Abstract:

Based on R/S analysis,the average temperature,average minimum temperature,average maximum temperature in winter (January),spring (April),summer (July),autumn (October) and the whole year,the extreme minimum temperature in winter (January) and the whole year,the extreme maximum temperature in summer (July) and the whole year,the precipitation summer semiyear (the summation of monthly statistic of April to September),winter semiyear (the summation of monthly statistic January to March and October to December) and their annual values from 1951~2002 in Chengdu were calculated.It was shown that the Hurst index of all parameters were beyond 0.5,indicating that they all had evident Hurst phenomena.The climate changes in Chengdu City had a persistence trend component.Firstly,the tendency and the relative longterm feature expressed by five climatic factors,the annual average temperature in Chengdu city,average minimum temperature and so on,all indicated that the climate would be warmer in Chengdu city.According to climate tendency,the annual average temperature in Chengdu City would increase 025°C every ten years,the average minimum temperature would increase 014°C every ten years,the average maximum temperature 004°C every ten years,the average minimum temperature 054°C every ten years,and the average maximum temperature 013°C every ten years.The rise of annual average temperature,annual average minimum temperature and annual average maximum temperature showed an obvious pattern of rising.But the annual amount of precipitation in Chengdu city would decrease continuously.The annual amount of precipitation would decrease 4520 mm and in semiyear would decrease 4124 mm every ten years.The decrease of the amount of precipitation was a consistent pattern.

Key words: climatic change, R/S analysis, Hurst index, Chengdu City