Regionalization of Ukraine based on the influence of extreme values of maximum air temperature during warm and cold periods of the year

Savchuk, S. V.; Yuvchenko, N. N.; Тимофеев, В. Е.

doi:10.31481/uhmj.22.2018.05

Cited by 4 publications

(2 citation statements)

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“…In Ukraine, air temperature showed a large increase from 2000 to 2020, especially in the warm period of the year when extreme temperatures became more frequent in the country, as well as globally (Perkins‐Kirkpatrick & Lewis, 2020; Savchuk et al, 2018; Semenova, 2022). The observed changes in the temperature regime are confirmed by changes in atmospheric circulation in Europe, which led to an increase in the duration of sunshine (Marsz et al, 2022) and change in the characteristics of the radiation balance, including most regions of Ukraine (Rybchenko et al, 2022).…”

Section: Discussionmentioning

confidence: 99%

Long‐term variability and trends of meteorological droughts in Ukraine

Semenova,

Vicente‐Serrano

2024

Intl Journal of Climatology

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The purpose of this research is to identify changes in the spatiotemporal distribution and severity of meteorological droughts in Ukraine between 1946 and 2020. In order to determine the role of precipitation and atmospheric evaporative demand on drought severity, two drought indices were applied for comparative analysis: the standardized precipitation index (SPI) and the standardized evaporation precipitation index (SPEI). Both indices were calculated on 3‐ and 12‐month timescales. The gridded dataset of monthly air temperature and atmospheric precipitation for Ukraine with high spatial resolution (0.1° × 0.1°), developed in the Ukrainian Hydrometeorological Institute, was used. Results of time series analysis of drought indices showed at least 20 episodes, in which more than 25% of the territory of Ukraine was affected by drought of varying intensity. Trends show an increase in drought severity determined mostly by a strong observed increase in the atmospheric evaporative demand. Tendencies towards an increase in the duration and intensity of droughts were observed mainly in the southwestern, central and northern regions of Ukraine. The main cause of the increase was droughts in spring and summer. The temporal analysis of the spatial distribution of areas affected by drought during the identified main drought episodes showed different patterns in drought propagation across the territory of Ukraine.

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Section: Discussionmentioning

confidence: 99%

Long‐term variability and trends of meteorological droughts in Ukraine

Semenova,

Vicente‐Serrano

2024

Intl Journal of Climatology

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“…В умовах сучасної зміни клімату, що супроводжується зростанням багаторічного ходу глобальних [6] та регіональних температур повітря [7], тенденцій у зв'язку з цим до підвищення абсолютної вологості та, своєю чергою, зниження відносної вологості, що впливає на величину випаровування з поверхні водозборів і водойм [8], перерозподілом опадів у часі та просторі [9], зміщенням сезонів у році [10], [11] спостерігаються й зміни сучасної та, навіть, майбутньої водності річок [12]- [21], розподіл стоку річок протягом року [15,22].…”

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Probabilistic-forecasting method for determination of low flow discharge of Pivdennyi Buh, Black Sea area, and Lower Dnieper rivers

Shakirzanova

Ovcharuk

Dokus

et al. 2022

Visnyk of V.N. Karazin Kharkiv National University, Series Geology. Geography. Ecology

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The aim of the study is to substantiate the probabilistic-forecasting method for forecasting the low flow discharge and its implementation for the Pivdennyi Buh, Black Sea area and Lower Dnieper rivers, taking into account climatic patterns of precipitation distribution and establishing probabilistic characteristics of low flow discharge in multi-year period. The study area is in a zone of significant risk due to the shortage of water resources, the formation of extremely low runoff in the dry flow period, which requires its definition and forecasting. The methodological basis of forecasts is to solve the equation in determining the components of the low flow of rivers by constructing regional dependences for forecasting the average decade summer-autumn low flow from previous water discharge (in runoff modules), establishing their probabilities water discharge for a number of intakes. Results. The paper substantiates the probabilistic-forecasting method for forecasting low flow discharge (in summer, autumn and winter periods) based on the construction of regional dependences of average decadal runoff modules on previous water discharge for groups of basins of studied rivers taking into account climatic dependences of precipitation distribution in the territory and the establishment of probabilistic characteristics of the low flow water discharge in a multi-year period. The methodology of territorial short-term forecasts of average decade water discharge of low flow of summer, autumn and winter river runoff is assessed as satisfactory with a margin of error of 70 % to 97 %, with a number of members of more than 500 points. To determine the cumulative probability of the forecast values of the average decade water discharge of the summer, autumn and winter dry weather flow, the empirical distribution of the average monthly water discharge in the limited seasons, which are generalized in the basins of the studied rivers of Ukraine, is established. Scientific novelty. For the first time for the zone of insufficient natural water content of rivers the method of territorial forecasts of low flow discharge, determination of their probability of occurrence in a multi-year period and cartographic representation of prognostic values have been developed and practically implemented. The practical importance is the use of forecast modules maps of low flow for spatial monitoring and assessment of low water levels on rivers in the whole region, including ungauged rivers, and their probabilistic characteristics – to assess the possible occurrence of low runoff, even when it reaches values close to the environmental runoff, which are critical for the functioning of the river ecosystem.

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Correlation Communication Between Meteorological Parameters at Extreme Values of Maximum Air Temperatures

Savchuk

Тимофеев

Shcheglov

et al. 2020

Hydrology, Hydrochemistry and Hydroecology

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The object of the study is the maximum daily air temperature during the months of the year over 1991-2016 by the data of 186 meteorological stations of Ukraine. Extreme values of the maximum daily temperature equal to or exceeded their 95th (Tmax95p and above, ºС) percentile were taken as extreme. The article sets the dates (137 cases) of extreme values of maximum air temperature on more than 60 % of the territory. For these dates, 13 meteorological parameters were selected: average, minimum, and maximum air temperatures; average, minimum and maximum relative humidity; station and sea-level pressure; average, maximum (from 8 synoptic hours) wind speed; rainfall; height of snow cover. The purpose of this work is to determine the correlation coefficient (K), in particular, statistically significant (K≤-0.6, K≥0.6), on these dates between selected meteorological parameters at 186 meteorological stations of Ukraine for 1991-2013. The density of the cases of statistically significant dependence between the meteorological parameters in extremely warm days in separate seasons is determined. In extremely warm days, meteorological parameters and areas with statistically significant correlations at K≤-0.6 were detected: T and F (focally in southern and some western regions with significant density) − in winter; T and F (with the highest density ubiquitous or almost ubiquitous), P and V (in a large number of regions, usually west or right-bank, but with less frequency) − in the transition seasons, and in the autumn between − T and F (in the south with smaller density) and P and F (in some areas of the north, northwest, west, lower east). In all seasons, such a correlation between other meteorological parameters had a focal distribution, usually with a smaller density. In these days, a focal distribution with a small frequency of dependencies at K≥0.6 was found between the meteorological parameters detected (F and V in transition seasons, T and F in winter), except for similar ones. However, such dependence is observed between T and V in some regions in winter and autumn and in some areas of south, southeast, east with a smaller density. The study of the maximum daily temperature is relevant, because from the level of natural hydrometeorological phenomena it is accompanied by dangerous phenomena, negatively affecting the weather dependent industries.

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Regionalization of Ukraine based on the influence of extreme values of maximum air temperature during warm and cold periods of the year

Cited by 4 publications

References 0 publications

Long‐term variability and trends of meteorological droughts in Ukraine

Long‐term variability and trends of meteorological droughts in Ukraine

Probabilistic-forecasting method for determination of low flow discharge of Pivdennyi Buh, Black Sea area, and Lower Dnieper rivers

Correlation Communication Between Meteorological Parameters at Extreme Values of Maximum Air Temperatures

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