我国东北地区主要城市气温和降水量序列的多尺度分析

根据1961~2010年东北地区35个主要城市站的逐日气温及降水资料,采用线性拟合、小波变换、经验正交函数分解、Mann-Kendall突变检验和R/S分析等方法,分析了我国东北地区主要城市的气温和降水的变化。结果表明:近50年东北主要城市年平均气温呈上升趋势,其中20世纪80年代后期至90年代初增温幅度最大;城市气温变化存在明显的16a尺度年代际变化周期和(7~8)a、4 a和准2 a尺度的年际变化周期,其中4a尺度的低频振荡能量最强;城市化进程对气温变化影响显著。东北地区主要城市的年降水量减少趋势明显,其中20世纪60年代中期至80年代初降水减少幅度最大;年总降水变化存在准2 a、4 a和(9~10)a尺度的年际变化周期,其中4 a和(9~10)a振荡能量最强;夏季出现特涝的概率大于特旱,大涝的几率小于大旱;同时7月份是东北局部特大洪涝或干旱的多发时段。

Multi-time Scale Analysis on the Variations of Temperature and Precipitation of Main Urban in Northeast of China

The daily temperature and precipitation data of thirty-five urban meteorological stations in Northeast of China were selected from 1961 to 2010. Using method of trend analysis, wavelet transform, EOF transform, Mann-Kendall test and R/S analysis, this study analysis the tendency of temperature and precipitation changes for the major cities in northeast of China, the main findings are as follows: in recent 50 years, the annual mean temperature demonstrate a significant increase trend and the extent of most increasing temperature in the late 1980s and early 1990s. Using the power spectral examination, the annual average temperature of northeast main urban had significant periods of time scale, with 16 years, 7-8years, 4years, and quasi-2years. The 4years period of time scale is obvious. The influence that procedure of urbanization caused the changes of temperature is obvious. Furthermore, the annual precipitation demonstrates a significant decrease trend and the extent of most decreasing precipitation from the 1960s to early 1980s. Using the power spectral examination, the annual precipitation of northeast main urban had significant periods of time scale, with quasi-two years, 4years, and 9-10 years. The 4 years and 9-10 years period of time scale is obvious. In summer, special flood is greater than the probability of special drought, floods chance is less than the drought. In July, it is the period of high incidence when local floods or drought-prone period is common within main urban in Northeast of China.