Midterm Colloquium by Anne Wang Petersen – Niels Bohr Institute - University of Copenhagen

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Midterm Colloquium by Anne Wang Petersen

Response of stable water isotopes in Greenland precipitation to varying Eemian ice sheet configurations - a general circulation model study

Peter Langen, Jesper Sjolte (Bo Vinther)

The climate of the previous interglacial, the Eemian, was quite similar to the present. Temerature records show that the global temperature of the warmest period during the Eemian was 3-5°C warmer, than what we presently observe. Therefore the Eemian period is comparable to the expected climate of the following century with estimated global mean temperature changes of 2-4°C.

On the basis of climate models and geological sea level traces the Eemian global sea level is known to have been approximately 5 m higher than present. In accordance to this, it is interesting to investigate the extent and height of the Greenland ice sheet during the Eemian, since it can be used to estimate the Arctic contribution to sea level changes during the Eemian period. Moreover, it will give an idea of how the Greenland ice sheet may change during the following century.

With the use of an atmospheric global circulation model (CAM) the spatial isotopic composition of the precipitation on the Greenland Ice Sheet will be investigated with different Eemian ice sheet configurations. The response of the isotopic composition will be compared to and discussed on the basis of existing isotope measurements from the Eemian period, as well as the present day composition associated with the existing ice sheet and prevailing conditions.

Thus this project will focus on the effect of the ice sheet configuration on the isotopes with the aim of allowing for investigations of the extent of the Greenland Ice Sheet in the Eemian period on the basis of isotopic composition.

During this midway-evaluation the work that have been done will be presented as well as the further plans for the thesis.