The role of convective available potential energy for tropical cyclone intensification

所要求的研究项目将侧重于热带气旋发展的动态。将进行数值模式模拟和分析，以揭示CAPE是否存在于强化阶段，它是如何分布的，以及它可能对演变动力学发挥的特殊作用。根据WISHE（Wind Induced Surface Heat Exchange）理论，CAPE的存在并不是增强过程的必要条件。然而，如果热带气旋外围区域的净潜热加热由于低相对湿度的假设而消失，则该理论只能得出结论性的结果。当CAPE可以存储在流入边界层中时，这种假设是不必要的。轴对称云解析模式HURMOD和三维云模式CM1将用于研究。这项研究是基于这样的假设，即CAPE有助于提高集约化率。这一假设可以通过一个简单的对流参数化方案来验证，在该方案中，CAPE被减少到一个指定的时间尺度。当强化也发生在任意小的弛豫时间尺度上时，这表明WISHE是相关的。将开发一个概念模型，使CAPE对集约化的影响更容易理解。

The requested research project will focus on the dynamics of tropical cyclone development. Numerical model simulations will be conducted and analysed to reveal whether CAPE exists during the intensification phase, how it is distributed, and the particular role it may play for the evolution dynamics. According to the WISHE theory for tropical cyclogenesis (WISHE=Wind Induced Surface Heat Exchange), the existence of CAPE is not required in the intensification process. However, this theory only leads to a conclusive result, if the net latent heating in the outer region of a tropical cyclone vanishes due to the assumption of low relative humidity. Such an assumption is not necessary when CAPE can be stored in the inflow boundary layer. The axisymmetric cloud-resolving model HURMOD and the 3-dimensional cloud model CM1 will be applied for the study. The research is based on the hypothesis that CAPE contributes to an increase in the intensification rate. This hypothesis can be verified by a simple convective parameterization scheme, in which CAPE is reduced with a prescribed time scale. When intensification also takes place with an arbitrarily small relaxation time scale, this indicates that WISHE is relevant. A conceptual model will be developed to make the effect of CAPE on intensification more comprehensible.