Climate- and human-induced changes in suspended particulate matter over Lake Hongze on short and long timescales

Cao, Zhigang; Duan, Hongtao; Feng, Lian; Ma, Ronghua; Xue, Kun

doi:10.1016/j.rse.2017.02.007

Cited by 152 publications

(95 citation statements)

References 44 publications

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“…Compared with other terrestrial remote sensing satellites, the spectral resolution of MODIS can meet the spectral requirements for inland water bodies with complex optical characteristics. In addition, previous studies have used MODIS series data for monitoring the water quality in Lake Hongze [1,30]. MODIS-Aqua L-0 data at 250-m resolution spanning the period between January 2003 and December 2017 were freely obtained from the NASA Ocean color Archive (http://oceandata.sci.gsfc.nasa.gov/).…”

Section: Satellite Data Acquisition and Processmentioning

confidence: 99%

“…Water transparency is mainly affected by the optical components in the water body: pure water, suspended matter, chromophoric dissolved organic matter, and phytoplankton. In order to explore the effect of suspended matter on the transparency, we adopted an empirical model developed in Lake Hongze using two bands (645 nm and 1240 nm) of MODIS to estimate the total suspended matter (TSM) concentration [30]. We applied 1785 high-quality images to the model to obtain a TSM concentration dataset from 2003 to 2017.…”

Section: Satellite Data Acquisition and Processmentioning

confidence: 99%

“…Lake Hongze is the fourth largest freshwater lake in China and provide important role in water supply, irrigation, fishery, etc. The water quality of Lake Hongze has attracted more attention due to strong human activities such as the South-to-North Water Transfer Project and dredging activities [30][31][32]. However, studies have shown a clear increase in suspended particulate concentrations in 2012 and first observed sand mining vessels using LANDSAT data and VIIRS data in Lake Hongze [30,33].…”

Section: Introductionmentioning

confidence: 99%

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Decline in Transparency of Lake Hongze from Long-Term MODIS Observations: Possible Causes and Potential Significance

Shi

Zhang

et al. 2019

Remote Sensing

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Transparency is an important indicator of water quality and the underwater light environment and is widely measured in water quality monitoring. Decreasing transparency occurs throughout the world and has become the primary water quality issue for many freshwater and coastal marine ecosystems due to eutrophication and other human activities. Lake Hongze is the fourth largest freshwater lake in China, providing water for surrounding cities and farms but experiencing significant water quality changes. However, there are very few studies about Lake Hongze's transparency due to the lack of long-term monitoring data for the lake. To understand long-term trends, possible causes and potential significance of the transparency in Lake Hongze, an empirical model for estimating transparency (using Secchi disk depth: SDD) based on the moderate resolution image spectroradiometer (MODIS) 645-nm data was validated using an in situ dataset. Model mean absolute percentage and root mean square errors for the validation dataset were 27.7% and RMSE = 0.082 m, respectively, which indicates that the model performs well for SDD estimation in Lake Hongze without any adjustment of model parameters. Subsequently, 1785 cloud-free images were selected for use by the validated model to estimate SDDs of Lake Hongze in 2003-2017. The long-term change of SDD of Lake Hongze showed a decreasing trend from 2007 to 2017, with an average of 0.49 m, ranging from 0.57 m in 2007 to 0.42 m in 2016 (a decrease of 26.3%), which indicates that Lake Hongze experienced increased turbidity in the past 11 years. The loss of aquatic vegetation in the northern bays may be mainly affected by decreases of SDD. Increasing total suspended matter (TSM) concentration resulting from sand mining activities may be responsible for the decreasing trend of SDD.

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Section: Satellite Data Acquisition and Processmentioning

confidence: 99%

Section: Satellite Data Acquisition and Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Decline in Transparency of Lake Hongze from Long-Term MODIS Observations: Possible Causes and Potential Significance

Shi

Zhang

et al. 2019

Remote Sensing

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“…MODIS is widely used satellite imagery to monitor the optical properties and water constituents in ocean coastal and inland waters [e.g., Shi and Wang, 2010;Hu et al, 2004Hu et al, , 2010Wang et al, 2009Wang et al, , 2011Wang et al, , 2012Feng et al, 2014;Chen et al, 2014;Zhang et al, 2016;Cao et al, 2017]. More satellite data should be employed to increase the temporal-spatial scale to get more detailed information of the water environment [Nobuhle et al, 2014;Huang et al, 2015b;Song et al, 2017].…”

Section: Potential Application Of the K D (490) Model To Other Sensormentioning

confidence: 99%

Wind and rainfall regulation of the diffuse attenuation coefficient in large, shallow lakes from long‐term MODIS observations using a semianalytical model

et al. 2017

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Knowledge of the variation and regulation of the diffuse attenuation coefficient is important for management of lake water quality and ecological environments. Data were collected seven times (378 samples) from 2006 to 2011 in Lake Taihu to improve the existing semianalytical model of diffuse attenuation coefficient at 490 nm (Kd(490)) by measuring in situ Kd(490) and remote sensing reflectance (Rrs). This semianalytical model was applied to determine the long‐term variation of Kd(490) and its driving factors from Moderate Resolution Imaging Spectroradiometer (MODIS) images. Our semianalytical model of Kd(490) improves the retrieval accuracy of Kd(490) from 29.60% to 22.58% (root‐mean‐square percentage error) and 24.28 ± 18.54% (mean value ± standard deviation) to 19.29 ± 14.34% (mean absolute relative error). The Kd(490) from maps produced from MODIS images clearly present the temporal and spatial variations of Kd(490). This indicates the suitability of using the improved semianalytical model and MODIS to observe Kd(490) in turbid shallow inland waters. Long‐term MODIS observation of Kd(490) shows distinct seasonal and spatial variations. Temporally, the highest and the lowest Kd(490) were found in winter and in summer, respectively. Spatially, high Kd(490) values were primarily distributed in the southwestern and northwestern Lake Taihu, and relatively low Kd(490) values were distributed in Meiliang Bay and Gonghu Bay (the eastern part of the lake and East Bay were excluded in this study due to invalid retrieval results of Kd(490)). Many covarying points were found between Kd(490) and maximum wind speed from long‐term observations, suggesting that wind‐induced sediment resuspension is the principal driver of high Kd(490). Correlation was also observed between Kd(490) and heavy rainfall events, suggesting the regulating effect of heavy rainfall.

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“…The SPM concentrations were gravimetrically determined from samples collected on pre-combusted and pre-weighed 47 mm Whatman GF/C glass-fiber filters that were dried at 105 • C overnight. SPM was differentiated into SPIM and SPOM by burning organic matter from the filters at 550 • C for 3 h and weighing the filters again [36][37][38]. The absorption coefficients of the total particulate matter (a p ), phytoplankton pigments (a ph ), and detritus (a d ) were determined using the quantitative filter technique [39,40] with 47 mm Whatman GF/C glass-fiber filters and a Shimadzu UV-2600 spectrophotometer.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Downwelling Diffuse Attenuation Coefficient of Lake Water with the Sentinel-3A OLCI

et al. 2017

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Abstract:The Ocean and Land Color Imager (OLCI) on the Sentinel-3A satellite, which was launched by the European Space Agency in 2016, is a new-generation water color sensor with a spatial resolution of 300 m and 21 bands in the range of 400-1020 nm. The OLCI is important to the expansion of remote sensing monitoring of inland waters using water color satellite data. In this study, we developed a dual band ratio algorithm for the downwelling diffuse attenuation coefficient at 490 nm (K d (490)) for the waters of Lake Taihu, a large shallow lake in China, based on data measured during seven surveys conducted between 2008 and 2017 in combination with Sentinel-3A-OLCI data. The results show that: (1) Compared to the available K d (490) estimation algorithms, the dual band ratio (681 nm/560 nm and 754 nm/560 nm) algorithm developed in this study had a higher estimation accuracy (N = 26, coefficient of determination (R 2 ) = 0.81, root-mean-square error (RMSE) = 0.99 m −1 and mean absolute percentage error (MAPE) = 19.55%) and validation accuracy (N = 14, R 2 = 0.83, RMSE = 1.06 m −1 and MAPE = 27.30%), making it more suitable for turbid inland waters; (2) A comparison of the OLCI K d (490) product and a similar Moderate Resolution Imaging Spectroradiometer (MODIS) product reveals a high consistency between the OLCI and MODIS products in terms of the spatial distribution of K d (490). However, the OLCI product has a smoother spatial distribution and finer textural characteristics than the MODIS product and contains notably higher-quality data; (3) The K d (490) values for Lake Taihu exhibit notable spatial and temporal variations. K d (490) is higher in seasons with relatively high wind speeds and in open waters that are prone to wind-and wave-induced sediment resuspension. Finally, the Sentinel-3A-OLCI has a higher spatial resolution and is equipped with a relatively wide dynamic range of spectral bands suitable for inland waters. The Sentinel-3B satellite will be launched soon and, together with the Sentinel-3A satellite, will form a two-satellite network with the ability to make observations twice every three days. This satellite network will have a wider range of application and play an important role in the monitoring of inland waters with complex optical properties.

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Climate- and human-induced changes in suspended particulate matter over Lake Hongze on short and long timescales

Cited by 152 publications

References 44 publications

Decline in Transparency of Lake Hongze from Long-Term MODIS Observations: Possible Causes and Potential Significance

Decline in Transparency of Lake Hongze from Long-Term MODIS Observations: Possible Causes and Potential Significance

Wind and rainfall regulation of the diffuse attenuation coefficient in large, shallow lakes from long‐term MODIS observations using a semianalytical model

Determination of the Downwelling Diffuse Attenuation Coefficient of Lake Water with the Sentinel-3A OLCI

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