in turbid Lake Taihu, China: assessment using long-term high-resolution MERIS data

PLoS One. 2014 May 20;9(5):e98055. doi: 10.1371/journal.pone.0098055. eCollection 2014.

Authors

Yunlin Zhang¹, Kun Shi¹, Xiaohan Liu², Yongqiang Zhou², Boqiang Qin¹

Affiliations

¹ Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
² Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China; University of Chinese Academy of Sciences, Beijing, China.

Abstract

Multiple comprehensive in situ bio-optical investigations were conducted from 2005 to 2010 and covered a large variability of total suspended matter (TSM) in Lake Taihu to calibrate and validate a TSM concentration estimation model based on Medium Resolution Imaging Spectrometer (MERIS) data. The estimation model of the TSM concentration in Lake Taihu was developed using top-of-atmosphere (TOA) radiance of MERIS image data at band 9 in combination with a regional empirical atmospheric correction model, which was strongly correlated with the in situ TSM concentration (r(2) = 0.720, p<0.001, and n = 73). The relative root mean square error (RRMSE) and mean relative error (MRE) were 36.9% and 31.6%, respectively, based on an independent validation dataset that produced reliable estimations of the TSM concentration. The developed algorithm was applied to 50 MERIS images from 2003 to 2011 to obtain a high spatial and temporal heterogeneity of TSM concentrations in Lake Taihu. Seasonally, the highest and lowest TSM concentrations were found in spring and autumn, respectively. Spatially, TSM concentrations were high in the southern part and center of the lake and low in Xukou Bay, East Lake Taihu. The lake topography, including the water depth and distance from the shore, had a significant effect on the TSM spatial distribution. A significant correlation was found between the daily average wind speed and TSM concentration (r(2)= 0.685, p<0.001, and n = 50), suggesting a critical role of wind speed in the TSM variations in Lake Taihu. In addition, a low TSM concentration was linked to the appearance of submerged aquatic vegetation (SAV). Therefore, TSM dynamics were controlled by the lake topography, wind-driven sediment resuspension and SAV distribution.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Atmosphere / analysis
China
Environmental Monitoring*
Geography
Lakes*
Models, Theoretical*
Satellite Imagery
Seasons*
Spatial Analysis*
Wind*

Grants and funding

This study was jointly funded by the National Natural Science Foundation of China (grants 41325001, 41230744, 41271355), the Key Program of Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences (NIGLAS2012135003), the Major Projects on Control and Rectification of Water Body Pollution (2012ZX07101-010), and the Provincial Natural Science Foundation of Jiangsu of China (BK2012050). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.