Airborne electromagnetic and magnetic geophysical survey data of the Yukon Flats and Fort Wainwright areas, central Alaska, June 2010
Lyndsay B. BallBruce D. SmithB. J. MinsleyJared D. AbrahamClifford I. VossB. N. AstleyMaria Deszcz‐PanJames C. Cannia
14
Citation
15
Reference
10
Related Paper
Citation Trend
Abstract:
In June 2010, the U.S. Geological Survey conducted airborne electromagnetic and magnetic surveys of the Yukon Flats and Fort Wainwright study areas in central Alaska. These data were collected to estimate the three-dimensional distribution of permafrost at the time of the survey. These data were also collected to evaluate the effectiveness of these geophysical methods at mapping permafrost geometry and to better define the physical properties of the subsurface in discontinuous permafrost areas. This report releases digital data associated with these surveys. Inverted resistivity depth sections are also provided in this data release, and data processing and inversion methods are discussed.Keywords:
Wainwright
Geophysical survey
Geological survey
Using continuous data obtained from 17 monitoring sites, the permafrost temperature profiles and the depths of zero annual amplitude (DZAA) on the Qinghai-Tibet Plateau are examined. Permafrost thermal trumpet curves are generally narrow and the DZAAs are generally shallow in warm permafrost regions, especially at sites where the permafrost temperature is close to 0 °C. The observed DZAAs in warm permafrost regions are indeed generally less than 7.0 m and for three sites less than 4.0 m. In low-temperature permafrost areas, the situation is reversed: the thermal trumpet curves are generally wide and the DZAAs are generally deep. Theoretical and numerical analyses clearly show there is a causal relationship between permafrost warming and the decrease of the DZAA. Latent heat effects are buffering the increase of permafrost temperature and result in narrow thermal trumpet curves and shallow DZAAs. Based on observations and numerical analyses, this research suggests that most of the permafrost on the Qinghai-Tibet Plateau is undergoing internal thaw and the latent heat effects have important implications on the permafrost thermal regime. The temperature-dependent adjustments in permafrost will promote both the downward and upward degradation of permafrost as a result of climate warming.
Cite
Citations (27)