Abrupt changes in the water balance of tropical West Africa during the late quaternary

Journal of Geophysical Research Atmospheres

Volumn 113, Issue 12, 2008, Pages

  Shanahan, Timothy M ^a   Overpeck, Jonathan T ^b   Scholz, Christopher A ^c   Beck, J Warren ^d   Peck, John ^e   King, John W ^f  

^a WOODS HOLE OCEANOGRAPHIC INSTITUTION   (United States)

^b University of Arizona   (United States)

^c SYRACUSE UNIVERSITY   (United States)

^d UNIVERSITY OF ARIZONA   (United States)

^e UNIVERSITY OF AKRON   (United States)

^f UNIVERSITY OF RHODE ISLAND   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ATMOSPHERIC HUMIDITY; ATMOSPHERIC TEMPERATURE; CLIMATE CHANGE; DROUGHT; HYDROLOGY; LAKES; MATHEMATICAL MODELS; PRECIPITATION (METEOROLOGY);

CLIMATE FORCING; CLIMATE VARIATION; GENERAL CIRCULATION MODEL; HYDROLOGICAL MODELING; HYDROLOGICAL RESPONSE; LAKE LEVEL; MONSOON; NORTHERN HEMISPHERE; PRECIPITATION (CLIMATOLOGY); SIMULATION; WATER BUDGET;

AFRICA; ASHANTI; GHANA; LAKE BOSUMTWI; SUB-SAHARAN AFRICA; WEST AFRICA;

EID: 50049094216     PISSN: 01480227     EISSN: None     Source Type: Journal    
DOI: 10.1029/2007JD009320     Document Type: Article

References (108)

1. Alley, R. B., and A. M. Agustsdottir (2005), The 8 k event: Cause and consequences of a major Holocene abrupt climate change, Quat. Sci. Rev., 24, 1123-1149, doi:10.1016/j.quascirev.2004.12.004.
2. Alley, R. B., P. A. Mayewski, T. Sowers, M. Stuiver, K. C. Taylor, and P. U. Clark (1997), Holocene climatic instability: A prominent, widespread event 8200 yr ago, Geology, 25, 483-486, doi:10.1130/ 00917613(1997)025<0483:HCIAPW>2.3.CO;2.
3. Andrews, J. N., J.-C. Fontes, J.-F. Aranyossy, A. Dodo, W. M. Edmunds, A. Joseph, and Y. Travi (1994), The evolution of alkaline groundwater in the Continental Intercalaire aquifer of the Irhazer plain, Niger, Water Resour Res., 30, 45-61.
4. Baker, T. R., M. D. Swaine, and D. Burslem (2003), Variation in tropical forest growth rates: Combined effects of functional group composition and resource availability, Perspect. Plant Ecol. Evol. Syst., 6, 21-36, doi:10.1078/1433-8319-00040.
5. Barber, D. C., et al. (1999), Forcing of the cold event of 8,200 years age by catastrophic drainage of Laurentide Lakes, Nature, 400, 344-348, doi:10.1038/22504.
6. Bauer, E., A. Ganapolski, and M. Montoya (2004), Simulation of the cold climate event 8200 years ago by meltwater outburst from Lake Agassiz, Paleoceanography, 19, PA3014, doi:10.1029/2004PA001030.
7. Bergner, A. G. N., M. H. Trauth, and B. Bookbagen (2003), Paleoprecipitation estimates for the Lake Naivasha basin (Kenya) during the last 175 k.y. using a lake-balance model, Global Planet. Change, 36, 117-136, doi:10.1016/S0921-8181(02)00178-9.
8. Bergonzini, L., F. Chalie, and F. Gasse (1997), Paleoevaporation and paleoprecipitation in the Tanganyika Basin at 18,000 years B.P. inferred from hydrologic and vegetation proxies, Quat. Res., 47, 295-305, doi:10.1006/qres.1996.1879.
9. Bonfils, C., N. de Noblet-Ducoure, P. Braconnot, and S. Joussaume (2001), Hot desert albedo and climate change: Mid-Holocene monsoon in North Africa, J. Clim., 14, 3724-3737, doi:10.1175/ 15200442(2001)014<3724:HDAACC>2.0.CO;2.
10. Bonnefille, R., and F. Chalie (2000), Pollen-inferred precipitation time-series from equatorial mountains, Africa, the last 40 kyr BP, Global Planet. Change, 26, 25-50.
11. Braconnot, P., S. Joussaume, N. de Noblet, and G. Ramstein (2000), Mid-Holocene and last Glacial Maximum African monsoon changes as simulated within the Paleoclimate Modelling Intercomparison Project, Global Planet. Change, 26, 51-66, doi:10.1016 /S0921-8181(00)00033-3.
12. Broecker, W. S. (2003), Does the trigger for abrupt climate change reside in the ocean or in the atmosphere?, Science, 300, 1519-1522, doi:10.1126/science.1083797.
13. Broecker, W. S., D. Peteet, I. Hajdas, J. Lin, and E. Clark (1998), Antiphasing between rainfall in Africa's rift valley and north America's great basin, Quat. Res., 50, 12-20, doi:10.1006/qres.1998.1973.
14. Brooks, K., C. A. Scholz, J. W. King, J. Peck, J. T. Overpeck, J. M. Russell, and P. Y. O. Amoako (2005), Late-Quatemary lowstands of lake Bosumtwi, Ghana: Evidence from high-resolution seismic-reflection and sediment-core data, Palaeogeogr. Palaeoclimatol. Palaeoecol., 216, 235-249, doi:10.1016/j.palaeo.2004.10.005.
15. Butzer, K. W., G. L. Isaac, J. L. Richardson, and C. Washbourn-Kamau (1972), Radiocarbon dating of East African lake levels, Science, 175, 1069-1076.
16. Chiang, J. C. H., M. Biasutti, and D. S. Battisti (2003), Sensitivity of the Atlantic Intertropical Convergence Zone to Last Glacial Maximum boundary conditions, Paleoceanography, 18(4), 1094, doi:10.1029/ 2003PA000916.
17. Crowley, T. J. (2000), Causes of climate change over the past 1000 years, Science, 289, 270-277, doi:10.1126/science.289.5477.270.
18. Crucifix, M., and C. D. Hewitt (2005), Impact of vegetation changes on the dynamics of the atmosphere at the Last Glacial Maximum, Clim. Dyn., 25, 447-459, doi:10.1007/s00382-005-0013-8.
19. Dahl, K. A., A. J. Broccoli, and R. J. Stouffer (2005), Assessing the role of North Atlantic freshwater forcing in millennial scale climate variability: A tropical Atlantic perspective, Clim. Dyn., 24, 325-346, doi:10.1007/s00382-004-0499-5.
20. deMenocal, P., J. Ortiz, T. Guilderson, and M. Sarnthein (2000), Coherent high- and low-latitude climate variability during the Holocene warm period, Science, 288, 2198-2202.
21. Edmunds, W. M., E. Fellman, and I. B. Goni (1999), Lakes, groundwater and palaeohydrology in the Sahel of NE Nigeria: Evidence from hydrogeochemistry, J. Geol. Soc., 156, 345-355.
22. Farrera, I., et al. (1999), Tropical climates at the Last Glacial Maximum: a new synthesis of terrestrial palaeoclimate data. I. Vegetation, lake levels and geochemistry, Clim. Dyn., 15, 823-856.
23. Fawcett, P. J., A. M. Agustsdottir, R. B. Alley, and C. A. Shuman (1997), The Younger Dryas termination and North Atlantic Deep Water formation: Insights from climate model simulations and Greenland Ice cores, Paleoceanography, 12, 23-38, doi:10.1029/96PA02711.
24. Ganapolski, A., S. Rahmsdorf, V. Petoukhov, and M. Claussen (1998), Simulation of modern and glacial climates with a coupled global model of intermediate complexity, Nature, 391, 351-356, doi:10.1038/34839.
25. Gasse, F. (1977), Evolution of Lake Abhe (Ethiopia and TFAI), from 70,000 b.p, Nature, 265, 42-45, doi:10.1038/265042a0.
26. Gasse, F. (2000), Hydrological changes in the African tropics since the Last Glacial Maximum, Quat. Sci. Rev., 19, 189-211, doi:10.1016/ S02773791(99)00061-X.
27. Gasse, F., R. Tehet, A. Durand, E. Gilbert, and J. C. Fontes (1990), The arid-humid transition in the Sahara and the Sabel during the last deglaciation, Nature, 346, 141-146, doi:10.1038/34614la0.
28. Gillespie, R., F. A. Street-Perrott, and R. Switsur (1983), Post-glacial arid episodes in Ethiopia have implications for climate prediction, Nature, 306, 680-682, doi:10.1038/306680a0.
29. Grist, J. P., and S. E. Nicholson (2001), A study of the dynamic factors influencing the rainfall variability in the West African Sabel, J. Clim., 14, 1337-1359, doi:10.1175 /1520-0442(2001)014<1337:ASOTDF>2.0. CO;2.
30. Gu, G., and R. F. Adler (2004), Seasonal evolution and variability associated with the West African monsoon system, J. Clim., 17, 3364-3377, doi:10.1175/1520-0442(2004)017<3364:SEAVAW>2.0.CO;2.
31. Hastenrath, S., and J. E. Kutzbach (1983), Paleoclimatic; estimates from water and energy budgets of East African lakes, Quat. Res., 19,141-153.
32. Hippler, D., A. Eisenhauer, and T. F. Nagler (2006), Tropical Atlantic SST history inferred from Ca isotope thermometry over the last 140 ka, Geochim. Cosmochim. Acta, 70, 90-100.
33. Hoelzmann, P., H. J. Kruse, and F. Rottinger (2000), Precipitation estimates for the eastern Saharan palaeomonsoon based on a water balance model of the West Nubian Palaeolake Basin, Global Planet. Change, 26, 105-120, doi:10.1016/S0921-8181(00)00038-2.
34. Jansen, F., et al. (2007), Palaeoclimate, in Climate Change 2007: The Physical Science Basis-Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by S. Solomon et al., Cambridge Univ. Press, New York.
35. Jones, G. S., J. M. Gregory, P. A. Stott, S. F. B. Tett, and R. B. Thorpe (2005), An AOGCM simulation of the climate response to a volcanic super-eruption, Clim. Dyn., 25, 725-738.
36. Joussaume, S., et al. (1999), Monsoon changes for 6000 year ago: Results of 18 simulations for the Paleoclimate Modeling Intercomparison Project (PMIP), Geophys. Res. Lett., 26, 859-862, doi: 10.1029/ 1999GL900126.
37. Kim, J. H., and R. R. Schneider (2003), Low-latitude control of interhemispheric sea-surface temperature contrast in the tropical Atlantic over the past 21 kyears: The possible role of SE trade winds, Clim. Dyn., 21, 337-347.
38. Kim, J.-H., R. R. Schneider, P. J. Muller, and G. Wefer (2002), Interhemispheric comparison of deglacial sea-surface temperature patterns in Atlantic eastern boundary currents, Earth Planet. Sci. Lett., 194, 383-393.
39. Kitoh, A., S. Murakami, and H. Koide (2001), A simulation of the Last Glacial Maximum with a coupled atmosphere-ocean GCM, Geophys. Res. Lett., 28, 2221-2224, doi:10.1029/2000GL012271.
40. Kodera, K. (2004), Solar influence on the Indian Monsoon through dynamical processes, Geophys. Res. Lett., 31, L24209, doi:10.1029/ 2004GL020928.
41. Kutzbach, J. E. (1980), Estimates of past climate at Paleolake Chad, North Africa, based on a hydrological and energy balance model, Quat. Res., 14, 210-223, doi:10.1016/0033-5894(80)90049-6.
42. Kutzbach, J. E., and B. Otto-Bliesner (1982), The sensitivity of the African-Asian monsoon climate to orbital parameter changes for 9000 years BP in a low-resolution general circulation model, J. Atmos. Sci., 39, 1177-1188, doi:10.1175/ 1520-0469(1982)039<1177:TSOTAA>2.0.CO;2.
43. Kutzbach, J. E., and F. A. Street-Perrot (1985), Milanovitch forcing of fluctuations in the level of tropical lakes from 19 to 0 kyr BP, Nature, 317, 130-134, doi:10.1038/317130a0.
44. Lea, D. W., D. K. Pak, L. C. Peterson, and K. A. Hughen (2003), Synchroneity of tropical and high-latitude Atlantic temperatures over the last glacial termination, Science, 301, 1361-1364.
45. LeGrande, A. N., G. A. Schmidt, D. T. Schindell, C. V. Field, R. L. Miller, D. M. Koch, G. Faluvegi, and G. Hoffmann (2006), Consistent simulations of multiple proxy responses to an abrupt climate change event, Proc. Natl. Acad. Sci. U. S. A., 103, 837-842, doi:10.1073/ pnas.0510095103.
46. Levis, S., G. B. Bonan, and C. Bonfils (2004), Soil feedback drives the mid-Holocene North African monsoon northward in fully coupled CCSM2 simulations with a dynamic vegetation model, Clim. Dyn., 23, 791-802, doi:10.1007/s00382-004-0477-y.
47. Liu, Z., B. Otto-Bliesner, J. Kutzbach, L. Li, and C. Shields (2003), Coupled climate simulation of the evolution of global monsoons in the Holocene, J. Clim., 16, 2472-2490, doi:10.1175/ 1520-0442(2003)016<2472:CCSOTE>2.0.CO;2.
48. Liu, Z., et al. (2007), Simulating the transient evolution and abrupt change of Northern Africa atmosphere-ocean-terrestrial ecosystem in the Holocene, Quat. Sci. Rev., 26, 1818-1837, doi:10.1016/ j.quascirev.2007.03.002.
49. Maley, J. (1989), Late Quaternary climatic changes in the African rain forest: Forest refugia and the major role of sea surface temperature variations, in Paleoclimatology and Paleometeorology: Modern and Past Patterns of Global Atmospheric Circulation, edited by M. Leinen and M. Sarnthein, pp. 585-616, Springer, New York.
50. Manabe, S., and R. J. Stauffer (1995), Simulation of abrupt climate change induced by freshwater input to the North Atlantic, Nature, 378, 165-167, doi:10.1038/378165a0.
51. Mees, F., D. Verschuren, R. Nijs, and H. Dumont (1991), Holocene evolution of the crater lake at Malha, northwest Sudan, J. Paleolimnol., 5, 227-253, doi:10.1007/BF00200347.
52. Moron, V. (1994), Guinean and Sahelian rainfall anomaly indices at annual and monthly scale (1933-1990), Int. J. Climatol., 14, 325-341, doi:10.1002/joc.3370140306.
53. Nicholson, S. E. (2001), Climatic and environmental change in Africa during the last two centuries, Clim. Res., 17, 123-144, doi:10.3354/cr017123.
54. Nicholson, S. E., and J. P. Grist (2001), A conceptual model for understanding rainfall variability in the West African Sahel on interannual and interdecadal timescales, Int. J. Climatol., 21, 1733-1757, doi:10.1002/joc.648.
55. Nicholson, S. E., and X. Yin (2001), Rainfall variability in equatorial East Africa during the nineteenth century as inferred from the record of Lake Victoria, Clim. Change, 48, 387-398.
56. North Greenland Ice Core Project Members (2004), High-resolution record of Northern Hemisphere climate extending into the last interglacial period, Nature, 431, 147-151, doi:10.1038/nature02805.
57. Nurnberg, D., A. Muller, and R. R. Schneider (2000), Paleo-sea surface temperature calculations in the equatorial east Atlantic from Mg/Ca ratios in planktic foraminifera: A comparison to sea surface temperature estimates from U-37 (K′), oxygen isotopes, and foraminiferal transfer function, Paleoceanography, 15, 124-134.
58. Nyberg, J., B. A. Malmgren, A. Kuijpers, and A. Winter (2002), A centennial-scale variability of tropical North Atlantic surface hydrography during the late Holocene, Palaeogeogr. Palaeoclimatol. Palaeoecol., 183, 25-41, doi:10.1016/S0031-0182(01)00446-1.
59. Opoku-Ankomah, Y., and I. Cordery (1994), Atlantic sea surface temperatures and rainfall variability in Ghana, J. Clim., 7, 551-558, doi:10.1175/1520-0442(1994)007<0551:ASSTAR>2.0.CO;2.
60. Otto-Bliesner, B., E. C. Brady, G. Clauzet, R. Tomas, S. Levis, and Z. Kothavala (2006), Last Glacial Maximum and Holocene climate in CCSM3, J. Clim., 19, 2526-2544, doi:10.1175/JCLI3748.1.
61. Overpeck, J. T., and J. E. Cole (2006), Abrupt change in Earth's climate system, Annu. Rev. Environ. Resour., 31, 1-31, doi:10.1146/ annurev.energy.30.050504.144308.
62. Overpeck, J., D. Anderson, S. Trumbore, and W. Prell (1996), The southwest Indian Monsoon over the last 18000 years, Clim. Dyn., 12, 213-225, doi:10.1007/BF00211619.
63. Peck, J. A., R. R. Green, T. Shanahan, J. W. King, J. T. Overpeck, and C. A. Scholz (2004), A magnetic mineral record of Late Quaternary tropical climate variability from Lake Bosumtwi, Ghana, Palaeogeogr. Palaeoclimatol. Palaeoecol., 215, 37-57.
64. Peck, J. A., et al. (2005), The Lake Bosumtwi Drilling Project: A 1 Ma West African paleoclimate record, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract PP13C-02.
65. Polissar, P. J., M. B. Abbott, A. P. Wolfe, A. Bezada, V. Rull, and R. S. Bradley (2006), Solar modulation of Little Ice Age climate in the tropical Andes, Proc. Natl. Acad. Sci. U.S.A., 103, 8937-8942, doi:10.1073/pnas.0603118103.
66. Powers, L. A., T. C. Johnson, J. P. Werne, I. S. Castañeda, E. C. Hopmans, J. S. Sinninghe Damsté, and S. Schouten (2005), Large temperature variability in the southern African tropics since the Last Glacial Maximum, Geophys. Res. Lett., 32, L08706, doi:10.1029/ 2004GL022014.
67. Renssen, H., H. Goosse, T. Fichefet, and J.-M. Campin (2001), The 8.2 kyr BP event simulated by a global atmosphere-sea-ice-ocean model, Geophys. Res. Lett., 28,1567-1570, doi:10.1029/2000GL012602.
68. Renssen, H., H. Goosse, and T. Fichefet (2002), Modeling the effect of freshwater pulses on the early Holocene climate: The influence of high-frequency climate variability, Paleoceanography, 17(2), 1020, doi: 10.1029/2001PA000649.
69. Rosell-Melé, A., E. Bard, K.-C. Emeis, B. Grieger, C. Hewitt, P. J. Müller, and R. R. Schneider (2004), Sea surface temperature anomalies in the oceans at the LGM estimated from the alkenone-U37K′ index: Comparison with GCMs, Geophys. Res. Lett., 31, L03208, doi:10.1029/2003GL018151.
70. Russell, J. M., and T. C. Johnson (2007), Little Ice Age drought in equatorial Africa: Intertropical Convergence Zone migrations and El Nino-Southern Oscillation variability, Geology, 35, 21-24, doi:10.1130/G23125A.1.
71. Russell, J., M. R. Talbot, and B. J. Haskell (2003), Mid-Holocene climate change in Lake Bosumtwi, Ghana, Quat. Res., 60, 133-141, doi:10.1016/S0033-5894 (03)00065-6.
72. Schiller, A., U. Mikolajewicz, and R. Voss (1997), The stability of the North Atlantic thermohaline circulation in a coupled ocean-atmosphere general circulation model, Clim. Dyn., 13, 325-347, doi:10.1007/ s003820050169.
73. Schmitt, D. R., B. Milkereit, T. Karp, C. Scholz, S. Danour, D. Meilleux, and M. Welz (2006), In situ seismic measurements in borehole LB-08A in the Bosumtwi impact structure, Ghana: Preliminary interpretation, Meteorit. Planet. Sci., 42, 755-768.
74. Scholz, C. A., et al. (2007), East African megadroughts between 135 and 75 thousand years ago and bearing on early-modern human origins, Proc. Natl. Acad. Sci. U.S.A., 104(42), 16,416-16,421, doi:10.1073/pnas.0703874104.
75. Shanahan, T. M., J. T. Overpeck, C. W. Wheeler, J. W. Beek, J. S. Pigati, M. R. Talbot, C. A. Scholz, J. Peck, and J. W. King (2006), Paleoclimatic variations in West Africa from a record of late Pleistocene and Holocene lake level stands of Lake Bosumtwi, Ghana, Palaeogeogr. Palaeoclimatol. Palaeoecol., 242, 287-302, doi:10.1016/j.palaeo.2006.06.007.
76. Shanahan, T. M., J. T. Overpeck, C. Sholz, E. Sharpe, and J. Arko (2007), Simulating the response of a closed basin lake to recent climate changes in tropical West Africa (Lake Bosumtwi, Ghana), Hydrol. Processes, 21, 1678-1691, doi:10.1002/hyp.6359.
77. Shanahan, T. M., J. T. Overpeck, C. W. Wheeler, J. W. Beck, J. A. Peck, J. W. King, and C. Scholz (2008), The formation of biogeochemical laminations in Lake Bosumtwi, Ghana and their usefulness as indicators of past environmental changes, J. Paleolimnol., doi:10.1007/ sl0933-0079164-4, in press.
78. Shin, S.-I., Z. Liu, B. Otto-Bliesner, E. C. Brady, J. E. Kutzbach, and S. P. Harrison (2003), A simulation of the Last Glacial Maximum climate using the NCAR-CCSM, Clim. Dyn., 20, 127-151.
79. Shindell, D. T., G. A. Schmidt, M. E. Mann, D. Rind, and A. Waple (2001), Solar forcing of regional climate change during the Maunder Minimum, Science, 294, 2149-2152, doi:10.1126/science.1064363.
80. Shindell, D. T., G. Faluvegi, R. L. Miller, G. A. Schmidt, J. E. Hansen, and S. Sun (2006), Solar and anthropogenic forcing of tropical hydrology, Geophys. Res. Lett., 33, L24706, doi:10.1029/ 2006GL027468.
81. Stouffer, R. J., et al. (2006), Investigating the causes of the response of the Thermohaline Circulation to past and future climate changes, J. Clim., 19, 1365-1387, doi:10.1175/JCLI3689.1.
82. Street, F. A. (1979), Late Quaternary precipitation estimates for the Ziway-Shala basin, southern Ethiopia, Palaeoecol. Africa, 10/11, 135-143.
83. Street, F. A., and A. T. Grove (1979), Global maps of lake-level fluctuations since 30,000 yr B.P, Quat. Res., 12, 83-118, doi:10.1016/00335894(79)90092-9.
84. Street-Perrott, F. A. and S. A. Harrison (1984), Temporal variations in lake levels since 30,000 yr BP-An index of the global hydrological cycle, in Climate Processes and Climate Sensitivity, Geophys. Monogr Ser., vol. 29, edited by J. E. Hansen and T. Takahashi; pp. 118-129, AGU, Washington, D. C.
85. Street-Perrott, F. A., and R. A. Perrott (1990), Abrupt climate fluctuations in the tropics: the influence of Atlantic Ocean circulation, Nature, 343, 607-612, doi:10.1038/343607a0.
86. Stuiver, M., P. J. Reimer, E. Bard, J. W. Beck, G. S. Burr, K. A. Hughen, B. Kromer, G. McCormac, J. Van der Plicht, and M. Spurk (1998), INTCAL98 radiocarbon age calibration, 24,000-0 cal BP, Radiocarbon, 40, 1041-1083.
87. Stute, M., and A. S. Talma (1998), Glacial temperatures and moisture transport regimes reconstructed from noble gases and delta 18O, Stampriet aquifer, Namibia, in Isotope Techniques in the Study of Environmental Change, pp. 307-318, Int. At. Energy Agency, Vienna.
88. Su, H., and J. D. Neelin (2005), Dynamical mechanisms for African monsoon changes during the Holocene, J. Geophys. Res., 110, D19105, doi:10.1029/2005JD005806.
89. Swain, A. M., J. E. Kutzbach, and S. Hastenrath (1983), Estimates of Holocene precipitation for Rajasthan, India, based on pollen and lake-level data, Quat. Res., 19, 1-17.
90. Talbot, M. R., and G. Delibrias (1977), Holocene variations in the level of Lake Bosumtwi, Ghana, Nature, 268, 722-724, doi:10.1038/ 268722a0.
91. Talbot, M. R., and G. Delibrias (1980), A new late-Holocene water-level curve for Lake Bosumtwi, Ghana, Earth Planet. Sci. Lett., 47, 336-344, doi:10.1016/0012-821X(80)90020-5.
92. Talbot, M. R., and T. Johannessen (1992), A high resolution paleoclimatic record for the last 27,000 years in tropical West Africa from the carbon and nitrogen isotopic composition of lacustrine organic matter, Earth Planet. Sci. Lett., 110, 23-37, doi:10.1016/ 0012-821X(92)90036-U.
93. Trauth, M. H., A. L. Deino, A. G. N. Bergner, and M. R. Strecker (2003), East African climate change and orbital forcing during the last 175 kyr BP, Earth Planet. Sci. Lett., 206, 297-313, doi:10.1016/ SO012-821X(02)01105-6.
94. Turner, B. F., L. R. Gardner, and W. E. Sharp (1996), The hydrology of Lake Bosumtwi, a climate-sensitive lake in Ghana, West Africa, J. Hydrol., 183, 243-261, doi:10.1016/0022-1694(95)02982-6.
95. Vellinga, M., and R. A. Wood (2002), Global climatic impacts of a collapse of the Atlantic thermohaline circulation, Clim. Change, 54, 251-267, doi:10.1023/A:1016168827653.
96. Verschuren, D., K. Laird, and B. Cumming (2000), Rainfall and drought in equatorial east Africa during the past 1,100 years, Nature, 403, 410-414, doi:10.1038/35000179.
97. Vincens, A., F. Chalie, R. Bonnefille, J. Guilot, and J.-J. Tiercelin (1993), Pollen-derived rainfall and temperature estimates from Lake Tanganyika and their implication for the Late Pleistocene water levels, Quat. Res., 40, 343-350.
98. Vincent, C. E., T. D. Davies, P. Brimblecombe, and A. K. C. Beresford (1989), Lake levels and glaciers: Indicators of the changing rainfall in the mountains of East Africa, in Quaternary and Environmental Research on East African Mountains, edited by W. C. Maheny, pp. 199-216, A.A. Balkema, Rotterdam, Netherlands.
99. Vizy, E. K., and K. H. Cook (2001), Mechanisms by which Gulf of Guinea and eastern North Atlantic sea surface temperature anomalies can influence African rainfall, J. Clim., 14, 795-821, doi:10.1175/ 1520-0442(2001)014<0795:MBWGOG>2.0.CO;2.
100. Wagner, R. G., and A. M. da Silva (1994), Surface conditions associated with anomalous rainfall in the Guinea coastal region, Int. J. Climatol., 14, 179-199, doi:10.1002/joc.3370140205.
101. Watanabe, T., A. Winter, and T. Oba (2001), Seasonal changes in sea surface temperature and salinity during the Little Ice Age in the Caribbean Sea deduced from Mg/Ca and 18O/16O ratios in coals, Mar. Geol., 173, 21-35, doi:10.1016/S0025-3227(00)00166-3.
102. Ward, M. N. (1998), Diagnosis and short-lead time prediction of summer rainfall in tropical North Africa at interannual and decadal time-scales, J. Clim., 11, 3167-3191, doi:10.1175/ 1520-0442(1998)011<3167:DASLTP>2.0.CO;2.
103. Wickens, G. E. (1975), Changes in the climate and vegetation of the Sudan since 20,000 B.P, Boissiera, 24, 43-65.
104. Winter, A., H. Ishioroshi, T. Watanabe, and T. Oba (2000), Caribbean sea surface temperatures: two-to-three degrees colder than present during the Little Ice Age, Geophys. Res. Lett., 27, 3365-3368, doi:10.1029/2000GL011426.
105. Yin, X., and S. E. Nicholson (1998), The water balance of Lake Victoria, Hydrol. Sci. J., 43, 789-811.
106. Zhang, R., and T. L. Delworth (2005), Simulated tropical response to a substantial weakening of the Atlantic thermohaline circulation, J. Clim., 18, 1853-1860, doi:10.1175/JCLI3460.1.
107. Zhao, M. X., G. Eglinton, S. K. Haslett, R. W. Jordan, M. Samthein, and Z. H. Zhang (2000), Marine and terrestrial biomarker records for the last 35,000 years at ODP site 658C off NW Africa, Org. Geochem., 31, 919-930.
108. Zhao, Y., P. Braconnot, O. Marti, S. P. Harrison, C. Hewitt, A. Kitoh, Z. Liu, U. Mikolajewicz, B. Otto-Bliesner, and S. L. Weber (2005), A multi-model analysis of the role of the ocean on the African and Indian monsoon during the Holocene, Clim. Dyn., 25, 777-800, doi:10.1007/ s00382-005-0075-7.