李刚,马继望,梁湘三. 2020. 2008年1月中国南方低温雨雪期间异常阻塞高压事件的多尺度动力过程分析[J]. 气象学报, (0):-, doi:10.11676/qxxb2020.016
2008年1月中国南方低温雨雪期间异常阻塞高压事件的多尺度动力过程分析
A study of the multiscale dynamical processes underlying the blocking high that causes the January 2008 freezing rain and snow storm in Southern China
投稿时间:2019-06-29  修订日期:2019-08-22
DOI:10.11676/qxxb2020.016
中文关键词:  阻塞高压,多尺度子空间变换,多尺度能量,正则传输,天气尺度强迫
英文关键词:Blocking high, multiscale window transform, multiscale energetics, canonical transfer, synoptic scale forcing
基金项目:
作者单位E-mail
李刚 山东省气象局 yantailigang@126.com 
马继望 山东省气象台 ma@ncoads.org 
梁湘三 南京信息工程大学 san@pacific.harvard.edu 
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中文摘要:
      2008年1月,我国南方发生了罕见的低温雨雪灾害,造成这次灾害的关键系统之一是中高纬度的异常阻塞高压(后文简称阻高)。本文利用一套新的分析工具-多尺度子空间变换(MWT)和重构-分析了这一期间阻高的多尺度特征,发现其源头来自欧洲地区,强度减弱后东移,在乌拉尔山-贝加尔湖地区重新增强并得以维持相当长的时间。一个新的发现是:前人认定的两次阻高过程本质上是同一过程在不同阶段的表现。为探讨上述过程的动力学机制,本文利用基于MWT的局地多尺度能量分析方法以及正则传输理论对其进行了分析,发现此次异常阻高过程源自天气尺度的强迫,具体地说,能量来自由天气尺度向阻塞高压尺度的正压正则传输,而且这种正则传输在阻高环流的东西两侧不对称,西侧在强度上远大于东侧。分析表明,上述非对称的强迫作用由动能的空间输运来平衡,平流将西侧获得的阻高尺度动能向东侧输运,以此来维持阻高环流的整体稳定和均一。上述两种内部的物理过程是高压环流在东移的过程中得以重新增强并长时间维持的机制。
英文摘要:
      In January 2008, an unusual mid-high latitude blocking high pressure system causes a record-breaking freezing rain and snow storm event in Southern China. Using a recently developed functional analysis tool, namely, multiscale window transform (MWT), the system is investigated for an understanding of the underlying mechanism(s). By examining the multiscale patterns as reconstructed, the blocking high is found to originate from the European region; it moves eastward after weakened. The weakened high, however, regains energy over Mt. Ural-Lake Beaikal, and persists henceforth. A new finding is, the previously identified two blocking highs are essentially the two stages of one event. We used the MWT-based localized multiscale energetics analysis and the theory of canonical transfer to investigate the dynamical processes underlying the anomalous event, and found that it is driven by synoptic eddies. Specifically, its energy comes from the barotropic canonical transfer from the synoptic scale window to blocking scale window. The canonical transfer is asymmetric about the blocking high, much stronger in the west than in the east. This asymmetry is balanced through a west-to-east energy transport on the blocking scale window, in order to maintain a quasi-stable and homogeneous pattern. It is these two internal processes that lead to the rejuvenation and stagnation of the blocking high, causing the severe, disastrous weather in Southern China.
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