A Comparison of Satellite and Aircraft-Mounted Thermal Observations of Freeze/Thaw Cycling of the Alaska Tundra and Boreal Forests during the Carbon in the Arctic Vulnerability Experiment (CARVE)

Abstract:

Freeze/thaw (F/T) related surface processes in the Arctic are important as they bracket negative and positive modes in the flux of CO2 and CH4 between the surface and atmosphere. The Carbon in the Arctic Vulnerability Experiment (CARVE) monitors carbon gas cycling in Alaskan using aircraft-deployed gas sampling instruments along with remote sensing observations of the land surface condition. A nadir-pointed, forward looking infrared (FLIR) imager mounted on the CARVE aircraft is used to measure upwelling mid-infrared spectral radiance at 3-5 microns. The FLIR instrument was operated during the spring, summer and fall seasons of 2013 and 2014 during clear sky conditions and targeting ecosystem components affecting the carbon cycle. The instantaneous field of view (IFOV) of the FLIR instrument allows for a resolution of ~36 cm from a height of 500 m. This high resolution data allow for the discrimination of individual landscape components such as soil, vegetation and surface water features in the image footprint. We assess the effectiveness of the FLIR thermal images in monitoring thawing and inundation processes of individual ecosystem components of importance in biogeochemical cycling. We also observe how these individual components scale using coarse resolution satellite observations of land surface temperature (LST) from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Freeze/thaw state determined from the Advanced Microwave Scanning Radiometer (AMSR2) on JAXA’s Shizuku (GCOM-W1) satellite.

Portions of the work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautic and Space Administration.