对台风麦莎(2005)的熵流特征初步分析

根据热力学第二定律推导出熵平衡方程,并在数值模拟输出结果的基础上利用熵平衡方程中的熵流项来分析2005年台风"麦莎"发生、发展和消亡各阶段的熵流特征.(1) 从对流层的低层到对流层的高层,台风中心附近的熵流分布会逐渐由负熵流占优势互补趋向于以正熵流为主;(2) 对流层中层500 hPa的负熵流分布显示出,随着台风的强度加强(减弱),台风中心附近的负熵流强度也会随之加强(减弱);(3) 台风中心附近的负熵流分布和强度特征对于台风强度和未来移动路径有一定的指示意义.

ENTROPY FLOW CHARACTERISTICS OF TYPHOON MATSA (2005) AS SIMULATED BY A MESO-SCALE MODEL

The evolution of Typhoon Matsa (2005) is examined in terms of entropy flow through the entropy balance equation derived from the Gibbs relation, according to the second law of thermodynamics. The entropy flows in the various significant stages of its evolution (genesis, development and decay) are diagnosed based on the outputs of the PSU/NCAR mesoscale model (known as MM5). The results show that: (1) the vertical spatial distribution of entropy flow for Typhoon Matsa is characterized by predominant negative entropy flow in a large portion of the troposphere and positive flow in the upper levels; (2) the fields of entropy flow at the middle troposphere (500 hPa) show that the growth of the typhoon is greatly dependent on the negative entropy flows from its surroundings; and (3) the simulated centres of heavy rainfall associated with Typhoon Matsa match well with the zones of large negative entropy flow, suggesting that large negative entropy flow may be a significant indicator for severe weather events.