近50年西峰气候变化特征分析

Climate change analysis in the last 50 years in Xifeng City

根据西峰1951-2001年51a系列的降水和气温实测资料对气候变化进行了分析。分析表明，1976年以前，年降水量有增加趋势，1976年以后，年降水量呈下降趋势，年均气温和年最低气温呈线性升高趋势。利用年降水量和年均气温距平百分比累计分析表明，西峰气候变化可以分为凉干期、凉湿期、暖湿期和暖干期等四个阶段。不同月份逐年气候变化分析结果表明，冬季和初春降水量增加，7、8、9三个月的降水量呈下降趋势。各月平均气温和最低气温均呈增加趋势。从气温变化季节特征分析，冬季暖湿化趋势明显，在初春季节最高气温下降，在降水较多的夏秋季节，气候显示为暖干化趋势。

The climate change in Xifeng City, Gansu Province is analyzed, based on the precipitation and temperature data from 1951 to 2001. It is shown that before 1976, the annual precipitation tended to be increased, and after 1976, it tended to be decreased; and the average annual temperature and average lowest temperature was increased significantly. The analysis on the accumulative anomaly of annual precipitation and temperature shows that there are four remarkable climate change stages, including cool and dry stage, cool and wet stage, warm and wet stage and warm and dry stage. The monthly precipitation and temperature change differently. The precipitation increases in winter and early spring while it decreases in July, August and September. The average monthly temperature and average lowest monthly temperature increase significantly. The warm and wet trend is clear in winter, while in the wet period of summer and early autumn, the climate shows a warm and dry trend.