V. M. Kotlyakov

Two New Glacier Systems in Northeastern Eurasia

Recent decades are characterized by progressively increasing cosmic information on glacier sizes. The effectively used satellite images obtained by the LANDSAT/TM, SPOT/HRV, JERS/OPS, and ASTER systems [1] are now supplemented with high� resolution satellite information: Ikonos, QuickBird, EROS, OrbVie, WorldView, ALOS, Cartosat, and Tet�

Significant features of the calendar of the late Pleistocene glacial cycles

Comparison of the δD deuterium record in the ice cores at the Antarctic Vostok and Dome C stations with the δ18 oxygen isotope in bottom oceanic sediments has elucidated the boundaries of glacial cycles in the late Pleistocene and revealed their inner symmetry: the longer the cycles, the more distant they were from the interglacial that occurred approximately 400 kyr ago. The symmetry is also manifested in the reversal of the sawtooth sequence of the cycles in that period. Wavelet analysis shows that symmetry was induced by amplitude modulation of climate oscillations on the precession and obliquity time scales and by frequency modulation on the scales of the eccentricity of the Earth’s orbital motion around the Sun.

Contemporary glacier systems of continental Eurasia

We distinguished 32 regional glacier systems in continental Eurasia. We found that 80% of the glacier area and 90% of the glacier volume are concentrated in

Punctuated equilibrium of the surface above subglacial Lake Vostok in antarctica

Progress in understanding the surface dynamics above the subglacial Lake Vostok is achieved owing to use of the ICESat satellite laser elevation measurements, which enabled us to determine surface fluctuations with precision up to 3 cm. A new idea on punctuated equilibrium of the surface above Lake Vostok is elaborated; this idea is concluded in irregular, sharp vertical displacements of the ice surface by up to 40 cm. Deformation of the surface is accompanied with a common raising or lowering, and with local vertical displacements up to 20 cm in amplitude. It has been proved experimentally that snow transport on the surface above the lake causes only redistribution of snow and forms fractal structures that do not have any effect on surface deformation. The form of the surface is not an inclined plane due to many bends that are particularly related to ice flowing on the lake water area.

Lead–lag relationships between atmospheric trends of temperature and carbon dioxide concentrations during the pliocene

Reconstructions of the average global near-surface air temperature and carbon dioxide concentration in the atmosphere for the late Pliocene are compared. For this purpose, a special technique of multiscale analysis based on wavelets was developed. It is found that temperature changes on timescales of 100 to 500 kyr lead the respective changes in the carbon dioxide concentration at about 10–25 kyr. It means that these reconstructions cannot be used for assessing the climate sensitivity to changes in the carbon dioxide concentration.

New data on current changes in the mountain glaciers of Russia

Based on systematic surveys and analysis of the satellite images under the GLIMS international project, the rate of glacier shrinkage and the increase in this rate for the past 15 years are estimated.

Changes in the mass balance of the Antarctic Ice Sheet over 50 years

The mass balance of the Antarctic Ice Sheet has been calculated based on instrumental estimates of the grounded ice discharge and snow accumulation data. The boundaries and sectional areas of the main ice catchment basins in West and East Antarctica have been determined, and the data on the grounded ice discharge and snow accumulation in these basins have been systematized. The intensity of accumulation and ablation processes in Antarctica has noticeably increased over the last 50 years. The mass balance of the ice sheet in East Antarctica has been and remains positive, while in West Antarctica it was positive in the middle of the last century and has become negative by now. The mass balance of the entire Antarctic Ice Sheet has been and remains positive, while the mass growth has noticeably decreased over the last 50 years.

Is climate predictable on a geological time scale

The aim of our work is to show that the global climate is predictable on a geological time scale (several tens and hundred thousands of years) on the basis of the structure of the peaks in the power spectra of the Pleistocene climate oscillations, which are the responses of the climate system to variations in solar radiation due to the orbital cyclicity of obliquity and precession of the Earth’s orbit.

Fractals in fluctuations of Antarctic ice sheet surface elevation

Progress in reconstructing the mechanism of the influence of drifting snow on changes in the ice surface elevation, when it moves with velocity of 2–5 m/year, was achieved owing to space-based laser altimetry and the discovery of fractal patterns of the elevation fluctuations. They consist in the growth of variance of elevation changes by an increased lag. The variance grows in the power law dependence in the scaling range of 70 km. The wavelet analysis revealed a wide spectrum of spatial frequencies and demonstrated that they occur in the range of 1.4–22.5 km–1. The discovered properties of changes in the surface elevation subordinate to the Gaussian distribution with zero mean indicate dynamic equilibrium of the present-day Antarctic ice sheet.

Cascades of subglacial lakes in Antarctica

Progress in understanding cascades of subglacial lakes in Antarctica and in the dynamics of their surface was derived using satellite laser altimetry measurements ICESat. The morphological and dynamical signs indicate subglacial lakes and the positions of their shore lines. Oscillations of surfaces in transition zones are periodic, while the changes in surface elevation above subglacial lakes are random. The pattern of surface displacements above cascades of subglacial lakes in Antarctica and their transition zones as similar. In the sense of technology, this paper initiates the method of mapping subglacial lakes based on satellite laser measurements of elevation.