Developing the Coupled CWRF‐FVCOM Modeling System to Understand and Predict Atmosphere‐Watershed Interactions Over the Great Lakes Region
Developing the Coupled CWRF‐FVCOM Modeling System to Understand and Predict Atmosphere‐Watershed Interactions Over the Great Lakes Region
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DOI：
10.1029/2020ms002319
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发表时间：
2020-11
影响因子：
6.8
通讯作者：
Lei Sun;Xin‐Zhong Liang;Meng Xia
中科院分区：
文献类型：
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作者：
Lei Sun;Xin‐Zhong Liang;Meng Xia
将三维水动力学与气候模型相结合对于解决多尺度相互作用是必要的，但也是困难的，而且由于在处理流域净补给量(NBS)组成部分和连接渠道流方面的问题，在预测五大湖水位波动方面很少实施。将区域气候-天气研究与预报模式(CWRF)与三维非结构网格有限体积沿海海洋模式(FVCOM)相结合，开发了一个交互式的五大湖区湖泊-大气-水文模式系统。利用一维湖、冰、雪和沉积物模拟器(LISSS)对耦合系统相对于CWRF基线的敏感性进行了评估，以代表1999-2015年间的湖泊气候条件。与CWRF相结合，FVCOM在模拟五个湖泊季节到年际尺度的水面温度、冰盖和垂直热结构方面优于LISSS，并真实地再现了区域环流格局。在温暖的季节，改善的湖况显著修正了LISSS对地表气温的高估以及更大范围的环流变化。因此，每个湖盆的降水量普遍减少，这主要是因为随着大气稳定性的增强，地表水分和热通量减少。通过动态耦合，FVCOM根据水位-落差-流量公式，直接响应CWRF NBS组件和连接渠道的水流预测水位波动。这种耦合的CWRF-FVCOM合理地捕捉到了NBS的变化，并预测了苏必利尔湖和密歇根-休伦湖的水位波动。它代表着在相互作用的区域气候和分水岭进程动态预测五大湖水位季节-年际变化方面的重大进展。
Coupling 3‐D hydrodynamics with climate models is necessary but difficult for resolving multiscale interactions and has been rarely implemented in predicting Great Lakes' water level fluctuations because of issues in treating net basin supply (NBS) components and connecting channel flows. This study developed an interactive lake‐atmosphere‐hydrology modeling system by coupling the regional Climate‐Weather Research and Forecasting model (CWRF) with the 3‐D unstructured‐grid Finite Volume Coastal Ocean Model (FVCOM) in the Great Lakes region. The sensitivity of the coupled system, relative to the CWRF baseline using the 1‐D Lake, Ice, Snow and Sediment Simulator (LISSS), was evaluated in representing lake‐climate conditions during 1999–2015 against observations. As coupled with CWRF, FVCOM outperformed LISSS in simulating water surface temperature, ice cover, and vertical thermal structure at seasonal to interannual scales for all the five lakes and realistically reproduced the regional circulation patterns. In warm seasons, the improved lake conditions significantly corrected LISSS overestimates of surface air temperature together with larger‐scale circulation changes. Consequently, precipitation was generally reduced over each lake basin, mainly because of decreased surface moisture and heat fluxes along with enhanced atmospheric stability. Through the dynamic coupling, FVCOM predicts the water level fluctuations in direct response to the CWRF NBS components and connecting channel flows based on a stage‐fall‐discharge formulation. This coupled CWRF‐FVCOM reasonably captured the NBS variations and predicted the water level fluctuations for Lakes Superior and Michigan‐Huron. It represents a major advance in interacting regional climate and watershed processes to dynamically predict Great Lakes' water level seasonal‐interannual variations.