Study Precipitation And Temperature Changes In Xi’an Area

In this paper, seven countries in Xi’an General Stations from1970to2013daily basic meteorological data used to draw the spatial distribution maps combined with Golden software Surfer8and vb prepared Xi’an precipitation, temperature, automatic drawing software, and through the DPS data processing system, SPSS Statistics, MATLAB and Excel data analysis and processing.The annual, seasonal and monthly variations in Xi’an44years of precipitation and temperature changes and tmperature changes in weather-related disasterswere were analysed. The main results are as following:(1)Precipitation varies around612mm.Ratio of wet years/dry years is6/5,compared with an increase along the Qinling Mountains foothills city station.Sudden change of precipitation from large quantity to small and from small quantity to lage appeared in1992and2002,respectively. There is change cycle shocks of2years,4years and12years in recent years and rainy days are decreasing.Summer spatial distribution of thin,dense winter,spring and autumn are obvious than partial drying trend.The trend is clearly humid summer than in winter.There is a big difference between month to month with a rate of101mm.The rapid increase is in June and July,reaching its peak.A rapid decline occurs in October.Precipitation in March is the most abnormal in Huxian but other months are up to Lam Tin Station.There are slightly more rainy days in Huxian and Lam.Rainy days slowly rses from Jan to May and volatility rise from May to October,then reaches its peak after the Sept and sharp declines in December.(2)Warm temperature rises to the current period.The fitting growth rate is0.365℃/10a.The historical low point occurred in1985and the high point in2013, a difference of2.88℃.High temperature year was quite to low temperature year.Temperature mutated in1994, mutation increased up to the maximum in2000, there was a significant24senior cycle.Because of the climate of Qinling Mountains foothills, the temperature of southern is low. Because of the urban heat island,the temperature of city is highest. The largest increase in spring.The spatial distribution of winter is relatively thin, summer intensive.The spatial distribution of monthly minimum is Lantian except September of Changan, The city highest from March to September. Huxian highest from October to February. Spring and summer average ground temperature decreases with increasing depth, winter contrary.The maximum temperature of the ground was slightly decreased, the minimum increasing.Air temperature rise reasons for ground temperature rise mainly. Geothermal influence of air temperature on the ground temperature increases with depth in the reduced.Comprehensive analysis of precipitation and temperature, the southern cold and rainy,northern high temperature and few rain, the climate of Xi’an and Huxian closer.(3)Precipitation and temperature-related severe weather change analysis indicates that Xi’an is belong to high-temperature-prone areas.Drought occurs mainly in spring and autumn and winter. Storm occurs mainly in summer.Storm frequency occurred mostly in2011.Frequency of storm increased in the early1970s to the1990s.Rainstorm frequency tended todecrease in the1990s to the early2000s. Heavy rains appear to reduce.Recent rainstorm frequency tended to increase. Heavy rain is more in in south than than in the north.