Changes of hydrological regime in the mountain catchments of the Crimean Peninsula

2020 ◽  
Author(s):  
Anastasiia Zemlianskova ◽  
Olga Makarieva ◽  
Nataliia Nesterova ◽  
Danil Arkhipov
Keyword(s):  
Water Resources ◽  
Current Flow ◽  
Vegetation Type ◽  
Meteorological Data ◽  
Flow Characteristics ◽  
Hydrological Regime ◽  
The Black Sea ◽  
Historical Period ◽  
Crimean Peninsula ◽  
Crimean Mountains

<p>Crimean water resources are unevenly distributed and mainly generated at the slopes of the Crimean Mountains affecting water supply of population and industry of the peninsula. The study of water resources has been limited for the last 30 years due to political situation and little quantitative information is available about climate change impact on hydrological regime of Crimean rivers. The aim of the study was the assessment of current flow characteristics for three rivers originating from the Crimean Mountains (the Derekoyka River at Yalta; 49.7 km<sup>2</sup>, the Demerdjy River at Alyshta, 53 km<sup>2</sup>; the Kokkozka River at Golybinka, 83.6 km<sup>2</sup>) and their comparison to the historical period (1960-1990) data. The study area is characterized by a Mediterranean climate and has a pronounced high-altitude zoning. Main vegetation type is the oak forests and shrubs. The highest elevation of the slopes reaches 1500 m.</p><p>Due to the lack of hydrological data for the last 30 years, the assessment of current flow characteristics was conducted based on hydrological modelling and observed meteorological data. The hydrological model Hydrograph was used in the study. The model was successfully used for the simulations of streamflow in similar climate for the basins of the Black Sea coast of Russia (Makarieva et al., 2018; 2019). The model was parametrized based on the data on typical landscapes of the studied area. The verification of streamflow and water balance simulation results was conducted for the historical period (1960-1990). The model was used to produce streamflow hydrographs for the period of 1991-2018 based on meteorological data. The changes of hydrological regime of Crimean rivers was assessed in comparison with historical period. The results of the study will be presented.</p>

Mid- and Late Holocene hydrological and geochemical changes in Lake Chokrak (NE Crimea)

2020 ◽  
Author(s):  
Yevhenii Rohozin ◽  
Karl Ljung
Keyword(s):  
Sediment Core ◽  
Hydrological Regime ◽  
The Black Sea ◽  
Lake Basin ◽  
Organic Carbon Content ◽  
Sea Level Changes ◽  
Crimean Peninsula ◽  
Geochemical Composition ◽  
The Holocene ◽  
High Organic Carbon Content

<p>The Crimean Peninsula has around 50 saline lakes, which formed during the Holocene marine transgression. These lakes are valuable archives of the Holocene sea-level changes in the Black Sea, but their chronologies and evolution remain largely unknown. This study presents reconstructions of evolution of the Lake Chokrak basin and its depositional environment during the last 8000 years. At present, the lake is hypersaline and separated from the Sea of Azov by a narrow sandbar. The environmental reconstructions are based on multi-proxy data including shell content, organic geochemical and x-ray fluorescence analyses and radiocarbon dating of an 11-m sediment core. The aim of the study is to provide new insights into the evolution history of the lake in the region where such data are limited. Based on the interpretation, the following succession of stages was recognized in the lake evolution. Around 8000 cal yr BP, an open relatively shallow marine embayment existed in the study area, which is evidenced by high contents of Mn, indicating well-oxygenated waters, and presence of shells of <em>Cerastoderma edule</em>, which is favoured by shallow calm waters. Lamination of the sediments during this stage indicates relatively stable marine conditions. A deeper transgressive stage is observed from 7000 to 6500 cal yr BP when waters became less oxygenated, the grain size decreased and laminations disappeared. Precipitation of carbonates at the end of this stage indicates seawater evaporation. A dry stage from 6500 to 6200 cal yr BP is characterized by further decrease in water level and precipitation of gypsum. Starting from 6200 cal yr BP, a renewed transgressive stage is observed with increased water oxygenation, accumulation of fine sediments and precipitation of carbonates. From 5400 to 5000 cal yr BP higher erosion is demonstrated by an increase in Zr, Ti, Rb and Si contents and occurrence of sand layers in the sediment core. After 5000 cal yr BP starts a dry stage of the basin, which is connected to the slower rate of the Holocene sea transgression. Precipitation of evaporites (carbonates, halite, gypsum) increased at this time and fine-grained clays accumulated in the basin. This stage is also characterized by virtually continuous presence of <em>C. edule</em> shells. Relatively high organic carbon content and C/N ratios imply increased input of terrestrial organic material throughout this stage. The infilling of the basin and formation of the sandbar started around 3000 cal yr BP when clay sediments intermixed with sand layers. A transitional stage from semi-open to closed basin lasted from 1400 to 800 cal yr BP and it is characterized by precipitation of evaporites and disappearance of shells. The current stage (from 800 cal yr BP to present) of the closed lake basin is characterized by sediment lamination, high precipitation of gypsum and potassium salts, and complete absence of molluscs due to high salinity of the brine. The obtained results show that hydrological regime and geochemical composition of the lake were influenced by complex interaction of climatic, local tectonic and eustatic factors throughout its history.</p>

scholarly journals Ichthyoplankton of The Shelf and Deep Water Areas of the North and Northeast of the Black Sea in The Spring Season

2021 ◽  
Vol 21 (05) ◽  
pp. 255-263
Author(s):  
Tatyana Klimova ◽  
Irina Vdodovich ◽  
Polina Podrezova
Keyword(s):  
Black Sea ◽  
Hydrological Regime ◽  
Shelf Zone ◽  
The Black Sea ◽  
Commercial Fishing ◽  
The Caucasus ◽  
Crimean Peninsula ◽  
The North ◽  
Younger Age ◽  
Water Species

This paper is focused on the ichthyoplankton species composition and spatial distribution in the Black sea shelf zone and the deepwater regions off Crimean Peninsula and coast of the Caucasus during the spring hydrological season. Recent changes in the hydrological regime of the Black sea induced by the climate warming have led to an extension of the active and productive spawning of the dominant temperate-water species Sprattus sprattus until the end of the spring hydrological season. An intensive spawning of sprat was detected in March, April and May 2016, 2017 and 2019, which was confirmed by a predominance of younger age group larvae. The maximum number of eggs reached 224 ind./m2 , and the larvae - 116 ind./m2. The wide size range of larvae as well as the low proportion of larvae with empty guts evidenced a favorable fodder base for their survival. The reduction in the age and sizeweight composition of sprat stock in the Black sea observed since 2016 as a result of an increase in its commercial fishing on the shelf of the Crimean Peninsula, did not affect sprat’ spawning activity.

MODERN HYDROGRAPHIC AND WATER MANAGEMENT ZONING OF UKRAINE’S TERRITORY – IMPLEMENTATION OF THE WFD-2000/60/EC

2020 ◽  
Author(s):  
V.K. Khilchevskyi ◽  
Keyword(s):  
Water Management ◽  
Water Resources ◽  
River Basins ◽  
River Basin Management ◽  
The Black Sea ◽  
Main Function ◽  
River Basin Management Plans ◽  
Management Plans ◽  
The Crimea ◽  
Sea Coast

In contrast to the hydrological and hydrochemical zoning, hydrographic and water management zoning of Ukraine (2016) was created on a basin basis, taking into account the boundaries of river basins, and not physiographic zoning. The main function of hydrographic and water management zoning is water management. Primary is hydrographic zoning, and water management - based on it. The description of modern hydrographic zoning of the territory of Ukraine, approved in 2016 by the Verkhovna Rada of Ukraine and included in the Water Code of Ukraine is given. Hydrographic zoning is carried out for the development and implementation of river basin management plans. On the territory of Ukraine nine areas of river basins are allocated: Dnipro; Dnister; Danube; Southern Bug; Don; Vistula; rivers of the Crimea; rivers of the Black Sea coast; rivers of the Azov Sea coast 13 sub-basins are allocated in four river basins district. The water management zoning is described - the division of hydrographic units into water management areas, which is carried out for the development of water management balances. In the regions of the river basins in the territory of Ukraine allocated 132 water management areas, 59 of which are located in the Dnipro basin. About 9,000 bodies of surface water allocated for monitoring in Ukraine. Approved zoning is the implementation of the provisions of the EU Water Framework Directive 2000/60 / EC in the management of water resources in Ukraine. Modern hydrographic and water management zoning of the territory of Ukraine approximates the management of water resources of the state to European requirements.

Self-organising map rainfall-runoff multivariate modelling for runoff reconstruction in inadequately gauged basins

2012 ◽  
Vol 43 (5) ◽  
pp. 603-617 ◽  
Author(s):  
Adebayo J. Adeloye ◽  
Rabee Rustum
Keyword(s):  
Water Resources ◽  
Meteorological Data ◽  
Rainfall Runoff ◽  
Main River ◽  
Multivariate Modelling ◽  
Southwest Nigeria ◽  
Management Schemes ◽  
Viable Approach ◽  
Self Organising Map ◽  
Gauged Basins

Water resources assessment activities in inadequately gauged basins are often significantly constrained due to the insufficiency or total lack of hydro-meteorological data, resulting in huge uncertainties and ineffectual performance of water management schemes. In this study, a new methodology of rainfall-runoff modelling using the powerful clustering capability of the self-organising map (SOM), unsupervised artificial neural networks, is proposed as a viable approach for harnessing the multivariate correlation between the typically long record rainfall and short record runoff in such basins. The methodology was applied to the inadequately gauged Osun basin in southwest Nigeria for the sole purpose of extending the available runoff records and, through that, reducing water resources planning uncertainty associated with the use of short runoff data records. The extended runoff records were then analysed to determine possible abstractions from the main river source at different exceedance probabilities. This study demonstrates the successful use of emerging tools to overcome practical problems in sparsely gauged basins.

Quantitative estimation on contribution of climate changes and watershed characteristic changes to decreasing streamflow in the Huangshui Basin, China

2021 ◽  
Author(s):  
Xizhi Lv ◽  
Shaopeng Li ◽  
Yongxin Ni ◽  
Qiufen Zhang ◽  
Li Ma
Keyword(s):  
Water Resources ◽  
Climate Changes ◽  
Yellow River ◽  
Potential Evapotranspiration ◽  
Quantitative Estimation ◽  
Meteorological Data ◽  
Characteristic Parameter ◽  
Research Area ◽  
Watershed Characteristic ◽  
Streamflow Change

<p>In the past 60 years, climate changes and underlying surface of the watershed have affected the structure and characteristics of water resources to a different degree It is of great significance to investigate main drivers of streamflow change for development, utilization and planning management of water resources in river basins. In this study, the Huangshui Basin, a typical tributary of the upper Yellow River, is used as the research area. Based on the Budyko hypothesis, streamflow and meteorological data from 1958-2017 are used to quantitatively assess the relative contributions of changes in climate and watershed characteristic to streamflow change in research area. The results show that: the streamflow of Huangshui Basin shows an insignificant decreasing trend; the sensitivity coefficients of streamflow to precipitation, potential evapotranspiration and watershed characteristic parameter are 0.5502, -0.1055, and 183.2007, respectively. That is, an increase in precipitation by 1 unit will induce an increase of 0.5502 units in streamflow, and an increase in potential evapotranspiration by 1 unit will induce a decrease of 0.1055 units in streamflow, and an increase in the watershed characteristic parameter by 1 unit will induce a decrease of 183.2007 units in streamflow. Compared with the reference period (1958-1993), the streamflow decreased by 20.48mm (13.59%) during the change period (1994-2017), which can be attribution to watershed characteristic changes (accounting for 73.64%) and climate change (accounting for 24.48%). Watershed characteristic changes exert a dominant influence upon the reduction of streamflow in the Huangshui Basin.</p>

Analysis of potential seismic sources of tsunamis in the Black Sea region, using data from various catalogues

2021 ◽  
Author(s):  
Emil Oynakov ◽  
Liliya Dimitrova ◽  
Lyubka Pashova ◽  
Dragomir Dragomirov
Keyword(s):  
Black Sea ◽  
Scientific Evidence ◽  
Active Faults ◽  
Active Regions ◽  
The Black Sea ◽  
Earthquake Catalogues ◽  
Crimean Peninsula ◽  
Black Sea Region ◽  
Global Science ◽  
Using Data

<p>Low-laying territories along the Black Sea coastal line are more vulnerable to the possible high (long) waves due to tsunami events caused by strong earthquakes in the active seismic regions. Historically, such events are rare in the Black Sea region, despite some scientific evidence of tsunamis and their recordings through continuous sea-level observations with tide gauges built in certain places along the coast. This study analyses seismic data derived from different international earthquake catalogues - NEIC, ISC, EMSC, IDC and Bulgarian national catalogue (1981 - 2019). A catalogue of earthquakes within the period covering the historical to the contemporary seismicity with magnitudes M ≥ 3 is compiled. The data are processed applying the software package ZMAP, developed by Stefan Wiemer (http://www.seismo.ethz.ch/en/research-and-teaching/products-software/software/ZMAP/index.html). The catalogues' completeness is calculated to assess the reliability of the historical data needed to assess the risk of rare tsunami events. The prevailing part of the earthquakes' epicentres are in the seismically active regions of Shabla, the Crimean peninsula, the east and southeast coast of the Black Sea forming six main clusters, which confirmed previous studies in the region. In these areas, several active and potentially active faults, which can generate tsunamigenic seismic events, are recognized.</p><p><strong>Acknowledgements: </strong>The authors would like to thank the Bulgarian National Science Fund for co-funding the research under the Contract КП-СЕ-КОСТ/8, 25.09.2020, which is carried out within framework of COST Action 18109 “Accelerating Global science In Tsunami HAzard and Risk analysis” (AGITHAR; https://www.agithar.uni-hamburg.de/).</p>

scholarly journals Evaluating quantile-based bias adjustment methods for climate change scenarios

2021 ◽  
Author(s):  
Fabian Lehner ◽  
Imran Nadeem ◽  
Herbert Formayer
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Climate Model ◽  
Meteorological Data ◽  
Climate Change Signal ◽  
Historical Period ◽  
Climate Change Scenarios ◽  
Statistical Bias ◽  
Bias Adjustment ◽  
Direct Model

Abstract. Daily meteorological data such as temperature or precipitation from climate models is needed for many climate impact studies, e.g. in hydrology or agriculture but direct model output can contain large systematic errors. Thus, statistical bias adjustment is applied to correct climate model outputs. Here we review existing statistical bias adjustment methods and their shortcomings, and present a method which we call EQA (Empirical Quantile Adjustment), a development of the methods EDCDFm and PresRAT. We then test it in comparison to two existing methods using real and artificially created daily temperature and precipitation data for Austria. We compare the performance of the three methods in terms of the following demands: (1): The model data should match the climatological means of the observational data in the historical period. (2): The long-term climatological trends of means (climate change signal), either defined as difference or as ratio, should not be altered during bias adjustment, and (3): Even models with too few wet days (precipitation above 0.1 mm) should be corrected accurately, so that the wet day frequency is conserved. EQA fulfills (1) almost exactly and (2) at least for temperature. For precipitation, an additional correction included in EQA assures that the climate change signal is conserved, and for (3), we apply another additional algorithm to add precipitation days.

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