文章摘要
朱伟军1,李天宇1,2.冬季赤道中东太平洋海温异常对北半球两大洋风暴轴协同变化的可能影响[J].海洋气象学报,2017,37(3):15-26
冬季赤道中东太平洋海温异常对北半球两大洋风暴轴协同变化的可能影响
The possible influence of equatorial central and eastern Pacific SSTA on the concurrent variations of the northern Atlantic and Pacific storm tracks during boreal winter
投稿时间:2017-06-30  修订日期:2017-07-30
DOI:10.19513/j.cnki.issn2096-3599.2017.03.003
中文关键词: 风暴轴  协同变化  ENSO  海气耦合系统
英文关键词: storm track  concurrent variation  ENSO  atmosphere-ocean coupled system
基金项目:国家自然科学基金项目(41575070,41075070);公益性行业(气象)科研专项(GYHY201306028);江苏高校优势学科建设工程(PAPD)
作者单位
朱伟军1,李天宇1,2 1. 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心 2. 吉林省气候中心 
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中文摘要:
   利用NCEP/NCAR(National Centers for Environmental Prediction/National Center for Atmospheric Research)和NOAA(National Oceanic and Atmospheric Administration)提供的再分析资料和CPC(National Climate Prediction Center)提供的Nino3.4指数,研究了与赤道中东太平洋海温异常相对应的ENSO(El Nio-Southern Oscillation)不同位相对同期北半球海气耦合关系及两大洋风暴轴协同关系的影响,具体结论如下:1)赤道中东太平洋海温异常与冬季北半球两大洋风暴轴协同变化关系密切,具体表现为海温正异常时对应北太平洋风暴轴和北大西洋风暴轴同时增强,且大西洋风暴轴整体和太平洋风暴轴东部位置南压,海温负异常时则相反。2)海温正异常(El Nio)年时,对流层中层极涡向北太平洋地区伸展,西北太平洋副热带高压增强西移,东亚大槽减弱,高度场异常对应WP(Western Pacific pattern)、EA(Eastern Atlantic pattern)型遥相关的负位相和PNA(Pacific-North American pattern)型遥相关正位相,对流层低层加拿大高压增强,阿留申低压强度增强并向东南方向移动,东亚急流增强东伸,北美急流强度增强,欧亚大陆50°N附近西风增强,经向环流减弱,北半球的斜压异常分布有利于北太平洋东部风暴轴南侧以及中西部风暴轴的有效位能向扰动动能转换,使得风暴轴增强东部南压,北大西洋风暴轴南部斜压增强,使得风暴轴整体偏南,中、西部强度增强。海温负异常(La Nia)年时,海温和环流异常在两大洋基本与El Nio年相反,对应两大洋风暴轴强度同时减弱,同时北大西洋风暴轴整体和北太平洋风暴轴东部北抬。3)海温正异常(El Nio)年时,北美大陆为北暖南冷的异常分布,60°N以南的东亚地区除我国西南外基本为温度异常升高。海温负异常(La Nia)年时,由于高度场和风场异常在欧亚大陆和北美大陆上的异常分布与El Nio年时并不是完全相反,使得温度场异常主要表现在北美南部和东亚北部异常升高。
英文摘要:
   Base on the reanalysis data of NCEP/NCAR and NOAA, index of Nino3.4 from CPC,influences of different ENSO phases corresponding to SST(sea surface temperature) anomalies in the equatorial middle-eastern Pacific on the coupled pattern of atmosphere-ocean system and the concurrent variations of northern Atlantic and Pacific storm tracks are investigated. The results are summarized as follows:1) The equatorial middle-eastern Pacific SST anomalies are closely related to the concurrent variations between the two storm tracks in boreal winter. When SST anomaly is in positive phase,the two storm tracks are intensified with the whole Atlantic storm track and eastern part of Pacific storm track shift southward. Meanwhile, concurrent variations of the two storm tracks are opposite as SST anomaly is in negative phase.2) When SST anomaly is in positive phase (El Nio), in the middle troposphere, the polar vortex extends toward the northern Pacific, the north-west pacific subtropical high is intensified and moves westward, the East Asian trough is weakened, and the geopotential height anomalies is characterized by the negative phase of WP and EA teleconnection and positive phase of PNA teleconnection. In the low-troposphere, the Canada high is intensified, the Aleutian low is intensified and shifts southeastward, the Jet in East Asia is intensified and extends eastward, the Jet in North America is intensified, and the westerly near 50°N over Eurasia is intensified with weakened meridional circulation. The baroclinic energy anomalies in the Northern Hemisphere enhance the conversion from available potential energy to eddy kinetic energy, resulting in intensified Pacific storm track and the southward shift of eastern storm track. The increase of baroclinic energy to the south of the Atlantic storm track results in southward shift of the whole Atlantic storm track and an intensification in its middle-western parts. When SST anomaly is in negative phase (La Nia), anomalies of SST and circulation are opposite to variations of storm tracks in positive phase.3) When SST anomaly is in positive phase (El Nio), it was warmer in the north and colder in the south over the North American continent in the low-tropospheric temperature field. Temperature anomalously increase over East Asia in area south of 60°N except southwest China. When SST anomaly is in its negative phase (La Nia), the abnormal temperature increase is mainly in the south of North America and north of East Asia, because anomalies of geopotential height and wind in Eurasia and North America are not exactly the opposite to those in El Nio phase.
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