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The Extreme Temperatures Of Temporal And Spatial Distribution And Variation Characteristics Analysis In Arid Regions Of Northwest China

Posted on:2014-04-23Degree:MasterType:Thesis
Country:ChinaCandidate:X Y HanFull Text:PDF
GTID:2250330422958172Subject:Physical geography
Abstract/Summary:PDF Full Text Request
As the global warming becomes indisputable facts, to temperature, especiallyresearch in extreme temperature gradually become a hotspot part. Using83meteorological stations daily temperature data in arid regions of Northwest China,taking1961-2010as research time, collecting extreme temperature, averagetemperature and correlative index to do mean treatment, through the linear trend rate,the percentile method, M-K method to get temporal and spatial distribution and itschange characteristics specific about extreme temperature in arid regions ofNorthwest China northwest. The main conclusions are as follows:1.By percentile for each temperature indicators are processed to determine thethreshold value of the extreme temperature index, to come to the extremetemperatures and extreme events.2.The arid regions of Northwest China average annual temperature is9.2℃,nearly50years showed a rising trend, the growth rate0.25℃/10a,1994mutated,upward trend is significant. The annual average temperature in higher latitude isrelatively low, the basin area between mountainous area showed an obvious different.3.The growth rate of the average temperature in the biggest of the four seasonsis autumn, minimal for the summer. Autumn season mutation and temperaturesignificantly increasing since the1980s. Spring, autumn in west greater than the east,the southern is greater than the north. On the edge of the basin, river valley and gobiarea is greater than near the mountain area in summer, south higher than north inwinter, has clear difference on the northeast, southwest, the east is greater than thewest.4.Years of extreme high temperature rise, growth, at a rate of about0.066℃/10a,mutation obviously since1987. Extreme high temperature days showed a trend ofobvious rise, the growth rate of1.54d/10a. Space on the west than the east, southernmargin of the basin is greater than the north rim. Annual high temperature days alsoshows ascendant trend, rising since1996, gobi desert around than higher latitude ormountains by near the site.5.The four seasons of extreme high temperature were rising trend, autumngrowth largest and winter minimum, extreme high temperature days in autumnshowed a growth rate, the winter days, at least, consistent with the number ofmutations in extreme heat, and days of extreme high temperature distribution in the northwest, basin edge of the southeast, the edge of the desert and gobi areas, thenorthern region is smaller.6.The average annual extreme low temperature tend to rebound warming, with0.14℃/10a rising trend, extreme low temperature rising. Warming trend is moreobvious and has risen steadily in1975. Since1984, extreme low temperature dayswere decreased significantly; Distribution in north is significantly lower than thesouth. Extreme low temperature day in annual in north is greater than the south,northeast greater than southwest.7.In addition to a slightly colder in winter, other seasons all has a warming trend,the extreme low temperature days began to decrease, summer is most prominent,days in winter also has a decreasing trend; extreme low temperature in arid regionsof northwest present a northwest-southeast direction distribute, mainly in thenorthwest area of the Tianshan Mountains, Hexi corridor and the high altitude sites.Extreme low temperature days distribution in site which near the basin, themountains surrounding, the Hexi corridor nearby.8.The extreme low temperature days during the spring and summer have a greatnegative correlation with annual average temperature, and significantly; In extremeheat has correlation with annual average temperature; Year, seasons of extreme hightemperature days were correlation with annual average temperature and prominent.
Keywords/Search Tags:extreme temperature, temporal and spatial distribution, arid regions ofNorthwest China
PDF Full Text Request
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