Regional scale patterns of remotely sensed methane hotspots with respect to Arctic lake change and thermokarst geomorphology
Clayton Elder, Jet Propulsion Laboratory, clayton.d.elder@jpl.nasa.gov (Presenter)
David R. Thompson, Jet Propulsion Laboratory / Caltech, david.r.thompson@jpl.nasa.gov
Latha Baskaran, NASA JPL, latha.baskaran@jpl.nasa.gov
Ingmar Nitze, Alfred Wegener Institute for Polar and Marine Research, initze@dmawi.de
Guido Grosse, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, guido.grosse@awi.de
Nicholas Hasson, University of Alaska Fairbanks, nhasson@alaska.edu
Melanie Engram, University of Alaska, Fairbanks, melanie.engram@alaska.edu
Natalie Tyler, University of Alaska Fairbanks, natyler@alaska.edu
Katey M. Walter Anthony, University of Alaska, Fairbanks, kmwalteranthony@alaska.edu
Charles E. Miller, NASA JPL, charles.e.miller@jpl.nasa.gov
Arctic and boreal wetlands and lakes are experiencing complex ecological changes as a result of warming. The potential for rapidly thawing permafrost to promote large increases in methane (CH4) emissions via ground subsidence and ponding (thermokarst), and permafrost carbon mineralization is of particular concern for accelerating the permafrost carbon feedback (PCF) [Turetsky et al. 2020]. However, complex hydrological dynamics produce large uncertainties for the sign and magnitude of carbon loss in modeling and forecasting efforts. Determining CH4’s current and future contributions to the PCF is challenging due to sparse observations, high spatiotemporal variability, and heterogeneous Arctic landscapes. As a result, top-down (observation-based) and bottom-up (model/inventory-based) evaluations of annual Arctic and boreal CH4 emissions disagree by 50-200% [McGuire et al. 2012; Peltola et al. 2019]. Constraining the current budget and forecast uncertainty in future Arctic emissions will require scale-bridging approaches that reconcile high spatiotemporal variability and regional to continental scale coverage. To this end, we compiled multiple large remote sensing datasets to study relationships between Landsat-derived Arctic lake and thermokarst landscape morphology trends with remotely-sensed (AVIRIS-NG) CH4 emission hotspot detections. Preliminary analyses from a lake-and-wetland-rich 1,750 km2 study area of the Yukon Kuskokwim Delta, AK, USA reveal discrete correlations between recently wetted areas and CH4 hotspot detections. However, in an analysis of over 1,200 lakes > 1 ha, hotspots were detected in greater abundance surrounding lakes that have shrunk in area since 1999 (p < 0.05) (Fig. 1). Our preliminary results imply a complex response of CH4 emissions surrounding dynamic permafrost environments. Ongoing analyses seek to further elucidate patterns related to waterbody size, permafrost ice content, and discrete thermokarst features.
Poster: Poster_Elder_21_71_37.pdf
Associated Project(s):
Poster Location ID: 21
Presentation Type: Poster
Theme: Crosscutting