Steffen Konrad

Surface Climate of the Greenland Ice Sheet and the Assessment of Accumulation Variability and Change: the Greenland Climate Network (GC-Net)

Project Number: NNX11AF47G
Project Type:
Project Duration: 01/01/2017 - 12/31/2020
Funding Source: USNSF, NAS ,
Project Leader: Prof. Konrad Steffen
Direktor
WSL
Z├╝rcherstrasse 111
8903 Birmensdorf
Phone: +41 (0) 44 739 24 55 ; +41 (0) 44 739 21 11
FAX: +41 (0) 44 739 25 75
e-Mail: konrad.steffen(at)wsl.ch
http://cires.colorado.edu

related to this project.


Research Areas:
Antarctic
Arctic
High Altitude

Keywords:
Greenland, climate, mass balance, surface melt, sea level change

Abstract:
The Arctic climate has experienced some major changes in the past decades. Natural climate variability is organized into spatial patterns of high and low pressure regions, the Arctic Oscillation, and the North Pacific patterns. When either of the patterns is in its positive extreme, the pattern contributes to an overall Arctic warm period. In recent years (2000 to present), the pattern of warm temperature anomalies is circumpolar in distribution and dominates the Polar Regions.The annual mean air temperature was found to be 4 ┬║C warmer along the western slope of the ice sheet as compared to the standard decade 1951?1960. Also, the Greenland cumulative wet snow area increased on average by 40% since 1979 based on passive microwave satellite data. With the increased surface melt, the snow and firn layers increase in density due to the percolation and refreezing of melt water, hence reducing the surface height by near-surface snow densification.
Observations from satellites and aircraft since 1990 show substantial ice loss from Greenland that has doubled in the last decade, both from increased runoff (melt) and from acceleration of glaciers (ice dynamics) draining the ice sheet. Monitoring of these processes are essential to improve our understanding of the ice sheet mass balance, and estimates of the rate and timing of 21st-century and longer-term sea level projections. Therefore, ground-based process studies are required for the interpretation of satellite-derived ice sheet parameters currently used in modelling the response of the Arctic in a warming climate.
We propose to maintain a climate network of 16 automatic stations on the Greenland ice sheet to extend the climate record which started in 1995. The continuation of this climate record is crucial for understanding the decadal climate variability and to capture the recent Arctic warm phase. Further, the climate parameters are widely used for process studies by the polar research community, and for model validations and verification. The GC-Net data are the only climatological measurements covering all major climatic zones of the ice sheet for a duration of 20 years.
We propose to install multi-frequency radars at two locations on the ice sheet to monitor the accumulation and melt at the resolution of individual snow layers (storm event) in the firn. The upward-looking radar systems is capable of monitoring depths of melt percolation and can quantify the amount of liquid water remaining in the snowpack which is essential for the interpretation of satellite data such as altimeter, passive microwave, or radar.
We propose to collect a comprehensive dataset consisting of high-resolution snow profiles at each GC-Net location on the ice sheet. This study will link snow physics with snow cover modeling through the measurements of high-resolution snow microstructure parameters. The snowpack and its mechanical and structural properties are important to improve firn densification and mass-balance models as well as larger scale climatological models (e.g. RACMO, MAR).
These objectives are consistent with the research priorities of the NASA Science Plan 2014 (Earth Science) /to improve the ability to predict climate changes by better understanding the roles and interactions of the ocean, atmosphere, land and ice in the climate system/, and NASA?s Strategic Goal 2.1 /to advance Earth system science to meet the challenges of climate and environmental change/. Further, it meets NASA?s strategic objective /to explore the interaction among the atmosphere, oceans, ice sheets, land surface interior, and life itself/, and to inform decision makers about possible impacts.


Last update: 4/28/17
Source of data: ProClim- Research InfoSystem (1993-2018)
Update the data of project: CH-6038

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