近55a秦岭山区极端气温变化及其对区域变暖的影响

摘要

分析极端气温变化对气候变化研究具有重要意义.本文基于秦岭地区31个站点1960-2013年的逐日最高气温、最低气温和平均气温资料,获得秦岭地区16种极端气温指数,采用线性倾向估计法、M-K检验和主成分分析法,研究各指数变化特征,以揭示极端气温变化规律及其对区域变暖的影响.结果表明:(1)近55 a秦岭地区极端气温呈上升趋势,且日最高气温的升幅大于日最低气温;极端气温暖指数升高,冷指数降低,且暖指数的变化幅度大于冷指数.(2)日最高(低)气温极高值、日最高(低)气温极低值和气温日较差的升幅分别为0.14(0.06)、0.38(0.11)、0.08℃/10 a,夏季日数、热夜日数、暖昼日数、暖夜日数、暖持续日数和生物生长季分别以3.91、1.89、2.59、2.24、1.29、3.15 d/10 a的趋势在增加,而冰冻日数、霜冻日数、冷昼日数、冷夜日数和冷持续日数以-0.7、-3.01、-1.79、-2.05、-0.45 d/10 a的趋势在减小.(3)近55 a秦岭地区极端气温指数变化趋势与全球及全国基本相同,但变化幅度相对偏小,突变时间主要集中在20世纪90年代.(4)近55 a秦岭地区气候变暖与极端气温指数的变化关系密切,其中夏季日数、热夜日数、暖昼日数、暖夜日数和冷昼日数是秦岭地区气候变暖的主要贡献者.%Research on extreme temperature is of great significance to the study of climate change.Based on the data which were daily maximum temperature,the minimum temperature and the mean temperature observed from 31 meteorological stations in Qinling Mountains from 1960 to 2013,sixteen extreme temperature indices were obtained.Linear regression,M-K test and factor loading analysis were used to study the variation of each index,therefore to reveal the variation of extreme temperature and its impact on regional warming.The results showed that:(1) The extreme temperature in Qinling Mountains had increased remarkably in past 55 years and increasing amplitude of daily maximum temperature was more intense than that of daily minimum temperature.The extreme warm indices showed an upward trend,while the extreme cold indices showed a downward trend more importantly,the amplitude of warm indices were relatively larger.(2) The tendency rate of monthly maximum value of daily maximum (minimum) temperature,monthly minimum value of daily maximum (minimum) and diurnal temperature range were 0.14(0.06),0.38(0.11) and 0.08 ℃/10 a,respectively.The occurrence of summer days,tropical nights,warm days,warm nights,warm spell duration days and growing season length showed a significantly increasing trends at the rates of 3.91,1.89,2.59,2.24,1.29 and 3.15 d/10 a,respectively,while the occurrence of ice days,frost days,cold days,cold nights and cold spell duration days had significantly decreased by-0.7,-3.01,-1.79,-2.05 and-0.45 d/10 a,respectively.(3) The variation trend of extreme temperature indices in Qinling Mountains were as same as the global and the national trends,but the amplitude of them were relatively smaller.The mutation years were mainly concentrated in the 1990 s.(4) In recent 55 years,the climate warming in Qinling Mountains was closely related to the change of extreme temperature indices.Among all the indices,only summer days,tropical nights,warm days,warm nights and cold days were the major contributors to climate warming over the Qinling Mountains.