On the Hyperbolicity of the Bulk Air–Sea Heat Flux Functions: Insights into the Efficiency of Air–Sea Moisture Disequilibrium for Tropical Cyclone Intensification
On the Hyperbolicity of the Bulk Air–Sea Heat Flux Functions: Insights into the Efficiency of Air–Sea Moisture Disequilibrium for Tropical Cyclone Intensification
复制标题
关于大量空气-海洋热通量函数的双曲性：深入了解空气-海洋湿度不平衡对热带气旋增强的效率
DOI：
10.1175/mwr-d-20-0324.1
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发表时间：
2021
影响因子：
3.2
通讯作者：
Rudzin, Johna E.
中科院分区：
文献类型：
--
作者：
Jaimes de la Cruz, Benjamin;Shay, Lynn K.;Wadler, Joshua B.;Rudzin, Johna E.
海气热通量是热带气旋发展和维持的能量来源。在整体空气动力学公式中，这些通量是地面风速U10和海-气温度和湿度不平衡（分别为Δ T和Δq）的函数。尽管许多研究已经通过U10增加和海-气热通量增加之间的相互依赖性解释了TC增强，但最近的研究发现，即使在相对低的风条件下，TC增强也可以通过深对流涡旋结构发生，该结构从海-气水汽通量获得局部浮力。本文从整体空气动力学公式的新视角出发，对风驱动（U10）和热驱动（Δ T和Δq）海洋热吸收的相对贡献进行了评估。本文报道了这些公式以前未被注意到的显著性质：1）这些函数是双曲线的; 2）增加Δ q是提高通量的有效机制。这种新的观点被用来调查表面热通量在6 TC在稳态强度（SS），缓慢加强（SI），快速加强（RI）阶段。在SS、SI和RI期间，发现了风驱动的热吸收的封顶。在中等的U10值下，通过Δq> 5 g kg− 1的较大值进行补偿，导致RI期间强烈的内核水分通量大于600 W m− 2。Δ q的峰值优先出现在具有较高海表温度（SST）和上层海洋热含量的海洋区域。因此，增加SST和Δ q是增加表面热通量的一种非常有效的方法-这可以很容易地在TC移动到更深的温暖海洋区域时实现。
Sea-to-air heat fluxes are the energy source for tropical cyclone (TC) development and maintenance. In the bulk aerodynamic formulas, these fluxes are a function of surface wind speedU10and air–sea temperature and moisture disequilibrium (ΔTand Δq, respectively). Although many studies have explained TC intensification through the mutual dependence between increasingU10and increasing sea-to-air heat fluxes, recent studies have found that TC intensification can occur through deep convective vortex structures that obtain their local buoyancy from sea-to-air moisture fluxes, even under conditions of relatively low wind. Herein, a new perspective on the bulk aerodynamic formulas is introduced to evaluate the relative contribution of wind-driven (U10) and thermodynamically driven (ΔTand Δq) ocean heat uptake. Previously unnoticed salient properties of these formulas, reported here, are as follows: 1) these functions are hyperbolic and 2) increasing Δqis an efficient mechanism for enhancing the fluxes. This new perspective was used to investigate surface heat fluxes in six TCs during phases of steady-state intensity (SS), slow intensification (SI), and rapid intensification (RI). A capping of wind-driven heat uptake was found during periods of SS, SI, and RI. Compensation by larger values of Δq> 5 g kg−1at moderate values ofU10led to intense inner-core moisture fluxes of greater than 600 W m−2during RI. Peak values in Δqpreferentially occurred over oceanic regimes with higher sea surface temperature (SST) and upper-ocean heat content. Thus, increasing SST and Δqis a very effective way to increase surface heat fluxes—this can easily be achieved as a TC moves over deeper warm oceanic regimes.