1960~2014年淮河流域极端气温和降水时空变化特征

基于淮河流域33个气象站点1960~2014年逐日气温和降水数据,利用Mann-Kendall检验和克里金插值法分析了极端气温、降水指数的时空变化规律。结果表明：① 近55 a来,冷极值呈显著下降趋势,暖极值表现为波动上升趋势;日较差（DTR）呈显著下降趋势,这与最低气温的增加幅度比最高气温大有关;② 总降水量（PRCPTOT）和强降水日数（R10,R20）表现为缓慢下降趋势,1 d最大降水量（RX1day）、连续5 d最大降水（RX5day）以及降水强度（SDII）呈缓慢上升趋势,但变化趋势均不显著;③ 空间变化上来看,霜冻日数（FD0）、冷夜日数（TN10p）、热夜日数（TR20）和暖夜日数（TN90p）在流域大部分地区变化趋势显著,而降水极值在全流域未表现出一致上升或下降趋势,且变化趋势在全流域均不显著;④ 基于流域当前气象站点数据,极端气温、降水指数变化趋势未表现出高程相依性;⑤ 流域大部分极端气温、降水指数变化趋势介于中国南北方流域之间,表现出一定的南北过渡带特色。

Spatial and Temporal Patterns of Temperature and Precipitation Extremes in the Huaihe River Basin,China in 1960-2014

The frequency of extreme climatic events is increasing under the background of climate change, which leads to a significant impact on production and livelihood. Temporal and spatial distribution characteristics of extreme temperature and precipitation indices had been analyzed using Mann-Kendall test and Kriging interpolation, and the relationships between trend magnitudes of climate extremes and elevations were also discussed based on daily temperature and precipitation data from 33 meteorological stations over the Huaihe River Basin from 1960 to 2014. The results showed that: 1) the cold indices (FD0, ID0, TN10p, TX10p and CSDI) showed significantly decreasing trends; FD0 and TN10p decreased by -4.14 and -1.76 days per decade respectively. The warm indices (TN90p, TX90p, SU25, TR20 and WSDI) exhibited increasing trends; TN90p, TR20 and SU25 increased significantly by 3.01, 1.99 and 3.18 days per decade, respectively. Diurnal temperature range (DTR) showed a significant downward trend because of the minimum temperature increases larger than the maximum temperature. 2) No significant changes for extreme precipitation indices were observed over the past 55 years. PRCPTOT, R10 and R20 showed a slow downward trend, while RX1day, RX5day, as well as the SDII showed a slowly rising trend. 3) From the spatial distribution characteristics of temperature indices, FD0, TN10p, TR20 and TN90p showed significant variations over the most area of the basin; FD0 and TN10p decreased from the center region to the northeastern and southwestern region of the basin; TR20 and TN90p showed the largest increasing rate in the center part of the basin. Considering the extreme precipitation indices, no indices exhibited significant changes over the whole basin. 4) No significant relationships were observed between temperature, precipitation extremes and elevation based on the data captured from current meteorological stations. This indicated that the elevation dependency is deficiency in the Huaihe River Basin, China. 5) The variation trends of extreme temperature and precipitation indices in the Huaihe River Basin are approximately between the Yellow River Valley and the Pearl River, which showed the characteristics of the North-South transition zone. This study is of great significance to the sustainable development of water resources in the Huaihe River Basin, the construction of the South-to-North Water Transfer Project and the disaster prevention and reduction.