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SAHRA Webcam
on Mt. Bigelow updated every 5 minutes
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Among the ecosystems present in
the semi-arid environment of the southwestern US, Sky Island
Forest is unique and it has a unique relationship to the sparse
surface-water resources available in the region. This ecosystem
exists only at the top of mountains because it is only here
that, as a long-term average, precipitation input exceeds evapotranspiration
to the extent that forest vegetation can survive. Sky Island
Forests, therefore, command potentially significant source areas
for the water (some originally falling as snow) that ultimately
leaves topographically high ground to recharge aquifers in the
plains below by mountain-front recharge. Quantifying and understanding
water, energy and related
carbon cycling and budgets of this
sustainable source of water, is of direct
relevance to the mission of SAHRA.
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Mount Bigelow
Eddy Correlation Tower
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The SAHRA Mount Bigelow
project aims to provide an empirically based understanding
of the hydro-micrometeorological dynamics of a sky island
sub-alpine forest in the southwestern U.S.
The fundamental science issues in
question are:
- the characteristics
of the surface-atmosphere exchanges of water, energy and
carbon.
- the partitioning
of winter snow and
rain between evapotranspiration/ sublimation, deep drainage
and the near-surface environmental water resource that sustains
the forest.
In order to achieve our objective, a network of three below
canopy hydro-micrometeorological stations 10 m tall, and one
above canopy 30 m tall high resolution eddy correlation tower,
were deployed within a predominantly douglas fir/pine second
growth forest. This network will operate for a minimum of
two years and ideally for the next seven years, in order to
capture strong inter-annual climate variability, as well as
to leverage on the GEWEX-CEOP related activities as their
semi-arid sky island reference site for the larger basin modeling
activities. The Mount Bigelow project is the first study to
document, analyze, and model the water, energy, and (related)
carbon exchanges of the Sky Island Forest ecosystem. The observations
have year-round value. Data gathered in winter aids understanding
of how water resources are replenished by winter snow and
rain. Data collected in spring aids understanding of the partitioning
of water between deep drainage and the near-surface environmental
water resource that sustains the forest; while data gathered
in the summer and fall aids understanding of the evolution
of the environmental water resource as it is depleted by evapotranspiration
but replenished by monsoon storms.
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