THE TAIHU EDDY FLUX NETWORK: An Observational Program on Energy, Water, and Greenhouse Gas Fluxes of a Large Freshwater Lake

• Published in: Bulletin of the American Meteorological Society 2014-10, Vol.95 (10), p.1583-1594
• Main Authors: Lee, Xuhui, Liu, Shoudong, Xiao, Wei, Wang, Wei, Gao, Zhiqiu, Cao, Chang, Hu, Cheng, Hu, Zhenghua, Shen, Shuanghe, Wang, Yongwei, Wen, Xuefa, Xiao, Qitao, Xu, Jiaping, Yang, Jinbiao, Zhang, Mi
• Format: Article
• Language: English
• Subjects: Algae; Aquatic ecosystems; Atmosphere; Atmospheric circulation; Carbon; Carbon dioxide; Carbon sequestration; Covariance; Environmental aspects; Freshwater lakes; Greenhouse gases; Heat; Lake water; Lakes; Macrophytes; Meteorology; Methane; Modeling; Nitrous oxide; Outdoor air quality; Pollution load; Surface temperature; Water temperature
• ISSN: 0003-0007; 1520-0477
• DOI: 10.1175/bams-d-13-00136.1

Lakes are an important component of the climate system. They provide moisture for precipitation, buffer temperature variations, and contribute to regional atmospheric carbon budgets. This article describes an eddy covariance (EC) mesonet on Lake Taihu, a large (area 2400 km²) and shallow (depth 2 m) lake situated in the heavily populated Yangtze River Delta, China. The mesonet consists of five lake sites, representing different biological attributes and wind–wave patterns, and a land site near the lake shore. Common to all the sites are standard EC instruments for measurement of the momentum, sensible heat, water vapor, and CO₂ flux. One site is also equipped with laser-based analyzers for precise measurement of the CO₂, CH₄, and H₂O mixing ratios and their isotopic compositions. To the authors’ best knowledge, this is the first lake eddy flux mesonet. Early results reveal evidence of biological and pollution controls on the surface–air fluxes of energy, momentum, and greenhouse gases across the lake. The data will be used to address five science questions: 1) Are lake–air parameterizations established for deep lakes applicable to shallow lakes? 2) Why are lake–land breeze circulations less prevalent in the Taihu lake basin than in lake basins in northern latitudes? 3) How do algal blooms alter the lake–atmosphere interactions? 4) Is this eutrophic lake a source or sink of atmospheric CO₂? 5) Does the decay of algal and macrophyte biomass contribute significant amounts of CH4 to the atmosphere?