Modelling Glaciers in the HARMONIE-AROME NWP model
HARMONIE-AROME is a convection-permitting non-hydrostatic model that includes the multi-purpose SURFEX surface model. It is developed for high resolution (1–3 km) weather forecasting and applied in a number of regions in Europe and the Mediterranean. A version of HARMONIE-AROME is also under deve...
Main Authors: | , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2017-12-01
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Series: | Advances in Science and Research |
Online Access: | https://www.adv-sci-res.net/14/323/2017/asr-14-323-2017.pdf |
Summary: | HARMONIE-AROME is a convection-permitting non-hydrostatic model that includes
the multi-purpose SURFEX surface model. It is developed for high resolution
(1–3 km) weather forecasting and applied in a number of regions in Europe and
the Mediterranean. A version of HARMONIE-AROME is also under development for regional climate modelling.
Here we run HARMONIE-AROME for a domain over
Greenland that includes a significant portion of the Greenland ice sheet. The
model output reproduces temperature, wind speed and direction and relative
humidity over the ice sheet well when compared with the observations from
PROMICE automatic weather stations (AWS) operated within the model domain on
the ice sheet (mean temperature bias 1.31 ± 3.6 K) but we identified
a much lower bias (−0.16 ± 2.3 K) at PROMICE sites on days where melt
does not occur at the ice sheet surface and is thus an artefact of the
simplified surface scheme over glaciers in the existing HARMONIE-AROME
operational set-up. The bias in summer time temperature also affects wind
speed and direction as the dominant katabatic winds are caused by the cold
ice surface and slope gradient. By setting an upper threshold to the surface
temperature of the ice surface within SURFEX we show that the weather
forecast error over the Greenland ice sheet can be reduced in summer when
glacier ice is exposed. This improvement will facilitate accurate ice melt
and run-off computations, important both for ice surface mass budget
estimation and for commercial applications such as hydro-power forecasting.
Furthermore, the HCLIM regional climate model derived from HARMONIE-AROME
will need to accurately account for glacier surface processes in these
regions in order to be used to accurately compute the surface mass budget of
ice sheets and glaciers, a key goal of regional climate modelling studies in
Greenland. |
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ISSN: | 1992-0628 1992-0636 |