Variation Characteristics Of Typhoon Frequency And Its Statistical Distribution

Typhoon disaster is one of the main natural disasters in our country. With the further process of reform and opening up, especially with the developing of the coastal area economic exploitation, ocean disasters threat to the safety of lives and property seriously that induced by high water level and sea wave height in typhoon process. So it is important greatly to study the characteristics of typhoons occurrence.In this paper, with the typhoon data from 1949 to 2001, statistical analyses were performed to study the mterannual and interdecadal variation of the Northwest Pacific typhoon and landing typhoon on over China. Results show that, firstly, Northwest Pacific typhoon and landing typhoon on over China show mterannual and interdecadal differences obviously. Secondly, interannual variation has relationship with ENSO.Typhoon Frequency Maximum Entropy model is proposed according to the principle of maximum entropy. The actual example calculation shows that the model fit the existing data well. At the same time, the maximum entropy model keeps the uncertainty of the unknown data. And at the base of one dimensional compound extreme value distribution theory, one kind of uncertain probability -Typhoon Maximum Entropy-Gumbel Compound Extreme Value model is proposed. This model includes the occurrence frequency of special weather process that leads to extreme sea state and Gumbel Probability Distribution model. The main jobs of this thesis are stated as follows:1. The study on the utmost possible value of typhoon occurrence frequency is transformed into the research on the most possible value calculation of typhoon frequency maximum entropy.2. Based on the measured data and its constitutive constraint condition, the least prejudice probability distribution is got that makes the entropy function reach maximizing. Its parameters are expressed explicitly in terms of the distribution moments of the typhoon occurrence frequency.3. Considering the occurrence frequency of special weather process that leads to extreme sea state, Typhoon Maximum Entropy-Gumbel Compound Extreme Value model is derived based on compound extreme value theory.