基于两种SPEI序列的淮河流域干湿特征变化

基于FAO56 Penman-Monteith和Hargreaves-Samani两种潜在蒸散发计算方法得到了12个月尺度的标准化降水蒸散指数(SPEI),研究了1960—2016年淮河流域干湿时空变化特征以及两种SPEI序列对相关气象要素的敏感性。结果表明:两种SPEI序列均显示流域呈变湿趋势,温度距平值与SPEI负相关,与潜在蒸散发距平值正相关;空间上,流域西北和东部地区呈显著变湿趋势,中部地区为不显著变干趋势; SPEI去趋势后,流域的干湿变化斜率减小,去趋势过程不改变SPEI的趋势变化分布,只影响流域的干湿变化幅度;气象要素的趋势变化可影响流域干湿变化趋势和干湿等级,淮河流域干湿变化影响因素由强到弱顺序依次为温度、日照时数、风速和相对湿度。

Change of dry-wet characteristics in Huaihe River Basin based on two SPEI sequences

Based on two potential evapotranspiration calculation methods of FAO56 Penman-Monteith and Hargreaves-Samani, standardized precipitation evapotranspiration index(SPEI)at 12-month scale was obtained. The spatial and temporal variations of dry and wet in Huaihe River Basin from 1960 to 2016 and the sensitivity of two SPEI sequences to related meteorological factors were studied. The results show that both SPEI sequences show a trend of wetting. The temperature anomaly is negatively correlated with SPEI and positively correlated with the potential evapotranspiration anomaly. Spatially, the northwest and east of the basin show a significant trend of wetting, while the central region shows a non-significant trend of drying. After the detrend of SPEI, the slope of dry-wet change in the basin decreases, and the detrend process does not change the trend distribution of SPEI, but only affects the range of dry-wet change in the basin. The trend change of meteorological factors can affect the trend and grade of dry-wet change in the basin. The order of influencing factors of dry-wet change in Huaihe River Basin from strong to weak is temperature, sunshine duration, wind speed and relative humidity.