期刊文献+

Impact of Planetary Wave Reflection on Tropospheric Blocking over the Urals–Siberia Region in January 2008 被引量:4

Impact of Planetary Wave Reflection on Tropospheric Blocking over the Urals–Siberia Region in January 2008
下载PDF
导出
摘要 Planetary wave reflection from the stratosphere played a significant role in changing the tropospheric circulation pattern over Eurasia in mid-January 2008. We studied the 2008 event and compared with composite analysis (winters of 2002/2003, 200412005, 200612007, 200712008, 201012011 and 2011/2012), when the downward coupling was stronger, by employing time-lagged singular value decomposition analysis on the geopotential height field. In the Northern Hemisphere, the geopo- tential fields were decomposed into zonal mean and wave components to compare the relative covariance patterns. It was found that the wavenumber 1 (WN1) component was dominant compared with the wavenumber 2 (WN2) component and zonal mean process. For the WNI field, the covariance was much higher (lower) for the negative (positive) lag, with a prominent peak around +15 days when the leading stratosphere coupled strongly with the troposphere. It contributed to the downward coupling due to reflection, when the stratosphere exhibited a partially reflective background state. We also analyzed the evolution of the WNI anomaly and heat flux anomaly, both in the troposphere and stratosphere, during January- March 2008. The amplitude of the tropospheric WN 1 pattern reached a maximum and was consistent with a downward wave coupling event influenced by the stratospheric WN1 anomaly at 10 hPa. This was consistent with the reflection of the WN1 component over Eurasia, which triggered an anomalous blocking high in the Urals-Siberia region. We further clarified the impact of reflection on the tropospheric WNI field and hence the tropospheric circulation pattern by changing the propagation direction during and after the event. Planetary wave reflection from the stratosphere played a significant role in changing the tropospheric circulation pattern over Eurasia in mid-January 2008. We studied the 2008 event and compared with composite analysis (winters of 2002/2003, 200412005, 200612007, 200712008, 201012011 and 2011/2012), when the downward coupling was stronger, by employing time-lagged singular value decomposition analysis on the geopotential height field. In the Northern Hemisphere, the geopo- tential fields were decomposed into zonal mean and wave components to compare the relative covariance patterns. It was found that the wavenumber 1 (WN1) component was dominant compared with the wavenumber 2 (WN2) component and zonal mean process. For the WNI field, the covariance was much higher (lower) for the negative (positive) lag, with a prominent peak around +15 days when the leading stratosphere coupled strongly with the troposphere. It contributed to the downward coupling due to reflection, when the stratosphere exhibited a partially reflective background state. We also analyzed the evolution of the WNI anomaly and heat flux anomaly, both in the troposphere and stratosphere, during January- March 2008. The amplitude of the tropospheric WN 1 pattern reached a maximum and was consistent with a downward wave coupling event influenced by the stratospheric WN1 anomaly at 10 hPa. This was consistent with the reflection of the WN1 component over Eurasia, which triggered an anomalous blocking high in the Urals-Siberia region. We further clarified the impact of reflection on the tropospheric WNI field and hence the tropospheric circulation pattern by changing the propagation direction during and after the event.
出处 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第3期309-318,共10页 大气科学进展(英文版)
基金 supported jointly by the National Natural Science Foundation of China(Grant Nos.41350110331 and 41450110431) the China Postdoctoral Science Foundation(Grant No.2013M541010)
关键词 planetary wave reflection singular value decomposition (SVD) Eliassen-Palm (EP) flux BLOCKING CIRCULATION planetary wave reflection, singular value decomposition (SVD), Eliassen-Palm (EP) flux, blocking, circulation
  • 相关文献

参考文献1

二级参考文献6

共引文献8

同被引文献80

引证文献4

二级引证文献13

相关作者

内容加载中请稍等...

相关机构

内容加载中请稍等...

相关主题

内容加载中请稍等...

浏览历史

内容加载中请稍等...
;
使用帮助 返回顶部