Lake Bosumtwi, Ghana 21,000 Year Leaf Wax Hydrogen Isotope Data Shanahan, T.M.; McKay, N.P.; Hughen, K.A.; Overpeck, J.T.; Otto-Bliesner, B.L.; Heil, C.W.; King, J.W.; Scholz, C.A.; Peck, J.A. Shanahan, T.M. McKay, N.P. Hughen, K.A. Overpeck, J.T. Otto-Bliesner, B.L. Heil, C.W. King, J.W. Scholz, C.A. Peck, J.A. Monsoon earth science/paleoclimate/paleolimnology (delta 13C,C31 n-alkane,null,per mil PDB,null,paleolimnology,null,isotope ratio mass spectrometry,N,null) earth science/paleoclimate/paleolimnology (delta 2H,C31 n-alkane,null,per mil VSMOW,null,paleolimnology,corrected,isotope ratio mass spectrometry,N,ice-volume corrected) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Lake Bosumtwi>LATITUDE 6.5>LONGITUDE -1.4167) During the African Humid Period about 14,800 to 5,500 years ago, changes in incoming solar radiation during Northern Hemisphere summers led to the large-scale expansion and subsequent collapse of the African monsoon. Hydrologic reconstructions from arid North Africa show an abrupt onset and termination of the African Humid Period. These abrupt transitions have been invoked in arguments that the African monsoon responds rapidly to gradual forcing as a result of nonlinear land surface feedbacks. Here we present a reconstruction of precipitation in humid tropical West Africa for the past 20,000 years using the hydrogen isotope composition of leaf waxes preserved in sediments from Lake Bosumtwi, Ghana. We show that over much of tropical and subtropical Africa the monsoon responded synchronously and predictably to glacial reorganizations of overturning circulation in the Atlantic Ocean, but the response to the relatively weaker radiative forcing during the African Humid Period was more spatially and temporally complex. A synthesis of hydrologic reconstructions from across Africa shows that the termination of the African Humid Period was locally abrupt, but occurred progressively later at lower latitudes. We propose that this time-transgressive termination of the African Humid Period reflects declining rainfall intensity induced directly by decreasing summer insolation as well as the gradual southward migration of the tropical rainbelt that occurred during this interval. STUDY NOTES: Hydrogen (dD) and carbon (d13C) isotope data from leaf waxes in sediments collected in Lake Bosumtwi, Ghana, covering the past 21,000 years. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Shanahan, T.M. Investigator : McKay, N.P. Investigator : Hughen, K.A. Investigator : Overpeck, J.T. Investigator : Otto-Bliesner, B.L. Investigator : Heil, C.W. Investigator : King, J.W. Investigator : Scholz, C.A. Investigator : Peck, J.A. 2015-04-08 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/18355 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2015dd.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2015dd.txt English https://www.ncdc.noaa.gov/paleo/study/18355 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2015dd.txt Timothy M. Shanahan, Nicholas P. McKay, Konrad A. Hughen, Jonathan T. Overpeck, Bette Otto-Bliesner, Clifford W. Heil, John King, Christopher A. Scholz, John Peck2015The time-transgressive termination of the African Humid PeriodNature Geoscience82140-14410.1038/ngeo2329http://www.nature.com/ngeo/journal/v8/n2/abs/ngeo2329.html START YEAR: 21025 cal yr BP * END YEAR: 68 cal yr BP -1.4167 6.5 -1.4167 6.5