DOI: 10.1007/s00382-016-3016-8
Scopus记录号: 2-s2.0-84958787265
论文题名: West African monsoon intraseasonal activity and its daily precipitation indices in regional climate models: diagnostics and challenges
作者: Poan E.D. ; Gachon P. ; Dueymes G. ; Diaconescu E. ; Laprise R. ; Seidou Sanda I.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 47, 期: 2017-09-10 起始页码: 3113
结束页码: 3140
语种: 英语
英文关键词: Intraseasonal variability
; Precipitation indices
; Regional climate modeling
; West African monsoon
英文摘要: The West African monsoon intraseasonal variability has huge socio-economic impacts on local populations but understanding and predicting it still remains a challenge for the weather prediction and climate scientific community. This paper analyses an ensemble of simulations from six regional climate models (RCMs) taking part in the coordinated regional downscaling experiment, the ECMWF ERA-Interim reanalysis (ERAI) and three satellite-based and observationally-constrained daily precipitation datasets, to assess the performance of the RCMs with regard to the intraseasonal variability. A joint analysis of seasonal-mean precipitation and the total column water vapor (also called precipitable water—PW) suggests the existence of important links at different timescales between these two variables over the Sahel and highlights the relevance of using PW to follow the monsoon seasonal cycle. RCMs that fail to represent the seasonal-mean position and amplitude of the meridional gradient of PW show the largest discrepancies with respect to seasonal-mean observed precipitation. For both ERAI and RCMs, spectral decompositions of daily PW as well as rainfall show an overestimation of low-frequency activity (at timescales longer than 10 days) at the expense of the synoptic (timescales shorter than 10 days) activity. Consequently, the effects of the African Easterly Waves and the associated mesoscale convective systems are substantially underestimated, especially over continental regions. Finally, the study investigates the skill of the models with respect to hydro-climatic indices related to the occurrence, intensity and frequency of precipitation events at the intraseasonal scale. Although most of these indices are generally better reproduced with RCMs than reanalysis products, this study indicates that RCMs still need to be improved (especially with respect to their subgrid-scale parameterization schemes) to be able to reproduce the intraseasonal variance spectrum adequately. © 2016, The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53487
Appears in Collections: 过去全球变化的重建
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作者单位: Centre pour l’Étude et la Simulation du climat à l’Échelle Régionale (ESCER), Dép. des sciences de la Terre et de l’atmosphère, Université du Québec à Montréal (UQAM), PO Box 8888, Stn. Downtown, Montreal, QC, Canada; Centre Eau Terre Environnement, Institut national de la recherche scientifique (INRS), Quebec, QC, Canada; AGRHYMET Regional Centre, Niamey, Niger
Recommended Citation:
Poan E.D.,Gachon P.,Dueymes G.,et al. West African monsoon intraseasonal activity and its daily precipitation indices in regional climate models: diagnostics and challenges[J]. Climate Dynamics,2016-01-01,47(2017-09-10)