Intraseasonal evolution characteristics of stratosphere-troposphere coupling in association with Arctic sea ice changes and Northern Hemisphere tropopause variability
학위논문(박사) -- 서울대학교대학원 : 자연과학대학 지구환경과학부, 2021.8. 김진주. Variations in stratospheric polar vortex and associated stratosphere-troposphere interaction during boreal winter play an important role in the subseasonal prediction of tropospheric weather. In order to better understand stratosphere-troposphere i...
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| Other Authors: | , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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서울대학교 대학원
2021
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| Online Access: | https://hdl.handle.net/10371/177847 https://dcollection.snu.ac.kr/common/orgView/000000167756 |
| Summary: | 학위논문(박사) -- 서울대학교대학원 : 자연과학대학 지구환경과학부, 2021.8. 김진주. Variations in stratospheric polar vortex and associated stratosphere-troposphere interaction during boreal winter play an important role in the subseasonal prediction of tropospheric weather. In order to better understand stratosphere-troposphere interaction, this study scrutinizes intraseasonal evolutionary characteristics of stratospheric polar vortex fluctuations in terms of two different physical variables: sea ice and tropopause. The leading two modes of winter Arctic sea ice cover variability and their linkage to stratospheric polar vortex variations are analyzed. The first mode represents an accelerating trend of Arctic sea ice decline associated with Arctic amplification, particularly in the Barents and Kara Seas. The second mode is associated with decadal-scale phase shifts of dipole sea ice anomalies in the North Atlantic caused by NAO circulation. The first two modes of sea ice variability represent respectively a forced climate change and internal variability. Sea ice reduction in the Barents and Kara Seas for the first mode is linked to a stratospheric vortex weakening during mid January–late February. The second mode with the dipole structure of positive sea ice anomalies in the Barents and Greenland Seas and negative anomalies in the Hudson Bay and Labrador Sea is related to a stratospheric vortex weakening during December–early February. The spatial evolutionary structure of anomalous polar vortex also exhibits differences between the two modes. When stratospheric anomalies are fully developed, stratospheric vortex is shifted to Eurasia in the first mode and to Europe in the second mode. These two sea ice modes with different low-frequency variations partly contribute to a long-term mean change in subseasonal evolution of stratospheric polar vortex. To identify general evolutionary characteristics in stratosphere-troposphere coupling, the leading modes of Northern Hemisphere tropopause variability for November–April and the associated ... |
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