Atmospheric Controls on Stable Isotopes in Antarctica (ACOSIA)
Aim of the study
The FWF-funded project ACOSIA (P-28695) aims at a better understanding of the processes that influence the stable isotopes of snow and ice in Antarctica between precipitation events. Studies in Greenland showed that there are considerable changes of the isotopic composition of the snowpack, following changes in atmospheric variables, even when no precipitation is observed. This includes a daily cycle as well as changes on synoptic time scales, i.e. due to advection of different air masses. Progress in measuring stable isotope ratios, namely the introduction of portable laser spectrometers, made it possible to not only determine stable isotopes of snow in the field, but also to continuously measure the stable isotope ratios of water vapor. At the German Antarctic wintering base Neumayer III in coastal Dronning Maud Land such measurements have been carried out since the end of Austral summer of 2016/17. Neumayer is also a fully equipped meteorological station, which includes SYNOP observations, a meteorological measuring mast and radiosonde data. This abundance of data can be related to the stable isotope data and used to study the processes influencing the isotope ratios. Additionally, a 37-year time series of stable isotopes from fresh snow samples is available to put the findings into a longer temporal perspective. The results of the study will help to derive more exact paleotemperatures from the deep ice cores in Antarctica.
The project is carried out in close cooperation with:
Alfred-Wegener-Institute Helmholtz Center of Polar and Marine Research (AWI), Germany
(Martin Werner, Saeid Bagheri, Maria Hoerhold)
National Center for Atmospheric Research (NCAR), Boulder, CO, USA
(Jordan G. Powers, Kevin W. Manning)
Laboratoire des Sciences de l’Environnement et du Climat (LSCE), France
(Valerie Masson, Amaelle Landais)
University of Bergen, Norway
(Hans Christian Steen-Larsen)
Antarctic field season 2017/18
In Austral summer 2017/18, field work was carried out at Neumayer III between early December 2017 and end of February 2018. Since the measurements with the laser spectrometer, which had been originally planned in the project, are being carried out by AWI on a routine base meanwhile, a comprehensive snow sampling program was carried out, which included a so-called surface transect, i.e. daily sampling of snow from the surface and at 6-7 cm depth along a profile marked by 11 bamboo poles with 100m distance between the poles. A shorter transect, marked by poles every 10 meter, was sampled for so-called SSA (specific surface area) measurements. Additionally, 25cm and 1m-deep samples were taken occasionally at some of the surface transect locations. This work was carried out by Elisabeth Schlosser (PI) and Saeid Bagheri. All samples were analysed in the lab by Maria Hoerhold at AWI and stable isotope ratios were determined.
to be continued
to be continued