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The aim of this research is to analyse and provide realistic insight that will improve the provisions and investment in wind energy as potential source of energy for electricity generation. The data used for this assessment were obtained from the central database of Nigeria Meteorological Agency Abuja, which includes average wind speed, and direction per day of the selected location, measured at the anemometer height of 10 m, over a period of eleven years (2011-2021). The maximum monthly mean wind speed was found in January and December with a value of 4.9 m/s, and annual extractable energy was found to be 347.97KWh/M2. On average, the annual wind speed through eleven years was found in the range 3.88 - 4.00 m/s. The results revealed that, the wind resource in the study area fall within range and category 3.00 which is considered as marginal or unsuitable for higher wind power development and an excellent for water pumping and small scale electricity generation.

Background: Satellite fire radiative power (FRP) products are a potential source of wildland fire growth measurements that could be used with gridded or observed weather data to study meteorological influences on wildfire behaviour. There is little research to date examining how FRP relates to weather. Aims: The goal of this study is to explore the relationship between satellite wildland fire FRP measurements and wind speed. Methods: We examine GOES-16 FRP data from the summer of 2018 in California, comparing it with winds from the CANSAC reanalysis to understand the relationship between wind and FRP. Examination focuses on statistical distribution of the data and results of two different approaches to relating FRP and wind speed. Key results: FRP is log-normally distributed, and there are significant consequences to using conventional statistical techniques that assume normality. We propose an alternative framing of the wind speed–FRP relationship to preserve more information about the FRP distribution. Conclusions: Use of FRP data for meaningful understanding of fire–weather interactions requires attention to the nature of the FRP empirical distribution. Implications: Applying our alternative approach to relating wildland fire FRP to weather has the potential to retain much more information than conventional approaches, but requires careful examination of the FRP data in each study. Fire radiative power (FRP) is non-Gaussian, yet is often treated as such. We look at the actual distribution and how it relates to wind speed using a novel approach that preserves the distribution of FRP, rather than reducing it to a single (mean) value for a given wind speed. [ABSTRACT FROM AUTHOR]

Homogeneous vegetation is widely used in wildland fire behaviour models, although real vegetation is heterogeneous in nature and composed of different kinds of fuels and non-combustible parts. Many features of fires can arise from this heterogeneity. For land management and firefighting, creating heterogeneous fuel areas may be useful to reduce fire intensity and rate of spread (ROS), and alter fire geometry. Recently, an empirical model for fire spread in spinifex grasslands was developed and validated against experimental measurements. In this study, physics-based grassland fire behaviour simulations were conducted with varying percentages of fuel cover and alternating square and rectangular patches of burnable and non-burnable material. The environmental conditions and thermophysical properties of the grassland were kept constant throughout the simulation to separate the effects of fuel heterogeneities from other parameters. For three sets of nominal wind velocities, 3, 5.6 and 10 m s−1, we identified 'go' and 'no go' fires. Reasonable agreement between the non-dimensionalised simulated ROS and observed ROS in spinifex was found. There is a significant reduction of fire intensity, ROS, flame length, fire width and fire line length due to the heterogeneous effect of vegetation. The effect of fuel heterogeneity was studied using physics-based grassland fire simulation. Some features, such as reduction of fire intensity, fire line length, flame length and ROS may be useful in land management and firefighting. Moreover, the non-dimensional ROS of this study is comparable with an empirical spinifex grassland model. [ABSTRACT FROM AUTHOR]

This study focuses on physics-based modelling of grassfire behaviour over flat and sloped terrains through a set of field-scale simulations performed using the Wildland–urban Interface Fire Dynamics Simulator (WFDS), with varying wind speeds (12.5, 6 and 3 m s−1) and slope angles (−30° to +30°). To ensure the accuracy of this Large Eddy Simulation (LES), a sensitivity study was carried out to select the converged domain and grid sizes. Fire isochrones, locations of fire front, dynamic and quasi-steady rates of spread (RoS), and fire intensity results from the simulations are presented. Within the simulations conducted, the RoS and fire intensity were found to be higher with increasing slope angles, as well as with wind velocity. RoS comparisons are made with various empirical models. At different slope angles and driving wind velocities, different empirical quasi-steady RoS broadly match with particular dynamic maximum, minimum and averaged RoS values from this study. It appears that the ideal nature of grassfire propagation simulation and challenges related to measuring quasi-steady values in experimental studies are likely reasons for the observed differences. Additionally, for lower wind velocities, the RoS–fire intensity relationship (Byram's) deviates from linearity for greater upslopes. A physics-based study of grassfire behaviour over flat and sloped (upslope and downslope) terrains at field scale with different driving wind velocities is presented. The results of RoS of fire, isochrones, firefront locations and intensities are presented and the RoS is compared with empirical studies found in the literature. [ABSTRACT FROM AUTHOR]

The suggestion has been made within the wildland fire community that the rate of spread in the upper portion of the fire danger spectrum is largely independent of the physical fuel characteristics in certain forest ecosystem types. Our review and analysis of the relevant scientific literature on the subject suggest that fuel characteristics have a gradual diminishing effect on the rate of fire spread in forest and shrubland fuel types with increasing fire danger, with the effect not being observable under extreme fire danger conditions. Empirical-based fire spread models with multiplicative fuel functions generally do not capture this effect adequately. The implications of this outcome on fire spread modelling and fuels management are discussed. The effect of fuel complex characteristics on wildfire rates of spread appears to be non-existent in the upper end of the fire danger spectrum based on an examination of the pertinent literature. The implications of this conclusion on fire spread modelling and fuels management are discussed. [ABSTRACT FROM AUTHOR]

Spatial interpolation is a commonly used technique to simulate wind speeds in areas which are devoid of such measuring devices. In this paper authors examine the applicability and efficiency of Artificial-Neural-Network (ANN) formalism aimed at interpolating wind speeds in space domain. Additionally, the effect of the correlation between the wind speed at target site and its correlated neighboring site is also examined in the present paper. Hourly wind speed data set comprising of wind speeds recorded from April 2016 to August 2018 provided by Energy Sector Management Assistance Program of World Bank is used for the study. The study is supported by including four different wind speed measuring stations in Pakistan, namely, TandoGhulamAli, Umer Kot, Sujawal and Sanghar. Best estimates from ANN model are obtained for TandoGhulamAli (MAPE= 7.37%) andworst estimates are observed forSanghar site (MAPE= 10.61%).

Winter wheat (Triticum aestivum L.) production in the North China Plain (NCP) is threatened by wheat lodging. Therefore, enhancing plant lodging resistance by improving stem quality traits is crucial to maintaining high stable yields of winter wheat. A consecutive 7-year field experiment was conducted to study the effects of stem traits on lodging resistance and the yield of four winter wheat cultivars (Bainong 418, Aikang 58, Wenmai 6 and Zhoumai 18). The results indicated that rainfall is often accompanied by strong winds that can cause lodging in the field. Stalk bending strength and wall thickness of the second internode showed significant negative correlations with lodging index, and a higher lodging index indicated increased lodging risk, which, in turn, could seriously affect the grain yield of wheat. Significant regression relationships were observed between lodging index and population lodging resistance strength, as measured using a crop lodging resistance electronic measuring device. Statistical analysis revealed that yield components and the grain yield of Bainong 418 were higher than those of the other cultivars; there was no significant difference between Bainong 418 and Aikang 58 in lodging index, stalk bending strength or single-stalk and population lodging resistance strengths at anthesis and the middle filling stages, but the mean plant height of Bainong 418 was significantly higher than that of Aikang 58. These results provide a new and reliable method for assessing lodging resistance capacity and indicate that greater lodging resistance, as determined by simultaneously considering plant height and basal stem strength, is an important way to achieve high, stable yield in winter wheat. Lodging is a major problem affecting the high and stable yield of winter wheat in the North China Plain. In this study, the lodging resistance of wheat in the field was measured for seven consecutive years, and data regarding lodging-related traits were obtained. The results will be useful in improving the evaluation methods for wheat lodging resistance, and help our understanding of the relationship between wheat stalk characteristics and lodging resistance. [ABSTRACT FROM AUTHOR]

Grid-independent rate of spread results from a physics-based simulation are presented. Previously, such a numerical benchmark has been elusive owing to computational restrictions. The grid-converged results are used to systematically construct correlations between the rate of spread (RoS) and both wind speed and grass height, separately. The RoS obtained from the physics-based model is found to be linear with wind speed in the parameter range considered. When wind speed is varied, the physics-based model predicts faster RoS than the Mk III and V (McArthur) models (Noble et al. 1980) but slower than the CSIRO model (Cheney et al. 1998). When the grass height is varied keeping the bulk density constant, the fire front changes from a boundary layer flame mode to plume flame mode as the grass height increases. Once the fires are in plume mode, a higher grass height results in a larger heat release rate of the fire but a slower RoS. A systematic approach to grass fire modelling using a physics-based model through the establishment of the atmospheric boundary layer and grid convergence is presented. A successful reference case simulation is followed by a study of grass fire cases that tests the effects of wind speed and grass height independently. A correlation for the rate of spread as a function of grass height is proposed. [ABSTRACT FROM AUTHOR]

In this study, five numerical Weibull distribution methods, namely, the maximum likelihood method, the modified maximum likelihood method (MLM), the energy pattern factor method (EPF), the graphical method (GM), and the empirical method (EM) were explored using hourly synoptic data collected from 1985 to 2013 in the district of Maroua in Cameroon. The performance analysis revealed that the MLM was the most accurate model followed by the EPF and the GM. Furthermore, the comparison between the wind speed standard deviation predicted by the proposed models and the measured data showed that the MLM has a smaller relative error of -3.33% on average compared to -11.67% on average for the EPF and -8.86% on average for the GM. As a result, the MLM was precisely recommended to estimate the scale and shape parameters for an accurate and efficient wind energy potential evaluation.

La utilización eficaz del potencial energético del viento en una región promisoria requiere de adecuadas mediciones de su velocidad obtenidas mediante la instalación de cierto número de torres con anemómetros; estos datos se procesan y los resultados caracterizan dicho potencial. La presente investigación tiene como objetivo resolver un importante problema práctico: dada una región, determinar cuántas torres de muestreo deben ser instaladas y dónde hacerlo para que las mediciones obtenidas constituyan un sistema de datos representativo para el estudio de la velocidad del viento y del potencial energético. Se propone un procedimiento donde a partir de información previa sobre la topográfica, la rugosidad y la velocidad del viento en la región y su entorno, se pueden obtener las coordenadas de las torres mejor ubicadas sobre la base del cálculo del error probable medio de las estimaciones puntuales sobre la región.The effective use of wind energy potential in a promising region requires adequate speed measurements obtained by installing a number of towers with anemometers, these data are processed and the results characterize this potential. This research aims to solve an important practical problem: given a region, determine how many sampling towers should be installed and where to do the measurements obtained to constitute a system of representative data for the study of wind speed and energy potential. From a process where prior information on the topographical, roughness and wind speed in the region and beyond, can be obtained the coordinates best placed tower on the basis of calculating the average probable error of the point estimates of the region is proposed.

En la Parte I de este artículo fue establecido el algoritmo general de un procedimiento para el diseño del muestreo de la velocidad del viento cuyos resultados tengan la capacidad de minimizar el error probable medio durante una estimación del comportamiento espacio-temporal de la velocidad del viento. En la Parte II se describe el algoritmo de selección de puntos de muestreo y el algoritmo para el cálculo del error probable de estimación. El procedimiento para diseñarlas redes de muestreo eólico es implementado en una aplicación informática que facilita la aplicación del procedimiento a la selección de los puntos donde se ubicarán las torres anemométricas en una región promisoria del municipio Moa en la Provincia Holguín, Cuba. Los resultados obtenidos son comparados con el diseño obtenido en el año 2007 por la Empresa de Ingeniería y Proyectos de Electricidad del Ministerio de Energía y Minas de la República de Cuba.In Part I of this article was established the general algorithmof a procedure for the sampling design of the wind speed and the results have the ability to minimize the average probable error for an estimate of the conduct spatiotemporal wind speed. In Part II the selection algorithm of sampling points and the algorithm for calculating the probable error estimation is described. The procedure for the samplingdesign is implemented in an computer software that facilitates the application from the procedure to the selection of the points where theanemometer towers will be located in a promissory region of the municipality Moa in the province Holguín, Cuba. The results are compared with the design obtained in 2007 by the Empresa de Ingeniería y Proyectos de Electricidad of the Ministry of Energy and Mines of the Republic of Cuba.

The paper analyses the performance results of the recently developed short-term forecasting suit for the Latvian power system. The system load and wind power are forecasted using ANN and ARIMA models, respectively, and the forecasting accuracy is evaluated in terms of errors, mean absolute errors and mean absolute percentage errors. The investigation of influence of additional input variables on load forecasting errors is performed. The interplay of hourly loads and wind power forecasting errors is also evaluated for the Latvian power system with historical loads (the year 2011) and planned wind power capacities (the year 2023). [ABSTRACT FROM AUTHOR]

WindSat, the first polarimetric radiometer on orbit, launched in January 2003, provides the promise of passive ocean wind vector retrievals on a continuous basis, simultaneous with the retrieval of many other geophysical variables such as sea surface temperature, atmospheric water vapor, cloud liquid water, and sea ice extent and concentration. WindSat also serves as risk reduction for the upcoming National Polar-orbiting Operational Environmental Satellite System (NPOESS) Conical Scanning Microwave Imager/Sounder (CMIS). Since the dependence of microwave brightness temperatures on wind direction is small relative to that of other parameters such as wind speed, wind direction retrieval relies on increasingly accurate knowledge of the ocean surface microwave emission, which depends upon surface properties such as roughness and foam due to wave breaking. Coordinated near-surface measurements of ocean surface microwave emission and air-sea interaction parameters are needed to quantify the effects of the processes mentioned above in surface emission models to improve the accuracy of wind vector retrievals. Such coordinated observations were performed during the Fluxes, Air-Sea Interaction, and Remote Sensing (FAIRS) experiment conducted on the R/P Floating Instrument Platform (FLIP) in the northeastern Pacific Ocean during the Fall of 2000. X- and Ka-band partially polarimetric radiometers were mounted at the end of the port boom of R/P FLIP to measure ocean surface emission at incidence angles of 45°, 530, and 65°. A bore-sighted video camera recorded the fractional area of foam in the field of view of the radiometers. Air-sea interaction parameters that were measured concurrently include wind speed, friction velocity, heat fluxes, and significant wave height. The measured dependence of ocean surface emissivity on wind speed and friction velocity is in good agreement with, and extends, earlier observations and empirical models based on satellite data. Concurrent radiometric measurements and fractional area foam coverage data strengthen the possibility of retrieval of sea surface foam coverage using airborne or spaceborne radiometry. The dependence of emissivity on atmospheric stability is shown to be much smaller than the dependence of emissivity on wind speed. Analysis of emissivity dependence on atmospheric stability alone was inconclusive, due to the variation in atmospheric stability with wind speed. The effect of long-wave incidence angle modulation on sea surface emissivity for near-surface measurements was found to be negligible when emissivity measurements were averaged over tens to hundreds of long waves. [ABSTRACT FROM AUTHOR]

Database-assisted design (DAD) for wind results in structures with reduced material consumption and failure risks, i.e., in improved safety and sustainability. The paper presents a DAD-compatible probabilistic procedure for estimating: (1) Wind effects corresponding to any mean recurrence interval of the wind speeds, and (2) wind-load factors. Unlike the ASCE 7 Standard and earlier structural reliability estimates, the procedure accounts for the inherent randomness in the estimation of peaks and for relevant wind-related knowledge uncertainties. On the basis of a selection of uncertainty parameters believed to be reasonable, it is concluded that: (1) The extreme wind speed distribution type significantly affects the estimates of the load factors. Our estimates, based on the Extreme Value Type III Reverse Weibull distribution, yield load factors consistent with values specified in the ASCE 7 Standard—in contrast to estimates published in the 1980’s. (2) The variability of the ratio between wind speeds averaged over different time intervals can significantly affect the estimated wind-load factor. (3) An increase in size of the extreme wind data set from, say, 30 to 50 years, has a marginal effect on load factor estimates. (4) For low-rise buildings in open terrain, wind-load factors are typically affected weakly by even large uncertainties with respect to terrain roughness length. Additional research on the effect of terrain roughness uncertainties for buildings in built-up terrain may require an expansion of the aerodynamic databases currently available. It is noted that consideration of uncertainties in isolation, as commonly performed by some analysts and wind tunnel operators, especially for peak effects estimation, can be misleading; for structural applications, uncertainties need to be considered collectively. [ABSTRACT FROM AUTHOR]

The global availability of synthetic aperture radar (SAR) wave mode data from the European Remote Sensing (ERS) satellites ERS-1 and ERS-2, as well as ENVISAT, allows for the investigation of the wind field over the ocean on a global and continuous basis. For this purpose, 27 days of ERS-2 SAR wave mode data were processed, representing a total of 34 310 imagettes of size 10 km x 5 km, available every 200 km along the satellite track. In this paper, two methods for retrieving wind speeds from SAR imagettes are presented and validated, showing the applicability of ENVISAT alike SAR wave mode data for global ocean wind retrieval. The first method is based on the well-tested empirical C-band scatterometer (SCAT) models, which describe the dependency of the normalized radar cross section (NRCS) on wind speed and direction. To apply C-band models to SAR data, the NRCS needs to be accurately calibrated. This is performed by a new efficient method utilizing a subset of colocated measurements from ERS-2 SCAT and model winds from the European Centre for Medium-Range Weather Forecast (ECMWF). SAR wind speeds are computed from the calibrated imagettes and compared to the entire set of colocated ERS-2 SCAT and ECMWF model data. Comparison to ERS-2 SCAT winds result in a correlation of 0.95 with a bias of -0.01 ms[SUP-1] and an rms error of 1.0 ms[SUP-1]. The second approach is based on neural networks (NNs), which allow the retrieval of wind speeds from uncalibrated SAR imagettes. NNs are trained using the mean intensity of ERS-2 SAR imagettes and colocated wind data from the ERS-2 SCAT and ECMWF model data. Validation of the NN-retrieved SAR wind speeds to ERS-2 SCAT and ECMWF model wind data result in a correlation of 0.96 with a bias of -0.04 ms[SUP-1] and an rms error of 0.93 ms[SUP-1]. [ABSTRACT FROM AUTHOR]

The experiments and simulations reported in this paper show that, for stomata sensitive to both CO2 and water vapour concentrations, responses of stomatal conductance (gsw) to boundary layer thickness have two components, one resulting from changes in intercellular CO2 concentration (χic) and another from changes in leaf surface water vapour saturation deficit (Dsw). The experiments and simulations also show that the boundary layer conductance (gbw) can significantly alter the apparent response of gsw) to ambient air CO2 mole fraction (χac) and water vapour mole fraction (χ aw). Because of the feedback loop involved the responses of gsw) for χac) and χaw) each include responses to both χic) and Dsw), The boundary layer alters the state of the variables sensed by the guard cells-i.e. χic) and Dsw)-and so it is a source of feedback, Thus, when scaling up from responses of stomata to the response of gsw) for a whole leaf, the effect of the boundary layer must be considered. The results indicate that, for given responses of gsw) to χic)and Dsw), the apparent responses of gsw) to Daw and χac) depend on the size of the leaf and wind speed, showing that this effect of the boundary layer should be considered when comparing data measured under different conditions, or with different methods. [ABSTRACT FROM AUTHOR]