1970-2012年华北平原大气可降水量时空变化及其影响因素

Spatiotemporal Variation of Precipitable Water and Its Influencing Factors in the North China Plain During 1970-2012

基于1970-2012年华北平原探空站和地面站气象资料,分析了大气可降水量的时空变化特征及其影响因素.结果表明:(1)1970-2012年,华北平原年均大气可降水量呈不显著下降趋势,速率为-0.10mm/10a.其中,秋季大气可降水量减少速率最高,为-0.18mm/10a.在空间上,华北平原东南部年均大气可降水量降低速率明显大于西北部.(2)近40多年来,华北平原年均降水效率基本稳定,速率为-0.01%/10a.(3)在年和季节尺度上,华北平原大气可降水量变化与降水量仅在冬季相关性不显著.在空间上,仅华北平原南部年均大气可降水量与降水量呈显著正相关性;而降水效率与降水量在各尺度上均呈极显著相关性.(4)北半球极涡面积和亚洲区极涡强度分别对春季和夏季大气可降水量的变化影响较大.而秋、冬季,大气可降水量与西伯利亚高压和亚洲经向环流关系密切.

Based on meteorological data of radiosonde stations and ground stations in North China Plain from 1970 to 2012,a variety of statistical methods were used to analyzing the temporal and spatial variation characteristics of atmospheric precipitable water and its influencing factors.The results show that:(1)From 1970 to 2012,the average annual precipitable water of the North China Plain showed no significant downward trend with a rate of-0.10mm/10a.Among them,the rate of decrease in precipitable water in autumn is the highest,which is-0.18 mm/10a.In space,the annual mean precipitable water in southeastern China decreased significantly more than that of the northwest.(2)In the past 40 years,the average precipitation efficiency in the North China Plain has been basically stable with a rate of-0.01%/10a.(3)On the annual and seasonal scales,the correlation between the precipitable water change of the North China Plain and precipitation is only insignificant in winter.In spatiality,only the average annual water vapor content and precipitation in southern North China Plain showed a significant positive correlation.Precipitation efficiency and precipitation are significantly correlated at all scales.(4)The polar vortex area in the Northern Hemisphere and the polar vortex intensity in the Asian region have great effects on the changes of the precipitable water in spring and summer,respectively.In the autumn and winter,the precipitable water is closely related to the Siberian high and the meridional circulation in Asia.