Large-Eddy Atmosphere–Land-Surface Modelling over Heterogeneous Surfaces: Model Development and Comparison with Measurements
Large-Eddy Atmosphere–Land-Surface Modelling over Heterogeneous Surfaces: Model Development and Comparison with Measurements
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DOI：
10.1007/s10546-013-9823-0
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发表时间：
2013-04
影响因子：
4.3
通讯作者：
Y. Shao;Shaofeng Liu;J. Schween;S. Crewell
中科院分区：
文献类型：
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作者：
Y. Shao;Shaofeng Liu;J. Schween;S. Crewell
发展了一个非均匀大气和陆面过程的大涡模拟模式。这耦合LES模式与陆面方案。对陆面方案进行了新的发展，以确保在大涡尺度上充分代表大气-陆面传输。这些措施包括：（1）多层冠层方案;（2）与大涡次网格闭合一致的通量估算方法;（3）适当的土壤层配置。然后，该模型被应用到一个异质区域与60米的水平分辨率和结果进行了比较，地面和机载测量。模拟的感热通量和潜热通量与涡动相关测量结果吻合得很好。在模拟和观测的净辐射，地面热通量，土壤温度和湿度也发现了良好的协议。根据模式的结果，我们研究了感热通量和潜热通量的模式，这种模式是如何形成的，以及大涡旋如何传播和破坏陆面信号在大气中。在近地表，通量和土地利用模式被发现是密切相关的。在低边界层中，携带陆面信号的小涡旋组织并发展成较大的涡旋，将信号带到相当高的水平。因此，瞬时通量模式似乎是无关的土地利用模式，但平均而言，它们之间的相关性是显着的，并持续到约650米。对于一个给定的陆面类型，通量的散射达几百W，这是由于（1）大涡随机性;（2）快速的大涡和地面反馈;（3）与地面不均匀性有关的局部平流。
A model is developed for the large-eddy simulation (LES) of heterogeneous atmosphere and land-surface processes. This couples a LES model with a land-surface scheme. New developments are made to the land-surface scheme to ensure the adequate representation of atmosphere–land-surface transfers on the large-eddy scale. These include, (1) a multi-layer canopy scheme; (2) a method for flux estimates consistent with the large-eddy subgrid closure; and (3) an appropriate soil-layer configuration. The model is then applied to a heterogeneous region with 60-m horizontal resolution and the results are compared with ground-based and airborne measurements. The simulated sensible and latent heat fluxes are found to agree well with the eddy-correlation measurements. Good agreement is also found in the modelled and observed net radiation, ground heat flux, soil temperature and moisture. Based on the model results, we study the patterns of the sensible and latent heat fluxes, how such patterns come into existence, and how large eddies propagate and destroy land-surface signals in the atmosphere. Near the surface, the flux and land-use patterns are found to be closely correlated. In the lower boundary layer, small eddies bearing land-surface signals organize and develop into larger eddies, which carry the signals to considerably higher levels. As a result, the instantaneous flux patterns appear to be unrelated to the land-use patterns, but on average, the correlation between them is significant and persistent up to about 650 m. For a given land-surface type, the scatter of the fluxes amounts to several hundred W, due to (1) large-eddy randomness; (2) rapid large-eddy and surface feedback; and (3) local advection related to surface heterogeneity.