Purdue University, Department of Earth, Atmospheric, and Planetary Sciences, 550 Stadium Mall Drive HAMP 3221, West Lafayette, IN, 47907, USA.
School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794, USA.
Nat Commun. 2017 Nov 8;8(1):1360. doi: 10.1038/s41467-017-01546-9.
The relationship between the two common measures of tropical cyclone intensity, the central pressure deficit and the peak near-surface wind speed, is a long-standing problem in tropical meteorology that has been approximated empirically yet lacks physical understanding. Here we provide theoretical grounding for this relationship. We first demonstrate that the central pressure deficit is highly predictable from the low-level wind field via gradient wind balance. We then show that this relationship reduces to a dependence on two velocity scales: the maximum azimuthal-mean azimuthal wind speed and half the product of the Coriolis parameter and outer storm size. This simple theory is found to hold across a hierarchy of models spanning reduced-complexity and Earth-like global simulations and observations. Thus, the central pressure deficit is an intensity measure that combines maximum wind speed, storm size, and background rotation rate. This work has significant implications for both fundamental understanding and risk analysis, including why the central pressure better explains historical economic damages than does maximum wind speed.
这两种常见的热带气旋强度度量指标（中心气压亏缺和近地表峰值风速）之间的关系，是热带气象学中长期存在的问题，尽管已有经验近似，但缺乏物理理解。本文为该关系提供了理论依据。我们首先证明，通过梯度风平衡，中心气压亏缺可从低空风场高度预测。然后，我们表明这种关系简化为对两个速度尺度的依赖：最大的平均角风速和科里奥利参数与风暴外部尺寸乘积的一半。这一简单理论适用于跨越简化模型和地球般的全球模拟和观测的层次结构。因此，中心气压亏缺是一种综合了最大风速、风暴尺寸和背景旋转率的强度度量指标。这项工作对基础理解和风险分析都具有重要意义，包括为什么中心气压比最大风速更好地解释了历史经济损失。
