Analysis Of Climate Change Characteristics In The Desert-loess Transition Zone In Recent 60 Years

Desert and loess transition zone has unique geographical environment,production and living conditions. The region’s response to global change is very sensitive. Especially in nearly 60 years, the trends, characteristics and the regular of climate become the focus of research. In this paper, it uses the data from weather stations of desert and loess transition zone and its adjacent areas and analyses the change process and characteristics of the temperature and precipitation, the space distribution features of two elements, understanding the regular of climate change. The conclusion mainly include:(1) During 1960 and 2013, the annual average temperature rose as a rate of about 0.34 ℃/10 a in the study area, while the annual precipitation dropped at a rate of about 4.85 mm /10 a, with a warm-dry trend in the whole.(2) The annual average temperature mutation happened in 1990 in the study area, compared to the period before mutation(from 1960 to 1989), the temperature increased 1.08 ℃ after mutation(from 1990 to 2013). The annual average precipitation significant mutation did not occur in the research zone.(3) On the 10 years scale, temperature was low in the period of1960-1969, 1970-1979 and 1980-1989, while it was high in the period of1990-1999, 2000-2009 and 2010-2013. It was rainy in the the period of1960-1969 and 2010-2013, second in the 1970 s, it rained less in the period of1980-1989、1990-1999 and 2000-2009. From the period of 1960-1969 to the period of 2010-2013, it has experienced the climate change process of cold wet, cold wet, cold dry, warm dry, warm dry and warm wet in the study area.(4) According to the season scale, the temperature of the four seasons were on the rise, winter temperature rose fastest(0.50 ℃/10 a), it rose slowest in summer(0.24 ℃/10 a), the increased rate of spring was 0.36 ℃/10 a, it was0.29 ℃/10 a in autumn. Four seasons had different precipitation changeregular, spring, summer and autumn precipitation respectively dropped by the rate of 1.05 mm/10 a, 1.10 mm/10 a and 3.08 mm/10 a, winter precipitation rose at a rate of about 0.37 mm /10 a. Winter climate become warm and wet,spring, summer, autumn climate tended to be warm and dry.(5) On the spatial distribution, the temperature during 1960 and 2013 was high in the northwest and southeast region, low in the southwest and northeast, the central region was a transition zone. In the period of 1970-1979,in the southeast, northwest, central region and the west of northeast of the study area, the temperature increased apparently, while it decreased slightly in southwest. In the period of 1980-1989, in northwest, west of northeast, east of southeast and central region, the temperature increased obviously. In the period of 1990-1999 and 2000-2009, temperature of the whole district increased significantly. Temperature of the whole district decreased from2010 to 2013. The precipitation was become less from southeast to northwest during 1960 and 2013. The precipitation in most area decreased in the period of 1970-1979 and 1980-1989. The precipitation in most area increased in the period of 1990-1999, it increased obviously in northeast and northwest areas,decreased slightly in southeast. In southeast region, precipitation increased obviously, but reduced in many parts of the northwest in the period of 2000-2009. During 2010 and 2013, in most parts of the southeast area, rainfall significantly increased, precipitation reduced in the northwest corner.(6) The average temperature of El nino years was higher than the average temperature from 1960 to 2013.The average precipitation of El nino years was less than the average precipitation from 1960 to 2013.The average temperature of La Nina years was lower than the average temperature from1960 to 2013.The average precipitation of La Nina years was more than the average precipitation from 1960 to 2013.