宜昌市主要气候要素及极端事件变化趋势研究

Trend of main climatic factors and extreme values in Yichang

根据宜昌市1952年～2008年57年间21个主要气候要素及其极值资料,通过趋势分析和年代际比较,揭示宜昌市气候变化对全球气候变化和当地城市化的响应.结果表明:1)宜昌市6项气温因子中,有4项为升温趋势,2项为降温趋势.其中年平均最低气温、极端最低气温、年平均气温极显著上升,1970年代中后期升温速度加快;年极端最高气温和37℃以上的高温日数表现下降趋势.2)年降水量、降水日数均为减少趋势,而年最大日雨量、暴雨日数为弱增加趋势.年平均相对湿度显著减小,年最小相对湿度以1970年代为界,先增后减.3)年平均风速、极大风速、最大风速及大风日数均一致性减小,后两项为极端显著减小;4)年日照时数下降趋势显著.5)年雾霾总日数、轻雾日数、霾日数均极显著增加,而年大雾日数显著减少.可见宜昌市大部分气候要素变化显著.

Based on the 21 series of main annual climatic factors and extreme events during 57 years in Yichang from 1952 to 2008, the features of main annual climatic factors in Yichang responding to global climate change and local urbanization are revealed through trend analysis and decadal comparisons. Results show that：1） Four temperature factors have shown a consistent warming trend, and the others are with downward trend. Among them, the mean minimum temperature , extreme minimum temperature and annual mean temperature increased extremely significantly, Warming progress got faster in the middle and late 1970＇s. The extreme maximum temperature and the days of daily maximum temperature ≥ 37 ℃ have shown downward trend. 2） Annual rainfall and rain days have showed a consistent descending trend while maximum daily rainfall and the number of heavy rain days have showed increasing trend weakly. The Annual mean relative humidity was reducing obviously. Annual minimum relative humidity increased before 1970 and reduced since then. 3） The mean, extreme and maximum wind velocity and days with strong wind have shown consistent reducing trend. Among them, maximum wind velocity and days with strong wind are reduced extremely signifieantly. 4） annual sunshine hours showed downward trend significantly. 5） The annual total numbers of fog and haze, the numbers of mist ,the numbers of haze have increased extremely significantly. On the contrary, annual days with fog have a significant reduction. Above all, most of annual climatic factors and extreme events have obvious trend in Yichang in past 57a.