Multi-proxy summer and winter precipitation reconstruction for southern Africa over the last 200 years
- 870 Downloads
This study presents the first consolidation of palaeoclimate proxy records from multiple archives to develop statistical rainfall reconstructions for southern Africa covering the last two centuries. State-of-the-art ensemble reconstructions reveal multi-decadal rainfall variability in the summer and winter rainfall zones. A decrease in precipitation amount over time is identified in the summer rainfall zone. No significant change in precipitation amount occurred in the winter rainfall zone, but rainfall variability has increased over time. Generally synchronous rainfall fluctuations between the two zones are identified on decadal scales, with common wet (dry) periods reconstructed around 1890 (1930). A strong relationship between seasonal rainfall and sea surface temperatures (SSTs) in the surrounding oceans is confirmed. Coherence among decadal-scale fluctuations of southern African rainfall, regional SST, SSTs in the Pacific Ocean and rainfall in south-eastern Australia suggest SST-rainfall teleconnections across the southern hemisphere. Temporal breakdowns of the SST-rainfall relationship in the southern African regions and the connection between the two rainfall zones are observed, for example during the 1950s. Our results confirm the complex interplay between large-scale teleconnections, regional SSTs and local effects in modulating multi-decadal southern African rainfall variability over long timescales.
KeywordsPrecipitation reconstruction Southern Africa Palaeoclimate Climate dynamics Southern hemisphere
RN and DN would like to thank the University of Brighton for funding to support this study. JZ was supported by an AIMS/CSIRO/UWA collaborative post-doctoral Fellowship.
- Gergis J, Ashcroft L (2012) Rainfall variations in south-eastern Australia part 2: a comparison of documentary, early instrumental and palaeoclimate records, 1788–2008. Int J Climatol. doi: 10.1002/joc.3639
- Gergis J, Gallant A, Braganza K, Karoly DJ, Allen K, Cullen L, D’Arrigo R, Goodwin I, Grierson P, McGregor S (2012) On the long-term context of the 1997–2009 ‘Big Dry’ in south-eastern Australia: insights from a 206-year multi-proxy rainfall reconstruction. Clim Change 111:923–944CrossRefGoogle Scholar
- Neukom R, Luterbacher J, Villalba R, Kuttel M, Frank D, Jones PD, Grosjean M, Wanner H, Aravena JC, Black DE, Christie DA, D’Arrigo R, Lara A, Morales M, Soliz-Gamboa C, Srur A, Urrutia R, von Gunten L (2011) Multiproxy summer and winter surface air temperature field reconstructions for southern South America covering the past centuries. Clim Dyn 37(1–2):35–51. doi: 10.1007/s00382-010-0793-3 CrossRefGoogle Scholar
- Saji N, Goswami G, Vinayachandran P, Yamagata T (1999) A dipole mode in the tropical Indian Ocean. Nature 401:360–363Google Scholar
- Shen C, Wang WC, Gong W, Hao Z (2006) A Pacific decadal oscillation record since 1470 AD reconstructed from proxy data of summer rainfall over eastern China. Geophys Res Lett 33(L03702). doi: 10.1029/2005GL024804
- Smerdon JE (2011) Climate models as a test bed for climate reconstruction methods: pseudoproxy experiments. Wiley Interdisciplinary Reviews: Clim Change. doi: 10.1002/wcc.1149
- Stahle DW, D’Arrigo RD, Krusic PJ, Cleaveland MK, Cook ER, Allan RJ, Cole JE, Dunbar RB, Therrell MD, Gay DA, Moore MD, Stokes MA, Burns BT, Villanueva-Diaz J, Thompson LG (1998) Experimental dendroclimatic reconstruction of the Southern oscillation. Bull Am Meteorol Soc 79(10):2137–2152CrossRefGoogle Scholar
- Tyson PD (1986) Climate change and variability in Southern Africa. Oxford University Press, CapetownGoogle Scholar
- Villalba R, Lara A, Masiokas M, Urrutia R, Cook ER, Christie D, Mundo IA, Boninsegna J, Fenwick P, Neukom R, Allen K, Morales M, Araneo DC, Marshall G, Srur A, Aravena JC, Palmer J (2012) Unusual southern hemisphere tree growth patterns induced by changes in the southern annular mode. Nat Geosci 5:793–798. doi: 10.1038/NGEO1613 CrossRefGoogle Scholar