Abstract In this study the influence of land surface physics on the simulation of Planetary Boundary Layer (PBL) characteristics in the Advanced Research Weather Research and Forecast (WRF-ARW) is examined at the tropical costal station Kalpakkam. High resolution simulations were conducted using WRF-ARW with two land surface models (LSM) (Noah and Noah MP) for winter (2–5 February 2011) and South West (SW) monsoon (15–18 September 2010). Data from a Lower Atmospheric Wind Profiler (LAWP), GPS-Sonde, meteorological towers and sonic anemometer were used to analyze the PBL properties. Significant variation in the surface and PBL properties were noticed in the simulations with the two LSMs and various features of the PBL were produced better by Noah MP than Noah. The Noah because of higher exchange coefficients simulated more warm and humid boundary layers compared to the Noah MP. In the study region higher (lower) sensible heat flux is simulated compared to the latent and soil heat fluxes during the dry winter (rainy SW monsoon). The variation in the surface energy partitioning resulted in a variation in the simulated PBL depth by the two LSMs. The PBL simulated by Noah MP was shallower than the Noah. During winter higher Bowen ratio associated with the Noah MP resulted in stronger entrainment of upper dry air which suppressed the vertical growth of the PBL. Whereas in SW monsoon, the convective and mechanical turbulence simulated by Noah MP was less than that of Noah, which has lead to a shallow PBL in Noah MP. Overall, the Noah MP simulated the thermodynamical structure, winds and vertical extent of the PBL better than Noah. The improvement in simulations with Noah MP are due to the explicit treatment of plant canopy, snow and ground surface, tiling scheme for vegetation and bare soil, and due to moderate exchange coefficients for soil heat and moisture.

中文翻译：

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地表物理对热带海岸站边界层特性模拟的影响

摘要 在这项研究中，在热带沿海站 Kalpakkam 研究了陆地表面物理对高级研究天气研究和预报 (WRF-ARW) 中行星边界层 (PBL) 特征模拟的影响。对于冬季（2011 年 2 月 2 日至 5 日）和西南季风（2010 年 9 月 15 日至 18 日），使用 WRF-ARW 和两个地表模型 (LSM)（Noah 和 Noah MP）进行了高分辨率模拟。来自低层大气风廓线仪 (LAWP)、GPS-Sonde、气象塔和声波风速计的数据用于分析 PBL 特性。在使用两种 LSM 的模拟中注意到表面和 PBL 特性的显着变化，并且 Noah MP 比 Noah 更好地产生了 PBL 的各种特征。与诺亚 MP 相比，诺亚因为更高的交换系数模拟了更多温暖和潮湿的边界层。在研究区域，模拟较高（较低）的感热通量与干燥冬季（多雨的西南季风）的潜热和土壤热通量相比。表面能分配的变化导致两个 LSM 模拟 PBL 深度的变化。Noah MP 模拟的 PBL 比 Noah 浅。在冬季，与诺亚 MP 相关的较高鲍温比导致上层干燥空气的夹带更强，从而抑制了 PBL 的垂直增长。而在西南季风中，Noah MP 模拟的对流和机械湍流小于 Noah，这导致 Noah MP 的 PBL 较浅。总的来说，Noah MP 模拟了热力学结构，PBL的风向和垂直范围比诺亚好。使用 Noah MP 模拟的改进是由于对植物冠层、雪和地表的显式处理，植被和裸土的平铺方案，以及土壤热量和水分的适度交换系数。