Lake‐Atmosphere Heat Flux Dynamics of a Thermokarst Lake in Arctic Siberia
Lake‐Atmosphere Heat Flux Dynamics of a Thermokarst Lake in Arctic Siberia
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DOI：
10.1029/2017jd027751
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发表时间：
2018-05
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影响因子：
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通讯作者：
D. Franz;I. Mammarella;J. Boike;G. Kirillin;T. Vesala;Niko Bornemann;E. Larmanou;M. Langer;T. S
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作者：
D. Franz;I. Mammarella;J. Boike;G. Kirillin;T. Vesala;Niko Bornemann;E. Larmanou;M. Langer;T. S
2014年4月至8月，我们在西伯利亚热岩溶湖进行了涡度相关测量。研究地点位于勒拿河三角洲，其特征是一个浮冰湖。热通量的大小，方向和时间模式取决于湖面条件（“冻结”冰盖，冰盖融化，和开放的水）。在冻结的冰盖条件下显着的热量释放突出了湖泊的景观热收支和水平衡的重要性。在开放水域期间，能量平衡几乎关闭，并突出了在冰盖期间融化能量对其关闭的影响。显热和潜热动力学驱动的温度和水汽梯度的风速缩放，分别。我们计算了整体空气动力学传递系数，并评估了在原位和三个独立的热通量参数化方案的性能。我们发现，散装传输模型执行中度至较差的不同湖面条件。在开放水域期间，小尺度的时间变率不能用模型来表示，特别是在潜热通量的情况下。模型结果对特定模型类型的敏感性低于对地表水温度测量精度的敏感性，这取决于经过深思熟虑的测量设计。我们的研究强调了对未来类似活动至关重要的考虑因素，以便面对北极湖泊特别是在冰盖时期遇到的测量挑战。
We conducted eddy covariance measurements from April to August 2014 on a Siberian thermokarst lake. The study site is located in the Lena River Delta and characterized as a floating ice lake. Heat fluxes differed in magnitudes, directions and temporal patterns depending on the lake surface conditions (“frozen” ice cover, ice cover melt, and open water). Significant heat release during frozen ice cover conditions highlighted the importance of lakes for the landscape heat budget and water balance. The energy balance was nearly closed during the open water period and highlighted the impact of melting energy on its closure during the ice cover period. Sensible and latent heat dynamics were driven by temperature and water vapor gradients scaled by wind speed, respectively. We calculated bulk aerodynamics transfer coefficients and evaluated the performance of the derived in situ and three independent heat flux parameterization schemes. We found that bulk transfer models perform moderately to poorly for the different lake surface conditions. During the open water period small‐scale temporal variability could not be represented by the models, particularly in case of latent heat flux. The model results were less sensitive to the specific model type than to the accuracy of the surface water temperature measurement, which is dependent on a well‐thought‐out measurement design. Our study stresses considerations that are crucial for similar campaigns in the future, in order to face the measurement challenges encountered on arctic lakes especially during the ice cover period.