Cloud forcing of surface energy balance from in situ measurements in diverse mountain glacier environments
<p>Clouds are an important component of the climate system, yet our understanding of how they directly and indirectly affect glacier melt in different climates is incomplete. Here we analyse high-quality datasets from 16 mountain glaciers in diverse climates around the globe to better understa...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-08-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/16/3331/2022/tc-16-3331-2022.pdf |
| Summary: | <p>Clouds are an important component of the climate system,
yet our understanding of how they directly and indirectly affect glacier
melt in different climates is incomplete. Here we analyse high-quality
datasets from 16 mountain glaciers in diverse climates around the globe to
better understand how relationships between clouds and near-surface
meteorology, radiation and surface energy balance vary. The seasonal cycle
of cloud frequency varies markedly between mountain glacier sites. During
the main melt season at each site, an increase in cloud cover is associated
with increased vapour pressure and relative humidity, but relationships to
wind speed are site specific. At colder sites (average near-surface air
temperature in the melt season <span class="inline-formula"><0</span> <span class="inline-formula"><sup>∘</sup></span>C), air temperature
generally increases with increasing cloudiness, while for warmer sites
(average near-surface air temperature in the melt season <span class="inline-formula">≫0</span> <span class="inline-formula"><sup>∘</sup></span>C), air temperature decreases with increasing
cloudiness. At all sites, surface melt is more frequent in cloudy compared
to clear-sky conditions. The proportion of melt from temperature-dependent
energy fluxes (incoming longwave radiation, turbulent sensible heat and latent
heat) also universally increases in cloudy conditions. However, cloud cover
does not affect daily total melt in a universal way, with some sites showing
increased melt energy during cloudy conditions and others decreased melt
energy. The complex association of clouds with melt energy is not amenable
to simple relationships due to many interacting physical processes (direct
radiative forcing; surface albedo; and co-variance with temperature, humidity
and wind) but is most closely related to the effect of clouds on net
radiation. These results motivate the use of physics-based surface energy
balance models for representing glacier–climate relationships in regional-
and global-scale assessments of glacier response to climate change.</p> |
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| ISSN: | 1994-0416 1994-0424 |