The University of Southampton
University of Southampton Institutional Repository

Micrometeorological and morphological observations of surface hoar dynamics on a mountain snow cover

Stossel, F., Guala, M., Fierz, C., Manes, C. and Lehning, M. (2010) Micrometeorological and morphological observations of surface hoar dynamics on a mountain snow cover Water Resources Research, 46, (4), W04511-[11pp}. (doi:10.1029/2009WR008198).

Record type: Article

Abstract

The formation, growth, and destruction of surface hoar crystals is an important feature of mountain snow covers as buried surface hoar layers are a frequent weak layer leading to unstable snowpacks. The energy and mass exchange associated with surface hoar dynamics is further an important part of land-atmosphere interaction over snow. A quantitative prediction of surface hoar evolution based on local environmental conditions is, however, difficult. We carried out measurements of crystal hoar size and total surface mass changes in the period between January and March 2007 on the Weissfluhjoch study plot of the WSL Institute for Snow and Avalanche Research SLF, located above Davos, Switzerland, at 2540 m above sea level. For the first time, a direct comparison between eddy correlation measurements of latent heat flux and lysimeter-like measurements of surface mass change has been made. Results show that the growth of surface hoar crystals is very well correlated with deposition of water vapor during clear-sky nights as measured by two eddy correlation systems placed close to the ground. By analyzing local meteorological data, we confirm that low to moderate wind speed, humid air, and clear-sky nights are the necessary ingredients for the occurrence of significant vapor fluxes toward the surface and thus for the growth of surface hoar. We also confirm that surface hoar crystals tend to preserve during daytime, when strong sublimation occurs, although their size significantly reduces. Despite the complexities associated with mountain terrain and snow surfaces, such as nonequilibrium boundary layers and stratification effects, the hoar formation could be predicted by the snow cover model SNOWPACK, which uses a bulk Monin-Obukhov (MO) parameterization for the turbulent heat fluxes. On the basis of the comparison between direct observations and model predictions, we suggest that neutral stability conditions in the MO formulation provide the most stable and least flawed prediction for surface hoar formation

PDF Stossel_et_al_2010.pdf - Version of Record
Download (0B)

More information

Published date: 24 April 2010
Organisations: Energy & Climate Change Group

Identifiers

Local EPrints ID: 204115
URI: http://eprints.soton.ac.uk/id/eprint/204115
ISSN: 0043-1397
PURE UUID: c7808cd6-ad1f-42a7-8d51-fadc5907135b

Catalogue record

Date deposited: 24 Nov 2011 12:23
Last modified: 18 Jul 2017 11:07

Export record

Altmetrics

Contributors

Author: F. Stossel
Author: M. Guala
Author: C. Fierz
Author: C. Manes
Author: M. Lehning

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×