近50年重庆市气候干湿变化时空特征

以重庆市34个气象站点1961—2011年降雨、气温、相对湿度等资料为基础,计算了近50 a全市的湿润指数。运用Kriging法将年均气温、降雨和湿润指数的倾向率和倾向系数进行空间插值,并对反映气候干湿变化的年气温、降雨量和气候湿润指数等时空特征进行了分析。结果表明:①近50 a,重庆年均气温呈波动上升趋势,上升速率为0.09 ℃/(10 a),空间分布上年均气温呈现由西南向东北升高,但整体差异不显著;②降雨量呈波动下降趋势,年均降雨量倾向率为15 mm/(10 a),空间上有从东南向西北递减的趋势;③重庆市湿润指数总体上略有下降,其空间特征表现为由东南向西北逐渐趋于干旱,下降幅度呈由东南向西北递减趋势,但总体差异性不显著;④气温、降雨与湿润指数相关系数分别为-0.465和0.950。

Spatio-temporal Characteristics of Dry-wet Condition in Chongqing in the Past Five Decades

The relative humidity indexes in the past five decades are calculated based on the annual precipitation and temperature data from 34 meteorological stations from 1961 to 2011 in Chongqing. Moreover, Kriging spatial interpolation is conducted for the tendency and tendency coefficients of annual average temperature, rainfall and humidity index in each decade, and on this basis, the temporal and spatial variation characteristics of annual average temperature, precipitation and humidity index which reflect the wet and dry conditions in Chongqing are analyzed. Results show that 1) in the past five decades, the average annual temperature of Chongqing rose with fluctuations, with a rising rate of 0.09 ℃/(10 a), whereas in terms of spatial distribution, the trend rose from the southwest to the northeast yet with insignificant difference; 2) average annual precipitation showed a volatile downward trend with the tendency coefficient of 15 mm/(10 a), and in terms of spatial distribution the trend decreased from the southeast to the northwest; 3) the humidity index declined slightly overall, with the drought growing more intense from the southeast to the northwest, but in general, the difference is not obvious; 4) the coefficient of correlation between humidity index respectively with temperature and precipitation were -0.465 and 0.950.