Numerical modeling of annual mean hydrophysical fields in the Caspian Sea

Author(s):  
Akaki Girgvliani
2020 ◽  
Vol 8 (4) ◽  
pp. 284 ◽  
Author(s):  
Ayyuob Mahmoodi ◽  
Mir Ahmad Lashteh Neshaei ◽  
Abbas Mansouri ◽  
Mahmood Shafai Bejestan

The Nowshahr port in the southern coastlines of the Caspian Sea is among the oldest northern ports of Iran, first commissioned in the year 1939. In recent years, this port has been faced with severe sedimentation issues in and around its entrance that has had negative impacts on the operability of the port. The present study aims at identifying major reasons for severe sedimentation in the port entrance. First, field measurements were evaluated to gain an in-depth view of the hydrodynamics of the study area. Numerical models then were calibrated and validated against existing field measurements. Results of numerical modeling indicated that wind-induced current is dominant in the Caspian Sea. The numerical results also indicated that in the case of an eastward current direction, the interaction between current and the western breakwater arm would lead to the formation of a separation zone and a recirculation zone to the east of the port entrance region. This eddying circulation could transport suspend settled sediments from eastern shoreline towards the port entrance and its access channel. The results of this paper are mostly based on the study of current patterns around the port in the storm conditions incorporate with the identification of sediment sources.


2019 ◽  
Vol 44 (8) ◽  
pp. 529-539 ◽  
Author(s):  
I. P. Medvedev ◽  
E. A. Kulikov ◽  
I. V. Fine ◽  
A. E. Kulikov

2020 ◽  
Vol 11 (41) ◽  
pp. 151-164
Author(s):  
Mahmood Reza Akbarpour Jannat ◽  
Ehsan Rastgoftar ◽  
Somayeh Farhang Baftani ◽  
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...  

Author(s):  
R. Mahmoodi ◽  
A. A. Ardalan ◽  
M. Hasanlou

Numerical simulation results of wind wave in the Caspian Sea by using wind forcing data are presented. The numerical modeling which is applied in this study is based on numerical spectral wave model which is based on Navier-Stokes equations. It solves these equations through each of mesh elements. Moreover, in this model high-resolution unstructured grid for the Caspian Sea has been used in order to reach finer accuracy. The wind forcing data are given from European Centre for Medium-Range Weather Forecasts (ECMWF). The measurement data, which are gained from Ports and Marine Organisation (PMO) of Iran, are used in order to estimate the accuracy of the model. The results have shown better accuracy in comparison with PMO simulation. Mean of the coefficient of determination (R-squared) for significant wave height in this simulation is 0.8059, though, in PMO simulation this coefficient is reported 0.7056. Better accuracy requires more measurement data and also finer resolution of bathymetry data.


Author(s):  
Edward Vladimirovich Nikitin

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.


2020 ◽  
Vol 324 (2) ◽  
pp. 262-272
Author(s):  
I.V. Doronin ◽  
T.N. Dujsebayeva ◽  
K.M. Akhmedenov ◽  
A.G. Bakiev ◽  
K.N. Plakhov

The article specifies the type locality of the Steppe Ribbon Racer. The holotype Coluber (Taphrometopon) lineolatus Brandt, 1838 is stored in the reptile collection of the Zoological Institute of the Russian Academy of Sciences (ZISP No 2042). Literature sources provide different information about the type locality. A mistake has been made in the title of the work with the original species description: the western coast of the sea was indicated instead of the eastern one. The place of capture was indicated as “M. Caspium” (Caspian Sea) on the label and in the reptile inventory book of the Zoological Museum of the Academy of Sciences. The specimen was sent to the museum by G.S. Karelin. The “1842” indicated on the labels and in the inventory book cannot be the year of capture of the type specimen, just as the “1837” indicated by A.M. Nikolsky. In 1837, Karelin was in Saint Petersburg and in 1842 in Siberia. Most likely, 1837 is the year when the collection arrived at the Museum, and 1842 is the year when the information about the specimen was recorded in the inventory book (catalog) of the Zoological Museum of the Academy of Sciences. In our opinion, the holotype was caught in 1932. From Karelin’s travel notes of the expedition to the Caspian Sea in 1832, follows that the snake was recorded in two regions adjacent to the eastern coast of the Caspian Sea – Ungoza Mountain (“Mangyshlak Mountains”) and site of the Western Chink of Ustyurt between Zhamanairakty and Kyzyltas Mountains (inclusive) on the northeast coast of Kaydak Sor (“Misty Mountains”). In our article, Karelin’s route to the northeastern coast of the Caspian Sea in 1832 and photographs of these localities are given. The type locality of Psammophis lineolatus (Brandt, 1838) should be restricted to the Mangystau Region of the Kazakhstan: Ungoza Mountain south of Sarytash Gulf, Mangystau (Mangyshlak) Penninsula (44°26´ N, 51°12´ E).


Author(s):  
Nepomenko Leonid ◽  
◽  
Popova Natalia ◽  
Zubanov Stepan ◽  
Ostrovskaya Elena ◽  
...  

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