title: Extrapolating active layer thickness measurements across Arctic polygonal terrain using LiDAR andNDVIdata sets.
abstract: Landscape attributes that vary with microtopography, such as active layer thickness (ALT), are labor intensive and difficult to document effectively through in situ methods at kilometer spatial extents, thus rendering remotely sensed methods desirable. Spatially explicit estimates ofALTcan provide critically needed data for parameterization, initialization, and evaluation of Arctic terrestrial models. In this work, we demonstrate a new approach using high-resolution remotely sensed data for estimating centimeter-scaleALTin a 5 km2area of ice-wedge polygon terrain in Barrow, Alaska. We use a simple regression-based, machine learning data-fusion algorithm that uses topographic and spectral metrics derived from multisensor data (LiDAR and WorldView-2) to estimateALT(2 m spatial resolution) across the study area. Comparison of theALTestimates with ground-based measurements, indicates the accuracy (r2= 0.76, RMSE ±4.4 cm) of the approach. While it is generally accepted that broad climatic variability associated with increasing air temperature will govern the regional averages ofALT, consistent with prior studies, our findings using high-resolution LiDAR and WorldView-2 data, show that smaller-scale variability inALTis controlled by local eco-hydro-geomorphic factors. This work demonstrates a path forward for mappingALTat high spatial resolution and across sufficiently large regions for improved understanding and predictions of coupled dynamics among permafrost, hydrology, and land-surface processes from readily available remote sensing data.
authors.affiliation: Los Alamos National Laboratory Los Alamos, New Mexico, USA.
authors.forename: Chandana
authors.initials: C
authors.lastname: Gangodagamage
authors.affiliation: Los Alamos National Laboratory Los Alamos, New Mexico, USA.
authors.forename: Joel C
authors.initials: JC
authors.lastname: Rowland
authors.affiliation: Lawrence Berkeley National Laboratory Berkeley, California, USA.
authors.forename: Susan S
authors.initials: SS
authors.lastname: Hubbard
authors.affiliation: Los Alamos National Laboratory Los Alamos, New Mexico, USA.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Brumby
authors.affiliation: Water and Environmental Research Center and International Arctic Research Center, University of Alaska Fairbanks Fairbanks, Alaska, USA.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Liljedahl
authors.affiliation: Lawrence Berkeley National Laboratory Berkeley, California, USA.
authors.forename: Haruko
authors.initials: H
authors.lastname: Wainwright
authors.affiliation: Los Alamos National Laboratory Los Alamos, New Mexico, USA.
authors.forename: Cathy J
authors.initials: CJ
authors.lastname: Wilson
authors.affiliation: Los Alamos National Laboratory Los Alamos, New Mexico, USA.
authors.forename: Garrett L
authors.initials: GL
authors.lastname: Altmann
authors.affiliation: Lawrence Berkeley National Laboratory Berkeley, California, USA.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Dafflon
authors.affiliation: Lawrence Berkeley National Laboratory Berkeley, California, USA.
authors.forename: John
authors.initials: J
authors.lastname: Peterson
authors.affiliation: Lawrence Berkeley National Laboratory Berkeley, California, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Ulrich
authors.affiliation: Department of Biological Sciences, University of Texas at El Paso El Paso, Texas, USA.
authors.forename: Craig E
authors.initials: CE
authors.lastname: Tweedie
authors.affiliation: Oak Ridge National Laboratory Oak Ridge, Tennessee, USA.
authors.forename: Stan D
authors.initials: SD
authors.lastname: Wullschleger
keywords: Alaska; active layer thickness; barrow; eco-hydro-geo-thermal regimes; frozen ground; ice wedge polygons; thaw depth