Layering of surface snow and firn at Kohnen Station, Antarctica - noise or seasonal signal?


Contact
Thomas.Laepple [ at ] awi.de

Abstract

The density of firn is an important property for monitoring and modeling the ice sheet as well as to model the pore close-off and thus to interpret ice core-based greenhouse gas records. One feature, which is still in debate, is the potential existence of an annual cycle of firn density in low-accumulation regions. Several studies describe or assume seasonally successive density layers, horizontally evenly distributed, as seen in radar data. On the other hand, high-resolution density measurements on firn cores in Antarctica and Greenland showed no clear seasonal cycle in the top few meters. A major caveat of most existing snow-pit and firn-core based studies is that they represent one vertical profile from a laterally heterogeneous density field. To overcome this, we created an extensive dataset of horizontal and vertical density data at Kohnen Station, Dronning Maud Land on the East Antarctic Plateau. We drilled and analyzed three 90 m long firn cores as well as 160 one meter long vertical profiles from two elongated snow trenches to obtain a two dimensional view of the density variations. The analysis of the 45 m wide and 1 m deep density fields reveals a seasonal cycle in density. However, the seasonality is overprinted by strong stratigraphic noise, making it invisible when analyzing single firn cores. Our density dataset extends the view from the local ice-core perspective to a hundred meter scale and thus supports linking spatially integrating methods such as radar and seismic studies to ice and firn cores.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Publication Status
Published
Eprint ID
41912
DOI 10.1002/2016JF003919

Cite as
Laepple, T. , Hörhold, M. , Münch, T. , Freitag, J. , Wegner, A. and Kipfstuhl, S. (2016): Layering of surface snow and firn at Kohnen Station, Antarctica - noise or seasonal signal? , Journal of Geophysical Research: Earth Surface, 121 , pp. 1849-1860 . doi: 10.1002/2016JF003919


Download
[thumbnail of Laepple_et_al-2016-Journal_of_Geophysical_Research__Earth_Surface.pdf]
Preview
PDF
Laepple_et_al-2016-Journal_of_Geophysical_Research__Earth_Surface.pdf

Download (846kB) | Preview
Cite this document as:

Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Citation

Geographical region

Research Platforms

Campaigns
N/A


Actions
Edit Item Edit Item