Remote estimates of CDOM using Sentinel-2 remote sensing data in reservoirs with different trophic states across China

Yingxin Shang; Ge Liu; Zhidan Wen; Pierre-Andre Jacinthe; Kaishan Song; Bai Zhang; Lili Lyu; Sijia Li; Xiang Wang; Xiangfei Yu

doi:10.1016/j.jenvman.2021.112275

Remote estimates of CDOM using Sentinel-2 remote sensing data in reservoirs with different trophic states across China

J Environ Manage. 2021 May 15:286:112275. doi: 10.1016/j.jenvman.2021.112275. Epub 2021 Mar 5.

Authors

Yingxin Shang¹, Ge Liu², Zhidan Wen³, Pierre-Andre Jacinthe⁴, Kaishan Song⁵, Bai Zhang¹, Lili Lyu¹, Sijia Li¹, Xiang Wang¹, Xiangfei Yu⁶

Affiliations

¹ Northeast Institute of Geography and Agroecology, CAS, Changchun, 130102, China.
² Northeast Institute of Geography and Agroecology, CAS, Changchun, 130102, China; Jingyuetan Remote Sensing Observation Station, CAS, Changchun, 130102, China. Electronic address: liugers@163.com.
³ Northeast Institute of Geography and Agroecology, CAS, Changchun, 130102, China; Jingyuetan Remote Sensing Observation Station, CAS, Changchun, 130102, China.
⁴ Department of Earth Sciences, Indiana University-Purdue University Indianapolis, IN, USA.
⁵ Northeast Institute of Geography and Agroecology, CAS, Changchun, 130102, China; Jingyuetan Remote Sensing Observation Station, CAS, Changchun, 130102, China; School of Environment and Planning, Liaocheng University, Liaocheng, 252000, China.
⁶ Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, 130118, China.

PMID: 33684799
DOI: 10.1016/j.jenvman.2021.112275

Abstract

Chromophoric dissolved organic matter (DOM) is called as CDOM which could affect the optical properties of surface waters, and is a useful parameter for monitoring complex inland aquatic systems. Large-scale monitoring of CDOM using remote-sensing has been a challenge due to the poor transferability of CDOM retrieval models across regions. To overcome these difficulties, a study is conducted using Sentinel-2 images, in situ reflectance spectral data, and water chemical parameters at 93 water reservoirs across China classified by trophic state. Empirical algorithms are established between CDOM absorption coefficient a_CDOM(355) and reflectance band ratio (B5/B2,vegetation Red Edge/Blue) acquired in situ and via Sentinel-2 MSI sensors. Relationships are stronger (r² > 0.7, p < 0.05) when analysis is conducted separately by trophic states. Validation models show that, by accounting for trophic state of reservoirs and using B5/B2 band ratios, it is possible to expand the geographical range of remote sensing-based models to determine CDOM. However, the accuracy of model validation decreased from oligotrophic (r²: 0.86) to eutrophic reservoirs (r²: 0.82), likely due to increased complexity of CDOM sources in nutrient-rich systems. This study provides a strategy for using local and remote-sensing data to monitor the spatial variations of CDOM in reservoirs based on different trophic states, and will contribute to water resources management.

Keywords: CDOM; Reservoirs; Sentinel-2; Trophic state.

MeSH terms

China
Environmental Monitoring*
Remote Sensing Technology*