Climate Dynamics

, Volume 46, Issue 5, pp 1799–1818

Spatial distribution of precipitation annual cycles over South Africa in 10 CORDEX regional climate model present-day simulations

  • Alice Favre
  • Nathalie Philippon
  • Benjamin Pohl
  • Evangelia-Anna Kalognomou
  • Christopher Lennard
  • Bruce Hewitson
  • Grigori Nikulin
  • Alessandro Dosio
  • Hans-Juergen Panitz
  • Ruth Cerezo-Mota
Article

DOI: 10.1007/s00382-015-2677-z

Cite this article as:
Favre, A., Philippon, N., Pohl, B. et al. Clim Dyn (2016) 46: 1799. doi:10.1007/s00382-015-2677-z

Abstract

This study presents an evaluation of the ability of 10 regional climate models (RCMs) participating in the COordinated Regional climate Downscaling Experiment-Africa to reproduce the present-day spatial distribution of annual cycles of precipitation over the South African region and its borders. As found in previous studies, annual mean precipitation is quasi-systematically overestimated by the RCMs over a large part of southern Africa south of about 20°S and more strongly over South Africa. The spatial analysis of precipitation over the studied region shows that in most models the distribution of biases appears to be linked to orography. Wet biases are quasi-systematic in regions with higher elevation with inversely neutral to dry biases particularly in the coastal fringes. This spatial pattern of biases is particularly obvious during summer and specifically at the beginning of the rainy season (November and December) when the wet biases are found to be the strongest across all models. Applying a k-means algorithm, a classification of annual cycles is performed using observed precipitation data, and is compared with those derived from modeled data. It is found that the in-homogeneity of the spatial and temporal distribution of biases tends to impact the modeled seasonality of precipitation. Generally, the pattern of rainfall seasonality in the ensemble mean of the 10 RCMs tends to be shifted to the southwest. This spatial shift is mainly linked to a strong overestimation of convective precipitation at the beginning of the rainy season over the plateau inducing an early annual peak and to an underestimation of stratiform rainfall in winter and spring over southwestern South Africa.

Keywords

CORDEX-Africa Regional climate model Evaluation Annual cycle of precipitation 

Supplementary material

382_2015_2677_MOESM1_ESM.docx (942 kb)
Supplementary material 1 (DOCX 941 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Alice Favre
    • 1
  • Nathalie Philippon
    • 1
  • Benjamin Pohl
    • 1
  • Evangelia-Anna Kalognomou
    • 2
    • 3
  • Christopher Lennard
    • 2
  • Bruce Hewitson
    • 2
  • Grigori Nikulin
    • 4
  • Alessandro Dosio
    • 5
  • Hans-Juergen Panitz
    • 6
  • Ruth Cerezo-Mota
    • 7
  1. 1.Centre de Recherches de Climatologie (CRC), CNRS UMR 6282 BiogéosciencesUniversité de BourgogneDijonFrance
  2. 2.CSAG, ENGEO DepartmentUniversity of Cape TownCape TownSouth Africa
  3. 3.Laboratory of Heat Transfer and Environmental Engineering (LHTEE)Aristotle UniversityThessaloníkiGreece
  4. 4.Rossby CentreSwedish Meteorological and Hydrological Institute (SMHI)NorrköpingSweden
  5. 5.European Commission Joint Research CentreInstitute for Environment and SustainabilityIspraItaly
  6. 6.Institute for Meteorology and Climate Research – Troposphere ResearchKarlsruhe Institute of TechnologyKarlsruheGermany
  7. 7.Laboratorio de Ingenería y Procesos CosterosUNAMSisalMexico

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