The magnitude of precipitation/evaporation changes in the Naivasha Basin (Kenya) during the last 150 kyr
by
Andreas G.N. Bergner
Institut fuer Geowissenschaften, Universitaet Potsdam, Germany
Coauthors: M.H. Trauth, B. Bookhagen

We modeled the two most extreme lake phases of Lake Naivasha at 138 and 9 kyr BP in order to compare the paleoclimatic conditions during these times with modern climate. First, the paleo-lakes were reconstructed from surface outcrops of lacustrine deposits and sediment cores. Second, we modeled the hydrological conditions that caused the reconstructed lakes starting from the present-day situation. Our results show that the character of the paleo-lakes and the modeled climatic scenarios were similar at 138 and 9 kyr BP, but significantly different from today. The most important difference is a ~15% increase in precipitation from the modern value. The modeled amount of rainfall is even higher (around +30%) if the model allows a significant vegetation feedback, i.e., a change in vegetation due to the increase humidity in the catchment. The most likely cause for a wetter climate at 138 and 9 kyr is a more intense intertropical convergence in East Africa and hence higher moisture levels.

Date received: March 30, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cagc-82.