DOI: 10.1007/s00382-017-3650-9
Scopus记录号: 2-s2.0-85017127298
论文题名: Identifying causes of Western Pacific ITCZ drift in ECMWF System 4 hindcasts
作者: Shonk J.K.P. ; Guilyardi E. ; Toniazzo T. ; Woolnough S.J. ; Stockdale T.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2018
卷: 50, 期: 2018-03-04 起始页码: 939
结束页码: 954
语种: 英语
英文关键词: ITCZ
; Model drift
; Seasonal forecasting
; Western Pacific
Scopus关键词: atmospheric modeling
; atmospheric structure
; computer simulation
; convective system
; evaporation
; heating
; hindcasting
; intertropical convergence zone
; sea surface temperature
; seasonal variation
; troposphere
; weather forecasting
; wind stress
; Pacific Ocean
; Pacific Ocean (West)
英文摘要: The development of systematic biases in climate models used in operational seasonal forecasting adversely affects the quality of forecasts they produce. In this study, we examine the initial evolution of systematic biases in the ECMWF System 4 forecast model, and isolate aspects of the model simulations that lead to the development of these biases. We focus on the tendency of the simulated intertropical convergence zone in the western equatorial Pacific to drift northwards by between 0.5° and 3° of latitude depending on season. Comparing observations with both fully coupled atmosphere–ocean hindcasts and atmosphere-only hindcasts (driven by observed sea-surface temperatures), we show that the northward drift is caused by a cooling of the sea-surface temperature on the Equator. The cooling is associated with anomalous easterly wind stress and excessive evaporation during the first twenty days of hindcast, both of which occur whether air-sea interactions are permitted or not. The easterly wind bias develops immediately after initialisation throughout the lower troposphere; a westerly bias develops in the upper troposphere after about 10 days of hindcast. At this point, the baroclinic structure of the wind bias suggests coupling with errors in convective heating, although the initial wind bias is barotropic in structure and appears to have an alternative origin. © 2017, The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109452
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: National Centre for Atmospheric Science, University of Reading, Reading, United Kingdom; LOCEAN, UPMC, Paris, France; Uni Research, Bjerknes Centre for Climate Research, Bergen, Norway; European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
Recommended Citation:
Shonk J.K.P.,Guilyardi E.,Toniazzo T.,et al. Identifying causes of Western Pacific ITCZ drift in ECMWF System 4 hindcasts[J]. Climate Dynamics,2018-01-01,50(2018-03-04)