Hydrological Profiles Research Articles

Hydrological profile observation scheme based on optical fiber sensing for polar sea ice buoy monitoring

The monitoring of hydrological elements in the polar region is the basis for the study of the dynamic environment under the ice. The traditional cross-season subglacial hydrological environment monitoring mainly relies on tether-type vertical profile measurement ice-based buoys, which have the advantages such as high reliability, high measurement accuracy, and real-time communication, while also has disadvantages of high-cost, large volume and weight, high power consumption, and complex layout. Therefore, it is urgent to develop a new type of ice-based profile buoy with low-cost, miniaturization, low power consumption, convenient deployment, and high reliability. In this paper, a novel optical fiber sensing scheme for ice-based buoy monitoring is proposed, which uses arrayed fiber grating to measure seawater temperature and depth profile and uses a dual-conduction mode resonance mechanism to measure seawater salinity. The temperature, depth, and salinity of seawater can be detected by an all-optical fiber technology in real-time. Preliminary experiments show that the temperature accuracy is ±0.1 °C in the range of -5∼35 °C, the salinity accuracy is ±0.03‰ in the range of 30‰∼40‰, and the vertical spatial resolution of depth can be adjusted in the range of 0∼1000 m, which can better meet the requirements of polar hydrological multi-layer profile observation. It can provide an innovative technology and equipment support for studying the spatiotemporal change process of the polar subglacial ocean.

Vertical structure characterization of acoustically detected zooplankton aggregation: a case study from the Ross Sea

Acoustic data were collected by means of Simrad EK60 scientific echosounder on board the research vessel “Italica” in the Ross Sea during the 2016/2017 austral summer as part of the P-Rose and CELEBeR projects, within the framework of the Italian National Research Program in Antarctica (PNRA). Sampling activities also involved the collection of vertical hydrological profiles using the SBE 9/11plus oceanographic probe. Acoustic data were processed to extract three specific scattering structures linked to Euphausia superba, Euphausia crystallorophias and the so called Sound-Scattering Layers (SSLs; continuous and low-density acoustic structures constituted by different taxa). Four different sectors of the study area were considered: two southern coastal sectors (between the Drygalski Ice Tongue and Coulman Island), a northern sector (~30 nmi East of Cape Hallett) and an offshore one spanning about 2 degrees of latitude from Coulman Island south to the Drygalski Ice Tongue. The vertical structure of each group in each area was then analyzed in relation to the observed environmental conditions. Obtained results highlighted the presence of different vertical structures (both environmental and acoustic) among areas, except for the two southern coastal sectors that were found similar. GAM modelling permitted to evidence specific relationships between the environmental factors and the vertical distribution of the considered acoustic groups, letting to hypothesize the presence of trophic relationships and differences in SSL species composition among areas. The advantages of acoustic techniques to implement opportunistic monitoring strategies in endangered ecosystems are also discussed.

Гидрологический профиль реки на водосборной территории бассейна Асса-Талас с учетом техноприродных процессов

На основе многолетних информационно-аналитических материалов гидрологическими постами РГП «Казгидромет» за 1925–2020 годы создана база исследования для изучения пространственно-временной оценки многолетних колебаний годового стока реки на территории водосбора бассейна Асса-Талас, с использованием метода гидрологической аналогии, линейных трендов, суммарных, разностных и обычных интегральных кривых, базирующихся на математической статистике. Исследования показали, что тенденция изменения среднегодового расхода воды рек на территории водосбора бассейна Асса-Талас за рассматриваемый период (1925–2020) отрицательная, где изменения гидрологического режима реки происходят симметрично и последовательно-пропорционально в пространственно-временном масштабе, наблюдается два квазиоднородных периода, характеризующих переход от природной деятельности на антропогенную. Оценка изменений водности рек на территории водосбора бассейна Асса-Талас и синхронности или асинхронности ее многолетних колебаний, выполненных на основе нормирования разностных интегральных кривых модульных коэффициентов среднегодового расхода воды с использованием метода разностно-интегральных кривых, показала, что во всех гидрологических постах с 1925 до 1975 года наблюдается многоводный цикл, а после этого начинается до настоящего времени маловодный цикл, но с различиями в сроках наступления фаз и амплитуды циклических колебаний. При этом количественное значение коэффициента вариации увеличивается от горной зоны в сторону южной пустыни, где расположены зоны магазинирования поверхностного стока и высокого среднегодового расхода воды во всех рассматриваемых реках наблюдаются в пределах от 1,0 до 25,0 % обеспеченности, а затем их количественное значение резко снижается, что характерно рекам, где источниками питания являются атмосферные осадки, таяние снежного покрова и грунтовые воды.

Extreme Hydrometeorological Conditions of Sediment Waves’ Formation and Migration in Peter the Great Bay (The Sea of Japan)

New data were obtained on the formation mechanisms of relief sediment waves (SWs) in Peter the Great Bay of the Sea of Japan. From the studies, we can assume that the sediment waves in the bay originate from two types of turbidity (TB) currents: (1) fine-dispersed TB currents caused by disintegrating internal waves and entrained by the Primorsky current along the shelf through SWs troughs; (2) fine- and coarse-grained TB currents, formed and entrained by the Primorsky current, intensified by the typhoons. This work presents the geological structure of the shelf area containing SWs. We established that the area of SWs location is on the border of change in facies conditions of sediment bedding in the bay. The transition from the inner shelf facies to the outer shelf facies occurs at a depth of 50–60 m. We analyzed the space variability of temperature and sound speed fields peculiar to the region on the results of hydrological CTD measurements and long-term measurements with moored vertical thermostrings. In the course of measurements, seven typhoons during their passage off the Primorye coast of the Russian Federation were registered. We found a significant change in the hydrological situation in the bay under the influence of extreme external factors. Under calm meteorological conditions, up to three mild thermoclines were observed in the bay, located at depths of 8–15 m, 30–35 m, and 45–60 m. During the passage of typhoons, they combined into one powerful thermocline at a depth of approximately 50–60 m, and in some cases, a high-gradient thermocline formed at the depths of 30–40 m (about 12–15 °C per 10 m of depth). The high-gradient layer significantly increases the amplitude and strength of internal gravity waves, thereby increasing the speed of currents in the water media. We should note that this period of transformation of the hydrological profile on the shelf under the influence of typhoons covers the period from August to October-November. We established that in the SWs location area, firstly, the process of internal waves disintegration intensifies in the autumn season, resulting in the formation of the waves with lengths close to the SWs horizontal scales (SWs wavelengths); secondly, under the influence of the typhoons entering the Sea of Japan, the kinetic energy of the shelf branch of the Primorsky current increases. In this case, it acts as a source of TB currents, including medium- and coarse-grained sedimentary material that forms SWs.

Hydrodynamic and hydrological processes within a variety of coral reef lagoons: field observations during six cyclonic seasons in New Caledonia

Abstract. From 2014 to 2021 during the cyclone seasons, extensive monitoring of the hydrodynamics within a variety of lagoons of New Caledonia was conducted as a part of the PRESENCE project (PRESsures on coral Ecosystems of New CalEdonia). The PRESENCE project is aimed at building an efficient representation of the land–lagoon–ocean continuum at Grande Terre, New Caledonia's main island. Overall, coastal physical observations encompassed five different lagoons (four of which were never before monitored) and at least eight major atmospheric events ranging from tropical depressions to category 4 cyclones. The main objectives of this study were to characterize the processes controlling the hydrodynamics and hydrology of these lagoons (e.g., ocean–lagoon exchanges, circulation, level dynamics, temperature, and salinity variability), and to capture the magnitude of change during extreme events. An additional objective was to compile an adequate data set for future use in high-resolution hydrodynamic models. Autonomous oceanographic instruments were moored at strategic locations to collect time series of temperature, salinity, pressure, and Eulerian currents. Additionally, Lagrangian surface currents were observed through deploying drifter buoys, and cross-shore hydrological profile radials were carried out using CTDs (conductivity, temperature, depth). In total, five survey campaigns were conducted, beginning with the SPHYNX campaign which lasted 15 months (December 2014 to February 2016) in the Hienghène–Touho lagoon and ended with the 9 months NEMO campaign (September 2020 to April 2021) in Moindou lagoon. Between these were the 5 months NOUMEA campaign (December 2016 to April 2017) in Noumea lagoon, the 6 months ELADE campaign (February to August 2018) in the Poe lagoon, and the 5 months CADHYAK campaign (December 2019 to May 2020) in Koumac lagoon. In addition to characterizing these lagoons, the data set identifies important features and processes, such as the presence of internal waves on forereefs, wave-driven fluxes over reef barriers, and exchanges through passes. Signatures from strong events were also identified, including surges, thermal drops inside lagoons, and massive flash flood plume dispersion. Raw data sets were processed, controlled for quality, validated, and analyzed. Processed files are made publicly available in dedicated repositories on the SEANOE marine data platform in NetCDF format. Links (DOI) of individual data sets are provided herein.

Coupling reconstruction of atmospheric hydrological profile and dry-up risk prediction in a typical lake basin in arid area of China

Arid area is very sensitive to global warming and are extremely vulnerable to climate change. Moreover, the water resources system in the arid area is fragile and will undergo tremendous changes with climate change. Therefore, the interaction of climate and hydrology in arid area has an important impact on the formation of regional microclimate and hydrological changes. Daihai Lake is a typical closed inland lake in arid area of China, and a key area for ecological protection in North China. In this paper, WRF-Hydro model is used to simulate the climate hydrological coupling situation of Daihai Basin from 1980 to 2020, and the coupling results are verified and calibrated by meteorological statistics, runoff calculation and remote sensing analysis. Based on the synopsis of climate and hydrology in the past 40 years, the causes and future trends of the hydrological elements in Daihai Basin are analyzed. Through the analysis, it is found that the interannual variation of precipitation in Daihai Basin is sharp, with 401.75 mm as the average from 1980 to 1994; and drastic fluctuations from 1995 to 2011, with a difference of nearly 400 mm between the interannual maximum and minimum; From 2012 to 2020, the fluctuation is small. Although the interannual variation of evaporation fluctuated, it showed an upward trend with a slope of 8.855 mm/year. The annual average temperature showed an obvious upward trend with a slope of 0.040 °C/year. From 1980 to 2020, the inflow of Daihai Lake shows a downward trend; Since 2013, the runoff into the lake has tended to be flat. Climate change and human activities are the decisive factors leading to the change of water quantity in Daihai, among which human activities play a greater role. Cultivated land irrigation and industrial water use are highly correlated with the lake discharge, and these two factors have a great influence on the lake discharge. If the current agricultural and industrial water consumption does not increase, Daihai still has a lifespan of nearly 120 years. If human activities do not change and any protective measures are not taken in time, under the background of global climate change, the flow of the Daihai Lake into the lake will be reduced to zero in 2025, and the Daihai Lake will completely dry up in 2031–2033. The study of climate hydrological coupling of long time series in Daihai Basin can not only make up for the lack of runoff data, but also provide the basis for water resources management, disaster prevention and mitigation.

ВИЙШОВ З ДРУКУ ПЕРШИЙ В УКРАЇНІ «ГІДРОЛОГІІЧНИЙ СЛОВНИК» (2022 р.)

The article presents and analyzes the explanatory “Hydrological Dictionary” published in 2022. Authors of the Dictionary: V.K. Khilchevskyi, V.V. Grebin (Taras Shevchenko National University of Kyiv), V.O. Manukalo (Ukrainian Hydrometeorological Institute of the State Emergency Service of Ukraine and the National Academy of Sciences of Ukraine). Hydrology is the science of the hydrosphere, which studies its properties, dynamics and interaction with other elements of the geographic envelope of the Earth. According to the objects under study, it is divided into hydrology. surface waters (or land hydrology), hydrology of oceans and seas (oceanology). In turn, the hydrology of surface waters is the hydrology of rivers (the study of rivers) and the hydrology of lakes (lake science or limnology). In water bodies, the following is studied: the dynamics of water masses (currents, waves, infiltration and other processes); dynamics of their bed (formation of banks and bottom of water bodies, channel processes, erosion, transport and sedimentation); thermal processes (heat exchange, heat balance, evaporation, water balance) and aggregate states of water (ice phenomena, snow cover), chemical and biological processes. The hydrology of groundwater (hydrogeology), the hydrology of soils, the hydrology of glaciers (glaciology) and the hydrology of swamps are also distinguished. Due to the commonality of the processes occurring in water bodies, along with the object-wise division of hydrology, it is often divided according to the processes studied into water dynamics, hydrophysics, hydrochemistry, and hydrobiology. Since these processes in each of the water bodies have their own characteristics, object disciplines have been developed in hydrology, including the study of a complex of issues in water dynamics, hydrophysics, hydrochemistry and hydrobiology. Since an ever wider range of specialists are involved in this area, including those who deal with the topical problem of the use, protection and reproduction of water resources, the issues of unification of hydrological terminology are becoming important. This goal is dedicated to the “Hydrological Dictionary”, which is the first in Ukraine scientific reference publication of this direction. The Dictionary includes more than 1600 terms and concepts that are widely used in the scientific literature on hydrology, as well as a number of terms in related scientific disciplines related to hydrology (hydrochemistry, geography, meteorology, geology, hydrogeology, hydrobiology, etc.). When working on the Dictionary, significant scientific and methodological experience of the scientific school of the Department of Hydrology and Hydroecology of the Faculty of Geography of Taras Shevchenko National University of Kyiv was used. The dictionary is designed for students of universities specializing in “Earth Sciences” of educational programs in the hydrological profile. The dictionary will be useful to specialists in the field of hydrology, hydroecology, hydrochemistry, hydrogeology, geography.

ВИЙШОВ З ДРУКУ ПЕРШИЙ В УКРАЇНІ «ГІДРОХІМІЧНИЙ СЛОВНИК» (2022 р.)

The article presents and analyzes the scientific reference publication – “Hydrochemical Dictionary”, published by the professor of the Kiev National Taras Shevchenko University V.K. Khilchevskyi in 2022. Hydrochemistry is a scientific discipline that studies the chemical composition of natural waters (surface, underground and marine) and the patterns of its change depending on chemical, physical and biological processes occurring in the environment and under the influence of anthropogenic factors. Hydrochemistry has its own object of study, a theoretical, methodological and methodological basis, which allows it to develop important scientific and practical issues. It is closely connected with hydrology, geology, oceanology, and hydrobiology. Being formed in the process of formation and further development, hydrochemistry is constantly enriched with new terms and concepts. Yes, since the early 2000s. hydrochemical and hydroecological terminology has been influenced by the Water Framework Directive (WFD) of the European Union due to the deepening of international scientific contacts and the implementation in Ukraine of the provisions of the WFD in regulatory documents. Since an ever wider range of specialists is involved in this area, the issues of unification of hydrochemical terminology are becoming important. This goal is dedicated to the “Hydrochemical Dictionary”, which is the first in Ukraine scientific reference publication of this direction. The Dictionary includes terms widely used in the scientific literature on hydrochemistry, as well as a number of terms in related scientific disciplines related to hydrochemistry (hydrology, geography, hydrogeology, hydrobiology, analytical, organic and physical chemistry, geochemistry, etc.), the EU WFD. The “Hydrochemical Dictionary” contains terms covering the following issues: properties and chemical composition of natural waters; processes of formation of the chemical composition of natural waters; methodology and methods of hydrochemical research and water analysis; processes of pollution and self-purification of water bodies; hydrobiological and microbiological processes in water bodies; water quality and integrated water resources management. The Dictionary contains about 830 terms and concepts listed in the subject index, which makes it easy to find the right terms on the corresponding pages. “Hydrochemical Dictionary” is designed for students of universities specializing in “Earth Sciences” of educational programs of the hydrological profile, studying hydrochemical and hydroecological disciplines; will be useful to specialists in the field of hydrochemistry, hydrology, hydroecology, hydrogeology, geography.

Mixing in the Tyrrhenian Interior Due to Thermohaline Staircases

Thermohaline staircases are a well-known peculiar feature of the Tyrrhenian Sea. Generated by extensive double diffusion processes fueled by lateral intrusions, they are considered to be the most stable of all the staircases that have been detected in the world ocean, seeing their persistence of more than 40 years in the literature. Double diffusion leads to efficient vertical mixing, potentially playing a significant role in guiding the diapycnal mixing. The present study investigates this process of mixing in the case of the Tyrrhenian staircases by calculating the heat and salt fluxes in their gradient zones (interfaces) and the resulting net fluxes in adjacent layers using hydrological profiles collected from 2003 to 2016 at a station in the heart of the basin interior. The staircases favor downward fluxes of heat and salt, and the results of the calculations show that these are greater where temperature and salinity gradients are also high. This condition is more frequently encountered at thin and sharp interfaces, which sometimes appear as substructures of the thicker interfaces of the staircases. These substructures are hot spots where vertical fluxes are further accentuated. Due to the increasing salt and heat content of the Levantine Intermediate Water (LIW) during the observation period, a rise in the values of the fluxes was noted in the portion of the water column below it down to about 1800 m. The data furthermore show that internal gravity waves can modulate the structure of the staircases and very likely contribute to the mixing, too, but the sampling frequency of the time series is too large to permit a proper assessment of these processes. It is shown that, at least during the period of observation, the fluxes due to salt fingers do not reach the bottom layer but remain within the staircases.

The new CNES-CLS18 global mean dynamic topography

Abstract. The mean dynamic topography (MDT) is a key reference surface for altimetry. It is needed for the calculation of the ocean absolute dynamic topography, and under the geostrophic approximation, the estimation of surface currents. CNES-CLS mean dynamic topography (MDT) solutions are calculated by merging information from altimeter data, GRACE, and GOCE gravity field and oceanographic in situ measurements (drifting buoy velocities, hydrological profiles). The objective of this paper is to present the newly updated CNES-CLS18 MDT. The main improvement compared to the previous CNES-CLS13 solution is the use of updated input datasets: the GOCO05S geoid model is used based on the complete GOCE mission (November 2009–October 2013) and 10.5 years of GRACE data, together with all drifting buoy velocities (SVP-type and Argo floats) and hydrological profiles (CORA database) available from 1993 to 2017 (instead of 1993–2012). The new solution also benefits from improved data processing (in particular a new wind-driven current model has been developed to extract the geostrophic component from the buoy velocities) and methodology (in particular the computation of the medium-scale GOCE-based MDT first guess has been revised). An evaluation of the new solution compared to the previous version and to other existing MDT solutions show significant improvements in both strong currents and coastal areas.

ПІДРУЧНИК «АГРОГІДРОХІМІЯ» (2021 р.) - ВНЕСОК У РЕАЛІЗАЦІЮ ПОЛОЖЕНЬ «НІТРАТНОЇ ДИРЕКТИВИ» 91/676/ЄEC В УКРАЇНІ

The article presents and analyzes the textbook “Agrohydrochemistry” (author V.K. Khilchevsky – professor of the Taras Shevchenko National University of Kyiv), published in 2021. The textbook examines the main problems associated with the growth of the chemicalization of agriculture and the protection of water resources. Due to agriculture, there is a noticeable impact on the quality of natural waters in the world, especially in regions of intensive agriculture, to which Ukraine belongs. Increased concentrations of nutrients and various types of pesticides are found in the waters of small and large rivers, groundwater. Therefore, the issues of studying the main sources of agricultural pollution of natural waters and the processes that contribute to this are relevant. Among the main sources of pollution of natural waters with wastewater, namely industrial, household and agricultural – the latter have a specific character of formation and flow into water bodies. If industrial and domestic wastewater is localized behind the formation and place of discharge into the sewer network, then the formation and supply of chemicals from agricultural land is dispersed throughout the catchment area and natural ways of entering (hydrographic network) into water bodies. The attention of the world community to the impact of agrochemicals on the quality of natural waters is evidenced by the Directive 91/676/EU adopted in the European Union of December 12, 1991 “On the protection of waters from pollution caused by nitrates from agricultural sources” (abbreviated as “Nitrogen Directive”), which in turn is a local manifestation of the integrating directive 2000/60/EC of October 23, 2000 “On the establishment of a framework for Community activities in the field of water policy” (abbreviated WFD – “EU Water Framework Directive”), aimed at achieving a good ecological state of natural waters in the regions river basins. Agrohydrochemistry is a direction in hydrochemistry that studies the effect of agrochemical agents on the chemical composition of natural waters using theoretical methods and the results of experimental studies in watersheds. The textbook, which consists of 9 chapters, gives an idea of the formation of the balance of chemicals in the soil, the use of various types of fertilizers and pesticides, and the possible ways of their entry into water bodies. Methods for calculating the flow of chemicals into water bodies are presented. The theoretical provisions are illustrated by the materials of our own research on the effect of agrochemicals on the chemical composition of river waters in the Dnieper basin. The textbook is designed for students of the specialty “Earth Sciences” of educational programs of the hydrological profile of higher educational institutions..

Hydrological drought in the Bohemian Forest region

The aim of this study was to select and apply appropriate methods for evaluating hydrological drought in the mountainous Bohemian Forest region. The results from individual hydrological profiles were compared with each other, followed by a general comparison of catchment areas in the extramontane region. The threshold and Gumbel (1963) methods, and a calculation of scarcity volumes, were used. In this way, dry days and episodes were defined, seasonal charts were compiled, and trends were assessed using the Mann–Kendall and Hirsch–Slack trend tests. It was found that the seasonality of the hydrological droughts on the windward and leeward sides of the mountains differed significantly. The maximum number of dry days was found to occur in the windward profiles in autumn and in the leeward profiles in winter. The amount of winter drought decreases with decreasing altitude. Significant decreases in the occurrence of hydrological drought were found in all profiles for the observed period.

EFFECT OF THE PANTANAL’S FLOODING HISTORY IN MORPHOMETRIC ASPECTS OF THE SOLITARY PARASITOID Campsomeris dorsata (HYMENOPTERA: SCOLIIDAE)

The shape of an organism and the variation between related groups lie at the core of understanding evolution and interactions between phenotypes, genotypes, and environmental spaces. Due to the relief conditions and hydrological profile of the region, the areas inside the Pantanal have different flood histories in respect to the flood duration and the amount of water retained in the plain. The objective of this work was to evaluate the effect of the environmental flooding gradient on the geometric morphometry variation of Campsomeris dorsata (Hymenoptera: Scoliidae) wings in Pantanal, to understand if the variations in spatial distribution related to the flooding history interferes in the morphology of the wings by identifying where, how, and to what magnitude such changes occur. The wings were mounted between blade and coverslip, labeled, and prepared for morphometric measurements. The points of intersection of wing veins (landmarks) were determined using a stereoscopic microscope coupled with a camera. The linear measurements of the landmarks were transformed using Procrustes to remove the size effect, leaving only the shape of the wings. The transformed data was evaluated using PCA and MANOVA to identify if there were differences in relation to the geographical location of occurrence. Thirty-three male C. dorsata wings were measured, and there was a clear separation between 3 distinct wing form groups along the Pantanal distribution. The variation in wing shape could be associated with selection from local environmental conditions in areas with distinct flooding histories, influencing migratory aspects among populations within the Brazilian Pantanal. The data for this small species, that has low dispersal capacity, is solitary, and presents an intimate relationship with soil characteristics, which directly reflects flooding aspects in the Pantanal, only reinforces the need to conserve more areas in the Brazilian Pantanal, since genetic diversity is an important factor for conservation.

A novel estimation method for SPM in China eastern coastal waters based on conventional hydrological profile measurements

Suspended particulate matter concentration (SPM) in coastal waters is of great importance for studying sediment resuspension and sediment transportation, especially for the profile distribution in bodies of water. The traditional SPM profile-obtaining method that uses a turbidity meter introduces large uncertainty for pigment particle-dominated waters. This research used a large amount of profile data on optical properties and hydrological measurements parameters (conductivity-temperature-depth (CTD), chlorophyll and turbidity), which were measured synchronously in the Bohai Sea and Yellow Sea; the data were used to analyze the relationships between the vertical distribution of the particulate backscattering ratio and the vertical distribution of pycnocline, chlorophyll and turbidity and to distinguish pigment particles and sediment particles in the vertical distribution. After considering the particle types, we also developed a novel method that exclusively depended on conventional hydrological measurements. The results show that the new method is simplified and effective and could significantly improve the accuracy of SPM estimations in coastal waters.

ДОЛГОВРЕМЕННАЯ ИЗМЕНЧИВОСТЬ ТЕЧЕНИЙ В ЗОНЕ СУБАРКТИЧЕСКОГО ФРОНТА АТЛАНТИЧЕСКОГО ОКЕАНА

Based on time series of near-bottom current velocities and temperatures obtained in the period June, 2016 to July, 2017, at three points in the Atlantic Subarctic Front, along with the use of multi-year (since 1993 up to now) satellite ocean surface sounding data, multi-scale fluctuations of ocean surface and near-bottom flows over the western and eastern flanks of the Reykjanes ridge, as well as near Hatton Rise, on the Rokoll plateau, are studied. Hydrological profiles were carried out from the ocean surface to the bottom with readings every 10 m, when setting and retrieving the buoy stations. Using data from the Bank of hydrological stations (WOD13), SST satellite arrays (Pathfinder), long-term sea level and geostrophic velocities time series (AVISO), and bottom topography (model ETOPO-1), features of longterm cyclical fluctuations of SST, sea level, geostrophic currents on the ocean surface were defined in the sub-polar North Atlantic. It is shown that, in accordance with the large-scale thermohaline structure of the Subarctic front, two branches of the North Atlantic Current are detected on the ocean surface.One is directed from the Hatton towards the Icelandic-Faroese Rise, and the other – alomg the western flank of the Reykjanes Ridge toward Iceland. For the first branch, which is the main continuation of the North Atlantic Current, the average (for 25 years) water drift at a speed of 9.1±0.1 cm/s is determined to the northeast. The second branch, which forms the eastern part of the Subarctic cyclonic gyre, has the average water drift at a speed of 4.0±0.1 cm/s is directed north-northeast, along the western flank of the Reykjanes Ridge. In the intermediate waters of the frontal zone, an average water flow is observed at a speed of 2.7±0.1 cm/s to the north-northeast, along the eastern slope of the Reykjanes ridge.Due to the multy-scale components of the total variability, the average kinetic energy densities(KED) of total currents (109, 45, 97, (±3) erg/cm3, at station points from east to west) are much greater than the mean drift KED. The near-bottom flows on the Reykjanes ridge flanks are opposite to the direction of the North Atlantic Current. Outside the Subarctic gyre, the direction of average transport is maintained from the ocean surface to the bottom. The average (per year) KED of near-bottom currents are 31, 143, 27 (±3 erg/cm3), for three stations from east to west, respectively. In the intermediate waters of the frontal zone, above the eastern slope of the Reykjanes Ridge, there is a powerful reverse (relative to the North Atlantic Current) near-bottom water flow to the south-west, with a high average speed of ~ 15 cm/s. The KED of the currents during the year varies widely from zero to ~ 600 erg/cm3. The overall variability is due to cyclical variations and intermittency (“flashes”) of currents. Perennial cycles, seasonal variations, synoptic fluctuations with periods in the range of 30–300 days, as well as inertial oscillations and semi-diurnal tidal waves are distinguished. The intermittency of oscillations is partly due to changes in low-frequency flows, which can lead to a dopler frequency shift in the cyclic components of the spectrum. The amplitude of temperature fluctuations in the bottom layer for the year was (0.07–0.10) ± 0.01°C by the standard deviation. The seasonal changes of the bottom temperature are not detected. However, a linear trend with a warming of ~ (0.10–0.15) ± 0.01°С per year is noticeable.

Tides and Turbulent Mixing in the North of Taiwan Island

Microstructure and hydrological profiles were collected along two cross-shelf sections from the deep slope to the shallow water in the north of Taiwan Island in the summer of 2006. While the tidal currents on the shelf were dominated by the barotropic tide with the current ellipse stretched across the shelf, significant internal tides were observed on the slope. The depth-mean turbulent kinetic energy (TKE) dissipation rate on the shelf was 10−6 W kg−1, corresponding to a diapycnal diffusivity of 10−2 m2 s−1. The depth-mean TKE dissipation rate on the slope was 1×10−7 Wkg−1, with diapycnal diffusivity of 3.4×10−4 m2 s−1. The shear instability associated with internal tides largely contributed to the TKE dissipation rate on the slope from the surface to 150 m, while the enhanced turbulence on the shelf was dominated by tidal or residual current dissipations caused by friction in the thick bottom boundary layer (BBL). In the BBL, the Ekman currents associated with the northeastward Taiwan Warm Current were identified, showing a near-bottom velocity spiral, which agreed well with the analytical bottom Ekman solution.

«РЕГІОНАЛЬНА ГІДРОХІМІЯ УКРАЇНИ» (2019) – СУЧАСНИЙ ПІДРУЧНИК З ВИВЧЕННЯ ХІМІЧНОГО СКЛАДУ ПОВЕРХНЕВИХ, ПІДЗЕМНИХ І МОРСЬКИХ ВОД НА ТЕРИТОРІЇ КРАЇНИ

The article reviewed and analyzed the textbook “Regional Hydrochemistry of Ukraine” (authors V.K. Khilchevskyi, V.I. Osadchyi, S.M. Kurylo), published in 2019. The textbook comprehensively summarizes and covers materials on the hydrochemistry of precipitation, rivers, lakes, reservoirs and ponds, underground and sea waters in Ukraine. The authors used the latest results of studies of the chemical composition of water of various water bodies in the country, applied the hydrochemical characteristics of the river basin districts according to the modern hydrographic zoning of Ukraine (2016), which takes into account the requirements of the European Union Water Framework Directive (WFD 2000/60/EC). A feature of the textbook is that the authors were largely based on the materials of their own studies of the chemical composition of surface waters. They also systematized and generalized the monographic works of leading Ukrainian scientists, in different years (from the 1950s to the present day) they studied fundamental and applied issues of hydrochemistry of surface, underground and sea waters. The structure of the textbook consists of a preface, 11 sections, applications and a list of references. The textbook is intended for students of the specialty “Earth Sciences”, studying in educational programs of hydrological, hydroecological and hydrogeological profile. It may be useful for students of the specialty “Geography”, students in educational programs of a physical-geographical and geo-ecological profile.

Living in the Extremes: The Thermal Ecology of Communal Nests of the Highland Andean Lizard Anadia bogotensis (Squamata: Gymnophthalmidae)

Nesting in tropical highlands is challenging due to the fluctuations of temperature, including extreme cold, and humidity. For most reptiles in the highland tropical region the thermal and hydrological profiles of nests have not been described, and it is therefore uncertain how future climate change may affect this ontogenetic stage. We monitored 17 communal nests of Anadia bogotensis at a highland locality in Colombia. The soil humidity and temperature of the nests and the air temperature were recorded for almost a year, together with other physical and biotic nest characteristics. Nests exhibited high temporal and spatial thermal variation unrelated to the nests' physical characteristics. The maximum and minimum temperatures of the nests and air exhibited a linear and positive relationship, whereas the thermal variance (CV) exhibited a linear and positive relationship with maximum air temperature. Furthermore, CV of the heating phase was higher than that of the cooling phase for the nest and air temperature and it was similar between nests with and without viable eggs. However, it was different between each nest type and air temperature. During the cooling phase the average CV was different between nests with and without viable eggs and between nests and air temperature. In conclusion, the temperature of the nests exhibits strong daily fluctuation, and most of the nests follow the same fluctuation as air temperature. However, it seems that the rock covering some nests prevents the nest temperature from falling as quickly as the air temperature and from reaching the minimum environmental value.

HIGH FLOWS FROM GORNJA DOBRA BASIN

The paper presents basic hydrological indicators based on data from the four existing hydrological stations on the Gornja Dobra basin. The frequency and flow-duration curves of mean daily flow in Turkovici profile are also defined and presented. The dependence of the mean maximum annual specific flows on the size of the influential basin to the considered hydrological profiles was considered. A review of a most recent high water event in 2017 was given.

Characteristics of multi-annual variation of precipitation in areas particularly exposed to extreme phenomena. Part 2. The upper and middle Oder river basin

The study contains an analysis of precipitation, covering multiple profiles and based on the GPCC database that provides monthly mean values for the territory upper and middle Oder catchment. The analysis includes data for the period 1901-2010 with a spatial resolution of 0.5° ×°0.5° of geographic longitude and latitude. The following sections include a data analysis in monthly profiles and hydrological cycle profiles, taking into account hydrological summer and hydrological winter. A cluster analysis is also included, with drought and flood periods indicated. The periodical nature of precipitation is assessed and the trends in climate changes calculated.