EGU2020-8728
https://doi.org/10.5194/egusphere-egu2020-8728
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The representation of Föhn events to the east of the Antarctic Peninsula in simulations by the Antarctic Mesoscale Prediction System (AMPS)

Amélie Kirchgaessner1, John King1, and Alan Gadian2
Amélie Kirchgaessner et al.
  • 1British Antarctic Survey, Atmosphere, Ice and Climate Team, Cambridge, United Kingdom of Great Britain and Northern Ireland (acrki@bas.ac.uk)
  • 2School of Earth and Environment, University of Leeds, Leeds, United Kingdom of Great Britain and Northern Ireland

We examine the representation of Föhn events across the Antarctic Peninsula Mountains during 2011 as they were observed in measurements by an Automatic Weather Station, and in simulations with the Weather Research and Forecasting Model (WRF) as run for the Antarctic Mesoscale Prediction System (AMPS). On the Larsen Ice Shelf (LIS) in the lee of this mountain range Föhn winds are thought to provide the atmospheric conditions for significant warming over the ice shelf thus leading to the initial firn densification and subsequently providing the melt water for hydrofracturing. This process has led to the dramatic collapse of huge parts of the LIS in 1995 and 2002 respectively.

We find that, while the model generally simulates meteorological parameters very well, and shows good skills in capturing the occurrence, frequency and duration of Föhn events realistically, it underestimates the temperature increase and the humidity decrease during the Föhn significantly, and may thus underestimate the contribution of Föhn to driving surface melt on the LIS. Our results indicate that the misrepresentation of cloud properties and particularly the absence of mixed phase clouds in AMPS, affects the quality of weather simulation under normal conditions to some extent, and to a larger extent the model’s capability to simulate the strength of Föhn conditions - and thus their contribution to driving surface melt on the LIS - adequately.

How to cite: Kirchgaessner, A., King, J., and Gadian, A.: The representation of Föhn events to the east of the Antarctic Peninsula in simulations by the Antarctic Mesoscale Prediction System (AMPS), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8728, https://doi.org/10.5194/egusphere-egu2020-8728, 2020

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