Nathan Wales, NGEE Hydrology Masters Student from New Mexico
Tech, working with LANL NGEE hydrologists Brent Newman and Cathy Wilson, is
putting the finishing touches on the deployment of water sampling and
measurement equipment that will be used to carry out a tracer experiment at the
Barrow Environmental Observatory NGEE Arctic intensive field site. The NGEE
team deployed 75 macro-rhizons over the past 2 days, in order to collect soil
water samples at multiple soil depths across two polygons types in order to
track and quantify the role of polygon surface and frost table micro-topography
in controlling subsurface horizontal flow of water in the landscape.
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Nathan installs a
collar (green tube) around a well hole to ensure that the dilute sodium bromide
tracer cannot flow into the well hole through surface water pathways during
rain events. Brent Newman (background)
installs the macro-rhizons at 15cm, 25 cm and 35 cm below the ground surface.
Subsurface soil water samples collected with the macro-rhizons will be analyzed
in the BARC laboratory to quantify how fast the tracer applied at the surface
of the high center polygon will infiltrate into the soil and move sideways
through the subsurface down to the subsoil in the troughs.
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Most global climate models assume that all subsurface water
flux is one dimensional, in the vertical direction; driven into the soil by
gravity and negative soil water pressures (suction) during rainfall, and drawn
out of the soil and into the atmosphere by evaporation and plant transpiration.
But analysis of new NGEE in-situ geochemical data, and analysis of seasonal
inundation patterns using remote sensing data, both suggest that horizontal
water flow, well after snow melt, may be important in determining the spatial
distribution of chemical constituents and biogeochemical processes in low
relief Arctic coastal plain environments. Water level and tracer data will be
used together to inform NGEE’s Arctic Terrestrial Simulator, that will be used
to help interpret the tracer study results and improve our understanding of
water and chemical constituent transport in the Arctic.
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Nathan programs the
water level sensor to record water levels every 10 minutes in the shallow (1m
deep) wells deployed across the polygons.
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UTEP researchers,
Florencia and Steve, visit the low center polygon tracer study site to
photograph NGEE wells for Craig Tweedie’s BAID GIS project. BAID archives and
serves GIS and other spatial data for all research activities in the BEO.
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Golden plover inspects
experimental design.
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