Yi, Y., J. S. Kimball, M. Moghaddam, and R. H. Reichle:
"Characterizing permafrost active layer dynamics and sensitivity to landscape spatial heterogeneity: A case study in Alaska"
Presentation at the AGU Fall Meeting, San Francisco, CA, USA, 2016.

Abstract:
An important feature of the Arctic is the large spatial heterogeneity in permafrost and active layer conditions, which are generally poorly represented in global climate and carbon models and can lead to large uncertainties in predicting regional ecosystem responses and feedbacks to climate change. In this study, we developed a spatially integrated analysis and modeling framework to investigate the sensitivity of permafrost active layer processes to sub-grid heterogeneity in vegetation, terrain and disturbance factors. The model framework combines detailed field measurements of vegetation, microclimate and active layer properties with local scale (~100m resolution) soil active layer retrievals from airborne radar remote sensing, and landscape level (≥1-km resolution) environmental observations from satellite microwave and optical-infrared sensors. Satellite observations, including land surface temperature, snow cover extent and soil moisture from the MODIS and SMAP sensors, are used as primary model drivers for estimating snow/soil thermal conductivity and soil temperature profiles. The model estimates regional patterns and recent changes (2001-present) in permafrost extent (PE) and ALT across Alaska at landscape scale (~1-km resolution). Local scale maps of active layer conditions and additional land parameters include soil moisture and surface organic layer thickness from combined low frequency (L+P-band) airborne radar backscatter from the NASA UAVSAR and AirMOSS sensors will be used to inform the coarser landscape model simulations and quantify the effects of surface organic layer and soil moisture spatial heterogeneity on the estimated soil active layer dynamics. These results are used to clarify regional patterns and recent changes in permafrost active layer conditions, and underlying environmental controls across Alaska.


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NASA-GSFC / GMAO / Rolf Reichle