MERIS observations of chlorophyll-a dynamics in Erhai Lake between 2003 and 2009

• Published in: International journal of remote sensing Vol. 35; no. 24; pp. 8309 - 8322
• Main Authors: Han, Xingxing, Feng, Lian, Chen, Xiaoling, Yesou, Herve
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 17-12-2014
• Subjects: Algorithms; Animal, plant and microbial ecology; Applied geophysics; Biological and medical sciences; Dynamics; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Imaging spectrometers; Internal geophysics; Lakes; Springs; Summer; Teledetection and vegetation maps; Waste water; Yunnan China; Far East; Asia; China; China, People's Rep., Yunnan Prov; China, People's Rep., Erhai L; algorithms; models; Dynamic characteristic; time variations; software; fresh-water environment; eutrophication; Space remote sensing; concentration; clouds; variability; Chlorophyll a; Interannual variation; dynamics; imagery; spatial variations; lakes; performances; seasonal variations; methodology
• ISSN: 0143-1161; 1366-5901
• DOI: 10.1080/01431161.2014.985395

The Medium Resolution Imaging Spectrometer (MERIS) was used to investigate the spatial and temporal dynamics of chlorophyll-a (chl-a) in Erhai Lake, the second largest freshwater lake in the Yunnan province of China. Six chl-a retrieval models, including four Basic ERS & Envisat (A)ATSR and Meris Toolbox (BEAM) software-incorporated algorithms and MERIS three-band and two-band models, were validated to find the best fit to extract chl-a concentration in Erhai Lake. With a chl-a range of 5-15 mg m
-3
, the Lakes/Eutrophic method showed the best performance. The algorithm was then applied to eight-year cloud-free MERIS images between 2003 and 2009, with seasonal and inter-annual variability analysed. Long-term chl-a distributions of Erhai Lake revealed significant seasonal and inter-annual variability. The mean chl-a of the south lake was higher in summer (14.3 mg m
-3
) than in spring (10.1 mg m
-3
), while generally lower chl-a was found in the north lake with a mean chl-a of 6.4 mg m
-3
in spring and 9.0 mg m
-3
in summer, respectively. An increasing trend was found between 2006 and 2009, and the increasing rate was 12.9% for annual chl-a of the entire lake. While chl-a seasonality was attributed to the seasonal changes of the local temperature, the inter-annual variation was possibly linked to the discharged wastewater from Dali City. This work could provide critical information for decision-makers to manage Erhai Lake's aquatic ecosystems.