DOI: 10.1175/JCLI-D-16-0310.1
Scopus记录号: 2-s2.0-85012302395
论文题名: Impact of tropical SSTs in the North Atlantic and southeastern Pacific on the eastern Pacific ITCZ
作者: Song F. ; Zhang G.J.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2017
卷: 30, 期: 4 起始页码: 1291
结束页码: 1305
语种: 英语
Scopus关键词: Atmospheric structure
; Atmospheric temperature
; Budget control
; Climate models
; Climatology
; Moisture
; Surface waters
; Convergence/divergence
; Coupled models
; Intertropical convergence zone
; Moisture/moisture budgets
; Spring season
; Oceanography
; climate modeling
; climatology
; intertropical convergence zone
; moisture
; precipitation (climatology)
; sea surface temperature
; spring (season)
; thermodynamics
; Atlantic Ocean
; Atlantic Ocean (North)
; Pacific Ocean
; Pacific Ocean (East)
; Pacific Ocean (Southeast)
英文摘要: During boreal spring, observations show a double ITCZ over the eastern Pacific, with the northern ITCZ stronger than the southern ITCZ. However, it is opposite in most climate models. It is also evident that there exists a cold bias in tropical North Atlantic (TNA) sea surface temperature (SST) and a warm bias in southeastern Pacific (SEP) SST. In this study, the influences of TNA and SEP SSTs on the double-ITCZ bias are investigated by prescribing the observed SST in these regions in the NCAR CESM1. Results show that when TNA SST is prescribed, the northern ITCZ is substantially enhanced and the southern ITCZ is moderately reduced, although the SST response in these regions is small. When the SEP SST is prescribed, the southern ITCZ is reduced considerably. When both TNA and SEP SSTs are prescribed, the double-ITCZ bias is reduced by ~68%. Moisture budget analysis suggests that dynamics, mainly the low-level convergence change, determines the above precipitation changes. Based on a mixed layer model, changes in low-level convergence are shown to be determined by surface pressure Ps changes. With prescribed TNA/SEP SSTs, SST gradients change the Ps in the region directly via the Lindzen-Nigam mechanism. The corresponding low-level circulation changes affect the 850-hPa thermodynamic state in a wider region, which in turn not only strengthens the SST-induced Ps change locally but also leads to Ps changes remotely, including the northern ITCZ region. Furthermore, the low-level convergence changes the vertical structure of moist static energy, altering the atmospheric stability and modulating precipitation distribution. © 2017 American Meteorological Society. 资助项目: NSF, 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/49849
Appears in Collections: 气候变化事实与影响
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作者单位: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
Recommended Citation:
Song F.,Zhang G.J.. Impact of tropical SSTs in the North Atlantic and southeastern Pacific on the eastern Pacific ITCZ[J]. Journal of Climate,2017-01-01,30(4)