| 近60年华北春季干旱特征及其与北大西洋海表温度的关系 |
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| 引用本文： | 臧迪,郑有飞,张顾炜.近60年华北春季干旱特征及其与北大西洋海表温度的关系[J].大气科学学报,2021,44(3):451-460. |
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| 作者姓名： | 臧迪 郑有飞 张顾炜 |
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| 作者单位： | 南京信息工程大学 环境科学与工程学院, 江苏 南京 210044;南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044 |
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| 基金项目： | 国家自然科学基金资助项目（41831174）;国家重点研发计划（2017YFA0603804） |
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| 摘 要： | 利用观测资料统计分析和CAM5.3数值模拟相结合的方法,基于标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index, SPEI),分析了1955—2018年华北地区春季干旱特征,并重点探讨了对北大西洋产生的影响。华北春季干旱的主要空间分布型为全区一致型,近60 a春季华北存在22 a偏旱年和14 a偏涝年。华北春季偏旱年主要大气环流特征是大陆暖高压增强、高空西风急流减弱以及华北位于下沉运动区中。观测分析和数值模拟结果均表明,春季北大西洋海温偏暖容易导致华北地区发生干旱。当春季北大西洋偏暖,其上空高度场被抬升,激发出一条自北大西洋经欧亚大陆至华北地区的"+-+"的波列,其波列中心分别位于北大西洋、欧洲大陆-西亚和西北-华北地区上空,这条波列最终导致了西北-华北上空大陆高压增强,华北位于高压底部,上空高度场抬升,西风急流减弱,引发下沉运动,导致空气绝热增温。同时,西风急流减弱导致西南暖湿气流减弱,水汽不易到达华北地区,不利于降水产生,高温少雨有利于干旱发生;当北大西洋偏冷时,波列中心发生了"翻转",由"+-+"转变为"-+-",此时大陆高压减弱,西风急流增强,不利于干旱发生。
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| 关 键 词： | 华北地区 春季干旱 北大西洋 波列 |
| 收稿时间： | 2020/2/19 0:00:00 |
| 修稿时间： | 2020/5/8 0:00:00 |
Characteristics of spring drought in North China over the past 60 years and its relationship with sea surface temperature in the North Atlantic |
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| ZANG Di,ZHENG Youfei,ZHANG Guwei.Characteristics of spring drought in North China over the past 60 years and its relationship with sea surface temperature in the North Atlantic[J].大气科学学报,2021,44(3):451-460. |
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| Authors: | ZANG Di ZHENG Youfei ZHANG Guwei |
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| Institution: | School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China; Key Laboratory of Meteorological Disaster of Ministry of Education (KLME), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing 210044, China |
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| Abstract: | Based on the standardized precipitation evapotranspiration index (SPEI),this study applied statistical observational analysis and numerical simulations (CAM 5.3),so as to analyze the characteristics of spring drought in North China (NC) from 1955 to 2018,as well as the impacts of the North Atlantic (NA).The results showed that the main spatial distribution pattern of spring drought in NC was uniform throughout the entire region,and,in the past 60 years,there were 22 drought years and 14 flood years.The main atmospheric circulations of the NC spring drought years were the enhanced continental high,weakened upper westerly jet,and downward movement in NC.Aside from these,both observational analysis and numerical simulation results showed that the warm sea surface temperature (SST) in the NA could cause spring drought in NC.The mechanism is as follows:warm SST in NA can lead to a "+-+" wave train such as the "Silk Road Pattern" with its center above the NA,Europe-western Asia and NC;this wave train would then enhance the continental high over NC,which could cause the downward movements;these downward movements are not conducive to precipitation,and will lead to the air undergoing adiabatic heating;in addition,NC lies to the south of the upper anticyclone circulation,which leads to NC being controlled by the northeast airflow,thus signifying that the warm and humid airflow from the Southwest is weakened.In summary,the wave train causes the high temperature and reduced rain in NC,which is conducive to drought.When the SST in the NA grows cold,the center of the wave train would be reversed,which in turn would cause the continental high over NC to weaken. |
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| Keywords: | North China spring drought North Atlantic wave trains |
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