Predicting thermal responses of an Arctic lake to whole-lake warming manipulation at Toolik Field Station July 1, 2018 to August 31, 2018

We investigated how lake thermal processes responded to whole-lake warming manipulation for in an Arctic Alaskan lake through observations and numerical modeling. The warming manipulation was conducted by artificially heating the epilimnion of the lake as a proxy for climate warming. We performed numerical modeling and used an improved lake scheme based on the Community Land Model (CLM). We simulated a control run (CTL) without warming and a warming manipulation simulation (WARM). Results indicated that the WARM simulation accurately captured the observed lake temperature profiles where water stratification was extended in time, and water stability was strengthened. Two additional sensitivity tests with different warming onset dates and of the same warming durations showed that earlier onsets of warming are predicted to make the lake water column more stable and less easily mixed relative to a later onset of warming. The results of this study provide a more complete understanding of lake thermal processes in Arctic freshwater lake systems and of how they will respond to predicteda future warming world.本研究通过野外观测与数值模拟手段，探究了阿拉斯加北极地区某湖泊的全湖增温操控实验对湖泊热动力过程的影响。该增温操控实验通过人工加热湖泊的表水层（epilimnion）以模拟气候增温效应；研究中采用了基于公用陆面模式（Community Land Model, CLM）改进的湖泊参数化方案，设置了无增温的对照试验（CTL）与增温操控模拟试验（WARM）两组方案开展数值模拟。结果表明，WARM试验准确复现了观测到的湖泊水温剖面特征，水体层结持续时间得以延长，水体稳定性显著增强。此外，两组采用相同增温时长、不同增温起始日期的敏感性试验结果显示，相较于较晚启动的增温处理，更早开始的增温会使湖泊水体层更加稳定，更难发生混合。本研究结果有助于更全面地理解北极淡水湖泊系统的热动力过程，以及其在未来预估的增温气候背景下的响应机制。