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EN
Evapotranspiration (ET) plays a key role in water cycle and energy balance, and the construction of large areas of vegetation in the Yellow River Basin (YRB) will cause an increase in regional ET and changes in water use in the basin. Based on GLEAM evapotranspiration products, meteorological stations and land use data, this study used slope trend analysis, Mann-Kendall (M-K) test and partial correlation analysis to analyse changes in evapotranspiration and water use in the YRB before and after reforestation from 1980 to 2019. The results showed that the annual average ET of the YRB from 1980 to 2019 ranged from 363 to 447 mm with an average change rate of 10.2 mm/10a. The actual evapotranspiration/potential evapotranspiration (ET/PET) growth rate of the YRB decreased after the Grain for Green Project (GGP), and the actual evapotranspiration/precipitation (ET/P) decreased extremely significantly. Water use efficiency in the YRB was significantly reduced, and grassland was subjected to greater water stress. This study provides scientific support for future water balance, landscape restoration, ecological protection and quality development of the YRB.
EN
Satellite-based irrigation performance is a valuable tool for improving yields in irrigated areas across the world and requires adequate land for long-term development. This study aimed to increase irrigation performance and yield gap variation of rainfed crops using the database of FAO’s Water Productivity Open Access Portal (WaPOR) and the Global Yield Gap Atlas. The evapotranspiration (ET) performance of irrigation is expressed in equity (CV of ET), reliability, adequacy (CV of ET), and water productivity (kg∙m-3). The rainfed crops are interpreted in terms of metric tonnes/ha. Specifically, 20,325 km2 of suitable pastoral land across eight sub-classes was converted to rainfed rice, sugarcane, maize, and vegetable crops. Results showed that the R2 value was 0.97 at Baro Itang and -0.99 at Sor Metu, with the Baro Gambella sub-catchment having the largest yield gap of 4.435.2, 8.870.4, and 10.080∙106 kg when the yield increased by 1/3, 2/3, and 3/4. On the other hand, Gumero Gore had the smallest yield gap of 10,690, 29,700, and 33,750 kg, respectively. The management regime was 2.87, 0.87, and 0.35 kg∙m-3 for growers in the estate, farmer association, and individual, respectively. The study concludes that no single irrigation technique can be considered the best, and a thorough analysis of spatiotemporal variation of the irrigation performance indicators and the yield gap in the water-scarce lower Baro watershed is required.
EN
A machine learning model was developed to support irrigation decisions. The field research was conducted on ‘Gala’ apple trees. For each week during the growing seasons (2009-2013), the following parameters were determined: precipitation, evapotranspiration (Penman-Monteith formula), crop (apple) evapotranspiration, climatic water balance, crop (apple) water balance (AWB), cumulative climatic water balance (determined weekly, ∑CWB), cumulative apple water balance (∑AWB), week number from full bloom, and nominal classification variable: irrigation, no irrigation. Statistical analyses were performed with the use of the WEKA 3.9 application software. The attribute evaluator was performed using Correlation Attribute Eval with the Ranker Search Method. Due to its highest accuracy, the final analyses were performed using the WEKA classifier package with the J48graft algorithm. For each of the analysed growing seasons, different correlations were found between the water balance determined for apple trees and the actual water balance of the soil layer (10-30 cm). The model made correct decisions in 76.7% of the instances when watering was needed and in 87.7% of the instances when watering was not needed. The root of the classification tree was the AWB determined for individual weeks of the growing season. The high places in the tree hierarchy were occupied by the nodes defining the elapsed time of the growing season, the values of ∑CWB and ∑AWB.
EN
The treatment of wastewater in small rural settlements requires special attention in the choice of the purification technique to be used, insofar as experience has shown that the technologies initially developed for the urban environment do not prove to be as effective for the rural environment. The current trend tends towards autonomous systems. Among these systems are Floating treatment wetlands. The objective of this study was to evaluate the evapotranspiration and the performances of two emerging plants; Cyperus papyrus and Typha latifolia. The experimental device was composed of three test tanks whose dimensions were: length = 1 m, width = 1 m and water height = 0.85 m – two tanks with emerging plants (Cyperus papyrus and Typha latifolia) and a control tank without vegetation. The monitoring of the evolution of plant evapotranspiration and the evaporation of the control tank for different periods and temperatures showed that the volumes of water lost were respectively for Cyperus papyrus, Typha latifolia and control tank: (1) 130 liters, 230 liters and 5 liters for two days at an average temperature of 26.3 °C; (2) 125 liters, 150 liters and 0 liters for two days at an average temperature of 26.7 °C; (3) 240 liters, 280 liters and 5 liters for three days at an average temperature of 27.3 °C; (4) 140 liters, 260 liters and 10 liters for two days at an average temperature of 26 °C; (5) 140 liters, 240 liters and 5 liters for two days at an average temperature of 27.3 °C; (6) 260 liters, 550 liters and 10 liters for four days at an average temperature of 28.6 °C. It turned out that the presence of plants as well as the temperature and the retention time in the tanks have a impact on the loss of water and more precisely those with emerging macrophytes. The present study has shown that the floating treatment wetlands planted with Cyperus papyrus and Typha latifolia can be used for wastewater treatment. Indeed, the removal efficiency in terms of COD, BOD5 and SS were respectively: 76%, 75.3% and 95.90% for Cyperus papyrus and 70.45%, 66.5% and 93.70% for Typha latifolia.
PL
Celem pracy było określenie różnic potrzeb deszczowania trawnika wynikających z niejednorodności topograficznej miasta Bydgoszczy i zróżnicowanych pod względem zagospodarowania terenów zamiejskich. Pomiary meteorologiczne prowadzono w okresie od maja do września na terenach zróżnicowanych pod względem stopnia urbanizacji i formy pokrycia terenu: centrum dużego miasta, peryferia miejskie i obszar użytkowany rolniczo. Na podstawie wielkości obliczonych potrzeb wodnych trawnika określono zakres deficytów opadów w okresie wegetacji roślin. Stwierdzono, że sumy opadów sezonowych w porównywanych lokalizacjach kształtowały się na podobnym poziomie, jednakże zaobserwowano dużą zmienność czasową tego wskaźnika w poszczególnych sezonach. Pod względem warunków ewaporometrycznych zaobserwowano wyraźne różnice pomiędzy analizowanymi lokalizacjami. Średnio, największe sumy ewapotranspiracji wskaźnikowej wyznaczono dla centrum miasta, co jest efektem powstającego na tym obszarze zjawiska „miejskiej wyspy ciepła”. Natomiast najmniejsze straty wody na skutek ewapotranspiracji wystąpiły na terenach wiejskich. Wyniki przeprowadzonej analizy pozwoliły stwierdzić, że potrzeby deszczowania trawnika cechowała zarówno zmienność czasowa jak i przestrzenna. Zdecydowanie największe potrzeby deszczowania wystąpiły w warunkach miejskich, mniejsze na terenach wiejskich użytkowanych rolniczo, a najmniejsze na obrzeżach Bydgoszczy.
EN
The study aimed to determine the differences in lawn irrigation needs resulting from the topographical heterogeneity of the city of Bydgoszcz and surrounding areas. To gather the data, meteorological measurements were carried out in the period from May to September 2012-2014, in areas diversified in terms of the degree of urbanization and land cover: the center of a large city, urban peripheries and rural area. Based on the calculated water needs of the lawn, the range of rainfall deficits during the lawn growing period was determined. It was found that seasonal rainfall totals in the compared locations were at a similar level, but a large temporal variability of this indicator was observed in individual seasons. In terms of evapotranspiration, clear differences were noted between the analysed locations. On average, the highest amounts of potential evapotranspiration were found in the city center, which may be the result of the urban heat island phenomenon forming over this area. However, the lowest water loss due to evapotranspiration took place in the rural area. As a result of these, the analysis showed that the lawn's irrigation needs were characterized by both temporal and spatial variability. By far the greatest irrigation needs occurred in urban space, lower in rural areas, while the lowest on the outskirts of the city, in the Fordon district.
EN
Global gridded products efficiency in closing water balance models: various modeling scenarios for behavioral assessments
EN
The existing researches for leaf area index (LAI)-based Penman–Monteith evapotranspiration (ET) model (PML) are mostly carried out at yearly scale and the analysis of effects of seasonal change and different underlying surface conditions on model parameters is scarce. This study emphasizes on the influences of seasonal change and diverse land surface conditions on ET by optimizing the sensitive parameters, namely soil evaporation coefficient f and maximum stomatal conductance gsx, with particle swarm algorithm. This analysis is based on the observations of eight flux stations in China. The model performance is reasonable with a best Pearson r of 0.87. The seasonal calibration results indicate parameters change evidently in different seasons and have obvious spatial heterogeneity. The seasonal calibration method has an obvious effect on improving the ET accuracy in spring, which is mostly influenced by regional temperature and relative humidity. This study further demonstrates the need to dynamically adjust model parameters over time with PML model for evapotranspiration simulations, rather than simply setting these parameters to constants depended on subsurface conditions such as land use type.
EN
Optimal estimation of water balance components at the local and regional scales is essential for many applications such as integrated water resources management, hydrogeological modelling and irrigation scheduling. Evapotranspiration is a very important component of the hydrological cycle at the soil surface, particularly in arid and semi-arid lands. Mapping evapotranspiration at high resolution with internalised calibration (METRIC), trapezoid interpolation model (TIM), two-source energy balance (TSEB), and soil-plant-atmosphere and remote sensing evapotranspiration (SPARSE) models were applied using Landsat 8 images for four dates during 2014-2015 and meteorological data. Surface energy maps were then generated. Latent heat flux estimated by four models was then compared and evaluated with those measured by applying the method of Bowen ratio for the various days. In warm periods with high water stress differences and with important surface temperature differences, METRIC proves to be the most robust with the root-mean-square error (RMSE) less than 40 W∙m-2. However, during the periods with no significant surface temperature and soil humidity differences, SPARSE model is superior with the RMSE of 35 W∙m-2. The results of TIM are close to METRIC, since both models are sensitive to the difference in surface temperature. However, SPARSE remains reliable with the RMSE of 55 W∙m-2 unlike TSEB, which has a large deviation from the other models. On the other hand, during the days when the temperature difference is small, SPARSE and TSEB are superior, with a clear advantage of SPARSE serial version, where temperature differences are less important.
EN
Drought is regarded as one of the environmental constraints threatening agriculture worldwide. Melatonin is a pleiotropic molecule prevalent in plants capable of promoting plant endogenous resilience to many environmental challenges including drought. Banana is an important staple food consumed in developing countries especially in Africa. In this research, we studied the role of melatonin in the growth of bananas subjected to drought under the Egyptian semi-arid conditions. To achieve this objective, a field experiment on banana (Musa spp., cv. Williams) mother plants and first ratoon was conducted on a private farm for two seasons - 2019 and 2020. Three irrigation treatments, 100, 90 and 80% irrigation water requirements (IWR) were used in conjunction with four concentrations of melatonin as a foliar spray (0 μmol, 40 μmol, 60 μmol, and 80 μmol) to determine the effect of both treatments on banana plant performance under drought. The results showed that there was a substantial difference between treatments, with the foliar application of melatonin at 80 μmol concentration improving most of the yield attributes, relative water content, total chlorophyll and proline with water deficit. However, the foliar application of the molecule lowered the biochemical characteristics mostly at 80% IWR under the Egyptian semi-arid conditions. Overall, there was a concentration-dependent response with regards to IWR for the two seasons 2019 and 2020.
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EN
Atmospheric precipitation is the major input to the soil water balance. Its amount, intensity, and temporal distribution have an indubitable influence on soil moisture. The aim of the study (conducted in the years 2010-2013) was to evaluate soil water balance in an apple orchard as determined by daily rainfall. The amount and intensity of rainfall and daily evapotranspiration were measured using an automatic weather station. Changes in soil water content was carried out using capacitance probes placed at a depth of 20, 40 and 60 cm. The most common were single events of rainfall of up to 0.2 mm, while 1.3-3.6 mm rains delivered the greatest amount of water. A significant correlation was found between the amount of daily rainfall and changes in water content of individual soil layers. The 15-45 cm and 15-65 cm layers accumulated the greatest amount of high rainfall. The study showed a significant influence of the initial soil moisture on changes in the water content of the analysed layers of the soil profile. The lower its initial moisture content was, the more rainwater it was able to accumulate.
EN
Evapotranspiration (ET) is one of the key components of the hydrological cycle, and its accurate estimation is very important in agricultural usages. In this study, actual daily ET (ETa) from the Surface Energy Balance Algorithm for Land (SEBAL) and Mapping Evapotranspiration with Internalized Calibration/Earth Engine Evapotranspiration Flux (EEFLux) algorithms were used to compare the relative performance of the algorithms for the Landsat 8 images during the maize growth period. The results indicated that ETa was low at the beginning of the growing season and then came up to the middle of the growing season and then decreased due to decreasing temperature as well as changes in maize cover. The EEFLux algorithm has estimated about 7.71% of daily ET more than the SEBAL algorithm at the Arak maize farm. The results of performance evaluation showed that root mean squared error (RMSE), Nash–Sutclife coefficient of efficiency (NSE), percent bias error (PBIAS), and coefficient of determination (R2 ) criteria were obtained 0.711, 0.807, 7.398, and 0.885, respectively, based on the EEFLux algorithm and for SEBAL algorithm were equal to 1.046, 0.582, 15.080, and 0.793, respectively. According to the Taylor diagrams and observed data (lysimeter data), the EEFLux algorithm was closer to measured ETa values and had a higher correlation and a less standard deviation than the SEBAL algorithm. Therefore, the EEFLux algorithm had better estimation than the SEBAL algorithm.
EN
The purpose of this study was to estimate the water needs of grapevines in central Poland in 1981-2010. Water needs were calculated by the plant coefficients, which were assumed according to the Doorenbos and Pruitt method. Reference evapotranspiration was assessed by the Blaney-Criddle’s equation, modified for Polish conditions. Rainfall deficit with the occurrence probability of normal, medium dry and very dry years was determined by the Ostromęcki’s method. Water needs of grapevines during the growing season was 434 mm. Upward time trend in the water needs both in the periods May-October and June-August was estimated. Temporal variability in the water needs was significant for most of the provinces. The rainfall deficit was recorded with the occurrence probability of normal as well as medium or very dry years in the entire study area. Due to climate changes, vineyards will require irrigation in the near future. This research significantly broadens and refines the knowledge about the water needs of grapevines in central Poland, which will allow the design of resource-efficient irrigation programs for grapevines in the studied region of Poland.
EN
Due to the scarcity of water on the globe today, it is considered as a valuable natural resource. This requires intensive and applied research to preserve it, and this, in turn, requires the design of smart irrigation systems that use water according to the actual needs of plants and with the least possible waste. Currently, plants irrigation all over the world consumes most of the freshwater that should be used in other more important areas. The commercial irrigation water controllers that are widely used in the world do not fulfill their intended purpose of saving the amount of irrigation water. The development and lower price of PLC have made it possible to use them as standalone controllers for smart and economical irrigation. In this paper a PLC type (s7-200) was used to control daily pulsed irrigation amounts according to actual transpiration ETo, using the Hargreaves-Samani method. Once ETo is calculated by the PLC, it begins to manage the timing of the irrigation system pulses as per the commands given by its program depending on the calculated values of the ETo.
PL
Ze względu na niedostatek wody na świecie jest dziś uważany za cenny zasób naturalny. Obecnie nawadnianie roślin na całym świecie pochłania większość słodkiej wody, która powinna zostać wykorzystana w innych, ważniejszych obszarach. Komercyjne sterowniki wody do nawadniania, które są szeroko stosowane na świecie, nie spełniają swojego zamierzonego celu, jakim jest oszczędzanie ilości wody do nawadniania. Rozwój i niższa cena programowalnych sterowników logicznych (PLC) umożliwiły wykorzystanie ich jako samodzielnych sterowników do inteligentnego i ekonomicznego nawadniania. W tej pracy zastosowano PLC typu (s7-200) do kontroli dziennych pulsacyjnych ilości irygacji zgodnie z rzeczywistą transpiracją (ETo), przy użyciu metody Hargreaves-Samani. Po obliczeniu ETo przez PLC, zaczyna on zarządzać synchronizacją impulsów systemu irygacyjnego zgodnie z poleceniami wydanymi przez jego program w zależności od obliczonych wartości ETo.
EN
According to the SRES A1B climate change scenario, by the end of the 21st century temperature in Poland will increase by 2-4°C, no increase in precipitation totals is predicted. This will rise crop irrigation needs and necessity to develop irrigation systems. Due to increase in temperature and needs of sustainable agriculture development some changes in crop growing structure will occur. An increase interest in high protein crops cultivation has been noted last years and further extension of these acreage is foreseen. Identifying the future water needs of these plants is crucial for planning and implementing sustainable agricultural production. In the study, the impact of projected air temperaturę changes on soybean water needs, one of the most valuable high-protein crops, in 2021-2050 in the Kuyavia region in Poland was analysed. The calculations based on meteorological data collected in 1981-2010 were considered as the reference period. Potential evapotranspiration was adopted as a measure of crop water requirements. The potential evapotranspiration was estimated using the Penman-Monteith method and crop coefficient. Based on these estimations, it was found that in the forecast years the soybean water needs will increase by 5% in the growing period (from 21 April to 10 September), and by 8% in June-August. The highest monthly soybean water needs increase (by 15%) may occur in August. The predicted climate changes and the increase in the arable crops water requirements, may contribute to an increase in the irrigated area in the Kuyavia region and necessity of rational management of water resources.
EN
Global climate change has led to significant shifts in local climatic conditions of Ukraine with the trend to aridity aggravation. Sustainable crop production is at risk due to the aridity level increase. The study is aimed to evaluate aridity index in Ukraine (on the whole country and individual regions’ scales) and the needs in irrigation using hydro-meteorological data of the key regional stations for the periods of 1961-1990 and 2010-2020. The results of hydro-meteorological evaluation were supported by the data on the soil moisture regimes provided by Soil Explorer service. The general trend to aridity aggravation in Ukraine was proved. It was found out that modern climate in most territory of Ukraine is semi-arid, dry subhumid and humid zones are observed in the western regions only. Humid soil moisture regimes (ustic and udic) are observed in the West and the North of the country. As a result of combined analysis of both aridity index and soil moisture regimes the conclusion was drawn that 46.05% of Ukrainian croplands cannot provide sustainable crop production without irrigation, 42.65% need irrigation for the cultivation of crops with high water use, and just 11.30% of the arable land require little or no irrigation.
EN
At present, the sludge drying beds of the Kyiv wastewater treatment plants are operated as a sludge accumulator in an emergency mode, practically without free volume. The purpose of the work was to determine the equation for the evaporation losses calculation from sludge drying beds and the required free volume for sludge accumulation for the next 7 years. The required free volume was calculated using the water budget method which takes into account evaporation from the water surface and evapotranspiration during the vegetation. The total losses from sludge drying beds is 1076 mm/year in normal year and is 920 mm/year in a cold year. The required free volume was calculated considering the trend of increasing average temperature over the last decade and considering the significant environmental risk. A correction was made for one unfavourable year with cold summer and warm winter and an additional rain rate of 1% probability. The additional free volume required is 3.24 million m3 for 7 years if all three sludge drying beds are operated.
EN
The Venezia Islands are a very special area from the hydrological point of view due to its water mass changes. Regular floods results in the need for the regular monitoring of water mass changes. For this purpose, a Gravity Recovery and Climate Experiment mission (GRACE) can be used as a source of data. The aim of the paper is to compare the latest results of the new GRACE FO observations. The comparisons were carried out all over Venezia Island using the L3 level, RL06 release data obtained with spherical harmonics degree and order extension of up to 120, by the three most important computational centres: JPL, GFZ, CSR. Results are compared to an average month values of precipitation and evapotranspiration and tide gauge data in the nearby area. Based on the research, no dependence between TWS and evapotranspiration and evapotranspiration change were found.
EN
This paper simulates the responses of water budget components to doubled CO2 (2 × 378 ppm) concentration in the atmosphere with atmospheric and oceanic surface warming of 2°C. Simulations employed version 4.7 of the Regional Climate Model of the International Centre for Theoretical Physics (ICTP). Two six-year experiments were each repeated twice with the same model physics and parameterizations. The control experiment held the CO2 concentration at 378 ppm (no warming), while the other experiment specified doubled CO2 concentration and warming. The results showed a positive response (60-100% increase) to doubled CO2 for precipitation, runoff, and storage terms in Sierra Leone, Burkina Faso, Guinea Bissau, and the ocean area between 3 and 13°N. However, there was a negative response (up to 60%) for northern Senegal, southern Mali, and northern Nigeria. The reductions in water fluxes were observed mostly on the leeward side of the highlands. Evapotranspiration showed a negative response (1-20%) to doubled CO2 on the land north of 20°N. Burkina Faso and southern Mali responded oppositely to doubled CO2, despite their spatial proximity.
EN
Lysimeters represent the ideal tool for direct measurement of soil water balance components in soil profiles. Changes in the water content in a soil monolith can be measured with sufficient accuracy by the precise lysimeter weighing system. Water content changes in soil monolith as derived from lysimeter mass represent one of the basic water balance component. This paper deals with the development and comparison of individual soil water balance components in two different soil profiles from the Easter-Slovakian-Lowland. Two lysimeter vessels were filled monolithically with two different soil profiles covered with grass: one sandy soil profile from locality Poľany and one silty-loam soil profile from locality Vysoká nad Uhom. A constant groundwater level of 1 m below ground level was maintained in both soil profiles. Under the same meteorological conditions, all differences in the development of water balance components were caused only by the differences in soil profiles. The actual evapotranspiration and water flows at the bottom of the soil profiles were compared. Sandy soils are generally considered to be more prone to drought than silty-loam soils. Under the specific conditions of this experiment (maintaining a constant groundwater level) the opposite was shown, when the silty-loam soil profile was more prone to drought than sandy soil profile. Sandy soil profile from Poľany reacted more quickly to precipitation (or evaporation). Due to the higher hydraulic conductivity of the sandy soil compared to the silty-loamy soil, the groundwater level response to external stimuli was much faster.
EN
The lakes of the Powidzki Landscape Park (Gniezno Lakeland) are known for their natural and recreational values. The majority of them are located within two large glacial tunnel valleys, that in many places cut through several levels of till and inter-till aquifers. Regional hydraulic linkage systems are developed where surface water and groundwater remain in direct contact. Smaller water bodies occur between the lakes, in other tunnel valleys, in isolated meltwater basins, or in river valleys. These water bodies constitute local drainage bases. The existence in the area of such morphologically diverse lakes with different flow rates, varied morphology, and heterogeneous geological structure permitted tracing of the hydrodynamic dependencies of lake catchments of various types. Hydrogeological cross-sections, comparative analyses of structural maps for successive aquifers, bathymetric plans of lakes, and piezometric contour maps were prepared. Surface and groundwater level fluctuations were investigated, as well as their response to changing atmospheric conditions. Water balances of lakes were also determined for selected lake catchments. The study showed that all the lakes analysed are closely related to groundwater, and that the deepest ones reach lower aquifers. The majority of the lakes drain the aquifers, but some of the lakes feed them. Such a situation was documented in coastal wetlands and in the eastern part of the Park, affected by a depression cone associated with a nearby lignite opencast mine. The study showed that the deepest of the lakes analysed have a very wide catchment area of groundwater recharge, expanding beyond the boundaries of their surface catchment areas. This is important for the development of their resources, especially in periods of hydrogeological low flow.
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