DOI: 10.1175/JCLI-D-12-00720.1
Scopus记录号: 2-s2.0-84892450411
论文题名: Warm conveyor belts in the ERA-Interim Dataset (1979-2010). Part I: Climatology and potential vorticity evolution
作者: Madonna E. ; Wernli H. ; Joos H. ; Martius O.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2014
卷: 27, 期: 1 起始页码: 3
结束页码: 26
语种: 英语
Scopus关键词: Absolute vorticity
; Ecmwf re-analysis
; Extratropical cyclones
; Global climatology
; Ice water content
; Potential temperature
; Potential vorticity
; Warm conveyor belts
; Belt conveyors
; Climatology
; Storms
; Trajectories
; Troposphere
; Vorticity
; atmospheric dynamics
; climatology
; cyclone
; extratropical environment
; potential vorticity
; troposphere
英文摘要: A global climatology of warm conveyor belts (WCBs) is presented for the years 1979-2010, based on trajectories calculated with Interim ECMWF Re-Analysis (ERA-Interim) data. WCB trajectories are identified as strongly ascending air parcels (600 hPa in 2 days) near extratropical cyclones. Corroborating earlier studies, WCBs are more frequent during winter than summer and they ascend preferentially in the western ocean basins between 25° and 50° latitude. Before ascending, WCB trajectories typically approach from the subtropics in summer and from more midlatitude regions in winter. Considering humidity, cloud water, and potential temperature along WCBs confirms that they experience strong condensation and integrated latent heating during the ascent (typically >20 K). Liquid and ice water contents along WCBs peak at about 700 and 550 hPa, respectively. The mean potential vorticity (PV) evolution shows typical tropospheric values near 900 hPa, followed by an increase to almost 1 potential vorticity unit (PVU) at 700 hPa, and a decrease to less than 0.5 PVU at 300 hPa. These low PV values in the upper troposphere constitute significant negative anomalies with amplitudes of 1-3 PVU, which can strongly influence the downstream flow. Considering the low-level diabatic PV production, (i) WCBs starting at low latitudes (<40°) are unlikely to attain high PV (due to weak planetary vorticity) although they exhibit the strongest latent heating, and (ii) for those ascending at higher latitudes, a strong vertical heating gradient and high absolute vorticity are both important. This study therefore provides climatological insight into the cloud diabatic formation of significant positive and negative PV anomalies in the extratropical lower and upper troposphere, respectively. © 2014 American Meteorological Society. 资助项目: SNSF, Swiss National Science Foundation
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/51228
Appears in Collections: 气候变化事实与影响
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作者单位: Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland; Oeschger Centre for Climate Change Research, Institute of Geography, University of Bern, Bern, Switzerland
Recommended Citation:
Madonna E.,Wernli H.,Joos H.,et al. Warm conveyor belts in the ERA-Interim Dataset (1979-2010). Part I: Climatology and potential vorticity evolution[J]. Journal of Climate,2014-01-01,27(1)