Reconstruction of climate history from polar ice sheets
Human activities will have serious impact on the global environmental system and will change the earths climate in the future. To predict the climate change of the earth reliable, the knowledge of the climate of the past and the forcing mechanisms of natural climate variability is essential.
Polar ice sheets of the Arctic and Antarctica are unique climate archives, preserving the climate of the past in high temporal resolution back to 800 000 years and possibly beyond. Ice core analysis gives access to a wide range of atmospheric and climatic parameters such as temperature, precipitation, trace gases, aerosols and mineral dust which are essential for the reconstruction of the paleoclimate.
Paleoclimate research at the glaciology department of AWI:
One of the main fields of research of the AWI glaciology department concerns the reconstruction of paleotemperature, snow accumulation (precipitation) and the concentration of atmospheric aerosols and mineral dust as well as their temporal and spatial variability on the Greenland and Antarctic ice sheets.
The stable water isotopes (18O and D) in precipitation are the basis for the reconstruction of paleotemperature due to the empirical linear relationship between mean annual air temperature and the mean isotopic composition of the deposited snow.
Investigations of annual snow accumulation provide information about changes in precipitation rates in the past and their correlation with changes in the atmospheric circulation pattern. Furthermore the accumulation data will be used as one of the essential input data for calculating the surface mass balance of the ice sheets.
Methane synchronization of the EDML and the NGRIP records reveals a one-toone assignment of each Antarctic warming with a corresponding stadial in Greenland. Displayed are 100-yr averages during MIS3 in the EDML, EDC26 and Byrd1 ice core for the time interval 10–60 kyr BP in comparison with the NGRIP d18O record from Northern Greenland9. All records are CH4 synchronized and given on the new GICC05 age scale for the NGRIP ice core, which has been derived by counting annual layers down to 41 kyr and by a flow model for older ages9,21. Yellow bars indicate the Greenland stadial periods that we relate to respective Antarctic temperature increases. The approximate timing of Heinrich layers in North Atlantic sediments is indicated as well27. The y axis on the right side indicates approximate temperature changes at EDML based on the modern spatial gradient between d18O and temperature. Nature, 444, 195-198., doi:10.1038/nature05301
