Ukrainian hydrometeorological journal

Validation of precipitation obtained from GPM and H-SAF satellite data with relation to Ukrainian ground weather stations' data

O. S. Zabolotna — 2023-12-27

The main objective of this study is to validate H-SAF and GPM satellite precipitation data for the territory of Ukraine. Validation was carried out by comparing satellite data with data from ground weather stations of Ukrainian Hydrometeorological Center and included the following stages: data collection and processing, bringing the data to the same spatial and temporal resolution, calculation of correlation coefficients and construction of confusion matrices. Correlation coefficients were calculated for each of the stations for two studied periods (the first period - April-September 2020, the second period - April-September 2021). In addition, to ensure a more detailed analysis, confusion matrices were constructed based on division of precipitation into classes of different intensity. The comparative analysis showed that a larger number of stations (117) has a correlation coefficient of 0.5 - 0.8 with relation to GPM data, and, as for HSAF precipitation data, a larger number of stations (59) has a low correlation coefficient (0 - 0.3). Confusion matrices were calculated for the following four classes of rainfalls (mm): “0-2”, “2-5”, “5-10”, “>10”. The confusion matrices coefficients showed that low-intensity precipitation or “no precipitation”, as well as high-intensity precipitation, can be determined by a satellite with high accuracy as opposed to the ground-based weather station measurements. Thus, according to the "specificity" indicator, a precipitation class >10 mm has the highest level of correspondence of satellite data (H-SAF, GPM Late, GPM Early) to ground data. The low value of the "specificity" for the range of 0-2 mm is explained by the fact that satellite methods are able to detect very low values of precipitation intensity, while the station shows their absence – 0 mm. Thus, according to the values of the confusion matrices, we see that a large part of the values of ground measurements of precipitation in the range of 0-2 mm are shown by the satellite method as “2-5 mm” class. We can also see that the “2-5 mm” class by satellite has the most confusion with the 0-2 mm class by station (for H-SAF, GPM Late, GPM Early). But based on the high values of the "recall" for the range of 0-2 mm (for H-SAF, GPM Late, GPM Early), we can conclude that when the station does not show this amount of precipitation (0-2 mm), then the satellite also shows another class of values. The values of "precision" coefficient show that the satellite measurements are actually reliable. This means that presence or absence of precipitation may be determined precisely, since the highest value of the "precision" coefficient is typical for low and high amounts of precipitation (on average 0.76 and 0.66, respectively). Detected by satellites, heavy precipitation or no precipitation are also confirmed in most cases by ground stations. Based on the results of the validation, GPM and H-SAF satellite precipitation data products can be used for rainfall monitoring and considered as an additional source of meteorological information.

Classification of synoptic processes in the territory of Ukraine using a modified Jenkinson and Collison method

I. G. Semenova — 2023-12-27

During the year, the territory of Ukraine is under the influence of various synoptic processes, which have a certain evolution in the surface conditions of the region and sometimes lead to the formation of unfavorable and dangerous weather conditions. The classification of synoptic processes makes it possible to create a set of daily synoptic situations taking into account the characteristics of a certain region, both for their use in weather forecasting and for studying the dynamics of regional synoptic processes under climate change. In this study, the modified version of Jenkinson and Collison method is used to classify synoptic processes on the territory of Ukraine, which is based on pressure data at the sea surface level and the geopotential heights at the level 500 hPa. The analysis of the obtained set of daily types of atmospheric circulation for the period 1948-2021 and the composite pressure fields built for each circulation type showed that all synoptic situations are clearly defined according to the classification and have seasonal features of frequency. During the year, advective processes of the western circulation group prevail, eastern advection is also often observed, and this type of circulation dominates in the spring months. The processes of the southern group are most relevant on the cold period of the year. Anticyclones occur more often over the region in winter and autumn, and cyclones are observed in summer and spring. The inclusion of 500 hPa level data in the classification makes it possible to take into account the three-dimensional structure of synoptic objects and distinguish such types of circulation as low cyclones and cold anticyclones, as well as troughs and cut-off lows at heights. It was found that low (thermal) cyclones and anticyclones make up a small proportionof synoptic situations, so the feasibility of their further inclusion in the typification for the territory of Ukraine is being discussed. The processes associated with the cut-off lows at the upper levels turned out to quite rare, but due to the possibility of the formation of dangerous weather conditions, this type of circulation is necessary in the classification of regional synoptic processes.

Environmental risks assessment of the Kogylnyk River nutrient pollution based on probit functions

N. S. Loboda — 2023-12-27

The relevance of the study is associated with the need to determine the risks of high and catastrophic levels of water pollution of the Kogylnyk River. The water quality of this river affects the environmental condition of the northern part of Sasyk lake and reservoir. This artificial reservoir that was created as part of the estuary used to be one of components of the Danube-Dniester irrigation system in the past and can be used for irrigation in the post-war period in the future. As the North-Western Black Sea region is an agricultural region of Ukraine, the article focuses on the pollution of the river by specific nutrients (ammonium, nitrite, nitrate, phosphate). The subject of the study covers the environmental risks assessment of the Kogylnyk River present-day pollution. Hydrochemical observations of the State Water Resources Agency of Ukraine were used as input materials of the research. Such observations were carried out across the upper (below the border with the Republic of Moldova) and lower sections of the river. The number of samples taken in the upper section was 80, and 56 – in the lower section. Water quality was assessed using a modified water pollution index (WPI). The risks of nutrient pollution were evaluated based on a statistical approach using a probit function. It was found that the water quality in the upper section is worse than the one in the lower section. The research indicated a close correspondence between water quality indicators and environmental risk values. In the upper section, the risks of catastrophic pollution have a probability of their occurrence that is equal to 46.1%, and the risks of high pollution – 41.1%, with 87.2% constituting a total percentage. In the lower section, the probability of a high level pollution risk is equal to 33.3%, with no critical risk identified during the observation period. The trophic status of the water body along the river length varies from hypertrophic and polytrophic on the upper course to eutrophic and mesotrophic on the lower course. The decrease in pollution levels in the river's lower section is due to the processes of biological, physical and chemical self-purification of the aquatic ecosystem. Since nutrients have a predominantly anthropogenic origin, the water quality improvement of the Kogylnyk River across the territory of Ukraine is associated with the reduced flow of municipal and agricultural wastewater entering the river. Nutrient pollution requires implementation of additional measures such as improving the culture of farming taking place in the catchment area (for example, during conservation of fertilizers and their application).

Patterns of runoff fluctuations of the Dniester River (Ukraine) under conditions of climate change at the beginning of the 21st century

N. S. Loboda — 2023-12-27

The relevance of the chosen topic is associated with the impact of climate change on fluctuations of water content in Ukrainian rivers. The consequences of warming depend on physical and geographical conditions and vary significantly across different natural zones. The behaviour of catchment areas affected by climate change varies depending on landscape (mountainous or flat terrain) and latitude. This results in instability of boundaries of catchment areas with annual runoff synchronous and out-of-phase fluctuations. The study aims at establishing the patterns of annual runoff fluctuations in the Dniester basin with relation to fluctuations in the maximum runoff of rainfalls and spring floods. The spring floods are the ones that determine a significant part of annual runoff and depend on the impact of warming during the winter season. The study's main method is the method of constructing difference integral curves of annual and maximum rainfalls and maximum spring runoff and their analysis. There are 7 groups (zones) within the Dniester River catchment area identified by the type of difference integral curves of annual runoff. Fluctuations in annual, maximum rain and spring runoff were compared using the curves averaged within each group. The degree of synchronicity of fluctuations was estimated via correlation coefficients between the ordinates of difference integral curves. It was found that the main river oscillations retain their cyclicity along its entire length, even below the Dniester HPP. The last transition to a low-water phase occurred in 2010-2011. It was discovered that the main river's cyclical nature mostly results from fluctuations in the runoff of mountainous Carpathian tributaries that form the Dniester's runoff formation zone. This part of the catchment area is characterized by a high amount of snow and rainfalls feeding the river with the role of rainfalls having a predominant character. In the upper reaches of Carpathian rivers, where the impact of warming is not yet sufficiently pronounced at high altitudes, spring floods play a significant role in runoff formation. In the upper reaches of Carpathian rivers there is an additional zone where fluctuations in annual runoff are caused by both rainfalls and spring floods. The boundaries of this zone (2nd district) may change as the effects of warming increase high in the mountains. On the left-bank tributaries, the runoff fluctuations in Verkhnepodilskyi and Serednepodilskyi districts are similar to those of the main river, however, there is a shift in the dates of the last transition to a low-water phase. The study indicates the likelihood of karst and artificial reservoirs influence. It also indicates a significant difference in the nature of runoff fluctuations of the upper left-bank tributaries (Strvyazh, Vereshchytsia, Shcherek) and lower left-bank tributaries. They are affected by other atmospheric processes and climatic factors associated with such processes.

Average condition and seasonal variability of the structure and dynamics of transitional waters in the Dnieper-Bug estuary region

Yu. P. Ilyin — 2023-12-27

Based on the data of long-term coastal and expeditionary observations, the structure and dynamics of transitional waters in the system of the Dnieper-Bug estuary (the DBE) before the destruction of the Kakhovka HPP are considered as the basis for the future description of changes in the hydrological regime. Average annual and seasonal maps and vertical sections of temperature and salinity are drafted. The article analyzes the main factors of formation and distribution of transitional waters such as river runoff, salinity (density) contrast and surface wind. A number of dimensional and dimensionless criteria and indicators of the transitional water dynamics within and outside the DBE are calculated and analyzed.

The analysis of previous studies of river water transformation in the North-Western part of the Black Sea (NWBS) and dynamics of floating plumes in other areas of the World Ocean's coastal zone allows us to establish a 14 P.S.U. isohaline as the outer limit for transitional waters of the NWBS.

According to the monitoring data of 1992-2020, the highest degree of desalination of the DBE and output of transition water from the Kinburn Strait was observed in spring, under the conditions of increasing volume of river runoff and predominant wind from the east. At the same time, the increasing repeatability of the south wind contributed to pushing the plume towards the coastal area outside the estuary. In summer, the influence of open sea waters on the DBE increased due to decreasing river runoff and increasing frequency of westerly winds.

According to theoretical criteria, under low-wind conditions, the estuary produces a surface-advective plume affected by buoyancy and Coriolis force, with no effect of friction in the bottom boundary layer. The distance over which such plume spreads, even in summer, does not exceed half way from the Kinburn Strait to the Odesa Bay. The ingress thereto of transitional waters of the DBE in spring and autumn can be facilitated by accompanying wind currents.

The main factor of the plume's summer dynamics includes both westerly wind and the currents it generates. The latter prevent the spread of transitional waters to the west along the coast, pushing them towards the estuary and to the south off it. This does not negate the possibility of a different plume behavior due to the increasing volume of river runoff and synoptic variability of the wind field during certain years and months.

Interannual variability of ice cover across Davis Strait and the Labrador Sea for the period from 1979 to 2023

Е. Maliuha — 2023-12-27

In conditions of rapid development of trade and transport communications, the issue of navigation through ice regime zones became of greater importance. In particular, reduction of the area of ice cover in the Canadian Arctic because of global warming opens up favourable prospects for further development of maritime shipping in this zone. Considering that the routes through the Northwest Passage are the shortest ones of all the routes connecting the Atlantic and Pacific oceans, it is clear that all aspects of this topic are of great importance and relevance. This especially applies to the aspects dedicated to studying the characteristics of appearance, formation, concentration, physical characteristics, trajectory of ice movement and forecasting the area of the ice cover in a given zone, i.e. the characteristics affecting the conditions of ice navigation and serving as determining factors in terms of navigation safety.

The research examines some of these issues, namely the spread of the ice cover during the period of its maximum formation across Davis Strait and the Labrador Sea (where the routes through the Northwest Passage start) and the establishment of statistical relations between the ice spread and the temperatures of surface water and surface air. The research method to be used: synoptic-climatic and statistical analysis of numerical series of ice cover deviations from its average limit as of April 15 over the period of 1979-2023 within the zone in study.

Based on the set goal, the study processed raw data on distribution of ice cover across Davis Strait and the Labrador Sea for the period of 1979-2023 and completed its statistical analysis. The results of the analysis showed presence of a statistically significant negative trend and cyclical fluctuations with periods of 3-6, 9, 10 and 13 years in relation to the interannual variability of ice cover distribution for the studied period. Positive trends are also observed in the interannual variability of surface water temperature and surface air temperature. After bringing the original series to a quasi-stationary form, a correlation analysis of the relationships between the ice cover distribution and the temperature of water and air was carried out. The results of the analysis determined zones and points with statistically significant correlation coefficients between them during the year. It turned out that the highest values of coefficients are observed from December to March, and the maximum one occurs in March.

Systematization and analysis of the ice field across Davis Strait and the Labrador Sea during the period of maximum development made it possible to establish that the spread of ice between 60° and 55° north parallels was the most stable during the studied period, and the least stable was observed in the area below 55° north parallel.

The results of the conducted research open up prospects for development of methods for forecasting the distribution of ice cover across Davis Strait and the Labrador Sea. This will make ice navigation in this area safer.

Characteristics of Black Sea dispersion of freshened and polluted transitional waters from the Dnipro-Bug estuary after destruction of the Kakhovka Reservoir dam

Yu. S. Tuchkovenko — 2023-12-27

This study examines the characteristics of distribution of large volumes of freshened and polluted transitional waters from the Dnipro-Bug estuary across the northwestern part of the Black Sea (NWBS) that was caused by destruction of the Kakhovka HPP dam in June 2023. From June 6, 2023 to June 12, 2023 14.4 km³ of water were discharged from the Kakhovka Reservoir into the Dnipro-Bug estuary and subsequently into the sea. This volume constitutes 27% of the total annual average natural runoff of the Dnipro River (53.5 km³). During the initial days following the dam destruction water flow through the breach amounted to 40-50 thousand m³/s. The water carried a variety of pollutants into the sea that were present in the water of the Kakhovka Reservoir, in its bottom sediments, and also washed off from the flooded territories of the lower Dnipro area (more than 2000 hectares).

The analysis of the distribution characteristics was conducted using satellite images of the sea surface color and chlorophyll a concentrations, as well as the results of hydrodynamic modeling with application of the 3-D variant of a numerical hydrodynamic model Delft3D-Flow Flexible Mesh. It was established that the plume of freshened and polluted water initially spread across the Dnipro-Bug estuarine region of the NWBS and then moved towards the sea coast of Odesa reaching it on June 9-10, 2023. Subsequently, the plume began to spread along the western sea coast and reached the Tuzlivski Limans area on June 14, 2023. After this the narrow plume of dispersed water along the sea coast began to dilute when moving towards the open sea in the form of "tongues" that had formed over the sea bottom elevations. The modeling of dispersion of a conservative neutral buoyancy admixture serving as a marker of pollution spread with the transitional waters from the Dnipro-Bug estuary showed that reduction in pollution levels took place solely due to hydrodynamic dilution (up to 60% in Odesa District of the NWBS and up to 30% in the Danube-Dniester interfluve area of the river water pollution level observed in Kherson).

The identified characteristics were determined based on the water circulation process that formed in the Dnipro-Bug estuarine area under the influence of significant sea level gradients resulting from the inflow of large volumes of freshened transitional waters through the estuary and the Kinburn Strait during the first days, and then followed by the density currents formed at the hydrofront between the transformed river water and surrounding sea. The influence of wind conditions manifested itself in the form of spread across the NWBS of the plume of dispersed transitional water from the Dnipro-Bug estuary and the hydrofront's position and configuration. Though wind-induced currents were not dominant, they still influenced the water dynamics and distribution of concentrations of admixtures, for instance, chlorophyll a, within the freshened plume that was outlined by the hydrofront. They also promoted penetration along the coastal shallow area of transformed river water towards Odesa.

Biogeochemical lichen indication study of formation and temporal changes of Oleksandriia Arboretum atmospheric pollution

O. V. Shabatura — 2023-12-27

Using the method of biogeochemical lichen indication the levels of the average long-term content of K, Ca, Al, Fe, Mg, Na, Mn, Zn, Sr, Ti, Ba Cu, B, Pb, Ni, V, Cr, Co, Cd, Se, Sb in surface air were measured on the territory of Olexandriia Arboretum and adjacent territories (Bila Tserkva, Kyiv Region, Ukraine). The purpose of the study is to determine the state and dynamics of the atmospheric geochemical field on the territory of Olexandriia Arboretum and its surroundings. The method of biogeochemical lichen indication based on the values of micro- and macroelements content in epiphytic lichens was used as a research tool. Application of the ICP-OES spectroscopy method allowed the analysis for chemical elements content of the samples of epiphytic deciduous Parmelia sulcata, Xanthoria parietina and bushy Evernia prunastri lichens collected in 2009 (20 points) and 2021 (23 points).

In order to identify possible sources of entering of certain elements into lichens the researchers used the factor analysis method, i.e. a method of principal components with Varimax factors rotation. Six obtained factors represent: the impact of land cover (the most significant factors F₁–F₃) and man-made components (minor polygenetic, factors F₄–F₆). As a factor's number decreases, its partial explanatory variance decreases too. Factor F₁ represents a common dust loading on the atmosphere with a predominance of the terrigenous component (mostly coarse-dispersed particles). Factor F₁ is responsible for the dust-aerosol loading that is largely caused by the microclimatic circulation of the city breeze type thus forming a peculiar atmospheric and geochemical association that consists of chemical elements related to the building industry and building materials production. Powerful, however, local (impactful) atmospheric man-made influences manifest themselves through factor F₃. Minor factors' discrimination ability reduces if a source of atmospheric pollution is less significant. Both division of factors into subfactors and noticeable temporal dynamics are observed more often. For instance, factor F₄ has two geochemical sub-associations affected by the impact on the Olexandriia's landscapes of the 1990s' ecological disaster (fall-out of oil products, geochemical marker – V) and galvanic waste causing soil pollution (Zn, Mg, Cr, Ni and Ti), as well as discharges of agricultural enterprises (K). One of the peculiarities of F₄ is a gradual decrease in its intensity over time. Factor F₅ should be interpreted as the only load on the environment associated with galvanic pollution with cobalt being replaced by copper as a leading pollution marker. We suggest considering Factor F₆ as a factor associated with oil pollution only.

Status of atmospheric air pollution in Ukraine prior to the full-scale russian invasion. Part 2: Pollutants total content according to the satellite data

M. V. Savenets — 2023-12-27

The paper describes the main features of pollutant total content distribution over Ukraine that can be used as baseline air quality data observed before the full-scale russian invasion in Ukraine. The study is based on the data derived from the TROPOspheric Monitoring Instrument (TROPOMI) onboard of the Sentinel-5 Precursor (5P) satellite that indicates nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO) and formaldehyde (CH2O) levels. We defined the characteristics of pollutants spatial distribution with full coverage of Ukrainian territory. Despite the increasing role of automotive emissions, the most polluted air in Ukraine was still observed over large industrial cities and smaller settlements having the biggest thermal power plants (TPP). The high level of pollutants content over these locations negatively affects air quality in suburban and rural areas by the prevailing wind. They form relatively stable polluted spots over larger areas. Hence, main polluted areas include: Donetsk Region; territories in the central part of Ukraine along the Dnipro River and near the destroyed Kakhovka reservoir; Kharkiv and Zmiiv TPPs; Kyiv and Trypillia TPPs; and the territories in the western part, including Lviv, Dobrotvir and Burshtyn TPPs. The polluted air from these territories determines the air quality depending on a prevailing wind. In case of high wind speeds polluted air can be distributed from urban areas towards relatively clean territories such as Carpathian and Crimean Mountains, northern Polissia, and the Medobory National Park of Podillia. We determined quantitative parameters of wind speed and direction for every pollutant that causes higher total content over relatively clean territories. Pollutants dispersion in the atmosphere varies depending on a boundary layer height (BLH). It was found that NO2, CO and SO2 content significantly increased when the BLH was below 500 m over both urban areas and clean territories with no emission sources available. The inverse dependence on the BLH was identified for CH2O. This can be explained by a more intense photochemical production at higher altitudes. The detected baseline air pollution conditions can be used in order to assess the impact of the war on air quality in Ukraine and come up with relevant post-war development measures.

Resource potential of municipal solid waste in Odesa Region

T. A. Safranov — 2023-12-27

Despite the widespread use of the term "municipal solid waste" (MSW), the main regulatory and legislative documents of Ukraine use the term "household waste". International practice also does not have a clear definition of the "municipal solid waste" concept, however, there are a number of related terms. Municipal solid waste is defined as a waste that is generated in the course of human activity, accumulated in residential buildings and social institutions and considered as unsuitable for further use at places of its generation. As for the related terms used in foreign and national practice, the term “household waste”, i.e. waste generated directly by households, is more appropriate. Municipal solid waste is a heterogeneous mixture that has a complex waste composition and its quantitative and qualitative characteristics are not constant and depend on characteristics of a certain country, region, city or town where it was generated, season and other factors. Growing volumes of municipal solid waste is one of the components of growing anthropogenic load that poses a threat to environmental safety of the country's regions and public health and negatively affects the state of our environment. The main methods of such solid waste management in Ukraine include landfilling, incineration, recycling and recovery. Out of the total annual waste volume generated on the post-Soviet territories, 93% are taken to landfills or dumpsites, 4% – incinerated, and only about 3% – recycled.

Therefore, creation and implementation of an effective system of solid waste management is an important task for ensuring environmental safety and sustainable development of the country's regions. Moreover, solid waste is a significant reserve for obtaining secondary material resources. According to the circular economy concept, almost all components of solid waste should be reused for production of new items. This will minimize negative impact on the environment and allow rational use of natural resources. The article analyses the current state of municipal solid waste management system in Odesa Region and assesses resource value of such waste. Secondary raw materials worth of almost UAH 1.4 million can be produced annually from the total flow of municipal solid waste in Odesa Region. And this figure does not take into account liquidity of food and other waste. After establishing an effective food and other organic waste management system, such amount may be significantly increased. Separation of resource-value components from the total solid waste flow and their subsequent use will help to reduce technogenic load on the environmental natural components and improve the overall environmental situation in Odesa Region.