Entropy Flow Characteristics of Fine Structure of Typhoon CHANCHU (2006)

Based on dissipation structure theory, entropy balance equation is derived from the Gibbs relation, according to the second law of thermodynamics. The distributions of convective cells and entropy flows in upstream, midstream and downstream of spiral rainband and eyewall are examined using a high-resolution simulation data of Typhoon Chanchu(2006). The results show that the distribution of negative entropy flow is in close contact with deep convective cells. The evolution characteristics of the entropy flow accompanying with the onset, development and extinction of Typhoon Chanchu are also analyzed based on the configuration of negative entropy flow and fine structure of the typhoon. When the convective cells in the rainband move from upstream to downstream, the high value region of negative entropy flow is associated with corresponding deep convective cells. As the convective cells weaken, the absolute value of negative entropy flow decreases. When the convective cells merge and flow into the eyewall, the negative entropy flows aggregate in the eyewall and the highest negative entropy come into being, which contributes to the maintenance and development of deep convection in the eyewall. Furthermore, negative entropy flow may be a significant indicator for intensity variation of the typhoon, suggesting the systematization effect of negative entropy flow in atmospheric system.

Key words: dissipation structure; entropy balance equation; convective cells; entropy flow; negative entropy flow