Wind speed

About: Wind speed is a research topic. Over the lifetime, 48350 publications have been published within this topic receiving 830486 citations.

WorldClim 2: new 1-km spatial resolution climate surfaces for global land areas

Abstract: We created a new dataset of spatially interpolated monthly climate data for global land areas at a very high spatial resolution (approximately 1 km2). We included monthly temperature (minimum, maximum and average), precipitation, solar radiation, vapour pressure and wind speed, aggregated across a target temporal range of 1970–2000, using data from between 9000 and 60 000 weather stations. Weather station data were interpolated using thin-plate splines with covariates including elevation, distance to the coast and three satellite-derived covariates: maximum and minimum land surface temperature as well as cloud cover, obtained with the MODIS satellite platform. Interpolation was done for 23 regions of varying size depending on station density. Satellite data improved prediction accuracy for temperature variables 5–15% (0.07–0.17 °C), particularly for areas with a low station density, although prediction error remained high in such regions for all climate variables. Contributions of satellite covariates were mostly negligible for the other variables, although their importance varied by region. In contrast to the common approach to use a single model formulation for the entire world, we constructed the final product by selecting the best performing model for each region and variable. Global cross-validation correlations were ≥ 0.99 for temperature and humidity, 0.86 for precipitation and 0.76 for wind speed. The fact that most of our climate surface estimates were only marginally improved by use of satellite covariates highlights the importance having a dense, high-quality network of climate station data.

Relationship between wind speed and gas exchange over the ocean

Abstract: Relationships between wind speed and gas transfer, combined with knowledge of the partial pressure difference of CO2 across the air-sea interface are frequently used to determine the CO2 flux between the ocean and the atmosphere. Little attention has been paid to the influence of variability in wind speed on the calculated gas transfer velocities and the possibility of chemical enhancement of CO2 exchange at low wind speeds over the ocean. The effect of these parameters is illustrated using a quadratic dependence of gas exchange on wind speed which is fit through gas transfer velocities over the ocean determined by the natural-14C disequilibrium and the bomb-14C inventory methods. Some of the variability between different data sets can be accounted for by the suggested mechanisms, but much of the variation appears due to other causes. Possible causes for the large difference between two frequently used relationships between gas transfer and wind speed are discussed. To determine fluxes of gases other than CO2 across the air-water interface, the relevant expressions for gas transfer, and the temperature and salinity dependence of the Schmidt number and solubility of several gases of environmental interest are included in an appendix.

Wind Energy Handbook

Abstract: As environmental concerns have focused attention on the generation of electricity from clean and renewable sources wind energy has become the world's fastest growing energy source. The Wind Energy Handbook draws on the authors' collective industrial and academic experience to highlight the interdisciplinary nature of wind energy research and provide a comprehensive treatment of wind energy for electricity generation. Features include: * An authoritative overview of wind turbine technology and wind farm design and development * In-depth examination of the aerodynamics and performance of land-based horizontal axis wind turbines * A survey of alternative machine architectures and an introduction to the design of the key components * Description of the wind resource in terms of wind speed frequency distribution and the structure of turbulence * Coverage of site wind speed prediction techniques * Discussions of wind farm siting constraints and the assessment of environmental impact * The integration of wind farms into the electrical power system, including power quality and system stability * Functions of wind turbine controllers and design and analysis techniques With coverage ranging from practical concerns about component design to the economic importance of sustainable power sources, the Wind Energy Handbook will be an asset to engineers, turbine designers, wind energy consultants and graduate engineering students.

Open Ocean Momentum Flux Measurements in Moderate to Strong Winds

Abstract: Measurements of the momentum flux were made by the Reynolds flux and dissipation methods on a deep water stable tower operated by the Bedford Institute of Oceanography, A modified Gill propeller-vane anemometer was used to measure the velocity. Drag coefficients from 196 Reynolds flux measurements agree well with those reported in Smith (1980) based on independent observations at the same site. Based on 192 runs, a comparison of the dissipation and Reynolds flux results shows excellent agreement on average, for wind speeds from 4 to 20 m s−1. The much more extensive dissipation data set (1086 h from the tower and 505 h from the weathership PAPA, CCGS Quadra) was used to investigate the dependence of the drag coefficient on wind speed, fetch and stability. The drag coefficient reduced to 10 m height and neutral conditions (CDN), is independent of stability and fetch (for fetch/height ≳800) but increases with wind speed above 10 m s−1. Some time series of the momentum flux and drag coefficient are ...

An Overview of the HYSPLIT_4 Modelling System for Trajectories, Dispersion, and Deposition

Abstract: The HYSPLIT_4 (HYbrid Single-Particle Lagrangian Integrated Trajectory) model is designed for quick response to atmospheric emergencies, diagnostic case studies, or climatological analyses using previously gridded meteorological data. Calculations may be performed sequentially on multiple meteorological grids, going from fine to coarse resolution using either archive or forecast data fields. Air concentration calculations associate the mass of the pollutant species with the release of either puffs, particles, or a combination of both. The dispersion rate is calculated from the vertical diffusivity profile, wind shear, and horizontal deformation of the wind field. Air concentrations are calculated at a specific grid point for puffs and as cell-average concentrations for particles. The model results are evaluated against ACE balloon trajectories, air concentrations from the ANATEX tracer experiment, radiological deposition from the Chernobyl accident, and satellite photographs of the Rabaul volcanic eruption. One common feature of the model results was their sensitivity to the vertical atmospheric structure; trajectories in terms of their height when near ground-level due to the strong gradients of wind speed and direction, air concentrations with respect to the rate of vertical mixing, and deposition as a result of the vertical distribution of the pollutant.