| 两次不同ENSO背景下云南冬季极端冷事件的成因分析 |
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| 引用本文： | 万云霞,晏红明,金燕,任菊章,黎文懋.两次不同ENSO背景下云南冬季极端冷事件的成因分析[J].大气科学学报,2023,46(4):575-586. |
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| 作者姓名： | 万云霞 晏红明 金燕 任菊章 黎文懋 |
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| 作者单位： | 云南省气象服务中心, 云南 昆明 650034;云南省气候中心, 云南 昆明 650034;云南省气象科学研究所, 云南 昆明 650034 |
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| 基金项目： | 国家自然科学基金资助项目(U1902209) |
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| 摘 要： | 2008年初和2016年初分别经历了一次中等强度以上的La Niña和El Niño事件,在不同的厄尔尼诺-南方涛动(El Niño/Southern Oscillation,ENSO)背景下,云南均发生了低温雨雪冰冻天气。本文利用大气环流、海表温度、云南124个观测站逐月温度等资料,通过多种统计方法探讨了不同ENSO背景下极端冷事件发生的原因。结果表明:1)2008年初和2016年初云南冬季极端冷事件在2月表现更明显。2)不同ENSO背景下,2月大气环流和云南气温变化差异较大。La Niña(El Niño)年西伯利亚高压加强(减弱),位势高度场北(西)高南(东)低,西太平洋副高偏弱(强),菲律宾异常(反)气旋西北侧异常北(南)风加强,东亚冬季风偏强(弱),云南东部气温偏低(高)。3)2008年和2016年的东北太平洋大气环流异常对赤道中东太平洋海温异常均有响应,同时2008年赤道中东太平洋冷海温作用激发的菲律宾气旋西部偏北气流对东亚冬季风的加强和向南活动有重要影响,而2016年赤道中东太平洋暖海温对菲律宾地区环流变化的影响并不显著。4)北极涛动(Arctic Oscillation,AO)和北极海冰变化对2008年2月和2016年2月西伯利亚高压的加强的影响表现出一定的差异特征,2月AO负位相变化对2008年西伯利亚高压的加强影响较大,而2月北极海冰偏少对2016年西伯利亚高压加强的影响显著。
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| 关 键 词： | El Niñ o事件 La Niñ a事件 云南极端冷事件 北极涛动 北极海冰 |
| 收稿时间： | 2022/6/14 0:00:00 |
| 修稿时间： | 2022/10/16 0:00:00 |
Causes of two extremely cold events in Yunnan during different ENSO events |
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| WAN Yunxi,YAN Hongming,JIN Yan,REN Juzhang,LI Wenmao.Causes of two extremely cold events in Yunnan during different ENSO events[J].大气科学学报,2023,46(4):575-586. |
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| Authors: | WAN Yunxi YAN Hongming JIN Yan REN Juzhang LI Wenmao |
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| Institution: | Yunnan Meteorological Service Center, Kunming 650034, China;Yunnan Climate Center, Kunming 650034, China;Yunnan Institute of Meteorological Science, Kunming 650034, China |
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| Abstract: | Two moderate La Niña and El Niño events occurred in early 2008 and early 2016,respectively.During these two distinct El Niño/Southern Oscillation (ENSO) events,Yunnan experienced low temperatures and snowstorms.This study investigates the causes of these two extreme cold events during different ENSO events using statistical methods based on atmospheric circulation data,sea surface temperature (SST),and monthly temperature records from 124 observation stations in Yunnan.The findings are as follows:1) The extremely cold events in Yunnan were more pronounced in February for both 2008 and 2016.2) During the two different ENSO events in February,the variations in atmospheric circulation and temperature exhibited notable differences.In La Niña (El Niño) years,the Siberian high strengthened (weakened),with high geopotential height in the north (west) and low geopotential height in the south (east).The western Pacific subtropical high weakened (strengthened),and anomalous northerly (southerly) winds intensified on the northwest side of the Philippine anomalous cyclone (anticyclone).Additionally,the East Asian winter Monsoon was strong (weak),resulting in low (high) temperatures in the eastern region of Yunnan.3) The atmospheric circulation over the northeast Pacific responded to SST anomalies in the central and eastern equatorial Pacific in 2008 and 2016.Furthermore,the northerly current in the west of the Philippine cyclone triggered by the cold SST in the central and east of the equatorial Middle East Pacific significantly impacted the strengthening and southward activity of the East Asian winter monsoon in 2008,while the warm SST had no significant impact on the atmospheric circulation over the Philippines region in 2006.4) The effects of the Arctic Oscillation (AO) and Arctic Sea ice on the strengthening of the Siberian high in February 2008 and 2016 exhibited different characteristics.The positive phase of AO had a greater impact on the strengthening of the Siberian high in February 2008,whereas the reduction in Arctic Sea ice had a significant impact on the strengthening of the Siberian high in February 2016. |
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| Keywords: | El Niñ o events La Niñ a events extremely cold events in Yunnan Arctic Oscillation sea ice in Arctic |
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