长白山地区近50年平均最高和最低气温变化

利用线性趋势法对长白山地区13个气象台站建站以来的逐日温度资料进行分析，确定该区域的气温变化趋势，同时通过Mann-Kendall方法确定突变点位置，并结合t检验法进行检验。结果表明:区域的年平均最高气温和最低气温都有极为显著的增加趋势，分别为每10年增加了0.23和0.46℃（α=0.001）；近50年的最高气温和最低气温的时间系列都有一个突变点，其中最高气温的突变点出现在1995年左右，最低气温的突变点在1985年前后。这种变化使得温度日较差表现出明显的减小趋势，并在1972年出现一个突变点，前后平均相差0.8℃。区域各月最高、最低气温及气温日较差与日照百分率均有极为显著的相关关系，一定程度上反映了温室效应持续增强的迹象。 

Changes in the mean maximum and minimum temperatures in Changbai Mountain,northeastern China in the past 50 years.

Using data of daily air temperature from 13 weather stations in the Changbai Mountain since establishment, the authors used the linear trend function to analyze the climatic trends in temperature. The authors also performed t tests in combination with the Mann kendall function to examine the points with abrupt changes in temperature. The results showed that asymmetry was detectable in all months, i.e., the maximum and minimum temperatures had a continuously increased trend (with a significance level of α = 0.001 confidence degree). However, the increasing rate in the minimum temperature (0.46℃/10 yrs) was faster than that of the maximum (0.23℃/10 yrs). The abrupt changes in the minimum and maximum temperature occurred in 1985 and 1995, respectively. The decrease in diurnal temperature ranges resulted from the asymmetric changes in the maximum and minimum temperatures, reflecting a continuous increase in greenhouse effects.