Observational Estimates of Turbulence Parameters in the Atmospheric Surface Layer of Landfalling Tropical Cyclones
Observational Estimates of Turbulence Parameters in the Atmospheric Surface Layer of Landfalling Tropical Cyclones
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DOI：
10.1029/2022jd037768
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发表时间：
2023-08
期刊：
影响因子：
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通讯作者：
J. Ming;Jun A. Zhang;Xin Li;Z. Pu;M. Momen
中科院分区：
文献类型：
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作者：
J. Ming;Jun A. Zhang;Xin Li;Z. Pu;M. Momen
本研究分析了两个登陆热带气旋（TCs）的多层塔观测资料，估算了其大气表层湍流参数。动量通量、湍流动能（TKE）和耗散率随风速增大而增大，与地表类型无关。然而，在一定风速范围内，陆地上的动量通量和TKE要比沿海海洋大得多。垂直涡旋扩散系数是直接用动量通量和应变率来估计的，在粗糙的表面上，动量通量和应变率随风速的增加更快。直接通量法与摩擦速度和摩擦高度法计算的涡动扩散系数比较，结果吻合较好。另一方面，与直接通量法相比，传统的TKE方法高估了涡流扩散系数。在直接通量法的基础上，推导了两种不同表面类型的TKE方法中的标度系数，以更好地匹配垂直涡旋扩散系数。对气象模拟中TC登陆预报的垂直扩散参数化改进提供了一些指导。
This study analyzes observations collected by multilevel towers to estimate turbulence parameters in the atmospheric surface layer of two landfalling tropical cyclones (TCs). The momentum flux, turbulent kinetic energy (TKE) and dissipation rate increase with the wind speed independent of surface types. However, the momentum flux and TKE are much larger over land than over the coastal ocean at a given wind speed range. The vertical eddy diffusivity is directly estimated using the momentum flux and strain rate, which more quickly increases with the wind speed over a rougher surface. Comparisons of the eddy diffusivity estimated using the direct flux method and that using the friction velocity and height show good agreement. On the other hand, the traditional TKE method overestimates the eddy diffusivity compared to the direct flux method. The scaling coefficients in the TKE method are derived for the two different surface types to better match with the vertical eddy diffusivity based on the direct flux method. Some guidance to improve vertical diffusion parameterizations for TC landfall forecasts in weather simulations are also provided.