陕西暖季降水的日变化特征及南北差异  

Diurnal variation characteristics and north-south differences of precipitation in warm season in Shaanxi Province

作　　者：张宏芳 李建科 潘留杰[2] 卢珊 ZHANG Hong-fang;LI Jian-ke;PAN Liu-jie;LU Shan(Shaanxi Meteorological Service Centre,Xi'an 710014,Shaanxi,China;Shaanxi Meteorological Observatory,Xi'an 710014,Shaanxi,China)

机构地区：[1]陕西省气象服务中心,陕西西安710014 [2]陕西省气象台,陕西西安710014

出　　处：《干旱区地理》2020年第4期889-898,共10页Arid Land Geography

基　　金：陕西省气象局重点科研项目(2016Z-1);陕西省自然科学基金项目(2019JM-088)资助。

摘　　要：利用2008—2015年CMORPH卫星与自动观测站的逐时降水量融合产品,分析了陕西地区5-10月降水量、降水频次、降水强度的日变化特征,以及陕西南北降水日变化上的差异。结果表明:(1)降水量和降水频次从南向北明显递减,地形作用下的纬向变化是陕西地区降水最重要的特征,但降水强度呈现出南北高、中间低的分布特征,两个高值中心分别位于陕南南部和陕北的东北部,EOF分析表明陕西南部夜雨特征明显。(2)陕西南部降水量和降水频次、降水强度日变化特征一致,均以夜晚至次日清晨为高值区,而在中午前后达到最低值。陕西北部降水量、降水频次峰值则主要出现在上午,降水强度峰值出现在傍晚。区域对比分析表明,陕西南部降水量日变化主要来自于降水强度的贡献,而陕西北部日变化以降水频次的贡献为主。(3)陕西降水的南北分界线特征明显,34°N以南地区降水日变化明显且降水主要集中在夜间。34〜37°N之间的中部地区降水日变化较弱,37°N以北地区降水的日变化特征和陕西南部相反。(4)除榆林、渭南和商洛东部地区外,其他大部分地方白天的降水量都明显低于夜间的降水量,特别是陕南秦巴山区夜间降水量超过白天的一倍以上。Using the combination of data on hourly rainfall from automatic stations and Climate Prediction Center morphing method satellite data from 2008 to 2015,the diurnal variations and differences between the amount of precipitation as well as the frequency and intensity of precipitation in southern and northern Shaanxi Province,China from May to October were studied.Results show as follows:(1)From south to north,both rainfall frequency and amount decreased,with the zonal change under the topography being the most important feature.However,statistics show that precipitation intensity is higher in southwestern and northern Shaanxi and lower in central Shaanxi.The empirical orthogonal function analysis revealed that precipitation in southwestern Shaanxi showed clear night rain characteristics.(2)The diurnal variations of precipitation intensity and frequency were similar to the amount of precipitation amount southern Shaanxi.Both regions display high values from night to early morning and the lowest value around noon.The peak in precipitation amount and precipitation frequency in northern Shaanxi was primarily in the morning,while the peak in precipitation intensity appeared in the late afternoon.Diurnal variations in rainfall amount mainly came from precipitation intensity in southern Shaanxi,while diurnal variations in the north resulted from precipitation frequency.(3)Precipitation in Shaanxi varies greatly depending on what side of the north-south boundary line it falls.Precipitation south of 34°N displays obvious diurnal variation characteristics,and the precipitation is predominantly concentrated at night.There is little variation for precipitation in the central region between 34°N and 37°N,and the diurnal variation of precipitation north of the 37°N is opposite of that in southwestern Shaanxi.(4)Excluding Yulin,eastern Weinan,and Shangluo,the daytime precipitation is higher than nighttime precipitation.Precipitation in the rest of Shaanxi was significantly lower than that in the nighttime,especially in the Qi

关 键 词：陕西 暖季降水 日变化 南北差异 

分 类 号：P426.6[天文地球—大气科学及气象学]