Presentation Information
[ACC42-02]Spatial variations of thaw depth, surface displacement and vegetation in the Poker Flat Researh Range, interior Alaska
*Takahiro Abe1, Go Iwahana2,3, Gaku Amada4, Shunji Kanie5, Kazuyuki Saito6, Yoshihiro Iijima7 (1.Field Science Education and Research Center, Kyoto University , 2.International Arctic Research Center, University of Alaska Fairbanks, 3.Arctic Research Center, Hokkaido University, 4.Forestry and Forest Products Research Institute, 5.Faculty of Engineering Department of Civil and Environmental Engineering, Hokkaido University of Science, 6.Japan Agency of Marine-Earth Science and Technology, 7.Graduate School of Urban Enviornmental Studies, Tokyo Metropolitan University)
Keywords:
Permafrost,Thaw depth,Surface displacement,Vegetation,Topography,InSAR
Recent climate changes have stimulated permafrost thawing, impacting several aspects, such as ecohydrological changes and infrastructure destruction. It is crucial to assess the impact of recent environmental disturbances on permafrost thawing in the context of global warming, particulary in the southern limit of permafrost regions where the consequences are likely to be significant. To address this issue, we have started carring out fieldwork, satellite observations, and numerical simulations at the Poker Flat Research Range in interior Alaska. Thaw depths under different surface conditions were measured and compared with the results of the Advanced Land Observing Satellite-2/4 (ALOS-2/4) L-band interferometric synthetic aperture radar (InSAR), which is operated by the Japan Aerospace Exploration Agency. We also compared them with the results of pseudo-3D numerical simulations, which we used to calculate the depth of the top of the permafrost table. Spatial variations in surface vegetation were confirmed using satellite optical images and a field survey. Our preliminary results show that the thaw depth in the fire scar burned in 2004 and in anthropogenically disturbed areas is much larger than that in non-disturbed areas. This tendency is also consistent with InSAR-based surface displacement data. However, the thaw depth records suggest that spatial heterogeneity on the order of several meters, and that micro-topography is likely to be important. We plan to conduct denser field observations of thaw depth during our next fieldwork to compare with the satellite and simulation results in two horizontal dimensions.