Climate Dynamics

, Volume 40, Issue 3–4, pp 951–962 | Cite as

How well do reanalyses represent the southern African precipitation?

  • Qiong ZhangEmail author
  • Heiner Körnich
  • Karin Holmgren


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.


Reanalysis Precipitation Southern Africa Hydrological cycle Dipole 



This work was supported by the Swedish Research Council project Holocene climate variability in southern Africa and by the Bert Bolin Centre for Climate research. We are very grateful to the two anonymous reviewers and the editor Susanna Corti for their helpful comments and suggestions.


  1. Andersson E, Bauer P, Beljaars A, Chevallier F, Hólm E, Janisková M, Kållberg P, Kelly GA, Lopez P, McNally A, Moreau E, Simmons AJ, Thépaut JN, Tompkins AM (2005) Assimilation and modeling of the atmospheric hydrological cycle in the ECMWF forecasting system. Bull Am Meteor Soc 86:387–402CrossRefGoogle Scholar
  2. Andersson E, Hólm E, Bauer P, Beljaars A, Kelly GA, McNally AP, Simmons AJ, Thépaut JN, Tompkins AM (2007) Analysis and forecast impact of the main humidity observing systems. Q J Roy Meteor Soc 133:1473–1485Google Scholar
  3. Bengtsson L, Haines K, Hodges KI, Arkin P, Berrisford P, Bougeault P, Kållberg P, Simmons AJ, Uppala S, Folland CK, Gordon C, Rayner N, Thorne PW, Jones P, Stammer D, Vose RS (2007) The need for a dynamical climate re-analysis. Bull Am Meteor Soc 88:495–501CrossRefGoogle Scholar
  4. Bett AK, Zhao M, Dirmeyer PA, Beljaars ACM (2006) Comparison of ERA-40 and NCEP/DOE near-surface data sets with other ISLSCP-II data sets. J Geophys Res 111:D22S04. doi: 10.1029/2006JD007174 CrossRefGoogle Scholar
  5. Bosilovich M, Chen J, Robertson FR, Adler RF (2008) Evaluation of global precipitation in reanalyses. J Appl Meteorol Climatol 47:2279–2299. doi: 10.1175/2008JAMC1921.1 CrossRefGoogle Scholar
  6. Bosilovich M, Robertson FR, Chen J (2011) Global energy and water budgets in MERRA. J Clim 24:5721–5739CrossRefGoogle Scholar
  7. Bromwich DH, Nicolas JP, Monaghan AJ (2011) An Assessment of precipitation changes over Antarctica and the Southern Ocean since 1989 in contemporary global reanalyses. J Clim 24:4189–4209. doi: 10.1175/2011JCLI4074.1 CrossRefGoogle Scholar
  8. Compo GP, Whitaker JS, Sardeshmukh PD, Matsui N, Allan RJ, Yin X, Gleason BE, Vose RS, Rutledge G, Bessemoulin P, Brönnimann S, Brunet M, Crouthamel RI, Grant AN, Groisman PY, Jones PD, Kruk MC, Kruger AC, Marshall GJ, Maugeri M, Mok HY, Nordli Ø, Ross TF, Trigo RM, Wang XL, Woodruff SD, Worley SJ (2011) The twentieth century reanalysis project. Q J Roy Meteor Soc 137:1–28. doi: 10.1002/qj.776 CrossRefGoogle Scholar
  9. Cook KH (2000) The South Indian convergence zone and interannual rainfall variability over southern Africa. J Clim 13:3789–3804CrossRefGoogle Scholar
  10. Dee DP, Uppala S (2009) Variational bias correction of satellite radiance data in the ERA-interim reanalysis. Q J Roy Meteor Soc 135:1830–1841CrossRefGoogle Scholar
  11. Dee DP, Uppala SM, Simmons AJ, Berrisford P, Poli P, Kobayashi S, Andrae U, Balmaseda MA, Balsamo G, Bauer P, Bechtold P, Beljaars ACM, van de Berg L, Bidlot J, Bormann N, Delsol C, Dragani R, Fuentes M, Geer AJ, Haimberger L, Healy SB, Hersbach H, Hólm EV, Isaksen L, Kållberg P, Köhler M, Matricardi M, McNally AP, Monge-Sanz BM, Morcrette J-J, Park B-K, Peubey C, de Rosnay P, Tavolato C, Thépaut J-N, Vitart F (2011) The ERA-interim reanalysis: configuration and performance of the data assimilation system. Q J Roy Meteor Soc 137:553–597. doi: 10.1002/qj.828 CrossRefGoogle Scholar
  12. Giannini A, Biasutti M, Held IM, Sobel AH (2008) A global perspective on African climate. Climatic Change 90:359–383CrossRefGoogle Scholar
  13. Gill AE (1980) Some simple solutions for heat-induced tropical circulation. Q J Roy Meteor Soc 106:447–462CrossRefGoogle Scholar
  14. Goddard L, Graham NE (1999) Importance of the Indian Ocean for simulating rainfall anomalies over eastern and southern Africa. J Geophys Res 104:19099–19116CrossRefGoogle Scholar
  15. Hoffmann G, Werner M, Heimann M (1998) Water isotope module of the ECHAM atmospheric general circulation model: a study on timescales from days to several years. J Geophys Res 103(D14):16871–16896CrossRefGoogle Scholar
  16. Holmgren K, Öberg H (2006) Climate Change in Southern and East Africa during the Past Millennium and its implications for societal development. Env Dev Sust 8:185–195CrossRefGoogle Scholar
  17. Joussaume S, Jouzel J, Sadourny R (1984) A general circulation model of water isotope cycles in the atmosphere. Nature 311:24–29CrossRefGoogle Scholar
  18. Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woollen J (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteorol Soc 77(3):437–471CrossRefGoogle Scholar
  19. Kanamitsu M, Ebisuzaki W, Woollen J, Yang S-K, Hnilo J, Fiorino M, Potter GL (2002) NCEP-DOE AMIP-2 reanalysis (R-2). Bull Atmos Met Soc 83:1631–1643CrossRefGoogle Scholar
  20. Lyons SW (1991) Origins of convective variability over equatorial southern Africa during austral summer. J Clim 4:23–39CrossRefGoogle Scholar
  21. Mason SJ, Goddard L (2001) Probabilistic precipitation anomalies associated with ENSO. Bull Am Meteorol Soc 82:619–638CrossRefGoogle Scholar
  22. Mitchell TD, Jones PD (2005) An improved method of constructing a database of monthly climate observations and associated high resolution grids. Int J Climatol 25:693–712CrossRefGoogle Scholar
  23. Nicholson SE, Kim J (1997) The relationship of the El Niño–Southern oscillation to African rainfall. Int J Climatol 17:117–135CrossRefGoogle Scholar
  24. Ogallo LJ (1989) The spatial and temporal patterns of the East African seasonal rainfall derived from principal component analysis. Int J Climatology 9:145–167CrossRefGoogle Scholar
  25. Onogi K, Tsutsui J, Koide H, Sakamoto M, Kobayashi S, Hatsushika H, Matsumoto T, Yamazaki N, Kamahori H, Takahashi K, Kadokura S, Wada K, Kato K, Oyama R, Ose T, Mannoji N, Taira R (2007) The JRA-25 reanalysis. J Meteorol Soc Jpn 85:369–432CrossRefGoogle Scholar
  26. Reason CJC, Jagadheesha D (2005) A model investigation of recent ENSO impacts over southern Africa. Meteorol Atmos Phys 89:181–205CrossRefGoogle Scholar
  27. Rienecker MM et al (2011) MERRA: NASA’s modern-era retrospective analysis for research and applications. J Clim 24:3624–3648CrossRefGoogle Scholar
  28. Saha S, Moorthi S, Pan H-L, Wu X, Wang J, Nadiga S, Tripp P, Kistler R, Woollen J, Behringer D, Liu H, Stokes D, Grumbine R, Gayno G, Hou Y-T, Chuang H-Y, JuangH-MH Sela J, Iredell M, Treadon R, Kleist D, vanDelst P, Keyser D, Derber J, Ek M, Meng J, Wei H, Lord S, Yang R, van den Dool H, Kumar A, Wang W, Long C, Chelliah M, Xue Y, Huang B, Schemm J-K, Ebisuzaki W, Lin R, Xie P, Chen M, Zhou S, Higgins W, Zou C-Z, Liu Q, Chen Y, Han Y, Cucurull L, Reynolds RW, Rutledge G, Goldberg M (2010) The NCEP climate forecast system reanalysis. Bull Am Meteorol Soc 91:1015–1057CrossRefGoogle Scholar
  29. Simmons A, Uppala S, Dee D, Kobayashi S (2007) ERA-Interim: new ECMWF reanalysis products from 1989 onwards. ECMWF Newsl 110:25–35Google Scholar
  30. Sturm C, Zhang Q, Noone D (2010) An introduction to stable water isotopes in climate models: benefits of forward proxy modelling for paleoclimatology. Clim Past 6:115–129. doi: 10.5194/cp-6-115-2010 CrossRefGoogle Scholar
  31. Todd M, Washington R (1998) Extreme daily rainfall in southern Africa and southwest Indian Ocean: tropical–temperate links. South Afr J Sci 94:64–70Google Scholar
  32. Tompkins AM, Bechtold P, Beljaars ACM, Benedetti A, Cheinet S, Janiskova M, Köhler M, Lopez P, Morcrette JJ (2004) Moist physical processes in the IFS: Progress and plans. ECMWF Tech Memo, European Centre for Medium-Range Weather Forecasts, Reading, p 93Google Scholar
  33. Tyson PD, Lee-Thorp J, Holmgren K, Thackeray JF (2002) Changing gradients of climate change in southern Africa during the past millennium: implications for population movements. Clim Change 52:129–135CrossRefGoogle Scholar
  34. Uppala SM, Kållberg PW, Simmons AJ, Andrae U, da Costa Bechtold V, Fiorino M, Gibson JK, Haseler J, Hernandez A, Kelly GA, Li X, Onogi K, Saarinen S, Sokka N, Allan RP, Andersson E, Arpe K, Balmaseda MA, Beljaars ACM, van de Berg L, Bidlot J, Bormann N, Caires S, Dethof A, Dragosavac M, Fisher M, Fuentes M, Hagemann S, Hólm E, Hoskins BJ, Isaksen L, Janssen PAEM, McNally AP, Mahfouf J-F, Jenne R, Morcrette J-J, Rayner NA, Saunders RW, Simon P, Sterl A, Trenberth KE, Untch A, Vasiljevic D, Viterbo P, Woollen J (2005) The ERA-40 reanalysis. Q J Roy Meteor Soc 131:2961–3012. doi: 10.1256/qj.04.176 CrossRefGoogle Scholar
  35. Vigaud N, Richard Y, Rouault M, Fauchereau N (2009) Moisture transport between the South Atlantic Ocean and southern Africa: relationships with summer rainfall and associated dynamics. Clim Dyn 32:113–123CrossRefGoogle Scholar
  36. Vuille M, Werner M, Bradley RS, Chan RS, Keimig F (2005) Stable isotopes in east African short precipitation record Indian Ocean zonal mode. Geophys Res Lett 32:21. doi: 10.1029/2005GL023876,2005 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Qiong Zhang
    • 1
    • 2
    Email author
  • Heiner Körnich
    • 1
    • 2
  • Karin Holmgren
    • 1
    • 3
  1. 1.Bert Bolin Centre for Climate ResearchStockholm UniversityStockholmSweden
  2. 2.Department of MeteorologyStockholm UniversityStockholmSweden
  3. 3.Department of Physical Geography and Quaternary GeologyStockholm UniversityStockholmSweden

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