陕北黄土高原地区极端气温事件变化特征

为了分析区域气温变化对全球气候变化的响应过程，利用6个气象站点1959—2011年逐日最高、最低和平均气温数据，分析陕北黄土高原地区极端气温事件变化特征。结果表明：（1）变化趋势上，区域内极端气温暖指数（极端最高气温、生长季长度、暖夜日数和暖昼日数）呈显著增加趋势，而极端气温冷指数（霜冻日数、结冰日数、冷夜日数和冷昼日数）呈显著减少趋势，极端气温指数变化趋势与全国趋势一致；（2）空间分布上，榆林和吴起是极端气温指数最大值和最小值分布较为集中的2个站点，反映出区域北部和西部对气候变化的响应较为敏感；（3）突变特征上，极端气温冷指数（结冰日数、冷夜日数和冷昼日数）减少突变主要发生在1980s，而暖指数（极端最高气温、生长季长度、暖夜日数和暖昼日数）增加突变主要发生在1990s。

Characteristics of Extremely Temperature change Trend in Loess Plateau Area of Northern Shaanxi Province

In order to analyze change process of regional temperature response to global climate change, daily maximum, minimum and average temperature data of six meteorological stations from 1959 to 2011 were used to analyze the change characteristics of extreme temperature in Loess Plateau area of northern Shaanxi province. Result shows: (1) on the change trend, warm index in the region, like extreme maximum temperature, length of growing season, warm night days and warm day days, showed a significant increase trend, while cold index in the region, like frost days, freezing days, cold night days and cold day days, was significantly decreasing trend. Those trend of extreme temperature index is consistent with the national trend. (2) in spatial distribution, the maximum and minimum value of extreme temperature indexes distribution was more concentrated in Wuqi and Yulin station, which reflects that it is sensitive to climate change in the north and west region of Loess Plateau area in northern Shaanxi province. (3) on the abrupt change years, the cold index in the region like freezing days, cold night days and cold day days was reducing mutation occurred in the 1980s, while the warm index in the region like extreme maximum temperature, length of growing season, warm night days and warm day days was increasing mutation occurred in the 1990s.