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Green, Daniel, i Ian Pattison. "Christiansen uniformity revisited: Re-thinking uniformity assessment in rainfall simulator studies". CATENA 217 (październik 2022): 106424. http://dx.doi.org/10.1016/j.catena.2022.106424.
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Silveira, Alexandre, Jorge M. G. P. Isidoro, Fábio P. de Deus, Simone Siqueira dos Reis, Antônio Marciano da Silva, Flávio A. Gonçalves, Paulo Henrique Bretanha Junker Menezes i Rafael de O. Tiezzi. "Enhancing the spatial rainfall uniformity of pressurized nozzle simulators". Management of Environmental Quality: An International Journal 28, nr 1 (9.01.2017): 17–31. http://dx.doi.org/10.1108/meq-07-2015-0140.
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Purpose Rainfall simulators are used on experimental hydrology, in areas such as, e.g., urban drainage and soil erosion, with important timesaving when compared to real scale hydrological monitoring. The purpose of this paper is to contribute to increase the quality of rainfall simulation, namely, for its use with scaled physical models. Design/methodology/approach Two pressurized rainfall simulators are considered. M1 uses three HH-W 1/4 FullJet nozzles under an operating pressure of 166.76 kPa and was tested over a 4.00 m length by 2.00 m width V-shaped surface. M2 was prepared to produce artificial rainfall over an area of 10.00 m length by 10.00 m width. The spatial distribution of rainfall produced from a single nozzle was characterized in order to theoretically find the best positioning for nozzles to cover the full 100 m2 area with the best possible rainfall uniformity. Findings Experiments with M1 led to an average rainfall intensity of 76.77-82.25 mm h−1 with a 24.88 per cent variation coefficient and a Christiansen Uniformity Coefficient (CUC) of 78.86 per cent. The best result with M2 was an average rainfall intensity of 75.12-76.83 mm h−1 with a 21.23 per cent variation coefficient and a CUC of 83.05 per cent. Practical implications This study contributes to increase the quality of artificial rainfall produced by pressurized rainfall simulators. Originality/value M2 is the largest rainfall simulator known by the authors worldwide. Its use on rainfall-runoff studies (e.g. urban areas, erosion, pollutant transport) will allow for a better understanding of complex surface hydrology processes.
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Bateni, Norazlina, Sai Hin Lai, Frederik Josep Putuhena, Darrien Yau Seng Mah i Md Abdul Mannan. "A Rainfall Simulator Used for Testing of Hydrological Performances of Micro-Detention Permeable Pavement". International Journal of Engineering & Technology 7, nr 3.18 (2.08.2018): 44. http://dx.doi.org/10.14419/ijet.v7i3.18.16671.
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A rainfall simulator for laboratory experimentation is developed to test hydrological performances of micro-detention pond permeable pavement, MDPP. Rainfall characteristics consisting of rainfall intensity, spatial uniformity, raindrop size, and raindrop velocity show that natural rainfall is simulated with sufficient accuracy. The rainfall simulator used pressure nozzles to spray water for rainfall intensity from 40 to 220mm/hr. Uniformity distribution test gives coefficient of uniformity of 95% over an area of 1m2. The raindrops falling at velocity ranging from 0.5 to 15m/s with drop sizes diameter between 2 to 5mm. Free drainage system below the rainfall simulator is accompanied with outlet tanks attached with ultrasonic sensor devices to record the outflow data. During the experiments, the outflow received is 98% in average. Experiment results in typical runoff hydrograph and percolation rate of the MDPP system. This shows the ability of the rainfall simulator to obtain initial hydrology data to aid in the design of the MDPP prototype.
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Naves, Juan, Jose Anta, Joaquín Suárez i Jerónimo Puertas. "Development and Calibration of a New Dripper-Based Rainfall Simulator for Large-Scale Sediment Wash-Off Studies". Water 12, nr 1 (4.01.2020): 152. http://dx.doi.org/10.3390/w12010152.
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Rainfall simulators are useful tools for controlling the main variables that govern natural rainfall. In this study, a new drop-forming rainfall simulator, which consists of pressure-compensating dripper grids above a horizontal mesh that breaks and distributes raindrops, was developed to be applied in wash-off experiments in a large-scale physical model of 36 m2. The mesh typology and size, and its distance to drippers, were established through a calibration where rain uniformity and distributions of raindrop sizes and velocities were compared with local natural rainfall. Finally, the rain properties of the final solution were measured for the three rain intensities that the rainfall simulator is able to generate (30, 50 and 80 mm/h), obtaining almost uniform rainfalls with uniformity coefficients of 81%, 89% and 91%, respectively. This, together with the very suitable raindrop size distribution obtained, and the raindrop velocities of around 87.5% of the terminal velocity for the mean raindrop diameter, makes the proposed solution optimal for wash-off studies, where rain properties are key in the detachment of particles. In addition, the flexibility seen in controlling rain characteristics increases the value of the proposed design in that it is adaptable to a wide range of studies.
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Dey, Pankaj, i P. P. Mujumdar. "On the uniformity of rainfall distribution over India". Journal of Hydrology 578 (listopad 2019): 124017. http://dx.doi.org/10.1016/j.jhydrol.2019.124017.
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Kim, Haksoo, Teakjo Ko, Hyangseon Jeong i Sungje Ye. "The Development of a Methodology for Calibrating a Large-Scale Laboratory Rainfall Simulator". Atmosphere 9, nr 11 (2.11.2018): 427. http://dx.doi.org/10.3390/atmos9110427.
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The objective of this study was to establish a method to calibrate a large-scale laboratory rainfall simulator through developing and implementing an automated rainfall collection system to assess the reliability and accuracy of a rainfall simulator. The automated rainfall collection system was designed to overcome the limitations caused by the traditional manual measurement for obtaining the rainfall intensity and the spatial rainfall distribution in a large experimental area. The developed automated rainfall collection system was implemented to calibrate a large-scale laboratory rainfall simulator. The adequacy of average rainfall intensities automatically collected from the miniature tipping bucket rain gauges was assessed by comparison with those based on the volumetric method using the flowmeter. The functional relationships between the system variables of the rainfall simulator and the simulated intensity and uniformity distribution of rainfall (i.e., operation models) were derived based on a multiple regression approach incorporating correlation analysis on linear and logarithm scales, with consideration of a significance level. The operation models exhibited high accuracy with respect to both the rainfall intensity and the uniformity coefficients.
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Seong, Hoje, Dong Sop Rhee i Inhwan Park. "Analysis of Urban Flood Inundation Patterns According to Rainfall Intensity Using a Rainfall Simulator in the Sadang Area of South Korea". Applied Sciences 10, nr 3 (9.02.2020): 1158. http://dx.doi.org/10.3390/app10031158.
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An urban flood in the Sadang area located in South Korea was reproduced using a rainfall simulator. The rainfall simulator was developed to be able to demonstrate the rainfall intensity in range of 80–200 mm/h, and the artificial rainfall was created using 42 full cone type nozzles in the urban model. The uniformity coefficient of the rainfall distribution was 89.5%, which indicates the rainfall simulator achieved the high requirements for spatial uniformity. The flood experiments in the 1/200 scale model of the Sadang area were conducted using the rainfall simulator, and the flood patterns were investigated by changing the rainfall intensity. The rainwater mainly accumulated in the lowland of the crossroad where the entrances to the subway station are located. The flow velocity and the inundation depth were sharply increased until the rainfall intensity became 160 mm/h. Furthermore, the unstable human activities based on the moment and the friction instabilities also occurred from 160 mm/h. These results suggest that the study area requires flood damage mitigation facilities considering a rainfall intensity exceeding 160 mm/h.
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Si, Zhen Jiang, Yan Meng i Yan Huang. "Development of a Mobile Rainfall Simulator". Applied Mechanics and Materials 321-324 (czerwiec 2013): 118–22. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.118.
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in order to solve the rainfall simulator single control operation currently used in the experiment of soil erosion. A mobile rainfall simulator was designed. The device adopts a rainfall simulator and Longmen mobile support integration mode, which is controllable and mobile and easy to move. The results show that the equipment is advanced in technology, stable performance, flexible movement, rainfall uniformity high, effective rainfall area is 1.5×4.5m with rainfall intensity ranging from 9.5 to 100mm/h. and to a greater extent meets the needs of rainfall simulation. This rainfall simulator can be used in indoor and outdoor experiment of soil erosion in different slope, which improves the efficiency of utilization of rainfall simulator.
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Mendes, Thiago Augusto, Sávio Aparecido dos Santos Pereira, Juan Félix Rodriguez Rebolledo, Gilson de Farias Neves Gitirana, Maria Tereza da Silva Melo i Marta Pereira da Luz. "Development of a Rainfall and Runoff Simulator for Performing Hydrological and Geotechnical Tests". Sustainability 13, nr 6 (11.03.2021): 3060. http://dx.doi.org/10.3390/su13063060.
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Laboratory apparatuses for the analysis of infiltration and runoff enable studies under controlled environments and at reduced costs. Unfortunately, the design and construction of such systems are complex and face difficulties associated with the scale factor. This paper presents the design, construction, and evaluation of a portable rainfall and runoff simulator. The apparatus allows the evaluation of unsaturated soils with and without vegetation cover, under a wide range of simulation scenarios. The apparatus also enables the control of the intensity, size, and uniformity of simulated raindrops for variable surface slope, specimen thickness, and length conditions. The monitoring of the volumetric water content and matric suction and a rigorous computation of water balance are ensured. The obtained results indicate that the automated rainfall generator produces raindrops with Christiansen uniformity coefficients higher than 70%, and with an adequate distribution of raindrop sizes under a range of rainfall intensities between 86.0 and 220.0 mm h−1. The ideal rainfall generator conditions were established for a relatively small area equal to or lower than 1.0 m2 and considering rainfall events with return periods of 10 to 100 years.
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Lappas, I., I. Tsioumas i V. Zorapas. "Spatial-temporal analysis, variation and distribution of precipitation in the water district of Central-Eastern Greece". Bulletin of the Geological Society of Greece 47, nr 2 (24.01.2017): 740. http://dx.doi.org/10.12681/bgsg.11110.
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In this study, the spatial and temporal distribution of precipitation in the Water District of Central – Eastern Greece is investigated for the 42-year period (1968 – 2009) by using monthly mean data from 35 rainfall gauges, with adequate spatial coverage. The basic objective is to infer the pattern of spatial variation of rainfall over the study area based on meteorological observations. The accurate estimation of rainfall’s spatial distribution is needed whenever hydrological modelling is undertaken at the watershed scale for model calibration and validation. By using timeseries analysis and geostatistical methods, the regional and seasonal precipitation change and regime of this region during over 40 years is analyzed. However, this input is subject to uncertainty due to the random nature of rainfall. For all stations, uniformity checking and appropriate completion (where needed) took place and it appears that orography plays significant role as far the amount of rainfall is concerned. The results indicate that high variations in regional rainfall estimation occur in the mountainous areas, while the variance decreases in shadow areas in all seasons. The analysis of rainfall showed that there exists a wide variation in the rainfall amounts with variation from 382.4mm to 1397mm with a significantly decreasing trend.
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Liang, Rui, Qiao Zhu, Huan Lian Ren i Hua Jin. "Analysis on Characteristics of the Rainfall-Runoff in Beizhangdian Watershed". Applied Mechanics and Materials 90-93 (wrzesień 2011): 2578–82. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2578.
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Beizhangdian watershed is a typical semi-dry and semi-humid region, where human activities have little effect on the hydrological cycle. Based on a 30-year hydrological observation data, the precipitation, runoff, and rainfall-runoff relationship were researched by the hydrology statistics analysis methods. The results indicated that the inter-annual change of rainfall-runoff of the watershed is remarkable, the annual distribution of rainfall-runoff is extremely uneven, and rainfall-runoff mainly occurred in flood season (June ~ September). There is a good uniformity between the variation tendency of annual rainfall and annual runoff in time and amount, the correlation coefficient of rainfall and runoff is 0.74, the value of the F-test is 4.23.
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Liu, Bo, Xiaolei Wang, Lihua Shi, Xichuan Liu, Zhaojing Kang i Zhentao Chen. "Research on the Fine-Scale Spatial Uniformity of Natural Rainfall and Rainfall from a Rainfall Simulator with a Rotary Platform (RSRP)". Atmosphere 8, nr 12 (22.06.2017): 113. http://dx.doi.org/10.3390/atmos8070113.
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Isidoro, Jorge Manuel Guieiro Pereira, Alexandre Silveira i Bruno Oliveira Lima. "Development of a large-scale rainfall simulator for urban hydrology research". Engenharia Sanitaria e Ambiental 27, nr 1 (luty 2022): 169–73. http://dx.doi.org/10.1590/s1413-415220200365.
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ABSTRACT This work presented the development and testing of a large-scale rainfall simulator (LSRS) to be used as a research tool on rainfall-runoff and associated transport processes in urban areas. The rainfall simulator consists of a pressurized water supply system which supplies a set of 16 full-cone nozzles. Artificial rainfall with different rainfall intensities can be produced over an area of 100 m2 in a V shape. The assembly is housed in a tailor-made acrylic structure to eliminate the influence of wind and natural rainfall. Runoff is measured and collected at the outlet of the drainage basin, from where it is pumped to a storage tank that enables the reuse of water. Runoff hydrographs and pollutographs are presented as examples of possible outcomes from this facility. The LSRS is showed to be able to reproduce the rainfall-runoff and pollutant transport processes under simulated rainfall events with intensity and spatial uniformity similar to other experiments described in the literature.
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Man, Zihao, Qinghua Luan, Dan Xu, Congwu Sun i Yongzhen Niu. "The Design and Check of Regional Typical Rainfall Processes: A Case Study of Yongnian District, China". MATEC Web of Conferences 246 (2018): 01009. http://dx.doi.org/10.1051/matecconf/201824601009.
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Observing and analyzing runoff process is an important method to study the principle of runoff yield and concentration. However, natural rainfall is random and difficult to monitor the related runoff process timely, so most of the runoff processes analysis is based on the artificial rainfall experiments. In this study, the selected test site is located in Yongnian district, Hebei Province, China. Rainfall volume, rainfall peak, rainfall duration and peak ratio were considered as the key factors of designed rainfall type. Based on regional historical observed rainfall data from 1980 to 2012, the two mainly representative processes which was in flood season and non-flood season respectively, were calculated. The most typical rainfall process in each period was screened through two methods of characteristic frequency distribution. Furthermore, accuracy of rainfall intensity and uniformity of spatial and temporal distribution were selected as the criteria for correcting the artificial rainfall devices. This research is the foundation of the artificial runoff experiment and provide reference to regional climate change research and local water resources assessment.
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Santos, César Gabriel dos, Leonardo Nabaes Romano, Antonio Carlos Valdiero, Bruna Karine dos Santos i Gilmar Fernando Vogel. "The wetted area uniformity of the rainfall generated by different sprinkler nozzles". Brazilian Journal of Development 6, nr 6 (2020): 41689–702. http://dx.doi.org/10.34117/bjdv6n6-636.
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CHERAKU, SRIVALLI, P. SWATHI, Y. SUSHMITHA, D. PRANEETHA i CH RADHA SRIVALLI. "Fabrication and study of laboratory scale rainfall simulator for soil erosion assessment". Journal of AgriSearch 8, nr 2 (30.06.2021): 139–42. http://dx.doi.org/10.21921/jas.v8i2.7298.
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A rainfall simulator is an ideal tool for infiltration, soil erosion and other related research areas for replicating the process and characteristics of natural rainfall. The present paper describes the design of a comprehensive rainfall simulator. In this study a laboratory scale rainfall simulator is developed, which is particularly meant for the assessment of soil erosion at plot scale by considering various soil grain types, soil slope angles and surface exposures under different rainfall conditions. The Rainfall characteristics including the rainfall intensity and its spatial uniformity raindrop size and kinetic energy confirm that natural rainfall conditions are simulated with sufficient accuracy. The comparative measurement was carried out in a laboratory using rainfall simulator fabricated of 4 feet length and 2.5 feet width, where the applied slope angle is 3% with 39 mm/hr rainfall intensity. The runoff and soil loss for different samples were assessed by conducting number of trials. From the results it was found that the soil tilled and keeping it as a bare plot is more prone to runoff compared to soil without tilled and straw mulching has helped to reduce the runoff by 57% as compared to soil without mulching.
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Loch, R. J., B. G. Robotham, L. Zeller, N. Masterman, D. N. Orange, B. J. Bridge, G. Sheridan i J. J. Bourke. "A multi-purpose rainfall simulator for field infiltration and erosion studies". Soil Research 39, nr 3 (2001): 599. http://dx.doi.org/10.1071/sr00039.
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This paper describes a rainfall simulator developed for field and laboratory studies that gives great flexibility in plot size covered, that is highly portable and able to be used on steep slopes, and that is economical in its water use. The simulator uses Veejet 80100 nozzles mounted on a manifold, with the nozzles controlled to sweep to and from across a plot width of 1.5 m. Effective rainfall intensity is controlled by the frequency with which the nozzles sweep. Spatial uniformity of rainfall on the plots is high, with coefficients of variation (CV) on the body of the plot being 8–10%. Use of the simulator for erosion and infiltration measurements is discussed.
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Cai, Xin Ling, Qian Li, Lin Hu i Xiao Meng Zhao. "The Spatial and Temporal Variations Characteristic of Erosive Rainfall in the Yellow River Basin during 1961-2010". Advanced Materials Research 955-959 (czerwiec 2014): 3269–73. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.3269.
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Based on the daily rainfall data of 145 meteorological stations in the Yellow River basin, the spatial and temporal variations characteristic of erosive rainfall was analyzed by using statistical methods. The results show that the trend of the erosion precipitation, extreme precipitation and annual precipitation is significantly reduced. The erosion precipitation, extreme precipitation and annual precipitation are decrease from southeast to northwest. The long-term trends of different intensities rainfall is non-uniformity in space nearly 50 years. The erosion precipitation and annual precipitation are increasing in most areas of the upper reaches of the Yellow River basin, and are decreasing in the others areas, especially decreasing significantly in the water and soil loss of serious erosion in the Loess Plateau.
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Bosio, Roberto, Andrea Cagninei i Davide Poggi. "Large Laboratory Simulator of Natural Rainfall: From Drizzle to Storms". Water 15, nr 12 (12.06.2023): 2205. http://dx.doi.org/10.3390/w15122205.
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Rainfall simulators are versatile research tools that facilitate studying rain events and the many related physical phenomena. This work describes the development and validation of an indoor, large-scale rainfall simulator comprising a rain module installed 10.4 m from ground level, a redistribution screen at an adjustable distance below the rain module, and an ultra-filtered-water recirculation system. The droplet formers installed in the rain module were selected to achieve a wide range of rain intensities. The simulator was calibrated and validated using local natural rainfall data collected with a disdrometer over 30 months. The height of the rain module allows terminal velocity to be reached at ground level. At the same time, the redistribution screen and the droplet formers guarantee the wide variability of simulated rainfall in terms of intensity and the size of the drops. As a result, we show that the rain simulator, with proper calibration of the screen’s position, can reproduce measured natural rainfall over a broad range of intensities with high spatial and temporal uniformity and kinetic energy.
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Musa, John Jiya, Otuaro Ebierin Akpoebidimiyen, Pius Olusegun Olufemi Dada, Eze Peter Chukwu i Jamil dams-Suberu. "Physicochemical Analysis of Parameters Influencing Soil Loss for a Selected Location in North Central Nigeria Using Rainfall Simulator". Environment and Natural Resources Research 12, nr 2 (2.08.2022): 14. http://dx.doi.org/10.5539/enrr.v12n2p14.
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Developing a simple and proper model that can accurately predict runoff generation for various locations is in strong demand. This study developed a simple model based on the interactive effects of rainfall intensity and soil physicochemical properties on runoff using a locally produced rainfall simulator. The drop velocity (DV) was calculated to be 8.101m/s and 2.443 m/s when operated at maximum and minimum intensity, respectively, and the performance test revealed the experimental coefficient of uniformity (CU) and rainfall intensity from the simulator to be 79.86 % at 31.79 mmhr-1 and 78.03 % at 16.08 mmhr-1 at maximum and minimum intensity respectively. Results showed that the soils were loamy sand, with clay having the lowest percentage between 3.55% - 4% and sand having the highest percentage between 78.4% - 80.1% on both plots. Runoff significantly correlated with pH(H20), nitrogen and rainfall intensity for vegetative plot (p < 0.001, R2 = 86.29%) while for bare plot, runoff significantly correlated with pH (KCl), Electrical Conductivity, Exchangeable Calcium, and rainfall intensity (p < 0.001, R2 = 92.39%). This result revealed that rainfall intensity and alkalinity are key factors influencing runoff in the study location.
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Hirose, Masafumi, Riko Oki, Shuji Shimizu, Misako Kachi i Tomohiko Higashiuwatoko. "Finescale Diurnal Rainfall Statistics Refined from Eight Years of TRMM PR Data". Journal of Applied Meteorology and Climatology 47, nr 2 (1.02.2008): 544–61. http://dx.doi.org/10.1175/2007jamc1559.1.
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Abstract The adequacy of hourly rainfall sampling was examined in terms of the detection of diurnal variations using 8 yr (1998–2005) of data observed by the precipitation radar on the Tropical Rainfall Measuring Mission (TRMM) satellite. It was found that the monthly and hourly rain samples for each 0.2° grid point over the 8-yr period are composed of multiple precipitation systems. In this study, a “3-h-significant diurnal peak” was defined as the time of maximum rainfall with consecutive positive anomalies for more than 3 h. The fraction of the analyzed area with a 3-h-significant diurnal peak increased annually and accounted for 43% of the total global tropics at 0.2° resolution over the 8-yr period. The diurnal signature over Tibet and the Amazon showed a high degree of spatial uniformity (at >10° scale). The degree of similarity and locations of the regional diurnal characteristics are described in terms of seasonal variations and at multiple resolutions based on spatial uniformity. For example, uniform early-afternoon peaks generally appear over the coastal land and areas of high relief, whereas a seasonally invariant early-afternoon peak over the low-lying Amazon basin is recognized as a regional characteristic. In areas of coastal ocean, early-morning peaks appear in certain regions such as the area surrounding the so-called Maritime Continent and the area off the west coast of Mexico. These peaks are distinct from the global characteristics of late-morning rainfall maxima recorded over most coastal oceans and early-morning peaks recorded over open ocean. The results are also compared with those derived from TRMM Microwave Imager (TMI) data. In addition to obtaining a coherent signal, regional differences in the timing of maximum rainfall over the Tibetan Plateau were addressed; this discrepancy is attributed to limitations of the scattering algorithm used for TMI data in terms of detecting shallow convection and screening cold surfaces.
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Hirose, M., i K. Okada. "A 0.01° Resolving TRMM PR Precipitation Climatology". Journal of Applied Meteorology and Climatology 57, nr 8 (sierpień 2018): 1645–61. http://dx.doi.org/10.1175/jamc-d-17-0280.1.
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AbstractIn this study, rainfall data are prepared at a 0.01° scale using 16-yr spaceborne radar data over the area of 36.13°S–36.13°N as provided by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). A spatial resolution that is finer than the field of view is obtained by assuming rainfall uniformity within an instantaneous footprint centered on the PR footprint geolocation. These ultra-high-resolution data reveal local rainfall concentrations over slope areas. A new estimate of the maximum rainfall at Cherrapunji, India, was observed on the valley side, approximately 5 km east of the gauge station, and is approximately 50% higher than the value indicated by the 0.1°-scale data. A case study of Yakushima Island, Japan, indicates that several percent of the sampling error arising from the spatial mismatch may be contained in conventional 0.05°-scale datasets generated without footprint areal information. The differences attributable to the enhancement in the resolution are significant in complex terrain such as the Himalayas. The differences in rainfall averaged for the 0.1° and 0.01° scales exceed 10 mm day−1 over specific slope areas. In the case of New Guinea, the mean rainfall on a mountain ridge can be 30 times smaller than that on an adjacent slope at a distance of 0.25°; this is not well represented by other high-resolution datasets based on gauges and infrared radiometers. The substantial nonuniformity of rainfall climatology highlights the need for a better understanding of kilometer-scale geographic constraints on rainfall and retrieval approaches.
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Chow, T. L., i H. W. Rees. "Effects of potato hilling on water runoff and soil erosion under simulated rainfall". Canadian Journal of Soil Science 74, nr 4 (1.11.1994): 453–60. http://dx.doi.org/10.4141/cjss94-059.
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The practice of planting potatoes (Solanum tuberosum) in rows and hilling the plants at some stage of growth has been universally adopted. Using a rainfall simulator and runoff-erosion plots (0.9 m wide × 1 m long), the effects of hilling on runoff, infiltration, and soil loss were examined on an Orthic Dystric Brunisol. Tests of the rainfall simulator revealed that variations in operating pressure (36.5–62.1 kPa) and soil slope conditions (0–15%) did not significantly (P < 0.05) affect the intensity and spatial uniformity of the simulated rainfall. The potato hills studied were 90 cm apart with heights of approximately 25 cm, row-sideslopes of 35° and furrow widths of 10 cm, which are similar to those used in commercial production. Although not significantly different at P < 0.05, the runoff rate from the hilled plots was approximately 20% higher than that from the unhilled plots. Hilling resulted in a significant reduction in infiltration rate (P < 0.05). Average soil loss from the hilled plots was approximately four times higher than from the unhilled plots. For runoff rates below a critical value of 0.93 L min−1, the rate of soil loss correlated linearly with the runoff rate, whereas a non-linear exponential equation was generated for the entire range of runoff with r = 0.94. The increase in soil loss as a result of hilling was adequately predicted from row-sideslope gradients using an existing equation derived from erosion data obtained from fields having conditions similar to that of potato hills. Key words: Universal soil loss equation, slope steepness, cover and management factor, row-sideslope, spatial uniformity, infiltration
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Liu, Yan, Xia Wang, Sanyi Tang i Robert A. Cheke. "The relative importance of key meteorological factors affecting numbers of mosquito vectors of dengue fever". PLOS Neglected Tropical Diseases 17, nr 4 (13.04.2023): e0011247. http://dx.doi.org/10.1371/journal.pntd.0011247.
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Although single factors such as rainfall are known to affect the population dynamics of Aedes albopictus, the main vector of dengue fever in Eurasia, the synergistic effects of different meteorological factors are not fully understood. To address this topic, we used meteorological data and mosquito-vector association data including Breteau and ovitrap indices in key areas of dengue outbreaks in Guangdong Province, China, to formulate a five-stage mathematical model for Aedes albopictus population dynamics by integrating multiple meteorological factors. Unknown parameters were estimated using a genetic algorithm, and the results were analyzed by k-Shape clustering, random forest and grey correlation analysis. In addition, the population density of mosquitoes in 2022 was predicted and used for evaluating the effectiveness of the model. We found that there is spatiotemporal heterogeneity in the effects of temperature and rainfall and their distribution characteristics on the diapause period, the numbers of peaks in mosquito densities in summer and the annual total numbers of adult mosquitoes. Moreover, we identified the key meteorological indicators of the mosquito quantity at each stage and that rainfall (seasonal rainfall and annual total rainfall) was more important than the temperature distribution (seasonal average temperature and temperature index) and the uniformity of rainfall annual distribution (coefficient of variation) for most of the areas studied. The peak rainfall during the summer is the best indicator of mosquito population development. The results provide important theoretical support for the future design of mosquito vector control strategies and early warnings of mosquito-borne diseases.
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Ricks, Matthew D., Matthew A. Horne, Brian Faulkner, Wesley C. Zech, Xing Fang, Wesley N. Donald i Michael A. Perez. "Design of a Pressurized Rainfall Simulator for Evaluating Performance of Erosion Control Practices". Water 11, nr 11 (14.11.2019): 2386. http://dx.doi.org/10.3390/w11112386.
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Construction site erosion and resulting sedimentation constitutes one of the greatest non-point source pollution threats to our nation’s waterways. Erosion control practices are important aspects of any construction project due to their ability to limit the process of erosion. Testing erosion control practices under simulated rainfall representative of conditions experienced on construction sites is important to better understand their erosion reduction capabilities. Full-scale testing using simulated rainfall has been shown to provide controllable and repeatable results, in comparison to field-testing under natural conditions. Therefore, the focus of this study was to design, construct, and calibrate a pressurized rainfall simulator testing apparatus capable of accurately and repeatedly simulating rainfall intensities of 50.8, 101.6, and 152.4 mm/hr (2.0, 4.0, and 6.0 in/hr) for 20-min intervals. The developed testing apparatus consisted of a 12 m (40 ft) long by 2.4 m (8.0 ft) earthen slope at a 3H:1V slope. Ten sprinkler risers at a height of 4.27 m (14 ft) were installed around the perimeter of the slope to create a uniform distribution of rainfall. Data collection procedures consisted of collecting and analyzing rainfall depth, drop size distributions, and sediment concentrations. The optimum location for each sprinkler riser, as well as the most accurate nozzle configuration, were determined through test procedures developed for this study. Through calibration testing, the simulator was found to produce accurate rainfall intensities with relative errors of 1.17–4.00% of the target intensities. Uniformity of rainfall distribution ranged from 85.7 to 87.5%. Average drop sizes were determined to be between 2.35 and 2.58 mm (0.093 to 0.102 in.).
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Wilson, T. G., C. Cortis, N. Montaldo i J. D. Albertson. "Development and testing of a large, transportable rainfall simulator for plot-scale runoff and parameter estimation". Hydrology and Earth System Sciences 18, nr 10 (22.10.2014): 4169–83. http://dx.doi.org/10.5194/hess-18-4169-2014.
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Abstract. There is increased interest in the interplay between vegetation conditions and overland flow generation. The literature is unclear on this relationship, and there is little quantitative guidance for modeling efforts. Therefore, experimental efforts are needed, and these call for a lightweight transportable plot-scale (>10 m2) rainfall simulator that can be deployed quickly and quickly redeployed over various vegetation cover conditions. Accordingly, a variable-intensity rainfall simulator and collection system was designed and tested in the laboratory and in the field. The system was tested with three configurations of common pressure washing nozzles producing rainfall intensities of 62, 43, and 32 mm h-1 with uniformity coefficients of 76, 65, and 62%, respectively, over a plot of 15.12 m2. Field tests were carried out on a grassy field with silt–loam soil in Orroli, Sardinia, in July and August 2010, and rainfall, soil moisture, and runoff data were collected. The two-term Philip infiltration model was used to find optimal values for the saturated hydraulic conductivity of the soil surface and bulk soil, soil water retention curve slope, and air entry suction head. Optimized hydraulic conductivity values were similar to both the measured final infiltration rate and literature values for saturated hydraulic conductivity. This inexpensive (less than USD 1000) rainfall simulator can therefore be used to identify field parameters needed for hydrologic modeling.
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Wilson, T. G., C. Cortis, N. Montaldo i J. D. Albertson. "Development and testing of a large, transportable rainfall simulator for plot-scale runoff and parameter estimation". Hydrology and Earth System Sciences Discussions 11, nr 4 (17.04.2014): 4267–310. http://dx.doi.org/10.5194/hessd-11-4267-2014.
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Abstract. There is increased interest in the interplay between vegetation conditions and overland flow generation. The literature is unclear on this relationship and there is little quantitative guidance for modeling efforts. Therefore, experimental efforts are needed and these call for a lightweight transportable plot-scale (>10 m2) rainfall simulator that can be deployed quickly and quickly redeployed over various vegetation cover conditions. Accordingly, a variable intensity rainfall simulator and collection system was designed and tested in the laboratory and in the field. The system was tested with three configurations of common pressure washing nozzles producing rainfall intensities of 62, 43, and 32 mm h−1 with uniformity coefficients of 76, 65, and 62, respectively, over a plot of 15.12 m2. Field tests were carried out in on a grassy field with silt-loam soil in Orroli, Sardinia in July and August 2010, and rainfall, soil moisture, and runoff data were collected. The two-term Philip infiltration model was used to find optimal values for the saturated hydraulic conductivity of the soil surface and bulk soil, soil water retention curve slope, and air entry suction head. Optimized hydraulic conductivity values were comparable to both the measured final infiltration rate and literature values for saturated hydraulic conductivity. This inexpensive rainfall simulator can therefore be used to identify field parameters needed for hydrologic modeling.
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Alfieri, Lorenzo, Pierluigi Claps, Paolo D’Odorico, Francesco Laio i Thomas M. Over. "An Analysis of the Soil Moisture Feedback on Convective and Stratiform Precipitation". Journal of Hydrometeorology 9, nr 2 (1.04.2008): 280–91. http://dx.doi.org/10.1175/2007jhm863.1.
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Abstract Land–atmosphere interactions in midlatitude continental regions are particularly active during the warm season. It is still unclear whether and under what circumstances these interactions may involve positive or negative feedbacks between soil moisture conditions and rainfall occurrence. Assessing such feedbacks is crucially important to a better understanding of the role of land surface conditions on the regional dynamics of the water cycle. This work investigates the relationship between soil moisture and subsequent precipitation at the daily time scale in a midlatitude continental region. Sounding data from 16 locations across the midwestern United States are used to calculate two indices of atmospheric instability—namely, the convective available potential energy (CAPE) and the convective inhibition (CIN). These indices are used to classify rainfall as convective or stratiform. Correlation analyses and uniformity tests are then carried out separately for these two rainfall categories, to assess the dependence of rainfall occurrence on antecedent soil moisture conditions, using simulated soil moisture values. The analysis suggests that most of the positive correlation observed between soil moisture and subsequent precipitation is due to the autocorrelation of long stratiform events. The authors found both areas with positive and areas with negative feedback on convective precipitation. This behavior is likely due to the contrasting effects of soil moisture conditions on convective phenomena through changes in surface temperature and the supply of water vapor to the overlying air column. No significant correlation is found between daily rainfall intensity and antecedent simulated soil moisture conditions either for convective or stratiform rainfall.
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Kolathayar, Sreevalsa, T. G. Sitharam i Shuqing Yang. "Coastal reservoir strategy to enhance India's freshwater storage by impounding river flood waters: a detailed overview". Water Supply 19, nr 3 (6.08.2018): 703–17. http://dx.doi.org/10.2166/ws.2018.140.
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Abstract This paper revisits the water resource scenario in India and presents the adequacy of the coastal reservoir concept to address water scarcity by impounding excess river flood waters. Although there has been no significant change in India's rainfall pattern in the last 100 years, there is a spatial non-uniformity in the rainfall events that occur which makes it difficult to pre-plan large-scale water storage at different locations. This study highlights the fact that there is enough water available but the deficiency is in storage. A large portion of freshwater from river systems, groundwater and wetlands drains into the sea due to insufficient storage facilities. Coastal reservoirs enable the storage of excess river flood waters near the coast for future use. This paper discusses current water supply solutions available in the country, and the efficacy of coastal reservoirs along with feasibility implications. The associated rewards and challenges are also discussed. The paper presents details of existing coastal reservoirs worldwide and recent feasibility studies envisaging coastal reservoirs in India.
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Wurr, D. C. E., i Jane R. Fellows. "The influence of sowing depth and seed press wheel weighting on seedling emergence of crisp lettuce". Journal of Agricultural Science 104, nr 3 (czerwiec 1985): 631–36. http://dx.doi.org/10.1017/s0021859600044415.
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SummaryThe effects on emergence and growth of crisp lettuce seedlings as a result of sowing seeds at different depths and pressing them into the furrow bottom with a weighted seed press wheel were examined in three similar experiments in 1982, 1983 and 1984. Sowing depth had a considerable effect on percentage seedling emergence and the spread of emergence times but the pattern of response varied from year to year and appeared to be related to differences in soil moisture content. The most uniform emergence and the highest level of emergence were achieved by sowing shallowly (< 10 mm) with rainfall almost immediately after sowing then keeping the soil moisture content close to field capacity for 2 days. When rainfall or irrigation were delayed, drilling 15–20 mm deep gave more consistent results. Effects on seedling weight and variability of weight were associated with the time and uniformity of seedling emergence. Later emerging seedlings were lighter and a wide spread of emergence times gave seedlings of variable weight. There was virtually no effect on emergence of using additional weights on a seed press wheel.
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White, C. B., P. R. Houser, A. M. Arain, Z. L. Yang, K. Syed i W. J. Shuttleworth. "The aggregate description of semi-arid vegetation with precipitation-generated soil moisture heterogeneity". Hydrology and Earth System Sciences 1, nr 1 (31.03.1997): 205–12. http://dx.doi.org/10.5194/hess-1-205-1997.
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Abstract. Meteorological measurements in the Walnut Gulch catchment in Arizona were used to synthesize a distributed, hourly-average time series of data across a 26.9 by 12.5 km area with a grid resolution of 480 m for a continuous 18-month period which included two seasons of monsoonal rainfall. Coupled surface-atmosphere model runs established the acceptability (for modelling purposes) of assuming uniformity in all meteorological variables other than rainfall. Rainfall was interpolated onto the grid from an array of 82 recording rain gauges. These meteorological data were used as forcing variables for an equivalent array of stand-alone Biosphere-Atmosphere Transfer Scheme (BATS) models to describe the evolution of soil moisture and surface energy fluxes in response to the prevalent, heterogeneous pattern of convective precipitation. The calculated area-average behaviour was compared with that given by a single aggregate BATS simulation forced with area-average meteorological data. Heterogeneous rainfall gives rise to significant but partly compensating differences in the transpiration and the intercepted rainfall components of total evaporation during rain storms. However, the calculated area-average surface energy fluxes given by the two simulations in rain-free conditions with strong heterogeneity in soil moisture were always close to identical, a result which is independent of whether default or site-specific vegetation and soil parameters were used. Because the spatial variability in soil moisture throughout the catchment has the same order of magnitude as the amount of rain falling in a typical convective storm (commonly 10% of the vegetation's root zone saturation) in a semi-arid environment, non-linearity in the relationship between transpiration and the soil moisture available to the vegetation has limited influence on area-average surface fluxes.
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Vidyarthi, Vikas Kumar, i Ashu Jain. "Incorporating non-uniformity and non-linearity of hydrologic and catchment characteristics in rainfall–runoff modeling using conceptual, data-driven, and hybrid techniques". Journal of Hydroinformatics 24, nr 2 (3.02.2022): 350–66. http://dx.doi.org/10.2166/hydro.2022.088.
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Abstract The rainfall–runoff (RR) process in a catchment is non-uniform, complex, dynamic, and non-linear in nature. Although a number of advanced conceptual and data-driven techniques have been proposed in the past, the accurate estimation of daily runoff still remains a challenging task. A majority of conceptual models proposed so far suffer from the assumptions of linearity during their modeling. In this paper, novel hybrid approaches are proposed that are capable of exploiting the strength of both conceptual and data-driven techniques in RR modeling. A conceptual technique is first used to generate sub-basins’ runoff hydrographs in upstream reaches and then data-driven techniques are employed for routing them to the outlet of the catchment. The hybrid models’ performances are compared with standalone conceptual and data-driven models by employing the daily rainfall, runoff, and temperature data derived from the Kentucky River basin, USA. The results show that the proposed hybrid models, which do not assume the RR process to be a linear process to simulate the flow, outperform their individual counterparts. It is concluded that in order to achieve improved accuracy in RR modeling, the real-life process needs to be represented as accurately as possible in the modeling effort rather than making simplified assumptions.
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Kavian, Ataollah, Iman Saleh, Mahmoud Habibnejad i Zeinab Jafarian. "Application of Vegetative Buffer Strips Under Natural Rainfall to Conserve Soil and Water". Agriculture (Pol'nohospodárstvo) 64, nr 1 (1.04.2018): 17–27. http://dx.doi.org/10.2478/agri-2018-0002.
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Abstract Soil erosion is one of the most serious environmental issues in the world. The use of vegetative buffer strips is an effective strategy to reduce surface water pollutions as well as soil erosion. The present research has been conducted with aim to study the efficiency of buffer strips in runoff volume and sediment control using experimental plots. In this regard, twelve experimental plots with the dimensions of 1 m × 10 m were provided, and runoff samples were collected monthly to measure runoff volume and sediment. Vetiver grass and tall fescue were used as the plant species of the studied vegetative buffer strips. It was found that, vegetative buffer strips reduced the runoff volume up to 97% and sediment concentration up to 96%. Vetiver grass showed a high efficiency in runoff and sediment control; but, the maximum efficiency is achieved when this species is used along with a plant similar to the tall fescue in terms of density and uniformity. Also, periodic cutting the plants and cleaning the buffer strips can be considered as effective strategies to prevent vegetative buffer strips acting as the source of sediment.
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Stanley, C. D., G. A. Clark, E. E. Albregts i F. S. Zazueta. "USE OF FIELD-LOCATED DRAINAGE LYSIMETERS FOR THE DETERMINATION OF STRAWBERRY WATER REQUIREMENTS". HortScience 25, nr 9 (wrzesień 1990): 1097d—1097. http://dx.doi.org/10.21273/hortsci.25.9.1097d.
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Sixteen field-located drainage lysimeters (each 60 cm wide, 2.44 m long, 60 cm deep) designed specifically for determination of water requirements for fruiting strawberry production (season - Oct to April) were installed in 1986. Each lysimeter was equipped with individual micro-irrigation and drainage collection systems automated for minimal management input. Initially, computer control (using a low-cost microcomputer) was used to continuously check switching-tensiometers located in each lysimeter and apply irrigation water as needed, A drainage suction (-10 MPa) was applied continuously to simulate field drainage conditions. Manually-installed lysimeter covers were used to protect the plots from interference from rainfall when needed, Initial irrigation application treatments were set at four levels of soil moisture tension controlled by tensiometers and were measured using flow meters for each lysimeter. This paper will discuss problems that were experienced with the initial setup (difficulty in measuring actual application amounts, tensiometer and computer control, elimination of rainfall interference, uniformity of irrigation application, and salinity in the rooting zone) and the modifications (pressurized reservoir tanks, construction of motorized rain-out shelter, micro-irrigation emitters used, and fertilization program) which have been made to overcome them,
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SILVA, LÍVIA MARIA CAVALCANTE, FABIANO SIMPLICIO BEZERRA, MARIA CATIANA DE VASCONCELOS, MADSON RAFAEL BARBALHO DA SILVA, ANA CLÁUDIA DAVINO DOS SANTOS i CERES DUARTE GUEDESCABRAL DE ALMEIDA. "GAP FILLING PROCEDURES OF CLIMATOLOGICAL SERIES IN THE STATE OF PERNAMBUCO". IRRIGA 1, nr 4 (23.12.2021): 754–64. http://dx.doi.org/10.15809/irriga.2021v1n4p754-764.
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This study aimed to compare the applicability of three methods of filling gaps in rainfall and temperature data from thirteen automatic weather stations (AWS) in the state of Pernambuco, from January to December 2019. The methods used were arithmetic mean, regional weighting, and simple linear regression. The data estimated by filling techniques have been subjected to comparison using R² and descriptive statistical analysis. The estimated data of air temperature presented R2 equal or very close to 1 for the three methods. On the other hand, the estimated data of rainfall showed values similar or closer to the real data only to regional weighting (R² = 1) and linear regression (R² = 0.99) methods. The smallest values of standard deviation (1.70) for temperature were obtained with linear regression. The regional weighting method and unfilled data showed greater uniformity for precipitation. The analyzed methods to estimate the climatic variables, air temperature, and precipitation, on a monthly scale, were efficient to fill in missing data in the evaluated AWS. The simple linear regression method is more efficient and adequate, followed by regional weighting, to fill in missing data in climate databases.
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Zhao, Si-yuan, Yang-wen Jia, Jia-guo Gong, Cun-wen Niu, Hui-dong Su, Yong-de Gan i Huan Liu. "Spatial Variability of Preferential Flow and Infiltration Redistribution along a Rocky-Mountain Hillslope, Northern China". Water 12, nr 4 (13.04.2020): 1102. http://dx.doi.org/10.3390/w12041102.
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Rock fragments in soil strongly increase the complexity of hydrological processes. Spatial variability of preferential flow and infiltration characteristics, especially along a rocky-mountain hillslope are poorly understood. In this study, five rainfall–dye tracer experiments were performed in the rocky Taihang Mountains, northern China, to investigate the spatial variability of preferential flow and infiltration redistribution on different hillslope positions. Tracers were used to distinguish macropore flow and actual water flow patterns, and preferential flow indices and spatial non–uniformity of the infiltration redistribution were calculated using image analysis. Results showed increasing trends in the dye coverage, maximum infiltration depth, and steady infiltration rate with increased hillslope position, with a preferential flow fraction of 0.10, 0.11, 0.15, 0.29, and 0.26 for the bottom–, down–, mid–, upper–, and top–slope positions, respectively. With increased hillslope position, the spatial non–uniformity of the infiltration redistribution gradually increased in orthogonal and parallel directions to the stained section, and was supported by the fractal dimensions. Positive (gravel mass ratio, saturated water content, altitude, hydraulic conductivity and roots) and negative (bulk density and clay content) impacts on preferential flow and infiltration redistribution were quantitatively emphasized. The characteristic and mechanism of infiltration process were further identified along a rocky-mountain hillslope.
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van der Burgt, Xander M. "Determination of the Age of Pinus Occidentalis in La Celestina, Dominican Republic, by the Use of Growth Rings". IAWA Journal 18, nr 2 (1997): 139–46. http://dx.doi.org/10.1163/22941932-90001475.
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The growth rings of Pinus occidentalis Swartz trees in La Celestina, Dominican Republic, show between-tree uniformity. With difficulty, two mean time series were made from ring widths of 1) all visible, including intra-annual, rings and 2) groups of rings that were hypothesized to be annual. Both were compared with a 63-year range of rainfall data. An annual periodicity in wood formation is present, but obscured by many intra-annual rings. The annual periodicity of the trees may be a remnant of their possible origin from higher altitudes, where frosts may occur during the cold season. The youngest of the 7 investigated trees was about 39 years old; the oldest about 46 years. These seven trees contain between approximately 2 and 6 growth rings per year, with an average of about 3.5-4.
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Bradford, R. B., R. Ragab, S. M. Crooks, F. Bouraoui i E. Peters. "Simplicity versus complexity in modelling groundwater recharge in Chalk catchments". Hydrology and Earth System Sciences 6, nr 5 (31.10.2002): 927–37. http://dx.doi.org/10.5194/hess-6-927-2002.
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Abstract. Models of varying complexity are available to provide estimates of recharge in headwater Chalk catchments. Some measure of how estimates vary between different models can help guide the choice of model for a particular application. This paper compares recharge estimates derived from four models employing input data at varying spatial resolutions for a Chalk headwater catchment (River Pang, UK) over a four-year period (1992-1995) that includes a range of climatic conditions. One model was validated against river flow data to provide a measure of their relative performance. Each model gave similar total recharge for the crucial winter recharge period when evaporation is low. However, the simple models produced relatively lower estimates of the summer and early autumn recharge due to the way in which processes governing recharge especially evaporation and infiltration are represented. The relative uniformity of land use, soil types and rainfall across headwater, drift-free Chalk catchments suggests that complex, distributed models offer limited benefits for recharge estimates at the catchment scale compared to simple models. Nonetheless, distributed models would be justified for studies where the pattern and amount of recharge need to be known in greater detail and to provide more reliable estimates of recharge during years with low rainfall. Keywords: Chalk, modelling, groundwater recharge
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Fenner, William, Rivanildo Dallacort, Paulo S. L. de Freitas, Cleonir A. Faria Júnior, Marco A. C. de Carvalho i Guilherme Bariviera. "Dual crop coefficient of common bean in Tangará da Serra, Mato Grosso". Revista Brasileira de Engenharia Agrícola e Ambiental 20, nr 5 (maj 2016): 455–60. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n5p455-460.
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ABSTRACT This study aimed to determine the dual crop coefficient of common bean ( Phaseolus vulgaris L.) for Tangará da Serra-MT, Brazil. The study used the FAO-56 dual kc method, dividing the kc into soil evaporation coefficient (ke), determined in microlysimeters, and basal crop coefficient (kcb), determined in weighing lysimeters. The study was conducted from July 10 (sowing) to October 6, 2014 (harvest), using the common bean cultivar 'BRS Estilo' and a sprinkler irrigation system with a coefficient of uniformity greater than 80%. The total rainfall and irrigation during the crop cycle (84 days) was 524.8 mm; the potential evapotranspiration (ETo) estimated for the period was 327.9 mm, whereas the crop evapotranspiration (ETc) accumulated during the cycle, determined in lysimeters, was equal to 477.5 mm. The kcb values determined for the initial, full development and final stages were 0.32, 1.10 and 0.81, respectively, while for ke, the respective values were 0.85, 0.40 and 0.53.
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Baxendale, F. P., R. C. Shearman i L. A. Wit. "Annual White Grub Control in Kentucky Bluegrass, 1987". Insecticide and Acaricide Tests 13, nr 1 (1.01.1988): 330a. http://dx.doi.org/10.1093/iat/13.1.330a.
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Abstract Nine insecticides were applied to 5- × 10-ft plots on a golf course in Lincoln, Nebr. (Lancaster County), on 5 Aug. Granular formulations were combined with 13.5 oz Milorganite, which served as a carrier, and were hand shaken over plots. Liquid formulations were applied with a C02 sprayer using an LF-4 nozzle at 28 psi and a spray rate of 4 gal/1000 sq ft spray rate. To ensure uniformity among plots, 13.5 oz of Milorganite were also applied over plots receiving liquid formulations and over untreated checks. The experiment was replicated 4 times using a randomized complete block design. Immediately following insecticide applications, the test area was irrigated with approximately 0.75 inches of water. An additional 3.75 inches of rainfall occurred during the posttreatment period. Product efficacy was evaluated 14 days after application (19 Aug) by removing 2 sections of sod, 1-sq-ft × 4 inches deep, from each plot and counting the number of surviving grubs.
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Baxendale, F. P., R. C. Shearman i L. A. Wit. "Control of Annual White Grubs in Kentucky Bluegrass, 1987". Insecticide and Acaricide Tests 13, nr 1 (1.01.1988): 331. http://dx.doi.org/10.1093/iat/13.1.331.
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Abstract Seven insecticides were applied to 3- × 6-ft plots in a lawn in Lincoln, Nebr. (Lancaster County), on 10 Jul. Granular formulations were combined with 4.8 oz Milorganite, which served as a carrier, and were hand shaken over plots. Liquid formulations were applied with a C02 sprayer using a LF-4 nozzle at 28 psi and a spray rate of 4 gal/1000 sq ft. To ensure uniformity among plots, 4.8 oz of Milorganite also was applied to plots receiving liquid formulations and over untreated checks. The experiment was replicated 4 times using a randomized complete block design. Immediately following insecticide applications, the test area was irrigated with approximately 0.5 inches of water. An additional 1.0 inch of water was applied during the next 2 wk. No rainfall occurred during the posttreatment period. Product efficacy was evaluated 14 days after application (24 Jul) by removing 2 sections of sod, 1-sq-ft × 4 inches deep, from each plot and counting the number of surviving grubs.
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Henshall, W. R., R. M. Beresford, R. W. Chynoweth i P. Ramankutty. "Comparing surface wetness inside and outside grape canopies for regionwide assessment of plant disease risk". New Zealand Plant Protection 58 (1.08.2005): 80–83. http://dx.doi.org/10.30843/nzpp.2005.58.4258.
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Wetness duration measured by flat plate sensors inside and outside a grape canopy was recorded from DecemberMarch Sensors outside the canopy generally recorded longer wetness duration than sensors inside the canopy For days with rain short wetness durations detected by outside sensors were not detected by inside sensors because of sheltering by the canopy When wetness arose solely from dew duration inside was much shorter than outside for prolonged wet periods Wetness was used to calculate infection periods according to two botrytis bunch rot risk models Agreement between sensors was worse inside the canopy than outside although on occasions when rainfall exceeded 10 mm there was greater uniformity between sensors For regionwide disease risk monitoring wetness duration measured outside leaf canopies at standard meteorological sites would give a worstcase estimate of disease risk Regression equations are presented that allow estimation of inside wetness duration from outside wetness duration for rainy and nonrainy days
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Bischokov, Ruslan M. "Fuzzy logic device for crop analysing, modeling and forecasting in the Kabardino-Balkarian Republic". RUDN Journal of Agronomy and Animal Industries 15, nr 2 (15.12.2020): 123–33. http://dx.doi.org/10.22363/2312-797x-2020-15-2-123-133.
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Using computer fuzzy-logical models based on empirical values of climatic characteristics (rainfall, temperature and humidity) of long-term observations (1955-2018) from meteorological stations in the Kabardino-Balkarian Republic (Nalchik, Baksan, Prokhladny and Terek) and crop yields (winter wheat, spring wheat, corn, sunflower, millet, oats), dependence of crop yields on variations of climatic factors were analyzed and a specific forecast was given. Setting expected values of climatic characteristics in computer model, we received possible values of productivity for the next season. Uniformity assessment (Dixon and Smirnov - Grabbsas criterion), stability (Student and Fischers criterion), statistical importance of parameters of distribution and accidental errors were determined. Originality of the method is in the fact that in the form of input parameters of the model predictors, the previously calculated forecast values of the meteorological parameters for the next agricultural year were used, and at the output, the predicted values of crop productivity were obtained as predictants. Furthermore, recommendations on adoption of management decisions were developed.
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Bilibio, Carolina, Christian Schellert, Daniel Uteau, Stephan Peth i Oliver Hensel. "Comparison of an Innovative Mobile Strip Irrigation System with Full-Area Sprinkler Watering". Journal of the ASABE 65, nr 6 (2022): 1365–73. http://dx.doi.org/10.13031/ja.15204.
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HighlightsInnovative stripwise irrigation directs water only to ridge crests, not furrows.Mobile strip irrigation saved 51% of the carrot water requirements.The uniformity coefficient of the irrigation above the ridges was high.No significant differences in the carrot yield were verified between the irrigation systems.The water use efficiency was higher for the mobile strip irrigation system.ABSTRACT. Irrigation plays an important role in agriculture in temperate regions because of the reduction in rainfall frequency during the spring and summer months along with the increase in average temperature and evapotranspiration. To increase irrigation efficiency, we developed an innovative mobile strip irrigation system for ridge culture. The objective of this pilot study was to compare the new technology with a standard full-area sprinkler system and analyze the yield, flow rate, applied irrigation on the ridges, and variability of the irrigation depths expressed by the Christiansen uniformity coefficient (CUC) and distribution uniformity coefficient (CUD). The experimental design applied the two treatments to carrots grown on eight ridges covering an area of 210 m2. The experiment was conducted at the University of Kassel, Witzenhausen, Germany. The results showed a flow rate ranging from 54.7 to 72.7 l h–1. Good CUC (89%) and excellent CUD (82%) were obtained for the mobile irrigation system, indicating low variability of irrigation depths. The water content in the ridge crest increased to field capacity after irrigation, with a moderate coefficient of variation (14%) among the measurements. In addition, water use reduction with respect to the standard irrigation system of 51% during the treatments, or 29% considering the entire experiment time, was observed, and no significant differences in the total fresh yield between the irrigation systems were verified. Because only a single sprinkler irrigation system with an irrigation efficiency of 80% was used, care must be taken when extrapolating the findings of the present study. High irrigation efficiency sprinkler irrigation systems with multiple sprinklers, which reduce the sprinkler irrigation amount, can be considered in future studies to confirm the increased water usage efficiency of the mobile strip irrigation system. Keywords: Carrots cultivation, Irrigation, Ridge agriculture, Water content, Water distribution, Water saving.
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Mantovani, Everardo C., Gregório G. Faccioli, Brauliro Gonçalves Leal, Antonio Alves Soares, Luis Claudio Costa i Paulo Sergio L. Freitas. "INFLUENCE OF THE WATER DISTRIBUTION UNIFORMITY AND IRRIGATION DEPTH ON THE YIELD OF IRRIGATED BEAN CROP". IRRIGA 14, nr 4 (18.12.2009): 458–69. http://dx.doi.org/10.15809/irriga.2009v14n4p458-469.
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INFLUENCE OF THE WATER DISTRIBUTION UNIFORMITY AND IRRIGATION DEPTH ON THE YIELD OF IRRIGATED BEAN CROP Everardo C. Mantovani1; Gregório G. Faccioli2; Brauliro Gonçalves Leal3;Antônio Alves Soares1; Luis Cláudio Costa1; Paulo Sérgio L. Freitas4 1Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, MG everardo@ufv.br2Núcleo de Estudos e Pesquisas do Nordeste, Universidade Federal de Sergipe, São Cristovão, SE3Intec Consultoria e Assessoria Ltda, Viçosa, MG4Departamento de Agronomia, Universidade Estadual de Maringá, Maringá, PR 1 ABSCTRACT This study aimed to evaluate the influence of the water distribution uniformity and three irrigation depths on the production variables for the bean crop, using a conventional sprinkler irrigation system, during the winter season. The treatments consisted of three irrigation depths and two uniformity levels of water distribution represented by the Christiansen uniformity coefficient (CUC). In the treatments L1A and L1B a sufficient water depth was applied to raise the soil water content to field capacity. The distribution uniformities (CUCs) were higher and lower than 80%, respectively. In treatments L2A and L3A, and L2B and L3B, the applied water depths corresponded to 50% and 150% of that applied to the LIA treatment. Because of rainfall events until the sampling date, no significant differences at 5% probability were found among treatments, when the variables were: leaf number, leaf area and dry matter. The F test for the contrast among the treatments with high and low uniformity was significant at 5% probability, when using 50% replacement of the water depth required by the crop. Significant differences were observed at 5% probability for pod number per plant among the treatments, when using 150, 100 and 50% replacement of the water depth required by the crop KEYWORDS: irrigation uniformity, sprinkler irrigation, yield. MANTOVANI, E. C.; FACCIOLI, G. G.; LEAL, B. G.; SOARES,A. A.; COSTA, L. C.; FREITAS, P. S. L. INFLUÊNCIA DA UNIFORMIDADE DE DISTRIBUIÇÃO DE ÁGUA E LÂMINA DE IRRIGAÇÃO NA PRODUTIVIDADE DO FEIJÃO 2 RESUMO O presente trabalho teve como objetivo avaliar a influência da uniformidade de distribuição de água e de três lâminas de irrigação nas variáveis de produção da cultura do feijão, utilizando um sistema de aspersão convencional, no período de inverno. Os tratamentos constaram de três lâminas de irrigação e dois níveis de uniformidade de distribuição de água, representados pelo coeficiente de uniformidade de Christiansen (CUC). Nos tratamentos L1A e L1B foi aplicada uma lâmina de água suficiente para elevar a umidade do solo à capacidade de campo, com uniformidade de distribuição (CUC) maior e menor que 80%, respectivamente. Nos tratamentos L2A e L3A, e L2B e L3B as lâminas aplicadas foram, respectivamente, 50% e 150% da lâmina aplicada no tratamento L1A. Não existiram diferenças significativas, a 5% de probabilidade, nos tratamentos para seguintes variáveis: número de folhas, área foliar e matéria seca, em razão das chuvas ocorridas até a data da amostragem. O teste F para o contraste entre os tratamentos de alta e baixa uniformidade com 50% de reposição da lâmina requerida pela cultura foi significativo a 5% de probabilidade. Observou-se diferenças significativas, a 5% de probabilidade entre os tratamentos com 150, 100 e 50% de reposição da lâmina requerida pela cultura, para o número de vagens por planta. UNITERMOS: Uniformidade de irrigação, irrigação por aspersão, produtividade.
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Elamri, Yassin, Bruno Cheviron, Annabelle Mange, Cyril Dejean, François Liron i Gilles Belaud. "Rain concentration and sheltering effect of solar panels on cultivated plots". Hydrology and Earth System Sciences 22, nr 2 (20.02.2018): 1285–98. http://dx.doi.org/10.5194/hess-22-1285-2018.
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Abstract. Agrivoltaism is the association of agricultural and photovoltaic energy production on the same land area, coping with the increasing pressure on land use and water resources while delivering clean and renewable energy. However, the solar panels located above the cultivated plots also have a seemingly yes unexplored effect on rain redistribution, sheltering large parts of the plot but redirecting concentrated fluxes on a few locations. The spatial heterogeneity in water amounts observed on the ground is high in the general case; its dynamical patterns are directly attributable to the mobile panels through their geometrical characteristics (dimensions, height, coverage percentage) and the strategies selected to rotate them around their support tube. A coefficient of variation is used to measure this spatial heterogeneity and to compare it with the coefficient of uniformity that classically describes the efficiency of irrigation systems. A rain redistribution model (AVrain) was derived from literature elements and theoretical grounds and then validated from experiments in both field and controlled conditions. AVrain simulates the effective rain amounts on the plot from a few forcing data (rainfall, wind velocity and direction) and thus allows real-time strategies that consist in operating the panels so as to limit the rain interception mainly responsible for the spatial heterogeneities. Such avoidance strategies resulted in a sharp decrease in the coefficient of variation, e.g. 0.22 vs. 2.13 for panels held flat during one of the monitored rain events, which is a fairly good uniformity score for irrigation specialists. Finally, the water amounts predicted by AVrain were used as inputs to Hydrus-2D for a brief exploratory study on the impact of the presence of solar panels on rain redistribution at shallow depths within soils: similar, more diffuse patterns were simulated and were coherent with field measurements.
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Rutledge, Alvin D. "Experiences with Conservation Tillage Vegetables in Tennessee". HortTechnology 9, nr 3 (styczeń 1999): 366–72. http://dx.doi.org/10.21273/horttech.9.3.366.
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Research yields of conservation tillage (CT) snap beans (Phaseolus vulgaris L.) and sweet corn (Zea mays L. var. rugosa Bonaf.) have been less than those produced under conventional tillage. This has been due to soil conditions at planting, the cover crop used, weed control and a lack of proper design in equipment for CT. However, some growers have been successful with CT for sweet corn using hairy vetch (Vicia villosa Roth.) as the cover crop. On-farm demonstrations of CT with cabbage (Brassica oleracea L. Capitata Group), pumpkins (Cucurbita pepo L.), tomatoes (Lycopersicon esculentum Mill.) and watermelons [Citrullus lanatus (Thunb) Matsum. & Nak.] have been successful and with good management it is commercially feasible under Tennessee conditions. Advantages include reduced soil erosion, cleaner products, more efficient application of crop protection chemicals, quicker planting after rainfall, lower energy costs and facilitation of harvest in wet weather. Disadvantages include reduced weed control, modifications of existing equipment, less uniformity in seed coverage and problems with transplanting, cover crop residue in mechanically harvested crops, possible delays in early harvest of fresh market crops due to delayed maturity and limited application of soil protective chemicals.
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Bimaprawira, Adikusuma, i Hasti Amrih Rejeki. "KETERKAITAN PERIODISITAS CURAH HUJAN DI DAERAH PESISIR DAN PEGUNUNGAN PROVINSI JAWA TIMUR DENGAN VARIABILITAS CUACA SKALA GLOBAL DAN REGIONAL". Jurnal Sains & Teknologi Modifikasi Cuaca 22, nr 2 (29.12.2021): 51–59. http://dx.doi.org/10.29122/jstmc.v22i2.4422.
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Intisari Jawa Timur merupakan wilayah yang memiliki variasi curah hujan yang dipengaruhi oleh fenomena cuaca global dan regional seperti Dipole Mode, El Nino Southern Oscillation (ENSO), Intertropical Convergence Zone, Madden Julian Oscillation, dan monsun. Topografi yang beragam juga menjadi faktor yang memengaruhi curah hujan di daerah Jawa Timur. Berbagai indeks digunakan untuk melihat aktivitas-aktivitas fenomena cuaca tersebut, seperti DMI untuk aktivitas Dipole Mode, NINO 3.4 untuk aktivitas ENSO, Indeks RMM untuk aktivitas MJO, WNPMI dan, AUSMI untuk aktivitas monsun. Pada penelitian ini digunakan analisis spektral dengan menggunakan metode Fast Fourier Transform untuk melihat periodisitas indeks masing-masing terhadap periodisitas curah hujan dari data 11 pos hujan yang terbagi menjadi 6 pos hujan daerah pesisir dan 5 pos hujan daerah pegunungan. Hasil dari penyeragaman periodisitas fenomena cuaca dengan curah hujan antara lain Dipole Mode (periodisitas 18 bulan), ENSO (periodisitas 18 dan 40 bulan), dan MJO (periodisitas 2 dan 3 bulan). Fenomena yang memengaruhi curah hujan di daerah pesisir maupun pegunungan secara dominan adalah fenomena monsun dengan diikuti ITCZ. Fenomena lain yang memengaruhi di daerah pesisir antara lain dominan MJO, serta fenomena ENSO dan Dipole Mode yang memengaruhi daerah Lamongan, Bunder, dan P3GI dengan kecenderungan lebih kuat pada fenomena Dipole Mode. Sementara itu, fenomena yang memengaruhi hujan di daerah pegunungan secara dominan adalah ENSO. Adapun fenomena lain yang memengaruhi hujan di daerah pegunungan antara lain fenomena MJO di daerah Tosari, serta daerah Kebon Teh Wonosari yang memiliki kecenderungan dipengaruhi oleh fenomena Dipole Mode meskipun pengaruhnya tidak signifikan. Abstract East Java is a region whose variations in rainfall are influenced by global and regional weather phenomena such as Dipole Mode, El Niño Southern Oscillation (ENSO), Intertropical Convergence Zone, Madden Julian Oscillation, and monsoons. Diverse topography is also a factor affecting rainfall in the area of East Java. Various indices are used to observe the activities of the weather phenomenon, such as DMI for Dipole Mode activities, NINO 3.4 for ENSO activities, RMM Index for MJO activities, as well as WNPMI and AUSMI for monsoon activities. In this study, spectral analysis was used by utilizing the Fast Fourier Transform method to see the periodicity of each index against the periodicity of rainfall from the 11 rainwater data points, which were divided into 6 coastal data points and 5 mountainous data points. Uniformity of weather phenomena with rainfall result among others Dipole Mode (18 months periodicity), ENSO (18 and 40-month periodicity), and MJO (2 and 3-month periodicity). Phenomena that affect rainfall in coastal and mountainous areas predominantly are monsoon, followed by ITCZ. Other phenomena affecting the coastal area include MJO dominant, and the ENSO and Dipole Mode phenomena that affect the Lamongan, Bunder, and P3GI regions with a stronger tendency to the Dipole Mode phenomenon. Another phenomenon that influences rain in the mountainous area is dominantly ENSO, while other phenomena include MJO phenomena in the Tosari area and Kebon Teh Wonosari region which has a tendency to be influenced by the Dipole Mode phenomenon despite the insignificant effect.
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Bell, M. J., B. J. Bridge, G. R. Harch i D. N. Orange. "Rapid internal drainage rates in Ferrosols". Soil Research 43, nr 4 (2005): 443. http://dx.doi.org/10.1071/sr04063.
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Adoption of conservation tillage practices on Red Ferrosol soils in the inland Burnett area of south-east Queensland has been shown to reduce runoff and subsequent soil erosion. However, improved infiltration resulting from these measures has not improved crop performance and there are suggestions of increased loss of soil water via deep drainage. This paper reports data monitoring soil water under real and artificial rainfall events in commercial fields and long-term tillage experiments, and uses the data to explore the rate and mechanisms of deep drainage in this soil type. Soils were characterised by large drainable porosities (≥0.10 m3/m3) in all parts of the profile to depths of 1.50 m, with drainable porosity similar to available water content (AWC) at 0.25 and 0.75 m, but >60% higher than AWC at 1.50 m. Hydraulic conductivity immediately below the tilled layer in both continuously cropped soils and those after a ley pasture phase was shown to decline with increasing soil moisture content, although the rate of decline was much greater in continuously cropped soil. At moisture contents approaching the drained upper limit (pore water pressure = –100 cm H2O), estimates of saturated hydraulic conductivity after a ley pasture were 3–5 times greater than in continuously cropped soil, suggesting much greater rates of deep drainage in the former when soils are moist. Hydraulic tensiometers and fringe capacitance sensors monitored during real and artificial rainfall events showed evidence of soils approaching saturation in the surface layers (top 0.30–0.40 m), but there was no evidence of soil moistures exceeding the drained upper limit (i.e. pore water pressures ≤ –100 cm H2O) in deeper layers. Recovery of applied soil water within the top 1.00–1.20 m of the profile during or immediately after rainfall events declined as the starting profile moisture content increased. These effects were consistent with very rapid rates of internal drainage. Sensors deeper in the profile were unable to detect this drainage due to either non-uniformity of conducting macropores (ie. bypass flow) or unsaturated conductivities in deeper layers that far exceed the saturated hydraulic conductivity of the infiltration throttle at the bottom of the cultivated layer. Large increases in unsaturated hydraulic conductivities are likely with only small increases in water content above the drained upper limit. Further studies with drainage lysimeters and large banks of hydraulic tensiometers are planned to quantify drainage risk in these soil types.
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Ahmad, Siti Zubaidah, Mohd Sanusi S. Ahamad i Mohd Suffian Yusoff. "A Comprehensive Review of Environmental, Physical and Socio-Economic (EPSE) Criteria for Spatial Site Selection of Landfills in Malaysia". Applied Mechanics and Materials 802 (październik 2015): 412–18. http://dx.doi.org/10.4028/www.scientific.net/amm.802.412.
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Location of municipal solid waste landfills in Malaysia has been attributed to causing bad odour, dust, litter, unattractive neighbourhoods, groundwater contamination, hazardous waste pollution and etc. Therefore, proper selection criteria are very important in preliminary siting of new landfill to avoid undesirable long-term effects. This article presents a comprehensive review of landfill spatial siting criteria and their frequency of occurrence (ranked order) found in literatures. The highest ranked criterion is the surface water and the lowest is climate/rainfall density. The dissimilarity in the criteria is found to be specifically influenced by published guidelines or policies from respective countries. In addition, group ranking of spatial criteria from frequency study made on Malaysian local literatures shows that wind factor and infrastructure (utilities) has never been considered in landfill site selection process here. These factors cannot be ignored because enhancing the condition of social, economic and environmental efficiency is part of promoting sustainable development. Subsequently, a benchmarking process of common environmental, physical and socio-economic (EPSE) criteria made with Malaysian landfill siting guideline; National Strategic Plan for Solid Waste Management and Environmental Impact Assessment Guidelines for Municipal Solid Waste and Sewage Treatment and Disposal Project. The bench mark process is useful for research references and its uniformity provides efficient site selection process in solid waste management.