DOI: 10.1007/s00382-012-1423-z
Scopus记录号: 2-s2.0-84874945796
论文题名: How well do reanalyses represent the southern African precipitation?
作者: Zhang Q. ; Körnich H. ; Holmgren K.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 40, 期: 2017-03-04 起始页码: 951
结束页码: 962
语种: 英语
英文关键词: Dipole
; Hydrological cycle
; Precipitation
; Reanalysis
; Southern Africa
英文摘要: Monthly-mean precipitation observations over southern Africa are used to evaluate the performance of eight global reanalyses: ERA-40, ERA-interim, JRA-25, MERRA, CFSR, NCEP-R1, NCEP-R2 and 20CRv2. All eight reanalyses reproduce the regionally averaged seasonal cycle fairly well; a few spatial mismatches with the observations are found in the climate mean for the rainy season. Principal component analyses show a dipole in the leading modes of all reanalyses, however with crucial differences in its spatial position. Possible reasons for the differences between the reanalyses are discussed on the basis of the ERA-interim and 20CRv2 results. A comparison between the moisture transports shows that ERA-interim manifests a very strong moisture convergence over the eastern equatorial Atlantic, resulting in the strong precipitation here. This excessive convergence may be due to the water-vapor assimilation and convection parameterization. Over the Indian Ocean, the ITCZ is shifted northward in ERA-interim compared to its position in 20CRv2. This discrepancy is most likely attributable to the meridional SST gradients in the Indian Ocean which are significantly larger in the ERA-interim than those in the 20CRv2, and the resulting atmospheric response prevents a southward shift of the ITCZ. Overall, the consistent description of the dynamical circulation of the atmosphere and the hydrological cycle appears as a crucial benchmark for reanalysis data. Based on our evaluation, the preferential reanalysis for investigating the climate variability over southern Africa is 20CRv2 that furthermore spans the longest time period, hence permitting the most precise investigations of interannual to decadal variability. © 2012 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54949
Appears in Collections: 过去全球变化的重建
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作者单位: Bert Bolin Centre for Climate Research, Stockholm University, 106 91 Stockholm, Sweden; Department of Meteorology, Stockholm University, 106 91 Stockholm, Sweden; Department of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm, Sweden
Recommended Citation:
Zhang Q.,Körnich H.,Holmgren K.. How well do reanalyses represent the southern African precipitation?[J]. Climate Dynamics,2013-01-01,40(2017-03-04)