DOI: 10.1007/s00382-015-2668-0
Scopus记录号: 2-s2.0-84959120089
论文题名: Why the South Pacific Convergence Zone is diagonal
作者: van der Wiel K. ; Matthews A.J. ; Joshi M.M. ; Stevens D.P.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 46, 期: 2017-05-06 起始页码: 1683
结束页码: 1698
语种: 英语
英文关键词: Asymmetry
; IGCM4
; Moisture transport
; Rossby waves
; SPCZ
; SST
英文摘要: During austral summer, the majority of precipitation over the Pacific Ocean is concentrated in the South Pacific Convergence Zone (SPCZ). The surface boundary conditions required to support the diagonally (northwest–southeast) oriented SPCZ are determined through a series of experiments with an atmospheric general circulation model. Continental configuration and orography do not have a significant influence on SPCZ orientation and strength. The key necessary boundary condition is the zonally asymmetric component of the sea surface temperature (SST) distribution. This leads to a strong subtropical anticyclone over the southeast Pacific that, on its western flank, transports warm moist air from the equator into the SPCZ region. This moisture then intensifies (diagonal) bands of convection that are initiated by regions of ascent and reduced static stability ahead of the cyclonic vorticity in Rossby waves that are refracted toward the westerly duct over the equatorial Pacific. The climatological SPCZ is comprised of the superposition of these diagonal bands of convection. When the zonally asymmetric SST component is reduced or removed, the subtropical anticyclone and its associated moisture source is weakened. Despite the presence of Rossby waves, significant moist convection is no longer triggered; the SPCZ disappears. The diagonal SPCZ is robust to large changes (up to ±6 °C) in absolute SST (i.e. where the SST asymmetry is preserved). Extreme cooling (change <−6 °C) results in a weaker and more zonal SPCZ, due to decreasing atmospheric temperature, moisture content and convective available potential energy. © 2015, Springer-Verlag Berlin Heidelberg. 资助项目: NOAA, National Oceanic and Atmospheric Administration
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53807
Appears in Collections: 过去全球变化的重建
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作者单位: Centre for Ocean and Atmospheric Sciences, University of East Anglia, Norwich, United Kingdom; School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom; School of Mathematics, University of East Anglia, Norwich, United Kingdom; Climatic Research Unit, University of East Anglia, Norwich, United Kingdom
Recommended Citation:
van der Wiel K.,Matthews A.J.,Joshi M.M.,et al. Why the South Pacific Convergence Zone is diagonal[J]. Climate Dynamics,2016-01-01,46(2017-05-06)