黄河中游流域极端降水与气温的关系

Relationship of Extreme Precipitation and Temperature in Middle Reaches of Yellow River Basin

为研究黄河中游流域极端降水与气温间的关系,采用气温等距法分别提取了不同气温样方内75%、90%、95%、99%分位数下的极端降水阈值,进而分析了极端降水随气温变化的特性,并探究年极端降水事件数量的时空变化规律。结果表明,极端降水强度随气温上升呈峰型形态,峰值出现于16~18℃;在不同格点间,极端降水峰型形态的峰值差异性明显高于其峰值所对应气温的差异性;整体而言,1961~2019年,年极端降水事件数量在较高的气温区间(>16℃)和较低的气温区间(<16℃)内分别呈上升、下降趋势;黄河流域中游年极端降水事件数量在1961~2019年整体呈先下降后上升的趋势;黄河中游流域极端降水事件数量空间分布在不同百分位数间差异较小,整体上呈西多东少的现象;就年际变化趋势而言,极端降水事件数量在北部增多、南部减少。

To study the relationship between extreme precipitation and temperature of the middle reaches of the Yellow River Basin,the equal-temperature distance bin method was applied to extract the extreme precipitation at 75%,90%,95%,and 99%percentile in different temperature bins.The characteristics of extreme precipitation variations with temperature were analyzed,and the temporal and spatial variations of the number of annual extreme precipitation events were investigated.The results show that the extreme precipitation intensity presents a peak-type structure by increasing temperature,with the peak value appearing at 16-18℃.In different grids,the difference in peak value of extreme precipitation intensity was significantly higher than the difference in temperature corresponding to the peak value.Commonly,from 1961 to 2019,the number of annual extreme precipitation events showed an upward trend and a downward trend in the higher temperature range(>16℃)and the lower temperature range(<16℃),respectively.Generally,from 1961 to 2019,the number of annual extreme precipitation events of the middle reaches of the Yellow River Basin showed a downward trend and then presented an upward trend.The spatial distribution of the number of extreme precipitation events is almost the same under different percentiles.Generally,the number of extreme precipitation events in the west is more than that in the east.Regarding inter-annual trends,the number of extreme precipitation events increases in the north while decreasing in the south trend.