The Regional Difference and Abrupt Events of Climatic Change in Tianshan Mountains during 1960-2010

The data of monthly temperatures and precipitations during 1960-2010 from the 27 meteorological stations in the Tianshan Mountains,combined with DEM data,are used for the analysis of the temporal and spatial trends of climate changes,including some abrupt changes.As shown in the results:(1) annual average temperatures have shown a clear upward trend,with more dramatic temperature increases in the years of this century.The seasonal averages are changing in a similar fashion with the annual averages,with the winter averages showing the highest increases and the summer averages the lowest increases.The east side of the mountains shows the most striking trend of temperature increase,and temperature change on the north is more than that on the south.(2) Precipitationshave kept increasing since 1960’s,and the increase accelerates after 1980’s.Summer precipitations show the biggest increase,and spring precipitations show the smallest increase.The annual precipitation in the mountain regions are mainly contributed by summer and spring.In the spatial scale,the mountain climate shows atwo-centerpattern,with a center ofhot and dryon the east,and a center of warm and weton the northwest,and the contrast between the two is in the trend of expanding.(3) Abrupt changes in temperature and precipitation in the mountain regions are not evident.Spring and summer temperatures may have had abrupt changes in late 1990’s to early 2000’s,while abrupt changes to autumn and winter temperatures may have happened during 1990’s.There may be an abrupt change of annual temperature on the south and east side in 1982,on the north side roughly in 1990.An abrupt change of autumn precipitation occurs in the late 1980’s,but for other seasons there are not obvious abrupt changes.Annual precipitation has an abrupt change in the late 1980’s.