摘要
拉尼娜事件与我国气候密切相关,近年来重庆地区频繁出现的高温干旱与拉尼娜事件的关联值得深入研究。研究重庆高温干旱的特征及其对拉尼娜事件的响应,以期对该地区的高温干旱预测和预警提供科学依据。基于1981—2022年气象干旱综合指数MCI(Meteorological Drought Composite Index)、高温日数、NCEP/NCAR(National Centers for Environmental Prediction/National Center for Atmo⁃spheric Research)再分析环流场和Hadley海温数据,分析重庆夏季高温和气象干旱的时空分布特征,探寻拉尼娜事件对高温干旱的影响及其环流异常特征。结果表明:夏季是重庆干旱发生频率最高且持续时间最长的季节,高温干旱主要集中在东北部及长江沿线地区。高温与干旱之间存在相互促进的关系,持续高温促进重度干旱的形成,而长期干旱也可能导致极端高温的发生。赤道中东太平洋海温在冬、春季处于拉尼娜状态,对重庆夏季的高温和干旱有显著影响。弱拉尼娜事件倾向于引发高温,而中等强度拉尼娜事件更易导致干旱。中部型和东部型拉尼娜事件均对重庆夏季高温和干旱产生显著影响。拉尼娜事件影响下的南亚高压偏大、偏强、偏北,西太平洋副热带高压随之产生的偏大、偏强、偏北,以及高空急流位置偏北,是导致重庆夏季高温和干旱发展的重要环流因素。夏季重庆地区对流层中下层主要受偏弱的西南风控制,结合欧亚中高纬环流呈“两脊一槽”格局,形成不利于冷空气南下的气候环境,从而导致包括重庆地区在内的四川盆地长期受下沉气流控制,是重庆地区高温和干旱频发的主要原因。
The La Niña event was so related to China's climate that it had a significant impact on the high temperature and drought in Chongqing.In recent years,the high temperature and drought in Chongqing had repeatedly reached new highs.Studying the characteris⁃tics of high temperature and drought in the region and its response to the La Niña event can improve the prediction and early warning capabilities of high temperature and drought in Chongqing.Based on the MCI(meteorological drought composite index),high tempera⁃ture days,NCEP/NCAR(National Centers for Environmental Prediction/National Center for Atmospheric Research)reanalysis of circu⁃lation field data and Hadley SST(sea surface temperature)data from 1981 to 2022,the temporal and spatial distribution characteristics of meteorological drought stations and high temperature days during summer in Chongqing were analyzed.Furthermore,the impact of La Niña event on summer drought stations and high temperature days in Chongqing and its circulation anomaly characteristics were ex⁃plored.The results showed that summer was the season with the highest frequency and longest duration of drought in Chongqing.Drought and high temperatures were mainly distributed in the northeast and along the Yangtze River.High temperature and meteoro⁃logical drought promoted so each other that prolonged high temperature was conducive to the development of severe drought,while pro⁃longed drought was also conducive to the occurrence of extreme maximum temperatures.In the early winter and spring,the SST in the equatorial middle east Pacific was in La Niña state,which was conducive to the occurrence of high temperature and drought in Chongq⁃ing during summer.The weak La Niña event was conducive to the occurrence of summer high temperatures in Chongqing,while the moderate intensity La Niña event was conducive to the development of drought.Both the central and eastern types of La Niña event were conducive to the occurrence of summer high temperatures and drought in Chongqing.The
作者
何慧根
张驰
吴遥
李永华
杨琴
穆玉娇
HE Huigen;ZHANG Chi;WU Yao;LI Yonghua;YANG Qin;MU Yujiao(CMA Key Open Laboratory of Transforming Climate Resources to Economy,Chongqing Climate Center,Chongqing 401147,China;Civil Aviation Flight University of China,Chengdu 611430,China)
出处
《干旱气象》
2023年第6期873-883,共11页
Journal of Arid Meteorology
基金
中国气象局创新发展专项(CXFZ2022J031)
重庆市气象局业务技术攻关项目(YWJSGG-202125、YWJSGG-202304)
中国气象局复盘总结专项(FPZJ2023-106)共同资助。
关键词
重庆
高温干旱
拉尼娜
环流成因
下沉气流
Chongqing
high temperature and drought
La Niña event
cause of circulation
downdraft
