Study of entropy flow characteristics during the evolution of Typhoon Morakot

In this paper, the evolution (genesis, development and decay) of Typhoon Morakot is diagnosed in terms of entropy flow through the entropy balance equation with the NECP/NCAR reanalysis data, while the entropy balance equation is derived from the Gibbs relation, according to the second law of thermodynamics. The results show that: (1) the predominant negative entropy flow is distributed around the center of typhoon in the layer of 900 to 1000hPa, while the other area of the same level is covered with intense positive entropy flow; (2) the fields of the entropy flow during the evolution of Typhoon Morakot show that the growth of the typhoon is greatly dependent on the negative entropy flow from its surroundings, the changes of negative entropy flow match well with the development of atmospheric system; (3) the vertical spatial distribution of entropy production for Typhoon Morakot is characterized by big entropy production in a large portion of the upper levels and small entropy production in the middle levels, while the value of entropy flow is ten times bigger than that of entropy production.