- No. 2(4) 2023
«Meteorology. Hydrology. Environmental monitoring»
“CHANGES IN ATMOSPHERIC AIR POLLUTION AND FUEL COMBUSTION EFFICIENCY IN UKRAINIAN CITIES DUE TO MILITARY ACTIONS
The full-scale russian invasion of Ukraine significantly changed atmospheric air pollution in Ukrainian cities. Most changes can be identified using only remote sensing data due to its spatial coverage. In the presented paper, we perform the analysis of war impacts on nitrogen dioxide (NO2) and carbon monoxide (CO) spatial distribution derived from the TROPOsphericMOnitoring Instrument (TROPOMI) of the Sentinel-5 Precursor (S5P) satellite data for the period of January 2021 – May 2023. Based on their content in polluted plumes over the city and in the background, the parameter dNO2/dСО for burning efficiency assessment was calculated and processed. The overall decrease in NO2 and CO content was detected in the cities, reaching 6-34% and 9-17%, respectively. In comparison to background content, the NO2 drop in cities was more significant. At the same time, CO decreased by 2-3% more in the background than over the cities (except Mariupol, where Azovstal was totally destroyed). Since the full-scale hostilities have started, total NO2 content began redistributing seasonally and its summer maxima started to appear in the majority of cities. Starting from the period of regular drone and missile attacks on energy infrastructure, background NO2 significantly decreased, showing a regional response. CO total content has changed mostly homogeneously over the entire studied domain. There were no seasonal shifts or dependencies during the period of war. Using the four parameters mentioned, we estimated burning efficiency changes based on the dNO2/dСО parameter. It allowed us to detect possible changes in fuel use. Overall, dNO2/dСО decreased by 11-46% which indirectly proved the increase in solid or “dirty” fuel use and less gas consumption. Burning efficiency dropped immediately after the full-scale invasion started, becoming more sensitive to pollutants content in the plume. The consideration of the researched parameters is important for making new atmospheric air quality management plans in cities, rebuilding damaged infrastructure, and creating emission inventories during the wartime.
“POPULATION MIGRATION AS A PRESSURE IMPACT FACTOR ON THE STATUS OF SURFACE WATERS CAUSED BY RUSSIAN AGGRESSION AGAINST UKRAINE
The full-scale invasion of Ukraine by russian troops has caused massive population displacement. The International Organization for Migration noted that the number of officially registered internally displaced persons is 38% of the total number of refugees. The abrupt migration of population to the western regions of Ukraine has created an additional burden within the river basins. The priority migration destination was cities, while others dispersed to rural areas. In the first case, population growth led to an additional load on the municipal infrastructure and increased the impact of point sources on river ecosystems. In the second case, it has created conditions for an increasing of diffuse pollution. The results of water utilities reporting in the western regions of Ukraine (by the 2TP-Vodhosp form) indicate the rising in 2022of wastewater discharge compared to the volume in 2021. Based on the analysis of organic substances (BOD5 and COD) and nutrients (ammonium nitrogen and phosphorus), a significant increase in their content was revealed for rivers in the Vistula basin, the upper and middle parts of the Dniester basin, sub-basins of the Danube (Tisza, Prut, and Siret rivers). These substances are formed as a result of the vital activity of living organisms and are protein in nature, which makes them characteristic indicators of municipal wastewater. By calculating the mass balance, it was shown that in Lviv, the load of ammonium nitrogen increased to about 67 tons per year, and phosphorus - 31 tons per year. The relative share of the load from point sources reached 37% and 87%, respectively. The average impact of point sources due to military actions was 8.3% for nitrogen compounds and 7.5% for phosphorus compounds. Against this background, the content of nitrate nitrogen compounds, which are formed mainly by diffuse sources, decreased. Most of the small rivers in the western region of Ukraine had deviations from the 'good' ecological status. The reason for this was a small natural flow, which does not allow for effective dilution of insufficiently treated wastewater from municipal wastewater treatment plants. Among them, the Poltva River was the most polluted water body in Ukraine.
“CLIMATE CHARACTERISTICS OF THERMAL PERIODS IN UKRAINE UNTIL THE END OF THE 21ST CENTURY. PART I: WARM PERIOD
The first article in a series of analyses on changes in thermal periods in Ukraine until the end of the 21st century is presented here. It focuses on analyzing the characteristics of the warm period, defined by a persistent transition of the average daily temperature above 0°C, separating it from the winter period. With the improvement in the spatial resolution of regional climate models (RCMs) and the updating of scenarios, there is a need to refine the characteristics of the warm period, crucial especially for agriculture and forestry. Based on data from the E-Obs database, the start dates, end dates, and duration of the warm period in Ukraine during the standard climatic period of 1961-1990 were analyzed, along with changes in these characteristics further in 1991-2010. An assessment of changes in values for future periods 2021-2040, 2041-2060, and 2081-2100 was also conducted using scenarios of representative concentration pathways (RCP 4.5 and RCP 8.5) with an ensemble of 34 RCMs from the Euro-CORDEX project with a spatial grid resolution of approximately 12×12 km. It's worth noting that previous studies by other authors have already assessed changes in the characteristics of the warm period, but using previous A1B scenarios and a much smaller number of RCMs characterized by a coarser grid of 25×25 km. According to updated climate scenarios, the duration of the warm season in the 21st century will increase across the entire territory of Ukraine, with more pronounced changes expected in the north and east. Under RCP 4.5 and RCP 8.5 scenarios, an increase in the duration of the warm period is projected in 2021-2040 relative to 1991-2010: from 7-14 days in the south to 20-23 days in the north and east of Ukraine. In the period 2041-2060, under RCP 4.5, changes will range from 7 days in the south, Transcarpathia, and the Carpathians to 20-25 days in the northeast, while under RCP 8.5, changes will range from 7-14 to 30-35 days, respectively. By the end of the century, these changes will continue, and in Crimea, there is a high likelihood that temperatures will not drop below 0°C, meaning there will be no winter season. Analysis of other thermal periods will be presented in subsequent parts of the study.
“DETERMINATION OF FLOW CHARACTERISTICS OF THE LOWER DNIPRO TAKING INTO ACCOUNT THE EXPLOSION OF KAHOVKA HPP
The full-scale invasion by the russian federation has significantly impacted the quantity and quality of water in the rivers located within the conflict zone. The explosion at the Kakhovka HPP was accompanied by the most catastrophic consequences for hydrological systems. Due to ongoing active military operations in the region of the disaster, direct measurements of water flow there are impossible. Therefore, in this study, the average year discharge of the Dnipro River for the year 2023 was calculated using computational methods. Therefore, the paper separately examined the flow of the Dnipro River for flow without Kakhovka HPP Explosion; and the actual flow in 2023. The lag time of the flow in the section between the Dnipro HPP and the Kakhovka HPP was determined through joint daily observations of water discharge in 1952 at the Dnipro HPP and Beryslav stations. Changes in the inside-year distribution of runoff were determined by comparing the actual average monthly water discharges of the Dnipro HPP with the normalized monthly discharge values of the Kakhovka HPP for the year 2023. An automated method for decoding satellite images was also used in the study to create a map showing the main stages of the desiccation of the former Kakhovka reservoir bed. Using automated satellite image interpretation, we created a map showing the main stages of dewatering of the bed of the former Kakhovka Reservoir. The difference between our calculated real flow in 2023 and the flow brought to conditions without dam blowing is water, that the Kakhovka Reservoir failed to retain could have been used for industrial and agricultural production, water supply and sewage, the normal functioning of nature reserves, tourism, water transport, and much more. All of these losses are very difficult to assess, but they definitely need to be recorded.
“SPREADING OF THE EXTREME WATER DISCHARGE FROM THE DNIPRO-BUH ESTUARY INTO THE BLACK SEA IN JUNE 2023 BY SATELLITE OBSERVATIONS DATA
A series of satellite images of the Northwestern part of the Black Sea, recorded by the MODIS and VIIRS scanners in the visible range of the spectrum from June 4 to July 1, 2023, were analyzed. Data from operational observations of the river water level and wind and seawater salinity on the Northwestern coast of the Black Sea were also used. A description of the Dnipro water anomalous distribution of in the sea after the Russian occupiers blew up the Kakhovka reservoir’s dam was obtained. Three time intervals and corresponding dynamic modes of the riverine water spreading are allocated. Quantitative indicators of the riverine water dynamics in the sea at the first stage of its expansion are calculated based on the assessment of the average water discharge for 3 days after the dam explosion. It was concluded that the abnormal discharges of the Dnipro (20.5 thousand m3/s) produce an unusual mode of the riverine water dynamics in the sea, namely, the supercritical flow from the Kinburn Strait and the formation of a buoyant plume that interacts with the bottom at a depth of no more than 6 m. According to satellite observations, the plume of turbid riverine waters moved on the shelf at a speed of more than 50 cm/s and quickly reached the Odesa Bay, forming an anticyclonic eddy structure, which later increased to more than 40 km in diameter. As a first approximation, it is accepted that after the dam explosion, about 700 tons of dissolved inorganic phosphorus and more than 1,000 tons of dissolved inorganic nitrogen entered the Black Sea. Such an unusually large amount of nutrients could obviously cause the explosive reproduction (blooming) of phytoplankton. At the qualitative level, the negative environmental consequences for the marine environment of the abnormal input of pollutants and nutrients are outlined.
“MODERN WATER CONFLICTS AND CONFRONTATIONS (HYDROGEOLOGICAL ASPECT)
The article discusses ambiguous, controversial decisions and cases of handling water resources in Ukraine and on the border territory of neighboring states. These are situations in which the water environment (water bodies) becomes an obstacle, a victim, a resource, a means of pressure, and sometimes a weapon for various participants. In wartime, water resources are used by aggressors as a weapon, including as a means of putting pressure on the population by depriving them of the necessary means of subsistence. It is shown that in democratic states, in the presence of corruption in the field of water resources management, any solutions are possible, if the propaganda company is directed accordingly. The article highlights six categories of narratives that distort the real situation and are designed to impose on society a certain decision regarding the treatment of a water body that is beneficial to one of the parties to the conflict or the beneficiary. Examples of these categories from the events of recent decades are given: the E40 waterway, the Khotyslavskyi quarry, the Kakhovs’kyi reservoir, water supply of Crimea, which is still occupied by russia, etc. Hydrogeological aspects are mostly discussed. From a comparison of a number of contradictory factors for and against the restoration of the Kakhovs’kyi reservoir, restoration is more appropriate. In the absence of a reservoir, the safe operation of Zaporizhzhya NPP even at 50% of maximum capacity becomes problematic. It is emphasized that in disputed situations, balanced decisions should be made based on the expert assessments of at least three parties: two participants in the dispute and an independent party, with the limitation of biased non-professional assessments in favor of one of the parties and the exposure of falsifications. For this, it is necessary to train specialists capable of objectively evaluating such controversial situations, and society should be educated on the priorities of 'environmentalism', rational use of resources and far-sighted benefits for the country.
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ESTIMATION OF THE INTERNAL WATER EXCHANGE VOLUME OF THE KYIV RESERVOIR USING 90SR EMISSION DATA
“ESTIMATION OF THE INTERNAL WATER EXCHANGE VOLUME OF THE KYIV RESERVOIR USING 90SR EMISSION DATA
Given that the hydrodynamics of internal and external water exchange in reservoirs creates fundamentally different living conditions for hydrobionts and significantly affects water quality, the task of separating the volumes of internal and external water exchange arises. The aim of the study is to obtain estimates of the magnitude and variability of internal and external water exchange in the Kyiv reservoir depending on the reservoir level. The research method is full-scale modeling, which consists in observing the dispersion in space of a certain passive conservative admixture (tracer) artificially introduced into the flow. As a tracer, we propose 90Sr, which by its properties almost meets the requirements for a tracer substance. The data of hydrological and toxicological monitoring in 1990-1991, 1993-1994 and 1998-1999 were used. Based on the data on 90Sr inputs to the upper reaches of the Kyiv Reservoir in 1991, 1994, and 1999, which had the character of sharp spikes, and the data on 90Sr concentrations at the outlet of the Kyiv Reservoir, the values of transport time and volumes corresponding to the time of contamination transport to the outlet of the reservoir were established. Guided by the transportation time and data on water consumption in the reservoir, calculated by the balance model, the values of the volumes of internal and external water exchange, as well as the parts that these volumes makeup of the total volume of the reservoir, were obtained. An interpolation of the dependence of the internal water exchange volume on the level of the Kyiv reservoir was constructed. The results obtained are in good agreement with some results obtained with the hydrodynamic mathematical model using the full-flow method by another group of researchers. The dependence of the volumes of internal and external water exchange of reservoirs on the reservoir level can be used to determine the time of pollution transportation along the reservoir, for environmental assessments and forecasts related to the study of water quality conditions.
