Raining Conditions Research Articles

Evaporation of intercepted rainfall–Comparing canopy water budget and energy balance related long term measurements at a Norway spruce site

Rain interception of a Norway spruce stand was analyzed based on canopy water balance measurements Emass and for two eddy covariance (EC) related methods covering a long period (2008–2018). Emass was calculated as residual between gross rainfall above and net rainfall below the canopy. EC related observations are based on the water equivalent either (i) directly measured by eddy covariance (ETEC) or (ii) as residual in the Energy Balance equation (ETEB). To relate the different methods to wet canopy conditions, the Rutter model was used to dynamically calculate water storage in the canopy. Finally, the different time series were integrated over the duration of modeled interception events.The canopy water balance shows a mean annual gross precipitation of 936 ± 173 mm/year of which 376 ± 56 mm/year evaporated due to interception. The majority of rainfall events (81%) is characterized by a depth <5 mm, which leads to a high fraction of annual precipitation being captured by the canopy surface (0.41). The application of the Rutter model yielded good agreement between observed and modeled throughfall and served as a reasonable standard to define interception events. Wet canopy evaporation as the residual of the energy balance ETEB and from gas analyzer measurements ETEC are both systematically underestimating Emass. The mean annual underestimation of Emass is 145 mm/year for ETEB and 288 mm/year for ETEC. Most of the discrepancy can be mainly explained by an underestimation of turbulent fluxes, at which data is most affected during raining conditions. An analysis of the linear relation between the annual sum of turbulent fluxes and available energy shows the lowest slope (0.57 ± 0.15) for measurements during rainfall, while the highest slope (0.76 ± 0.03) occurs under completely dry conditions. Both fluxes should be gap-filled and corrected separately for dry (transpiration) and wet (interception) conditions in order to determine proper amounts of evapotranspiration with the eddy covariance method.

Performance Test of Solar – Powered Ice Maker Machine: Case Study in Bantul, Yogyakarta

Research on performance test of a solar-powered ice maker machine has been conducted in Bantul, Yogyakarta. This study aimed to observe the correlation between intensity of sunlight to the power battery capacity rates generated from solar panels in regard with the performance of ice maker machine. The testing was conducted during various weather conditions i.e. sunny, cloudy and light rain. The type of ice maker observed was a flake ice maker machine with specifications of the production capacity of 105 - 120 kgs/day, producing flake ice with dimensions of 2 x 3 x 3 mm3. The energy of the machine was generated by nine solar panels with maximum power of 200 Wp (watt peak) per panel. A set of three panels was arranged in series, it was then coupled to other sets in parallel. The results showed that the power battery capacity was in corresponded to the sunlight intensity during sunny weather with the correlation: y = 0.009x - 26.08, while during cloudy dan raining conditions, the power capacity rates of the battery showed a declining with the correlation: y = 0.008x - 23.92 and y = 0.007x + 69.41, respectively. The ice production capacity during sunny, cloudy and light rainy weathers were 4.34 kg ice/hour; 4.63 kg ice / hour and 4.17 kg ice / hour respectively. Input power from solar panels depends on the intensity of sunlight. The ice produced by ice makers in cloudy weather conditions is much greater than the ice produced during sunny or rainy weather conditions.

Application of TRIZ Method in Developing Vehicle Lane Support System Testing Infrastructure for Raining Condition

&#x0D; &#x0D; &#x0D; Theory of Inventive Problem Solving (TRIZ) is an inventive problem-solving method developed to find a solution for issues involving contradictions. The TRIZ method was applied to develop a new method of simulating raining weather conditions for vehicle lane support system (LSS) on-road testing infrastructure. The objective of the project was to develop a mechanical solution capable of dispensing a consistent amount of water to a moving vehicle to simulate raining weather conditions, while at the same time it is portable and easy to set up. Based on the requirement, the TRIZ 40 inventive principles were applied as the solution, based on the principles of “the other way around”, “segmentation”, “dynamicity” and “feedback”. The specific solution generated based on the inventive principles identified was to make both the vehicle and the rain simulating machine movable during the on-road test. This is achieved by creating a customized rain machine that can be fitted onto a moving vehicle. This simple setup enabled both vehicle-under-test (VUT) and the rain machine vehicle to move simultaneously during the test, at any test speed and type of test track desired. Furthermore, the rain machine itself is designed with the capability to dispense the water by using a control unit, hence making the testing method safer and less human effort required. Based on the literature review, there is yet no similar solution for simulating raining conditions in LSS on-road test made using the same principle developed in this project. The innovative portable rain machine developed in this project could also be applied for other Advanced Driver Assistance System (ADAS) test protocols requiring similar raining testing conditions especially involving moving VUT.&#x0D; &#x0D; &#x0D;

Dynamic Response of High-Speed Train-Track-Bridge Coupling System Subjected to Simultaneous Wind and Rain

The Lanzhou-Xinjiang High-speed Railway runs through a region of over 500[Formula: see text]km that is amenable to frequent winds. The strong wind and rainfall pose a great threat to the safe operation of high-speed trains. To tackle the aforementioned climate challenges, this paper investigates the dynamic response of the high-speed train-track-bridge coupling system under the simultaneous action of winds and rains for the safe operation of trains. Specifically, there are four main objectives: (1) to develop a finite element model to analyze the dynamic response of the train-track-bridge system in windy and raining conditions; (2) to investigate the aerodynamic loads posed to the train-track-bridge system by winds and rains; (3) to evaluate the effects of wind speed and rainfall intensity on the train-track-bridge system; and (4) to assess the safety of trains at different train speeds and under various wind-rain conditions. To this end, this paper first establishes a train-track-bridge model via ANSYS and SIMPACK co-simulation and the aerodynamics models of the high-speed train and bridge through FLUENT to form a safety analysis system for high-speed trains running on the bridge under the wind-rain conditions. Then, the response of the train-track-bridge system under different wind speeds and rainfall intensities is studied. The results show that the effects of winds and rains are coupled. The rule of variation for the train dynamic response with respect to various wind and rain conditions is established, with practical suggestions provided for control of the safe operation of high-speed trains.

Study of tropospheric scintillation effects in Ku-band frequency for satellite communication system

Scintillation is a rapid fluctuation of an electromagnetic waves in terms of phase and amplitude due to a small-scale inconsistency in the transmission path (or paths) with time. Scintillation exists continuously throughout a day whether during raining or clear sky conditions. The raw signal data need to exclude other propagations factors that include signal fluctuations to further understand the scintillation studies. This paper presents the analysis of tropospheric scintillation data from January 2016 till December 2016 at Ku-band frequency of 12.202 GHz beacon signal. The experimental data from MEASAT 3B were collected and analyzed to see the effect of tropospheric scintillation. The elevation angle of the dish antenna is 77.45o. The highlighted objectives are to analyze the scintillation data at Ku-band, and to compare and validate the results with other scintillation models. The result shows that the stipulated scintillation analysis has higher amplitude, which is 0.73 dB compared to other scintillation analysis which has lower scintillation amplitude: 0.45 dB (Karasawa), 0.42 dB (ITU-R), 0.4 dB (Nadirah &amp; Rafiqul), 0.42 dB (Van De Kamp) and 0.11 dB (Anthony &amp; Mandeep).

Luminescent solar concentrators performing under different light conditions

The use of luminescent solar concentrators (LSCs) is considered a promising option to impart energy harvesting capability to buildings with minimal alternation to the building structure. To fill the gap between fundamental research and practical application, this study investigated the performance (power conversion efficiency, ηLSC and power concentration ratio, C) of the LSCs of different sizes under different light conditions including simulated sunlight condition, outdoor sunny, overcast and raining conditions, and indoor condition employing four different types of light bulbs (i.e., incandescent, halogen, fluorescent and light-emitting diode). It was observed that the LSCs exhibited higher one-sun performance under outdoor sunny condition than under simulated sunlight. Under overcast and raining conditions, ηLSC decreased significantly with the increase of the device size. Under indoor incandescent and halogen light conditions, the LSCs exhibited low ηLSC due to the low percentage of the visible portion in the light spectrum. Surprisingly high ηLSC boosted by 50% compared to the outdoor sunny condition was obtained in the LSCs under fluorescent and LED light conditions. This research suggested very promising application of the LSCs in indoor light energy recycling, which has not been proposed before.

Towards variational retrieval of warm rain from passive microwave observations

Abstract. An experimental retrieval of oceanic warm rain is presented, extending a previous variational algorithm to provide a suite of retrieved variables spanning non-raining through predominantly warm raining conditions. The warm rain retrieval is underpinned by hydrometeor covariances and drizzle onset data derived from CloudSat. Radiative transfer modelling and analysis of drop size variability from disdrometer observations permit state-dependent observation error covariances that scale with columnar rainwater during iteration. The state-dependent errors and nuanced treatment of drop distributions in precipitating regions are novel and may be applicable for future retrievals and all-sky data assimilation methods. This retrieval method can effectively increase passive microwave sensors' sensitivity to light rainfall that might otherwise be missed. Comparisons with space-borne and ground radar estimates are provided as a proof of concept, demonstrating that a passive-only variational retrieval can be sufficiently constrained from non-raining through warm rain conditions. Significant deviations from forward model assumptions cause non-convergence, usually a result of scattering hydrometeors above the freezing level. However, for cases with liquid-only precipitation, this retrieval displays greater sensitivity than a benchmark operational retrieval. Analysis against passive and active products from the Global Precipitation Measurement (GPM) satellite shows substantial discrepancies in precipitation frequency, with the experimental retrieval observing more frequent light rain. This approach may be complementary to other precipitation retrievals, and its potential synergy with the operational passive GPM retrieval is briefly explored. There are also implications for data assimilation, as all 13 channels on the GPM Microwave Imager (GMI) are simulated over ocean with fidelity in warm raining conditions.

Performance of pervious concrete pavement under various raining conditions

Pervious concrete is one of the most effective environmentally friendly products which can be used as a paving material to diminish runoff and increase safety. To better understand the behaviour of pervious concrete pavement (PCP), its performance must be extensively monitored and evaluated. The permeability rate of PCP is the key criterion in the evaluation of its performance particularly in low duty applications such as sidewalks. A few permeability rate models have been developed to date for PCP. However, the effect of raining conditions on the permeability rate has not received enough attention. The main aim of this research is to study the permeability rate models over two raining conditions i.e. continuous and intermittent for PCP in a typical sidewalk application. For this purpose, the permeability rate of PCP is tested in-situ over time on a PCP slab with various time intervals between consecutive tests to simulate continuous and intermittent raining conditions over almost four months. Based on the acquired data, it is concluded that the permeability rate of PCP over different raining conditions have a statistically significant difference. Moreover, short-term permeability rate degradation models for general, continuous, and intermittent conditions are developed using the regression method and successfully validated applying the n-fold data-split technique.

Impacts of Weather and Environmental Conditions on Mobile Communication Signals

The impacts of weather and environmental conditions on mobile communication signals were determined in this study. A Glo mobile communication network operating in the 900MHz band was considered. The Glo fixed base transceiver station (BTS) location at Gloworld in Benin City was considered. A frequency-signal tracker software, version 2.5.1 was installed and configured into a notebook Intel palm top, relative parameters data were obtained from 200 meters from the Glo BTS from 28th of July to 31st of August 2016, with data obtained hourly. Morning, afternoon and evening, and dry weather, fog weather and raining conditions was based on the statistical central tendency parameters. The average refractivity gradient observed was -61.3 N/km. It was observed that dry weather, signal strength variation was within 32 dBm, fog, variation was within 34 dBm range, while the variation of rain was within 38 dBm range indicating higher variation. It was observed that the more the mobile station move away from the BTS the higher the signal loss and that temperature and refractivity gradient has 0.50 and 0.42 positive correlations. In addition, relative humidity and pressure possesses negative correlations of -0.50 and -0.44 respectively.

Study of rain attenuation effects for 5G Mm‐wave cellular communication in tropical location

Millimetre (mm)-wave communication is a viable solution to the future 5G cellular services. For different temperate locations, rain attenuation does not contribute significantly to the overall path loss at the mm-wave band for a small cell size of 200 m. However, in various tropical locations, the rain attenuation effect cannot be ignored even for this small cell size of the system. If the authors increase either frequency or path length, the attenuation increases significantly under tropical raining conditions. In this study, time series of predicted rain rate values are used for real-time prediction of rain attenuation over terrestrial paths.

Introduction of a Cost Effective Method for Analysing Engine Intake Ice Removal Device for Small Aircraft

As the need for personal air transport increases significantly, new aircraft and/or its components are required to be designed and developed together with expectations for guarantying the high level flight safety. Since smaller aircraft manufacturers don’t have the infrastructural and experimental resources for complex investigations, analysis of engine components with especial care for the behaviour of particle separation components in the inlet air duct for example, smarter, more efficient solutions have to be developed. CFD software gives an opportunity to simulate the trajectories of different type of particles, such as hailstones, dust, or even liquid water droplets. Hence, in this study an upper-wing type, two engines thrusted, small turboprop aircraft’s integrated engine air intake device has been analysed, to prove the effectivity of the aircraft performance in the considered raining and icing conditions. The flow field has been discretized with a detailed, hybrid mesh using hexa elements at the simpler parts, and tetra elements, where the geometry is more complex. Inflation layers have been inserted on the wall-type surfaces, with especial care to the problematic parts, where the y+ number is predictably higher. The inlet boundary conditions of the model have been extracted from a larger, complex pre-simulation, performed in a previous study. Standard Reynolds Averaged Navier-Stokes equations have been considered with Shear Stress Transport turbulence model. Solid (ice) and liquid particles have been defined, and their trajectories are investigated by using fully coupled model. The interaction of the wall-fluid particle has been taken into consideration.

The first flush effect of different urban underlying surfaces through artificial simulated rainfall

Three kinds of underlying surfaces: asphalt road, impervious tiles and grassland at Chang’an University in south second ring road of Xi’an were chosen as testing sites. Self-made device was used to moderate rainfall with different raining conditions: uniform rainfall intensity of 0.3mm/min, 0.5mm/min, 1.0mm/min; front peak type rainfall and back peak type rainfall. The pollutants in the runoff were measured, that included TN, TP, NO3--N, NO2--N, NH4+-N, PO43--P and PN M(V) curves and MFF30 values were analysed to drew these conclusions: under uniform rainfall intensity of 0.3mm/min, 0.5mm/min, 1.0mm/min, the mean values of MFF30 from asphalt road runoff were 0.47, 0.42, 0.41, the mean values of MFF30 from watertight tiles runoff were 0.40, 0.39, 0.38, the mean values of MFF30 from grassland runoff were 0.33, 0.34, 0.32. The first flush magnitude decreased with the increasing of rainfall intensity on asphalt road and watertight tiles, while the first flush intensity first increased and then decreased with the increasing of rainfall intensity on grassland. The mean values of MFF30 from the front peak type rainfall were larger than that from the back peak type rainfall on both asphalt road and watertight tile. The mean values of MFF30 from the back peak type rainfall were larger than that from the front peak type rainfall on grass. Grassland should be built around asphalt road and watertight tiles to attenuate first flush effect.

Silicone-Infused Antismudge Nanocoatings.

A polyurethane-based NP-GLIDE coating that bears on its surface and in its interior nano-pools of a grafted liquid ingredient for dewetting enablement is obtained from casting and curing a film comprising a triisocyanate, a polyol (P1), and a graft (g) copolymer of P1 and poly(dimethylsiloxane) (P1-g-PDMS). A silicone-infused NP-GLIDE (SINP-GLIDE) PU coating is obtained from cocasting the NP-GLIDE precursors with a free silicone oil (SO) or SO mixture (SOs). This paper reports the preparation of the novel SINP-GLIDE coatings and discusses the effect of changing the amount and type of the infused SO as well as the coating formation conditions on their optical clarity. Also reported are the contact and sliding angles of various test liquids on the NP-GLIDE and SINP-GLIDE coatings, and the data variation trends are rationalized using existing theories. Further, the stable water sliding performance of the SINP-GLIDE coatings under simulated raining and other conditions is demonstrated. The improved and stable water sliding performance of the SINP-GLIDE coatings facilitates their practical applications.

Analysis of Association Rules between Hourly Meteorological Factors and PM2.5 Water-Soluble Inorganic Ions in Lanzhou, China

With a continuous liquefaction sampling device for atmospheric fine particles, we built an online system for real-time monitoring of atmospheric water-soluble inorganic ions and meteorological factors. The association rules between water-soluble inorganic ions and meteorological factors in atmospheric fine particles (PM2.5) sampled hourly between April and May 2010 in Lanzhou, China were mined out using Apriori algorithm. Also the real-time effects of meteorological factors on the mass concentrations of water-soluble inorganic ions were investigated. This paper examines seven most recent patents between October 2008 and June 2014 in the area of Business Intelligence and Atmospheric Sciences. The results show that sulfates were dominant in the composition of atmospheric water-soluble inorganic ions. The major meteorological factor affecting the mass concentrations of water-soluble inorganic ions was the joint action of temperature and relatively humidity. The ion concentrations were higher during daytime than at night, and increased at high-temperature and low-relatively humidity conditions, indicating that the photochemical effect significantly promoted the generation of water-soluble inorganic ions. The NW wind would carry the ions from the industrial zone in West Lanzhou to the downtown, since the atmospheric transport elevated the concentrations of water-soluble inorganic ions. When strong wind passed, ρ(Ca2+) increased from inward transport, but the mass concentrations of other water-soluble inorganic ions decreased. The concentrations of all ions decreased at high-relatively humidity and raining conditions. Keywords: Water-soluble inorganic ions, PM2.5, Lanzhou, sources.

Investigation of DC discharge behavior of polluted porcelain post insulator in artificial rain

The surface discharge of natural polluted post insulators in rain is an important factor which affects the external insulation of HVDC converter stations. With the artificial contamination flashover tests in rain for porcelain post insulators, this paper has obtained the flashover process and discharge characteristics of the test samples under artificial rain condition. It has been observed that the discharge of water droplet on the shed edge plays a very important role in the whole process of pollution flashover in rain. When a water droplet hangs on the shed edge, the maximum electric field strength appears in the vicinity of vertices, rather than the lateral area of the water droplet. Thus, the streamer propagates only in the direction of the air gap between sheds. Moreover, the influence of raining conditions including intensity and conductivity on the flashover voltage has been investigated. Test phenomena also indicate that due to the different damp and dry band conditions, surface discharge characteristics of post insulator in rain are different with that in fog, which lead to different flashover voltages. This study provides a new understanding for the HVDC insulator pollution flashover in wet environment.

Chromium Addition Effect on Wear Properties of Cast-Iron Material

A new cast iron material with a higher Cr content than usual is analyzed by chemical, micro-structural and friction coefficient point of view. The material was obtained by classical melting and the results compared with the experimental results obtained from a standard cast-iron used for applicative disk brake. Four different mechanical solicitation rates were used on the same material surface and the same load. The solicitation regime can be considered as semi-liquid and similar to a raining day experimental conditions. In this paper no thermal considerations were present or discussed. The results present a bigger friction coefficient of the new material and further considerations are necessary for example in a different friction regime.

Morphology of Rain Water Channeling in Systematically Varied Model Sandy Soils

We visualize the formation of fingered flow in dry model sandy soils under different raining conditions using a quasi-2d experimental set-up, and systematically determine the impact of soil grain diameter and surface wetting property on water channelization phenomenon. The model sandy soils we use are random closely-packed glass beads with varied diameters and surface treatments. For hydrophilic sandy soils, our experiments show that rain water infiltrates into a shallow top layer of soil and creates a horizontal water wetting front that grows downward homogeneously until instabilities occur to form fingered flows. For hydrophobic sandy soils, in contrast, we observe that rain water ponds on the top of soil surface until the hydraulic pressure is strong enough to overcome the capillary repellency of soil and create narrow water channels that penetrate the soil packing. Varying the raindrop impinging speed has little influence on water channel formation. However, varying the rain rate causes significant changes in water infiltration depth, water channel width, and water channel separation. At a fixed raining condition, we combine the effects of grain diameter and surface hydrophobicity into a single parameter and determine its influence on water infiltration depth, water channel width, and water channel separation. We also demonstrate the efficiency of several soil water improvement methods that relate to rain water channelization phenomenon, including pre-wetting sandy soils at different level before rainfall, modifying soil surface flatness, and applying superabsorbent hydrogel particles as soil modifiers.

M-ary Bayes Estimator Selection for QuikSCAT Simultaneous Wind and Rain Retrieval

While originally designed only for wind measurement, the QuikSCAT scatterometer is capable of making wind and rain estimates over the ocean. Three separate estimators are used, a wind-only estimator, a rain-only estimator, and a simultaneous wind-rain estimator. No one of the estimators is suitable under all wind and rain conditions. We therefore propose a Bayesian estimator selection technique whereby the appropriate estimator can be selected from the estimates themselves. This paper introduces the Bayes estimator selection technique and discusses its application to QuikSCAT wind and rain estimation for conventional (25-km) resolution products. Results indicate that using Bayes estimator selection can improve both the bias and mean-squared error of wind estimates in both raining and nonraining conditions, as well as provide an improved rain flag.

Ice accretion on superhydrophobic aluminum surfaces under low-temperature conditions

Abstract An icephobic surface is always desirable for high voltage overhead transmission lines to reduce ice formation on their aluminum surface, especially in a low temperature and high humidity environment. This work studied the effects of two hydrophobic coatings when applied on aluminum surfaces under cold and raining conditions in an artificial climatic chamber. Compared with bare hydrophilic aluminum surfaces, the aluminum surfaces coated with hydrophobic room temperature vulcanized silicone rubber (RTV SR) did resist ice formation but was covered by a layer of ice after 30 min of spraying supercooled water. However, a superhydrophobic coating can largely prevent ice formation on the surface except a few ice growth spots at a working temperature of − 6 °C. Furthermore, such coating keeps average water contact angles larger than 150° even at a working temperature of − 10 °C. This highly icephobic performance of the above samples is mainly attributed to the superhydrophobic property of the coating, which was obtained on micronanoscale structured aluminum surfaces after the low surface-energy stearic acid treatment.

Feature Selection for Robust Classification of Crack and Drop Signals

This paper presents a study to the problem of features selection for accurate recognition of crack signals in raining conditions, using a multilayer perceptron and a radial basis function neural network. The features extraction process is accomplished for two time frames: in the first time frame the presence of the signal reflection is minimal; in the later a wider window include signal reflections at the specimen edges. An extensive set of 90 features (41 of them are novel), 67 in the time domain and 23 in the frequency domain, are extracted from the normalized signals and are sorted according to Fisher ratio (F-ratio). The signals database consists of over than 20,000 simulated cracks and drops signals. The NNs classification accuracy of a single crack signal in rain conditions using the most robust features ranges from 80.08% to 99.08%, which remains in the same levels when white-Gaussian noise up to 0 dB signal-to-noise ratio is added to the signal.