近56年来西安市气温突变与致灾效应

根据1951-2006年西安逐月平均气温和逐月降水资料,采用一元线性趋势估计和5年滑动平均法分析了近56年来西安市年均温和季均温的变化趋势;采用滑动t检验法分析了气温突变的时间;并研究了西安市气温突变前后旱涝灾害的变化。结果表明:近56年来西安气温呈明显的上升趋势;该市在1994年附近气温发生明显的突变,由低于气候平均值变为高于气候平均值,其后气温持续偏高;西安市气温显著突变的时间与西北地区、长江中下游一致,早于华南和青藏高原地区,晚于东北、华北和淮河地区,更晚于全国;近56年来西安年平均气温倾向率与西北地区接近,低于东北,高于其它5个地区,及全国和全球;气温突变后,西安市旱涝灾害的比例都有所上升,但是旱灾的增幅更大,更明显。

Temperature abrupt change and disaster effects in Xi'an City in recent 56 years

Based on monthly average temperature and precipitation data in Xi'an city from 1951 to 2006,the seasonal and annual average temperature changes were analyzed by linear trend method and a five-year moving average method.The temperature abrupt change was determined by sliding t-test method.At the same time,the droughts and floods in Xi'an city around the abrupt temperature change were studied.The results indicated: the temperature was rising obviously with a bigger increasing rate in Xi'an,where had an obvious climate discontinuity near 1994 from a lower than average climate to a higher than average climate,then the temperature continued to be higher;The time of the remarkable temperature abrupt change was consistent with that in Northwestern China and the middle and lower reaches of the Yangtze River,was earlier than that in South China and the Tibetan Plateau and later than that in Northeast China,North China and the Huaihe River regions,and much later than that in the whole country;the annual average temperature tendency rate of Xi'an was close to that in Northwestern China,which was lower than that in Northeast China,higher than that in the five other areas and the nation and the globe.After the change of temperature,the drought and flood disasters' proportion increased in Xi'an city.However,the increase of drought was bigger and more obvious.