NOAA/WDS Paleoclimatology - Global Lake-Level Variations from 18,000 to 0 Years Ago: A Paleoclimatic Analysis

Fluctuations in the water levels of lakes are an important source of information about past climates, and can be used to validate paleoclimatic simulations made with atmospheric general-circulation models. The Oxford Lake-Level Data bank contains information about variations in the water levels of approximately 360 lake basins during the last 30,000 years. This data set was compiled as part of COHMAP (the Climates of the Holocene Mapping Project). In this report, regional and global maps of lake status (coded as high, intermediate or low) at 18, 15, 12, 9, 6, 3, and 0 thousand years before Present are presented and compared with numerical simulations for the same time slices carried out with NCAR Community Climate Model. Although agreement between the data and the model is generally excellent, significant discrepancies occur. These may reflect the effects of changes in boundary conditions that were not included in the experiments, for example increases glacial-age aerosol loadings, as well as the inability of the model to portray some of the complexities of the climate system such as oceanic circulation and orographic effects.