Project Funding: 2016 - 2020

NRA: 2016 NASA: Terrestrial Ecology   

Funded by NASA

Abstract:
We propose to advance methods of retrieving belowground biomass and permafrost active layer properties by developing accurate radar scattering and inverse scattering models of layered ground that include a combination of organic and mineral soils, overlain by vegetation, and containing vegetation roots. We will use the radar forward scattering models to develop corresponding methods of simultaneously retrieving root biomass, permafrost active layer thickness, and soil moisture profiles for both organic and mineral layers using the ABoVE Foundational Airborne Measurements, particularly P-band (70 cm) and L-band (24 cm) measurements from the AirMOSS and UAVSAR instruments, respectively. The proposed study will benefit the ABoVE campaign by providing foundational datasets supporting regional investigations. This work takes advantage of the baseline set of data and products established by an ongoing Interdisciplinary Research in Earth Science (IDS) Program project that has aimed to estimate the active layer thickness along a 2500 km-long transect in Alaska, covered by 6 AirMOSS flights in two years (2014 2016). The work proposed here, however, will develop substantially more sophisticated radar scattering model, retrieval algorithm, and geospatial data products for the permafrost regions, including modeling of vegetation roots, which has not been addressed before. A limited set of ground measurements are also planned to support radar scattering model parameterization as well as the validation of retrieved products; these data will be used with other biophysical data collections enabled by ABoVE including vegetation parameters derived from NASA s Laser Vegetation Imaging Sensor (LVIS) measurements for regional calibration and refinement of radar models and retrieval algorithms, leading to improved monitoring of soil processes in Alaskan and Canadian permafrost landscapes. This proposal directly responds to the Terrestrial Ecology Program s seeking to strengthen the theoretical and scientific basis for measuring Earth surface properties using reflected, emitted, and scattered electromagnetic radiation. By providing accurate estimate of spatiotemporal distribution of permafrost active layer properties, this work addresses Question 3 and Question 4 of Tier 2 Science Questions, that is What processes are controlling changes in the distribution and properties of permafrost and what are the impacts of these changes? and What are the causes and consequences of changes in the hydrologic system, particularly the amount, temporal distribution, and discharge of surface and subsurface water? This study also indirectly helps address How are environmental changes affecting critical ecosystem services and how are human societies responding?

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile
• NASA Arctic-Boreal Vulnerability Experiment (ABoVE) Project Profile