Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 102

Liczba wyników na stronie
first rewind previous Strona / 6 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  drought
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 6 next fast forward last
EN
Morocco is currently facing significant challenges due to the ever–changing climate, with its critical water sources crucial for agriculture, economy, and daily life being greatly affected. In order to thoroughly understand the impact of climate change on the Ghis–Nekor watershed, an in–depth study spanning 38 years (1978–2016) was conducted. This involved examining the meteorological data from three stations and utilizing advanced indices, such as SPI, RDI, and DI. The findings of this study revealed prominent shifts in precipitation patterns, indicating a vulnerability in the region. While there was a general increase in annual rainfall during the specified time period, a sharp decline was observed post–2008. Further analysis of drought confirmed the presence of persistent dry spells and recurring episodes, highlighting the urgent need for effective water management strategies. These crucial findings must be considered by decision–makers for successful climate adaptation, emphasizing the key role played by this study in mitigating the effects of climate change.
EN
The Lamongan Regency is an area in East Java, Indonesia, which often experiences drought, especially in the south. The Corong River basin is located in the southern part of Lamongan, which supplies the irrigation area of the Gondang Reservoir. Drought monitoring in the Corong River basin is very important to ensure the sustainability of the agricultural regions. This study aims to analyse the causal relationship between meteorological and agricultural drought indices represented by standardised precipitation evapotranspiration index (SPEI) and standard normalisation difference vegetation index (NDVI), using time series regression. The correlation between NDVI and SPEI lag 4 has the largest correlation test results between NDVI and SPEI lag, which is 0.41. This suggests that the previous four months of meteorological drought impacted the current agricultural drought. A time series regression model strengthens the results, which show a causal relationship between NDVI and SPEI lag. According to the NDVI-SPEI-1 lag 4 time series model, NDVI was influenced by NDVI in the previous 12 periods, and SPEI-1 in the last four periods had a determinant coefficient value of 0.4. This shows that the causal model between SPEI-1 and NDVI shows a fairly strong relationship for drought management in agricultural areas (irrigated areas) and is considered a reliable and effective tool in determining the severity and duration of drought in the study area.
EN
Drought is characterised as a recurring climatic phenomenon with prolonged duration, affecting land through below-average rainfall and often accompanied by high temperatures. When the available water falls below the optimum level, water deficit or water stress arises, disrupting normal plant processes. This condition poses challenges for plant growth and development as it hampers the internal water transport, induces stomatal closure, and limits access to photosynthetic resources. The study employed the annual sunflower as the experimental plant. The plants were cultivated in a controlled environment with a temperature ranging from 20 to 25°C and a humidity level of 55 to 60%, supplemented by MARS HYDRO artificial LED lighting set to a 12-h photoperiod. Radial changes in the plant stems were monitored using a DD-S type dendrometric sensor to measure radial fluctuations. The collected data were recorded in a dendrometric data logger DL 18. Data collection occurred at hourly intervals from February 20 to March 9, 2023. The nine plants were divided into three groups, each comprising three plants. All plants from groups 1 and 2 received irrigation at one-day intervals (group 1 - 80 cm3 per plant, group 2 - 40 cm3 per plant) and group 3 was not irrigated. Based on these findings, visible water stress was evident in the plants under experimental conditions. Consequently, continuous monitoring throughout the growing season will be essential to adjust the irrigation rate to meet the requirements of the plants.
EN
Drought is a large-scale disturbance that affects freshwater ecosystems worldwide. This recurrent phenomenon in Morocco, has experienced severe episodes during the last decade and has caused water stress in several aquatic ecosystems including the Youssef Ben Tachafine dam. Indeed, the volume of this reservoir has experienced its lowest historical hydrological level (12%) during the study period. To study the effects of water stress on water quality and planktonic community structure, water samples were collected from January 2019 to December 2020 at nine depths. The physicochemical parameters of the water were measured in parallel with the qualitative and quantitative study of the phytoplankton and zooplankton communities. The results obtained show a low planktonic diversity with only 43 phytoplanktonic species and 27 zooplanktonic species. The phytoplankton showed an almost permanent predominance of Chlorophyceae (85%), dominated by Closterium pronum, followed by Diatomophyceae (9.5%), dominated by Cyclotella ocellata. Rotifers represent the most abundant zooplanktonic group during the study period with two dominant species (Keratella tecta and Polyarthra vulgaris). Statistical analysis of the data from this study, using R software, revealed a negative correlation between Cladoceran species, Copepods and the diatom Cyclotella ocellata on the one hand and the decrease in water level, temperature and enrichment of the environment in nutrients and phytoplanktonic biomass on the other. This study shows that the effect of the extreme drought, which the Youssef Ben Tachafine dam has experienced, has altered the diversity and structure of planktonic communities, which threatens the sustainability of ecological services of this ecosystem.
EN
The area of Agadir, which is situated on Morocco's southern Atlantic coast, is characterized by an arid climate, and has been strongly impacted by climate change. The purpose of this research is to assess observed and modeled drought variability in time, on the basis of rainfall time series for the periods 1973–2020, and 2022–2099 by use of SPI, short for Standardized Precipitation Index. Findings from the SPI analysis show that the years from 1981 to 1986 were the driest as per the instrumental record. Future SPI projections indicate that the area under study will face several prolonged drought and wet periods between 2022 and 2099. The longest drought will take place from 2090 to 2093. Analysis of the relationship between rainfall in Agadir and North Atlantic Oscillation (NAO), is also studied especially for the winter months. The results of the study will provide a basis for drought surveillance and hydrometeorological studies, in addition to initiating the desired managment of environment in this area.
EN
Like most of the countries of the African continent and the MENA, Morocco has experienced alternating wet and dry periods for several decades and is still confronted with the effects of unstable climate change due to the specificities conferred by its geographical position and the diversity of its ecosystems. It is one of the countries most affected by desertification, with an arid and semi-arid climate covering more than 93% of its territory. Indeed, the Upper Moulouya watershed has been exposed to severe droughts several times in recent decades. The spatial and temporal distribution of drought episodes in this watershed is studied over a 91-year period between 1931 and 2022. In order to characterize and evaluate the severity and sustainability of drought in this watershed, four indices were used and applied in this study, as they have advantages in terms of statistical consistency and have the capacity to describe, through different time scales (short, medium and long) the impacts of the climatic drought in question. These are the Standardized Precipitation Index SPI, RDI, RI and DI. The annual rainfall series at the eight meteorological stations of the said watershed show irregularities and very marked spatial and temporal variability with a generally decreasing trend. The SPI calculation results obtained show a heterogeneous distribution of SPI values throughout the watershed area. The analysis of the graphical illustrations of this index allowed to highlight an important fluctuation of the dry and wet periods with a strong dominance and tendency to drought with the order of 51% in the stations of Midelt, and Ansegmir, 52% in the station of Zaida, 59% in the stations of Tabouazant, Barrage (Dam) Enjil and El Aouia, 58% in the station of Louggagh, 47% in the station of Anzar Oufounes. The analysis of the results of the of the drought indices RDI, RI and DI at the level of this watershed also made it possible to highlight the existence of numerous drought sequences alternating with other wet sequences and indicates a dominance of dry years, perfectly remarkable during the period 1976-93. The most important dry episode, in number of successive years, was recorded at the Ansegmir station from 1976-89 and the most important rainy episode was recorded at the Midelt station from 1966-76. The years of the 2015-2022 series show an overall persistent decrease in rainfall, thus allowing the installation of a severe drought episode. The trend in the entire watershed is a decrease in rainfall and the installation of mild, moderate and severe drought episodes of varying length and duration.
EN
Over the past years, alterations in the environment have had an adverse impact on the global agricultural system, leading to difficulties in plant growth, physiology, and productivity due to non-living factors. These difficulties pose a significant risk to both global food security and agricultural advancement, necessitating innovative methods for long-term sustainability. Nanotechnology has emerged as a promising solution to address these difficulties by utilizing nanoscale products like nanofertilizers, nanofungicides, nanoherbicides, and nanopesticides. Nanoparticles provide distinct advantages in agriculture due to their small size, ability to easily penetrate cellular barriers, and efficient absorption by plants. Numerous studies have demonstrated that the application of nanoparticles can improve both the quantity and quality of crop yields, even when faced with various biological and environmental pressures. This research study primarily focuses on investigating the impact of non-living pressures on plants and examining how nanoparticles can help alleviate these effects. Additionally, it explores the molecular, metabolic, and anatomical adaptations that plants undergo to thrive in challenging environments. Nonetheless, it is essential to acknowledge that the widespread utilization of nanotechnology raises concerns regarding potential risks to the environment and human health.
EN
Climate change causes various events, such as El Niño , and we experience their larger frequency. This study based on a quantitative approach uses observation data from the Umbu Mehang Kunda Meteorological Station and the Ocean Niño Index (ONI). As a result, East Sumba, which has an arid climate, has more challenges in dealing with drought and water deficits during El Niño. This study identifies rainfall when the El Niño phenomenon takes place in East Sumba through data contributing to the ONI value and dry day series from 1982 to 2019. The analysis was carried out by reviewing these data descriptively and supported by previous literature studies. The research found that there was a decrease in the accumulative total rainfall in El Niño years. The annual rainfall in the last six El Niño events is lower than the annual rainfall in the first six El Niño events. The dry day series is dominated by an extreme drought (>60 days) which generally occurs from July to October. This drought clearly has a major impact on livelihoods and causes difficulties in agriculture as well as access to freshwater. This results in crop failure, food shortages, and decreased income. The phenomenon triggers price inflation in the market and potential increase in poverty, hunger, and pushes the country further away from the first and second Sustainable Development Goals. This phenomenon and problems related to it need to be dealt with by multistakeholders.
EN
The scarcity of annual rainfall, which sometimes spreads over successive years, causes persistent droughts. In order to study the drought severity on the Algerian steppe, we analysed precipitation data (1985-2015) from the weather stations of Ain Sefra, El Bayadh, Tiaret and Djelfa, using drought meteorological indices: the mean deviation, the standardised precipitation index, the rainfall index and the frequency analysis of the rainfall series. Thus, we adopted the diachronic study by satellite remote sensing for the years 2002 (the driest year) and 2009 (the wettest year), which allowed us to better understand the evolution of the steppe rangelands surface and to better interpret their spatial-temporal changes. Drought, as determined by the mean deviation index, occurred during two periods (in sequence and corresponds to 55% the sequences of deficit years), one over 12 years (from 1994/1993 to 2006/2005) and the other over 5 years (1985-1990) and with isolated years. The results of the diachronic study of the vegetation change demonstrate the obvious divergence of the vegetation cover between 2002 and 2009. Drought has impacts on vegetation composition, growth, productivity, structure and functioning of ecosystems, which limits regeneration of vegetation cover.
EN
In Vietnam, drought has been occurring persistently and in very complicated patterns, with a great impact on the water, energy, and food security nexus and regional development sustainability. The uncertainty surrounding annual water resources in combination with the low reliability of interbasin water transfer (IBWT) operations is the key driver of water deficits in several affected regions. This study aims to assess the impacts of four big IBWT projects in the Central Highlands of Vietnam, based on a proposed matrix of five evaluation criteria to quantify related impacts and to draw out lessons learned for future development of IBWT. The proposed criteria matrix was formulated on the basis of intensive reviews of IBWT assessments worldwide and relevant Vietnamese laws in force. The impacts were analysed and quantified mainly based on assessment of their operational database and water balance simulations for donor and recipient river basins in current and future states. The results show that the studied IBWT projects did not fully satisfy the proposed criteria set, all project did not meet the criteria of benefit sharing and information transparency; noticeably the Don Duong project fulfilled only one from five. Four lessons were determined for proper planning in river basins, flexibility in system design for unknown future, inadequate environmental impact assessment and delay in enactment of policies for IBWT project management. The results provide sound knowledge to revise the existing projects in the Central Highlands and procedures for impact assessment and approval of new IBWT systems.
EN
Water deficit is one of the major environmental issues affecting biodiversity. Drought-related works are conducted to explore the mechanisms involved in drought vulnerability or resistance and to adopt the most advantageous tool to monitor these changes. Field spectroscopy, an accessory tool of remote sensing, evaluates the reflectance to collect continuous spectrum from materials. In the conducted study, the potential of using UV-Near infrared (NIR) spectroscopy as a non-destructive and reliable approach in monitoring of drought effects on three Medicinal and Aromatic Plants species (MAPs): Lavandula stoechas, Cistus laurifolius and Pistacia lentiscus from Northern Morocco during dry (July 2021) and wet (March 2022) period was addressed. It was found that Lavandula stoechas species is more impacted by water deficit than Cistus laurifolius and Pistacia lentiscus. Indeed, this species has a lower reflectance in Visible and NIR regions of the spectrum after a period of drought and therefore a higher vulnerability to water deficit than the other two species.
PL
W pracy wyjaśniono, czym jest susza w wodach podziemnych. Podano, od czego zależy wrażliwość danego terenu na niżówkę hydrogeologiczną zarówno w aspekcie uwarunkowań naturalnych, jak również technicznych. Opisano możliwe negatywne skutki niżówki hydrogeologicznej i działania, jakimi można im przeciwdziałać. Podniesiono kwestię właściwej lokalizacji sztucznych, powierzchniowych zbiorników wodnych w aspekcie wód podziemnych i realizacji zadań tzw. „małej retencji", przy czym zwrócono uwagę na kluczową rolę przepływowości zbiornika. Wskazano na zalety magazynowania wody w warstwach wodonośnych.
EN
The article describes the groundwater drought phenomenon. The author explains what determines the vulnerability of a given area to groundwater drought, both in terms of natural and technical conditions. The paper describes the possible negative effects of periods of decreased groundwater levels and the actions that can be used to counter them. The article also raises the subject of adequate location of artificial surface water reservoirs in terms of groundwater recourses and main tasks of small water retention. Particular attention was addressed to the key role of flow reservoirs. The paper indicates the benefits of water storage in aquifers.
PL
Susza jest najdroższym zagrożeniem naturalnym na świecie. Wystąpieniu suszy nie można zapobiec, ale dzięki zrozumieniu mechanizmów jej powstawania oraz określeniu warunków sprzyjających jej rozprzestrzenianiu się można wpływać na zmniejszanie lub ograniczanie jej skutków. Obserwowana zmiana klimatu i świadomość konsekwencji, w tym wzrostu częstotliwości występowania zjawisk ekstremalnych, stwarza potrzebę wdrażania działań adaptacyjnych. Działania te pozwolą na dostosowanie się do zachodzących zmian w środowisku naturalnym oraz ograniczenie konsekwencji związanych z występowaniem suszy.
EN
Drought is the most expensive natural hazard in the world. Drought cannot be prevented but, understanding the mechanisms of its occurrence and determining the conditions contributing to its propagation, we can limit or mitigate its effects. The observed climate change and awareness of the consequences, including an increase in the frequency of extreme phenomena, creates the need to implement adaptation measures. They will allow for an adaptation to changes occurring in the natural environment and reduction of drought consequences.
PL
Ostatnie lata to obraz systematycznie pogarszającej się zieleni miejskiej. Chorują i zamierają zarówno dojrzałe drzewa, jak i nowe nasadzenia, które trudno utrzymać w zadowalającym stanie zdrowotnym, mimo intensywnych nakładów pielęgnacyjnych. Przyczyn tego upatruje się w trudnych warunkach siedliskowych na obszarach zurbanizowanych oraz w miejskich zanieczyszczeniach. Mówi się także wiele o niekorzystnym wpływie stosowania soli do odladzania nawierzchni w okresie zimowym. Jednak najpoważniejszą przyczyną pogarszającego się stanu zieleni generalnie, a zieleni miejskiej szczególnie, jest susza.
EN
The purpose of this study is to develop mathematical models based on artificial intelligence: Models based on the support vectors regression (SVR) for drought forecast in the Ansegmir watershed (Upper Moulouya, Morocco). This study focuses on the prediction of the temporal aspect of the two drought indices (standardized precipitation index – SPI and standardized precipitation-evapotranspiration index – SPEI) using six hydro-climatic variables relating to the period 1979–2013. The model SVR3-SPI: RBF, ε = 0.004, C = 20 and γ = 1.7 for the index SPI, and the model SVR3-SPEI: RBF ε = 0.004, C = 40 and γ = 0.167 for the SPEI index are significantly better in comparison to other models SVR1, SVR2 and SVR4. The SVR model for the SPI index gave a correlation coefficient of R = 0.92, MSE = 0.17 and MAE = 0.329 for the learning phase and R = 0.90, MSE = 0.18 and MAE = 0.313 for the testing phase. As for the SPEI index, the overlay is slightly poorer only in the case of the SPI index between the observed values and the predicted ones by the SVR model. It shows a very small gap between the observed and predicted values. The correlation coefficients R = 0.88 for the learning, R = 0.86 for testing remain higher and corresponding to a quadratic error average MSE = 0.21 and MAE = 0.351 for the learning and MSE = 0.21 and MAE = 0.350 for the testing phase. The prediction of drought by SVR model remain useful and would be extremely important for drought risk management.
EN
Today’s agriculture is facing a range of challenges, the most important of which is the adjustment to the changing climate. In this context, water management is particularly vital. Droughts in Poland are becoming more and more frequent. That fact adds to the significance of irrigation and drainage systems. This paper is an attempt at diagnosing the condition of (in 2016) and changes in (over the period of 2006–2016) irrigation and drainage systems in the Kujawsko-Pomorskie Voivodship (analysed by communes, until 2016 – according to Local Administrative Units – LAU level 2). The multidirectional analysis involves a comprehensive description of ameliorated lands, including the allocation of the EU funds dedicated for the support of flood protection and land improvement ventures. It has been demonstrated that the present condition of land improvement does not reflect the needs of the agriculture in the studied area and that the changes implemented on the ongoing basis fail to make the situation better. In 2016, slightly over 40% of agricultural acreage was ameliorated, while the level at which land improvement needs would be satisfied approximated 70%. In over 1/5 of the ameliorated area, facilities needed reconstruction or modernisation. Drainage systems were in the majority, which indicates that the current needs, i.e. water scarcity, are not addressed.
EN
The drought ranked first in terms the natural hazard characteristics and impacts followed by tropical cyclones, regional floods, earthquakes, and volcanoes. Drought monitoring is an important aspect of drought risk management and the assessment of drought is usually done through using various drought indices. The western region in Algeria is the most affected by the drought since the middle of the 70s.The current research focuses on the analysis and comparison of four meteorological drought indices (standardized precipitation index – SPI, percent of normal index – PN, decile index – DI, and rainfall anomaly index – RAI) in the Tafna basin for different time scales (annual, seasonal, and monthly) during 1979–2011. The results showed that the SPI and DI have similar frequencies for dry and wet categories. The RAI and PN were able to detect more drought categories. Meanwhile, all indices have strong positive correlations between each other, especially with Spearman correlation tests (0.99; 1.0), the meteorological drought indices almost showed consistent and similar results in the study area. It was determined in 1982 as the driest year and 2008 as the wettest year in the period of the study. The analysis of the trend was based on the test of Mann–Kendall (MK), a positive trend of the indices were detected on a monthly scale, this increasing of indices trend represent the increasing of the wet categories which explains the increasing trend of the rainfall in the last 2000s. These results overview of the understanding of drought trends in the region is crucial for making strategies and assist in decision making for water resources management and reducing vulnerability to drought.
EN
Suitable soil and environmental conditions are the main prerequisites for successful growth of plants. Generally, all soil properties are substantially affected by textural composition. Therefore, the objective of the study was to test the interrelationships between particle size distribution and such physical soil properties, which usually predetermine the survival/death of plants, since they significantly affect the content and availability of water and air. Textural composition and physical soil properties were studied in profiles under monocultures of selected exotic trees in Arboretum Mlyňany, Slovakia. The results showed that medium-textured dominated in topsoils, whereas heavy-textured classes were dominant in luvic and stagnic horizons. Evaluation of entire profiles had confirmed standard, expected relationships between the individual grain fractions and soil physical properties. However, differences have occurred when the correlations between texture and physical properties in individual horizons were evaluated. Considering entire soil profiles, increased sand content significantly supported drainage of rainwater and soil aeration; silt contributed to increase the total porosity and aeration as well as available water capacity; clay contributed to the decrease in the available water capacity, total, and particularly coarse porosity and aeration, and to rise water retention, as well as the values of the wilting point. The results showed silt as key fraction providing suitable hydrophysical properties for the survival and growth of trees introduced in Arboretum. In compacted luvic and stagnic horizons, silt was significantly involved in the formation of total, and particularly coarse porosity and thereby increase soil aeration, while conversely, in loose topsoils just silt fraction significantly contributed to the reduction of coarse pores and increase of fine capillary pores and therefore water retention. In loose eluvial horizons, the silt contributed to significant increases in capillary porosity and water availability, which is essential in terms of meeting the plant needs.
EN
The main objective was to explore the connection between flood and drought hazards and their impact on crop land and human migration. The Flood and Drought effect on Cropland Index (FDCI), hot spot analysis and the Global Regression Analysis method was applied for the identification of the relationship between human migration and flood and drought hazards. The spatial pattern and hot and cold spots of FDCI, spatial autocorrelation and Getis-OrdGi* statistic techniques were used respectively. The FDCI was taken as an explanatory variable and human migration was taken as a dependent variable in the environment of the geographically weighted regression (GWR) model which was applied to measure the impact of flood and drought hazards on human migration. FDCI suggests a z-score of 4.9, which shows that the impact of flood and drought frequency on crop land is highly clustered. In the case of the hot spots analysis, out of seventy districts in Uttar Pradesh twenty-one were classified as hot spot and eight were classified as cold spots with a confidence level of 90 to 99%. Hot spot indicate maximum and cold spots show minimum impact of flood and drought hazards on crop land. The impact of flood and drought hazards on human migration show that there are fourteen districts where migration out is far more than predicted while there are ten districts where migration out is far lower.
PL
Na problem suszy w zieleni miejskiej można odpowiedzieć inaczej niż tylko sadząc gatunki dobrze radzące sobie z niedostatkiem wody, ale także wykorzystując środki agrotechniczne i modyfikując sposoby pielęgnacji roślin.
first rewind previous Strona / 6 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.