ABoVE

SAR-based lake ebullition maps. Panel a shows Alaska study regions with SAR footprints outlined in yellow. Subsequent panels show SAR-based CH4 ebullition maps for b) Barrow Peninsula, c) Atqasuk, d) Toolik, e) northern Seward Peninsula, and f) Fairbanks. Study lakes with field-based measurements are outlined (b,c) or boxed (d,e,f) in white. Orange boxes in panel f indicate anthropogenic study lakes.

Spatial estimates of total carbon combustion at 30 m resolution across the 2015 fire perimeters in Saskatchewan (a) and sampled fires (b, c, d). The spatial extents of sampled fires are shown as blue rectangles in (a).

Site sampling plan used for characterizing active layer soils (left). Axes are in meters. At Imnavait Creek, active layer thickness (ALT) was measured on transects intersecting a central soil pit. Soil dielectric properties, in situ moisture and temperature profiles were measured, and soil samples were collected for analyses from the soil pit (right).

Sixteen measurement sites located across interior Alaska, USA, and at one site in Yukon, Canada. Sites C17K, C26K, E23, F17, H31, and I17 are collocated with the seismic stations.

Downscaled MERRA-2 snow depth (in meters) data. Images show snow depth for two time periods: spring snow melt for 23-30 April, 2007 (left) and during early snow accumulation for 30 September-7 October, 2007 (right).

The custom-built chamber for measuring in situ trace gas fluxes from soil/vegetation and water surfaces. The chamber (~ 0.5 m3) provides adequate height to enclose emergent grasses and reeds.

Vegetation point-intercept (VPI) any-hit cover metric data were combined with Landsat imagery to develop fractional maps of any-hit cover for four aggregated plant functional types (PFTs);  shrubs bryophytes, lichen, and herbs for the upland tundra area of the Y-K Delta, Alaska. VPI data were collected from plots in areas burned in 1971, 1985, 2005, and 2015.

Field sites, ecoregions, and total area burned (millions of hectares; Mha) in each of the ecoregions in the study domain over time. Grey dotted line in the inset represents the simple linear regression, with red shading for the 95% confidence intervals, of burned area for all ecoregions combined. Analyses were completed using the field site groupings, located within the six ecoregions defined by the EPA Level II Ecoregions of North America.

Model-simulated 1 km mean active layer thickness (ALT) map from 2001 to 2015. Black dots are locations of circumpolar active layer monitoring (CALM) sites used for comparison of observed ALT to modeled ALT. CALM data are not provided. The areas with ALT greater than 300 cm depth are shown in dark gray.

Example of color-infrared imagery shown alongside the corresponding semi-automated open water classification at Old Crow Flats, Alaska.