Air-water exchange and energy flux paths in small lakes

小湖泊中的空气-水交换和能量通量路径

• 批准号: 326125489
• 负责人: Professor Dr. Andreas Lorke
• 金额: --
• 依托单位: Department of Physics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/326125489?language=en
• 关键词: Air; water; exchange; energy; flux

Wind-induced water motions are an important physical characteristics of lakes and play a vital role in their ecology and biogeochemistry. Wind stress acting at the water surface generates a turbulent mixing layer, surface waves, large-scale flow structures as well as internal waves, which can convey energy to greater depths. The surface momentum transfer and the corresponding intensity of boundary-layer turbulence also affects the exchange of heat and dissolved gases between the lake surface and the atmosphere as well as the rate of evaporation. The processes which control air-water exchange have mainly been studied in the ocean and at high wind speeds. Not much is known about the rate of momentum transfer and its interrelation to other transfer coefficients in small lakes, where the wind speed and fetch length are typically small. In this project, we compile recently conducted atmospheric eddy-covariance (EC) measurements of momentum, heat, water vapor and gas fluxes over 10 different small lakes. This unique data set will be used to analyze the dependence of the momentum transfer from wind to water on wind speed and fetch length and to derive mechanistic relationships between the different transfer coefficients. The energy flux paths within lakes will be studied by complementing ongoing atmospheric EC measurements with extensive measurements of waves, currents and turbulence in three lakes. We will analyze the partitioning of kinetic energy into different types of flows and its fate from generation to dissipation as a function of wind speed, lake size and vertical density stratification. As a result, we provide a comprehensive mechanistic understanding of energy flux paths in small lakes in relation to atmospheric forcing. The project findings will improve current capabilities for modelling and predicting lake-atmosphere interactions and will contribute to a number of up-to-date research questions in biogeochemistry and freshwater ecology.

风引起的水运动是湖泊的重要物理特征，在其生态学和生物地球化学中起着至关重要的作用。作用在水面上的风应力会产生湍流的混合层，表面波，大规模流量结构以及内波，可以将能量传达到更大的深度。表面动量转移和相应的边界湍流强度也会影响湖面和大气之间的热量和溶解气体的交换以及蒸发速率。控制空气水交换的过程主要是在海洋和高风速中研究的。关于动量转移速率以及与小湖中其他转移系数的相互关系，在风速和提取长度通常很小。在这个项目中，我们对最近的10个不同小湖泊的动量，热量，水蒸气和气体通量进行了大气涡流（EC）测量。此独特的数据集将用于分析从风速到水的动量转移在风速和提取长度上的依赖性，并得出不同转移系数之间的机械关系。通过对三个湖泊中的波，电流和湍流的广泛测量，将研究湖泊内的能量通量路径。我们将分析动能分解为不同类型的流量及其从产生到耗散的命运，这是风速，湖泊大小和垂直密度分层的函数。结果，我们对与大气强迫有关的小湖中的能量通量路径提供了全面的机械理解。该项目的发现将提高当前的建模和预测湖泊 - 大气相互作用的能力，并将为生物地球化学和淡水生态学方面的许多最新研究问题做出贡献。

项目成果

Variable Physical Drivers of Near‐Surface Turbulence in a Regulated River

• DOI: 10.1029/2020wr027939
• 发表时间: 2021-11
• 期刊: Water Resources Research
• 影响因子: 5.4
• 作者: S. Guseva;M. Aurela;A. Cortés;R. Kivi;E. Lotsari;S. Macintyre;I. Mammarella;A. Ojala;V. Stepanenko

Energy Flux Paths in Lakes and Reservoirs

湖泊和水库中的能量通量路径

• DOI: 10.3390/w13223270
• 发表时间: 2021
• 期刊: Water
• 影响因子: 3.4
• 作者: Guseva;Casper
• 通讯作者: Casper