Maximum Instantaneous Wind Research Articles

Data-driven calibration of cup anemometer based on field measurements and artificial neural network for wind measurement around buildings

In recent years, high-precision sensors such as ultrasonic anemometer have been commonly used for wind measurement. However, conventional sensors such as cup anemometer is yet to be completely replaced owing to its advantages of low cost and high robustness. Thus, to improve the measurement accuracy of cup anemometer in practical applications, this paper proposes a data-driven calibration strategy based on field measurements. Regarding the data sources, two datasets were acquired at multiple locations in the vicinity of the reference buildings to construct a calibration (regression) model. For model development, we proposed artificial neural network (ANN)-based models with cup anemometer measurements as input and ultrasonic anemometer measurements as output. Compared with the baseline models (Kristensen's models and multiple linear regression models) on several performance metrics, the results demonstrated that ANN models with nonlinear computational ability improved the calibration of the measurements. At a location situated on the open space (building side), the ANN models reduced the mean of the relative errors of mean wind speed, maximum instantaneous wind speed, standard deviation, turbulence intensity, and gust factor by approximately 9% (9%), 5% (3%), 2% (10%), 13% (23%), and 6% (12%), respectively, in comparison to the noncalibrated cup anemometer measurements.

Pilot Study to Evaluate Performance of Frost-Yuzu Fruit Trees under Protected Cultivation

This study was initiated to observe the performance of yuzu (Citrusjunos Sieb. ex Tanaka) fruit trees when affected by a late freezing in 2018 and to evaluate the recovery of frost-damaged trees during post management under protected cultivation. A—4.9 °C of minimum daily temperature and 40-day drought occurred during dormancy, which then received heavy precipitation between early- and mid-March, with 15 m s−1 more than maximum instantaneous wind speeds frequently observed. This resulted in observed decreases in height, width and volume as well as in fruiting, fruit weight and yield, as well as yield index in 60–90% defoliated yuzu trees, in addition to higher rates of shoot dieback compared to trees that experienced only 0–30% defoliation. Lower performance and recovery rates of trees grown on flat land compared to trees on sloped land were also observed. Tree and net windbreaks did not significantly affect tree vegetative growth and fruit productivity but were found to have lowered shoot mortality in 2018 and 2019. Mulch with an irrigation after freezing or foliar urea application was shown to effectively increase vegetative tree growth and fruit productivity and reduce shoot mortality.

Association of meteorological factors with the frequency of primary rhegmatogenous retinal detachment in Japan

This 5-year ecological study assessed the association between meteorological factors and rhegmatogenous retinal detachment (RRD) frequency in 571 eyes of 543 cases of primary RRD at the Jikei University Kashiwa Hospital, Japan. We examined the monthly and seasonal distributions of RRD frequency using one-way analysis of variance. We then evaluated the relationship between monthly RRD frequency and 36 meteorological parameters using Poisson regression analysis. Furthermore, we developed multivariate regression models to predict the frequency of RRD based on specific meteorological parameters. There were no significant differences in the monthly and seasonal distributions (monthly, P = 0.99; seasonal, P = 0.77). The following eight parameters were associated with a lower RRD frequency: average sea level barometric pressure and average daily variation of average temperature, maximum temperature, maximum wind speed, maximum instantaneous wind speed, humidity, average sea level barometric pressure, and minimum sea level barometric pressure (P < 0.05). The best model to predict RRD frequency showed sufficient validity (Akaike’s information criterion with correction for small sample size = 332.0) and predictive power (proportion of variance explained by cross-validation method = 84.82%, 95% CI 72.18–93.72). In conclusion, low atmospheric pressure and high meteorological stability are significantly associated with a higher frequency of RRD. In addition, the Poisson regression analysis showed sufficient validity and predictability for predicting RRD frequency.

Maximum Instantaneous Wind Speed Forecasting and Performance Evaluation by Using Numerical Weather Prediction and On-Site Measurement

A maximum instantaneous wind speed forecast methodology based on the autoregressive with exogenous inputs (ARX) model is proposed, in which numerical weather prediction and on-site measurement are used as inputs and the model parameters are estimated using non-parametric regression with forgetting factors. The accuracy of prediction using a proposed dynamic model is then evaluated and compared to the conventional static model output statistics (MOS) model. It is found that the prediction accuracy is improved by utilizing numerical weather prediction with a higher horizontal resolution. Finally, the predictability of the maximum instantaneous wind speed higher than 15m/s is evaluated using the receiver operating characteristic (ROC) curve and the area under the curve (AUC). The optimal quantile level of the maximum instantaneous wind speed is derived using a cost function.

Development of probabilistic assessment framework for pedestrian wind environment using Bayesian technique

This study extends the assessment framework proposed by Murakami et al. (1986) for the pedestrian wind environment to a fully probabilistic method by implementing Bayesian modeling. The method quantifies the uncertainties in constructed models based on the measured wind data and the results of the assessment. To model the probabilities of the daily maximum mean wind speed and wind direction, we employed the Weibull distribution and categorical distribution, respectively. The parameters defining the probability distributions were probabilistically modeled using Bayesian techniques. Using the wind data measured at the Meteorological Observatory of Tokyo, we demonstrated the effectiveness of the proposed method. The results showed that the wind direction probability and each parameter of the Weibull distribution could be estimated in the form of a posterior probability density function. Using the constructed models, we predicted the exceedance probability of the daily maximum instantaneous wind speed and evaluated the wind environment index (rank) in a city model. We provided a discrete rank scale in the form of a probability distribution, which enables us to quantify the evaluation uncertainties. Additionally, we clarified the effect of varying the amount of data used for the model construction. The uncertainty of the exceedance probability decreased with the amount of data. When only 1 year of data was used, some evaluation points possibly changed over three ranks. Even when 5-year observation data was used, the evaluated rank of some points varied within the range of uncertainty, thereby highlighting the importance of uncertainty quantification in the wind environment assessment.

Validation of dynamic response of a 2-MW hybrid-spar floating wind turbine during typhoon using full-scale field data

Accurate estimation of the dynamic behavior of Floating Offshore Wind Turbines (FOWTs) under typhoon environment is essential to design and install FOWTs in a prone area of typhoons such as around Japan. Up to now, extensive efforts for development of design tools for FOWTs have been made, and nowadays several design tools are available. Needless to say, it is of utmost importance that the engineering design tools have been verified and validated for the real physical phenomena before being applied to real designs/projects with confidence. Much efforts have thus been made as code-to-code comparisons and by validations using model test data. Validations of the design tools using full-scale field data for FOWTs have also been made, but available open literatures are quite limited, particularly for design-driving extreme cases. In this paper, we describe the analysis of the dynamic response of a 2-MW spar-type FOWT at the time of typhoon attack in the actual sea area. The central atmospheric pressure of the typhoon at the closest time was 965 hPa, the maximum instantaneous wind speed at the hub height was 52.2 m/s, and the maximum significant wave height was 6.9 m. The dynamic responses under the typhoon environment are numerically simulated by using the time-series records of the wind speed, the wind direction, the wave height, the wave direction, the current speed, and the current direction which were acquired during the typhoon passing through close to the FOWT. Then the simulated motion responses are compared with the measured motion responses for the same durations. By the comparisons, the numerical simulation tool which was used for the design of the FOWT has been partially validated. It has also been confirmed that the spatial coherence of the wind speed has a significant effect for the platform motions, particularly for yaw motion.

The 9–11 November 2013 Explosive Cyclone over the Japan Sea-Okhotsk Sea: Observations and WRF Modeling Analyses

During the period from 9 to 11 November 2013, an explosive cyclone (EC) occurred over the Japan Sea-Okhotsk Sea. This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when moving northeastward. It had a minimum sea level pressure of 959.0 hPa, a significant deepening rate of central pressure of 2.9 Bergeron, and a maximum instantaneous wind speed of 42.7ms−1. This paper aims to investigate the conditions that contributed to the rapid development of this low-pressure system through analyses of both observations and the Weather Research Forecasting (WRF) modeling results. The evolutionary processes of this EC were examined by using Final Analyses (FNL) data, Multi-Functional Transport Satellites-1R (MTSAT-1R) data, upper observation data and surface observation data. WRF-3.5 modeling results were also used to examine the development mechanism of this EC. It is shown that the interaction between upper-level and low-level potential vorticity seemed to be very essential to the rapid development of this EC.

Effects of typhoons on an arthropod community centered upon a leaf gall midge, Pseudasphondylia neolitseae (Diptera: Cecidomyiidae) and its host plant, Neolitsea sericea (Lauraceae) through leaf fall and late‐season shoot production

AbstractWe evaluated effects of strong typhoons on populations of a gall midge Pseudasphondylia neolitseae (Diptera: Cecidomyiidae) and its associated arthropods through leaf fall of the host plant, Neolitsea sericea (Lauraceae). The very strong typhoon No. 13 in 1985 (“8513‐Pat”) caused heavy leaf fall particularly on forest edge trees, resulted in the larval death of gall midge and its endoparasitoid Gastrancistrus sp. (Hymenoptera: Pteromalidae). The typhoons were not directly responsible for the larval death of an ectoparasitoid Bracon tamabae (Hymenoptera: Braconidae) and a successor Lasioptera yadokariae (Diptera: Cecidomyiidae) that utilizes vacant galls after the departure of inhabitants. However, reduction in the number of galls possibly made their searching behavior for oviposition sites inefficient because their abundance relies on the gall density. The heavy leaf fall promoted lammas shoot production, which caused the reduction of number and length of the following spring shoots. The shortage of spring shoots must be influential to the gall midge females in searching oviposition sites, and the short spring shoots were not useful for oviposition and larval boring by Oberea hebescens (Coleoptera: Cerambycidae). We compared strength of the effects between the typhoons that attacked Kagoshima in 1985 and 1993, and Okinawa in 2015 and 2018, and concluded that typhoons with the maximum instantaneous wind velocity exceeding 50 m/s caused heavy leaf fall and lammas shoot production on N. sericea trees growing at forest edge but not on those inside forest.

Analysis on Wind Field Characteristics of the First Hundred Kilometers of Wind Area along Nanjiang Railway

The wind data in wind monitoring point of 2015, 2016 Nanjiang Railway of first 100 km are selected for analysis of wind field characteristics. The results show that the wind level is relatively high and the duration is relatively long in the first 100 km wind area of Nanjiang Railway. The maximum instantaneous wind speed can reach 61.2 m/s, and the wind direction is mostly concentrated between WNW-NNW. The average wind speed, average wind direction, turbulence intensity and gust factor are analyzed by choosing the data of wind monitoring points in typical gale weather, the results show that the weather fluctuation is strong, and the high level of wind duration is long.

Growth Inhibitory Factors of Italian Ryegrass (Lolium multiflorum Lam.) after Broadcasting under Growing Rice from 2014 to 2015

The growth of Italian ryegrass (IRG) after wintering was very low in 2015 when IRG was broadcasted under growing rice in fall of 2014. To determine growth inhibitory factors of IRG, we examined the growth conditions of IRG in Nonsan region and meteorological conditions in Daejeon nearby Nonsan. Minimum temperature and maximum instantaneous wind speed on Feb. and of 2015 after wintering of IRG were , 10.7 m/s and , 9.6m/s, respectively. Air temperature was suddenly dropped due to strong wind with snow showers, which had unfavorable effect on root growth of IRG exposed at the soil surface. The minimum temperature and maximum instantaneous wind speed on Feb. , , and of 2015 were , 11.6 m/s, , 10.3 m/s, and , 7.5 m/s, respectively. The growth circumstance of IRG was not good because soil was dried due to drought continued from January. The minimum temperature and maximum instantaneous wind speed on Feb. , , and of 2015 were , 13.7 m/s, , 10.6 m/s, and , 6.8 m/s, respectively. The number of wilting of IRG was more than 59% until Mar. of 2015. IRG faced irreparable environment (low minimum temperatures and extreme instantaneous wind speeds) for 9 days from Mar. to Mar. of 2015. The main reason for the decrease of IRG productivity was collection delay of rice straw after rice harvest because there was continuous rain between Oct. and Nov. of 2014. For this reason, weakly grown IRG under rice straw was withered after wintering. IRG was withered by frost heaving, drought, and instantaneous wind speed in the spring. Furthermore, the root of IRG was damaged while growing in excess moisture in the surface of paddy soil during the winter season due to rain.

Maritime climate change research in the semicircle of the typhoon hazard area

The typhoon is one of the disaster which the man will overcomes. Till now many scientist have studied on the typhoon for a long time but it remains for a man that it will study in future. So we have interested in the typhoon and have studied on climate change by approaching of the typhoon at the shelter area of ship. The surveys are carried out during 2 days from 9th. July. to 10th. July. in 2014 by the training ship “Dong Beak” of Chonnam National University. The model of the survey was the Typhoon “NEOGURI” born at the 4th. July in 2014. The results obtained can be summarized as follows; The journey period of Typhoon Neoguri from the birth point of the typhoon to the sea area of Korea was about 6 days, and the approach velocity of the typhoon was rapidly increasing after passing through 25 degrees of the latitude. Meanwhile, considering most typhoons formed from the ocean at lower latitude take more than 7 days to reach Korea, the period of the Typhoon Neoguri was shorter than the average approaching period. Thus, it is considered that making preparation of vessels and ships for typhoon is needed from the point of over 25 degrees of the latitude. When it comes to the change of barometric pressure by a barometer had been taking place gradually till the day before the typhoon approached. The change of barometric pressure, however, was varied very sharply from the time of 12 hours before the typhoon approached to the time of 3 hours after the typhoon. The change of wind velocity by an anemometer was varied very widely for 3 hours after passing through the closest point where the typhoon was headed, but was rapidly in a state of tranquility after the 3-hour. The maximum instantaneous wind velocity was 33 knots, being the closest to the typhoon’s path, 1010hours 9th,Jul. The change of wind direction by a wind direction indicator had been shown before 9 hours when the radical change accelerated, and the trend of wind direction was general clockwise that the beginning was the east wind and it was changed as the south wind. Also, when approaching typhoon nearly, and reaching the highest point of wind velocity, the prevailing wind was the north wind. In a nut shell, regarding the change of barometer pressure, the wind velocity and the wind direction was widely varied on the basis of the approaching point of the typhoon. Therefore, the vessels or ships which are heading for sea need to figure out how to handle the situation related with typhoon by using the result of this paper. In other words, as it has been shown from the Typhoon Neoguri, we should find the sea area reducing the south wind while the dangerous semicircle and the south wind of typhoon can deal a fatal outcome to vessels and ships, and should decide the best area as a shelter of ship at typhoon area, which can protect the wind and wave by obtaining confidential information.

&lt;b&gt;Method for Evaluating Train Safety in Case of Strong Winds&lt;/b&gt;

This paper proposes a method for evaluating train running safety in strong wind conditions using the probabilities of strong wind occurrence according to wind direction. The Weibull coefficients cd and kd for 16 wind directions were calculated on the basis of data from 10-min maximum instantaneous wind velocities for each wind direction at 772 Automated Meteorological Data Acquisition System (AMeDAS) stations. Probabilities Px of the occurrence of strong winds exceeding the critical wind speeds for overturning were estimated for a train in a virtual railway section by using cd and kd calculated on the basis of the wind data observed at a windy AMeDAS station. Px values were found to vary from 6.2×10-6 to 8.6×10-5 depending on the angle between the traveling direction of the train and each wind direction. The values of Px ranged from 1.4% to 20% of the Py values, which were calculated out of consideration of strong wind occurrence according to wind direction.

The performance of small wind power generation systems on super high-rise buildings

This study was conducted on the application of small wind power generation systems to super high-rise buildings. Environmental factors considered in the application of small wind power generation systems to super high-rise buildings are the wind speed, wind direction, maximum instantaneous wind speed, air flow turbulence, and noise and vibration in the target regions and buildings. According to the results of fluid dynamics (CFD) simulations, square or rectangular shaped super high-rise buildings create turbulent air flows occurred uniformly on roofs and the sides of entire buildings, from the lowest floor to the highest. High wind speeds occurred on the sides of buildings. Few turbulent beds occurred in the case of round or triangular shaped super high-rise buildings indicating that round and triangular shapes in plan are advantageous for the application of wind power systems. Electric power generation was measured in mock-up tests. When they were installed in a row, small wind power generation systems met the standards for noise and vibration from continuous rotation indicating that they would cause little damage to buildings through their noise and vibration.

다양한 하중 조건에서 Tetrapod 소파블록의 취약부 분석

Super typhoons develop as a result of meteorological changes. In 2012, Typhoons Bolaven and Denba reached Korea. The maximum instantaneous wind speed of the typhoons reached 60 m/sec. Harbor structures including sofa block sustained damage and loss by the abnormally high waves. In Korea, tetrapod blocks were installed the most for wave dissipating. Nevertheless, a structural evaluation of the tetrapod block has not been performed. This study examined the structural mechanism and weakness part of the tetrapod block under a range of boundary conditions. The block has weakness against a tensile force because it is plain concrete. The joint part of the legs is the most vulnerable to tensile stress. The weakest part can be reduced if the joint part is reinforced as a hunch.

Spatio‐temporal analysis of possible wind generation output reductions for the Irish transmission system with a high penetration of renewables

This paper outlines a modelling methodology utilised by EirGrid, the Irish Transmission System Operator, to apportion reductions in the electricity production of wind powered generators due to a variety of security of supply issues and localised transmission congestion. Studies addressing security of supply set a limit for non-synchronous generation such as wind, to between 50% and 75% of the total system generation (demand plus exports) over the period 2011-2022. The potential impact of a possible 75% maximum instantaneous wind penetration limit on the small, synchronous and relatively-isolated Irish transmission system by 2020 is assessed. Ireland is expected to achieve the majority of its 40% renewable target in electricity from wind and there will invariably be instances when the amount of wind generation will be greater than demand. This should also be seen in the context of transmission congestion where wind generation connects on a non-firm basis prior to completion of their deep assets. Both of these issues lead to reductions in the output of wind generators and these reductions are presented in this paper, together with the description of the innovative and novel methodology used to determine these reductions. (6 pages)

Development of PSO-based robust controller for maximising wind penetration

In this paper, a new robust controller has been proposed for attaining the maximum safe instantaneous wind penetration. Particle swarm optimisation (PSO)-based algorithm has been developed to obtain the maximum safe instantaneous penetration by the optimisation of grid parameters. The developed algorithm has been tested on modified IEEE 14-bus system. The effectiveness of the proposed methodology has been shown in terms of maximum instantaneous safe wind energy penetration limit, in percentage and also maximum safe bus loading point, explicitly beyond which system drives into instability.

강원 영동지역 봄철 산불대형화 영향 기상요소 분석

In this study, we analyzed the meteorological elements, when large forest fires were occurred, The rate of precipitation was 13% of annual average precipitation. Especially, the stronger wind speed, lower humidity and rainfall than average annual record were the distinct feathers on the year when large forest fire occurred in east coast area in Kangwon region. The average, maximum and maximum instantaneous wind speed was 5.9 m/s, 11.3 m/s and 20.9 m/s when large forest fires occurred. The average, maximum and maximum instantaneous wind speed on large fire occurred were 1.8 m/s, 3.0 m/s and 6.9 m/s faster than and average wind speed when whole forest fires occurred. The results indicated that the large forest fire occurrence had a close correlation with meteorological elements.

Maximization of instantaneous wind penetration using particle swarm optimization

In this paper, a new methodology has been proposed for attaining the maximum instantaneous wind penetration by the optimization of grid control parameters. Particle Swarm Optimization (PSO) based algorithm has been developed to obtain the maximum instantaneous penetration. The developed algorithm has been tested on modified IEEE 14-bus test system. The results have shown the maximum instantaneous wind energy penetration limit in percentage and also maximum bus loading point explicitly beyond which system drives into instability. Keywords: Wind power generation, wind penetration, power system modeling, PSO

345kV 인천화력 송전선로 철탑도괴 원인분석 및 대책

345㎸ Incheon Thermal Power Plant Transmission Line Collapse Analysis and Countermeasures. The Typhoon Galmaegi which had been formed in July 15, 2008 diminished into a tropical cyclone and cooled the air above the West Sea. The cooled air colliding with the warm inland air caused a strong whirlwind at some places in the west seaside; the whirlwind battered the 345㎸ Incheon Thermal Power Plant Transmission Line to be collapsed. The resistance of transmission towers against wind pressure, one of the key elements in transmission line engineering, is designed to endure the pressure corresponding to the maximum instantaneous wind speed. Before the above accident happened, no transmission line has ever been collapsed by a whirlwind. So this paper is aimed to analyze causes that collapsed 345㎸ Incheon Thermal Power Plant transmission line and to introduce countermeasures.

AWS 데이터를 이용한 부산 해안의 바람분포 특성 해석

이 연구에서는 10년간(1997-2006년)의 기상청 AWS(Automatic Weather System) 자료를 이용하여 선박의 안전과 항만구조물 등의 안정성에 매우 중요한 부산 해안의 바람분포 특성을 분석하였다. 그리고 부산 해안의 바람분포 특성을 명확히 파악하기 위하여 해륙풍의 영향을 받지 않는 밀양의 바람분포 특성도 해석하여 비교하였다. 부산 해안의 평균풍속은 밀양보다 강하고, 부산 해안 중에서도 섬인 영도와 가덕도의 평균풍속은 일광, 해운대 및 대연의 그것보다 약 2.0배 강한 특성을 보인다. 상관분석에 의하여, 부산 해안의 월별 평균풍속은 서로 변화 경향이 매우 유사함을 확인하였다. 부산 해안의 월별 평균풍속의 최대값은 9월에 나타나는데, 이는 태풍의 영향과 밀접히 관련되어 있다. 최대 순간풍속도 섬인 영도와 가덕도에서 특히 강하고, 부산 해안의 최대순간풍속은 주로 8-9월에 그 최대값이 관측된다. 부산 해안의 풍향별 관측 횟수의 백분율을 살펴보면, 겨울은 남서풍-북북동풍이 우세하고 봄은 남서풍과 북동풍이 우세하다. 여름의 풍향 분포는 봄과 비슷하고, 가을의 풍향 분포는 겨울과 유사한 경향을 보인다. Wind velocity and wind direction are very important in the viewpoint of ship's safety and stability of port structure. The characteristics of wind distribution in the coast of Busan are analyzed for 10 years from 1997 to 2006 using AWS(Automatic Weather System) data. The characteristics of wind distribution of Miryang, is not affected by the land and sea breeze are also examined to understand clearly the characteristics of wind distribution in the coast of Busan. The mean wind velocity in the coast of Busan is stronger than that of Miryang. The mean wind velocitie at Youngdo and Gadukdo stations of Busan are stronger about 2.0 times than those at IlGwang, Haeundae and Daeyeon stations. The correlation a states show that the variation tendencies of monthly mean wind velocitie in the coast of Busan are very similar. The maximum monthly mean velocitie in the coast of Busan are recorded in September. This re ult is closely related to the influence of typhoon. The maximum instantaneous wind velocitie are also strong at Youngdo and Gadukdo stations and the peaks of maximum instantaneous wind <TEX>$velocit^9$</TEX> are observed mainly from August to September. In the coast of Busan, the SW'ly-NNE'ly wind are prevailing in the winter and the SW'ly and NE'ly wind are predomi snt in the spring. w that the vs of wind direction in the summer and athumn are similar with those in the spring and winter, respectively.