Solar variability and the levels of Lake Victoria, East Africa, during the last millenium Article Received: 25 July 2004 Accepted: 25 September 2004 Abstract
A new diatom series with 1–6 year resolution from Lake Victoria, East Africa, shows that lake level minima occurred ca. 820–760, 680–660, 640–620, 370–340, and 220–150 calendar years BP. Inferred lake levels were exceptionally high during most of the ‘Little Ice Age’ (ca. 600–200 calendar years BP). Synchrony between East African high lake levels and prolonged sunspot minima during much of the last millenium may reflect solar variability’s effects on tropical rainfall, but those relationships reversed sign ca. 200 years ago. Historical records also show that Victoria lake levels rose during every peak of the ca. 11-year sunspot cycle since the late 19th century. These findings suggest that, if these apparent tropical sun–climate associations during the last millenium were real, then they were subject to abrupt sign reversals.
Keywords East Africa Diatoms Lake Victoria Paleoclimate Solar variability Sunspots
Electronic Supplementary Material to this article is available at
. http://dx.doi.org/10.1007/s10933-004-4227-2 References Anderson, D.M., Overpeck, J.T., Gupta, A.K. 2002 Increase in the Asian southwest monsoon during the past four centuries Science 297 596 599 Google Scholar
Battarbee R.W., Juggins S., Gasse F., Anderson N.J., Bennion H. and Cameron N.G. 2000. European Diatom Database (EDDI). An information system for palaeoenvironmental reconstruction: European Climate Science ConferenceViennaAustria19–23 October1998, pp.1–10.
Google Scholar Black, D.E., Peterson, L.C., Overpeck, J.T., Kaplan, A., Evans, M.N., Kashgarian, M. 1999 Eight centuries of North Atlantic ocean atmosphere variability Science 286 1709 1713 Google Scholar Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N., Showers, W., Hoffmann, S., Lotti-Bond, R., Hajdas, I., Bonani, G. 2001 Persistent solar influence on North Atlantic climate during the Holocene Science 294 2130 2136 Google Scholar Conway, D. 2002 Extreme rainfall events and lake level changes in East Africa: recent events and historical precedents Odada, E.O. Olago, D.O. eds. The East African Great Lakes: Limnology, Palaeolimnology and Biodiversity Kluwer Dordrecht 63 92 Google Scholar Crowley, T.J. 2000 Causes of climate change over the past 1000 years Science 289 270 277 Google Scholar Denton, G.H., Karlén, W. 1973 Holocene climate variations – their pattern and possible cause Quat. Res. 3 155 205 Google Scholar Gasse, F., Barker, P., Johnson, T.C. 2002 A 24,000 yr diatom record from the northern basin of Lake Malawi Odada, E.O. Olago, D.O. eds. The East African Great Lakes: Limnology, Palaeolimnology and Biodiversity Kluwer Dordrecht 393 414 Google Scholar Haug, G.H., Hughen, K.A., Sigman, D.M., Peterson, L.C., Röhl, U. 2001 Southward migration of the Intertropical Convergence Zone through the Holocene Science 293 1304 1308 Google Scholar Hodell, D.A., Brenner, M., Curtis, J.H., Guilderson, T. 2001 Solar forcing of drought frequency in the Maya lowlands Science 292 1367 1370 Google Scholar
Hoyt D.V. and Schatten K.H. 1997. The Role of the Sun in Climate Change. Oxford University Press, pp. 279.
Google Scholar Jones, P.D., Osborne, T.J., Briffa, K.R. 2001 The evolution of climate over the last millenium Science 292 662 666 Google Scholar Kendall, R.L. 1969 An ecological history of the Lake Victoria basin Ecol. Monogr. 39 121 176 Google Scholar Kelly, P.M. 1977 Solar influence on North Atlantic mean sea level pressure Nature 269 320 322 Google Scholar Kumar, K.K., Rajagopalan, B., Cane, M.A. 1999 On the weakening relationship between the Indian monsoon and ENSO Science 284 214 217 Google Scholar Kutzbach, J.E., Street-Perrott, F.A. 1985 Milankovitch forcing of fluctuations in the level of tropical lakes from 18 to 0 kyr BP Nature 317 130 134 Google Scholar Linthicum, K.J., Anyamba, A., Tucker, C.J., Kelley, P.W., Myers, M.F., Peters, C.J. 1999 Climate and satellite indicators to forecast Rift Valley fever epidemics in Kenya Science 285 397 400 Google Scholar Magny, M. 1993 Solar influences on Holocene climatic changes illustrated by correlations between past lake-level fluctuations and the atmospheric 14 C record Quat. Res. 40 1 9 Google Scholar Mayewski, P.A., Meeker, L.D., Twickler, M.S., Whitlow, S.I., Yang, Q., Prentice, M. 1997 Major features and forcing of high latitude northern hemisphere atmospheric circulation over the last 110,000 years J. Geophys. Res. 102 26,345 26,366 Google Scholar
Meeker L.D., Mayewski P.A. and Bloomfield P. 1995. A new approach to glaciochemical time series analysis. In: Delmas R.J. (ed), Ice Core Studies of Global Biogeochemical Cycles. NATO ASI Series I: Global Environmental ChangeVol. 1. pp. 383–400.
Google Scholar Mensing, S.A., Southon, J.R. 1999 A simple method to separate pollen for AMS radiocarbon dating and its application to lacustrine and marine sediments Radiocarbon 41 1 8 Google Scholar Nicholson, S.E. 2000 The nature of rainfall variability over Africa on time scales of decades to millenia Glob. Planet. Change 26 137 158 Google Scholar Nicholson, S.E., Yin, X. 2001 Rainfall conditions in equatorial East Africa during the nineteenth century as inferred from the record of Lake Victoria Climatic Change 48 387 398 Google Scholar Richard, Y., Trzaska, S., Roucou, P., Rouault, M. 2000 Modification of the southern African rainfall variability/ENSO relathionsip since the late 1960’s Clim. Dynam. 16 883 895 Google Scholar Shindell, D., Rind, D., Balachandran, N., Lean, J., Lonergan, P. 1999 Solar cycle variability, ozoneand climate Science 284 305 308 Google Scholar Stager, J.C., Cumming, B., Meeker, L.D. 1997 An 11,400-yearhigh-resolution diatom record from Lake VictoriaEast Africa Quat. Res. 47 81 89 Google Scholar Stager, J.C., Johnson, T.C. 2000 A 12,400 14 C yr offshore diatom record from east central Lake VictoriaEast Africa J. Paleolimnol. 23 373 383 Google Scholar Stager, J.C., Cumming, B., Meeker, L.D. 2003 A 10,000 year high-resolution diatom record from Pilkington Bay, Lake VictoriaEast Africa Quat. Res. 59 172 181 Google Scholar Stuiver, M., Brauzanias, T.F. 1989 Atmospheric 14C and century-scale solar oscillations Nature 338 405 408 Google Scholar Stuiver, M., Reimer, P.J., Bard, E., Beck, J.W., Burr, G.S., Hughen, K.A., Kromer, B., McCormac, G., van der Plicht, J., Spurk, M. 1998 INTCAL98 Radiocarbon Age Calibration, 24000–0 cal BP Radiocarbon 40 1041 1083 Google Scholar
Sutcliffe J.V. and Parks Y.P. 1999. The hydrology of the Nile. Int. Assoc. Hydrol. Sci. Spec. Publ. 5.
Google Scholar Tate, E.L., Sene, K.J., Sutcliffe, J.V. 2001 A water balance study of the upper White Nile basin flows in the late nineteenth century Hydrol. Sci. J. 46 301 318 Google Scholar Talling, J.F., Talling, I.B. 1965 The chemical composition of African lake waters Int. Rev. ges. Hydrobiol. 50 421 463 Google Scholar Thompson, L.G., et al. 2002 Kilimanjaro ice core records: evidence of Holocene climate change in tropical Africa Science 298 589 593 Google Scholar Tyson, P.D., Lindesay, J.A. 1992 The climate of the last 2000 years in southern Africa The Holocene 2 271 278 Google Scholar van Geel, B., Heusser, C.J., Renssen, H., Schuurmans, C.J.E. 2000 Climatic change in Chile at around 2700 B.P. and global evidence for solar forcing: a hypothesis The Holocene 10 659 664 Google Scholar Verschuren, D., Edgington, D.N., Kling, H.J., Johnson, T.C. 1998 Silica depletion in Lake Victoria: sedimentary signals at offshore stations J. Great Lakes Res. 24 118 130 Google Scholar Verschuren, D., Laird, K.R., Cumming, B.F. 2000 Rainfall and drought in equatorial East Africa during the past 1,100 years Nature 403 410 413 Google Scholar