NOAA-OGP NA03OAR4310046
2003-2006

P.I.: M. Vuille
Co-P.I.: R. S. Bradley

    We propose to study climate and stable isotope (d18O and dD) variability over the East African – Arabian domain, where important paleoclimatic records based on stable isotopes (e.g. speleothems, ice cores) have been recovered recently. These records provide important information about the past history of the Indian Ocean Monsoon system, but their interpretation is still a heavily debated issue. We will use the GISS II Atmospheric General Circulation Model with incorporated stable isotopic tracers and simulate climate and stable isotope variability for modern, mid-Holocene (6ky B.P.) and LGM (21ky B.P.) conditions.
Results from our model experiments will be compared with the available paleorecords and complemented and verified by observational analysis including NCEP/NCAR reanalysis and IAEA-GNIP data. We further intend to study the influence of moisture source variability and transport history of air masses on the stable isotopic composition of the Kilimanjaro ice core by performing trajectory analysis during snowfall events detected by our Automated weather station at the drill site. Over the past few years we have successfully pursued a similar strategy, combining model and observational analysis, to gain a better understanding of stable isotope variability in Andean ice cores.
Our proposed project directly addresses several key issues of the current paleoclimate research agenda. In particular the proposed research will aid in calibrating and validating existing paleoclimatic data sets; document the quantitative character of observed climate variations and changes; and attribute changes in the observed climate record to specific climate forcings.