Development and evaluation of a mosaic approach in the WRF‐Noah framework
Development and evaluation of a mosaic approach in the WRF‐Noah framework
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DOI：
10.1002/2013jd020657
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发表时间：
2013-11
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影响因子：
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通讯作者：
Dan Li;E. Bou‐Zeid;M. Barlage;Fei Chen;J. Smith
中科院分区：
文献类型：
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作者：
Dan Li;E. Bou‐Zeid;M. Barlage;Fei Chen;J. Smith
当前的天气研究与预报（WRF） - 诺亚（Noah）建模框架仅考虑每个网格单元内的主要土地覆盖类型，在此将其称为“主要”方法。为了评估土地覆盖组成中亚网格尺度变异性的影响，在耦合的WRF - 诺亚建模系统中实施了一种马赛克/拼接方法（以下称为“马赛克”方法）。在马赛克方法中，在每个网格单元内考虑一定数量（N）的瓦片，每个瓦片代表一种土地覆盖类别。对非均匀城市/郊区环境下的晴天和降雨时段进行的WRF模拟表明，这两种方法在地表能量平衡、地表温度、近地表状态、边界层发展以及降雨分布方面产生差异。通过与多种观测数据（包括地表通量测量、中分辨率成像光谱仪（MODIS）地表温度产品以及雷达降雨估计）进行对比评估表明，与主要方法相比，马赛克方法具有更好的性能。此外，采用马赛克方法的WRF模拟结果对网格的空间分辨率不太敏感：在采用主要方法的不同分辨率模拟中观察到更大的差异。还研究了增加瓦片数量（N）对WRF模拟结果的影响。当N从1（即主要方法）增加到15时，夜间地面热通量、感热通量、地表温度和2米高度气温的变化更为显著。2米比湿在白天的变化更为显著，边界层高度在早晚过渡时段的变化最为突出。
The current Weather Research and Forecasting (WRF)‐Noah modeling framework considers only the dominant land cover type within each grid cell, which here is referred to as the “dominant” approach. In order to assess the impact of subgrid‐scale variability in land cover composition, a mosaic/tiling approach (hereafter the “mosaic” approach) is implemented into the coupled WRF‐Noah modeling system. In the mosaic approach, a certain number (N) of tiles, each representing a land cover category, is considered within each grid cell. WRF simulations of a clear sky day and a rainfall period over a heterogeneous urban/suburban setting show that the two approaches generate differences in the surface energy balance, land surface temperature, near‐surface states, boundary layer growth, as well as rainfall distribution. Evaluation against a variety of observational data (including surface flux measurements, the MODIS land surface temperature product, and radar rainfall estimates) indicates that, compared to the dominant approach, the mosaic approach has a better performance. In addition, WRF‐simulated results with the mosaic approach are less sensitive to the spatial resolution of the grid: Larger differences are observed in simulations of different resolutions with the dominant approach. The effect of increasing the number of tiles (N) on the WRF‐simulated results is also examined. When N increases from 1 (i.e., the dominant approach) to 15, changes in the ground heat flux, sensible heat flux, surface temperature, and 2 m air temperature are more significant during nighttime. Changes in the 2 m specific humidity are more significant during daytime, and changes in the boundary layer height are most prominent during the morning and afternoon transitional periods.