scholarly journals Ice gouging topography on the Caspian and Aral seas bottom

2019 ◽  
Vol 151 (2) ◽  
pp. 35-50 ◽  
Author(s):  
S. A. Ogorodov ◽  
S. V. Maznev ◽  
P. I. Bukharitsin
Keyword(s):  
Remote Sensing ◽  
Sea Level ◽  
Caspian Sea ◽  
Ground Surface ◽  
Direct Methods ◽  
Climatic Changes ◽  
Aral Sea ◽  
Anthropogenic Influence ◽  
Gas Field ◽  
Side Scan Sonar

Ice gouging is a destructive mechanical impact of ice on the underlying ground surface associated with ice cover dynamics, ice hummocking (ridging) and formation of grounded hummocks (stamukhas) under hydrometeorological factors and coastal topography. Ice scours in the Northern Caspian Sea were discovered in 1950s, but ice gouging processes were taken into consideration only in 2012, when the accident on Kashagan gas field (Kazakhstan) occurred. Recently we found ice scours on the dried bottom of the Aral Sea. Ice gouging microrelief on the Caspian seabed was researched using specialized geophysical equipment — side-scan sonar and multibeam sounding. We have a unique opportunity to study ice scours on the Aral Sea dried bottom by direct methods, but now they are observed only by remote sensing technologies. When sea level is not stable the most intensive gouging takes place on the depths from 2 to 5 m. Ice scours are widespread on the Caspian and Aral seabed because their level was significantly changing during XX century. Climatic changes and anthropogenic influence can cause changes in conditions of ice scour formation. Studying of the ice scours parameters on the Aral Sea dried bottom has a great economic and fundamental importance for comprehension of ice gouging conditions and intensity in shallow freezing seas and big lakes.

scholarly journals Reconstruction of Caspian Sea-Level Fluctuations: Radiocarbon Dating Coastal and Bottom Deposits

Radiocarbon ◽  
1993 ◽  
Vol 35 (3) ◽  
pp. 409-420 ◽  
Author(s):  
Yu. A. Karpytchev
Keyword(s):  
Sea Level ◽  
Salt Marshes ◽  
Caspian Sea ◽  
Climatic Changes ◽  
Short Term ◽  
The Caspian Sea ◽  
Sea Level Fluctuations ◽  
The Impact ◽  
Basin Area

Owing to the large basin area of the Caspian Sea, fluctuations in its level reflect climatic changes in the northern hemisphere. To reconstruct these fluctuations, I collected mollusk shells, plant debris, carbonates and organic matter samples for 14C dating from deposits of ancient salt marshes, depressions and bars formed during significant sea-level decline. I studied the impact of eolian sedimentation via parallel dating of carbonates and other materials. The data demonstrate that sea level rises during periods of cooling and falls during warming periods; this is true for both long-term (2–2.5 ka) and short-term climatic changes.

FEATURES OF CONSTRUCTION OF ON-BOARD HELICOPTER RADAR ICE EXPLORATION ON BASIS OF CIRCULAR GROUND SURFACE WITH SYNTHESIS OF APERTURE ROTATING ANTENNA

2019 ◽  
pp. 31-37
Author(s):  
I. G. Antсev ◽  
A. P. Aleshkin ◽  
V. V. Vladimirov ◽  
E. O. Kudrina ◽  
O. L. Polonchik ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Ground Surface ◽  
Rotor Blades ◽  
Navigation Systems ◽  
Propeller Blade ◽  
Antenna Aperture ◽  
Sensing System ◽  
Radar Systems ◽  
Simulation Results ◽  
Circular Antenna Array

The results of modeling the processes of receiving and processing the signals of remote sensing of the Earth’s surface using helicopter radar and synthesizing the antenna aperture due to its placement on the rotating rotor blades are presented. The mathematical correctness of the application of the developed algorithms for processing probing signals, as well as the uniqueness of the measurements, was confirmed. At the same time, the dimensions of the synthesized aperture due to the rotation of the radiator placed at the end of the propeller blade are equivalent to a circular antenna array with a diameter of tens of meters. The functionality of the remote sensing system based on this radar meets the requirements for ice observation and navigation systems for seagoing ships off the coast. The simulation results confirm the promise of further research in this direction and can be used in the development of radar systems with synthesized antenna aperture mounted on rotating rotor blades.

scholarly journals Lidar measurement of snow depth: a review

2013 ◽  
Vol 59 (215) ◽  
pp. 467-479 ◽  
Author(s):  
Jeffrey S. Deems ◽  
Thomas H. Painter ◽  
David C. Finnegan
Keyword(s):  
Remote Sensing ◽  
Snow Depth ◽  
Near Infrared ◽  
Ground Surface ◽  
Lidar Measurement ◽  
Snow Hydrology ◽  
Sensing Technology ◽  
Transfer Error ◽  
Scale Range ◽  
Visible Wavelengths

AbstractLaser altimetry (lidar) is a remote-sensing technology that holds tremendous promise for mapping snow depth in snow hydrology and avalanche applications. Recently lidar has seen a dramatic widening of applications in the natural sciences, resulting in technological improvements and an increase in the availability of both airborne and ground-based sensors. Modern sensors allow mapping of vegetation heights and snow or ground surface elevations below forest canopies. Typical vertical accuracies for airborne datasets are decimeter-scale with order 1 m point spacings. Ground-based systems typically provide millimeter-scale range accuracy and sub-meter point spacing over 1 m to several kilometers. Many system parameters, such as scan angle, pulse rate and shot geometry relative to terrain gradients, require specification to achieve specific point coverage densities in forested and/or complex terrain. Additionally, snow has a significant volumetric scattering component, requiring different considerations for error estimation than for other Earth surface materials. We use published estimates of light penetration depth by wavelength to estimate radiative transfer error contributions. This paper presents a review of lidar mapping procedures and error sources, potential errors unique to snow surface remote sensing in the near-infrared and visible wavelengths, and recommendations for projects using lidar for snow-depth mapping.

scholarly journals Evolution of Sea Level of the Big Aral Sea from Satellite Altimetry and Its Implications for Water Balance

2005 ◽  
Vol 31 (4) ◽  
pp. 520-534 ◽  
Author(s):  
Jean-Francois Crétaux ◽  
Alexey V. Kouraev ◽  
Fabrice Papa ◽  
Muriel Bergé-Nguyen ◽  
Aanny Cazenave ◽  
...  
Keyword(s):  
Water Balance ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Aral Sea

scholarly journals Ceramic Traditions in the Forest-Steppe Zone of Eastern Europe

2021 ◽  
Vol 7 (1) ◽  
pp. 705-717
Author(s):  
Konstantin Mikhailovich Andreev ◽  
Alexander Alekseevich Vybornov
Keyword(s):  
Eastern Europe ◽  
Central Europe ◽  
Caspian Sea ◽  
Steppe Zone ◽  
Aral Sea ◽  
Cultural Tradition ◽  
Forest Steppe ◽  
Pottery Production ◽  
The Baltic ◽  
Early Pottery

Abstract Early pottery on the territory from the Eastern Caspian Sea and Aral Sea to Denmark reveals a certain typological similarity. It is represented by egg-shaped vessels with an S-shaped profile of the upper part and a pointed bottom. The vessels are not ornamented or decorated with incised lines, organized often in a net. This type of pottery was spread within hunter-gatherer ancient groups. The forest-steppe Volga region is one of the earliest centers of pottery production in Eastern Europe. The first pottery is recorded here in the last quarter of the seventh millennium BC. Its appearance is associated with the bearers of the Elshanskaya cultural tradition. The most likely source of its formation is the territory of Central Asia. Later, due to aridization, these ceramic traditions distributed further westward to the forest-steppe Don region. During the first half of the sixth millennium BC, groups associated with the bearers of the Elshanskaya cultural tradition moved westward. Significant similarities with the ceramic complexes of the Elshanskaya culture are found in materials from a number of early pottery cultures of Central Europe and the Baltic (Narva, Neman, and Ertebølle).

scholarly journals Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

Ocean Science ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 311-329 ◽  
Author(s):  
R. A. Ibrayev ◽  
E. Özsoy ◽  
C. Schrum ◽  
H. İ. Sur
Keyword(s):  
Sea Level ◽  
Wind Stress ◽  
Caspian Sea ◽  
Seasonal Cycle ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Coastal Currents ◽  
The Caspian Sea ◽  
Sea Surface Topography

Abstract. A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. The model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

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