LakeMIP Kivu: evaluating the representation of a large, deep tropical lake by a set of one-dimensional lake models
LakeMIP Kivu: evaluating the representation of a large, deep tropical lake by a set of one-dimensional lake models
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DOI：
10.3402/tellusa.v66.21390
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发表时间：
2013-04
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影响因子：
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通讯作者：
W. Thiery;V. Stepanenko;X. Fang;K. Jöhnk;Zhongshu Li;A. Martynov;M. Perroud;Z. Subin;F. Darchambe
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文献类型：
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作者：
W. Thiery;V. Stepanenko;X. Fang;K. Jöhnk;Zhongshu Li;A. Martynov;M. Perroud;Z. Subin;F. Darchambe
非洲五大湖对当地经济(渔业)极其重要，对当地人民的生存也至关重要。在过去的几十年里，这些湖泊经历了生态系统结构和功能的快速变化，其未来的演变是一个主要问题。在这项研究中，首次对东非基伍湖(2.28°S；28.98°E)的一维湖泊模型进行了评估。在热带高海拔气候中，由于盐度和地下泉水的重要性，这个亚相湖泊的独特湖相对参与湖泊模型对比项目(LakeMIP)的七个模型提出了有价值的挑战。两个自动气象站的气象观测被用来驱动模型，而一个独特的数据集，包含自2002年以来记录的150多个温度剖面，被用来评估模型的性能。模拟只在淡水层(60米)和平均湖深(240米)上进行，因为基伍湖的盐度在60米以下随着深度的增加而增加，而且一些湖泊模型没有考虑盐度对湖泊分层的影响。所有模型都能够再现基伍湖的混合季节性，以及湖热变化的幅度和季节周期。模型之间的差异可以归因于对辐射强迫的处理和湍流热通量计算的不同。风速和太阳辐射的波动解释了观测到的水柱温度的年际变化。深部模拟和观测到的高温层结之间的良好一致性也表明，模型的一个子集能够解释盐度和地热对深水层结的影响。最后，基于这项研究中识别出的优势和劣势，有可能为特定的研究目的选择一维湖泊模型。
The African great lakes are of utmost importance for the local economy (fishing), as well as being essential to the survival of the local people. During the past decades, these lakes experienced fast changes in ecosystem structure and functioning, and their future evolution is a major concern. In this study, for the first time a set of one-dimensional lake models are evaluated for Lake Kivu (2.28°S; 28.98°E), East Africa. The unique limnology of this meromictic lake, with the importance of salinity and subsurface springs in a tropical high-altitude climate, presents a worthy challenge to the seven models involved in the Lake Model Intercomparison Project (LakeMIP). Meteorological observations from two automatic weather stations are used to drive the models, whereas a unique dataset, containing over 150 temperature profiles recorded since 2002, is used to assess the model's performance. Simulations are performed over the freshwater layer only (60 m) and over the average lake depth (240 m), since salinity increases with depth below 60 m in Lake Kivu and some lake models do not account for the influence of salinity upon lake stratification. All models are able to reproduce the mixing seasonality in Lake Kivu, as well as the magnitude and seasonal cycle of the lake enthalpy change. Differences between the models can be ascribed to variations in the treatment of the radiative forcing and the computation of the turbulent heat fluxes. Fluctuations in wind velocity and solar radiation explain inter-annual variability of observed water column temperatures. The good agreement between the deep simulations and the observed meromictic stratification also shows that a subset of models is able to account for the salinity- and geothermal-induced effects upon deep-water stratification. Finally, based on the strengths and weaknesses discerned in this study, an informed choice of a one-dimensional lake model for a given research purpose becomes possible.