Impact of Extreme Land Surface Heterogeneity on Micrometeorology over Spring Snow Cover

Impact of Extreme Land Surface Heterogeneity on Micrometeorology over Spring Snow Cover AbstractThe melting mountain snow cover in spring typically changes from a continuous snow cover to a mosaic of patches of snow and bare ground, inducing an extreme heterogeneity of the land surface. A comprehensive measurement campaign, the Dischma experiment, was conducted during three entire ablation seasons. The aim of this study was to experimentally investigate the small-scale boundary layer dynamics over a melting snow cover with a gradually decreasing snow cover fraction and the associated heat exchange at the snow surface. This study presents a unique dataset combining eddy covariance measurements at different atmospheric levels with maps of snow surface temperatures and snow cover fractions. The experiments evidence diurnal mountain wind systems driving the diurnal cycle of turbulent sensible heat fluxes over snow and the formation of katabatic flows over long-lasting snow patches strongly affecting the temporal evolution of snow surface temperature patterns. The snow cover distribution is also shown to be of vital importance for the frequency of stable internal boundary layer development over snow. For situations with a clear evidence of stable internal boundary layer development over snow, the data reveal a very shallow atmospheric layer adjacent to the snow cover decoupled from the warm-air advection above. These measurements confirm previous wind tunnel experiments that also evidenced a decoupling of the air adjacent to the snow cover from the warmer air above, especially within topographical depressions and when ambient wind velocities are low. For these situations, in particular, all tested energy balance models strongly overestimated the turbulent sensible heat flux directed toward the snow cover. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Hydrometeorology American Meteorological Society

Impact of Extreme Land Surface Heterogeneity on Micrometeorology over Spring Snow Cover

Loading next page...
 
/lp/ams/impact-of-extreme-land-surface-heterogeneity-on-micrometeorology-over-vx3jEd5uxq
Publisher
American Meteorological Society
Copyright
Copyright © American Meteorological Society
ISSN
1525-7541
D.O.I.
10.1175/JHM-D-17-0074.1
Publisher site
See Article on Publisher Site

Abstract

AbstractThe melting mountain snow cover in spring typically changes from a continuous snow cover to a mosaic of patches of snow and bare ground, inducing an extreme heterogeneity of the land surface. A comprehensive measurement campaign, the Dischma experiment, was conducted during three entire ablation seasons. The aim of this study was to experimentally investigate the small-scale boundary layer dynamics over a melting snow cover with a gradually decreasing snow cover fraction and the associated heat exchange at the snow surface. This study presents a unique dataset combining eddy covariance measurements at different atmospheric levels with maps of snow surface temperatures and snow cover fractions. The experiments evidence diurnal mountain wind systems driving the diurnal cycle of turbulent sensible heat fluxes over snow and the formation of katabatic flows over long-lasting snow patches strongly affecting the temporal evolution of snow surface temperature patterns. The snow cover distribution is also shown to be of vital importance for the frequency of stable internal boundary layer development over snow. For situations with a clear evidence of stable internal boundary layer development over snow, the data reveal a very shallow atmospheric layer adjacent to the snow cover decoupled from the warm-air advection above. These measurements confirm previous wind tunnel experiments that also evidenced a decoupling of the air adjacent to the snow cover from the warmer air above, especially within topographical depressions and when ambient wind velocities are low. For these situations, in particular, all tested energy balance models strongly overestimated the turbulent sensible heat flux directed toward the snow cover.

Journal

Journal of HydrometeorologyAmerican Meteorological Society

Published: Oct 1, 2017

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off