Climate Change Characteristics Of Precipitation In The West Region Of China

The climate change characteristics of precipitation in the west region of china have been analyzed and studied comprehensively based on the data of yearly ,seasonal,monthly precipitation sequence and the number of rainy days on yearly .seasonal and temperature departure sequence of the Globa ,the Northern Hemisphere during the period of 1961 to 2000 at 109 stations in the West region of China.Results show that the spatial distribution of the precipitation of the west isvery uneven and obviously different in every quarter; the characteristics ofprecipitation is droughty and less-rain in almost all part in winter.plentiful insummer,spring and autumn are transition phases,rainfall of autumn is more than that of spring in the most of region; relative variability of each season rainfall is bigger than that of year,the variability is biggest in winter,but smallest in summer .alike between spring and autnmn and comprative in numerical value; the area of least precipitation is in TALIMU BASIN and the northwest of CHAIDAMUBASIN, not in the northwest of China.The positive load take absolutely advantage in the first spatial pattern of year and seasons .especially that the precipitation field load of winter is all positive.not in the southwest of china because of Southwest Monsoon etc.system; the characteristics of the second spatial pattern are that most of the area is taken up by positive load in year and four seasons, the west of TALIMU BASIN is the center of negative load of the year ,spring and autumn vector fields; East of ZHUNGEER BASIN is the center of positive load of the third spatial pattern of year, spring, summer and winter, the center of negative load is often in east of CHAIDAMU BASIN, but the distribution center of autumn is in east of ZHUNGEER BASIN; the distribution of the fourth spatial pattern is difficult to describe and forms several centers of positive and negative load;several centers of positive and negative load also appear,the distribution of load fields of the fifth spatial pattern of year, spring and winter represents the situation of '+,-,+' from southeast to northwest; the complexity of the sixth spatial pattern is more stonger than that of the fourth and the fifth spatial pattern, several centers of load fields of year and each season often appears inverse situation of the positive and the negative load.but the centers are still most in ZHUNGEER BASIN , CHAIDAMU BASIN and TALIMU BASIN. The variational trait of the first temporal coefficient is that the coefficient is often positive in 1960s, often negative in 1970s, the break point often happen in 1960s and 1970s, especialy 1970s; the fluctuate of the second temporal coefficient of year .spring and autumn appears little change, but appears much change of summer and winter, the break point often happen in 1980s and 1990s, specially 1980s; the change trend of the third temporal coefficient is not obvious during 1961 to 2000,only appears clear raise in the anaphase 1990s; itis difficult to detail the positive and negative trend of the fourth temporal coefficient, the situation of the coefficient appears alternant change of positive value and negative value, the break points happen concentratively in 1990s, the situation of the fifth temporal coefficient is like the fourth's ; the alternate of positive value and negative value of the sixth temporal coefficient is obvious, then the negative trend take advantage after 1990s, the distribution of the break point is even, but most of them still in 1990s; the break points happen many times ,but it is limited that the break points attain 0.05 significance test.Most of the spatial patterns don't exsit outstanding periods, specially the spatial pattern of year precipitation, the first six spatial patterns don't exsit outstanding periods, if exsit, the periods are also relative short, the most master period is about 3 years, secondly about 5 years.The precipitation of the west of china is relative less in 1960s for year and seasons, relative to 1960s, the precipitation of 1990...