DOI: 10.1175/JCLI-D-14-00622.1
Scopus记录号: 2-s2.0-84944037982
论文题名: Processes Leading to Double Intertropical Convergence Zone Bias in CESM1/CAM5
作者: Wang C.-C. ; Lee W.-L. ; Chen Y.-L. ; Hsu H.-H.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2015
卷: 28, 期: 7 起始页码: 2900
结束页码: 2915
语种: 英语
Scopus关键词: Atmospheric temperature
; Atmospheric thermodynamics
; Boundary layers
; Earth atmosphere
; Surface waters
; Atmosphere-ocean interactions
; Community atmosphere model
; Intertropical convergence zone
; Model evaluation/performance
; North equatorial countercurrent
; Planetary boundary layers
; Sea surface temperature (SST)
; South equatorial currents
; Oceanography
; air-sea interaction
; atmosphere-ocean coupling
; atmospheric modeling
; boundary layer
; intertropical convergence zone
; meridional circulation
; planetary atmosphere
; sea surface temperature
; troposphere
; Pacific Ocean
; Pacific Ocean (East)
英文摘要: The double intertropical convergence zone (ITCZ) bias in the eastern Pacific in the Community Earth System Model version 1 with Community Atmosphere Model version 5 (CESM1/CAM5) is diagnosed. In CAM5 standalone, the northern ITCZ is associated with inertial instability and the southern ITCZ is thermally forced. After air-sea coupling, the processes on both hemispheres are switched because the spatial pattern of sea surface temperature (SST) is changed. Biases occur during boreal spring in both CAM5 and the ocean model. In CAM5 alone, weaker-than-observed equatorial easterly in the tropical eastern South Pacific leads to weaker evaporation and an increase in local SST. The shallow meridional circulation overly converges in the same region in the CAM5 standalone simulation, the planetary boundary layer and middle troposphere are too humid, and the large-scale subsidence is too weak at the middle levels. These biases may result from excessive shallow convection behavior in CAM5. The extra moisture would then fuel stronger convection and a higher precipitation rate in the southeastern Pacific. In the ocean model, the South Equatorial Current is underestimated and the North Equatorial Countercurrent is located too close to the equator, causing a warm SST bias in the southeastern Pacific and a cold bias in the northeastern Pacific. These SST biases feed back to the atmosphere and further influence convection and the surface wind biases in the coupled simulation. When the convection in the tropical northeastern Pacific becomes thermally forced after coupling, the northern ITCZ is diminished due to colder SST, forming the so-called alternating ITCZ bias. © 2015 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50454
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Atmospheric Sciences, Chinese Culture University, Taipei, Taiwan; Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
Recommended Citation:
Wang C.-C.,Lee W.-L.,Chen Y.-L.,et al. Processes Leading to Double Intertropical Convergence Zone Bias in CESM1/CAM5[J]. Journal of Climate,2015-01-01,28(7)