Characterizing Thawing Permafrost Carbon Emissions: An Integrated Pilot Study in Support of Satellite Evaluation/Design and Earth System Modeling Capabilities
Abstract:We present a multi-disciplinary, multi-scaled study to measure methane (CH4) and carbon dioxide (CO2) above thawing permafrost at three sites, each representing a different ecosystem, near Fairbanks, AK. We have designed a unique and comprehensive array of ground experiments at these sites that will record permafrost depth and subsurface structure, meteorological data, and concentrations of key GHGs during seasonal ground thaw of the active layer in the summer. This is the first time that these types of measurements have been combined to provide a holistic view of the evolution of, and the atmospheric response to permafrost thaw. These data will allow us to estimate emission fluxes of carbon from the thawing permafrosts. To estimate a global source of GHG emissions from thawing permafrosts, we will use MODIS and Landsat-8 Operational Land Imager and Thermal Infrared Sensor data to “scale up” the data collected at the three sites on the basis of land surface type information. We refer to this effort as a pilot study as we will collect observations near Fairbanks, AK with the intent to expand our observational network in the future to other sites in North America, which will aid in the monitoring of changes in GHG emissions in the Arctic as well as complement and help interpret data collected by space-borne instruments, such as GOSAT, IASI, and AIRS.
Based on the data collected at the three sites and a variety of existing satellite data sets, we will develop a computationally-efficient parameterization of emissions from thawing permafrosts for use in the NASA GEOS-5 Atmospheric General Circulation Model (AGCM), thus benefiting ongoing efforts in the NASA Global Modeling and Assimilation Office (GMAO) to build an Earth System Model which is used for both retrospective and predictive simulations of important GHGs. We will use the AGCM to interpret the data collected by tracking methane and CO2 plumes from various sources that impact the three sites. In addition, we will use data collected from aircraft missions and surface stations to understand the signature ratios of trace gases that give important clues as to the identification of sources (e.g. urban, biomass burning).