1961-2013年东北区域极端气温的变化特征

为研究东北地区极端气温变化规律，利用1961-2013年最高、最低气温资料，采用线性趋势分析方法，从时间变化、空间分布、发展趋势、指数强度方面对极端气温指数绝对及相对变化的影响等角度分析了我国东北区域极端气温事件的变化规律。结果表明：东北区域冷指数减小，暖指数增大，指数强度越大，其绝对变化越小而相对变化越大；高强度极端气温对温度变化的贡献大于低强度极端气温；高强度极端气温指数变化率增加幅度大于低强度指数，冬季各指数变化率最大；结冰日数、冷昼日数和暖昼日数变化率在东北区域的南北两侧较大；研究时段内，夏季日数、炎热夜数、暖昼日数和暖夜日数增加的幅度不断增大；霜冻日数、结冰日数、冷昼日数和冷夜日数减少的变化率先增大后减小。

Variation characteristics of extreme temperature over northeast China during 1961-2013

The variation characteristics of the extreme temperature in Northeast China were studied based on the dataset of daily maximum and minimum temperature during 1961-2013 with the main study method of linear trend analysis. This study focused on the temporal variation, spatial distribution and trend development of the indices, the impacts of the intensity of extreme temperature indices on its absolute and relative change. Results show that the cold indexes have decreased and the warm indexes have increased. The more extreme the event is, the smaller the magnitude of absolute changing rate is, and the greater the magnitude of relative changing rate is. The contribution of the extreme temperature with higher intensity for the change of temperature is larger than that with lower intensity. The increase of changing rates with high intensity is greater than that with low intensity. The magnitude of the changing rate is greatest in winter. The changing rates of ice days, cold days and warm days are greater over the south and north part of Northeast China. The magnitude of changing rates of summer days, tropical nights, warm days and warm nights are increasing monotonically during 1985-2013, and the magnitude of changing rates of frost days, ice days, cold days and cold nights go through an increasing and decreasing process.