講演情報
[ACC42-02]アラスカ内陸部・ポーカーフラットにおける融解深、地表面変位、植生の空間分布
*阿部 隆博1、岩花 剛2,3、甘田 岳4、蟹江 俊仁5、斉藤 和之6、飯島 慈裕7 (1.京都大学フィールド科学教育研究センター、2.アラスカ大学フェアバンクス校国際北極圏研究センター、3.北海道大学北極域研究センター、4.森林総合研究所、5.北海道科学大学工学部都市環境学科、6.海洋研究開発機構、7.東京都立大学大学院都市環境科学研究科)
キーワード：
Permafrost、融解深、地表面変位、植生、地形、干渉SAR
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.