Wyniki wyszukiwania - Biblioteka Nauki

1

Trends In Groundwater Level Changes in Small Forest Catchments of Wielkopolska

100%

Stasik R. , Korytowski M. , Liberacki D.

Journal of Ecological Engineering

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2016

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tom Vol. 17, nr 4

99--106

EN

Trends in groundwater level changes in small forest catchments located in Wielkopolska region were analysed on the basis on data collected for many years of groundwater levels observations. The observations were carried out from 2000 to 2010 hydrological year in Marianka Siemiańska and Laski forest district as well as in Puszcza Zielonka. The groundwater levels were measured in soil profiles located in different forest habitats: fresh, moist and swamp forest. Changes in groundwater level determined using the Mann-Kendall test were found to differ significantly between the catchment studied. Statistically insignificant decrease in groundwater levels was observed at all forest sites in the catchment area in Marianka Siemiańska forest district. In the catchment area of the Hutka watercourse the groundwater level showed a statistically significant decreasing tendency in Puszcza Zielonka in swamp and fresh mixed coniferous forest. It may indicate a decrease in water resources and implies the need of groundwater level monitoring. A statistically insignificant increase in groundwater level was observed in the wells in moist mixed broadleaved forest in the area of pond catchment in Laski forest district, this trend was interpreted as a result of the clearcutting made in this area.

2

Trend analysis of changes in soil moisture from the different depths in the Martew Forestry

100%

Krysztofiak-Kaniewska A. , Miler A. T. , Urbaniak M. , Ziemblińska K. , Wróbel M.

Infrastruktura i Ekologia Terenów Wiejskich

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2016

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tom nr IV/1

1157--1167

EN

The paper presents trends in average annual soil moisture in the area covered by the sixty-year old pine stand. The area of analysis is located in the Tuczno Forest District, the Martew Forestry, in the north-western part of Poland. The calculations were based on the measurements of soil moisture at seven different depths below the ground level. A set of probes was installed for measuring the moisture using TDR method in order to calculate retention changes in the unsaturated zone. Humidity measurements used in this work were carried out at daily intervals throughout the year 2014. Designated trends were analysed using the non-parametric Mann – Kendall test, which is used for detecting trend of hydrological and meteorological parameters. Negative values of the Mann-Kendall statistics point to a declining trend for most – six out of the seven, analysed levels of measurement. The tendency toward dryness was not confirmed by the data set of precipitations. Although precipitations are considered to be the main driver of variations in soil moisture their impact severity seems to be controlled by other characteristics of the catchment area and components of the water balance, such as evapotranspiration.

3

Trends in monthly, seasonal, and annual fluctuations in flood peaks for the upper Dniester River

88%

Melnyk S. , Loboda N.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2020

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tom Vol. 8, Iss. 2

28--36

EN

The importance of the Dniester River in the socio-economic life of Moldova and Ukraine necessitates research into the main trends in the river’s runoff characteristics and dynamics, especially now, when climate change is significantly altering the water regime of rivers. This paper presents a solution for the problems of identifying the main trends in daily maximum river discharge by seasons and months for various calculation intervals. Two calculation intervals (1981-1998; 1999-2015) with different climatic conditions are considered. Each interval corresponds to one complete cycle of river water discharge. Climatic conditions as a result of global warming are changing differently in the mountains and on the plain, therefore, the identification of trends was performed separately for the alpine and lowland parts of the Dniester River annual runoff formation zone. The search for statistically significant trends was carried out by means of the MannKendall test. The analysis of the frequency of maximum discharges (peak over threshold; POT3) was performed for selected rivers in the studied area. The earlier period (1981-1998) showed statistically significant positive trends for both alpine and lowland rivers of the Upper Dniester. The later period (1999-2015) differed, exhibiting exclusively negative significant trends in daily peaks both by months and by seasons. This result indicates a persistent tendency toward decreasing maximum water runoff for all rivers of the Upper Dniester catchment. There were no statistically significant trends in the frequency of floods.

4

Analyzing trends in reference evapotranspiration in Northwest part of Iran

88%

Azizzadeh M. , Javan K.

Journal of Ecological Engineering

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2015

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tom Vol. 16, nr 2

1--12

EN

Evapotranspiration is one of the most important components of the hydrological cycle. It is essential in all of hydro climatological studies, irrigation and drainage calculations, water balance, and crop water requirements. The aim of this study is to investigate temporal trends of reference evapotranspiration (ETo) in the Northwest part of Iran. For this purpose, the meteorological data from 20 synoptic stations over a 22-year time period (1986–2007) were used. After the calculation of ETo using the Penman-Monteith FAO-56 method, the non-parametric Mann-Kendall test was used to investigate the temporal trends on monthly, seasonal and annual scales. The Sen’s estimator method was used and to calculate the slope of the trend line. The results indicated that the ETo trend was increasing (positive) in various months, except for the Sarab station in December. On a monthly scale, the Maragheh station showed the highest positive slope in August, and the Bijar station showed the highest negative slope in May. 43.34% of the stations showed a significant trend, and 56.66% did not show a significant trend. In seasonal and annual time periods there was not a significant decreasing trend in any of the stations. The analysis of the results shows that in the spring 20%, in the summer 55%, in the fall 70%, in the winter 75%, and on an annual scale 60% of the stations under study showed an increasing trend. For modeling these changes, the spatial distribution of ETo trends (on monthly, seasonal, and annual scales) were mapped in ArcGIS. Final models determine that most stations in this study show an increasing trend on monthly, seasonal and annual scales.

5

A probabilistic model for flood forecasting based on hydrological data in the state of Maranhão, Brazil

88%

Borges L. d. S. , Nobre J. C. d. A. , Sousa de D. L. P. , Andrade L. C. F.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2024

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tom Vol. 12, Iss. 1

50--64

EN

Investigating critical precipitation phenomena is essential for predicting flood events. In this study, data from 8 hydrological stations in the state of Maranhão in northeastern Brazil were analyzed. The first step involved collecting valid data from the time series of 4 municipalities (Açailândia, Arame, Buriticupu, and Santa Luzia), which were affected by floods due to heavy rainfall in the region. The aim was to use a probabilistic model to predict the occurrence of new floods based on rainfall and river discharge patterns. Atypical precipitation points were identified in boxplots, confirming the correlation between heavy rainfall and floods in 2023. The exponential equations-based model estimated the river discharge during the floods. The Flow Duration Curves (FDC) indicated the probability of events of equal or greater magnitude occurring as follows: Açailândia (10%), Arame (15%), Buriticupu (32%), and Santa Luzia (<5%). Finally, significant trends in the monthly precipitation series were investigated using the Mann-Kendall test.

6

On the long-term variability of temperature trends and changes in surface air temperature in Kolkata Weather Observatory, West Bengal, India

88%

Khan A. , Chatterjee S. , Bisai D.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2015

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tom Vol. 3, Iss. 2

9--16

EN

The impact of climate change on annual air temperature has received a great deal of attention from climatologists worldwide. Many studies have been conducted to illustrate that changes in temperature are becoming evident on a global scale. Air temperature, one of the most important components of climate parameters, has been widely measured as a starting point towards the apprehension of climate change and variability. The main objective of this study is to analyse the temporal variability of mean monthly temperature for the period of 1941 to 2010 (70 years). To detect the magnitude of trend in mean monthly temperature time series, we have used non-parametric test methods such as The Mann-Kendall test, often combined with the Theil-Sen’s robust estimate of linear trend. Whatever test is used, the user should understand the underlying assumptions of both the technique used to generate the estimates of a trend and the statistical methods used for testing. The results of this analysis reveal that four months – January, February, March and December – indicate a decreasing trend in average temperature, while the remaining eight months have an increasing trend. The magnitude of Mann-Kendall trend statistic Zc for this declining temperature and the magnitude of slope for the months of January, February and December are confirmed at the high significance levels of α = 0.001, 0.01 and 0.1 respectively. Though, the overall trend is positive for monthly as well as seasonally efficient time series.

7

Impact of a small storage reservoir on the hydro-chemical regime of a flysch stream : A case study for the Korzeń stream (Poland)

75%

Fudała W. , Bogdał A. , Kowalik T.

Journal of Water and Land Development

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2023

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tom no. 59

13--24

EN

The paper presents in form of a case study the results of 10-year long hydro-chemical studies on the Korzeń stream on which the “Skrzyszów” small storage reservoir was built. Studies aimed at evaluating the impact of the reservoir on the surface water quality in a Flysch stream. The basis for the analysis was results of 21 hydro-chemical water quality parameters, from the following groups of indicators: physical and acidity, oxygen and organic pollution, biogenic, salinity, metals. Indicators were determined in one-month intervals in two periods: 2005-2009 (before the reservoir was built) and 2015–2019 (after the reservoir was built). Obtained results were subjected to a statistical analysis. The trend analysis of changes was performed using the Mann-Kendall test or the seasonal Kendall test; significance of differences between indicator values from two periods was evaluated using the nonparametric Mann-Whitney U test. Results of analysis showed significant change trends of water quality parameters, in case of total iron concentration the trend was downward in both periods. Statistically significant differences between the values of definite majority of indicators were found in two analysed periods, indicating both favourable and unfavourable impact of the reservoir on water quality in the stream. Construction of the storage reservoir resulted in a significant change of physical and chemical indicators of water flowing in the stream. Random variation dynamics as well as tendencies and trends of changes over time have changed. In addition to modifying the stream hydro-chemical regime, the reservoir also affected the social and natural conditions.

8

Statistical assessment of rainfall variability and trends in northeastern Algeria

75%

Merniz N. , Tahar A. , Benmehaia A. M.

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9

Assessment of the impact of climate change on the freshwater availability of Kaduna River basin, Nigeria

75%

Okafor G. C. , Ogbu K. N.

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10

Analysis of distribution of precipitation duration and amounts in Legnica in the period of 1966–2015

75%

Jakubczyk T.

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nr 41

11

The Short-Term and Seasonal Trend Detection of Sediment Discharges in Turkish Rivers

75%

Burgan H. I.

Rocznik Ochrona Środowiska

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2022

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tom Tom 24

214--230

EN

Hydrometeorological variables are tested by trend methods to detect trends in river basins. Mann-Kendall and Spearman’s rho tests are widely used as traditional trend methods. Besides, some new trend tests are applied to hydrometeorological variables, such as Innovative Trend Analysis (ITA). Sediment discharge observations are more complicated than other hydrometeorological variables. In general, sediment data are observed on a monthly time scale. Therefore, there are minimal studies on sediment data, especially in Turkey. In this study, Innovative Trend Analysis (ITA), Mann-Kendall, Correlated Mann-Kendall and Seasonal Mann-Kendall trend analyses are applied to sediment discharges in Turkish river basins. According to Mann-Kendall, Correlated Mann-Kendall and Seasonal Mann-Kendall results, positive trends have detected only 8, 2 and 20 gauging stations, respectively. Then, 30 positive and 15 negative trends were detected by ITA methodology. The trend slopes calculated from ITA methodology are categorised because some positive and negative trends are weak. The applied trend methods are evaluated together, considering the climate properties of hydrological regions in Turkey. Increasing trends in sediment data are detected from the rivers in the Mediterranean region of Turkey. The results of the study would help to manage water resources as well as sustainable development in the Turkish river basins.

12

Analiza zmienności parametrów klimatycznych i hydrologicznych w dolinie rzeki Biebrzy

75%

Maksymiuk A. , Furmańczyk K. , Ignar S. , Krupa J. , Okruszko T.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2008

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tom Vol. 17, No. 3

59--68

EN

Wetlands are endangered ecosystems. The main, most observe and forecast risk for the wetlands is global climate change. The paper presents the analysis of multiyear tendencies of changes of climatic and hydrologic characteristics in the Biebrza River basin in 1966-2003 with the use of Mann-Kendall test. The analysis of climatic characteristics let to state, that climate warming is noticeable in Poland and in the Biebrza River too. In case of the analysis of hydrologic characteristics the changes are less noticeable. Nevertheless we can talk about the initial phase of lowering of maximum water levels and of maximum discharges which in decisive way influence the wetlands.

13

Water Quality Trends of the Tisa River Along its Flow Through Serbia

63%

Dundjerski J. J. , Savic R. , Grabic J. , Blagojevic B.

Rocznik Ochrona Środowiska

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2017

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tom Tom 19

17--35

EN

The problem of the paper is water quality of the water body Tisa which geographically belongs to Serbia. The scope of the analyses are water quality monitoring data of the Tisa River at tree measuring points along its flow through Serbia: Martonos, Novi Becej and Titel in period 2004-2014. The analyses encompassed conductivity, dissolved oxygen, BOD5, COD, nitrates and total phosphorus. Assessment of water quality has been conducted by the application of contemporary classifications and criteria of the Republic of Serbia. Reference conditions for achieving excellent ecological status, I class of water quality are achieved for conductivity, dissolved oxygen, along investigated section (measuring points: Martonos, Novi Becej and Titel) and BOD5 at the measuring point Martonos. Downstream at measuring points Novi Becej and Titel for BOD5 water quality belongs to class II. According to concentrations of COD, nitrates and total phosphorus water quality belongs exclusively to class II. Linear regression analyses was applied for determining trend lines of parameters, while Mann-Kendell test in most cases (14/18), i.e. 78%, has confirmed nonexistence of significant trend. Water quality during the past decade is stable. A statistically significant trend was confirmed in 4 cases: nitrates (measuring point Martonos, descending trend), BOD5 and total phosphorus (measuring point Novi Becej, descending trend), and dissolved oxygen (measuring point Titel, increasing trend). Signs of these trends speak in favor of future improvement of water quality of the Tisa River in Serbia.

PL

W artykule opisano jakość wody w rzece Tisa, która geograficznie należy do Serbii. Zakres analiz obejmuje są dane dotyczące jakości wody w rzece Tisa w punktach pomiarowych wzdłuż biegu przez Serbię: Martonos, Novi Becej i Titel w latach 2004-2014. Analizą objęto: przewodnictwo, tlen rozpuszczony, BZT5, ChZT, azotany i fosfor ogólny. Ocena jakości wody została przeprowadzona przez zastosowanie aktualnej klasyfikacji i kryteriów w Republice Serbii. Warunki parametrów odpowiadające doskonałemu stanowi ekologicznemu, I klasy jakości wody, osiągnięto dla przewodności, tlenu rozpuszczonego, wzdłuż całego badanego odcinka (punkty pomiarowe: Martonos, Novi Becej i Titel) oraz BZT5, w punkcie pomiarowym Martonos. W dolnym biegu rzeki, w punktach pomiarowych Novi Becej i Titel dla BZT5 wody należą do klasy II. Jeśli chodzi o ChZT, azotany i fosfor całkowity jakość wody należy do klasy II. W celu określenia linii trendu parametrów zastosowano analizę regresji liniowej, a test Manna-Kendalla, w większości przypadków (14/18), tj. 78%, potwierdził brak znaczącego trendu. Jakość wody w ciągu ostatnich dziesięciu lat jest stabilna. W 4 przypadkach stwierdzono statystycznie istotną tendencję: azotany (punkt pomiarowy Martonos, tendencja spadkowa), BZT5 i fosfor ogólny (punkt pomiarowy Novi Becej, tendencja spadkowa) oraz tlen rozpuszczony (punkt pomiarowy Titel, tendencja wzrostowa). Trendy mogą oznaczać poprawą jakości wody rzeki Tisa w Serbii w przyszłości.

14

Impact of climate fluctuations on the spring runoff regime with regard to rivers in Lithuania

63%

Bagdžiūnaitė-Litvinaitienė L. , Litvinaitis A.

Journal of Water and Land Development

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2015

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tom no. 25

23--30

EN

The article describes the impact of fluctuations in climatic factors on hydrological processes. The analysis of climate and hydrology covers two periods, the first up to 1996 and the second from 1981 to 2012. Study object includes 22 river basins situated on the eastern coast of the Baltic Sea: 1000 km2, up to 10 000 km2 and bigger. The study involved Mann–Kendall, Spearman's and linear regression tests. Causal relationships, as criteria that may fundamentally change the runoff regime set up by climatic factors, were established by evaluating the size of the river basin and assessing the spread of sediments, lakes, swamps and forests in the river basin. The analysis of data from the last thirty years disclosed that, with reference to the previously obtained information, floods in lakes became substantially reduced. Nevertheless, within the winter period of recent years, temperatures prevented lakes from acting as water reservoirs. The paper examined and defined the impact of sediments on variations in the runoff regime. For the period of the last thirty years, cut-off dates, i.e. flood start, crest and end, have advanced.

PL

Przedmiotem artykułu jest wpływ czynników klimatycznych na zmianę procesów hydrologicznych. Dokonano analizy klimatycznej i hydrologicznej dwóch okresów: do roku 1996 i od roku 1981 do 2012. Obiektem badań były zlewnie 22 rzek we wschodniej części wybrzeża Morza Bałtyckiego: do 1000 km2, do 10 000 km2 i większe. W badaniach stosowano testy statystyczne Manna–Kendalla, Spearmana i regresji liniowej przeznaczone do ustalenia związku przyczynowego w ocenie wielkości zlewni rzeki, osadów, jezior, bagien, zalesienia w zlewni rzeki jako kryteria, które w zasadniczy sposób mogą zmienić reżim odpływu ukształtowany przez czynniki klimatyczne. Analiza danych pochodzących z ostatnich trzydziestu lat wykazała, że według wcześniejszych danych jeziora w większym stopniu ograniczały występowanie powodzi, jednak w ostatnich latach temperatura w sezonie zimowym nie pozwala jeziorom pełnić funkcji akumulatorów wodnych. Zanalizowano i określono wpływ osadów na zmiany reżimu przepływu. Stwierdzono, że w ciągu ostatnich trzydziestu lat graniczne daty powodzi – początek, szczyt i koniec – notowane są wcześniej.

15

Maximum daily rainfall analysis at selected meteorological stations in the upper Lusatian Neisse River basin

63%

Wdowikowski M. , Kaźmierczak B. , Ledvinka O.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2016

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tom Vol. 4, Iss. 1

53--63

EN

The scope of this study was to assess the usefulness of top probability distributions to describe maximum rainfall data in the Lusatian Neisse River basin, based on eight IMWM-NRI meteorological stations. The research material was composed of 50-year precipitation series of daily totals from 1961 to 2010. Misssing measurement data were estimated using a weighted average method. Homogeneity for refilled data were investigated by precipitation double aggregation curve. Correlation between the measurement data varied from 96 to 99% and did not indicate a violation of the homogeneity of rainfall data series. Variability of recorded daily precipitation maxima were studied by linear regression and non-parametric Mann-Kendall tests. Long-term period changes at maximum rainfalls for four stations remained statistically insignificant, and for the other four were significant, although the structure of maximums was relatively similar. To describe the measured data, there were used the Fréchet, Gamma, Generalized Exponential Distribution (GED), Gumbel, Log-normal and Weibull distributions. Particular distribution parameters were estimated using the maximum likelihood method. The conformity of the analyzed theoretical distributions with measured data was inspected using the Schwarz Bayesian information criterion (BIC) and also by the relative residual mean square error (RRMSE). Among others, the Gamma, GED, and Weibull distributions fulfilled the compliance criterion for each meteorological station respectively. The BIC criterion indicated GED as the best; however differences were minor between GED on the one hand and the Gamma and Weibull distributions on the other. After conducting the RRMSE analysis it was found that, in comparison to the other distributions, GED best describes the measured maximum rainfall data.

16

Zmiany zachorowalności na nowotwory złośliwe ośrodkowego układu nerwowego w województwie wielkopolskim

63%

Pilarska A.

Rozwój Regionalny i Polityka Regionalna

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2021

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nr 57

57-68

EN

The paper analyzes the spatial and temporal change in the raw incidence rate of malignant neoplasms of the central nervous system (including the meninges), determines the nature and strength of the incidence trends, and identifies areas of unfavorable and favorable situation. An unfavorable situation in terms of raw incidence rate of the analyzed malignant neoplasms was observed in the subregion of the town of Poznań, the Kalisz subregion and the Piła poviat. In the Wielkopolska voivodship, statistically significant upward trends in incidence were recorded for “malignant neoplasm of meninges (C70)*” and “malignant neoplasm of brain (C71)*”. The only statis- tically significant downward trend in incidence occurred in the Piła subregion and concerned “malignant neoplasm of spinal cord, cranial nerves and other parts of central nervous system (C72)*”. *English names of the malignant neoplasms which are in the ICD-10 have been taken from: https:// icd.who.int/browse10/2010/en#/C69-C72 (accessed: 10.09.2021).

PL

W pracy dokonano analizy przestrzennej i czasowej zmiany współczynnika surowego zachorowalności na nowotwory złośliwe ośrodkowego układu nerwowego (z uwzględnieniem opon mózgowo-rdzeniowych), określono charakter i siłę trendów zachorowalności oraz wskazano obszary o niekorzystnej i korzystnej sytuacji. Niekorzystna sytuacja w zakresie zachorowalności surowej na analizowane nowotwory występowała w podregionie miasto Poznań, podregionie kaliskim oraz w powiecie pilskim. W województwie wielkopolskim istotne statystycznie trendy wzrostowe zachorowalności odnotowano dla „nowotworu złośliwego opon mózgowo-rdzeniowych (C70)” oraz „nowotworu złośliwego mózgu (C71)”. Jedyny istotny statystycznie trend spadkowy zachorowalności wystąpił w podregionie pilskim i dotyczył „nowotworu złośliwego rdzenia kręgowego, nerwów czaszkowych i innych części ośrodkowego układu nerwowego (C72)”.

17

Statistical assessment of rainfall variability and trends in northeastern Algeria

63%

Merniz N. , Tahar A. , Benmehaia A. M.

Journal of Water and Land Development

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2019

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tom no. 40

87--96

EN

In the present study, time series for annual, monthly rainfall and number of rainy days per year were analysed to quantify spatial variability and temporal trends for 22 rainfall stations distributed in northeastern Algeria for the period 1978– 2010. The Mann–Kendall test and the Sen’s slope estimator were applied to assess the significance and magnitude of the trend. The results showed that precipitation decreases spatially from North to South and from East to West. The application of the Mann–Kendall test (for 0.05% threshold) to the time series data showed that for annual precipitation, no station showed statistically significant trends, unlike the number of rainy days, where there was a significant negative trend in four stations (Jijel, Constantine, Oum El Bouaghi and Tébessa). For the monthly time series, significant positive trends were observed during the months of September in the coastal stations and July for the plateaus and southern Saharan Atlas stations, while significant negative trends were recorded during the months of February and March for the stations of the extreme East in the study area. These results revealed that for the period analysed, there was no significant climate change in northeastern Algeria but there is a seasonal delay having important agroecological implications.

PL

W przedstawionych badaniach analizowano serie rocznych i miesięcznych opadów oraz liczbę dni z deszczem w ciągu roku celem ustalenia przestrzennej zmienności i czasowych trendów w latach 1978–2010 dla 22 stacji pomiarowych rozmieszczonych w północnowschodniej Algierii. Wykorzystano test Manna–Kendalla i estymator Sena do oceny istotności i rozmiaru trendu. Wyniki dowodzą, że opady malały z północy na południe i ze wschodu na zachód. Zastosowanie testu Manna–Kendalla (p < 0,05) do serii danych pomiarowych nie wykazały w żadnej stacji statystycznie istotnych trendów dla rocznych opadów w przeciwieństwie do liczby dni z opadem, które cechował istotny negatywny trend w czterech stacjach pomiarowych (Jijel, Constantine, Oum El Bouaghi i Tébessa). Analiza serii miesięcznych opadów dowiodła występowania dodatniego trendu w odniesieniu do sierpnia w stacjach na wybrzeżu i w odniesieniu do lipca w stacjach na płaskowyżach i w południowym Atlasie Saharyjskim. Istotny trend ujemny uzyskano w przypadku lutego i marca w stacjach na wschodzie badanego obszaru. Wyniki dowodzą, że w analizowanym okresie nie stwierdzono istotnych zmian klimatu w północnowschodniej Algierii, z wyjątkiem sezonowych opóźnień, które wywołują ważne skutki agro-ekologiczne.

18

Analysis of spatial variation of temperature trends in the semiarid Euphrates basin using statistical approaches

63%

Katipoğlu O. M.

Acta Geophysica

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2022

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tom Vol. 70, no 4

1899--1921

EN

This study analyzes the spatial and temporal distribution of trends on monthly, seasonal, and annual mean temperatures (1967–2017) at 22 stations in the Euphrates Basin of Turkey. The recently proposed innovative trend analysis (ITA) and the nonparametric Mann–Kendall (MK) and Spearman’s rho (SR) test at 5% and 1% significance levels were applied to examine the temporal trends of temperatures. Before using the nonparametric trend analysis, the serial correlation of the temperature data was removed with the pre-whitening (PW) method. Then, MK-Z values were mapped in ArcGIS environment using the Empirical Bayesian Kriging (EBK) method to reveal the spatial variation of temperature trends. As a result, according to the ITA method, increasing temperature trends at 1% significance level dominate almost all periods. Based on the MK and SR tests, it was identified that increase trends were dominant at 1% and 5% significance levels in February, March, April, July, August, Spring, Summer, and Annual periods. According to the spatial temperature trend maps, significant increase trends occupy an important place in most of the basin in February, March, April, June, July, August, Spring, Summer, Winter, and Annual periods. The study results provide important information to water resources managers and decision-makers about the regions at significant risk in climate change in the Euphrates Basin.

19

Trend analysis of water quality parameters in the middle part of the Danube flow in Serbia

63%

Salvai A. , Grabic J. , Josimov-Dundjerski J. , Zemunac R. , Antonic N. , Savic R. , Blagojevic B.

Ecological Chemistry and Engineering. S

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2022

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tom Vol. 29, nr 1

51--63

EN

The Danube River plays significant role not only for preserving natural ecosystems. The aim of this paper is to examine the Middle Danube water quality in the part flowing through Serbia in section Bezdan - Banatska Palanka. Water quality data were examined for seven control points for period 2004-2018, for seven parameters: suspended solids (SS), dissolved oxygen (DO), electrical conductivity (EC), nitrates (NO3–-N), total phosphorus (Ptot), biochemical oxygen demand (BOD5) and chemical oxygen demand (COD). Data analyses included the application of ANOVA, linear regression analysis and Mann-Kendall trend test. The Mann-Kendall tests in most (32/49) cases, i.e. in 65 %, confirmed the non-existence of a significant trend. Significant downward trends were confirmed in 17 cases. Water quality improvement was confirmed at following control points: Bezdan for NO3–-N, Ptot and BOD5; Bogojevo for NO3–-N, Ptot, COD and BOD5; Novi Sad for Ptot, BOD5 and COD; Slankamen for BOD5 and COD; Smederevo for NO3–-N and COD; Banatska Palanka for NO3–-N. Slight deterioration of water quality was confirmed only in two cases, at the Zemun and Smederevo where DO was decreasing. Water quality for the examined period was stable and can be characterised as excellent and/or very good (class I or class II). Results emphasise fact that water quality trends monitoring reveals river sectors where the process of water quality degradation is ongoing. Timely detected critical river sectors can draw the attention of decision-makers, who can improve the existing legislation that would lead to water quality improvement.

20

Analysis of trend rainfall: Case of North-Eastern Algeria

63%

Mrad D. , Djebbar Y. , Hammar Y.

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