| Based on the daily ground data of temperature and rainfall observation in Ganzi, precipitation by using Linear trend estimation, Moving average and Wavelet transform method. The change trend of temperature and extreme climatic factors are analyzed in detail, and using the Mann-Kendall method for the future trend of precipitation and temperature in Ganzi were predicted. The results show that:(1)In the study area, the linear trend of annual precipitation is +94.474mm/10 a,showed a significant increasing trend, and the five moving average curve of amplitude is also larger; In terms of seasonal precipitation, The linear trend was respectively+31.389mm/10a(Spring), +51.066mm/10a(Summer), +39.08mm/10a(Autumn),+74.81mm/10a(Winter), all increased in different degrees, 5 year moving average curve also has different degrees of fluctuation.Using the Morlet wavelet analysis obtained: there are 3a, 6a, 11.5a and 21.5a primary period in the annual precipitation sequence; spring precipitation is 5a, 11 a and23a primary period; summer precipitation exists 4.5a, 7a and 16 a primary period;autumn precipitation are 3.5a, 6a, 8.5a, 11 a, 13.5a and 23 a primary period; winter precipitation includes 5.5a, 8a and 17 a primary period.Mann-Kendall method is used to changing trend and mutation testing of annual precipitation and four seasons’ precipitation, It showed that: There are mutations in different time points, autumn and winter have more break point, the reason is autumn and winter precipitation mutation rate is bigger.(2) The annual average temperature of linear trend rate is +0.2℃/10 a in the study area, showing very obviously warming trend, and 5years moving average curve shows that: it showed overall warming trend and in recent ten years shows an approximate linear upward trend; As for seasonal average temperature, the linear inclination rate is+0.198℃/10a(spring),+0.231℃/10a(summer),+0.17℃/10a(Autumn),+0.13℃/10a(Wint er), all showed different degrees of warming trend, and 5years moving average curve showed that the temperature fluctuation trend of summer and winter three seasons larger,and spring’s weak.Using the Morlet wavelet analysis obtained: there are 3a, 6a, 10 a, 19 a and 32 a primary period in the average annual temperature; spring annual average temperature is2 a, 9a, 18 a and 31 a primary period; summer average annual temperature exists 3a, 12 a and 22 a primary period; autumn average annual temperature are 3a, 10 a, 17 a and 31 a primary period; winter average annual temperature includes 5a, 8a 15 a and 26 a primary period.Mann-Kendall method is used to changing trend and mutation testing of annual average temperature and four seasons’ average temperature, It showed that: The time point mutation of annual average temperature and four seasons’ average temperature is between 20 century and 21 century.(3)The study area of extreme climate element analysis, the annual average lowest temperature and the highest temperature have the warming trend of increasing, and the annual average lowest temperature’s warming trend is more obvious. From the analysis of Morlet wavelet with annual lowest and highest temperature, the annual average lowest temperature includes 6a, 19 a and 29 a primary period. the annual average highest temperature is 4a, 7a, 10 a, 18 a and 29 a primary period.Mann-Kendall method is used to changing trend and mutation testing of extreme climate element, It showed that: the annual average lowest temperature and the highest temperature respectively in 1998 and 2003 occurred around a significant mutation. |
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