2011/2012年冬季寒潮低频特征及其与500hPa低频系统的耦合关系
投稿时间: 2015-05-27  最后修改时间: 2016-02-16  点此下载全文
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作者单位E-mail
苗青 成都信息工程大学大气科学学院/高原大气与环境四川省重点实验室 mq04209693@163.com 
巩远发 成都信息工程大学大气科学学院/高原大气与环境四川省重点实验室 gyfa@cuit.edu.cn 
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:利用NCEP/DOE的逐日再分析资料和国家气象信息中心的常规观测站温度资料,首先分析了2011/2012年冬季中国低温异常过程中两次典型寒潮过程和全国828个站平均温度低频振荡变化特征,然后分析了温度场低频振荡随位相的演变,最后采用SVD方法研究了北半球中高纬度对流层中层低频环流系统配置对温度低频变化的影响。结果表明:2011/2012年冬季的寒潮和强降温过程是在全国区域平均温度存在较强的10-30d低频振荡的背景下发生的,中国的北方和东南部地区温度的低频振荡较强是导致其降温显著的主要原因之一。SVD分析的第一模态显示,亚洲-西太平洋中低纬度与中高纬度的南北两支低频波列在东亚地区耦合,使我国中东部和东南部地区处于沿偏东路径南下的强冷空气中;第二模态显示,沿着喀拉海-乌拉尔山东侧-我国西部的低频波列引导源地冷空气沿西北路径南下相继影响我国西北和东北地区;这两个模态驱动了强度大、范围广的低频温度由升高向降低变化的振荡,是导致2011/2012年冬季寒潮发生和极端低温事件出现的环流系统。
中文关键词:寒潮  低频振荡  奇异值分解
 
Characteristics of Low-Frequency Oscillations during Cold Wave in the Winter of 2011/2012 and its Coupling with Low-Frequency System at 500hPa
Abstract:Using the daily data of NCEP/DOE reanalysis II and the temperature data established by conventional observation stations of National Meteorological Information Center, cold waves during the extreme event of regional averaged temperature in China in the winter of 2011/2012 and the characteristics of the low-frequency oscillation (LFO) of the mean temperature of 828 stations are analyzed, then the low-frequency temperature field evolve with phases is also analyzed, furthermore the impact of the space configuration of low-frequency circulation system in the mid tropospheric in the extra-tropical of the Northern Hemisphere on temperature changes are studied by using the method of SVD. It is found that: cold waves and strong cooling in the winter of 2011/2012 break out against a background of strong 10-30-day oscillation of the regional averaged temperature in China, strong oscillation of the temperature is one of the main reasons which leads to severe temperature drop in north and southeast China. The first pair of singular vectors in the SVD indicates that the low-frequency wave train in mid-low latitudes is coupled with the one in mid-high latitude in the East Asia region, which makes the middle-east and southeast China locate in the strong cold air spells south along the easterly path. The second pair indicates that low-frequency wave train along Kara - east of the Urals - Northwest China leads strong cold air spells south along the westerly and northerly path then sequentially impact northwest and northeast China. These two models actuate strong LFO of the temperature in broad areas change from increase to decrease, and they are the circulation system responsible for initializing cold waves break out and the extreme low temperature event of China in the winter of 2011/2012.
keywords:cold wave, low-frequency circulation oscillation (LFO), singular value decomposition(SVD)
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