中国北方干旱多发带极端春夏连旱的主要影响因子特征  

Characteristics of the Main Factors Affecting Prolonged Spring-summer Extreme Drought Events in Northern Drought-prone Belt

作　　者：陆晓娟 李忆平[1] 王劲松[1] LU Xiaojuan;LI Yiping;WANG Jinsong(Institute of Arid Meteorology,China Meteorological Administration,Gansu Key Laboratory of Arid Climatic Change and Reducing Disaster,Key Laboratory of Arid Climatic Change,Lanzhou 730020,Gansu,China)

机构地区：[1]中国气象局兰州干旱气象研究所/甘肃省干旱气候变化与减灾重点实验室/中国气象局干旱气候变化与减灾重点开放实验室,甘肃兰州730020

出　　处：《高原气象》2025年第1期67-82,共16页Plateau Meteorology

基　　金：国家自然科学基金重点项目(42230611);中国气象局兰州干旱气象研究所创新团队项目(GHSCXTD-2020-2)。

摘　　要：在全球变暖背景下,天气气候事件表现出的极端性愈加明显,由此造成的各种气象灾害对社会和经济的危害程度进一步加大。在中国北方干旱多发带(Northern Drought-prone Belt,NDPB),极端干旱事件发生的次数更为频繁、强度更为剧烈、范围更为广阔。本文利用气象干旱综合指数、站点的降水和近地面气温、再分析资料以及海表温度、积雪范围、海冰密集度资料,通过统计分析和合成分析方法揭示了NDPB极端春夏连旱事件的主要影响因子特征。研究表明,主要环流因子表现为:3月自巴芬湾东传的波列,5月从哈德逊湾南部到贝加尔湖以东“正-负-正-负-正-负”的位势高度异常,6月60°N附近东传的波列、丝路波列以及偏东偏弱的西太平洋副热带高压;主要的外强迫因子表现为:拉尼娜向厄尔尼诺的位相转变及印度洋海盆和北大西洋中部偏暖的海温异常,欧亚大陆中高纬和北美大陆40°N-60°N之间明显偏小、青藏高原前期偏大后期偏小的积雪范围异常,以及巴芬湾和戴维斯海峡附近偏少而格陵兰海附近偏多、从巴伦支海到喀拉海呈现“正-负-正”分布的海冰密集度异常。Purposes Methods Extreme weather and climate events have been exhibiting an intensification under global warming.This intensified extremity thus augments the damaging impacts on both society and the economy.In the Northern Drought-prone Belt(NDPB),extreme drought events are becoming more frequent and more intense with a broader distribution.In this study,by using statistical analysis and composite analysis,characteristics of the main factors affecting prolonged spring-summer extreme drought events in NDPB are analyzed based on the meteorological drought composite index,precipitation and near-surface air temperature data observed by meteorological stations,reanalysis dataset,sea surface temperature,snow cover,and the sea ice concentration data.Findings Conclusions Results show that the main circulation factors are as follows:the eastward propagating wave trains from Baffin Bay in March,a“positive-negative-positive-negative-positive-negative”geopotential height anomaly from the south of Hudson Bay to the east of Lake Baikal in May,an eastward wave train near the 60°N latitude,the Silk Road wave train and the eastward,weak Western Pacific Subtropical High in June;the main external forcing factors are listed below:the phase transition from La Niña to El Niño,warmer sea surface temperature over the Indian Ocean basin and the central North Atlantic;the shrinking snow cover in the midto-high latitudes of Eurasia and between 40°N and 60°N of North America,a snow cover reversal from abnormally high to abnormally low over the Qinghai-Tibet Plateau,a“negative-positive”sea ice concentration anomaly with less near Baffin Bay and Davis Strait but more near Greenland Sea,and a“positive-negative-positive”sea ice concentration anomaly from the Barents Sea to the Kara Sea.

关 键 词：极端春夏连旱事件 影响因子 中国北方干旱多发带 

分 类 号：P466[天文地球—大气科学及气象学]