scholarly journals Interannual variability of the ice-free period duration in the southwestern Kara Sea

2019 ◽  
Vol 65 (3) ◽  
pp. 239-254 ◽  
Author(s):  
O. Ya. Sochnev ◽  
K. A. Kornishin ◽  
Ya. О. Yefimov ◽  
Ye. U. Mironov ◽  
V. S. Porubayev
2020 ◽  
Author(s):  
Stanislav Myslenkov ◽  
Vladimir Platonov ◽  
Alexander Kislov ◽  
Ksenia Silvestrova ◽  
Igor Medvedev

Abstract. Recurrence of extreme wind waves in the Kara Sea strongly influences the Arctic climate change. The paper presents the analysis of wave climate and storm activity in the Kara Sea based on the results of numerical modeling. A third-generation wave model WaveWatchIII is used to reconstruct wind wave fields on an unstructured grid with a spatial resolution of 15–20 km for the period from 1979 to 2017. The mean and maximum wave heights, wavelengths and periods are calculated. The maximum significant wave height (SWH) for the whole period amounts to 9.9 m. The average long-term SWH for the ice-free period does not exceed 1.3 m. The seasonal variability of the wave parameters is analyzed. The interannual variability of storm waves recurrence with different thresholds (from 3 to 7 m) was calculated. A significant linear trend shows an increase in the storm wave frequency for the period from 1979 to 2017. A double growth in the reccurence was observed for cases with an SWH more than 3–5 m from 1979 to 2017. The local maximum of the storm waves more than 3–4 m was observed in 1995, and the minimum in 1998. The maximum value (four cases) of the number of storms with an SWH threshold 7 m is registered in 2016. The frequency of wind speeds and ice conditions contributing to the storm waves formation were analyzed. It is shown that trends in the storm activity of the Kara Sea are primarily regulated by the ice. If the ice cover decreases in the southern part of the sea that leads to the increase of the number of events only with SWH threshold more than 3–4 m. If in the entire sea the ice cover decreases that leads already to increase of the extreme storms. The frequency of strong and long-term winds has high interannual variability and a weak positive trend. The analysis of distribution functions of the storm events with an SWH more than 3 m was carried out. Six different sectors of the Kara Sea were analyzed to reveal spatial differences. A comparison of the different distribution laws showed that the Pareto distribution is in the best agreement with the data. Up to 99 % of the points are described by this distribution. However, the extreme events with an SWH more than 6–7 m deviate from the distribution, and their probability is approximately twice as less as that predicted by the Pareto distribution. Presumably, this deviation is caused by the combined impact of rare wind speed frequencies and anomalies of the sea ice conditions.


Oceanology ◽  
2018 ◽  
Vol 58 (4) ◽  
pp. 537-549
Author(s):  
A. B. Demidov ◽  
S. V. Sheberstov ◽  
V. I. Gagarin

Author(s):  
Zinaida V. Pushina ◽  
Galina V. Stepanova ◽  
Ekaterina L. Grundan

Zoya Ilyinichna Glezer is the largest Russian micropaleontologist, a specialist in siliceous microfossils — Cenozoic diatoms and silicoflagellates. Since the 1960s, she systematically studied Paleogene siliceous microfossils from various regions of the country and therefore was an indispensable participant in the development of unified stratigraphic schemes for Paleogene siliceous plankton of various regions of the USSR. She made a great contribution to the creation of the newest Paleogene schemes in the south of European Russia and Western Siberia, to the correlations of the Paleogene deposits of the Kara Sea.


2020 ◽  
Vol 54 (2) ◽  
pp. 497-513 ◽  
Author(s):  
L. N. Beldiman ◽  
I. N. Urbanavichene ◽  
V. E. Fedosov ◽  
E. Yu. Kuzmina

We studied in detail a moss-lichen component of Shokalsky Island vegetation for the first time and identified 79 species of mosses and 54 species and 2 subspecies of lichens and lichenicolous fungi. All species of mosses and 23 species and 2 subspecies of lichens and lichenicolous fungi are recorded for the first time for the island. The study is based on collections made in South West part of the island, in arctic tundra. We also explored the participation of the mosses and lichens in the main types of plant communities and the species distribution in 10 ecotopes. The paper describes the noteworthy findings (Abrothallus parmeliarum, Aongstroemia longipes, Arthonia peltigerea, Caloplaca caesiorufella, Catillaria stereocaulorum, Ceratodon heterophyllus, Lecanora leptacinella, Sphagnum concinnum, S. olafii) and features of bryo- and lichenoflora of Shokalsky Island.


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