东北地区最高、最低温度非对称变化的季节演变特征

Asymmetric Change of Maximum and Minimum Temperature in the Northeast China from 1959-2002

选用东北地区剔除迁站次数较多的观测站后的74个代表站1959～2002年44年的月平均最高气温和最低气温观测数据，建立了东北地区近44年来的年、四季最高气温和最低气温序列。在所建序列基础上，分析了东北地区最高气温和最低气温的年和季节变化规律；采用Mann-Kendall和Yamamoto方法对经过滑动平均的最高气温和最低气温序列进行了突变分析。计算了所有测站的年和各个季节最高气温和最低气温的趋势系数，分析增温趋势在各季节的地域分布特征。结果表明，近44年最高气温和最低气温均表现为明显的增温趋势，最低气温的增温趋势明显高于最高气温，前者的年气候倾向率为后者的2倍；最高气温和最低气温都表现为冬季增温最强，春季次之，秋季最弱；在研究区域的中心部位，即内蒙古、吉林和黑龙江三省交界处有一范围较大且稳定的最低气温强增温区；最高气温和最低气温的突变点发生时段基本一致，强突变发生在80年代后期，较弱的一次发生在70年代初。

The date of monthly mean maximum and minimum temperature are obtained in 74 stations in Northeast China, after minimizing the posssible effect of urban heat island from 1959 -2002. The time series of maximum and minimum temperature for the area are got by averaging the 74 station values for the period. The temperature time series were further analyzed for the change characteristics on year and season in the area. The climate jumps of annual extreme temperature series, by dealing with slippage, were tested by both Mann-Kendall and Yamamoto method during the past 44 years in Northeast. The coefficients of extreme temperature trends were calculated in all stations and all seasons, and the characteristics of terrain distribution of increasing trend were analysed in each season. The results show that asymmetry is detectable in all seasons. Though both maximum and minimum temperature is increasing for the period. Tmin increase more than Tmax in all parts of Northeast China. The former doubles the latter. Their increases are biggest in winter, second in spring, least in autumn. In the center, there is a strong increasing temperature area, bigger and steadier in range.