Spatiotemporal Variation in Particulate Organic Carbon Based on Long-Term MODIS Observations in Taihu Lake, China

Abstract

Abstract:In situ measured values of particulate organic carbon (POC) in Taihu Lake and remote sensing reflectance observed by three satellite courses from 2014 to 2015 were used to develop an near infrared-red (NIR-Red) empirical algorithm of POC for the Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua) satellite image. The performance of the POC algorithm is highly consistent with the in situ measured POC, with root mean square error percentage (RMSPs) of 38.9% and 31.5% for two independent validations, respectively. The MODIS-derived POC also shows an acceptable result, with RMSPs of 53.6% and 61.0% for two periods of match-up data. POC from 2005 to 2007 is much higher than it is from 2002 to 2004 and 2008 to 2013, due to a large area of algal bloom. Riverine flux is an important source of POC in Taihu Lake, especially in the lake's bank and bays. The influence of a terrigenous source of POC can reach the center lake during periods of heavy precipitation. Sediment resuspension is also a source of POC in the lake due to the area's high dynamic ratio (25.4) and wind speed. The source of POC in an inland shallow lake is particularly complex, and additional research on POC is needed to more clearly reveal its variation in inland water.

Mountain lakes: Eyes on global environmental change

“…Advances in high-frequency sensors that allow for continuous, high-resolution measurements of physical variables, including temperature, chlorophyll a and dissolved oxygen (e.g., Jacquet et al, 2014) and monitoring using remote sensing (Riffler et al, 2015, Huang et al, 2017, hold potential for water monitoring in remote regions where access can be challenging. In their bibliometric analysis, Zhang et al 2017suggest that remote sensing research should focus on water quality monitoring, phenology, and climate change impacts, but complications like cloud cover, edge effects, adjacency effect, and turbidity have limited research to relatively large lakes.…”

Automatic Extraction of Open Water Using Imagery of Landsat Series

“…Taihu Lake, the third largest freshwater lake in China (area ~ 2428 km 2 including islands or 2338 km 2 without islands), is a typical shallow inland lake with average depth of 1.9 m (maximum depth is about 2.6 m) [37][38][39][40]. It is located in the downstream of Yangtze River (Figure 1), on the southern Yangtze River Delta [41,42]. Taihu Lake falls in the East Asia Monsoon climate region with annual mean temperature of 14.0-16.2 °C and mean annual precipitation of 1000-1400 mm [43][44][45].…”

Automatic Detection of Algal Blooms Using Sentinel-2 MSI and Landsat OLI Images

“…It is a drinking water source for more than 40 million people and plays an important role in aquaculture, tourism and flood control [8,58,59]. However, the large population, urbanization, industrial development, intensive agriculture and tourism activities caused hypereutrophic and experienced algal blooms in Lake Taihu since 1990s [61][62][63]. During the past 20 years, more than 25% area of the whole lake has been frequently covered by floating algae in spring and summer due to eutrophication [62][63][64][65].…”

“…However, the large population, urbanization, industrial development, intensive agriculture and tourism activities caused hypereutrophic and experienced algal blooms in Lake Taihu since 1990s [61][62][63]. During the past 20 years, more than 25% area of the whole lake has been frequently covered by floating algae in spring and summer due to eutrophication [62][63][64][65]. A very severe cyanobacterial bloom occurred in May 2007, depriving more than 2 million people from drinking water for 8 days (May 30 th to June 6 th ) [60].…”