Mean Wind Velocity Research Articles

MP03-18 DO WEATHER PARAMETERS AFFECT THE INCIDENCE OF RENAL COLIC IN A PREDOMINANTLY WARM COUNTRY? A MULTICENTER ECOLOGICAL STUDY

INTRODUCTION AND OBJECTIVE:The etiology of kidney stones is multi-factorial, with observed geographic and seasonal differences affecting the rate of stone formation. Multiple studies have reported ...

Statistical modeling of phenology in Bavaria based on past and future meteorological information

Plant phenology is well known to be affected by meteorology. Observed changes in the occurrence of phenological phases are commonly considered some of the most obvious effects of climate change. However, current climate models lack a representation of vegetation suitable for studying future changes in phenology itself. This study presents a statistical-dynamical modeling approach for Bavaria in southern Germany, using over 13,000 paired samples of phenological and meteorological data for analyses and climate change scenarios provided by a state-of-the-art regional climate model (RCM). Anomalies of several meteorological variables were used as predictors and phenological anomalies of the flowering date of the test plant Forsythia suspensa as predictand. Several cross-validated prediction models using various numbers and differently constructed predictors were developed, compared, and evaluated via bootstrapping. As our approach needs a small set of meteorological observations per phenological station, it allows for reliable parameter estimation and an easy transfer to other regions. The most robust and successful model comprises predictors based on mean temperature, precipitation, wind velocity, and snow depth. Its average coefficient of determination and root mean square error (RMSE) per station are 60% and ± 8.6 days, respectively. However, the prediction error strongly differs among stations. When transferred to other indicator plants, this method achieves a comparable level of predictive accuracy. Its application to two climate change scenarios reveals distinct changes for various plants and regions. The flowering date is simulated to occur between 5 and 25 days earlier at the end of the twenty-first century compared to the phenology of the reference period (1961–1990).

Review of models for predicting wind characteristics behind windbreaks

This paper reviews 5 existing models for predicting wind characteristics, namely the mean wind velocity and turbulence intensity, in the sheltered area of single or multi-row windbreaks. The paper briefly presents the mechanism of wind flow around windbreaks and then describes 5 models that predict the profiles of mean wind speed in the lee of windbreaks. These 5 models are the Schwartz model, the Engineering Sciences Data Unit (ESDU) model, the Středová model, the Hong model and the He model. The ESDU model can be used to estimate the mean horizontal wind speed profile and the turbulence intensity whilst the other 4 models are only capable of predicting the mean horizontal wind speed profile. By using existing wind speed datasets obtained from field measurements, laboratory tests and numerical simulations, the 5 models are assessed for their accuracy. It is found that the ESDU model is the most accurate for predicting the mean horizontal wind speed for flow regions behind a single windbreak. Behind multi-row windbreaks, the He model is found to provide the most accurate estimates of horizontal wind speed. In the case of predicting turbulence intensity, the ESDU model provides acceptable predictions, but unfortunately very limited data exist to validate these predictions. While the performance of these models is adequate, there is still much work to be done to further develop them and to address their current limitations.

Comparison of turbulence measurements by a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar

Abstract. Accurate measurements of turbulence statistics in the atmosphere are important for eddy-covariance measurements, wind energy research, and the validation of atmospheric numerical models. Sonic anemometers are widely used for these applications. However, these instruments are prone to probe-induced flow distortion effects, and the magnitude of the resulting errors has been debated due to the lack of an absolute reference instrument under field conditions. Here, we present the results of an intercomparison experiment between a CSAT3B sonic anemometer and a high-resolution bistatic Doppler lidar, which is inherently free of any flow distortion. This novel remote sensing instrument has otherwise very similar spatial and temporal sampling characteristics to the sonic anemometer and hence served as a reference for this comparison. The presented measurements were carried out over flat homogeneous terrain at a measurement height of 30 m. We provide a comparative statistical analysis of the resulting mean wind velocities, the standard deviations of the vertical wind speed and the friction velocity and investigate the reasons for the observed deviations based on the turbulence spectra and co-spectra. Our results show an agreement of the mean wind velocity measurements and the standard deviations of the vertical wind speed with a comparability of 0.082 and 0.020 m s−1, respectively. Biases for these two quantities were 0.003 and 0.012 m s−1, respectively. Slightly larger differences were observed for friction velocity. Analysis of the corresponding co-spectra showed that the CSAT3B underestimates this quantity systematically by about 3 % on average as a result of co-spectral losses in the frequency range between 0.1 and 5 s−1. We also found that an angle-of-attack-dependent transducer-shadowing correction does not improve the agreement between the CSAT3B and the Physikalisch-Technische Bundesanstalt (PTB) lidar effectively.

Nonlinear Aeroelastic in-Plane Behavior of Suspension Bridges under Steady Wind Flow

The nonlinear aeroelastic behavior of suspension bridges, undergoing dynamical in-plain instability (galloping), is analyzed. A nonlinear continuous model of bridge is formulated, made of a visco-elastic beam and a parabolic cable, connected each other by axially rigid suspenders, continuously distributed. The structure is loaded by a uniform wind flow which acts normally to the bridge plane. Both external and internal damping are accounted for the structure, according to the Kelvin-Voigt rheological model. The nonlinear aeroelastic effects are evaluated via the quasi-static theory, while structural nonlinearities are not taken into account. First, the free dynamics of the undamped bridge are addressed, and the natural modes determined. Then, the nonlinear equations ruling the dynamics of the aeroelastic system, close to the bifurcation point, are tackled by the Multiple Scale Method. This is directly applied to the partial differential equations, and provides the finite-dimensional bifurcation equations. From these latter, the limit-cycle amplitude and its stability are evaluated as function of the mean wind velocity. A case study of suspension bridge is analyzed.

Meteorological Factors and Swine Erysipelas Transmission in Southern China

Abstract Swine erysipelas (SE) is one of the best-known and most serious diseases that affect domestic pigs, which is caused by Erysipelothrix rhusiopathiae. It is endemic in Nanning and has been circulating for decades, causing considerable economic losses. The aim of this study was to investigate the effect of meteorological-related variations on the epidemiology of swine erysipelas in Nanning City, a subtropical city of China. Data on monthly counts of reported swine erysipelas and climate data in Nanning are provided by the authorities over the period from 2006 to 2015. Cross-correlation analysis was applied to identify the lag effects of meteorological variables. A zero-inflated negative binomial (ZINB) regression model was used to evaluate the independent contribution of meteorological factors to SE transmission. After controlling seasonality, autocorrelation and lag effects, the results of the model indicated that Southern Oscillation Index (SOI) has a positive effect on SE transmission. Moreover, there is a positive correlation between monthly mean maximum temperature and relative humidity at 0-1 month lag and the number of cases. Furthermore, there is a positive association between the number of SE incidences and precipitation, with a lagged effect of 2 months. In contrast, monthly mean wind velocity negatively correlated with SE of the current month. These findings indicate that meteorological variables may play a significant role in SE transmission in southern China. Finally, more public health actions should be taken to prevent and control the increase of SE disease with consideration of local weather variations.

Strong Wind Characteristics and Buffeting Response of a Cable-Stayed Bridge under Construction.

This study carries out a detailed full-scale investigation on the strong wind characteristics at a cable-stayed bridge site and associated buffeting response of the bridge structure during construction, using a field monitoring system. It is found that the wind turbulence parameters during the typhoon and monsoon conditions share a considerable amount of similarity, and they can be described as the input turbulence parameters for the current wind-induced vibration theory. While the longitudinal turbulence integral scales are consistent with those in regional structural codes, the turbulence intensities and gust factors are less than the recommended values. The wind spectra obtained via the field measurements can be well approximated by the von Karman spectra. For the buffeting response of the bridge under strong winds, its vertical acceleration responses at the extreme single-cantilever state are significantly larger than those in the horizontal direction and the increasing tendencies with mean wind velocities are also different from each other. The identified frequencies of the bridge are utilized to validate its finite element model (FEM), and these field-measurement acceleration results are compared with those from the FEM-based numerical buffeting analysis with measured turbulence parameters.

Investigations of flow field around two-dimensional simplified models with wind tunnel experiments

The effect of topographic features on wind velocity and turbulence intensity was evaluated by conducting wind tunnel experiments with Particle Image Velocimetry (PIV) system. In this study, to simulate the natural wind characteristics, the active turbulence grids and boundary layer generation frame were installed in the wind tunnel. The mean wind velocity, the velocity vector diagram and the turbulence intensity around the two-dimensional single simplified models were investigated. As a result, the flow was separated at the simplified model tip in all cases of models, and the countercurrent flow field was generated at the downstream side. Moreover, the clockwise circulation flow also moved to the upstream side in the case of large radius R. RX was followed by the name given the radius value of X. For the mainstream turbulence intensity, the ranges of high turbulence intensity were z/H < 2.8 for R1 model, z/H < 2.6 for R3 model, z/H < 2.5 for R6 model, z/H < 2.4 for R11 model, z/H < 2.2 for R20 model, z/H < 2.0 for R23 model, z/H < 1.9 for R25 model in the vertical direction. The quantitative measurement results of this paper provided a database for the validation of the wind velocity distributions of atmospheric turbulent flow in the hill and mountain regions.

Application of non-conventional soft computing approaches for estimation of reference evapotranspiration in various climatic regions

Evapotranspiration (ET) is a fundamental element in the hydrological cycle and plays a vital role in simulating hydrological effects of climate change. Accurate estimation of reference evapotranspiration (ETo) plays a significant role in the field of hydrometeorology and agrometeorology. There are many direct or indirect methods that are employed for estimation of ETo. Furthermore, soft computing approaches are also used to solve complex problems of estimation in various disciplines. The application of the soft computing techniques for estimating evapotranspiration has only been limited to few approaches including artificial neural network, fuzzy logic, and genetic algorithm. This study is conducted to apply non-conventional soft computing approaches for estimating ETo which include single decision tree (SDT), tree boost (TB), and decision tree forest (DTF). Monthly meteorological data spanning over 30 years (1987 to 2016) for six different cities located in arid, semi-arid, and humid regions of Pakistan is used for the estimation of ETo in this study. Seventeen input combinations comprising of various climatic parameters were developed to evaluate the impact of different parameters. A total of 306 models were developed using the SDT, TB, and DTF approaches for all six selected cities of Pakistan. The results of the developed models are then compared with ETo calculated by the standard method of modified Penmen equation. The TB modeling technique is found to perform best for various cities located in different climatic zones of Pakistan. Only two climatic parameters, the mean temperature and wind velocity, are found to be sufficient for efficient ETo prediction. To further validate the results, the outcome of the study was applied on some other climatic regions located in the USA, New Zealand, and China. Finally, it is concluded that these non-conventional approaches can also be considered superior alternatives to the available methods of estimating ETo.

Nonlinear aeroelastic behavior of a base-isolated beam under steady wind flow

A homogeneous continuous visco-elastic shear-beam, describing the dynamics of base-isolated tall buildings exposed to a uniformly distributed steady wind flow, is studied. The shear beam is constrained at the bottom end by a nonlinear visco-elastic device and free at the top end. The aeroelastic effects, responsible for self-excitation, are evaluated via the quasi-static theory. The occurrence of Hopf bifurcation is detected. Critical and post-critical behavior is analyzed by applying a perturbation scheme. The critical wind velocity and the associated complex galloping mode are found. The steady value of the oscillation amplitude on the stable limit-cycle and its stability are evaluated as function of the mean wind velocity. The mechanical performances of the structure are investigated in according to the effectiveness of the visco-elastic isolation system. A passive controller is proposed to increase the galloping wind velocity and to reduce the amplitude of the limit-cycle.

A Wind Tunnel Study on the Correlation between Urban Space Quantification and Pedestrian–Level Ventilation

Correlation research on urban space and pedestrian–level wind (PLW) environments is helpful for improving the wind comfort in complex urban space. It could also be significant for building and urban design. Correlation research is usually carried out in a space with clear urban spatial characteristics, so it is necessary to define the space first. In this paper, a typical urban area in Nanjing, China, is selected as the research object, and a spatial partition method is used to divide the real complex urban space into subspaces. The urban spatial characteristics of such subspaces are quantified using three urban spatial indices: openness (O), area (A), and shape (S). By comparing the quantitative results, 24 (12 pairs) subspaces with prominent urban spatial indices are selected as the correlation research cases. The 24 subspaces also provide a reference for the layout of the measurement points in a wind tunnel experiment. This is a new arrangement for locating the measurement points of a wind tunnel for correlation research. In the experiment, 45 measurement points are located, and the mean wind velocity of four different wind directions at 45 measurement points is experimented. The results clearly show that, when the experimental conditions are the same, the changes of mean wind velocity ratio (UR) of 24 (12pairs) subspaces under the four experimental wind directions are close. The URs of the subspaces are not significantly affected by the wind direction, which is affected more by the subspaces’ spatial characteristics. When making the correlation analysis between mean wind speed ratio and spatial characteristics’ indices, a direct numerical comparison was not able to find a correlation. By comparing the difference values of mean wind speed (△UR) and indices between each pair of subspaces, the correlation between UR and openness of subspaces were found. Limited by spatial partition method, the correlation between UR and the other indices was not obvious.

Experimental determination of the two-dimensional aerodynamic admittance of typical bridge decks

In this paper, the two-dimensional lift, drag and pitching moment aerodynamic admittances of three typical bridge deck sections, including a streamlined box section, an edge section and a truss section are identified by wind tunnel tests using a statistical identification approach and high-frequency dynamic balance measurement technique. An empirical formula for determining the two-dimensional aerodynamic admittance is proposed and compared with the commonly used Sears function and Davenport function. The results show that the two-dimensional lift and moment aerodynamic admittances for the three types of bridge decks are larger than Sears’ function in the concerned wavenumber range of the buffeting analysis. This indicates that the Sears function may underestimate the vertical and torsional buffeting response of prototype long-span bridges. The two-dimensional drag aerodynamic admittance of the truss section corresponds strongly with Davenport’s function, which verifies the reasonableness of Davenport’s function that was originally developed for the two-dimensional drag aerodynamic admittance of open lattice structures. Furthermore, it was found that the two-dimensional aerodynamic admittance is insensitive to the mean wind velocity. The effect of wind attack angle on the two-dimensional aerodynamic admittance of bridge decks cannot be neglected.

Weibull and Generalized Extreme Value Distributions for Wind Speed Data Analysis of Some Locations in India

Wind velocity data modeling plays a crucial role for the estimation of wind load and wind energy. Apart from these, the same modeling must also be used in the load cycle analysis of fatigue failure in slender structures to address periodic vortex shedding. Most authors fitted the entire available range of wind velocities of various locations using Weibull models. However, they did not check the validity of the model in describing the range of extreme wind velocity. In this work, the validity of Weibull models for describing parent as well as extreme hourly mean wind velocity data for four places on the east coast of India has been checked. While it predicts lower wind speeds accurately, the Weibull model has been found to become inappropriate for describing wind velocity in the range of extremes, i.e., above a certain threshold value. Therefore, this article focuses on the techniques of determining a limiting wind velocity beyond which the Weibull distribution is rendered unsuitable. In the range where the Weibull distribution fails, various extreme value distributions, such as Gumbel, Fréchet and reverse Weibull distributions have been compared, thereby determining the best estimator for each location.

Effects of climate factors on hemorrhagic fever with renal syndrome in Changchun, 2013 to 2017.

Hemorrhagic fever with renal syndrome (HFRS) is a rodent-borne disease caused by hantaviruses (HVs). Climate factors have a significant impact on the transmission of HFRS. Here, we characterized the dynamic temporal trend of HFRS and identified the roles of climate factors in its transmission in Changchun, China.Surveillance data of HFRS cases and data on related environmental variables from 2013 to 2017 were collected. A principal components regression (PCR) model was used to quantify the relationship between climate factors and transmission of HFRS.During 2013 to 2017, a distinctly declining temporal trend of annual HFRS incidence was identified. Four principal components were extracted, with a cumulative contribution rate of 89.282%. The association between HFRS epidemics and climate factors was better explained by the PCR model (F = 10.050, P <.001, adjusted R2 = 0.456) than by the general multiple regression model (F = 2.748, P <.005, adjusted R2 = 0.397).The monthly trends of HFRS were positively correlated with the mean wind velocity but negatively correlated with the mean temperature, relative humidity, sunshine duration, and accumulative precipitation of the different previous months. The study results may be useful for the development of HFRS preventive initiatives that are customized for Changchun regarding specific climate environments.

Field measurement of near-surface typhoon characteristics using a smart monitoring system on a long-span arch bridge site

During landfall of Typhoon Haikui in Eastern China in 2012, ground level wind data were recorded using a smart monitoring system installed on JiuBao Bridge in Hangzhou, China. This article documents the mean flow and turbulence characteristics from data recorded during the storm. The results show that both turbulence intensity and gust factor decrease with the increase in the mean wind velocity. However, as the mean wind velocity increases, this trend gradually attenuates. The peak factor distribution with gust averaging time duration derived with the Typhoon Haikui data agrees well with the Durst curve. However, the longitudinal gust factor derived from the typhoon wind-speed record in this study is higher compared with the curves proposed by Durst and Krayer-Marshall. Analyses of the gust factor distribution with the turbulence intensity during the passage of the storm reveal a similarity to the empirical curves of Ishizaki and Choi. Results show that the relationship between lateral turbulence and gust factors can be well represented by a quadratic polynomial. Turbulence scale increased with mean wind velocity. The values of autocorrelation coefficients in longitudinal direction are larger than those in lateral direction. There has no obvious dependency of cross-correlation coefficients with mean wind velocity. In general, the wind characteristics in this study are shown to be very similar to those of winds under normal circumstance.

Optimal Design of Building for Urban Wind Energy Utilization

The article deals with numerical and experimental investigation of wind flow in roof area and optimal design of input parts, where is possible to use IRWES system (Integrated Roof Wind Energy System). Orientation of some high-rise objects is suitable for using wind power. In the first phase, the selected building was investigated using CFD simulation for creating space for three small wind turbines in the area of two technical floors. By using 3D print technology, model of the structure in scale 1:300 with rough façade was created. Experimental measurements were performed in Boundary Layer Wind Tunnel in Bratislava. Measurements were made for 3 reference wind speeds, which fulfilled flow similarity of prototype and model. We have compared the results of the numerical simulations and experimental measurements and obtained information on the average wind speeds at the VAWT site. Comparison of the mean wind velocity and external wind pressure coefficient obtained by CFD simulation and experimental measurements showed a good match. Considering the annual average wind speed at about 100m above sea level, we compared the wind acceleration at the turbine site.

Effect of meteorological factors on scarlet fever incidence in Guangzhou City, Southern China, 2006–2017

ObjectiveTo explore the relationship between meteorological factors and scarlet fever incidence from 2006 to 2017 in Guangzhou, the largest subtropical city of Southern China, and assist public health prevention and control measures. MethodsData for weekly scarlet fever incidence and meteorological variables from 2006 to 2017 in Guangzhou were collected from the National Notifiable Disease Report System (NNDRS) and the Guangzhou Meteorological Bureau (GZMB). Distributed lag nonlinear models (DLNMs) were conducted to estimate the effect of meteorological factors on weekly scarlet fever incidence in Guangzhou. ResultsWe observed nonlinear effects of temperature, relative humidity, and wind velocity. The risk was the highest when the weekly mean temperature was 31 °C during lag week 14, yielding a relative risk (RR) of 1.48 (95% CI: 1.01–2.17). When relative humidity was 43.5% during lag week 0, the RR was 1.49 (95% CI: 1.04–2.12); the highest RR (1.55, 95% CI: 1.20–1.99) was reached when relative humidity was 93.5% during lag week 20. When wind velocity was 4.4 m/s during lag week 13, the RR was highest at 3.41 (95% CI: 1.57–7.44). Positive correlations were observed among weekly temperature ranges and atmospheric pressure with scarlet fever incidence, while a negative correlation was detected with aggregate rainfall. The cumulative extreme effect of meteorological variables on scarlet fever incidence was statistically significant, except for the high effect of wind velocity. ConclusionWeekly mean temperature, relative humidity, and wind velocity had double-trough effects on scarlet fever incidence; high weekly temperature range, high atmospheric pressure, and low aggregate rainfall were risk factors for scarlet fever morbidity. Our findings provided preliminary, but fundamental, information that may be useful for a better understanding of epidemic trends of scarlet fever and for developing an early warning system. Laboratory surveillance for scarlet fever should be strengthened in the future.

Patterns of change of mean wind velocity maximums in Krasnodar Krai from the beginning of anemometric measurements

Paper addresses maximum annual values of mean wind velocity in all plain and piedmont regions of Krasnodar Krai, which were used as the basis for establishing wind loads on buildings in local code SNKK “Loads and Actions. Snow Loads and Wind Actions”. Research employs time series of anemometric measurements of wind velocities from the beginning of 1970s to 2012 extended by 13 years as compared to the time series used for developing this code. Inversion criterion was employed for assessing the significance of the linear trend of wind velocity maximums. Assessment made for the data of 29 meteorological stations showed that significant trend of increase of wind velocity with the high level of statistical certainty is present only in two cases. In half of the rest cases trend is descending, in another half trend is statistically insignificant as well as mostly descending. Combined analysis of time series of vane and anemometric mean wind velocity measurements over 1945 – 2012 demonstrated one period of significant increase of wind velocities in 1966 – 1977 and sustained decrease of these velocities in 1979 – 2012. It is shown that the database of 10 minutes mean wind velocities used for development of SNKK in 2000 does not underestimate wind pressure as compared to the values observed up to the present time.

A Wind Climate Dynamic Modeling and Control Using Weibull and Extreme Value Distribution System

The dynamics of wind velocity data modeling plays a crucial role for the estimation of wind load and wind energy. Apart from these, the same modeling must also be used in the load cycle analysis of fatigue failure in slender structures to address periodic vortex shedding. Most authors fitted wind velocities of various locations using Weibull model. However, they did not check the validity of the model in describing the range of extreme wind velocity, which is not clear from the usual graphical representation. In this work, the validity of Weibull model for describing parent as well as extreme hourly mean wind velocity data for four places on the east coast of India has been checked; Weibull model has been found to become inappropriate for describing wind velocity in the range of extremes.

A Study on Shipments of Swimming Crab Using Negative Binomial Regression Model

본 연구는 해양기상관측자료인 평균 풍속, 평균 기압, 평균 상대습도, 평균 기온, 평균 수온, 평균 최대파고, 평균 유의파고, 최고 유의파고, 최고 최대파고, 평균 파주기, 최고 파주기 등의 요인들이 꽃게의 출하건수에 미치는 영향을 음이항 회귀모형을 통해 확인하고 모형적합을 시도하였다. 염분과 수온이 갑각류의 성숙 및 산란에 영향을 미치며, 특히 수온은 성장에 관여하는 대사 작용에 영향을 끼친다고 알려져 있고 최근 지구온난화로 인해, 얼음이 녹으면서 바다의 유의, 최대, 평균파고와 파주기, 그리고 수온까지 영향을 미치고 있어 꽃게 출하건수를 예측하는데 있어 중요한 변수라고 생각할 수 있다. 분석결과 꽃게의 출하건수에 영향을 주는 요인은 평균 풍속, 평균 기압, 평균 상대습도, 평균 해수온도, 최대 파고, 평균 파주기, 최대 파주기로 결정되었다. 꽃게의 출하건수는 평균 풍속, 평균 기압, 평균 상대습도, 평균 해수온도, 평균 파주기가 높을수록 증가하는 경향을 보이고 있고, 최대 파고, 최대 파주기가 낮을수록 꽃게의 출하건수는 증가하는 경향을 보이고 있었다.The purpose of this paper is to analyse the effect of ocean weather factors on shipments of swimming crab. We use the data of data portal and ocean weather factors (mean wind velocity, mean atmospheric pressure, mean relative humidity, mean air temperature, mean water temperature, mean maximum wave height, mean significant wave height, maximum significant wave height, maximum wave height, mean wave period, maximum wave period). We did statistical analysis using Poisson regression analysis and negative binomial regression analysis. As the result of study, important factors influential in the shipments of swimming crab turn out to be mean wind velocity, mean atmospheric pressure, mean relative humidity, mean water temperature, maximum wave height, mean wave period and maximum wave period. the shipments of swimming crab increases as mean wind velocity, mean atmospheric pressure, mean relative humidity, mean water temperature increases or mean wave period increase. However, as maximum wave height, maximum wave period decreases, the shipment of swimming crab increases.