TITLE:
To Measure the Changing Relief of Arctic Rivers: A Synthetic Aperture RADAR Experiment in Alaska
AUTHORS:
Reginald R. Muskett
KEYWORDS:
Alaska, Tundra, Experiment, RADAR, Polarimetry
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.6 No.9,
September
30,
2018
ABSTRACT: This river crossing the lowland tundra-permafrost of the continuous permafrost
zone of the Alaska North Slope can have extensive floodplain relief not
simply created by channel migration during spring floods alone. Many of the
rivers have channel-beds inherited from glacial landscapes and Holocene to
present-day paraglacial and periglacial processes and mountain gradient
sources [1] [2] [3] [4]. Interest is turning to understand effects from permafrost
and ice wedge networks (ground ice) thaw, degradation and erosion and
how such effects impact carbon and water equivalent mass balance. The 2015
flooding of the Sagavanirktok River crossing the Alaska North Slope brings
this and additional impacts to-and-by human infrastructure into focus. Geodetic
methods to measure centimeter to millimeter-scale changes using aircraft-
and satellite-deployed Synthetic Aperture (SA) RAdio Detection And
Ranging (RADAR) cannot ignore volume scattering. Backscatter and coherence
at L-frequency and others possess both surface and volumetric scattering.
On lowland tundra underlain by permafrost volume scattering dominants
the RADAR backscatter coherence (the results of this work and [16]).
Measurement of the L-frequency penetration depth for evaluation of mass
change (carbon and water equivalent loss and transport) through permafrost
and ground ice thaw-degradation with erosion is necessary. The Jet Propulsion
Laboratory-National Aeronautical and Space Administration airborne Uninhabited
Aerial Vehicle SAR (UAVSAR) L-frequency full quad-polarimetry
cross-pole HHVV (polarization rotation, Horizontal to Vertical) confirms the
dominance of volume scattering on lowland tundra (RADAR-soft targets)
whereas surface scattering (HHHH or VVVV, no rotation) dominates on river
channel deposits, rock outcrops and metal objects (RADAR-hard targets).
Quantifying polarization rotation and the L-frequency penetration depth on
lowland tundra are challenges for a new field validation and verification experiment.