Experimental Evaluation of the Influence of the Seawater Characteristics on Spatial and Temporal Variations of the Sound Speed in the Southern Abyssal, Intermediate and Shelf Zones of the Caspian Sea

2021 ◽  
Vol 67 (2) ◽  
pp. 134-146
Author(s):  
Siamak Jamshidi ◽  
Marzieh Yousefi
Keyword(s):  
Caspian Sea ◽  
Experimental Evaluation ◽  
Sound Speed ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
The Caspian Sea

Spatial and Temporal Variations of Sound Speed at the PN Section

2004 ◽  
Vol 60 (4) ◽  
pp. 673-679 ◽  
Author(s):  
Lian-Gang Lü ◽  
Hong-Xia Chen ◽  
Ye-Li Yuan
Keyword(s):  
Sound Speed ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Pn Section

scholarly journals Sea ice phenology in the Caspian Sea

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Forough Fendereski
Keyword(s):  
Sea Ice ◽  
Caspian Sea ◽  
Temporal Variations ◽  
Trophic Levels ◽  
Spatial And Temporal Patterns ◽  
The Caspian Sea ◽  
Ice Melt ◽  
Covered Area ◽  
Phonological Features ◽  
Caspian Seal

To understand the spatial and temporal variations in the extent and timing of sea ice in the Caspian Sea (CS), 15 years of sea ice presence and its phenology (freeze-up, break-up, and duration) were studied in the Northern CS (NCS) for a period from 2004 to 2018. This study indicated that the percentage of sea ice covered area in the CS showed fluctuations ranging from 54.2% in 2004 to more than 89% in 2006 and 2008. This study, furthermore, found regional differences within the NCS in sea ice phonological features during 2004 to 2018. Specifically, earlier sea ice formation, later ice melt, and longer ice periods were observed in the eastern than the western NCS. Noticeable interannual changes were also observed in the timing and duration of the NCS ice (2004-2018). However, most parts of the NCS did not show significant trends (P>0.05) in the formation, decay, and duration of sea ice and their interannual variability. The observed spatial and temporal patterns in the CS ice can have implications for phytoplankton blooms and higher trophic levels, such as fish and endangered Caspian seal populations and merits further investigation.

scholarly journals Spatial and Temporal Variations of Extreme Precipitation in Central Asia during 1982–2020

Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
Yalin Tian ◽  
Zhongwei Yan ◽  
Zhen Li
Keyword(s):  
Central Asia ◽  
Extreme Precipitation ◽  
Large Scale ◽  
Precipitation Amount ◽  
Circulation Pattern ◽  
Temporal Variations ◽  
Precipitation Extremes ◽  
Spatial And Temporal Variations ◽  
Observation Data ◽  
The Caspian Sea

As one of the largest arid and semi-arid regions in the world, central Asia (CA) is very sensitive to changes in regional climate. However, because of the poor continuity of daily observational precipitation records in CA, the spatial and temporal variations of extreme precipitation in recent decades remain unclear. Considering their good spatial and temporal continuity, gridded data, such as Climate Prediction Center (CPC) global precipitation, and reanalysis data, such as ERA-Interim (ERA), are helpful for exploring the spatial–temporal variations of extreme precipitation. This study evaluates how well CPC and ERA can represent observed precipitation extremes by comparing the differences in eight extreme precipitation indices and observation data at 84 meteorological stations. The results indicate that the CPC (except for 1979–1981) is more suitable for depicting changes in precipitation extremes. Based on the CPC data for the period 1982–2020, we found that seven indices of precipitation extremes, including consecutive wet days (CWD), max1-day precipitation amount (Rx1day), max5-day precipitation amount (Rx5day), number of heavy precipitation days (R10), very wet days (R95p), annual total precipitation in wet days (PRCPTOT), and simple precipitation intensity index (SDII) have increased by 0.2 d/10a, 0.9 mm/10a, 1.8 mm/10a, 0.3 d/10, 8.4 mm/10a, 14.3 mm/10a and 0.1 mm/d/10a, respectively, and the consecutive dry days (CDDs) have decreased by −3.10 d/10a. It is notable that CDDs decreased significantly in the north of Xinjiang (XJ) but increased in Kyrgyzstan (KG), Tajikistan (TI), and eastern Turkmenistan (TX). The other indices increased clearly in the west of XJ, north of Kazakhstan (KZ), and east of KG but decreased in the south of KG, TI, and parts of XJ. For most indices, the largest change occurred in spring, the main season of precipitation in CA. Therefore, the large-scale atmospheric circulation in April is analyzed to contrast between the most and least precipitation years for the region. A typical circulation pattern in April for those extremely wet years includes an abnormal low-pressure center at 850 hpa to the east of the Caspian Sea, which enhances the southerly winds from the Indian Ocean and hence the transportation of water vapor required for precipitation into CA. This abnormal circulation pattern occurred more frequently after 2001 than before, thus partly explaining the recent increasing trends of precipitation extremes in CA.

The sound speed in southern deepwater zone of the Caspian Sea, off Anzali Port

2011 ◽  
Vol 57 (2) ◽  
pp. 180-191 ◽  
Author(s):  
S. Jamshidi ◽  
N. B. Abu Bakar
Keyword(s):  
Caspian Sea ◽  
Sound Speed ◽  
The Caspian Sea

THE NUMBER AND QUALITATIVE CHARACTERISTICS OF FRY FISH IN SHALLOW COASTAL WATERS OF THE VOLGA IN THE SUMMER-AUTUMN PERIOD OF 2012

2017 ◽  
pp. 65-73
Author(s):  
Edward Vladimirovich Nikitin
Keyword(s):  
Fish Species ◽  
Coastal Waters ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Volga River ◽  
Commercial Fish ◽  
Autumn Period ◽  
Fish Juveniles ◽  
Qualitative Characteristics ◽  
Shallow Coastal Waters

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.

On the type locality of the steppe ribbon racer, Psammophis lineolatus (Brandt, 1838) (Serpentes: Lamprophiidae)

2020 ◽  
Vol 324 (2) ◽  
pp. 262-272
Author(s):  
I.V. Doronin ◽  
T.N. Dujsebayeva ◽  
K.M. Akhmedenov ◽  
A.G. Bakiev ◽  
K.N. Plakhov
Keyword(s):  
Caspian Sea ◽  
Type Specimen ◽  
Type Locality ◽  
Eastern Coast ◽  
Zoological Museum ◽  
Western Coast ◽  
The Caspian Sea ◽  
Original Species ◽  
Academy Of Sciences ◽  
Made In

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).

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