Project Funding: 2016 - 2019

NRA: 2016 NASA: Terrestrial Ecology   

Funded by NASA

Abstract:
Active biogeochemical processes create intense, localized methane (CH4) emissions sources across Arctic-boreal landscapes, but their contribution to the northern high latitude CH4 budget is uncertain and their spatial and temporal distributions are uncharacterized at the regional scale. Our research is driven by the questions: What are the dominant landscape and biogeochemical features associated with large CH4 source plumes in the ABoVE domain? and How do these characteristics differ in tundra vs boreal ecosystems? In Alaskan vs Canadian ecosystems? We test the hypothesis that CH4 emissions from geologic seeps contribute significantly to the permafrost carbon feedback. We will exploit recent breakthroughs in high-resolution (1-3m) CH4 imaging to identify, geolocate and quantify CH4 plumes from all imagery acquired with the Next Generation Airborne Visible Infrared Imaging Spectrometer (AVIRIS-NG) during the 2017 ABoVE Airborne campaign. We estimate that AVIRIS-NG surveys will detect >250 CH4 plumes from sub-permafrost (geologic) ebullition seeps and hundreds more plumes from a combination of aboveground seeps, wetlands hotspots, thermokarst slumps, energy exploration and infrastructure. The operational AVIRIS-NG On-board Real-Time Detection System and cluster-matched filter (CMF) retrieval algorithm enable us to deliver Quicklook CH4 plume products within 24 hours of acquisition and CMF CH4 plume products within 2 weeks of Level 1 data processing. We will follow up AVIRIS-NG CH4 plume detections with ground-truth field studies of selected sources near Noorvik, AK and Bethel, AK to validate the AVIRIS-NG observations and characterize the source process using isotopic analyses of collected gas samples. We will characterize the spatiotemporal variability of observed CH4 sources by analyzing high-resolution optical and synthetic aperture radar images of thermokarst lake ebullition seeps acquired during the cold season. Our use of isotope geochemistry, year-round flux sampling, and surveys of concentrated energy exploration and infrastructure will enable us to separate geologic and energy sector CH4 sources from ecologic sources, providing critical insight into the CH4 component of the permafrost carbon feedback. We will deliver maps of CH4 sources for the ABoVE domain and compare these to CH4 flux maps estimated from CARVE, AIRMETH, other measurements and models. The resulting data set will transform our understanding of the spatial distribution and magnitude of CH4 sources in the varied ecosystems of the ABoVE domain. Our investigation leverages collaboration with and significant investments from the NANA Regional Corporation (NANA). NANA will provide at no cost to our investigation: 1) Logistics for four team members to conduct ground-truth fieldwork on gas seeps in the Kobuk Delta region and near Kotzebue. 2) Permits for access to NANA land 3) Accommodation, transportation and local guides to explore gas seep sites in rural lakes near villages Additionally, NANA will provide a two-year graduate fellowship (stipend and related benefits) at the University of Alaska Fairbanks to Janelle Sharp, a native Alaskan and NANA Shareholder, who will use the results from this research as the basis of her thesis. NANA will also identify a resident researcher whom we will train to monitor seeps in the Noorvik-Kotzebue area year-round over multiple years. Our research addresses the ABoVE Tier 2 Science Question How are the magnitudes, fates, and land-atmosphere exchanges of carbon pools responding to environmental change, and what are the biogeochemical mechanisms driving these changes? Our expected findings of CH4 sources related to energy exploration will guide DOE and NRCanada as energy commerce evolves in the North. Our study of geologic thaw lake seeps links ABoVE to research in the Earth Science Directorate s Atmospheric Composition, Cryosphere Science, Hydrology and Solid Earth programs.

Publications:

Baskaran, L., Elder, C., Bloom, A. A., Ma, S., Thompson, D., Miller, C. E. 2022. Geomorphological patterns of remotely sensed methane hot spots in the Mackenzie Delta, Canada. Environmental Research Letters. 17(1), 015009. DOI: 10.1088/1748-9326/ac41fb

Elder, C. D., Thompson, D. R., Thorpe, A. K., Hanke, P., Walter Anthony, K. M., Miller, C. E. 2020. Airborne Mapping Reveals Emergent Power Law of Arctic Methane Emissions. Geophysical Research Letters. 47(3). DOI: 10.1029/2019GL085707

Engram, M., Walter Anthony, K. M., Sachs, T., Kohnert, K., Serafimovich, A., Grosse, G., Meyer, F. J. 2020. Remote sensing northern lake methane ebullition. Nature Climate Change. 10(6), 511-517. DOI: 10.1038/s41558-020-0762-8

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