The Role of Vertical Diffusion Parameterizations in the Dynamics and Accuracy of Simulated Intensifying Hurricanes
The Role of Vertical Diffusion Parameterizations in the Dynamics and Accuracy of Simulated Intensifying Hurricanes
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DOI：
10.1007/s10546-023-00818-w
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发表时间：
2023-07
影响因子：
4.3
通讯作者：
L. Matak;M. Momen
中科院分区：
文献类型：
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作者：
L. Matak;M. Momen
飓风流中的旋转可以显著影响湍流边界层的动力学和结构。尽管飓风边界层具有这种独特的特征，但目前天气模式中的行星边界层（PBL）方案既没有专门设计，也没有全面测试飓风流动。本文的目的是弥合这方面的知识差距的垂直扩散深度和规模的作用，模拟飓风强度，大小和轨道的特点。为此，使用天气研究与预报（WRF）模式中两种广泛使用的本地和非本地PBL方案，模拟了5个经历一个加强期的大型飓风个例。总之，80 WRF模拟进行了不同的网格分辨率，边界层方案，涡动扩散的深度和幅度，和边界层的高度。通过降低现有的垂直扩散深度和强度，与默认模式相比，飓风强度预测平均提高了约38%和约24%。因此，结果表明，目前的PBL计划在WRF是过度扩散的模拟主要飓风，因为他们没有考虑到湍流的抑制作用，在旋转的飓风流。本文对垂直扩散在模拟飓风动力学中的作用产生了新的见解，并为提高NWP的PBL方案以改进飓风预报提供了一些指导。
Rotation in hurricane flows can significantly impact the dynamics and structure of the turbulent boundary layer. Despite this unique feature of hurricane boundary layers, the current planetary boundary layer (PBL) schemes in weather models are neither specifically designed nor comprehensively tested for intensifying hurricane flows. The objective of this paper is to bridge this knowledge gap by characterizing the role of vertical diffusion depth and magnitude in simulated hurricane intensity, size, and track. To this end, five major hurricane cases undergoing an intensification period are simulated using two widely used local and non-local PBL schemes in Weather Research and Forecasting (WRF) model. In total, eighty WRF simulations are conducted by varying the grid resolution, PBL scheme, eddy diffusivity depth and magnitude, and PBL height. By decreasing the existing vertical diffusion depth and magnitude, on average, ~ 38 and ~ 24% improvements in hurricane intensity forecasts were obtained compared to the default models. Hence, the results indicate that the current PBL schemes in WRF are overly diffusive for simulating major hurricanes since they do not account for turbulence suppression effects in rotating hurricane flows. The paper yields new insights into the role of vertical diffusion in simulated hurricane dynamics and provides some guidance to enhance the PBL schemes of NWPs for improved hurricane forecasts.