Formulation and Sensitivity Analysis of a Nonhydrostatic, Axisymmetric Tropical Cyclone Model

摘要

As the coverage and frequency of tropical observations increased during and after World War II, so did our understanding of the fundamental atmospheric and oceanic conditions that limit tropical cyclone intensity. For instance, Palmen (1948) discovered that if the sea surface temperature is less than 26-27 deg C, the latent and sensible energy inputs from the ocean surface will not support tropical cyclone development or intensification. Others found that the interaction of a tropical cyclone with its surrounding environment also affects intensity. Specifically, Riehl (1948) observed that the interaction with the divergent flow of an upper-level ridge increases the intensity of the tropical cyclone by enhancing the low-level convergence and the development of deep convection. However, as shown by Gray (1968), if the vertical shear between the low-level vortex and upper-level flow is excessive, the tropical cyclone will not develop or intensify. Under these conditions, the deep convection is well ventilated, and is unable to sustain the temperature and moisture anomalies that support the thermal balance of the vortex and the undilute ascent of moist convection, respectively. If we understand the conditions that limit intensity, can we then predict the maximum possible intensity for a given set of conditions.