13:45 〜 14:00
[U03-01] Thermokarst development and its impact on local livelihoods in permafrost regions, inferred from satellite remote sensing data
キーワード：Permafrost、Thermokarst、Remote sensing、Numerical simulation、Transdisciplinary study
Thermokarst is an irreversible process that changes local landform underlain by ice-rich permafrost, and has been observed in eastern Siberia and Alaska. In the area of Lena and Aldan rivers in eastern Siberia, topographic changes due to thermokarst have been remarkably identified (e.g., Fedorov et al., 2014; Crate et al., 2017), which has significant impacts on infrastructure, water cycle and ecosystems, and lives of neighbors. Continuous observation of thermokarst in the Lena-Aldan interfluve has been performed in Yukechi by a research group of Melnikov Permafrost Institute during the last three decades. However, there were no comprehensive observations of thermokarst subsidence, which led to the uncertainty of assessment of permafrost degradation in the entire area. The spatial distribution of thermokarst subsidence could be an important index to evaluate permafrost degradation in the area, which is essential for visualization of the degradation and future projections.
Synthetic Aperture Radar (SAR) is a notable remote sensing technique which can obtain information about surface properties and distance between ground and satellite without any instruments on the ground surface. Interferometric SAR (InSAR) is a method to measure surface displacement by calculating the phase difference between two different SAR data. InSAR has been utilized to reveal geophysical phenomena related to surface displacements such as crustal deformation and glacier flow. The number of application studies of InSAR to permafrost monitoring has been increasing, and InSAR has become one of the essential tools for understanding permafrost dynamics. By combining SAR analysis with other remote sensing data, we are able to monitor and assess permafrost conditions, some of which are validated by field survey data (e.g., Abe et al., 2020; Iijima et al., 2021).
Such remote sensing data are useful for performing numerical simulations of surface displacements associated with ground freeze-thaw cycles. To mimic surface displacement field by high resolution InSAR data, spatial and temporal changes of not only ground temperature but also surface topography, hydrology and vegetation effects needs to be taken into account (e.g., Kanie et al., 2023). Moreover, recent snow depth increase may significantly impact on temporal changes of ground temperature during wintertime, which can lead to greater surface uplift due to frost heave. To better understand permafrost degradation triggered by such environmental disturbances, numerical simulations including environmental change factors are essential.
These scientific findings have significant implications for proposed climate change adaptation measures for local livelihoods. By combining the wisdom and experience of local people with our scientific results, we are taking an interdisciplinary approach to reveal frozen ground environmental changes and the impact on local livelihoods from a scientific, engineering and humanistic perspective. We will present our recent activities and future plans in eastern Siberia, Alaska, and Mongolia.
Synthetic Aperture Radar (SAR) is a notable remote sensing technique which can obtain information about surface properties and distance between ground and satellite without any instruments on the ground surface. Interferometric SAR (InSAR) is a method to measure surface displacement by calculating the phase difference between two different SAR data. InSAR has been utilized to reveal geophysical phenomena related to surface displacements such as crustal deformation and glacier flow. The number of application studies of InSAR to permafrost monitoring has been increasing, and InSAR has become one of the essential tools for understanding permafrost dynamics. By combining SAR analysis with other remote sensing data, we are able to monitor and assess permafrost conditions, some of which are validated by field survey data (e.g., Abe et al., 2020; Iijima et al., 2021).
Such remote sensing data are useful for performing numerical simulations of surface displacements associated with ground freeze-thaw cycles. To mimic surface displacement field by high resolution InSAR data, spatial and temporal changes of not only ground temperature but also surface topography, hydrology and vegetation effects needs to be taken into account (e.g., Kanie et al., 2023). Moreover, recent snow depth increase may significantly impact on temporal changes of ground temperature during wintertime, which can lead to greater surface uplift due to frost heave. To better understand permafrost degradation triggered by such environmental disturbances, numerical simulations including environmental change factors are essential.
These scientific findings have significant implications for proposed climate change adaptation measures for local livelihoods. By combining the wisdom and experience of local people with our scientific results, we are taking an interdisciplinary approach to reveal frozen ground environmental changes and the impact on local livelihoods from a scientific, engineering and humanistic perspective. We will present our recent activities and future plans in eastern Siberia, Alaska, and Mongolia.