WorldWideScience

Sample records for hub-height wind climatologies

  1. On the Predictability of Hub Height Winds

    DEFF Research Database (Denmark)

    Draxl, Caroline

    Wind energy is a major source of power in over 70 countries across the world, and the worldwide share of wind energy in electricity consumption is growing. The introduction of signicant amounts of wind energy into power systems makes accurate wind forecasting a crucial element of modern electrical...... grids. These systems require forecasts with temporal scales of tens of minutes to a few days in advance at wind farm locations. Traditionally these forecasts predict the wind at turbine hub heights; this information is then converted by transmission system operators and energy companies into predictions...... of power output at wind farms. Since the power available in the wind is proportional to the wind speed cubed, even small wind forecast errors result in large power prediction errors. Accurate wind forecasts are worth billions of dollars annually; forecast improvements will result in reduced costs...

  2. Bringing satellite winds to hub-height

    DEFF Research Database (Denmark)

    Badger, Merete; Pena Diaz, Alfredo; Bredesen, Rolv Erlend

    2012-01-01

    Satellite observations of the ocean surface can provide detailed information about the spatial wind variability over large areas. This is very valuable for the mapping of wind resources offshore where other measurements are costly and sparse. Satellite sensors operating at microwave frequencies...... measure the amount of radar backscatter from the sea surface, which is a function of the instant wind speed, wind direction, and satellite viewing geometry. A major limitation related to wind retrievals from satellite observations is that existing empirical model functions relate the radar backscatter...

  3. Bringing satellite winds to hub-height

    DEFF Research Database (Denmark)

    Badger, Merete; Pena Diaz, Alfredo; Bredesen, Rolv Erlend

    2012-01-01

    Satellite observations of the ocean surface can provide detailed information about the spatial wind variability over large areas. This is very valuable for the mapping of wind resources offshore where other measurements are costly and sparse. Satellite sensors operating at microwave frequencies m...

  4. A new method for improved hub height mean wind speed estimates using short-term hub height data

    Energy Technology Data Exchange (ETDEWEB)

    Lackner, Matthew A.; Rogers, Anthony L.; Manwell, James F.; McGowan, Jon G. [Wind Energy Center, Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst, 160 Governors Dr., Amherst, MA 01003 (United States)

    2010-10-15

    The estimation of the wind resource at the hub height of a wind turbine is one of the primary goals of site assessment. Because the measurement heights of meteorological towers (met towers) are typically significantly lower than turbine hub heights, a shear model is generally needed to extrapolate the measured wind resource at the lower measurement height to the hub height of the turbine. This paper presents methods for improving the estimate of the hub height wind resource from met tower data through the use of ground-based remote sensing devices. The methods leverage the two major advantages of these devices: their portability and their ability to measure at the wind turbine hub height. Specifically, the methods rely on augmenting the one year of met tower measurements with short-term measurements from a ground-based remote sensing device. The results indicate that the methods presented are capable of producing substantial improvements in the accuracy and uncertainty of shear extrapolation predictions. The results suggest that the typical site assessment process can be reevaluated, and alternative strategies that utilize ground-based remote sensing devices can be incorporated to significantly improve the process. (author)

  5. A New Approach for Offshore Wind Farm Energy Yields Calculation with Mixed Hub Height Wind Turbines

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Soltani, Mohsen

    2016-01-01

    In this paper, a mathematical model for calculating the energy yields of offshore wind farm with mixed types of wind turbines is proposed. The Jensen model is selected as the base and developed to a three dimension wake model to estimate the energy yields. Since the wind turbines are with different...... hub heights, the wind shear effect is also taken into consideration. The results show that the proposed wake model is effective in calculating the wind speed deficit. The calculation framework is applicable for energy yields calculation in offshore wind farms....

  6. Hexcrete Tower for Harvesting Wind Energy at Taller Hub Heights - Budget Period 2

    Energy Technology Data Exchange (ETDEWEB)

    Sritharan, Sri [Iowa State Univ., Ames, IA (United States)

    2017-05-01

    Interest in designing taller towers for wind energy production in the United States (U.S.) has been steadily growing. In May 2015, it was revealed that taller towers will make wind energy production a reality in all 50 states, including some states that have nearly zero renewables in their energy portfolio. Facilitating wind energy production feasibility in all 50 states will no doubt contribute to increasing the electricity produced by wind from 4.5% in 2013 to a targeted scenario of 35% by 2050 in the Wind Vision report. This project focuses on the Hexcrete tower concept developed for tall towers using High Strength Concrete (HSC) and/or Ultra-High Performance Concrete (UHPC). Among other benefits, the Hexcrete concept overcomes transportation and logistical challenges, thus facilitating construction of towers with hub heights of 100-m (328-ft) and higher. The goal of this project is to facilitate widespread deployment of Hexcrete towers for harvesting wind energy at 120 to 140-m (394 to 459-ft) hub heights and reduce the Levelized Cost of Energy (LCOE) of wind energy production in the U.S. The technical scope of the project includes detailed design and optimization of at least three wind turbine towers using the Hexcrete concept together with experimental validation and LCOE analyses and development of a commercialization plan.

  7. Final Report for Project: Impacts of stratification and non-equilibrium winds and waves on hub-height winds

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Edward G. [Univ. Corporation for Atmospheric Research, Boulder, CO (United States)

    2015-07-14

    This project used a combination of turbulence-resolving large-eddy simulations, single-column modeling (where turbulence is parameterized), and currently available observations to improve, assess, and develop a parameterization of the impact of non-equilibrium wave states and stratification on the buoy-observed winds to establish reliable wind data at the turbine hub-height level. Analysis of turbulence-resolving simulations and observations illuminates the non-linear coupling between the atmosphere and the undulating sea surface. This analysis guides modification of existing boundary layer parameterizations to include wave influences for upward extrapolation of surface-based observations through the turbine layer. Our surface roughness modifications account for the interaction between stratification and the effects of swell’s amplitude and wavelength as well as swell’s relative motion with respect to the mean wind direction. The single-column version of the open source Weather and Research Forecasting (WRF) model (Skamarock et al., 2008) serves as our platform to test our proposed planetary boundary layer parameterization modifications that account for wave effects on marine atmospheric boundary layer flows. WRF has been widely adopted for wind resource analysis and forecasting. The single column version is particularly suitable to development, analysis, and testing of new boundary layer parameterizations. We utilize WRF’s single-column version to verify and validate our proposed modifications to the Mellor-Yamada-Nakanishi-Niino (MYNN) boundary layer parameterization (Nakanishi and Niino, 2004). We explore the implications of our modifications for two-way coupling between WRF and wave models (e.g.,Wavewatch III). The newly implemented parameterization accounting for marine atmospheric boundary layer-wave coupling is then tested in three-dimensional WRF simulations at grid sizes near 1 km. These simulations identify the behavior of simulated winds at the

  8. Final Report for Project: Impacts of stratification and non-equilibrium winds and waves on hub-height winds

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Edward G. [Univ. Corporation for Atmospheric Research, Boulder, CO (United States)

    2015-07-14

    This project used a combination of turbulence-resolving large-eddy simulations, single-column modeling (where turbulence is parameterized), and currently available observations to improve, assess, and develop a parameterization of the impact of non-equilibrium wave states and stratification on the buoy-observed winds to establish reliable wind data at the turbine hub-height level. Analysis of turbulence-resolving simulations and observations illuminates the non-linear coupling between the atmosphere and the undulating sea surface. This analysis guides modification of existing boundary layer parameterizations to include wave influences for upward extrapolation of surface-based observations through the turbine layer. Our surface roughness modifications account for the interaction between stratification and the effects of swell’s amplitude and wavelength as well as swell’s relative motion with respect to the mean wind direction. The single-column version of the open source Weather and Research Forecasting (WRF) model (Skamarock et al., 2008) serves as our platform to test our proposed planetary boundary layer parameterization modifications that account for wave effects on marine atmospheric boundary layer flows. WRF has been widely adopted for wind resource analysis and forecasting. The single column version is particularly suitable to development, analysis, and testing of new boundary layer parameterizations. We utilize WRF’s single-column version to verify and validate our proposed modifications to the Mellor-Yamada-Nakanishi-Niino (MYNN) boundary layer parameterization (Nakanishi and Niino, 2004). We explore the implications of our modifications for two-way coupling between WRF and wave models (e.g.,Wavewatch III). The newly implemented parameterization accounting for marine atmospheric boundary layer-wave coupling is then tested in three-dimensional WRF simulations at grid sizes near 1 km. These simulations identify the behavior of simulated winds at the

  9. Hub Height Ocean Winds over the North Sea Observed by the NORSEWInD Lidar Array: Measuring Techniques, Quality Control and Data Management

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Stein, Detlef; Courtney, Michael

    2013-01-01

    In the North Sea, an array of wind profiling wind lidars were deployed mainly on offshore platforms. The purpose was to observe free stream winds at hub height. Eight lidars were validated prior to offshore deployment with observations from cup anemometers at 60, 80, 100 and 116 m on an onshore met....... The flow distortion around platforms was examined using wind tunnel experiments and computational fluid dynamics and it was found that at 100 m height wind observations by the lidars were not significantly influenced by flow distortion. Observations of the vertical wind profile shear exponent at hub height...

  10. On the Improvement of Numerical Weather Prediction by Assimilation of Hub Height Wind Information in Convection-Resulted Models

    Science.gov (United States)

    Declair, Stefan; Stephan, Klaus; Potthast, Roland

    2015-04-01

    Determining the amount of weather dependent renewable energy is a demanding task for transmission system operators (TSOs). In the project EWeLiNE funded by the German government, the German Weather Service and the Fraunhofer Institute on Wind Energy and Energy System Technology strongly support the TSOs by developing innovative weather- and power forecasting models and tools for grid integration of weather dependent renewable energy. The key in the energy prediction process chain is the numerical weather prediction (NWP) system. With focus on wind energy, we face the model errors in the planetary boundary layer, which is characterized by strong spatial and temporal fluctuations in wind speed, to improve the basis of the weather dependent renewable energy prediction. Model data can be corrected by postprocessing techniques such as model output statistics and calibration using historical observational data. On the other hand, latest observations can be used in a preprocessing technique called data assimilation (DA). In DA, the model output from a previous time step is combined such with observational data, that the new model data for model integration initialization (analysis) fits best to the latest model data and the observational data as well. Therefore, model errors can be already reduced before the model integration. In this contribution, the results of an impact study are presented. A so-called OSSE (Observation Simulation System Experiment) is performed using the convective-resoluted COSMO-DE model of the German Weather Service and a 4D-DA technique, a Newtonian relaxation method also called nudging. Starting from a nature run (treated as the truth), conventional observations and artificial wind observations at hub height are generated. In a control run, the basic model setup of the nature run is slightly perturbed to drag the model away from the beforehand generated truth and a free forecast is computed based on the analysis using only conventional

  11. Brief communication "Spatial and temporal variation of wind power at hub height over Europe"

    Directory of Open Access Journals (Sweden)

    S. Gisinger

    2013-05-01

    Full Text Available Wind power over Europe computed from two years of the new 100 m wind product from ECMWF at 16 km horizontal resolution is 20% of maximum capacity of an exemplary wind turbine power curve. This is five percent of maximum capacity less than extrapolated from 10 m winds using model roughness in the logarithmic law, but eight percent more than multiplying 10 m winds by a constant factor of 1.28 as in a previous study. The result from the new data set happens to be very close to the actual capacity factor of 21% for European wind turbines (Boccard, 2009. The capacity factor in high power regions between 50 and 58° N and most of northernmost Africa is almost 30%. The aggregation of wind power over Europe smooths onshore day-to-day fluctuations to at most 7 percentage points during 80% of the year.

  12. Climatology and trend of wind power resources in China and its surrounding regions: a revisit using Climate Forecast System Reanalysis data

    Science.gov (United States)

    Lejiang Yu; Shiyuan Zhong; Xindi Bian; Warren E. Heilman

    2015-01-01

    The mean climatology, seasonal and interannual variability and trend of wind speeds at the hub height (80 m) of modern wind turbines over China and its surrounding regions are revisited using 33-year (1979–2011) wind data from the Climate Forecast System Reanalysis (CFSR) that has many improvements including higher spatial resolution over previous global reanalysis...

  13. Results of large scale wind climatologically estimations

    Directory of Open Access Journals (Sweden)

    Andrea Kircsi

    2008-05-01

    Full Text Available The aim of this article is to describe theparticular field of climatology which analyzes airmovement characteristics regarding utilization of windfor energy generation. The article describes features ofwind energy potential available in Hungary compared towind conditions in other areas of the northern quartersphere in order to assist the wind energy use developmentin Hungary. Information on wind climate gives a solidbasis for financial and economic decisions ofstakeholders in the field of wind energy utilization.

  14. NORSEWInD satellite wind climatology

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Mouche, Alexis

    is to provide new offshore wind climatology map for the entire area of interest based on satellite remote sensing. This has been based on Synthetic Aperture Radar (SAR) from Envisat ASAR using 9000 scenes re-processed with ECMWF wind direction and CMOD-IFR. The number of overlapping samples range from 450....... QuikSCAT ocean wind vector observations have been analysed for the same four parameters and ASCAT for mean wind speed. All satellite data has been compared to in-situ observations available in the Norsewind project. SSM/I passive microwave wind speed data from 24 years observed around 6 times per day...... are used to estimate trends in offshore winds and interestingly a shift in the seasonal pattern is notice. All satellite-based wind products are valid at 10 m, thus it is desirable to lift winds to higher levels for wind energy products. A method has been suggested to lift winds from 10 m to hub...

  15. The WRF Model Forecast-Derived Low-Level Wind Shear Climatology over the United States Great Plains

    Directory of Open Access Journals (Sweden)

    Sukanta Basu

    2010-02-01

    Full Text Available For wind resource assessment projects, it is common practice to use a power-law relationship (U(z ~ zα and a fixed shear exponent (α = 1=7 to extrapolate the observed wind speed from a low measurement level to high turbine hub-heights. However, recent studies using tall-tower observations have found that the annual average shear exponents at several locations over the United States Great Plains (USGP are significantly higher than 1=7. These findings highlight the critical need for detailed spatio-temporal characterizations of wind shear climatology over the USGP, where numerous large wind farms will be constructed in the foreseeable future. In this paper, a new generation numerical weather prediction model—the Weather Research and Forecasting (WRF model, a fast and relatively inexpensive alternative to time-consuming and costly tall-tower projects, is utilized to determine whether it can reliably estimate the shear exponent and the magnitude of the directional shear at any arbitrary location over the USGP. Our results indicate that the WRF model qualitatively captures several low-level wind shear characteristics. However, there is definitely room for physics parameterization improvements for the WRF model to reliably represent the lower part of the atmospheric boundary layer.

  16. High resolution climatological wind measurements for wind energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, H. [Uppsala Univ. (Sweden). Dept. of Meteorology

    1996-12-01

    Measurements with a combined cup anemometer/wind vane instrument, developed at the Department of Meteorology in Uppsala, is presented. The instrument has a frequency response of about 1 Hz, making it suitable not only for mean wind measurements, but also for studies of atmospheric turbulence. It is robust enough to be used for climatological purposes. Comparisons with data from a hot-film anemometer show good agreement, both as regards standard deviations and the spectral decomposition of the turbulent wind signal. The cup anemometer/wind vane instrument is currently used at three sites within the Swedish wind energy research programme. These measurements are shortly described, and a few examples of the results are given. 1 ref, 10 figs

  17. Towards a generalization procedure for WRF mesoscale wind climatologies

    DEFF Research Database (Denmark)

    Hahmann, Andrea N.; Casso, P.; Campmany, E.

    We present a method for generalizing wind climatologies generated from mesoscale model output (e.g. the Weather, Research and Forecasting (WRF) model.) The generalization procedure is based on Wind Atlas framework of WAsP and KAMM/WAsP, and been extensively in wind resources assessment in DTU Wind...... generalized wind climatologies estimated by the microscale model WAsP and the methodology presented here. For the Danish wind measurements the mean absolute error in the ‘raw’ wind speeds is 9.2%, while the mean absolute error in the generalized wind speeds is 4.1%. The generalization procedure has been...... installed and automated in the Vortex downscaling chain for the MAPS calculation, which are computed at 3 km horizontal resolution grid. For the MAPS-derived wind speeds the mean absolute error in the ‘raw’ wind speeds is 17.3%, while the mean absolute error in the generalized winds is 10.7%....

  18. The Impacts of Atmospheric Stability on the Accuracy of Wind Speed Extrapolation Methods

    Directory of Open Access Journals (Sweden)

    Jennifer F. Newman

    2014-01-01

    Full Text Available The building of utility-scale wind farms requires knowledge of the wind speed climatology at hub height (typically 80–100 m. As most wind speed measurements are taken at 10 m above ground level, efforts are being made to relate 10-m measurements to approximate hub-height wind speeds. One common extrapolation method is the power law, which uses a shear parameter to estimate the wind shear between a reference height and hub height. The shear parameter is dependent on atmospheric stability and should ideally be determined independently for different atmospheric stability regimes. In this paper, data from the Oklahoma Mesonet are used to classify atmospheric stability and to develop stability-dependent power law fits for a nearby tall tower. Shear exponents developed from one month of data are applied to data from different seasons to determine the robustness of the power law method. In addition, similarity theory-based methods are investigated as possible alternatives to the power law. Results indicate that the power law method performs better than similarity theory methods, particularly under stable conditions, and can easily be applied to wind speed data from different seasons. In addition, the importance of using co-located near-surface and hub-height wind speed measurements to develop extrapolation fits is highlighted.

  19. Offshore wind climatology based on synergetic use of Envisat ASAR, ASCAT and QuikSCAT

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Mouche, Alexis; Badger, Merete

    2015-01-01

    The offshore wind climatology in the Northern European seas is analysed from ten years of Envisat synthetic aperture radar (SAR) images using a total of 9256 scenes, ten years of QuikSCAT and two years of ASCAT gridded ocean surface vector wind products and high-quality wind observations from four...

  20. An Update to the Warm-Season Convective Wind Climatology of KSC/CCAFS

    Science.gov (United States)

    Lupo, Kevin

    2012-01-01

    Total of 1100 convective events in the 17-year warm-season climatology at KSC/CCAFS. July and August typically are the peak of convective events, May being the minimum. Warning and non-warning level convective winds are more likely to occur in the late afternoon (1900-2000Z). Southwesterly flow regimes and wind directions produce the strongest winds. Storms moving from southwesterly direction tend to produce more warning level winds than those moving from the northerly and easterly directions.

  1. The climatology of the Red Sea - part 1: the wind

    KAUST Repository

    Langodan, Sabique

    2017-05-12

    The wind climatology of the Red Sea is described based on a 30-year high-resolution regional reanalysis generated using the Advanced Weather Research Forecasting model. The model was reinitialized on a daily basis with ERA-Interim global data and regional observations were assimilated using a cyclic three-dimensional variational approach. The reanalysis products were validated against buoy and scatterometers data. We describe the wind climatology and identify four major systems that determine the wind patterns in the Red Sea. Each system has a well-defined origin, and consequently different characteristics along the year. After analysing the relevant features of the basin in terms of their climatology, we investigate possible long-term trends in each system. It is found that there is a definite tendency towards lowering the strength of the wind speed, but at a different rate for different systems and periods of the year.

  2. Evaluation of wind flow with a nacelle-mounted, continuous wave wind lidar

    DEFF Research Database (Denmark)

    Medley, John; Barker, Will; Harris, Mike;

    2014-01-01

    IR, increasing the confidence in the ZephIR for measuring wind parameters in this configuration. SCADA data from the turbine was combined with measured wind speeds and directions to derive power curves from the mast data (hub-height) and from ZephIR data (hub-height and rotor-equivalent). The rotor...

  3. Climatology of Wind Direction Fluctuations at Risø

    DEFF Research Database (Denmark)

    Kristensen, Leif; Panofsky, H. A.

    1976-01-01

    Standard deviations of wind direction fluctuations at 76 m at Risø for the first half year of 1975 have been analyzed as functions of wind speed and temperature lapse rate, either measured near the surface or near the level of the azimuth variations. Between 31 and 37% of the variance of the stan...

  4. Comparison of high-latitude thermospheric meridional winds II: combined FPI, radar and model climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, E.M.; Aruliah, A.; Mueller-Wodarg, I.C.F.; Aylward, A. [Atmospheric Physics Lab., Univ. Coll. London, London (United Kingdom)

    2004-07-01

    The climatological behaviour of the thermospheric meridional wind above Kiruna, Sweden (67.4 N, 20.4 E) has been investigated for seasonal and solar cycle dependence using six different techniques, comprising both model and experimental sources. Model output from both the empirical Horizontal Wind Model (HWM) (Hedin et al., 1988) and the numerical coupled thermosphere and ionosphere model (CTIM) are compared to the measured behaviour at kiruna, as a single site example. The empirical International Reference Ionosphere (IRI) model is used as input to an implementation of servo theory, to provide another climatology combining empirical input with a theoretical framework. The experimental techniques have been introduced in a companion paper in this issue and provide climatologies from direct measurements, using fabry-perot interferometers (FPI), together with 2 separate techniques applied to the European incoherent scatter radar (EISCAT) database to derive neutral winds. One of these techniques uses the same implementation of servo theory as has been used with the IRI model. Detailed comparisons for each season and solar activity category allow for conclusions to be drawn as to the major influences on the climatological behaviour of the wind at this latitude. Comparison of the incoherent scatter radar (ISR) derived neutral winds with FPI, empirical model and numerical model winds is important to our understanding and judgement of the validity of the techniques used to derive thermospheric wind databases. The comparisons also test model performance and indicate possible reasons for differences found between the models. In turn, the conclusions point to possible improvements in their formulation. In particular it is found that the empirical models are over-reliant on mid-latitude data in their formulation, and fail to provide accurate estimates of the winds at high-latitudes. (orig.)

  5. Development of an Extratropical Storm Wind, Wave, and Water Level Climatology for the Offshore Mid-Atlantic

    Science.gov (United States)

    2015-08-01

    ER D C/ CH L TR -1 5- 11 Development of an Extratropical Storm Wind , Wave, and Water Level Climatology for the Offshore Mid-Atlantic...Development of an Extratropical Storm Wind , Wave, and Water Level Climatology for the Offshore Mid-Atlantic Michael F. Forte Field Research Facility...of the extreme offshore wind , wave, and water level climate in the mid-Atlantic region has been conducted for the U.S. Bureau of Safety and

  6. Examination of climatological wind patterns and simulated pollen dispersion in a complex island environment.

    Science.gov (United States)

    Viner, Brian J; Arritt, Raymond W; Westgate, Mark E

    2017-03-29

    Complex terrain creates small-scale circulations which affect pollen dispersion but may be missed by meteorological observing networks and coarse-grid meteorological models. On volcanic islands, these circulations result from differing rates of surface heating between land and sea as well as rugged terrain. We simulated the transport of bentgrass, ryegrass, and maize pollen from 30 sources within the agricultural regions of the Hawaiian island Kaua'i during climatological conditions spanning season conditions and the La Niña, El Niño, and neutral phases of the El Niño-Southern Oscillation. Both pollen size and source location had major effects on predicted dispersion over and near the island. Three patterns of pollen dispersion were identified in response to prevailing wind conditions: southwest winds transported pollen inland, funneling pollen grains through valleys; east winds transported pollen over the ocean, with dispersive tails for the smallest pollen grains following the mean wind and extending as far as the island of Ni'ihau 35 km away; and northeast winds moved pollen inland counter to the prevailing flow due to a sea breeze circulation that formed over the source region. These results are the first to predict the interactions between complex island terrain and local climatology on grass pollen dispersion. They demonstrate how numerical modeling can provide guidance for field trials by illustrating the common flow regimes present in complex terrain, allowing field trials to focus on areas where successful sampling is more likely to occur.

  7. Climatology of summer Shamal wind in the Middle East

    Science.gov (United States)

    Yu, Yan; Notaro, Michael; Kalashnikova, Olga V.; Garay, Michael J.

    2016-01-01

    The Middle Eastern Shamal is a strong north-northwesterly wind, capable of lifting dust from the Tigris-Euphrates basin and transporting it to the Persian Gulf and Arabian Peninsula. The present study explores the poorly understood spatial and temporal variability of summer Shamal on the diurnal, seasonal, and interannual time scales, along with its influence on dust storm activity and sensitivity to global patterns of sea surface temperature using a comprehensive set of observational data. Statistics of the summer Shamal season are quantified for the first time, including its onset, termination, duration, and the occurrence of distinct break periods. Based on a multistation criteria, the mean onset and termination of the Shamal season occur on 30 May ± 16 days (1 standard deviation) and 16 August ± 22 days, respectively. Anomalously early (late) onset and termination of the Shamal season are typically associated with La Niña (El Niño) conditions, which favor (inhibit) the development of the Iranian heat low in spring and inhibit (favor) its persistence into late summer. Dust source regions in the Tigris-Euphrates basin and Kuwait, as well as southeastward dust transport during the summer Shamal, which cannot be detected by satellite aerosol products alone, are identified, for the first time, from the Multiangle Imaging Spectroradiometer plume motion vector products and confirmed by surface observations and lidar data. A close interrelationship has been revealed among summertime dust activity across the eastern Arabian Peninsula, frequency of Shamal days, and duration of the Shamal season on the interannual time scales.

  8. Evaluation of wind flow with a nacelle-mounted continuous-wave lidar

    DEFF Research Database (Denmark)

    Medley, John; Slinger, Chris; Barker, Will;

    IR, increasing the confidence in the ZephIR for measuring wind parameters in this configuration. SCADA data from the turbine was combined with measured wind speeds and directions to derive power curves from the mast data (hub-height) and from ZephIR data (hub-height and rotor-equivalent). The rotor...

  9. Circulation response to ozone depletion depends on the zonal wind climatology

    Science.gov (United States)

    Lin, P.; Paynter, D.; Polvani, L. M.; Correa, G. J. P.; Ming, Y.; Ramaswamy, V.

    2016-12-01

    Circulation response to ozone depletion is studied in two General Climate Models: CAM3 and GFDL AM3. Both models are forced with identical ozone change and long time-slice simulations are performed to minimize the influence of internal variability. While both models simulate a lower stratospheric cooling and a poleward shift of extratropical jet with ozone depletion, the magnitudes of these changes are significantly different in the two models. The stronger stratospheric cooling simulated by CAM3 is due to a delayed onset of a negative dynamical feedback to polar stratospheric temperature changes, which is linked to its delayed breakdown of the polar vortex. By applying artificial zonal wind forcing to AM3 in the stratosphere, we are able to alter the zonal wind climatology over southern extratropical stratosphere in AM3 without directly affecting its own internal variability. This modified version of AM3 yields similar zonal wind climatology as CAM3. It also simulates stronger stratospheric cooling to the same ozone forcing compared to the original AM3. Since the delayed breakdown of the polar vortex is a common bias in most climate models, results of this study implies that the circulation response to ozone depletion simulated in most models might be overestimated.

  10. The Climatology of Neutral Winds in the MLT Region as Observed From Orbit

    Science.gov (United States)

    Niciejewski, R.; Skinner, W.; Gell, D.; Cooper, M.; Marsh, A.; Killeen, T.; Wu, Q.; Solomon, S.; Ortland, D.; Drob, D.; Emmert, J.

    2005-12-01

    Unique observations of the horizontal neutral winds in the altitude range 70 to 115 km have been performed from satellite platforms by HRDI and WINDII (UARS) and by TIDI (TIMED), the former since September 1991 and the latter since January 2002. All three experiments observed airglow on the terrestrial limb and derived vertical wind profiles of geophysical quantities by inverting altitude scans of Doppler shifted emission spectra. As a result, the global mesosphere / lower thermosphere region has been sampled for 14 years by a common technique resulting in an unparalleled neutral wind database. This database will be one of the key contributions to an improved Horizontal Wind Model (HWM). This paper will describe results from the first long term climatological study of the MLT region based on satellite wind measurements. The basic dynamic structure in the MLT is a tide, which also has long-term variation that has similar periods to the 27-month QBO (quasi-biennial oscillation) and the SAO (semi-annual oscillation). Signatures of ultra-long variability require analysis of the full wind database.

  11. Climatology of northern polar latitude MLT dynamics: mean winds and tides

    Directory of Open Access Journals (Sweden)

    G. Kishore Kumar

    2010-10-01

    Full Text Available Mean winds and tides in the northern polar Mesosphere and Lower Thermosphere (MLT have been studied using meteor radars located at Resolute Bay (75° N, 95° W and Yellowknife (62.5° N, 114.3° W. The measurements for Resolute Bay span almost 12 years from July 1997 to February 2009 and the Yellowknife data cover 7 years from June 2002 to October 2008. The analysis reveals similar wind flow over both sites with a difference in magnitude. The summer zonal flow is westward at lower heights, eastward at upper heights and the winter zonal flow is eastward at all heights. The winter meridional flow is poleward and sometimes weakly equatorward, while non winter months show equatorward flow, with a strong equatorward jet during mid-summer months. The zonal and meridional winds show strong interannual variation with a dominant annual variation as well as significant latitudinal variation. Year to year variability in both zonal and meridional winds exists, with a possible solar cycle dependence. The diurnal, semidiurnal and terdiurnal tides also show large interannual variability and latitudinal variation. The diurnal amplitudes are dominated by an annual variation. The climatological monthly mean winds are compared with CIRA 86, GEWM and HWM07 and the climatological monthly mean amplitudes and phases of diurnal and semidiurnal tides are compared with GSWM00 predictions. The GEWM shows better agreement with observations than the CIRA 86 and HWM07. The GSWM00 model predictions need to be modified above 90 km. The agreements and disagreements between observations and models are discussed.

  12. Global climatology of the wind vector rotation - implications for the orographic gravity waves propagation

    Science.gov (United States)

    Pisoft, Petr; Sacha, Petr; Kuchar, Ales

    2015-04-01

    The gravity waves spectrum is shaped not only by different sources but it also reflects tropospheric background conditions contributing to filtering of various gravity waves. This could be most easily illustrated for the propagation of the orographic gravity waves that are critically filtered when the wind speed is zero. This condition is ensured in case of the directional shear exceeding 180°. Above regions where it is fulfilled, one can rule out the possibility of orographic GW modes contributing to the observed GW activity and vice versa regions of small wind rotation in the lower levels are often precursors of enhanced GW activity higher. In this study, we have performed a global analysis of the background conditions with a focus on the rotation of the ground level winds. We have analyzed MERRA and JRA-55 time series. The results provided climatology of atmospheric regions with the conditions favorable for the upward propagation of the orographic gravity waves from the troposphere into the stratosphere. The regions are detected mainly over areas where tropospheric and stratospheric jets coincide. The study is supplemented by a global analysis of the fields of potential energy of disturbances as a proxy for gravity waves activity using COSMIC GPS RO data.

  13. Meteorological Controls on Wind Turbine Wakes

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca J.; Hansen, Kurt Schaldemose; Pryor, S.C.

    2013-01-01

    The primary control on the magnitude of the power losses induced by wind turbine wakes in large wind farms is the hub-height wind speed via its link to the turbine thrust coefficient. Hence, at low to moderate wind speeds (between cut-in and rated turbine wind speeds) when the thrust coefficient...

  14. Development of a Climatology of Vertically Complete Wind Profiles from Doppler Radar Wind Profiler Systems

    Science.gov (United States)

    Barbre, Robert E., Jr.

    2015-01-01

    This paper describes in detail the QC and splicing methodology for KSC's 50- and 915-MHz DRWP measurements that generates an extensive archive of vertically complete profiles from 0.20-18.45 km. The concurrent POR from each archive extends from April 2000 to December 2009. MSFC NE applies separate but similar QC processes to each of the 50- and 915-MHz DRWP archives. DRWP literature and data examination provide the basis for developing and applying the automated and manual QC processes on both archives. Depending on the month, the QC'ed 50- and 915-MHz DRWP archives retain 52-65% and 16-30% of the possible data, respectively. The 50- and 915-MHz DRWP QC archives retain 84-91% and 85-95%, respectively, of all the available data provided that data exist in the non- QC'ed archives. Next, MSFC NE applies an algorithm to splice concurrent measurements from both DRWP sources. Last, MSFC NE generates a composite profile from the (up to) five available spliced profiles to effectively characterize boundary layer winds and to utilize all possible 915-MHz DRWP measurements at each timestamp. During a given month, roughly 23,000-32,000 complete profiles exist from 0.25-18.45 km from the composite profiles' archive, and approximately 5,000- 27,000 complete profiles exist from an archive utilizing an individual 915-MHz DRWP. One can extract a variety of profile combinations (pairs, triplets, etc.) from this sample for a given application. The sample of vertically complete DRWP wind measurements not only gives launch vehicle customers greater confidence in loads and trajectory assessments versus using balloon output, but also provides flexibility to simulate different DOL situations across applicable altitudes. In addition to increasing sample size and providing more flexibility for DOL simulations in the vehicle design phase, the spliced DRWP database provides any upcoming launch vehicle program with the capability to utilize DRWP profiles on DOL to compute vehicle steering

  15. A climatology of Brazilian surface wind speed trends using in-situ and climate reanalysis datasets from 1980-2014

    Science.gov (United States)

    Gilliland, J. M.; Keim, B. D.

    2015-12-01

    Wind speed trends have been extensively researched for the Northern Hemisphere and Australia. The general consensus among scientists is that wind speeds have declined over the past century. However, a minimal amount of research has focused on understanding how wind speeds changed across Brazil based on temporal and geographical perspectives. Therefore, this study provides a climatological assessment of wind speed trends across Brazil using in-situ and climatic model datasets from 1980-2014. Seasonal and annual trends are determined across the study area using linear and quantile regression. Geographical Information Systems is used to interpret and understand how wind speed trends have changed across Brazil. Preliminary results show two distinct wind speed trend patterns exist across Brazil. The largest wind speed magnitude increases occurred along northeastern and coastal Brazil, where as decreasing wind speeds have been observed for central and southeastern Brazil. Furthermore, quantile regression also shows the largest seasonal and annual wind trend fluctuations occur at lower (5%) and upper percentiles (95%) for both in-situ and climate model datasets. As a result, these findings indicate possible alterations in atmospheric and oceanic circulations could be affecting wind speed trends across Brazil and warrants further investigation and research.

  16. Basin-scale wind transport during the MILAGRO field campaign and comparison to climatology using cluster analysis

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2007-09-01

    Full Text Available The MILAGRO field campaign was a multi-agency international collaborative project to evaluate the regional impacts of the Mexico City air pollution plume as a means of understanding urban impacts on the global climate. Mexico City lies on an elevated plateau with mountains on three sides and has complex mountain and surface-driven wind flows. This paper asks what the wind transport was in the basin during the field campaign and how representative it was of the climatology. Surface meteorology and air quality data, radiosoundings and radar wind profiler data were collected at sites in the basin and its vicinity. Cluster analysis is used to identify the dominant wind patterns both during the campaign and within the past 10 years of operational data from the warm dry season. Our analysis shows that March 2006 was representative of typical flow patterns experienced in the basin. Six episode types were identified for the basin scale circulation providing a way of interpreting atmospheric chemistry and particulate data collected during the campaign. Decoupling between surface winds and those aloft had a strong influence in leading to convection and poor air quality episodes. Hourly characterisation of wind circulation during the MILAGRO, MCMA-2003 and IMADA field campaigns will enable the comparisons of similar air pollution episodes and the evaluation of the impact of wind transport on measurements of the atmospheric chemistry taking place in the basin.

  17. Basin-scale wind transport during the MILAGRO field campaign and comparison to climatology using cluster analysis

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2008-03-01

    Full Text Available The MILAGRO field campaign was a multi-agency international collaborative project to evaluate the regional impacts of the Mexico City air pollution plume as a means of understanding urban impacts on the global climate. Mexico City lies on an elevated plateau with mountains on three sides and has complex mountain and surface-driven wind flows. This paper asks what the wind transport was in the basin during the field campaign and how representative it was of the climatology. Surface meteorology and air quality data, radiosondes and radar wind profiler data were collected at sites in the basin and its vicinity. Cluster analysis was used to identify the dominant wind patterns both during the campaign and within the past 10 years of operational data from the warm dry season. Our analysis shows that March 2006 was representative of typical flow patterns experienced in the basin. Six episode types were identified for the basin-scale circulation providing a way of interpreting atmospheric chemistry and particulate data collected during the campaign. Decoupling between surface winds and those aloft had a strong influence in leading to convection and poor air quality episodes. Hourly characterisation of wind circulation during the MILAGRO, MCMA-2003 and IMADA field campaigns enables the comparisons of similar air pollution episodes and the evaluation of the impact of wind transport on measurements of the atmospheric chemistry taking place in the basin.

  18. Spectral coherence model for power fluctuations in a wind farm

    DEFF Research Database (Denmark)

    Vigueras-Rodriguez, A.; Sørensen, Poul Ejnar; Viedma, A.;

    2012-01-01

    This paper provides a model for the coherence between wind speeds located in a horizontal plane corresponding to hub height of wind turbines in a large wind farm. The model has been developed using wind speed and power measurements from the 72 Wind Turbines and two of the meteorological masts from...

  19. Dependence of optimal wind turbine spacing on wind farm length

    NARCIS (Netherlands)

    Stevens, Richard J.A.M.

    2016-01-01

    Recent large eddy simulations have led to improved parameterizations of the effective roughness height of wind farms. This effective roughness height can be used to predict the wind velocity at hub-height as function of the geometric mean of the spanwise and streamwise turbine spacings and the turbi

  20. Dependence of optimal wind turbine spacing on wind farm length

    NARCIS (Netherlands)

    Stevens, Richard Johannes Antonius Maria

    2016-01-01

    Recent large eddy simulations have led to improved parameterizations of the effective roughness height of wind farms. This effective roughness height can be used to predict the wind velocity at hub-height as function of the geometric mean of the spanwise and streamwise turbine spacings and the

  1. Extreme wind estimate for Hornsea wind farm

    DEFF Research Database (Denmark)

    Larsén, Xiaoli Guo

    The purpose of this study is to provide estimation of the 50-year winds of 10 min and 1-s gust value at hub height of 100 m, as well as the design parameter shear exponent for the Hornsea offshore wind farm. The turbulence intensity required for estimating the gust value is estimated using two...... approaches. One is through the measurements from the wind Doppler lidar, WindCube, which implies serious uncertainty, and the other one is through similarity theory for the atmospheric surface layer where the hub height is likely to belong to during strong storms. The turbulence intensity for storm wind...... strength is taken as 0.1. The shear exponents at several heights were calculated from the measurements. The values at 100 m are less than the limit given by IEC standard for all sectors. The 50-year winds have been calculated from various global reanalysis and analysis products as well as mesoscale models...

  2. Climatology and interannual variability of high-wind occurrence over ocean (Invited)

    Science.gov (United States)

    Xie, S.; Cheng, X.; Sampe, T.; Tokinaga, H.

    2010-12-01

    High winds at sea are feared by sailors, but their distribution is poorly known because ships have avoided them as much as possible. The accumulation of space-borne scatterometer measurements now allows a global mapping of high winds over the ocean. QuikSCAT data for 1999-2009 show that high-wind events, defined as wind speeds greater than 20 m s-1 (“strong gale” and higher on the Beaufort scale), mostly happen in winter. Over coastal regions, land orography is the major cause of high winds, forcing wind jets of various types. Over the open ocean, high winds tend to be collocated with the extratropical storm tracks, and on the warm flank of major sea surface temperature (SST) fronts. The use of Special Sensor Microwave Imagers (SSM/Is) extends satellite wind-speed measurements back to 1987. Interannual variability of high-wind occurrence is studied over the North Atlantic. The North Atlantic Oscillation is an important factor for variability in high-wind occurrence, and so is the modulation of orographic wind jets at the tip of Greenland. Near SST fronts, changes in cross-frontal winds alter high-wind occurrence by changing near-surface atmospheric stability and vertical mixing.

  3. Characteristics for wind energy and wind turbines by considering vertical wind shear

    Institute of Scientific and Technical Information of China (English)

    郑玉巧; 赵荣珍

    2015-01-01

    The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm, the power-law process was used to simulate the wind speeds at a hub height of 60 m. The Weibull and Rayleigh distributions were chosen to express the wind speeds at two different heights. The parameters in the model were estimated via the least square (LS) method and the maximum likelihood estimation (MLE) method, respectively. An adjusted MLE approach was also presented for parameter estimation. The main indices of wind energy characteristics were calculated based on observational wind speed data. A case study based on the data of Hexi area, Gansu Province of China was given. The results show that MLE method generally outperforms LS method for parameter estimation, and Weibull distribution is more appropriate to describe the wind speed at the hub height.

  4. Reassessing Wind Potential Estimates for India: Economic and Policy Implications

    Energy Technology Data Exchange (ETDEWEB)

    Phadke, Amol; Bharvirkar, Ranjit; Khangura, Jagmeet

    2011-09-15

    We assess developable on-shore wind potential in India at three different hub-heights and under two sensitivity scenarios – one with no farmland included, the other with all farmland included. Under the “no farmland included” case, the total wind potential in India ranges from 748 GW at 80m hub-height to 976 GW at 120m hub-height. Under the “all farmland included” case, the potential with a minimum capacity factor of 20 percent ranges from 984 GW to 1,549 GW. High quality wind energy sites, at 80m hub-height with a minimum capacity factor of 25 percent, have a potential between 253 GW (no farmland included) and 306 GW (all farmland included). Our estimates are more than 15 times the current official estimate of wind energy potential in India (estimated at 50m hub height) and are about one tenth of the official estimate of the wind energy potential in the US.

  5. The climatological relationships between wind and solar energy supply in Britain

    CERN Document Server

    Bett, Philip E

    2016-01-01

    We use reanalysis data to investigate the daily co-variability of wind and solar irradiance in Britain, and its implications for renewable energy supply balancing. The joint distribution of daily-mean wind speeds and irradiances shows that irradiance has a much stronger seasonal cycle than wind, due to the rotational tilt of the Earth. Irradiance is weakly anticorrelated with wind speed throughout the year ($-0.4 \\lesssim \\rho \\lesssim -0.2$): there is a weak tendency for windy days to be cloudier. This is particularly true in Atlantic-facing regions (western Scotland, south-west England). The east coast of Britain has the weakest anticorrelation, particularly in winter, primarily associated with a relative increase in the frequency of clear-but-windy days. We also consider the variability in total power output from onshore wind turbines and solar photovoltaic panels. In all months, daily variability in total power is always reduced by incorporating solar capacity. The scenario with the least seasonal variabi...

  6. Current and Future Opportunities for Wind Power in the Southeast

    Energy Technology Data Exchange (ETDEWEB)

    Tinnesand, Heidi; Roberts, Owen; Lantz, Eric

    2016-10-05

    This presentation discusses future wind opportunities in the Southeast including factors such as changes in wind turbine technology, historical innovation trends, and forecast demand growth among regions. The presentation covers the current status of wind in the United States at 80-m hub height and the near-future outlook with a hub height at 110 to 140 meters. Future cost reductions in 2030 and beyond are also explored. Heidi Tinnesand presented this information to a utility advisory group meeting in Charlotte, North Carolina, on October 5, 2016.

  7. Rotor equivalent wind speed for power curve measurement – comparative exercise for IEA Wind Annex 32

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Cañadillas, B.; Clifton, A.;

    2014-01-01

    was the definition of the segment area used as weighting for the wind speeds measured at the various heights in the calculation of the REWS. This comparative exercise showed that the REWS method results in a significant difference compared to the standard method using the wind speed at hub height in conditions...

  8. A 15-year climatology of wind pattern impacts on surface ozone in Houston, Texas

    Science.gov (United States)

    Souri, Amir Hossein; Choi, Yunsoo; Li, Xiangshang; Kotsakis, Alexander; Jiang, Xun

    2016-06-01

    Houston is recognized for its large petrochemical industrial facilities providing abundant radicals for tropospheric ozone formation. Fortunately, maximum daily 8-h average (MDA8) surface ozone concentrations have declined in Houston (- 0.6 ± 0.3 ppbv yr- 1) during the summers (i.e., May to September) of 2000 to 2014, possibly due to the reductions in precursor emissions by effective control policies. However, it is also possible that changes in meteorological variables have affected ozone concentrations. This study focused on the impact of long-term wind patterns which have the highest impact on ozone in Houston. The analysis of long-term wind patterns can benefit surface ozone studies by 1) providing wind patterns that distinctly changed ozone levels, 2) investigating the frequency of patterns and the respective changes and 3) estimating ozone trends in specific wind patterns that local emissions are mostly involved, thus separating emissions impacts from meteorology to some extent. To this end, the 900-hPa flow patterns in summers of 2000 to 2014 were clustered in seven classes (C1-C7) by deploying an unsupervised partitioning method. We confirm the characteristics of the clusters from a backward trajectory analysis, monitoring networks, and a regional chemical transport model simulation. The results indicate that Houston has experienced a statistically significant downward trend (- 0.6 ± 0.4 day yr- 1) of the cluster of weak easterly and northeasterly days (C4), when the highest fraction of ozone exceedances (MDA8 > 70 ppbv) occurred. This suggests that the reduction in ozone precursors was not the sole reason for the decrease in ozone exceedance days (- 1.5 ± 0.6 day yr- 1). Further, to examine the efficiency of control policies intended to reduce the amount of ozone, we estimated the trend of MDA8 ozone in C4 and C5 (weak winds) days when local emissions are primarily responsible for high ambient ozone levels. Both C4 and C5 show a large reduction in the

  9. Global Climatology of the Coastal Low-Level Wind Jets using different Reanalysis

    Science.gov (United States)

    Lima, Daniela C. A.; Soares, Pedro M. M.; Semedo, Alvaro; Cardoso, Rita M.

    2016-04-01

    Coastal Low-Level Jets (henceforth referred to as "coastal jets" or simply as CLLJ) are low-tropospheric mesoscale wind features, with wind speed maxima confined to the marine atmospheric boundary layer (MABL), typically bellow 1km. Coastal jets occur in the eastern flank of the semi-permanent subtropical mid-latitude high pressure systems, along equatorward eastern boundary currents, due to a large-scale synoptic forcing. The large-scale synoptic forcing behind CLLJ occurrences is a high pressure system over the ocean and a thermal low inland. This results in coastal parallel winds that are the consequence of the geostrophic adjustment. CLLJ are found along the California (California-Oregon) and the Canary (Iberia and Northeastern Africa) currents in the Northern Hemisphere, and along the Peru-Humboldt (Peru-Chile), Benguela (Namibia) and Western Australia (West Australia) currents in the Southern Hemisphere. In the Arabian Sea (Oman CLLJ), the interaction between the high pressure over the Indian Ocean in summer (Summer Indian Monsoon) and the Somali (also known as Findlater) Jet forces a coastal jet wind feature off the southeast coast of Oman. Coastal jets play an important role in the regional climates of the mid-latitude western continental regions. The decrease of the sea surface temperatures (SST) along the coast due to upwelling lowers the evaporation over the ocean and the coast parallel winds prevents the advection of marine air inshore. The feedback processes between the CLLJ and upwelling play a crucial role in the regional climate, namely, promoting aridity since the parallel flow prevents the intrusion of moisture inland, and increasing fish stocks through the transport of rich nutrient cold water from the bottom. In this study, the global coastal low-level wind jets are identified and characterized using an ensemble of three reanalysis, the ECMWF Interim Reanalysis (ERA-Interim), the Japanese 55-year Reanalysis (JRA-55) and the NCEP Climate Forecast

  10. Santa Ana Winds of Southern California: Their Climatology and Variability Spanning 6.5 Decades from Regional Dynamical Modelling

    Science.gov (United States)

    Guzman-Morales, J.; Gershunov, A.

    2015-12-01

    Santa Ana Winds (SAWs) are an integral feature of the regional climate of Southern California/Northern Baja California region. In spite of their tremendous episodic impacts on the health, economy and mood of the region, climate-scale behavior of SAW is poorly understood. In the present work, we identify SAWs in mesoscale dynamical downscaling of a global reanalysis product and construct an hourly SAW catalogue spanning 65 years. We describe the long-term SAW climatology at relevant time-space resolutions, i.e, we developed local and regional SAW indices and analyse their variability on hourly, daily, annual, and multi-decadal timescales. Local and regional SAW indices are validated with available anemometer observations. Characteristic behaviors are revealed, e.g. the SAW intensity-duration relationship. At interdecadal time scales, we find that seasonal SAW activity is sensitive to prominent large-scale low-frequency modes of climate variability rooted in the tropical and north Pacific ocean-atmosphere system that are also known to affect the hydroclimate of this region. Lastly, we do not find any long-term trend in SAW frequency and intensity as previously reported. Instead, we identify a significant long-term trend in SAW behavior whereby contribution of extreme SAW events to total seasonal SAW activity has been increasing at the expense of moderate events. These findings motivate further investigation on SAW evolution in future climate and its impact on wildfires.

  11. Reduction of horizontal wind speed in a boundary layer with obstacles

    DEFF Research Database (Denmark)

    Emeis, S.; Frandsen, S.

    1993-01-01

    The reduction of horizontal wind speed at hub height in an infinite cluster of wind turbines is computed from a balance between a loss of horizontal momentum due to the drag and replenishment from above by turbulent fluxes. This reduction is derived without assumptions concerning the vertical wind...

  12. Wind speed forecasting for wind energy applications

    Science.gov (United States)

    Liu, Hong

    With more wind energy being integrated into our grid systems, forecasting wind energy has become a necessity for all market participants. Recognizing the market demands, a physical approach to site-specific hub-height wind speed forecasting system has been developed. This system is driven by the outputs from the Canadian Global Environmental Multiscale (GEM) model. A simple interpolation approach benchmarks the forecasting accuracy inherited from GEM. Local, site specific winds are affected on a local scale by a variety of factors including representation of the land surface and local boundary-layer process over heterogeneous terrain which have been a continuing challenge in NWP models like GEM with typical horizontal resolution of order 15-km. In order to resolve these small scale effects, a wind energy industry standard model, WAsP, is coupled with GEM to improve the forecast. Coupling the WAsP model with GEM improves the overall forecasts, but remains unsatisfactory for forecasting winds with abrupt surface condition changes. Subsequently in this study, a new coupler that uses a 2-D RANS model of boundary-layer flow over surface condition changes with improved physics has been developed to further improve the forecasts when winds coming from a water surface to land experience abrupt changes in surface conditions. It has been demonstrated that using vertically averaged wind speeds to represent geostrophic winds for input into the micro-scale models could reduce forecast errors. The hub-height wind speed forecasts could be further improved using a linear MOS approach. The forecasting system has been evaluated, using a wind energy standard evaluation matrix, against data from an 80-m mast located near the north shore of Lake Erie. Coupling with GEM-LAM and a power conversion model using a theoretical power curve have also been investigated. For hub-height wind speeds GEM appears to perform better with a 15-Ian grid than the high resolution GEM-2.5Ian version at the

  13. Improving the Accuracy of Wind Turbine Power Curve Validation by the Rotor Equivalent Wind Speed Concept

    Science.gov (United States)

    Scheurich, Frank; Enevoldsen, Peder B.; Paulsen, Henrik N.; Dickow, Kristoffer K.; Fiedel, Moritz; Loeven, Alex; Antoniou, Ioannis

    2016-09-01

    The measurement of the wind speed at hub height is part of the current IEC standard procedure for the power curve validation of wind turbines. The inherent assumption is thereby made that this measured hub height wind speed sufficiently represents the wind speed across the entire rotor area. It is very questionable, however, whether the hub height wind speed (HHWS) method is appropriate for rotor sizes of commercial state-of-the-art wind turbines. The rotor equivalent wind speed (REWS) concept, in which the wind velocities are measured at several different heights across the rotor area, is deemed to be better suited to represent the wind speed in power curve measurements and thus results in more accurate predictions of the annual energy production (AEP) of the turbine. The present paper compares the estimated AEP, based on HHWS power curves, of two different commercial wind turbines to the AEP that is based on REWS power curves. The REWS was determined by LiDAR measurements of the wind velocities at ten different heights across the rotor area. It is shown that a REWS power curve can, depending on the wind shear profile, result in higher, equal or lower AEP estimations compared to the AEP predicted by a HHWS power curve.

  14. Cost of Wind Energy in the United States: Trends from 2007 to 2012 (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Hand, M.

    2015-01-01

    This presentation provides an overview of recent technology trends observed in the United States including project size, turbine size, rotor diameter, hub height, annual average wind speed, and annual energy production. It also highlights area where system analysis is required to fully understand how these technology trends relate to the cost of wind energy.

  15. Cost of Wind Energy in the United States: Trends from 2007 to 2012 (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Hand, M.

    2015-01-01

    This presentation provides an overview of recent technology trends observed in the United States including project size, turbine size, rotor diameter, hub height, annual average wind speed, and annual energy production. It also highlights area where system analysis is required to fully understand how these technology trends relate to the cost of wind energy.

  16. Wind Energy Potential: Current representation and projections for the European domain

    Science.gov (United States)

    Davy, Richard; Gnatiuk, Natalia; Bobylev, Leonid; Pettersson, Lasse

    2016-04-01

    We have used the publically available CORDEX datasets to quantify the ability of a current regional climate model (SMHI-RCA4) to simulate the wind energy potential in the Black sea region using 5 different global climate models for the boundary conditions. The regional climate model results are compared to the ERA-Interim reanalyses over a common period, 1979-2005, and we use Taylor plots to demonstrate the effect of different global climate models on the regional climate simulations. Wind energy potential is calculated from the daily hub-height (120 m) wind speeds by extrapolating the available 10 m wind speeds using a power-law wind profile approximation. In general we find that the regional climate model produces stronger surface winds over the Black Sea region as compared to the ERA-Interim reanalysis, which we relate to the difference in model resolution. We also assess the projected changes to the wind energy potential in the CORDEX EUR-11 region from the current period to the near future (2021-2050), and to the late 21st century (2061-2090). We use a single model ensemble approach to assess the robustness of the projected changes, depending upon the choice of global climate model used for the boundary conditions. To understand the context of the changes in wind energy potential in the region, we include the changing climatology of the upper level (850 hPa) winds over these periods. This work was supported by the EU FP7 Project, Grant agreement No.: 287844. "Towards COast to COast NETworks of marine protected areas (from the shore to the high and deep sea), coupled with sea-based wind energy potential (CoCoNet)".

  17. Santa Ana Winds of Southern California: Their climatology, extremes, and behavior spanning six and a half decades

    Science.gov (United States)

    Guzman-Morales, Janin; Gershunov, Alexander; Theiss, Jurgen; Li, Haiqin; Cayan, Daniel

    2016-03-01

    Santa Ana Winds (SAWs) are an integral feature of the regional climate of Southern California/Northern Baja California region, but their climate-scale behavior is poorly understood. In the present work, we identify SAWs in mesoscale dynamical downscaling of a global reanalysis from 1948 to 2012. Model winds are validated with anemometer observations. SAWs exhibit an organized pattern with strongest easterly winds on westward facing downwind slopes and muted magnitudes at sea and over desert lowlands. We construct hourly local and regional SAW indices and analyze elements of their behavior on daily, annual, and multidecadal timescales. SAWs occurrences peak in winter, but some of the strongest winds have occurred in fall. Finally, we observe that SAW intensity is influenced by prominent large-scale low-frequency modes of climate variability rooted in the tropical and north Pacific ocean-atmosphere system.

  18. IMPER: Characterization of the Wind Field over a Large Wind Turbine Rotor

    DEFF Research Database (Denmark)

    Schmidt Paulsen, Uwe; Wagner, Rozenn

    A modern wind turbine rotor with a contemporary rotor size would easily with the tips penetrate the air between 116 m and 30 m and herby experience effects of different wind. With current rules on power performance measurements such as IEC 61400-121 the reference wind speed is measured at hub...... height, an oversimplification of the wind energy power over the rotor disk area is carried out. The project comprised a number of innovative and coordinated measurements on a full scale turbine with remote sensing technology and simulations on a 500 kW wind turbine for the effects of wind field...

  19. Some challenges of wind modelling for modern wind turbines: The Weibull distribution

    OpenAIRE

    Gryning, Sven-Erik; Batchvarova, Ekatarina; Floors, Rogier; Pena Diaz, Alfredo

    2012-01-01

    Wind power assessments, as well as forecast of wind energy production, are key issues in wind energy and grid related studies. However the hub height of today’s wind turbines is well above the surface layer. Wind profiles studies based on mast data show that the wind profile above the surface layer depends on the planetary boundary layer (PBL) structure and height, thus parameters that are not accounted for in today’s traditional applied flow simulation models and parameterizations. Here we r...

  20. Offshore wind resource estimation for wind energy

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Mouche, A.

    2010-01-01

    Satellite remote sensing from active and passive microwave instruments is used to estimate the offshore wind resource in the Northern European Seas in the EU-Norsewind project. The satellite data include 8 years of Envisat ASAR, 10 years of QuikSCAT, and 23 years of SSM/I. The satellite...... observations are compared to selected offshore meteorological masts in the Baltic Sea and North Sea. The overall aim of the Norsewind project is a state-of-the-art wind atlas at 100 m height. The satellite winds are all valid at 10 m above sea level. Extrapolation to higher heights is a challenge. Mesoscale...... modeling of the winds at hub height will be compared to data from wind lidars observing at 100 m above sea level. Plans are also to compare mesoscale model results and satellite-based estimates of the offshore wind resource....

  1. Is a wind turbine a point source? (L).

    Science.gov (United States)

    Makarewicz, Rufin

    2011-02-01

    Measurements show that practically all noise of wind turbine noise is produced by turbine blades, sometimes a few tens of meters long, despite that the model of a point source located at the hub height is commonly used. The plane of rotating blades is the critical location of the receiver because the distances to the blades are the shortest. It is shown that such location requires certain condition to be met. The model is valid far away from the wind turbine as well.

  2. Baseline climatology of extremely high vertical wind shears' values over Europe based on ERA-Interim reanalysis

    Science.gov (United States)

    Palarz, Angelika; Celiński-Mysław, Daniel

    2017-04-01

    The dominant role in the development of deep convection is played by kinematic and thermodynamic conditions, as well as atmospheric circulation, land cover and local relief. Severe thunderstorms are considerably more likely to form in environments with large values of convective available potential energy (CAPE) and significant magnitude of vertical wind shears (VWSs). According to the most recent research, the tropospheric wind shears have an important influence on intensity, longevity and organisation of the primary convective systems - bow echoes, squall lines and supercell thunderstorms. This study, in turn, examines the role of wind structure in controlling the spatial and temporal variability of VWSs over Europe. Considering the importance of the kinematic conditions for the convective systems formation, research is limited exclusively to 0-1 km, 0-3 km and 0-6 km wind shears. In order to compute the VWS' values, the data derived from ERA-Interim reanalysis for the period 1981-2015 was applied. It consisted of U and V wind components with 12-hourly sampling and horizontal resolution of 0.75×0.75°. The VWS' values were calculated as wind difference between two levels - this entails that the hodograph's shape was not considered (e.g. Clark 2013, Pucik et. al 2015). We have analysed both VWS' mean values (MN) and frequency of VWSs exceeding assumed thresholds (FQ). Taking into account previous studies (e.g. Rasmussen & Blanchard 1998, Schneider et al. 2006, Schaumann & Przybylinski 2012), the thresholds for extremely high values of vertical wind shears were set at 10 m/s for 0-1 km shear, 15 m/s for 0-3 km shear and 18 m/s for 0-6 km shear. Both MN and FQ values were characterised by strong temporal variability, as well as significant spatial differentiation over the research area. A clear diurnal cycle was identified in the case of 0-1 km shear, while seasonal variability was typical for 0-3 km and 0-6 km shears. Regardless of the season, 0-1 km shear reached

  3. Wind Atlas of Bay of Bengal with Satellite Wind Measurement

    DEFF Research Database (Denmark)

    Nadi, Navila Rahman

    The objective of this study is to obtain appropriate offshore location in the Bay of Bengal, Bangladesh for further development of wind energy. Through analyzing the previous published works, no offshore wind energy estimation has been found here. That is why, this study can be claimed as the first...... footstep towards offshore wind energy analysis for this region. Generally, it is difficult to find offshore wind data relative to the wind turbine hub heights, therefore a starting point is necessary to identify the possible wind power density of the region. In such scenario, Synthetic aperture radars (SAR......) have proven useful. In this study, SAR based dataset- ENVISAT ASAR has been used for Wind Atlas generation. Furthermore, a comparative study has been performed with Global Wind Atlas (GWA) to determine a potential offshore wind farm. Additionally, the annual energy production of that offshore windfarm...

  4. Amplitude modulation of wind turbine noise

    CERN Document Server

    Makarewicz, Rufin

    2013-01-01

    Due to swish and thump amplitude modulation, the noise of wind turbines cause more annoyance than other environmental noise of the same average level. The wind shear accounts for the thump modulation (van den Berg effect). Making use of the wind speed measurements at the hub height, as well as at the top and the bottom of the rotor disc (Fig.1), the non-standard wind profile is applied. It causes variations in the A-weighted sound pressure level, LpA. The difference between the maximum and minimum of LpA characterizes thump modulation (Fig.2).

  5. Wind Resource Assessment of Gujarat (India)

    Energy Technology Data Exchange (ETDEWEB)

    Draxl, C.; Purkayastha, A.; Parker, Z.

    2014-07-01

    India is one of the largest wind energy markets in the world. In 1986 Gujarat was the first Indian state to install a wind power project. In February 2013, the installed wind capacity in Gujarat was 3,093 MW. Due to the uncertainty around existing wind energy assessments in India, this analysis uses the Weather Research and Forecasting (WRF) model to simulate the wind at current hub heights for one year to provide more precise estimates of wind resources in Gujarat. The WRF model allows for accurate simulations of winds near the surface and at heights important for wind energy purposes. While previous resource assessments published wind power density, we focus on average wind speeds, which can be converted to wind power densities by the user with methods of their choice. The wind resource estimates in this study show regions with average annual wind speeds of more than 8 m/s.

  6. The wind speed profile at offshore wind farm sites

    Science.gov (United States)

    Lange, B.; Larsen, S. E.; Højstrup, J.; Barthelmie, R.

    2003-04-01

    a 50 m meteorological mast and an acoustic sea bed mounted wave gauge. Wind speed and turbulence intensity profiles are modelled for the Rødsand site using different approaches for stability and roughness. Results are compared with the measured data. For the sea surface roughness the use of the Charnock equation leads to good results. Improvements from using a wave field dependent roughness description are found to be small. For stability induced influences on the profiles M-O-theory works well in the case of unstable stratification. For stable stratification large deviations are found. They can be explained qualitatively as flow regimes with a mixed layer close to the surface and a capping inversion. In such a flow the atmospheric stability is strongly dependent on height and Monin-Obukhov similarity theory fails. For the Rødsand measurement this flow regime has been found to have an important influence on the wind climatology of the site. A wind speed at hub height predicted from a lower measurement with conventional theory will be underestimated. Højstrup, J.: Vertical Extrapolation of Offshore Wind Profiles. Wind energy for the next millennium. Proceedings. 1999 European wind energy conference (EWEC '99), Nice (FR), 1-5 Mar 1999. Petersen, E.L.; Hjuler Jensen, P.; Rave, K.; Helm, P.; Ehmann, H. (eds.), (1999) p. 1220-1223 Smedman, A.-S., H. Bergström and B. Grisogono: Evolution of stable internal boundary layers over a cold sea. Journal of Geophysical Research 102(C1), (1997); pp.1091-1099. Johnson, H.K., J. Højstrup, H.J. Vested, &S.E. Larsen: On the Dependence of Sea Surface Roughness on Wind Waves. Journal of Physical Oceanography. Vol.28 (1998) p. 1702-1716

  7. The Impact of Variable Wind Shear Coefficients on Risk Reduction of Wind Energy Projects.

    Science.gov (United States)

    Corscadden, Kenneth W; Thomson, Allan; Yoonesi, Behrang; McNutt, Josiah

    2016-01-01

    Estimation of wind speed at proposed hub heights is typically achieved using a wind shear exponent or wind shear coefficient (WSC), variation in wind speed as a function of height. The WSC is subject to temporal variation at low and high frequencies, ranging from diurnal and seasonal variations to disturbance caused by weather patterns; however, in many cases, it is assumed that the WSC remains constant. This assumption creates significant error in resource assessment, increasing uncertainty in projects and potentially significantly impacting the ability to control gird connected wind generators. This paper contributes to the body of knowledge relating to the evaluation and assessment of wind speed, with particular emphasis on the development of techniques to improve the accuracy of estimated wind speed above measurement height. It presents an evaluation of the use of a variable wind shear coefficient methodology based on a distribution of wind shear coefficients which have been implemented in real time. The results indicate that a VWSC provides a more accurate estimate of wind at hub height, ranging from 41% to 4% reduction in root mean squared error (RMSE) between predicted and actual wind speeds when using a variable wind shear coefficient at heights ranging from 33% to 100% above the highest actual wind measurement.

  8. IMPER: Characterization of the Wind Field over a Large Wind Turbine Rotor:Final report

    OpenAIRE

    Schmidt Paulsen, Uwe; Wagner, Rozenn

    2012-01-01

    A modern wind turbine rotor with a contemporary rotor size would easily with the tips penetrate the air between 116 m and 30 m and herby experience effects of different wind. With current rules on power performance measurements such as IEC 61400-121 the reference wind speed is measured at hub height, an oversimplification of the wind energy power over the rotor disk area is carried out. The project comprised a number of innovative and coordinated measurements on a full scale turbine with remo...

  9. Wind Turbine Power Curves Incorporating Turbulence Intensity

    DEFF Research Database (Denmark)

    Sørensen, Emil Hedevang Lohse

    2014-01-01

    The performance of a wind turbine in terms of power production (the power curve) is important to the wind energy industry. The current IEC-61400-12-1 standard for power curve evaluation recognizes only the mean wind speed at hub height and the air density as relevant to the power production....... However, numerous studies have shown that the power production depends on several variables, in particular turbulence intensity. This paper presents a model and a method that are computationally tractable and able to account for some of the influence of turbulence intensity on the power production...

  10. Improving Maryland’s Offshore Wind Energy Resource Estimate Using Doppler Wind Lidar Technology to Assess Microtmeteorology Controls

    Directory of Open Access Journals (Sweden)

    Pé Alexandra St.

    2016-01-01

    Compared to lidar measurements, power law extrapolation estimates and operational National Weather Service models underestimated hub-height wind speeds in the WEA. In addition, lidar observations suggest the frequent development of a low-level wind maximum (LLWM, with high turbinelayer wind shear and low turbulence intensity within a turbine’s rotor layer (40m-160m. Results elucidate the advantages of using Doppler wind lidar technology to improve offshore wind resource estimates and its ability to monitor under-sampled offshore meteorological controls impact on a potential turbine’s ability to produce power.

  11. Profile Tests to Optimize the Utilization of Wind Energy

    Directory of Open Access Journals (Sweden)

    KIRCSI, Andrea

    2008-01-01

    Full Text Available We have to know the property of air movement in hub height of wind turbine onunderstanding that we want to utilize of wind power economically. We can calculate wind speed fromnear ground measurement to hub height but always have mistake in results depend on applied method.In Hungary the Hungarian Meteorological Service carried out expedition wind measurements withSODAR equipment to study wind potential of the country within a frame of a scientific competition.We analysed SODAR data from Budapest, Paks and Szeged with statistical method looking for answerto our following question: How can frequency distributions of wind speed and wind direction indifferent height change? Are there any differences in form of wind profiles and in wind power indifferent wind direction sector? How can daily course of wind speed and potential of wind energy indifferent height change? At the same time, we suppose that there is a so-called “inflection altitude,”where the daily course of the wind speed and wind energy is random. We try to determine this altitudeon the basis of tower measurements in Paks. Finally we get an example to the distribution of specificwind power according to parts of the day.

  12. Modeling of the dynamics of wind to power conversion including high wind speed behavior

    DEFF Research Database (Denmark)

    Litong-Palima, Marisciel; Bjerge, Martin Huus; Cutululis, Nicolaos Antonio

    2016-01-01

    of power system studies, but the idea of the proposed wind turbine model is to include the main dynamic effects in order to have a better representation of the fluctuations in the output power and of the fast power ramping especially because of high wind speed shutdowns of the wind turbine. The high wind......This paper proposes and validates an efficient, generic and computationally simple dynamic model for the conversion of the wind speed at hub height into the electrical power by a wind turbine. This proposed wind turbine model was developed as a first step to simulate wind power time series...... for power system studies. This paper focuses on describing and validating the single wind turbine model, and is therefore neither describing wind speed modeling nor aggregation of contributions from a whole wind farm or a power system area. The state-of-the-art is to use static power curves for the purpose...

  13. Benefit Evaluation of Wind Turbine Generators in Wind Farms Using Capacity-Factor Analysis and Economic-Cost Methods

    DEFF Research Database (Denmark)

    Chen, Zhe; Wang, L.; Yeh, T-H.

    2009-01-01

    Due to the recent price spike of the international oil and the concern of global warming, the development and deployment of renewable energy become one of the most important energy policies around the globe. Currently, there are different capacities and hub heights for commercial wind turbine...... generators (WTGs). To fully capture wind energy, different wind farms (WFs) should select adequate capacity of WTGs to effectively harvest wind energy and maximize their economic benefit. To establish selection criterion, this paper first derives the equations for capacity factor (CF) and pairing performance...

  14. Some challenges of wind modelling for modern wind turbines: The Weibull distribution

    DEFF Research Database (Denmark)

    Gryning, Sven-Erik; Batchvarova, Ekatarina; Floors, Rogier;

    2012-01-01

    Wind power assessments, as well as forecast of wind energy production, are key issues in wind energy and grid related studies. However the hub height of today’s wind turbines is well above the surface layer. Wind profiles studies based on mast data show that the wind profile above the surface layer...... depends on the planetary boundary layer (PBL) structure and height, thus parameters that are not accounted for in today’s traditional applied flow simulation models and parameterizations. Here we report on one year of measurements of the wind profile performed by use of a long range wind lidar (WSL 70) up...... to a height of 600 meters with 50 meters resolution. The lidar is located at a flat coastal site. The applicability of the WRF model to predict some of the important parameters for wind energy has been investigated. In this presentation, some general results on the ability of WRF to predict the wind profile...

  15. Onshore wind energy in Baden-Württemberg: a bottom-up economic assessment of the socio-technical potential

    OpenAIRE

    2015-01-01

    Detailed information about the potentials and costs of renewable energies is an important input factor for energy system models, as well as commercial and political decision-making processes. With its increasing locally installed capacity and hub height, wind energy plays an important role when it comes to meeting climate targets and optimizing electricity networks. Recently however, wind energy has faced more and more social barriers and land use constraints which can negatively impact both ...

  16. Climatological attribution of wind power ramp events in East Japan and their probabilistic forecast based on multi-model ensembles downscaled by analog ensemble using self-organizing maps

    Science.gov (United States)

    Ohba, Masamichi; Nohara, Daisuke; Kadokura, Shinji

    2016-04-01

    Severe storms or other extreme weather events can interrupt the spin of wind turbines in large scale that cause unexpected "wind ramp events". In this study, we present an application of self-organizing maps (SOMs) for climatological attribution of the wind ramp events and their probabilistic prediction. The SOM is an automatic data-mining clustering technique, which allows us to summarize a high-dimensional data space in terms of a set of reference vectors. The SOM is applied to analyze and connect the relationship between atmospheric patterns over Japan and wind power generation. SOM is employed on sea level pressure derived from the JRA55 reanalysis over the target area (Tohoku region in Japan), whereby a two-dimensional lattice of weather patterns (WPs) classified during the 1977-2013 period is obtained. To compare with the atmospheric data, the long-term wind power generation is reconstructed by using a high-resolution surface observation network AMeDAS (Automated Meteorological Data Acquisition System) in Japan. Our analysis extracts seven typical WPs, which are linked to frequent occurrences of wind ramp events. Probabilistic forecasts to wind power generation and ramps are conducted by using the obtained SOM. The probability are derived from the multiple SOM lattices based on the matching of output from TIGGE multi-model global forecast to the WPs on the lattices. Since this method effectively takes care of the empirical uncertainties from the historical data, wind power generation and ramp is probabilistically forecasted from the forecasts of global models. The predictability skill of the forecasts for the wind power generation and ramp events show the relatively good skill score under the downscaling technique. It is expected that the results of this study provides better guidance to the user community and contribute to future development of system operation model for the transmission grid operator.

  17. WindScanner.eu - a new Remote Sensing Research Infrastructure for On- and Offshore Wind Energy

    DEFF Research Database (Denmark)

    Mikkelsen, Torben; Siggaard Knudsen, Søren; Sjöholm, Mikael

    2012-01-01

    will be disseminated throughout Europe to pilot European wind energy research centers. The new research infrastructure will become an open source infrastructure that also invites collaboration with wind energy related atmospheric scientists and wind energy industry overseas. Recent achievements with 3D Wind...... and a rotor diameter of 154 meters; hence its blade tips reaches almost 200 meters into the sky. The wind speed profiles over the rotor planes are consequently no longer representatively measured by a single cup anemometer at hub height from a nearby met-mast; power curve assessment as well as turbine control...... call for multi-height multi point measurement strategies of wind speed and wind shear within the turbines entire rotor plane. The development of our new remote sensing-based WindScanner.dk facility as well as the first measurement results obtained to date are here presented, including a first wind...

  18. Power curve report - with rotor equivalent wind speed

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here......, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...

  19. Estonian total ozone climatology

    Directory of Open Access Journals (Sweden)

    K. Eerme

    Full Text Available The climatological characteristics of total ozone over Estonia based on the Total Ozone Mapping Spectrometer (TOMS data are discussed. The mean annual cycle during 1979–2000 for the site at 58.3° N and 26.5° E is compiled. The available ground-level data interpolated before TOMS, have been used for trend detection. During the last two decades, the quasi-biennial oscillation (QBO corrected systematic decrease of total ozone from February–April was 3 ± 2.6% per decade. Before 1980, a spring decrease was not detectable. No decreasing trend was found in either the late autumn ozone minimum or in the summer total ozone. The QBO related signal in the spring total ozone has an amplitude of ± 20 DU and phase lag of 20 months. Between 1987–1992, the lagged covariance between the Singapore wind and the studied total ozone was weak. The spring (April–May and summer (June–August total ozone have the best correlation (coefficient 0.7 in the yearly cycle. The correlation between the May and August total ozone is higher than the one between the other summer months. Seasonal power spectra of the total ozone variance show preferred periods with an over 95% significance level. Since 1986, during the winter/spring, the contribution period of 32 days prevails instead of the earlier dominating 26 days. The spectral densities of the periods from 4 days to 2 weeks exhibit high interannual variability.

    Key words. Atmospheric composition and structure (middle atmosphere – composition and chemistry; volcanic effects – Meteorology and atmospheric dynamics (climatology

  20. INL Wind Farm Project Description Document

    Energy Technology Data Exchange (ETDEWEB)

    Gary Siefert

    2009-07-01

    The INL Wind Farm project proposes to install a 20 MW to 40 MW wind farm on government property, consisting of approximately ten to twenty full-sized (80-meter hub height) towers with 2 MW turbines, and access roads. This includes identifying the optimal turbine locations, building access roads, and pouring the tower foundations in preparation for turbine installation. The project successfully identified a location on INL lands with commercially viable wind resources (i.e., greater than 11 mph sustained winds) for a 20 to 40 MW wind farm. Additionally, the proposed Wind Farm was evaluated against other General Plant Projects, General Purpose Capital Equipment projects, and Line Item Construction Projects at the INL to show the relative importance of the proposed Wind Farm project.

  1. Validation of Sodar Measurements for Wind Power

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose

    2006-01-01

    A ground-based SODAR has been tested for 1½ years together with a traditional measurement set-up consisting of cups and vanes for measuring wind data for wind power assessment at a remote location. Many problems associated to the operation of a remote located SODAR have been solved during...... the project and a new remote power system has been designed. A direct comparison between SODAR and cup measurements revealed a limitation for the SODAR measurements during different weather conditions, especially since the SODAR was not able to measure wind speeds above 15 m/s due to an increasing back......-ground noise. Instead, using the SODAR as a profiler to establish representative wind speed profiles was successful. These wind speed profiles are combined with low height reference measurements to establish reliable hub height wind speed distributions. Representative wind speed profiles can be establish...

  2. Characterization of wind power resource in the United States

    Directory of Open Access Journals (Sweden)

    U. B. Gunturu

    2012-10-01

    Full Text Available Wind resource in the continental and offshore United States has been reconstructed and characterized using metrics that describe, apart from abundance, its availability, persistence and intermittency. The Modern Era Retrospective-Analysis for Research and Applications (MERRA boundary layer flux data has been used to construct wind profile at 50 m, 80 m, 100 m, 120 m turbine hub heights. The wind power density (WPD estimates at 50 m are qualitatively similar to those in the US wind atlas developed by the National Renewable Energy Laboratory (NREL, but quantitatively a class less in some regions, but are within the limits of uncertainty. The wind speeds at 80 m were quantitatively and qualitatively close to the NREL wind map. The possible reasons for overestimation by NREL have been discussed. For long tailed distributions like those of the WPD, the mean is an overestimation and median is suggested for summary representation of the wind resource.

    The impact of raising the wind turbine hub height on metrics of abundance, persistence, variability and intermittency is analyzed. There is a general increase in availability and abundance of wind resource but there is an increase in intermittency in terms of level crossing rate in low resource regions.

  3. Wind Power Curve Modeling in Simple and Complex Terrain

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wharton, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Irons, Z. [Enel Green Power North America, Andover, MA (United States); Qualley, G. [Pentalum, Colleyville, TX (United States)

    2015-02-09

    Our previous work on wind power curve modeling using statistical models focused on a location with a moderately complex terrain in the Altamont Pass region in northern California (CA). The work described here is the follow-up to that work, but at a location with a simple terrain in northern Oklahoma (OK). The goal of the present analysis was to determine the gain in predictive ability afforded by adding information beyond the hub-height wind speed, such as wind speeds at other heights, as well as other atmospheric variables, to the power prediction model at this new location and compare the results to those obtained at the CA site in the previous study. While we reach some of the same conclusions at both sites, many results reported for the CA site do not hold at the OK site. In particular, using the entire vertical profile of wind speeds improves the accuracy of wind power prediction relative to using the hub-height wind speed alone at both sites. However, in contrast to the CA site, the rotor equivalent wind speed (REWS) performs almost as well as the entire profile at the OK site. Another difference is that at the CA site, adding wind veer as a predictor significantly improved the power prediction accuracy. The same was true for that site when air density was added to the model separately instead of using the standard air density adjustment. At the OK site, these additional variables result in no significant benefit for the prediction accuracy.

  4. Improving Maryland's Offshore Wind Energy Resource Estimate Using Doppler Wind Lidar Technology to Assess Microtmeteorology Controls

    Science.gov (United States)

    St. Pé, Alexandra; Wesloh, Daniel; Antoszewski, Graham; Daham, Farrah; Goudarzi, Navid; Rabenhorst, Scott; Delgado, Ruben

    2016-06-01

    There is enormous potential to harness the kinetic energy of offshore wind and produce power. However significant uncertainties are introduced in the offshore wind resource assessment process, due in part to limited observational networks and a poor understanding of the marine atmosphere's complexity. Given the cubic relationship between a turbine's power output and wind speed, a relatively small error in the wind speed estimate translates to a significant error in expected power production. The University of Maryland Baltimore County (UMBC) collected in-situ measurements offshore, within Maryland's Wind Energy Area (WEA) from July-August 2013. This research demonstrates the ability of Doppler wind lidar technology to reduce uncertainty in estimating an offshore wind resource, compared to traditional resource assessment techniques, by providing a more accurate representation of the wind profile and associated hub-height wind speed variability. The second objective of this research is to elucidate the impact of offshore micrometeorology controls (stability, wind shear, turbulence) on a turbine's ability to produce power. Compared to lidar measurements, power law extrapolation estimates and operational National Weather Service models underestimated hub-height wind speeds in the WEA. In addition, lidar observations suggest the frequent development of a low-level wind maximum (LLWM), with high turbinelayer wind shear and low turbulence intensity within a turbine's rotor layer (40m-160m). Results elucidate the advantages of using Doppler wind lidar technology to improve offshore wind resource estimates and its ability to monitor under-sampled offshore meteorological controls impact on a potential turbine's ability to produce power.

  5. Atmospheric stability and its influence on wind turbine loads

    DEFF Research Database (Denmark)

    Sathe, Ameya; Mann, Jakob; Barlas, Thanasis K.;

    2012-01-01

    Simulations of wind turbine loads for the NREL 5 MW reference wind turbine under diabatic wind conditions are performed for mean wind speeds between 3 { 16 m/s at the turbine hub height. The loads are quantified as the cumulative sum of the damage equivalent load for different wind speeds...... that are weighted according to the wind speed and stability distribution. It is observed that atmospheric stability influences the tower and rotor loads. The difference in the calculated tower loads using diabatic wind conditions and those obtained assuming neutral conditions only is approximately 16%, whereas...... the difference for the rotor loads is up to 11%. The blade loads are hardly influenced by atmospheric stability, where the difference between the calculated loads using diabatic and neutral input wind conditions is less than 1%. The wind profiles and turbulence under diabatic conditions have contrasting...

  6. Los Alamos Climatology 2016 Update

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, David Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-10

    The Los Alamos National Laboratory (LANL or the Laboratory) operates a meteorology monitoring network to support LANL emergency response, engineering designs, environmental compliance, environmental assessments, safety evaluations, weather forecasting, environmental monitoring, research programs, and environmental restoration. Weather data has been collected in Los Alamos since 1910. Bowen (1990) provided climate statistics (temperature and precipitation) for the 1961– 1990 averaging period, and included other analyses (e.g., wind and relative humidity) based on the available station locations and time periods. This report provides an update to the 1990 publication Los Alamos Climatology (Bowen 1990).

  7. Hanford Site Climatological Summary 2004 with Historical Data

    Energy Technology Data Exchange (ETDEWEB)

    Hoitink, Dana J.; Burk, Kenneth W.; Ramsdell, James V.; Shaw, William J.

    2005-06-03

    This document presents the climatological data measured on the DOE Hanford Site for calendar year 2004. This report contains updated historical information for temperature, precipitation, wind, and normal and extreme values of temperature, and precipitation.

  8. Quadrennial Technology Review 2015: Technology Assessments--Wind Power

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2015-10-07

    Wind power has become a mainstream power source in the U.S. electricity portfolio, supplying 4.9% of the nation’s electricity demand in 2014. With more than 65 GW installed across 39 states at the end of 2014, utility-scale wind power is a cost-effective source of low-emissions power generation throughout much of the nation. The United States has significant sustainable land-based and offshore wind resource potential, greater than 10 times current total U.S. electricity consumption. A technical wind resource assessment conducted by the Department of Energy (DOE) in 2009 estimated that the land-based wind energy potential for the contiguous United States is equivalent to 10,500 GW capacity at 80 meters (m) hub and 12,000 GW capacity at 100 meters (m) hub heights, assuming a capacity factor of at least 30%. A subsequent 2010 DOE report estimated the technical offshore wind energy potential to be 4,150 GW. The estimate was calculated from the total offshore area within 50 nautical miles of shore in areas where average annual wind speeds are at least 7 m per second at a hub height of 90 m.

  9. Using machine learning to predict wind turbine power output

    Science.gov (United States)

    Clifton, A.; Kilcher, L.; Lundquist, J. K.; Fleming, P.

    2013-06-01

    Wind turbine power output is known to be a strong function of wind speed, but is also affected by turbulence and shear. In this work, new aerostructural simulations of a generic 1.5 MW turbine are used to rank atmospheric influences on power output. Most significant is the hub height wind speed, followed by hub height turbulence intensity and then wind speed shear across the rotor disk. These simulation data are used to train regression trees that predict the turbine response for any combination of wind speed, turbulence intensity, and wind shear that might be expected at a turbine site. For a randomly selected atmospheric condition, the accuracy of the regression tree power predictions is three times higher than that from the traditional power curve methodology. The regression tree method can also be applied to turbine test data and used to predict turbine performance at a new site. No new data are required in comparison to the data that are usually collected for a wind resource assessment. Implementing the method requires turbine manufacturers to create a turbine regression tree model from test site data. Such an approach could significantly reduce bias in power predictions that arise because of the different turbulence and shear at the new site, compared to the test site.

  10. IMPER: Characterization of the wind field over a large wind turbine rotor - final report; Improved performance

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt Paulsen, U.; Wagner, R.

    2012-01-15

    A modern wind turbine rotor with a contemporary rotor size would easily with the tips penetrate the air between 116 m and 30 m and herby experience effects of different wind. With current rules on power performance measurements such as IEC 61400-121 the reference wind speed is measured at hub height, an oversimplification of the wind energy power over the rotor disk area is carried out. The project comprised a number of innovative and coordinated measurements on a full scale turbine with remote sensing technology and simulations on a 500 kW wind turbine for the effects of wind field characterization. The objective with the present report is to give a short overview of the different experiments carried out and results obtained within the final phase of this project. (Author)

  11. Wind/solar resource in Texas

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, V.; Starcher, K.; Gaines, H. [West Texas A& M Univ., Canyon, TX (United States)

    1997-12-31

    Data are being collected at 17 sites to delineate a baseline for the wind and solar resource across Texas. Wind data are being collected at 10, 25, and 40 m (in some cases at 50 m) to determine wind shear and power at hub heights of large turbines. Many of the sites are located in areas of predicted terrain enhancement. The typical day in a month for power and wind turbine output was calculated for selected sites and combination of sites; distributed systems. Major result to date is that there is the possibility of load matching in South Texas during the summer months, even though the average values by month indicate a low wind potential.

  12. Wind energy availability above gaps in a forest

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Mann, Jakob; Dellwik, Ebba

    2009-01-01

    There is a lack of data on availability of wind energy above a forest disturbed by clear-cuts, where a wind energy developer may find an opportunity to install a wind farm. Computational fluid dynamics (CFD) models can provide spatial patterns of wind and turbulence, and help to develop optimal...... installation strategies. The canopy-planetary boundary-layer model SCADIS is used to investigate the effect of forest gap size (within the diameter range of 3 - 75 tree heights, h) on wind energy related variables. A wind turbine was assumed with following features: the hub height and rotor diameter of 3.5h...... were estimated from modelled data. The results show that the effect of the forest gaps with diameters smaller than 55h on wind energy captured by the assumed wind turbine and located in the centre of round low-roughness gap is practically insignificant. The high level of spatial variation of considered...

  13. A numerical study on the responses of the South China Sea upper circulation to different climatological wind products%南海上层环流对不同气候态风场响应的数值研究

    Institute of Scientific and Technical Information of China (English)

    闫桐; 齐义泉; 经志友

    2015-01-01

    Four kinds of climatological monthly wind stresses, including SCOW (Scatterometer Climatology of Ocean Winds), CFSR (NCEP Climate Forecast System Reanalysis), ERA-Interim (the Interim ECMWF Re-Analysis), and NCEP [the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) Reanalysis 1] were used to force the South China Sea (SCS) circulation using the Regional Ocean Modeling System (ROMS). The differences among the simulated upper circulation in the SCS from the four experiments and their dynamical relationships with the differences of these wind stresses were explored. Significant differences exist in wind stress and its curl in terms of patterns, and these differences are reflected in the upper-ocean model responses. The results show that seasonal variation of the basin-scale circulation in the SCS can be well represented in all the experiments. The major differences are in sub-basin or mesoscale circulations. It is the significant local positive wind stress curl that leads to the generation of the Luzon cold eddy in winter. The dipole structure of the upper circulation off the Vietnam coast can be clearly seen in all four experiments in summer;but the strength of the dipole varies with the forcing and is related to the local wind stress curl dipole. Moreover, it is shown that the Luzon Strait transports are consistent in the experiments, which indicates that there is little impact from the differences of local wind stresses on the Luzon Strait transport. But the simulated Taiwan Strait transports differ great in both autumn and winter. Strong northeasterly wind impedes the water transport from south to north. Further analysis shows that large northward seawater transport through the Taiwan Strait in winter is in favor of the existence of the SCS warm current (SCSWC) in the northern SCS in the model results. Overall, this study helps us to more deeply understand the responses of upper-ocean circulation in the SCS to

  14. The use of real-time off-site observations as a methodology for increasing forecast skill in prediction of large wind power ramps one or more hours ahead of their impact on a wind plant.

    Energy Technology Data Exchange (ETDEWEB)

    Martin Wilde, Principal Investigator

    2012-12-31

    ABSTRACT Application of Real-Time Offsite Measurements in Improved Short-Term Wind Ramp Prediction Skill Improved forecasting performance immediately preceding wind ramp events is of preeminent concern to most wind energy companies, system operators, and balancing authorities. The value of near real-time hub height-level wind data and more general meteorological measurements to short-term wind power forecasting is well understood. For some sites, access to onsite measured wind data - even historical - can reduce forecast error in the short-range to medium-range horizons by as much as 50%. Unfortunately, valuable free-stream wind measurements at tall tower are not typically available at most wind plants, thereby forcing wind forecasters to rely upon wind measurements below hub height and/or turbine nacelle anemometry. Free-stream measurements can be appropriately scaled to hub-height levels, using existing empirically-derived relationships that account for surface roughness and turbulence. But there is large uncertainty in these relationships for a given time of day and state of the boundary layer. Alternatively, forecasts can rely entirely on turbine anemometry measurements, though such measurements are themselves subject to wake effects that are not stationary. The void in free-stream hub-height level measurements of wind can be filled by remote sensing (e.g., sodar, lidar, and radar). However, the expense of such equipment may not be sustainable. There is a growing market for traditional anemometry on tall tower networks, maintained by third parties to the forecasting process (i.e., independent of forecasters and the forecast users). This study examines the value of offsite tall-tower data from the WINDataNOW Technology network for short-horizon wind power predictions at a wind farm in northern Montana. The presentation shall describe successful physical and statistical techniques for its application and the practicality of its application in an operational

  15. Historical Climatology Series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Historical Climatology Series (HCS) is a set of climate-related publications published by NOAA's National Climatic Data Center beginning in 1978. HCS is...

  16. Preliminary Monthly Climatological Summaries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary Local Climatological Data, recorded since 1970 on Weather Burean Form 1030 and then National Weather Service Form F-6. The preliminary climate data pages...

  17. Global Synoptic Climatology Network

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Global Synoptic Climatology Network is a digital data set archived at the National Climatic Data Center (NCDC). This record combines the various types of data that...

  18. Climatological Data National Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The CDNS was published from 1950 - 1980. Monthly and annual editions contain summarized climatological information from the following publications: Local...

  19. Climatological Services Memorandums

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Climatological Services Memorandums were a series of memoranda issued by the Weather Bureau for the purpose of keeping all stations informed on the status and...

  20. Reference Climatological Stations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Reference Climatological Stations (RCS) network represents the first effort by NOAA to create and maintain a nationwide network of stations located only in areas...

  1. Lake Michigan Offshore Wind Feasibility Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Boezaart, Arnold [GVSU; Edmonson, James [GVSU; Standridge, Charles [GVSU; Pervez, Nahid [GVSU; Desai, Neel [University of Michigan; Williams, Bruce [University of Delaware; Clark, Aaron [GVSU; Zeitler, David [GVSU; Kendall, Scott [GVSU; Biddanda, Bopi [GVSU; Steinman, Alan [GVSU; Klatt, Brian [Michigan State University; Gehring, J. L. [Michigan State University; Walter, K. [Michigan State University; Nordman, Erik E. [GVSU

    2014-06-30

    The purpose of this project was to conduct the first comprehensive offshore wind assessment over Lake Michigan and to advance the body of knowledge needed to support future commercial wind energy development on the Great Lakes. The project involved evaluation and selection of emerging wind measurement technology and the permitting, installation and operation of the first mid-lake wind assessment meteorological (MET) facilities in Michigan’s Great Lakes. In addition, the project provided the first opportunity to deploy and field test floating LIDAR and Laser Wind Sensor (LWS) technology, and important research related equipment key to the sitting and permitting of future offshore wind energy development in accordance with public participation guidelines established by the Michigan Great Lakes Wind Council (GLOW). The project created opportunities for public dialogue and community education about offshore wind resource management and continued the dialogue to foster Great Lake wind resource utilization consistent with the focus of the GLOW Council. The technology proved to be effective, affordable, mobile, and the methods of data measurement accurate. The public benefited from a substantial increase in knowledge of the wind resources over Lake Michigan and gained insights about the potential environmental impacts of offshore wind turbine placements in the future. The unique first ever hub height wind resource assessment using LWS technology over water and development of related research data along with the permitting, sitting, and deployment of the WindSentinel MET buoy has captured public attention and has helped to increase awareness of the potential of future offshore wind energy development on the Great Lakes. Specifically, this project supported the acquisition and operation of a WindSentinel (WS) MET wind assessment buoy, and associated research for 549 days over multiple years at three locations on Lake Michigan. Four research objectives were defined for the

  2. The influence of humidity fluxes on offshore wind speed profiles

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Sempreviva, Anna Maria; Pryor, Sara

    2010-01-01

    Wind energy developments offshore focus on larger turbines to keep the relative cost of the foundation per MW of installed capacity low. Hence typical wind turbine hub-heights are extending to 100 m and potentially beyond. However, measurements to these heights are not usually available, requiring...... extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshore, deviations from the traditional logarithmic wind speed profile become significant and stability corrections are required. This research focuses on quantifying the effect of humidity fluxes on stability corrected...... wind speed profiles. The effect on wind speed profiles is found to be important in stable conditions where including humidity fluxes forces conditions towards neutral. Our results show that excluding humidity fluxes leads to average predicted wind speeds at 150 m from 10 m which are up to 4% higher...

  3. The influence of humidity fluxes on offshore wind speed profiles

    Directory of Open Access Journals (Sweden)

    R. J. Barthelmie

    2010-05-01

    Full Text Available Wind energy developments offshore focus on larger turbines to keep the relative cost of the foundation per MW of installed capacity low. Hence typical wind turbine hub-heights are extending to 100 m and potentially beyond. However, measurements to these heights are not usually available, requiring extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshore, deviations from the traditional logarithmic wind speed profile become significant and stability corrections are required. This research focuses on quantifying the effect of humidity fluxes on stability corrected wind speed profiles. The effect on wind speed profiles is found to be important in stable conditions where including humidity fluxes forces conditions towards neutral. Our results show that excluding humidity fluxes leads to average predicted wind speeds at 150 m from 10 m which are up to 4% higher than if humidity fluxes are included, and the results are not very sensitive to the method selected to estimate humidity fluxes.

  4. LIDAR wind speed measurements at a Taiwan onshore wind park

    Science.gov (United States)

    Wu, Yu-Ting; Lin, Ta-Hui; Hsuan, Chung-Yao; Li, Yu-Cheng; Yang, Ya-Fei; Tai, Tzy-Hwan; Huang, Chien-Cheng

    2016-04-01

    Measurements of wind speed and wind direction were carried out using a Leosphere Windcube LIDAR system at a Taiwan onshore wind park. The Lidar shot a total of five laser beams to the atmosphere to collect the light-of-sight (LOS) velocity. Four beams were sent successively in four cardinal directions along a 28° scanning cone angle, followed by a fifth, vertical beam. An unchangeable sampling rate of approximately 1.2 Hz was set in the LIDAR system to collect the LOS velocity. The supervisory control and data acquisition (SCADA) data from two GE 1.5 MW wind turbines near the LIDAR deployment site were acquired for the whole measuring period from February 4 to February 16 of 2015. The SCADA data include the blade angular velocity, the wind velocity measured at hub height from an anemometer mounted on the nacelle, the wind turbine yaw angle, and power production; each parameter was recorded as averages over 1-min periods. The data analysis involving the LIDAR measurements and the SCADA data were performed to obtain the turbulent flow statistics. The results show that the turbine power production has significant dependence to the wind speed, wind direction, turbulence intensity and wind shear.

  5. Offshore and onshore wind turbine wake meandering studied in an ABL wind tunnel

    DEFF Research Database (Denmark)

    Barlas, Emre; Buckingham, Sophia; Glabeke, Gertjan;

    2015-01-01

    diameter downstream. The results show an earlier wake recovery for the onshore case. The effect of inflow conditions and the wind turbine’s working conditions on wake meandering was investigated. Wake meandering was detected by hot wire anemometry through a low frequency peak in the turbulent power......Scaled wind turbine models have been installed in the VKI L1-B atmospheric boundary layer wind tunnel at offshore and onshore conditions. Time-resolved measurements were carried out with three component hot wire anemometry and stereo-PIV in the middle vertical plane of the wake up to eleven turbine...... spectrum, present in the entire wake mainly for offshore inflow condition. It was found that the Strouhal number, based on the rotor diameter and the wind velocity at hub height, was in the order of 0.25. Below the meandering frequency, turbulence power spectrum decreased, whereas above it increased. Wake...

  6. A climatology of the F-layer equivalent winds derived from ionosonde measurements over two decades along the 120°-150°E sector

    Directory of Open Access Journals (Sweden)

    X. Luan

    2004-09-01

    Full Text Available The vertical equivalent winds (VEWs at the F-layer are analyzed along the 120°-150°E longitude sector with an emphasis on their latitudinal dependence. The VEWs are derived from the monthly median data of fourteen ionosonde stations over two decades. The results show that the VEWs have considerable dependences on the magnetic latitude with an approximate symmetry about the magnetic equator. They are mostly controlled by the electric field drifts in the magnetic equatorial region, and shift to be mostly contributed by neutral winds at mid-latitudes. The relative contribution of the two dynamic factors is regulated by the magnetic dip in addition to their own magnitudes. The VEWs generally have opposite directions and different magnitudes between lower and higher latitudes. At solar minimum, the magnitudes of VEWs are only between -20 and 20m/s at lower latitudes, while at higher latitudes they tend to increase with latitudes, typically having magnitudes between 20-40m/s. At solar maximum, the VEWs are reduced by about 10-20m/s in magnitudes during some local times at higher latitudes. A tidal analysis reveals that the relative importance of major tidal components is also different between lower and higher latitudes.

    The VEWs also depend on local time, season and solar activity. At higher latitudes, the nighttime VEWs have larger magnitude during post-midnight hours and so do the daytime ones before midday. The VEWs tend to have an inverse relationship with solar activity not only at night, but also by day, which is different from the meridional winds predicted by the HWM93 model. The latitudinal dependence of VEWs has two prevailing trends: one is a maximum at the highest latitudes (as far as the latitudes concerned in the present work; the other is a mid-latitude maximum. These two latitudinal trends are mostly dependent on season, while they depend relatively weakly on local time and solar activity. The

  7. Wake effects in Alsvik wind park: Comparison between measurements and predictions

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, Mikael [Uppsala Univ. (Sweden). Dept. of Meteorology; Rados, K.G.; Pothou, K.P. [National Technical Univ., Athen (Greece). Fluid section

    1996-12-01

    In this paper characteristic parameters in a wind turbine wake are studied. The data used are full-scale measurements from a wind farm in Sweden, Alsvik, and results from a numerical model calculated for the same site. The results are valid for neutral stratification. The model employs a particle-vortex approach at the rotor plane, a Navier-Stokes solver in the near wake and applies self preservation in the far wake. The parameters investigated are the relative velocity deficit at centre line and hub height, and the radial distribution of the turbulent kinetic energy. 6 refs, 9 figs

  8. Focused-based multifractal analysis of the wake in a wind turbine array utilizing proper orthogonal decomposition

    Science.gov (United States)

    Kadum, Hawwa; Ali, Naseem; Cal, Raúl

    2016-11-01

    Hot-wire anemometry measurements have been performed on a 3 x 3 wind turbine array to study the multifractality of the turbulent kinetic energy dissipations. A multifractal spectrum and Hurst exponents are determined at nine locations downstream of the hub height, and bottom and top tips. Higher multifractality is found at 0.5D and 1D downstream of the bottom tip and hub height. The second order of the Hurst exponent and combination factor show an ability to predict the flow state in terms of its development. Snapshot proper orthogonal decomposition is used to identify the coherent and incoherent structures and to reconstruct the stochastic velocity using a specific number of the POD eigenfunctions. The accumulation of the turbulent kinetic energy in top tip location exhibits fast convergence compared to the bottom tip and hub height locations. The dissipation of the large and small scales are determined using the reconstructed stochastic velocities. The higher multifractality is shown in the dissipation of the large scale compared to small-scale dissipation showing consistency with the behavior of the original signals.

  9. Gusts and Shear Within Hurricane Eyewalls Can Exceed Offshore Wind-Turbine Design Standards

    CERN Document Server

    Worsnop, Rochelle P; Bryan, George H; Damiani, Rick; Musial, Walt

    2016-01-01

    Offshore wind energy development is underway in the U.S., with proposed sites located in hurricane-prone regions. Turbine design criteria outlined by the International Electrotechnical Commission do not encompass the extreme wind speeds and directional shifts of hurricanes stronger than a Category 2. We examine the most turbulent portion of a hurricane (the eyewall) using large-eddy simulations with Cloud Model 1 (CM1). Gusts and mean wind speeds near the eyewall exceed the current design threshold of 50 m s-1 mean wind and 70 m s-1 gusts for Class I turbines. Gust factors are greatest at the eye-eyewall interface. Further, shifts in wind direction at wind turbine hub height suggest turbines must rotate into the wind faster than current practice. Although current design standards omit mention of wind direction change across the rotor layer, large values (15-50 deg) suggest that veer should be considered in design standards.

  10. Accounting for the speed shear in wind turbine power performance measurement

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Courtney, Michael; Gottschall, Julia

    2011-01-01

    The current IEC standard for wind turbine power performance measurement only requires measurement of the wind speed at hub height assuming this wind speed to be representative for the whole rotor swept area. However, the power output of a wind turbine depends on the kinetic energy flux, which...... itself depends on the wind speed profile, especially for large turbines. Therefore, it is important to characterize the wind profile in front of the turbine, and this should be preferably achieved by measuring the wind speed over the vertical range between lower and higher rotor tips. In this paper, we...... describe an experiment in which wind speed profiles were measured in front of a multimegawatt turbine using a ground–based pulsed lidar. Ignoring the vertical shear was shown to overestimate the kinetic energy flux of these profiles, in particular for those deviating significantly from a power law profile...

  11. Compressed air energy storage system reservoir size for a wind energy baseload power plant

    Energy Technology Data Exchange (ETDEWEB)

    Cavallo, A.J.

    1996-12-31

    Wind generated electricity can be transformed from an intermittent to a baseload resource using an oversized wind farm in conjunction with a compressed air energy storage (CAES) system. The size of the storage reservoir for the CAES system (solution mined salt cavern or porous media) as a function of the wind speed autocorrelation time (C) has been examined using a Monte Carlo simulation for a wind class 4 (wind power density 450 W m{sup -2} at 50 m hub height) wind regime with a Weibull k factor of 2.5. For values of C typically found for winds over the US Great Plains, the storage reservoir must have a 60 to 80 hour capacity. Since underground reservoirs account for only a small fraction of total system cost, this larger storage reservoir has a negligible effect on the cost of energy from the wind energy baseload system. 7 refs., 2 figs., 1 tab.

  12. Local Climatological Data ACSII Format

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Comma-delimited text files used to create the Local Climatological Data PDF files found in the Local Climatological Data library. Period of record begins in 1998,...

  13. Verification of the Prediction Accuracy of Annual Energy Output at Noma Wind Park by the Non-Stationary and Non-Linear Wind Synopsis Simulator, RIAM-COMPACT

    Science.gov (United States)

    Uchida, Takanori; Ohya, Yuji

    In the present study, the hub-height wind speed ratios for 16 individual wind directional groups were estimated by the RIAM-COMPACT for Noma Wind Park, Kagoshima Prefecture. The validity of the proposed estimation technique for the actual wind was examined. For this procedure, field observational data from the one year period between April, 2004 and March, 2005 were studied. In this case, the relative error on the prediction accuracy was less than 10% and less than 5% for the monthly and annual average wind speeds, respectively. Similar to the results for the annual average wind speed, the difference in the selected reference points (Wind Turbines #4 and #6) had little difference in the relative error on the prediction accuracy of the annual energy output. For both reference points, the relative error was within 10%.

  14. Gradient-Based Optimization of Wind Farms with Different Turbine Heights: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, Andrew P. J.; Thomas, Jared; Ning, Andrew; Annoni, Jennifer; Dykes, Katherine; Fleming, Paul

    2017-05-08

    Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5%-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and a low wind shear exponent.

  15. Hydrogen generation from small-scale wind-powered electrolysis system in different power matching modes

    Energy Technology Data Exchange (ETDEWEB)

    Goekcek, Murat [Department of Mechanical Engineering, Faculty of Engineering, Nigde University, Campus, 51100 Nigde (Turkey)

    2010-10-15

    This study presents a techno-economic evaluation on hydrogen generation from a small-scale wind-powered electrolysis system in different power matching modes. For the analysis, wind speed data, which measured as hourly time series in Kirklareli, Turkey, were used to predict the electrical energy and hydrogen produced by the wind-hydrogen energy system and their variation according to the height of the wind turbine. The system considered in this study is primarily consisted of a 6 kW wind-energy conversion system and a 2 kW PEM electrolyzer. The calculation of energy production was made by means of the levelized cost method by considering two different systems that are the grid-independent system and the grid-integrated system. Annual production of electrical energy and hydrogen was calculated as 15,148.26 kWh/year and 102.37 kg/year, respectively. The highest hydrogen production is obtained in January. The analyses showed that both electrical energy and hydrogen production depend strongly on the hub height of wind turbine in addition to the economic indicators. In the grid-integrated system, the calculated levelized cost of hydrogen changes in the range of 0.3485-4.4849 US$/kg for 36 m hub height related to the specific turbine cost. The grid-integrated system can be considered as profitable when the excess electrical energy delivered by system sold to the grid. (author)

  16. Wind Energy Potential in Bangladesh

    Directory of Open Access Journals (Sweden)

    A.Z.A. Saifullah

    2016-07-01

    Full Text Available Bangladesh is encountering difficulties in supplying energy to maintain its economic growth. Government of Bangladesh is looking for renewable energy sources to meet up the total power demand in this country. The present study aims to assess wind energy potential in Bangladesh as a sustainable solution to overcome the energy crisis. Wind speed at six coastal zones Patenga, Cox’s Bazar, Teknaf, Char Fassion, Kuakata and Kutubdia at Bay of Bengal of Bangladesh have been analyzed. A near shore wind farm has been considered at these locations having a coastal line of 574 km. The turbines are spaced 7D apart in the prevailing wind direction, and 3D apart in the perpendicular direction, where D is rotor diameter. This near shore wind farm with an array of 5104 horizontal axis wind turbines with hub height of 100 m and rotor diameter of 75 m with a wind speed of 7 m/sec is capable to generate 1855.25 MW of electrical power. This can mitigate 55.93 per cent of energy shortage in 2016. By developing renewable energy sources it is possible to compensate 11.25 per cent of total power demand by 2020.

  17. Wind resource characterization in the Arabian Peninsula

    KAUST Repository

    Yip, Chak Man Andrew

    2015-12-28

    Wind energy is expected to contribute to alleviating the rise in energy demand in the Middle East that is driven by population growth and industrial development. However, variability and intermittency in the wind resource present significant challenges to grid integration of wind energy systems. These issues are rarely addressed in the literature of wind resource assessment in the Middle East due to sparse meteorological observations with varying record lengths. In this study, the wind field with consistent space–time resolution for over three decades at three hub heights (50m, 80m, 140m) over the whole Arabian Peninsula is constructed using the Modern Era Retrospective-Analysis for Research and Applications (MERRA) dataset. The wind resource is assessed at a higher spatial resolution with metrics of temporal variations in the wind than in prior studies. Previously unrecognized locations of interest with high wind abundance and low variability and intermittency have been identified in this study and confirmed by recent on-site observations. In particular, the western mountains of Saudi Arabia experience more abundant wind resource than most Red Sea coastal areas. The wind resource is more variable in coastal areas along the Arabian Gulf than their Red Sea counterparts at a similar latitude. Persistent wind is found along the coast of the Arabian Gulf.

  18. Wind turbines - facts from 20 years of technological progress

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, L.H.; Dannemand Andersen, P. [Risoe Ntaional Lab., Roskilde (Denmark)

    1999-03-01

    The first Danish commercial wind turbines were installed in the late 1970s. Over the last 20 years the Danish wind turbine market has been relatively stable concerning annual installations, and the wind turbine technology has been able to develop continuously. This gives a unique time track for technology analysts. The aim of this paper is to extract reliable information on this time track from existing archives and statistics. Seven generations of wind turbine technology have been identified mainly based on `characteristic` rotor diameters. The technological development of each generation is described using indicators such as: market share in Denmark, generator size, rotor diameter, hub height, electricity production and productivity. Economical indicators comprise: costs of turbine and standard foundation. (au)

  19. Climatology of local flow patterns around Basel

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Recently a method has been developed to classify local-scale flow patterns from the wind measurements at a dense network of stations. It was found that in the MISTRAL area around Basel a dozen characteristic flow patterns occur. However, as the dense network of stations ran only during one year, no reliable climatology can be inferred from these data, especially the annual cycle of the flow patterns is not well determined from a single year of observations. As there exist several routinely operated stations in and near the MISTRAL area, a method was searched to identify the local flow patterns from the observations at the few routine stations. A linear discriminant analysis turned out to be the best method. Based of data from 11 stations which were simultaneously operated during 1990-1995 a six-year climatology of the flow patterns could be obtained. (author) 1 fig., 1 tab., 3 refs.

  20. A climatological network for regional climate monitoring in Sardinia.

    Science.gov (United States)

    Delitala, Alessandro M. S.

    2016-04-01

    In recent years the Region of Sardinia has been working to set-up a Regional Climatological Network of surface stations, in order to monitor climate (either stationary or changing) at sub-synoptic scale and in order to make robust climatological information available to researchers and to local stake-holders. In order to do that, an analysis of long climatological time series has been performed on the different historical networks of meteorological stations that existed over the past two centuries. A set of some hundreds of stations, with about a century of observations of daily precipitation, was identified. An important subset of them was also defined, having long series of observations of temperature, wind, pressure and other quantities. Specific investments were made on important stations sites where observations had been carried for decades, but where the climatological stations did not exist anymore. In the present talk, the Regional Climatological Network of Sardinia will be presented and its consistency discussed. Specific attention will be given to the most important climatological stations which have got more than a century of observations of meteorological quantities. Critical issues of the Regional Climatological Network, like relocation of stations and inhomogeneity of data due to instrumental changes or environmental modifications, will be discussed.

  1. Wind energy as a potential generation source at Ras Benas, Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Ahmed Shata [Physics Department, Faculty of Science in Port Said, Suez Canal University (Egypt)

    2010-10-15

    Analysis of the wind characteristics in Ras Benas city located on the east coast of Red Sea in Egypt using measured data (wind, pressure and temperature) and Weibull function were made. Statistical analysis model to evaluate the wind energy potential was introduced. According to the power calculations done for the site, the annual mean wind density is 315 kW/m{sup 2} at a height of 70 m above ground level. This station has a huge wind energy potential for electricity generation, especially during spring and summer seasons, comparing with some European countries. In addition, the monthly wind turbine efficiency parameter ({eta}{sub monthly}) has been calculated by using a commercial wind turbine 1 MW with 70 m hub height to help designers and users in evaluating the potentialities and choosing the suitable wind turbine for the considered site. The use of wind turbine with capacity greater than 1000 kW at this station was recommended. Ras Benas station was selected to install 30 MW-wind farm consists of 20 commercial wind turbines (Nordex S 77) with hub heights and Rotor diameter were 100 and 77 m, respectively. This site has annual wind speed more than 9.8 m/s at 100 m height and enough area to locate these turbines. The estimated energy production using WASP Program of these wind farm was 130 GWh/year. Furthermore, the production costs was found 1.3EUR cent/kWh, which is a competition price at the wind energy world market. (author)

  2. Evaluating Tilt for Wind Plants

    Energy Technology Data Exchange (ETDEWEB)

    Annoni, Jennifer [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Scholbrock, Andrew K. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Churchfield, Matthew J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fleming, Paul A. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-07-03

    The objective of this work is to demonstrate the feasibility of tilt in a wind plant. Tilt control, much like other wind plant control strategies, has the potential to improve the performance of a wind plant. Tilt control uses the tilt angle of the turbine to direct the wake above or below the downstream turbines. This paper presents a study of tilt in two- and three-turbine arrays. Specifically, the authors show that the power production of a two-turbine array can be increased by tilting turbines in a specific orientation. When adding more turbines, as is shown with the three-turbine array, the overall percentage of power gain increases. This outcome deviates from some of the results seen in typical wind plant control strategies. Finally, we discuss the impact this type of control strategy has on the aerodynamics in a wind plant. This analysis demonstrates that a good understanding of wake characteristics is necessary to improve the plant's performance. A tilt strategy such as the one presented in this paper may have implications for future control/optimization studies including optimization of hub heights in a wind plant and analysis of deep array effects.

  3. Offshore wind turbines and bird activity at Blyth

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    In 1996, a study was implemented to ultimately determine the impact of two 2MW wind turbines situated 900 metres offshore of the north-east of England. The turbines, with a hub height of 66 metres, began operation in December 2000. Earlier, similar studies were carried out on a row of wind turbines mounted on the harbour wall of the nearby town of Blyth. The report gives details of (i) total mortality and mortality due to the turbines; (ii) number of bird strikes; (iii) habitat displacement; (iv) feeding grounds; (v) flight routes and (vi) impact on bird populations of a nearby Site of Special Scientific Interest. The study was conducted by AMEC Wind Limited under contract to the DTI.

  4. Review of Wind Energy Forecasting Methods for Modeling Ramping Events

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S; Lundquist, J K; Marjanovic, N; Williams, J L; Rhodes, M; Chow, T K; Maxwell, R

    2011-03-28

    Tall onshore wind turbines, with hub heights between 80 m and 100 m, can extract large amounts of energy from the atmosphere since they generally encounter higher wind speeds, but they face challenges given the complexity of boundary layer flows. This complexity of the lowest layers of the atmosphere, where wind turbines reside, has made conventional modeling efforts less than ideal. To meet the nation's goal of increasing wind power into the U.S. electrical grid, the accuracy of wind power forecasts must be improved. In this report, the Lawrence Livermore National Laboratory, in collaboration with the University of Colorado at Boulder, University of California at Berkeley, and Colorado School of Mines, evaluates innovative approaches to forecasting sudden changes in wind speed or 'ramping events' at an onshore, multimegawatt wind farm. The forecast simulations are compared to observations of wind speed and direction from tall meteorological towers and a remote-sensing Sound Detection and Ranging (SODAR) instrument. Ramping events, i.e., sudden increases or decreases in wind speed and hence, power generated by a turbine, are especially problematic for wind farm operators. Sudden changes in wind speed or direction can lead to large power generation differences across a wind farm and are very difficult to predict with current forecasting tools. Here, we quantify the ability of three models, mesoscale WRF, WRF-LES, and PF.WRF, which vary in sophistication and required user expertise, to predict three ramping events at a North American wind farm.

  5. A Large Eddy Simulation Study for upstream wind energy conditioning

    Science.gov (United States)

    Sharma, V.; Calaf, M.; Parlange, M. B.

    2013-12-01

    The wind energy industry is increasingly focusing on optimal power extraction strategies based on layout design of wind farms and yaw alignment algorithms. Recent field studies by Mikkelsen et al. (Wind Energy, 2013) have explored the possibility of using wind lidar technology installed at hub height to anticipate incoming wind direction and strength for optimizing yaw alignment. In this work we study the benefits of using remote sensing technology for predicting the incoming flow by using large eddy simulations of a wind farm. The wind turbines are modeled using the classic actuator disk concept with rotation, together with a new algorithm that permits the turbines to adapt to varying flow directions. This allows for simulations of a more realistic atmospheric boundary layer driven by a time-varying geostrophic wind. Various simulations are performed to investigate possible improvement in power generation by utilizing upstream data. Specifically, yaw-correction of the wind-turbine is based on spatio-temporally averaged wind values at selected upstream locations. Velocity and turbulence intensity are also considered at those locations. A base case scenario with the yaw alignment varying according to wind data measured at the wind turbine's hub is also used for comparison. This reproduces the present state of the art where wind vanes and cup anemometers installed behind the rotor blades are used for alignment control.

  6. Assessing the Impacts of Low Level Jets' Negative Wind Shear over Wind Turbines

    Science.gov (United States)

    Gutierrez, Walter; Ruiz-Columbie, Arquimedes; Tutkun, Murat; Castillo, Luciano

    2016-11-01

    Nocturnal Low Level Jets (LLJs) are defined as relative maxima in the vertical profile of the horizontal wind speed at the top of the stable boundary layer. Such peaks constitute major power resources, since they are observed at altitudes within the heights of commercial-size wind turbines. However, a wind speed maximum implies a transition from a positive wind shear below the maximum height to a negative one above. The effect that such transition inflicts on wind turbines has not been thoroughly studied. Here we focused on the impacts that the LLJ negative wind shears have over commercial size wind turbines. Using actual atmospheric LLJ data of high frequency as input for the NREL aeroelastic simulator FAST, different scenarios were created varying the LLJ maximum height with respect to the wind turbine hub height. We found only slight changes in the deflection and load averages for those scenarios, whereas the corresponding variances appear to decrease when a larger portion of the wind turbine sweeping area is affected by the negative shear. The exception was observed in the junction between the tower top and the nacelle, where a deflection maximum was detected that might reveal a critical structural point. The authors gratefully acknowledge the following Grants for this research: NSFCBET #1157246, NSFCMMI #1100948, NSFOISE1243482.

  7. Spatial mapping and attribution of Wyoming wind turbines, 2012

    Science.gov (United States)

    O'Donnell, Michael S.; Fancher, Tammy S.

    2014-01-01

    These data represent locations of wind turbines found within Wyoming as of August 2012. We assigned each wind turbine to a wind farm and, in these data, provide information about each turbine’s potential megawatt output, rotor diameter, hub height, rotor height, the status of the land ownership where the turbine exists, the county each turbine is located in, wind farm power capacity, the number of units currently associated with each wind farm, the wind turbine manufacturer and model, the wind farm developer, the owner of the wind farm, the current purchaser of power from the wind farm, the year the wind farm went online, and the status of its operation. Some of the attributes are estimates based on the information we found via the American Wind Energy Association and other on-line reports. The locations are derived from National Agriculture Imagery Program (2009 and 2012) true color aerial photographs and have a positional accuracy of approximately +/-5 meters. These data will provide a planning tool for wildlife- and habitat-related projects underway at the U.S. Geological Survey’s Fort Collins Science Center and other government and non-government organizations. Specifically, we will use these data to support quantifying disturbances of the landscape as related to wind energy as well as to quantify indirect disturbances to flora and fauna. This data set represents an update to a previous version by O’Donnell and Fancher (2010).

  8. A climatological description of the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, C.H.

    1990-05-22

    This report provides a general climatological description of the Savannah River Site. The description provides both regional and local scale climatology. The regional climatology includes a general regional climatic description and presents information on occurrence frequencies of the severe meteorological phenomena that are important considerations in the design and siting of a facility. These phenomena include tornadoes, thunderstorms, hurricanes, and ice/snow storms. Occurrence probabilities given for extreme tornado and non-tornado winds are based on previous site specific studies. Local climatological conditions that are significant with respect to the impact of facility operations on the environment are described using on-site or near-site meteorological data. Summaries of wind speed, wind direction, and atmospheric stability are primarily based on the most recently generated five-year set of data collected from the onsite meteorological tower network (1982--86). Temperature, humidity, and precipitation summaries include data from SRL's standard meteorological instrument shelter and the Augusta National Weather Service office at Bush Field through 1986. A brief description of the onsite meteorological monitoring program is also provided. 24 refs., 15 figs., 22 tabs.

  9. Atmospheric Stability Impacts on Power Curves of Tall Wind Turbines - An Analysis of a West Coast North American Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S; Lundquist, J K

    2010-02-22

    Tall wind turbines, with hub heights at 80 m or above, can extract large amounts of energy from the atmosphere because they are likely to encounter higher wind speeds, but they face challenges given the complex nature of wind flow and turbulence at these heights in the boundary layer. Depending on whether the boundary layer is stable, neutral, or convective, the mean wind speed, direction, and turbulence properties may vary greatly across the tall turbine swept area (40 to 120 m AGL). This variability can cause tall turbines to produce difference amounts of power during time periods with identical hub height wind speeds. Using meteorological and power generation data from a West Coast North American wind farm over a one-year period, our study synthesizes standard wind park observations, such as wind speed from turbine nacelles and sparse meteorological tower observations, with high-resolution profiles of wind speed and turbulence from a remote sensing platform, to quantify the impact of atmospheric stability on power output. We first compare approaches to defining atmospheric stability. The standard, limited, wind farm operations enable the calculation only of a wind shear exponent ({alpha}) or turbulence intensity (I{sub U}) from cup anemometers, while the presence at this wind farm of a SODAR enables the direct observation of turbulent kinetic energy (TKE) throughout the turbine rotor disk. Additionally, a nearby research meteorological station provided observations of the Obukhov length, L, a direct measure of atmospheric stability. In general, the stability parameters {alpha}, I{sub U}, and TKE are in high agreement with the more physically-robust L, with TKE exhibiting the best agreement with L. Using these metrics, data periods are segregated by stability class to investigate power performance dependencies. Power output at this wind farm is highly correlated with atmospheric stability during the spring and summer months, while atmospheric stability exerts

  10. Advances in tourism climatology

    Energy Technology Data Exchange (ETDEWEB)

    Matzarakis, A.; Freitas, C.R. de; Scott, D. (eds.)

    2004-11-01

    This publication grew out of the Second International Workshop of the International Society of Biometeorology, Commission on Climate Tourism and Recreation (ISB-CCTR) that took place at the Orthodox Academy of Crete in Kolimbari, Greece, 8-11 June 2004. The aim of the meeting was to (a) bring together a selection of researchers and tourism experts to review the current state of knowledge of tourism and recreation climatology and (b) explore possibilities for future research and the role of the ISB-CCTR in this. A total of 40 delegates attended the June 2004 ISB-CCTR Workshop. Their fields of expertise included biometeorology, bioclimatology, thermal comfort and heat balance modelling, tourism marketing and planning, urban and landscape planning, architecture, climate change, emission reduction and climate change impact assessment. Participants came from universities and research institutions in Australia, Austria, Canada, Croatia, France, Germany, Greece, Hungary, Italy, the Netherlands, New Zealand, Portugal, Slovenia, United Kingdom and United States of America. Business conducted at the Workshop was divided between five sessions: assessment of climatic resources; climate change; health; weather, sports and risk forecasts; and behaviour and perception. However, the content of this publication is organised so that it reflects the new perspectives and methods that have evolved since the ISB-CCTR was established. (orig.)

  11. The consideration of atmospheric stability within wind farm AEP calculations

    Science.gov (United States)

    Schmidt, Jonas; Chang, Chi-Yao; Dörenkämper, Martin; Salimi, Milad; Teichmann, Tim; Stoevesandt, Bernhard

    2016-09-01

    The annual energy production of an existing wind farm including thermal stratification is calculated with two different methods and compared to the average of three years of SCADA data. The first method is based on steady state computational fluid dynamics simulations and the assumption of Reynolds-similarity at hub height. The second method is a wake modelling calculation, where a new stratification transformation model was imposed on the Jensen an Ainslie wake models. The inflow states for both approaches were obtained from one year WRF simulation data of the site. Although all models underestimate the mean wind speed and wake effects, the results from the phenomenological wake transformation are compatible with high-fidelity simulation results.

  12. Biomes computed from simulated climatologies

    National Research Council Canada - National Science Library

    Claussen, M; Esch, M

    1992-01-01

    The biome model of Prentice is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max...

  13. Local Climatological Data (LCD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Local Climatological Data (LCD) contains summaries from major airport weather stations that include a daily account of temperature extremes, degree days,...

  14. Observational and Dynamical Wave Climatologies. VOS vs Satellite Data

    Science.gov (United States)

    Grigorieva, Victoria; Badulin, Sergei; Chernyshova, Anna

    2013-04-01

    The understanding physics of wind-driven waves is crucially important for fundamental science and practical applications. This is why experimental efforts are targeted at both getting reliable information on sea state and elaborating effective tools of the sea wave forecasting. The global Visual Wave Observations and satellite data from the GLOBWAVE project of the European Space Agency are analyzed in the context of these two viewpoints. Within the first "observational" aspect we re-analyze conventional climatologies of all basic wave parameters for the last decades [5]. An alternative "dynamical" climatology is introduced as a tool of prediction of dynamical features of sea waves on global scales. The features of wave dynamics are studied in terms of one-parametric dependencies of wave heights on wave periods following the theoretical concept of self-similar wind-driven seas [3, 1, 4] and recently proposed approach to analysis of Voluntary Observing Ship (VOS) data [2]. Traditional "observational" climatologies based on VOS and satellite data collections demonstrate extremely consistent pictures for significant wave heights and dominant periods. On the other hand, collocated satellite and VOS data show significant differences in wave heights, wind speeds and, especially, in wave periods. Uncertainties of visual wave observations can explain these differences only partially. We see the key reason of this inconsistency in the methods of satellite data processing which are based on formal application of data interpolation methods rather than on up-to-date physics of wind-driven waves. The problem is considered within the alternative climatology approach where dynamical criteria of wave height-to-period linkage are used for retrieving wave periods and constructing physically consistent dynamical climatology. The key dynamical parameter - exponent R of one-parametric dependence Hs ~ TR shows dramatically less pronounced latitudinal dependence as compared to observed Hs

  15. Wind Development on Tribal Lands

    Energy Technology Data Exchange (ETDEWEB)

    Ken Haukaas; Dale Osborn; Belvin Pete

    2008-01-18

    Background: The Rosebud Sioux Tribe (RST) is located in south central South Dakota near the Nebraska border. The nearest community of size is Valentine, Nebraska. The RST is a recipient of several Department of Energy grants, written by Distributed Generation Systems, Inc. (Disgen), for the purposes of assessing the feasibility of its wind resource and subsequently to fund the development of the project. Disgen, as the contracting entity to the RST for this project, has completed all the pre-construction activities, with the exception of the power purchase agreement and interconnection agreement, to commence financing and construction of the project. The focus of this financing is to maximize the economic benefits to the RST while achieving commercially reasonable rates of return and fees for the other parties involved. Each of the development activities required and its status is discussed below. Land Resource: The Owl Feather War Bonnet 30 MW Wind Project is located on RST Tribal Trust Land of approximately 680 acres adjacent to the community of St. Francis, South Dakota. The RST Tribal Council has voted on several occasions for the development of this land for wind energy purposes, as has the District of St. Francis. Actual footprint of wind farm will be approx. 50 acres. Wind Resource Assessment: The wind data has been collected from the site since May 1, 2001 and continues to be collected and analyzed. The latest projections indicate a net capacity factor of 42% at a hub height of 80 meters. The data has been collected utilizing an NRG 9300 Data logger System with instrumentation installed at 30, 40 and 65 meters on an existing KINI radio tower. The long-term annual average wind speed at 65-meters above ground level is 18.2 mph (8.1 mps) and 18.7 mph (8.4 mps) at 80-meters agl. The wind resource is excellent and supports project financing.

  16. Evaluating Tilt for Wind Farms: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Annoni, Jennifer; Scholbrock, Andrew; Churchfield, Matthew; Fleming, Paul

    2017-06-29

    The objective of this work is to demonstrate the feasibility of tilt in a wind plant. Tilt control, much like other wind plant control strategies, has the potential to improve the performance of a wind plant. Tilt control uses the tilt angle of the turbine to direct the wake above or below the downstream turbines. This paper presents a study of tilt in two- and threeturbine arrays. Specifically, the authors show that the power production of a two-turbine array can be increased by tilting turbines in a specific orientation. When adding more turbines, as is shown with the three-turbine array, the overall percentage of power gain increases. This outcome deviates from some of the results seen in typical wind plant control strategies. Finally, we discuss the impact this type of control strategy has on the aerodynamics in a wind plant. This analysis demonstrates that a good understanding of wake characteristics is necessary to improve the plant's performance. A tilt strategy such as the one presented in this paper may have implications for future control/optimization studies including optimization of hub heights in a wind plant and analysis of deep array effects.

  17. The HOAPS-II climatology - Release II of the satellite-derived freshwater flux climatology

    Science.gov (United States)

    Fennig, K.; Klepp, C.; Bakan, S.; Schulz, J.; Graßl, H.

    2003-04-01

    HOAPS-II (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) is the improved global climatology of sea surface parameters and surface energy and freshwater fluxes derived from satellite radiances for the time period July 1987 until the recent dates. Data from polar orbiting radiometers, all available Special Sensor Microwave/Imager (SSM/I) radiometers and the Advanced Very High Resolution Radiometer (AVHRR), have been used to get global fields of surface meteorological and oceanographic parameters but also latent heat flux, evaporation, precipitation and net freshwater flux as well as the wind speed, water vapor- and total water content over ice free ocean areas for various averaging periods and grid sizes including scan orientated data in the NetCDF data format. All retrieval methods have been validated with in situ data on a global scale with a focus on precipitation validation. The new release of the data base is freely available to the community. Additionally, applications of the HOAPS-II data base will demonstrate its ability to detect ground validated High Impact Weather over global oceans that the Global Precipitation Climatology Project (GPCP) climatology and the ECMWF model is frequently missing. Nowcasting of model-unpredicted storms is a high potential application of this new data base.

  18. Characterization of wind power resource and its intermittency

    Science.gov (United States)

    Gunturu, U. B.; Schlosser, C. A.

    2011-12-01

    Wind resource in the continental and offshore United States has been calculated and characterized using metrics that describe - apart from abundance - its availability, persistence and intermittency. The Modern Era Retrospective-Analysis for Research and Applications (MERRA) boundary layer flux data has been used to construct wind power density profiles at 50, 80, 100 and 120 m turbine hub heights. The wind power density estimates at 50 m are qualitatively similar to those in the US wind atlas developed by the National Renewable Energy Laboratory (NREL), but quantitatively a class less in some regions, but are within the limits of uncertainty. We also show that for long tailed distributions like those of the wind power density, the mean is an overestimation and median is a more robust metric for summary representation of wind power resource.Generally speaking, the largest and most available wind power density resources are found in off-shore regions of the Atlantic and Pacific coastline, and the largest on-shore resource potential lies in the central United States. However, the intermittency and widespread synchronicity of on-shore wind power density are substantial, and highlights areas where considerable back-up generation technologies will be required. Generation-duration curves are also presented for the independent systems operator (ISO) zones of the U.S. to highlight the regions with the largest capacity factor (MISO, ERCOT, and SWPP) as well as the periods and extent to which all ISOs contain no wind power and the potential benefits of aggregation on wind power intermittency in each region. The impact of raising the wind turbine hub height on metrics of abundance, persistence, variability and intermittency is analyzed. There is a general increase in availability and abundance of wind resource but there is also an increase in intermittency with respect to a 'usable wind power' crossing level in low resource regions. A similar perspective of wind resource for

  19. Wind Power Meteorology

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Mortensen, Niels Gylling; Landberg, Lars

    : wind profiles and shear, turbulence and gust, and extreme winds. The data used in wind power meteorology stem mainly from three sources: onsite wind measurements, the synoptic networks, and the re-analysis projects. Wind climate analysis, wind resource estimation and siting further require a detailed......Wind power meteorology has evolved as an applied science, firmly founded on boundary-layer meteorology, but with strong links to climatology and geography. It concerns itself with three main areas: siting of wind turbines, regional wind resource assessment, and short-term prediction of the wind...... resource. The history, status and perspectives of wind power meteorology are presented, with emphasis on physical considerations and on its practical application. Following a global view of the wind resource, the elements of boundary layer meteorology which are most important for wind energy are reviewed...

  20. CWEX (Crop/Wind-Energy Experiment): Measurements of the interaction between crop agriculture and wind power

    Science.gov (United States)

    Rajewski, Daniel Andrew

    The current expansion of wind farms in the U.S. Midwest promotes an alternative renewable energy portfolio to conventional energy sources derived from fossil fuels. The construction of wind turbines and large wind farms within several millions of cropland acres creates a unique interaction between two unlike energy sources: electric generation by wind and bio-fuel production derived from crop grain and plant tissues. Wind turbines produce power by extracting mean wind speed and converting a portion of the flow to turbulence downstream of each rotor. Turbine-scale turbulence modifies fluxes of momentum, heat, moisture, and other gaseous constituents (e.g. carbon dioxide) between the crop canopy and the atmospheric boundary layer. Conversely, crop surfaces and tillage elements produce drag on the hub-height wind resource, and the release of sensible and latent heat flux from the canopy or soil influences the wind speed profile. The Crop-Wind Energy Experiment (CWEX) measured momentum, energy, and CO2 fluxes at several locations within the leading line of turbines in a large operational wind farm, and overall turbines promote canopy mixing of wind speed, temperature, moisture, and carbon dioxide in both the day and night. Turbine-generated perturbations of these fluxes are dependent on several factors influencing the turbine operation (e.g. wind speed, wind direction, stability, orientation of surrounding turbines within a wind park) and the cropland surface (e.g. crop type and cultivar, planting density, chemical application, and soil composition and drainage qualities). Additional strategies are proposed for optimizing the synergy between crop and wind power.

  1. Potential and site evaluation for a wind energy project on the Grimsel pass; Potential- und Standortabklaerungen fuer ein Windenergieprojekt auf dem Grimselpass

    Energy Technology Data Exchange (ETDEWEB)

    Kapp, Ch.; Schwer, P.; Brenni, R.

    2002-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of an evaluation made concerning the suitability of the Grimsel pass in Switzerland for the installation of wind turbines. The report presents wind and climate measurements made on-site and those extrapolated from data collected at the Grimsel weather station. The accuracy of the data is discussed and long-term extrapolations are made. The analysis of the data, including turbulence analysis, and the methods used to estimate wind conditions at hub height are discussed. The method used to model the wind conditions is described and the results discussed. The report makes recommendations on the requirements that are to be placed on the wind converters with respect to turbulence, wind-gusts and icing-up as well as on the foundations and accessibility of the turbines.

  2. Analysis of Rhode Island Coastal Wind Profiles

    Science.gov (United States)

    Knorr, K. I.; Merrill, J. T.

    2012-12-01

    Eleven wind profile data sets were collected at sites in Rhode Island between 2007 and the present, extending over periods from 6 to 20 months, with a mean of 14 months. The data was gathered from meteorological towers via anemometers and wind vanes at heights up to 60 m, or using SoDAR (Sonic Detection And Ranging) instruments at heights up to 200 m. Wind speeds are generally greater in the fall and winter, with minimum wind speeds occurring in the summer. Winds blow most frequently from the northwest in the winter and from the southwest in the summer. The power law describes wind speed with height in neutral static stability conditions; the fitted shear coefficient characterizes the distribution and is used in wind resource assessment. Marine sites exhibit higher wind speeds and lower shear than terrestrial sites, due to lower surface drag. In contrast, terrestrial sites experience more shear and greater temporal variability. The magnitude of diel and seasonal differences between marine and terrestrial locations will be discussed. The land-breeze sea-breeze cycle influences wind throughout the study area; the magnitude of this variation, along with azimuthal shear will be considered. In addition to the short-term profile data, we used several multi-decadal single height anemometer data sets. Wind estimates at hub height over an extended time period calculated using Measure Correlate Predict (MCP) algorithms will be discussed in the context of hypothesized temporal trends in the wind speeds. Utilization of such data for wind energy and other applications will be discussed.

  3. Lake Michigan Offshore Wind Feasibility Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Boezaart, Arnold [GVSU; Edmonson, James [GVSU; Standridge, Charles [GVSU; Pervez, Nahid [GVSU; Desai, Neel [University of Michigan; Williams, Bruce [University of Delaware; Clark, Aaron [GVSU; Zeitler, David [GVSU; Kendall, Scott [GVSU; Biddanda, Bopi [GVSU; Steinman, Alan [GVSU; Klatt, Brian [Michigan State University; Gehring, J. L. [Michigan State University; Walter, K. [Michigan State University; Nordman, Erik E. [GVSU

    2014-06-30

    The purpose of this project was to conduct the first comprehensive offshore wind assessment over Lake Michigan and to advance the body of knowledge needed to support future commercial wind energy development on the Great Lakes. The project involved evaluation and selection of emerging wind measurement technology and the permitting, installation and operation of the first mid-lake wind assessment meteorological (MET) facilities in Michigan’s Great Lakes. In addition, the project provided the first opportunity to deploy and field test floating LIDAR and Laser Wind Sensor (LWS) technology, and important research related equipment key to the sitting and permitting of future offshore wind energy development in accordance with public participation guidelines established by the Michigan Great Lakes Wind Council (GLOW). The project created opportunities for public dialogue and community education about offshore wind resource management and continued the dialogue to foster Great Lake wind resource utilization consistent with the focus of the GLOW Council. The technology proved to be effective, affordable, mobile, and the methods of data measurement accurate. The public benefited from a substantial increase in knowledge of the wind resources over Lake Michigan and gained insights about the potential environmental impacts of offshore wind turbine placements in the future. The unique first ever hub height wind resource assessment using LWS technology over water and development of related research data along with the permitting, sitting, and deployment of the WindSentinel MET buoy has captured public attention and has helped to increase awareness of the potential of future offshore wind energy development on the Great Lakes. Specifically, this project supported the acquisition and operation of a WindSentinel (WS) MET wind assessment buoy, and associated research for 549 days over multiple years at three locations on Lake Michigan. Four research objectives were defined for the

  4. Global ocean wind power sensitivity to surface layer stability

    Science.gov (United States)

    Capps, Scott B.; Zender, Charles S.

    2009-05-01

    Global ocean wind power has recently been assessed (W. T. Liu et al., 2008) using scatterometry-based 10 m winds. We characterize, for the first time, wind power at 80 m (typical wind turbine hub height) above the global ocean surface, and account for the effects of surface layer stability. Accounting for realistic turbine height and atmospheric stability increases mean global ocean wind power by +58% and -4%, respectively. Our best estimate of mean global ocean wind power is 731 W m-2, about 50% greater than the 487 W m-2 based on previous methods. 80 m wind power is 1.2-1.5 times 10 m power equatorward of 30° latitude, between 1.4 and 1.7 times 10 m power in wintertime storm track regions and >6 times 10 m power in stable regimes east of continents. These results are relatively insensitive to methodology as wind power calculated using a fitted Weibull probability density function is within 10% of power calculated from discrete wind speed measurements over most of the global oceans.

  5. Estimation of fatigue and extreme load distributions from limited data with application to wind energy systems.

    Energy Technology Data Exchange (ETDEWEB)

    Fitzwater, LeRoy M. (Stanford University, Stanford, CA)

    2004-01-01

    An estimate of the distribution of fatigue ranges or extreme loads for wind turbines may be obtained by separating the problem into two uncoupled parts, (1) a turbine specific portion, independent of the site and (2) a site-specific description of environmental variables. We consider contextually appropriate probability models to describe the turbine specific response for extreme loads or fatigue. The site-specific portion is described by a joint probability distribution of a vector of environmental variables, which characterize the wind process at the hub-height of the wind turbine. Several approaches are considered for combining the two portions to obtain an estimate of the extreme load, e.g., 50-year loads or fatigue damage. We assess the efficacy of these models to obtain accurate estimates, including various levels of epistemic uncertainty, of the turbine response.

  6. Application of numerical weather prediction in wind power forecasting: Assessment of the diurnal cycle

    Directory of Open Access Journals (Sweden)

    Tobias Heppelmann

    2017-06-01

    Full Text Available For a secure integration of weather dependent renewable energies in Germany's mixed power supply, precise forecasts of expected wind power are indispensable. These in turn are heavily dependent on numerical weather prediction (NWP. With this relevant area of application, NWP models need to be evaluated concerning new variables such as wind speed at hub heights of wind power plants. This article presents verification results of the deterministic NWP forecasts of the global ICON model, its ICON-EU nest, the COSMO-EU, and the COSMO-DE as well as of the ensemble prediction system COSMO-DE-EPS of the German National Weather Service (DWD, against wind mast observations. The focus is on the diurnal cycle in the Planetary Boundary Layer as wind power forecasts for Germany exhibit pronounced systematic amplitude and phase errors in the morning and evening hours. NWP forecasts with lead times up to 48 hours are examined. All considered NWP models reveal shortcomings concerning the representation of the diurnal cycle. Especially in summertime at onshore locations, when Low-Level Jets form, nocturnal wind speeds at hub height are underestimated. In the COSMO model, stable conditions are not sufficiently reflected in the first part of the night and the vertical mixing after sunrise establishes too late. The verification results of the COSMO-DE-EPS confirm the deficiencies of the deterministic forecasts. The deficiencies are present in all ensemble members and thus indicate potential for improvement not only in the model physics parameterization but also concerning the physical ensemble perturbations.

  7. Collecting of new data on existing wind energy converters

    Science.gov (United States)

    Jensen, S. A.; Bjerregaard, E. T. D.; Paulsen, U. S.

    Measurements on a 55 kW VESTAS wind turbine were carried out during a period of approximately 2 months. The wind turbine is erected at a farm, and the produced energy is used for central heating and in cooling and drying systems at the farm. The energy production of the wind turbine is calculated as a function of the annual mean wind speed, and it is assumed that the wind speed frequency distribution is a Rayleigh distribution. The energy production during a period of 46 days from January the 20th to March the 7th 1983 was 20,665 kWh, and the total energy consumption by the owner in the same period was 12,983 kWh. The mean wind speed at hub height during the same period was 7.6 m/s. Approximately 8975 kWh or 69 per cent of the consumption was delivered directly from the wind turbine, and 11,690 kWh produced by the wind turbine was sold to the power supply company.

  8. Effect of Wind Shear on the Characteristics of a Rotating Blade of a Field Horizontal Axis Wind Turbine

    Science.gov (United States)

    Maeda, Takao; Kawabuchi, Hideyuki

    This paper shows the aerodynamic characteristics at the mid-length of a rotor blade of a 10-m-diameter wind turbine exposed to wind shear. A sonic wind speed meter and six cup-anemometers were installed one diameter upwind of the turbine in order to measure wind profiles. The anemometers at the top, middle and bottom levels were installed at heights of 18.3, 13.3 and 8.3 meters, respectively, which correspond to the heights of the tip of the blade at the blade top position, the hub height, and the tip of the blade at the blade bottom position, respectively. Our measurements suggest that the normal force coefficients in strong wind shear conditions are lower than those in weak wind shear condition. Even if the local angle of attack is almost the same, the normal force coefficient shows differences due to the hysteresis effect. In particular, the influence of shear is large not only when there is strong wind shear in a vertical direction, but also when there is strong wind shear in a horizontal direction. A remarkable difference appears in the pressure distribution under these conditions.

  9. U.S. Local Climatological Data (LCD)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Local Climatological Data (LCD) are summaries of climatological conditions from airport and other prominent weather stations managed by NWS, FAA, and DOD. The...

  10. Advanced Modeling System for Optimization of Wind Farm Layout and Wind Turbine Sizing Using a Multi-Level Extended Pattern Search Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    DuPont, Bryony; Cagan, Jonathan; Moriarty, Patrick

    2016-07-01

    This paper presents a system of modeling advances that can be applied in the computational optimization of wind plants. These modeling advances include accurate cost and power modeling, partial wake interaction, and the effects of varying atmospheric stability. To validate the use of this advanced modeling system, it is employed within an Extended Pattern Search (EPS)-Multi-Agent System (MAS) optimization approach for multiple wind scenarios. The wind farm layout optimization problem involves optimizing the position and size of wind turbines such that the aerodynamic effects of upstream turbines are reduced, which increases the effective wind speed and resultant power at each turbine. The EPS-MAS optimization algorithm employs a profit objective, and an overarching search determines individual turbine positions, with a concurrent EPS-MAS determining the optimal hub height and rotor diameter for each turbine. Two wind cases are considered: (1) constant, unidirectional wind, and (2) three discrete wind speeds and varying wind directions, each of which have a probability of occurrence. Results show the advantages of applying the series of advanced models compared to previous application of an EPS with less advanced models to wind farm layout optimization, and imply best practices for computational optimization of wind farms with improved accuracy.

  11. Spatial mapping and attribution of Wyoming wind turbines

    Science.gov (United States)

    O'Donnell, Michael S.; Fancher, Tammy S.

    2010-01-01

    This Wyoming wind-turbine data set represents locations of wind turbines found within Wyoming as of August 1, 2009. Each wind turbine is assigned to a wind farm. For each turbine, this report contains information about the following: potential megawatt output, rotor diameter, hub height, rotor height, land ownership, county, wind farm power capacity, the number of units currently associated with its wind farm, the wind turbine manufacturer and model, the wind farm developer, the owner of the wind farm, the current purchaser of power from the wind farm, the year the wind farm went online, and the status of its operation. Some attributes are estimates based on information that was obtained through the American Wind Energy Association and miscellaneous online reports. The locations are derived from August 2009 true-color aerial photographs made by the National Agriculture Imagery Program; the photographs have a positional accuracy of approximately ?5 meters. The location of wind turbines under construction during the development of this data set will likely be less accurate than the location of turbines already completed. The original purpose for developing the data presented here was to evaluate the effect of wind energy development on seasonal habitat used by greater sage-grouse. Additionally, these data will provide a planning tool for the Wyoming Landscape Conservation Initiative Science Team and for other wildlife- and habitat-related projects underway at the U.S. Geological Survey's Fort Collins Science Center. Specifically, these data will be used to quantify disturbance of the landscape related to wind energy as well as quantifying indirect disturbances to flora and fauna. This data set was developed for the 2010 project 'Seasonal predictive habitat models for greater sage-grouse in Wyoming.' This project's spatially explicit seasonal distribution models of sage-grouse in Wyoming will provide resource managers with tools for conservation planning. These

  12. Evaluation of global wind power

    Science.gov (United States)

    Archer, Cristina L.; Jacobson, Mark Z.

    2005-06-01

    The goal of this study is to quantify the world's wind power potential for the first time from data. Wind speeds are calculated at 80 m, the hub height of modern, 77-m diameter, 1500 kW turbines. Since relatively few observations are available at 80 m, the Least Square extrapolation technique is utilized and revised here to obtain estimates of wind speeds at 80 m given observed wind speeds at 10 m (widely available) and a network of sounding stations. Tower data from the Kennedy Space Center (Florida) were used to validate the results. Globally, ˜13% of all reporting stations experience annual mean wind speeds ≥ 6.9 m/s at 80 m (i.e., wind power class 3 or greater) and can therefore be considered suitable for low-cost wind power generation. This estimate is believed to be conservative. Of all continents, North America has the largest number of stations in class ≥ 3 (453), and Antarctica has the largest percent (60%). Areas with great potential are found in northern Europe along the North Sea, the southern tip of the South American continent, the island of Tasmania in Australia, the Great Lakes region, and the northeastern and northwestern coasts of North America. The global average 10-m wind speed over the ocean from measurements is 6.64 m/s (class 6); that over land is 3.28 m/s (class 1). The calculated 80-m values are 8.60 m/s (class 6) and 4.54 m/s (class 1) over ocean and land, respectively. Over land, daytime 80-m wind speed averages obtained from soundings (4.96 m/s) are slightly larger than nighttime ones (4.85 m/s); nighttime wind speeds increase, on average, above daytime speeds above 120 m. Assuming that statistics generated from all stations analyzed here are representative of the global distribution of winds, global wind power generated at locations with mean annual wind speeds ≥ 6.9 m/s at 80 m is found to be ˜72 TW (˜54,000 Mtoe) for the year 2000. Even if only ˜20% of this power could be captured, it could satisfy 100% of the world's energy

  13. Accounting for the speed shear in wind turbine power performance measurement

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.

    2010-04-15

    The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise the wind field in front of the turbine. However, with the growing size of the turbine rotors during the last years, the effect of the variations of the wind speed within the swept rotor area, and therefore of the power output, cannot be ignored any longer. Primary effects on the power performance are from the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear condition, therefore on the season and the site. It was then proposed to use an equivalent wind speed accounting for the whole speed profile in front of the turbine. The method was first tested with aerodynamic simulations of a multi-megawatt wind turbine which demonstrated the decrease of the scatter in the power curve. A power curve defined in terms of this equivalent wind speed would be less dependant on the shear than the standard power curve. The equivalent wind speed method was then experimentally validated with lidar measurements. Two equivalent wind speed definitions were considered both resulting in the reduction of the scatter in the power curve. As a lidar wind profiler can measure the wind speed at several heights within the rotor span, the wind speed profile is described with more accuracy than with the power law model. The equivalent wind speed derived from measurements, including at least one measurement above hub height, resulted in a smaller scatter in the power curve than the equivalent wind speed derived from profiles extrapolated from measurements

  14. The potential wind power resource in Australia: a new perspective.

    Directory of Open Access Journals (Sweden)

    Willow Hallgren

    Full Text Available Australia's wind resource is considered to be very good, and the utilization of this renewable energy resource is increasing rapidly: wind power installed capacity increased by 35% from 2006 to 2011 and is predicted to account for over 12% of Australia's electricity generation in 2030. Due to this growth in the utilization of the wind resource and the increasing importance of wind power in Australia's energy mix, this study sets out to analyze and interpret the nature of Australia's wind resources using robust metrics of the abundance, variability and intermittency of wind power density, and analyzes the variation of these characteristics with current and potential wind turbine hub heights. We also assess the extent to which wind intermittency, on hourly or greater timescales, can potentially be mitigated by the aggregation of geographically dispersed wind farms, and in so doing, lessen the severe impact on wind power economic viability of long lulls in wind and power generated. Our results suggest that over much of Australia, areas that have high wind intermittency coincide with large expanses in which the aggregation of turbine output does not mitigate variability. These areas are also geographically remote, some are disconnected from the east coast's electricity grid and large population centers, which are factors that could decrease the potential economic viability of wind farms in these locations. However, on the eastern seaboard, even though the wind resource is weaker, it is less variable, much closer to large population centers, and there exists more potential to mitigate it's intermittency through aggregation. This study forms a necessary precursor to the analysis of the impact of large-scale circulations and oscillations on the wind resource at the mesoscale.

  15. The potential wind power resource in Australia: a new perspective.

    Science.gov (United States)

    Hallgren, Willow; Gunturu, Udaya Bhaskar; Schlosser, Adam

    2014-01-01

    Australia's wind resource is considered to be very good, and the utilization of this renewable energy resource is increasing rapidly: wind power installed capacity increased by 35% from 2006 to 2011 and is predicted to account for over 12% of Australia's electricity generation in 2030. Due to this growth in the utilization of the wind resource and the increasing importance of wind power in Australia's energy mix, this study sets out to analyze and interpret the nature of Australia's wind resources using robust metrics of the abundance, variability and intermittency of wind power density, and analyzes the variation of these characteristics with current and potential wind turbine hub heights. We also assess the extent to which wind intermittency, on hourly or greater timescales, can potentially be mitigated by the aggregation of geographically dispersed wind farms, and in so doing, lessen the severe impact on wind power economic viability of long lulls in wind and power generated. Our results suggest that over much of Australia, areas that have high wind intermittency coincide with large expanses in which the aggregation of turbine output does not mitigate variability. These areas are also geographically remote, some are disconnected from the east coast's electricity grid and large population centers, which are factors that could decrease the potential economic viability of wind farms in these locations. However, on the eastern seaboard, even though the wind resource is weaker, it is less variable, much closer to large population centers, and there exists more potential to mitigate it's intermittency through aggregation. This study forms a necessary precursor to the analysis of the impact of large-scale circulations and oscillations on the wind resource at the mesoscale.

  16. Hanford Site climatological data summary 1995 with historical data

    Energy Technology Data Exchange (ETDEWEB)

    Hoitink, D.J.; Burk, K.W.

    1996-05-01

    This document presents the climatological data measured at the US Department of Energy`s Hanford Site for calendar year 1995. Pacific Northwest National Laboratory operates the Hanford Meteorology Station and the Hanford Meteorological Monitoring Network from which these data were collected. The information contained herein includes updated historical climatologies for temperature, precipitation, normal and extreme values of temperature and precipitation, and other miscellaneous meteorological parameters. Further, the data are adjunct to and update Hoitink and Burk (1994, 1995); however, Appendix B--Wind Climatology (1994) is excluded. 1995 was warmer than normal, averaging 54.7 F, 1.4 F above normal (53.3 F). For the 12-month period, 8 months were warmer than normal, and 4 were cooler than normal. 1995 was the wettest year on record. Precipitation totaled 12.31 in., 197% of normal (6.26 in.); snowfall totaled 7.7 in., compared to the normal of 13.8 in. The average wind speed during 1995 was 7.8 mph, 0.1 mph above normal (7.7 mph). The peak gust during the year was 61 mph from the south-southwest on December 12. There were 27 days with peak gusts {ge} 40 mph, compared to a yearly average of 26.

  17. Improving Wind Predictions in the Marine Atmospheric Boundary Layer through Parameter Estimation in a Single-Column Model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jared A.; Hacker, Joshua P.; Delle Monache, Luca; Kosović, Branko; Clifton, Andrew; Vandenberghe, Francois; Rodrigo, Javier Sanz

    2016-12-14

    A current barrier to greater deployment of offshore wind turbines is the poor quality of numerical weather prediction model wind and turbulence forecasts over open ocean. The bulk of development for atmospheric boundary layer (ABL) parameterization schemes has focused on land, partly due to a scarcity of observations over ocean. The 100-m FINO1 tower in the North Sea is one of the few sources worldwide of atmospheric profile observations from the sea surface to turbine hub height. These observations are crucial to developing a better understanding and modeling of physical processes in the marine ABL. In this study, we use the WRF single column model (SCM), coupled with an ensemble Kalman filter from the Data Assimilation Research Testbed (DART), to create 100-member ensembles at the FINO1 location. The goal of this study is to determine the extent to which model parameter estimation can improve offshore wind forecasts.

  18. Climatologies at high resolution for the Earth land surface areas

    CERN Document Server

    Karger, Dirk Nikolaus; Böhner, Jürgen; Kawohl, Tobias; Kreft, Holger; Soria-Auza, Rodrigo Wilber; Zimmermann, Niklaus; Linder, H Peter; Kessler, Michael

    2016-01-01

    High resolution information of climatic conditions is essential to many application in environmental sciences. Here we present the CHELSA algorithm to downscale temperature and precipitation estimates from the European Centre for Medium-Range Weather Forecast (ECMWF) climatic reanalysis interim (ERA-Interim) to a high resolution of 30 arc sec. The algorithm for temperature is based on a statistical downscaling of atmospheric temperature from the ERA-Interim climatic reanalysis. The precipitation algorithm incorporates orographic predictors such as wind fields, valley exposition, and boundary layer height, and a bias correction using Global Precipitation Climatology Center (GPCC) gridded and Global Historical Climate Network (GHCN) station data. The resulting data consist of a monthly temperature and precipitation climatology for the years 1979-2013. We present a comparison of data derived from the CHELSA algorithm with two other high resolution gridded products with overlapping temporal resolution (Tropical R...

  19. A regional climatology of the Humboldt Current System

    Science.gov (United States)

    Grados Quispe, M.; Chaigneau, A.; Blanco, J.; Vasquez, L.; Dominguez, N.

    2009-12-01

    A 3-dimensional, high-resolution, regional climatology of the Humboldt Current System (HCS) north of 25°S is presented. The methodology is based on a four-dimensional ocean interpolation scheme using locally weighted least square fitting, as developed by Dunn and Ridgway [2001] and Ridgway et al. [2002] in the Australian Seas. The method is applied to all the available historical profiles from the National Oceanographic Data Center [WOD05, Boyer et al., 2006], ARGO buoy profiles [http://www.argo.ucsd.edu] for 2000-2007 and historical in situ long-term information from the Peruvian Marine Research Institute (IMARPE) and Fisheries Development Institute (IFOP) for the period 1960-2008. The regional climatology, which extends from the equator to 25°S and from the coast to 8° offshore with a resolution of 0.1°x0.1°, is thus constructed from more than 70 000 temperature profiles, 38 000 salinity profiles and 43 000 oxygen profiles to form a seasonal climatology of temperature and salinity along Peru and northern Chile. The resulting maps depict interesting small-scales coastal properties such as clear distinct upwelling centers and frontal zones. Geostrophic currents relative to 500 m depth are also computed from the density field, highlighting new circulation features. This study provides a contemporaneous view of the circulation and the water masses characteristics in the Humboldt Current System at seasonal scales. This regional climatology represents coastal boundary features (upwelling cells, frontal regions) better than other climatologies. In view of on-going international research efforts to understand the coastal upwelling and coastal currents in the southern ocean off Peru, the main characteristics of the upwelling cell, currents and coastal winds variability of the Pisco (13°S)-San Juan (15°S) region are presented. This improved gridded product is expected to be used for initializing and validating high resolution regional numerical models.

  20. Butinge Wind Power Plant - Pre-engineering

    Energy Technology Data Exchange (ETDEWEB)

    Mollestad, Knut A.

    1997-03-01

    A preliminary study has been done for a wind farm at Butinge in Lithuania consisting of six 600 kW wind turbines. The location of the wind farm is planned near the border with Latvia and near the coast of the Baltic Sea. The preliminary study has through a relatively detailed technical examination of the project, primarily aimed at gathering basic data for budget estimation and cost calculations. Other relevant aspects of the project are also considered. These include an examination of the basis for the project, an analysis of wind conditions, consideration of the various environmental conditions, discussion about the form of organisation and division of responsibility, as well as an examination of the operational and maintenance framework. Based on wind measurements taken at IFE (Institute for Energy Technology), the annual mean wind is estimated to be 7.3 m/s at 45 m height (equivalent to the hub height for the proposed wind turbines). A production calculation has also been done, which shows that the total energy production of the entire wind farm is expected to 9.47 GWh per year. This is equivalent to a use time of 2630 hours respective to a load factor of 30%. The total cost is estimated at 30.2 mill NOK, and the energy price (including operational costs) delivered from the ''power plant wall'', based on this figure and the production estimate, is calculated at 0,32 NOK/kWh. This is based on a lifetime of 20 years for the facility and a 6.5% required rate of return. In addition, there is outlined a possible financial solution based on various price-scenarios and support arrangements. With an equity capital of 8% and 28% external support, the project meets the current energy price in Lithuania (3,4 US cents/kWh). Without support the sales price of the produced energy is increased by approx. 50%. (author)

  1. Development and economic assessment of a grid connected 20 MW installed capacity wind farm

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Shafiqur; Ahmad, Aftab; Al-Hadhrami, Luai M. [Center for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2011-01-15

    The study presents the design and economic assessment of a wind farm of 20 MW installed capacity, located in the Eastern region of Saudi Arabia. The wind farm is designed using 2 MW size wind machines from Vestas at a hub-height of 60 m using specialized WindFarm software. The land area is considered as flat and away from airports, habitats, hospitals, and communication towers. The energy yield and the wake losses were obtained from the energy yield module of the software for the wind farm. On-site data was collected for a period of 1 year and historical meteorological data was obtained from nearby station were utilized in the design of the proposed wind farm. The proposed wind farm could generate 59,037.7 MW h of electricity annually with plant capacity factor of 33.7%, excluding the wake losses of 3.48%. With prevalent wind turbine and other equipment costs, installation, civil works, balance of plants and operation and maintenance costs, the proposed wind farm could produced the energy at US cents 2.94 per kW h. This study clearly indicates that grid connected wind farms could be developed in and around the measurement site. (author)

  2. Feasibility of Small Wind Turbines in Ontario: Integrating Power Curves with Wind Trends

    Directory of Open Access Journals (Sweden)

    Masaō Ashtine

    2016-12-01

    Full Text Available Micro-scale/small wind turbines, unlike larger utility-scale turbines, produce electricity at a rate of 300 W to 10 kW at their rated wind speed and are typically below 30 m in hub-height. These wind turbines have much more flexibility in their costs, maintenance and siting, owing to their size, and can provided wind energy in areas much less suited for direct supply to the grid system. In the future under climate change, the energy landscape will likely shift from the present centralized electricity generation and delivery system to a more distributed and locally-generated electricity and delivery system. In the new system configuration, the role of relatively small sustainable electricity generators like small wind turbines will likely become more prominent. However, the small wind industry has been substantially slow to progress in Ontario, Canada, and there is much debate over its viability in a growing energy dependent economy. This study seeks to demonstrate the performance of a small wind turbine, and speculate on its potential power output and trend over Ontario historically over the last 33 years using the North American Regional Reanalysis (NARR data. We assessed the efficiency of a Bergey Excel 1 kW wind turbine at the pre-established Kortright Centre for Conservation test site, located north of Toronto. Using a novel approach, the Bergey optimized power curve was incorporated with reanalysis data to establish power output across Ontario at three-hour resolution. Small turbine-based wind power around the Great Lakes and eastern James Bay increased during winter and fall, contributing up to 10% of the annual electricity demand in some regions in Ontario. We purport that increases in power output are driven by long-term reductions in sea and lake ice concentrations affecting atmospheric stability in surrounding regions.

  3. Evaluation of Global Wind Power and Interconnected Wind Farms

    Science.gov (United States)

    Archer, C. L.; Jacobson, M. Z.

    2005-12-01

    The world wind power potential is evaluated in this study. Wind speeds are calculated at 80 m, the hub height of modern, 77-m diameter, 1500 W turbines. Since relatively few observations are available at 80 m, the Least Square extrapolation technique is utilized to obtain estimates of wind speeds at 80 m given observed wind speeds at 10 m (widely available) and a network of sounding stations. Globally, about 13% of all reporting stations experience annual mean wind speeds >= 6.9 m/s at 80 m (i.e., wind power class 3 or greater) and can therefore be considered suitable for low-cost wind power generation. This estimate is believed to be conservative. Of all continents, North America has the largest number of stations in class >= 3 (453). Areas with great potential are found in Northern Europe along the North Sea, the southern tip of the South American continent, the island of Tasmania in Australia, the Great Lakes region, and the northeastern and northwestern coasts of North America. Assuming that statistics generated from all stations analyzed here are representative of the global distribution of winds, global wind power generated at locations with mean annual wind speeds >= 6.9 m/s at 80 m is found to be approximately 72 TW (54,000 Mtoe) for the year 2000. Even if only 20% of this power could be captured, it could satisfy 100% of the world's energy demand for all purposes (6,995-10,177 Mtoe) and over seven times the world electricity needs (1.6-1.8 TW). Several practical barriers need to be overcome to fully realize this potential. Wind intermittency could be perceived as one of them. However, interconnecting wind farms through the transmission grid, also known as distributed wind power, is a simple and effective way of reducing deliverable wind power swings caused by wind intermittency. As more farms are interconnected in an array, wind speed correlation among sites decreases and so does the probability that all sites experience the same wind regime at the same

  4. Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence

    DEFF Research Database (Denmark)

    Emmert, J.T.; Hernandez, G.; Jarvis, M.J.;

    2006-01-01

    Stromfjord (67 degrees N, 51 degrees W), and Thule (77 degrees N, 68 degrees W). We examine the wind patterns as a function of magnetic local time and latitude, solar cycle, day of year, and the dawn-dusk and north-south components of the interplanetary magnetic field (IMF B-y and B-z). In magnetic...... at latitudes as low as that of Millstone Hill ( magnetic latitude 53 degrees N). Quiet time Bz effects are negligible except over the magnetic polar cap station of Thule....

  5. International Satellite Cloud Climatology Project (ISCCP)

    Data.gov (United States)

    National Aeronautics and Space Administration — International Satellite Cloud Climatology Project (ISCCP) focuses on the distribution and variation of cloud radiative properties to improve the understanding of the...

  6. Vertical Axis Wind Turbine Design Load Cases Investigation and Comparison with Horizontal Axis Wind Turbine

    DEFF Research Database (Denmark)

    Galinos, Christos; Larsen, Torben J.; Aagaard Madsen, Helge

    2016-01-01

    The paper studies the applicability of the IEC 61400-1 ed.3, 2005 International Standard of wind turbine minimum design requirements in the case of an onshore Darrieus VAWT and compares the results of basic Design Load Cases (DLCs) with those of a 3-bladed HAWT. The study is based on aeroelastic...... computations using the HAWC2 aero-servo-elastic code A 2-bladed 5 MW VAWT rotor is used based on a modified version of the DeepWind rotor For the HAWT simulations the NREL 3-bladed 5 MW reference wind turbine model is utilized Various DLCs are examined including normal power production, emergency shut down.......3 can be used to a large extent with proper interpretation of the DLCs and choice of parameters such as the hub-height. In addition, the design drivers for the VAWT appear to differ from the ones of the HAWT. Normal operation results in the highest tower bottom and blade root loads for the VAWT...

  7. Russian wind atlas

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, A.N.; Bezroukikh, P.P.; Borisenko, M.M. (Russian Danish Institute of Energy Efficiency (RDIEE), Moscow (RU)); Landberg, L. (Risoe National Lab., Roskilde (DK))

    2000-07-01

    The Atlas provides the assessment of wind energy potential in the near-surface 200 metres of the atmospheric boundary layer. It is based on numerical modeling of wind flows according to hydrodynamic laws and takes into account the effects of roughness, orography and sheltering. The primary information is derived from long-term data series from 332 meteorological stations in Russia. The regional climatologies are calculated in the Atlas for five standard heights (10, 30, 50, 100, 200 m) and four roughness classes of flat and homogeneous terrain. Besides, the Atlas provides the maps of wind energy potential in Russia at 50 metres above ground level, the most important height for wind energy applications. The maps show mean wind speeds and mean wind power densities for any region and any of the five basic types of landscape. The Atlas gives recommendations and examples of wind energy resource assessment and siting of wind turbines. (LN)

  8. The NEWS Water Cycle Climatology

    Science.gov (United States)

    Rodell, Matthew; Beaudoing, Hiroko Kato; L'Ecuyer, Tristan; William, Olson

    2012-01-01

    NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

  9. Comparison of high-latitude thermospheric meridionalwinds II: combined FPI, radar and model Climatologies

    Directory of Open Access Journals (Sweden)

    E. M. Griffin

    2004-03-01

    Full Text Available The climatological behaviour of the thermospheric meridional wind above Kiruna, Sweden (67.4°N, 20.4°E has been investigated for seasonal and solar cycle dependence using six different techniques, comprising both model and experimental sources. Model output from both the empirical Horizontal Wind Model (HWM (Hedin et al., 1988 and the numerical Coupled Thermosphere and Ionosphere Model (CTIM are compared to the measured behaviour at Kiruna, as a single site example. The empirical International Reference Ionosphere (IRI model is used as input to an implementation of servo theory, to provide another climatology combining empirical input with a theoretical framework. The experimental techniques have been introduced in a companion paper in this issue and provide climatologies from direct measurements, using Fabry-Perot Interferometers (FPI, together with 2 separate techniques applied to the European Incoherent Scatter radar (EISCAT database to derive neutral winds. One of these techniques uses the same implementation of servo theory as has been used with the IRI model. Detailed comparisons for each season and solar activity category allow for conclusions to be drawn as to the major influences on the climatological behaviour of the wind at this latitude. Comparison of the incoherent scatter radar (ISR derived neutral winds with FPI, empirical model and numerical model winds is important to our understanding and judgement of the validity of the techniques used to derive thermospheric wind databases. The comparisons also test model performance and indicate possible reasons for differences found between the models. In turn, the conclusions point to possible improvements in their formulation. In particular it is found that the empirical models are over-reliant on mid-latitude data in their formulation, and fail to provide accurate estimates of the winds at high-latitudes.

    Key words. Meteorology and atmospheric dynamics (thermospheric dynamics

  10. The measured field performances of eight different mechanical and air-lift water-pumping wind-turbines

    Energy Technology Data Exchange (ETDEWEB)

    Kentfield, J.A.C. [Univ. of Calgary, Alberta (Canada)

    1996-12-31

    Results are presented of the specific performances of eight, different, water-pumping wind-turbines subjected to impartial tests at the Alberta Renewable Energy Test Site (ARETS), Alberta, Canada. The results presented which were derived from the test data, obtained independently of the equipment manufacturers, are expressed per unit of rotor projected area to eliminate the influence of machine size. Hub-height wind speeds and water flow rates for a common lift of 5.5 m (18 ft) constitute the essential test data. A general finding was that, to a first approximation, there were no major differences in specific performance between four units equipped with conventional reciprocating pumps two of which employed reduction gearing and two of which did not. It was found that a unit equipped with a Moyno pump performed well but three air-lift machines had, as was expected, poorer specific performances than the more conventional equipment. 10 refs., 9 figs.

  11. Identification and Attribution of Global Wind Speed Trends at 100m

    Science.gov (United States)

    McGraw, Zachary; Smith, Ronald; Storelvmo, Trude

    2016-04-01

    Recent studies have found evidence that global climate change significantly alters the strength of large-scale wind patterns. Any enduring trends over large regions are potentially of value to understand due to their implications for the wind energy industry. In this study we identify and evaluate global wind speed trends at the wind turbine hub height (~100m) through the use of CMIP5 models, standard reanalyses (ERA-Interim, NCEP2) and a uniquely high-resolution analysis dataset (Vestas Mesoscale Library). By analyzing how wind speeds change across the globe throughout the period 1900-2100 (with emphasis on the satellite era, 1979-2014), we assess the significance of multi-decadal wind speed trends in the context of natural spatial and temporal variability. Our results show substantial differences in regional trends between different datasets though several regions including the Southern Hemisphere mid-latitudes and the Caribbean show consistently substantial changing wind speeds during the satellite era. Wind speed trends tend to diminish over large time scales and follow spatial patterns that link multi-decadal trends to the evolving behaviors of internal variability modes, especially those of ENSO and the Southern Annular Mode (SAM).

  12. An Error-Reduction Algorithm to Improve Lidar Turbulence Estimates for Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Jennifer F.; Clifton, Andrew

    2016-08-01

    Currently, cup anemometers on meteorological (met) towers are used to measure wind speeds and turbulence intensity to make decisions about wind turbine class and site suitability. However, as modern turbine hub heights increase and wind energy expands to complex and remote sites, it becomes more difficult and costly to install met towers at potential sites. As a result, remote sensing devices (e.g., lidars) are now commonly used by wind farm managers and researchers to estimate the flow field at heights spanned by a turbine. While lidars can accurately estimate mean wind speeds and wind directions, there is still a large amount of uncertainty surrounding the measurement of turbulence with lidars. This uncertainty in lidar turbulence measurements is one of the key roadblocks that must be overcome in order to replace met towers with lidars for wind energy applications. In this talk, a model for reducing errors in lidar turbulence estimates is presented. Techniques for reducing errors from instrument noise, volume averaging, and variance contamination are combined in the model to produce a corrected value of the turbulence intensity (TI), a commonly used parameter in wind energy. In the next step of the model, machine learning techniques are used to further decrease the error in lidar TI estimates.

  13. Location of aerodynamic noise sources from a 200 kW vertical-axis wind turbine

    Science.gov (United States)

    Ottermo, Fredric; Möllerström, Erik; Nordborg, Anders; Hylander, Jonny; Bernhoff, Hans

    2017-07-01

    Noise levels emitted from a 200 kW H-rotor vertical-axis wind turbine have been measured using a microphone array at four different positions, each at a hub-height distance from the tower. The microphone array, comprising 48 microphones in a spiral pattern, allows for directional mapping of the noise sources in the range of 500 Hz to 4 kHz. The produced images indicate that most of the noise is generated in a narrow azimuth-angle range, compatible with the location where increased turbulence is known to be present in the flow, as a result of the previous passage of a blade and its support arms. It is also shown that a semi-empirical model for inflow-turbulence noise seems to produce noise levels of the correct order of magnitude, based on the amount of turbulence that could be expected from power extraction considerations.

  14. Locations and attributes of wind turbines in Colorado, 2009

    Science.gov (United States)

    Carr, Natasha B.; Diffendorfer, Jay E.; Fancher, Tammy S.; Latysh, Natalie E.; Leib, Kenneth J.; Matherne, Anne-Marie; Turner, Christine

    2011-01-01

    The Colorado wind-turbine data series provides geospatial data for all wind turbines established within the State as of August 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, and county. Wind energy facility data for each turbine include: facility name, facility power capacity, number of turbines associated with each facility to date, facility developer, facility ownership, year the facility went online, and development status of wind facility. Turbine locations were derived from August 2009 1-meter true-color aerial photographs produced by the National Agriculture Imagery Program; the photographs have a positional accuracy of about + or - 5 meters. The location of turbines under construction during August 2009 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas currently (2011) in development by the U.S. Geological Survey. The Energy Atlas will synthesize data on existing and potential energy development in Colorado and New Mexico and will include additional natural resource data layers. This information may be used by decisionmakers to evaluate and compare the potential benefits and tradeoffs associated with different energy development strategies or scenarios. Interactive maps, downloadable data layers, comprehensive metadata, and decision-support tools will be included in the Energy Atlas. The format of the Energy Atlas will facilitate the integration of information about energy with key terrestrial and aquatic resources for evaluating resource values and minimizing risks from energy development.

  15. Locations and attributes of wind turbines in New Mexico, 2009

    Science.gov (United States)

    Carr, Natasha B.; Diffendorfer, Jay E.; Fancher, Tammy S.; Latysh, Natalie E.; Leib, Kenneth J.; Matherne, Anne-Marie; Turner, Christine

    2011-01-01

    The New Mexico wind-turbine data series provides geospatial data for all wind turbines established within the State as of August 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, and county. Wind energy facility data for each turbine include: facility name, facility power capacity, number of turbines associated with each facility to date, facility developer, facility ownership, year the facility went online, and development status of wind facility. Turbine locations were derived from 1-meter August 2009 true-color aerial photographs produced by the National Agriculture Imagery Program; the photographs have a positional accuracy of about + or - 5 meters. The location of turbines under construction during August 2009 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas currently (2011) in development by the U.S. Geological Survey. The Energy Atlas will synthesize data on existing and potential energy development in Colorado and New Mexico and will include additional natural resource data layers. This information may be used by decisionmakers to evaluate and compare the potential benefits and tradeoffs associated with different energy development strategies or scenarios. Interactive maps, downloadable data layers, comprehensive metadata, and decision-support tools will be included in the Energy Atlas. The format of the Energy Atlas will facilitate the integration of information about energy with key terrestrial and aquatic resources for evaluating resource values and minimizing risks from energy development.

  16. Performance and cost projections for advanced wind turbines

    Science.gov (United States)

    Hock, Susan M.; Thresher, Robert W.; Cohen, Joseph M.

    1990-08-01

    This paper identifies two possible wind turbine system architectures that represent the next generation of horizontal-axis designs, targeted for the mid-1990's. Estimates of the effects of projected design refinements on energy capture and cost are used to calculate cost-of-energy (COE) estimates. Two basic design philosophies are presented: the first represents a system using power electronics to allow variable speed operation and the second represents an optimized stall-controlled rotor. Both concepts take advantage of recent technological innovations including advanced airfoils; innovative control strategies; drive-train improvements; and site-dependent system optimization strategies, such as tall towers for sites with strong vertical wind shears. Our investigation indicates that these design improvements will increase energy capture about 40 to 50 percent with a corresponding negligible impact on cost, when compared with current state-of-the-art wind systems. These performance improvements result in COE estimates ranging between $0.03 and $0.06/kWh for the mid-1990's for sites with annual average hub-height wind speeds from 8.5 mps to 6.8 mps.

  17. Hanford Site climatological data summary 1999 with historical data

    Energy Technology Data Exchange (ETDEWEB)

    DJ Hoitink; KW Burk; JV Ramsdell

    2000-05-11

    This document presents the climatological data measured at the US Department of Energy's Hanford Site for calendar year 1999. Pacific Northwest National Laboratory operates the Hanford Meteorology Station and the Hanford Meteorological Monitoring Network from which these data were collected. The information contained herein includes updated historical climatologies for temperature, precipitation, normal and extreme values of temperature and precipitation, and other miscellaneous meteorological parameters. Further, the data are adjunct to and update Hoitink et al. (1999), and Hoitink and Burk (1994, 1995, 1996, 1997, 1998); however, Appendix B-Wind Climatology (1994) is excluded. 1999 was warmer than normal at the Hanford Meteorology Station with an average temperature of 54.4 F, 1.1 F above normal (53.3 F). The hottest temperature was 105 F on July 28, while the coldest was 18 F on January 3. The maximum temperature of 64 F on August 30 was the lowest maximum temperature ever recorded in August, while the maximum temperature of 76 F on November 13 was the highest maximum temperature ever recorded in November. For the 12-month period, 6 months were warmer than normal and 6 were cooler than normal. 1999 was the fourth driest year on record. Precipitation totaled 3.75 inches, 60% of normal (6.26 inches); snowfall totaled 0.6 inch, the least calendar year snowfall on record (compared to the normal of 13.8 inches). 1999 was the windiest year on record with an average wind speed of 8.8 mph, 1.1 mph above normal (7.7 mph). There were 48 days with peak gust {ge} 40 mph, compared to a yearly average of 26 mph. The peak gust during the year was 65 mph on February 6. The heating-degree days for 1998--1999 were 4,802 (8% below the 5,231 normal). Cooling-degree days for 1999 were 891 (10% below the 994 normal).

  18. Measurement of unsteady loading and power output variability in a micro wind farm model in a wind tunnel

    Science.gov (United States)

    Bossuyt, Juliaan; Howland, Michael F.; Meneveau, Charles; Meyers, Johan

    2017-01-01

    Unsteady loading and spatiotemporal characteristics of power output are measured in a wind tunnel experiment of a microscale wind farm model with 100 porous disk models. The model wind farm is placed in a scaled turbulent boundary layer, and six different layouts, varied from aligned to staggered, are considered. The measurements are done by making use of a specially designed small-scale porous disk model, instrumented with strain gages. The frequency response of the measurements goes up to the natural frequency of the model, which corresponds to a reduced frequency of 0.6 when normalized by the diameter and the mean hub height velocity. The equivalent range of timescales, scaled to field-scale values, is 15 s and longer. The accuracy and limitations of the acquisition technique are documented and verified with hot-wire measurements. The spatiotemporal measurement capabilities of the experimental setup are used to study the cross-correlation in the power output of various porous disk models of wind turbines. A significant correlation is confirmed between streamwise aligned models, while staggered models show an anti-correlation.

  19. Polar low climatology over the Nordic and Barents seas based on satellite passive microwave data

    OpenAIRE

    Smirnova, Julia E.; Golubkin, Pavel A.; Bobylev, Leonid P.; Zabolotskikh, Elizaveta; Chapron, Bertrand

    2015-01-01

    A new climatology of polar lows over the Nordic and Barents seas for 14 seasons (1995/1996-2008/2009) is presented. For the first time in climatological studies of polar lows an approach based on satellite passive microwave data was adopted for polar low identification. A total of 637 polar lows were found in 14 extended winter seasons by combining total atmospheric water vapor content and sea surface wind speed fields retrieved from Special Sensor Microwave/Imager data. As derived, the polar...

  20. Scenario Analysis for Techno-Economic Model Development of U.S. Offshore Wind Support Structures

    Energy Technology Data Exchange (ETDEWEB)

    Damiani, Rick; Ning, Andrew; Maples, Ben; Smith, Aaron; Dykes, Katherine

    2016-09-22

    Challenging bathymetry and soil conditions of future US offshore wind power plants might promote the use of multimember, fixed-bottom structures (or 'jackets') in place of monopiles. Support structures affect costs associated with the balance of system and operation and maintenance. Understanding the link between these costs and the main environmental design drivers is crucial in the quest for a lower levelized cost of energy, and it is the main rationale for this work. Actual cost and engineering data are still scarce; hence, we evaluated a simplified engineering approach to tie key site and turbine parameters (e.g. water depth, wave height, tower-head mass, hub height and generator rating) to the overall support weight. A jacket-and-tower sizing tool, part of the National Renewable Energy Laboratory's system engineering software suite, was utilized to achieve mass-optimized support structures for 81 different configurations. This tool set provides preliminary sizing of all jacket components. Results showed reasonable agreement with the available industry data, and that the jacket mass is mainly driven by water depth, but hub height and tower-head mass become more influential at greater turbine ratings. A larger sensitivity of the structural mass to wave height and target eigenfrequency was observed for the deepest water conditions (>40 m). Thus, techno-economic analyses using this model should be based on accurate estimates of actual metocean conditions and turbine parameters especially for deep waters. The relationships derived from this study will inform National Renewable Energy Laboratory's offshore balance of system cost model, and they will be used to evaluate the impact of changes in technology on offshore wind lower levelized cost of energy.

  1. The climatology of the Red Sea - part 2: the waves

    KAUST Repository

    Langodan, Sabique

    2017-05-09

    The wave climatology of the Red Sea is described based on a 30-year hindcast generated using WAVEWATCH III configured on a 5-km resolution grid and forced by Red Sea reanalysis surface winds from the advanced Weather Research and Forecasting model. The wave simulations have been validated using buoy and altimeter data. The four main wind systems in the Red Sea characterize the corresponding wave climatology. The dominant ones are the two opposite wave systems with different genesis, propagating along the axis of the basin. The highest waves are generated at the centre of the Red Sea as a consequence of the strong seasonal winds blowing from the Tokar Gap on the African side. There is a general long-term trend toward lowering the values of the significant wave height over the whole basin, with a decreasing rate depending on the genesis of the individual systems.

  2. Mesoscale wind fluctuations over Danish waters

    DEFF Research Database (Denmark)

    Vincent, Claire Louise

    - Horns Rev I in the North Sea, and Nysted in the Baltic Sea. The thesis begins with a climatological analysis of wind uctuations on time scales of 1{10 hours at the two sites. A novel method for calculating conditional climatologies of spectral information is proposed, based on binning and averaging...... the time axis of the Hilbert spectrum. Results reveal clear patterns between wind uctuations and locally observed meteorological conditions. The analysis is expanded by classifying wind uctuations on time scales of 1{3 hours according to synoptic patterns, satellite pictures and wind classes. Results...

  3. A seasonal air transport climatology for Kenya

    Science.gov (United States)

    Gatebe, C. K.; Tyson, P. D.; Annegarn, H.; Piketh, S.; Helas, G.

    1999-06-01

    A climatology of air transport to and from Kenya has been developed using kinematic trajectory modeling. Significant months for trajectory analysis have been determined from a classification of synoptic circulation fields. Five-point back and forward trajectory clusters to and from Kenya reveal that the transport corridors to Kenya are clearly bounded and well defined. Air reaching the country originates mainly from the Saharan region and northwestern Indian Ocean of the Arabian Sea in the Northern Hemisphere and from the Madagascan region of the Indian Ocean in the Southern Hemisphere. Transport from each of these source regions show distinctive annual cycles related to the northeasterly Asian monsoon and the southeasterly trade wind maximum over Kenya in May. The Saharan transport in the lower troposphere is at a maximum when the subtropical high over northern Africa is strongly developed in the boreal winter. Air reaching Kenya between 700 and 500 hPa is mainly from Sahara and northwest Indian Ocean in the months of January and March, which gives way to southwest Indian Ocean flow in May and November. In contrast, air reaching Kenya at 400 hPa is mainly from southwest Indian Ocean in January and March, which is replaced by Saharan transport in May and November. Transport of air from Kenya is invariant, both spatially and temporally, in the tropical easterlies to the Congo Basin and Atlantic Ocean in comparison to the transport to the country. Recirculation of air has also been observed but on a limited and often local scale and not to the extent reported in southern Africa.

  4. Baseline layout and design of a 0.8 GW reference wind farm in the North Sea

    DEFF Research Database (Denmark)

    Bak, Thomas; Graham, Angus; Sapronova, Alla

    2017-01-01

    A model of a reference wind farm is presented. It considers the wind and wave climatologies for a specific site and derives two different wind farm layouts. The layouts are then examined in terms of effective wake turbulence intensity for a given climatology, and a model for the influence on capi...

  5. Measurements on and modelling of offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, S. [ed.

    1996-11-01

    The primary project component was measurement on the Vindeby Offshore Wind Farm. Also included are analyses of fatigue loading on the turbines, sea climate, performance of the wind farm and modelling of flow characteristics inside the wind farm. These individual analyses were made to meet the overall objective, which was to devise an adequate design tool to take into account the increased dynamic loading in wind farms. Measurements have been conducted for several years on the wind farm at Vindeby 2-3 km off the coast of the island of Lolland in the South Baltic Sea. The Vindeby Wind Farm consists of 11 Bonus machines with installed capacities of 450 kW, hub height 38 m and rotor diameter 35 m. The separations of the machines in the rows are 300 m (8.6D), and the distance between the rows is equally 300 m. Two machines, 4W and 5E are instrumented for structural measurements; tower base bending, yaw and tilt and edge and flapwise blade root bending moments are measured and statistics for 1/2 hourly consecutive time periods are stored. The statistics include minimum, maximum, mean, standard deviation and the so-called equivalent load widths. The equivalent load width is popularly speaking the amplitude of a sinusoidal load with frequency equal - in this case - to rotational frequency of the wind turbine rotor that would consume the same fatigue life as the actual load sequence. Modelling of fatigue loading in offshore wind farms and the offshore wind climate was carried out with good results. Also, computational flow modelling was performed. (au) 40 tabs., 130 ills., 114 refs.

  6. Introduction to Global Urban Climatology

    Science.gov (United States)

    Varquez, A. C. G.; Kanda, M.; Kawano, N.; Darmanto, N. S.; Dong, Y.

    2016-12-01

    Urban heat island (UHI) is a widely investigated phenomenon in the field of urban climate characterized by the warming of urban areas relative to its surrounding rural environs. Being able to understand the mechanism behind the UHI formation of a city and distinguish its impact from that of global climate change is indispensable when identifying adaptation and mitigation strategies. However, the lack of UHI studies many cities especially for developing countries makes it difficult to generalize the mechanism for UHI formation. Thus, there is an impending demand for studies that focus on the simultaneous analyses of UHI and its trends throughout the world. Hence, we propose a subfield of urban climatology, called "global urban climatology" (GUC), which mainly focuses on the uniform understanding of urban climates across all cities, globally. By using globally applicable methodologies to quantify and compare urban heat islands of cities with diverse backgrounds, including their geography, climate, socio-demography, and other factors, a universal understanding of the mechanisms underlying the formation of the phenomenon can be established. The implementation of GUC involves the use of globally acquired historical observation networks, gridded meteorological parameters from climate models, global geographic information system datasets; the construction of a distributed urban parameter database; and the development of techniques necessary to model the urban climate. Research under GUC can be categorized into three approaches. The collaborative approach (1st) relies on the collection of data from micro-scale experiments conducted worldwide with the aid or development of professional social networking platforms; the analytical approach (2nd) relies on the use of global weather station datasets and their corresponding objectively analysed global outputs; and the numerical approach (3rd) relies on the global estimation of high-resolution urban-representative parameters as

  7. 2015 Wind Technologies Market Report

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Electricity Markets and Policy Group; Bolinger, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Electricity Markets and Policy Group; Barbose, Galen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Darghouth, Naim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hoen, Ben [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mills, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rand, Joe [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Millstein, Dev [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Porter, Kevin [Exeter Associates, Columbia, MD (United States); Widiss, Rebecca [Exeter Associates, Columbia, MD (United States); Oteri, Frank [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, Suzanne [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tian, Tian [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-03

    Annual wind power capacity additions in the United States surged in 2015 and are projected to continue at a rapid clip in the coming five years. Recent and projected near-term growth is supported by the industry’s primary federal incentive—the production tax credit (PTC)—having been extended for several years (though with a phase-down schedule, described further on pages 68-69), as well as a myriad of state-level policies. Wind additions are also being driven by improvements in the cost and performance of wind power technologies, yielding low power sales prices for utility, corporate, and other purchasers. At the same time, the prospects for growth beyond the current PTC cycle remain uncertain: growth could be blunted by declining federal tax support, expectations for low natural gas prices, and modest electricity demand growth. This annual report—now in its tenth year—provides a detailed overview of developments and trends in the U.S. wind power market, with a particular focus on 2015. The report begins with an overview of key installation-related trends: trends in U.S. wind power capacity growth; how that growth compares to other countries and generation sources; the amount and percentage of wind energy in individual states; the status of offshore wind power development; and the quantity of proposed wind power capacity in various interconnection queues in the United States. Next, the report covers an array of wind power industry trends: developments in turbine manufacturer market share; manufacturing and supply-chain developments; wind turbine and component imports into and exports from the United States; project financing developments; and trends among wind power project owners and power purchasers. The report then turns to a summary of wind turbine technology trends: turbine size, hub height, rotor diameter, specific power, and IEC Class. After that, the report discusses wind power performance, cost, and pricing trends. In so doing, it describes

  8. Tall towers for large wind turbines. Report from Vindforsk project V-342

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Staffan; Lyrner, Tomas; Hassanzadeh, Manouchehr; Stalin, Thomas; Johansson, John

    2010-07-15

    The general rule of thumb has been to furnish a wind turbine with a tower as tall as the turbine diameter, with deviations downwards for high wind speed sites. In this report the statement is questioned, with special emphasis for wind turbines sited in forests. The aim of this project was to propose and calculate candidate types of tall towers for on-shore wind turbines in the 3 - 5 MW range, with special reference to siting in forests with a representative wind shear. During the project this scope has been more precisely defined to study 3 and 5 MW wind turbines with hub heights of 80 - 175 meters featuring the following tower solutions: 1. Steel shell tower designed in a conventional way with flanges and both longitudinal and transverse welds. 2. Steel shell tower with bolted friction joints only. 3. Concrete tower with pretensioned steel tendons. 4. Hybrid tower with a lower concrete part and an upper part built as a conventional steel shell. 5. Lattice tower. 6. Wooden tower. During the execution of the project the design of a total of 42 towers was outlined and calculated. Today the welded steel shell tower dominates the wind turbine market. Larger turbines and higher hub heights result in larger optimal tower base diameters. For the road transportation there are limitations due to bridges and other obstacles. In Sweden the limit for transports with special permits in general maximizes the diameter to 4,5 metres. To some extent it is still technically possible to build towers with a less than optimal diameter, but due to the high mass and the large wall thickness they tend to be uneconomical in comparison with other alternatives above a hub height of roughly 100 metres. In this report welded steel shell towers were outlined for 3 MW turbines up to a hub height of 150 metres whereas the limit for the 5 MW towers was 100 metres. When diameter restrictions tend to make welded towers uneconomical, the next logical choice is steel shell towers with bolted friction

  9. Northwest Atlantic Regional Climatology (NCEI Accession 0155889)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To provide an improved oceanographic foundation and reference for multi-disciplinary studies of the Northwest Atlantic Ocean, NCEI Regional Climatology Team...

  10. Global Daily Climatology Network: Kazakhstan subset

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a compilation of in situ daily meteorological observations for Kazakhstan within the framework of joint efforts to create Global Daily Climatology...

  11. U.S. Annual Climatological Summaries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Annual Climatological Summary contains historical monthly and annual summaries for over 8000 U.S. locations. Observing stations are located in the United States of...

  12. Quality Controlled Local Climatological Data (QCLCD) Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Quality Controlled Local Climatological Data (QCLCD) contains summaries from major airport weather stations that include a daily account of temperature extremes,...

  13. Dissipation of turbulence in the wake of a wind turbine

    Science.gov (United States)

    Lundquist, J. K.; Bariteau, L.

    2013-12-01

    The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behavior of an individual wake as it merges with other wakes and propagates downwind is of great importance in assessing wind farm power production as well as impacts of wind energy deployment on local and regional environments. The rate of turbulence dissipation in the wake quantifies the wake behavior as it propagates. In situ field measurements of turbulence dissipation rate in the wake of wind turbines have not been previously collected although correct modeling of dissipation rate is required for accurate simulations of wake evolution. In Fall 2012, we collected in situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine, using the University of Colorado at Boulder's Tethered Lifting System (TLS). The TLS is a unique state-of-the-art tethersonde, proven in numerous boundary-layer field experiments to be able to measure turbulence kinetic energy dissipation rates. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located upwind of the turbine, from a profiling lidar upwind, and from a scanning lidar measuring both inflow to and wake from the turbine. Measurements collected within the wake indicate that dissipation rates are higher in the turbine wake than in the ambient flow. Profiles of dissipation and turbulence throughout the rotor disk suggest that dissipation peaks near the hub height of the turbine. Suggestions for incorporating this information into wind turbine modeling approaches will be provided.

  14. Preliminary study on the applicability of semi-geodesic winding in the design and manufacturing of composite towers

    Science.gov (United States)

    Kayran, A.; İbrahimoǧlu, C. S.

    2014-12-01

    During last twenty years, wind turbine manufacturers took the path of building larger machines to generate more electricity. However, the bigger the size became, the more material was required to support the loads, leading to great weight increases. Larger turbines and higher hub heights also resulted in larger tower base diameters which are limited considering their logistics. In many countries, the limit for transports with special permits maximizes the diameter to 4.5 metres. Considering this fact, the wind turbine market dominated by welded steel shell towers is looking for new structural solutions for their future turbines. Although, composite materials are not used as the structural material in the towers of today's turbines, the demand for larger wind turbines forces engineers to seek for alternative material systems with high specific strength and stiffness ratios to be used in towers. Inspired by the applicability of filament winding in tower production, in the present article we investigated the effect of semi-geodesic winding on the winding angle, thickness, stiffness coefficients and vibration characteristics of filament wound composite conical shells of revolution which simulate wind turbine towers at the structural level. Present study showed that the preset friction applied during semi-geodesic winding is an important design parameter which can be controlled to obtain gradually increasing thickness from tower top to the base of the tower, and favourably alter the dynamic characteristics of the composite towers.

  15. Lidar-based Research and Innovation at DTU Wind Energy - a Review

    Science.gov (United States)

    Mikkelsen, T.

    2014-06-01

    As wind turbines during the past decade have increased in size so have the challenges met by the atmospheric boundary-layer meteorologists and the wind energy society to measure and characterize the huge-volume wind fields surpassing and driving them. At the DTU Wind Energy test site "Østerild" for huge wind turbines, the hub-height of a recently installed 8 MW Vestas V164 turbine soars 143 meters up above the ground, and its rotor of amazing 164 meters in diameter make the turbine tips flicker 225 meters into the sky. Following the revolution in photonics-based telecommunication at the turn of the Millennium new fibre-based wind lidar technologies emerged and DTU Wind Energy, at that time embedded within Rise National Laboratory, began in collaboration with researchers from wind lidar companies to measure remote sensed wind profiles and turbulence structures within the atmospheric boundary layer with the emerging, at that time new, all-fibre-based 1.55 μ coherent detection wind lidars. Today, ten years later, DTU Wind Energy routinely deploys ground-based vertical profilers instead of met masts for high-precision measurements of mean wind profiles and turbulence profiles. At the departments test site "Høvsøre" DTU Wind Energy also routinely calibrate and accredit wind lidar manufactures wind lidars. Meanwhile however, new methodologies for power curve assessment based on ground-based and nacelle based lidars have also emerged. For improving the turbines power curve assessments and for advancing their control with feed-forward wind measurements experience has also been gained with wind lidars installed on turbine nacelles and integrated into the turbines rotating spinners. A new mobile research infrastructure WindScanner.dk has also emerged at DTU Wind Energy. Wind and turbulence fields are today scanned from sets of three simultaneously in space and time synchronized scanning lidars. One set consists of three fast scanning continuous-wave based wind lidars

  16. Influence of the Coriolis force on the structure and evolution of wind turbine wakes

    Science.gov (United States)

    Abkar, Mahdi; Porté-Agel, Fernando

    2016-10-01

    In this study, large-eddy simulation combined with a turbine model is used to investigate the effect of vertical wind veer associated with the Coriolis force on the structure and evolution of wind turbine wakes. In order to isolate the Coriolis effect on the wake, two cases are considered. In the first case, atmospheric boundary-layer flow is driven by a geostrophic wind, including the effect of Earth's rotation and the Coriolis force. In the second case, the boundary-layer flow is unidirectional and is forced by an imposed pressure gradient. Both cases have the same mean horizontal velocity and turbulence intensity at the hub height. The simulation results show that the Coriolis force significantly affects the aerodynamics of the wake including the mean velocity deficit, turbulence statistics, and wake-meandering characteristics downwind of the turbine. In particular, when the flow is forced by a geostrophic wind, vertical wind veer causes a skewed spatial structure in the wake. Moreover, the presence of lateral wind shear, in addition to the vertical one, enhances the shear production of turbulent kinetic energy and the turbulent momentum flux. This leads to a larger flow entrainment and, thus, a faster wake recovery compared to the case forced by unidirectional pressure gradient. Consistent with this result, wake meandering is also stronger in both lateral and vertical directions in the case of geostrophic forcing compared to the case with pressure-gradient forcing.

  17. Lake Michigan Wind Assessment Analysis, 2012 and 2013

    Directory of Open Access Journals (Sweden)

    Charles R Standridge

    2017-03-01

    Full Text Available A study was conducted to address the wind energy potential over Lake Michigan to support a commercial wind farm.  Lake Michigan is an inland sea in the upper mid-western United States.  A laser wind sensor mounted on a floating platform was located at the mid-lake plateau in 2012 and about 10.5 kilometers from the eastern shoreline near Muskegon Michigan in 2013.  Range gate heights for the laser wind sensor were centered at 75, 90, 105, 125, 150, and 175 meters.  Wind speed and direction were measured once each second and aggregated into 10 minute averages.  The two sample t-test and the paired-t method were used to perform the analysis.  Average wind speed stopped increasing between 105 m and 150 m depending on location.  Thus, the collected data is inconsistent with the idea that average wind speed increases with height. This result implies that measuring wind speed at wind turbine hub height is essential as opposed to using the wind energy power law to project the wind speed from lower heights.  Average speed at the mid-lake plateau is no more that 10% greater than at the location near Muskegon.  Thus, it may be possible to harvest much of the available wind energy at a lower height and closer to the shoreline than previously thought.  At both locations, the predominate wind direction is from the south-southwest.  The ability of the laser wind sensor to measure wind speed appears to be affected by a lack of particulate matter at greater heights.   Keywords: wind assessment, Lake Michigan, LIDAR wind sensor, statistical analysis. Article History: Received June 15th 2016; Received in revised form January 16th 2017; Accepted February 2nd 2017 Available online How to Cite This Article: Standridge, C., Zeitler, D., Clark, A., Spoelma, T., Nordman, E., Boezaart, T.A., Edmonson, J.,  Howe, G., Meadows, G., Cotel, A. and Marsik, F. (2017 Lake Michigan Wind Assessment Analysis, 2012 and 2013. Int. Journal of Renewable Energy Development

  18. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2016-07-21

    We evaluate the sensitivity of simulated turbine-height winds to 26 parameters applied in a planetary boundary layer (PBL) scheme and a surface layer scheme of the Weather Research and Forecasting (WRF) model over an area of complex terrain during the Columbia Basin Wind Energy Study. An efficient sampling algorithm and a generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of modeled turbine-height winds. The results indicate that most of the variability in the ensemble simulations is contributed by parameters related to the dissipation of the turbulence kinetic energy (TKE), Prandtl number, turbulence length scales, surface roughness, and the von Kármán constant. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability. The parameter associated with the TKE dissipation rate is found to be the most important one, and a larger dissipation rate can produce larger hub-height winds. A larger Prandtl number results in weaker nighttime winds. Increasing surface roughness reduces the frequencies of both extremely weak and strong winds, implying a reduction in the variability of the wind speed. All of the above parameters can significantly affect the vertical profiles of wind speed, the altitude of the low-level jet and the magnitude of the wind shear strength. The wind direction is found to be modulated by the same subset of influential parameters. Remainder of abstract is in attachment.

  19. A global satellite-assisted precipitation climatology

    Science.gov (United States)

    Funk, C.; Verdin, A.; Michaelsen, J.; Peterson, P.; Pedreros, D.; Husak, G.

    2015-10-01

    Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti) are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high-resolution (0.05°) global precipitation climatologies that perform reasonably well in data-sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05° monthly precipitation climatology, the Climate

  20. A global satellite assisted precipitation climatology

    Directory of Open Access Journals (Sweden)

    C. Funk

    2015-05-01

    Full Text Available Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high resolution (0.05° global precipitation climatologies that perform reasonably well in data sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05° monthly precipitation climatology

  1. A global satellite assisted precipitation climatology

    Science.gov (United States)

    Funk, Christopher C.; Verdin, Andrew P.; Michaelsen, Joel C.; Pedreros, Diego; Husak, Gregory J.; Peterson, P.

    2015-01-01

    Accurate representations of mean climate conditions, especially in areas of complex terrain, are an important part of environmental monitoring systems. As high-resolution satellite monitoring information accumulates with the passage of time, it can be increasingly useful in efforts to better characterize the earth's mean climatology. Current state-of-the-science products rely on complex and sometimes unreliable relationships between elevation and station-based precipitation records, which can result in poor performance in food and water insecure regions with sparse observation networks. These vulnerable areas (like Ethiopia, Afghanistan, or Haiti) are often the critical regions for humanitarian drought monitoring. Here, we show that long period of record geo-synchronous and polar-orbiting satellite observations provide a unique new resource for producing high resolution (0.05°) global precipitation climatologies that perform reasonably well in data sparse regions. Traditionally, global climatologies have been produced by combining station observations and physiographic predictors like latitude, longitude, elevation, and slope. While such approaches can work well, especially in areas with reasonably dense observation networks, the fundamental relationship between physiographic variables and the target climate variables can often be indirect and spatially complex. Infrared and microwave satellite observations, on the other hand, directly monitor the earth's energy emissions. These emissions often correspond physically with the location and intensity of precipitation. We show that these relationships provide a good basis for building global climatologies. We also introduce a new geospatial modeling approach based on moving window regressions and inverse distance weighting interpolation. This approach combines satellite fields, gridded physiographic indicators, and in situ climate normals. The resulting global 0.05° monthly precipitation climatology, the Climate

  2. The Climatology of Australian Aerosol

    Science.gov (United States)

    Mitchell, Ross M.; Forgan, Bruce W.; Campbell, Susan K.

    2017-04-01

    Airborne particles or aerosols have long been recognised for their major contribution to uncertainty in climate change. In addition, aerosol amounts must be known for accurate atmospheric correction of remotely sensed images, and are required to accurately gauge the available solar resource. However, despite great advances in surface networks and satellite retrievals over recent years, long-term continental-scale aerosol data sets are lacking. Here we present an aerosol assessment over Australia based on combined sun photometer measurements from the Bureau of Meteorology Radiation Network and CSIRO/AeroSpan. The measurements are continental in coverage, comprising 22 stations, and generally decadal in timescale, totalling 207 station-years. Monthly climatologies are given at all stations. Spectral decomposition shows that the time series can be represented as a weighted sum of sinusoids with periods of 12, 6 and 4 months, corresponding to the annual cycle and its second and third harmonics. Their relative amplitudes and phase relationships lead to sawtooth-like waveforms sharply rising to an austral spring peak, with a slower decline often including a secondary peak during the summer. The amplitude and phase of these periodic components show significant regional change across the continent. Fits based on this harmonic analysis are used to separate the periodic and episodic components of the aerosol time series. An exploratory classification of the aerosol types is undertaken based on (a) the relative periodic amplitudes of the Ångström exponent and aerosol optical depth, (b) the relative amplitudes of the 6- and 4-month harmonic components of the aerosol optical depth, and (c) the ratio of episodic to periodic variation in aerosol optical depth. It is shown that Australian aerosol can be broadly grouped into three classes: tropical, arid and temperate. Statistically significant decadal trends are found at 4 of the 22 stations. Despite the apparently small

  3. Assessments of wind-energy potential in selected sites from three geopolitical zones in Nigeria: implications for renewable/sustainable rural electrification.

    Science.gov (United States)

    Okeniyi, Joshua Olusegun; Ohunakin, Olayinka Soledayo; Okeniyi, Elizabeth Toyin

    2015-01-01

    Electricity generation in rural communities is an acute problem militating against socioeconomic well-being of the populace in these communities in developing countries, including Nigeria. In this paper, assessments of wind-energy potential in selected sites from three major geopolitical zones of Nigeria were investigated. For this, daily wind-speed data from Katsina in northern, Warri in southwestern and Calabar in southeastern Nigeria were analysed using the Gumbel and the Weibull probability distributions for assessing wind-energy potential as a renewable/sustainable solution for the country's rural-electrification problems. Results showed that the wind-speed models identified Katsina with higher wind-speed class than both Warri and Calabar that were otherwise identified as low wind-speed sites. However, econometrics of electricity power simulation at different hub heights of low wind-speed turbine systems showed that the cost of electric-power generation in the three study sites was converging to affordable cost per kWh of electric energy from the wind resource at each site. These power simulations identified cost/kWh of electricity generation at Kaduna as €0.0507, at Warri as €0.0774, and at Calabar as €0.0819. These bare positive implications on renewable/sustainable rural electrification in the study sites even as requisite options for promoting utilization of this viable wind-resource energy in the remote communities in the environs of the study sites were suggested.

  4. Wind power electricity: the bigger the turbine, the greener the electricity?

    Science.gov (United States)

    Caduff, Marloes; Huijbregts, Mark A J; Althaus, Hans-Joerg; Koehler, Annette; Hellweg, Stefanie

    2012-05-01

    Wind energy is a fast-growing and promising renewable energy source. The investment costs of wind turbines have decreased over the years, making wind energy economically competitive to conventionally produced electricity. Size scaling in the form of a power law, experience curves and progress rates are used to estimate the cost development of ever-larger turbines. In life cycle assessment, scaling and progress rates are seldom applied to estimate the environmental impacts of wind energy. This study quantifies whether the trend toward larger turbines affects the environmental profile of the generated electricity. Previously published life cycle inventories were combined with an engineering-based scaling approach as well as European wind power statistics. The results showed that the larger the turbine is, the greener the electricity becomes. This effect was caused by pure size effects of the turbine (micro level) as well as learning and experience with the technology over time (macro level). The environmental progress rate was 86%, indicating that for every cumulative production doubling, the global warming potential per kWh was reduced by 14%. The parameters, hub height and rotor diameter were identified as Environmental Key Performance Indicators that can be used to estimate the environmental impacts for a generic turbine. © 2012 American Chemical Society

  5. Relevant Criteria for Testing the Quality of Models for Turbulent Wind Speed Fluctuations

    DEFF Research Database (Denmark)

    Frandsen, Sten Tronæs; Ejsing Jørgensen, Hans; Sørensen, John Dalsgaard

    2008-01-01

    -size wind turbines when seeking wind characteristics that correspond to one blade and the entire rotor, respectively. For heights exceeding 50-60  m, the gust factor increases with wind speed. For heights larger than 60-80  m, present assumptions on the value of the gust factor are significantly......Seeking relevant criteria for testing the quality of turbulence models, the scale of turbulence and the gust factor have been estimated from data and compared with predictions from first-order models of these two quantities. It is found that the mean of the measured length scales is approximately...... 10% smaller than the IEC model for wind turbine hub height levels. The mean is only marginally dependent on trends in time series. It is also found that the coefficient of variation of the measured length scales is about 50%. 3  s and 10  s preaveraging of wind speed data are relevant for megawatt...

  6. Simulation of shear and turbulence impact on wind turbine power performance

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.; Courtney, M.S.; Larsen, T.J.; Paulsen, U.S.

    2010-01-15

    Aerodynamic simulations (HAWC2Aero) were used to investigate the influence of the speed shear, the direction shear and the turbulence intensity on the power output of a multi-megawatt turbine. First simulation cases with laminar flow and power law wind speed profiles were compared to the case of a uniform inflow. Secondly, a similar analysis was done for cases with direction shear. In each case, we derived a standard power curve (function of the wind speed at hub height) and power curves obtained with various definitions of equivalent wind speed in order to reduce the scatter due to shear. Thirdly, the variations of the power output and the power curve were analysed for various turbulence intensities. Furthermore, the equivalent speed method was successfully tested on a power curve resulting from simulations cases combining shear and turbulence. Finally, we roughly simulated the wind speed measurements we may get from a LIDAR mounted on the nacelle of the turbine (measuring upwind) and we investigated different ways of deriving an equivalent wind speed from such measurements. (author)

  7. Evaluation of electricity generation and energy cost of wind energy conversion systems (WECSs) in Central Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Goekcek, Murat [Department of Mechanical Engineering, Faculty of Engineering and Architecture, Nigde University Campus, 51100 Nigde (Turkey); Genc, Mustafa Serdar [Department of Airframe and Powerplant, School of Civil Aviation, Erciyes University, 38039 Kayseri (Turkey)

    2009-12-15

    The negative effects of non-renewable fossil fuels have forced scientists to draw attention to clean energy sources which are both environmentally more suitable and renewable. Although Turkey enjoys fairly high wind energy potential, an investigation and exploitation of this source is still below the desired level. In this study which is a preliminary study on wind energy cost in Central Anatolian-Turkey, the wind energy production using time-series approach and the economic evaluation of various wind energy conversion systems (WECSs) enjoying the 2.5, 5, 10, 20, 30, 50, 100 and 150 kW rated power size using the levelised cost of electricity (LCOE) method for the seven different locations in Central Turkey were estimated. In addition, effects of escalation ratio of operation and maintenance cost and annual mean speed on LCOE are taken into account. The wind speed data for a period between 2000 and 2006 years were taken from Turkish State Meteorological Service (TSMS). According to the result of the calculations, it is shown that the WECS of capacity 150 kW produce the energy output 120,978 kWh per year in the Case-A (Pinarbasi) for hub height 30 m and also the LCOE varies in the range of 0.29-30.0$/kWh for all WECS considered. (author)

  8. Wind energy resources in the Ionian Sea

    Energy Technology Data Exchange (ETDEWEB)

    Karamanis, D. [Department of Environmental and Natural Resources Management, University of Ioannina, 30100 Agrinio (Greece); Tsabaris, C.; Georgopoulos, D. [Institute of Oceanography, Hellenic Center for Marine Research, 190 13 Anavyssos, Attica (Greece); Stamoulis, K. [Center of Archaeometry, University of Ioannina, 45221 Ioannina (Greece)

    2011-02-15

    The wind speed and direction as well as the availability, the duration and the diurnal variation of two offshore sites, Zakinthos and Pylos (BZK and BPY) in the Ionian Sea were assessed. For an analysis period of two years, the mean wind speed at 10 m was determined as 5.7 {+-} 0.1 m s{sup -1} and 5.8 {+-} 0.1 m s{sup -1} for the BZK and BPY sites, respectively. The wind speed variations over the hours of the day were quite small. The monthly variation in the average wind speeds was between 4.3 (May) and 7.5 m s{sup -1} (December) for the BZK site and 4.4 (August) and 7.3 m s{sup -1} (December) for the BPY site. Moreover, QuikSCAT satellite mean values for the grids of the two buoy regions were systematically overestimated in comparison to the buoy data with differences in the range from 8 to 13%. Statistical analysis revealed the high QuikSCAT data uncertainty for wind speeds less than 5 m s{sup -1} as the major factor of the observed mean value differences. The mean wind power densities were calculated with the buoy wind speed measurements and were found more than 250 W m{sup -2} at 10 m, suggesting the suitability of the sites for offshore wind energy applications. Capacity factors of up to 48% for energy production were calculated with the existing offshore turbines technology at a hub height of 100 m. Furthermore, the energy yield for different wind turbines and a service life of 20 years were determined from 6.5 to 8.7 and the energy pay-back periods from 2.8 to 2.1 years, respectively. The maximum avoided greenhouse emissions were 140 kt CO{sub 2}-e for an offshore turbine generator of 5 MW and a period of 20 years. (author)

  9. Modelling the wind climate of Ireland

    DEFF Research Database (Denmark)

    Frank, H.P.; Landberg, L.

    1997-01-01

    The wind climate of Ireland has been calculated using the Karlsruhe Atmospheric Mesoscale Model KAMM. The climatology is represented by 65 frequency classes of geostrophic wind that were selected as equiangular direction sectors and speed intervals with equal frequency in a sector. The results...

  10. Preliminary Comparison of March-May Radiosonde Soundings with March-May Climatological Profiles for Yuma, Arizona

    Science.gov (United States)

    2017-02-01

    speed, a Gaussian distribution is not normally used since wind speed is never less than 0. The distributions frequently used for wind speed are the...around zones 16–20 (SD ‒ SD[Rayleigh] > 5 kn with a maximum of 8.2 kn at zone 18). However, since the climate data file has normal distribution - based...Climatological Profiles for Yuma, Arizona by J Cogan and P Haines Approved for public release; distribution unlimited

  11. Wind Resource Assessment in Complex Terrain with a High-Resolution Numerical Weather Prediction Model

    Science.gov (United States)

    Gruber, Karin; Serafin, Stefano; Grubišić, Vanda; Dorninger, Manfred; Zauner, Rudolf; Fink, Martin

    2014-05-01

    A crucial step in planning new wind farms is the estimation of the amount of wind energy that can be harvested in possible target sites. Wind resource assessment traditionally entails deployment of masts equipped for wind speed measurements at several heights for a reasonably long period of time. Simplified linear models of atmospheric flow are then used for a spatial extrapolation of point measurements to a wide area. While linear models have been successfully applied in the wind resource assessment in plains and offshore, their reliability in complex terrain is generally poor. This represents a major limitation to wind resource assessment in Austria, where high-altitude locations are being considered for new plant sites, given the higher frequency of sustained winds at such sites. The limitations of linear models stem from two key assumptions in their formulation, the neutral stratification and attached boundary-layer flow, both of which often break down in complex terrain. Consequently, an accurate modeling of near-surface flow over mountains requires the adoption of a NWP model with high horizontal and vertical resolution. This study explores the wind potential of a site in Styria in the North-Eastern Alps. The WRF model is used for simulations with a maximum horizontal resolution of 800 m. Three nested computational domains are defined, with the innermost one encompassing a stretch of the relatively broad Enns Valley, flanked by the main crest of the Alps in the south and the Nördliche Kalkalpen of similar height in the north. In addition to the simulation results, we use data from fourteen 10-m wind measurement sites (of which 7 are located within valleys and 5 near mountain tops) and from 2 masts with anemometers at several heights (at hillside locations) in an area of 1600 km2 around the target site. The potential for wind energy production is assessed using the mean wind speed and turbulence intensity at hub height. The capacity factor is also evaluated

  12. The new European wind atlas

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Troen, Ib; Ejsing Jørgensen, Hans;

    2014-01-01

    database. Although the project participants will come from the 27 member states it is envisioned that the project will be opened for global participation through test benches for model development and sharing of data – climatologically as well as experimental. Experiences from national wind atlases...... will be utilized, such as the Indian, the South African, the Finnish, the German, the Canadian atlases and others....... European Wind Atlas” aiming at reducing overall uncertainties in determining wind conditions; standing on three legs: A data bank from a series of intensive measuring campaigns; a thorough examination and redesign of the model chain from global, mesoscale to microscale models and creation of the wind atlas...

  13. Comparative Climatology of Terrestrial Planets

    Science.gov (United States)

    Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

    stimulate further research on this critical subject. The study of climate involves much more than understanding atmospheric processes. This subtlety is particularly appreciated for Earth, where chemical cycles, geology, ocean influences, and biology are considered in most climate models. In Part IV, Surface and Interior, we look at the role that geochemical cycles, volcanism, and interior mantle processes play in the stability and evolution of terrestrial planetary climates. There is one vital commonality between the climates of all the planets of the solar system: Regardless of the different processes that dominate each of the climates of Earth, Mars, Venus, and Titan, they are all ultimately forced by radiation from the same star, albeit at variable distances. In Part V, Solar Influences, we discuss how the Sun's early evolution affected the climates of the terrestrial planets, and how it continues to control the temperatures and compositions of planetary atmospheres. This will be of particular interest as models of exoplanets, and the influences of much different stellar types and distances, are advanced by further observations. Comparisons of atmospheric and climate processes between the planets in our solar system has been a focus of numerous conferences over the past decade, including the Exoclimes conference series. In particular, this book project was closely tied to a conference on Comparative Climatology of Terrestrial Planets that was held in Boulder, Colorado, on June 25-28, 2012. This book benefited from the opportunity for the author teams to interact and obtain feedback from the broader community, but the chapters do not in general tie directly to presentations at the conference. The conference, which was organized by a diverse group of atmospheric and climate scientists led by Mark Bullock and Lori Glaze, sought to build connections between the various communities, focusing on synergies and complementary capabilities. Discussion panels at the end of most

  14. Characterization of the Boundary Layer Wind and Turbulence in the Gulf of Mexico

    Science.gov (United States)

    Pichugina, Y. L.; Banta, R. M.; Choukulkar, A.; Brewer, A.; Hardesty, R. M.; McCarty, B.; Marchbanks, R.

    2014-12-01

    A dataset of ship-borne Doppler lidar measurements taken in the Gulf of Mexico was analyzed to provide insight into marine boundary-layer (BL) features and wind-flow characteristics, as needed for offshore wind energy development. This dataset was obtained as part of the intensive Texas Air Quality Study in summer of 2006 (TexAQS06). During the project, the ship, the R/V Ronald H. Brown, cruised in tracks in the Gulf of Mexico along the Texas coast, in Galveston Bay, and in the Houston Ship Channel obtaining air chemistry and meteorological data, including vertical profile measurements of wind and temperature. The primary observing system used in this paper is NOAA/ESRL's High Resolution Doppler Lidar (HRDL), which features high-precision and high-resolution wind measurements and a motion compensation system to provide accurate wind data despite ship and wave motions. The boundary layer in this warm-water region was found to be weakly unstable typically to a depth of 300 m above the sea surface. HRDL data were analyzed to provide 15-min averaged profiles of wind flow properties (wind speed, direction, and turbulence) from the water surface up to 2.5 km at a vertical resolution of 15 m. The paper will present statistics and distributions of these parameters over a wide range of heights and under various atmospheric conditions. Detailed analysis of the BL features including LLJs, wind and directional ramps, and wind shear through the rotor level heights, along with examples of hub-height and equivalent wind will be presented. The paper will discuss the diurnal fluctuations of all quantities critical to wind energy and their variability along the Texas coast.

  15. China: an emerging offshore wind development hotspot. With a new assessment of China's offshore wind potential

    Energy Technology Data Exchange (ETDEWEB)

    Reinvang, Rasmus; Enslow, Rachel; Beaumont, Hubert

    2010-08-15

    This study provides new and more detailed estimates of the offshore wind energy resources in China, with particular focus on Southern China. The study points out that the offshore wind industry is ramping up in China with at least 11.9GW in the development pipeline per April 2010. The study estimates the offshore wind potential of China (excluding Taiwan) to 11,580TWh/year. The study proves estimates and wind energy resource maps per province. Fujian, Zhejiang and Hainan stand out with the highest offshore wind speeds in China while Guangdong also shows significant potential, with annual wind speed averages of 6.5-10.2m/s and an energy density range of 12-36GWh/km2. Even though current offshore wind development is mainly taking place in Fujian and Jiangsu, this study shows that the potential is likely even greater in other provinces. The study was developed by the Chinese Wind Energy Association (CWEA) and Sun Yat-sen University, and commissioned by WWF as part of a project funded by the Norwegian Agency of development Coopeartion (Norad). Methodology and constraints: The wind resource analysis improves upon previous studies in estimating the wind energy generation potential for offshore wind power in China, with available meteorological data adjusted for influence of typhoons. The study models how much energy offshore wind can produce along China's coast up to 100km from the shore by calculating the energy output of theoretical wind farms by applying the power curve of a 3MW turbine at a 100m hub height. In addition the study further expands by giving special consideration to the deep-sea offshore potential at +50m water depths. The study focuses particularly on the coastline from Shandong down to Hainan. The final results provide good indication of the offshore wind resource in China when comparing one area to the other. The report can therefore be used as a preliminary tool to identifying most interesting provinces and locations for offshore wind

  16. Summertime wind climate in Yerevan: valley wind systems

    Science.gov (United States)

    Gevorgyan, Artur

    2017-03-01

    1992-2014 wind climatology analysis in Yerevan is presented with particular focus given to the summertime thermally induced valley wind systems. Persistence high winds are observed in Yerevan during July-August months when the study region is strongly affected by a heat-driven plain-plateau circulation. The local valley winds arrive in Yerevan in the evening hours, generally, from 1500 to 1800 UTC, leading to rapid enhancement of wind speeds and dramatic changes in wind direction. Valley-winds significantly impact the local climate of Yerevan, which is a densely populated city. These winds moderate evening temperatures after hot and dry weather conditions observed during summertime afternoons. On the other hand, valley winds result in significantly higher nocturnal temperatures and more frequent occurrence of warm nights (tn90p) in Yerevan due to stronger turbulent mixing of boundary layer preventing strong surface cooling and temperature drop in nighttime and morning hours. The applied WRF-ARW limited area model is able to simulate the key features of the observed spatial pattern of surface winds in Armenia associated with significant terrain channeling, wind curls, etc. By contrast, ECMWF EPS global model fails to capture mesoscale and local wind systems over Armenia. However, the results of statistical verification of surface winds in Yerevan showed that substantial biases are present in WRF 18-h wind forecasts, as well as, the temporal variability of observed surface winds is not reproduced adequately in WRF-ARW model.

  17. Gulf of Mexico Regional Climatology (NCEI Accession 0123320)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Gulf of Mexico Regional Climatology is a set of objectively analyzed climatological fields of temperature, salinity, oxygen, phosphate, silicate, and nitrate at...

  18. Dispersion climatology in a coastal zone

    DEFF Research Database (Denmark)

    Larsen, Søren Ejling; Gryning, Sven-Erik

    1986-01-01

    system should be used to describe the dispersion. This dispersion classification scheme is used to organize 3 years of data from two meteorological masts, one placed directly at a shoreline and the other roughly 1 km inland. Differences in the dispersion climatology over land and water are studied...

  19. New dynamic NNORSY ozone profile climatology

    Directory of Open Access Journals (Sweden)

    A. K. Kaifel

    2012-01-01

    Full Text Available Climatological ozone profile data are widely used as a-priori information for total ozone using DOAS type retrievals as well as for ozone profile retrieval using optimal estimation, for data assimilation or evaluation of 3-D chemistry-transport models and a lot of other applications in atmospheric sciences and remote sensing. For most applications it is important that the climatology represents not only long term mean values but also the links between ozone and dynamic input parameters. These dynamic input parameters should be easily accessible from auxiliary datasets or easily measureable, and obviously should have a high correlation with ozone. For ozone profile these parameters are mainly total ozone column and temperature profile data. This was the outcome of a user consultation carried out in the framework of developing a new, dynamic ozone profile climatology.

    The new ozone profile climatology is based on the Neural Network Ozone Retrieval System (NNORSY widely used for ozone profile retrieval from UV and IR satellite sounder data. NNORSY allows implicit modelling of any non-linear correspondence between input parameters (predictors and ozone profile target vector. This paper presents the approach, setup and validation of a new family of ozone profile climatologies with static as well as dynamic input parameters (total ozone and temperature profile. The neural network training relies on ozone profile measurement data of well known quality provided by ground based (ozonesondes and satellite based (SAGE II, HALOE, and POAM-III measurements over the years 1995–2007. In total, four different combinations (modes for input parameters (date, geolocation, total ozone column and temperature profile are available.

    The geophysical validation spans from pole to pole using independent ozonesonde, lidar and satellite data (ACE-FTS, AURA-MLS for individual and time series comparisons as well as for analysing the vertical and meridian

  20. Cascade Analysis of a Floating Wind Turbine Rotor

    Science.gov (United States)

    Eliassen, Lene; Jakobsen, Jasna B.; Knauer, Andreas; Nielsen, Finn Gunnar

    2014-12-01

    Mounting a wind turbine on a floating foundation introduces more complexity to the aerodynamic loading. The floater motion contains a wide range of frequencies. To study some of the basic dynamic load effect on the blades due to these motions, a two-dimensional cascade approach, combined with a potential vortex method, is used. This is an alternative method to study the aeroelastic behavior of wind turbines that is different from the traditional blade element momentum method. The analysis tool demands little computational power relative to a full three dimensional vortex method, and can handle unsteady flows. When using the cascade plane, a "cut" is made at a section of the wind turbine blade. The flow is viewed parallel to the blade axis at this cut. The cascade model is commonly used for analysis of turbo machineries. Due to the simplicity of the code it requires little computational resources, however it has limitations in its validity. It can only handle two-dimensional potential flow, i.e. including neither three-dimensional effects, such as the tip loss effect, nor boundary layers and stall effects are modeled. The computational tool can however be valuable in the overall analysis of floating wind turbines, and evaluation of the rotor control system. A check of the validity of the vortex panel code using an airfoil profile is performed, comparing the variation of the lift force, to the theoretically derived Wagner function. To analyse the floating wind turbine, a floating structure with hub height 90 m is chosen. An axial motion of the rotor is considered.

  1. A novel tropopause-related climatology of ozone profiles

    NARCIS (Netherlands)

    Sofieva, V.F.; Tamminen, J.; Kyrola, E.; Mielonen, T.; Veefkind, J.P.; Hassler, B.; Bodeker, G.E.

    2014-01-01

    A new ozone climatology, based on ozonesonde and satellite measurements, spanning the altitude region between the earth's surface and ~60 km is presented (TpO3 climatology). This climatology is novel in that the ozone profiles are categorized according to calendar month, latitude and local tropopaus

  2. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Science.gov (United States)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2017-01-01

    We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.

  3. Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

    Science.gov (United States)

    Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.

    2016-07-01

    We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.

  4. Measurements of Turbulence Dissipation Rates in the Planetary Boundary Layer from Wind Profiling Radars

    Science.gov (United States)

    McCaffrey, K.; Bianco, L.; Wilczak, J. M.; Johnston, P. E.

    2015-12-01

    When forecasting winds at a wind plant for energy production, the turbulence parameterizations are crucial for understanding wind plant performance. Recent research shows that the turbulence (eddy) dissipation rate in planetary boundary layer (PBL) parameterization schemes introduces significant uncertainty in the Weather Research and Forecasting (WRF) model. Thus, developing the capability to measure dissipation rates in the PBL will allow for identification of weaknesses in, and improvements to the parameterizations. We use data from a 915-MHz wind profiling radar at the Boulder Atmospheric Observatory, collected during the XPIA campaign in spring 2015, to identify the critical parameters for measuring eddy dissipation rates using the spectral width method. Radar set-up parameters (e.g., spectral resolution), post-processing techniques (e.g., filtering for non-atmospheric signals), and spectral averaging, are optimized to capture the most accurate power spectrum for measuring spectral widths for use in the computation of the eddy dissipation rates. These estimates are compared to six heights of turbulence-measuring sonic anemometers from 50 - 300 m on a co-located 300 m tower as verification, showing encouraging results. These methods are then applied to the wind profiling radar data being collected in the Wind Forecasting Improvement Project 2 (WFIP2), a DOE funded campaign that aims to improve the ability to forecast hub-height winds from WRF-based models. This campaign uses of a suite of field observations, including many wind profiling radars, in the Columbia River Gorge, a location with complex terrain where turbulence parameterizations are critical for wind energy prediction.

  5. Distribution of wind power resource over Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Nasir, S.M.; Raza, S.M.; Raja, I.A. (Balochistan Univ., Quetta (Pakistan). Dept. of Physics)

    1992-01-01

    The synthesis and presentation of the wind data are required to establish the wind resource climatology for an area. In this respect, wind contour maps are essential to visualize and quantify the variation of wind speed over the country. Using the average data from 59 locations, iso-wind speed contours are drawn by constructing monthly and yearly maps. The most suitable period for utilizing wind potential is May-August. During this period, the country as a whole exhibits the best wind resource potential, with an average speed of about 3 m/s. (3 m/s average wind speed is very poor for wind power generation). The most promising regions for exploiting wind power throughout the year are the coastline, lower Sind and north-western Balochistan. (author).

  6. Wake Turbulence of Two NREL 5-MW Wind Turbines Immersed in a Neutral Atmospheric Boundary-Layer Flow

    CERN Document Server

    Bashioum, Jessica L; Schmitz, Sven; Duque, Earl P N

    2013-01-01

    The fluid dynamics video considers an array of two NREL 5-MW turbines separated by seven rotor diameters in a neutral atmospheric boundary layer (ABL). The neutral atmospheric boundary-layer flow data were obtained from a precursor ABL simulation using a Large-Eddy Simulation (LES) framework within OpenFOAM. The mean wind speed at hub height is 8m/s, and the surface roughness is 0.2m. The actuator line method (ALM) is used to model the wind turbine blades by means of body forces added to the momentum equation. The fluid dynamics video shows the root and tip vortices emanating from the blades from various viewpoints. The vortices become unstable and break down into large-scale turbulent structures. As the wakes of the wind turbines advect further downstream, smaller-scale turbulence is generated. It is apparent that vortices generated by the blades of the downstream wind turbine break down faster due to increased turbulence levels generated by the wake of the upstream wind turbine.

  7. Wind Conditions for Wind Farm Hanstholm

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Hahmann, Andrea N.; Mann, Jakob;

    The net annual energy production (AEP) of the Hanstholm Wind Farm is 158 GWh per year for the Siemens SWT-3.6-120 turbine and 140 GWh for the Vestas V112-3.0 turbine. These values have an uncertainty (standard deviation) of 6%. This result is mainly based on the data for Risø DTU’s test station...... at Høvsøre where wind speeds are measured at approximately the same height as the turbines at Hanstholm and where the terrain is similar. On top of that meso-scale modeling has been used to extrapolate the climatology from Høvsøre to Hanstholm increasing the AEP by almost 6% compared to just using...... the Høvsøre climatology directly. This method of extrapolation is rather new, but several older investigations indicate that the wind resource at Hanstholm is slightly higher than at Høvsøre. The work is carried out for Grontmij-Carl Bro according to a contract dated January 18th 2011....

  8. Post-disaster climatology for hurricanes and tornadoes in the United States: 2000-2009

    Science.gov (United States)

    Eakins, Benjamin James

    Natural disasters can be very devastating to the public during their impact phase. After a natural disaster impacts a region, the response and recovery phases begin immediately. Weather conditions may interrupt emergency response and recovery in the days following the disaster. This study analyzes the climatology of weather conditions during the response and recovery phases of hurricanes and tornadoes to understand how weather may impact both environment and societal needs. Using specific criteria, 66 tornadoes and 16 hurricane cases were defined. National Weather Service (NWS) recognized weather stations were used to provide temperature, precipitation, snowfall, relative humidity, wind speed, and wind direction data. Regional and temporal groups were defined for tornado cases, but only one group was defined for hurricanes. By applying statistical analysis to weather observations taken in the week following the disasters, a climatology was developed for the response and recovery phase. Tornado and hurricane post-disaster climate closely mimicked their synoptic climatology with cooler and drier weather prevailing in days 2-4 after a disaster until the next weather system arrived about 5 days later. Winter tornadoes trended to occur in the Southeast and were associated with more extreme temperature differences than in other regions and season. The results of this study may help governmental and non-governmental organizations prepare for weather conditions during the post-disaster phase.

  9. The Wind Forecast Improvement Project (WFIP). A Public/Private Partnership for Improving Short Term Wind Energy Forecasts and Quantifying the Benefits of Utility Operations -- the Northern Study Area

    Energy Technology Data Exchange (ETDEWEB)

    Finley, Cathy [WindLogics, St. Paul, MN (United States)

    2014-04-30

    This report contains the results from research aimed at improving short-range (0-6 hour) hub-height wind forecasts in the NOAA weather forecast models through additional data assimilation and model physics improvements for use in wind energy forecasting. Additional meteorological observing platforms including wind profilers, sodars, and surface stations were deployed for this study by NOAA and DOE, and additional meteorological data at or near wind turbine hub height were provided by South Dakota State University and WindLogics/NextEra Energy Resources over a large geographical area in the U.S. Northern Plains for assimilation into NOAA research weather forecast models. The resulting improvements in wind energy forecasts based on the research weather forecast models (with the additional data assimilation and model physics improvements) were examined in many different ways and compared with wind energy forecasts based on the current operational weather forecast models to quantify the forecast improvements important to power grid system operators and wind plant owners/operators participating in energy markets. Two operational weather forecast models (OP_RUC, OP_RAP) and two research weather forecast models (ESRL_RAP, HRRR) were used as the base wind forecasts for generating several different wind power forecasts for the NextEra Energy wind plants in the study area. Power forecasts were generated from the wind forecasts in a variety of ways, from very simple to quite sophisticated, as they might be used by a wide range of both general users and commercial wind energy forecast vendors. The error characteristics of each of these types of forecasts were examined and quantified using bulk error statistics for both the local wind plant and the system aggregate forecasts. The wind power forecast accuracy was also evaluated separately for high-impact wind energy ramp events. The overall bulk error statistics calculated over the first six hours of the forecasts at both the

  10. Dependence of model-simulated response to ozone depletion on stratospheric polar vortex climatology

    Science.gov (United States)

    Lin, Pu; Paynter, David; Polvani, Lorenzo; Correa, Gustavo J. P.; Ming, Yi; Ramaswamy, V.

    2017-06-01

    We contrast the responses to ozone depletion in two climate models: Community Atmospheric Model version 3 (CAM3) and Geophysical Fuild Dynamics Laboratory (GFDL) AM3. Although both models are forced with identical ozone concentration changes, the stratospheric cooling simulated in CAM3 is 30% stronger than in AM3 in annual mean, and twice as strong in December. We find that this difference originates from the dynamical response to ozone depletion, and its strength can be linked to the timing of the climatological springtime polar vortex breakdown. This mechanism is further supported by a variant of the AM3 simulation in which the southern stratospheric zonal wind climatology is nudged to be CAM3-like. Given that the delayed breakdown of the southern polar vortex is a common bias among many climate models, previous model-based assessments of the forced responses to ozone depletion may have been somewhat overestimated.

  11. The bioclimatological leaflet as a means conveying climatological information to tourists and the tourism industry

    Science.gov (United States)

    Zaninović, Ksenija; Matzarakis, Andreas

    2009-07-01

    Climate is an important resource for tourism and must be taken into account in tourism promotions. Here, a climate leaflet containing climatological and bioclimatological information for tourists is presented. The bioclimatological conditions are portrayed using mean values and frequency of thermal sensation based on physiologically equivalent temperature for 10-day intervals covering the whole year, along with air and sea temperature, sunshine duration, amount and number of days with precipitation and wind roses. In addition, the Climate Tourism Information Scheme is included. When combined with climatological and bioclimatological conditions, this scheme is valuable for tourists as it enables them to choose the most suitable time period for holidays, with the choice depending on personal preferences and requirements. The information provided here assists the tourism industry and stakeholders in decision-making. As an example, the bioclimatological leaflet for Hvar, an island off the Croatian Adriatic coast, is presented.

  12. Streamwise Evolution of Statistical Events in a Model Wind-Turbine Array

    Science.gov (United States)

    Viestenz, Kyle; Cal, Raúl Bayoán

    2016-02-01

    Hot-wire anemometry data, obtained from a wind-tunnel experiment containing a 3 × 3 model wind-turbine array, are used to conditionally average the Reynolds stresses. Nine profiles at the centreline behind the array are analyzed to characterize the turbulent velocity statistics of the wake flow. Quadrant analysis yields statistical events occurring in the wake of the wind farm where quadrants 2 and 4 produce ejections and sweeps, respectively. The scaled difference between these two events is expressed via the Δ R0 parameter and is based on the Δ S0 quantity as introduced by M. R. Raupach (J Fluid Mech 108:363-382, 1981). Δ R0 attains a maximum value at hub height and changes sign near the top of the rotor. The ratio of quadrant events of upward momentum flux to those of the downward flux, known as the exuberance, is examined and reveals the effect of root vortices persisting to eight rotor diameters downstream. These events are then associated with the triple correlation term present in the turbulent kinetic energy equation of the fluctuations where it is found that ejections play the dual role of entraining mean kinetic energy while convecting turbulent kinetic energy out of the turbine canopy. The development of these various quantities possesses significance in closure models, and is assessed in light of wake remediation, energy transport and power fluctuations, where it is found that the maximum fluctuation is about 30% of the mean power produced.

  13. An Improved Global Wind Resource Estimate for Integrated Assessment Models: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Eurek, Kelly [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sullivan, Patrick [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gleason, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hettinger, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heimiller, Donna [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lopez, Anthony [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-02-01

    This paper summarizes initial steps to improving the robustness and accuracy of global renewable resource and techno-economic assessments for use in integrated assessment models. We outline a method to construct country-level wind resource supply curves, delineated by resource quality and other parameters. Using mesoscale reanalysis data, we generate estimates for wind quality, both terrestrial and offshore, across the globe. Because not all land or water area is suitable for development, appropriate database layers provide exclusions to reduce the total resource to its technical potential. We expand upon estimates from related studies by: using a globally consistent data source of uniquely detailed wind speed characterizations; assuming a non-constant coefficient of performance for adjusting power curves for altitude; categorizing the distance from resource sites to the electric power grid; and characterizing offshore exclusions on the basis of sea ice concentrations. The product, then, is technical potential by country, classified by resource quality as determined by net capacity factor. Additional classifications dimensions are available, including distance to transmission networks for terrestrial wind and distance to shore and water depth for offshore. We estimate the total global wind generation potential of 560 PWh for terrestrial wind with 90% of resource classified as low-to-mid quality, and 315 PWh for offshore wind with 67% classified as mid-to-high quality. These estimates are based on 3.5 MW composite wind turbines with 90 m hub heights, 0.95 availability, 90% array efficiency, and 5 MW/km2 deployment density in non-excluded areas. We compare the underlying technical assumption and results with other global assessments.

  14. Estimating return periods of extreme values from relatively short time series of winds

    Science.gov (United States)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  15. ENSO Ocean Energetics and Observational Wind Power

    Science.gov (United States)

    Kodama, K.; Burls, N.

    2016-12-01

    The viability of wind power as a potential predictor for ENSO state has previously only been investigated in models. Here we use satellite data to obtain observational equatorial wind power which is then decomposed into climatological (ucτc), mixed-mean-perturbation (ucτ' and u'τc), and perturbation (u'τ') components to compare with the wind power/SST relationship seen in the models. The observational wind power components are also used to compare predictive skill with that of their dynamical counterparts-heat content and wind stress-which are more widely accepted and studied as ENSO predictors. The wind power decomposition reveals the u'τ' perturbation component primarily acts as a damping term. We find that the most robust relationship between wind power and SST arises from the u'τc component computed from the perturbation surface currents and climatological wind stress. u'τc is significantly correlated with the Nino 3.4 index and leads by as many as six months, capturing the role of ocean memory. The wind power decomposition highlights exactly how surface currents can weight the contribution of the winds to have more or less of an effect on the ocean state depending on the whether currents and wind stress act together or oppose each other, illustrating that not all wind anomalies are created equal.

  16. Using Large-Eddy Simulations to Define Spectral and Coherence Characteristics of the Hurricane Boundary Layer for Wind-Energy Applications

    Science.gov (United States)

    Worsnop, Rochelle P.; Bryan, George H.; Lundquist, Julie K.; Zhang, Jun A.

    2017-06-01

    Offshore wind-energy development is planned for regions where hurricanes commonly occur, such as the USA Atlantic Coast. Even the most robust wind-turbine design (IEC Class I) may be unable to withstand a Category-2 hurricane (hub-height wind speeds >50 m s^{-1} ). Characteristics of the hurricane boundary layer that affect the structural integrity of turbines, especially in major hurricanes, are poorly understood, primarily due to a lack of adequate observations that span typical turbine heights (hurricane at high spatial (10 m) and temporal (0.1 s) resolution. By comparison with unique flight-level observations from a field project, we find that a relatively simple configuration of the Cloud Model I model accurately represents the properties of Hurricane Isabel (2003) in terms of mean wind speeds, wind-speed variances, and power spectra. Comparisons of power spectra and coherence curves derived from our hurricane simulations to those used in current turbine design standards suggest that adjustments to these standards may be needed to capture characteristics of turbulence seen within the simulated hurricane boundary layer. To enable improved design standards for wind turbines to withstand hurricanes, we suggest modifications to account for shifts in peak power to higher frequencies and greater spectral coherence at large separations.

  17. Coastal zone wind energy. Part I. Synoptic and mesoscale controls and distributions of coastal wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Garstang, M.; Nnaji, S.; Pielke, R.A.; Gusdorf, J.; Lindsey, C.; Snow, J.W.

    1980-03-01

    This report describes a method of determining coastal wind energy resources. Climatological data and a mesoscale numerical model are used to delineate the available wind energy along the Atlantic and Gulf coasts of the United States. It is found that the spatial distribution of this energy is dependent on the locations of the observing sites in relation to the major synoptic weather features as well as the particular orientation of the coastline with respect to the large-scale wind.

  18. Harvesting wind energy from the sea breeze in peri-urban coastal areas by means of small scale wind turbines - Case study: Viladecans, Llobregat Delta, northeast of Iberian Peninsula

    Science.gov (United States)

    Rojas, Jose I.; Cabrera, Barbara; Mazon, Jordi

    2016-04-01

    Wind speed data recorded during 18 years (1993-2010) in the Llobregat Delta (15 km south of Barcelona city; northeast of the Iberian Peninsula) were used to assess the wind energy generated by off-grid small scale wind turbines (the IT-PE-100 and the HP-600W) for the whole year and for the sea breeze period. The computations were made using QBlade, FAST and AeroDyn simulation tools and manufacturer power curves. Using manufacturer data, the HP-600W with hub-height 8 m would deliver 157 kWh during the whole year (78 kWh during the sea breeze period), with an average power of 18 W (37 W). In this work, the results of the simulations are compared with power and energy production data measured in an HP-600W turbine installed in situ from December 2014 to April 2016. Also, the measured power is compared to the power obtained by applying the measured wind in the period 2014-2016 to the manufacturer power curve and the power curve obtained with the simulations. The results of the computations agree with the experimental data, thus validating the proposed approach for wind resource estimation. The feasibility of using a vertical axis wind turbine for obtaining wind energy from the local, thermal wind regimes is also studied. This research confirms that the sea-breeze is an interesting wind energy resource for micro-generation in peri-urban coastal areas where large-scale wind farms cannot be implemented.

  19. Evaluation of Sub-Kilometer Simulations Using Towers for Wind Energy Assessment

    Science.gov (United States)

    Koracin, D.; Vellore, R.; Belu, R.

    2008-12-01

    It is generally known that to accurately resolve atmospheric processes and winds in topographically developed terrain, regional/mesoscale model resolution should be on the order of a kilometer or so. Since these models are still common tools for producing wind density potential maps, it is important to investigate their capabilities and accuracy compared to measurements. Operation of tall towers in western Nevada offered excellent reference information for verification of the Mesoscale Model 5 (MM5) and Weather and Research Forecasting (WRF) simulations in complex terrain. A principal question is whether a nominal increase in the horizontal resolution uniquely produces more accurate wind and turbulence predictions. In this study, we examined the effect of horizontal resolution on the accuracy of regional/mesoscale model predictions for the near surface (standard) height as well as hub heights using tower data in the first 80 m AGL. The models were set up with nine domains, with the first four having horizontal resolutions of 27, 9, 3, and 1 km, respectively. Within the fourth domain there were five sub-domains, all with 333 m resolution. Three of the sub-domains were centered on a 50m tower at each of the four locations, one of sub-domains is centered on an 80m tower, and one on a surface station equipped with a sonic anemometer. The 50m towers were equipped with wind speed measurements at every 10 m and wind direction measurements at 10 and 50 m. The 80m tower had wind speed and direction measurements at 40, 60, and 80m using standard cup and vane as well as 3D sonic anemometers at each level. These measurements provided an excellent set for evaluation of the predicted wind and turbulence aloft with respect to extremes, diurnal variation, and gustiness as well as the success of the various models' physical parameterizations.

  20. Consequences of variations in spatial turbulence characteristics for fatigue life time of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.C.

    1998-09-01

    The fatigue loading of turbines situated in complex terrain is investigated in order to determine the crucial parameters in the spatial structure of the turbulence in such situations. The parameter study is performed by means of numerical calculations, and it embraces three different wind turbine types, representing a pitch controlled concept, a stall controlled concept, and a stall controlled concept with an extremely flexible tower. For each of the turbine concepts, the fatigue load sensibility to the selected turbulence characteristics are investigated for three different mean wind speeds at hub height. The selected mean wind speeds represent the linear-, the stall-, and the post stall aerodynamic region for the stall controlled turbines and analogously the unregulated-, the partly regulated-, and the fully regulated regime for the pitch controlled turbine. Denoting the turbulence component in the mean wind direction by u, the lateral turbulence component by v, and the vertical turbulence component by w, the selected turbulence characteristics comprise the u-turbulence length scale, the ratio between the v- and w-turbulence intensities and the u-turbulence intensity, the uu-coherence decay factor, and finally the u-v and u-w cross-correlations. The turbulence length scale in the mean wind direction gives rise to significant modification of the fatigue loading on all the investigated wind turbine concepts, but for the other selected parameter variations, large individual differences exists between the turbines. With respect to sensitivity to the performed parameter variations, the Vestas V39 wind turbine is the most robust of the investigated turbines. The Nordtank 500/37 turbine, equipped with the (artificial) soft tower, is by far the most sensitive of the investigated turbine concepts - also much more sensitive than the conventional Nordtank 500/37 turbine equipped with a traditional tower. (au) 2 tabs., 43 ills., 7 refs.

  1. Complex terrain wind resource estimation with the wind-atlas method: Prediction errors using linearized and nonlinear CFD micro-scale models

    DEFF Research Database (Denmark)

    Troen, Ib; Bechmann, Andreas; Kelly, Mark C.

    2014-01-01

    Using the Wind Atlas methodology to predict the average wind speed at one location from measured climatological wind frequency distributions at another nearby location we analyse the relative prediction errors using a linearized flow model (IBZ) and a more physically correct fully non-linear 3D...

  2. In Search of the Wind Energy Potential

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik

    2017-01-01

    The worldwide advancement of wind energy is putting high demands on a number of underlying technologies such as wind turbine aerodynamics, structural dynamics, gearbox design, electrical grid connections, and so on. As wind is the only fuel for wind power plants, naturally, wind-meteorology and w......The worldwide advancement of wind energy is putting high demands on a number of underlying technologies such as wind turbine aerodynamics, structural dynamics, gearbox design, electrical grid connections, and so on. As wind is the only fuel for wind power plants, naturally, wind......-meteorology and wind-climatology are essential for any utilization of wind energy. This is what we are concerned about here with a view on what has happened in wind energy potential assessments in the last 25 years where the utilization of wind turbines in national power supply has accelerated and what......., The New Worldwide Microscale Wind Resource Assessment Data on IRENA's Global Atlas (The EUDP Global Wind Atlas, 2015)], and finally, the perspective for the current work with the New European Wind Atlas [E. L. Petersen et al., Energy Bull. 17, 34–39 (2014); Environ. Res. Lett. 8(1), 011005 (2013...

  3. Variability of the vertical profile of wind speed: characterization at various time scales and analytical approximation

    Science.gov (United States)

    Jourdier, Bénédicte; Plougonven, Riwal; Drobinski, Philippe; Dupont, Jean-Charles

    2014-05-01

    Wind measurements are key for the wind resource assessment. But as wind turbines get higher, wind measurement masts are often lower than the future wind turbine hub height. Therefore one of the first steps in the energy yield assessment is the vertical extrapolation of wind measurements. Such extrapolation is often done by approximating the vertical profile of wind speed with an analytical expression: either a logarithmic law which has a theoretical basis in Monin-Obukhov similarity theory; or a power law which is empirical. The present study analyzes the variability of the wind profile and how this variability affects the results of the vertical extrapolation methods. The study is conducted with data from the SIRTA observatory, 20km south of Paris (France). A large set of instrumentation is available, including sonic anemometers at 10 and 30 meters, a LIDAR measuring wind speeds from 40 to 200 meters and a SODAR measuring wind speeds starting from 100m up to 1km. The comparison between the instruments enables to characterize the measurements uncertainties. The observations show that close to the ground the wind is stronger during daytime and weaker at night while higher, around 150 m, the wind is weaker during daytime and stronger at night. Indeed the wind shear has a pronounced diurnal cycle. The vertical extrapolation methods currently used in the industry do not usually take into account the strong variability of the wind profile. The often fit the parameters of the extrapolation law, not on each time step, but on time-averaged profiles. The averaging period may be the whole measurement period or some part of it: there may be one constant parameter computed on the wind profile that was averaged on the whole year of measures, or the year of measures may be divided into a small number of cases (for example into night or daytime data, or into 4 seasons) and the parameter is adjusted for each case. The study analyzes thoroughly the errors generated by both

  4. Synoptic and climatological aspects of extra-tropical cyclones

    Science.gov (United States)

    Leckebusch, G. C.

    2010-09-01

    Mid-latitude cyclones are highly complex dynamical features embedded in the general atmospheric circulation of the extra-tropics. Although the basic mechanisms leading to the formation of cyclones are commonly understood, the specific conditions and physical reasons triggering extreme, partly explosive development, are still under investigation. This includes also the identification of processes which might modulate the frequency and intensity of cyclone systems on time scales from days to centennials. This overview presentation will thus focus on three main topics: Firstly, the dynamic-synoptic structures of cyclones, the possibility to objectively identify cyclones and wind storms, and actual statistical properties of cyclone occurrence under recent climate conditions are addressed. In a second part, aspects of the interannual variability and its causing mechanisms are related to the seasonal predictability of extreme cyclones producing severe storm events. Extending the time frame will mean to deduce information on decadal or even centennial time periods. Thus, actual work to decadal as well as climatological variability and changes will be presented. In the last part of the talk focus will be laid on potential socio-economical impacts of changed cyclone occurrence. By means of global and regional climate modeling, future damages in terms of insured losses will be investigated and measures of uncertainty estimated from a multi-model ensemble analysis will be presented.

  5. A model of the tropical Pacific sea surface temperature climatology

    Science.gov (United States)

    Seager, Richard; Zebiak, Stephen E.; Cane, Mark A.

    1988-01-01

    A model for the climatological mean sea surface temperature (SST) of the tropical Pacific Ocean is developed. The upper ocean response is computed using a time dependent, linear, reduced gravity model, with the addition of a constant depth frictional surface layer. The full three-dimensional temperature equation and a surface heat flux parameterization that requires specification of only wind speed and total cloud cover are used to evaluate the SST. Specification of atmospheric parameters, such as air temperature and humidity, over which the ocean has direct influence, is avoided. The model simulates the major features of the observed tropical Pacific SST. The seasonal evolution of these features is generally captured by the model. Analysis of the results demonstrates the control the ocean has over the surface heat flux from ocean to atmosphere and the crucial role that dynamics play in determining the mean SST in the equatorial Pacific. The sensitivity of the model to perturbations in the surface heat flux, cloud cover specification, diffusivity, and mixed layer depth is discussed.

  6. A climatology of visible surface reflectance spectra

    Science.gov (United States)

    Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas

    2016-09-01

    We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290-740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment-2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes.

  7. Influence of Coriolis forces on the structure and evolution of wind-turbine wakes

    Science.gov (United States)

    Abkar, Mahdi; Porté-Agel, Fernando

    2015-11-01

    In this study, large-eddy simulation (LES) is combined with a turbine model to investigate the effect of Coriolis forces on the structure and evolution of wind-turbine wakes. In order to isolate the Coriolis effect on the turbulent wake flow, two set of simulations are performed. In the first set of simulations, atmospheric boundary layer (ABL) flow is driven by the geostrophic forces including the effect of Earth's rotation, while in the second case, the ABL flow is driven by a unidirectional pressure gradient forcing. Both cases have the same mean horizontal velocity and turbulence intensity at the hub height. The simulation results show that the Coriolis forces significantly affect the spatial distribution of the mean velocity deficit and turbulence statistics in the wake region. In particular, it is found that the Coriolis effect, responsible for vertical wind veer, has important lateral wake stretching effects, which in turn significantly impacts the wake recovery and wake meandering characteristics downwind of the turbines. We also apply the proper orthogonal decomposition (POD) to LES data of the wake. The results indicate a very high correlation between the most energetic modes and both maximum velocity deficit and wake meandering characteristics.

  8. Possibilities of contactless investigation of vibrations at wind power plants; Moeglichkeiten der beruehrungslosen Schwingungsmessung an Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Behrendt, Reinhard [Polytec GmbH, Waldbronn/Berlin (Germany); Reimers, Ernst; Wiegers, Harald [Fachhochschule Flensburg (Germany)

    2010-07-01

    The laser-optical analysis of vibrations is an established procedure to the registration of oscillations of large structures such as buildings, bridges and power transmission lines over large distances of more than 100 m. The employment of this technology for the determination of the oscillation behaviour of rotor blades of the wind power plants particularly appears interesting. The employment of the laser measuring technique simplifies the sensory registration of rotor blade oscillations, since it comfortably can be carried out from the ground. Additionally, this laser measuring technology does not need pre-installed standard sensors in rotor blades. Test measurements at a 300 kW plant with a hub height of 50 m prove the suitability of the laser vibrometer for the registration of oscillations both with the standing rotor blade and in operation. For the evaluation of the deep natural frequencies an adjusting of the laser mark (tracking) on the rotating rotor blade is meaningful. The small frequency and the frequency dynamics of the wind power plants enable simple tracking systems. While with field surveys one-point-laser vibrometer are sufficient, scanning laser vibrometer are used for locally highly soluble 3D Scanning of the oscillation behaviour. Thus, for example structural defects or the position for contacting single sensors optimally can be determined by monitoring systems.

  9. An analytical investigation of the performance of wind-turbines with gyrocopter-like rotors

    Energy Technology Data Exchange (ETDEWEB)

    Kentfield, J.A.C.; Brophy, D.C. [Univ. of Calgary, Alberta (Canada)

    1997-12-31

    The performance was predicted of a wind-turbine, intended for electrical power generation, the rotor of which is similar in configuration to the rotor of an autogyro or gyrocopter as originated by Cierva. Hence the rotor axis of spin is tilted downwind, for maximum power production, by an angle of 40{degrees} to 50{degrees} relative to the vertical with power regulation by modulation of the tilt angle. Because the rotor of a Cierva turbine generates lift the simple, non-twisted, fixed-pitch blades {open_quotes}fly{close_quotes} and are self supporting thereby eliminating flap-wise bending moments when the blades are hinged at their roots. It was found from the analysis that it is possible to reduce tower bending moments substantially relative to a conventional horizontal axis turbine of equal power output and also, for equal maximum hub heights and blade tip altitudes, a Cierva turbine is capable, at a prescribed wind speed, of a greater power output than a conventional horizontal axis machine.

  10. Directional distribution of chilling winds in Estonia

    Science.gov (United States)

    Saue, Triin

    2016-08-01

    Wind chill equivalent temperature (WCET) is used to define thermal discomfort in winter months. Directional distributions of winds, which are associated with uncomfortable weather, were composed of three climatologically different Estonian locations: Vilsandi, Kuusiku, and Jõhvi. Cases with wind chill equivalent temperature Estonia: W, SW, and NW bring warm air in winter from the North Atlantic, while winds from the East-European plain (NE, E, and SE) are associated with cold air. The eastern prevalence was stronger when a lower threshold was used. A directional approach may find several applications, such as building, agricultural, landscape, or settlement planning.

  11. Available climatological and oceanographical data for site investigation program

    Energy Technology Data Exchange (ETDEWEB)

    Lindell, S.; Ambjoern, C.; Juhlin, B.; Larsson-McCann, S.; Lindquist, K. [Swedish Meteorological and Hydrological Inst., Norrkoeping (Sweden)

    2000-03-15

    Information on available data, measurements and models for climate, meteorology, hydrology and oceanography for six communities have been analysed and studied. The six communities are Nykoeping, Oesthammar, Oskarshamn, Tierp, Hultsfred and Aelvkarleby all of them selected by Svensk Kaernbraenslehantering AB, SKB, for a pre-study on possibilities for deep disposal of used nuclear fuel. For each of them a thorough and detailed register of available climatological data together with appropriate statistical properties are listed. The purpose is to compare the six communities concerning climatological and oceanographical data available and analyse the extent of new measurements or model applications needed for all of the selected sites. Statistical information on precipitation, temperature and runoff has good coverage in all of the six communities. If new information concerning any of these variables is needed in sites where no data collection exist today new installation can be made. Data on precipitation in form of snow and days with snow coverage is also available but to a lesser extent. This concerns also days with ground frost and average ground frost level where there is no fully representation of data. If more information is wanted concerning these variables new measurements or model calculations must be initiated. Data on freeze and break-up of ice on lakes is also insufficient but this variable can be calculated with good result by use of one-dimensional models. Data describing air pressure tendency and wind velocity and direction is available for all communities and this information should be sufficient for the purpose of SKB. This is also valid for the variables global radiation and duration of sunshine where no new data should be needed. Measured data on evaporation is normally not available in Sweden more than in special research basins. Actual evaporation is though a variable that easily can be calculated by use of models. There are many lakes in the six

  12. The climatology of dust aerosol over the arabian peninsula

    Directory of Open Access Journals (Sweden)

    A. Shalaby

    2015-01-01

    Full Text Available Dust storms are considered to be a natural hazard over the Arabian Peninsula, since they occur all year round with maximum intensity and frequency in Spring and Summer. The Regional Climate Model version 4 (RegCM4 has been used to study the climatology of atmospheric dust over the Arabian Peninsula from 1999 to 2012. This relatively long simulation period samples the meteorological conditions that determine the climatology of mineral dust aerosols over the Arabian Peninsula. The modeled Aerosol Optical Depth (AOD has been compared against ground-based observations of three Aerosol Robotic Network (AERONET stations that are distributed over the Arabian Peninsula and daily space based observations from the Multi-angle Imaging SpectroRadiometer (MISR, the Moderate resolution Imaging SpectroRadimeter (MODIS and Ozone Monitoring Instrument (OMI. The large scale atmospheric circulation and the land surface response that lead to dust uplifting have been analyzed. While the modeled AOD shows that the dust season extends from March to August with two pronounced maxima, one over the northern Arabian Peninsula in March with AOD equal to 0.4 and one over the southern Arabian Peninsula in July with AOD equal to 0.7, the observations show that the dust season extends from April to August with two pronounced maxima, one over the northern Arabian Peninsula in April with AOD equal to 0.5 and one over the southern Arabian Peninsula in July with AOD equal to 0.5. In spring a high pressure dominates the Arabian Peninsula and is responsible for advecting dust from southern and western part of the Arabian Peninsula to northern and eastern part of the Peninsula. Also, fast developed cyclones in northern Arabian Peninsula are responsible for producing strong dust storms over Iraq and Kuwait. However, in summer the main driver of the surface dust emission is the strong northerly wind ("Shamal" that transport dust from the northern Arabian Peninsula toward south parallel

  13. Wake Characteristics of a Single Turbine During the CWEX-10/11 Crop Wind-Energy EXperiments

    Science.gov (United States)

    Rajewski, D. A.; Takle, E. S.; Lundquist, J. K.; Rhodes, M. E.; Prueger, J. H.; Oncley, S. O.; Horst, T. W.; Pfeiffer, R.; Hatfield, J.; Spoth, K. K.; Doorenbos, R. K.

    2013-12-01

    In the summer of 2010 and 2011 for the Crop Wind-energy EXperiment (CWEX), flux stations measured differences in micrometeorology upstream and downstream of a single turbine within a large wind farm in Iowa. Profiling LiDARs were positioned upwind and downwind of a single turbine for two months in 2011 to document the wake profiles of mean wind speed and turbulent kinetic energy (TKE). Nacelle-based measurements of wind speed, wind direction, and power produced verified the likely presence of a wake above the downwind flux station. As described in the CWEX overview paper (Rajewski et al. 2013) the flux stations detected (1) turbine-wake events for wakes overhead but not intersecting the surface, (2) wakes with a direct surface influence, and (3) flow perturbations caused by the static pressure field around a line of turbines. We refine our conceptual model of wind turbine flow by comparing downwind-upwind flux and profile station differences for categories of waked and non-waked flow according to turbine hub-height speed and direction, ambient thermal stratification, and the operating status of the turbines. For nighttime stable conditions (some for which a low level jet is present) we measured both within the rotor depth and at the surface higher turbulence and stronger intermittency of the flow on the wake edges as compared to the wake core. We additionally observe frequent periods with 20-30° of directional shear from the surface to the top of the rotor as evidenced by a downwind flux station in non-waked flow with concurrent LiDAR measurement of a wake in the rotor layer. Momentum power spectra and co-spectra of 20-Hz surface data corroborate with previous wind tunnel and numerical simulations of wake turbulence with higher energy intensity but at reduced scales than for non-waked conditions. The spectra demonstrate a return to ambient flow when the wind farm is brought offline.

  14. Synoptic versus regional causes of icing on wind turbines at an exposed wind farm site in Germany

    Science.gov (United States)

    Weissinger, Maximilian; Strauss, Lukas; Serafin, Stefano; Dorninger, Manfred; Burchhart, Thomas; Fink, Martin

    2017-04-01

    Ice accretion on wind turbine blades can lead to significant power production loss or even permanent structural damage on the turbine. With the ongoing construction of wind farms at sites with increased icing potential in cold climates, accurate icing predictions are needed to optimise power plant operation. To this end, the frequency of occurrence and the causes of meteorological icing need to be better understood. The project ICE CONTROL, an Austrian research initiative, aims to improve icing forecasts through measurements, probabilistic forecasting, and verification of icing on wind turbine blades. The project focuses on a wind farm site near Ellern, Germany, located on the Hunsrück, a hilly terrain rising above the surrounding plain by 200-300 metres. Production data from the last three winters show that icing events tend to occur more often at the wind turbines on top of the highest hills. The present study aims to investigate historical cases of wind turbine icing and their meteorological causes at the Ellern wind farm. The data available consists of a three-year period (2013-2016) of operational data from the Ellern wind farm as well as meteorological measurements at nearby stations operated by the German Weather Service (DWD). In addition, radiosondes and weather charts are taken into account. The main objective of this work is, first, to link the local and regional weather conditions to larger-scale weather patterns and prevailing air masses, and second, to determine the types of icing (in-cloud vs. freezing precipation). Results show that in most icing cases the cloud base height was below the hub height while the temperature was just below the freezing point. Precipitation was absent in most cases. This suggests that most of the observed icing events were due to in-cloud icing. Icing conditions occurred often (but not exclusively) under specific synoptic-scale weather conditions, such as north-westerly flow advecting maritime polar air masses to Central

  15. Nature and climatology of Pfänderwind

    Directory of Open Access Journals (Sweden)

    Alexander Gohm

    2015-04-01

    Full Text Available The characteristics and climatology of Pfänderwind, a largely unknown downslope windstorm near the town of Bregenz (Austria at the entrance of the Rhine Valley, are investigated based on an eleven-year dataset of weather station observations and ERA-Interim reanalyses. The goal is to clarify the inconsistency in the definition of this phenomenon, to illuminate its dynamics, and to quantify its frequency of occurrence. It is shown that Pfänderwind has similarities to foehn but does occur for different synoptic-scale conditions. Moreover, two types of Pfänderwind have to be distinguished: Type 1, or classical Pfänderwind, is associated with easterly to northeasterly large-scale flow that crosses the Pfänder mountain range, descends in a foehn-like manner and causes moderate to strong winds in the town of Bregenz and its vicinity. The temperature anomaly induced at the surface by adiabatic warming is small as a result of weak low-level stability. Type-1 events occur on average 12 times per year, preferentially in spring, and most frequently between the afternoon and midnight. Type 2, or southeast Pfänderwind, is associated with westerly to southwesterly ambient winds near the main Alpine crest level. The Rhine valley is filled with cold air and in most cases south foehn is not present. However, the synoptic and meso-scale pressure gradient favours southerly ageostrophic flow in the Rhine Valley especially near the top of the cold-air pool. This flow passes the Gebhardsberg, the southwestern extension of the Pfänder mountain range, descends on its leeward side and causes strong foehn-like warming at the surface. However, southerly to southeasterly near-surface winds at Bregenz are rather weak. Type-2 events occur on average 40 times per year, most frequently between the evening and the early morning, and exhibit a weak seasonal dependence. More than half of all type-1 and type-2 events last only one or two hours.

  16. On reconstruction of time series in climatology

    Directory of Open Access Journals (Sweden)

    V. Privalsky

    2015-10-01

    Full Text Available The approach to time series reconstruction in climatology based upon cross-correlation coefficients and regression equations is mathematically incorrect because it ignores the dependence of time series upon their past. The proper method described here for the bivariate case requires the autoregressive time- and frequency domains modeling of the time series which contains simultaneous observations of both scalar series with subsequent application of the model to restore the shorter one into the past. The method presents further development of previous efforts taken by a number of authors starting from A. Douglass who introduced some concepts of time series analysis into paleoclimatology. The method is applied to the monthly data of total solar irradiance (TSI, 1979–2014, and sunspot numbers (SSN, 1749–2014, to restore the TSI data over 1749–1978. The results of the reconstruction are in statistical agreement with observations.

  17. A hemispheric climatology of monsoon depressions

    Science.gov (United States)

    Hurley, J. V.; Boos, W.

    2012-12-01

    Monsoon depressions are large (1000-2000 km diameter) cyclonic low pressure systems having organized deep convection, best known for forming in the Bay of Bengal and migrating northwest over northern India in the monsoon trough. About 3 to 5 of these systems occur during each monsoon season, contributing about half of the Indian summer rainfall. Despite their importance as a precipitation source, their dynamics are poorly constrained. Furthermore, although they do occur elsewhere, such as around Australia and in the southern Indian Ocean, there does not exist a collective inventory of these systems outside of the Bay of Bengal region. Here we present a climatology of monsoon depressions produced from the ERA-Interim Reanalysis. Feature tracks are identified using an automated tracking algorithm (K. Hodges' TRACK code) applied to the 850 hPa relative vorticity field for local summer, 1989 to 2003. Using criteria based on relative vorticity and sea level pressure, cyclonic low pressure systems are separated into different intensity categories, one of which corresponds to the definition for monsoon depressions used by the India Meteorological Department. The resultant distribution of storms obtained for the Bay of Bengal region compares well with a previously compiled climatology of monsoon depressions that was limited to the region surrounding India. Having validated our ability to identify monsoon depressions in their classic genesis region near India, we then extend the methods to include the western Pacific, Australia, and the southern Indian Ocean. Track distributions and composite structures of monsoon depressions for these different regions will be presented.

  18. Observation Targeting for the Tehachapi Pass and Mid-Columbia Basin: WindSENSE Phase III Project Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, D

    2011-10-22

    The overall goal of this multi-phased research project known as WindSENSE is to develop an observation system deployment strategy that would improve wind power generation forecasts. The objective of the deployment strategy is to produce the maximum benefit for 1- to 6-hour ahead forecasts of wind speed at hub-height ({approx}80 m). In Phase III of the project, the focus was on the Mid-Columbia Basin region which encompasses the Bonneville Power Administration (BPA) wind generation area shown in Figure 1 that includes Klondike, Stateline, and Hopkins Ridge wind plants. The typical hub height of a wind turbine is approximately 80-m above ground level (AGL). So it would seem that building meteorological towers in the region upwind of a wind generation facility would provide data necessary to improve the short-term forecasts for the 80-m AGL wind speed. However, this additional meteorological information typically does not significantly improve the accuracy of the 0- to 6-hour ahead wind power forecasts because processes controlling wind variability change from day-to-day and, at times, from hour-to-hour. It is also important to note that some processes causing significant changes in wind power production function principally in the vertical direction. These processes will not be detected by meteorological towers at off-site locations. For these reasons, it is quite challenging to determine the best type of sensors and deployment locations. To address the measurement deployment problem, Ensemble Sensitivity Analysis (ESA) was applied in the Phase I portion of the WindSENSE project. The ESA approach was initially designed to produce spatial fields that depict the sensitivity of a forecast metric to a set of prior state variables selected by the user. The best combination of variables and locations to improve the forecast was determined using the Multiple Observation Optimization Algorithm (MOOA) developed in Phase I. In Zack et al. (2010a), the ESA-MOOA approach was

  19. A climatological study of rural surface ozone in central Greece

    Directory of Open Access Journals (Sweden)

    P. D. Kalabokas

    2004-01-01

    Full Text Available Recent studies show that surface ozone levels at rural sites in Greece are generally high when compared with rural ozone measurements at northern European sites. The area of SE Europe, including Greece, is not very well monitored regarding rural ozone in comparison to central and northern Europe. In order to have the best possible picture of the rural surface ozone climatology in the area, based on the available data-sets of long-term continuous monitoring stations, the 10-year measurement records (1987-1996 of the Athens peripheral station of Liossia, (12 km N of the city center and the urban background station of Geoponiki (3 km W as well as the 4-year record (1996-1999 of the rural station of Aliartos (100 km NW of Athens, are analyzed in this paper. The data for Liossia and Geoponiki stations are screened for cases of strong airflow from rural areas (N-NE winds stronger than 5 m/s. The variation characteristics of the average rural ozone afternoon levels (12:00-18:00, with the best vertical atmospheric mixing, are mainly examined since these measurements are expected to be representative of the broader area. In all three stations there is a characteristic seasonal variation of rural ozone concentrations with lowest winter afternoon values at about 50 μg/m3 in December-January and average summer afternoon values at about 120 μg/m3 in July-August, indicating that high summer values are observed all over the area. The rural summer afternoon ozone values are very well correlated between the three stations, implying spatial homogeneity all over the area but also temporal homogeneity, since during the 13-year period 1987-1999 the rural afternoon ozone levels remained almost constant around the value of 120 μg/m3.

  20. Wind shear coefficients, roughness length and energy yield over coastal locations in Southern Italy

    Energy Technology Data Exchange (ETDEWEB)

    Gualtieri, Giovanni [Research National Council-Institute for Biometeorology (CNR-IBIMET), Via Caproni 8, 50145 Firenze (Italy); Secci, Sauro [Fedi Impianti Srl, Via Caduti di Cefalonia, 31, 50127 Firenze (Italy)

    2011-03-15

    In the present work a computation of wind shear coefficients (WSCs) based on 1-h measured wind data has been performed by three stations located over coastal sites in Southern Italy, i.e., Brindisi (BR), Portoscuso (PS) and Termini Imerese (TI). Wind observations have been collected through a 6-year period (January 1, 1997 to December 31, 2002) by wind mast recording at the same two sensor heights (i.e., 10 and 50 m AGL), thus enabling a proper wind profile analysis. WSC overall mean values were found to be 0.271 at BR, 0.232 at PS, and 0.150 at TI. In addition, a detailed analysis has been carried out to describe the WSC yearly, monthly and diurnal variation, as well as by wind direction. The characteristics of z{sub 0} surface roughness length have been also investigated as an estimate for neutral stability conditions only, resulting in overall mean values of 0.526 m at BR, 0.287 m at PS, and 0.027 m at TI. The z{sub 0} variation by year, month and hour of the day, as well as by wind direction, has been analysed, too. The European ''Corine Land Cover 2000'' classification of the study areas has been employed to deeply investigate the land use influence on both WSC and z{sub 0} characteristics as a function of wind direction. Based on temperature and pressure surface measurements, the computation of site-specific mean air density as well as monthly variation has been also performed. Site-related 50-m wind resource has been assessed by means of wind roses and wind speed frequency distributions, as well as Weibull's parameters. The potential turbine-converted wind energy yield has been also investigated, enabling to detect, for each site, the most suitable 50-m hub height turbine model regardless of its rated power. Furthermore, a number of comparisons have been made to assess the discrepancy in 50-m energy yield resulting if using data extrapolated from 10 m, both with 0.143 default and overall mean WSC value, instead of actually 50-m

  1. Locations and attributes of wind turbines in New Mexico, 2011

    Science.gov (United States)

    Carr, Natasha B.; Diffendorfer, James B.; Fancher, Tammy; Hawkins, Sarah J.; Latysh, Natalie; Leib, Kenneth J.; Matherne, Anne Marie

    2013-01-01

    This dataset represents an update to U.S. Geological Survey Data Series 596. Locations and attributes of wind turbines in New Mexico, 2009 (available at http://pubs.usgs.gov/ds/596/).This updated New Mexico wind turbine Data Series provides geospatial data for all 562 wind turbines established within the State of New Mexico as of June 2011, an increase of 155 wind turbines from 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, county, and development status of wind turbine. Wind energy facility data for each turbine include: facility name, facility power capacity, number of turbines associated with each facility to date, facility developer, facility ownership, and year the facility went online. The locations of turbines are derived from 1-meter true-color aerial photographs produced by the National Agriculture Imagery Program (NAIP); the photographs have a positional accuracy of about ±5 meters. The locations of turbines constructed during or prior to August 2009 are based on August 2009 NAIP imagery and turbine locations constructed after August 2009 were based June 2011 NAIP imagery. The location of turbines under construction during June 2011 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas developed by the U.S. Geological Survey (http://my.usgs.gov/eerma/). The Energy Atlas synthesizes data on existing and potential energy development in Colorado and New Mexico and includes additional natural resource data layers. This information may be used by decisionmakers to evaluate and compare the potential benefits and tradeoffs associated with different energy development strategies or scenarios. Interactive maps, downloadable data layers, comprehensive metadata, and decision-support tools also are included in the Energy Atlas. The format of the Energy

  2. Locations and attributes of wind turbines in Colorado, 2011

    Science.gov (United States)

    Carr, Natasha B.; Diffendorfer, James E.; Fancher, Tammy; Hawkins, Sarah J.; Latysh, Natalie; Leib, Kenneth J.; Matherne, Anne Marie

    2013-01-01

    This dataset represents an update to U.S. Geological Survey Data Series 597. Locations and attributes of wind turbines in Colorado, 2009 (available at http://pubs.usgs.gov/ds/597/). This updated Colorado wind turbine Data Series provides geospatial data for all 1,204 wind turbines established within the State of Colorado as of September 2011, an increase of 297 wind turbines from 2009. Attributes specific to each turbine include: turbine location, manufacturer and model, rotor diameter, hub height, rotor height, potential megawatt output, land ownership, county, and development status of the wind turbine. Wind energy facility data for each turbine include: facility name, facility power capacity, number of turbines associated with each facility to date, facility developer, facility ownership, and year the facility went online. The locations of turbines are derived from 1-meter true-color aerial photographs produced by the National Agriculture Imagery Program (NAIP); the photographs have a positional accuracy of about ±5 meters. Locations of turbines constructed during or prior to August 2009 are based on August 2009 NAIP imagery and turbine locations constructed after August 2009 were based on September 2011 NAIP imagery. The location of turbines under construction during September 2011 likely will be less accurate than the location of existing turbines. This data series contributes to an Online Interactive Energy Atlas developed by the U.S. Geological Survey (http://my.usgs.gov/eerma/). The Energy Atlas synthesizes data on existing and potential energy development in Colorado and New Mexico and includes additional natural resource data layers. This information may be used by decisionmakers to evaluate and compare the potential benefits and tradeoffs associated with different energy development strategies or scenarios. Interactive maps, downloadable data layers, comprehensive metadata, and decision-support tools also are included in the Energy Atlas. The format of

  3. A Climatology of Central American Gyres

    Science.gov (United States)

    Papin, P. P.; Griffin, K. S.; Bosart, L. F.; Torn, R. D.

    2012-12-01

    Monsoon gyres, commonly found over the western Pacific Ocean, are characterized by broad low-level cyclonic circulations that occur at a variety of spatial scales ranging from 1500-3000 km. Low-level cyclonic gyre circulations, while less frequent and occupying a smaller scale, have also been observed over Central America during the tropical cyclone (TC) season. A noteworthy gyre observed during the 2010 PREDICT field project served as a "collector" of TC Matthew and a source for TC Nicole. During October 2011, devastating flooding occurred in Guatemala and El Salvador when TD 12-E, embedded in a gyre circulation, made landfall on the Pacific coast of Central America. These gyre occurrences, their apparent links to TC activity, and their association with high-impact weather motivates this presentation. A preliminary analysis of Central American gyres suggests that their spatial scales vary between 1000-2000 km. These gyres also tend to be co-located with reservoirs of deep moisture that are characterized by high precipitable water values (>50 mm) and embedded deep convection on their southern and eastern sides. Catastrophic flooding can occur when gyre cyclonic circulations interact with the topography of Central America. A Central American gyre climatology including gyre frequency over the TC season and individual gyre duration will be presented. This climatology is then used to craft a gyre composite using previous gyre cases from 1980-2010. Particular attention will be given to the common synoptic and sub-synoptic scale features that precede and take place during gyre formation. This includes the role that intraseasonal and interannual circulations such as the Madden-Julian Oscillation (MJO) and El Nino-Southern Oscillation (ENSO) might play in gyre development. TC genesis events within gyre circulations will also be highlighted and examined further. Finally, the results of a September 2010 case study will be used to illustrate the impact that Central American

  4. Lightning climatology in the Congo Basin

    Science.gov (United States)

    Soula, S.; Kasereka, J. Kigotsi; Georgis, J. F.; Barthe, C.

    2016-09-01

    The lightning climatology of the Congo Basin including several countries of Central Africa is analysed in detail for the first time. It is based on data from the World Wide Lightning Location Network (WWLLN), for the period from 2005 to 2013. A comparison of these data with Lightning Imaging Sensor (LIS) data for the same period shows the relative detection efficiency of the WWLLN (DE) in the 2500 km × 2500 km region increases from about 1.70% in the beginning of the period to 5.90% in 2013, and it is in agreement with previous results for other regions of the world. However, the increase of DE is not uniform over the whole region. The average monthly flash rate describes an annual cycle with a strong activity from October to March and a low one from June to August, associated with the ITCZ migration but not exactly symmetrical on both sides of the equator. The zonal distribution of the lightning flashes exhibits a maximum between 1°S and 2°S and about 56% of the flashes are located south of the equator in the 10°S-10°N interval. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, according to the reference year. The annual flash density and number of stormy days show a sharp maximum localized in the eastern part of Democratic Republic of Congo (DRC) regardless of the reference year and the period of the year. These maxima reach 12.86 fl km- 2 and 189 days, respectively, in 2013, and correspond to a very active region located at the rear of the Virunga mountain range at altitudes that exceed 3000 m. The presence of these mountains plays a role in the thunderstorm development along the year. The estimation of this local maximum of the lightning density by taking into account the DE, leads to a value consistent with that of the global climatology by Christian et al. (2003).

  5. Experimental evidence for the effect of small wind turbine proximity and operation on bird and bat activity.

    Directory of Open Access Journals (Sweden)

    Jeroen Minderman

    Full Text Available The development of renewable energy technologies such as wind turbines forms a vital part of strategies to reduce greenhouse gas emissions worldwide. Although large wind farms generate the majority of wind energy, the small wind turbine (SWT, units generating <50 kW sector is growing rapidly. In spite of evidence of effects of large wind farms on birds and bats, effects of SWTs on wildlife have not been studied and are likely to be different due to their potential siting in a wider range of habitats. We present the first study to quantify the effects of SWTs on birds and bats. Using a field experiment, we show that bird activity is similar in two distance bands surrounding a sample of SWTs (between 6-18 m hub height and is not affected by SWT operation at the fine scale studied. At shorter distances from operating turbines (0-5 m, bat activity (measured as the probability of a bat "pass" per hour decreases from 84% (71-91% to 28% (11-54% as wind speed increases from 0 to 14 m/s. This effect is weaker at greater distances (20-25 m from operating turbines (activity decreases from 80% (65-89% to 59% (32-81%, and absent when they are braked. We conclude that bats avoid operating SWTs but that this effect diminishes within 20 m. Such displacement effects may have important consequences especially in landscapes where suitable habitat is limiting. Planning guidance for SWTs is currently lacking. Based on our results we recommend that they are sited at least 20 m away from potentially valuable bat habitat.

  6. Experimental evidence for the effect of small wind turbine proximity and operation on bird and bat activity.

    Science.gov (United States)

    Minderman, Jeroen; Pendlebury, Chris J; Pearce-Higgins, James W; Park, Kirsty J

    2012-01-01

    The development of renewable energy technologies such as wind turbines forms a vital part of strategies to reduce greenhouse gas emissions worldwide. Although large wind farms generate the majority of wind energy, the small wind turbine (SWT, units generating wind farms on birds and bats, effects of SWTs on wildlife have not been studied and are likely to be different due to their potential siting in a wider range of habitats. We present the first study to quantify the effects of SWTs on birds and bats. Using a field experiment, we show that bird activity is similar in two distance bands surrounding a sample of SWTs (between 6-18 m hub height) and is not affected by SWT operation at the fine scale studied. At shorter distances from operating turbines (0-5 m), bat activity (measured as the probability of a bat "pass" per hour) decreases from 84% (71-91%) to 28% (11-54%) as wind speed increases from 0 to 14 m/s. This effect is weaker at greater distances (20-25 m) from operating turbines (activity decreases from 80% (65-89%) to 59% (32-81%)), and absent when they are braked. We conclude that bats avoid operating SWTs but that this effect diminishes within 20 m. Such displacement effects may have important consequences especially in landscapes where suitable habitat is limiting. Planning guidance for SWTs is currently lacking. Based on our results we recommend that they are sited at least 20 m away from potentially valuable bat habitat.

  7. Sprite Climatology in the Eastern Mediterranean Region

    Science.gov (United States)

    Yair, Yoav; Price, Colin; Katzenelson, Dor; Rosenthal, Neta; Rubanenko, Lior; Ben-Ami, Yuval; Arnone, Enrico

    2015-04-01

    We present statistical analysis of 436 sprites observed in 7 winter campaigns from 2006/7-2012/13. Results show a clear peak in the frequency of sprite detections, with maximum values (reports of winter sprites over the Sea of Japan and summer ones in central Europe. Other shapes such as trees, wishbones, etc. appear quite rarely. Single element events constitute 16.5% of observations, with 83.5% containing 2 elements or more. Clusters of homogeneous types are slightly more frequent than mixed ones (55%). Our observations suggest winter East Mediterranean thunderstorms to have a vertical structure that is an intermediate type between high tropical convective systems and the lower cloud-top cells in winter thunderstorms over the Sea of Japan. The climatology shows that the Eastern Mediterranean is a major sprite producer during Northern Hemisphere winter, and thus the existing and future optical observation infrastructure in Israel offers ground-based coverage for upcoming space missions that aim to map global sprite activity.

  8. Global Historical Climatology Network - Daily (GHCN-Daily), Version 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Historical Climatology Network - Daily (GHCN-Daily) dataset integrates daily climate observations from approximately 30 different data sources. Version 3...

  9. Global Precipitation Climatology Project (GPCP) - Pentad, Version 2.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products. The Version 2.2 Pentad product covers the period January 1979 to the present,...

  10. Global Precipitation Climatology Project (GPCP) - Monthly, Version 2.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products with the two primary products being the monthly satellite-gauge and associated...

  11. Historical Climatology In Europe. The State Of The Art

    Energy Technology Data Exchange (ETDEWEB)

    Brazdil, R. [Institute of Geography, Masaryk University, Kotlarska 2, CZ-611 37 Brno (Czech Republic); Pfister, C. [Institute of History/NCCR Climate, University of Bern, Unitobler, CH-3000 Bern 9 (Switzerland); Wanner, H.; Luterbacher, J. [NCCR Climate, University of Bern, Hallerstrasse 12, CH-3012 Bern (Switzerland); Von Storch, H. [GKSS-Research-Center, Max Planck Strasse 1, D-21502 Geesthacht (Germany)

    2005-06-01

    This paper discusses the state of European research in historical climatology. This field of science and an overview of its development are described in detail. Special attention is given to the documentary evidence used for data sources, including its drawbacks and advantages. Further, methods and significant results of historical-climatological research, mainly achieved since 1990, are presented. The main focus concentrates on data, methods, definitions of the 'Medieval Warm Period' and the 'Little Ice Age', synoptic interpretation of past climates, climatic anomalies and natural disasters, and the vulnerability of economies and societies to climate as well as images and social representations of past weather and climate. The potential of historical climatology for climate modelling research is discussed briefly. Research perspectives in historical climatology are formulated with reference to data, methods, interdisciplinarity and impacts.

  12. AFSC/ABL: Auke Bay Climatology 1959-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data set includes available climatological and related physical environmental records for Auke Bay, Auke Creek and Auke Lake beginning in 1959. Daily high and low...

  13. Global Precipitation Climatology Project (GPCP) - Daily, Version 1.2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Precipitation Climatology Project (GPCP) comprises a total of 27 products. The Version 1.2 Daily product covers the period October 1998 to the present,...

  14. Global Historical Climatology Network - Monthly (GHCN-M), Version 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Since the early 1990s the Global Historical Climatology Network-Monthly (GHCN-M) dataset has been an internationally recognized source of data for the study of...

  15. Wind climate estimation using WRF model output: method and model sensitivities over the sea

    DEFF Research Database (Denmark)

    Hahmann, Andrea N.; Vincent, Claire Louise; Peña, Alfredo

    2015-01-01

    setup parameters. The results of the year-long sensitivity simulations show that the long-term mean wind speed simulated by the WRF model offshore in the region studied is quite insensitive to the global reanalysis, the number of vertical levels, and the horizontal resolution of the sea surface......High-quality tall mast and wind lidar measurements over the North and Baltic Seas are used to validate the wind climatology produced from winds simulated by the Weather, Research and Forecasting (WRF) model in analysis mode. Biases in annual mean wind speed between model and observations at heights...... around 100m are smaller than 3.2% at offshore sites, except for those that are affected by the wake of a wind farm or the coastline. These biases are smaller than those obtained by using winds directly from the reanalysis. We study the sensitivity of the WRF-simulated wind climatology to various model...

  16. The Association of Large-Scale Climate Variability and Teleconnections on Wind Energy Resource over Europe and its Intermittency

    Science.gov (United States)

    Kriesche, Pascal; Schlosser, C. Adam

    2014-05-01

    In times of increasing importance of wind power in the world's energy mix, this study focuses on a better understanding of the influences of large-scale climate variability on wind power resource over Europe from 34°N to 71,5°N latitudes and from 11°E to 41°W longitudes. The impact of the North Atlantic Oscillation, the Arctic Oscillation, the El Niño Southern Oscillation and the Atlantic Multidecadal Oscillation are investigated in terms of their correlation with wind power density at 80 m hub height. These wind power densities are calculated based on the MERRA Reanalysis data set covering 31 years of measurements with a time resolution of an hour and a spatial resolution of 1/2° latitudes 2/3° longitudes. Not surprisingly, the Arctic Oscillation and the North Atlantic Oscillation are highly correlated with the time series of wind power density, especially for northern Europe. This correlation can also be found in the first principal component of a Principal Component Analysis of wind power density over Europe explaining 14% of the overall variance. Coefficient of determination studies for linear regression between wind power density time series and the teleconnections reveal that for northern Europe up to 30% of the variation of wind power density can be explained by the North Atlantic Oscillation, for example. Further, cross-correlation analyses indicate the strongest associated variations are achieved with the Arctic Oscillation and the North Atlantic Oscillation leading wind power density by at most one day. Furthermore, the impact of high and low phases of the respective oscillations has been assessed to provide a more comprehensive illustration. In the case of high Arctic and North Atlantic Oscillation, wind power density can vary by a factor of three in northern Europe between negative and positive phases, and a similar effect (but opposite in sign) is seen for southern Europe, with wind power density varying by a factor of two. Similar results are

  17. Using Satellite SAR to Characterize the Wind Flow around Offshore Wind Farms

    Directory of Open Access Journals (Sweden)

    Charlotte Bay Hasager

    2015-06-01

    Full Text Available Offshore wind farm cluster effects between neighboring wind farms increase rapidly with the large-scale deployment of offshore wind turbines. The wind farm wakes observed from Synthetic Aperture Radar (SAR are sometimes visible and atmospheric and wake models are here shown to convincingly reproduce the observed very long wind farm wakes. The present study mainly focuses on wind farm wake climatology based on Envisat ASAR. The available SAR data archive covering the large offshore wind farms at Horns Rev has been used for geo-located wind farm wake studies. However, the results are difficult to interpret due to mainly three issues: the limited number of samples per wind directional sector, the coastal wind speed gradient, and oceanic bathymetry effects in the SAR retrievals. A new methodology is developed and presented. This method overcomes effectively the first issue and in most cases, but not always, the second. In the new method all wind field maps are rotated such that the wind is always coming from the same relative direction. By applying the new method to the SAR wind maps, mesoscale and microscale model wake aggregated wind-fields results are compared. The SAR-based findings strongly support the model results at Horns Rev 1.

  18. A hail climatology in South Korea

    Science.gov (United States)

    Jin, Han-Gyul; Lee, Hyunho; Lkhamjav, Jambajamts; Baik, Jong-Jin

    2017-05-01

    A hail observation dataset for 1972-2013 is analyzed to examine the temporal and spatial distributions of hail occurrence in South Korea. Furthermore, using radiosonde data, three thermodynamic factors which are 700-500 hPa temperature lapse rate, water vapor mixing ratio in the lowest 100 hPa, and convective available potential energy (CAPE) and one dynamic factor which is 0-6 km bulk wind shear are calculated and their correlations with hail occurrence in South Korea are examined. Hail days per year in South Korea show a decreasing trend. The monthly variation of hail days exhibits double peaks in April and November. The minimum value of hail days appears in August, which is related to the high freezing-level height, the small midlevel temperature lapse rate, and the weak bulk wind shear. During a day, 44% of the whole hail events occur between 1200 and 1800 local standard time. Spatially, hail primarily occurs in the west coastal area and the east mountainous area of South Korea. Both the regions exhibit double peaks in the monthly variation of hail days, but the east mountainous area exhibits the later spring peak (May) and the lower hail frequency in late autumn compared to the west coastal area. The midlevel temperature lapse rate is strongly correlated with the monthly variation of hail occurrence. Hail is likely to occur when the low-level water vapor mixing ratio is in the range of 3-6 g kg- 1. CAPE is not strongly correlated with hail occurrence. The strong bulk wind shear is correlated with hail occurrence. The bulk wind shear is decreasing and the freezing-level height is increasing annually, which contributes to the annual decrease of hail occurrence.

  19. Comparison of calculation methods for wind shear exponent in complex terrain at altitude above 1000 meters%海拔1000 m以上复杂地形风能风切变指数算法比较

    Institute of Scientific and Technical Information of China (English)

    邓胜祥; 陈刚; 陈桂宝

    2015-01-01

    Among all uncertainty factors affecting the wind power assessment at a site, wind speed extrapolation is probably one of the most critical, particularly if considering the increasing of the size of modern multi-Megawatt wind turbines, and therefore of their hub height. Wind measurements are generally performed below wind turbine hub heights due to avoiding higher measurement and tower costs. In order to obtain the wind speed at the hub height of the turbine, the measurements are extrapolated, assuming that the wind shear exponent is constant. So it is important to calculate the wind shear exponent accurately. The wind shear exponents of different areas are different because of the influence of roughness. What’s more, the wind shear exponent may change in the same area at different time. Therefore, to obtain an accurate value of the wind shear exponent in a certain area at a certain time, only the local wind speed data can be used to calculate it. Here, the situation is set as some complex terrain above 1000 meters. There are many different methods to calculate the wind shear exponent, and in this paper, four different methods are chosen, which are:the Panofsky and Dutton (PD) method, annual average wind speed method, wind profile method and all of the data method. The PD method is based on Monin-Obukhov similarity theory, and Panofsky and Dutton proposed the semiempirical formulation to estimate the wind shear exponent as a function of stability and roughness. First of all, according to the classification method of Pasquill, the stability can be calculated. Then, choose the right formulation based on the value of stability to calculate the wind shear exponent. Method 2 and 4 use the wind speed and the exponential formula to calculate wind shear exponent. Method 3 uses wind profile fitting to calculate the wind shear exponent. Choose the example of actual wind speed data within a complete year on three wind measurement heights at an anemometer tower of some

  20. Odin stratospheric proxy NOy measurements and climatology

    Directory of Open Access Journals (Sweden)

    D. Murtagh

    2008-10-01

    Full Text Available Five years of OSIRIS (Optical Spectrograph and InfraRed Imager System NO2 and SMR (Sub-millimetre and Millimetre Radiometer HNO3 observations from the Odin satellite, combined with data from a photochemical box model, have been used to construct a stratospheric proxy NOy data set including the gases: NO, NO2, HNO3, 2×N2O5 and ClONO2. This Odin NOy climatology is based on all daytime measurements and contains monthly mean and standard deviation, expressed as mixing ratio or number density, as function of latitude or equivalent latitude (5° bins on 17 vertical layers (altitude, pressure or potential temperature between 14 and 46 km. Comparisons with coincident NOy profiles from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS instrument were used to evaluate several methods to combine Odin observations with model data. This comparison indicates that the most appropriate merging technique uses OSIRIS measurements of NO2, scaled with model NO/NO2 ratios, to estimate NO. The sum of 2×N2O5 and ClONO2 is estimated from uncertainty-based weighted averages of scaled observations of SMR HNO3 and OSIRIS NO2. Comparisons with ACE-FTS suggest the precision (random error and accuracy (systematic error of Odin NOy profiles are about 15% and 20%, respectively. Further comparisons between Odin and the Canadian Middle Atmosphere Model (CMAM show agreement to within 20% and 2 ppb throughout most of the stratosphere except in the polar vortices. The combination of good temporal and spatial coverage, a relatively long data record, and good accuracy and precision make this a valuable NOy product for various atmospheric studies and model assessments.

  1. Odin stratospheric proxy NOy measurements and climatology

    Directory of Open Access Journals (Sweden)

    D. Murtagh

    2008-03-01

    Full Text Available Five years of OSIRIS (Optical Spectrograph and InfraRed Imager System NO2 and SMR (Sub-Millimetre Radiometer HNO3 observations from the Odin satellite, combined with data from a photochemical box model, have been used to construct a stratospheric proxy NOy data set including the gases: NO, NO2, HNO3, 2×N2O5 and CIONO2. This Odin NOy climatology is based on all daytime measurements and contains monthly mean and standard deviation, expressed as mixing ratio or number density, as function of latitude or equivalent latitude (5° bins on 17 vertical layers (altitude, pressure or potential temperature between 14 and 46 km. Comparisons with coincident NOy profiles from the Atmospheric Chemistry Experiment–Fourier Transform Spectrometer (ACE-FTS instrument were used to evaluate several methods to combine Odin observations with model data. This comparison indicates that the most appropriate merging technique uses OSIRIS measurements of NO2, scaled with model NO/NO2 ratios, to estimate NO. The sum of 2×N2O5 and CIONO2 is estimated from uncertainty-based weighted averages of scaled observations of SMR HNO3 and OSIRIS NO2. Comparisons with ACE-FTS suggest the precision (random error and accuracy (systematic error of Odin NOy profiles are about 15% and 20%, respectively. Further comparisons between Odin and the Canadian Middle Atmosphere Model (CMAM show agreement to within 20% and 2 ppb throughout most of the stratosphere except in the polar vortices. A particularly large disagreement within the Antarctic vortex in the upper stratosphere during spring indicates too strong descent of air in CMAM. The combination of good temporal and spatial coverage, a relatively long data record, and good accuracy and precision make this a valuable NOy product for various atmospheric studies and model assessments.

  2. A soil moisture climatology of Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Hollinger, S.E.; Isard, S.A. (Illinois State Water Survey, Champaign, IL (United States) Univ. of Illinois, Urbana, IL (United States))

    1994-05-01

    Ten years of soil moisture measurements (biweekly from March through September and monthly during winter) within the top 1 m of soil at 17 grass-covered sites across Illinois are analyzed to provide a climatology of soil moisture for this important Midwest agricultural region. Soil moisture measurements were obtained with neutron probes that were calibrated for each site. Measurement errors are dependent upon the volumetric water content with errors less than 20 percent when soil moisture is above 0 percent of soil volume. Single point errors in moisture measurements from the top 1 m of soil range from 6 percent to 13 percent when volumetric soil moisture is 30 percent of soil volume. The average depletion in moisture between winter and summer over the 10-year period for the top 2 m of soil in Illinois was 72.3 mm. Three-quarters of this decrease occurred above 0.5 m and only 5 percent occurred between the 1.0-m and 2.0-m depths. The average moisture decrease between winter and summer during a wet year (1985) and a drought year (1988) in the top 2 m of soil was 64 percent and 204 percent of the average for the 10-year period, respectively. Seasonal means in soil moisture averaged for the state show the effects of different seasons and soil types on soil moisture. In the winter and spring a latitudinal gradient exists with the wetter soils in the southern part of the state. During summer and autumn there is a longitudinal gradient with the wetter soils in the eastern half of the state. The longitudinal gradient is closely associated with the depth of loess deposits.

  3. Wind speed forecasting in the central California wind resource area

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, E.F. [Wind Economics & Technology, Inc., Martinez, CA (United States)

    1997-12-31

    A wind speed forecasting program was implemented in the summer seasons of 1985 - 87 in the Central California Wind Resource Area (WRA). The forecasting program is designed to use either meteorological observations from the WRA and local upper air observations or upper air observations alone to predict the daily average windspeed at two locations. Forecasts are made each morning at 6 AM and are valid for a 24 hour period. Ease of use is a hallmark of the program as the daily forecast can be made using data entered into a programmable HP calculator. The forecasting program was the first step in a process to examine whether the electrical energy output of an entire wind power generation facility or defined subsections of the same facility could be predicted up to 24 hours in advance. Analysis of the results of the summer season program using standard forecast verification techniques show the program has skill over persistence and climatology.

  4. The nighttime F-region climatology during magnetically quiet periods seen from TIMED/GUVI and DMSP

    Science.gov (United States)

    Kil, H.; Paxton, L.; Zhang, Y.; Wolven, B.; Morrison, D.

    2004-12-01

    In this study, we investigate the drivers of the nighttime climatology in the low- and middle-latitude ionosphere during quiet periods using the TIMED/GUVI and DMSP data. The observation results show that the seasonal hemispheric asymmetry in plasma density is primary induced by the summer-to-winter wind circulations while the longitudinal variations of the F-region morphology is produced by the contribution of the zonal winds that depends on the magnetic declination. However, the F-region morphology observed at 625 km from TIMED/GUVI does not precisely conform the morphology observed at 840 km from DMSP. We will discuss the differential neutral wind effect on the F-region morphology depending on the magnetic declination, altitude, and the location of the geomagnetic equator relative to the geographic equator.

  5. How predictable are equatorial Atlantic surface winds?

    Science.gov (United States)

    Richter, Ingo; Doi, Takeshi; Behera, Swadhin

    2017-04-01

    Sensitivity tests with the SINTEX-F general circulation model (GCM) as well as experiments from the Coupled Model Intercomparison Project phase 5 (CMIP5) are used to examine the extent to which sea-surface temperature (SST) anomalies contribute to the variability and predictability of monthly mean surface winds in the equatorial Atlantic. In the SINTEX-F experiments, a control experiment with prescribed observed SST for the period 1982-2014 is modified by inserting climatological values in certain regions, thereby eliminating SST anomalies. When SSTs are set to climatology in the tropical Atlantic only (30S to 30N), surface wind variability over the equatorial Atlantic (5S-5N) decreases by about 40% in April-May-June (AMJ). This suggests that about 60% of surface wind variability is due to either internal atmospheric variability or SSTs anomalies outside the tropical Atlantic. A further experiment with climatological SSTs in the equatorial Pacific indicates that another 10% of variability in AMJ may be due to remote influences from that basin. Experiments from the CMIP5 archive, in which climatological SSTs are prescribed globally, tend to confirm the results from SINTEX-F but show a wide spread. In some models, the equatorial Atlantic surface wind variability decreases by more than 90%, while in others it even increases. Overall, the results suggest that about 50-60% of surface wind variance in AMJ is predictable, while the rest is due to internal atmospheric variability. Other months show significantly lower predictability. The relatively strong internal variability as well as the influence of remote SSTs suggest a limited role for coupled ocean-atmosphere feedbacks in equatorial Atlantic variability.

  6. Boom in Germany; Boom in Deutschland

    Energy Technology Data Exchange (ETDEWEB)

    Janzing, Bernward

    2013-02-15

    In the year 2012, the expansion of the wind energy in Germany has newly gained a rise: 1,008 wind power plants with a total performance of 2,439 megawatt. The average performance of new wind turbines increases further. The average rotor diameter amounts 88.5 metres, while the average hub height amounts 109.8 metres. Above all, the southern Federal States of the Federal Republic of Germany jeopardise on large hub heights: With a hub height of 133.9 metres, Bavaria is in the vanguard of all Federal States followed by Baden-Wuerttemberg with a hub height of 129.9 metres. The wind power plants in Schleswig-Holstein have the lowest average hub height of 81.7 metres. Meanwhile, the repowering occurs in Schleswig-Holstein and Niedersachsen because there are the oldest wind power plants.

  7. A spectral climatology for atmospheric compensation of hyperspectral imagery

    Science.gov (United States)

    Powell, John H.; Resmini, Ronald G.

    2016-05-01

    Most Earth observation hyperspectral imagery (HSI) detection and identification algorithms depend critically upon a robust atmospheric compensation capability to correct for the effects of the atmosphere on the radiance signal. Atmospheric compensation methods typically perform optimally when ancillary ground truth data are available, e.g., high fidelity in situ radiometric observations or atmospheric profile measurements. When ground truth is incomplete or not available, additional assumptions must be made to perform the compensation. Meteorological climatologies are available to provide climatological norms for input into the radiative transfer models; however no such climatologies exist for empirical methods. The success of atmospheric compensation methods such as the empirical line method suggests that remotely sensed HSI scenes contain comprehensive sets of atmospheric state information within the spectral data itself. It is argued that large collections of empirically-derived atmospheric coefficients collected over a range of climatic and atmospheric conditions comprise a resource that can be applied to prospective atmospheric compensation problems. A previous study introduced a new climatological approach to atmospheric compensation in which empirically derived spectral information, rather than sensible atmospheric state variables, is the fundamental datum. The current work expands the approach across an experimental archive of 127 airborne HSI datasets spanning nine physical sites to represent varying climatological conditions. The representative atmospheric compensation coefficients are assembled in a scientific database of spectral observations and modeled data. Improvements to the modeling methods used to standardize the coefficients across varying collection and illumination geometries and the resulting comparisons of adjusted coefficients are presented. The climatological database is analyzed to show that common spectral similarity metrics can be used

  8. Review of Methodologies for Offshore Wind Resource Assessment in European Seas

    DEFF Research Database (Denmark)

    Sempreviva, Anna Maria; Barthelmie, Rebecca Jane; Pryor, Sara

    2008-01-01

    The wind resource offshore is generally larger than at geographically nearby onshore sites, which can offset the higher installation, operation and maintenance costs associated with offshore wind parks. Successful offshore wind energy development relies to some extent on accurate prediction of wind...... promising wind farm sites and (ii) a site specific evaluation of wind climatology and vertical profiles of wind and atmospheric turbulence, in addition to an assessment of historical and possibly future changes due to climate non-stationarity. Phase (i) of the process can involve use of in situ observations......) of the project often still requires in situ observations (which may or may not be supplemented with ground-based remote sensing technologies) and application of tools to provide a climatological context for the resulting measurements. Current methodologies for undertaking these aspects of the resource assessment...

  9. Exploring the calibration of a wind forecast ensemble for energy applications

    Science.gov (United States)

    Heppelmann, Tobias; Ben Bouallegue, Zied; Theis, Susanne

    2015-04-01

    In the German research project EWeLiNE, Deutscher Wetterdienst (DWD) and Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) are collaborating with three German Transmission System Operators (TSO) in order to provide the TSOs with improved probabilistic power forecasts. Probabilistic power forecasts are derived from probabilistic weather forecasts, themselves derived from ensemble prediction systems (EPS). Since the considered raw ensemble wind forecasts suffer from underdispersiveness and bias, calibration methods are developed for the correction of the model bias and the ensemble spread bias. The overall aim is to improve the ensemble forecasts such that the uncertainty of the possible weather deployment is depicted by the ensemble spread from the first forecast hours. Additionally, the ensemble members after calibration should remain physically consistent scenarios. We focus on probabilistic hourly wind forecasts with horizon of 21 h delivered by the convection permitting high-resolution ensemble system COSMO-DE-EPS which has become operational in 2012 at DWD. The ensemble consists of 20 ensemble members driven by four different global models. The model area includes whole Germany and parts of Central Europe with a horizontal resolution of 2.8 km and a vertical resolution of 50 model levels. For verification we use wind mast measurements around 100 m height that corresponds to the hub height of wind energy plants that belong to wind farms within the model area. Calibration of the ensemble forecasts can be performed by different statistical methods applied to the raw ensemble output. Here, we explore local bivariate Ensemble Model Output Statistics at individual sites and quantile regression with different predictors. Applying different methods, we already show an improvement of ensemble wind forecasts from COSMO-DE-EPS for energy applications. In addition, an ensemble copula coupling approach transfers the time-dependencies of the raw

  10. Quantifying the Effect of Lidar Turbulence Error on Wind Power Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Jennifer F.; Clifton, Andrew

    2016-01-01

    Currently, cup anemometers on meteorological towers are used to measure wind speeds and turbulence intensity to make decisions about wind turbine class and site suitability; however, as modern turbine hub heights increase and wind energy expands to complex and remote sites, it becomes more difficult and costly to install meteorological towers at potential sites. As a result, remote-sensing devices (e.g., lidars) are now commonly used by wind farm managers and researchers to estimate the flow field at heights spanned by a turbine. Although lidars can accurately estimate mean wind speeds and wind directions, there is still a large amount of uncertainty surrounding the measurement of turbulence using these devices. Errors in lidar turbulence estimates are caused by a variety of factors, including instrument noise, volume averaging, and variance contamination, in which the magnitude of these factors is highly dependent on measurement height and atmospheric stability. As turbulence has a large impact on wind power production, errors in turbulence measurements will translate into errors in wind power prediction. The impact of using lidars rather than cup anemometers for wind power prediction must be understood if lidars are to be considered a viable alternative to cup anemometers.In this poster, the sensitivity of power prediction error to typical lidar turbulence measurement errors is assessed. Turbulence estimates from a vertically profiling WINDCUBE v2 lidar are compared to high-resolution sonic anemometer measurements at field sites in Oklahoma and Colorado to determine the degree of lidar turbulence error that can be expected under different atmospheric conditions. These errors are then incorporated into a power prediction model to estimate the sensitivity of power prediction error to turbulence measurement error. Power prediction models, including the standard binning method and a random forest method, were developed using data from the aeroelastic simulator FAST

  11. Eight Year Climatologies from Observational (AIRS) and Model (MERRA) Data

    Science.gov (United States)

    Hearty, Thomas; Savtchenko, Andrey; Won, Young-In; Theobalk, Mike; Vollmer, Bruce; Manning, Evan; Smith, Peter; Ostrenga, Dana; Leptoukh, Greg

    2010-01-01

    We examine climatologies derived from eight years of temperature, water vapor, cloud, and trace gas observations made by the Atmospheric Infrared Sounder (AIRS) instrument flying on the Aqua satellite and compare them to similar climatologies constructed with data from a global assimilation model, the Modern Era Retrospective-Analysis for Research and Applications (MERRA). We use the AIRS climatologies to examine anomalies and trends in the AIRS data record. Since sampling can be an issue for infrared satellites in low earth orbit, we also use the MERRA data to examine the AIRS sampling biases. By sampling the MERRA data at the AIRS space-time locations both with and without the AIRS quality control we estimate the sampling bias of the AIRS climatology and the atmospheric conditions where AIRS has a lower sampling rate. While the AIRS temperature and water vapor sampling biases are small at low latitudes, they can be more than a few degrees in temperature or 10 percent in water vapor at higher latitudes. The largest sampling biases are over desert. The AIRS and MERRA data are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The AIRS climatologies we used are available for analysis with the GIOVANNI data exploration tool. (see, http://disc.gsfc.nasa.gov).

  12. Wind resource assessment: A three year experience

    Energy Technology Data Exchange (ETDEWEB)

    Al-Abbadi, N.M.; Alawaji, S.H.; Eugenio, N.N. [Energy Research Institute (ERI), Riyadh (Saudi Arabia)

    1997-12-31

    This paper presents the results of data collected from three different sites located in the central, northern and eastern region of Saudi Arabia. Each site is geographically and climatologically different from the others. Statistical moments and frequency distributions were generated for the wind speed and direction parameters to analyse the wind energy characteristics and its availability. The results of these statistical operations present the wind power and energy density estimates of the three sites. The data analysis presented a prospect of wind energy conversion and utilization. The annual extractable energy density is 488, 890, 599 kWh/m{sup 2} for the central, northern and eastern sites respectively. Also, the paper demonstrates the lessons learned from operating wind assessment stations installed in remote areas having different environmental characteristics.

  13. A methodology for the prediction of offshore wind energy resources

    Energy Technology Data Exchange (ETDEWEB)

    Watson, S.J.; Watson, G.M. [Rutherford Appleton Lab., Oxfordshire (United Kingdom); Holt, R.J. [Univ. of East Anglia, Climatic Research Unit, Norwich (United Kingdom)] Barthelmie, R.J. [Risoe National Lab., Dept. of Wind Energy and Atmospheric Physics, Roskilde (Denmark); Zuylen, E.J. van [Ecofys Energy and Environment, Utrecht (Netherlands)] Cleijne, J.W. [Kema Sustainable, Arnhem (Netherlands)

    1999-03-01

    There are increasing constraints on the development of wind power on land. Recently, there has been a move to develop wind power offshore, though the amount of measured wind speed data at potential offshore wind farm sites is sparse. We present a novel methodology for the prediction of offshore wind power resources which is being applied to European Union waters. The first stage is to calculate the geostrophic wind from long-term pressure fields over the sea area of interest. Secondly, the geostrophic wind is transformed to the sea level using WA{sup s}P, taking account of near shore topography. Finally, these values are corrected for land/sea climatology (stability) effects using an analytical Coastal discontinuity Model (CDM). These values are further refined using high resolution offshore data at selected sites. The final values are validated against existing offshore datasets. Preliminary results are presented of the geostrophic wind speed validation in European Union waters. (au)

  14. Climatology of vTEC at midnight over mid-latitude regions using PCA

    Science.gov (United States)

    Natali, M. Paula; Meza, Amalia

    2017-04-01

    At night the content of the electron density at mid-latitude is mainly controlled by loss processes, recombination and electron movement, which are related by the continuity equation. The vertical wind plays an important role in these processes. Global vertical Total Electron Content (vTEC) maps produced by the International Global Navigation Satellite System (GNSS) Service, the Horizontal Wind Model 2007 (HWM07) and the International Reference Ionosphere (IRI) 2012 model are used to describe the climatology at midnight over mid-latitude regions during 2000-2002. In particular, four regions were selected. They are approximately centered in zero magnetic declination, two in the northern hemisphere and two in southern hemisphere. They are located near and far from geomagnetic poles respectively. Principal Components Analysis (PCA) technique highlights the spatial-temporal variations to the overall vTEC variability which can be well represented by an orthogonal base. Indeed, we show for the four selected regions the contributions of the first three modes account for more than 95% of its variability. PCA results show that vTEC variability respond to vertical wind variation with decreasing values of about 10% -15% with the action of a vertical wind lasting for two hours. The Mid-latitude Summer Night Anomaly (MSNA), which is directly related with vertical wind, is present in regions far from geomagnetic poles. A remnant effect of the winter anomaly is also observed, in regions near geomagnetic poles. A longitudinal variation for mid-latitude ionospheric vTEC with maximum values in equinoxes, associated with negative and positive magnetic declination in all regions is observed. For the IRI model, PCA results, are quite similar but the mean values are lower than the obtained with the Global vTEC Maps. These data show the MSNA but not the remnant of the winter anomaly. In all regions the longitudinal variation is present with the same seasonal variation as Global vTEC Maps.

  15. Five-day back trajectory climatology for Rukomechi (Zambezi valley, Zimbabwe)

    Science.gov (United States)

    Nyanganyura, D.; Makarau, A.; Milford, J. R.; Mathuthu, M.; Helas, G.; Meixner, F. X.

    2003-04-01

    A five-year (1994-1999) back trajectory climatology has been established for Rukomechi Research Station/Zimbabwe (Zambezi Valley, 16^o 09' S, 29^o 26'E). Mixed layer air trajectories passing over Rukomechi are described in terms of directions of origin, wind speed, and inter- and intra annual periods of predominant flow. Trajectories show four possible source regions of air mass transport to Rukomechi: (1) northern Madagascar and Mozambique (with high winds during October/ November and low winds during December/January), (2) the Indian ocean south of Madagascar (with high and low winds during March and August/September, respectively), (3) the southern Atlantic and the tip of South Africa regions (with high winds during the middle of austral winter (June/July)), and (4) Zambia and Angola (bringing in mid-wet season air masses, which might carry the influence of the ITCZ). We also observed recirculating air masses which seem not to portray any season characteristics and which change year-by-year. The slow component of corridor (2) shows prevailing tendency, it is the main contributor of airflow to Rukomechi and it is dominant in the dry period (October to December). The year-to-year temporal variations show that 1997 was an abnormal year for the airflow over the research site. This has to be studied together with the variation in the meteorological parameters like rainfall during this period to find the influence of northern Zimbabwe air masses flows on the regional weather patterns. The importance of the presented classification is to narrow potential source regions of trace constituents and their most likely times of influence at Rukomechi througout the year on a monthly basis.

  16. Understanding the Climatology of Thermodynamic Signatures and their Role in Modification of Extreme Precipitation around Artificial Reservoirs

    Science.gov (United States)

    Degu, A. M.; Hossain, F.

    2010-12-01

    Very little is known about how dams and reservoirs modify rainfall and flood frequency in their vicinity. This is because conventional dam design and reservoir planning over the last century have been “one-way,” without acknowledging the possible feedback mechanisms on precipitation recycling due to local evaporation and systematic change in land use and land cover. In this study, using the North American Regional Reanalysis (NARR) database, the climatology of important thermodynamic signatures, such as CAPE (Convective Available Potential Energy), Convective Inhibition, Temperature, Latent Heat, Humidity, Precipitation and Wind are analyzed as a function of proximity to large artificial reservoirs in the United States. The analysis is cast in the context of the chronology of extreme precipitation trends around dams for the pre-dam and post-dam period. To understand how storms may have been intensified by reservoirs, the climatology was analyzed for a set of about 100 large dams for three specific scenarios: 1) right over the reservoir 2) right over land adjacent to the reservoir and 3) over land far away from the reservoir by at least 100 km. Precipitation records from the Global Historical Climate Network (GHCN) were used to correlate the temporal and spatial trends in extreme precipitation to the climatology of the thermodynamic signatures. Several hypotheses on the physical mechanism of storm intensification are proposed and tested using the analysis presented herein. Location of large dams with their climatic classification

  17. Fore- and nowcasting of the electricity production of wind turbines in complex terrain; Fore- und Nowcasting der Stromproduktion von Windenergieanlagen in komplexem Gelaende

    Energy Technology Data Exchange (ETDEWEB)

    Dierer, S.; Remund, J.; Schaffner, B. [Genossenschaft METEOTEST, Bern (Switzerland); Hug, Ch.; Stauch, V. [Federal Office of Meteorology and Climatology MeteoSwiss, Berne (Switzerland)

    2009-09-15

    In the research project 'Fore- and nowcasting of the electricity production of wind turbines in complex terrain' several forecast methods were developed and tested in a prototype. The forecasts were analysed for two temporal horizons: Short term forecasts for the next day as well as shortest term forecasts for intra-day trade. Hourly values of wind speed and power output were forecast. The following methods were developed and analysed: (i) Direct Model Output: Wind speed forecasts were directly adopted from MeteoSwiss's operational numerical weather model COSMO. Power output was derived using the theoretical power curve of each wind turbine. (ii) WindSim: WindSim is a high resolution model for simulating wind fields over complex terrain. The COSMO model's wind speed forecasts were transferred to hub height at the turbine sites based on wind fields calculated by WindSim. Power output was derived using the theoretical power curve of each wind turbine. (iii) Model Output Statistics: Based on historical data, linear relations between the forecast parameters and measured data (wind speed and power output) was determined for each site individually. Based on these, current COSMO forecast were transferred to wind speed and power output forecasts. (iv) Kalman Filter: Based on the local wind measurements of the last 24 hours, forecast errors were continuously updated and the COSMO forecasts were accordingly corrected. Power forecasts were calculated based on the empirical relation between measured wind speeds and power output at each site. These methods were developed successfully for short and shortest term forecasts. Despite the very complex terrain of Switzerland, the accuracy of the results is mostly in the range of or better than international reference values. On one hand, the developed methods display similar performances; on the other hand, they are based on different input data. This allows a certain flexibility for the development of operational

  18. Climatology of the winter Red Sea Trough

    Science.gov (United States)

    Awad, Adel M.; Almazroui, Mansour

    2016-12-01

    In this study, a new and objective method for detecting the Red Sea Trough (RST) was developed using mean sea level pressure (SLP) data from NCEP/NCAR reanalysis dataset from the winters of 1956 to 2015 to identify the Sudan Low and its trough. Approximately 96% of the winter RSTs were generated near two main sources, South Sudan and southeastern Sudan, and approximately 85% of these troughs were in four of the most outer areas surrounding the northern Red Sea. Moreover, from west to east of the Red Sea, the RST was affected by the relationships between the Siberian High and Azores High. The RST was oriented to the west when the strength of the Siberian High increased and to the east when the strength of the Azores High increased. Furthermore, the synoptic features of the upper level of the RST emphasize the impacts of subtropical anticyclones at 850 hPa on the orientation of the RST, the impacts of the northern cyclone trough and the maximum wind at a pressure level of 250 hPa. The average static stability between 1000 hPa and 500 hPa demonstrated that the RST followed the northern areas of low static stability. The results from previous studies were confirmed by a detailed case study of the RST that extended to its central outermost area. The results of a detailed case study of the short RST indicated that the trough becomes shorter with increasing static stability and that the Azores and Siberian high-pressure systems influence the northern region of the trough while the maximum upper wind shifts south of the climate position.

  19. The use of normalized climatological anomalies to rank synoptic-scale events and their relation to Weather Types

    Science.gov (United States)

    Ramos, A. M.; Lorenzo, M. N.; Gimeno, L.; Nieto, R.; Añel, J. A.

    2009-09-01

    Several methods have been developed to rank meteorological events in terms of severity, social impact or economic impacts. These classifications are not always objective since they depend of several factors, for instance, the observation network is biased towards the densely populated urban areas against rural or oceanic areas. It is also very important to note that not all rare synoptic-scale meteorological events attract significant media attention. In this work we use a comprehensive method of classifying synoptic-scale events adapted from Hart and Grumm, 2001, to the European region (30N-60N, 30W-15E). The main motivation behind this method is that the more unusual the event (a cold outbreak, a heat wave, or a flood), for a given region, the higher ranked it must be. To do so, we use four basic meteorological variables (Height, Temperature, Wind and Specific Humidity) from NCEP reanalysis dataset over the range of 1000hPa to 200hPa at a daily basis from 1948 to 2004. The climatology used embraces the 1961-1990 period. For each variable, the analysis of raking climatological anomalies was computed taking into account the daily normalized departure from climatology at different levels. For each day (from 1948 to 2004) we have four anomaly measures, one for each variable, and another, a combined where the anomaly (total anomaly) is the average of the anomaly of the four variables. Results will be analyzed on a monthly, seasonal and annual basis. Seasonal trends and variability will also be shown. In addition, and given the extent of the database, the expected return periods associated with the anomalies are revealed. Moreover, we also use an automated version of the Lamb weather type (WT) classification scheme (Jones et al, 1993) adapted for the Galicia area (Northwestern corner of the Iberian Peninsula) by Lorenzo et al (2008) in order to compute the daily local circulation regimes in this area. By combining the corresponding daily WT with the five anomaly

  20. Wind Power

    OpenAIRE

    Makhalas, Kharsan Al; Alsehlli, Faisal

    2015-01-01

    This Bachelor thesis has been written at the Blekinge Institute of Technology. This thesis concentrates on the wind power and their components, also the large wind farm is studied. The electrical power is generated by using the power in wind to drive a wind turbine to produce mechanical power. This mechanical power can be converted into electrical power by using electrical induction generators. There are two types of the wind turbines, the horizontal axis and vertical axis wind turbine, where...

  1. Wind Sensor

    OpenAIRE

    Li, Jiaoyang; Ni, Jiqin

    2014-01-01

    Wind measurement is needed in many practical and scientific research situations. Some specific applications require to precisely measuring both wind direction and wind speed at the same time. Current commercial sensors for wind direction and wind speed measurement usually use ultrasonic technology and the sensors are very expensive (> $1500). In addition, the sensors are large in dimension and cannot measure airflow patterns in high spatial resolution. Therefore new and low cost wind speed an...

  2. Spatial models for probabilistic prediction of wind power with application to annual-average and high temporal resolution data

    DEFF Research Database (Denmark)

    Lenzi, Amanda; Pinson, Pierre; Clemmensen, Line Katrine Harder;

    2016-01-01

    Producing accurate spatial predictions for wind power generation together with a quantification of uncertainties is required to plan and design optimal networks of wind farms. Toward this aim, we propose spatial models for predicting wind power generation at two different time scales: for annual...... that our method makes it possible to obtain fast and accurate predictions from posterior marginals for wind power generation. The proposed method is applicable in scientific areas as diverse as climatology, environmental sciences, earth sciences and epidemiology....

  3. A Novel Sampling Method for Satellite-Based Offshore Wind Resource Estimation

    DEFF Research Database (Denmark)

    Badger, Merete; Badger, Jake; Hasager, Charlotte Bay

    Synthetic aperture radar (SAR) measurements from satellites can be used to estimate the spatial wind speed variation offshore in great detail. The radar senses cm-scale roughness at the sea surface which can be translated to wind speed at the height 10 m using an empirical geophysical model......-based wind climatology have improved gradually as more data were collected. The satellite scenes have been treated as random samples and weighted equally in our previous analyses. Here we introduce a novel sampling strategy based on the wind class methodology that is normally applied in numerical modeling...... climatologically representative large-scale meteorological conditions for the region of interest. The wind classes are used to make the most representative selection of satellite images from the ENVISAT image catalogue. A minimum of one satellite image is chosen per wind class. The frequency of occurrence of each...

  4. GLOBE backscatter - Climatologies and mission results. [Global Backscatter Experiment

    Science.gov (United States)

    Menzies, Robert T.; Post, Madison J.

    1991-01-01

    The Global Backscatter Experiment (GLOBE) goals require intensive study of the global climatology of atmospheric aerosol backscatter at IR wavelengths. Airborne and ground-based lidars have been developed to measure atmospheric backscatter profiles at CO2 laser wavelengths. Descriptions of the calibration techniques and selected measurement results are presented.

  5. Climatology and Landfall of Tropical Cyclones in the South- West ...

    African Journals Online (AJOL)

    Mozambique; 2University of Gothenburg, Department of Earth Sciences, Oceanography, Box 460, SE-405. 30 Gothenburg ... La Reunion – Regional Specialised Meteorological Centre. During the ..... higher mean genesis temperature than climatology. SSTs. ..... Australian Meteorological Society, 16, 135-137. Klinman M.G ...

  6. Completion of the Edward Air Force Base Statistical Guidance Wind Tool

    Science.gov (United States)

    Dreher, Joseph G.

    2008-01-01

    The goal of this task was to develop a GUI using EAFB wind tower data similar to the KSC SLF peak wind tool that is already in operations at SMG. In 2004, MSFC personnel began work to replicate the KSC SLF tool using several wind towers at EAFB. They completed the analysis and QC of the data, but due to higher priority work did not start development of the GUI. MSFC personnel calculated wind climatologies and probabilities of 10-minute peak wind occurrence based on the 2-minute average wind speed for several EAFB wind towers. Once the data were QC'ed and analyzed the climatologies were calculated following the methodology outlined in Lambert (2003). The climatologies were calculated for each tower and month, and then were stratified by hour, direction (10" sectors), and direction (45" sectors)/hour. For all climatologies, MSFC calculated the mean, standard deviation and observation counts of the Zminute average and 10-minute peak wind speeds. MSFC personnel also calculated empirical and modeled probabilities of meeting or exceeding specific 10- minute peak wind speeds using PDFs. The empirical PDFs were asymmetrical and bounded on the left by the 2- minute average wind speed. They calculated the parametric PDFs by fitting the GEV distribution to the empirical distributions. Parametric PDFs were calculated in order to smooth and interpolate over variations in the observed values due to possible under-sampling of certain peak winds and to estimate probabilities associated with average winds outside the observed range. MSFC calculated the individual probabilities of meeting or exceeding specific 10- minute peak wind speeds by integrating the area under each curve. The probabilities assist SMG forecasters in assessing the shuttle FR for various Zminute average wind speeds. The A M ' obtained the processed EAFB data from Dr. Lee Bums of MSFC and reformatted them for input to Excel PivotTables, which allow users to display different values with point

  7. Economy of wind power plants; In Denmark; Vindmoellers oekonomi

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Per (EMD International, Aalborg (Denmark)); Lemming, J.; Morthorst, P.E.; Clausen, N.E.; Lawetz, H. (Risoe DTU, Roskilde (Denmark)); Lindboe, H.H.; James-Smith, E.; Bang, N.C. (EA analyse, Copenhagen (Denmark)); Stroem, S. (Vindmoelleindustrien, Frederiksberg (Denmark)); Larsen, J. (Danmarks Vindmoelleforening, AArhus (Denmark))

    2010-02-15

    This report provides a status on costs of wind energy projects at the end of 2009 including O and M costs based on statistics gathered from more than 250 operating turbines in Denmark with a capacity of 600 kW and up. The figures are applicable for Danish conditions; hence the findings of the project cannot be directly applied in other countries. The report contains data for both on- and offshore projects. The main findings regarding actual costs as well as expected future costs are available in English in Appendix 2. The index regulated price of turbines has increased by approx. 30% per MW over the past six years. It is, however, important to consider the change in size of a typical turbine in the same period. Larger rotors per MW as well as increased hub heights have increased production levels per installed MW. This has acted as a counterweight to increasing prices per installed MW. When costs per MWh are compared over the same period there has been no increase in production costs. However, for sites that cannot benefit from the larger turbines e.g. due to environmental impact reasons, the 30% cost increase is real. In the report, the results of a detailed cost calculator are presented, showing the effect of changes in specific power and hub height. O and M costs have been investigated in detail based on a large sample of data from turbines with a capacity of 600 kW and up. Some of these have been in operation for up to 14 years. It has been discovered that many turbines have had gearbox problems after 7 to 10 years of operation, causing significant additional costs over and above the normal operating costs. The four main cost components of O and M costs for wind turbines are repair, insurance, service agreement and administration/land rent. Each component represents around 25% of the total O and M costs. Expected lifetime average costs are round 1.2 Euro c/kWh. The expected cost of wind electricity has been calculated. This is not only determined by the local

  8. EU-NORSEWIND - Delivering Offshore Wind Speed Data

    DEFF Research Database (Denmark)

    Oldroyd, Andy; Hasager, Charlotte Bay; Stickland, M.T.

    Offshore wind is the major growth area in the wind industry sector today, with a host of large projects being announced and innovative approaches being proposed. However, with all this investment and innovation there remains a key, fundamental missing element - a thorough understanding...... of the offshore wind climatology and likely wind resource. As the wind industry starts to look in detail at the wind regime offshore, the need for more physical data becomes apparent. As well as the normal AEP requirements for project finance, baseline data is required in order to better understand the local...... conditions with respect to shear and hence loading implications, and of equal concern directionality which can feed into important research areas such as offshore wake propagation. Indeed, a good baseline understanding of the wind flow regime is essential in being able to determine the accumulative impact...

  9. Modelling studies of wind field on urban environment

    Directory of Open Access Journals (Sweden)

    K. Radics

    2002-11-01

    Full Text Available Increasing load of air pollution in urban environment emphasises the need for detailed evaluation of wind characteristics that significantly affect the air quality of urban areas, especially, in large agglomerations. This paper includes analysis of urban wind climatology and estimation of wind profiles based on measurements of the new urban climate station located at the Eötvös University, observations of the meteorological station network of the Budapest agglomeration area, and multi-level wind measurements near Hegyhátsál. Furthermore, wind field modelling (using the WAsP linear spectral wind flow model is presented over selected representative complex areas that demonstrates strong dependence between wind, height, topography, and roughness.

  10. Conditional prediction intervals of wind power generation

    DEFF Research Database (Denmark)

    Pinson, Pierre; Kariniotakis, Georges

    2010-01-01

    A generic method for the providing of prediction intervals of wind power generation is described. Prediction intervals complement the more common wind power point forecasts, by giving a range of potential outcomes for a given probability, their so-called nominal coverage rate. Ideally they inform...... on the characteristics of prediction errors for providing conditional interval forecasts. By simultaneously generating prediction intervals with various nominal coverage rates, one obtains full predictive distributions of wind generation. Adapted resampling is applied here to the case of an onshore Danish wind farm......, for which three point forecasting methods are considered as input. The probabilistic forecasts generated are evaluated based on their reliability and sharpness, while compared to forecasts based on quantile regression and the climatology benchmark. The operational application of adapted resampling...

  11. A climatology of airborne dust for the Red River Valley of North Dakota

    Science.gov (United States)

    Godon, Nancy A.; Todhunter, Paul E.

    The Red River Valley of North Dakota has been identified as one of the highest potential dust production regions in the United States. This paper provides a climatological summary of the airborne dust environment in the region using historical meteorological data for Fargo, North Dakota. Data for the period 1948-1994 were extracted for all 3-hourly weather observations which recorded an obstruction to vision due to dust, blowing dust or dust storms. Data were compiled on the year, month, day and hour of each observation, as well as the horizontal visibility, wind speed, wind direction, and other present weather occurring at the time of each event. Airborne dust events in the Red River Valley of the North normally involve local entrainment of dust, and show a strong peak in the frequency of occurrence during the afternoon and spring seasons, although a secondary winter peak is also present. Dust events have decreased in frequency over the study period, apparently in response to improved farm management practices. Most events fall into two basic categories: winter events generated by passing cold fronts or strong regional pressure gradients, and often accompanied by blowing snow and light snow showers, and spring events triggered by the passage of cyclones and fronts, and normally not accompanied by other prevailing weather at the time of the observation. Results are discussed in relation to the unique soil, meteorological and surface cover conditions of the Red River Valley of North Dakota.

  12. On the Integration of Wind and Solar Energy to Provide a Total Energy Supply in the U.S

    Science.gov (United States)

    Liebig, E. C.; Rhoades, A.; Sloggy, M.; Mills, D.; Archer, C. L.

    2009-12-01

    This study examines the feasibility of using renewable energy - mostly wind and solar radiation - as the primary sources of energy in the U.S., under the assumption that a nationwide electric transmission grid is in place. Previous studies have shown that solar output from California and Texas using energy storage is well correlated with the state energy load on an hour by hour basis throughout the year and with the US national load on a monthly basis. Other studies have shown that solar or wind alone can power the present US grid on average. This study explores scenarios for use of wind and solar energy together at the national scale on an hour by hour basis to determine if such a combination is a better match to national seasonal load scenarios than either of the two alone on an hour-by-hour basis. Actual hour by hour national load data from a particular year will be used as a basis, with some scenarios incorporating vehicle sector electrification and building heating and cooling using electric heat pumps. Hydro and geothermal generation can provide additional controllable output, when needed, to fulfill the hourly electricity and/or energy needs. Hourly wind speed data were calculated at the hub height of 80 m above the ground for the year 2006 at over 150 windy locations in the continental US using an extrapolation technique based on 10-m wind speed measurements and vertical sounding profiles. Using a 1.5 MW wind turbine as benchmark, the hourly wind power production nationwide was determined at all locations. Similarly, the hourly output from solar plants, with and without thermal storage, was calculated based on Ausra’s model assuming that the solar production would occur in the Southwest, the area with the greatest solar radiation density in the U.S. Hourly electricity demand for the year 2006 was obtained nationwide from a variety of sources, including the Federal Energy Regulation Commission. Hourly residential heating and cooking, industrial heat

  13. Wind Structure and Wind Loading

    DEFF Research Database (Denmark)

    Brorsen, Michael

    The purpose of this note is to provide a short description of wind, i.e. of the flow in the atmosphere of the Earth and the loading caused by wind on structures. The description comprises: causes to the generation of windhe interaction between wind and the surface of the Earthhe stochastic nature...... of windhe interaction between wind and structures, where it is shown that wind loading depends strongly on this interaction...

  14. Improved estimates of the European winter wind storm climate and the risk of reinsurance loss

    Science.gov (United States)

    Della-Marta, P. M.; Liniger, M. A.; Appenzeller, C.; Bresch, D. N.; Koellner-Heck, P.; Muccione, V.

    2009-04-01

    Current estimates of the European wind storm climate and their associated losses are often hampered by either relatively short, coarse resolution or inhomogeneous datasets. This study estimates the European wind storm climate using dynamical seasonal-to-decadal (s2d) climate forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF). The current s2d models' have limited predictive skill of European storminess, making the ensemble forecasts ergodic samples on which to build pseudo climates of 310 to 396 years in length. Extended winter (ONDJFMA) wind storm climatologies are created using a scalar extreme wind index considering only data above a high threshold. The method identifes between 2331 and 2471 wind storms using s2d data and 380 wind storms in ERA-40. Classical extreme value analysis (EVA) techniques are used to determine the wind storm climatologies. We suggest that the ERA-40 climatology, by virtue of its length, limiting form, and the fitting method, overestimates the return period (RP) of wind storms with RPs between 10-300 years and underestimates the return period of wind storms with RPs greater than 300 years. A 50 year event in ERA-40 is approximately a 33 year event using s2d. The largest influence on ERA-40 RP uncertainties is the sampling variability associated with only 45 seasons of storms. The climatologies are linked to the Swiss Reinsurance Company (Swiss Re) European wind storm loss model. New estimates of the risk of loss are compared with those from historical and stochastically generated wind storm fields used by Swiss Re. The resulting loss-frequency relationship matches well with the two independently modelled estimates and clearly demonstrates the added value by using alternative data and methods, as proposed in this study, to estimate the RP of high RP losses.

  15. Comparison of SAR-derived wind speed with the wind energy simulation toolkit (WEST)

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, P.; Lafrance, G.; Bernier, M. [Quebec Univ., Quebec City, PQ (Canada). Institut National de la Recherche Scientifique-Eau, Terre et Environnement; Glazer, A.; Benoit, R.; Yu, W. [Environment Canada, Gatineau, PQ (Canada)

    2005-07-01

    Wind power increases with air density, wind speed, and the surface area of wind turbine blades. Wind speed increases with altitude and topographic effects such as lower surface roughness, and high pressure gradient forcing. A comparative evaluation of a mesoscale compressible community numerical model (MC2) and synthetic aperture radar satellites (SAR) was presented. Wind speed predictions were presented, and details of both models were reviewed. Features of the MC2 included non hydrostatic Euler equations; a 3-D Lagrangian advection; full physical processes; resolution to a few km; self-nesting capabilities; topography adjustable at start-up; and open sourcing. Inputs included climatological fields; geophysical fields; initial and boundary atmospheric conditions; and dynamical and physical simulation settings. Outputs included wind speed vectors, pressure, temperature and humidity. Wind measurements from SAR satellites is conducted by observing wind friction in water. Radar signals are related to sea waves by Bragg resonant scattering. A geophysical model function establishes a semi-empirical relationship between the radar signal and wind vector. Several sources of wind direction inputs for SAR included scatterometer data; FFT of wind streaks on SAR images; local gradient filters on SAR images; NWP data; offshore coastal buoys and masts data. It was noted that with SAR, wind patterns were well represented and wind accuracy was improved. Micro-scale resolution is available and further improvements are expected with the launch of new satellites. Results of various studies comparing the use of MC2 and SAR in coastal waters were presented. It was concluded that wind features are well resolved by SAR and MC2 methods. A fusion of both methods was recommended to improve coastal and offshore wind assessments. refs., tabs., figs.

  16. Coastal Ohio Wind Project for Reduced Barriers to Deployment of Offshore Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Gorsevski, Peter; Afjeh, Abdollah; Jamali, Mohsin; Carroll, Michael

    2014-04-09

    mitigate adverse effects of ice formation on wind turbine structures. Firstly, a Zephir LiDAR system was acquired and installed at Woodlands School in Huron, Ohio, which is located near Lake Erie. Wind resource data were obtained at ten measurement heights, 200m, 150m, 100m, 80m, 60m, 40m, 38m, 30m, 20m, and 10m. The Woodlands School’s wind turbine anemometer also measured the wind speed at the hub height. These data were collected for approximately one year. The hub anemometer data correlated well with the LiDAR wind speed measurements at the same height. The data also showed that on several days different power levels were recorded by the turbine at the same wind speed as indicated by the hub anemometer. The corresponding LiDAR data showed that this difference can be attributed to variability in the wind over the turbine rotor swept area, which the hub anemometer could not detect. The observation suggests that single point hub wind velocity measurements are inadequate to accurately estimate the power generated by a turbine at all times since the hub wind speed is not a good indicator of the wind speed over the turbine rotor swept area when winds are changing rapidly. To assess the effectiveness of ice coatings to mitigate the impact of ice on turbine structures, a closed-loop icing research tunnel (IRT) was designed and constructed. By controlling the temperature, air speed, water content and liquid droplet size, the tunnel enabled consistent and repeatable ice accretion under a variety of conditions with temperatures between approximately 0°C and -20°C and wind speeds up to 40 miles per hour in the tunnel’s test section. The tunnel’s cooling unit maintained the tunnel temperature within ±0.2°C. The coatings evaluated in the study were Boyd Coatings Research Company’s CRC6040R3, MicroPhase Coatings Inc.’s PhaseBreak TP, ESL and Flex coatings. Similar overall performance was observed in all coatings tested in that water droplets form on the test articles

  17. RADAR CLIMATOLOGY OF HAIL IN THE APUSENI MOUNTAINS

    Directory of Open Access Journals (Sweden)

    N. MAIER

    2011-03-01

    Full Text Available Radar Climatology of hail in the Apuseni Mountains A newmethod for the assessment of large areas with frequent occurrence of hail in a finespatial resolution and its application for the Apuseni Mountains and their adjacentareas is presented. Due to the fine tempo-spatial resolution of the radar detection,the creation of radar climatology of the areas where the hail production conditionsare determined is imposed. With the help of two Doppler radars at Oradea andBobohalma, the area of interest is examined and spatial maps of the relativefrequency of hail contained in the clouds are made. Composite maps are made (bysuperimposing the two Doppler radar images from Oradea and Bobohalma of theareas in which clouds with hail of different sizes occur.

  18. Climatology of surface ultraviolet-radiation in Valparaiso, Chile

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, Raul R. [Universidad Tecnica Federico Santa Maria, Ave. Espana 1680, Valparaiso (Chile) and Escuela Superior Politecnica del Litoral, Km. 30, 5 Via Perimetral, Guayaquil (Ecuador)]. E-mail: raul.cordero@usm.cl; Roth, Pedro [Universidad Tecnica Federico Santa Maria, Ave. Espana 1680, Valparaiso (Chile); Georgiev, Aleksandar [Technical University of Sofia, 4023 Plovdiv (Bulgaria); Silva, Luis da [Universidad Tecnica Federico Santa Maria, Ave. Espana 1680, Valparaiso (Chile)

    2005-11-15

    Despite the lack of long-term records, it is possible to describe many of the short term characteristics, dependencies and climatology of surface UV irradiance. This paper describes the climatology of on ground UV irradiance at Valparaiso (33.05 deg. S, 71.63 deg. W, sea level), Chile. The dependence of UV-B irradiance on ozone and on other climate variables is discussed with reference to our observations conducted during the last four years. Special attention was paid to detect 'ozone events' by surface UV irradiance measurements. By analyzing time series of the UV-B/UV-A ratio, we suppressed the cloud variability effect and detected events that implied ozone column changes of about 15%. According to our measurements, during the last four years, the ozone column over Valparaiso was not affected negatively by the Antarctic ozone hole phenomenon.

  19. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset

    Science.gov (United States)

    Huffman, George J.; Adler, Robert F.; Arkin, Philip; Chang, Alfred; Ferraro, Ralph; Gruber, Arnold; Janowiak, John; McNab, Alan; Rudolf, Bruno; Schneider, Udo

    1997-01-01

    The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit -satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 deg x 2.5 deg latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

  20. Clear sky atmosphere at cm-wavelengths from climatology data

    CERN Document Server

    Lew, Bartosz

    2015-01-01

    We utilise ground-based, balloon-born and satellite climatology data to reconstruct site and season-dependent vertical profiles of precipitable water vapour (PWV). We use these profiles to numerically solve radiative transfer through the atmosphere, and derive atmospheric brightness temperature ($T_{\\rm atm}$) and optical depth ($\\tau$) at the centimetre wavelengths. We validate the reconstruction by comparing the model column PWV, with photometric measurements of PWV, performed in the clear sky conditions towards the Sun. Based on the measurements, we devise a selection criteria to filter the climatology data to match the PWV levels to the expectations of the clear sky conditions. We apply the reconstruction to the location of the Polish 32-metre radio telescope, and characterise $T_{\\rm atm}$ and $\\tau$ year-round, at selected frequencies. We also derive the zenith distance dependence for these parameters, and discuss shortcomings of using planar, single-layer, and optically thin atmospheric model approxima...

  1. Evaluations of SST Climatologies in the Tropical Pacific Ocean

    Science.gov (United States)

    2009-02-27

    boundaries Casey and Cornillon, 1999]. An observation-based clima - r 1 -ru 1 r.u- • . .r e...along with SSTs from AVHRR satellite retrievals. The NOAA SST product was built from two intermediate climatologies: a 2° SST clima - tology developed...2D-Var data sets, depending on the period considered. Thus, ECMWF clima - tologies examined here are the analyses of SST observations prescribed as

  2. Ozonesonde climatology between 1995 and 2009: description, evaluation and applications

    Directory of Open Access Journals (Sweden)

    S. Tilmes

    2011-10-01

    Full Text Available An ozone climatology based on ozone soundings for the last 15 years has been constructed for model evaluation and comparisons to other observations. Vertical ozone profiles for 41 stations around the globe have been compiled and averaged for the years 1980–1994 and 1995–2009. The climatology provides information about the median and the width of the ozone probability distribution function, as well as interannual variability of ozone between 1995 and 2009, in pressure and tropopause-referenced altitudes. In addition to single stations, regional aggregates are presented, combining stations with similar ozone characteristics. The Hellinger distance is introduced as a new diagnostic to compare the variability of ozone distributions within each region and used for model evaluation purposes. This measure compares not only the mean, but also the shape of distributions. The representativeness of regional aggregates is discussed using independent observations from surface stations and MOZAIC aircraft data. Ozone from all of these data sets show an excellent agreement within the range of the interannual variability, especially if a sufficient number of measurements are available, as is the case for West Europe. Within the climatology, a significant longitudinal variability of ozone in the troposphere and lower stratosphere in the northern mid- and high latitudes is found. The climatology is used to evaluate results from two model intercomparison activities, HTAP for the troposphere and CCMVal2 for the tropopause region and the stratosphere. HTAP ozone is in good agreement with observations in the troposphere within their range of uncertainty, but ozone peaks too early in the Northern Hemisphere spring. The strong gradients of ozone around the tropopause are less well captured by many models. Lower stratospheric ozone is overestimated for all regions by the multi-model mean of CCMVal2 models. Individual models also show major shortcomings in

  3. Seasonal streamflow forecasting by conditioning climatology with precipitation indices

    Science.gov (United States)

    Crochemore, Louise; Ramos, Maria-Helena; Pappenberger, Florian; Perrin, Charles

    2017-03-01

    Many fields, such as drought-risk assessment or reservoir management, can benefit from long-range streamflow forecasts. Climatology has long been used in long-range streamflow forecasting. Conditioning methods have been proposed to select or weight relevant historical time series from climatology. They are often based on general circulation model (GCM) outputs that are specific to the forecast date due to the initialisation of GCMs on current conditions. This study investigates the impact of conditioning methods on the performance of seasonal streamflow forecasts. Four conditioning statistics based on seasonal forecasts of cumulative precipitation and the standardised precipitation index were used to select relevant traces within historical streamflows and precipitation respectively. This resulted in eight conditioned streamflow forecast scenarios. These scenarios were compared to the climatology of historical streamflows, the ensemble streamflow prediction approach and the streamflow forecasts obtained from ECMWF System 4 precipitation forecasts. The impact of conditioning was assessed in terms of forecast sharpness (spread), reliability, overall performance and low-flow event detection. Results showed that conditioning past observations on seasonal precipitation indices generally improves forecast sharpness, but may reduce reliability, with respect to climatology. Conversely, conditioned ensembles were more reliable but less sharp than streamflow forecasts derived from System 4 precipitation. Forecast attributes from conditioned and unconditioned ensembles are illustrated for a case of drought-risk forecasting: the 2003 drought in France. In the case of low-flow forecasting, conditioning results in ensembles that can better assess weekly deficit volumes and durations over a wider range of lead times.

  4. Intercomparison of state-of-the-art models for wind energy resources with mesoscale models:

    Science.gov (United States)

    Olsen, Bjarke Tobias; Hahmann, Andrea N.; Sempreviva, Anna Maria; Badger, Jake; Joergensen, Hans E.

    2016-04-01

    vertical resolution, model parameterizations, surface roughness length) that could be used to group the various models and interpret the results of the intercomparison. 3. Main body abstract Twenty separate entries were received by the deadline of 31 March 2015. They included simulations done with various versions of the Weather Research and Forecast (WRF) model, but also of six other well-known mesoscale models. The various entries represent an excellent sample of the various models used in by the wind energy industry today. The analysis of the submitted time series included comparison to observations, summarized with well-known measures such as biases, RMSE, correlations, and of sector-wise statistics, e.g. frequency and Weibull A and k. The comparison also includes the observed and modeled temporal spectra. The various statistics were grouped as a function of the various models, their spatial resolution, forcing data, and the various integration methods. Many statistics have been computed and will be presented in addition to those shown in the Helsinki presentation. 4. Conclusions The analysis of the time series from twenty entries has shown to be an invaluable source of information about state of the art in wind modeling with mesoscale models. Biases between the simulated and observed wind speeds at hub heights (80-100 m AGL) from the various models are around ±1.0 m/s and fairly independent of the site and do not seem to be directly related to the model horizontal resolution used in the modeling. As probably expected, the wind speeds from the simulations using the various version of the WRF model cluster close to each other, especially in their description of the wind profile.

  5. Analysis of Historical Climatological Records In The Carpathian Basin Based On The RÉthly Collection For The Last 1000 Years

    Science.gov (United States)

    Bartholy, J.; Pongrácz, R.; Molnár, Zs.

    It is undeniable that human activities are significantly and vitally affected by extreme climatological events. People usually notice the large and abrupt changes in regional climate. Therefore, in historical documents, diaries, letters or other written reports extremes are very often mentioned and probably more or less objectively recorded. These historical sources can be used to evaluate the extreme climatic events of the last millenium. Antal Réthly made detailed documentary research on the climatological extremes oc- curred in the Carpathian Basin during the last 1000 years. He collected historical doc- uments related to meteorology and climatology into a four-volume-long book, titled "Meteorological events and natural disasters in Hungary". In order to facilitate compu- tational research of these documentary sources a special code system using hierarchi- cal subclasses have been defined and applied to the almost 15000 collected items and as a result the entire information have been digitalized and stored on computer devices for further analysis. First, we focused on precipitation, temperature and other climatic variables separately. Two-thirds of the documentary information are related to pre- cipitation (extreme precipitation, floods, thunderstorms, snowstorms, hails, droughts). The remainder one-third data provide information on temperature or wind. Spatial and temporal distribution of climatological extremes occurred in the Carpathian Basin in the last millenium have been investigated. Among others, relative frequencies of thunderstorms, hails and snowstorms have been determined and com- pared for each century. Hence long-time changes of regional climate can be demon- strated. Then, various combinations of climatic variables resulting severe climatologi- cal events (e.g., floods and droughts) have been analyzed both spatially and temporally.

  6. Simulated CONUS Flash Flood Climatologies from Distributed Hydrologic Models

    Science.gov (United States)

    Flamig, Z.; Gourley, J. J.; Vergara, H. J.; Kirstetter, P. E.; Hong, Y.

    2016-12-01

    This study will describe a CONUS flash flood climatology created over the period from 2002 through 2011. The MRMS reanalysis precipitation dataset was used as forcing into the Ensemble Framework For Flash Flood Forecasting (EF5). This high resolution 1-sq km 5-minute dataset is ideal for simulating flash floods with a distributed hydrologic model. EF5 features multiple water balance components including SAC-SMA, CREST, and a hydrophobic model all coupled with kinematic wave routing. The EF5/SAC-SMA and EF5/CREST water balance schemes were used for the creation of dual flash flood climatologies based on the differing water balance principles. For the period from 2002 through 2011 the daily maximum streamflow, unit streamflow, and time of peak streamflow was stored along with the minimum soil moisture. These variables are used to describe the states of the soils right before a flash flood event and the peak streamflow that was simulated during the flash flood event. The results will be shown, compared and contrasted. The resulting model simulations will be verified on basins less than 1,000-sq km with USGS gauges to ensure the distributed hydrologic models are reliable. The results will also be compared spatially to Storm Data flash flood event observations to judge the degree of agreement between the simulated climatologies and observations.

  7. Wind Atlas for South Africa (WASA) Observational wind atlas for 10 met. stations in Northern, Western and Eastern Cape provinces

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling; Hansen, Jens Carsten; Kelly, Mark C.;

    Program (WAsP 10). The wind-climatological inputs are the observed wind climates derived from the WAsP Climate Analyst. Topographical inputs are elevation maps constructed from SRTM 3 data and roughness length maps constructed from SWBD data and Google Earth satellite imagery. Summaries are given...... of the data measured at the 10 masts for the reference period October 2010 to September 2011. The main result of the microscale modelling is observational wind atlas data sets, which can be used for verification of the mesoscale modelling. In addition, the microscale modelling itself has been verified...

  8. Wind Atlas for South Africa (WASA) Observational wind atlas for 10 met. stations in Northern, Western and Eastern Cape provinces

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling; Hansen, Jens Carsten; Kelly, Mark C.;

    Program (WAsP 11). The wind-climatological inputs are the observed wind climates derived from the WAsP Climate Analyst. Topographical inputs are elevation maps constructed from SRTM 3 data and roughness length maps constructed from SWBD data and Google Earth satellite imagery. Summaries are given...... of the data measured at the 10 masts, mainly for a 3-year reference period from October 2010 to September 2013. The main result of the microscale modelling is observational wind atlas data sets, which can be used for verification of the mesoscale modelling. In addition, the microscale modelling itself has...

  9. Long-term climatology of air mass transport through the Tropical Tropopause Layer (TTL during NH winter

    Directory of Open Access Journals (Sweden)

    K. Krüger

    2007-09-01

    Full Text Available A long-term climatology of air mass transport through the tropical tropopause layer (TTL is presented, covering the period from 1962–2005. The transport through the TTL is calculated with a Lagrangian approach using radiative heating rates as vertical velocities in an isentropic trajectory model. We demonstrate the improved performance of such an approach compared to previous studies using vertical winds from meteorological analyses. Within the TTL, the averaged diabatic ascent is 0.5 K/day during Northern Hemisphere (NH winters 1992–2001, close to observations from the tape recorder. Climatological maps show a cooling and strengthening of this part of the residual circulation during the late 1990s and early 2000s compared to the long-term mean. Lagrangian cold point (LCP fields show systematic differences for varying time periods and natural forcing components. The interannual variability of LCP temperature and density fields are found to be influenced by volcanic eruptions, ENSO, QBO and the solar cycle. The coldest and driest TTL is reached during QBOE and La Niña over the western Pacific, whereas during volcanic eruptions, El Niño and QBOW it is warmer and less dry.

  10. Long-term climatology of air mass transport through the Tropical Tropopause Layer (TTL during NH winter

    Directory of Open Access Journals (Sweden)

    K. Krüger

    2008-02-01

    Full Text Available A long-term climatology of air mass transport through the tropical tropopause layer (TTL is presented, covering the period from 1962–2005. The transport through the TTL is calculated with a Lagrangian approach using radiative heating rates as vertical velocities in an isentropic trajectory model. We demonstrate the improved performance of such an approach compared to previous studies using vertical winds from meteorological analyses. Within the upper part of the TTL, the averaged diabatic ascent is 0.5 K/day during Northern Hemisphere (NH winters 1992–2001. Climatological maps show a cooling and strengthening of this part of the residual circulation during the 1990s and early 2000s compared to the long-term mean. Lagrangian cold point (LCP fields show systematic differences for varying time periods and natural forcing components. The interannual variability of LCP temperature and density fields is found to be influenced by volcanic eruptions, El Niño Southern Oscillation (ENSO, Quasi-Biennial Oscillation (QBO and the solar cycle. The coldest and driest TTL is reached during QBO easterly phase and La Niña over the western Pacific, whereas during volcanic eruptions, El Niño and QBO westerly phase it is warmer and less dry.

  11. Climatology of salt transitions and implications for stone weathering

    Energy Technology Data Exchange (ETDEWEB)

    Grossi, C.M., E-mail: c.grossi-sampedro@uea.ac.uk [School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Brimblecombe, P. [School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Menendez, B. [Geosciences et Environnement Cergy, Universite de Cergy-Pontoise 95031 Cergy-Pontoise cedex (France); Benavente, D. [Lab. Petrologia Aplicada, Unidad Asociada UA-CSIC, Dpto. Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Alicante 03080 (Spain); Harris, I. [Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Deque, M. [Meteo-France/CNRM, CNRS/GAME, 42 Avenue Coriolis, F-31057 Toulouse, Cedex 01 (France)

    2011-06-01

    This work introduces the notion of salt climatology. It shows how climate affects salt thermodynamic and the potential to relate long-term salt damage to climate types. It mainly focuses on specific sites in Western Europe, which include some cities in France and Peninsular Spain. Salt damage was parameterised using the number of dissolution-crystallisation events for unhydrated (sodium chloride) and hydrated (sodium sulphate) systems. These phase transitions have been calculated using daily temperature and relative humidity from observation meteorological data and Climate Change models' output (HadCM3 and ARPEGE). Comparing the number of transitions with meteorological seasonal data allowed us to develop techniques to estimate the frequency of salt transitions based on the local climatology. Results show that it is possible to associate the Koeppen-Geiger climate types with potential salt weathering. Temperate fully humid climates seem to offer the highest potential for salt damage and possible higher number of transitions in summer. Climates with dry summers tend to show a lesser frequency of transitions in summer. The analysis of temperature, precipitation and relative output from Climate Change models suggests changes in the Koeppen-Geiger climate types and changes in the patterns of salt damage. For instance, West Europe areas with a fully humid climate may change to a more Mediterranean like or dry climates, and consequently the seasonality of different salt transitions. The accuracy and reliability of the projections might be improved by simultaneously running multiple climate models (ensembles). - Research highlights: {yields} We introduce the notion of salt climatology for heritage conservation. {yields} Climate affects salt thermodynamics on building materials. {yields} We associate Koeppen-Geiger climate types with potential salt weathering. {yields} We offer future projections of salt damage in Western Europe due to climate change. {yields} Humid

  12. A simplified approach for generating GNSS radio occultation refractivity climatologies

    Directory of Open Access Journals (Sweden)

    H. Gleisner

    2012-07-01

    Full Text Available The possibility of simplifying the retrieval scheme required to produce GNSS radio occultation refractivity climatologies is investigated. In a new, simplified retrieval approach, the main statistical analysis is performed in bending angle space and an estimate of the average bending angle profile is then propagated through an Abel transform. The average is composed of means and medians of ionospheric corrected bending angles up to 80 km. Above that, the observed profile is exponentially extrapolated to infinity using a fixed a priori scale height. The new approach circumvents the need to introduce a "statistical optimization" processing step in which individual bending-angle profiles are merged with a priori data, often taken from a climatology. This processing step can be complex, difficult to interpret, and is generally recognized as a potential source of structural uncertainty. The new scheme is compared with the more conventional approach of averaging individual refractivity profiles, produced with the implementation of statistical optimization used in the EUMETSAT Radio Occultation Meteorology Satellite Application Facility (ROM SAF operational processing. It is shown that the two GNSS radio occultation climatologies agree to within 0.1% from 5 km up to 35–40 km, for the three months January, February, and March 2011. During this time period, the new approach also produces slightly better agreement with ECMWF analyses between 40–50 km, which is encouraging. The possible limitations of the new approach caused by mean residual ionospheric errors and low observation numbers are discussed briefly, and areas for future work are suggested.

  13. An Oceanographic and Climatological Atlas of Bristol Bay

    Science.gov (United States)

    1987-10-01

    Report No. C_-_1_8 AN OCEANOGRAPHIC AND CLIMATOLOGICAL " ATLAS OF BRISTOL BAY JAMES L. WIFE LYNN D. LESLIE JOSEPH C. LABELLE Arctic Environmental...Performing Organization Report No. 7. Author(s) James L. Wise, Lynn D. Leslie , and Joseph C. LaBelle R&DC 16/87 9. Performing Organization Name and...experience. 39 Coastal Sectors for Storm Surge Forecasting 170 1650 160~ 155’ Cape Romanzof Hooper Bay Bethel IISLAND I SLAND Ki n k 1 un a aSETO I~Cp

  14. CLIMATOLOGICAL DIAGNOSIS OF WINTER TEMPERATURE VARIATIONS IN GUANGDONG

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Using the monthly mean and minimum temperature data of the 36 observation stations in Guangdong, the climatological features of the temperatures have been analyzed, including characteristics of trends, abrupt changes and periods. And the possible affecting factors on the winter warming in Guangdong have been discussed. The results show that the winter temperatures, particularly the monthly mean minimum temperatures in Guangdong, have a warming trend. The rise of the winter minimum temperatures in Guangdong began in the second half of 1960's and the warming was more evident since the 1980's.

  15. The climatology of planetary boundary layer height in China derived from radiosonde and reanalysis data

    Science.gov (United States)

    Guo, Jianping; Miao, Yucong; Zhang, Yong; Liu, Huan; Li, Zhanqing; Zhang, Wanchun; He, Jing; Lou, Mengyun; Yan, Yan; Bian, Lingen; Zhai, Panmao

    2016-10-01

    The important roles of the planetary boundary layer (PBL) in climate, weather and air quality have long been recognized, but little is known about the PBL climatology in China. Using the fine-resolution sounding observations made across China and reanalysis data, we conducted a comprehensive investigation of the PBL in China from January 2011 to July 2015. The boundary layer height (BLH) is found to be generally higher in spring and summer than that in fall and winter. The comparison of seasonally averaged BLHs derived from observations and reanalysis, on average, shows good agreement, despite the pronounced inconsistence in some regions. The BLH, derived from soundings conducted three or four times daily in summer, tends to peak in the early afternoon, and the diurnal amplitude of BLH is higher in the northern and western subregions of China than other subregions. The meteorological influence on the annual cycle of BLH is investigated as well, showing that BLH at most sounding sites is negatively associated with the surface pressure and lower tropospheric stability, but positively associated with the near-surface wind speed and temperature. In addition, cloud tends to suppress the development of PBL, particularly in the early afternoon. This indicates that meteorology plays a significant role in the PBL processes. Overall, the key findings obtained from this study lay a solid foundation for us to gain a deep insight into the fundamentals of PBL in China, which helps to understand the roles that the PBL plays in the air pollution, weather and climate of China.

  16. The climatological mean atmospheric transport under weakened Atlantic thermohaline circulation climate scenario

    Energy Technology Data Exchange (ETDEWEB)

    Erukhimova, T. [Texas A and M University, Department of Physics, College Station, TX (United States); Zhang, R. [GFDL/NOAA, Princeton, NJ (United States); Bowman, K.P. [Texas A and M University, Department of Atmospheric Sciences, College Station, TX (United States)

    2009-02-15

    Global atmospheric transport in a climate subject to a substantial weakening of the Atlantic thermohaline circulation (THC) is studied by using climatological Green's functions of the mass conservation equation for a conserved, passive tracer. Two sets of Green's functions for the perturbed climate and for the present climate are evaluated from 11-year atmospheric trajectory calculations, based on 3-D winds simulated by GFDL's newly developed global coupled ocean-atmosphere model (CM2.1). The Green's function analysis reveals pronounced effects of the climate change on the atmospheric transport, including seasonally modified Hadley circulation with a stronger Northern Hemisphere cell in DJF and a weaker Southern Hemisphere cell in JJA. A weakened THC is also found to enhance mass exchange rates through mixing barriers between the tropics and the two extratropical zones. The response in the tropics is not zonally symmetric. The 3-D Green's function analysis of the effect of THC weakening on transport in the tropical Pacific shows a modified Hadley cell in the eastern Pacific, confirming the results of our previous studies, and a weakening (strengthening) of the upward and eastward motion to the south (north) of the Equator in the western Pacific in the perturbed climate as compared to the present climate. (orig.)

  17. The application of low-rank and sparse decomposition method in the field of climatology

    Science.gov (United States)

    Gupta, Nitika; Bhaskaran, Prasad K.

    2017-03-01

    The present study reports a low-rank and sparse decomposition method that separates the mean and the variability of a climate data field. Until now, the application of this technique was limited only in areas such as image processing, web data ranking, and bioinformatics data analysis. In climate science, this method exactly separates the original data into a set of low-rank and sparse components, wherein the low-rank components depict the linearly correlated dataset (expected or mean behavior), and the sparse component represents the variation or perturbation in the dataset from its mean behavior. The study attempts to verify the efficacy of this proposed technique in the field of climatology with two examples of real world. The first example attempts this technique on the maximum wind-speed (MWS) data for the Indian Ocean (IO) region. The study brings to light a decadal reversal pattern in the MWS for the North Indian Ocean (NIO) during the months of June, July, and August (JJA). The second example deals with the sea surface temperature (SST) data for the Bay of Bengal region that exhibits a distinct pattern in the sparse component. The study highlights the importance of the proposed technique used for interpretation and visualization of climate data.

  18. Ground validation of oceanic snowfall detection in satellite climatologies during LOFZY

    Science.gov (United States)

    Klepp, Christian; Bumke, Karl; Bakan, Stephan; Bauer, Peter

    2010-08-01

    A thorough knowledge of global ocean precipitation is an indispensable prerequisite for the understanding of the water cycle in the global climate system. However, reliable detection of precipitation over the global oceans, especially of solid precipitation, remains a challenging task. This is true for both, passive microwave remote sensing and reanalysis based model estimates. The optical disdrometer ODM 470 is a ground validation instrument capable of measuring rain and snowfall on ships even under high wind speeds. It was used for the first time over the Nordic Seas during the LOFZY 2005 campaign. A dichotomous verification of precipitation occurrence resulted in a perfect correspondence between the disdrometer, a precipitation detector and a shipboard observer's log. The disdrometer data is further point-to-area collocated against precipitation from the satellite based Hamburg Ocean Atmosphere Parameters and fluxes from Satellite data (HOAPS) climatology. HOAPS precipitation turns out to be overall consistent with the disdrometer data resulting in a detection accuracy of 0.96. The collocated data comprises light precipitation events below 1 mm h-1. Therefore two LOFZY case studies with high precipitation rates are presented that indicate plausible HOAPS satellite precipitation rates. Overall, this encourages longer term measurements of ship-to-satellite collocated precipitation in the near future.

  19. Application and verification of ECMWF seasonal forecast for wind energy

    Science.gov (United States)

    Žagar, Mark; Marić, Tomislav; Qvist, Martin; Gulstad, Line

    2015-04-01

    A good understanding of long-term annual energy production (AEP) is crucial when assessing the business case of investing in green energy like wind power. The art of wind-resource assessment has emerged into a scientific discipline on its own, which has advanced at high pace over the last decade. This has resulted in continuous improvement of the AEP accuracy and, therefore, increase in business case certainty. Harvesting the full potential output of a wind farm or a portfolio of wind farms depends heavily on optimizing operation and management strategy. The necessary information for short-term planning (up to 14 days) is provided by standard weather and power forecasting services, and the long-term plans are based on climatology. However, the wind-power industry is lacking quality information on intermediate scales of the expected variability in seasonal and intra-annual variations and their geographical distribution. The seasonal power forecast presented here is designed to bridge this gap. The seasonal power production forecast is based on the ECMWF seasonal weather forecast and the Vestas' high-resolution, mesoscale weather library. The seasonal weather forecast is enriched through a layer of statistical post-processing added to relate large-scale wind speed anomalies to mesoscale climatology. The resulting predicted energy production anomalies, thus, include mesoscale effects not captured by the global forecasting systems. The turbine power output is non-linearly related to the wind speed, which has important implications for the wind power forecast. In theory, the wind power is proportional to the cube of wind speed. However, due to the nature of turbine design, this exponent is close to 3 only at low wind speeds, becomes smaller as the wind speed increases, and above 11-13 m/s the power output remains constant, called the rated power. The non-linear relationship between wind speed and the power output generally increases sensitivity of the forecasted power

  20. Statistical Short-Range Guidance for Peak Wind Speed Forecasts at Edwards Air Force Base, CA

    Science.gov (United States)

    Dreher, Joseph; Crawford, Winifred; Lafosse, Richard; Hoeth, Brian; Burns, Kerry

    2008-01-01

    The peak winds near the surface are an important forecast element for Space Shuttle landings. As defined in the Shuttle Flight Rules (FRs), there are peak wind thresholds that cannot be exceeded in order to ensure the safety of the shuttle during landing operations. The National Weather Service Spaceflight Meteorology Group (SMG) is responsible for weather forecasts for all shuttle landings. They indicate peak winds are a challenging parameter to forecast. To alleviate the difficulty in making such wind forecasts, the Applied Meteorology Unit (AMTJ) developed a personal computer based graphical user interface (GUI) for displaying peak wind climatology and probabilities of exceeding peak-wind thresholds for the Shuttle Landing Facility (SLF) at Kennedy Space Center. However, the shuttle must land at Edwards Air Force Base (EAFB) in southern California when weather conditions at Kennedy Space Center in Florida are not acceptable, so SMG forecasters requested that a similar tool be developed for EAFB. Marshall Space Flight Center (MSFC) personnel archived and performed quality control of 2-minute average and 10-minute peak wind speeds at each tower adjacent to the main runway at EAFB from 1997- 2004. They calculated wind climatologies and probabilities of average peak wind occurrence based on the average speed. The climatologies were calculated for each tower and month, and were stratified by hour, direction, and direction/hour. For the probabilities of peak wind occurrence, MSFC calculated empirical and modeled probabilities of meeting or exceeding specific 10-minute peak wind speeds using probability density functions. The AMU obtained and reformatted the data into Microsoft Excel PivotTables, which allows users to display different values with point-click-drag techniques. The GUT was then created from the PivotTables using Visual Basic for Applications code. The GUI is run through a macro within Microsoft Excel and allows forecasters to quickly display and

  1. Wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Yeoman, J.C. Jr.

    1978-12-01

    This evaluation of wind turbines is part of a series of Technology Evaluations of possible components and subsystems of community energy systems. Wind turbines, ranging in size from 200 W to 10 MW, are discussed as candidates for prime movers in community systems. Estimates of performance characteristics and cost as a function of rated capacity and rated wind speed are presented. Data concerning material requirements, environmental effects, and operating procedures also are given and are represented empirically to aid computer simulation.

  2. Meridional Winds derived from ionosonde measurements: comparison of different models

    Science.gov (United States)

    Katamzi, Zama; Bosco Habarulema, John; Aruliah, Anasuya

    2016-07-01

    Thermospheric meridional winds are derived from ionospheric F2 region peak parameters (i.e. F2 maximum density, NmF2, and F2 peak height, hmF2) obtained using South African ionosonde for solar maximum (2001 and 2014) and solar minimum (2009). The study uses several different techniques and models to investigate the climatology behaviour of the winds in order to understand wind variability over South Africa. Detailed solar cycle, seasonal and diurnal trends will help establish how the winds influence ionospheric behaviour at this latitude. Comparisons of ionosonde derived neutral winds with empirical and numerical models such as the Coupled Middle Atmosphere Thermosphere Model (CMAT2) and Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) are important to understand the validity of theoretical and empirical models.

  3. The near-surface wind field over the Antarctic continent

    Science.gov (United States)

    van Lipzig, N. P. M.; Turner, J.; Colwell, S. R.; van den Broeke, M. R.

    2004-12-01

    A 14 year integration with a regional atmospheric model has been used to determine the near-surface climatological wind field over the Antarctic ice sheet at a horizontal grid spacing of 55 km. Previous maps of the near-surface wind field were generally based on models ignoring the large-scale pressure-gradient forcing term in the momentum equation. Presently, state-of-the-art atmospheric models include all pressure-gradient forcing terms. Evaluation of our model output against in situ data shows that the model is able to represent realistically the observed increase in wind speed going from the interior to the coast, as well as the observed wind direction at South Pole and Dumont d'Urville and the bimodal wind distribution at Halley.

  4. Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Ganley, Jason; Zhang, Jie; Hodge, Bri-Mathias

    2016-03-15

    Wind energy is a variable and uncertain renewable resource that has long been used to produce mechanical work, and has developed into a large producer of global electricity needs. As renewable sources of energy and feedstocks become more important globally to produce sustainable products, many different processes have started adopting wind power as an energy source. Many times this is through a conversion to hydrogen through electrolysis that allows for a more continuous process input. Other important pathways include methanol and ammonia. As the demand for sustainable products and production pathways increases, and wind power capital costs decrease, the role of wind power in chemical and energy production seems poised to increase significantly.

  5. Changes in Surface Wind Speed over North America from CMIP5 Model Projections and Implications for Wind Energy

    Directory of Open Access Journals (Sweden)

    Sujay Kulkarni

    2014-01-01

    Full Text Available The centennial trends in the surface wind speed over North America are deduced from global climate model simulations in the Climate Model Intercomparison Project—Phase 5 (CMIP5 archive. Using the 21st century simulations under the RCP 8.5 scenario of greenhouse gas emissions, 5–10 percent increases per century in the 10 m wind speed are found over Central and East-Central United States, the Californian Coast, and the South and East Coasts of the USA in winter. In summer, climate models projected decreases in the wind speed ranging from 5 to 10 percent per century over the same coastal regions. These projected changes in the surface wind speed are moderate and imply that the current estimate of wind power potential for North America based on present-day climatology will not be significantly changed by the greenhouse gas forcing in the coming decades.

  6. A Statistical Aggregation Engine for Climatology and Trend Analysis

    Science.gov (United States)

    Chapman, D. R.; Simon, T. A.; Halem, M.

    2014-12-01

    Fundamental climate data records (FCDRs) from satellite instruments often span tens to hundreds of terabytes or even petabytes in scale. These large volumes make it difficult to aggregate or summarize their climatology and climate trends. It is especially cumbersome to supply the full derivation (provenance) of these aggregate calculations. We present a lightweight and resilient software platform, Gridderama that simplifies the calculation of climatology by exploiting the "Data-Cube" topology often present in earth observing satellite records. By using the large array storage (LAS) paradigm, Gridderama allows the analyst to more easily produce a series of aggregate climate data products at progressively coarser spatial and temporal resolutions. Furthermore, provenance tracking and extensive visualization capabilities allow the analyst to track down and correct for data problems such as missing data and outliers that may impact the scientific results. We have developed and applied Gridderama to calculate a trend analysis of 55 Terabytes of AIRS Level 1b infrared radiances, and show statistically significant trending in the greenhouse gas absorption bands as observed by AIRS over the 2003-2012 decade. We will extend this calculation to show regional changes in CO2 concentration from AIRS over the 2003-2012 decade by using a neural network retrieval algorithm.

  7. A New Global Climatology of Annual Land Surface Temperature

    Directory of Open Access Journals (Sweden)

    Benjamin Bechtel

    2015-03-01

    Full Text Available Land surface temperature (LST is an important parameter in various fields including hydrology, climatology, and geophysics. Its derivation by thermal infrared remote sensing has long tradition but despite substantial progress there remain limited data availability and challenges like emissivity estimation, atmospheric correction, and cloud contamination. The annual temperature cycle (ATC is a promising approach to ease some of them. The basic idea to fit a model to the ATC and derive annual cycle parameters (ACP has been proposed before but so far not been tested on larger scale. In this study, a new global climatology of annual LST based on daily 1 km MODIS/Terra observations was processed and evaluated. The derived global parameters were robust and free of missing data due to clouds. They allow estimating LST patterns under largely cloud-free conditions at different scales for every day of year and further deliver a measure for its accuracy respectively variability. The parameters generally showed low redundancy and mostly reflected real surface conditions. Important influencing factors included climate, land cover, vegetation phenology, anthropogenic effects, and geology which enable numerous potential applications. The datasets will be available at the CliSAP Integrated Climate Data Center pending additional processing.

  8. Characteristics of cyclone climatology and variability in the Southern Ocean

    Institute of Scientific and Technical Information of China (English)

    WEI Lixin; QIN Ting

    2016-01-01

    A new climatology of cyclones in the Southern Ocean is generated by applying an automated cyclone detection and tracking algorithm (developed by Hodges at the Reading University) for an improved and relatively high-resolution European Centre for Medium-Range Weather Forecasts atmospheric reanalysis during 1979–2013. A validation shows that identified cyclone tracks are in good agreement with a available analyzed cyclone product. The climatological characteristics of the Southern Ocean cyclones are then analyzed, including track, number, density, intensity, deepening rate and explosive events. An analysis shows that the number of cyclones in the Southern Ocean has increased for 1979–2013, but only statistically significant in summer. Coincident with the circumpolar trough, a single high-density band of cyclones is observed in 55°–67°S, and cyclone density has generally increased in north of this band for 1979–2013, except summer. The intensity of up to 70% cyclones in the Southern Ocean is less than 980 hPa, and only a few cyclones with pressure less than 920 hPa are detected for 1979–2013. Further analysis shows that a high frequency of explosive cyclones is located in the band of 45°–55°S, and the Atlantic Ocean sector has much higher frequent occurrence of the explosive cyclones than that in the Pacific Ocean sector. Additionally, the relationship between cyclone activities in the Southern Ocean and the Southern Annular Mode is discussed.

  9. California's wind energy resource: seasonal, synoptic, and diurnal characteristics, and variability on several time scales

    Science.gov (United States)

    Mansbach, D. K.; Cayan, D. R.

    2009-12-01

    Decades worth of observational data are used to analyze the annual cycle, relevant synoptic climatology, and diurnal patterns of wind in California's major wind generation regions. Wind records near the wind farms at San Gorgonio and Tehachapi passes, Southern California, and Solano County, Northern California near Sacramento are employed. The in situ data are complemented by global reanalysis, 10-km dynamically downscaled regional reanalysis, and other weather station and buoy data. Each site shows preferred wind directions dictated by local orographic forcing as well as different peaks in wind speed and direction distribution in each season, which are explained in terms of climatological circulation patterns. All have greater wind energy in the warmer months, although the northern site peaks later in the summer, more in phase with the temperature cycle but lagging the cycle in zonal SLP gradient that the other sites align with. The dominant patterns associated with high winds, classified with self-organizing maps, feature a North Pacific SLP high and western North American low. The interplay between synoptic forcing and local circulations is also explored. Local circulations are especially important in the warm months when mesoscale SLP gradients are set up by diurnal heating. The northernmost site displays sharp diurnal wind increases as remnants of a sea breeze propagate inland to the site and amplify the wind induced by the cross-valley SLP gradient.

  10. Zonal winds in the equatorial upper thermosphere: Decomposing the solar flux, geomagnetic activity, and seasonal dependencies

    NARCIS (Netherlands)

    Liu, H.; Lühr, H.; Watanabe, S.; Köhler, W.; Henize, V.; Visser, P.N.A.M.

    2006-01-01

    Using 3 years (2002–2004), over 16,400 orbits of measurements from the accelerometer on board the CHAMP satellite, we have studied the climatology of the equatorial zonal wind in the upper thermosphere. Several main features are noticed. The most prominent one is that the solar flux significantly in

  11. Comparison among four kinds of data of sea surface wind stress in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    谢强; 王卫强; 毛庆文

    2002-01-01

    By using remote sensing (ERS) data, FSU data, GOADS data and Hellerman & Rcsenstein objective analysis data to analyze the sea surface wind stress in the South China Sea, it is found that the remote sensing data have higher resolution and more reasonable values. Therefore we suggest that remote sensing data be chosen in the study of climatological features of sea surface wind stress and its seasonal variability in the South China Sea, especially in the study of small and middle scale eddies.

  12. Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low generation limits.

    Science.gov (United States)

    Miller, Lee M; Kleidon, Axel

    2016-11-29

    Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power limits that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 We m(-2)) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 We m(-2)) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power use can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 We m(-2) of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power.

  13. Harnessing Wind

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China’s wind power industry shifts into full gear The global oil crunch and environmental degradation have given rise to an ardent search for alternative and green energies throughout the world. For China, wind power is a choice one and its development is sizzling hot backed by

  14. Long-term dust climatology in the western United States reconstructed from routine aerosol ground monitoring

    Directory of Open Access Journals (Sweden)

    D. Q. Tong

    2012-06-01

    Full Text Available This study introduces an observation-based dust identification approach and applies it to reconstruct long-term dust climatology in the western United States. Long-term dust climatology is important for quantifying the effects of atmospheric aerosols on regional and global climate. Although many routine aerosol monitoring networks exist, it is often difficult to obtain dust records from these networks, because these monitors are either deployed far away from dust active regions (most likely collocated with dense population or contaminated by anthropogenic sources and other natural sources, such as wildfires and vegetation detritus. Here we propose an approach to identify local dust events relying solely on aerosol mass and composition from general-purpose aerosol measurements. Through analyzing the chemical and physical characteristics of aerosol observations during satellite-detected dust episodes, we select five indicators to be used to identify local dust records: (1 high PM10 concentrations; (2 low PM2.5/PM10 ratio; (3 higher concentrations and percentage of crustal elements; (4 lower percentage of anthropogenic pollutants; and (5 low enrichment factors of anthropogenic elements. After establishing these identification criteria, we conduct hierarchical cluster analysis for all validated aerosol measurement data over 68 IMPROVE sites in the western United States. A total of 182 local dust events were identified over 30 of the 68 locations from 2000 to 2007. These locations are either close to the four US Deserts, namely the Great Basin Desert, the Mojave Desert, the Sonoran Desert, and the Chihuahuan Desert, or in the high wind power region (Colorado. During the eight-year study period, the total number of dust events displays an interesting four-year activity cycle (one in 2000–2003 and the other in 2004–2007. The years of 2003, 2002 and 2007 are the three most active dust periods, with 46, 31 and 24

  15. Wind energy.

    Science.gov (United States)

    Leithead, W E

    2007-04-15

    From its rebirth in the early 1980s, the rate of development of wind energy has been dramatic. Today, other than hydropower, it is the most important of the renewable sources of power. The UK Government and the EU Commission have adopted targets for renewable energy generation of 10 and 12% of consumption, respectively. Much of this, by necessity, must be met by wind energy. The US Department of Energy has set a goal of 6% of electricity supply from wind energy by 2020. For this potential to be fully realized, several aspects, related to public acceptance, and technical issues, related to the expected increase in penetration on the electricity network and the current drive towards larger wind turbines, need to be resolved. Nevertheless, these challenges will be met and wind energy will, very likely, become increasingly important over the next two decades. An overview of the technology is presented.

  16. Recent trends of the tropical hydrological cycle inferred from Global Precipitation Climatology Project and International Satellite Cloud Climatology Project data

    Science.gov (United States)

    Zhou, Y. P.; Xu, Kuan-Man; Sud, Y. C.; Betts, A. K.

    2011-05-01

    Scores of modeling studies have shown that increasing greenhouse gases in the atmosphere impact the global hydrologic cycle; however, disagreements on regional scales are large, and thus the simulated trends of such impacts, even for regions as large as the tropics, remain uncertain. The present investigation attempts to examine such trends in the observations using satellite data products comprising Global Precipitation Climatology Project precipitation and International Satellite Cloud Climatology Project cloud and radiation. Specifically, evolving trends of the tropical hydrological cycle over the last 20-30 years were identified and analyzed. The results show (1) intensification of tropical precipitation in the rising regions of the Walker and Hadley circulations and weakening over the sinking regions of the associated overturning circulation; (2) poleward shift of the subtropical dry zones (up to 2° decade-1 in June-July-August (JJA) in the Northern Hemisphere and 0.3-0.7° decade-1 in June-July-August and September-October-November in the Southern Hemisphere) consistent with an overall broadening of the Hadley circulation; and (3) significant poleward migration (0.9-1.7° decade-1) of cloud boundaries of Hadley cell and plausible narrowing of the high cloudiness in the Intertropical Convergence Zone region in some seasons. These results support findings of some of the previous studies that showed strengthening of the tropical hydrological cycle and expansion of the Hadley cell that are potentially related to the recent global warming trends.

  17. Wind Energy Resource Assessment of the Caribbean and Central America

    Energy Technology Data Exchange (ETDEWEB)

    DL Elliott; CI Aspliden; GL Gower; CG Holladay, MN Schwartz

    1987-04-01

    A wind energy resource assessment of the Caribbean and Central America has identified many areas with good to outstanding wind resource potential for wind turbine applications. Annual average wind resource maps and summary tables have been developed for 35 island/country areas throughout the Caribbean and Central America region. The wind resource maps highlight the locations of major resource areas and provide estimates of the wind energy resource potential for typical well-exposed sites in these areas. The average energy in the wind flowing in the layer near the ground is expressed as a wind power class: the greater the average wind energy, the higher the wind power class. The summary tables that are included with each of the 35 island/country wind energy maps provide information on the frequency distribution of the wind speeds (expressed as estimates of the Weibull shape factor, k) and seasonal variations in the wind resource for the major wind resource areas identified on the maps. A new wind power class legend has been developed for relating the wind power classes to values of mean wind power density, mean wind speed, and Weibull k. Guidelines are presented on how to adjust these values to various heights above ground for different roughness and terrain characteristics. Information evaluated in preparing the assessment included existing meteorological data from airports and other weather stations, and from ships and buoys in offshore and coastal areas. In addition, new data from recent measurement sites established for wind energy siting studies were obtained for a few areas of the Caribbean. Other types of information evaluated in the assessment were climatological data and maps on winds aloft, surface pressure, air flow, and topography. The various data were screened and evaluated for their usefulness in preparing the wind resource assessment. Much of the surface data from airports and other land-based weather stations were determined to be from sheltered

  18. Abstraction the public from scientific - applied meteorological-climatologic data

    Science.gov (United States)

    Trajanoska, L.

    2010-09-01

    Mathematical and meteorological statistic processing of meteorological-climatologic data, which includes assessment of the exactness, level of confidence of the average and extreme values, frequencies (probabilities) of the occurrence of each meteorological phenomenon and element e.t.c. helps to describe the impacts climate may have on different social and economic activities (transportation, heat& power generation), as well as on human health. Having in mind the new technology and the commercial world, during the work with meteorological-climatologic data we have meet many different challenges. Priority in all of this is the quality of the meteorological-climatologic set of data. First, we need compatible modern, sophisticated measurement and informatics solution for data. Results of this measurement through applied processing and analyze is the second branch which is very important also. Should we all (country) need that? Today we have many unpleasant events connected with meteorology, many questions which are not answered and all of this has too long lasting. We must give the answers and solve the real and basic issue. In this paper the data issue will be presented. We have too much of data but so little of real and quality applied of them, Why? There is a data for: -public applied -for jurisdiction needs -for getting fast decision-solutions (meteorological-dangerous phenomenon's) -for getting decisions for long-lasting plans -for explore in different sphere of human living So, it is very important for what kind of data we are talking. Does the data we are talking are with public or scientific-applied character? So,we have two groups. The first group which work with the data direct from the measurement place and instrument. They are store a quality data base and are on extra help to the journalists, medical workers, human civil engineers, electromechanical engineers, agro meteorological and forestry engineer e.g. The second group do work with all scientific

  19. Annual Climatology of the Diurnal Cycle on the Canadian Prairies

    Directory of Open Access Journals (Sweden)

    Alan K Betts

    2016-01-01

    Full Text Available We show the annual climatology of the diurnal cycle, stratified by opaque cloud, using the full hourly resolution of the Canadian Prairie data. The opaque cloud field itself has distinct cold and warm season diurnal climatologies; with a near-sunrise peak of cloud in the cold season and an early afternoon peak in the warm season. There are two primary climate states on the Canadian Prairies, separated by the freezing point of water, because a reflective surface snow cover acts as a climate switch. Both cold and warm season climatologies can be seen in the transition months of November, March and April with a large difference in mean temperature. In the cold season with snow, the diurnal ranges of temperature and relative humidity increase quasi-linearly with decreasing cloud, and increase from December to March with increased solar forcing. The warm season months, April to September, show a homogeneous coupling to the cloud cover, and a diurnal cycle of temperature and humidity that depends only on net longwave. Our improved representation of the diurnal cycle shows that the warm season coupling between diurnal temperature range and net longwave is weakly quadratic through the origin, rather than the linear coupling shown in earlier papers. We calculate the conceptually important 24-h imbalances of temperature and relative humidity (and other thermodynamic variables as a function of opaque cloud cover. In the warm season under nearly clear skies, there is a warming of +2oC and a drying of -6% over the 24-h cycle, which is about 12% of their diurnal ranges. We summarize results on conserved variable diagrams and explore the impact of surface windspeed on the diurnal cycle in the cold and warm seasons. In all months, the fall in minimum temperature is reduced with increasing windspeed, which reduces the diurnal temperature range. In July and August, there is an increase of afternoon maximum temperature and humidity at low windspeeds, and a

  20. Wind Climate in Kongsfjorden, Svalbard, and Attribution of Leading Wind Driving Mechanisms through Turbulence-Resolving Simulations

    Directory of Open Access Journals (Sweden)

    Igor Esau

    2012-01-01

    Full Text Available This paper presents analysis of wind climate of the Kongsfjorden-Kongsvegen valley, Svalbard. The Kongsfjorden-Kongsvegen valley is relatively densely covered with meteorological observations, which facilitate joint statistical analysis of the turbulent surface layer structure and the structure of the higher atmospheric layers. Wind direction diagrams reveal strong wind channeled in the surface layer up to 300 m to 500 m. The probability analysis links strong wind channeling and cold temperature anomalies in the surface layer. To explain these links, previous studies suggested the katabatic wind flow mechanism as the leading driver responsible for the observed wind climatology. In this paper, idealized turbulence-resolving simulations are used to distinct between different wind driving mechanisms. The simulations were performed with the real surface topography at resolution of about 60 m. These simulations resolve the obstacle-induced turbulence and the turbulence in the non-stratified boundary layer core. The simulations suggest the leading roles of the thermal land-sea breeze circulation and the mechanical wind channeling in the modulation of the valley winds. The characteristic signatures of the developed down-slope gravity-accelerated flow, that is, the katabatic wind, were found to be of lesser significance under typical meteorological conditions in the valley.

  1. Coastal Ohio Wind Project for Reduced Barriers to Deployment of Offshore Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Gorsevski, Peter; Afjeh, Abdollah; Jamali, Mohsin; Carroll, Michael

    2014-04-09

    mitigate adverse effects of ice formation on wind turbine structures. Firstly, a Zephir LiDAR system was acquired and installed at Woodlands School in Huron, Ohio, which is located near Lake Erie. Wind resource data were obtained at ten measurement heights, 200m, 150m, 100m, 80m, 60m, 40m, 38m, 30m, 20m, and 10m. The Woodlands School’s wind turbine anemometer also measured the wind speed at the hub height. These data were collected for approximately one year. The hub anemometer data correlated well with the LiDAR wind speed measurements at the same height. The data also showed that on several days different power levels were recorded by the turbine at the same wind speed as indicated by the hub anemometer. The corresponding LiDAR data showed that this difference can be attributed to variability in the wind over the turbine rotor swept area, which the hub anemometer could not detect. The observation suggests that single point hub wind velocity measurements are inadequate to accurately estimate the power generated by a turbine at all times since the hub wind speed is not a good indicator of the wind speed over the turbine rotor swept area when winds are changing rapidly. To assess the effectiveness of ice coatings to mitigate the impact of ice on turbine structures, a closed-loop icing research tunnel (IRT) was designed and constructed. By controlling the temperature, air speed, water content and liquid droplet size, the tunnel enabled consistent and repeatable ice accretion under a variety of conditions with temperatures between approximately 0°C and -20°C and wind speeds up to 40 miles per hour in the tunnel’s test section. The tunnel’s cooling unit maintained the tunnel temperature within ±0.2°C. The coatings evaluated in the study were Boyd Coatings Research Company’s CRC6040R3, MicroPhase Coatings Inc.’s PhaseBreak TP, ESL and Flex coatings. Similar overall performance was observed in all coatings tested in that water droplets form on the test articles

  2. Dust Climatology of the NASA Dryden Flight Research Center (DFRC in Lancaster, California, USA

    Directory of Open Access Journals (Sweden)

    Ashok K. Pokharel

    2017-02-01

    Full Text Available Abstract: A 15-year (1997–2011 climatology of dust events at the NASA DFRC in Lancaster, California, USA, was performed to evaluate how the extratropical systems were associated with dust storms over this region. For this study, we collected meteorological data for Edwards Air Force Base (EAFB in Lancaster, California, which is very close to NASA DFRC, from wunderground.com, National Centers for Environmental Prediction (NCEP/North American Regional Reanalysis (NARR, NCEP/Hydro-meteorological Prediction Center/National Weather Service (NWS, and Unisys analyses. We find that the dust events were associated with the development of a deep convective boundary layer, turbulence kinetic energy (TKE ≥3 J/kg, a deep unstable lapse rate layer, a wind speed above the frictional threshold wind speed necessary to ablate dust from the surface (≥7.3 m/s, a presence of a cold trough above the deep planetary boundary layer (PBL, a strong cyclonic jet, an influx of vertical sensible heat from the surrounding area, and a low volumetric soil moisture fraction <0.3. The annual mean number of dust events, their mean duration, and the unit duration per number of event for each visibility range, when binned as <11.2 km, <8 km, <4.8 km, <1.6 km, and <1 km were calculated. The visibility range values were positively correlated with the annual mean number of dust events, duration of dust events, and the ratio of duration of dust events. The percentage of the dust events by season shows that most of the dust events occurred in autumn (44.7%, followed by spring (38.3%, and equally in summer and winter with these seasons each accounting for 8.5% of events. This study also shows that the summer had the highest percentage (10% of the lowest visibility condition (<1 km followed by autumn (2%. Neither of the other two seasons—winter and spring—experienced such a low visibility condition during the entire dust events over 15 years. Winter had the highest visibility

  3. Improved Climatological Characterization of Optical Turbulence for Space Optical Imaging and Communications

    Science.gov (United States)

    Alliss, R.; Felton, B.

    2010-09-01

    Optical turbulence (OT) acts to distort light in the atmosphere, degrading imagery from astronomical or other telescopes. In addition, the quality of service of a free space optical communications link may also be impacted. Some of the degradation due to turbulence can be corrected by adaptive optics. However, the severity of optical turbulence, and thus the amount of correction required, is largely dependent upon the turbulence at the location of interest. Therefore, it is vital to understand the climatology of optical turbulence at such locations. In many cases, it is impractical and expensive to setup instrumentation to characterize the climatology of OT, particularly for OCONUS locations, so simulations become a less expensive and convenient alternative. The strength of OT is characterized by the refractive index structure function Cn2, which in turn is used to calculate atmospheric seeing parameters. While attempts have been made to characterize Cn2 using empirical models, Cn2 can be calculated more directly from Numerical Weather Prediction (NWP) simulations using pressure, temperature, thermal stability, vertical wind shear, turbulent Prandtl number, and turbulence kinetic energy (TKE). In this work we use the Weather Research and Forecast (WRF) NWP model to generate Cn2 climatologies in the planetary boundary layer and free atmosphere, allowing for both point-to-point and ground-to-space seeing estimates of the Fried Coherence length (ro) and other seeing parameters. Simulations are performed using the Maui High Performance Computing Centers (MHPCC) Mana cluster. The WRF model is configured to run at 1km horizontal resolution over a domain covering several hundreds of kilometers. The vertical resolution varies from 25 meters in the boundary layer to 500 meters in the stratosphere. The model top is 20 km. We are interested in the variations in Cn2 and the Fried Coherence Length (ro). Nearly two years of simulations have been performed over various regions

  4. Ocean feedback to tropical cyclones: Climatology and processes

    Digital Repository Service at National Institute of Oceanography (India)

    Jullien, S.; Marchesiello, P.; Menkes, C.E.; Lefevre, J.; Jourdain, N.C.; Samson, G.; Lengaigne, M.

    is not instantaneous but accumulated over time within the TC inner-core. These results thus contradict the classical evaporation-wind feedback process as being essential to intensification and rather emphasize the role of macro-scale dynamics...

  5. Eight-year Climatology of Dust Optical Depth on Mars

    CERN Document Server

    Montabone, L; Millour, E; Wilson, R J; Lewis, S R; Cantor, B A; Kass, D; Kleinboehl, A; Lemmon, M; Smith, M D; Wolff, M J

    2014-01-01

    We have produced a multiannual climatology of airborne dust from Martian year 24 to 31 using multiple datasets of retrieved or estimated column optical depths. The datasets are based on observations of the Martian atmosphere from April 1999 to July 2013 made by different orbiting instruments: the Thermal Emission Spectrometer (TES) aboard Mars Global Surveyor, the Thermal Emission Imaging System (THEMIS) aboard Mars Odyssey, and the Mars Climate Sounder (MCS) aboard Mars Reconnaissance Orbiter (MRO). The procedure we have adopted consists of gridding the available retrievals of column dust optical depth (CDOD) from TES and THEMIS nadir observations, as well as the estimates of this quantity from MCS limb observations. Our gridding method calculates averages and uncertainties on a regularly spaced, but possibly incomplete, spatio-temporal grid, using an iterative procedure weighted in space, time, and retrieval uncertainty. In order to evaluate strengths and weaknesses of the resulting gridded maps, we validat...

  6. Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Beurskens, H.J.M. [SET Analysis, Kievitlaan 26, 1742 AD Schagen (Netherlands); Brand, A.J. [Energy research Centre of the Netherlands ECN, Unit Wind Energy, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2013-02-15

    Over the years, wind energy has become a major source of renewable energy worldwide. The present chapter addresses the wind resource, which is available for exploitation for large-scale electricity production, and its specific physical properties. Furthermore, the technical options available to convert the energy of the air flow into mechanical energy and electricity are described. Specific problems of large-scale integration of wind energy into the grid as well as the present and future market developments are described in this chapter. Finally, environmental aspects are discussed briefly.

  7. Eight-year climatology of dust optical depth on Mars

    Science.gov (United States)

    Montabone, L.; Forget, F.; Millour, E.; Wilson, R. J.; Lewis, S. R.; Cantor, B.; Kass, D.; Kleinböhl, A.; Lemmon, M. T.; Smith, M. D.; Wolff, M. J.

    2015-05-01

    We have produced a multiannual climatology of airborne dust from martian year 24-31 using multiple datasets of retrieved or estimated column optical depths. The datasets are based on observations of the martian atmosphere from April 1999 to July 2013 made by different orbiting instruments: the Thermal Emission Spectrometer (TES) aboard Mars Global Surveyor, the Thermal Emission Imaging System (THEMIS) aboard Mars Odyssey, and the Mars Climate Sounder (MCS) aboard Mars Reconnaissance Orbiter (MRO). The procedure we have adopted consists of gridding the available retrievals of column dust optical depth (CDOD) from TES and THEMIS nadir observations, as well as the estimates of this quantity from MCS limb observations. Our gridding method calculates averages and uncertainties on a regularly spaced spatio-temporal grid, using an iterative procedure that is weighted in space, time, and retrieval quality. The lack of observations at certain times and locations introduces missing grid points in the maps, which therefore may result in irregularly gridded (i.e. incomplete) fields. In order to evaluate the strengths and weaknesses of the resulting gridded maps, we compare with independent observations of CDOD by PanCam cameras and Mini-TES spectrometers aboard the Mars Exploration Rovers "Spirit" and "Opportunity", by the Surface Stereo Imager aboard the Phoenix lander, and by the Compact Reconnaissance Imaging Spectrometer for Mars aboard MRO. We have statistically analyzed the irregularly gridded maps to provide an overview of the dust climatology on Mars over eight years, specifically in relation to its interseasonal and interannual variability, in addition to provide a basis for instrument intercomparison. Finally, we have produced regularly gridded maps of CDOD by spatially interpolating the irregularly gridded maps using a kriging method. These complete maps are used as dust scenarios in the Mars Climate Database (MCD) version 5, and are useful in many modeling

  8. Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

    Science.gov (United States)

    Gove, Jamison M; Williams, Gareth J; McManus, Margaret A; Heron, Scott F; Sandin, Stuart A; Vetter, Oliver J; Foley, David G

    2013-01-01

    Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will help

  9. Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

    Directory of Open Access Journals (Sweden)

    Jamison M Gove

    Full Text Available Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km from 85% of our study locations

  10. Climatological/meteorological and hydrological disasters and the insurance sector

    Directory of Open Access Journals (Sweden)

    Murat Türkeş

    2010-11-01

    Full Text Available Climate change is a continual fact during the Earth’s history. There had been many significant changes in the Earth’s climate during its evolutionary history and a lot of ecosystems had been affected by these changes. Especially the industrialization process showing rapid movement after industrial revolution has put serious pressure on the present and future climate. Human activities such as increased fossil fuel usage with the industrialization process, land-use changes, industrial processes and deforestation have increased atmospheric accumulation up of the various greenhouse gases such as carbon dioxide (CO2, methane (CH4, nitrous oxide (N2O. On the other hand, increase in frequency and severity of natural disasters can be explained mostly by the increase of the probability of extreme events due to the climate change. Increased numbers of people have been affected by climatological and meteorological catastrophes in every year. Various actions and activities such as disaster preparedness, mitigation, reduction and prevention of the impacts and early warnings are considerable with respect to the insurance sector. These activities and actions should be implemented in the frame of contemporary and comprehensive disaster management planes. Scope of the natural disaster should be expanded particularly in the countries and regions that are vulnerable to the impacts of the climate change and variability including drought events and/or natural disasters. Moreover, drought events should also be accepted as one of the severe natural disasters, and sustainable and applicable drought management plans should be developed in order to mitigate these disasters. In this context, main purpose of the study is to classify and shortly assess the climatological and meteorological disasters, and to attract attention necessity of a new disaster insurance system containing these disasters.

  11. Lightning climatology in the Congo Basin: detailed analysis

    Science.gov (United States)

    Soula, Serge; Kigotsi, Jean; Georgis, Jean-François; Barthe, Christelle

    2016-04-01

    The lightning climatology of the Congo Basin including several countries of Central Africa is analyzed in detail for the first time. It is based on World Wide Lightning Location Network (WWLLN) data for the period from 2005 to 2013. A comparison of these data with the Lightning Imaging Sensor (LIS) data for the same period shows the WWLLN detection efficiency (DE) in the region increases from about 1.70 % in the beginning of the period to 5.90 % in 2013, relative to LIS data, but not uniformly over the whole 2750 km × 2750 km area. Both the annual flash density and the number of stormy days show sharp maximum values localized in eastern of Democratic Republic of Congo (DRC) and west of Kivu Lake, regardless of the reference year and the period of the year. These maxima reach 12.86 fl km-2 and 189 days, respectively, in 2013, and correspond with a very active region located at the rear of the Virunga mountain range characterised with summits that can reach 3000 m. The presence of this range plays a role in the thunderstorm development along the year. The estimation of this local maximum of the lightning density by taking into account the DE, leads to a value consistent with that of the global climatology by Christian et al. (2003) and other authors. Thus, a mean maximum value of about 157 fl km-2 y-1 is found for the annual lightning density. The zonal distribution of the lightning flashes exhibits a maximum between 1°S and 2°S and about 56 % of the flashes located below the equator in the 10°S - 10°N interval. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, according to the reference year, in agreement with previous works in other regions of the world.

  12. Revisiting the Climatology of Atmospheric Blocking in the Northern Hemisphere

    Institute of Scientific and Technical Information of China (English)

    Ho Nam CHEUNG; ZHOU Wen; Hing Yim MOK; Man Chi WU; Yaping SHAO

    2013-01-01

    In addition to the occurrence of atmospheric blocking,the climatology of the characteristics of blocking events,including duration,intensity,and extension,in four seasons over the Northern Hemisphere was analyzed for the period 1950-2009.The seasonality and spatial variations of these characteristics were studied according to their longitudinal distributions.In general,there were sharp discrepancies in the blocking characteristics between winter and summer,and these differences were more prominent over the Atlantic and Pacific Oceans.The blocking not only occurred more frequently but also underwent stronger amplification in winter; likewise,the blocking occurred less frequently and underwent weaker amplification in summer.There are very strong interrelationships among different blocking characteristics,suggesting that they are supported by similar physical factors.In addition,the relationship between blocking over different regions and East Asian circulation was examined.Ural-Siberia is a major blocking formation region in all seasons that may exert a downstream impact on East Asia.The impact is generally weak in summer,which is due to its lower intensity and smaller duration.However,the extratropical circulation over East Asia in summer can be disturbed persistently by the frequent occurrence of blocking over the Asian continent or the Western Pacific.In particular,the blocking frequency over the Western Pacific significantly increased during the study period.This climatological information provides a background for studying the impact of blocking on East Asian circulation under both present and future climate conditions.

  13. Fun Teaching: The Key to the Future Climatology

    Science.gov (United States)

    Mulvey, G.

    2016-12-01

    In general meteorology is a science of immediate impact. What will the weather be tomorrow or next week? Climatology and climate change is the science of our long range past and future. Decisions made in the past, now, and in the future on climate change issues did and will continue to impact the global climate. It is essential that current and future generations understand the causes of climate change to make informed decisions regarding individual and government actions needed to mitigate human impacts on the future climate. The university challenge is make climatology an exciting and dynamic adventure into the past, present and future. Instructor and supporting organizations have stepped outside the "old yellow notes" approach to enable students to progress beyond remember, understand, and apply; to analyze, evaluate and create. Responding to this instructional challenge by shifting instructional techniques and tools to a new paradigm does not happen overnight. The instructional strategies to make this jump are known in general, but not in specific. This paper deals with examples of how to translate the instructional strategies into practice in ways that are fun for students and instructors. Techniques to be described include interactive discussions, debates and team challenges, such as: - Describing continental climates during past geological periods - In-class teams debates on legislature to control/modify human CO2 releases Low or no cost teaching aids such as video clips, demonstrations, specimens, and experiments will be described with outcomes and resources interest. Some examples to be discussed are - Tree cookies, cross sections - Ocean core smear slide samples of diatoms, foraminifera, etc. - Ice pack/glacial melt experiments - Glacial flow and interpreting glacial ice cores experiment - Field trips to observe geological strata and geological samples - Storytelling - the shared experiences of each instructor

  14. World Wind

    Data.gov (United States)

    National Aeronautics and Space Administration — World Wind allows any user to zoom from satellite altitude into any place on Earth, leveraging high resolution LandSat imagery and SRTM elevation data to experience...

  15. Mesoscale wind fluctuations over Danish waters

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, C.L.

    2010-12-15

    Mesoscale wind fluctuations affect the large scale integration of wind power because they undermine the day-ahead predictability of wind speed and power production, and because they can result in large fluctuations in power generation that must be balanced using reserve power. Large fluctuations in generated power are a particular problem for offshore wind farms because the typically high concentration of turbines within a limited geographical area means that fluctuations can be correlated across large numbers of turbines. Furthermore, organised mesoscale structures that often form over water, such as convective rolls and cellular convection, have length scales of tens of kilometers, and can cause large wind fluctuations on a time scale of around an hour. This thesis is an exploration of the predictability of mesoscale wind fluctuations using observations from the world's first two large offshore wind farms - Horns Rev I in the North Sea, and Nysted in the Baltic Sea. The thesis begins with a climatological analysis of wind fluctuations on time scales of 1-10 hours at the two sites. A novel method for calculating conditional climatologies of spectral information is proposed, based on binning and averaging the time axis of the Hilbert spectrum. Results reveal clear patterns between wind fluctuations and locally observed meteorological conditions. The analysis is expanded by classifying wind fluctuations on time scales of 1-3 hours according to synoptic patterns, satellite pictures and wind classes. Results indicate that cold air outbreaks and open cellular convection are a significant contributor to mesoscale wind variability at Horns Rev. The predictability of mesoscale wind fluctuations is tested by implementing standard statistical models that relate local wind variability to parameters based on a large scale weather analysis. The models show some skill, but only achieve a 15% improvement on a persistence forecast. The possibility of explicitly modelling

  16. Meso-scale wind variability. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, S.; Larsen, X.; Vincent, C.; Soerensen, P.; Pinson, P.; Trombe, P.-J.; Madsen, H.; Cutululis, N.

    2011-11-15

    The project has aimed to characterize mesoscale meteorological phenomenon for the North Sea and the Inner Danish waters, and additionally aimed on improving the predictability and quality of the power production from offshore windfarms. The meso-scale meteorology has been characterized with respect to the physical processes, climatology, spectral characteristics and correlation properties based on measurements from wind farms, satellite data (SAR) and mesoscale numerical modeling (WRF). The abilities of the WRF model to characterize and predict relevant mesoscale phenomenon has been proven. Additionally application of statistical forecasting, using a Markov switching approach that can be related to the meteorological conditions, to analyze and short term predict the power production from an offshore wind farms have been documented. Two PhD studies have been conducted in connection with the project. The project has been a cooperative project between Risoe DTU, IMM DTU, DONG Energy, Vattenfall and VESTAS. It is registered as Energinet.dk, project no. 2007-1-7141. (Author)

  17. Choice of Locations for Wind Energy Utilization With GIS Tools

    Directory of Open Access Journals (Sweden)

    Štefan Kuzevič

    2007-06-01

    Full Text Available Using of renewable energy sources, among which we can classify, wind energy, meet the requirements of environmental acceptable. The renewable energy sources have significant role in meeting the targets of Kyoto Protocol and they have very important role in the field of local and regional development and employment. Potential builder of wind plant have to take to consideration many different factors. Power of wind is one of these factors. Wind power can be estimate from measured data at the climatologically stations and airports. Choice of potential locality is by influenced many others factor, such as quantity and parameters obstacles, elevation, accessibility location for building machines, distance from connection of high voltage, etc. For examination locality we can use the GIS tools.

  18. Simulation of Sea Ice in FGOALS-g2: Climatology and Late 20th Century Changes

    Institute of Scientific and Technical Information of China (English)

    XU Shiming; SONG Mirong; LIU Jiping; WANG Bin; LI Lijuan; HUANG Wenyu; LIU Li

    2013-01-01

    Sea ice is an important component in the Earth's climate system.Coupled climate system models are indispensable tools for the study of sea ice,its internal processes,interaction with other components,and projection of future changes.This paper evaluates the simulation of sea ice by the Flexible Global Ocean-Atmosphere-Land System model Grid-point Version 2 (FGOALS-g2),in the fifth phase of the Coupled Model Inter-comparison Project (CMIP5),with a focus on historical experiments and late 20th century simulation.Through analysis,we find that FGOALS-g2 produces reasonable Arctic and Antarctic sea ice climatology and variability.Sea ice spatial distribution and seasonal change characteristics are well captured.The decrease of Arctic sea ice extent in the late 20th century is reproduced in simulations,although the decrease trend is lower compared with observations.Simulated Antarctic sea ice shows a reasonable distribution and seasonal cycle with high accordance to the amplitude of winter summer changes.Large improvement is achieved as compared with FGOALS-g1.0 in CMIP3.Diagnosis of atmospheric and oceanic forcing on sea ice reveals several shortcomings and major aspects to improve upon in the future:(1) ocean model improvements to remove the artificial island at the North Pole;(2) higher resolution of the atmosphere model for better simulation of important features such as,among others,the Icelandic Low and westerly wind over the Southern Ocean; and (3) ocean model improvements to accurately receive freshwater input from land,and higher resolution for resolving major water channels in the Canadian Arctic Archipelago.

  19. Spatially adaptive probabilistic computation of a sub-kilometre resolution lightning climatology for New Zealand

    Science.gov (United States)

    Etherington, Thomas R.; Perry, George L. W.

    2017-01-01

    Lightning is a key component of the Earth's atmosphere and climate systems, and there is a potential positive feedback between a warming climate and increased lightning activity. In the biosphere, lightning is important as the main natural ignition source for wildfires and because of its contribution to the nitrogen cycle. Therefore, it is important to develop lightning climatologies to characterise and monitor lightning activity. While traditional methods for constructing lightning climatologies are suitable for examining lightning's influence on atmospheric processes, they are less well suited for examining questions about biosphere-lightning interactions. For example, examining the interaction between lightning and wildfires requires linking atmospheric processes to finer scale terrestrial processes and patterns. Most wildfires ignited by lightning are less than one hectare in size, and so require lightning climatologies at a comparable spatial resolution. However, such high resolution lightning climatologies cannot be derived using the traditional cell-count methodology. Here we present a novel geocomputational approach for analysing lightning data at high spatial resolutions. Our approach is based on probabilistic computational methods and is capable of producing a sub-kilometre lightning climatology that honours the spatial accuracy of the strike locations and is adaptive to underlying spatial patterns. We demonstrate our methods by applying them to the mid-latitude oceanic landmass of New Zealand, an area with geographic conditions that are under-represented in existing lightning climatologies. Our resulting lightning climatology has unparalleled spatial resolution, and the spatial and temporal patterns we observe in it are consistent with other continental and tropical lightning climatologies. To encourage further use and development of our probabilistic approach, we provide Python scripts that demonstrate the method alongside our resulting New Zealand

  20. Mars climatology from Viking 1 after 20 sols

    Science.gov (United States)

    Hess, S. L.; Henry, R. M.; Greene, G. C.; Leovy, C. B.; Tillman, J. E.; Ryan, J. A.; Chamberlain, T. E.; Cole, H. L.; Dutton, R. G.; Simon, W. E.

    1976-01-01

    Results from the meteorology instruments on the Viking 1 lander are presented for the first 20 sols of operation. The daily patterns of temperature, wind, and pressure have been highly consistent during the period. Hence, these have been assembled into 20-sol composistes and analyzed harmonically. Maximum temperature was 241.8 K and minimum was 187.2 K. The composite wind vector has a mean diurnal magnitude of 2.4 meters per second with prevailing wind from the south and counterclockwise diurnal rotation. Pressure exhibits diurnal and semidiurnal oscillations. The diurnal is ascribed to a combination of effects, and the semidiurnal appears to be the solar semidiurnal tide. Similarities to earth are discussed. A major finding is a continual secular decrease in diurnal mean pressure. This is ascribed to carbon dioxide deposition at the south polar cap.

  1. Lightning Attachment to Wind Turbines in Central Kansas: Video Observations, Correlation with the NLDN and in-situ Peak Current Measurements

    Science.gov (United States)

    Myers, J.; Cummins, K. L.; Hutchinson, M.; Nag, A.

    2012-12-01

    Lightning attachment to tall objects has been studied for decades. The attachment of lightning to electric power transmission towers in elevated terrain has driven much of the quantitative assessment of lightning characteristics in the 1970's and 80's. This has led to the understanding that in flat terrain, the probability of upward-initiated lightning is negligible for tower heights less than 100 m. For tower heights greater than 100, the probability increases roughly linearly with the log of height, reaching 100% at a height of 400 m. Additionally, the probability of upward initiation increases when the object resides on locally-elevated terrain. Over the last decade, there has been renewed interest in the study of lightning attachment to tall objects in general, and wind turbines in particular, following the establishment of large "wind farms" in lightning-prone regions. In this study, we present video observations, radiation magnetic field, and in-situ peak current measurements of lightning from an ongoing field program in a large wind farm in north-central Kansas, located in the U.S. Central Great Plains. The terrain variations within the wind farm are small rolling hills with peak variations on the order of 25 m. All turbines had a turbine hub height of 80 m, and a blade tip maximum height of 125 m. Two digital video camera systems (60 fields-per-second) were configured to self-trigger 2-second video sequences using a sequential-field-subtraction scene analysis (ufo-Capture). The two cameras had a common field of view that included 8 of the wind turbines. Nearby NLDN sensors were configured to record information that allows reconstruction of magnetic field waveforms within the bandwidth of the NLDN sensors. Some of the turbines were equipped with semi-quantitative in-situ peak current measuring devices. To date, more than 100 cloud-to-ground (CG) flashes have terminated within the perimeter of the wind farm. Video observations of flashes that attached to

  2. Two methods for estimating limits to large-scale wind power generation.

    Science.gov (United States)

    Miller, Lee M; Brunsell, Nathaniel A; Mechem, David B; Gans, Fabian; Monaghan, Andrew J; Vautard, Robert; Keith, David W; Kleidon, Axel

    2015-09-08

    Wind turbines remove kinetic energy from the atmospheric flow, which reduces wind speeds and limits generation rates of large wind farms. These interactions can be approximated using a vertical kinetic energy (VKE) flux method, which predicts that the maximum power generation potential is 26% of the instantaneous downward transport of kinetic energy using the preturbine climatology. We compare the energy flux method to the Weather Research and Forecasting (WRF) regional atmospheric model equipped with a wind turbine parameterization over a 10(5) km2 region in the central United States. The WRF simulations yield a maximum generation of 1.1 We⋅m(-2), whereas the VKE method predicts the time series while underestimating the maximum generation rate by about 50%. Because VKE derives the generation limit from the preturbine climatology, potential changes in the vertical kinetic energy flux from the free atmosphere are not considered. Such changes are important at night when WRF estimates are about twice the VKE value because wind turbines interact with the decoupled nocturnal low-level jet in this region. Daytime estimates agree better to 20% because the wind turbines induce comparatively small changes to the downward kinetic energy flux. This combination of downward transport limits and wind speed reductions explains why large-scale wind power generation in windy regions is limited to about 1 We⋅m(-2), with VKE capturing this combination in a comparatively simple way.

  3. Assessing a 1500-year record of Atlantic hurricane activity from South Andros Island, the Bahamas, using modeled hurricane climatology

    Science.gov (United States)

    Wallace, E. J.; Donnelly, J. P.; Emanuel, K.; Wiman, C.; van Hengstum, P. J.; Sullivan, R.; Winkler, T. S.

    2016-12-01

    Tropical cyclones can cause substantial loss of life and economic resources in coastal areas. In the current changing climate, it is of critical importance for society to understand any links between hurricane activity and climactic conditions. Unfortunately, historical tropical cyclone records are too short and incomplete to constrain how climate controls cyclone activity or to accurately quantify the risk of such storms to local human populations. Hurricane-induced deposits preserved in sediment cores can offer records of past hurricane activity stretching over thousands of years. Here we present a 1500 year annually resolved record of the frequency of intense hurricane events in a blue hole (AM4) on South Andros Island on the Great Bahama Bank. This carbonate island in the western North Atlantic Ocean is positioned along the trackway of many storms originating in the Caribbean and Atlantic basins. The record is corroborated by cores collected from three other blue holes near AM4. Over the past 1500 years, there have been periods of elevated hurricane activity from 750 to 950 CE, 1150 to 1300 CE and 1550 to 1850 CE. The statistical significance of this sedimentary record is assessed utilizing a set of synthetic storms generated from a previously published statistical deterministic hurricane model. The model simulates climatological conditions from the NCEP/NCAR reanalysis dataset, and the CMIP5 MPI model for the 20th century calibration (1850-2005 CE), and the millennial simulation (850-1849 CE). The average reoccurrence rates of hurricanes passing within 100 km of AM4 under each simulation are 1.06, 0.62, and 0.61 storms per year respectively. Using each climatology, thousands of hurricane induced deposits for the site are generated based on a random draw of these storms, a wind speed threshold for deposit, and a temporal resolution given the sedimentation rate of approximately 1 cm/yr at the site. Overall, the results of this study offer information on changes

  4. Climatology of damage-causing hailstorms over Germany

    Science.gov (United States)

    Kunz, M.; Puskeiler, M.; Schmidberger, M.

    2012-04-01

    In several regions of Central Europe, such as southern Germany, Austria, Switzerland, and northern Italy, hailstorms often cause substantial damage to buildings, crops, or automobiles on the order of several million EUR. In the federal state of Baden-Württemberg, for example, most of the insured damage to buildings is caused by large hailstones. Due to both their local-scale extent and insufficient direct monitoring systems, hail swaths are not captured accurately and uniquely by a single observation system. Remote-sensing systems such as radars are able to detect convection signals in a basic way, but they lack the ability to discern a clear relation between measured intensity and hail on the ground. These shortcomings hamper statistical analysis on the hail probability and intensity. Hail modelling thus is a big challenge for the insurance industry. Within the project HARIS-CC (Hail Risk and Climate Change), different meteorological observations are combined (3D / 2D radar, lightning, satellite and radiosounding data) to obtain a comprehensive picture of the hail climatology over Germany. The various approaches were tested and calibrated with loss data from different insurance companies between 2005 and 2011. Best results are obtained by considering the vertical distance between the 0°C level of the atmosphere and the echo top height estimated from 3D reflectivity data from the radar network of German Weather Service (DWD). Additionally, frequency, intensity, width, and length of hail swaths are determined by applying a cell tracking algorithm to the 3D radar data (TRACE3D; Handwerker, 2002). The hailstorm tracks identified are merged with loss data using a geographical information system (GIS) to verify damage-causing hail on the ground. Evaluating the hailstorm climatology revealed that hail probability exhibits high spatial variability even over short distances. An important issue is the spatial pattern of hail occurrence that is considered to be due to

  5. A Precipitation Climatology of the Snowy Mountains, Australia

    Science.gov (United States)

    Theobald, Alison; McGowan, Hamish; Speirs, Johanna

    2014-05-01

    The precipitation that falls in the Snowy Mountains region of southeastern Australia provides critical water resources for hydroelectric power generation. Water storages in this region are also a major source of agricultural irrigation, environmental flows, and offer a degree of flood protection for some of the major river systems in Australia. Despite this importance, there remains a knowledge gap regarding the long-term, historic variability of the synoptic weather systems that deliver precipitation to the region. This research aims to increase the understanding of long-term variations in precipitation-bearing weather systems resulting in runoff into the Snowy Mountains catchments and reservoirs, and the way in which these are influenced by large-scale climate drivers. Here we present initial results on the development of a climatology of precipitation-bearing synoptic weather systems (synoptic typology), spanning a period of over 100 years. The synoptic typology is developed from the numerical weather model re-analysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF), in conjunction with regional precipitation and temperature data from a network of private gauges. Given the importance of surface, mid- and upper-air patterns on seasonal precipitation, the synoptic typing will be based on a range of meteorological variables throughout the depth of the troposphere, highlighting the importance of different atmospheric levels on the development and steering of synoptic precipitation bearing systems. The temporal and spatial variability of these synoptic systems, their response to teleconnection forcings and their contribution to inflow generation in the headwater catchments of the Snowy Mountains will be investigated. The resulting climatology will provide new understanding of the drivers of regional-scale precipitation variability at inter- and intra-annual timescales. It will enable greater understanding of how variability in synoptic scale

  6. Climatological context for large-scale coral bleaching

    Science.gov (United States)

    Barton, A. D.; Casey, K. S.

    2005-12-01

    Large-scale coral bleaching was first observed in 1979 and has occurred throughout virtually all of the tropics since that time. Severe bleaching may result in the loss of live coral and in a decline of the integrity of the impacted coral reef ecosystem. Despite the extensive scientific research and increased public awareness of coral bleaching, uncertainties remain about the past and future of large-scale coral bleaching. In order to reduce these uncertainties and place large-scale coral bleaching in the longer-term climatological context, specific criteria and methods for using historical sea surface temperature (SST) data to examine coral bleaching-related thermal conditions are proposed by analyzing three, 132 year SST reconstructions: ERSST, HadISST1, and GISST2.3b. These methodologies are applied to case studies at Discovery Bay, Jamaica (77.27°W, 18.45°N), Sombrero Reef, Florida, USA (81.11°W, 24.63°N), Academy Bay, Galápagos, Ecuador (90.31°W, 0.74°S), Pearl and Hermes Reef, Northwest Hawaiian Islands, USA (175.83°W, 27.83°N), Midway Island, Northwest Hawaiian Islands, USA (177.37°W, 28.25°N), Davies Reef, Australia (147.68°E, 18.83°S), and North Male Atoll, Maldives (73.35°E, 4.70°N). The results of this study show that (1) The historical SST data provide a useful long-term record of thermal conditions in reef ecosystems, giving important insight into the thermal history of coral reefs and (2) While coral bleaching and anomalously warm SSTs have occurred over much of the world in recent decades, case studies in the Caribbean, Northwest Hawaiian Islands, and parts of other regions such as the Great Barrier Reef exhibited SST conditions and cumulative thermal stress prior to 1979 that were comparable to those conditions observed during the strong, frequent coral bleaching events since 1979. This climatological context and knowledge of past environmental conditions in reef ecosystems may foster a better understanding of how coral reefs will

  7. Predictability and Diagnostics of Western Himalayan Hydro-climatology

    Science.gov (United States)

    Pal, I.; Lall, U.; Robertson, A. W.; Cane, M. A.

    2011-12-01

    Snowmelt dominated streamflow of the Western Himalayan rivers is an important water resource during the dry pre-monsoon months to meet the irrigation and hydropower needs in northern India. On the other hand, winter precipitation as the form of snow over Himalayas helps in maintaining the glaciers, which serve as a storehouse of freshwater throughout the year. With the help of the hydro-climatological data provided by the Bhakra Beas Management Board in India, we present the outcome of our research on the prediction and diagnostics of Satluj river basin hydro-climatology at the Indian side up to the upstream of Bhakra dam, which is a major source of water for irrigation and electricity generation (1325MW) for north India. Spring seasonal inflow anomalies to Bhakra dam are strongly correlated with large-scale precipitation and temperature in the preceding winter over the Western Himalayas and adjoining north and central Indian plains, suggesting a potentially usable predictability for reservoir managers. Winter precipitation in the Western Himalayas is mainly brought about by the mid-latitude jet stream leading to the formation of low-pressure synoptic systems known as Western Disturbances (WD). WDs originate over the North Atlantic Ocean or Mediterranean Sea, with secondaries developing over the Persian Gulf and Caspian Sea either directly or as a result of the arrival of low-pressure systems from southwest Arabia, and travel eastward over Iran, Afghanistan, Pakistan, and northwest India. Winter WDs (and therefore the average volume of winter precipitation over Western Himalayas) are also modulated by the large-scale interaction between ocean and atmosphere led by the variation of the SSTs of the Indian Ocean and Pacific. As a result, average spring inflow volume, which is a function of the average volume of precipitation in winter, was also found to be positively correlated with the SSTs over the western and equatorial Indian Ocean, and with below-normal sea

  8. Wind Loads on Structures

    DEFF Research Database (Denmark)

    Dyrbye, Claes; Hansen, Svend Ole

    pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations......Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...

  9. Wind Loads on Structures

    DEFF Research Database (Denmark)

    Dyrbye, Claes; Hansen, Svend Ole

    pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations......Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...

  10. Wind Generators

    Science.gov (United States)

    1989-01-01

    When Enerpro, Inc. president, Frank J. Bourbeau, attempted to file a patent on a system for synchronizing a wind generator to the electric utility grid, he discovered Marshall Space Flight Center's Frank Nola's power factor controller. Bourbeau advanced the technology and received a NASA license and a patent for his Auto Synchronous Controller (ASC). The ASC reduces generator "inrush current," which occurs when large generators are abruptly brought on line. It controls voltage so the generator is smoothly connected to the utility grid when it reaches its synchronous speed, protecting the components from inrush current damage. Generator efficiency is also increased in light winds by applying lower than rated voltage. Wind energy is utilized to drive turbines to generate electricity for utility companies.

  11. Satellite Regional Cloud Climatology over the Great Lakes

    Directory of Open Access Journals (Sweden)

    Steven A. Ackerman

    2013-11-01

    Full Text Available Thirty-one years of imager data from polar orbiting satellites are composited to produce a satellite climate data set of cloud amount for the Great Lakes region. A trend analysis indicates a slight decreasing trend in cloud cover over the region during this time period. The trend is significant and largest (~2% per decade over the water bodies. A strong seasonal cycle of cloud cover is observed over both land and water surfaces. Winter cloud amounts are greater over the water bodies than land due to heat and moisture flux into the atmosphere. Late spring through early autumn cloud amounts are lower over the water bodies than land due to stabilization of the boundary layer by relatively cooler lake waters. The influence of the lakes on cloud cover also extends beyond their shores, affecting cloud cover and properties far down wind. Cloud amount composited by wind direction demonstrate that the increasing cloud amounts downwind of the lakes is greatest during autumn and winter. Cold air flows over relatively warm lakes in autumn and winter generate wind parallel convective cloud bands. The cloud properties of these wind parallel cloud bands over the lakes during winter are presented.

  12. WRF Mesoscale Pre-Run for the Wind Atlas of Mexico

    DEFF Research Database (Denmark)

    Hahmann, Andrea N.; Pena Diaz, Alfredo; Hansen, Jens Carsten

    This report documents the work performed by DTU Wind Energy for the project “Atlas Eólico Mexicano” or the Wind Atlas of Mexico. This document reports on the methods used in “Pre-run” of the windmapping project for Mexico. The interim mesoscale modeling results were calculated from the output...... of simulations using the Weather, Research and Forecasting (WRF) model. We document the method used to run the mesoscale simulations and to generalize the WRF model wind climatologies. A separate section covers the preliminary validation of the WRF simulations against tall mast observations....

  13. Towards more accurate wind and solar power prediction by improving NWP model physics

    Science.gov (United States)

    Steiner, Andrea; Köhler, Carmen; von Schumann, Jonas; Ritter, Bodo

    2014-05-01

    nighttime to well mixed conditions during the day presents a big challenge to NWP models. Fast decrease and successive increase in hub-height wind speed after sunrise, and the formation of nocturnal low level jets will be discussed. For PV, the life cycle of low stratus clouds and fog is crucial. Capturing these processes correctly depends on the accurate simulation of diffusion or vertical momentum transport and the interaction with other atmospheric and soil processes within the numerical weather model. Results from Single Column Model simulations and 3d case studies will be presented. Emphasis is placed on wind forecasts; however, some references to highlights concerning the PV-developments will also be given. *) ORKA: Optimierung von Ensembleprognosen regenerativer Einspeisung für den Kürzestfristbereich am Anwendungsbeispiel der Netzsicherheitsrechnungen **) EWeLiNE: Erstellung innovativer Wetter- und Leistungsprognosemodelle für die Netzintegration wetterabhängiger Energieträger, www.projekt-eweline.de

  14. Temporal and Spatial Changes in Northern Hemisphere Floating Climatological Seasons

    Science.gov (United States)

    Choi, G.; Robinson, D. A.

    2007-12-01

    Floating climatological seasons, for which onsets and durations vary temporally and spatially, are examined over Northern Hemisphere continents and oceans. Among the variables evaluated are surface air temperature, snow extent, vegetation greenness, and atmospheric carbon dioxide concentrations. Seasonal thresholds are defined for each variable (e.g. daily mean temperature exceeding 5°C (20°C) to mark the beginning of spring (summer)). The dates on which these thresholds are reached at a given location are determined for each year over the past three decades. These seasonal onsets and offsets "float" temporally and spatially from year to another. An analysis of floating dates finds that winter duration has shortened in Europe, eastern Asia, and western North America, primarily due to an earlier spring onset. The spatial pattern of this earlier onset is associated with a positive Arctic Oscillation (AO) regime in the previous winter months. The positive winter AO finds anomalously high pressure sitting in the middle latitudes in locations where spring arrives early. This is likely due to a combination of advective fluxes of warmth and moisture and the local enhancement of solar radiation reaching the surface under clear skies. This, in turn, promotes earlier snow melt that further enhances warming and an earlier green-up. Extended summer duration is observed over continents and oceans (except the Arctic Ocean, where summer does not exist). The oceanic zone along 30°N has experienced a particularly large increase in duration, suggesting Hadley cell expansion.

  15. Borneo Vortices: A case study and its relation to climatology

    Science.gov (United States)

    Braesicke, P.; Ooi, S. H.; Samah, A. A.

    2012-04-01

    Borneo vortices (BVs) develop over the South China Sea and are main drivers for the formation of deep convection and heavy rainfall in East Malaysia. We present a case study of a cold-surge-induced BV during January 2010 in which the export of potential energy lead to a strengthening of the subtropical jet. Potential vorticity (PV) and water vapour analyses confirm a significant impact of the BV on upper tropospheric composition. Dry, high PV air is found far below 100 hPa in the vicinty of the vortex. Using a PV threshold analysis of ERA-Interim data we construct a climatological composite of similar events and characterise the thermal, dynamical and composition structure of a 'typical' BV. We note the preferential formation of BVs during ENSO cold conditions and show that two effects contribute to the formation of the dry upper layer above a BV: Air is vertically transported upwards in the BV whilst precipitating and the large scale flow in which the BV is embedded advect dry, ozone rich air from the equatorial TTL over the BV. Thus the occurence frequency of BVs is important for the regional variability of upper tropospheric/lower stratospheric composition.

  16. Climatology characterization of equatorial plasma bubbles using GPS data

    Science.gov (United States)

    Magdaleno, Sergio; Herraiz, Miguel; Altadill, David; de la Morena, Benito A.

    2017-01-01

    The climatology of equatorial plasma bubbles (EPBs) for the period 1998-2008 was studied using slant total electron content (sTEC) derived from global positioning system (GPS) data. The sTEC values were calculated from data measured at 67 International GNSS Service (IGS) stations distributed worldwide around the geomagnetic equator and embracing the region of the ionospheric equatorial anomaly (IEA). EPBs and their characteristics were obtained using the Ionospheric Bubble Seeker (IBS) application, which detects and distinguishes sTEC depletions associated with EPBs. This technique bases its analysis on the time variation of the sTEC and on the population variance of this time variation. IBS finds an EPB by default when an sTEC depletion is greater than 5 TEC units (TECu). The analysis of the spatial behavior shows that the largest rate of EPB takes place at the equator and in the South America-Africa sector, while their occurrence decreases as the distance from the magnetic equator increases. The depth and duration of the sTEC depletions also maximize at the equator and in the South America-Africa sector and weaken departing from the equator. The results of the temporal analysis for the data of the IGS stations located in AREQ, NKLG, IISC, and GUAM indicate that the greatest rate of EPB occurrence is observed for high solar activity.

  17. Climatology characterization of equatorial plasma bubbles using GPS data

    Directory of Open Access Journals (Sweden)

    Magdaleno Sergio

    2017-01-01

    Full Text Available The climatology of equatorial plasma bubbles (EPBs for the period 1998–2008 was studied using slant total electron content (sTEC derived from global positioning system (GPS data. The sTEC values were calculated from data measured at 67 International GNSS Service (IGS stations distributed worldwide around the geomagnetic equator and embracing the region of the ionospheric equatorial anomaly (IEA. EPBs and their characteristics were obtained using the Ionospheric Bubble Seeker (IBS application, which detects and distinguishes sTEC depletions associated with EPBs. This technique bases its analysis on the time variation of the sTEC and on the population variance of this time variation. IBS finds an EPB by default when an sTEC depletion is greater than 5 TEC units (TECu. The analysis of the spatial behavior shows that the largest rate of EPB takes place at the equator and in the South America-Africa sector, while their occurrence decreases as the distance from the magnetic equator increases. The depth and duration of the sTEC depletions also maximize at the equator and in the South America-Africa sector and weaken departing from the equator. The results of the temporal analysis for the data of the IGS stations located in AREQ, NKLG, IISC, and GUAM indicate that the greatest rate of EPB occurrence is observed for high solar activity.

  18. Site insolation and wind power characteristics. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    Bray, R E

    1980-08-01

    Design and operation of either large or small scale solar and wind energy conversion systems should be based, in part, on knowledge of expected solar and wind power trends. For this purpose, historic solar and wind data available at 101 National Weather Service stations were processed statistically. Preliminary planning data are provided for selected daily average solar and wind power conditions occurring and persisting for time periods of interest. Solar data are global radiation incident on a horizontal surface, and wind data represent wind power normal to the air flow. Empirical probabilities were constructed from the historic data to provide a reasonable inference of the chance of similar climatological conditions occurring at any given time in the future. (Diurnal wind power variations were also considered.) Ratios were also generated at each station to relate the global radiation data to insolation on a south-facing surface inclined at various angles. In addition, joint probability distributions were derived to show the proportion of days with solar and wind power within selected intervals.

  19. West African equatorial ionospheric parameters climatology based on Ouagadougou ionosonde station data from June 1966 to February 1998

    Directory of Open Access Journals (Sweden)

    F. Ouattara

    2009-06-01

    Full Text Available This study is the first which gives the climatology of West African equatorial ionosphere by using Ouagadougou station through three solar cycles. It has permitted to show the complete morphology of ionosphere parameters by analyzing yearly variation, solar cycle and geomagnetic activity, seasonal evolution and diurnal development. This work shows that almost all ionospheric parameters have 11-year solar cycle evolution. Seasonal variation shows that only foF2 exhibits annual, winter and semiannual anomaly. foF2 seasonal variation has permitted us to identify and characterize solar events effects on F2 layer in this area. In fact (1 during quiet geomagnetic condition foF2 presents winter and semiannual anomalies asymmetric peaks in March/April and October. (2 The absence of winter anomaly and the presence of equinoctial peaks are the most visible effects of fluctuating activity in foF2 seasonal time profiles. (3 Solar wind shock activity does not modify the profile of foF2 but increases ionization. (4 The absence of asymmetry peaks, the location of the peaks in March and October and the increase of ionization characterize recurrent storm activity. F1 layers shows increasing trend from cycle 20 to cycle 21. Moreover, E layer parameters seasonal variations exhibit complex structure. It seems impossible to detect fluctuating activity effect in E layer parameters seasonal variations but shock activity and wind stream activity act to decrease E layer ionization. It can be seen from Es layer parameters seasonal variations that wind stream activity effect is fairly independent of solar cycle. E and Es layers critical frequencies and virtual heights diurnal variations let us see the effects of the greenhouse gases in these layers.

  20. Climatology of diurnal tide and its long-term variability in the lower middle atmosphere over a tropical station

    Science.gov (United States)

    Kumar, P. Vinay; Dutta, Gopa; Mohammad, Salauddin; Rao, B. Venkateswara

    2016-07-01

    ECMWF reanalysis (ERA-interim) data of winds for two solar cycles (1991-2012) are harmonically analyzed to delineate the characteristics and variability of diurnal tide over a tropical site (13.5° N, 79.5° E). The diurnal cycle horizontal winds measured by Gadanki (13.5° N, 79.2° E) mesosphere-stratosphere-troposphere (MST) radar between May 2005 and April 2006 have been used to compute 24 h tidal amplitudes and phases and compared with the corresponding results obtained from ERA winds. The climatological diurnal tidal amplitudes and phases have been estimated from surface to ˜33 km using ERA interim data. The amplitudes and phases obtained in the present study are found to compare reasonably well with Global Scale Wave Model (GSWM-09). Diurnal tides show larger amplitudes in the lower troposphere below 5 km during summer and in the mid-stratosphere mainly during equinoctial months and early winter. Water vapor and convection in the lower troposphere are observed to play major roles in exciting 24-h tide. Correlations between diurnal amplitude and integrated water vapor and between diurnal amplitude and outgoing longwave radiation (OLR) are 0.59 and -0.34, respectively. Ozone mixing ratio correlates (ρ = 0.66) well with diurnal amplitude and shows annual variation in the troposphere whereas semi-annual variation is observed at stratospheric heights with stronger peaks in equinoctial months. A clear annual variation of diurnal amplitude is displayed in the troposphere and interannual variability becomes prominent in the stratosphere which could be partly due to the influence of equatorial stratospheric QBO. The influence of solar activity on diurnal oscillations is found to be insignificant.

  1. Remote Sensing Wind and Wind Shear System.

    Science.gov (United States)

    Contents: Remote sensing of wind shear and the theory and development of acoustic doppler; Wind studies; A comparison of methods for the remote detection of winds in the airport environment; Acoustic doppler system development; System calibration; Airport operational tests.

  2. East Asian Seas Regional Climatology Version 2.0 from 1804 to 2014 (NODC Accession 0123300)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The East Asian Seas Regional Climatology Version 2.0 is an update to the preliminary version released in May 2012. This update includes new temperature and salinity...

  3. SST Anomaly, NOAA POES AVHRR, Casey and Cornillon Climatology, 0.1 degrees, Global

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes SST anomaly data using a combination of the POES AVHRR Global Area Coverage data, and data from a climatological database by Casey and...

  4. Monthly Summaries of the Global Historical Climatology Network - Daily (GHCN-D)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly Summaries of Global Historical Climatology Network (GHCN)-Daily is a dataset derived from GHCN-Daily. The data are produced by computing simple averages or...

  5. SST Anomaly, NOAA POES AVHRR, Casey and Cornillon Climatology, 0.1 degrees, Global

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes SST anomaly data using a combination of the POES AVHRR Global Area Coverage data, and data from a climatological database by Casey and...

  6. Extending and Merging the Purple Crow Lidar Temperature Climatologies Using the Inversion Method

    Science.gov (United States)

    Jalali, Ali; Sica, R. J.; Argall, P. S.

    2016-06-01

    Rayleigh and Raman scatter measurements from The University of Western Ontario Purple Crow Lidar (PCL) have been used to develop temperature climatologies for the stratosphere, mesosphere, and thermosphere using data from 1994 to 2013 (Rayleigh system) and from 1999 to 2013 (vibrational Raman system). Temperature retrievals from Rayleigh-scattering lidar measurements have been performed using the methods by Hauchecorne and Chanin (1980; henceforth HC) and Khanna et al. (2012). Argall and Sica (2007) used the HC method to compute a climatology of the PCL measurements from 1994 to 2004 for 35 to 110 km, while Iserhienrhien et al. (2013) applied the same technique from 1999 to 2007 for 10 to 35 km. Khanna et al. (2012) used the inversion technique to retrieve atmospheric temperature profiles and found that it had advantages over the HC method. This paper presents an extension of the PCL climatologies created by Argall and Sica (2007) and Iserhienrhien et al. (2013). Both the inversion and HC methods were used to form the Rayleigh climatology, while only the latter was adopted for the Raman climatology. Then, two different approaches were used to merge the climatologies from 10 to 110 km. Among four different functional identities, a trigonometric hyperbolic relation results in the best choice for merging temperature profiles between the Raman and Low level Rayleigh channels, with an estimated uncertainty of 0.9 K for merging temperatures. Also, error function produces best result with uncertainty of 0.7 K between the Low Level Rayleigh and High Level Rayleigh channels. The results show that the temperature climatologies produced by the HC method when using a seed pressure are comparable to the climatologies produced by the inversion method. The Rayleigh extended climatology is slightly warmer below 80 km and slightly colder above 80 km. There are no significant differences in temperature between the extended and the previous Raman channel climatologies. Through out

  7. Extending and Merging the Purple Crow Lidar Temperature Climatologies Using the Inversion Method

    Directory of Open Access Journals (Sweden)

    Jalali Ali

    2016-01-01

    Full Text Available Rayleigh and Raman scatter measurements from The University of Western Ontario Purple Crow Lidar (PCL have been used to develop temperature climatologies for the stratosphere, mesosphere, and thermosphere using data from 1994 to 2013 (Rayleigh system and from 1999 to 2013 (vibrational Raman system. Temperature retrievals from Rayleigh-scattering lidar measurements have been performed using the methods by Hauchecorne and Chanin (1980; henceforth HC and Khanna et al. (2012. Argall and Sica (2007 used the HC method to compute a climatology of the PCL measurements from 1994 to 2004 for 35 to 110 km, while Iserhienrhien et al. (2013 applied the same technique from 1999 to 2007 for 10 to 35 km. Khanna et al. (2012 used the inversion technique to retrieve atmospheric temperature profiles and found that it had advantages over the HC method. This paper presents an extension of the PCL climatologies created by Argall and Sica (2007 and Iserhienrhien et al. (2013. Both the inversion and HC methods were used to form the Rayleigh climatology, while only the latter was adopted for the Raman climatology. Then, two different approaches were used to merge the climatologies from 10 to 110 km. Among four different functional identities, a trigonometric hyperbolic relation results in the best choice for merging temperature profiles between the Raman and Low level Rayleigh channels, with an estimated uncertainty of 0.9 K for merging temperatures. Also, error function produces best result with uncertainty of 0.7 K between the Low Level Rayleigh and High Level Rayleigh channels. The results show that the temperature climatologies produced by the HC method when using a seed pressure are comparable to the climatologies produced by the inversion method. The Rayleigh extended climatology is slightly warmer below 80 km and slightly colder above 80 km. There are no significant differences in temperature between the extended and the previous Raman channel climatologies

  8. Technical Description Lillgrund Wind Power Plant. Lillgrund Pilot Project

    Energy Technology Data Exchange (ETDEWEB)

    Jeppsson, Joakim; Larsen, Poul Erik; Larsson, Aake (Vattenfall Vindkraft AB, Stockholm (Sweden))

    2008-09-15

    Lillgrund offshore wind power plant comprises 48 wind turbines, each rated at 2.3 MW, bringing the total wind farm capacity to 110 MW. The Lillgrund offshore wind power plant is located in a shallow area of Oeresund, 7 km off the coast of Sweden and 7 km south from the Oeresund Bridge connecting Sweden and Denmark. An average wind speed of around 8,5 m/s at hub height, combined with a relatively low water depth of 4 to 8 meters makes it economically feasible to build here. Vattenfall Vindkraft AB is the owner and operator of Lillgrund offshore wind power plant. Lillgrund is a Swedish pilot project supported by the Swedish Energy Agency. The bidding process was completed during 2005 and the offshore power plant was constructed in the period 2006 to 2007. The wind farm was constructed on time and has now been successfully operational since December 2007. There is, however, always potential for improvement and the aim of this report has been to determine and highlight these areas. It is worth noting out that only the electrical system and the foundations are tailor made at offshore wind power plants. The wind turbines are more or less standard products with none or very limited possibilities for project specific design changes. Geotechnical investigations are expensive and it can be difficult to balance the risks as well as the benefits of this expense in the early phases of a large infrastructure project. As a whole, the geotechnical surveys at Lillgrund proved to be useful. They identified potential issues, such as the fact that extra excavation was required for two of the foundations. It also revealed the location of a small number of boulders that would have to be removed. Vattenfall requested a complete study of the electrical system for Lillgrund to be delivered with the bids. That request was not met. Instead Siemens Wind Power began a complete electrical system study after being awarded the Contract. The electrical system study was completed during the

  9. Formation and Development of Diabatic Rossby Vortices in a 10-Year Climatology

    Science.gov (United States)

    2012-06-01

    DEVELOPMENT OF DIABATIC ROSSBY VORTICES IN A 10-YEAR CLIMATOLOGY by Nengwei “Tom” Shih June 2012 Thesis Advisor: Richard W. Moore Second...TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Formation and Development of Diabatic Rossby Vortices in a 10-Year Climatology 5...release; distribution is unlimited 12b. DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) A diabatic Rossby vortex (DRV) is a short-scale

  10. Wind Energy Japan

    Energy Technology Data Exchange (ETDEWEB)

    Komatsubara, Kazuyo [Embassy of the Kingdom of the Netherlands, Tokyo (Japan)

    2012-06-15

    An overview is given of wind energy in Japan: Background; Wind Energy in Japan; Japanese Wind Energy Industry; Government Supports; Useful Links; Major Japanese Companies; Profiles of Major Japanese Companies; Major Wind Energy Projects in Japan.

  11. Are local wind power resources well estimated?

    Science.gov (United States)

    Lundtang Petersen, Erik; Troen, Ib; Jørgensen, Hans E.; Mann, Jakob

    2013-03-01

    project is structured around three areas of work, to be implemented in parallel. Creation and publication of a European wind atlas in electronic form [2], which will include the underlying data and a new EU wind climate database which will as a minimum include: wind resources and their associated uncertainty; extreme wind and uncertainty; turbulence characteristics; adverse weather conditions such as heavy icing, electrical storms and so on together with the probability of occurrence; the level of predictability for short-term forecasting and assessment of uncertainties; guidelines and best practices for the use of data especially for micro-siting. Development of dynamical downscaling methodologies and open-source models validated through measurement campaigns, to enable the provision of accurate wind resource and external wind load climatology and short-term prediction at high spatial resolution and covering Europe. The developed downscaling methodologies and models will be fully documented and made publicly available and will be used to produce overview maps of wind resources and other relevant data at several heights and at high horizontal resolution. Measurement campaigns to validate the model chain used in the wind atlas. At least five coordinated measurement campaigns will be undertaken and will cover complex terrains (mountains and forests), offshore, large changes in surface characteristics (roughness change) and cold climates. One of the great challenges to the project is the application of mesoscale models for wind resource calculation, which is by no means a simple matter [3]. The project will use global reanalysis data as boundary conditions. These datasets, which are time series of the large-scale meteorological situation covering decades, have been created by assimilation of measurement data from around the globe in a dynamical consistent fashion using large-scale numerical models. For wind energy, the application of the reanalysis datasets is as a long

  12. Wind Power Curve Modeling Using Statistical Models: An Investigation of Atmospheric Input Variables at a Flat and Complex Terrain Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Irons, Z. [Enel Green Power North America, Andover, MA (United States); Qualley, G. [Infigen Energy, Dallas, TX (United States); Newman, J. F. [Univ. of Oklahoma, Norman, OK (United States); Miller, W. O. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-28

    The goal of our FY15 project was to explore the use of statistical models and high-resolution atmospheric input data to develop more accurate prediction models for turbine power generation. We modeled power for two operational wind farms in two regions of the country. The first site is a 235 MW wind farm in Northern Oklahoma with 140 GE 1.68 turbines. Our second site is a 38 MW wind farm in the Altamont Pass Region of Northern California with 38 Mitsubishi 1 MW turbines. The farms are very different in topography, climatology, and turbine technology; however, both occupy high wind resource areas in the U.S. and are representative of typical wind farms found in their respective areas.

  13. Climatological analysis of precipitation patterns over Mount Baldo (Southern Alps)

    Science.gov (United States)

    Poletti, G.; Zardi, D.; de Franceschi, M.

    2010-09-01

    The mountain range of Mount Baldo is an elongated chain in the southern Prealps. Bounded on the western side by Lake Garda, and on the eastern side by the parallel-running deep furrow of the River Adige Valley, the whole Mount Baldo range stretches in the direction southwest-northeast for about 40 km, from the southern highlands of Caprino Veronese up to the elevated saddle joining the surroundings of Rovereto (in the Adige Valley) to the plain of Nago-Torbole (northern shore of Lake Garda). Mount Baldo displays for most of its length a sharp and uninterrupted crest ridge, mostly running over 2000 m MSL. Its surface covers a variety of altitudinal ranges, from 65 m MSL at the mountain feet, along the Lake Garda shores, to 2,218 m MSL at its highest peak (Cima Valdritta). Furthermore the particular layout of being the southernmost alpine headland, projecting as a balcony over the Po Plain, makes it exposed to the climatic influence of the larger Mediterranean basin. All of these factors concurred to develop a remarkable variety of local microclimates, geographical characters and ecosystems. In particular Mount Baldo is well known for its varied flora, whence it has been named, since 16th century, Hortus Europae (Europe Garden). Precipitation is one of the key factors characterising the peculiar local climates of Mount Baldo. Various precipitation features can be produced by a variety of processes, including both orographic uplift of moist air advected by synoptic systems, and evaporation and up-slope advection of moist air from Lake Garda or from the Po Plain. Furthermore these effects may variously develop, and even combine, under different meteorological scenarios. In the present contribution the preliminary results are shown from a research work aiming at retrieving, collecting in a homogeneous dataset and analysing data from 18 weather stations disseminated on Mount Baldo, in order to produce a climatological analysis of precipitation in the area. The whole

  14. Chemical climatology of the southeastern United States, 1999–2013

    Directory of Open Access Journals (Sweden)

    G. M. Hidy

    2014-06-01

    Full Text Available A series of experiments (the Southern Oxidant and Aerosol Study-SOAS took place in central Alabama in June–July 2013 as part of the broader Southern Atmosphere Study (SAS. These projects were aimed at studying oxidant photochemistry and formation and impacts of aerosols at a detailed process level in a location where high biogenic organic vapor emissions interact with anthropogenic emissions, and the atmospheric chemistry occurs in a subtropical climate in North America. The majority of the ground-based experiments were located at the Southeastern Aerosol Research and Characterization (SEARCH Centreville (CTR site near Brent, Alabama, where extensive, unique aerometric measurements of meteorology, trace gases and particles have been made from the early 1990s through 2013. The SEARCH network data permits a characterization of temporal and spatial context of the SOAS findings. The long-term measurements show that the SOAS experiments took place during the second wettest and coolest year in the 2000–2013 period, with lower than average solar radiation. The pollution levels at CTR and other SEARCH sites were the lowest since full measurements began in 1999. This dataset provides a perspective for the SOAS program in terms of long-term average chemistry (chemical climatology and short-term comparisons of summer average spatial variability across the Southeast at high temporal (hourly resolution. Changes in anthropogenic gas and particle emissions between 1999 and 2013, account for the decline in pollutant concentrations at the monitoring sites in the region. The long-term and short-term data provide an opportunity to contrast SOAS results with temporally and spatially variable conditions in support for the development of tests for the robustness of SOAS findings.

  15. A climatology of formation conditions for aerodynamic contrails

    Directory of Open Access Journals (Sweden)

    K. Gierens

    2013-11-01

    Full Text Available Aircraft at cruise levels can cause two kinds of contrails, the well known exhaust contrails and the less well-known aerodynamic contrails. While the possible climate impact of exhaust contrails has been studied for many years, research on aerodynamic contrails began only a few years ago and nothing is known about a possible contribution of these ice clouds to climate impact. In order to make progress in this respect, we first need a climatology of their formation conditions and this is given in the present paper. Aerodynamic contrails are defined here as line shaped ice clouds caused by aerodynamically triggered cooling over the wings of an aircraft in cruise which become visible immediately at the trailing edge of the wing or close to it. Effects at low altitudes like condensation to liquid droplets and their potential heterogeneous freezing are excluded from our definition. We study atmospheric conditions that allow formation of aerodynamic contrails. These conditions are stated and then applied to atmospheric data: first to a special case where an aerodynamic contrail was actually observed and then to a full year of global reanalysis data. We show where, when (seasonal variation, and how frequently (probability aerodynamic contrails can form, and how this relates to actual patterns of air traffic. We study the formation of persistent aerodynamic contrails as well. Furthermore, we check whether aerodynamic and exhaust contrails can coexist in the atmosphere. We show that visible aerodynamic contrails are possible only in an altitude range between roughly 540 and 250 hPa, and that the ambient temperature is the most important parameter, not the relative humidity. Finally, we argue that currently aerodynamic contrails have a much smaller climate effect than exhaust contrails, which may however change in future with more air traffic in the tropics.

  16. Mapping Atmospheric Moisture Climatologies across the Conterminous United States.

    Directory of Open Access Journals (Sweden)

    Christopher Daly

    Full Text Available Spatial climate datasets of 1981-2010 long-term mean monthly average dew point and minimum and maximum vapor pressure deficit were developed for the conterminous United States at 30-arcsec (~800m resolution. Interpolation of long-term averages (twelve monthly values per variable was performed using PRISM (Parameter-elevation Relationships on Independent Slopes Model. Surface stations available for analysis numbered only 4,000 for dew point and 3,500 for vapor pressure deficit, compared to 16,000 for previously-developed grids of 1981-2010 long-term mean monthly minimum and maximum temperature. Therefore, a form of Climatologically-Aided Interpolation (CAI was used, in which the 1981-2010 temperature grids were used as predictor grids. For each grid cell, PRISM calculated a local regression function between the interpolated climate variable and the predictor grid. Nearby stations entering the regression were assigned weights based on the physiographic similarity of the station to the grid cell that included the effects of distance, elevation, coastal proximity, vertical atmospheric layer, and topographic position. Interpolation uncertainties were estimated using cross-validation exercises. Given that CAI interpolation was used, a new method was developed to allow uncertainties in predictor grids to be accounted for in estimating the total interpolation error. Local land use/land cover properties had noticeable effects on the spatial patterns of atmospheric moisture content and deficit. An example of this was relatively high dew points and low vapor pressure deficits at stations located in or near irrigated fields. The new grids, in combination with existing temperature grids, enable the user to derive a full suite of atmospheric moisture variables, such as minimum and maximum relative humidity, vapor pressure, and dew point depression, with accompanying assumptions. All of these grids are available online at http://prism.oregonstate.edu, and

  17. Borehole climatology: a discussion based on contributions from climate modeling

    Directory of Open Access Journals (Sweden)

    J. F. González-Rouco

    2009-03-01

    Full Text Available Progress in understanding climate variability through the last millennium leans on simulation and reconstruction efforts. Exercises blending both approaches present a great potential for answering questions relevant both for the simulation and reconstruction of past climate, and depend on the specific peculiarities of proxies and methods involved in climate reconstructions, as well as on the realism and limitations of model simulations. This paper explores research specifically related to paleoclimate modeling and borehole climatology as a branch of climate reconstruction that has contributed significantly to our knowledge of the low frequency climate evolution during the last five centuries.

    The text flows around three main issues that group most of the interaction between model and geothermal efforts: the use of models as a validation tool for borehole climate reconstructions; comparison of geothermal information and model simulations as a means of either model validation or inference about past climate; and implications of the degree of realism on simulating subsurface climate on estimations of future climate change.

    The use of multi-centennial simulations as a surrogate reality for past climate suggests that within the simplified reality of climate models, methods and assumptions in borehole reconstructions deliver a consistent picture of past climate evolution at long time scales. Comparison of model simulations and borehole profiles indicate that borehole temperatures are responding to past external forcing and that more realism in the development of the soil model components in climate models is desirable. Such an improved degree of realism is important for the simulation of subsurface climate and air-ground interaction; results indicate it could also be crucial for simulating the adequate energy balance within climate change scenario experiments.

  18. Climatology of Aerosol Optical Properties in Southern Africa

    Science.gov (United States)

    Queface, Antonio J.; Piketh, Stuart J.; Eck, Thomas F.; Tsay, Si-Chee

    2011-01-01

    A thorough regionally dependent understanding of optical properties of aerosols and their spatial and temporal distribution is required before we can accurately evaluate aerosol effects in the climate system. Long term measurements of aerosol optical depth, Angstrom exponent and retrieved single scattering albedo and size distribution, were analyzed and compiled into an aerosol optical properties climatology for southern Africa. Monitoring of aerosol parameters have been made by the AERONET program since the middle of the last decade in southern Africa. This valuable information provided an opportunity for understanding how aerosols of different types influence the regional radiation budget. Two long term sites, Mongu in Zambia and Skukuza in South Africa formed the core sources of data in this study. Results show that seasonal variation of aerosol optical thicknesses at 500 nm in southern Africa are characterized by low seasonal multi-month mean values (0.11 to 0.17) from December to May, medium values (0.20 to 0.27) between June and August, and high to very high values (0.30 to 0.46) during September to November. The spatial distribution of aerosol loadings shows that the north has high magnitudes than the south in the biomass burning season and the opposite in none biomass burning season. From the present aerosol data, no long term discernable trends are observable in aerosol concentrations in this region. This study also reveals that biomass burning aerosols contribute the bulk of the aerosol loading in August-October. Therefore if biomass burning could be controlled, southern Africa will experience a significant reduction in total atmospheric aerosol loading. In addition to that, aerosol volume size distribution is characterized by low concentrations in the non biomass burning period and well balanced particle size contributions of both coarse and fine modes. In contrast high concentrations are characteristic of biomass burning period, combined with

  19. Lightning climatology in the Congo Basin: methodology and first results

    Science.gov (United States)

    Kigotsi, Jean; Soula, Serge; Georgis, Jean-François; Barthe, Christelle

    2016-04-01

    The global climatology of lightning issued from space observations (OTD and LIS) clearly showed the maximum of the thunderstorm activity is located in a large area of the Congo Basin, especially in the Democratic Republic of Congo (DRC). The first goal of the present study is to compare observations from the World Wide Lightning Location Network (WWLLN) from the Lightning Imaging Sensor (LIS) over a 9-year period (2005-2013) in this 2750 km × 2750 km area. The second goal is to analyse the lightning activity in terms of time and space variability. The detection efficiency (DE) of the WWLLN relative to LIS has increased between 2005 and 2013, typically from about 1.70 % to 5.90 %, in agreement with previous results for other regions of the world. The mean monthly flash rate describes an annual cycle with a maximum between November and March and a minimum between June and August, associated with the ICTZ migration but not exactly symmetrical on both sides of the equator. The diurnal evolution of the flash rate has a maximum between 1400 and 1700 UTC, depending on the reference year, in agreement with previous works in other regions of the world. The annual flash density shows a sharp maximum localized in eastern DRC regardless of the reference year and the period of the year. This annual maximum systematically located west of Kivu Lake corresponds to that previously identified by many authors as the worldwide maximum which Christian et al. (2013) falsely attributed to Rwanda. Another more extended region within the Congo Basin exhibits moderately large values, especially during the beginning of the period analyzed. A comparison of both patterns of lightning density from the WWLLN and from LIS allows to validate the representativeness of this world network and to restitute the total lightning activity in terms of lightning density and rate.

  20. Chemical climatology of the southeastern United States, 1999-2013

    Science.gov (United States)

    Hidy, G. M.; Blanchard, C. L.; Baumann, K.; Edgerton, E.; Tanenbaum, S.; Shaw, S.; Knipping, E.; Tombach, I.; Jansen, J.; Walters, J.

    2014-11-01

    A series of experiments (the Southern Oxidant and Aerosol Study - SOAS) took place in central Alabama in June-July, 2013 as part of the broader Southern Atmosphere Study (SAS). These projects were aimed at studying oxidant photochemistry and formation and impacts of aerosols at a detailed process level in a location where high biogenic organic vapor emissions interact with anthropogenic emissions, and the atmospheric chemistry occurs in a subtropical climate in North America. The majority of the ground-based experiments were located at the Southeastern Aerosol Research and Characterization (SEARCH) Centreville (CTR) site near Brent, Alabama, where extensive, unique aerometric measurements of trace gases and particles and meteorology were made beginning in the early 1990s through 2013. The SEARCH network data permits a characterization of the temporal and spatial context of the SOAS findings. Our earlier analyses of emissions and air quality trends are extended through 2013 to provide a perspective for continued decline in ambient concentrations, and the implications of these changes to regional sulfur oxide, nitrogen-ozone, and carbon chemistry. The narrative supports the SAS program in terms of long-term average chemistry (chemical climatology) and short-term comparisons of early summer average spatial variability across the southeastern US at high temporal (hourly) resolution. The long-term measurements show that the SOAS experiments took place during the second wettest and coolest year in the 2000-2013 period, with lower than average solar radiation. The pollution levels at CTR and other SEARCH sites were the lowest since full measurements began in 1999. Changes in anthropogenic gas and particle emissions between 1999 and 2013 account for the decline in pollutant concentrations at the monitoring sites in the region. The data provide an opportunity to contrast SOAS results with temporally and spatially variable conditions in support of the development of tests

  1. Climatology of Aerosol Optical Properties in Southern Africa

    Science.gov (United States)

    Queface, Antonio J.; Piketh, Stuart J.; Eck, Thomas F.; Tsay, Si-Chee

    2011-01-01

    A thorough regionally dependent understanding of optical properties of aerosols and their spatial and temporal distribution is required before we can accurately evaluate aerosol effects in the climate system. Long term measurements of aerosol optical depth, Angstrom exponent and retrieved single scattering albedo and size distribution, were analyzed and compiled into an aerosol optical properties climatology for southern Africa. Monitoring of aerosol parameters have been made by the AERONET program since the middle of the last decade in southern Africa. This valuable information provided an opportunity for understanding how aerosols of different types influence the regional radiation budget. Two long term sites, Mongu in Zambia and Skukuza in South Africa formed the core sources of data in this study. Results show that seasonal variation of aerosol optical thicknesses at 500 nm in southern Africa are characterized by low seasonal multi-month mean values (0.11 to 0.17) from December to May, medium values (0.20 to 0.27) between June and August, and high to very high values (0.30 to 0.46) during September to November. The spatial distribution of aerosol loadings shows that the north has high magnitudes than the south in the biomass burning season and the opposite in none biomass burning season. From the present aerosol data, no long term discernable trends are observable in aerosol concentrations in this region. This study also reveals that biomass burning aerosols contribute the bulk of the aerosol loading in August-October. Therefore if biomass burning could be controlled, southern Africa will experience a significant reduction in total atmospheric aerosol loading. In addition to that, aerosol volume size distribution is characterized by low concentrations in the non biomass burning period and well balanced particle size contributions of both coarse and fine modes. In contrast high concentrations are characteristic of biomass burning period, combined with

  2. A climatology of potential severe convective environments across South Africa

    Science.gov (United States)

    Blamey, R. C.; Middleton, C.; Lennard, C.; Reason, C. J. C.

    2017-09-01

    Severe thunderstorms pose a considerable risk to society and the economy of South Africa during the austral summer months (October-March). Yet, the frequency and distribution of such severe storms is poorly understood, which partly stems out of an inadequate observation network. Given the lack of observations, alternative methods have focused on the relationship between severe storms and their associated environments. One such approach is to use a combination of covariant discriminants, derived from gridded datasets, as a probabilistic proxy for the development of severe storms. These covariates describe some key ingredient for severe convective storm development, such as the presence of instability. Using a combination of convective available potential energy and deep-layer vertical shear from Climate Forecast System Reanalysis, this study establishes a climatology of potential severe convective environments across South Africa for the period 1979-2010. Results indicate that early austral summer months are most likely associated with conditions that are conducive to the development of severe storms over the interior of South Africa. The east coast of the country is a hotspot for potential severe convective environments throughout the summer months. This is likely due to the close proximity of the Agulhas Current, which produces high latent heat fluxes and acts as a key moisture source. No obvious relationship is established between the frequency of potential severe convective environments and the main large-scale modes of variability in the Southern Hemisphere, such as ENSO. This implies that several factors, possibly more localised, may modulate the spatial and temporal frequency of severe thunderstorms across the region.

  3. Understanding the Rainfall Daily Climatology of Northwestern Mexico

    Science.gov (United States)

    Brito-Castillo, L.

    2007-05-01

    Maximum monthly precipitation (MMP) over northwestern Mexico is not concurrent because it occurs in different months from July through September. However, instead of occurring progressively from one month to the next as latitude increases, as it might be logic since rains move progressively from south to north as monsoon develops, MMP occurs in July in latitudes of Jalisco state, then MMP shifts to August more to the north in latitudes of Nayarit state and along the eastern coast of the Gulf of California, then it occurs in July in higher latitudes through the main axis of the Sierra Madre Occidental (SMO), and finally MMP shifts to September to the west in the California Peninsula. The maximum monthly streamflow occurs in a similar pattern as MMP does but one month later. When daily rainfall climatology of the region is calculated, i.e. the long-term mean per day from stations with more than 20 years of data between 1940 and 2004, it is possible to understand why the behavior of MMP occurs in a July-August-July pattern from south to north. Preliminary results indicate that at latitudes of Nayarit state normal frequent storms with abundant rains develop at the end of July and through the August. These rains sum to the rains that move from the south to the north, as monsoon develops increasing the volume of precipitations at those latitudes in August. To the east crossing the SMO through northwestern Zacatecas state maximum volume of precipitations also is observed in August. However, in higher latitudes it is not observed any increment of rains in August and consequently maximum volume of precipitations occurs in July. To understand the dynamics of the rains at the latitudes of Nayarit state it results necessary to investigate the source of these local rains and explain why the increase of precipitations in August is limited at those latitudes.

  4. An Emerging Global Aerosol Climatology from the MODIS Satellite Sensors

    Science.gov (United States)

    Remer, Lorraine A.; Kleidman, Richard G.; Levy, Robert C.; Kaufman, Yoram J.; Tanre, Didier; Mattoo, Shana; Martins, J. Vandelei; Ichoku, Charles; Koren, Ilan; Hongbin, Yu; hide

    2008-01-01

    The recently released Collection 5 MODIS aerosol products provide a consistent record of the Earth's aerosol system. Comparison with ground-based AERONET observations of aerosol optical depth (AOD) we find that Collection 5 MODIS aerosol products estimate AOD to within expected accuracy more than 60% of the time over ocean and more than 72% of the time over land. This is similar to previous results for ocean, and better than the previous results for land. However, the new Collection introduces a 0.01 5 offset between the Terra and Aqua global mean AOD over ocean, where none existed previously. Aqua conforms to previous values and expectations while Terra is high. The cause of the offset is unknown, but changes to calibration are a possible explanation. We focus the climatological analysis on the better understood Aqua retrievals. We find that global mean AOD at 550 nm over oceans is 0.13 and over land 0.19. AOD in situations with 80% cloud fraction are twice the global mean values, although such situations occur only 2% of the time over ocean and less than 1% of the time over land. There is no drastic change in aerosol particle size associated with these very cloudy situations. Regionally, aerosol amounts vary from polluted areas such as East Asia and India, to the cleanest regions such as Australia and the northern continents. In almost all oceans fine mode aerosol dominates over dust, except in the tropical Atlantic downwind of the Sahara and in some months the Arabian Sea.

  5. On the integration of wind and solar energy to provide a total energy supply in the USA

    Science.gov (United States)

    Archer, Cristina; Mills, David; Cheng, Weili; Sloggy, Matthew; Liebig, Edwin; Rhoades, Alan

    2010-05-01

    This study examines the feasibility of using renewable energy - mostly wind and solar radiation - as the primary source of energy in the USA, under the assumption that a nationwide electric transmission grid is in place. Previous studies have shown that solar or wind alone can power the present U.S. grid on average. Other studies have shown that solar output from California and Texas using energy storage is well correlated with the state energy load on an hour by hour basis throughout the year and with the U.S. national load on a monthly basis. This study explores scenarios for use of wind and solar energy together at the national scale on an hour by hour basis to determine if such a combination is a better match to national seasonal load scenarios than either of the two alone on an hour-by-hour basis. Actual hour by hour national load data from the year 2006 are used as a basis, with some scenarios incorporating vehicle sector electrification and building heating and cooling using electric heat pumps. Hourly wind speed data were calculated at the hub height of 80 m above the ground for the year 2006 at over 150 windy locations in the continental U.S. using an extrapolation technique based on 10-m wind speed measurements and vertical sounding profiles. Using a 1.5 MW wind turbine as benchmark, the hourly wind power production nationwide was determined at all suitable locations. Similarly, the hourly output from solar plants, with and without thermal storage, was calculated based on Ausra's model assuming that the solar production would occur in the Southwest, the area with the greatest solar radiation density in the U.S. Hourly electricity demand for the year 2006 was obtained nationwide from a variety of sources, including the Federal Energy Regulation Commission. Hourly residential heating and cooking, industrial heat processing, and future electrified transportation loads were calculated from monthly and yearly energy consumption data from the Energy Information

  6. Wind turbines

    OpenAIRE

    Jorge, Clàudia; Stuer, Joris; Mahy, Philip; Hawksley, Will

    2013-01-01

    The European Project Semester is about much more than a period of study, it is an opportunity to explore new surroundings and embrace new cultures, all while studying in a unique environment with a blend of people from diff erent disciplines. Our project, put together with the help of our supervisor Gunther Steenackers fi nds three product developers and one ICT engineer coming together to work on a project for an urban wind turbine. Our Aim is as follows: “We wi...

  7. Wind conditions for wind turbine design

    Energy Technology Data Exchange (ETDEWEB)

    Maribo Pedersen, B.

    1999-04-01

    Delegates from Europe and USA attended the meeting and discussed general aspects of wind conditions for wind turbine design. The subjects and the presented papers covered a very broad range of aspects of wind conditions and related influence on the wind turbine. (EHS)

  8. First look at the NOAA Aircraft-based Tropospheric Ozone Climatology

    Science.gov (United States)

    Leonard, M.; Petropavlovskikh, I. V.; McClure-Begley, A.; Lin, M.; Tarasick, D.; Johnson, B. J.; Oltmans, S. J.

    2015-12-01

    The Global Greenhouse Gas Reference Network's aircraft program has operated since the 1990s as part of the NOAA Global Monitoring Division network to capture spatial and temporal variability in greenhouse tracers (i.e. CO2, CO, N2O, methane, SF6, halo- and hydro-carbons). Since 2005 the suite of airborne measurements also includes ozone, humidity and temperature profiling through the troposphere (up to 8 km). Light commercial aircraft are equipped with modified 2B Technology ozone monitors (Model 205DB), incorporate temperature and humidity probes, and include global positioning system instrumentation. The dataset was analyzed for tropospheric ozone variability at five continental US stations. As site locations within the Tropospheric Aircraft Ozone Measurement Program have flights only once (four times at one site) a month and begun a decade ago, this raises the question of whether this sampling frequency allows the derivation of an accurate vertical climatology of ozone values. We interpret the representativeness of the vertical and seasonal ozone distribution from aircraft measurements using multi-decadal hindcast simulations conducted with the GFDL AM3 chemistry-climate model. When available, climatology derived from co-located ozone-sonde data will be used for comparisons. The results of the comparisons are analyzed to establish altitude ranges in the troposphere where the aircraft climatology would be deemed to be the most representative. Aircraft-based climatologies are tested from two approaches: comparing the aircraft-based climatology to the daily sampled model and to the subset of model data with matching aircraft dates. Whenever the model and aircraft climatologies show significant seasonal differences, further information is gathered from a seasonal Gaussian distribution plot. We will report on the minimum frequency in flights that can provide adequate climatological representation of seasonal and vertical variability in tropospheric ozone.

  9. Establishment of Short-Term Wind Speed Prediction Model for New Wind Farm%新投产风电场的短期风速预测模型建立

    Institute of Scientific and Technical Information of China (English)

    陈欣; 孙翰墨; 申烛; 孟凯锋; 岳捷

    2014-01-01

    常规的风电场功率预测建模主要方法是将数值天气预报产生的气象要素输入基于历史scada数据建立统计模型,得到全场预报总功率。但是新投产的风电场没有历史scada数据,而风电场功率预测的准确性主要依赖于短期风速预报的精度。因此,为提高新投产风电场功率预测的准确性,短期风速预报的建立是基于数值气象预报的物理模型和统计模型相结合的方式。首先,通过数值气象模式输出风电场测风塔处轮毂高度层的气象要素;其次,通过建立神经网络模型和多元线性回归两种统计方法对模式输出数据进行修正;最后,对误差的来源进行分类分析。在江苏某风场的测试结果表明,较传统的方式,预测精度有了明显的提高,该方法能够消除数值气象预报的振幅偏差,但相位偏差仍是误差的主要来源。%Conventional wind power prediction method primarily uses numerical weather prediction to generate histori-cal scada data and build statistical model, by which the total power prediction is made. As the new wind farm could not collect historical scada data, the accuracy of the wind farm power prediction relies on the accuracy of short-term wind speed prediction. Therefore, to improve the accuracy of wind power prediction for new wind farm, the short-term wind speed prediction is established based on the combination of physical and statistical models of numerical weather prediction. First, the numerical weather model is used to output the meteorological element at turbine hub height lay-ers. Second, the output data are corrected by the establishment of neural network model and multiple linear regression model. Finally, sources of errors are classified and analyzed. Results of wind farm test in Jiangsu province indicate that, compared with traditional methods, this method can significantly improve the accuracy of wind speed prediction and eliminate the

  10. Wind Technologies & Evolving Opportunities (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Robichaud, R.

    2014-07-01

    This presentation covers opportunities for wind technology; wind energy market trends; an overview of the National Wind Technology Center near Boulder, Colorado; wind energy price and cost trends; wind turbine technology improvements; and wind resource characterization improvements.

  11. The Climatology of Taiwan extreme rainfall events and the attributions

    Science.gov (United States)

    Su, S. H.; Kuo, H. C.; Chen, Y. H.; Chu, J. L.; Lin, L. Y.

    2015-12-01

    Taiwan is located in the East-Asian monsoon region with average 2,500mm annual precipitation. Most significant Meteorological disasters are related to extreme precipitation which is associated with a complex terrain. Therefore, the long-term trends or climate variations in precipitation due to climate change are our major concern. We studied the climatology of extreme rainfall (ER, 95thpercentile) events in Taiwan using hourly precipitation data form 21 surface stations during 1960-2014. ER contributes about 40% of the total rain amount. It was found that approximately 68% of ER is related to typhoon (TY) and 22% associated with the Mei-Yu (MY) frontal system. The total ER amount annual variation is strongly related to TY, with correlation coefficient of 0.89 for rainfall amount and 0.86 for frequency. There is a significant increasing trend of TY-ER in past 55 years, but also has large variations over the annual and decadal time scales. The inter-annual variation of astounding extreme rainfall (AER, 99.9thpercentile) is increased significantly, especially in the past 15 years. It implies that the increasing of AER rainfall amount majorly caused by the increasing of frequency instead of average rain intensity of TY-AER. The MY-ER events are also highly correlated with the frontal system. The correlation is 0.84 for the rainfall amount and 0.83 of the frequency with the frontal days. There are also strong inter-annual variations of MY-ER, but the long-term trends are not as significant as TY-ER. The variation of frontal system number is another parameter may impact the MY-ER. The observational frontal system numbers had positive correlation with the MY-ER. The attribution of Taiwan TY-ER changes was debated in the research community. In general, the public acceptance of Taiwan extreme precipitation events is affected by multi-scale systems. According to observational data, the increasing of TY-ER amount is 37 % (48% )in Taiwan and some resent studies (Wang et al

  12. The European 2015 drought from a climatological perspective

    Science.gov (United States)

    Ionita, Monica; Tallaksen, Lena M.; Kingston, Daniel G.; Stagge, James H.; Laaha, Gregor; Van Lanen, Henny A. J.; Scholz, Patrick; Chelcea, Silvia M.; Haslinger, Klaus

    2017-03-01

    The summer drought of 2015 affected a large portion of continental Europe and was one of the most severe droughts in the region since summer 2003. The summer of 2015 was characterized by exceptionally high temperatures in many parts of central and eastern Europe, with daily maximum temperatures 2 °C higher than the seasonal mean (1971-2000) over most of western Europe, and more than 3 °C higher in the east. It was the hottest and climatologically driest summer over the 1950-2015 study period for an area stretching from the eastern Czech Republic to Ukraine. For Europe, as a whole, it is among the six hottest and driest summers since 1950. High evapotranspiration rates combined with a lack of precipitation affected soil moisture and vegetation and led to record low river flows in several major rivers, even beyond the drought-hit region. The 2015 drought developed rather rapidly over the Iberian Peninsula, France, southern Benelux and central Germany in May and reached peak intensity and spatial extent by August, affecting especially the eastern part of Europe. Over the summer period, there were four heat wave episodes, all associated with persistent blocking events. Upper-level atmospheric circulation over Europe was characterized by positive 500 hPa geopotential height anomalies flanked by a large negative anomaly to the north and west (i.e., over the central North Atlantic Ocean extending to northern Fennoscandia) and another center of positive geopotential height anomalies over Greenland and northern Canada. Simultaneously, the summer sea surface temperatures (SSTs) were characterized by large negative anomalies in the central North Atlantic Ocean and large positive anomalies in the Mediterranean basin. Composite analysis shows that the western Mediterranean SST is strongly related to the occurrence of dry and hot summers over the last 66 years (especially over the eastern part of Europe). The lagged relationship between the Mediterranean SST and summer drought

  13. A Climatological Investigation of the Activity of Summer Subtropical Vortices

    Institute of Scientific and Technical Information of China (English)

    LUO Zhexian; DAI Kan

    2008-01-01

    By applying a new vortex detection method to the ECMWF 40-yr reanalysis (ERA40) data from 1985 to 2002, the climatology of summer vortices has been investigated in five subtropical regions, i.e., the northwestern Pacific, northeastern Pacific, northwestern Atlantic, northeastern Atlantic, and Australia-South Pacific, followed by validation with NCEP/NCAR reanalysis data. Results are as follows: (1) The spatial distributions of ERA40 vortex activities (VAC) were well consistent with those of NCEP/NCAR reanalysis (NRA) results in all regions, especially in northwestern Pacific. (2) Because of different model resolutions, both the number and intensity of vortices obtained from NRA were significantly weaker thanERA40's. (3) Vortices mainly cruised in coasts and the adjacent seas, from where to the land or the open sea vortex activities were gradually decreased. (4) There were two active centers in the northwestern Pacific:one was located in South China Sea and the other, as the largest center of the five regions, spread from the east side of the Philippines to Japan. (5) Over the northwestern Atlantic, most vortices occurred in Panama and its west-side offshore. (6) The spatial distributions of vortices were alike between the northeastern Pacific and northeastern Atlantic, both spreading from coasts to the west-side sea at 5°-20°N. (7) In the Anstralia-South Pacific, vortices were not as active as those in the other four regions, and mostly took place in the equator-side of near ocean areas. (8) Except the northwestern Pacific and northwestern Atlantic, the VAC interannual variations in the other three regions were different between ERA40 and NRA data. (9)In the northwestern Pacific and northwestern Atlantic, the VAC interannual variation could be separated to several distinct stages. (10) Since the mid 1980s, mean vortex intensity was getting increased in the northwestern Pacific, which was most significant in the subtropical areas on a global basis. In the western

  14. Power-Production Diagnostic Tools for Low-Density Wind Farms with Applications to Wake Steering

    Science.gov (United States)

    Takle, E. S.; Herzmann, D.; Rajewski, D. A.; Lundquist, J. K.; Rhodes, M. E.

    2016-12-01

    Hansen (2011) provided guidelines for wind farm wake analysis with applications to "high density" wind farms (where average distance between turbines is less than ten times rotor diameter). For "low-density" (average distance greater than fifteen times rotor diameter) wind farms, or sections of wind farms we demonstrate simpler sorting and visualization tools that reveal wake interactions and opportunities for wind farm power prediction and wake steering. SCADA data from a segment of a large mid-continent wind farm, together with surface flux measurements and lidar data are subjected to analysis and visualization of wake interactions. A time-history animated visualization of a plan view of power level of individual turbines provides a quick analysis of wake interaction dynamics. Yaw-based sectoral histograms of enhancement/decline of wind speed and power from wind farm reference levels reveals angular width of wake interactions and identifies the turbine(s) responsible for the power reduction. Concurrent surface flux measurements within the wind farm allowed us to evaluate stability influence on wake loss. A one-season climatology is used to identify high-priority candidates for wake steering based on estimated power recovery. Typical clearing prices on the day-ahead market are used to estimate the added value of wake steering. Current research is exploring options for identifying candidate locations for wind farm "build-in" in existing low-density wind farms.

  15. The WEI6K, a 6-kW 7-m Small Wind Turbine: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, Kyle K.; McCleer, Patrick J.; Hahlbeck, Edwin C.; DOE Project Office - Keith Bennett

    2006-07-21

    This project was selected by the U.S. Department of Energy under a DOE solicitation “Low Wind Speed Technology for Small Turbine Development.” The objective of this project has been to design a new small wind turbine with improved cost, reliability and performance in grid-connected residential and small business applications, in order to achieve the overall DOE goal of cost effectiveness in Class 3 wind resources that can now be achieved in Class 5 resources. The scope of work for this project has been to complete the preliminary design of an improved small wind turbine, including preliminary loads and strength analyses; analysis and design of all major components; systems integration and structural dynamic analysis; estimation of life-cycle cost of energy; and design documentation and review. The project did not entail hardware fabrication or testing. The WEI6K Turbine resulting from this project is an upwind horizontal-axis wind turbine rated at 6 kW. It features a 3-blade 7-m diameter rotor. The generator is a direct-drive permanent magnet synchronous machine generating 3-phase power at 240 VAC. The turbine is maintained oriented in to the wind via active yaw control using electromechanical servos. Power is regulated with active blade pitch control. The turbine is presently designed to be placed on a 100-foot (30m) tower. The turbine is predicted to generate electricity at a levelized cost of energy (COE) between 7.3 and 8.9 ¢/kWh at an IEC Class II site, with an average wind speed of 8.5 m/s at hub height, depending upon whether the customer uses a guyed truss tower (the lower figure) or a monopole tower. For the NREL Reference Site, with a mean wind speed of 5.35 m/s at 10 m height, the turbine would generate at a levelized cost of energy of between 9.7 and 11.9 ¢/kWh. The lowest of these numbers is presently competitive with retail electricity rates in most of the country. The 8.9 ¢/kWh is still competitive with retail rates in many regions of the

  16. Towards a climatology of tropical cyclone morphometric structures using a newly standardized passive microwave satellite dataset

    Science.gov (United States)

    Cossuth, J.; Hart, R. E.

    2013-12-01

    The structure of a tropical cyclone (TC) is a spatial representation of its organizational pattern and distribution of energy acquisition and release. Physical processes that react to both the external environment and its own internal dynamics manifest themselves in the TC shape. This structure depicts a specific phase in the TC's meteorological lifecycle, reflecting its past and potentially constraining its future development. For a number of reasons, a thorough objective definition of TC structures and an intercomparison of their varieties have been neglected. This lack of knowledge may be a key reason why TC intensity forecasts, despite numerical model improvements and theoretical advances, have been stagnant in recent years relative to track forecasts. Satellite microwave imagers provide multiple benefits in discerning TC structure, but compiling a research quality data set has been problematic due to several inherent technical and logistical issues. While there are multiple satellite sensors that incorporate microwave frequencies, inter-comparison between such sensors is limited by the different available channels, spatial resolutions, and calibration metrics between satellites, all of which provide inconsistencies in resolving TC structural features. To remedy these difficulties, a global archive of TCs as measured by all available US satellite microwave sensors is compiled and standardized. Using global historical best track data, TC microwave data is retrieved from the Defense Meteorological Satellite Program (DMSP) series (including all SSM/I and SSMIS), TMI, AMSR-E, and WindSat sensors. Standardization between sensors for each TC overpass are performed, including: 1) Recalibration of data from the 'ice scattering' channels to a common frequency (89GHz); 2) Resampling the DMSP series to a higher resolution using the Backus-Gilbert technique; and 3) Re-centering the TC center more precisely using the ARCHER technique (Wimmers and Velden 2010) to analyze the

  17. Lower-tropospheric humidity: climatology, trends and the relation to the ITCZ

    Directory of Open Access Journals (Sweden)

    Alexander Läderach

    2013-07-01

    Full Text Available The tropical region is an area of maximum humidity and serves as the major humidity source of the globe. Among other phenomena, it is governed by the so-called Inter-Tropical Convergence Zone (ITCZ which is commonly defined by converging low-level winds or enhanced precipitation. Given its importance as a humidity source, we investigate the humidity fields in the tropics in different reanalysis data sets, deduce the climatology and variability and assess the relationship to the ITCZ. Therefore, a new analysis method of the specific humidity distribution is introduced which allows detecting the location of the humidity maximum, the strength and the meridional extent. The results show that the humidity maximum in boreal summer is strongly shifted northward over the warm pool/Asia Monsoon area and the Gulf of Mexico. These shifts go along with a peak in the strength in both areas; however, the extent shrinks over the warm pool/Asia Monsoon area, whereas it is wider over the Gulf of Mexico. In winter, such connections between location, strength and extent are not found. Still, a peak in strength is again identified over the Gulf of Mexico in boreal winter. The variability of the three characteristics is dominated by inter-annual signals in both seasons. The results using ERA-interim data suggest a positive trend in the Gulf of Mexico/Atlantic region from 1979 to 2010, showing an increased northward shift in the recent years. Although the trend is only weakly confirmed by the results using MERRA reanalysis data, it is in phase with a trend in hurricane activity – a possible hint of the importance of the new method on hurricanes. Furthermore, the position of the maximum humidity coincides with one of the ITCZ in most areas. One exception is the western and central Pacific, where the area is dominated by the double ITCZ in boreal winter. Nevertheless, the new method enables us to gain more insight into the humidity distribution, its variability and

  18. Unexpected climatological behavior of MLT gravity wave momentum flux in the lee of the Southern Andes hot spot

    Science.gov (United States)

    Wit, R. J.; Janches, D.; Fritts, D. C.; Stockwell, R. G.; Coy, L.

    2017-01-01

    The Southern Argentina Agile MEteor Radar (SAAMER), located at Tierra del Fuego (53.7°S, 67.7°W), has been providing near-continuous high-resolution measurements of winds and high-frequency gravity wave (GW) momentum fluxes of the mesopause region since May 2008. As SAAMER is located in the lee of the largest seasonal GW hot spot on Earth, this is a key location to study GWs and their interaction with large-scale motions. GW momentum flux climatologies are shown for the first time for this location and discussed in light of these unique dynamics. Particularly, the large eastward GW momentum fluxes during local winter are surprising, as these observations cannot be explained by the direct upward propagation of expected large-amplitude mountain waves (MWs) through the eastward stratospheric jet. Instead, these results are interpreted as secondary GWs propagating away from stratospheric sources over the Andes accompanying MW breaking over the Southern Andes.

  19. Unexpected Climatological Behavior of MLT Gravity Wave Momentum Flux in the Lee of the Southern Andes Hot Spot

    Science.gov (United States)

    DeWit, R. J.; Janches, D.; Fritts, D. C.; Stockwell, R. G.; Coy, L.

    2017-01-01

    The Southern Argentina Agile MEteor Radar (SAAMER), located at Tierra del Fuego (53.7degS, 67.7degW), has been providing near-continuous high-resolution measurements of winds and high-frequency gravity wave (GW) momentum fluxes of the mesopause region since May 2008. As SAAMER is located in the lee of the largest seasonal GW hot spot on Earth, this is a key location to study GWs and their interaction with large-scale motions. GW momentum flux climatologies are shown for the first time for this location and discussed in light of these unique dynamics. Particularly, the large eastward GW momentum fluxes during local winter are surprising, as these observations cannot be explained by the direct upward propagation of expected large-amplitude mountain waves (MWs) through the eastward stratospheric jet. Instead, these results are interpreted as secondary GWs propagating away from stratospheric sources over the Andes accompanying MW breaking over the Southern Andes.

  20. A global study of temporal and spatial variation of SWH and wind speed and their correlation

    Institute of Scientific and Technical Information of China (English)

    HAN Shuzong; ZHANG Huirong; ZHENG Yunxia

    2014-01-01

    The climatology of significant wave height (SWH) and sea surface wind speed are matters of concern in the fields of both meteorology and oceanography because they are very important parameters for planning offshore structures and ship routings. The TOPEX/Poseidon altimeter, which collected data for about 13 years from September 1992 to October 2005, has measured SWHs and surface wind speeds over most of the world’s oceans. In this paper, a study of the global spatiotemporal distributions and variations of SWH and sea surface wind speed was conducted using the TOPEX/Poseidon altimeter data set. The range and char-acteristics of the variations were analyzed quantitatively for the Pacific, Atlantic, and Indian oceans. Areas of rough waves and strong sea surface winds were localized precisely, and the correlation between SWH and sea surface wind speed analyzed.

  1. News and trends in Wind Power. Review 2010; Nytt och trendigt inom vindkraften. Omvaerldsbevakning 2010

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Staffan

    2010-08-15

    has emerged in e.g. Sweden. During the beginning of 2010 a 200 kW vertical axis wind turbine was erected in Falkenberg. In general the data for the new Swedish wind turbine are normal for vertical axis machines. The greatest advantage is probably the simplicity, with in principle only one moving structure. A major part of the load-carrying construction is made from gluelam, which is known to be cost-effective and resistant towards fatigue. Welded steel tube towers have been the dominating technology for producing towers for wind turbines for a long time. In order to utilize the material in the best possible way, they preferably are made conical. For a MW-size wind turbine a base diameter of 4,5 meters is reached at a hub height of around 100 meters. This also is limit for road transportation. Alternative tower technologies are to assemble the steel plates with screw joints only, towers made of pretensioned concrete, steel-concrete hybrids, lattice towers and also wooden towers. The development of the electrical systems of the wind turbines to a large extent is driven by the increased demand for regulation and ability to withstand disturbances that are a consequence of the increasing share of wind power in the electricity production. A consequence has been the trend towards using synchronous generators, either high-speed in combination with a gearbox, or directly driven. In both cases they are combined with an electrical converter, which is dimensioned for the total power of the power plant. The increasing size of the generators per se justifies a transition to higher voltages than the so far prevailing 690 V. However, medium voltage converters are so far more expensive than the ones for low voltage. A premium is to get rid of the transformer in the nacelle, alternatively to avoid a heavy and expensive low voltage cable through the tower. In a 10 MW offshore wind turbine, developed by AMSC Windtec, the direct drive generator is magnetized by super conducting rotor

  2. A new global interior ocean mapped climatology: the 1° × 1° GLODAP version 2

    Science.gov (United States)

    Lauvset, Siv K.; Key, Robert M.; Olsen, Are; van Heuven, Steven; Velo, Anton; Lin, Xiaohua; Schirnick, Carsten; Kozyr, Alex; Tanhua, Toste; Hoppema, Mario; Jutterström, Sara; Steinfeldt, Reiner; Jeansson, Emil; Ishii, Masao; Perez, Fiz F.; Suzuki, Toru; Watelet, Sylvain

    2016-08-01

    We present a mapped climatology (GLODAPv2.2016b) of ocean biogeochemical variables based on the new GLODAP version 2 data product (Olsen et al., 2016; Key et al., 2015), which covers all ocean basins over the years 1972 to 2013. The quality-controlled and internally consistent GLODAPv2 was used to create global 1° × 1° mapped climatologies of salinity, temperature, oxygen, nitrate, phosphate, silicate, total dissolved inorganic carbon (TCO2), total alkalinity (TAlk), pH, and CaCO3 saturation states using the Data-Interpolating Variational Analysis (DIVA) mapping method. Improving on maps based on an earlier but similar dataset, GLODAPv1.1, this climatology also covers the Arctic Ocean. Climatologies were created for 33 standard depth surfaces. The conceivably confounding temporal trends in TCO2 and pH due to anthropogenic influence were removed prior to mapping by normalizing these data to the year 2002 using first-order calculations of anthropogenic carbon accumulation rates. We additionally provide maps of accumulated anthropogenic carbon in the year 2002 and of preindustrial TCO2. For all parameters, all data from the full 1972-2013 period were used, including data that did not receive full secondary quality control. The GLODAPv2.2016b global 1° × 1° mapped climatologies, including error fields and ancillary information, are available at the GLODAPv2 web page at the Carbon Dioxide Information Analysis Center (CDIAC; doi:10.3334/CDIAC/OTG.NDP093_GLODAPv2).

  3. Wind Streaks

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 12 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. Windstreaks are features caused by the interaction of wind and topographic landforms. The raised rims and bowls of impact craters causes a complex interaction such that the wind vortex in the lee of the crater can both scour away the surface dust and deposit it back in the center of the lee. If you look closely, you will see evidence of this in a darker 'rim' enclosing a brighter interior. Image information: VIS instrument. Latitude 6.9, Longitude 69.4 East (290.6 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing

  4. Careers in Wind Energy

    Science.gov (United States)

    Liming, Drew; Hamilton, James

    2011-01-01

    As a common form of renewable energy, wind power is generating more than just electricity. It is increasingly generating jobs for workers in many different occupations. Many workers are employed on wind farms: areas where groups of wind turbines produce electricity from wind power. Wind farms are frequently located in the midwestern, western, and…

  5. Prospecting for Wind

    Science.gov (United States)

    Swapp, Andy; Schreuders, Paul; Reeve, Edward

    2011-01-01

    Many people use wind to help meet their needs. Over the years, people have been able to harness or capture the wind in many different ways. More recently, people have seen the rebirth of electricity-generating wind turbines. Thus, the age-old argument about technology being either good or bad can also be applied to the wind. The wind can be a…

  6. Prospecting for Wind

    Science.gov (United States)

    Swapp, Andy; Schreuders, Paul; Reeve, Edward

    2011-01-01

    Many people use wind to help meet their needs. Over the years, people have been able to harness or capture the wind in many different ways. More recently, people have seen the rebirth of electricity-generating wind turbines. Thus, the age-old argument about technology being either good or bad can also be applied to the wind. The wind can be a…

  7. Wind speed and direction predictions by WRF and WindSim coupling over Nygårdsfjell

    Science.gov (United States)

    Bilal, M.; Solbakken, K.; Birkelund, Y.

    2016-09-01

    In this study, the performance of the mesoscale meteorological Weather Research and Forecast (WRF) model coupled with the microscale computational fluid dynamics based model WindSim is investigated and compared to the performance of WRF alone. The two model set-ups, WRF and WRF-WindSim, have been tested on three high-wind events in February, June and October, over a complex terrain at the Nygårdsfjell wind park in Norway. The wind speeds and wind directions are compared to measurements and the results are evaluated based on root mean square error, bias and standard deviation error. Both model set-ups are able to reproduce the high wind events. For the winter month February the WRF-WindSim performed better than WRF alone, with the root mean square error (RMSE) decreasing from 2.86 to 2.38 and standard deviation error (STDE) decreasing from 2.69 to 2.37. For the two other months no such improvements were found. The best model performance was found in October where the WRF had a RMSE of 1.76 and STDE of 1.68. For June, both model set-ups underestimate the wind speed. Overall, the adopted coupling method of using WRF outputs as virtual climatology for coupling WRF and WindSim did not offer a significant improvement over the complex terrain of Nygårdsfjell. However, the proposed coupling method offers high degree of simplicity when it comes to its application. Further testing is recommended over larger number of test cases to make a significant conclusion.

  8. The Effect of Heat Waves and Drought on Surface Wind Circulations in the Northeast of the Iberian Peninsula during the Summer of 2003

    NARCIS (Netherlands)

    Jiménez, P.A.; Vilà-Guerau de Arellano, J.; González-Rouco, J.F.; Navarro, J.; Montávez, J.P.; García-Bustamante, E.; Dudhia, J.

    2011-01-01

    Variations in the diurnal wind pattern associated with heat waves and drought conditions are investigated climatologically at a regional level (northeast of the Iberian Peninsula). The study, based on high-density observational evidence and fine spatial-scale mesoscale modeling for the 1992–2004 per

  9. Designing an H-rotor type Wind Turbine for Operation on Amundsen-Scott South Pole Station

    OpenAIRE

    Wahl, Mats

    2007-01-01

    This thesis focuses on designing the turbine, tower structure and generator for an H-rotor type wind turbine. The produced power will be used for heating of drilling equipment, stored in containers, on the Amundsen-Scott South Pole Station. A 23 kW wind turbine producing 5 kW on average has been designed. Moreover, the design has been tested to be mounted on top of the container storing the drilling equipment. Climatological data have been processed to describe the wind regime in useful terms...

  10. Tower Winds - Cape Kennedy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Digitized data taken from Wind Gust Charts. Record contains hourly wind directions and speed with a peak wind recorded at the end of each day. Sorted by: station,...

  11. Peak Wind Forecasts for the Launch-Critical Wind Towers on Kennedy Space Center/Cape Canaveral Air Force Station, Phase IV

    Science.gov (United States)

    Crawford, Winifred

    2011-01-01

    This final report describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The peak winds arc an important forecast clement for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to update the statistics in the current peak-wind forecast tool to assist in forecasting LCC violations. The tool includes onshore and offshore flow climatologies of the 5-minute mean and peak winds and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  12. A Smart Climatology of Evaporation Duct Height and Surface Radar Propagation in the Indian Ocean

    Science.gov (United States)

    2007-09-01

    closest Marsden square for the existing climatology and from the closest grid point for our smart climatology. 77 Comparison Climo vs Bouy 0 5 10...15 20 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec E D H ( m ) Bouy EDH AREPS MS066 NCEP 1970-2006 NCEP 1994/95 Comparison Climo vs Bouy 0 5 10...15 20 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec E D H ( m ) Bouy EDH AREPS MS066 NCEP 1970-2006 NCEP 1994/95 Comparison Climo vs Bouy 0 5 10 15

  13. The Increasing Use of Remote Sensing Data in Studying the Climatological Impacts on Public Health

    Science.gov (United States)

    Kempler, Steven; Benedict, Karl; Ceccato, Pietro; Golden, Meredith; Maxwell, Susan; Morian, Stan; Soebiyanto, Radina; Tong, Daniel

    2011-01-01

    One of the more fortunate outcomes of the capture and transformation of remote sensing data into applied information is their usefulness and impacts to better understanding climatological impacts on public health. Today, with petabytes of remote sensing data providing global coverage of climatological parameters, public health research and policy decision makers have an unprecedented (and growing) data record that relates the effects of climatic parameters, such as rainfall, heat, soil moisture, etc. to incidences and spread of disease, as well as predictive modeling. In addition, tools and services that specifically serve public health researchers and respondents have grown in response to needs of the these information users.

  14. Assessment of daily reference evapotranspiration in Sicily by means of POWER-NASA agro-climatology archive

    Science.gov (United States)

    Negm, Amro; Jabro, Jay; Provenzano, Giuseppe

    2016-04-01

    The importance of evapotranspiration, ET, processes has long been recognized in many disciplines, including hydrologic and drainage studies as well as for irrigation system design and management. A wide number of equations have been proposed to estimate crop reference evapotranspiration, ET0, based on the variables affecting the process. When a full data set of climate variables is available, the Food and Agriculture Organization (FAO) of the United Nations recommended to use the physically based FAO-56 Penman-Monteith equation. The lack of climate variables and particularly of solar radiation has led several researchers to propose simplified ET0 estimation equations using a limited number of climate variables. These equations, however, need site-specific validation prior to their use and cannot be generalized. Recently, the American National Aeronautics and Space Administration (NASA), created an efficient and open access agro-climatology archive in the frame of the Prediction Of Worldwide Energy Resource (POWER) project containing, on global scale, a long-series of meteorological variables and surface solar energy fluxes. The main objective of the research was to assess the suitability of POWER-NASA open access archive to estimate daily reference evapotranspiration, ET0, in Sicily, for the period 2006-2014. Daily ET0 were evaluated according to FAO-56 PM equation, by considering the POWER-NASA database characterized by a grid resolution of 1° latitude × 1° longitude, as well as the climate data measured on the ground, by a network of 36 meteorological stations installed in Sicily and belonging to the Agro-meteorological Information Service (SIAS). After comparing the climate data available in both databases (minimum, maximum and average air temperature and relative air humidity, wind speed, solar radiation and air pressure), a statistical comparison was also carried out on ET0 values estimated with the FAO-56 PM equation. The analysis showed a good correlation

  15. Extreme Velocity Wind Sensor

    Science.gov (United States)

    Perotti, Jose; Voska, Ned (Technical Monitor)

    2002-01-01

    This presentation provides an overview of the development of new hurricane wind sensor (Extreme Velocity Wind Sensor) for the Kennedy Space Center (KSC) which is designed to withstand winds of up to three hundred miles an hour. The proposed Extreme Velocity Wind Sensor contains no moveable components that would be exposed to extreme wind conditions. Topics covered include: need for new hurricane wind sensor, conceptual design, software applications, computational fluid dynamic simulations of design concept, preliminary performance tests, and project status.

  16. Applications of SMAP data to retrieval of ocean surface wind and salinity

    Science.gov (United States)

    Yueh, Simon; Fore, Alexander; Tang, Wenqing; Hayashi, Akiko; Stiles, Bryan; Zhang, Fuqing; Weng, Yonghui; Real, Nicolas

    2016-10-01

    We have examined the L-band radiometer and radar data from NASA's Soil Moisture Active Passive (SMAP) mission for ocean research and applications. We find that the SMAP data are in excellent agreement with the geophysical model function (GMF) derived from the Aquarius data up to a wind speed of 20 ms-1. For severe wind conditions, the higher resolution data from SMAP allowed us to assess the sensitivity of L-band radiometer signals to hurricane force winds. We applied the L-band GMF to the retrieval of ocean surface wind and SSS from the SMAP data. Comparison with the European Center for Medium-Range Weather Forecasting, WindSat and RapidSCAT wind speeds suggests that SMAP's radiometer wind speed reaches an excellent accuracy of about 1.1-1.7 ms-1 below a wind speed of 20 ms-1. We have also found that the maximum wind speed derived from the SMAP radiometer data can reach 140 knots for severe storms and are generally in good agreement with the hurricane track analysis and operational aircraft Stepped Frequency Microwave Radiometer wind speeds. The spatial patterns of the SMAP SSS agree well with climatological distributions, but exhibit several unique spatial and temporal features.

  17. Wind for Schools (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Baring-Gould, I.

    2010-05-01

    As the United States dramatically expands wind energy deployment, the industry is challenged with developing a skilled workforce and addressing public resistance. Wind Powering America's Wind for Schools project addresses these issues by developing Wind Application Centers (WACs) at universities; WAC students assist in implementing school wind turbines and participate in wind courses, by installing small wind turbines at community "host" schools, by implementing teacher training with interactive curricula at each host school. This poster provides an overview of the first two years of the Wind for Schools project, primarily supporting activities in Colorado, Kansas, Nebraska, South Dakota, Montana, and Idaho.

  18. Wind energy bibliography

    Energy Technology Data Exchange (ETDEWEB)

    None

    1995-05-01

    This bibliography is designed to help the reader search for information on wind energy. The bibliography is intended to help several audiences, including engineers and scientists who may be unfamiliar with a particular aspect of wind energy, university researchers who are interested in this field, manufacturers who want to learn more about specific wind topics, and librarians who provide information to their clients. Topics covered range from the history of wind energy use to advanced wind turbine design. References for wind energy economics, the wind energy resource, and environmental and institutional issues related to wind energy are also included.

  19. Synergistic Effects of Turbine Wakes and Atmospheric Stability on Power Production at an Onshore Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S; Lundquist, J K; Marjanovic, N

    2012-01-25

    recovers to its inflow velocity is dependent on the amount ambient turbulence, the amount of wind shear, and topographical and structural effects. The maximum velocity deficit is estimated to occur at 1-2 D but can be longer under low levels of ambient turbulence. Our understanding of turbine wakes comes from wind tunnel experiments, field experiments, numerical simulations, and from studies utilizing both experimental and modeling methods. It is well documented that downwind turbines in multi-Megawatt wind farms often produce less power than upwind turbine rows. These wake-induced power losses have been estimated from 5% to up to 40% depending on the turbine operating settings (e.g., thrust coefficient), number of turbine rows, turbine size (e.g., rotor diameter and hub-height), wind farm terrain, and atmospheric flow conditions (e.g., ambient wind speed, turbulence, and atmospheric stability). Early work by Elliott and Cadogan suggested that power data for different turbulent conditions be segregated to distinguish the effects of turbulence on wind farm power production. This may be especially important for downwind turbines within wind farms, as chaotic and turbulent wake flows increase stress on downstream turbines. Impacts of stability on turbine wakes and power production have been examined for a flat terrain, moderate size (43 turbines) wind farm in Minnesota and for an offshore, 80 turbine wind farm off the coast of Denmark. Conzemius found it difficult to distinguish wakes (i.e., downwind velocity deficits) when the atmosphere was convective as large amounts of scatter were present in the turbine nacelle wind speed data. This suggested that high levels of turbulence broke-up the wake via large buoyancy effects, which are generally on the order of 1 km in size. On the other hand, they found pronounced wake effects when the atmosphere was very stable and turbulence was either suppressed or the length scale was reduced as turbulence in this case was mechanically

  20. Peak Wind Tool for General Forecasting

    Science.gov (United States)

    Barrett, Joe H., III

    2010-01-01

    again by six years, from October 1996 to April 2002, by interpolating 1000-ft sounding data to 100-ft increments. The Phase II developmental data set included observations for the cool season months of October 1996 to February 2007. The AMU calculated 68 candidate predictors from the XMR soundings, to include 19 stability parameters, 48 wind speed parameters and one wind shear parameter. Each day in the data set was stratified by synoptic weather pattern, low-level wind direction, precipitation and Richardson Number, for a total of 60 stratification methods. Linear regression equations, using the 68 predictors and 60 stratification methods, were created for the tool's three forecast parameters: the highest peak wind speed of the day (PWSD), 5-minute average speed at the same time (A WSD), and timing of the PWSD. For PWSD and A WSD, 30 Phase II methods were selected for evaluation in the verification data set. For timing of the PWSD, 12 Phase\\I methods were selected for evaluation. The verification data set contained observations for the cool season months of March 2007 to April 2009. The data set was used to compare the Phase I and II forecast methods to climatology, model forecast winds and wind advisories issued by the 45 WS. The model forecast winds were derived from the 0000 and 1200 UTC runs of the 12-km North American Mesoscale (MesoNAM) model. The forecast methods that performed the best in the verification data set were selected for the Phase II version of the tool. For PWSD and A WSD, linear regression equations based on MesoNAM forecasts performed significantly better than the Phase I and II methods. For timing of the PWSD, none of the methods performed significantly bener than climatology. The AMU then developed the Microsoft Excel and MIDDS GUls. The GUIs display the forecasts for PWSD, AWSD and the probability the PWSD will meet or exceed 25 kt, 35 kt and 50 kt. Since none of the prediction methods for timing of the PWSD performed significantly better

  1. Modelling the Variability of the Wind Energy Resource on Monthly and Seasonal Timescales

    Science.gov (United States)

    Alonzo, Bastien; Ringkjøb, Hans-Kristian; Jourdier, Benedicte; Drobinski, Philippe; Plougonven, Riwal; Tankov, Peter

    2016-04-01

    We study the variability of the wind energy resource in France on monthly to seasonal timescales. On such long-term timescales, the variability of the surface wind speed is strongly influenced by the large-scale situation of the atmosphere. As an example variations in the position of the storm track west of France directly impact surface wind in the North of France in autumn and winter. We investigate the relationship between the large scale circulation and the surface wind speed, summarizing the former by a principal component analysis, so that the large-scale mass distribution is described by a small set of coefficients. We then apply a multi polynomial relationship to model the monthly and seasonal distribution of surface wind speeds given the knowledge of these few coefficients. Different methods for this reconstruction are assessed. While the first attempts to reconstruct the wind with a daily resolution, the three others directly aim at reconstructing the distribution of the wind, assuming it is well described as a Weibull distribution : One is based on the reconstruction of 3 moments of this theoretical distribution, another is based on the reconstruction of two percentiles, and the last one is based on the direct reconstruction of the shape and scale parameter of the Weibull distribution. The last two methods show good performance and better skills to reproduce the monthly and seasonal distribution of the wind speed with respect to the climatology. We then apply those methods to seasonal forecasts from the European Center for Medium-range Weather Forecasts (ECMWF) in an attempt of forecasting the monthly and seasonal distribution of the surface wind speed. For one month time-horizon, the forecasting performance is superior to climatology.

  2. Remote sensing used for power curves

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Ejsing Jørgensen, Hans; Schmidt Paulsen, Uwe

    2008-01-01

    Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the power standard deviat...

  3. Nonlinear Responses of Oceanic Temperature to Wind Stress Anomalies in Tropical Pacific and Indian Oceans:A Study Based on Numerical Experiments with an OGCM

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    As a highly nonlinear dynamic system, oceanic general circulation models (OGCMs) usually exhibit nonlinear responses to prescribed wind stress forcing. To explore mechanisms for these nonlinear responses, we designed and conducted three idealized numerical experiments with an OGCM with modifi ed wind stress forcing. In the experiments, the climatological mean wind stress was identical, and the only diff erences in external forcing were wind stress anomalies. The wind anomalies were set to zero in a control run, and the observed wind stress anomalies with and without reversed signs were superimposed on the mean climatology in two sensitivity experiments. Forced by the prescribed wind stress anomalies in sensitivity runs, the OGCM well reproduced the El Ni˜no–Southern Oscillation (ENSO) and the Pacifi c and Indian Ocean Dipole (IOD) in the Indian Ocean, as well as the asymmetry between positive and negative phases of these modes. Relative to the control run, the two sensitivity runs exhibited almost identical changes in the mean climate state, although the wind stress anomalies were reversed in these two experiments. Thus, it was concluded that the asymmetry of wind stress anomalies contributes only slightly to the mean state changes and ocean internal dynamics was the main contributor. Further heat budget analysis suggested that nonlinear temperature advection terms, including both mean advection and perturbed advection, favor the ENSO/IOD rectifi ed eff ect on the mean state.

  4. U.S. West Coast MODIS Aqua High Resolution SST Climatology Fields (July 2002 - March 2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This suite of CHLA and SST climatology and anomaly data products are derived from daily, 0.0125 degree x 0.0125 degree, MODIS Aqua CHLA and SST fields that cover the...

  5. U.S. West Coast MODIS Aqua High Resolution CHLA Climatology Fields (July 2002 - March 2014)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This suite of CHLA and SST climatology and anomaly data products are derived from daily, 0.0125 degree x 0.0125 degree, MODIS Aqua CHLA and SST fields that cover the...

  6. Aspectos de la climatología del estado de México

    Directory of Open Access Journals (Sweden)

    Ernesto Jáuregui Ostos

    1981-01-01

    Full Text Available The weather systems affecting the State of Mexico are discussed. The main climatological variables are examined for this State located in central Mexico especially those affecting crops grown in this part of Mexico, such as precipitation variability, temperature, frequency of hail, thunder stormes, freezing temperatures etc.

  7. Analysis of freshwater flux climatology over the Indian Ocean using the HOAPS data

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Schulz, J.

    to the lack of in-situ measurements. The climatology and the annual cycle of the freshwater flux over the IO are examined using the newly available Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data (HOAPS). This data set has been derived from...

  8. A global climatology for equatorial plasma bubbles in the topside ionosphere

    Directory of Open Access Journals (Sweden)

    L. C. Gentile

    2006-03-01

    Full Text Available We have developed a global climatology of equatorial plasma bubble (EPB occurrence based on evening sector plasma density measurements from polar-orbiting Defense Meteorological Satellite Program (DMSP spacecraft during 1989-2004. EPBs are irregular plasma density depletions in the post-sunset ionosphere that degrade communication and navigation signals. More than 14400 EPBs were identified in ~134000 DMSP orbits. DMSP observations basically agree with Tsunoda's (1985 hypothesis that EPB rates peak when the terminator is aligned with the Earth's magnetic field, but there are also unpredicted offsets in many longitude sectors. We present an updated climatology for the full database from 1989-2004 along with new plots for specific phases of the solar cycle: maximum 1989-1992 and 1999-2002, minimum 1994-1997, and transition years 1993, 1998, and 2003. As expected, there are significant differences between the climatologies for solar maximum and minimum and between the two solar maximum phases as well. We also compare DMSP F12, F14, F15, and F16 observations at slightly different local times during 2000-2004 to examine local time effects on EPB rates. The global climatologies developed using the DMSP EPB database provide an environmental context for the long-range prediction tools under development for the Communication/Navigation Outage Forecasting System (C/NOFS mission.

  9. Trends in the Indian Ocean Climatology due to anthropogenic induced global warming

    CSIR Research Space (South Africa)

    Meyer, AA

    2009-09-01

    Full Text Available clearly show that due to global warming the South West Indian Ocean Climatology has been changing and that this changing trend will continue into the future as global warming continues. The impacts of regional oceanic climate change on the regions coastal...

  10. A Wildfire-relevant climatology of the convective environment of the United States

    Science.gov (United States)

    Brian E. Potter; Matthew A. Anaya

    2015-01-01

    Convective instability can influence the behaviour of large wildfires. Because wildfires modify the temperature and moisture of air in their plumes, instability calculations using ambient conditions may not accurately represent convective potential for some fire plumes. This study used the North American Regional Reanalysis to develop a climatology of the convective...

  11. Assessment of the present and future offshore wind power potential: a case study in a target territory of the Baltic Sea near the Latvian coast.

    Science.gov (United States)

    Lizuma, Lita; Avotniece, Zanita; Rupainis, Sergejs; Teilans, Artis

    2013-01-01

    Offshore wind energy development promises to be a significant domestic renewable energy source in Latvia. The reliable prediction of present and future wind resources at offshore sites is crucial for planning and selecting the location for wind farms. The overall goal of this paper is the assessment of offshore wind power potential in a target territory of the Baltic Sea near the Latvian coast as well as the identification of a trend in the future wind energy potential for the study territory. The regional climate model CLM and High Resolution Limited Area Model (Hirlam) simulations were used to obtain the wind climatology data for the study area. The results indicated that offshore wind energy is promising for expanding the national electricity generation and will continue to be a stable resource for electricity generation in the region over the 21st century.

  12. Assessment of the Present and Future Offshore Wind Power Potential: A Case Study in a Target Territory of the Baltic Sea Near the Latvian Coast

    Directory of Open Access Journals (Sweden)

    Lita Lizuma

    2013-01-01

    Full Text Available Offshore wind energy development promises to be a significant domestic renewable energy source in Latvia. The reliable prediction of present and future wind resources at offshore sites is crucial for planning and selecting the location for wind farms. The overall goal of this paper is the assessment of offshore wind power potential in a target territory of the Baltic Sea near the Latvian coast as well as the identification of a trend in the future wind energy potential for the study territory. The regional climate model CLM and High Resolution Limited Area Model (Hirlam simulations were used to obtain the wind climatology data for the study area. The results indicated that offshore wind energy is promising for expanding the national electricity generation and will continue to be a stable resource for electricity generation in the region over the 21st century.

  13. Ensemble Data Assimilation of Wind and Photovoltaic Power Information in the Convection-permitting High-Resolution Model COSMO-DE

    Science.gov (United States)

    Declair, Stefan; Saint-Drenan, Yves-Marie; Potthast, Roland

    2016-04-01

    radiances, radar reflectivities or GPS slant delays strongly increases. The numerous wind farm and PV plants installed in Germany potentially represent a dense meteorological network assessing irradiation and wind speed through their power measurements. The accuracy of the NWP data may thus be enhanced by extending the observations in the assimilation by this new source of information. Wind power data can serve as indirect measurements of wind speed at hub height. The impact on the NWP model is potentially interesting since conventional observation network lacks measurements in this part of the PBL. Photovoltaic power plants can provide information on clouds, aerosol optical depth or low stratus in terms of remote sensing: the power output is strongly dependent on perturbations along the slant between sun position and PV panel. Additionally, since the latter kind of data is not limited to the vertical column above or below the detector. It may thus complement satellite data and compensate weaknesses in the radiation scheme. In this contribution, the DA method (Local Ensemble Transform Kalman Filter, LETKF) is shortly sketched. Furthermore, the computation of the model power equivalents is described and first assimilation results are presented and discussed.

  14. Coastal Upwelling and Deep Fog: 50-year Worldwide Climatology

    Science.gov (United States)

    Koracin, D. R.

    2015-12-01

    An analysis is presented of the marine fog distribution based upon the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) ship observations taken during 1950-2007. Deep fog occurrence is reported in routine weather reports that are encoded in an ICOADS ship observation. Occurrence is estimated by the number of deep fog observations divided by the total present weather observations in a one-degree area centered on latitude and longitude grid point intersections. The mean fog occurrence for the summer (June-July-August) 1950-2007 was computed for each one degree point for the world. There are five major world locations with coastal SST minimums due to wind driven upwelling. Four of these are during the local summer on the eastern side of a semi-permanent anticyclone on eastern sides of northern and southern mid-latitudes of the Pacifica and the Atlantic. The fifth is during the SW monsoon in the Indian Ocean. For all five of these locations, the deep fog occurrence is at maximum during the upwelling season, with the greatest occurrences concentrated along the coast and isolated over the SST minimum. For the five coastal fog maxima, the greatest and longest duration occurrence along coast occurrence is associated with the coldest sea surface temperature and longest along coast occurrence, which is along N. California- S. Oregon. In contrast, the lowest occurrence of fog and the least along coast occurrence is associated with the warmest sea surface temperatures and least along coast occurrence along the SE Arabian Peninsula. The remaining three zones, Peru-Chile, NW Africa, and SW Africa are between the two extremes in fog occurrence, along coast coverage and sea surface temperature. Peru-Chile is more complex than the others as the Peru upwelling and fog appears the more dominant although ship observations are sparse along Chile.

  15. Wind engineering in Africa

    NARCIS (Netherlands)

    Wisse, J.A.; Stigter, C.J.

    2007-01-01

    The International Association for Wind Engineering (IAWE) has very few contacts in Africa, the second-largest continent. This paper reviews important wind-related African issues. They all require data on wind climate, which are very sparse in Africa. Wind engineering in Africa can assist in collecti

  16. Emergency wind erosion control

    Science.gov (United States)

    February through May is the critical time for wind erosion in Kansas, but wind erosion can happen any time when high winds occur on smooth, wide fields with low vegetation and poor soil structure. The most effective wind erosion control is to ensure a protective cover of residue or growing crop thro...

  17. Qualified temperature, salinity and dissolved oxygen climatologies in a changing Adriatic Sea

    Directory of Open Access Journals (Sweden)

    M. Lipizer

    2014-02-01

    Full Text Available An updated climatology, based on a comprehensive dataset (1911–2009 of temperature, salinity and dissolved oxygen, has been produced for the whole Adriatic Sea with the Variational Inverse Method using the DIVA software. Climatological maps were produced at 26 levels and validated with Ordinary Cross Validation and with real vs. synthetic Temperature–Salinity diagram intercomparison. The concept of Climatology–Observation Misfit (COM has been introduced as an estimate of the physical variability associated with the climatological structures. In order to verify the temporal stability of the climatology, long-term variability has been investigated in the Mid Adriatic and the South Adriatic Pits, regarded as the most suitable records of possible long-term changes. Compared with previous climatologies, this study reveals a surface temperature rise (up to 2 °C, a clear deep dissolved oxygen minimum in the South Adriatic Gyre and a bottom summer oxygen minimum in the North Adriatic. Below 100 m all properties profoundly differ between the Middle and the South Adriatic. The South Adriatic Pit clearly shows the remote effects of the Eastern Mediterranean Transient, while no effect is observed in Middle Adriatic Pits. The deepest part of the South Adriatic seems now to be significantly saltier (+0.18 since the period 1911–1914, with an increase of +0.018 decade−1 since the late 1940s and warmer (+0.54 °C since 1911–1914, even though a long-term temperature trend could not be statistically demonstrated. Conversely, the Middle Adriatic Pits present a long-term increase in apparent oxygen utilisation (+0.77 mL L−1 since 1911–1914, with a constant increase of +0.2 mL L−1 decade−1 after the 1970s.

  18. Climatology of middle atmospheric water vapour above the ALOMAR observatory in northern Norway

    Directory of Open Access Journals (Sweden)

    K. Hallgren

    2012-12-01

    Full Text Available We have been observing the water vapour line at 22.235 GHz above ALOMAR in northern Norway (69° N, 16° E since early 1996 with ground-based microwave spectrometers (WASPAM and cWASPAM and will here describe a climatology based on these observations. Maintenance, different spectrometers and upgrades of the hardware have slightly changed the instruments. Therefore great care has been taken to make sure the different datasets are compatible with each other. In order to maximise the sensitivity at high altitude for the older instrument a long integration time (168 h was chosen. The complete dataset was thereafter recompiled into a climatology which describes the yearly variation of water vapour at polar latitudes on a weekly basis. The atmosphere is divided into 16 layers between 40–80 km, each 2.5 km thick. The dataset, spanning 15 yr from 1996 to 2010, enabled us to investigate the long-term behaviour of water vapour at these latitudes. By comparing the measurements from every year to the climatological mean we were also able to look for indications of trends in the dataset at different altitudes during the time period of our observations. In general there is a weak negative trend which differs slightly at different altitudes. There are however no drifts in the annual variation of water vapour from the point of view of onset of summer and winter. We compare our climatology to the reference water vapour profiles from AFGL, a free and easy accessible reference atmosphere. There are strong deviations between our observations and the reference profile, therefore we publish our climatological dataset in a table in the paper.

  19. Abnormal Shape Mould Winding

    Institute of Scientific and Technical Information of China (English)

    Fu Hongya; Wang Xianfeng; Han Zhenyu; Fu Yunzhong

    2007-01-01

    A theory of composite material patch winding is proposed to determine the winding trajectory with a meshed data model. Two different conditions are considered in this study. One is Bridge condition on the concave surface and the other is Slip line condition in the process of patch winding. This paper presents the judgment principles and corresponding solutions by applying differential geometry theory and space geometry theory. To verify the feasibility of the patch winding method, the winding control code is programmed. Furthermore, the winding experiments on an airplane inlet and a vane are performed. From the experiments, it shows that the patch winding theory has the advantages of flexibility, easy design and application.

  20. Solar activity variations of nocturnal thermospheric meridional winds over Indian longitude sector

    Science.gov (United States)

    Madhav Haridas, M. K.; Manju, G.; Arunamani, T.

    2016-09-01

    The night time F-layer base height information from ionosondes located at two equatorial stations Trivandrum (TRV 8.5°N, 77°E) and Sriharikota (SHAR 13.7°N, 80.2°E) spanning over two decades are used to derive the climatology of equatorial nocturnal Thermospheric Meridional Winds (TMWs) prevailing during High Solar Activity (HSA) and Low Solar Activity (LSA) epochs. The important inferences from the analysis are 1) Increase in mean equatorward winds observed during LSA compared to HSA during pre midnight hours; 25 m/s for VE (Vernal Equinox) and 20 m/s for SS (Summer Solstice), AE (autumnal Equinox) and WS (Winter Solstice). 2) Mean wind response to Solar Flux Unit (SFU) is established quantitatively for all seasons for pre-midnight hours; rate of increase is 0.25 m/s/SFU for VE, 0.2 m/s/SFU for SS and WS and 0.08 m/s/SFU for AE. 3) Theoretical estimates of winds for the two epochs are performed and indicate the role of ion drag forcing as a major factor influencing TMWs. 4) Observed magnitude of winds and rate of flux dependencies are compared to thermospheric wind models. 5) Equinoctial asymmetry in TMWs is observed for HSA at certain times, with more equatorward winds during AE. These observations lend a potential to parameterize the wind components and effectively model the winds, catering to solar activity variations.

  1. A Peak Wind Probability Forecast Tool for Kennedy Space Center and Cape Canaveral Air Force Station

    Science.gov (United States)

    Crawford, Winifred; Roeder, William

    2008-01-01

    This conference abstract describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida. The peak winds are an important forecast element for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a short-range peak-wind forecast tool to assist in forecasting LCC violatioas.The tool will include climatologies of the 5-minute mean end peak winds by month, hour, and direction, and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  2. Resolving Nonstationary Spectral Information in Wind Speed Time Series Using the Hilbert-Huang Transform

    DEFF Research Database (Denmark)

    Vincent, Claire Louise; Giebel, Gregor; Pinson, Pierre

    2010-01-01

    This work is motivated by the observation that large-amplitude wind fluctuations on temporal scales of 1–10 h present challenges for the power management of large offshore wind farms. Wind fluctuations on these scales are analyzed at a meteorological measurement mast in the Danish North Sea using...... such as the Fourier transform. The Hilbert–Huang transform is a local method based on a nonparametric and empirical decomposition of the data followed by calculation of instantaneous amplitudes and frequencies using the Hilbert transform. The Hilbert–Huang transformed 4-yr time series is averaged and summarized...... to show climatological patterns in the relationship between wind variability and time of day. First, by integrating the Hilbert spectrum along the frequency axis, a scalar time series representing the total variability within a given frequency range is calculated. Second, by calculating average spectra...

  3. Wind power. [electricity generation