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1.
N.G. Granin I.B. Mizandrontsev V.V. Kozlov E.A. Tsvetova R.Yu. Gnatovskii V.V. Blinov I.A. Aslamov K.M. Kucher V.G. Ivanov A.A. Zhdanov 《Russian Geology and Geophysics》2018,59(11):1514-1525
Hydrophysical studies and mathematical modeling of ring structures during ice cover on Lake Baikal have shown that their existence at the stage of ice cover degradation is due to anticyclonic currents. Such currents can be generated as a result of local upwelling, which we associate with the rise of methane hydrates from the top layer of bottom sediments and their dissociation. Analysis of satellite images shows that the radii of ice rings range from 1300 to 2400 m, which is close to the baroclinic Rossby radius. The measured ice thicknesses in the area of the rings are in agreement with model calculations. Deep water renewal in Lake Baikal can also be associated with the rise of hydrates. 相似文献
2.
V. V. Blinov N. G. Granin I. B. Mizandrontsev R. Yu. Gnatovskii A. A. Zhdanov 《Water Resources》2017,44(3):417-427
For the first time, T,S-analysis was used to determine the specifics of seasonal variations in the vertical structure of Lake Baikal active layer. In the under-ice period, the active layer includes the under-ice, top winter, and upper intermediate water masses. The under-ice water mass, unlike other masses, shows an increase in mineralization to 100.74 mg/kg, which corresponds to a release of 71.1 g salt under 1 m2 of water surface in a layer 0–40 m in the process of salt freezing out during ice cover formation and accretion. In the phases of mixing (homothermy), the water masses of the active layer transform into a surface homogeneous mass. In summer and autumn, surface and upper intermediate water masses, separated by a water mass of summer thermocline can be identified. A specific feature of the summer thermocline water mass is the increased sum of ions because of an increase in HCO 3 - concentration at the decay of organic matter accumulating in the bottom part of the thermocline. The existence of the under-ice water mass and the water mass of summer thermocline was established in Lake Baikal for the first time. In the deep-water zone (>250 m), except for the bottom parts, the lower water masses (the lower intermediate and the deep) are permanent, their characteristics remaining stable during the year. The changes in the bottom water mass are due to the character of the processes of bottom water renewal. 相似文献
3.
Shimaraev M. N. Granin N. G. Domysheva V. M. Zhdanov A. A. Golobokova L. P. Gnatovskii R. Yu. Tsekhanovskii V. V. Blinov V. V. 《Water Resources》2003,30(6):623-626
Published results of studies and calculations based on data on the salinity of river and lake waters are used to assess the resulting horizontal water exchange between bed depressions in Baikal. The role of this process in the redistribution of nutrients in the lake is demonstrated using dissolved Si as an example. 相似文献
4.
M. N. Shimaraev A. A. Zhdanov R. Yu. Gnatovskii V. V. Blinov V. G. Ivanov 《Water Resources》2011,38(2):169-174
The specific features of cold bottom intrusion in Baikal are considered based on the results of observations of 1993–2009.
It is shown that the intrusion-related renewal of bottom water takes place not regularly and not simultaneously in different
hollows. Its maximums were recorded in Southern Baikal in 1997 and 2007, in Middle Baikal in 1995, 2006, and 2009, and in
Northern Baikal in 1997 and 2009. In these years, the volume of cold bottom layer in some hollows reached 200–470 km3 and its total cooling reached −20 to −60 MJ 109. Cold intrusions were more frequent and had greater effect on the bottom layer in Southern Baikal than in other parts of
the lake. The intrusions, especially in the years of their active development, are shown to cause water cooling in both the
bottom layer and the major part of the deep-water zone of all hollows. 相似文献
5.
N. G. Granin I. B. Mizandrontsev A. I. Obzhirov O. F. Vereshchagina R. Yu. Gnatovskii A. A. Zhdanov 《Doklady Earth Sciences》2013,451(1):784-786
The rate of aerobic oxidation of methane was calculated based on average profiles of the tritiumhelium age of the Baikal waters and concentrations of the dissolved methane in the water column. In the deep lake zone (>200 m), the intensity of oxidation vertically decreases and is (2–0.3) × 10?2 nl CH4l?1 days?1 in southern and central Baikal and (2.8–1.0) × 10?2 nl CH4 l?1 days?1 in northern Baikal. The effective coefficient of the oxidation rate in the lake depressions is 3.6 × 10?4, 3.3 × 10?4, and 3.7 × 10?4 days?1, respectively. At current methane concentrations in the water column, about 80 t of methane is oxidized per year. Oxidation of the dissolved methane in the water column was estimated at a possible increase of its concentration. 相似文献
6.
Shimaraev M. N. Troitskaya E. S. Blinov V. V. Ivanov V. G. Gnatovskii R. Yu. 《Doklady Earth Sciences》2012,442(2):272-276
Based on shipboard and satellite observations, the characteristics of upwelling in Lake Baikal in the period of direct temperature
stratification have been determined for the first time. Coastal upwellings appear annually under the effect of run-down and
alongshore winds and are traced along the coast to a distance of up to 60–100 km and up to 250 km in North Baikal. Analogous
to the way it occurs in seas, water rises from the depths of 100–200 m (350 m as a maximum) at the velocity of 0.1 × 10−2−6.5 × 10−2 cm/s. Divergence in the field of intràbasin cyclonic macrovortices produces upwelling in the Baikal pelagic zone and downwelling
in the vicinity of shores; this lasts from 7 to 88 days and covers the depth interval of 80–300 m in August and up to 400–800
m in early-mid November. The area of upwellings occupies up to 20–60% of the separate basins of the lake. Vertical circulation
of water in the field of pelagic upwellings leads to intensification of coastal currents and to formation of the thermobar
with a heat inert zone in the central part of the lake in November, and this thermobar is not observed in other lakes, at
that. 相似文献
7.
This paper presents the results on measurements of water temperature in Lake Baikal of 1972–2007. The abnormal warming during
this period was accompanied by gradual increase of the upper 300 m layer temperature, but did not affect the water state of
the deep zone. Temperature fluctuations in 1972–1992 mainly depended on dynamic influence of atmosphere on the water column
causing inter-annual changes in the activity of deep convection.
Published in Russian in Doklady Akademii Nauk, 2009, Vol. 426, No. 5, pp. 685–689.
Presented by Academician M.A. Grachev September 11, 2008
The article was translated by the authors. 相似文献
8.
M. N. Shimaraev V. M. Domysheva R. Yu. Gnatovskii V. V. Blinov M. V. Sakirko 《Geography and Natural Resources》2016,37(3):212-219
We investigated the influence of deep forced temperature convection on aeration of the bottom water layer in the pelagic zone of Baikal. Temperature T (± 0.002°C) and oxygen O2 concentration (± 0.01 mg/L) were measured by using the SBE-25 probe with the SBE-43 oxygen sensor in May-July 2006?2007 and 2009?2013. Oxygen input into the bottom layer with cold intrusions was determined for 79 cases. The study revealed a quantitative correlation between the heat deficit and the rise in oxygen content in the bottom layer during cold intrusions. This correlation was used to reconstruct the values of intrusion aeration of the bottom layer during 1993?2005. It is ascertained that the intrusion-caused 2006?2013-average oxygen input into Baikal’s bottom layer is virtually close to the annual oxygen demand for oxidation processes in the water column and bottom sediments. In the southern and middle parts of Baikal, intrusion-caused input of oxygen corresponds to a higher rate of its demand (4.5?4.6x10-4 mg/L per day). A slight increase in oxygen concentration was detected in the bottom layer of the South and Middle Baikal and a slight decrease in the bottom layer of North Baikal during 1993?2013. 相似文献
9.
A. A. Zhdanov R. Yu. Gnatovskii N. G. Granin V. V. Blinov I. A. Aslamov V. V. Kozlov 《Water Resources》2017,44(3):442-452
New data on under-ice currents in Lake Baikal have been obtained with the use of high-accuracy instruments. The obtained data were used to analyze the time and space variations of under-ice currents, to calculate the coefficients of horizontal turbulent exchange and turbulent energy dissipation rates, and to derive spectral estimates of the obtained results. The estimated structures of the under-ice boundary layer near the Angara opening and far from it (up to 5 km) were compared. 相似文献
10.
M. N. Shimaraev R. Yu. Gnatovskii V. V. Blinov V. G. Ivanov 《Doklady Earth Sciences》2011,438(1):652-655
The patterns of renewal of bottom waters in Lake Baikal under the influence of deep convection and intrusion of cold waters
have been considered based on the data of temperature surveys of Lake Baikal conducted in 1993–2009. The volumes of the cold
bottom layer with the maximums of 200–470 km3 in individual years and the values of its total cooling (−20–60 × 109 MJ) have been determined for South, Middle, and North Baikal. The renewal process is asynchronous and proceeds with different
activity in these parts of the lake, which indicates that the mechanisms that cause deep convection in the context of the
great latitudinal length and differences in the climate and hydrological processes manifest themselves regionally. The volume
of intrusions has been determined. Its average value for the period was higher in South Baikal (20 km3) than in Middle Baikal (9.8 km3) and North Baikal (8.6 km3). The volume of the intrusions in these parts of the lake was 30–70 km3 in some years. 相似文献