Estimating Soil Properties and Relationship to Landscape Properties in Arctic Tundra using Aerial Platform and Geophysical Monitoring

Abstract:

Investigating linkages between subsurface and surface properties at various spatial and temporal scales is crucial for terrestrial ecosystem understanding because near-surface soil hydrological and biogeochemical processes are generally influenced by both compartments and because co-interactions between sampled soil properties and remote sensing data is crucial to extrapolate soil characteristics in sufficiently high resolution over modeling-relevant scales. In this study, we investigate linkages between soil and landscape property dynamics in the Arctic tundra in Barrow, AK along transects that traverse a range of geomorphological conditions, including low- to high- centered polygons. Landscape characteristics are inferred from topographic, multi-spectral and thermal-infrared imaging measurements using either a kite-, pole- and tram- based platform at various temporal and spatial scales from continuous monitoring along a 35 m long transect to occasional campaigns along 500x40 m corridors. Soil properties are inferred using electrical resistivity tomography (ERT), time-domain reflectometery (TDR), temperature measurements, and soil samples analysis.

Overall, this study enables the identification of spatiotemporal links between various soil and landscape properties (incl. water inundation, vegetation, topography, thaw layer thickness, soil water content, temperature, electrical conductivity, snow thickness) and inform on the complementary nature of various ground- and aerial-based approaches and proxies to estimate soil properties within a framework that considers uncertainty, resolution, and spatial coverage. Among other results, a relatively strong relationship is observed between changes in soil electrical conductivity, water content, thaw layer thickness and vegetation state. This confirms the importance of water distribution on various processes including vegetation dynamics, thermal conductivity, surface-subsurface energy exchange, redox reactions and biogeochemical mechanisms. Identifying such links is crucial to extrapolate strong knowledge from point-scale and core-based biogeochemical measurements at specific sites over larger scales to ultimately improve parameterization of models simulating ecosystem feedbacks to climate.