1961-2005年东北地区气温和降水变化趋势

Abstract

利用东北地区96个气象站1961-2005年的日平均气温和日降水量资料,采用线性倾向率法,累积距平法,Mann-Kendall法和Morlet小波分析等方法,对东北地区近45年来的气候变化和突变现象进行了研究。结果表明:近45年来,东北地区年平均气温变化在2.45-5.72 ℃之间,年均温呈现显著上升趋势,气候倾向率为0.38 ℃/10 a(<em>P</em><0.01),1988-1989年间发生了由低温到高温的突变;东北地区四季平均气温均呈现增高的趋势,其中冬季气温增幅最大,气候倾向率达到0.53 ℃/10 a,夏季气温增幅最小,0.24 ℃/10 a。东北地区年均温和季节均温年代际变化亦呈现明显的增暖趋势,年均温,春季均温和冬季均温均在1981-1990年开始变暖,夏季均温和秋季均温在1991-2000年开始变暖。东北地区气温增暖幅度随纬度的升高而增大,大兴安岭北部和小兴安岭地区是增温最明显的地区,增暖幅度较小的地区为辽河平原,辽东半岛和长白山南部地区。东北地区年降水量变化在430.40-678.72 mm之间,降水量变化趋势不明显,整体呈现减少趋势,气候倾向率为-5.71 mm/10 a(<em>P</em>>0.05),1981-1990年为降水最多的年代,1982-1983年间发生了降水量由少到多的突变。四季降水量变化呈现不同的趋势,其中春季和冬季降水量呈现增多的趋势,夏季和秋季降水量呈现减少的趋势。降水量减少较明显的地区为辽东半岛和长白山南段,降水量增多较明显的地区为大兴安岭北部和松嫩平原。Morlet小波分析结果表明,东北地区年平均气温存在11 a的强显著周期,此外还有24 a和6 a尺度的变化周期;东北地区年降水量存在16 a的强显著周期和6 a的小尺度变化周期。通过以上分析,近45 a东北地区总体气候呈现明显暖干化趋势。;Northeastern China is one of the regions that would be mostly affected by the changing climates, and created the particular climate pattern and characteristics under climate changes. The pattern and characteristics of climate changes in Northeastern China was analyzed with the methods of the linear regression method, cumulative anomaly method, Mann-Kendall test method and Morlet wavelets analysis method based on daily average air temperature and daily precipitation data observed at 96 meteorological stations covered the Northeastern China from 1961 to 2005. The linear regression method was used to study the variation trends of mean temperature and precipitation on annual-scale and seasonal-scale in recent 45 years. The cumulative anomaly method and Mann-Kendall test method were used to test trends and abrupt changes of annual mean temperature and precipitation. The Morlet wavelet analysis method was used to detect the change interval of annual mean temperature and precipitation. The linear trend rates for annual and seasonal mean temperature and annual and seasonal precipitation were calculated at each meteorological station. Those rates were then interpolated using inverse distance weighted (IDW) interpolation to reveal their spatial distributions. The results showed that the climate in this region showed a significant warming trend, the annual mean temperature varied between 2.45 ℃ and 5.72 ℃,and the annual mean temperature has increased by 0.38 ℃/10 a (<em>P</em><0.01) in recent 45 years, and an abrupt change from low temperature to high temperature occurred in 1988-1989. In addition, all of the seasonal temperatures showed increasing trends, and the increase of temperature in winter were higher (0.53 ℃/10 a) than in the summer (0.24 ℃/10 a). The decade change of annual and seasonal mean temperature also showed spatially increasing trends and the higher the latitude, the more obvious the increasing trend. The calefactive range was larger in the northern Da Hinggan Mountains and Xiao Hinggan Mountains, and it was smaller in the Liaohe Plain, Liaodong Peninsula and southern Changbai Mountain. The annual precipitation varied between 430.40 mm and 678.72 mm,and the annual precipitation showed a decrease trend in recent 45 years, and decreased by 5.71 mm/10 a (<em>P</em>>0.05), the precipitation in 1980s was more than in the other decades, and the abrupt change in precipitation occurred during in 1982-1983. The seasonal precipitation showed various trends, the spring precipitation and winter precipitation showed increasing trend, but the summer precipitation and autumn precipitation showed decreasing trend. The Liaodong Peninsula and southern Changbai Mountain showed significantly decreasing trend in precipitation, whereas, the northern Da Hinggan Mountains and Songnen Plain showed obviously increasing trend. The climate change interval analysis revealed that the annual mean temperature fluctuated significantly with the interval of 11 years, 24 years and 6 years, and the annual mean precipitation fluctuated with interval of 16 years and 6 years, respectively. For this region, the climate was trended to be warmer and dryer in recent 45 years and the temperature and the precipitation showed different interval.