Journal of Arid Meteorology ›› 2023, Vol. 41 ›› Issue (1): 14-24.DOI: 10.11755/j.issn.1006-7639(2023)-01-0014

• Articles • Previous Articles     Next Articles

Circulation characteristics of drought-flood transition from spring to summer over the east region of Northwest China and its relationship with Atlantic sea surface temperature

ZHANG Wen1,2(), MA Yang1,2, WANG Suyan1,2(), WANG Dai1,2, LI Xin1,2   

  1. 1. Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions, China Meteorological Administration, Yinchuan 750002, China
    2. Ningxia Hui Autonomous Region Climate Center, Yinchuan 750002, China
  • Received:2022-05-17 Revised:2022-08-10 Online:2023-02-28 Published:2023-02-28

西北地区东部春夏季旱涝转换环流特征及其与大西洋海温的关系

张雯1,2(), 马阳1,2, 王素艳1,2(), 王岱1,2, 李欣1,2   

  1. 1.中国气象局旱区特色农业气象灾害监测预警与风险管理重点实验室,宁夏 银川 750002
    2.宁夏回族自治区气候中心,宁夏 银川 750002
  • 通讯作者: 王素艳(1974—),正高级工程师,主要从事气候与气候变化方面的研究。E-mail: nxwsy_cn@sina.com
  • 作者简介:张雯(1990—),女,硕士,工程师,主要从事短期气候预测、气候变化方面的研究。 E-mail: acaimeme@sina.cn
  • 基金资助:
    宁夏自然科学基金项目(2022AAC03674);宁夏青年拔尖人才培养工程项目共同资助

Abstract:

With the global warming, the intensity and frequency of abnormal drought and flood are increasing, to improve the understanding of drought-flood transition events and the ability of precipitation prediction in the east region of Northwest China, the circulation characteristics of drought-to-flood transition over the east region of Northwest China from spring to summer are analyzed by establishing an index based on the observed monthly mean precipitation, sea surface temperature (SST), and NCEP/NCAR reanalysis datasets during 1979-2020, and the possible influence from the Atlantic SST anomalies is also discussed. The results are summarized as follows: In spring of drought-to-flood years, the polar vortex is weaker, the Ural blocking is stronger and deeper, and the east Asian trough is deeper, which result in less precipitation in the east region of Northwest China controlled by dry and cold northwest flow. In summer, the upstream low-pressure system is active, the south Asian high is stronger and the western Pacific subtropical high (WPSH) is stronger and westward. Such circulation anomalous can lead to warm and moisture air supplement, resulting in a sharp transition phenomenon occurring in the east region of Northwest China. While in flood-to-drought years, it presents an opposite feature. From the previous winter to summer, the Atlantic tripole SST anomalies are key factors affecting the difference of precipitation between spring and summer. In spring of drought-to-flood years, the negative phase of the Atlantic tripole SST pattern stimulates a zonal teleconnection wave train, passing through the central and western Europe, Lake Balkhash, and Northeast China to the Sea of Japan, and this circulation is conducive to less precipitation in the study area. With respect to summer, the intensity of the wave train is weakened and shifts westward. Therefore, the intensity and location of the key circulation system in the middle and high latitudes are adjusted comparing with that in spring, causing more precipitation. In flood-to-drought years the opposite occurs.

Key words: the east region of Northwest China, drought-flood transition, the Atlantic SST anomalies, mid-high latitude wave train

摘要:

随着全球变暖,旱涝异常的强度和频率不断增加,为增进对旱涝异常转换事件的认识,提高西北地区东部降水预测水平,利用19792020年我国西北地区东部逐月降水、海表温度(Sea Surface Temperature, SST)数据以及NCEP/NCAR环流再分析资料,通过建立旱涝转换指数,对西北地区东部春、夏季旱涝转换环流特征进行分析,并围绕大西洋SST异常对其可能产生的影响进行探讨。结果表明:西北地区东部旱转涝年,春季极涡偏弱,乌拉尔山阻塞高压偏强,东亚大槽偏深,西北地区东部受西北干冷气流控制,降水易偏少;夏季上游低值系统活跃,南亚高压偏强,西太平洋副热带高压偏强、偏西,西北地区东部受副热带高压和上游低槽系统共同影响,且有暖湿气流,降水易偏多,涝转旱年情况相反。上年冬季至当年夏季,大西洋类“三极子”型的SST异常是造成季节间降水明显差异的关键因子,旱转涝年春季大西洋类“三极子”负位相的SST状态激发出一支纬向型遥相关波列,经欧洲中西部、巴尔喀什湖地区东传至我国东北至日本海一带,此时中高纬环流形势有利于西北地区东部降水偏少;夏季SST异常激发的波列强度减弱、位置西移,中高纬关键环流系统的强度和位置较春季明显调整,转为有利于研究区降水偏多的环流形势,涝转旱年相反。

关键词: 西北地区东部, 旱涝转换, 大西洋SST异常, 中高纬波列

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