选取西北地区资料年代较长的171个地面测站1961～2003年日平均气温资料,计算历年≥0℃、≥10℃积温和<0℃负积温,深入研究西北地区热量资源对气候变暖的响应及其对农业生产的影响。结果表明:1987～2003年比1961～1986年的平均值明显增高,尤以最低气温增幅最大,这说明最低气温的变化比最高气温的变化更敏感,西北地区气候变暖主要来自最低气温升高的贡献。冬季升温幅度大于夏季,<0℃负积温绝对值明显减少。西北地区20世纪80年代后期气候明显变暖,热量资源增加,喜温作物面积扩大,越冬作物种植区北界向北扩展,对牧区牲畜越冬度春有利。西北地区气候变暖对农业的负面影响大于正面影响。

Using data of 171 observations from 1961 to 2003 in Northwest China,mean monthly temperature,highest temperature,lowest temperature,accumulated temperature ≥0℃,≥10℃,and negative accumulated temperature <0℃ were collected to analyze response of climate warming on heat resource and impact of climate warming on agricultural production.The results showed that mean monthly temperature,highest temperature,lowest temperature and accumulated temper-ature ≥0℃ and ≥10℃ of 1987～2003 were significantly higher than that of 1961～1986,especially the lowest temperature increment markedly increasing and the increment of winter greater than that of summer,the lowest temperature rising played a main role on climate war-ming over Northwest China.The negative accumulated temperature <0℃ reduced obviously.As the trends of climate change appeared warming since the late 1980s in Northwest China,thermal resource increased,planting areas of heliophilous crops expanded,the planting area of north boundary of crops would extend northward which is favorable for animals to overwinter and spend spring.The negative impacts of climate warming on agriculture is greater than the positive.