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Surface Fluctuation above the Subglacial Lakes in Antarctica from ICESatтезисы доклада
- Авторы: Vasiliev L.N., Kotlyakov V.M., Kachalin A.B., Moskalevsky M.Yu, Tyuflin A.S.
- Сборник: From Knowledge to Action Conference (Montréal, Canada, 2012)
- Тезисы
- Год издания: 2012
- Место издания: Montréal, Canada
- Аннотация: Progress in understanding the surface dynamics above the subglacial lakes in Antarctica is achieved by using spatio-temporal ICESat altimetry. Morphological pattern of surface formation conforms well to the thermomechanical model of ice flowing above the subglacial lake. The surface forms concave and frontal bulge at the transition zones. Temporal variation of the elevation shows peaks and bottom of the surface around the transition zones A identifiable surface morphological and dynamical elevation signature define the lake location and its shoreline. There is a close correspondence between Vostok shoreline defined by Radio Echo Sounding and the morphological surface signature. Experiments aim at understanding the relation between the water body and the overlying ice especially with respect to stability of subglacial lakes. Special care was taken to resolve the behaviour of transition zones at high resolution. The geometrical approach has been applied at the pattern recognition and mapping of new subglacial lakes on Recovery Ice Stream and Dome A, Deformation of the surface is accompanied with a common rise and fall. The form of the surface above subglacial lakes is not an inclined plane due to bends that are predominantly related to topography of the bedrock. We took the new approach in dealing with spatio-temporal elevation change above the lakes. Spectrogram is a time-varying spectral representation that captures most of the spatio-temporal variance. The advantage of the spectrogram: it is simple and easy to be understood. High values of oscillation are associated with the transition zones. The elevation change in the transition zones is out of phase. The transition zones exhibit large variability of elevation change in the range of -1 to 1 meter. The transition zone estimated to be somewhere between 500 – 1500 meters wide. We found that different subglacial lakes exhibit varying degree of linkages on Recovery Ice Stream and Dome A. It may be thought as consisting of cascade of subglacial lakes. Elevation displacements above the cascade of lakes are usually in phase. The abrupt changes happen and the vertical motion of the neighbouring lakes is out of phase. Ten new subglacial lakes of Recovery Glacier and around Dome A which exhibit signs of direct linkage are identified by using a new technology.
- Добавил в систему: Москалевский Максим Юрьевич