- No. 2(6) 2024
«Meteorology. Hydrology. Environmental monitoring»
“TERRESTRIAL WATER STORAGE CHANGES IN THE BUG RIVER TRANSBOUNDARY CATCHMENT OBSERVED BY GRACE AND WATER BALANCE ANALYSIS
Central and Southern Europe is undergoing a drying trend driven by increased evapotranspiration and rising air temperatures, even though precipitation levels remain stable. In the Bug River Basin, GRACE observations indicate that total water storage (TWS) declined at a rate of 8.8 ± 5.2 mm/year between 2012 and 2023. To validate this trend, we analysed spatial and temporal discrepancies between TWS-GRACE and water budget-based estimates (TWS-WB). Using ensemble data assimilation techniques, we integrated hydrometeorological data with TWS-GRACE. Regression models developed for TWS simulation were employed to adjust TWS-GRACE estimates. The results demonstrate that TWS fusion effectively mitigates uncertainties in TWS-GRACE caused by its low spatial and temporal resolution. Correlation analysis between TWS-fusion and TWS-GRACE identified errors in GRACE solutions and commonly used autoregressive methods for filling data gaps. Our findings show that model developed in this study significantly improved alignment between TWS-GRACE and TWS-WB, reducing RMSE from 34.7 to 14.9 mm/month. The proposed data fusion approach based on combining GRACE observations with precipitation, evapotranspiration, and runoff data, offers a viable alternative for extending TWS-GRACE time series beyond the GRACE observational period. Additionally, our research provides valuable insights for downscaling GRACE data and addressing challenges in spatial and temporal interpolation, which remain critical in water resource studies.
“REGARDING THE DATA INCONSISTENCY FROM DIFFERENT DATA SOURCES ON EMISSIONS AND GROUND-LEVEL POLLUTANTS’ CONCENTRATIONS IN THE ATMOSPHERIC AIR OVER UKRAINE
The development of action plans and strategies to reduce atmospheric air pollution requires the use of emissions and concentration data over extended periods. At such scales, the role of uncertainties increases, potentially leading to the development of ineffective measures. This article presents a study of the consistency of data from various sources, including official emissions inventories, modeled emissions data from the Copernicus Atmosphere Monitoring Service (CAMS), pollutant concentration data measured at stationary monitoring stations of hydrometeorological organizations, and ground-level content data from CAMS reanalysis for carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide (SO2). The research revealed significant inconsistencies among different datasets, often reflecting entirely different interannual variability and trends. While emissions predominantly show a declining trend, concentrations in most cities continue to rise based on observational data and often show no significant changes according to reanalysis data. Notably, agreement between emissions data from different sources was found in only 12 cases across citypollutant pairs. Consistency in pollutant concentration data was identified in only 3 cities for CO and 4 cities for SO2. The differences in emission volumes, even where high correlations exist, can vary by an order of magnitude for certain cities. The article provides a list of cities for each of the studied pollutants where consistency between different data sources is observed, identifying cases where the data can be complementary or interchangeable. The study emphasized that this inconsistency has negative implications for the ability to assess interannual changes, the quality of modeling and data interchangeability, the verification of evaluation results regarding the effectiveness of air quality management measures, and a wide range of other consequences.
“CLIMATE CHARACTERISTICS OF THERMAL PERIODS IN UKRAINE UNTIL THE END OF THE 21ST CENTURY. PART II: GROWING SEASON
The article presents the results of the study of thermal periods in Ukraine, namely its second part, which concerns the duration and dates of the beginning and end of the growing season, which is determined by the persistent transition of the average daily air temperature through the value of 5 °C. Climatic characteristics of the growing season determine the beginning and end of agricultural work, as well as a number of other activities that are carried out, for example, in forestry and other farms. The methods for determining climatic characteristics in this study were similar to those used in the first part, where changes in the warm period were analyzed (Krakowska et al., 2023, http://doi.org/10.15407/Meteorology2023.04.035). The values of the climatic characteristics of the growing season for the climatological norm 1961-1990 and the base period 1991-2010 were calculated using data from the European E-OBS database, and projections of changes relative to the base and values in the future three periods (2021-2040, 2041-2060 and 2081-2100) were calculated using daily data from 34 regional climate models (RCMs) of the international initiative for Europe Euro CORDEX under the RCP 4.5 and RCP 8.5 scenarios. The calculations used the eca_gsl function of the CDO (Climate Data Operator) software package to determine the dates of the steady temperature transition through 5°С. To correct the differences in the masks in E-OBS and the RCM ensemble due to the difference in the number of grid points mainly on the coastal line, the geographic information system QGIS 3.28 were used, with the help of which mapping was also carried out for visualization and analysis of the results with subsequent presentation in the form of maps in an electronic atlas using JavaScript-Leaflet library. The growing season length will increase throughout the country until the end of the century. These changes are expected to be more uniform than changes in the duration of the warm period. The duration of the growing season, which at the beginning of the 21st century was characteristic only for the southern coast of the Black Sea and the Crimean Peninsula, at the end of the century, under the implementation of the high-concentration scenario RCP 8.5, may also be characteristic of the far northeast of the country and the Ukrainian Carpathians. It is obvious that this will significantly change and will require rapid adaptation of ecosystems and changes in forestry and agro-industrial practices. The presented results can be used in the development of sectoral, national, regional and municipal strategies for adaptation to climate change.
“PROCESS AUTOMATION OF THE LONG-TERM FORECASTING OF ICE BREAK-UP AND ICE DISAPPEARANCE DATES AT THE DNIPRO RESERVOIRS
The article is devoted to the creation of an automated system "Ice-Spring" for long-term forecasting of dates of ice break-up and ice disappearance at the Dnipro Cascade reservoirs by writing a computer program for its further use in the operative work of the Ukrainian Hydrometeorological Center of the State Emergency Service of Ukraine (UkrHMC). To automate the forecasting process, the "Ice-Spring" system software was created, which is written in the C# and C++ programming languages in the Visual Studio 2022 Community Edition environment in the view of Windows forms and console applications. The "Ice-Spring" system allows for long-term forecasting of the dates of ice break-up (February 20) and ice disappearance (March 5) at the Dnipro Cascade reservoirs at 36 water gauges each year. Forecasting is carried out using 12 forecast dependencies based on regression relationships between dates on indicator water gauges and teleconnection indicators. In this case, the mean monthly values of 11 teleconnection indicators are used, which affect the processes of ice break-up and ice disappearance at the Dnipro Cascade reservoirs, which are determined by the National Weather Service (NWS) of the National Oceanic & Atmospheric Administration USA (NOAA). Forecasting on other water gauges is carried out using 60 regression dependencies between the dates at these gauges and the dates at the indicator water gauges. The created software for the automated long-term forecasting system "Ice-Spring" has successfully passed testing and has shown its performance for independent data for 2021. At the same time, carried out evaluation of forecasting efficiency has shown acceptable results, since of 12 forecasts, only 2 forecasts did not come true. The "Ice-Spring" system was transferred to the UkrHMC for testing and operative use.
“FEATURES OF THE HYDROCHEMICAL REGIME OF ANTHROPOGENICALLY ALTERED SURFACE WATER BODIES
Features of the hydrochemical regime of water bodies located within the urbanized area are considered in the article. It has been established that in winter and spring, water salinity and the content of main ions undergo the greatest changes in water bodies that receive stormwater with chemical deicing chemicals. This leads to an increase in the water salinity in general and the concentration of chlorides, sulfates, sodium and magnesium ions in particular. An increase in the concentration of inorganic nitrogen, phosphorus, organic matter and metals compounds is observed in areas of localized water pollution. Water bodies subject to significant anthropogenic impact are dominated by the inorganic form of nitrogen and phosphorus, which reaches more than 50% of their total content. Anthropogenically altered water bodies are characterized by an increase in the concentration of dissolved organic matter due to an increase in the share of carbohydrates and other unidentified groups of organic compounds, while the share of humic substances decreases. A noticeable increase in the share of carbohydrates usually occurs in summer and autumn, when the water is blooming and phytoplankton and higher aquatic plants are dying off. Anthropogenic pollution of water bodies causes an increase in the share of the labile fraction of metals, which is potentially bioavailable and toxic to aquatic life. This fraction exceeds 50% of their concentration in the dissolved state. An increase in water salinity, the content of biogenic and organic substances, and the labile fraction of metals is also observed in the bottom horizon of water bodies during direct and reverse temperature stratification due to their inflow from bottom sediments. This is primarily due to dissolved oxygen deficiency, a decrease in Eh-potential values, and an increase in water temperature. Secondary water pollution by nutrients should be considered as an important internal source of increased eutrophication of water bodies. As a result, the aquatic environment becomes unsuitable for the life of many oxyphilic aquatic organisms. As the climate warms, these processes will intensify. Therefore, it is important to develop a number of measures to prevent or minimize both external and internal nutrient flows to surface water bodies.
“MANIFESTATIONS OF THE INTERACTION OF RIVERINE AND MARINE WATERS IN THE STATISTICAL STRUCTURE OF SALINITY BY THE OBSERVATIONS DATA AT COASTAL STATIONS OF UKRAINE
Time series of water salinity observations from 1997 to 2010 at marine hydrometeorological stations on the northern coast of the Northwestern Black Sea from the mouth of the Dnipro-Buh Estuary (Kinburn Strait) to the Gulf of Odesa are analyzed. Empirical probability distribution functions of salinity were constructed for the Ochakiv, Pivdenny and Odesa-port stations for all months and year as a whole. Using the mixture analysis method, one-dimensional clustering of empirical salinity histograms is performed under the assumption that they consist of several normal distribution functions, each of which represents a separate water mass and is characterized by its own indicators - the average value, standard deviation and share (proportion) in the general distribution (mixture). To search for optimal solutions, the maximum likelihood method and the Akaike information criterion were applied. Experimentally, taking into account the peculiarities of the water dynamics in the northern part of the Northwestern Black Sea shelf, it was established that salinity histograms can be approximated by a set of 2-3 Gaussian functions. These functions, as a rule, correspond to waters of river origin, marine origin and intermediate waters as a result of the interaction of the first two. The approximation parameters (mean values, standard deviation and proportion in the mixture) vary in space depending on the distance to the source of desalination or salinization, as well as in time in accordance with the seasonal variability of the processes of supply and interaction of water masses on the North-Western Black Sea shelf. Numerical indicators of the components that make up the water mixture near the northern shores of the North-Western part of the Black Sea have been obtained. They can be used for probabilistic modeling (forecasting) of water salinity at different points both for separate months and for the whole year, for example, by means the method Monte Carlo.
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OPTIMIZATION METHODS FOR THE CREATION OF WEB-BASED ATLAS "CLIMATE AND WATER RESOURCES OF UKRAINE"
“OPTIMIZATION METHODS FOR THE CREATION OF WEB-BASED ATLAS "CLIMATE AND WATER RESOURCES OF UKRAINE"
The purpose of this study is to summarize methods for optimizing the process of creating a web-based atlas “Climate and Water Resources of Ukraine”. The methods of optimizing the creation of the atlas web shell, the maps themselves, the drafting of the atlas and its implementation are considered. The literature review considers the peculiarities of creating fundamental cartographic works, the time spent on it, and shows the importance of using methods to optimize the production of cartographic products. The experience of atlas mapping of specialists involved in the creation of the atlas is also considered. The essence of serial mapping using an automatic mapping system, large-node assembly (web-based atlas shell), pyramidal project development algorithm, reduction of the number of production processes, method of map unification, grouping of the same or similar tasks, use of a “shortened technical project file”, automation of production processes, step-by-step progress with a predefined result are described in detail. As a result of using these methods, the time spent on the development of the atlas was reduced from 7 thousand working hours to 1.5 thousand. The development of the atlas was completed in 2023 and published here: https://maps.uhmi.org.ua. It is concluded that these optimization methods constitute a supercompetence responsible for the quality and productivity of labor. The atlas contains more than 5,000 maps, most of which were made using the developed methodology. These maps show the average, maximum, and minimum air temperature for the month, precipitation, climate temperature norm, climate change forecast, cold waves, heat waves and sudden changes in air temperature, and many other indicators.
