| Base on the statistical characteristics of daily high/low observational temperature data of 40 years from 1961 to 2000 in Nanjing area and of 46 years form 1960 to 2005 in China, the probability distribution function that can be presented for observational temperature data is constructed. Base on this probability distribution function, the following work is done:1.Using Monte-Carlo method, the inherent law of record-breaking high/low temperature events has been investigated, and on which the influence of the global warming(v=0.006℃/a)during 20th century and Nanjing regional warming(v=0.017℃/a)in nearly forty years has also been compared. Both the theoretic analysis and Monte Carlo simulation results show:(1)the most likely probability of its occurrence intensity of the K'th record-breaking high/low temperature events takes the form of linear increase with k (k =1,2,3), and the frequency of the occurrence of record-breaking high/low temperature events in a year tends to 1 (t +1) decrease with time t , and in years when the average temperature is high, the probability of the occurrence record-breaking high/low temperature events is also high/low, otherwise, the probability is low/high.(2)The result also indicates that the velocity of global warming(v=0.006℃/a)in 20th century and the rate of regional warming(v=0.017℃/a)of Nanjing area in nearly forty years are yet insufficient to alter the intensity and frequency of record high/low temperature events meaningfully. However, such velocity of warming will ultimately make the frequency of the occurrence of record-breaking high temperature events decrease gradually towards a constant, being approximately equal to the warming velocities.(3) In addition, we have also studied the effect of variances, autocorrelation between temperatures in two successive days and long-term persistance of the temperature sieries on record-breaking high temperature events,finding that the effect of different variance, weak autocorrelation or weak long-term persistance on the record-breaking high/low temperature events can be neglected.2. Based on the theory of probability distribution of record-breaking events and daily high/low observational temperature data in China form 1960 to 2005, the spatial-temporal characteristics of record-breaking temperature are investigated. We find:(1)the annual mean frequency of record-breaking high temperature is about 2.5 times more than normal in 1976-2005, which for record-breaking low temperature is 4.5 times less. Record-breaking high temperature is obvious more than normal in Northwest, North China, Northeast and Tibet, then for record-breaking low temperature which is obvious less than normal here.(2)In the relative trend of record-breaking temperature events, for record-breaking high temperature, there something increases for most part of China, but for record-breaking low temperature which become less and less all over China. Except the eastern part of Heilongjiang Province, the western part of Xinjiang, Jianghuai region, most part of Sichuan, Guangxi province, Guizhou province, Hunan province and Chongqing, which RBE of high temperature trend was not obvious, the rest most places of china show an obvious upward trend, especially most evident in central and western regions of Inner Mongolia. For RBE of low-temperature, only the northern part of Sichuan Province has been an small upward trend, the vast majority of the region of china showed a clear decreasing trend, especially in the eastern part of northeast China, central Inner Mongolia, northwest of the southern and eastern China the most obvious.(3)In the development trend of strength, for record-breaking high temperature events, it has something enhancement in high latitude areas of China, but for record-breaking low temperature events, it has no change or eventually become weakening in this place and also XinJiang and Tibet. It should to be pay attention that the strength of record-breaking low temperature events become obvious enhanced in south part of China.(4)In studying the relationship of annual frequency of record-breaking high/low temperature events and pacific warm pool index, we find that for both there are significant correlations between them for almost of China. |
PDF Full Text Request