Impact of active and break wind spells on the demand-supply balance in wind energy in India

Science.gov (United States)

Kulkarni, Sumeet; Deo, M. C.; Ghosh, Subimal

2018-02-01

With an installed capacity of over 19,000 MW, the wind power currently accounts for almost 70% of the total installed capacity among the renewable energy sector in India. The extraction of wind power mainly depends on prevailing meteorology which is strongly influenced by monsoon variability. The monsoon season is characterized by significant fluctuations in between periods of wet and dry spells. During the dry spells, the demand for power from agriculture and cooling equipment increases, whereas during the wet periods, such demand reduces, although, at the same time, the power supply increases because of strong westerly winds contributing to an enhanced production of wind energy. At this backdrop, we aim to assess the impact of intra-seasonal wind variability on the balance of energy supply and demand during monsoon seasons in India. Further, we explore the probable cause of wind variability by relating it to El Nino events. It is observed that the active and break phases in wind significantly impact the overall wind potential output. Although the dry spells are generally found to reduce the overall wind potential, their impact on the potential seems to have declined after the year 2000. The impact of meteorological changes on variations in wind power studied in this work should find applications typically in taking investment decisions on conventional generation facilities, like thermal, which are currently used to maintain the balance of power supply and demand.

How East Asian westerly jet's meridional position affects the summer rainfall in Yangtze-Huaihe River Valley?

Science.gov (United States)

Wang, Shixin; Zuo, Hongchao; Zhao, Shuman; Zhang, Jiankai; Lu, Sha

2017-03-01

Existing studies show that the change in the meridional position of East Asian westerly jet (EAWJ) is associated with rainfall anomalies in Yangtze-Huaihe River Valley (YHRV) in summer. However, the dynamic mechanism has not been resolved yet. The present study reveals underlying mechanisms for this impact for early summer and midsummer, separately. Mechanism1: associated with EAWJ's anomalously southward displacement, the 500-hPa westerly wind over YHRV is strengthened through midtropospheric horizontal circulation anomalies; the westerly anomalies are related to the formation of warm advection anomalies over YHRV, which cause increased rainfall through adiabatic ascent motion and convective activities; the major difference in these processes between early summer and midsummer is the midtropospheric circulation anomaly pattern. Mechanism 2: associated with EAWJ's anomalously southward displacement, the large day-to-day variability of midtropospheric temperature advection in midlatitudes is displaced southward by the jet's trapping transient eddies; this change enhances the day-to-day variability of temperature advection over YHRV, which in turn causes the increased rainfall in most part of YHRV through "lower-bound effect" (rainfall amount can not become negative); there is not much difference in these processes between early summer and midsummer.

On wake modeling, wind-farm gradients and AEP predictions at the Anholt wind farm

DEFF Research Database (Denmark)

Pena Diaz, Alfredo; Hansen, Kurt Schaldemose; Ott, Søren

2017-01-01

of the mesoscale simulations and supervisory control and data acquisition (SCADA), we show that for westerly flow in particular, there is a clear horizontal wind-speed gradient over the wind farm. We also use the mesoscale simulations to derive the undisturbed inflow conditions that are coupled with three commonly....... When looking at westerly flow wake cases, where the impact of the horizontal wind-speed gradient on the power of the undisturbed turbines is largest, the wake models agree with the SCADA fairly well; when looking at a southerly flow case, where the wake losses are highest, the wake models tend...... to underestimate the wake loss. With the mesoscale-wake model setup, we are also able to estimate the capacity factor of the wind farm rather well when compared to that derived from the SCADA. Finally, we estimate the uncertainty of the wake models by bootstrapping the SCADA. The models tend to underestimate...

Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies

Directory of Open Access Journals (Sweden)

J. C. Stager

2012-05-01

Full Text Available The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ∼1400–1200 cal yr BP, decreased until ∼950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ∼600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming.

Extreme pressure differences at 0900 NZST and winds across New Zealand

Science.gov (United States)

Salinger, M. James; Griffiths, Georgina M.; Gosai, Ashmita

2005-07-01

Trends in extremes in station daily sea-level pressure differences at 0900 NZST are examined, and extreme daily wind gusts, across New Zealand, since the 1960s. Annual time series were examined (with indices of magnitude and frequency over threshold percentiles) from the daily indices selected. These follow from earlier indices of normalized monthly mean sea-level pressure differences between station pairs, except the daily indices are not normalized. The frequency statistics quantify the number of extreme zonal (westerly and easterly), or extreme meridional (southerly or northerly), pressure gradient events. The frequency and magnitude of extreme westerly episodes has increased slightly over New Zealand, with a significant increase in the westerly extremes to the south of New Zealand. In contrast, the magnitude and frequency of easterly extremes has decreased over New Zealand, but increased to the south, with some trends weakly significant. The frequency and magnitude of daily southerly extremes has decreased significantly in the region.Extreme daily wind gust events at key climate stations in New Zealand and at Hobart, Australia, are highly likely to be associated with an extreme daily pressure difference. The converse was less likely to hold: extreme wind gusts were not always observed on days with extreme daily pressure difference, probably due to the strong influence that topography has on localized station winds. Significant correlations exist between the frequency indices and both annual-average mean sea-level pressures around the Australasian region and annual-average sea surface temperature (SST) anomalies in the Southern Hemisphere. These correlations are generally stronger for indices of extreme westerly or extreme southerly airflows. Annual-average pressures in the Tasman Sea or Southern Ocean are highly correlated to zonal indices (frequency of extreme westerlies). SST anomalies in the NINO3 region or on either side of the South Island are

Relationships between the West Asian subtropical westerly jet and summer precipitation in northern Xinjiang

Science.gov (United States)

Zhao, Yong; Wang, MinZhong; Huang, AnNing; Li, HongJun; Huo, Wen; Yang, Qing

2014-05-01

The relation between the spatial and temporal variations of the West Asian subtropical westerly jet (WASWJ) and the summer precipitation in northern Xinjiang has been explored using the NCEP/NCAR reanalysis data and the summer precipitation data at 43 stations in northern Xinjiang during 1961 to 2007. Results show that the position of the WASWJ is more important than its strength in influencing the summer precipitation in northern Xinjiang. When the jet position is further south, the anomalous southwesterly flow crossing the Indian subcontinent along the southern foothill of the Tibetan Plateau is favorable for the southwestward warm and wet air penetrating from low latitudes into Central Asia and northern Xinjiang and more rainfall formation. Further analysis shows that the interannual variations of the jet position are well correlated with the Arctic Oscillation (AO). In the weak AO years, the middle to upper troposphere becomes colder than normal and results in an anomalous cyclonic circulation at 200 hPa over Western and Central Asia, which enhances the westerly wind over middle and low latitudes and leads to the WASWJ located further south.

Structure and precursors of the 1992 / 93 drought in KwaZulu-Natal ...

African Journals Online (AJOL)

The historical context and potential causes and structure of the 1992/93 drought in KwaZulu-Natal are analysed using NCEP reanalysis data. The analysis indicates that increased westerly winds with surface marine lows and continental highs prevailed over Southern Africa. Anomalous divergence and subsidence occur ...

Influence of Westerly Wind Events stochasticity on El Niño amplitude: the case of 2014 vs. 2015

Science.gov (United States)

Puy, Martin; Vialard, Jérôme; Lengaigne, Matthieu; Guilyardi, Eric; DiNezio, Pedro N.; Voldoire, Aurore; Balmaseda, Magdalena; Madec, Gurvan; Menkes, Christophe; Mcphaden, Michael J.

2017-10-01

The weak El Niño of 2014 was preceded by anomalously high equatorial Pacific Warm Water Volume (WWV) and strong Westerly Wind Events (WWEs), which typically lead to record breaking El Nino, like in 1997 and 2015. Here, we use the CNRM-CM5 coupled model to investigate the causes for the stalled El Niño in 2014 and the necessary conditions for extreme El Niños. This model is ideally suited to study this problem because it simulates all the processes thought to be critical for the onset and development of El Niño. It captures El Niño preconditioning by WWV, the WWEs characteristics and their deterministic behaviour in response to warm pool displacements. Our main finding is, that despite their deterministic control, WWEs display a sufficiently strong stochastic component to explain the distinct evolutions of El Niño in 2014 and 2015. A 100-member ensemble simulation initialized with early-spring equatorial conditions analogous to those observed in 2014 and 2015 demonstrates that early-year elevated WWV and strong WWEs preclude the occurrence of a La Niña but lead to El Niños that span the weak (with few WWEs) to extreme (with many WWEs) range. Sensitivity experiments confirm that numerous/strong WWEs shift the El Niño distribution toward larger amplitudes, with a particular emphasis on summer/fall WWEs occurrence which result in a five-fold increase of the odds for an extreme El Niño. A long simulation further demonstrates that sustained WWEs throughout the year and anomalously high WWV are necessary conditions for extreme El Niño to develop. In contrast, we find no systematic influence of easterly wind events (EWEs) on the El Niño amplitude in our model. Our results demonstrate that the weak amplitude of El Niño in 2014 can be explained by WWEs stochastic variations without invoking EWEs or remote influences from outside the tropical Pacific and therefore its peak amplitude was inherently unpredictable at long lead-time.

Radioactive material defense construction using wind fan system against nuclear fallout in the aspect of nano-scopic dispersion

International Nuclear Information System (INIS)

Woo, Tae Ho

2012-01-01

Highlights: ► A realistic radiation protection system using aerodynamics is suggested. ► Manual formation procedure is constructed by this modeling. ► Chemical and natural accidents by wind fan are applicable. ► Nuclear disaster is avoided by national defense system. ► A sample case is realistically modeled. -- Abstract: Radioactive fallout defense system (RFDS) is suggested against possible nuclear accidents. A procedure consisting of several stages is considered. In particular, the dispersion of radioactive material is investigated for the case of wind fan operation where the radioactive molecules are considered as nano-scopic material. The modeling is done for one country dealing with a possible nuclear accident in another country. This study is thus applicable to regions where westerlies are prevailing. An aerodynamic fan analysis is performed. The incoming free wind stream is characterized by random sampling in Monte-Carlo simulation. The velocity of the fan is a critical aspect of the model. This model is applicable for volcanic ashes, nuclear bomb fallout, chemical material dispersion, and any other material combined with airflow. In addition, this fan could be studied, with nano-scale considerations, by a multi-scale technique.

On wake modeling, wind-farm gradients, and AEP predictions at the Anholt wind farm

Directory of Open Access Journals (Sweden)

A. Peña

2018-04-01

Full Text Available We investigate wake effects at the Anholt offshore wind farm in Denmark, which is a farm experiencing strong horizontal wind-speed gradients because of its size and proximity to land. Mesoscale model simulations are used to study the horizontal wind-speed gradients over the wind farm. From analysis of the mesoscale simulations and supervisory control and data acquisition (SCADA, we show that for westerly flow in particular, there is a clear horizontal wind-speed gradient over the wind farm. We also use the mesoscale simulations to derive the undisturbed inflow conditions that are coupled with three commonly used wake models: two engineering approaches (the Park and G. C. Larsen models and a linearized Reynolds-averaged Navier–Stokes approach (Fuga. The effect of the horizontal wind-speed gradient on annual energy production estimates is not found to be critical compared to estimates from both the average undisturbed wind climate of all turbines' positions and the undisturbed wind climate of a position in the middle of the wind farm. However, annual energy production estimates can largely differ when using wind climates at positions that are strongly influenced by the horizontal wind-speed gradient. When looking at westerly flow wake cases, where the impact of the horizontal wind-speed gradient on the power of the undisturbed turbines is largest, the wake models agree with the SCADA fairly well; when looking at a southerly flow case, where the wake losses are highest, the wake models tend to underestimate the wake loss. With the mesoscale-wake model setup, we are also able to estimate the capacity factor of the wind farm rather well when compared to that derived from the SCADA. Finally, we estimate the uncertainty of the wake models by bootstrapping the SCADA. The models tend to underestimate the wake losses (the median relative model error is 8.75 % and the engineering wake models are as uncertain as Fuga. These results are specific for

The influence of tropical wind data on the analysis and forecasts of the GLAS GCM for the Global Weather Experiment

Science.gov (United States)

Paegle, J.; Baker, W. E.

1985-01-01

Several densities of tropical divergent wind data were included in a fourth-order GCM to examine the effects on the accuracy of the model predictions. The experiments covered assimilation of all available tropical wind data, no tropical wind data between 20 deg N and 20 deg S, only westerly tropical wind data and only easterly tropical wind data. The predictions were all made for the 200 mb upper troposphere. Elimination of tropical data produced excessively strong upper tropospheric westerlies which in turn amplified the globally integrated rotational flow kinetic energy by around 10 percent and doubled the global divergent flow kinetic energy. Retaining only easterly wind data, ameliorated most of the error. Inclusion of all the tropical wind data however, did not lead to overall positive effects, as the data were linked to tropical wave energetics and ageostrophic winds which were already assimilated in the model.

Upper wind observing systems used for meteorological operations

Directory of Open Access Journals (Sweden)

J. Nash

Full Text Available Methods of upper wind measurements used in operational meteorology have been reviewed to provide guidance to those developing wind profiler radar systems. The main limitations of the various methods of tracking weather balloons are identified using results from the WMO radiosonde comparisons and additional tests in the United Kingdom. Costs associated with operational balloon measurements are reviewed. The sampling and quality of operational aircraft wind observations are illustrated with examples from the ASDAR system. Measurement errors in horizontal winds are quantified wherever possible. When tracking equipment is functioning correctly, random errors in southerly and westerly wind component measurements from aircraft and weather balloons are usually in the range 0.5-2 m s^-1.

Representation of the tropical stratospheric zonal wind in global atmospheric reanalyses

Directory of Open Access Journals (Sweden)

Y. Kawatani

2016-06-01

Full Text Available This paper reports on a project to compare the representation of the monthly-mean zonal wind in the equatorial stratosphere among major global atmospheric reanalysis data sets. The degree of disagreement among the reanalyses is characterized by the standard deviation (SD of the monthly-mean zonal wind and this depends on latitude, longitude, height, and the phase of the quasi-biennial oscillation (QBO. At each height the SD displays a prominent equatorial maximum, indicating the particularly challenging nature of the reanalysis problem in the low-latitude stratosphere. At 50–70 hPa the geographical distributions of SD are closely related to the density of radiosonde observations. The largest SD values are over the central Pacific, where few in situ observations are available. At 10–20 hPa the spread among the reanalyses and differences with in situ observations both depend significantly on the QBO phase. Notably the easterly-to-westerly phase transitions in all the reanalyses except MERRA are delayed relative to those directly observed in Singapore. In addition, the timing of the easterly-to-westerly phase transitions displays considerable variability among the different reanalyses and this spread is much larger than for the timing of the westerly-to-easterly phase changes. The eddy component in the monthly-mean zonal wind near the Equator is dominated by zonal wavenumber 1 and 2 quasi-stationary planetary waves propagating from midlatitudes in the westerly phase of the QBO. There generally is considerable disagreement among the reanalyses in the details of the quasi-stationary waves near the Equator. At each level, there is a tendency for the agreement to be best near the longitude of Singapore, suggesting that the Singapore observations act as a strong constraint on all the reanalyses. Our measures of the quality of the reanalysis clearly show systematic improvement over the period considered (1979–2012. The SD among the reanalysis

Wind energy potential in India

International Nuclear Information System (INIS)

Rangarajan, S.

1995-01-01

Though located in the tropics, India is endowed with substantial wind resources because of its unique geographical location which gets fully exposed to both the south-west and north-east monsoon winds. The westerly winds of the south-west monsoons provide bulk of the wind potential. Areas with mean annual wind speed exceeding 18 k mph and areas with mean annual power density greater than 140 W/m 2 have been identified using the wind data collected by the wind monitoring project funded by the Ministry of Non-conventional Energy Sources (MNES). Seasonal variations in wind speed at selected locations are discussed as also the frequency distribution of hourly wind speed. Annual capacity factors for 250 kW wind electric generators have been calculated for several typical locations. A good linear correlation has been found between mean annual wind speed and mean annual capacity factor. A method is described for assessing wind potential over an extended region where adequate data is available. It is shown that the combined wind energy potential over five selected areas of limited extent in Gujarat, Andhra Pradesh and Tamil Nadu alone amounts to 22,000 MW under the assumption of 20 per cent land availability for installing wind farms. For a higher percentage of land availability, the potential will be correspondingly higher. (author). 12 refs., 6 figs., 3 tabs

Decadal Patterns of Westerly Winds, Temperatures, Ocean Gyre Circulations and Fish Abundance: A Review

Directory of Open Access Journals (Sweden)

Candace Oviatt

2015-10-01

Full Text Available The purpose of this review is to describe the global scope of the multidecadal climate oscillations that go back at least, through several hundred years. Literature, historic data, satellite data and global circulation model output have been used to provide evidence for the zonal and meridional jet stream patterns. These patterns were predominantly zonal from the 1970s to 1990s and switched since the 1990s to a meridional wind phase, with weakening jet streams forming Rossby waves in the northern and southern hemispheres. A weakened northern jet stream has allowed northerly winds to flow down over the continents in the northern hemisphere during the winter period, causing some harsh winters and slowing anthropogenic climate warming regionally. Wind oscillations impact ocean gyre circulation affecting upwelling strength and pelagic fish abundance with synchronous behavior in sub Arctic gyres during phases of the oscillation and asynchronous behavior in subtropical gyres between the Atlantic and Pacific oceans.

Constraining 20th Century Pacific Trade-Wind Variability Using Coral Mn/Ca

Science.gov (United States)

Sayani, H. R.; Thompson, D. M.; Carilli, J.; Ireland, T. J.; Cobb, K. M.; Atwood, A. R.; Grothe, P. R.; Miller, S. J.; Hitt, N. T.; O'Connor, G.

2017-12-01

Global mean surface temperatures during the 20th century are characterized by multidecadal periods of either accelerated or reduced rates of warming that cannot be explained by external forcings alone. Both observations and modeling studies suggest that the reduced rate of global surface warming during the early-2000s can be largely explained by decadal climate variability in the tropical Pacific, specifically changes in trade-wind strength [e.g. Meehl et al., 2016]. However, the relationship between Pacific trade-wind strength and global surface warming is poorly constrained due to the lack of instrumental wind observations prior to the 1970s. Surface corals are now routinely used to generate records of past sea-surface temperature (SST) change, and have dramatically improved our understanding of oceanic variability in the tropical Pacific. Yet, there are few direct measurements of the atmospheric response to this SST variability. Skeletal Mn/Ca ratios in corals from Tarawa Atoll (1.3˚N, 173˚E) have been shown to track El Niño-related westerly wind events on interannual timescales [Shen et al., 1992], and the strength of Pacific trade winds on decadal timescales [Thompson et al., 2015]. Here, we investigate the utility of this novel wind proxy at Kiritimati Atoll (Christmas Island; 2˚N, 157.5˚W), a site that is hydrographically similar to Tarawa. We use a series of seawater samples collected across the 2015/16 El Niño to characterize and quantify the relationship between westerly wind events and seawater Mn variability around Kiritimati. Anchored by this modern-day calibration, we present a new reconstruction of westerly winds across the late-20thcentury from Kiritimati Atoll. We also assess the reproducibility of coral Mn/Ca across cores collected at varying distances from the lagoon, which represents the primary source of seawater Mn to the reef at our site. Lastly, we discuss the strengths and limitations of this novel proxy, as well as the potential for

Diurnal circulations and their multi-scale interaction leading to rainfall over the South China Sea upstream of the Philippines during intraseasonal monsoon westerly wind bursts

Energy Technology Data Exchange (ETDEWEB)

Park, Myung-Sook; Elsberry, Russell L. [Naval Postgraduate School, Department of Meteorology, Monterey, CA (United States); Ho, Chang-Hoi [Seoul National University, School of Earth and Environmental Sciences, Seoul (Korea, Republic of); Kim, Jinwon [University of California in Los Angeles, Department of Meteorology, Berkeley, CA (United States)

2011-10-15

The morning diurnal precipitation maximum over the coastal sea upstream of the Philippines during intraseasonal westerly wind bursts is examined from observations and numerical model simulations. A well-defined case of precipitation and large-scale circulation over the coastal sea west of the Philippines during 17-27 June 2004 is selected as a representative case. The hypothesis is that the mesoscale diurnal circulation over the Philippines and a large-scale diurnal circulation that is induced by large-scale differential heating over Asian continent and the surrounding ocean interact to produce the offshore precipitation maximum during the morning. Three-hourly combined satellite microwave and infrared rainfall retrievals define the morning rainfall peak during this period, and then later the stratiform rain area extends toward the open sea. A control numerical simulation in which a grid-nudging four-dimensional data assimilation (FDDA) is applied to force the large-scale diurnal circulation represents reasonably well the morning rainfall maximum. An enhanced low-level convergence similar to observations is simulated due to the interaction of the local- and large-scale diurnal circulations. The essential role of the local-scale diurnal circulation is illustrated in a sensitivity test in which the solar zenith angle is fixed at 7 am to suppress this diurnal circulation. The implication for climate diagnosis or modeling of such upstream coastal sea precipitation maxima is that the diurnal variations of both the local- and the large-scale circulations must be taken into consideration. (orig.)

12 CFR 747.603 - Prevailing party.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Prevailing party. 747.603 Section 747.603 Banks... in NCUA Board Adjudications § 747.603 Prevailing party. An eligible applicant may be a “prevailing... dismissed. In appropriate situations an applicant may also have prevailed if the outcome of the proceeding...

Reply to Comment by Xu et al. on "Sr-Nd isotope composition and clay mineral assemblages in eolian dust from the central Philippine Sea over the last 600 kyr: Implications for the transport mechanism of Asian dust" by Seo et al.

Science.gov (United States)

Seo, Inah; Lee, Yong Il; Yoo, Chan Min; Kim, Hyung Jeek; Hyeong, Kiseong

2016-12-01

Against Xu et al. (2016), who argued that East Asian Desert (EAD) dust that traveled on East Asian Winter Monsoon winds dominates over Central Asian Desert (CAD) dust in the Philippine Sea with presentation of additional data, we reconfirm Seo et al.'s (2014) conclusion that CAD dust carried on the Prevailing Westerlies and Trade Winds dominates over EAD dust in overall dust budget of the central Philippine Sea. The relative contribution of dust from EADs and CADs using clay mineral composition should be evaluated with elimination of mineralogical contribution from the volcanic end-member which is enriched in kaolinite and overestimate the contribution of EAD dust.

On the wave forcing of the semi-annual zonal wind oscillation

Science.gov (United States)

Nagpal, O. P.; Raghavarao, R.

1991-01-01

Observational evidence of rather large period waves (23-60 d) in the troposphere/stratosphere, particularly during the winter months, is presented. Wind data collected on a regular basis employing high-altitude balloons and meteorological rockets over the past few years are used. Maximum entropy methods applied to the time series of zonal wind data indicate the presence of 23-60-waves more prominently than shorter-period waves. The waves have substantial amplitudes in the stratosphere and lower mesosphere, often larger than those noted in the troposphere. The mean zonal wind in the troposphere (5-15 km altitude) during December, January, and February exhibits the presence of strong westerlies at latitudes between 8 and 21 deg N.

12 CFR 263.102 - Prevailing party.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Prevailing party. 263.102 Section 263.102 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM RULES... Prevailing party. Only an eligible applicant that prevailed on the merits of an adversary proceeding may...

12 CFR 308.173 - Prevailing party.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Prevailing party. 308.173 Section 308.173 Banks....173 Prevailing party. (a) General rule. An eligible applicant who, following an adversary adjudication has gained victory on the merits in the proceeding is a “prevailing party”. An eligible applicant may...

Financing Educational Facility Construction: Prevailing Wage Litigation.

Science.gov (United States)

Goldblatt, Steven M.; Wood, R. Craig

This chapter presents an up-to-date analysis of prevailing state wage laws that affect educational facility construction or renovation and highlights relevant prevailing wage litigation in many states. Currently, 13 states have no prevailing wage laws for public works. The other 37 states and the District of Columbia do have prevailing wage laws…

Great Historical Events That Were Significantly Affected by the Weather: 7, "Protestant Wind"-"Popish Wind": The Revolusion of 1688 in England.

Science.gov (United States)

Lindgrén, S.; Neumann, J.

1985-06-01

James II, King of England from 1685 to 1688, increasingly antagonized his people by his forced attempts to restore the Catholic faith to a position of eminence in England; many of his actions were contrary to acts passed by earlier Parliaments (he ruled without Parliament most of his reign). Leading dignitaries of the Church of England, of the Protestant nobility, and some of the high officers of the Army and Navy came to the conclusion that the only remedy to the country's ills was to call in William, the Prince of Orange and Chief Magistrate ("Stadholder") of the Netherlands, whose spouse Mary, James' daughter, was, until July 1688, the heir-presumptive to the English crown; the prince himself had a position in the list of succession, bring a nephew of James.Over and above the prince's personal ambitions, it was his conviction and that of several other leading personalities in the Dutch Republic that it was in the vital interest of the Netherlands to influence England's policies, and, in particular, to prevent a line-up of England with the France of Louis XIV, who had hostile designs on the Republic. As long as the danger of a French assault on the Netherlands was imminent, the States-General of the Republic would not authorize the "descent" on England, but when late in September 1688 Louis decided to attack the German States on the Middle-Rhine first, the "descent" gained approval.The peak of the crisis about James' policies in England was reached in summer-early fall of 1688. In the meantime, William assembled a large fleet and force in the Netherlands to "descend" on England, but his sailing was hindered by winds that in September and October blew with nearly total persistence from the westerly quarter. People in England and in the Netherlands were daily watching for weeks the direction of wind. They called the easterly winds "Protestant winds" and the westerly winds "Popish winds." In addition to making possible the invasion, the "Protestant winds" made it

A simple climatology of westerly jet streams in global reanalysis datasets part 1: mid-latitude upper tropospheric jets

Science.gov (United States)

Rikus, Lawrie

2018-04-01

A simple closed contour object identification scheme has been applied to the zonal mean monthly mean zonal wind fields from nine global reanalysis data sets for 31 years of the satellite era (1979-2009) to identify objects corresponding to westerly jet streams. The results cluster naturally into six individual jet streams but only the mid-latitude upper-tropospheric jets are considered here. The time series of the jet properties from all reanalyses are decomposed into seasonal means and anomalies, and correlations between variables are evaluated, with the aim of identifying robust features which can form the basis of evaluation metrics for climate model simulations of the twentieth century. There is substantial agreement between all the reanalyses for all jet properties although there are some systematic differences with particular data sets. Some of the results from the object identification applied to the reanalyses are used in a simple example of a model evaluation score for the zonal mean jet seasonal cycle.

Epistaxis: Prevailing Factors and Treatment

Directory of Open Access Journals (Sweden)

Secchi, Myrian Marajó Dal

2009-12-01

Full Text Available Introduction: The epistaxis is one the most frequent otorhinolaryngologic emergencies in the medical practice. It is a benign affection, but the refractory cases require hospital admission. Objective: To evaluate prevailing factors in patients with epistaxis and treatment. Form of study: Retrospective study. Method: 60 patients with diagnosis of epistaxis were evaluated and they needed hospital admission between 2005 and 2006. Results: The main prevailing factors were: Systemic arterial hypertension 36% (n= 22, trauma 16% (n=10 and coagulopathy 5% (n=3. The treatment was the use of nasal splint: anterior 58% (n=35 and antero-posterior 27% (n=16, the electrocauterization of the identified bloody point 7% (n=4, endoscopic arterial bandage 8% (n=5 in severe epistaxis. For the patients with antero-posterior splint with recurrence of bleeding in the first 24 hours (five patients, after clinical stabilization, an arterial bandage was indicated by endoscopic means; four patients had systemic arterial hypertension and in one patient no prevailing factor was identified. Conclusion: The main associated prevailing factors were systemic arterial hypertension, trauma and coagulopathy. The treatment depends on the type, severity and cause of bleeding, initially the anterior and antero-posterior splint for bleeding control. The early endoscopic arterial bandage is indicated in patients with severe epistaxis and prevailing factors, and prolonged admission and morbidities associated with nasal splint should be avoided.

Temporal and spatial complementarity of wind and solar resources in Lower Silesia (Poland)

Science.gov (United States)

Jurasz, Jakub; Wdowikowski, Marcin; Kaźmierczak, Bartosz; Dąbek, Paweł

2017-11-01

This paper investigates the concept of temporal and spatial complementarity of wind and solar resources in Lower Silesia (south-wester Poland). For the purpose of our research we have used hourly load and energy yield from photovoltaics and wind turbines covering period 2010-2014. In order to assess the spatial complementarity we have divided the considered voivodeship into 74 squared regions with maximal area of 400 km2. The obtained results indicate an existence of temporal complementarity on a monthly time scale and a positive correlation between load and wind generation patterns (also on a monthly time scale). The temporal complementarity for hourly time series in relatively low but has potential to smooth the energy generation curves.

Asian monsoons and aridification response to Paleogene sea retreat and Neogene westerly shielding indicated by seasonality in Paratethys oysters

Science.gov (United States)

Bougeois, Laurie; Dupont-Nivet, Guillaume; de Rafélis, Marc; Tindall, Julia C.; Proust, Jean-Noël; Reichart, Gert-Jan; de Nooijer, Lennart J.; Guo, Zhaojie; Ormukov, Cholponbelk

2018-03-01

Asian climate patterns, characterised by highly seasonal monsoons and continentality, are thought to originate in the Eocene epoch (56 to 34 million years ago - Ma) in response to global climate, Tibetan Plateau uplift and the disappearance of the giant Proto-Paratethys sea formerly extending over Eurasia. The influence of this sea on Asian climate has hitherto not been constrained by proxy records despite being recognised as a major driver by climate models. We report here strongly seasonal records preserved in annual lamina of Eocene oysters from the Proto-Paratethys with sedimentological and numerical data showing that monsoons were not dampened by the sea and that aridification was modulated by westerly moisture sourced from the sea. Hot and arid summers despite the presence of the sea suggest a strong anticyclonic zone at Central Asian latitudes and an orographic effect from the emerging Tibetan Plateau. Westerly moisture precipitating during cold and wetter winters appear to have decreased in two steps. First in response to the late Eocene (34-37 Ma) sea retreat; second by the orogeny of the Tian Shan and Pamir ranges shielding the westerlies after 25 Ma. Paleogene sea retreat and Neogene westerly shielding thus provide two successive mechanisms forcing coeval Asian desertification and biotic crises.

29 CFR 505.3 - Prevailing minimum compensation.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Prevailing minimum compensation. 505.3 Section 505.3 Labor... HUMANITIES § 505.3 Prevailing minimum compensation. (a)(1) In the absence of an alternative determination...)(2) of this section, the prevailing minimum compensation required to be paid under the Act to the...

26 CFR 301.7430-5 - Prevailing party.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Prevailing party. 301.7430-5 Section 301.7430-5... Prevailing party. (a) In general. For purposes of an award of reasonable administrative costs under section... prevailing party only if— (1) The position of the Internal Revenue Service was not substantially justified...

Wind lidar profile measurements in the coastal boundary layer: comparison with WRF modelling

DEFF Research Database (Denmark)

Floors, Rogier; Pena Diaz, Alfredo; Vincent, Claire Louise

2012-01-01

the sensitivity of PBL schemes of mesoscale models to both lower and upper boundary conditions. We therefore run the mesoscale weather research and forecasting (WRF) model using two different roughness descriptions, two different synoptic forcings and two different PBL schemes at two vertical resolutions. When...... in the amount of observed low level jet. The wind speed predicted by WRF does not improve when a higher resolution is used. Therefore, both the inhomogeneous (westerly) and homogeneous (easterly) flow contribute to a large negative bias in the mean wind speed profile at heights between 100 and 200 m....

Effect of fall wind on wind power generation; Furyoku hatsuden ni okeru dashikaze no koka

Energy Technology Data Exchange (ETDEWEB)

Nagai, H [Nihon University, Tokyo (Japan)

1997-11-25

Wind conditions in Arakawa Town, Niigata Prefecture, were surveyed by anemometers and anemoscopes installed at 3 different points, and the data are analyzed to develop the prediction model for investigating possibility of introduction of wind mills there. Outlined herein is power generated by fall wind by comparing predicted power availability with the actual results. In order to investigate possibility of power generation by fall wind, the wind conditions and power availability are simulated using the observed wind condition data. Predicted wind velocity involves a large error at a point where frequency of prevailing wind direction is high, and direction in which average wind velocity is high coincides with direction in which land is slanted at a high slope. Fall wind occurs locally for geographical reasons. Location of the wind mill must be carefully considered, because it is complex, although potentially gives a larger quantity of power. A wind mill of 400kW can produce power of around 600MWh annually, when it is located at the suited site confirmed by the wind condition analysis results. 6 refs., 5 figs., 6 tabs.

Longitudinal differences and inter-annual variations of zonal wind in the tropical stratosphere and troposphere

Science.gov (United States)

Reddy, C. A.; Raghava Reddi, C.

1986-12-01

A quantitative assessment has been made of the longitude-dependent differences and the interannual variations of the zonal wind components in the equatorial stratosphere and troposphere, from the analysis of rocket and balloon data for 1979 and 1980 for three stations near ±8.5° latitude (Ascension Island at 14.4°W, Thumba at 76.9°E and Kwajalein at 67.7°E) and two stations near 21.5° latitude (Barking Sands at 159.6°W and Balasore at 86.9°E). The longitude-dependent differences are found to be about 10-20 m s -1 (amounting to 50-200% in some cases) for the semi-annual oscillation (SAO) and the annual oscillation (AO) amplitudes, depending upon the altitude and latitude. Inter-annual variations of about 10 m s -1 also exist in both oscillations. The phase of the SAO exhibits an almost 180° shift at Kwajalein compared to that at the other two stations near 8.5°, while the phase of the AO is independent of longitude, in the stratosphere. The amplitude and phase of the quasi-biennial oscillation (QBO) are found to be almost independent of longitude in the 18-38 km range, but above 40 km height the QBO amplitude and phase have different values in different longitude sectors for the three stations near ±8.5° latitude. The mean zonal wind shows no change from 1979 to 1980, but in the troposphere at 8.5° latitude strong easterlies prevail in the Indian zone, in contrast to the westerlies at the Atlantic and Pacific stations.

The inter-decadal correlation between summer arctic oscillation and summer drought and moist characteristic of northwest China

Science.gov (United States)

Wang, Pengxiang; Zheng, Youfei; Sun, Landong; Ren, Zhenhe; He, Jinhai; Zhang, Qiang

2007-09-01

In the context of 1960~2003 summertime rainfall and small-sized pan evaporations from 131 stations distributed over NW China covering Xinjiang, Qinghai, Gansu, Ningxia, Shaanxi as well as western Nei Mongolia, and Arctic Oscillation Indices (AOI) we define a homogenized index for aridity or wetness feature, with which to examine the relations between AOI and NW China aridity-wetness regime, indicating their noticeable relations on an interdecadal basis. It is found that during the decade of summer Arctic oscillation stronger than mean, the sea level pressure field shows positive (negative) anomalies over Asian landmass, a stronger anticyclonic anomaly circulation appears at 700 hPa over Lake Baikal and to the south, westerly (northerly) departure emerges in the westerly (monsoon) portion of NW China, as well as over NW China there appears a structure with a low in the west and a high in the east at the 500 hPa height field, suggestive of east-Asian summer monsoon weaker than normal such that westerly flows prevail in the westerly zone of NW China, leading to rainfall more than mean for a wetter climate while in its monsoon area the northerly winds are dominant, with precipitation less than normal, resulting in a climate drier in comparison to mean and v.v. for the decade with summer AO weaker than normal.

Modeling of wind turbines for power system studies

Energy Technology Data Exchange (ETDEWEB)

Petru, T.

2001-05-01

When wind turbines are installed into the electric grid, the power quality is affected. Today, strict installation recommendations often prevail due to a lack of knowledge on this subject. Consequently, it is important to predict the impact of wind turbines on the electric grid before the turbines are installed. The thesis describes relevant power quality issues, discusses different configurations of wind turbines with respect to power quality and draw requirements regarding wind turbine modeling. A model of a stall-regulated, fixed-speed wind turbine system is introduced and its power quality impact on the electric grid is evaluated. The model is verified with field measurements.

Long-period variations of wind parameters in the mesopause region and the solar cycle dependence

International Nuclear Information System (INIS)

Greisiger, K.M.; Schminder, R.; Kuerschner, D.

1987-01-01

The solar cycle dependence of wind parameters below 100 km on the basis of long term continuous ionospheric drift measurements in the low frequency range is discussed. For the meridional prevailing wind no significant variation was found. The same comparison as for winter was done for summer where the previous investigations gave no correlation. Now the radar meteor wind measurement values, too, showed a significant negative correlation of the zonal prevailing wind with solar activity for the years 1976 to 1983. The ionospheric drift measurement results of Collm have the same tendency but a larger dispersion due to the lower accuracy of the harmonic analysis because of the shorter daily measuring interval in summer. Continuous wind observations in the upper mesopause region over more than 20 years revealed distinct long term variations, the origin of which cannot be explained with the present knowledge

Will surface winds weaken in response to global warming?

Science.gov (United States)

Ma, Jian; Foltz, Gregory R.; Soden, Brian J.; Huang, Gang; He, Jie; Dong, Changming

2016-12-01

The surface Walker and tropical tropospheric circulations have been inferred to slow down from historical observations and model projections, yet analysis of large-scale surface wind predictions is lacking. Satellite measurements of surface wind speed indicate strengthening trends averaged over the global and tropical oceans that are supported by precipitation and evaporation changes. Here we use corrected anemometer-based observations to show that the surface wind speed has not decreased in the averaged tropical oceans, despite its reduction in the region of the Walker circulation. Historical simulations and future projections for climate change also suggest a near-zero wind speed trend averaged in space, regardless of the Walker cell change. In the tropics, the sea surface temperature pattern effect acts against the large-scale circulation slow-down. For higher latitudes, the surface winds shift poleward along with the eddy-driven mid-latitude westerlies, resulting in a very small contribution to the global change in surface wind speed. Despite its importance for surface wind speed change, the influence of the SST pattern change on global-mean rainfall is insignificant since it cannot substantially alter the global energy balance. As a result, the precipitation response to global warming remains ‘muted’ relative to atmospheric moisture increase. Our results therefore show consistency between projections and observations of surface winds and precipitation.

Tidal analysis of Met rocket wind data

Science.gov (United States)

Bedinger, J. F.; Constantinides, E.

1976-01-01

A method of analyzing Met Rocket wind data is described. Modern tidal theory and specialized analytical techniques were used to resolve specific tidal modes and prevailing components in observed wind data. A representation of the wind which is continuous in both space and time was formulated. Such a representation allows direct comparison with theory, allows the derivation of other quantities such as temperature and pressure which in turn may be compared with observed values, and allows the formation of a wind model which extends over a broader range of space and time. Significant diurnal tidal modes with wavelengths of 10 and 7 km were present in the data and were resolved by the analytical technique.

Wind climatology observed over Kalpakkam using Doppler sodar

International Nuclear Information System (INIS)

Narayana Rao, D.; Krishna Reddy, K.; Vijaya Kumar, T.R.; Kishore, P.

1996-01-01

Acoustic remote sensing of the prevailing winds in the boundary layer finds an important application in studying the problems related to air pollution meteorology. Analysis of the seasonal variation of vertical and horizontal wind speed with altitude is made using the Doppler sodar data collected at an atomic research centre, Kalpakkam. A pictorial representation of horizontal wind flow for each season is given in the form of wind roses at three lower levels of probing, namely 100, 300 and 500 m. Such analysis would prove to be a basic reference material for taking necessary meaningful emergency measures in similar climatic regions. (author). 18 refs., 10 figs

Earth aeolian wind streaks: Comparison to wind data from model and stations

Science.gov (United States)

Cohen-Zada, A. L.; Maman, S.; Blumberg, D. G.

2017-05-01

Wind streak is a collective term for a variety of aeolian features that display distinctive albedo surface patterns. Wind streaks have been used to map near-surface winds and to estimate atmospheric circulation patterns on Mars and Venus. However, because wind streaks have been studied mostly on Mars and Venus, much of the knowledge regarding the mechanism and time frame of their formation and their relationship to the atmospheric circulation cannot be verified. This study aims to validate previous studies' results by a comparison of real and modeled wind data with wind streak orientations as measured from remote-sensing images. Orientations of Earth wind streaks were statistically correlated to resultant drift direction (RDD) values calculated from reanalysis and wind data from 621 weather stations. The results showed good agreement between wind streak orientations and reanalysis RDD (r = 0.78). A moderate correlation was found between the wind streak orientations and the weather station data (r = 0.47); a similar trend was revealed on a regional scale when the analysis was performed by continent, with r ranging from 0.641 in North America to 0.922 in Antarctica. At sites where wind streak orientations did not correspond to the RDDs (i.e., a difference of 45°), seasonal and diurnal variations in the wind flow were found to be responsible for deviation from the global pattern. The study thus confirms that Earth wind streaks were formed by the present wind regime and they are indeed indicative of the long-term prevailing wind direction on global and regional scales.

29 CFR 525.10 - Prevailing wage rates.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Prevailing wage rates. 525.10 Section 525.10 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS EMPLOYMENT OF WORKERS WITH DISABILITIES UNDER SPECIAL CERTIFICATES § 525.10 Prevailing wage rates. (a) A...

Federal Prevailing Rate Advisory Committee (FPRAC) Annual Reports

Data.gov (United States)

Office of Personnel Management — Annual reports of the Federal Prevailing Rate Advisory Committee (FPRAC), which studies the prevailing (market) rate system for wages and other matters pertinent to...

29 CFR 4.51 - Prevailing in the locality determinations.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Prevailing in the locality determinations. 4.51 Section 4.51... Procedures § 4.51 Prevailing in the locality determinations. (a) Information considered. The minimum monetary... benefits contained in collective bargaining agreements where they have been determined to prevail in a...

Evaluation of the Wind Flow Variability Using Scanning Doppler Lidar Measurements

Science.gov (United States)

Sand, S. C.; Pichugina, Y. L.; Brewer, A.

2016-12-01

Better understanding of the wind flow variability at the heights of the modern turbines is essential to accurately assess of generated wind power and efficient turbine operations. Nowadays the wind energy industry often utilizes scanning Doppler lidar to measure wind-speed profiles at high spatial and temporal resolution.The study presents wind flow features captured by scanning Doppler lidars during the second Wind Forecast and Improvement Project (WFIP 2) sponsored by the Department of Energy (DOE) and National Oceanic and Atmospheric Administration (NOAA). This 18-month long experiment in the Columbia River Basin aims to improve model wind forecasts complicated by mountain terrain, coastal effects, and numerous wind farms.To provide a comprehensive dataset to use for characterizing and predicting meteorological phenomena important to Wind Energy, NOAA deployed scanning, pulsed Doppler lidars to two sites in Oregon, one at Wasco, located upstream of all wind farms relative to the predominant westerly flow in the region, and one at Arlington, located in the middle of several wind farms.In this presentation we will describe lidar scanning patterns capable of providing data in conical, or vertical-slice modes. These individual scans were processed to obtain 15-min averaged profiles of wind speed and direction in real time. Visualization of these profiles as time-height cross sections allows us to analyze variability of these parameters with height, time and location, and reveal periods of rapid changes (ramp events). Examples of wind flow variability between two sites of lidar measurements along with examples of reduced wind velocity downwind of operating turbines (wakes) will be presented.

Lateglacial and Holocene climatic changes in south-eastern Patagonia inferred from carbonate isotope records of Laguna Potrok Aike (Argentina)

Science.gov (United States)

Oehlerich, M.; Mayr, C.; Gussone, N.; Hahn, A.; Hölzl, S.; Lücke, A.; Ohlendorf, C.; Rummel, S.; Teichert, B. M. A.; Zolitschka, B.

2015-04-01

First results of strontium, calcium, carbon and oxygen isotope analyses of bulk carbonates from a 106 m long sediment record of Laguna Potrok Aike, located in southern Patagonia are presented. Morphological and isotopic investigations of μm-sized carbonate crystals in the sediment reveal an endogenic origin for the entire Holocene. During this time period the calcium carbonate record of Laguna Potrok Aike turned out to be most likely ikaite-derived. As ikaite precipitation in nature has only been observed in a narrow temperature window between 0 and 7 °C, the respective carbonate oxygen isotope ratios serve as a proxy of hydrological variations rather than of palaeotemperatures. We suggest that oxygen isotope ratios are sensitive to changes of the lake water balance induced by intensity variations of the Southern Hemisphere Westerlies and discuss the role of this wind belt as a driver for climate change in southern South America. In combination with other proxy records the evolution of westerly wind intensities is reconstructed. Our data suggest that weak SHW prevailed during the Lateglacial and the early Holocene, interrupted by an interval with strengthened Westerlies between 13.4 and 11.3 ka cal BP. Wind strength increased at 9.2 ka cal BP and significantly intensified until 7.0 ka cal BP. Subsequently, the wind intensity diminished and stabilised to conditions similar to present day after a period of reduced evaporation during the "Little Ice Age". Strontium isotopes (87Sr/86Sr ratio) were identified as a potential lake-level indicator and point to a lowering from overflow conditions during the Glacial (∼17 ka cal BP) to lowest lake levels around 8 ka cal BP. Thereafter the strontium isotope curve resembles the lake-level curve which is stepwise rising until the "Little Ice Age". The variability of the Ca isotope composition of the sediment reflects changes in the Ca budget of the lake, indicating higher degrees of Ca utilisation during the period with

Modulation of frontogenetic plankton production along a meandering jet by zonal wind forcing: An application to the Alboran Sea

Science.gov (United States)

Oguz, Temel; Mourre, Baptiste; Tintoré, Joaquin

2017-08-01

We present a coupled physical-biological modeling study to elucidate the changes in ageostrophic frontal dynamics and the frontogenetic plankton production characteristics of a meandering jet under the impacts of successive westerly/easterly wind events combined with seasonal variations in the upstream transport and buoyancy flux characteristics of the jet, using a case study for the Alboran Sea (Western Mediterranean). Their nonlinear coupling is shown to result in different forms of physical and biological characteristics of the background jet structure that follows a meandering path around two anticyclonic gyres in the western and eastern basins and a cyclonic eddy in between. The westerly, downfront wind events broaden the jet, and result in stronger cross-frontal density contrast and intensify ageostrophic cross-frontal secondary circulation. Thus, they improve the frontogenetic plankton production with respect to the no-wind case. They also support higher production along the northern coast in response to wind-induced coastal upwelling and spreading of resulting nutrient-rich, productive water by mesoscale stirring. These features weaken gradually as the jet transport reduces. In contrast, stronger and longer-lasting easterlies during the reduced jet transport phase weaken the currents and frontal density structure, change the circular Western Alboran Gyre to an elongated form, and shift the main axis of the jet towards the southern basin. Then, frontogenesis fails to contribute to phytoplankton production that becomes limited to the eddy pumping within cyclones. Apart from the frontogenetic production, eddy pumping, mesoscale stirring, and diapycnal mixing of nutrients support intermittent and localized phytoplankton patches over the basin.

Impact of East Asian Winter and Australian Summer Monsoons on the Enhanced Surface Westerlies over the Western Tropical Pacific Ocean Preceding the El Niño Onset

Science.gov (United States)

Zheng, Y.; Zhang, R.; Bourassa, M. A.

2014-12-01

Composite analysis from NCEP-NCAR reanalysis datasets over the period 1948-2007 indicates that stronger East Asian winter monsoons (EAWM) and stronger Australian summer monsoons (ASM) generally co-exist in boreal winters preceding the onset of El Niño, although the EAWM tend to be weak after 1990, probably because of the decadal shift of EAWM and the change in El Niño events from cold-tongue type to warm-pool type. The anomalous EAWM and ASM enhance surface westerlies over the western tropical Pacific Ocean (WTP). It is proposed that the enhanced surface westerlies over the WTP prior to El Niño onset are generally associated with the concurrent anomalous EAWM and ASM. A simple analytical atmospheric model is constructed to test the hypothesis that the emergence of enhanced surface westerlies over the WTP can be linked to concurrent EAWM and ASM anomalies. Model results indicate that when anomalous northerlies from the EAWM converge with anomalous southerlies from the ASM, westerly anomalies over the WTP are enhanced. This result provides a possible explanation of the co-impact of the EAWM and the ASM on the onset of El Niño through enhancing the surface westerly over the WTP.

Influence of local wind speed and direction on wind power dynamics – Application to offshore very short-term forecasting

DEFF Research Database (Denmark)

Gallego, Cristobal; Pinson, Pierre; Madsen, Henrik

2011-01-01

Wind power time series usually show complex dynamics mainly due to non-linearities related to the wind physics and the power transformation process in wind farms. This article provides an approach to the incorporation of observed local variables (wind speed and direction) to model some of these e......Wind power time series usually show complex dynamics mainly due to non-linearities related to the wind physics and the power transformation process in wind farms. This article provides an approach to the incorporation of observed local variables (wind speed and direction) to model some...... on one-step ahead forecasting and a time series resolution of 10 min. It has been found that the local wind direction contributes to model some features of the prevailing winds, such as the impact of the wind direction on the wind variability, whereas the non-linearities related to the power...... transformation process can be introduced by considering the local wind speed. In both cases, conditional parametric models showed a better performance than the one achieved by the regime-switching strategy. The results attained reinforce the idea that each explanatory variable allows the modelling of different...

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

Directory of Open Access Journals (Sweden)

Bo Hong

2018-01-01

Full Text Available Airflow behavior and indoor/outdoor PM2.5 dispersion in different building–tree grouping patterns depend significantly on the building–tree layouts and orientation towards the prevailing wind. By using a standard k-ε model and a revised generalized drift flux model, this study evaluated airflow fields and indoor/outdoor relationships for PM2.5 resulting from partly wind-induced natural ventilation in four hypothetical building–tree grouping patterns. Results showed that: (1 Patterns provide a variety of natural ventilation potential that relies on the wind influence, and buildings that deflect wind on the windward facade and separate airflow on the leeward facade have better ventilation potential; (2 Patterns where buildings and trees form a central space and a windward opening side towards the prevailing wind offer the best ventilation conditions; (3 Under the assumption that transported pollution sources are diluted through the inlet, the aerodynamics and deposition effects of trees cause the lower floors of a multi-storey building to be exposed to lower PM2.5 compared with upper floors, and lower indoor PM2.5 values were found close to the tree canopy; (4 Wind pressure differences across each flat showed a poor correlation (R2 = 0.059, with indoor PM2.5 concentrations; and (5 Patterns with the long facade of buildings and trees perpendicular to the prevailing wind have the lowest indoor PM2.5 concentrations.

A joint probability density function of wind speed and direction for wind energy analysis

International Nuclear Information System (INIS)

Carta, Jose A.; Ramirez, Penelope; Bueno, Celia

2008-01-01

A very flexible joint probability density function of wind speed and direction is presented in this paper for use in wind energy analysis. A method that enables angular-linear distributions to be obtained with specified marginal distributions has been used for this purpose. For the marginal distribution of wind speed we use a singly truncated from below Normal-Weibull mixture distribution. The marginal distribution of wind direction comprises a finite mixture of von Mises distributions. The proposed model is applied in this paper to wind direction and wind speed hourly data recorded at several weather stations located in the Canary Islands (Spain). The suitability of the distributions is judged from the coefficient of determination R 2 . The conclusions reached are that the joint distribution proposed in this paper: (a) can represent unimodal, bimodal and bitangential wind speed frequency distributions, (b) takes into account the frequency of null winds, (c) represents the wind direction regimes in zones with several modes or prevailing wind directions, (d) takes into account the correlation between wind speeds and its directions. It can therefore be used in several tasks involved in the evaluation process of the wind resources available at a potential site. We also conclude that, in the case of the Canary Islands, the proposed model provides better fits in all the cases analysed than those obtained with the models used in the specialised literature on wind energy

Dynamics of cyanobacterial bloom formation during short-term hydrodynamic fluctuation in a large shallow, eutrophic, and wind-exposed Lake Taihu, China.

Science.gov (United States)

Wu, Tingfeng; Qin, Boqiang; Zhu, Guangwei; Luo, Liancong; Ding, Yanqing; Bian, Geya

2013-12-01

Short-term hydrodynamic fluctuations caused by extreme weather events are expected to increase worldwide because of global climate change, and such fluctuations can strongly influence cyanobacterial blooms. In this study, the cyanobacterial bloom disappearance and reappearance in Lake Taihu, China, in response to short-term hydrodynamic fluctuations, was investigated by field sampling, long-term ecological records, high-frequency sensors and MODIS satellite images. The horizontal drift caused by the dominant easterly wind during the phytoplankton growth season was mainly responsible for cyanobacterial biomass accumulation in the western and northern regions of the lake and subsequent bloom formation over relatively long time scales. The cyanobacterial bloom changed slowly under calm or gentle wind conditions. In contrast, the short-term bloom events within a day were mainly caused by entrainment and disentrainment of cyanobacterial colonies by wind-induced hydrodynamics. Observation of a westerly event in Lake Taihu revealed that when the 30 min mean wind speed (flow speed) exceeded the threshold value of 6 m/s (5.7 cm/s), cyanobacteria in colonies were entrained by the wind-induced hydrodynamics. Subsequently, the vertical migration of cyanobacterial colonies was controlled by hydrodynamics, resulting in thorough mixing of algal biomass throughout the water depth and the eventual disappearance of surface blooms. Moreover, the intense mixing can also increase the chance for forming larger and more cyanobacterial colonies, namely, aggregation. Subsequently, when the hydrodynamics became weak, the cyanobacterial colonies continuously float upward without effective buoyancy regulation, and cause cyanobacterial bloom explosive expansion after the westerly. Furthermore, the results of this study indicate that the strong wind happening frequently during April and October can be an important cause of the formation and expansion of cyanobacterial blooms in Lake Taihu.

Long-term trends in near-surface flow over the Baltic

DEFF Research Database (Denmark)

Pryor, S.C.; Barthelmie, R.J.

2003-01-01

in wind speed are strongly linked to changes in the synoptic-scale circulation. The majority of the increase in wintertime wind speeds is attributable to an increase in westerly anticyclonic, westerly cyclonic and northwesterly cyclonic circulation types as manifest in the Grosswetterlagen catalogue...

Speciation of organic aerosols in the Saharan Air Layer and in the free troposphere westerlies

Directory of Open Access Journals (Sweden)

M. I. García

2017-07-01

Full Text Available We focused this research on the composition of the organic aerosols transported in the two main airflows of the subtropical North Atlantic free troposphere: (i the Saharan Air Layer – the warm, dry and dusty airstream that expands from North Africa to the Americas at subtropical and tropical latitudes – and (ii the westerlies, which flow from North America over the North Atlantic at mid- and subtropical latitudes. We determined the inorganic compounds (secondary inorganic species and elemental composition, elemental carbon and the organic fraction (bulk organic carbon and organic speciation present in the aerosol collected at Izaña Observatory,  ∼  2400 m a.s.l. on the island of Tenerife. The concentrations of all inorganic and almost all organic compounds were higher in the Saharan Air Layer than in the westerlies, with bulk organic matter concentrations within the range 0.02–4.0 µg m−3. In the Saharan Air Layer, the total aerosol population was by far dominated by dust (93 % of bulk mass, which was mixed with secondary inorganic pollutants ( <  5 % and organic matter ( ∼  1.5 %. The chemical speciation of the organic aerosols (levoglucosan, dicarboxylic acids, saccharides, n-alkanes, hopanes, polycyclic aromatic hydrocarbons and those formed after oxidation of α-pinene and isoprene, determined by gas chromatography coupled with mass spectrometry accounted for 15 % of the bulk organic matter (determined by the thermo-optical transmission technique; the most abundant organic compounds were saccharides (associated with surface soils, secondary organic aerosols linked to oxidation of biogenic isoprene (SOA ISO and dicarboxylic acids (linked to several primary sources and SOA. When the Saharan Air Layer shifted southward, Izaña was within the westerlies stream and organic matter accounted for  ∼  28 % of the bulk mass of aerosols. In the westerlies, the organic aerosol species determined

The dynamics of İzmir Bay under the effects of wind and thermohaline forces

Science.gov (United States)

Sayın, Erdem; Eronat, Canan

2018-04-01

The dominant circulation pattern of İzmir Bay on the Aegean Sea coast of Turkey is studied taking into consideration the influence of wind and thermohaline forces. İzmir Bay is discussed by subdividing the bay into outer, middle and inner areas. Wind is the most important driving force in the İzmir coastal area. There are also thermohaline forces due to the existence of water types of different physical properties in the bay. In contrast to the two-layer stratification during summer, a homogeneous water column exists in winter. The free surface version of the Princeton model (Killworth's 3-D general circulation model) is applied, with the input data obtained through the measurements made by the research vessel K. Piri Reis. As a result of the simulations with artificial wind, the strong consistent wind generates circulation patterns independent of the seasonal stratification in the bay. Wind-driven circulation causes cyclonic or anticyclonic movements in the middle bay where the distinct İzmir Bay Water (IBW) forms. Cyclonic movement takes place under the influence of southerly and westerly winds. On the other hand, northerly and easterly winds cause an anticyclonic movement in the middle bay. The outer and inner bay also have the wind-driven recirculation patterns expected.

Effect of land uses and wind direction on the contribution of local sources to airborne pollen.

Science.gov (United States)

Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

2015-12-15

The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae-Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen transport

Observational study of surface wind along a sloping surface over mountainous terrain during winter

Science.gov (United States)

Lee, Young-Hee; Lee, Gyuwon; Joo, Sangwon; Ahn, Kwang-Deuk

2018-03-01

The 2018 Winter Olympic and Paralympic Games will be held in Pyeongchang, Korea, during February and March. We examined the near surface winds and wind gusts along the sloping surface at two outdoor venues in Pyeongchang during February and March using surface wind data. The outdoor venues are located in a complex, mountainous terrain, and hence the near-surface winds form intricate patterns due to the interplay between large-scale and locally forced winds. During February and March, the dominant wind at the ridge level is westerly; however, a significant wind direction change is observed along the sloping surface at the venues. The winds on the sloping surface are also influenced by thermal forcing, showing increased upslope flow during daytime. When neutral air flows over the hill, the windward and leeward flows show a significantly different behavior. A higher correlation of the wind speed between upper- and lower-level stations is shown in the windward region compared with the leeward region. The strong synoptic wind, small width of the ridge, and steep leeward ridge slope angle provide favorable conditions for flow separation at the leeward foot of the ridge. The gust factor increases with decreasing surface elevation and is larger during daytime than nighttime. A significantly large gust factor is also observed in the leeward region.

Distinct wind convergence patterns in the Mexico City basin due to the interaction of the gap winds with the synoptic flow

Directory of Open Access Journals (Sweden)

B. de Foy

2006-01-01

Full Text Available Mexico City lies in a high altitude basin where air quality and pollutant fate is strongly influenced by local winds. The combination of high terrain with weak synoptic forcing leads to weak and variable winds with complex circulation patterns. A gap wind entering the basin in the afternoon leads to very different wind convergence lines over the city depending on the meteorological conditions. Surface and upper-air meteorological observations are analysed during the MCMA-2003 field campaign to establish the meteorological conditions and obtain an index of the strength and timing of the gap wind. A mesoscale meteorological model (MM5 is used in combination with high-resolution satellite data for the land surface parameters and soil moisture maps derived from diurnal ground temperature range. A simple method to map the lines of wind convergence both in the basin and on the regional scale is used to show the different convergence patterns according to episode types. The gap wind is found to occur on most days of the campaign and is the result of a temperature gradient across the southern basin rim which is very similar from day to day. Momentum mixing from winds aloft into the surface layer is much more variable and can determine both the strength of the flow and the pattern of the convergence zones. Northerly flows aloft lead to a weak jet with an east-west convergence line that progresses northwards in the late afternoon and early evening. Westerlies aloft lead to both stronger gap flows due to channelling and winds over the southern and western basin rim. This results in a north-south convergence line through the middle of the basin starting in the early afternoon. Improved understanding of basin meteorology will lead to better air quality forecasts for the city and better understanding of the chemical regimes in the urban atmosphere.

Distinct wind convergence patterns in the Mexico City basin due to the interaction of the gap winds with the synoptic flow

Science.gov (United States)

de Foy, B.; Clappier, A.; Molina, L. T.; Molina, M. J.

2006-04-01

Mexico City lies in a high altitude basin where air quality and pollutant fate is strongly influenced by local winds. The combination of high terrain with weak synoptic forcing leads to weak and variable winds with complex circulation patterns. A gap wind entering the basin in the afternoon leads to very different wind convergence lines over the city depending on the meteorological conditions. Surface and upper-air meteorological observations are analysed during the MCMA-2003 field campaign to establish the meteorological conditions and obtain an index of the strength and timing of the gap wind. A mesoscale meteorological model (MM5) is used in combination with high-resolution satellite data for the land surface parameters and soil moisture maps derived from diurnal ground temperature range. A simple method to map the lines of wind convergence both in the basin and on the regional scale is used to show the different convergence patterns according to episode types. The gap wind is found to occur on most days of the campaign and is the result of a temperature gradient across the southern basin rim which is very similar from day to day. Momentum mixing from winds aloft into the surface layer is much more variable and can determine both the strength of the flow and the pattern of the convergence zones. Northerly flows aloft lead to a weak jet with an east-west convergence line that progresses northwards in the late afternoon and early evening. Westerlies aloft lead to both stronger gap flows due to channelling and winds over the southern and western basin rim. This results in a north-south convergence line through the middle of the basin starting in the early afternoon. Improved understanding of basin meteorology will lead to better air quality forecasts for the city and better understanding of the chemical regimes in the urban atmosphere.

Wind profiler observations of a monsoon low-level jet over a tropical Indian station

Directory of Open Access Journals (Sweden)

M. C. R. Kalapureddy

2007-11-01

Full Text Available Three-year high-resolution wind observations of the wind profiler have been utilized to characterize the diurnal and seasonal features of the monsoon Low-Level Jet (LLJ over a tropical station, Gadanki (13.5° N, 79.2° E, with a focus on the diurnal variability of low-level winds. The Boreal summer monsoon winds show a conspicuously strong westerly LLJ with average wind speed exceeding 20 m s⁻¹. The L-band wind profiler measurements have shown an advantage of better height and time resolutions over the conventional radiosonde method for diurnal wind measurements. An interesting diurnal oscillation of LLJ core has been observed. It is varying in the height range of 1.8±0.6 km with the maximum and minimum intensity noticed during the early morning and afternoon hours, respectively. The jet core (wind maxima height is observed to coincide with the inversion height. Strong wind shears are normally located beneath the LLJ core. The sole wind profiler observations are capable of identifying the monsoon phases, such as onset, break and active spells, etc. The mutual influence between the LLJ and the boundary layer has been discussed. One notices that the observed LLJ diurnal structures depend on the local convective activity, wind shears and turbulence activity associated with boundary layer winds. The day-to-day change in the LLJ structure depends on the latitudinal position of the LLJ core.

Shorlist Masterplan Wind. Evaluation of the sampling grid of the year-round ichthyoplankton survey

NARCIS (Netherlands)

Bolle, L.J.; Beek, van J.K.L.

2011-01-01

Within the research programme 'Shortlist Masterplan Wind' a year-round ichthyoplankton survey is being carried out. The sampling area is based on known spawning concentrations and prevailing currents.

The PREVAIL Study

DEFF Research Database (Denmark)

Evans, Christopher P; Higano, Celestia S; Keane, Thomas

2016-01-01

BACKGROUND: Enzalutamide, an oral androgen receptor inhibitor, significantly improved overall survival (OS) and radiographic progression-free survival (rPFS) versus placebo in the PREVAIL trial of men with chemotherapy-naïve metastatic castration-resistant prostate cancer. OBJECTIVE: To assess...... in men with chemotherapy-naïve metastatic castration-resistant prostate cancer, with or without visceral disease, low- or high-volume bone disease, or lymph node only disease. PATIENT SUMMARY: Patients with metastatic castration-resistant prostate cancer-including those with or without visceral disease...

Lattice Wind Description and Characterization of Mexico City Local Wind Events in the 2001–2006 Period

Directory of Open Access Journals (Sweden)

Alejandro Salcido

2015-07-01

Full Text Available Urban transformation and expansion in Mexico City continuously affect its urban morphology, and therefore the modes of wind circulation inside it and their occurrence probabilities. Knowledge on these topics is an important issue for urban planning and for other urban studies, such as air quality assessment. In this paper, using a lattice wind model at a meso-β scale, we develop a simple description and characterization of Mexico City local wind events that occurred during the period 2001–2006, including an estimation of the occurrence probabilities. This region was modeled as a 2D lattice domain of identical cells, and wind conditions in each cell were described by four wind attributes: the horizontal velocity components, divergence, and vorticity. Models of one and four cells were applied to wind data furnished by the meteorological network of the city. Results include the following: Early morning: low intensity winds (75% from N, NW, W and SW (75%, convergent (93%, with a slight predominance of cyclonic vorticity (54%. Morning and early afternoon: winds from N, NE and E (72% with speeds from 0.5 to 3.5 m/s, slight prevailing of convergent winds (51%, and slight predominance of cyclonic vorticity (57%. Late afternoon and night: winds blowing from N, NW, and S (63% with speeds from 1.5 to 3.5 m/s (66%, convergent (90%, and cyclonic (72%.

Comparison of slant-path scintillometry, sonic anemometry and high-speed videography for vertical profiling of turbulence in the atmospheric surface layer

CSIR Research Space (South Africa)

Griffith, DJ

2013-09-01

Full Text Available -zero temperatures were encountered after 00:00 UTC on occasion with formation of some fog, dew or frost. Winds were predominantly from the southerly direction at night and north-westerly direction during the day. The wind changeover times were about 07:00 UTC and 17...:00 UTC. The wind statistics and wind run over the period 23 to 29 June, 2013 are given in Figure 6. The wind run has a characteristic diurnal sawtooth shape, but strongly dominated by the day-period westerly component. Mean night-period (17:00 to 07...

48 CFR 22.1002-2 - Wage determinations based on prevailing rates.

Science.gov (United States)

2010-10-01

... on prevailing rates. 22.1002-2 Section 22.1002-2 Federal Acquisition Regulations System FEDERAL... Contract Act of 1965, as Amended 22.1002-2 Wage determinations based on prevailing rates. Contractors... Department of Labor to prevail in the locality or, in the absence of a wage determination, the minimum wage...

Some atmospheric dispersion, wind and temperature statistics from Jervis Bay, Australian Capital Territory 1972 to 1974

International Nuclear Information System (INIS)

Clark, G.H.

1985-07-01

A meteorological study of winds, temperatures and Pasquill stability categories was conducted in the coastal conditions at Jervis Bay. Three Pasquill stability categorisation schemes were compared. These indicated a predominance of neutral to slightly unstable conditions. During the daytime, north bay breezes and north-east sea breezes were most common together with on-shore south-east winds. Off-shore south-west winds prevailed during winter and were observed most frequently at night

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2010-06-16

... OFFICE OF PERSONNEL MANAGEMENT Federal Prevailing Rate Advisory Committee; Cancellation of... Prevailing Rate Advisory Committee is issuing this notice to cancel the June 17, 2010, public [email protected] ; or FAX: (202) 606-4264. Sheldon Friedman, Chairman, Federal Prevailing Rate...

Economic feasibility analysis of a wind farm in Caldas da Rainha, Portugal

Energy Technology Data Exchange (ETDEWEB)

de Oliveira, Wagner Sousa; Fernandes, Antonio Jorge [Department of Economics, Management and Industrial Engineering, University of Aveiro & Campus Universitario de Santiago, 3810-193 Aveiro (Portugal)

2012-07-01

This paper presents the technical and economical feasibility of a wind farm. The method is applied to a potential wind farm site located in Caldas da Rainha, Portugal. The site is considered on technical and economical parameters for the complete plant and its running costs. For technical consideration wind speed, prevailing wind direction, and temperature measurements are performed by using RETScreen Climate Database and Retscreen Product Database. The economic and financial evaluation of the wind farm is made by the software RETScreen(reg. sign) International Clean Energy Project Analysis and the indicators calculated are WACC, NPV, IRR, SPB, DPB, TLCC, BCR, LCOE, RR and UPAC. The sensitivity analysis backs up the findings through the scenarios developed (Current, S1, S2 and S3).

Pilot project wind power - Large scale wind power in northern Sweden; Pilotprojekt vindkraft - Storskalig vindkraft i norra Sverige

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

The Swedish Energy Agency granted 2009-04-20 Svevind AB financial aid to implement {sup P}ilot project wind power- Large scale wind power in northern Sweden{sup .} The purpose of the aid is to implement pilot sub-projects in wind power, to to increase knowledge for the larger establishments. The Energy Agency said in its decision that the projects Dragaliden and Gabriel Mountain is of 'great importance for future large-scale development of wind power in Sweden'. The special conditions prevailing in the project, forest environment and cold climate, gives the possibility of studies of wind turbines on birds, reindeer herding and hunting and the more technical aspects, such as de-icing and obstacle lighting. The objectives of the project, in addition to the construction and operation of 32 wind turbines, has been to include evaluating the permit process, studying the social effects around the wind power, to study the impact on small game hunting, perform tests of the de-icing system, investigate impacts on reindeer herding and explain the outcome of the project-generated rural funds. Some of the above sub-projects have been completed, which are reported in this report. For the sub-projects still in progress, the report presents the results to date, until the completion.

Prevailing Torque Locking Feature in Threaded Fasteners Using Anaerobic Adhesive

Science.gov (United States)

Hernandez, Alan; Hess, Daniel P.

2016-01-01

This paper presents results from tests to assess the use of anaerobic adhesive for providing a prevailing torque locking feature in threaded fasteners. Test procedures are developed and tests are performed on three fastener materials, four anaerobic adhesives, and both unseated assembly conditions. Five to ten samples are tested for each combination. Tests for initial use, reuse without additional adhesive, and reuse with additional adhesive are performed for all samples. A 48-hour cure time was used for all initial use and reuse tests. Test data are presented as removal torque versus removal angle with the specification required prevailing torque range added for performance assessment. Percent specification pass rates for the all combinations of fastener material, adhesive, and assembly condition are tabulated and reveal use of anaerobic adhesive as a prevailing torque locking feature is viable. Although not every possible fastener material and anaerobic adhesive combination provides prevailing torque values within specification, any combination can be assessed using the test procedures presented. Reuse without additional anaerobic adhesive generally provides some prevailing torque, and in some cases within specification. Reuse with additional adhesive often provides comparable removal torque data as in initial use.

76 FR 12769 - Federal Prevailing Rate Advisory Committee; Cancellation of Upcoming Meeting

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2011-03-08

... OFFICE OF PERSONNEL MANAGEMENT Federal Prevailing Rate Advisory Committee; Cancellation of... Prevailing Rate Advisory Committee is issuing this notice to cancel the March 17, 2011, public meeting..., Chairman, Federal Prevailing Rate Advisory Committee. [FR Doc. 2011-5266 Filed 3-7-11; 8:45 am] BILLING...

78 FR 20359 - Federal Prevailing Rate Advisory Committee; Cancellation of Upcoming Meeting

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2013-04-04

... OFFICE OF PERSONNEL MANAGEMENT Federal Prevailing Rate Advisory Committee; Cancellation of... Prevailing Rate Advisory Committee is issuing this notice to cancel the April 18, 2013, public meeting... Officer, Federal Prevailing Rate Advisory Committee. [FR Doc. 2013-07875 Filed 4-3-13; 8:45 am] BILLING...

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2011-11-14

... OFFICE OF PERSONNEL MANAGEMENT Federal Prevailing Rate Advisory Committee; Cancellation of... Prevailing Rate Advisory Committee is issuing this notice to cancel the November 17, 2011, public meeting..., Chairman, Federal Prevailing Rate Advisory Committee. [FR Doc. 2011-29274 Filed 11-10-11; 8:45 am] BILLING...

Effect of land uses and wind direction on the contribution of local sources to airborne pollen

International Nuclear Information System (INIS)

Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

2015-01-01

The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20 km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae–Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen transport

Effect of land uses and wind direction on the contribution of local sources to airborne pollen

Energy Technology Data Exchange (ETDEWEB)

Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

2015-12-15

The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20 km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae–Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen

78 FR 41962 - Federal Prevailing Rate Advisory Committee; Cancellation of Upcoming Meeting

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2013-07-12

... OFFICE OF PERSONNEL MANAGEMENT Federal Prevailing Rate Advisory Committee; Cancellation of... Prevailing Rate Advisory Committee is issuing this notice to cancel the July 18, 2013, public meeting... Prevailing Rate Advisory Committee. [FR Doc. 2013-16763 Filed 7-11-13; 8:45 am] BILLING CODE 6325-49-P ...

77 FR 28640 - Federal Prevailing Rate Advisory Committee; Cancellation of Upcoming Meeting

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2012-05-15

... OFFICE OF PERSONNEL MANAGEMENT Federal Prevailing Rate Advisory Committee; Cancellation of... Prevailing Rate Advisory Committee is issuing this notice to cancel the May 24, 2012, public meeting..., Federal Prevailing Rate Advisory Committee. [FR Doc. 2012-11728 Filed 5-14-12; 8:45 am] BILLING CODE 6325...

Production of electricity from the wind: a preliminary feasibility study for Greece

Energy Technology Data Exchange (ETDEWEB)

Galanis, N

1977-01-01

Wind statistics for Greece show that the conditions prevailing on the Aegean islands--i.e. considerable amounts of wind energy, small electrical loads and high generation costs--are especially favorable for the installation of wind turbine generators (WTGs). This study gives preliminary design parameters for WTGs at six locations and evaluates their performance. The duration of operation varies from 5000 to 7400 hours annually and the specific production is between 2300 and 3600 kwh/kw. The installation of the WTGs would result in diesel fuel savings corresponding to a month's consumption. Finally, the cost of wind generated electricity will be lower than that from diesel engines one to three years after the installation of the WTGs.

Wind load effects on high rise buildings in Peninsular Malaysia

Science.gov (United States)

Nizamani, Z.; Thang, K. C.; Haider, B.; Shariff, M.

2018-04-01

Wind is a randomly varying dynamic phenomenon composed of a multitude of eddies of varying sizes and rotational characteristics along a general stream of air moving relative to the ground. These eddies give wind its gustiness, creating fluctuation and results in a complex flow characteristics. The wind vector at any point can be regarded as the sum of mean wind vector and the fluctuation components. These components not only vary with height but also dependant on the approach terrain and topography. Prevailing wind exerts pressure onto the structural surfaces. The effects of wind pressure in the form of shear and bending moments are found to be a major problem in structural failure. This study aims to study the effects of wind load on a fifteen-storey high rise building using EN 1991-1-4 code and MS1553:2002. The simulation results showed that by increasing the wind speed, the storey resultant forces, namely storey shear and storey moment increases significantly. Furthermore, simulation results according to EN 1991-1-4 yield higher values compared to the simulation results according to MS1553:2002.

Glacier History of the Northern Antarctic Peninsula Region Since the End of the Last Ice Age and Implications for Southern Hemisphere Westerly-Climate Changes

Science.gov (United States)

Kaplan, M. R.; Schaefer, J. M.; Strelin, J. A.; Peltier, C.; Southon, J. R.; Lepper, K. E.; Winckler, G.

2017-12-01

For the area around James Ross Island, we present new cosmogenic 10Be exposure ages on glacial deposits, and 14C ages on associated fossil materials. These data allow us to reconstruct in detail when and how the Antarctic Peninsula Ice Sheet retreated around the Island as the last Ice Age ended, and afterward when local land-based glaciers fluctuated. Similar to other studies, we found widespread deglaciation during the earliest Holocene, with fjords and bays becoming ice free between about 11,000 and 8,000 years ago. After 7,000 years ago, neoglacial type advances initiated. Then, both expansions and ice free periods occurred from the middle to late Holocene. We compare the new glacier record to those in southern Patagonia, which is on the other side of the Drake Passage, and published Southern Ocean marine records, in order to infer past middle to high latitude changes in the Southern Hemisphere Westerlies. Widespread warmth in the earliest Holocene, to the north and south of the Drake Passage, led to small glacier systems in Patagonia and wide-ranging glacier recession around the northern Antarctic Peninsula. We infer that this early Holocene period of overall glacier recession - from Patagonia to the northern Peninsula - was caused by a persistent far-southerly setting of the westerlies and accompanying warm climates. Subsequently, during the middle Holocene renewed glacier expansions occurred on both sides of the Drake Passage, which reflects that the Westerlies and associated colder climate systems were generally more equatorward. From the middle to late Holocene, glacier expansions and ice free periods (and likely related ice shelf behavior) document how the Westerlies and associated higher-latitude climate systems varied.

PREVAIL: IBM's e-beam technology for next generation lithography

Science.gov (United States)

Pfeiffer, Hans C.

2000-07-01

PREVAIL - Projection Reduction Exposure with Variable Axis Immersion Lenses represents the high throughput e-beam projection approach to NGL which IBM is pursuing in cooperation with Nikon Corporation as alliance partner. This paper discusses the challenges and accomplishments of the PREVAIL project. The supreme challenge facing all e-beam lithography approaches has been and still is throughput. Since the throughput of e-beam projection systems is severely limited by the available optical field size, the key to success is the ability to overcome this limitation. The PREVAIL technique overcomes field-limiting off-axis aberrations through the use of variable axis lenses, which electronically shift the optical axis simultaneously with the deflected beam so that the beam effectively remains on axis. The resist images obtained with the Proof-of-Concept (POC) system demonstrate that PREVAIL effectively eliminates off- axis aberrations affecting both resolution and placement accuracy of pixels. As part of the POC system a high emittance gun has been developed to provide uniform illumination of the patterned subfield and to fill the large numerical aperture projection optics designed to significantly reduce beam blur caused by Coulomb interaction.

Climatological lower thermosphere winds as seen by ground-based and space-based instruments

Directory of Open Access Journals (Sweden)

J. M. Forbes

2004-06-01

Full Text Available Comparisons are made between climatological dynamic fields obtained from ground-based (GB and space-based (SB instruments with a view towards identifying SB/GB intercalibration issues for TIMED and other future aeronomy satellite missions. SB measurements are made from the High Resolution Doppler Imager (HRDI instrument on the Upper Atmosphere Research Satellite (UARS. The GB data originate from meteor radars at Obninsk, (55° N, 37° E, Shigaraki (35° N, 136° E and Jakarta (6° S, 107° E and MF spaced-antenna radars at Hawaii (22° N, 160° W, Christmas I. (2° N, 158° W and Adelaide (35° S, 138° E. We focus on monthly-mean prevailing, diurnal and semidiurnal wind components at 96km, averaged over the 1991-1999 period. We perform space-based (SB analyses for 90° longitude sectors including the GB sites, as well as for the zonal mean. Taking the monthly prevailing zonal winds from these stations as a whole, on average, SB zonal winds exceed GB determinations by ~63%, whereas meridional winds are in much better agreement. The origin of this discrepancy remains unknown, and should receive high priority in initial GB/SB comparisons during the TIMED mission. We perform detailed comparisons between monthly climatologies from Jakarta and the geographically conjugate sites of Shigaraki and Adelaide, including some analyses of interannual variations. SB prevailing, diurnal and semidiurnal tides exceed those measured over Jakarta by factors, on the average, of the order of 2.0, 1.6, 1.3, respectively, for the eastward wind, although much variability exists. For the meridional component, SB/GB ratios for the diurnal and semidiurnal tide are about 1.6 and 1.7. Prevailing and tidal amplitudes at Adelaide are significantly lower than SB values, whereas similar net differences do not occur at the conjugate Northern Hemisphere location of Shigaraki. Adelaide diurnal phases lag SB phases by several hours, but excellent agreement between the two data

The role of wind field induced flow velocities in destratification and hypoxia reduction at Meiling Bay of large shallow Lake Taihu, China.

Science.gov (United States)

Jalil, Abdul; Li, Yiping; Du, Wei; Wang, Wencai; Wang, Jianwei; Gao, Xiaomeng; Khan, Hafiz Osama Sarwar; Pan, Baozhu; Acharya, Kumud

2018-01-01

Wind induced flow velocity patterns and associated thermal destratification can drive to hypoxia reduction in large shallow lakes. The effects of wind induced hydrodynamic changes on destratification and hypoxia reduction were investigated at the Meiling bay (N 31° 22' 56.4″, E 120° 9' 38.3″) of Lake Taihu, China. Vertical flow velocity profile analysis showed surface flow velocities consistency with the wind field and lower flow velocity profiles were also consistent (but with delay response time) when the wind speed was higher than 6.2 m/s. Wind field and temperature found the control parameters for hypoxia reduction and for water quality conditions at the surface and bottom profiles of lake. The critical temperature for hypoxia reduction at the surface and the bottom profile was ≤24.1C° (below which hypoxic conditions were found reduced). Strong prevailing wind field (onshore wind directions ESE, SE, SSE and E, wind speed ranges of 2.4-9.1 m/s) reduced the temperature (22C° to 24.1C°) caused reduction of hypoxia at the near surface with a rise in water levels whereas, low to medium prevailing wind field did not supported destratification which increased temperature resulting in increased hypoxia. Non-prevailing wind directions (offshore) were not found supportive for the reduction of hypoxia in study area due to less variable wind field. Daytime wind field found more variable (as compared to night time) which increased the thermal destratification during daytime and found supportive for destratification and hypoxia reduction. The second order exponential correlation found between surface temperature and Chlorophyll-a (R 2 : 0.2858, Adjusted R-square: 0.2144 RMSE: 4.395), Dissolved Oxygen (R 2 : 0.596, Adjusted R-square: 0.5942, RMSE: 0.3042) concentrations. The findings of the present study reveal the driving mechanism of wind induced thermal destratification and hypoxic conditions, which may further help to evaluate the wind role in eutrophication

29 CFR 2704.202 - Contents of application-where the applicant has prevailed.

Science.gov (United States)

2010-07-01

... 29 Labor 9 2010-07-01 2010-07-01 false Contents of application-where the applicant has prevailed... Information Required From Applicants § 2704.202 Contents of application—where the applicant has prevailed. (a) An application for an award under § 2704.105(a) shall show that the applicant has prevailed in a...

Air flow distribution in and around a single-sided naturally ventilated room

Energy Technology Data Exchange (ETDEWEB)

Eftekhari, M.M.; Marjanovic, L.D.; Pinnock, D.J. [Loughborough University (United Kingdom). Dept. of Civil and Building Engineering

2002-03-01

The objective of this research is to compare calculated and measured air flow distributions inside a test room which is naturally ventilated. The test room is situated in a relatively sheltered location and to visualise the resultant local wind pattern around the room for all prevailing wind directions, wind tunnel trials were carried out. Both the wind tunnel and full-scale measurements show that the wind direction at the test cell was generally restricted to either a westerly or an easterly direction. To investigate air flow inside the room, the air pressures and velocities across the openings together with indoor air temperature and velocity at four locations and six different levels are measured. The experimental results demonstrate that for both winter and summer the air was entering the test room at bottom and leaving at the top louvre. Separate air flow and thermal modelling programs are used to predict the spatial distribution of the air flow and thermal comfort. The air flow distribution was predicted using a network air flow program. The predicted flow showed similar trends and the simulation results were in agreement with the measured data. An explicit finite-difference thermal modeling simulation package was used to predict the thermal comfort indices.(author)

Natural wind variability triggered drop in German redispatch volume and costs from 2015 to 2016

Science.gov (United States)

Reyers, Mark; Märker, Carolin; Witthaut, Dirk

2018-01-01

Avoiding dangerous climate change necessitates the decarbonization of electricity systems within the next few decades. In Germany, this decarbonization is based on an increased exploitation of variable renewable electricity sources such as wind and solar power. While system security has remained constantly high, the integration of renewables causes additional costs. In 2015, the costs of grid management saw an all time high of about € 1 billion. Despite the addition of renewable capacity, these costs dropped substantially in 2016. We thus investigate the effect of natural climate variability on grid management costs in this study. We show that the decline is triggered by natural wind variability focusing on redispatch as a main cost driver. In particular, we find that 2016 was a weak year in terms of wind generation averages and the occurrence of westerly circulation weather types. Moreover, we show that a simple model based on the wind generation time series is skillful in detecting redispatch events on timescales of weeks and beyond. As a consequence, alterations in annual redispatch costs in the order of hundreds of millions of euros need to be understood and communicated as a normal feature of the current system due to natural wind variability. PMID:29329349

Natural wind variability triggered drop in German redispatch volume and costs from 2015 to 2016.

Science.gov (United States)

Wohland, Jan; Reyers, Mark; Märker, Carolin; Witthaut, Dirk

2018-01-01

Avoiding dangerous climate change necessitates the decarbonization of electricity systems within the next few decades. In Germany, this decarbonization is based on an increased exploitation of variable renewable electricity sources such as wind and solar power. While system security has remained constantly high, the integration of renewables causes additional costs. In 2015, the costs of grid management saw an all time high of about € 1 billion. Despite the addition of renewable capacity, these costs dropped substantially in 2016. We thus investigate the effect of natural climate variability on grid management costs in this study. We show that the decline is triggered by natural wind variability focusing on redispatch as a main cost driver. In particular, we find that 2016 was a weak year in terms of wind generation averages and the occurrence of westerly circulation weather types. Moreover, we show that a simple model based on the wind generation time series is skillful in detecting redispatch events on timescales of weeks and beyond. As a consequence, alterations in annual redispatch costs in the order of hundreds of millions of euros need to be understood and communicated as a normal feature of the current system due to natural wind variability.

Natural wind variability triggered drop in German redispatch volume and costs from 2015 to 2016.

Directory of Open Access Journals (Sweden)

Jan Wohland

Full Text Available Avoiding dangerous climate change necessitates the decarbonization of electricity systems within the next few decades. In Germany, this decarbonization is based on an increased exploitation of variable renewable electricity sources such as wind and solar power. While system security has remained constantly high, the integration of renewables causes additional costs. In 2015, the costs of grid management saw an all time high of about € 1 billion. Despite the addition of renewable capacity, these costs dropped substantially in 2016. We thus investigate the effect of natural climate variability on grid management costs in this study. We show that the decline is triggered by natural wind variability focusing on redispatch as a main cost driver. In particular, we find that 2016 was a weak year in terms of wind generation averages and the occurrence of westerly circulation weather types. Moreover, we show that a simple model based on the wind generation time series is skillful in detecting redispatch events on timescales of weeks and beyond. As a consequence, alterations in annual redispatch costs in the order of hundreds of millions of euros need to be understood and communicated as a normal feature of the current system due to natural wind variability.

Tracking the complete revolution of surface westerlies over Northern Hemisphere using radionuclides emitted from Fukushima

International Nuclear Information System (INIS)

Hernández-Ceballos, M.A.; Hong, G.H.; Lozano, R.L.; Kim, Y.I.; Lee, H.M.; Kim, S.H.; Yeh, S.-W.; Bolívar, J.P.; Baskaran, M.

2012-01-01

Massive amounts of anthropogenic radionuclides were released from the nuclear reactors located in Fukushima (northeastern Japan) between 12 and 16 March 2011 following the earthquake and tsunami. Ground level air radioactivity was monitored around the globe immediately after the Fukushima accident. This global effort provided a unique opportunity to trace the surface air mass movement at different sites in the Northern Hemisphere. Based on surface air radioactivity measurements around the globe and the air mass backward trajectory analysis of the Fukushima radioactive plume at various places in the Northern Hemisphere by employing the Hybrid Single-Particle Lagrangian Integrated Trajectory model, we show for the first time, that the uninterrupted complete revolution of the mid-latitude Surface Westerlies took place in less than 21 days, with an average zonal velocity of > 60 km/h. The position and circulation time scale of Surface Westerlies are of wide interest to a large number of global researchers including meteorologists, atmospheric researchers and global climate modellers. -- Highlights: ► Evidence of the South Korea contamination with released radiocesium from Fukushima. ► Field samples and air mass analysis were utilized to elucidate the transport of those radionuclides. ► Characterization of the air mass movements at different sites at the Earth's surface. ► Verification of the uninterrupted complete revolution of the artificial radionuclides released in Fukushima. ► Quantification of the velocity of the artificial radionuclides released in Fukushima.

Tracking the complete revolution of surface westerlies over Northern Hemisphere using radionuclides emitted from Fukushima

Energy Technology Data Exchange (ETDEWEB)

Hernandez-Ceballos, M.A. [Department of Applied Physics, University of Huelva, Huelva (Spain); Hong, G.H. [Korea Ocean Research and Development Institute, Ansan 426-744 (Korea, Republic of); Lozano, R.L. [Department of Applied Physics, University of Huelva, Huelva (Spain); Kim, Y.I. [Korea Ocean Research and Development Institute, Uljin 767-813 (Korea, Republic of); Lee, H.M.; Kim, S.H. [Korea Ocean Research and Development Institute, Ansan 426-744 (Korea, Republic of); Yeh, S.-W. [Department of Environmental Marine Science, Hanyang University, Ansan, 426-791 (Korea, Republic of); Bolivar, J.P., E-mail: bolivar@uhu.es [Department of Applied Physics, University of Huelva, Huelva (Spain); Baskaran, M. [Department of Geology, Wayne State University, Detroit, Michigan (United States)

2012-11-01

Massive amounts of anthropogenic radionuclides were released from the nuclear reactors located in Fukushima (northeastern Japan) between 12 and 16 March 2011 following the earthquake and tsunami. Ground level air radioactivity was monitored around the globe immediately after the Fukushima accident. This global effort provided a unique opportunity to trace the surface air mass movement at different sites in the Northern Hemisphere. Based on surface air radioactivity measurements around the globe and the air mass backward trajectory analysis of the Fukushima radioactive plume at various places in the Northern Hemisphere by employing the Hybrid Single-Particle Lagrangian Integrated Trajectory model, we show for the first time, that the uninterrupted complete revolution of the mid-latitude Surface Westerlies took place in less than 21 days, with an average zonal velocity of > 60 km/h. The position and circulation time scale of Surface Westerlies are of wide interest to a large number of global researchers including meteorologists, atmospheric researchers and global climate modellers. -- Highlights: Black-Right-Pointing-Pointer Evidence of the South Korea contamination with released radiocesium from Fukushima. Black-Right-Pointing-Pointer Field samples and air mass analysis were utilized to elucidate the transport of those radionuclides. Black-Right-Pointing-Pointer Characterization of the air mass movements at different sites at the Earth's surface. Black-Right-Pointing-Pointer Verification of the uninterrupted complete revolution of the artificial radionuclides released in Fukushima. Black-Right-Pointing-Pointer Quantification of the velocity of the artificial radionuclides released in Fukushima.

Wind power development field test project at Ashibe-cho. Detailed wind characteristics survey; Ashibecho ni okeru furyoku kaihatsu field test jigyo (fukyo seisa) hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-11-01

A detailed wind characteristics survey was conducted at Ashibe-cho, Iki-gun, Nagasaki Prefecture, on the assumption that a wind power generation system would be constructed. The survey was a 1-year project from October 1998 through September 1999, and wind characteristics such as the average wind speed, average wind direction, standard deviation of wind velocity, and the maximum instantaneous wind speed were observed. The observation point was fixed at 20m above ground, the minimum time unit for observation was 10 minutes, and the 10-minute average value was defined as the measured value. For the maximum instantaneous wind speed, the minimum time unit for observation was set to be 2 seconds. The yearly average wind speed was 5.8m/s and the maximum wind speed in the period was 35m/s. Winds came from the prevailing direction of NE (21.3%), and then from NNE (14.7%) and ENE (7.9%). The wind axis was in the NE-SW direction, and the total wind direction occurrence rate from the 6 directions was 60.2%. Turbulence intensity was 0.19 at wind speed 2.0m/s or more and 0.17 at wind speed 4.0m/s or more. Estimated wind turbine yearly operating factors of 66-84% were obtained using rated values of a 150kW, 300kW, and 750kW-class wind turbines. (NEDO)

Centennial eolian cyclicity in the Great Plains, USA: A dominant pattern of wind transport over the past 4000 years?

Science.gov (United States)

Schwalb, Antje; Dean, Walter E.; Fritz, C. Sherilyn; Geiss, Christoph E.; Kromer, Bernd

2010-01-01

Proxy evidence at decadal resolution from Late Holocene sediments from Pickerel Lake, northeastern South Dakota, shows distinct centennial cycles (400-700 years) in magnetic susceptibility; contents of carbonate, organic carbon, and major elements; abundance in ostracodes; and delta18O and delta13C values in calcite. Proxies indicate cyclic changes in eolian input, productivity, and temperature. Maxima in magnetic susceptibility are accompanied by maxima in aluminum and iron mass accumulation rates (MARs), and in abundances of the ostracode Fabaeformiscandona rawsoni. This indicates variable windy, and dry conditions with westerly wind dominance, including during the Medieval Climate Anomaly. Maxima in carbonates, organic carbon, phosphorous, and high delta13C values of endogenic calcite indicate moister and less windy periods with increased lake productivity, including during the Little Ice Age, and alternate with maxima of eolian transport. Times of the Maunder, Sporer and Wolf sunspot minima are characterized by maxima in delta18O values and aluminum MARs, and minima in delta13C values and organic carbon content. We interpret these lake conditions during sunspot minima to indicate decreases in lake surface water temperatures of up to 4-5 degrees C associated with decreases in epilimnetic productivity during summer. We propose that the centennial cycles are triggered by solar activity, originate in the tropical Pacific, and their onset during the Late Holocene is associated with insolation conditions driven by precession. The cyclic pattern is transmitted from the tropical Pacific into the atmosphere and transported by westerly winds into the North Atlantic realm where they strengthen the Atlantic Meridional Overturning Circulation during periods of northern Great Plains wind maxima. This consequently leads to moister climates in Central and Northern Europe. Thus, Pickerel Lake provides evidence for mechanisms of teleconnections including an atmospheric link

Atmospheric circulation over the Bolivian Altiplano during dry and wet periods and extreme phases of the Southern Oscillation

Science.gov (United States)

Vuille, M.

1999-11-01

The atmospheric circulation over the Bolivian Altiplano during composite WET and DRY periods and during HIGH and LOW index phases of the Southern Oscillation was investigated using daily radiosonde data from Antofagasta (Chile), Salta (Argentina), Lima (Peru) and La Paz (Bolivia), daily precipitation data from the Bolivian/Chilean border between 18° and 19°S and monthly NCEP (National Centers for Environmental Prediction) reanalysis data between 1960 and 1998. In austral summer (DJF) the atmosphere during WET periods is characterized by easterly wind anomalies in the middle and upper troposphere over the Altiplano, resulting in increased moisture influx from the interior of the continent near the Altiplano surface. The Bolivian High is intensified and displaced southward. On the other hand, westerly winds usually prevail during DRY summer periods, preventing the moisture transport from the east from reaching the western Altiplano. Precipitation tends to be deficient over the western Bolivian Altiplano during LOW index summers and above average during HIGH and LOW+1 summers, but the relation is weak and statistically insignificant. LOW summers feature broadly similar atmospheric circulation anomalies as DRY periods and can be regarded as an extended DRY period or as a summer with increased occurrence of DRY episodes. HIGH summers, and to a lesser degree LOW+1 summers, are characterized by broadly opposite atmospheric characteristics, featuring a more pronounced Bolivian High located significantly further south, and easterly wind anomalies over the Altiplano. In winter (JJA) precipitation events are rare; these are associated with increased northerly and westerly wind components, reduced pressure and temperature, and increased specific humidity over the entire Altiplano. Atmospheric circulation anomalies during LOW periods are less pronounced in austral winter (JJA) than in summer, but generally feature similar changes (increased temperatures and a vertically

Wind erosion on Deliblato (the largest European continental sandy terrain) studied using 210Pbex and 137Cs measurements

International Nuclear Information System (INIS)

Krmar, M.; Hansman, J.; Todorovic, N.; Mihailovic, A.; Vucinic-Vasic, M.; Savic, R.

2015-01-01

The objective of this paper is to estimate the difference in wind erosion between two extreme situations: sandy soil permanently covered by grass and the nearby frequently ploughed area highly susceptible to wind erosion. The spatial pattern of soil erosion rate was investigated using 137 Cs and 210 Pb ex tracing technique. The spatial pattern of erosion rate obtained within the studied area reveal influence of topography as well as direction of prevailing winds on mobilization and transport of the soil particles. (author)

Summary Report: The Shadow effect of large wind farms: measurements, data analysis and modelling

DEFF Research Database (Denmark)

Frandsen, Sten Tronæs; Barthelmie, Rebecca Jane; Rathmann, Ole

It was the goal of the project – by means of data from the demonstration wind farms Horns Rev and Nysted, analyses of these data and modelling – to facilitate prediction of the power losses from a wind farm should a new wind farm be built upwind relative to the prevailing wind direction...... it may appropriate to build new wind farms rather close to the existing wind farms. A relevant question is therefore how far away new wind farms must be placed to avoid too large power losses. Measurements have been carried out for several years at the two sites, and databases have been prepared....... Thus, if different modelling efforts results in comparable results, the quality of the models will be tested outside the physical range where data are available. All considered the project participants find that the project has been immensely successful. The main achievements of the project are...

Wind power development field test project at Okkobe-cho. Close survey on wind conditions; Okkobecho ni okeru furyoku kaihatsu field test jigyo (fukyo seisa) hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-11-01

A survey was made on regional wind conditions on the assumption that a wind power generator was installed around Okkobe Rakuno-no-oka, Okkobe-cho, Monbetsu-gun, Hokkaido. The survey period was one year from Oct., 1998 to Sept., 1999. The observations were carried out on the average wind velocity, average wind direction, standard deviation of velocity, and the maximum instantaneous wind velocity. With a fixed point observation at 20 m above ground, and with the minimum observation time unit of 10 minutes, an average value during the 10 minutes was determined as the measurement of each category. However, the maximum instantaneous wind velocity was determined on the measurement with the minimum observation time unit of 2 seconds. The average wind velocity was 4.8 m/s, the maximum wind velocity during the period was 29.9 m/s, the prevailing wind direction was WSW (17.1%), the wind axis was WSW-ENE, and the total occurrence rate of wind direction was 51.1%. The intensity of turbulence was 0.19 at a wind velocity of 2.0 m/s or above and was 0.16 at 4.0 m/s or above. An estimated annual operation rate of a windmill was 59-77% using the rated value of a 150 kW, 300 kW and 750 kW class windmills. (NEDO)

75 FR 18552 - Federal Prevailing Rate Advisory Committee; Open Committee Meetings

Science.gov (United States)

2010-04-12

... of Personnel Management Building, 1900 E Street, NW., Washington, DC. The Federal Prevailing Rate... business. Therefore, these caucuses will be closed to the public because of a determination made by the..., Federal Prevailing Rate Advisory Committee, Room 5H27, 1900 E Street, NW., Washington, DC 20415, (202) 606...

Subantarctic peatlands and their potential as palaeoenvironmental and palaeoclimatic archives

NARCIS (Netherlands)

Van der Putten, N.; Mauquoy, D.; Verbruggen, C.; Björck, S.

2012-01-01

Subantarctic islands are located within the Antarctic Circumpolar Current and the southern westerly wind belt, the latter called Southern Westerlies, making them unique terrestrial archives to investigate past changes in oceanic and atmospheric circulation patterns in the southern mid-latitudes. The

Optimization of monopiles for offshore wind turbines.

Science.gov (United States)

Kallehave, Dan; Byrne, Byron W; LeBlanc Thilsted, Christian; Mikkelsen, Kristian Kousgaard

2015-02-28

The offshore wind industry currently relies on subsidy schemes to be competitive with fossil-fuel-based energy sources. For the wind industry to survive, it is vital that costs are significantly reduced for future projects. This can be partly achieved by introducing new technologies and partly through optimization of existing technologies and design methods. One of the areas where costs can be reduced is in the support structure, where better designs, cheaper fabrication and quicker installation might all be possible. The prevailing support structure design is the monopile structure, where the simple design is well suited to mass-fabrication, and the installation approach, based on conventional impact driving, is relatively low-risk and robust for most soil conditions. The range of application of the monopile for future wind farms can be extended by using more accurate engineering design methods, specifically tailored to offshore wind industry design. This paper describes how state-of-the-art optimization approaches are applied to the design of current wind farms and monopile support structures and identifies the main drivers where more accurate engineering methods could impact on a next generation of highly optimized monopiles. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

7 CFR 27.35 - Lower class of two samples to prevail.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Lower class of two samples to prevail. 27.35 Section 27.35 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE... Micronaire Determinations § 27.35 Lower class of two samples to prevail. In case a sample drawn from one...

Influences of some parameters on the performance of a small vertical axis wind turbine

Directory of Open Access Journals (Sweden)

Dumitrache Alexandru

2016-01-01

Full Text Available The effects of various parameters on the performance of a straight bladed vertical axis wind turbine, using the vortex model, have been numerically investigated. A vortex model has been used to evaluate the performance of a vertical axis wind turbine, by means of aerodynamic characteristics of different airfoils for Reynolds numbers between 105 and 106. Parameters such as the thickness and the camber of the blade airfoil, the solidity, the type of blade profile, the number of blades and the pitch angle, which influence the power coefficient, CP, and the start-up regime. This study can be used in the designing an optimal vertical axis wind turbine in a specific location, when the prevailed wind regime is known.

K/sub Ic/ and J/sub Ic/ of Westerly granite: effects of thickness and in-plane dimensions

International Nuclear Information System (INIS)

Schmidt, R.A.; Lutz, T.J.

1978-01-01

An investigation is described in which tensile properties, fracture toughness, and critical J integral are measured for Westerly granite, a rock that is widely used in rock mechanics studies. This was primarily a parameter sensitivity study in which the effects of specimen dimensions and testing techniques were assessed. It is hoped that this study will aid in establishing tentative standards and guidelines for fracture toughness testing of rock as well as indicate the feasibility of using a J integral fracture criterion for this material. ASTM standard specimen configurations of the compact and bend types were tested with compact specimens ranging in width from W = 25.4 mm to W = 406.4 mm (0.5T to 8T) and with thickness ranging from 13 mm to 100 mm. A series of 4T compact specimens were tested to assess the effects of thickness and fatigue precracking. Techniques are described that enable several values of K/sub Ic/, a complete J vs crack growth curve, and a J/sub Ic/ value to be obtained from each sample. Direct-pull tension tests on shaped specimens of Westerly granite are described which indicate a high degree of nonlinear, inelastic behavior. This fact raises questions about the use of LEFM, but the J/sub Ic/ data presented appear to validate the K/sub Ic/ measurements

Wind power development field test project at Kodomari-mura 'Marinetopia'. Close survey on wind conditions; Kodomarimura Marinetopia ni okeru furyoku kaihatsu field test jigyo (fukyo seisa) hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-11-01

A survey was made on wind conditions in Imabetsu-machi, Higashi Tsugaru-gun, Aomori prefecture, on the assumption that a wind power generation system was installed therein. The survey period was one year from Oct., 1998 to Sept., 1999. The observations were carried out on the average wind velocity, average wind direction, standard deviation of velocity, and the maximum instantaneous wind velocity. With a fixed point observation at 20 m above ground, and with the minimum observation time unit of 10 minutes, an average value during the 10 minutes was determined as the measurement of each category. However, the maximum instantaneous wind velocity was determined on the measurement with the minimum observation time unit of 2 seconds. The annual average wind velocity was 4.8 m/s, the maximum wind velocity during the period was 35 m/s, the prevailing wind direction was NW-WNW and ESE-SEW, and the occurrence rate of wind direction at the wind axis of NW-SE was 88.1%. The intensity of turbulence was 0.24 at a wind velocity of 2.0 m/s or above and was 0.20 at 4.0 m/s or above. An estimated annual operation rate of a windmill was 46-64% using the rated value of a 150 kW, 300 kW and 750 kW class windmills. (NEDO)

Wind potential data analysis based on on-site measurements with tall meteorological masts installed in northern Bulgaria

International Nuclear Information System (INIS)

Terziev, A.; Genovski, I.; Petrov, P.; Valchev, V.

2010-01-01

The current work has studied the possibility of correlation between wind data collected with tall meteorological masts in Northern Bulgaria. The processed data were collected for the same time period. The analysis is based on daily wind data. The correlation was made taking into consideration the following factors: the height of carried wind measurements, the prevailing wind direction, and the surface roughness of the relief. The analysis of the distance effect between meteorological masts is also considered. The possibility of modeling the wind velocity field for the area limited by the meteorological mast locations is examined. For this purpose for wind speed velocity field description is used triangulation with linear interpolation between the data. Data interpolation was made based on compulsory condition for relative flatness of the terrain. (authors)

Triangularly arranged heat exchanger bundles to restrain wind effects on natural draft dry cooling system

International Nuclear Information System (INIS)

Liao, H.T.; Yang, L.J.; Du, X.Z.; Yang, Y.P.

2016-01-01

Highlights: • Triangularly arranged heat exchanger around the dry-cooling tower is proposed. • By coupling condenser with dry cooling system, TACHE performance is obtained. • At low wind speeds, cooling performance with TACHE is inferior to that with CACHE. • Better performance can be achieved for cooling system with TACHE at high wind speeds. • TACHE can be applied to the region with the strong prevailing wind all year around. - Abstract: It has been commonly recognized that the crosswind may deteriorate the cooling performance of the natural draft dry cooling system with vertically arranged heat exchanger bundles around the circumference of dry-cooling tower. With the purpose for restraining the adverse effects of ambient winds, a novel triangular configuration of heat exchanger bundles is proposed in this work. The air-side flow and heat transfer models coupled with the circulating water heat transfer process are developed for two kinds of natural draft dry cooling systems with the conventional circularly arranged and novel triangularly arranged heat exchanger bundles, by which the flow and temperature fields, mass flow rate of cooling air, outlet water temperature of heat exchanger and turbine back pressure are obtained. Three wind directions of 0°, 90°, and 180° are investigated at various wind speeds for the natural draft dry cooling system with triangularly arranged heat exchanger bundles, which are compared with the conventional system with circularly arranged heat exchanger bundles. The results show that the thermo-flow performances of the natural draft dry cooling system with triangularly arranged heat exchanger get improved significantly at high wind speeds and in the wind direction of 180°, thus a low turbine back pressure can be achieved, which is of benefit to the energy efficiency of the power generating unit. The natural draft dry cooling system with triangularly arranged heat exchanger is recommended to apply to the regions with

PREVAIL-EPL alpha tool electron optics subsystem

Science.gov (United States)

Pfeiffer, Hans C.; Dhaliwal, Rajinder S.; Golladay, Steven D.; Doran, Samuel K.; Gordon, Michael S.; Kendall, Rodney A.; Lieberman, Jon E.; Pinckney, David J.; Quickle, Robert J.; Robinson, Christopher F.; Rockrohr, James D.; Stickel, Werner; Tressler, Eileen V.

2001-08-01

The IBM/Nikon alliance is continuing pursuit of an EPL stepper alpha tool based on the PREVAIL technology. This paper provides a status report of the alliance activity with particular focus on the Electron Optical Subsystem developed at IBM. We have previously reported on design features of the PREVAIL alpha system. The new state-of-the-art e-beam lithography concepts have since been reduced to practice and turned into functional building blocks of a production level lithography tool. The electron optical alpha tool subsystem has been designed, build, assembled and tested at IBM's Semiconductor Research and Development Center (SRDC) in East Fishkill, New York. After demonstrating subsystem functionality, the electron optical column and all associated control electronics hardware and software have been shipped during January 2001 to Nikon's facility in Kumagaya, Japan, for integration into the Nikon commercial e-beam stepper alpha tool. Early pre-shipment results obtained with this electron optical subsystem are presented.

Wind power development field test project at Rokkasho-mura, Aomori prefecture. Close survey on wind conditions; Aomoriken Rokkashomura ni okeru furyoku kaihatsu field test jigyo (fukyo seisa) hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-11-01

A survey was made on wind conditions in Rokkasho-mura, Kamikita-gun, Aomori prefecture, on the assumption that a wind power generation system was installed therein. The survey period was one year from Oct., 1998 to Sept., 1999. The observations were carried out on the average wind velocity, average wind direction, standard deviation of velocity, and the maximum instantaneous wind velocity. With a fixed point observation at 20 m above ground, and with the minimum observation time unit of 10 minutes, an average value during the 10 minutes was determined as the measurement of each category. However, the maximum instantaneous wind velocity was determined on the measurement with the minimum observation time unit of 2 seconds. The annual average wind velocity was 4.6 m/s, the maximum wind velocity during the period was 26.0 m/s, the prevailing wind direction was NW (20.8%), WNW (18.0%), and SE (13.5%), and the total occurrence rate of wind direction at the wind axis of NW-SE was 75.7%. The intensity of turbulence was 0.25 at a wind velocity of 2.0 m/s or above and was 0.21 at 4.0 m/s or above. An estimated annual operation rate of a windmill was 59-72% using the rated value of a 150 kW, 300 kW and 750 kW class windmills. (NEDO)

An assessment of wind energy potential in Iberia under climate change

Science.gov (United States)

Liberato, Margarida L. R.; Santos, João A.; Rochinha, Carlos; Reyers, Mark; Pinto, Joaquim G.

2015-04-01

Wind energy potential in Iberia is assessed for recent-past (1961-2000) and future (2041-2070) climates. For recent-past, a COSMO-CLM simulation driven by ERA-40 is used. COSMO-CLM simulations driven by ECHAM5 following the A1B scenario are used for future projections. A 2 MW rated power wind turbine is selected. Mean potentials, inter-annual variability and irregularity are discussed on annual/seasonal scales and on a grid resolution of 20 km. For detailed regional assessments eight target sites are considered. For recent-past conditions, the highest daily mean potentials are found in winter over northern and eastern Iberia, particularly on high-elevation or coastal regions. In northwestern Iberia, daily potentials frequently reach maximum wind energy output (50 MWh day-1), particularly in winter. Southern Andalucía reveals high potentials throughout the year, whereas the Ebro valley and central-western coast show high potentials in summer. The irregularity in annual potentials is moderate (2 MWh day-1). The northward displacement of North Atlantic westerly winds (autumn-spring) and the strengthening of easterly flows (summer) are key drivers of future projections. Santos, J.A.; Rochinha, C.; Liberato, M.L.R.; Reyers, M.; Pinto, J.G. (2015) Projected changes in wind energy potentials over Iberia. Renewable Energy, 75, 1: 68-80. doi: 10.1016/j.renene.2014.09.026 Acknowledgements: This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER-019524 (PTDC/AAC-CLI/121339/2010).

Effect of wind turbine wakes on summer-time wind profiles in the US Great Plains

Science.gov (United States)

Rhodes, M. E.; Lundquist, J. K.; Aitken, M.

2011-12-01

Wind energy is steadily becoming a significant source of grid electricity in the United States, and the Midwestern United States provides one of the nation's richest wind resources. This study examines the effect of wind turbine wakes on the wind profile in central Iowa. Data were collected using a coherent Doppler LiDAR system located approximately 2.5 rotor diameters north of a row of modern multi-MW wind turbine generators. The prevailing wind direction was from the South allowing the LiDAR to capture wind turbine wake properties; however, a number of periods existed where the LiDAR captured undisturbed flow. The LiDAR system reliably obtained readings up to 200 m above ground level (AGL), spanning the entire rotor disk (~40 m to 120 m AGL) which far surpasses the information provided by traditional wind resource assessment instrumentation. We extract several relevant parameters from the lidar data including: horizontal wind speed, vertical velocity, horizontal turbulence intensity, wind shear, and turbulent kinetic energy (TKE). Each time period at a particular LiDAR measurement height was labeled "wake" or "undisturbed" based on the wind direction at that height. Wake and undisturbed data were averaged separately to create a time-height cross-section averaged day for each parameter. Significant differences between wake and undisturbed data emerge. During the day, wake conditions experience larger values of TKE within the altitudes of the turbine rotor disk while TKE values above the rotor disk are similar between waked and undisturbed conditions. Furthermore, the morning transition of TKE in the atmospheric boundary layer commences earlier during wake conditions than in undisturbed conditions, and the evening decay of TKE persists longer during wake conditions. Waked wind shear is consistently greater than undisturbed periods at the edges of the wind turbine rotor disk (40m & 120m AGL), but especially so during the night where wind shear values during wake

Equatorial jet - a case study

Digital Repository Service at National Institute of Oceanography (India)

Muraleedharan, P.M.; PrasannaKumar, S.

analysis of hydrographic data of 1964 is also carried out to understand the response signature of water column to prevailing westerlies. A jet forms in the Central Indian Ocean which gathers momentum as it advances eastward. Sinking of the thermocline...

WIND SPEED Monitoring in Northern Eurasia

Science.gov (United States)

Bulygina, O.; Korshunova, N. N.; Razuvaev, V. N.; Groisman, P. Y.

2016-12-01

The wind regime of Russia varies a great deal due to the large size of the country's territory and variety of climate and terrain conditions. Changes in the regime of surface wind are of great practical importance. They can affect heat and water balance. Strong wind is one of the most hazardous meteorological event for various sectors of economy and for infrastructure. The main objective of this research is to monitoring wind speed change in Northern Eurasia At meteorological stations wind speed and wind direction are measured at the height of 10-12 meters over the land surface with the help of wind meters or wind wanes. Calculations were made on the basis of data for the period of 1980-2015. It allowed the massive scale disruption of homogeneity to be eliminated and sufficient period needed to obtain sustainable statistic characteristics to be retained. Data on average and maximum wind speed measured at 1457 stations of Russia were used. The analysis of changes in wind characteristics was made on the basis of point data and series of average characteristics obtained for 18 quasi-homogeneous climatic regions. Statistical characteristics (average and maximum values of wind speed, prevailing wind direction, values of the boundary of the 90%, 95% and 99%-confidence interval in the distribution of maximum wind speed) were obtained for all seasons and for the year as a whole. Values of boundaries of the 95% and 99%-confidence interval in the distribution of maximum wind speed were considered as indicators of extremeness of the wind regime. The trend of changes in average and maximum wind speed was assessed with a linear trend coefficient. A special attention was paid to wind changes in the Arctic where dramatic changes in surface air temperature and sea ice extent and density have been observed during the past decade. The analysis of the results allowed seasonal and regional features of changes in the wind regime on the territory of the northern part of Eurasia to be

76 FR 9694 - Prevailing Rate Systems; Redefinition of the Northeastern Arizona and Colorado Appropriated Fund...

Science.gov (United States)

2011-02-22

... 3206-AM33 Prevailing Rate Systems; Redefinition of the Northeastern Arizona and Colorado Appropriated... changes are based on recent consensus recommendations of the Federal Prevailing Rate Advisory Committee to... Northeastern Arizona wage area. The Federal Prevailing Rate Advisory Committee (FPRAC), the national labor...

Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Data report 2001

International Nuclear Information System (INIS)

Leonhard, S.B.; Pedersen, John

2002-08-01

The Ministry of Environment and Energy requested ELSAM and ELTRA to establish an offshore wind farm with an output of 150 MW in the waters of Horns Rev, approximately 15 km off Blaevandshuk, which is the most westerly point of Denmark. The first phase of construction of the wind farm have started in spring 2002. Before the construction activities take place, a baseline description of the benthos has been conducted as a part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines for offshore wind farms prepared by the Danish Energy Agency. The monitoring programme established for the benthic infauna was performed in spring 2001. In addition to a proposed fish investigation programme concerning the stomach contents of fish a comparative programme on benthos was established as part of the monitoring programme. The benthos sampling in connection with the fish programme was conducted in autumn 2001. This benthic survey includes sampling in a proposed reference area for the fish surveys north east of the wind farm. This report presents the data of the baseline environmental survey of the seabed in the wind farm site and in the proposed reference site and a brief description of the weather conditions at the time of sampling. (au)

Source-receptor relationships for PM2.5 during typical pollution episodes in the Pearl River Delta city cluster, China

Science.gov (United States)

Fan, Q.; Liu, Y.; Hong, Y.; Wang, X.; Chan, P.; Chen, X.; Lai, A.; Wang, M.; Chen, X.

2017-12-01

Located in the Southern China monsoon region, pollution days in Pearl River Delta (PRD) were classified into "Western type", "Central type" or "Eastern type", with a relative percentage of 67%, 24% and 9%, respectively. Using this classification system, three typical pollution events were selected for numerical simulations using the WRF-Chem model. The source sensitivity method for anthropogenic emissions of PM2.5 and its precursors was applied to identify the source-receptor relationships for PM2.5 among 9 cities in PRD. For "Western type" case, the PRD region was under control of a high-pressure system with easterly prevailing winds. The PM2.5 concentrations in the western PRD region were higher than those in the eastern region, with emissions from cities in the eastern PRD region having higher contributions. Within the PRD's urban cluster, PM2.5 in Huizhou, Dongguan and Shenzhen was mainly derived from local emissions, whereas the PM2.5 in the other cities was primarily derived from external transport. For "Eastern type" case, the PRD was influenced by Typhoon Soulik with westerly prevailing winds. Emissions from cities in the western PRD region had the highest impacts on the overall PM2.5 concentration. PM2.5 in Jiangmen and Foshan was primarily derived from local emissions. Regarding "Central type" case, the PRD region was under control of a uniform pressure field with low wind speed. PM2.5 concentrations of each city were primarily caused by local emissions. Overall, wind flows played a significant role in the transport and spatial distribution of PM2.5 across the PRD region. Ideally, local governments would be wise to establish joint prevention and control measures to reduce regional atmospheric pollution, especially for "Western type" pollution.

Assessment of Global Wind Energy Resource Utilization Potential

Science.gov (United States)

Ma, M.; He, B.; Guan, Y.; Zhang, H.; Song, S.

2017-09-01

Development of wind energy resource (WER) is a key to deal with climate change and energy structure adjustment. A crucial issue is to obtain the distribution and variability of WER, and mine the suitable location to exploit it. In this paper, a multicriteria evaluation (MCE) model is constructed by integrating resource richness and stability, utilization value and trend of resource, natural environment with weights. The global resource richness is assessed through wind power density (WPD) and multi-level wind speed. The utilizable value of resource is assessed by the frequency of effective wind. The resource stability is assessed by the coefficient of variation of WPD and the frequency of prevailing wind direction. Regression slope of long time series WPD is used to assess the trend of WER. All of the resource evaluation indicators are derived from the atmospheric reanalysis data ERA-Interim with spatial resolution 0.125°. The natural environment factors mainly refer to slope and land-use suitability, which are derived from multi-resolution terrain elevation data 2010 (GMTED 2010) and GlobalCover2009. Besides, the global WER utilization potential map is produced, which shows most high potential regions are located in north of Africa. Additionally, by verifying that 22.22 % and 48.8 9% operational wind farms fall on medium-high and high potential regions respectively, the result can provide a basis for the macroscopic siting of wind farm.

Wintertime slope winds and its turbulent characteristics in the Yeongdong region of Korea

Science.gov (United States)

Jeon, H. R.; Eun, S. H.; Kim, B. G.; Lee, Y. H.

2015-12-01

The Yeongdong region has various meteorological phenomenons by virtue of complicated geographical characteristics with high Taebaek Mountains running from the north to the south and an adjacent East Sea to the east. There are few studies on the slope winds and its turbulent characteristics over the complex terrain, which are critical information in mountain climbing, hiking, paragliding, even winter sports such as alpine skiing and ski jump etc. For the understanding of diverse mountain winds in the complex terrain in Yeongdong, hot-wire anemometers (Campbell Scientific) have been installed at a couple of sites since October 2014 and several automatic weather stations at several sites around the mountainous region in Yeongdong since November 2012.WRF model simulations have been also done with an ultra-fine horizontal resolution of 300 m for 10 years. Generally, model and observation show that the dominant wind is westerly, approximately more than 75%. It is quite consistent that wind fields from both model and observation agree with each other in the valley region and at the top of the mountain, but there is a significant disagreement in wind direction specifically in the slide slope. Probably this implies model's performance with even an ultra-fine resolution is still not enough for the slide slope domain of complex terrains. Despite that, the observation clearly showed up- and down slope winds for the weak synoptic conditions carefully selected such as strong insolation and a synoptic wind less than 5m/s in the 850 hPa. The up- and down slope flows are also demonstrated in the snow-covered condition as well as grass ground. Further, planar fit transformation algorithm against the coordinate tilt has been applied to raw wind data (10Hz) of the slope site for the analysis of turbulence properties. Turbulence also increases with synoptic wind strength. Detailed analysis of mechanical turbulence and buoyance will be discussed for different surface properties (grass

76 FR 70321 - Prevailing Rate Systems; Redefinition of the Northern Mississippi and Memphis, TN, Appropriated...

Science.gov (United States)

2011-11-14

... OFFICE OF PERSONNEL MANAGEMENT 5 CFR Part 532 RIN 3206-AM37 Prevailing Rate Systems; Redefinition... on a consensus recommendation of the Federal Prevailing Rate Advisory Committee (FPRAC) to best match... which OPM received no comments. The Federal Prevailing Rate Advisory Committee (FPRAC), the national...

Temperature And Wind Velocity Oscillations Along a Gentle Slope During Sea-Breeze Events

Science.gov (United States)

Bastin, Sophie; Drobinski, Philippe

2005-03-01

The flow structure on a gentle slope at Vallon d’Ol in the northern suburbs of Marseille in southern France has been documented by means of surface wind and temperature measurements collected from 7 June to 14 July 2001 during the ESCOMPTE experiment. The analysis of the time series reveals temperature and wind speed oscillations during several nights (about 60--90 min oscillation period) and several days (about 120-180 min oscillation period) during the whole observing period. Oscillating katabatic winds have been reported in the literature from theoretical, experimental and numerical studies. In the present study, the dynamics of the observed oscillating katabatic winds are in good agreement with the theory.In contrast to katabatic winds, no daytime observations of oscillating anabatic upslope flows have ever been published to our knowledge, probably because of temperature inversion break-up that inhibits upslope winds. The present paper shows that cold air advection by a sea breeze generates a mesoscale horizontal temperature gradient, and hence baroclinicity in the atmosphere, which then allows low-frequency oscillations, similar to a katabatic flow. An expression for the oscillation period is derived that accounts for the contribution of the sea-breeze induced mesoscale horizontal temperature gradient. The theoretical prediction of the oscillation period is compared to the measurements, and good agreement is found. The statistical analysis of the wind flow at Vallon d’Ol shows a dominant north-easterly to easterly flow pattern for nighttime oscillations and a dominant south-westerly flow pattern for daytime oscillations. These results are consistent with published numerical simulation results that show that the air drains off the mountain along the maximum slope direction, which in the studied case is oriented south-west to north-east.

78 FR 18252 - Prevailing Rate Systems; North American Industry Classification System Based Federal Wage System...

Science.gov (United States)

2013-03-26

...-AM78 Prevailing Rate Systems; North American Industry Classification System Based Federal Wage System... applicable sections. The Federal Prevailing Rate Advisory Committee, the national labor- management committee... proposing to amend 5 CFR part 532 as follows: PART 532--PREVAILING RATE SYSTEMS 0 1. The authority citation...

76 FR 31885 - Prevailing Rate Systems; Redefinition of the Northern Mississippi and Memphis, TN, Appropriated...

Science.gov (United States)

2011-06-02

... OFFICE OF PERSONNEL MANAGEMENT 5 CFR Part 532 RIN 3206-AM37 Prevailing Rate Systems; Redefinition... Prevailing Rate Advisory Committee (FPRAC) to best match the county proposed for redefinition to a nearby FWS... Memphis wage area. The Federal Prevailing Rate Advisory Committee (FPRAC), the national labor-management...

Root architecture and wind-firmness of mature Pinus pinaster.

Science.gov (United States)

Danjon, Frédéric; Fourcaud, Thierry; Bert, Didier

2005-11-01

This study aims to link three-dimensional coarse root architecture to tree stability in mature timber trees with an average of 1-m rooting depth. Undamaged and uprooted trees were sampled in a stand damaged by a storm. Root architecture was measured by three-dimensional (3-D) digitizing. The distribution of root volume by root type and in wind-oriented sectors was analysed. Mature Pinus pinaster root systems were organized in a rigid 'cage' composed of a taproot, the zone of rapid taper of horizontal surface roots and numerous sinkers and deep roots, imprisoning a large mass of soil and guyed by long horizontal surface roots. Key compartments for stability exhibited strong selective leeward or windward reinforcement. Uprooted trees showed a lower cage volume, a larger proportion of oblique and intermediate depth horizontal roots and less wind-oriented root reinforcement. Pinus pinaster stability on moderately deep soils is optimized through a typical rooting pattern and a considerable structural adaptation to the prevailing wind and soil profile.

Winds Measured by the Rover Environmental Monitoring Station (REMS) During the Mars Science Laboratory (MSL) Rover's Bagnold Dunes Campaign and Comparison with Numerical Modeling Using MarsWRF

Science.gov (United States)

Newman, Claire E.; Gomez-Elvira, Javier; Marin, Mercedes; Navarro, Sara; Torres, Josefina; Richardson, Mark I.; Battalio, J. Michael; Guzewich, Scott D.; Sullivan, Robert; de la Torre, Manuel;

Horns Rev offshore wind farm. Environmental impact assessment of sea bottom and marine biology

Energy Technology Data Exchange (ETDEWEB)

Leonhard, S.B.

2000-03-15

An Environmental Impact Assessment (EIA) of a planned 150 MW offshore wind farm at Horns Rev has been carried out for the marine biology and sea bottom in the area, and includes vegetation and benthic fauna. The study forms part of a total EIA of the planned offshore wind farm. This EIA study has been drawn up in accordance with the guidelines laid down by the Ministry of Environment and Energy in the publication, 'Guidelines for preparation of EIAstudies for offshore wind farms. Horns Rev is situated off Blaevands Huk, which is Denmark's most westerly point. It is a shallow reef with water depths between 2 and 9 metres and is primarily composed of sand, gravel and pebbles. The area designated for the wind farm lies directly south of Horns Rev and is dominated by sand with a median particle size of 0.3 mm. Along the edges, towards areas of greater depth, the particle size increases. There are areas of fine sand in the deepest area, and in isolated pockets within the proposed wind farm site. The sediment is characterised by a very low (<1%) organic matter content. On the basis of the expected impact from the establishment of the wind farm, it is not deemed necessary to carry out special programmes during the construction phase for monitoring of the environmental-biological conditions. A monitoring and control programme is recommended during the production phase in order to follow the copper concentration in bivalves, or alternatively to initiate recovery or elimination of the copper-laden waste. A control programme is recommended during the production phase in order to follow the establishment and succession of the fouling community on the wind turbine foundations and scour-protecting revetments. (BA)

Horns Rev offshore wind farm. Environmental impact assessment of sea bottom and marine biology

Energy Technology Data Exchange (ETDEWEB)

Leonhard, S B

2000-03-15

An Environmental Impact Assessment (EIA) of a planned 150 MW offshore wind farm at Horns Rev has been carried out for the marine biology and sea bottom in the area, and includes vegetation and benthic fauna. The study forms part of a total EIA of the planned offshore wind farm. This EIA study has been drawn up in accordance with the guidelines laid down by the Ministry of Environment and Energy in the publication, 'Guidelines for preparation of EIAstudies for offshore wind farms. Horns Rev is situated off Blaevands Huk, which is Denmark's most westerly point. It is a shallow reef with water depths between 2 and 9 metres and is primarily composed of sand, gravel and pebbles. The area designated for the wind farm lies directly south of Horns Rev and is dominated by sand with a median particle size of 0.3 mm. Along the edges, towards areas of greater depth, the particle size increases. There are areas of fine sand in the deepest area, and in isolated pockets within the proposed wind farm site. The sediment is characterised by a very low (<1%) organic matter content. On the basis of the expected impact from the establishment of the wind farm, it is not deemed necessary to carry out special programmes during the construction phase for monitoring of the environmental-biological conditions. A monitoring and control programme is recommended during the production phase in order to follow the copper concentration in bivalves, or alternatively to initiate recovery or elimination of the copper-laden waste. A control programme is recommended during the production phase in order to follow the establishment and succession of the fouling community on the wind turbine foundations and scour-protecting revetments. (BA)

Solar wind ion trends and signatures: STEREO PLASTIC observations approaching solar minimum

Directory of Open Access Journals (Sweden)

A. B. Galvin

2009-10-01

Full Text Available STEREO has now completed the first two years of its mission, moving from close proximity to Earth in 2006/2007 to more than 50 degrees longitudinal separation from Earth in 2009. During this time, several large-scale structures have been observed in situ. Given the prevailing solar minimum conditions, these structures have been predominantly coronal hole-associated solar wind, slow solar wind, their interfaces, and the occasional transient event. In this paper, we extend earlier solar wind composition studies into the current solar minimum using high-resolution (1-h sampling times for the charge state analysis. We examine 2-year trends for iron charge states and solar wind proton speeds, and present a case study of Carrington Rotation 2064 (December 2007 which includes minor ion (He, Fe, O kinetic and Fe composition parameters in comparison with proton and magnetic field signatures at large-scale structures observed during this interval.

75 FR 58339 - Prevailing Rate Systems; Redefinition of the Shreveport, LA; Texarkana, TX; Milwaukee, WI; and...

Science.gov (United States)

2010-09-24

... 3206-AM28 Prevailing Rate Systems; Redefinition of the Shreveport, LA; Texarkana, TX; Milwaukee, WI... area. These changes are based on recent consensus recommendations of the Federal Prevailing Rate... below. The Federal Prevailing Rate Advisory Committee (FPRAC), the national labor-management committee...

Crater Mound Formation by Wind Erosion on Mars

Science.gov (United States)

Steele, L. J.; Kite, E. S.; Michaels, T. I.

2018-01-01

Most of Mars' ancient sedimentary rocks by volume are in wind-eroded sedimentary mounds within impact craters and canyons, but the connections between mound form and wind erosion are unclear. We perform mesoscale simulations of different crater and mound morphologies to understand the formation of sedimentary mounds. As crater depth increases, slope winds produce increased erosion near the base of the crater wall, forming mounds. Peak erosion rates occur when the crater depth is ˜2 km. Mound evolution depends on the size of the host crater. In smaller craters mounds preferentially erode at the top, becoming more squat, while in larger craters mounds become steeper sided. This agrees with observations where smaller craters tend to have proportionally shorter mounds and larger craters have mounds encircled by moats. If a large-scale sedimentary layer blankets a crater, then as the layer recedes across the crater it will erode more toward the edges of the crater, resulting in a crescent-shaped moat. When a 160 km diameter mound-hosting crater is subject to a prevailing wind, the surface wind stress is stronger on the leeward side than on the windward side. This results in the center of the mound appearing to "march upwind" over time and forming a "bat-wing" shape, as is observed for Mount Sharp in Gale crater.

Solar wind dynamic pressure variations and transient magnetospheric signatures

International Nuclear Information System (INIS)

Sibeck, D.G.; Baumjohann, W.

1989-01-01

Contrary to the prevailing popular view, we find some transient ground events with bipolar north-south signatures are related to variations in solar wind dynamic pressure and not necessarily to magnetic merging. We present simultaneous solar wind plasma observations for two previously reported transient ground events observed at dayside auroral latitudes. During the first event, originally reported by Lanzerotti et al. [1987], conjugate ground magnetometers recorded north-south magetic field deflections in the east-west and vertical directions. The second event was reported by Todd et al. [1986], we noted ground rader observations indicating strong northward then southward ionospheric flows. The events were associated with the postulated signatures of patchy, sporadic, merging of magnetosheath and magnetospheric magnetic field lines at the dayside magnetospause, known as flux transfer events. Conversely, we demonstrate that the event reported by Lanzerotti et al. was accompanied by a sharp increase in solar wind dynamic pressure, a magnetospheric compression, and a consequent ringing of the magnetospheric magnetic field. The event reported by Todd et al. was associated with a brief but sharp increase in the solar wind dynamic pressure. copyright American Geophysical Union 1989

The effects of pressure, temperature, and pore water on velocities in Westerly granite. [for seismic wave propagation

Science.gov (United States)

Spencer, J. W., Jr.; Nur, A. M.

1976-01-01

A description is presented of an experimental assembly which has been developed to conduct concurrent measurements of compressional and shear wave velocities in rocks at high temperatures and confining pressures and with independent control of the pore pressure. The apparatus was used in studies of the joint effects of temperature, external confining pressure, and internal pore water on sonic velocities in Westerly granite. It was found that at a given temperature, confining pressure has a larger accelerating effect on compressional waves in dry rock, whereas at a given confining pressure, temperature has a larger retarding effect on shear waves.

5 CFR 532.205 - The use of Federal, State, and local minimum wage requirements in determining prevailing rates.

Science.gov (United States)

2010-01-01

... minimum wage requirements in determining prevailing rates. 532.205 Section 532.205 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PREVAILING RATE SYSTEMS Prevailing Rate Determinations § 532.205 The use of Federal, State, and local minimum wage requirements in determining prevailing...

78 FR 60182 - Prevailing Rate Systems; Definition of Broward County, Florida, to a Nonappropriated Fund Federal...

Science.gov (United States)

2013-10-01

... OFFICE OF PERSONNEL MANAGEMENT 5 CFR Part 532 RIN 3206-AM83 Prevailing Rate Systems; Definition of... wage area. The Federal Prevailing Rate Advisory Committee, the national labor-management committee... follows: PART 532--PREVAILING RATE SYSTEMS 0 1. The authority citation for part 532 continues to read as...

78 FR 29658 - Prevailing Rate Systems; Definition of Broward County, Florida, to a Nonappropriated Fund Federal...

Science.gov (United States)

2013-05-21

... OFFICE OF PERSONNEL MANAGEMENT 5 CFR Part 532 RIN 3206-AM83 Prevailing Rate Systems; Definition of... and Palm Beach Counties, FL. The Federal Prevailing Rate Advisory Committee, the national labor... 532--PREVAILING RATE SYSTEMS 0 1. The authority citation for part 532 continues to read as follows...

Climate windows for Polynesian voyaging to New Zealand and Easter Island.

Science.gov (United States)

Goodwin, Ian D; Browning, Stuart A; Anderson, Atholl J

2014-10-14

Debate about initial human migration across the immense area of East Polynesia has focused upon seafaring technology, both of navigation and canoe capabilities, while temporal variation in sailing conditions, notably through climate change, has received less attention. One model of Polynesian voyaging observes that as tradewind easterlies are currently dominant in the central Pacific, prehistoric colonization canoes voyaging eastward to and through central East Polynesia (CEP: Society, Tuamotu, Marquesas, Gambier, Southern Cook, and Austral Islands) and to Easter Island probably had a windward capacity. Similar arguments have been applied to voyaging from CEP to New Zealand against prevailing westerlies. An alternative view is that migration required reliable off-wind sailing routes. We investigate the marine climate and potential voyaging routes during the Medieval Climate Anomaly (MCA), A.D. 800-1300, when the initial colonization of CEP and New Zealand occurred. Paleoclimate data assimilation is used to reconstruct Pacific sea level pressure and wind field patterns at bidecadal resolution during the MCA. We argue here that changing wind field patterns associated with the MCA provided conditions in which voyaging to and from the most isolated East Polynesian islands, New Zealand, and Easter Island was readily possible by off-wind sailing. The intensification and poleward expansion of the Pacific subtropical anticyclone culminating in A.D. 1140-1260 opened an anomalous climate window for off-wind sailing routes to New Zealand from the Southern Austral Islands, the Southern Cook Islands, and Tonga/Fiji Islands.

Subtropical westerly jet waveguide and winter persistent heavy rainfall in south China

Science.gov (United States)

Ding, Feng; Li, Chun

2017-07-01

Using observed daily precipitation and National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis data, what induced winter large spatial persistent heavy rainfall (PHR) events in south China was examined, based on composite analyses of 30 large spatial PHR events during 1951-2015. The results showed that wave trains within North Africa-Asia (NAA) westerly jet existed in upper troposphere during these PHR processes. The wave trains shared the characteristic of a Rossby wave. The Rossby wave originated from northwest Europe, entered into the NAA jet through strong cold air advection to form convergence over the Mediterranean, and then propagated eastward along subtropical NAA jet. The Rossby wave propagated toward Southeast Asia and caused strong divergence in the upper troposphere. The strong divergence in the upper troposphere induced vertical convection and favored large spatial PHR events in south China. In addition, the enhanced India-Burma trough and subtropical high in the northwestern Pacific supplied enough water vapor transportation. This mechanism would be useful to the medium-range forecast of such winter rainfall processes over south China.

76 FR 9640 - Prevailing Rate Systems: Santa Clara, CA, Tulsa County, OK, and Angelina County, TX

Science.gov (United States)

2011-02-22

... OFFICE OF PERSONNEL MANAGEMENT 5 CFR Part 532 RIN 3206-AM22 Prevailing Rate Systems: Santa Clara... County, Texas, as an area of application to the Dallas, TX, NAF FWS wage area. The Federal Prevailing.... Accordingly, the U.S. Office of Personnel Management amends 5 CFR part 532 as follows: PART 532--PREVAILING...

Wind as a feasible alternative source for improving the deficiency of hydroelectricity in Tanzania

International Nuclear Information System (INIS)

Kainkwa, R. M.

2006-01-01

Hydroelectricity is the main source of electricity in Tanzania since about 86% of the electricity generated is from this source. During the dry season there is normally a storage of water in the dams and as such the electricity generated is below the demand. In 2004 a natural gas power plant was inaugurated to alleviate this shortage of electricity. When generating electricity from natural gas, exotic gases are emitted which pollute our environment. This source of energy also cannot regenerate itself within the human life scale. Wind is a renewable source that can be used to supplement the shortage of hydroelectricity in Tanzania. Wind speed data collected from a location with high wind energy potential shows that electricity can be generated from the wind to alleviate this shortage of hydroelectricity. Wind and rainfall data demonstrate further that the windy season, which is from July to November coincide with the dry season in which the use of wind energy in electric generation can help to fill the gap of the hydroelectricity that prevails during that season. The use of wind instead of natural gas will reduce the environmental pollution that results from extracting energy from the fossil fuel source.(Author)

Wind power development field test project at Ebetsu plant of Oji Paper Co., Ltd. Close survey on wind conditions; Oji seishi Ebetsu kojo ni okeru furyoku kaihatsu field test jigyo (fukyo seisa) hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-11-01

A survey was made on wind conditions at the Ebetsu plant of Oji Paper Co., Ltd., on the assumption that a demonstrative equipment of a wind power generation system was installed in the plant. The survey period was one year from Oct., 1998 to Sept., 1999. The observations were carried out on the average wind velocity, average wind direction, standard deviation of velocity, and the maximum instantaneous wind velocity. With a fixed point observation at 20 m above ground, and with the minimum observation time unit of 10 minutes, an average value during the 10 minutes was determined as the measurement of each category. However, the maximum instantaneous wind velocity was determined on the measurement with the minimum observation time unit of 2 seconds. The average wind velocity was 3.2 m/s, the maximum wind velocity during the period was 34 m/s, and the prevailing wind direction was SSE (25.6%), while the total occurrence probability on the wind axis with NW-SE as the main axis was 62.9%. The intensity of turbulence was 0.28 at a wind velocity of 2.0 m/s or above and was 0.25 at 4.0 m/s or above. An estimated annual operation rate of a windmill was 37-59% using the rated value of a 150 kW, 300 kW and 750 kW class windmills. (NEDO)

General aspects of meteorology and wind flow patterns at the National Medical Cyclotron site, Camperdown, NSW, Australia

International Nuclear Information System (INIS)

Clark, G.H.; Bartsch, F.J.K.

1994-06-01

As part of an assessment into the consequences of a potential accident at the National Medical Cyclotron, Camperdown, NSW., Australia, two meteorological stations were installed to monitor the winds, temperatures and atmospheric dispersion conditions. The data will be used to assess environmental impacts of the Cyclotron's operation. In spite of the relatively poor performance of the stations, the wind data indicated significant effects of local buildings and the general urban surface roughness features. The prevailing winds during the study were from the north-north-west at night and south-south-west or north-east sea breezes during the day. Atmospheric stability/dispersion categories were typical of an urban heat island location. 11 refs., 10 tabs, 6 figs

A new long instrumental serie for the Etesian winds since 1877

Science.gov (United States)

Gómez-Delgado, F. de Paula; Vega, Inmaculada; Gallego, David; Peña-Ortiz, Cristina; Ribera, Pedro; García-Herrera, Ricardo

2016-04-01

The meteorological observations found in old ships' logbooks have been recognized as a useful source of climatic information in periods and areas not covered by other sources. In the last five years several studies have employed the wind direction observations contained in logbooks to generate climatic indices of instrumental character related to large scale patterns such as the atmospheric westerly circulation in North Atlantic, the strength of the West African Monsoon or the start date of the Indian Summer Monsoon (ISM). This study is focused on the winds in the eastern Mediterranean (EM) and its relation to the subtropical climate at decadal scale. Previous studies have shown a significant link between the frequency and strength of the prevalent summer northerly winds (Etesian winds) of the EM and the strength of the ISM. This relationship had only been studied in detail for the second half of the 20th century due to the absence of long and continuous series of wind observations in the EM for previous periods. In this work, we use historical wind data contained in ship's logbooks to generate a new climatic index, the "Etesian Wind Index", which can be defined as the percentage of days with prevalent northerly wind (between 315° and 45°) in a fixed region [10°W-20°W, 32°N-36°N]. We have been able to produce an index of the Etesian winds starting in 1877 suitable to analyze its long term variability and its relation with the ISM in unprecedented detail. Our first results show that the frequency of the northerly winds in the EM was significantly larger in the first half of the studied period, mainly due to an intensification of the zonal component in the second half of the studied period. Interestingly, the comparison with analogous Etesian wind indices computed from reanalysis products (NCEP/NCAR 20th Century (V2c) and ERA20C), shows strong discrepancies among them and with our instrumental reconstruction, which could indicate a misrepresentation of the

Klondike III/Biglow Canyon Wind Integration Project; Final Environmental Impact Statement, September 2006.

Energy Technology Data Exchange (ETDEWEB)

United States. Bonneville Power Administration

2006-09-01

BPA has been asked by PPM Energy, Inc. to interconnect 300 megawatts (MW) of electricity generated from the proposed Klondike III Wind Project to the Federal Columbia River Transmission System. Orion Energy LLC has also asked BPA to interconnect 400 MW of electricity from its proposed Biglow Canyon Wind Farm, located north and east of the proposed Klondike III Wind Project. (Portland General Electric recently bought the rights to develop the proposed Biglow Canyon Wind Farm from Orion Energy, LLC.) Both wind projects received Site Certificates from the Oregon Energy Facility Siting Council on June 30, 2006. To interconnect these projects, BPA would need to build and operate a 230-kV double-circuit transmission line about 12 miles long, expand one substation and build one new substation. The wind projects would require wind turbines, substation(s), access roads, and other facilities. Two routes for the transmission line are being considered. Both begin at PPM's Klondike Schoolhouse Substation then travel north (Proposed Action) or north and westerly (Middle Alternative) to a new BPA 230-kV substation next to BPA's existing John Day 500-kV Substation. BPA is also considering a No Action Alternative in which BPA would not build the transmission line and would not interconnect the wind projects. The proposed BPA and wind projects would be located on private land, mainly used for agriculture. If BPA decides to interconnect the wind projects, construction of the BPA transmission line and substation(s) could commence as early as the winter of 2006-07. Both wind projects would operate for much of each year for at least 20 years. The proposed projects would generally create no or low impacts. Wildlife resources and local visual resources are the only resources to receive an impact rating other than ''none'' or ''low''. The low to moderate impacts to wildlife are from the expected bird and bat mortality and the cumulative

76 FR 70365 - Prevailing Rate Systems; Redefinition of the Austin, TX and Waco, TX, Appropriated Fund Federal...

Science.gov (United States)

2011-11-14

... 3206-AM50 Prevailing Rate Systems; Redefinition of the Austin, TX and Waco, TX, Appropriated Fund... the Federal Prevailing Rate Advisory Committee to best match the counties proposed for redefinition to... Prevailing Rate Advisory Committee (FPRAC), the national labor-management committee responsible for advising...

77 FR 68073 - Prevailing Rate Systems; Redefinition of the St. Louis, MO; Southern Missouri; Cleveland, OH; and...

Science.gov (United States)

2012-11-15

... 3206-AM70 Prevailing Rate Systems; Redefinition of the St. Louis, MO; Southern Missouri; Cleveland, OH... Cleveland wage area. These changes are based on recent consensus recommendations of the Federal Prevailing... proposing the changes described below. The Federal Prevailing Rate Advisory Committee (FPRAC), the national...

75 FR 39460 - Prevailing Rate Systems; Redefinition of the Chicago, IL; Fort Wayne-Marion, IN; Indianapolis, IN...

Science.gov (United States)

2010-07-09

...-AM21 Prevailing Rate Systems; Redefinition of the Chicago, IL; Fort Wayne-Marion, IN; Indianapolis, IN... wage area. These changes are based on recent consensus recommendations of the Federal Prevailing Rate... below. The Federal Prevailing Rate Advisory Committee (FPRAC), the national labor-management committee...

Estimation of the mid-century Etesians wind pattern from EURO-CORDEX models

Science.gov (United States)

Dafka, Stella; Toreti, Andrea; Luterbacher, Juerg; Zanis, Prodromos; Tyrlis, Evangelos; Xoplaki, Elena

2017-04-01

The Etesians are one of the major and most prominent wind system, prevailing over the Aegean Sea during summer and early autumn. Here, projections of changes in 30-year (2021-2050) wind speeds relative to 1971-2000, under the 8.5 and 4.5 Representative Concentration Pathways, have been produced for Etesians. Future changes in the number of Etesian days and the associated large scale dynamics are also considered. We analyze seven simulations from three EURO-CORDEX regional climate models at a 12 km grid resolution. Both scenarios indicate that in most RCMs daily wind speeds are projected to increase by 1-1.5m/s over the Aegean Sea, suggesting that the current estimate of wind power potential for Aegean Sea will be increased with the greenhouse gas forcing in the coming decades (2021-2050). Wind direction at 10-m as well as the number of Etesian days have shown to undergo minor changes. The projected changes in sea level pressure and geopotential height anomalies at 500 hPa have a large spread among the seven simulations with a disperse tendency of strengthening of the ridge over the Balkans.

78 FR 29657 - Prevailing Rate Systems; Definition of Vanderburgh County, Indiana, to a Nonappropriated Fund...

Science.gov (United States)

2013-05-21

...-AM82 Prevailing Rate Systems; Definition of Vanderburgh County, Indiana, to a Nonappropriated Fund... County, IN; and Jefferson and Pulaski Counties, MO. The Federal Prevailing Rate Advisory Committee, the... as follows: [[Page 29658

Solar wind heavy ions from energetic coronal events

International Nuclear Information System (INIS)

Bame, S.J.

1978-01-01

Ions heavier than those of He can be resolved in the solar wind with electrostatic E/q analyzers when the local thermal temperatures are low. Ordinarily this condition prevails in the low speed solar wind found between high speed streams, i.e. the interstream, IS, solar wind. Various ions of O, Si and Fe are resolved in IS heavy ion spectra. Relative ion peak intensities indicate that the O ionization state is established in the IS coronal source regions at approx. 2.1 x 10 6 K while the state of Fe is frozen in at approx. 1.5 x 10 6 K farther out. Occasionally, anomalous spectra are observed in which the usually third most prominent ion peak, O 8+ , is depressed as are the Fe peaks ranging from Fe 12+ to Fe 7+ . A prominent peak in the usual Si 8+ position of IS spectra is self-consistently shown to be Fe 16+ . These features demonstrate that the ionization states were frozen in at higher than usual coronal temperatures. The source regions of these hot heavy ion spectra are identified as energetic coronal events including flares and nonflare coronal mass ejections. 24 references

Estimation of probability of coastal flooding: A case study in the Norton Sound, Alaska

Science.gov (United States)

Kim, S.; Chapman, R. S.; Jensen, R. E.; Azleton, M. T.; Eisses, K. J.

2010-12-01

Along the Norton Sound, Alaska, coastal communities have been exposed to flooding induced by the extra-tropical storms. Lack of observation data especially with long-term variability makes it difficult to assess the probability of coastal flooding critical in planning for development and evacuation of the coastal communities. We estimated the probability of coastal flooding with the help of an existing storm surge model using ADCIRC and a wave model using WAM for the Western Alaska which includes the Norton Sound as well as the adjacent Bering Sea and Chukchi Sea. The surface pressure and winds as well as ice coverage was analyzed and put in a gridded format with 3 hour interval over the entire Alaskan Shelf by Ocean Weather Inc. (OWI) for the period between 1985 and 2009. The OWI also analyzed the surface conditions for the storm events over the 31 year time period between 1954 and 1984. The correlation between water levels recorded by NOAA tide gage and local meteorological conditions at Nome between 1992 and 2005 suggested strong local winds with prevailing Southerly components period are good proxies for high water events. We also selected heuristically the local winds with prevailing Westerly components at Shaktoolik which locates at the eastern end of the Norton Sound provided extra selection of flood events during the continuous meteorological data record between 1985 and 2009. The frequency analyses were performed using the simulated water levels and wave heights for the 56 year time period between 1954 and 2009. Different methods of estimating return periods were compared including the method according to FEMA guideline, the extreme value statistics, and fitting to the statistical distributions such as Weibull and Gumbel. The estimates are similar as expected but with a variation.

Influence of monsoonal winds on chlorophyll-α distribution in the Beibu Gulf.

Directory of Open Access Journals (Sweden)

Chunyan Shen

Full Text Available The influence of seasonal, monsoonal winds on the temporal and spatial variability of chlorophyll-a (chl-a in the Beibu Gulf is studied based on long-term satellite data of sea surface winds, chl-a concentration and sea surface temperature (SST and in-situ observations for the years from 2002 to 2014. The analysis results indicated that under northeasterly monsoonal winds, chl-a concentrations were substantially elevated in most area of the Beibu Gulf, with a high chl-a concentration (>2 mg m-3 patch extending southwestward from the coastal water of the northeastern Gulf, consistent with the winter wind pattern. Meanwhile, the spatial distribution of high chl-a concentration is correlated with low SST in the northeastern Gulf. In the southern Gulf, there was generally low chl-a, except in the coastal waters southwest of Hainan Island. Here, the upwelling cold water prevails outside the mouth of the Beibu Gulf, driven by the southwesterly monsoonal winds and the runoff from the Changhua River, as implied by low observed SST. Correlation analysis indicated the chl-a concentration was strongly modulated by wind speed (r = 0.63, p0.7, p<0.001. Integrated analysis also showed that stratification is weak and mixing is strong in winter as affected by the high wind speed, which suggests that the wind-induced mixing is a dominant mechanism for entrainment of nutrients and the spatial distribution of chl-a in winter.

On damage detection in wind turbine gearboxes using outlier analysis

Science.gov (United States)

Antoniadou, Ifigeneia; Manson, Graeme; Dervilis, Nikolaos; Staszewski, Wieslaw J.; Worden, Keith

2012-04-01

The proportion of worldwide installed wind power in power systems increases over the years as a result of the steadily growing interest in renewable energy sources. Still, the advantages offered by the use of wind power are overshadowed by the high operational and maintenance costs, resulting in the low competitiveness of wind power in the energy market. In order to reduce the costs of corrective maintenance, the application of condition monitoring to gearboxes becomes highly important, since gearboxes are among the wind turbine components with the most frequent failure observations. While condition monitoring of gearboxes in general is common practice, with various methods having been developed over the last few decades, wind turbine gearbox condition monitoring faces a major challenge: the detection of faults under the time-varying load conditions prevailing in wind turbine systems. Classical time and frequency domain methods fail to detect faults under variable load conditions, due to the temporary effect that these faults have on vibration signals. This paper uses the statistical discipline of outlier analysis for the damage detection of gearbox tooth faults. A simplified two-degree-of-freedom gearbox model considering nonlinear backlash, time-periodic mesh stiffness and static transmission error, simulates the vibration signals to be analysed. Local stiffness reduction is used for the simulation of tooth faults and statistical processes determine the existence of intermittencies. The lowest level of fault detection, the threshold value, is considered and the Mahalanobis squared-distance is calculated for the novelty detection problem.

Comparison of Artificial Neural Networks and ARIMA statistical models in simulations of target wind time series

Science.gov (United States)

Kolokythas, Kostantinos; Vasileios, Salamalikis; Athanassios, Argiriou; Kazantzidis, Andreas

2015-04-01

The wind is a result of complex interactions of numerous mechanisms taking place in small or large scales, so, the better knowledge of its behavior is essential in a variety of applications, especially in the field of power production coming from wind turbines. In the literature there is a considerable number of models, either physical or statistical ones, dealing with the problem of simulation and prediction of wind speed. Among others, Artificial Neural Networks (ANNs) are widely used for the purpose of wind forecasting and, in the great majority of cases, outperform other conventional statistical models. In this study, a number of ANNs with different architectures, which have been created and applied in a dataset of wind time series, are compared to Auto Regressive Integrated Moving Average (ARIMA) statistical models. The data consist of mean hourly wind speeds coming from a wind farm on a hilly Greek region and cover a period of one year (2013). The main goal is to evaluate the models ability to simulate successfully the wind speed at a significant point (target). Goodness-of-fit statistics are performed for the comparison of the different methods. In general, the ANN showed the best performance in the estimation of wind speed prevailing over the ARIMA models.

Statistical analysis of wind power in the region of Veracruz (Mexico)

Energy Technology Data Exchange (ETDEWEB)

Cancino-Solorzano, Yoreley [Departamento de Ing Electrica-Electronica, Instituto Tecnologico de Veracruz, Calzada Miguel A. de Quevedo 2779, 91860 Veracruz (Mexico); Xiberta-Bernat, Jorge [Departamento de Energia, Escuela Tecnica Superior de Ingenieros de Minas, Universidad de Oviedo, C/Independencia, 13, 2a Planta, 33004 Oviedo (Spain)

2009-06-15

The capacity of the Mexican electricity sector faces the challenge of satisfying the demand of the 80 GW forecast by 2016. This value supposes a steady yearly average increase of some 4.9%. The electricity sector increases for the next eight years will be mainly made up of combined cycle power plants which could be a threat to the energy supply of the country due to the fact that the country is not self-sufficient in natural gas. As an alternative wind energy resource could be a more suitable option compared with combined cycle power plants. This option is backed by market trends indicating that wind technology costs will continue to decrease in the near future as has happened in recent years. Evaluation of the eolic potential in different areas of the country must be carried out in order to achieve the best use possible of this option. This paper gives a statistical analysis of the wind characteristics in the region of Veracruz. The daily, monthly and annual wind speed values have been studied together with their prevailing direction. The data analyzed correspond to five meteorological stations and two anemometric stations located in the aforementioned area. (author)

Statistical analysis of wind power in the region of Veracruz (Mexico)

International Nuclear Information System (INIS)

Cancino-Solorzano, Yoreley; Xiberta-Bernat, Jorge

2009-01-01

The capacity of the Mexican electricity sector faces the challenge of satisfying the demand of the 80 GW forecast by 2016. This value supposes a steady yearly average increase of some 4.9%. The electricity sector increases for the next eight years will be mainly made up of combined cycle power plants which could be a threat to the energy supply of the country due to the fact that the country is not self-sufficient in natural gas. As an alternative wind energy resource could be a more suitable option compared with combined cycle power plants. This option is backed by market trends indicating that wind technology costs will continue to decrease in the near future as has happened in recent years. Evaluation of the eolic potential in different areas of the country must be carried out in order to achieve the best use possible of this option. This paper gives a statistical analysis of the wind characteristics in the region of Veracruz. The daily, monthly and annual wind speed values have been studied together with their prevailing direction. The data analyzed correspond to five meteorological stations and two anemometric stations located in the aforementioned area. (author)

Sedimentary rhythms in coastal dunes as a record of intra-annual changes in wind climate (Łeba, Poland)

Science.gov (United States)

Ludwig, J.; Lindhorst, S.; Betzler, C.; Bierstedt, S. E.; Borówka, R. K.

2017-08-01

It is shown that coastal dunes bear a so far unread archive of annual wind intensity. Active dunes at the Polish coast near Łeba consist of two genetic units: primary dunes with up to 18 m high eastward-dipping foresets, temporarily superimposed by smaller secondary dunes. Ground-penetrating radar (GPR) data reveal that the foresets of the primary dunes are bundled into alternating packages imaged as either low- or high-amplitude reflections. High-amplitude packages are composed of quartz sand with intercalated heavy-minerals layers. Low-amplitude packages lack these heavy-mineral concentrations. Dune net-progradation is towards the east, reflecting the prevalence of westerly winds. Winds blowing parallel to the dune crest winnow the lee slope, leaving layers enriched in heavy minerals. Sediment transport to the slip face of the dunes is enhanced during the winter months, whereas winnowing predominantly takes place during the spring to autumn months, when the wind field is bi-directional. As a consequence of this seasonal shift, the sedimentary record of one year comprises one low- and one high-amplitude GPR reflection interval. This sedimentary pattern is a persistent feature of the Łeba dunes and recognized to resemble a sedimentary "bar code". To overcome hiatuses in the bar code of individual dunes and dune-to-dune variations in bar-code quality, dendrochronological methods were adopted to compile a composite bar code from several dunes. The resulting data series shows annual variations in west-wind intensity at the southern Baltic coast for the time period 1987 to 2012. Proxy-based wind data are validated against instrumental based weather observations.

PREVAIL: latest electron optics results

Science.gov (United States)

Pfeiffer, Hans C.; Golladay, Steven D.; Gordon, Michael S.; Kendall, Rodney A.; Lieberman, Jon E.; Rockrohr, James D.; Stickel, Werner; Yamaguchi, Takeshi; Okamoto, Kazuya; Umemoto, Takaaki; Shimizu, Hiroyasu; Kojima, Shinichi; Hamashima, Muneki

2002-07-01

The PREVAIL electron optics subsystem developed by IBM has been installed at Nikon's facility in Kumagaya, Japan, for integration into the Nikon commercial EPL stepper. The cornerstone of the electron optics design is the Curvilinear Variable Axis Lens (CVAL) technique originally demonstrated with a proof of concept system. This paper presents the latest experimental results obtained with the electron optical subsystem at Nikon's facility. The results include micrographs illustrating proper CVAL operation through the spatial resolution achieved over the entire optical field of view. They also include data on the most critical issue of the EPL exposure approach: subfield stitching. The methodology of distortion correction will be described and both micrographs and metrology data of stitched subfields will be presented. This paper represents a progress report of the IBM/Nikon alliance activity on EPL.

78 FR 60181 - Prevailing Rate Systems; Redefinition of the Clayton-Cobb-Fulton, Georgia, Nonappropriated Fund...

Science.gov (United States)

2013-10-01

... OFFICE OF PERSONNEL MANAGEMENT 5 CFR Part 532 RIN 3206-AM84 Prevailing Rate Systems; Redefinition of the Clayton-Cobb-Fulton, Georgia, Nonappropriated Fund Federal Wage System Wage Area AGENCY: U.S... Counties). The Federal Prevailing Rate Advisory Committee, the national labor-management committee...

Ecosystem-level changes that may be expected in a changing global climate - a British Columbia perspective. [Canada - British Columbia

Energy Technology Data Exchange (ETDEWEB)

Kimmins, J.P.; Lavender, D.P. (Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Forest Science)

1992-08-01

British Columbia is a vast province encompassing a wide latitudinal and elevational range. Four of the five major classes of climate in the world are found in British Columbia, where prevailing westerly winds from the Pacific and a series of north-south mountain ranges have produced widely differing local climates. The predicted global warming may result in the migration of species and communities upslope and toward the north, but the heterogenous nature of the present landscape suggests that such migration may not be as pronounced as that likely to occur in regions of Canada with less relief. Effects of climatic warming on long-lived temperate zone trees include possible increased frost damage in early spring; reduced seed production; increased insect and disease incidence; increased damage to forests by wildfire; and, in the warmer parts of coastal British Columbia, a winter climate too warm to satisfy the chilling requirements of some perennial plants.

Wind Forced Variability in Eddy Formation, Eddy Shedding, and the Separation of the East Australian Current

Science.gov (United States)

Bull, Christopher Y. S.; Kiss, Andrew E.; Jourdain, Nicolas C.; England, Matthew H.; van Sebille, Erik

2017-12-01

The East Australian Current (EAC), like many other subtropical western boundary currents, is believed to be penetrating further poleward in recent decades. Previous observational and model studies have used steady state dynamics to relate changes in the westerly winds to changes in the separation behavior of the EAC. As yet, little work has been undertaken on the impact of forcing variability on the EAC and Tasman Sea circulation. Here using an eddy-permitting regional ocean model, we present a suite of simulations forced by the same time-mean fields, but with different atmospheric and remote ocean variability. These eddy-permitting results demonstrate the nonlinear response of the EAC to variable, nonstationary inhomogeneous forcing. These simulations show an EAC with high intrinsic variability and stochastic eddy shedding. We show that wind stress variability on time scales shorter than 56 days leads to increases in eddy shedding rates and southward eddy propagation, producing an increased transport and southward reach of the mean EAC extension. We adopt an energetics framework that shows the EAC extension changes to be coincident with an increase in offshore, upstream eddy variance (via increased barotropic instability) and increase in subsurface mean kinetic energy along the length of the EAC. The response of EAC separation to regional variable wind stress has important implications for both past and future climate change studies.

Infauna monitoring Horns Rev offshore wind farm. Annual status report 2003

International Nuclear Information System (INIS)

Bech, M.; Leonhars, S.B.; Pedersen, John

2004-05-01

ELSAM and ELTRA have established an offshore wind farm with an output of 160 MW in the waters of Horns Rev 1420 km off Blaevands Huk, which is the most westerly point of Denmark. The first phase of construction of the wind farm started in spring 2002. Before the construction activities took place, a baseline description of the benthos was conducted as a part of an environmental monitoring programme for the establishment of the Horns Rev Offshore Wind Farm. The baseline surveys for the present monitoring programme were conducted in the wind farm area on three occasions: spring 1999, spring 2001 and September 2001. In designated reference areas, surveys were conducted in spring 1999 and September 2001. The reference areas in 1999 and September 2001 were placed at two different geographical locations because the survey in September 2001 was planned to be a part of a fish monitoring programme. A comparison between the baseline study in spring 2001 and the baseline study in autumn 2001 clearly revealed that the biomass of most species increased considerably from spring to September. Despite the increase in biomass, the overall distribution of the species and their relative abundance did not change. In order to use the baseline data to investigate a possible impact after the construction of the wind farm, it was essential to arrange the monitoring programme either in spring or in September 2003, because the baseline studies were conducted in these periods. The monitoring programme was conducted in September 2003 after the wind farm had become operational, parallel with the survey on hard bottom substrates. The impacts of the wind farm on the benthic fauna (infauna) in the area were mainly expected to be due to the alteration of the local currents. As the changes in the currents are only minor, impacts on the water chemistry and on the benthic fauna resulting from hydrodynamic causes were expected to be limited or non-existent. The main objective of the present monitoring

Infauna monitoring Horns Rev offshore wind farm. Annual status report 2003

Energy Technology Data Exchange (ETDEWEB)

Bech, M.; Leonhars, S.B.; Pedersen, John

2004-05-15

ELSAM and ELTRA have established an offshore wind farm with an output of 160 MW in the waters of Horns Rev 1420 km off Blaevands Huk, which is the most westerly point of Denmark. The first phase of construction of the wind farm started in spring 2002. Before the construction activities took place, a baseline description of the benthos was conducted as a part of an environmental monitoring programme for the establishment of the Horns Rev Offshore Wind Farm. The baseline surveys for the present monitoring programme were conducted in the wind farm area on three occasions: spring 1999, spring 2001 and September 2001. In designated reference areas, surveys were conducted in spring 1999 and September 2001. The reference areas in 1999 and September 2001 were placed at two different geographical locations because the survey in September 2001 was planned to be a part of a fish monitoring programme. A comparison between the baseline study in spring 2001 and the baseline study in autumn 2001 clearly revealed that the biomass of most species increased considerably from spring to September. Despite the increase in biomass, the overall distribution of the species and their relative abundance did not change. In order to use the baseline data to investigate a possible impact after the construction of the wind farm, it was essential to arrange the monitoring programme either in spring or in September 2003, because the baseline studies were conducted in these periods. The monitoring programme was conducted in September 2003 after the wind farm had become operational, parallel with the survey on hard bottom substrates. The impacts of the wind farm on the benthic fauna (infauna) in the area were mainly expected to be due to the alteration of the local currents. As the changes in the currents are only minor, impacts on the water chemistry and on the benthic fauna resulting from hydrodynamic causes were expected to be limited or non-existent. The main objective of the present monitoring

Is the Economic Crisis Challenging the Prevailing Gender Regime?

DEFF Research Database (Denmark)

Leschke, Janine; Jepsen, Maria

2014-01-01

and analysing the corresponding position of women and men in paid and unpaid work, the paper contains an in-depth discussion of the short- and medium-term policy responses to the crisis. Our analysis shows that independent of the prevailing gender regime, scant public attention has been directed to gender...

A case for 'prevailing ecology' as premium determinant in home ...

African Journals Online (AJOL)

A case for 'prevailing ecology' as premium determinant in home-based child care ... Ewe mothers located in Dzemeni a migrant, lakeside community in Ghana. ... It builds a case from the analysis of definitions and concepts in care literature.

Formation of aeolian dunes on Anholt, Denmark since AD 1560

DEFF Research Database (Denmark)

Clemmensen, Lars B; Bjørnsen, Mette; Murray, Andrew

2007-01-01

Sand dunes on the island of Anholt (Denmark) in the middle of Kattegat form a relatively barren, temperate climate Aeolian system, locally termed the "Desert". The dunes have developed on top of a raised beach ridge system under the influence of dominant winds from westerly directions. They are r......Sand dunes on the island of Anholt (Denmark) in the middle of Kattegat form a relatively barren, temperate climate Aeolian system, locally termed the "Desert". The dunes have developed on top of a raised beach ridge system under the influence of dominant winds from westerly directions....... They are relatively coarse-grained with an average mean grain size of 480 µm. The last phase of aeolian activity and dune formation on Anholt started after AD 1560, when the local pine forest was removed. Historical sources report intense sand mobilization in the 17th century, and new optically stimulated...... in the beginning of the 20th century probably records a temporary decrease in storminess. Ground-penetrating radar mapping of the internal structures in two dunes in the western part of the Desert (a parabolic dune and a linear dune) indicates the importance of north-westerly (storm) winds during dune formation...

Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Status report 2001

International Nuclear Information System (INIS)

Leonhard, S.B.; Pedersen, John

2002-08-01

A baseline description of the benthos was carried out in spring and autumn 2001 prior to the construction of an offshore wind farm at Horns Rev, situated approximately 15 km off Blaevands Huk, which is Denmark's most westerly point. The surveys have been conducted as part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines set up by the Danish Energy Agency for offshore wind farms. Because no environmental criteria existed for benthic communities in connection with the construction activities, no power analysis was made prior to the design of the monitoring programme. The monitoring programme established for the benthic infauna is thus somewhat limited and only major changes in the community structure are expected to be detectable. The baseline description for the benthic infauna can also be used for comparison of the stomach contents of fish in a comparative programme. A newly defined reference area may be introduced for the fish programme why sampling in this area was carried out in the autumn 2001. Samples were recovered at a total of 18 stations at 6 wind turbine locations in the wind farm area in June 2001 and at a total of 9 stations at 3 wind turbine locations in September 2001. In September additional sampling was carried out at 5 stations in a designated reference area. At the wind turbine locations sampling was carried out at 3 stations located 5, 25 and 100 m from the edge of the planned scour protection. Samples were analysed for sediment characteristics and for benthic infauna. Only the benthos relating to the macrofauna was investigated during the surveys. (au)

Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Status report 2001

Energy Technology Data Exchange (ETDEWEB)

Leonhard, S B; Pedersen, John

2002-08-15

A baseline description of the benthos was carried out in spring and autumn 2001 prior to the construction of an offshore wind farm at Horns Rev, situated approximately 15 km off Blaevands Huk, which is Denmark's most westerly point. The surveys have been conducted as part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines set up by the Danish Energy Agency for offshore wind farms. Because no environmental criteria existed for benthic communities in connection with the construction activities, no power analysis was made prior to the design of the monitoring programme. The monitoring programme established for the benthic infauna is thus somewhat limited and only major changes in the community structure are expected to be detectable. The baseline description for the benthic infauna can also be used for comparison of the stomach contents of fish in a comparative programme. A newly defined reference area may be introduced for the fish programme why sampling in this area was carried out in the autumn 2001. Samples were recovered at a total of 18 stations at 6 wind turbine locations in the wind farm area in June 2001 and at a total of 9 stations at 3 wind turbine locations in September 2001. In September additional sampling was carried out at 5 stations in a designated reference area. At the wind turbine locations sampling was carried out at 3 stations located 5, 25 and 100 m from the edge of the planned scour protection. Samples were analysed for sediment characteristics and for benthic infauna. Only the benthos relating to the macrofauna was investigated during the surveys. (au)

Horns Rev offshore wind farm. Introducing hard bottom substrate sea bottom and marine biology. Status report 2001

Energy Technology Data Exchange (ETDEWEB)

Leonhard, S.B.; Pedersen, John

2002-08-15

A baseline description of the benthos was carried out in spring and autumn 2001 prior to the construction of an offshore wind farm at Horns Rev, situated approximately 15 km off Blaevands Huk, which is Denmark's most westerly point. The surveys have been conducted as part of an environmental monitoring programme for the introduction of hard bottom substrates in the North Sea. The establishment of a monitoring programme is required according to some environmental guidelines set up by the Danish Energy Agency for offshore wind farms. Because no environmental criteria existed for benthic communities in connection with the construction activities, no power analysis was made prior to the design of the monitoring programme. The monitoring programme established for the benthic infauna is thus somewhat limited and only major changes in the community structure are expected to be detectable. The baseline description for the benthic infauna can also be used for comparison of the stomach contents of fish in a comparative programme. A newly defined reference area may be introduced for the fish programme why sampling in this area was carried out in the autumn 2001. Samples were recovered at a total of 18 stations at 6 wind turbine locations in the wind farm area in June 2001 and at a total of 9 stations at 3 wind turbine locations in September 2001. In September additional sampling was carried out at 5 stations in a designated reference area. At the wind turbine locations sampling was carried out at 3 stations located 5, 25 and 100 m from the edge of the planned scour protection. Samples were analysed for sediment characteristics and for benthic infauna. Only the benthos relating to the macrofauna was investigated during the surveys. (au)

Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations

Directory of Open Access Journals (Sweden)

C. J. Farrugia

2005-06-01

Full Text Available The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999 allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time at a radial distance of 24 to 30 RE (Earth radii. During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left- and right-hand polarized electromagnetic ion cyclotron (EIC waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (= became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the low latitude boundary layer (LLBL and duskside magnetosphere occurred under such inflated conditions that the magnetospheric magnetic pressure was insufficient to maintain pressure balance. In these crossings, the inner edge of

Characteristic features of winter precipitation and its variability over ...

Indian Academy of Sciences (India)

2World Meteorological Organization, Geneva, Switzerland. 3National Atmospheric Research Laboratory, Tirupati, India. ∗ .... of easterly trade and subtropical westerly winds move southwards, and over most of Asia, the winds .... the World Meteorological Organization (WMO) has adopted 30 years as the period for climato-.

Indian Monsoon Low-Pressure Systems Feed Up-and-Over Moisture Transport to the Southwestern Tibetan Plateau

Science.gov (United States)

Dong, Wenhao; Lin, Yanluan; Wright, Jonathon S.; Xie, Yuanyu; Xu, Fanghua; Xu, Wenqing; Wang, Yan

2017-11-01

As an integral part of the South Asian summer monsoon system, monsoon low-pressure systems (LPSs) bring large amounts of precipitation to agrarian north and central India during their passage across the subcontinent. In this study, we investigate the role of LPSs in supplying moisture from north and central India to the southwestern Tibetan Plateau (SWTP) and quantify the contribution of these systems to summer rainfall over the SWTP. The results show that more than 60% of total summer rainfall over the SWTP is related to LPS occurrence. LPSs are associated with a 15% rise in average daily rainfall and a 10% rise in rainy days over the SWTP. This relationship is maintained primarily through up-and-over transport, in which convectively lifted moisture over the Indian subcontinent is swept over the SWTP by southwesterly winds in the middle troposphere. LPSs play two roles in supplying up-and-over moisture transport. First, these systems elevate large amounts of water vapor and condensed water to the midtroposphere. Second, the circulations associated with LPSs interact with the background westerlies to induce southwesterly flow in the midtroposphere, transporting elevated moisture and condensate over the Himalayan Mountains. Our findings indicate that LPSs are influential in extending the northern boundary of the South Asian monsoon system across the Himalayas into the interior of the SWTP. The strength of this connection depends on both LPS characteristics and the configuration of the midtropospheric circulation, particularly the prevailing westerlies upstream of the SWTP.

Potencial eólico na direção predominante do vento no Nordeste brasileiro Wind energy potential for the prevailing direction in Northeast Brazil

Directory of Open Access Journals (Sweden)

Bernardo B. da Silva

2002-12-01

Full Text Available Neste trabalho, foram utilizados dados horários de velocidade e direção do vento, provenientes de registros de anemógrafo Universal Fuess, a 10 m de altura, de 77 estações climatológicas pertencentes ao Instituto Nacional de Meteorologia (INMET, no período de janeiro de 1977 a dezembro de 1981. O objetivo da pesquisa foi a determinação da potência eólica média horária da direção predominante do vento em todas as estações selecionadas. Para tanto, identificou-se a direção predominante do vento de cada localidade e se estimaram os parâmetros da distribuição de Weibull, através dos quais se calculou a potência eólica média horária. Em função dos resultados apresentados neste trabalho, constatou-se que a direção predominante do vento no Nordeste do Brasil é de Leste, com flutuações para Sudeste e Nordeste. O ajuste do Método dos Momentos evidenciou-se melhor que o dos Mínimos Quadrados. Os Estados do Maranhão e Rio Grande do Norte apresentaram, respectivamente, o menor e maior potencial eólico. As estações de Alto Parnaíba, MA, e Acaraú, CE, apresentaram, mensalmente, a menor (0,022 W m-2 e a maior (138,302 W m-2 potência eólica, respectivamente.Hourly mean data of wind speed and direction, measured with a Fuess anemograph at 10 m height, were used in this study. These data were collected from January 1977 to December 1981 at 77 weather stations located in the Northeast of Brazil. The main objective of the study was to determine the wind energy potential for the predominant wind direction of selected stations; therefore, the identification of the relative frequency related to the hourly mean wind speed of the predominant direction was carried out. Then, the parameters, of a Weibull distribution related to the hourly mean wind speed of the predominant direction at each station were estimated by Moments and Graphical methods. The results show that the predominant wind direction in Northeast as a whole is

Spatial Distribution of Stable Isotopes of Precipitation in Kumamoto, Japan

Energy Technology Data Exchange (ETDEWEB)

Anoue, M. T.; Shimada, J. [Graduate School of Science and Technology, Kumamoto University (Japan); Ichiyanagi, K. [Graduate School of Science and Technology, Kumamoto University and Japan Agency for Marine-Earth Science and Technology (Japan)

2013-07-15

To understand the spatial distribution of stable isotopic compositions in precipitation, precipitation samples were collected every two weeks from november 2009 to december 2010 at 6 points in Kumamoto, Japan. The {delta}{sup 18}O and {delta}{sup 2}H of precipitation samples were measured by isotope ratio mass spectrometry (Delta-S) with CO{sub 2}/H2{sub O} equivalent method for {delta}{sup 18}O and the chromium reduction method for {delta}2H. The range of {delta}{sup 18}O and d-excess (= {delta}{sup 2}H - 8 {delta}{sup 18}O) in precipitation is from -13.4 per mille to -3.5 per mille and from 2.6 per mille to 35.6 per mille , respectively. Seasonal variability of {delta}{sup 18}O (d-excess) in precipitation was low (high) in winter and high (low) in summer. The seasonal wind of this study area was dominated by south-westerly in summer (from June to August) and north-westerly in winter (from December to February). These wind regimes indicate seasonal variabilities of the water vapour pathway from the origin. In this paper the trend of inland effect to the {delta}{sup 18}O for both south-westerly and north-westerly are also considered. As a result, significant correlation between distances from the coastal line at south-westerly or north-westerly and {delta}{sup 18}O in precipitation was recognized, particularly from 18 February to 7 March and from 29 September to 19 October in 2010 (statistically significant with 5% level). Furthermore, in order to evaluate the course of precipitation, the column total of water vapour flux was considered in the whole period by using JRA-25 and JCDAS. It is interesting that the inland effect corresponded to the column total of water vapour flux at south-westerly (north-westerly). Hence, it is conceivable that the spatial distribution of {delta}{sup 18}O in precipitation was controlled by a column total of water vapour flux in this area. (author)

Study on the impact of sudden stratosphere warming in the upper mesosphere-lower thermosphere regions using satellite and HF radar - [Article

CSIR Research Space (South Africa)

Mbatha, N

2010-01-01

Full Text Available . The mean zonal wind (from SANAE HF radar) at the MLT shows reversal in approximately 7 days before the reversal at 10 hPa (from NCEP). This indicates that there was a downwards propagation of circulation disturbance. Westerly zonal winds dominate the winter...

FY 1998 Report on development of large-scale wind power generation systems. Part 1. Operational research on large-scale wind power generation systems; 1998 nendo ogata furyoku hatsuden system kaihatsu seika hokokusho. 1. Ogata furyoku hatsuden system no unten kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

The research and development project is implemented for large-scale wind power generation systems, and the FY 1998 results are reported. In the FY 1998, a slip property variable generator is actually mounted on the wind power generator, to conduct various types of demonstration tests. The reliability validation tests include microstructure examinations, fatigue tests and fatigue strength tests to predict residual strength in the blade. It is confirmed that the blade has a sufficient residual strength. The performance validation tests include continuous measurement of power outputs and wind velocities, and analysis of the output fluctuations. The power output performance during winter when the west wind prevails is higher than designed. In the tests for evaluating the characteristics of the system on which a slip property variable generator is mounted, the output smoothing effect is confirmed in a range beyond the rated output. The wind power generation system is continuously operated, to accumulate the operational data for, e.g., capacity factor, operating time rate, and system failure status. The FY 1998 results are 920,000kWh as the output and 21% as capacity factor. The other items investigate include aerodynamic noise reduction countermeasures, fatigue life of the wind turbine blades, economics of wind power generation, and dismantling and reuse of the wind turbines. (NEDO)

Glacial History of Southernmost South America and Implications for Movement of the Westerlies and Antarctic Frontal Zone

Science.gov (United States)

Kaplan, M. R.; Fogwill, C. J.; Hulton, N. R.; Sugden, D. E.; Peter, K. W.

2004-12-01

The ~1 Myr glacial geologic record in southern South American is one of the few available terrestrial paleoclimate proxies at orbital and suborbital time scales in the middle latitudes of the Southern Hemisphere. Presently, southernmost Patagonia lies about 3\\deg north of the Antarctic frontal zone and within the middle latitude westerlies and the climate is controlled by the surrounding maritime conditions. Thus, the long-term glacial record provides insight into the history of climatic boundaries over the middle and high latitude southern ocean, including the upwind SE Pacific Ocean, tectonic-glacial evolution of the Andes, and global climate. To date, cosmogenic nuclide and 14C dating have focused on glacial fluctuations between 51 and 53\\deg S (Torres del Paine to northern Tierra del Fuego) during the last glacial cycle, including the late glacial period. At least 4 advances occurred between ca. 25 and 17 ka, with the maximum expansion of ice ca. 25-24 ka. Major deglaciation commenced after ca. 17.5 ka, which was interrupted by a major glacial-climate event ca. 14-12 ka. Modelling experiments suggest that the ice mass needed to form the glacial maximum moraines required about a 6\\deg cooling and a slight drying relative to the present. Such a fundamental temperature reduction, despite high summer isolation, strongly suggests northward movement of the westerlies and the polar front on millennial timescales. The Patagonian record also indicates that on orbital timescales equatorward movement of climate boundaries and glacial growth was in phase with major Northern Hemisphere ice volume change, despite high local summer insolation. At suborbital timescales, the picture is more complex. While major facets of the last glacial maximum appear to be in phase between the hemispheres, at least some late glacial events may be in step with Antarctic climate change. Present and future research will further constrain the timing of glacial events over the last 1 Myr and

Large-Scale Influences on the Genesis of Tropical Cyclone Karl (2010)

Science.gov (United States)

Griffin, K.; Bosart, L. F.

2012-12-01

The events leading up to the genesis of Tropical Cyclone (TC) Karl (2010) provides a unique opportunity to examine the continuing problem of understanding tropical cyclogenesis. The PRE-Depression Investigation of Cloud-systems in the Tropics (PREDICT) field campaign allowed for detailed investigation of the tropical disturbance that served as the precursor to TC Karl as it progressed westward through the Caribbean Sea. The purpose of this presentation is to examine the evolution of the pre-Karl disturbance using both common synoptic-scale analyses as well as statistically-based equatorial wave analyses, focusing on where these analyses complement and enhance each other. One of the major factors in the initial spin-up of the pre-Karl tropical disturbance is a surge of southerly and westerly winds from northern South America on 8-10 September 2010. As the surge entered the Caribbean on 9 September, it aided in the formation of a nearly closed earth-relative cyclonic circulation near the southern Leeward Islands. This circulation weakened late on 10 September and remained weak through 13 September before increased organization led to TC genesis on 14 September. This southerly wind surge can be traced to a well-defined surge of anomalously cold air and enhanced southerly winds originating in the lee of the Argentinian Andes over a week prior. While the temperature anomalies wash out prior to reaching the equator, anomalous low-level winds progress into Colombia and Venezuela, where topography aids in turning the southerly winds eastward. An investigation of the pre-Karl environment utilizing wavenumber-frequency filtering techniques also suggests that the initial spin-up of pre-Karl can be associated with the active phase of a convectively coupled Kelvin wave (CCKW). The observed formation of the nearly closed cyclonic circulation on 10 September is well timed with the passage of anomalous westerly winds along and behind the convectively active phase of a CCKW. These

Effects of offshore wind farms on marine wildlife-a generalized impact assessment

DEFF Research Database (Denmark)

Bergstrom, L.; Kautsky, L.; Malm, T.

2014-01-01

study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range......, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating...... that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity...

Embriogénesis somática de Citrus macrophylla Wester con el empleo del Pectimorf® y análogos de brasinoesteroides

OpenAIRE

Lourdes Bao Fundora; Reina M. Hernández Ortiz; Esther Diosdado Salces; María Isabel Román; Clara González Arencibia; Alejandro Rojas Álvarez; Alianny Rodríguez Valdés

2013-01-01

Título en ingles: Somatic embryogenesis of Citrus macrophylla Wester using Pectimorf® and analogues of brassinosteroids Resumen Los cítricos son frutales muy utilizados como patrones de injerto. Para incrementar la cantidad de estos cultivos en las plantaciones citrícolas, se pueden usar técnicas de propagación in vitro como la embriogénesis somática, que requiere medios de cultivos artificiales y fitohormonas. Debido a los altos costos de las fitohormonas, una alternativa cubana es e...

76 FR 14679 - Prevailing Wage Rates for Construction Occupations on Guam for Purposes of the H-2B Temporary...

Science.gov (United States)

2011-03-17

...)(v)(E) and (F). If the prevailing wage rate is too low, available U.S. workers may be dissuaded from... Docket No. USCIS-2010-0006] RIN 1615-ZA98 Prevailing Wage Rates for Construction Occupations on Guam for... the public on the system that the Governor of Guam is using to determine prevailing wage rates for...

After an initial, localized decline in rock lobster Jasus lalandii growth ...

African Journals Online (AJOL)

spamer

Pacific Ocean. In the southern Benguela, the most obvious signature of this ENSO was the reduced fre- quency and intensity of southerly, upwelling-inducing winds, with a concomitant increase in westerly winds. This study attempts to relate the reduction in lobster growth and productivity to environmental factors which.

Assessment of ENSEMBLES regional climate models for the representation of monthly wind characteristics in the Aegean Sea (Greece): Mean and extremes analysis

Science.gov (United States)

Anagnostopoulou, Christina; Tolika, Konstantia; Tegoulias, Ioannis; Velikou, Kondylia; Vagenas, Christos

2013-04-01

The main scope of the present study is the assessment of the ability of three of the most updated regional climate models, developed under the frame of the European research project ENSEMBLES (http://www.ensembles-eu.org/), to simulate the wind characteristics in the Aegean Sea in Greece. The examined models are KNMI-RACMO2, MPI-MREMO, and ICTP - RegCM3. They all have the same spatial resolution (25x25km) and for their future projections they are using the A1B SRES emission scenarios. Their simulated wind data (speed and direction) were compared with observational data from several stations over the domain of study for a time period of 25 years, from 1980 to 2004 on a monthly basis. The primer data were available every three or six hours from which we computed the mean daily wind speed and the prevailing daily wind direction. It should be mentioned, that the comparison was made for the grid point that was the closest to each station over land. Moreover, the extreme speed values were also calculated both for the observational and the simulated data, in order to assess the ability of the models in capturing the most intense wind conditions. The first results of the study showed that the prevailing winds during the winter and spring months have a north - northeastern or a south - south western direction in most parts of the Aegean sea. The models under examination seem to capture quite satisfactorily this pattern as well as the general characteristics of the winds in this area. During summer, winds in the Aegean Sea have mainly north direction and the models have quite good agreement both in simulating this direction and the wind speed. Concerning the extreme wind speed (percentiles) it was found that for the stations in the northern Aegean all the models overestimate the extreme wind indices. For the eastern parts of the Aegean the KNMI and the MPI model underestimate the extreme wind speeds while on the other hand the ICTP model overestimates them. Finally for the

Wind-power installation on the Guetsch in Switzerland; Windkraftanlage Guetsch, EW Ursern, Andermatt UR

Energy Technology Data Exchange (ETDEWEB)

Russi, M.

2006-07-01

This comprehensive final report for the Swiss Federal Office of Energy (SFOE) takes a look at the 800 kW wind turbine installed in 2001/2002 by the Ursern electricity utility near Andermatt, Switzerland, at a height of 2350 meters above sea level. The original prototype wind turbine contained various components from Swiss industry, such as the generator and the inverter. Because of difficulties (cracks in rotor blades, bankruptcy of the manufacturer, etc.) this installation was replaced by an Enercon 600-kW-wind turbine in 2004. Characteristic features of this turbine, such as is its adaptation for use under turbulent wind conditions at cold locations, are discussed. The results obtained in 2005 made it obvious that the utilisation of wind energy in alpine regions is possible and that the extreme conditions at this location do not significantly affect the efficient and safe operation of such an installation. Together with the presence of a meteorological station in the vicinity, optimal operating conditions prevail at this site for further research projects in connection with icing-up of turbine blades and wind energy. The report describes the installation and de-installation of the first turbine and the installation of the present one. Initial experience gained with the installation and its certification by the 'Naturemade' eco-power programme is discussed, as is future expansion at the site.

Gamma rays from active regions in the galaxy: the possible contribution of stellar winds

International Nuclear Information System (INIS)

Cesarsky, C.J.; Montmerle, Thierry.

1982-08-01

Massive stars release a considerable amount of mechanical energy in the form of strong stellar winds. A fraction of this energy may be transferred to relativistic cosmic rays by diffusive shock acceleration at the wind boundary, and/or in the expanding, turbulent wind itself. Massive stars are most frequently found in OB associations, surrounded by H II regions lying at the edge of dense molecular clouds. The interaction of the freshly accelerated particles with matter gives rise to #betta#-ray emission. In this paper, we first briefly review the current knowledge on the energetics of strong stellar winds from O and Wolf-Rayet stars, as well as from T Tauri stars. Taking into account the finite lifetime of these stars, we then proceed to show that stellar winds dominate the energetics of OB associations during the first 4 to 6 million years, after which supernovae take over. In the solar neighborhood, the star formation rate is constant, and a steady-state situation prevails, in which the supernova contribution is found to be dominant. A small, but meaningful fraction of the CO S-B #betta#-ray sources may be fueled by WR and O stellar winds in OB associations, while the power released by T Tauri stars alone is perhaps insufficient to account for the #betta#-ray emission of nearby dark clouds. Finally, we discuss some controversial aspects of the physics of particle acceleration by stellar winds

Long-period variations of wind parameters in the mesopause region and the solar cycle dependence

International Nuclear Information System (INIS)

Greisiger, K.M.; Schminder, R.; Kuerschner, D.

1987-01-01

A solar dependence of wind parameters below 100 km was found by Sprenger and Schminder on the basis of long-term continuous ionospheric drift measurements. For winter they obtained for the prevailing wind a positive correlation with solar activity and for the amplitude of the semi-diurnal tidal wind a negative correlation. However, after the years 1973-1974 we found a significant negative correlation with solar activity with an indication of a new change after 1983. We conclude that this long-term behaviour points rather to a climatic variation with an internal atmospheric cause than to a direct solar control. Recent satellite data of the solar u.v. radiation and the upper stratospheric ozone have shown that the possible variation of the thermal tidal excitation during the solar cycle amounts to only a few per cent. This is, therefore, insufficient to account for the 40-70% variation of the tidal amplitudes. Some other possibilities of explaining this result are discussed. (author)

Impact of the Clean Development Mechanism on wind energy investments in Turkey

Energy Technology Data Exchange (ETDEWEB)

Tunc, Murat; Pak, Ruhan [Yeditepe Univ., Istanbul (Turkey). Systems Engineering Dept.

2012-12-01

As carbon trading continues to be implemented on both a national and an international scale, it is becoming an important factor in renewable energy investment decisions. Turkey, with continuous growth of carbon dioxide emission and energy consumption since 2001, ratified the Kyoto Protocol in 2009 and began registration of projects with greenhouse gas reductions in 2010. In light of these developments, wind energy resources with a potential of 48,000 MW are among the most efficient and effective solutions for clean and sustainable energy in Turkey. The aim of our study is to reveal the importance of the Clean Development Mechanism (CDM) of the Kyoto Protocol on wind energy investment decisions. A broad review of wind energy in Turkey is given, and then, a comprehensive feasibility study of a wind energy firm with a valuation model including Certified Emission Reduction (CER) prices is applied to a case study, the Mega Metallurgy Power. With a holistic and interdisciplinary system engineering approach, results are obtained using comprehensive analysis of technology, emission, and power generation of a wind energy firm linked to a valuation model. This comprehensive model sets the investment decision-making criteria, the enterprise value comparison with total financing. Finally, a sensitivity analysis is run to show that the enterprise value is positively correlated with CER prices. Based on these results, it is concluded that if the world's largest carbon offsetting program, the CDM, prevails after 2012, CER prices will have a positive impact on wind energy firm valuations and related investment decisions. (orig.)

Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations

Directory of Open Access Journals (Sweden)

C. J. Farrugia

2005-06-01

Full Text Available The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999 allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time at a radial distance of 24 to 30 R_E (Earth radii. During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left- and right-hand polarized electromagnetic ion cyclotron (EIC waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (= became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the

The market value and impact of offshore wind on the electricity spot market: Evidence from Germany

International Nuclear Information System (INIS)

Ederer, Nikolaus

2015-01-01

Highlights: • Market value of offshore wind based on feed-in and weather data is assessed. • Merit order effect caused by wind energy is simulated for 2006–2014. • Results indicate same impact of on- and offshore wind on market price and value. • Steadier wind resource offshore imposes less variability on market price. • Characteristic of variable wind feed-in cannot be blamed for price deterioration. - Abstract: Although the expansion of offshore wind has recently increased in Germany, as in other countries, it is still forced to defend its role in long-term energy policy plans, particularly against its onshore counterpart, to secure future expansion targets and financial support. The objective of this article is to investigate the economic effects of offshore wind on the electricity spot market and thus open up another perspective that has not been part of the debate about offshore vs. onshore wind thus far. A comprehensive assessment based on a large amount of market, feed-in and weather data in Germany revealed that the market value of offshore wind is generally higher than that of onshore wind. Simulating the merit order effect on the German day-ahead electricity market for the short term and long term in the years 2006–2014 aimed to identify the reason for this observation and show whether it is also an indication of a lower impact on the electricity spot market due to a steadier wind resource prevailing offshore. Although the results suggest no difference regarding the impact on market price and value, they indeed reveal that offshore wind imposes less variability on the spot market price than onshore wind. In addition, the long-term simulation proved that the ongoing price deterioration cannot be blamed on the characteristic of variable wind production

Pollutant Concentrations in Street Canyons of Different Aspect Ratio with Avenues of Trees for Various Wind Directions

Science.gov (United States)

Gromke, Christof; Ruck, Bodo

2012-07-01

This study summarizes the effects of avenues of trees in urban street canyons on traffic pollutant dispersion. We describe various wind-tunnel experiments with different tree-avenue models in combination with variations in street-canyon aspect ratio W/ H (with W the street-canyon width and H the building height) and approaching wind direction. Compared to tree-free street canyons, in general, higher pollutant concentrations are found. Avenues of trees do not suppress canyon vortices, although the air ventilation in canyons is hindered significantly. For a perpendicular wind direction, increases in wall-average and wall-maximum concentrations at the leeward canyon wall and decreases in wall-average concentrations at the windward wall are found. For oblique and perpendicular wind directions, increases at both canyon walls are obtained. The strongest effects of avenues of trees on traffic pollutant dispersion are observed for oblique wind directions for which also the largest concentrations at the canyon walls are found. Thus, the prevailing assumption that attributes the most harmful dispersion conditions to a perpendicular wind direction does not hold for street canyons with avenues of trees. Furthermore, following dimensional analysis, an estimate of the normalized wall-maximum traffic pollutant concentration in street canyons with avenues of trees is derived.

Wind-induced flow velocity effects on nutrient concentrations at Eastern Bay of Lake Taihu, China.

Science.gov (United States)

Jalil, Abdul; Li, Yiping; Du, Wei; Wang, Jianwei; Gao, Xiaomeng; Wang, Wencai; Acharya, Kumud

2017-07-01

Shallow lakes are highly sensitive to respond internal nutrient loading due to wind-induced flow velocity effects. Wind-induced flow velocity effects on nutrient suspension were investigated at a long narrow bay of large shallow Lake Taihu, the third largest freshwater lake in China. Wind-induced reverse/compensation flow and consistent flow field probabilities at vertical column of the water were measured. The probabilities between the wind field and the flow velocities provided a strong correlation at the surface (80.6%) and the bottom (65.1%) layers of water profile. Vertical flow velocity profile analysis provided the evidence of delay response time to wind field at the bottom layer of lake water. Strong wind field generated by the west (W) and west-north-west (WNW) winds produced displaced water movements in opposite directions to the prevailing flow field. An exponential correlation was observed between the current velocities of the surface and the bottom layers while considering wind speed as a control factor. A linear model was developed to correlate the wind field-induced flow velocity impacts on nutrient concentration at the surface and bottom layers. Results showed that dominant wind directions (ENE, E, and ESE) had a maximum nutrient resuspension contribution (nutrient resuspension potential) of 34.7 and 43.6% at the surface and the bottom profile layers, respectively. Total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP) average concentrations were 6.38, 1.5, and 0.03 mg/L during our field experiment at Eastern Bay of Lake Taihu. Overall, wind-induced low-to-moderate hydrodynamic disturbances contributed more in nutrient resuspension at Eastern Bay of Lake Taihu. The present study can be used to understand the linkage between wind-induced flow velocities and nutrient concentrations for shallow lakes (with uniform morphology and deep margins) water quality management and to develop further models.

Upwelling characteristics in the Gulf of Finland (Baltic Sea) as revealed by Ferrybox measurements in 2007-2013

Science.gov (United States)

Kikas, Villu; Lips, Urmas

2016-07-01

Ferrybox measurements have been carried out between Tallinn and Helsinki in the Gulf of Finland (Baltic Sea) on a regular basis since 1997. The system measures autonomously water temperature, salinity, chlorophyll a fluorescence and turbidity and takes water samples for further analyses at a predefined time interval. We aimed to show how the Ferrybox technology could be used to study the coastal upwelling events in the Gulf of Finland. Based on the introduced upwelling index and related criteria, 33 coastal upwelling events were identified in May-September 2007-2013. The number of events, as well as the frequency of their occurrence and intensity expressed as a sum of daily average temperature deviations in the 20 km wide coastal area, were almost equal near the northern and southern coasts. Nevertheless, the wind impulse, which was needed to generate upwelling events of similar intensity, differed between the northern and southern coastal areas. It is suggested that the general thermohaline structure adapted to the prevailing forcing and the estuarine character of the basin weaken the upwelling created by the westerly to southwesterly (up-estuary) winds and strengthen the upwelling created by the easterly to northeasterly (down-estuary) winds. Two types of upwelling events were identified - one characterized by a strong temperature front and the other revealing gradual decrease in temperature from the open sea to the coastal area, with maximum temperature deviation close to the shore.

Potential climatic impacts and reliability of very large-scale wind farms

Directory of Open Access Journals (Sweden)

C. Wang

2010-02-01

Full Text Available Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG emission technologies such as wind energy. The widespread availability of wind power has fueled substantial interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using wind turbines to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1 °C over land installations. In contrast, surface cooling exceeding 1 °C is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate wind turbines. Additional theory and new field observations will be required for their ultimate validation. Intermittency of wind power on daily, monthly and longer time scales as computed in these simulations and inferred from meteorological observations, poses a demand for one or more options to ensure

Vets prevail online intervention reduces PTSD and depression in veterans with mild-to-moderate symptoms.

Science.gov (United States)

Hobfoll, Stevan E; Blais, Rebecca K; Stevens, Natalie R; Walt, Lisa; Gengler, Richard

2016-01-01

Despite heightened rates of depression and posttraumatic stress disorder (PTSD) among in Iraq/Afghanistan veterans, the majority of distressed veterans will not receive mental health care. Overcoming barriers to mental health services requires innovative approaches to broaden the reach of evidence-based treatment. The current study examined the efficacy and acceptability of an innovative and dynamic online cognitive-behavioral therapy intervention for PTSD and depression called Vets Prevail. A randomized clinical trial conducted between 2011 and 2013 assessed changes in PTSD and depression in veterans with mild-to-moderate distress. Veterans randomized to Vets Prevail (n = 209) were aged 34.2 ± 7.6 years, mostly male (81.3%), and nonminority (73.7%). Veterans randomized to adjustment as usual (n = 94) were aged 34.7 ± 8.9, mostly male (81.9%), and White (67.0%). Veterans completed the PTSD Checklist-Military Version and the Center for Epidemiological Studies Depression scale (10-item version) postintervention and at 12-week follow-up. Veterans in the Vets Prevail condition reported significantly greater reductions in PTSD, t(250) = 3.24, p = .001 (Mreduction = 5.51, SD = 9.63), and depression, t(252) = 4.37, p = .001 (Mreduction = 2.31, SD = 5.34), at 12-week follow-up compared with veterans in the adjustment as usual condition (PTSD Mreduction = 1.00, SD = 7.32; depression Mreduction = 0.48, SD = 4.95), with moderate effect sizes for PTSD (Cohen's d = 0.42) and depression (Cohen's d = 0.56). Exploratory analysis shows that Vets Prevail may be effective regardless of combat trauma exposure, gender, and ethnic minority status. Vets Prevail circumvents many barriers to care and effectively addresses the dire mental health needs of veterans. (c) 2015 APA, all rights reserved).

The impact of monsoon intraseasonal variability on renewable power generation in India

International Nuclear Information System (INIS)

Dunning, C M; Turner, A G; Brayshaw, D J

2015-01-01

India is increasingly investing in renewable technology to meet rising energy demands, with hydropower and other renewables comprising one-third of current installed capacity. Installed wind-power is projected to increase 5-fold by 2035 (to nearly 100GW) under the International Energy Agency's New Policies scenario. However, renewable electricity generation is dependent upon the prevailing meteorology, which is strongly influenced by monsoon variability. Prosperity and widespread electrification are increasing the demand for air conditioning, especially during the warm summer. This study uses multi-decadal observations and meteorological reanalysis data to assess the impact of intraseasonal monsoon variability on the balance of electricity supply from wind-power and temperature-related demand in India. Active monsoon phases are characterized by vigorous convection and heavy rainfall over central India. This results in lower temperatures giving lower cooling energy demand, while strong westerly winds yield high wind-power output. In contrast, monsoon breaks are characterized by suppressed precipitation, with higher temperatures and hence greater demand for cooling, and lower wind-power output across much of India. The opposing relationship between wind-power supply and cooling demand during active phases (low demand, high supply) and breaks (high demand, low supply) suggests that monsoon variability will tend to exacerbate fluctuations in the so-called demand-net-wind (i.e., electrical demand that must be supplied from non-wind sources). This study may have important implications for the design of power systems and for investment decisions in conventional schedulable generation facilities (such as coal and gas) that are used to maintain the supply/demand balance. In particular, if it is assumed (as is common) that the generated wind-power operates as a price-taker (i.e., wind farm operators always wish to sell their power, irrespective of price) then investors

The impact of monsoon intraseasonal variability on renewable power generation in India

Science.gov (United States)

Dunning, C. M.; Turner, A. G.; Brayshaw, D. J.

2015-06-01

India is increasingly investing in renewable technology to meet rising energy demands, with hydropower and other renewables comprising one-third of current installed capacity. Installed wind-power is projected to increase 5-fold by 2035 (to nearly 100GW) under the International Energy Agency's New Policies scenario. However, renewable electricity generation is dependent upon the prevailing meteorology, which is strongly influenced by monsoon variability. Prosperity and widespread electrification are increasing the demand for air conditioning, especially during the warm summer. This study uses multi-decadal observations and meteorological reanalysis data to assess the impact of intraseasonal monsoon variability on the balance of electricity supply from wind-power and temperature-related demand in India. Active monsoon phases are characterized by vigorous convection and heavy rainfall over central India. This results in lower temperatures giving lower cooling energy demand, while strong westerly winds yield high wind-power output. In contrast, monsoon breaks are characterized by suppressed precipitation, with higher temperatures and hence greater demand for cooling, and lower wind-power output across much of India. The opposing relationship between wind-power supply and cooling demand during active phases (low demand, high supply) and breaks (high demand, low supply) suggests that monsoon variability will tend to exacerbate fluctuations in the so-called demand-net-wind (i.e., electrical demand that must be supplied from non-wind sources). This study may have important implications for the design of power systems and for investment decisions in conventional schedulable generation facilities (such as coal and gas) that are used to maintain the supply/demand balance. In particular, if it is assumed (as is common) that the generated wind-power operates as a price-taker (i.e., wind farm operators always wish to sell their power, irrespective of price) then investors in

The development and calibration of a physical model to assist in optimising the hydraulic performance and design of maturation ponds.

Science.gov (United States)

Aldana, G J; Lloyd, B J; Guganesharajah, K; Bracho, N

2005-01-01

A physical and a computational fluid dynamic (CFD) model (HYDRO-3D) were developed to simulate the effects of novel maturation pond configurations, and critical environmental factors (wind speed and direction) on the hydraulic efficiency (HE) of full-scale maturation ponds. The aims of the study were to assess the reliability of the physical model and convergence with HYDRO-3D, as tools for assessing and predicting best hydraulic performance of ponds. The physical model of the open ponds was scaled to provide a similar nominal retention time (NRT) of 52 hours. Under natural conditions, with a variable prevailing westerly wind opposite to the inlet, a rhodamine tracer study on the full-scale prototype pond produced a mean hydraulic retention time (MHRT) of 18.5 hours (HE = 35.5%). Simulations of these wind conditions, but with constant wind speed and direction in both the physical model and HYDRO-3D, produced a higher MHRT of 21 hours in both models and an HE of 40.4%. In the absence of wind tracer studies in the open pond physical model revealed incomplete mixing with peak concentrations leaving the model in several hours, but an increase in MHRT to 24.5-28 hours (HE = 50.2-57.1%). Although wind blowing opposite to the inlet flow increases dispersion (mixing), it reduced hydraulic performance by 18-25%. Much higher HE values were achieved by baffles (67-74%) and three channel configurations (69-92%), compared with the original open pond configuration. Good agreement was achieved between the two models where key environmental and flow parameters can be controlled and set, but it is difficult to accurately simulate full-scale works conditions due to the unpredictability of natural hourly and daily fluctuation in these parameters.

78 FR 70599 - Federal Prevailing Rate Advisory Committee; Open Committee Meetings

Science.gov (United States)

2013-11-26

... of Personnel Management Building, 1900 E Street NW., Washington, DC. The Federal Prevailing Rate... the matters being considered and would disrupt substantially the disposition of its business... Advisory Committee, Room 5H27, 1900 E Street NW., Washington, DC 20415, (202) 606-9400. U.S. Office of...

Average thermospheric wind patterns over the polar regions, as observed by CHAMP

Directory of Open Access Journals (Sweden)

H. Lühr

2007-06-01

Full Text Available Measurements of the CHAMP accelerometer are utilized to investigate the average thermospheric wind distribution in the polar regions at altitudes around 400 km. This study puts special emphasis on the seasonal differences in the wind patterns. For this purpose 131 days centered on the June solstice of 2003 are considered. Within that period CHAMP's orbit is precessing once through all local times. The cross-track wind estimates of all 2030 passes are used to construct mean wind vectors for 918 equal-area cells. These bin averages are presented in corrected geomagnetic coordinates. Both hemispheres are considered simultaneously providing summer and winter responses for the same prevailing geophysical conditions. The period under study is characterized by high magnetic activity (Kp=4− but moderate solar flux level (F10.7=124. Our analysis reveals clear wind features in the summer (Northern Hemisphere. Over the polar cap there is a fast day-to-night flow with mean speeds surpassing 600 m/s in the dawn sector. At auroral latitudes we find strong westward zonal winds on the dawn side. On the dusk side, however, an anti-cyclonic vortex is forming. The dawn/dusk asymmetry is attributed to the combined action of Coriolis and centrifugal forces. Along the auroral oval the sunward streaming plasma causes a stagnation of the day-to-night wind. This effect is particularly clear on the dusk side. On the dawn side it is evident only from midnight to 06:00 MLT. The winter (Southern Hemisphere reveals similar wind features, but they are less well ordered. The mean day-to-night wind over the polar cap is weaker by about 35%. Otherwise, the seasonal differences are mainly confined to the dayside (06:00–18:00 MLT. In addition, the larger offset between geographic and geomagnetic pole in the south also causes hemispheric differences of the thermospheric wind distribution.

Average thermospheric wind patterns over the polar regions, as observed by CHAMP

Directory of Open Access Journals (Sweden)

H. Lühr

2007-06-01

Full Text Available Measurements of the CHAMP accelerometer are utilized to investigate the average thermospheric wind distribution in the polar regions at altitudes around 400 km. This study puts special emphasis on the seasonal differences in the wind patterns. For this purpose 131 days centered on the June solstice of 2003 are considered. Within that period CHAMP's orbit is precessing once through all local times. The cross-track wind estimates of all 2030 passes are used to construct mean wind vectors for 918 equal-area cells. These bin averages are presented in corrected geomagnetic coordinates. Both hemispheres are considered simultaneously providing summer and winter responses for the same prevailing geophysical conditions. The period under study is characterized by high magnetic activity (K_p=4− but moderate solar flux level (F10.7=124. Our analysis reveals clear wind features in the summer (Northern Hemisphere. Over the polar cap there is a fast day-to-night flow with mean speeds surpassing 600 m/s in the dawn sector. At auroral latitudes we find strong westward zonal winds on the dawn side. On the dusk side, however, an anti-cyclonic vortex is forming. The dawn/dusk asymmetry is attributed to the combined action of Coriolis and centrifugal forces. Along the auroral oval the sunward streaming plasma causes a stagnation of the day-to-night wind. This effect is particularly clear on the dusk side. On the dawn side it is evident only from midnight to 06:00 MLT. The winter (Southern Hemisphere reveals similar wind features, but they are less well ordered. The mean day-to-night wind over the polar cap is weaker by about 35%. Otherwise, the seasonal differences are mainly confined to the dayside (06:00–18:00 MLT. In addition, the larger offset between geographic and geomagnetic pole in the south also causes hemispheric differences of the thermospheric wind distribution.

Combining dispersion modelling with synoptic patterns to understand the wind-borne transport into the UK of the bluetongue disease vector.

Science.gov (United States)

Burgin, Laura; Ekström, Marie; Dessai, Suraje

2017-07-01

Bluetongue, an economically important animal disease, can be spread over long distances by carriage of insect vectors (Culicoides biting midges) on the wind. The weather conditions which influence the midge's flight are controlled by synoptic scale atmospheric circulations. A method is proposed that links wind-borne dispersion of the insects to synoptic circulation through the use of a dispersion model in combination with principal component analysis (PCA) and cluster analysis. We illustrate how to identify the main synoptic situations present during times of midge incursions into the UK from the European continent. A PCA was conducted on high-pass-filtered mean sea-level pressure data for a domain centred over north-west Europe from 2005 to 2007. A clustering algorithm applied to the PCA scores indicated the data should be divided into five classes for which averages were calculated, providing a classification of the main synoptic types present. Midge incursion events were found to mainly occur in two synoptic categories; 64.8% were associated with a pattern displaying a pressure gradient over the North Atlantic leading to moderate south-westerly flow over the UK and 17.9% of the events occurred when high pressure dominated the region leading to south-easterly or easterly winds. The winds indicated by the pressure maps generally compared well against observations from a surface station and analysis charts. This technique could be used to assess frequency and timings of incursions of virus into new areas on seasonal and decadal timescales, currently not possible with other dispersion or biological modelling methods.

Solar origins of solar wind properties during the cycle 23 solar minimum and rising phase of cycle 24

Science.gov (United States)

Luhmann, Janet G.; Petrie, Gordon; Riley, Pete

2012-01-01

The solar wind was originally envisioned using a simple dipolar corona/polar coronal hole sources picture, but modern observations and models, together with the recent unusual solar cycle minimum, have demonstrated the limitations of this picture. The solar surface fields in both polar and low-to-mid-latitude active region zones routinely produce coronal magnetic fields and related solar wind sources much more complex than a dipole. This makes low-to-mid latitude coronal holes and their associated streamer boundaries major contributors to what is observed in the ecliptic and affects the Earth. In this paper we use magnetogram-based coronal field models to describe the conditions that prevailed in the corona from the decline of cycle 23 into the rising phase of cycle 24. The results emphasize the need for adopting new views of what is ‘typical’ solar wind, even when the Sun is relatively inactive. PMID:25685422

77 FR 8926 - Federal Prevailing Rate Advisory Committee; Open Committee Meetings

Science.gov (United States)

2012-02-15

... Personnel Management Building, 1900 E Street NW., Washington, DC. The Federal Prevailing Rate Advisory... considered and would disrupt substantially the disposition of its business. Therefore, these caucuses will be... 5H27, 1900 E Street NW., Washington, DC 20415, (202) 606-9400. U.S. Office of Personnel Management...

77 FR 76304 - Federal Prevailing Rate Advisory Committee; Open Committee Meetings

Science.gov (United States)

2012-12-27

... 5A06A, U.S. Office of Personnel Management Building, 1900 E Street NW., Washington, DC. The Federal... the matters being considered and would disrupt substantially the disposition of its business... Management, Federal Prevailing Rate Advisory Committee, Room 5H27, 1900 E Street NW., Washington, DC 20415...

Observational and numerical study of the Vardaris wind regime in northern Greece

Science.gov (United States)

Koletsis, I.; Giannaros, T. M.; Lagouvardos, K.; Kotroni, V.

2016-05-01

The Axios Valley, located in central-northern Greece, is surrounded by complex topography that plays a significant role in the modification of wind flow, both in terms of speed and direction. The characteristic wind regime of this valley is Vardaris, a northwesterly wind that prevails in this region, especially during the cold period of the year. Vardaris is well known for its consistent direction and high intensity, as well as for the effective advection of cold and dry air, often resulting to significant damages in local infrastructures and agriculture. A field campaign under the name AXIOS took place during the period from November 2007 through May 2008 in order to examine this particular wind flow. The analysis of the in situ observational data, which was funded by the research program THESPIA-KRIPIS, showed that topography plays a key role in intensifying Vardaris, generating gusts that approximated 30 m s- 1 during the experimental period. The air temperature and humidity fields were also found to be significantly influenced. In addition to the observational study, an intense Vardaris episode was simulated with the Weather Research and Forecasting (WRF) model at high horizontal resolution. Results revealed that the model was able to reproduce the favorable environmental conditions that lead to Vardaris occurrence, providing a useful insight on the physical mechanisms explaining its structure.

Asian Dust particles impacts on air quality and radiative forcing over Korea

International Nuclear Information System (INIS)

Kim, Y J; Noh, Y M; Song, C H; Yoon, S C; Han, J S

2009-01-01

Asian Dust particles originated from the deserts and loess areas of the Asian continent are often transported over Korea, Japan, and the North Pacific Ocean during spring season. Major air mass pathway of Asian dust storm to Korea is from either north-western Chinese desert regions or north-eastern Chinese sandy areas. The local atmospheric environment condition in Korea is greatly impacted by Asian dust particles transported by prevailing westerly wind. Since these Asian dust particles pass through heavily populated urban and industrial areas in China before it reach Korean peninsular, their physical, chemical and optical properties vary depending on the atmospheric conditions and air mass pathway characteristics. An integrated system approach has been adopted at the Advanced Environment Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosols utilizing various in-situ and optical remote sensing methods, which include a multi-channel Raman LIDAR system, sunphotometer, satellite, and in-situ instruments. Results from recent studies on impacts of Asian dust particles on local air quality and radiative forcing over Korea are summarized here.

The North Atlantic Oscillation and sea surface temperature affect loggerhead abundance around the Strait of Gibraltar

Directory of Open Access Journals (Sweden)

José C. Báez

2011-04-01

Full Text Available The aim of this study was to explore the possible link between variations in the North Atlantic Oscillation (NAO and sea surface temperature (SST and the abundance of loggerhead turtles around the Strait of Gibraltar, using stranding data for the Andalusian coastal area as a proxy for abundance. The annual average SST (from November to October in the Gulf of Cadiz was negatively associated with the total number of loggerhead strandings each year from November 1997 to October 2006 in the Gulf of Cadiz and the Alboran Sea. The average NAO index was positively associated with the number of strandings in the Gulf of Cadiz in the following year. Prevailing westerly winds during positive NAO phases and the subsequent delayed decrease in SST may lead to turtles from the west Atlantic accumulating in the Gulf of Cadiz and unsuccessfully attempting to return. Secondary causes, such as buoyancy, cold stunning, longline fisheries, net fisheries, debilitated turtle syndrome, and trauma may also increase the number of turtle strandings.

75 FR 75706 - Federal Prevailing Rate Advisory Committee; Open Committee Meetings

Science.gov (United States)

2010-12-06

... Building, 1900 E Street, NW., Washington, DC. The Federal Prevailing Rate Advisory Committee is composed of... considered and would disrupt substantially the disposition of its business. Therefore, these caucuses will be... 5H27, 1900 E Street, NW., Washington, DC 20415, (202) 606-9400. U.S. Office of Personnel Management...

76 FR 75567 - Federal Prevailing Rate Advisory Committee; Open Committee Meetings

Science.gov (United States)

2011-12-02

..., 1900 E Street, NW., Washington, DC. The Federal Prevailing Rate Advisory Committee is composed of a... disrupt substantially the disposition of its business. Therefore, these caucuses will be closed to the... 5H27, 1900 E Street, NW., Washington, DC 20415, (202) 606-9400. U.S. Office of Personnel Management...

Identification of wind fields for wave modeling near Qatar

Science.gov (United States)

Nayak, Sashikant; Balan Sobhana, Sandeepan; Panchang, Vijay

2016-04-01

Due to the development of coastal and offshore infrastructure in and around the Arabian Gulf, a large semi-enclosed sea, knowledge of met-ocean factors like prevailing wind systems, wind generated waves, and currents etc. are of great importance. Primarily it is important to identify the wind fields that are used as forcing functions for wave and circulation models for hindcasting and forecasting purposes. The present study investigates the effects of using two sources of wind-fields on the modeling of wind-waves in the Arabian Gulf, in particular near the coastal regions of Qatar. Two wind sources are considered here, those obtained from ECMWF and those generated by us using the WRF model. The wave model SWAN was first forced with the 6 hourly ERA Interim daily winds (from ECMWF) having spatial resolution of 0.125°. For the second option, wind fields were generated by us using the mesoscale wind model (WRF) with a high spatial resolution (0.1°) at every 30 minute intervals. The simulations were carried out for a period of two months (7th October-7th December, 2015) during which measurements were available from two moored buoys (deployed and operated by the Qatar Meteorological Department), one in the north of Qatar ("Qatar North", in water depth of 58.7 m) and other in the south ("Shiraouh Island", in water depth of 16.64 m). This period included a high-sea event on 11-12th of October, recorded by the two buoys where the significant wave heights (Hs) reached as high as 2.9 m (i.e. max wave height H ~ 5.22 m) and 1.9 (max wave height H ~ 3.4 m) respectively. Model results were compared with the data for this period. The scatter index (SI) of the Hs simulated using the WRF wind fields and the observed Hs was found to be about 30% and 32% for the two buoys (total period). The observed Hs were generally reproduced but there was consistent underestimation. (Maximum 27% for the high-sea event). For the Hs obtained with ERA interim wind fields, the underestimation was

Field intercomparison of prevailing sonic anemometers

Science.gov (United States)

Mauder, Matthias; Zeeman, Matthias J.

2018-01-01

Three-dimensional sonic anemometers are the core component of eddy covariance systems, which are widely used for micrometeorological and ecological research. In order to characterize the measurement uncertainty of these instruments we present and analyse the results from a field intercomparison experiment of six commonly used sonic anemometer models from four major manufacturers. These models include Campbell CSAT3, Gill HS-50 and R3, METEK uSonic-3 Omni, R. M. Young 81000 and 81000RE. The experiment was conducted over a meadow at the TERENO/ICOS site DE-Fen in southern Germany over a period of 16 days in June of 2016 as part of the ScaleX campaign. The measurement height was 3 m for all sensors, which were separated by 9 m from each other, each on its own tripod, in order to limit contamination of the turbulence measurements by adjacent structures as much as possible. Moreover, the high-frequency data from all instruments were treated with the same post-processing algorithm. In this study, we compare the results for various turbulence statistics, which include mean horizontal wind speed, standard deviations of vertical wind velocity and sonic temperature, friction velocity, and the buoyancy flux. Quantitative measures of uncertainty, such as bias and comparability, are derived from these results. We find that biases are generally very small for all sensors and all computed variables, except for the sonic temperature measurements of the two Gill sonic anemometers (HS and R3), confirming a known transducer-temperature dependence of the sonic temperature measurement. The best overall agreement between the different instruments was found for the mean wind speed and the buoyancy flux.

Prevailing of sensitive blood driving to AIDS/HIV. Provincial Blood Bank of Sancti Spíritus. 2007-2008.

Directory of Open Access Journals (Sweden)

Martha Quesada Concepción

2011-09-01

Full Text Available Because of blood transfusions are one of the ways of transmitting the immune deficiency syndrome (AIDS/HIV; it constitutes warriness from the epidemiological point of view. A descriptive research was done with the objective of determining the prevailing of sensitive blood driving AIDS/HIV in the Provincial Blood Bank from Sancti Spíritus from January 1 st , 2007 to December 31 st, 2008. The sample was conformed by 312 donants with positive diagnosis to AIDS/HIV. Some variables were used such as prevailing, age, sex, race, home town. The scores of higher prevailing to AIDS/HIV were shown by the male sex (4,42, the 26-33 year old group (1,55; it prevailing volunteer blood driving (81,0 % , and Sancti Spíritus municipality gave more cases (27,5% .Just because sensibility to tests based on antibody, that is why it is important the constant checking of all processes that guarantee blood driving to be sired.

Prevailing Wage Regulations and School Construction Costs: Evidence from British Columbia.

Science.gov (United States)

Bilginsoy, Cihan; Philips, Peter

2000-01-01

Examines effects of prevailing wage laws on school construction costs, using final cost data from six British Columbia school districts. When controlling for factors such as construction business cycle, number of competitors, and school type, there was no significant unit cost change following the Skill Development and Fair Wage Policy Act.…

Ooishi's Observation: Viewed in the Context of Jet Stream Discovery.

Science.gov (United States)

Lewis, John M.

2003-03-01

Although aircraft encounters with strong westerly winds during World War II provided the stimulus for postwar research on the jet stream, Wasaburo Ooishi observed these winds in the 1920s. Ooishi's work is reviewed in the context of earlier work in upperair observation and postwar work on the jet stream. An effort is made to reconstruct Ooishi's path to the directorship of Japan's first upper-air observatory by reliance on historical studies and memoirs from the Central Meteorological Observatory.Archival records from Japan's Aerological Observatory have been used to document Ooishi's upperair observations. The first official report from the observatory (written in 1926 and in the auxiliary language of Esperanto) assumes a central role in the study. In this report, data are stratified by season and used to produce the mean seasonal wind profiles. The profile for winter gives the first known evidence of the persistent strong westerlies over Japan that would later become known as the jet stream.

Comparing offshore wind farm wake observed from satellite SAR and wake model results

Science.gov (United States)

Bay Hasager, Charlotte

2014-05-01

Offshore winds can be observed from satellite synthetic aperture radar (SAR). In the FP7 EERA DTOC project, the European Energy Research Alliance project on Design Tools for Offshore Wind Farm Clusters, there is focus on mid- to far-field wind farm wakes. The more wind farms are constructed nearby other wind farms, the more is the potential loss in annual energy production in all neighboring wind farms due to wind farm cluster effects. It is of course dependent upon the prevailing wind directions and wind speed levels, the distance between the wind farms, the wind turbine sizes and spacing. Some knowledge is available within wind farm arrays and in the near-field from various investigations. There are 58 offshore wind farms in the Northern European seas grid connected and in operation. Several of those are spaced near each other. There are several twin wind farms in operation including Nysted-1 and Rødsand-2 in the Baltic Sea, and Horns Rev 1 and Horns Rev 2, Egmond aan Zee and Prinses Amalia, and Thompton 1 and Thompton 2 all in the North Sea. There are ambitious plans of constructing numerous wind farms - great clusters of offshore wind farms. Current investigation of offshore wind farms includes mapping from high-resolution satellite SAR of several of the offshore wind farms in operation in the North Sea. Around 20 images with wind farm wake cases have been retrieved and processed. The data are from the Canadian RADARSAT-1/-2 satellites. These observe in microwave C-band and have been used for ocean surface wind retrieval during several years. The satellite wind maps are valid at 10 m above sea level. The wakes are identified in the raw images as darker areas downwind of the wind farms. In the SAR-based wind maps the wake deficit is found as areas of lower winds downwind of the wind farms compared to parallel undisturbed flow in the flow direction. The wind direction is clearly visible from lee effects and wind streaks in the images. The wind farm wake cases

The response of the Red Sea to a strong wind jet near the Tokar Gap in summer

KAUST Repository

Zhai, Ping

2013-01-01

[1] Remote sensing and in situ observations are used to investigate the ocean response to the Tokar Wind Jet in the Red Sea. The wind jet blows down the atmospheric pressure gradient through the Tokar Gap on the Sudanese coast, at about 19°N, during the summer monsoon season. It disturbs the prevailing along-sea (southeastward) winds with strong cross-sea (northeastward) winds that can last from days to weeks and reach amplitudes of 20-25 m/s. By comparing scatterometer winds with along-track and gridded sea level anomaly observations, it is observed that an intense dipolar eddy spins up in response to the wind jet. The eddy pair has a horizontal scale of 140 km. Maximum ocean surface velocities can reach 1 m/s and eddy currents extend more than 100 m into the water column. The eddy currents appear to cover the width of the sea, providing a pathway for rapid transport of marine organisms and other drifting material from one coast to the other. Interannual variability in the strength of the dipole is closely matched with variability in the strength of the wind jet. The dipole is observed to be quasi-stationary, although there is some evidence for slow eastward propagation in an idealized numerical model. Simulation of the dipole in an idealized high-resolution numerical model suggests that this is the result of self-advection. © 2012. American Geophysical Union. All Rights Reserved.

Variability in Global-Scale Circulations and Their Impacts on Atlantic Tropical Cyclone Activity

National Research Council Canada - National Science Library

Rosencrans, Matthew J

2006-01-01

... favorable or unfavorable for tropical cyclone formation. Favorable impacts on tropical Atlantic circulation characteristics are defined by an increase in low-level relative vorticity, a decrease in westerly vertical wind shear, and increased convection...

The role of wind in hydrochorous mangrove propagule dispersal

Directory of Open Access Journals (Sweden)

T. Van der Stocken

2013-06-01

the floating orientation of the propagules. While the dispersal path of vertically floating propagules was influenced by the strength and direction of the water currents and to a lesser extent by ambient wind conditions, the dispersal path of horizontally floating propagules was influenced by both strength and direction of the water currents and prevailing wind forces. To validate the flume results, propagules of C. tagal and R. mucronata were released during outgoing tide in a tidal creek in Gazi Bay (Kenya, followed by observation of their dispersal distance and direction, while knowing the actual dominant wind direction. In line with the flume results, this study showed that wind plays an important role in the dispersal distance of the propagules. The present study provides important mechanistic insight into the effect of wind on hydrochorous mangrove propagule dispersal, thereby yielding an essential step towards the construction and optimization of (particle-based hydrodynamic dispersal models.

Evaluate prevailing climate change on Great Lakes water levels

International Nuclear Information System (INIS)

Islam, M.

2009-01-01

'Full text:'In this paper, results of a comprehensive water mass balance modeling for the Great Lakes against prevailing and different anticipated climate change scenarios would be presented. Modeling is done in evaluating the changes in the lake storages and then changes in the lake's water level considering present condition, uncertainty and variability of climate and hydrologic conditions in the future. Inflow-outflow and consequent changes in the five Great Lake's storages are simulated for the last 30 years and then projected to evaluate the changes in the lake storages for the next 50 years. From the predicted changes in the lake storage data, water level is calculated using mass to linear conversion equation. Modeling and analysis results are expected to be helpful in understanding the possible impacts of the climate change on the Great Lakes water environment and preparing strategic plan for the sustainable management of lake's water resources. From the recent past, it is observed that there is a depleting trend in the lakes water level and hence there is a potential threat to lake's water environment and uncertainty of the availability of quality and quantity of water for the future generations, especially against prevailing and anticipated climate changes. For this reason, it is an urgent issue of understanding and quantifying the potential impacts of climate change on the Great Lake's water levels and storages. (author)

Assessing the effect of wind speed/direction changes on urban heat island intensity of Istanbul.

Science.gov (United States)

Perim Temizoz, Huriye; Unal, Yurdanur S.

2017-04-01

Assessing the effect of wind speed/direction changes on urban heat island intensity of Istanbul. Perim Temizöz, Deniz H. Diren, Cemre Yürük and Yurdanur S. Ünal Istanbul Technical University, Department of Meteorological Engineering, Maslak, Istanbul, Turkey City or metropolitan areas are significantly warmer than the outlying rural areas since the urban fabrics and artificial surfaces which have different radiative, thermal and aerodynamic features alter the surface energy balance, interact with the regional circulation and introduce anthropogenic sensible heat and moisture into the atmosphere. The temperature contrast between urban and rural areas is most prominent during nighttime since heat is absorbed by day and emitted by night. The intensity of the urban heat island (UHI) vary considerably depending on the prevailent meteorological conditions and the characteristics of the region. Even though urban areas cover a small fraction of Earth, their climate has greater impact on the world's population. Over half of the world population lives in the cities and it is expected to rise within the coming decades. Today almost one fifth of the Turkey's population resides in Istanbul with the percentage expected to increase due to the greater job opportunities compared to the other cities. Its population has been increased from 2 millions to 14 millions since 1960s. Eventually, the city has been expanded tremendously within the last half century, shifting the landscape from vegetation to built up areas. The observations of the last fifty years over Istanbul show that the UHI is most pronounced during summer season. The seasonal temperature differences between urban and suburban sites reach up to 3 K and roughly haft degree increase in UHI intensity is observed after 2000. In this study, we explore the possible range of heat load and distribution over Istanbul for different prevailing wind conditions by using the non-hydrostatic MUKLIMO3 model developed by DWD

Fukushima-derived fission nuclides monitored around Taiwan: Free tropospheric versus boundary layer transport

Science.gov (United States)

Huh, Chih-An; Hsu, Shih-Chieh; Lin, Chuan-Yao

2012-02-01

The 2011 Fukushima nuclear accident in Japan was the worst nuclear disaster following the 1986 Chernobyl accident. Fission products (nuclides) released from the Fukushima plant site since March 12, 2011 had been detected around the northern hemisphere in about two weeks and also in the southern hemisphere about one month later. We report here detailed time series of radioiodine and radiocesium isotopes monitored in a regional network around Taiwan, including one high-mountain and three ground-level sites. Our results show several pulses of emission from a sequence of accidents in the Fukushima facility, with the more volatile 131I released preferentially over 134Cs and 137Cs at the beginning. In the middle of the time series, there was a pronounced peak of radiocesium observed in northern Taiwan, with activity concentrations of 134Cs and 137Cs far exceeding that of 131I during that episode. From the first arrival time of these fission nuclides and their spatial and temporal variations at our sampling sites and elsewhere, we suggest that Fukushima-derived radioactive nuclides were transported to Taiwan and its vicinity via two pathways at different altitudes. One was transported in the free troposphere by the prevailing westerly winds around the globe; the other was transported in the planetary boundary layer by the northeast monsoon wind directly toward Taiwan.

Horns Rev offshore wind power farm. Environmental impact assessment on water quality

International Nuclear Information System (INIS)

Andersen, Per

2000-05-01

As part of an overall Environmental Impact Assessment (EIA) undertaken in connection with a planned 150 MW offshore wind farm at Horns Rev, an assessment was made of the effects the wind farm would have on the water quality in the area. This EIA study was drawn up in accordance with the guidelines laid down by the Danish Ministry of Environment and Energy in the publication 'Guidelines for the preparation of EIA studies for offshore wind farms'. Horns Rev is situated off Blaevands Huk, which is Denmark's most westerly point. It is a shallow reef with water depths between 2 and 9 metres and is primarily composed of sand, gravel and pebbles. Only local and minor changes are anticipated in connection with the currents, sediments and wave conditions during the production phase. These will occur in the immediate vicinity of the individual foundations. For these reasons, no changes are expected in the water quality. This also includes also the pelagic primary production and the occurrence of plankton in the area. Increased local copper contamination of phytoplankton and zooplankton may be expected during the production phase, as a result of the total annual discharge of 206 kg copper from the slip-rings in the wind turbines. The contamination will potentially result in a local reduction of the pelagic primary production and changes in the species composition of the plankton. The wind turbines will be sandblasted and painted once during their lifetime, as part of the routine maintenance. The sandblasting and painting will lead to a temporary spill of paint, paint waste and sand. The impacts on water quality and plankton production are unknown. It is recommended that factors such as the toxicity of the paint be investigated, and that spills and the impact of waste be reduced as much as possible. The water quality and the plankton in the wind farm area and along the cable line's passage to shore through the international protected area, will only be affected in a minor way

Change of ENSO characteristics in response to global warming

Science.gov (United States)

Sun, X.; Xia, Y.; Yan, Y.; Feng, W.; Huang, F.; Yang, X. Q.

2017-12-01

By using datasets of HadISST monthly SST from 1895 to 2014 and 600-year simulations of two CESM model experiments with/without doubling of CO2 concentration, ENSO characteristics are compared pre- and post- global warming. The main results are as follows. Due to global warming, the maximum climatological SST warming occurs in the tropical western Pacific (La Niña-like background warming) and the tropical eastern Pacific (El Niño-like background warming) for observations and model, respectively, resulting in opposite zonal SST gradient anomalies in the tropical Pacific. The La Niña-like background warming induces intense surface divergence in the tropical central Pacific, which enhances the easterly trade winds in the tropical central-western Pacific and shifts the strongest ocean-atmosphere coupling westward, correspondingly. On the contrary, the El Niño-like background warming causes westerly winds in the whole tropical Pacific and moves the strongest ocean-atmosphere coupling eastward. Under the La Niña-like background warming, ENSO tends to develop and mature in the tropical central Pacific, because the background easterly wind anomaly weakens the ENSO-induced westerly wind anomaly in the tropical western Pacific, leading to the so-called "Central Pacific ENSO (CP ENSO)". However, the so-called "Eastern Pacific ENSO (EP ENSO)" is likely formed due to increased westerly wind anomaly by the El Niño-like background warming. ENSO lifetime is significantly extended under both the El Niño-like and the La Niña-like background warmings, and especially, it can be prolonged by up to 3 months in the situation of El Niño-like background warming. The prolonged El Nino lifetime mainly applies to extreme El Niño events, which is caused by earlier outbreak of the westerly wind bursts, shallower climatological thermocline depth and weaker "discharge" rate of the ENSO warm signal in response to global warming. Results from both observations and the model also show that

Terral De Vicuna, a Foehnlike Wind in Semiarid Northern Chile: Meteorological Aspects and Implications for the Fulfillment of Chill Requirements in Deciduous Fruit Trees

Science.gov (United States)

Montes, Carlo; Rutllant, Jose A.; Aguirre, Anita; Bascunan-Godoy, Luisa; Julia, Cristobal

2016-01-01

The terral de Vicuña is a warm and dry wind that flows down the Elqui Valley in north-central Chile typically at dawn and early morning. Given that most terral episodes occur in austral winter when chill accumulation by deciduous fruit trees proceeds, negative effects on agriculture may be expected. During 11 (2004-14) winters a meteorological characterization of terral winds and the assessment of their impact on chill accumulation, by the modified Utah Model and the Dynamic Model, were performed. Within this period, 67 terral days (TD) were identified as those in which nighttime to early morning wind direction and speed, air temperature, and relative humidity reached defined thresholds on an hourly basis (terral hours). Most frequent TD featured 6-9 consecutive terral hours; duration is considered here as a proxy for their intensity. Synoptic-scale meteorological analysis shows that 65% of moderate and strong terral events develop as a cold, migratory anticyclone drifts poleward of the study area, coinciding with the onset of a midtropospheric ridge over central Chile, bringing southwest winds on top of the Andes (approximately 500-hPa level). The remaining 35% are either associated with 500-hPa easterlies (foehn like), with prefrontal conditions ahead of a trough driving northwest 500-hPa winds, or with transitional 500-hPa westerlies.Assessments of chill accumulation during TD show that, although present average and cold winter conditions do not represent a major TD hazard to local agriculture, lower chill accumulation associated with anomalously high nocturnal temperatures could be significantly more important during present and future warmer winters.

75 FR 23263 - Alta Wind I, LLC; Alta Wind II, LLC; Alta Wind III, LLC; Alta Wind IV, LLC; Alta Wind V, LLC...

Science.gov (United States)

2010-05-03

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL10-62-000] Alta Wind I, LLC; Alta Wind II, LLC; Alta Wind III, LLC; Alta Wind IV, LLC; Alta Wind V, LLC; Alta Wind VI, LLC; Alta Wind VII, LLC; Alta Wind VIII, LLC; Alta Windpower Development, LLC; TGP Development Company, LLC...

77 FR 29633 - Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC...

Science.gov (United States)

2012-05-18

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL12-68-000] Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC, Alta Wind XIII, LLC, Alta Wind XIV, LLC, Alta Wind XV, LLC, Alta Windpower Development, LLC, TGP Development Company, LLC...

Computational modelling of an operational wind turbine and validation with LIDAR

Science.gov (United States)

Creech, Angus; Fruh, Wolf-Gerrit; Clive, Peter

2010-05-01

We present a computationally efficient method to model the interaction of wind turbines with the surrounding flow, where the interaction provides information on the power generation of the turbine and the generated wake behind the turbine. The turbine representation is based on the principle of an actuator volume, whereby the energy extraction and balancing forces on the fluids are formulated as body forces which avoids the extremely high computational costs of boundary conditions and forces. Depending on the turbine information available, those forces can be derived either from published turbine performance specifications or from their rotor and blade design. This turbine representation is then coupled to a Computational Fluid Dynamics package, in this case the hr-adaptive Finite-Element code Fluidity from Imperial College, London. Here we present a simulation of an operational 950kW NEG Micon NM54 wind turbine installed in the west of Scotland. The calculated wind is compared with LIDAR measurements using a Galion LIDAR from SgurrEnergy. The computational domain extends over an area of 6km by 6km and a height of 750m, centred on the turbine. The lower boundary includes the orography of the terrain and surface roughness values representing the vegetation - some forested areas and some grassland. The boundary conditions on the sides are relaxed Dirichlet conditions, relaxed to an observed prevailing wind speed and direction. Within instrumental errors and model limitations, the overall flow field in general and the wake behind the turbine in particular, show a very high degree of agreement, demonstrating the validity and value of this approach. The computational costs of this approach are such that it is possible to extend this single-turbine example to a full wind farm, as the number of required mesh nodes is given by the domain and then increases only linearly with the number of turbines

Equivalent models of wind farms by using aggregated wind turbines and equivalent winds

International Nuclear Information System (INIS)

Fernandez, L.M.; Garcia, C.A.; Saenz, J.R.; Jurado, F.

2009-01-01

As a result of the increasing wind farms penetration on power systems, the wind farms begin to influence power system, and therefore the modeling of wind farms has become an interesting research topic. In this paper, new equivalent models of wind farms equipped with wind turbines based on squirrel-cage induction generators and doubly-fed induction generators are proposed to represent the collective behavior on large power systems simulations, instead of using a complete model of wind farms where all the wind turbines are modeled. The models proposed here are based on aggregating wind turbines into an equivalent wind turbine which receives an equivalent wind of the ones incident on the aggregated wind turbines. The equivalent wind turbine presents re-scaled power capacity and the same complete model as the individual wind turbines, which supposes the main feature of the present equivalent models. Two equivalent winds are evaluated in this work: (1) the average wind from the ones incident on the aggregated wind turbines with similar winds, and (2) an equivalent incoming wind derived from the power curve and the wind incident on each wind turbine. The effectiveness of the equivalent models to represent the collective response of the wind farm at the point of common coupling to grid is demonstrated by comparison with the wind farm response obtained from the detailed model during power system dynamic simulations, such as wind fluctuations and a grid disturbance. The present models can be used for grid integration studies of large power system with an important reduction of the model order and the computation time

78 FR 29364 - Exelon Corporation, Exelon Wind 1, LLC, Exelon Wind 2, LLC, Exelon Wind 3, LLC, Exelon Wind 4...

Science.gov (United States)

2013-05-20

...-005, QF07-55-005, QF07-56-005, QF07-257-004] Exelon Corporation, Exelon Wind 1, LLC, Exelon Wind 2, LLC, Exelon Wind 3, LLC, Exelon Wind 4, LLC, Exelon Wind 5, LLC, Exelon Wind 6, LLC, Exelon Wind 7, LLC, Exelon Wind 8, LLC, Exelon Wind 9, LLC, Exelon Wind 10, LLC, Exelon Wind 11, LLC, High Plains...

Thermal Cracking in Westerly Granite Monitored Using Direct Wave Velocity, Coda Wave Interferometry, and Acoustic Emissions

Science.gov (United States)

Griffiths, L.; Lengliné, O.; Heap, M. J.; Baud, P.; Schmittbuhl, J.

2018-03-01

To monitor both the permanent (thermal microcracking) and the nonpermanent (thermo-elastic) effects of temperature on Westerly Granite, we combine acoustic emission monitoring and ultrasonic velocity measurements at ambient pressure during three heating and cooling cycles to a maximum temperature of 450°C. For the velocity measurements we use both P wave direct traveltime and coda wave interferometry techniques, the latter being more sensitive to changes in S wave velocity. During the first cycle, we observe a high acoustic emission rate and large—and mostly permanent—apparent reductions in velocity with temperature (P wave velocity is reduced by 50% of the initial value at 450°C, and 40% upon cooling). Our measurements are indicative of extensive thermal microcracking during the first cycle, predominantly during the heating phase. During the second cycle we observe further—but reduced—microcracking, and less still during the third cycle, where the apparent decrease in velocity with temperature is near reversible (at 450°C, the P wave velocity is decreased by roughly 10% of the initial velocity). Our results, relevant for thermally dynamic environments such as geothermal reservoirs, highlight the value of performing measurements of rock properties under in situ temperature conditions.

Achievement report for fiscal 1999. Research on mesh-based estimation of natural energy for Southeast Asia as represented by Myanmar (Assessment of wind power and solar energy using numerical weather model); 1999 nendo Myanmar koku wo rei ni shita Tonan Asia ni okeru shizen energy no mesh suitei ni kansuru kenkyu seika hokokusho. Suchi kisho model ni yoru furyoku taiyo energy hyoka

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

As the first step for the introduction of wind power systems and photovoltaic power systems into developing countries in Southeast Asia etc. and for their diffusion in them for the exploitation of natural energy, a numerical weather model useable in Southeast Asia is developed to make up for the insufficiency of weather data in the region. A technique is developed, to explain which the case of Myanmar is cited, for estimating with accuracy such natural conditions as wind direction, wind velocity, and solar radiation in the past one-year period for the assessment of power to be generated using wind turbines and solar panels. The results of the observation of wind conditions indicate that wind directions are mainly northerly or westerly and that wind speeds are as week as 1-3m/s on the average. As for total solar radiation per diem in December through March, it is found that there is 17-23MJ/m{sup 2}/day, which is twice the level to be measured in Tokyo. A comparison is made between the weather observation results and a model calculation, and it is found that the latter sufficiently reproduces the actual weather conditions. Based on the values of wind conditions and solar radiation estimated in Myanmar, the amount of power to be obtained from an assumed arrangement of wind power systems and solar panels is assessed. (NEDO)

Development, construction and testing of a vertical axis 200 kW wind turbine

Energy Technology Data Exchange (ETDEWEB)

1974-12-20

It is proposed to design and develop a large vertical axis wind turbine that will generate economically 200 kilowatts of power at a wind speed of about 30 miles per hour. The scope of this proposal is to carry out studies, build, erect and test an electrical power generation plant that will feed into existing power grids. Preliminary technical studies indicate that the power of the turbine increases with the third power of the the wind speed. The rotor power loading should be as high as the prevailing winds allow; thus it would always be advisable to let the rotor run at as high an rpm as the economics will allow. For turbines up to about 100 ft in diameter, an extruded blade seems to be the best solution for economic rotor design. A 300 ft/s runaway tip speed seems to be acceptable as an rpm limit. Structurally, it is advantageous to increase the blade airfoil section to 18%. The proposed program has a very high probability of success in that each element of the total system involves a very low technical risk. The manufacturing methods rely on existing technology, and preliminary research indicates that readily available commercial materials can be used. There will be no involvement with highly stressed, fatigue-sensitive components. The total unit energy cost will be about fifty percent less for the proposed 90 ft. turbine than for the 15 ft. turbine produced for the National Research Council. 8 figs., 12 tabs.

Anchovy Engraulis capensis and sardine Sardinops sagax currently ...

African Journals Online (AJOL)

spamer

Recruitment is thought to be determined largely by ... for forecasting recruitment strength. ..... In March and April, sustained upwelling wind events ... 2 Assumes average current velocities of 10–15 cm.s–1 in a west-north-westerly direction ...

Interaction between water and wind as a driver of passive dispersal in mangroves.

Directory of Open Access Journals (Sweden)

Tom Van der Stocken

Full Text Available Although knowledge on dispersal patterns is essential for predicting long-term population dynamics, critical information on the modalities of passive dispersal and potential interactions between vectors is often missing. Here, we use mangrove propagules with a wide variety of morphologies to investigate the interaction between water and wind as a driver of passive dispersal. We imposed 16 combinations of wind and hydrodynamic conditions in a flume tank, using propagules of six important mangrove species (and genera, resulting in a set of dispersal morphologies that covers most variation present in mangrove propagules worldwide. Additionally, we discussed the broader implications of the outcome of this flume study on the potential of long distance dispersal for mangrove propagules in nature, applying a conceptual model to a natural mangrove system in Gazi Bay (Kenya. Overall, the effect of wind on dispersal depended on propagule density (g l(-1. The low-density Heritiera littoralis propagules were most affected by wind, while the high-density vertically floating propagules of Ceriops tagal and Bruguiera gymnorrhiza were least affected. Avicennia marina, and horizontally floating Rhizophora mucronata and C. tagal propagules behaved similarly. Morphological propagule traits, such as the dorsal sail of H. littoralis, explained another part of the interspecific differences. Within species, differences in dispersal velocities can be explained by differences in density and for H. littoralis also by variations in the shape of the dorsal sail. Our conceptual model illustrates that different propagule types have a different likelihood of reaching the open ocean depending on prevailing water and wind currents. Results suggest that in open water, propagule traits (density, morphology, and floating orientation appear to determine the effect of water and wind currents on dispersal dynamics. This has important implications for inter- and intraspecific

SAT-WIND project. Final report[Winds from satellites for offshore and coastal wind energy mapping and wind-indexing

Energy Technology Data Exchange (ETDEWEB)

Hasager, C.B.; Astrup, P.; Nielsen, M. (and others)

2007-04-15

The SAT-WIND project 'Winds from satellites for offshore and coastal wind energy mapping and wind-indexing' was a research project funded by STVF/DSF in the years 2003 to 2006 (Sagsnr. 2058-03-0006). The goal of the project was to verify the applicability of satellite wind maps derived from passive microwave, altimeter, scatterometer and imaging Synthetic Aperture Radar (SAR) technologies for wind energy tools for wind resources and wind-indexing. The study area was the Danish Seas including the North Sea, interior seas and the Baltic Sea. The report describes technical details on the satellite data sources including: 1) passive microwave (SSM/I, AMSR-E), 2) passive microwave polarimetric (WindSat), 3) scatterometer (ERS, QuikSCAT, Midori-2 and NSCAT), 4) altimeter (ERS, Topex, Poseidon, GFO-1, Jason-1), 5) SAR (ERS, Envisat). The SAR wind maps were treated in S-WAsP developed by Risoe National Laboratory in cooperation with GRAS A/S in the innovative project SAT-WIND-SMV (Sagsnr. 2104-05-0084) in the years 2005 and 2006 in parallel with SAT-WIND. The results from the SAT-WIND project are presented. These include ocean wind statistics, offshore wind resource estimates and comparison results for wind-indexing. (au)

SAT-WIND project. Final report[Winds from satellites for offshore and coastal wind energy mapping and wind-indexing

Energy Technology Data Exchange (ETDEWEB)

Hasager, C B; Astrup, P; Nielsen, M [and others

2007-04-15

The SAT-WIND project 'Winds from satellites for offshore and coastal wind energy mapping and wind-indexing' was a research project funded by STVF/DSF in the years 2003 to 2006 (Sagsnr. 2058-03-0006). The goal of the project was to verify the applicability of satellite wind maps derived from passive microwave, altimeter, scatterometer and imaging Synthetic Aperture Radar (SAR) technologies for wind energy tools for wind resources and wind-indexing. The study area was the Danish Seas including the North Sea, interior seas and the Baltic Sea. The report describes technical details on the satellite data sources including: 1) passive microwave (SSM/I, AMSR-E), 2) passive microwave polarimetric (WindSat), 3) scatterometer (ERS, QuikSCAT, Midori-2 and NSCAT), 4) altimeter (ERS, Topex, Poseidon, GFO-1, Jason-1), 5) SAR (ERS, Envisat). The SAR wind maps were treated in S-WAsP developed by Risoe National Laboratory in cooperation with GRAS A/S in the innovative project SAT-WIND-SMV (Sagsnr. 2104-05-0084) in the years 2005 and 2006 in parallel with SAT-WIND. The results from the SAT-WIND project are presented. These include ocean wind statistics, offshore wind resource estimates and comparison results for wind-indexing. (au)

Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

OpenAIRE

Ju Feng; Wen Zhong Shen

2015-01-01

Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distributions of wind speed and wind direction, which is based on the parameters of sector-wise Weibull distributions and interpolations between direction sectors. It is applied to the wind measurement data a...

Land-falling typhoons are controlled by the meridional oscillation of the Kuroshio Extension

Science.gov (United States)

Huang, Shihming; Oey, Lie-Yauw

2018-06-01

Low-frequency variations of typhoon paths are often attributed to changes in the North Pacific subtropical high and monsoon through influences on the steering wind. Evidence indicates however a strong imprint of the Kuroshio on the atmosphere. Here we show that the meridional oscillation of sea surface temperature (SST) front over the Kuroshio Extension east of Japan significantly correlates with the number of land-falling typhoons along East Asia from June to October, accounting for 70% of the low-frequency variance since 1980. We used observations and a simple model to show that when the SST front shifts poleward (equatorward), SST gradient south of the current and westerly tropospheric wind weaken (strengthen), steering more typhoons to veer toward (away from) the East Asian continent. Our analysis also indicates that long-term weakening of SST gradient and westerly wind appears to be concomitant with poleward shifting of the Kuroshio, attributed to global warming in some studies, and suggests the potential for more land-falling typhoons in East Asia in the coming decades.

Rapid Holocene glacier fluctuations in arctic Norway in concert with the strength and spatial pattern of the westerlies

Science.gov (United States)

Bakke, J.; Dahl, S.

2011-12-01

latitudes during the Holocene. Superimposed on the gradual increase in glacier-covered areas, the four largest glacier advances are bracketed between 7400-7000, 1400-1200, 900-700 and 300-150 years before AD 2000. In contrast to most reconstructed glaciers in Scandinavia, we found that the largest glacier advance at Okstindan was not associated with the "Little Ice Age", but rather to an earlier period centered about AD 700. Periods with glacier advances are all associated with periods of increased winter precipitation along the coast of Norway and hence a stronger effect of the westerlies, where differences in the distribution of precipitation are assumed to reflect changes in the position of the westerlies.

Premonitory acoustic emissions and stick-slip in natural and smooth-faulted Westerly granite

Science.gov (United States)

Thompson, B.D.; Young, R.P.; Lockner, David A.

2009-01-01

A stick-slip event was induced in a cylindrical sample of Westerly granite containing a preexisting natural fault by loading at constant confining pressure of 150 MPa. Continuously recorded acoustic emission (AE) data and computer tomography (CT)-generated images of the fault plane were combined to provide a detailed examination of microscale processes operating on the fault. The dynamic stick-slip event, considered to be a laboratory analog of an earthquake, generated an ultrasonic signal that was recorded as a large-amplitude AE event. First arrivals of this event were inverted to determine the nucleation site of slip, which is associated with a geometric asperity on the fault surface. CT images and AE locations suggest that a variety of asperities existed in the sample because of the intersection of branch or splay faults with the main fault. This experiment is compared with a stick-slip experiment on a sample prepared with a smooth, artificial saw-cut fault surface. Nearly a thousand times more AE were observed for the natural fault, which has a higher friction coefficient (0.78 compared to 0.53) and larger shear stress drop (140 compared to 68 MPa). However at the measured resolution, the ultrasonic signal emitted during slip initiation does not vary significantly between the two experiments, suggesting a similar dynamic rupture process. We propose that the natural faulted sample under triaxial compression provides a good laboratory analogue for a field-scale fault system in terms of the presence of asperities, fault surface heterogeneity, and interaction of branching faults. ?? 2009.

Combining radar and direct observation to estimate pelican collision risk at a proposed wind farm on the Cape west coast, South Africa.

Science.gov (United States)

Jenkins, Andrew R; Reid, Tim; du Plessis, Johan; Colyn, Robin; Benn, Grant; Millikin, Rhonda

2018-01-01

Pre-construction assessments of bird collision risk at proposed wind farms are often confounded by insufficient or poor quality data describing avian flight paths through the development area. These limitations can compromise the practical value of wind farm impact studies. We used radar- and observer-based methods to quantify great white pelican flights in the vicinity of a planned wind farm on the Cape west coast, South Africa, and modelled turbine collision risk under various scenarios. Model outputs were combined with pre-existing demographic data to evaluate the possible influence of the wind farm on the pelican population, and to examine impact mitigation options. We recorded high volumes of great white pelican movement through the wind farm area, coincident with the breeding cycle of the nearby colony and associated with flights to feeding areas located about 50 km away. Pelicans were exposed to collision risk at a mean rate of 2.02 High Risk flights.h-1. Risk was confined to daylight hours, highest during the middle of the day and in conditions of strong north-westerly winds, and 82% of High Risk flights were focused on only five of the proposed 35 turbine placements. Predicted mean mortality rates (22 fatalities.yr-1, 95% Cl, 16-29, with average bird and blade speeds and 95% avoidance rates) were not sustainable, resulting in a negative population growth rate (λ = 0.991). Models suggested that removal of the five highest risk turbines from the project, or institution of a curtailment regimen that shuts down at least these turbines at peak traffic times, could theoretically reduce impacts to manageable levels. However, in spite of the large quantities of high quality data used in our analyses, our collision risk model remains compromised by untested assumptions about pelican avoidance rates and uncertainties about the existing dynamics of the pelican population, and our findings are probably not reliable enough to ensure sustainable development.

Embriogénesis somática de Citrus macrophylla Wester con el empleo del Pectimorf® y análogos de brasinoesteroides

Directory of Open Access Journals (Sweden)

Lourdes Bao Fundora

2013-01-01

Full Text Available Título en ingles: Somatic embryogenesis of Citrus macrophylla Wester using Pectimorf® and analogues of brassinosteroids Resumen Los cítricos son frutales muy utilizados como patrones de injerto. Para incrementar la cantidad de estos cultivos en las plantaciones citrícolas, se pueden usar técnicas de propagación in vitro como la embriogénesis somática, que requiere medios de cultivos artificiales y fitohormonas. Debido a los altos costos de las fitohormonas, una alternativa cubana es el uso de biorreguladores del crecimiento de producción nacional como: los análogos de brasinoesteroides: 25(R 2α, 3α, dihidroxi 5α espirostan- 6-ona (Biobras-6 y C: 25(R 2α, 3α, 5α, trihidroxiespirostan-6-ona (MH-5 y una mezcla de oligogalacturónido de grado de polimerización entre 10-14 (Pectimorf®.  Estos biorreguladores son efectivos en los procesos morfogenéticos como sustitutos o complemento de las auxinas y citoquininas. El presente trabajo estuvo dirigido a determinar el efecto del Pectimorf® y los brasinoesteroides como sustitutos de las fitohormonas tradicionales en el desarrollo de la embriogénesis somática y en la obtención de una línea celular embriogénica de Citrus macrophylla Wester. Se utilizó el medio de cultivo de Murashige y Skoog (MS (1962, suplementado con los biorreguladores del crecimiento MH-5, Biobras-6 y Pectimorf®. Mediante la embriogénesis somática se obtuvieron embriones, raíces y plántulas, en todos los tratamientos. En la formación de plántulas estos biorreguladores fueron muy efectivos. Palabras clave: cultivo in vitro; Citrus; biorreguladores del crecimiento. Abstract Citrus fruits are widely used as rootstock. To increase the amount of these crops in plantations, in vitro propagation techniques such as somatic embryogenesis can be used, which requires artificial culture media and plant hormones. Due to the high cost of the plant hormone, a Cuban alternative is the use of cuban bioregulators growth

Wind turbines, is it just wind?

International Nuclear Information System (INIS)

Boiteux, M.

2012-01-01

The author first outlines that wind energy is not only random, but almost absent in extreme situations when it would be needed (for example and notably, very cold weather without wind). He suggests the association of a gas turbine to each wind turbine, so that the gas turbine will replace non operating wind turbines. He notices that wind turbines are not proximity energy as they were said to be, and that profitability in fact requires tens of grouped giant wind turbines. He also outlines the high cost of construction of grids for the connection of these wind turbines. Thus, he states that wind energy is far from being profitable in the present conditions of electricity tariffs in France

Potential bias in estimates of abundance and distribution of North Sea cod (Gadus morhua) due to strong winds prevailing prior or during a survey

DEFF Research Database (Denmark)

Wieland, Kai; Olesen, Hans Jakob; Pedersen, Eva Maria

2011-01-01

The impact of strong winds on catches of cod (Gadus morhua) was studied using different fishing methods during small-scale surveys with commercial fishing vessels in the north-eastern central North Sea. Catch per unit effort of a flyshooter and a trawler were considerably lower in the shallower c...

Wind: new wind markets

International Nuclear Information System (INIS)

Cameron, A.

2005-01-01

The June 2005 edition of 'Wind Force 12' suggests that wind could generate 12% of global electricity requirements by 2020. But what moves a potential market into an emerging one? Geographical factors include a good wind resource, plenty of open space and the ability to get the generated electricity to end-users. A country's political framework is equally important, with fixed price systems, renewable quota systems and political will all playing a part. Some potential wind markets around the world are thought to have the conditions necessary to become key players in the wind industry. The emerging markets in countries such as Australia, Brazil, Canada, France, Japan and the Philippines are highlighted as examples

Grid Integration of Offshore Wind | Wind | NREL

Science.gov (United States)

Grid Integration of Offshore Wind Grid Integration of Offshore Wind Much can be learned from the existing land-based integration research for handling the variability and uncertainty of the wind resource Arklow Bank offshore wind park consists of seven GE Wind 3.6-MW wind turbines. Integration and

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.

Windiness spells in SW Europe since the last glacial maximum

NARCIS (Netherlands)

Costas, S.; Naugthon, P.; Goble, R.; Renssen, H.

2016-01-01

Dunefields have a great potential to unravel past regimes of atmospheric circulation as they record direct traces of this component of the climate system. Along the Portuguese coast, transgressive dunefields represent relict features originated by intense and frequent westerly winds that largely

Hydrographic features of the western Bay of Bengal in the upper 500 m under the influence of NE and SW monsoon

Digital Repository Service at National Institute of Oceanography (India)

Suryanarayana, A.; Murty, V.S.N.; Sarma, Y.V.B.; Babu, M.T.; Rao, D.P.; Sastry, J.S.

considerable variation in space from season to season. The variations are mainly influencEd. by the seasonal winds and fresh water discharge from major rivers located all along the periphery of the Bay. The near surface flow is mainly south westerly during NE...

Decadal variability on the Northwest European continental shelf

Science.gov (United States)

Jones, Sam; Cottier, Finlo; Inall, Mark; Griffiths, Colin

2018-02-01

Decadal scale time series of the shelf seas are important for understanding both climate and process studies. Despite numerous investigations of long-term temperature variability in the shelf seas, studies of salinity variability are few. Salt is a more conservative tracer than temperature in shallow seas, and it can reveal changes in local hydrographic conditions as well as transmitted basin-scale changes. Here, new inter-annual salinity time series on the northwest European shelf are developed and a 13 year high resolution salinity record from a coastal mooring in western Scotland is presented and analysed. We find strong temporal variability in coastal salinity on timescales ranging from tidal to inter-annual, with the magnitude of variability greatest during winter months. There is little seasonality and no significant decadal trend in the coastal time series of salinity. We propose 4 hydrographic states to explain salinity variance in the shelf area west of Scotland based on the interaction between a baroclinic coastal current and wind-forced barotropic flow: while wind forcing is important, we find that changes in the buoyancy-driven flow are more likely to influence long-term salinity observations. We calculate that during prevailing westerly wind conditions, surface waters in the Sea of the Hebrides receive a mix of 62% Atlantic origin water to 38% coastal sources. This contrasts with easterly wind conditions, during which the mix is 6% Atlantic to 94% coastal sources on average. This 'switching' between hydrographic states is expected to impact nutrient transport and therefore modify the level of primary productivity on the shelf. This strong local variability in salinity is roughly an order of magnitude greater than changes in the adjacent ocean basin, and we infer from this that Scottish coastal waters are likely to be resilient to decadal changes in ocean climate.

Siemens Wind Power 3.6 MW wind turbines for large offshore wind farms

Energy Technology Data Exchange (ETDEWEB)

Akhmatov, Vladislav; Nygaard Nielsen, Joergen; Thisted, Jan; Groendahl, Erik; Egedal, Per; Noertoft Frydensbjerg, Michael; Jensen, Kim Hoej [Siemens Wind Power A/S, Brande (Denmark)

2008-07-01

Siemens Wind power A/S is the key player on the offshore wind power market. The Siemens Wind Power 3.6 MW variable-speed wind turbine is among the word's largest, most advanced and competitive wind turbines with a solid portfolio of large offshore wind farms. Transmission system operators and developers require dynamic wind turbine models for evaluation of fault-ride-through capability and investigations of power system stability. The even larger size of the on- and offshore wind farms has entailed that the grid impact of the voltage and frequency control capability of the wind farm can be appropriated modelled and evaluated. Siemens Wind Power has developed a dynamic model of the 3.6 MW variable-speed wind turbine with the fault-ride-through sequences and models of the voltage and frequency controllers to be applied for large offshore wind farms. The dynamic models have been implemented in the commercially available simulation tools such as DIgSILENT PowerFactory and Siemens PTI PSS/E and successfully validated from measurements. (orig.)

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)

Short time-scale wind forced variability in the Río de la Plata Estuary and its role on ichthyoplankton retention

Science.gov (United States)

Simionato, C. G.; Berasategui, A.; Meccia, V. L.; Acha, M.; Mianzan, H.

2008-01-01

The Río de la Plata Estuary presents a strong bottom salinity front located over a submerged shoal. Apparently favored by retention processes, it is a spawning ground for several coastal fishes. This estuary is very shallow and essentially wind driven and, moreover, in time scales relevant to biota, estuarine circulation is wind dominated and highly variable. Two intriguing questions are, therefore, how this system can favor retention and what the involved mechanisms are. This paper qualitatively explores mechanisms involved in the estuary where retention is favored applying numerical simulations in which neutral particles - simulating fish eggs and early larvae - are released along the bottom frontal zone and tracked for different wind conditions. Results suggest that retentive features can be a consequence of estuarine response to natural wind variability acting over bathymetric features. For winds from most directions, particles either remain trapped near their launching position or move northeastward to southwestward along the shoal. As alternation of winds that favor along-shoal motion is the dominant feature of wind variability in the region, a retentive scenario results from prevailing wind variability. Additionally, winds that tend to export particles with a poor chance of being restored to the front are neither frequent nor persistent. Results show, therefore, that physical forcing alone might generate a retentive scenario at the inner part of this estuary. The physical retention mechanism is more effective for bottom than for surface launched particles. Wind statistics indicate that the proposed mechanism has different implications for retention along the seasons. Spring is the most favorable season, followed by summer, when particles would have a larger propensity to reach the southern area of the estuary (Samborombón Bay). Fall and winter are increasingly less favorable. All these features are consistent with patterns observed in the region in

The phase differences of the interdecadal variabilities of tropical cyclone activity in the peak and late seasons over the western North Pacific

Science.gov (United States)

Fan, Tingting; Xu, Shibin; Huang, Fei; Zhao, Jinping

2018-04-01

This study compares the interdecadal variations in tropical cyclone (TC) activities over the western North Pacific (WNP) basin during the peak season (July-September) and late season (October-December) of 1955-2014 and explores the possible physical mechanisms behind the variations. Both the peak- and late-season tropical storm (TS) days show distinct interdecadal variations, while the late-season TS days lead the peak-season TS days by approximately 4 years on an interdecadal time scale. The late-season TC activity is related to the east-west sea surface temperature (SST) gradient across the equatorial Pacific. The westerly winds induced by the SST gradient can reduce the vertical wind shear and increase the low-level vorticity, which favors TC genesis over the TC genesis region. The peak-season TC activity appears to relate to the SST gradient between the Indian Ocean and the Central Pacific. The westerly wind induced by the SST gradient can reduce the vertical wind shear and increase the mid-level relative humidity, thereby enhancing the TC activity. The full picture of the interdecadal variation in the WNP TC activity during the peak and late seasons revealed in this study provides a new perspective on the seasonal TC forecasts and future projections.

Wind resource estimation and siting of wind turbines

DEFF Research Database (Denmark)

Lundtang Petersen, Erik; Mortensen, N.G.; Landberg, L.

1994-01-01

Detailed knowledge of the characteristics of the natural wind is necessary for the design, planning and operational aspect of wind energy systems. Here, we shall only be concerned with those meteorological aspects of wind energy planning that are termed wind resource estimation. The estimation...... of the wind resource ranges from the overall estimation of the mean energy content of the wind over a large area - called regional assessment - to the prediction of the average yearly energy production of a specific wind turbine at a specific location - called siting. A regional assessment will most often...... lead to a so-called wind atlas. A precise prediction of the wind speed at a given site is essential because for aerodynamic reasons the power output of a wind turbine is proportional to the third power of the wind speed, hence even small errors in prediction of wind speed may result in large deviations...

Wind power production: from the characterisation of the wind resource to wind turbine technologies

International Nuclear Information System (INIS)

Beslin, Guy; Multon, Bernard

2016-01-01

Illustrated by graphs and tables, this article first describes the various factors and means related to the assessment of wind resource in the World, in Europe, and the factors which characterize a local wind resource. In this last respect, the authors indicate how local topography is taken into account to calculate wind speed, how time variations are taken into account (at the yearly, seasonal or daily level), the different methods used to model a local wind resource, how to assess the power recoverable by a wind turbine with horizontal axis (notion of Betz limit). In the second part, the authors present the different wind turbines, their benefits and drawbacks: vertical axis, horizontal axis (examples of a Danish-type wind turbine, of wind turbines designed for extreme conditions). Then, they address the technology of big wind turbines: evolution of technology and of commercial offer, aerodynamic characteristics of wind turbine and benefit of a varying speed (technological solutions, importance of the electric generator). They describe how to choose a wind turbine, how product lines are organised, how the power curve and energy capacity are determined. The issue of integration of wind energy into the power system is then addressed. The next part addressed the economy of wind energy production (annualized production cost, order of magnitude of wind electric power production cost). Future trends are discussed and offshore wind energy production is briefly addressed

Nuclear energy is not the prevailing energy in the French energetic mix

International Nuclear Information System (INIS)

Destais, G.

2011-01-01

The author first shows that the share of nuclear energy in the French electricity production is in fact of 76% (and not 80% as usually said), and that the share of this energy in the final electricity consumption was 69% in 2009. She also outlines that nuclear electricity is only 16,5% of the total final energy consumption in France in 2009, whereas oil still prevails with 42%

Wind farm project economics : value of wind

Energy Technology Data Exchange (ETDEWEB)

Bills-Everett, T. [Mainstream Renewable Power, Toronto, ON (Canada)

2010-07-01

This PowerPoint presentation discussed methods of increasing the value of wind power projects. Appropriate turbine selection and layout is needed to ensure that wind resources are fully developed. Construction costs have a significant impact on project costs. The world turbine price index has not significantly fluctuated since 2006. Operating costs, and the value of wind power projects, are linked with OPEX fluctuations. Wind power projects can significantly reduce greenhouse gas (GHG) emissions. An increase in wind power capacity will reduce the overall cost of energy produced from wind power. Countries can use wind power as part of a renewable energy portfolio designed to reduce risks related to diminishing petroleum supplies. Wind power will help to ensure a global transition to renewable energy use. tabs., figs.

Wind Power Today: Wind Energy Program Highlights 2001

Energy Technology Data Exchange (ETDEWEB)

2002-05-01

Wind Power Today is an annual publication that provides an overview of the U.S. Department of Energy's Wind Energy Program accomplishments for the previous year. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers about the advantages and potential for widespread deployment of wind energy; explain the program's objectives and goals; describe the program's accomplishments in research and application; examine the barriers to widespread deployment; describe the benefits of continued research and development; facilitate technology transfer; and attract cooperative wind energy projects with industry. This 2001 edition of Wind Power Today also includes discussions about wind industry growth in 2001, how DOE is taking advantage of low wind speed regions through advancing technology, and distributed applications for small wind turbines.

Impact of North America on the aerosol composition in the North Atlantic free troposphere

Directory of Open Access Journals (Sweden)

M. I. García

2017-06-01

Full Text Available In the AEROATLAN project we study the composition of aerosols collected over  ∼  5 years at Izaña Observatory (located at  ∼  2400 m a.s.l. in Tenerife, the Canary Islands under the prevailing westerly airflows typical of the North Atlantic free troposphere at subtropical latitudes and midlatitudes. Mass concentrations of sub-10 µm aerosols (PM10 carried by westerly winds to Izaña, after transatlantic transport, are typically within the range 1.2 and 4.2 µg m−3 (20th and 80th percentiles. The main contributors to background levels of aerosols (PM10 within the 1st–50th percentiles  =  0.15–2.54 µg m−3 are North American dust (53 %, non-sea-salt sulfate (14 % and organic matter (18 %. High PM10 events (75th–95th percentiles  ≈  4.0–9.0 µg m−3 are prompted by dust (56 %, organic matter (24 % and non-sea-salt sulfate (9 %. These aerosol components experience a seasonal evolution explained by (i their spatial distribution in North America and (ii the seasonal shift of the North American outflow, which migrates from low latitudes in winter (∼  32° N, January–March to high latitudes in summer (∼  52° N, August–September. The westerlies carry maximum loads of non-sea-salt sulfate, ammonium and organic matter in spring (March–May, of North American dust from midwinter to mid-spring (February–May and of elemental carbon in summer (August–September. Our results suggest that a significant fraction of organic aerosols may be linked to sources other than combustion (e.g. biogenic; further studies are necessary for this topic. The present study suggests that long-term evolution of the aerosol composition in the North Atlantic free troposphere will be influenced by air quality policies and the use of soils (potential dust emitter in North America.

Tropospheric mixing ratios of NO and NOy obtained during TROPOZ II in the latitude region 67 deg N-56 deg S

Energy Technology Data Exchange (ETDEWEB)

Rohrer, F.; Bruening, D.; Ehhalt, D.H. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

1997-12-31

Tropospheric mixing ratios of NO and NOy were measured along the flight track of the TROPOZ II aircraft campaign. These measurements cover regions along the east coast of North America, the Pacific and Atlantic coast of South America and the Atlantic coast of North Africa and Europe. The meteorological conditions are close to the climatological mean: westerly winds at high and mid latitudes, variable and weak winds at low latitudes. (author) 2 refs.

Tropospheric mixing ratios of NO and NOy obtained during TROPOZ II in the latitude region 67 deg N-56 deg S

Energy Technology Data Exchange (ETDEWEB)

Rohrer, F; Bruening, D; Ehhalt, D H [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Atmosphaerische Chemie

1998-12-31

Tropospheric mixing ratios of NO and NOy were measured along the flight track of the TROPOZ II aircraft campaign. These measurements cover regions along the east coast of North America, the Pacific and Atlantic coast of South America and the Atlantic coast of North Africa and Europe. The meteorological conditions are close to the climatological mean: westerly winds at high and mid latitudes, variable and weak winds at low latitudes. (author) 2 refs.

A study of quasi-biennial oscillation in the tropical stratosphere

Science.gov (United States)

Sasi, M. N.; Krishna Murthy, B. V.

1991-12-01

The characteristics of the quasi-biennial oscillation in zonal wind and temperature at Trivandrum (8.5°N, 77°E) have been studied using data covering 16 years. Similar study has been carried out for zonal wind at Balasore (21.5°N, 87°E) using data covering 9 years. The cycle to cycle variation of amplitudes, their altitude variation, periods and descent rates of the westerly and easterly regimes have been studied.

Proceedings of the Canadian Wind Energy Association's 2009 wind matters conference : wind and power systems

International Nuclear Information System (INIS)

2009-01-01

This conference provided a forum for wind energy and electric power industry experts to discuss issues related to wind and power systems. An overview of wind integration studies and activities in Canada and the United States was provided. New tools and technologies for facilitating the integration of wind and improve market conditions for wind energy developers were presented. Methods of increasing wind penetration were evaluated, and technical issues related to wind interconnections throughout North America were reviewed. The conference was divided into the following 5 sessions: (1) experiences with wind integration, and lessons learned, (2) update on ongoing wind integration initiatives in Canada and the United States, (3) initiatives and tools to facilitate wind integration and market access, (4) developments in wind interconnection and grid codes, (5) wind energy and cold weather considerations, and (6) challenges to achieving the 20 per cent WindVision goal in Canada. The conference featured 21 presentations, of which 13 have been catalogued separately for inclusion in this database. refs., tabs., figs

False-positive findings in mammography screening induces short-term distress - breast cancer-specific concern prevails longer

DEFF Research Database (Denmark)

Aro, A R; Pilvikki Absetz, S; van Elderen, T M

2000-01-01

-ups at 2 and 12 months postscreening. At 2 months, there was a moderate multivariate effect of group on distress; and intrusive thinking and worry about breast cancer, in particular, were most frequent amongst the false positives. Intrusive thinking still prevailed at 12 months, in addition to a higher...... findings (n=1407), false-positive findings (n=492) and referents from outside the screening programme (n=1718, age 48-49 years). Distress was measured as illness worry, anxiety, depression, cancer beliefs and early detection behaviour. Measurements were one month before screening invitation with follow...... perceived breast cancer risk and susceptibility. Distress related to screening and false-positive findings seems to be moderate, but prevailing cancer-specific concerns call for improvements in screening programmes....

Kappa-Electrons Downstream of the Solar Wind Termination Shock

Science.gov (United States)

Fahr, H. J.

2017-12-01

A theoretical description of the solar wind electron distribution function downstream of the termination shock under the influence of the shock-induced injection of overshooting KeV-energetic electrons will be presented. A kinetic phasespace transport equation in the bulk frame of the heliosheath plasma flow is developed for the solar wind electrons, taking into account shock-induced electron injection, convective changes, magnetic cooling processes and whistler wave-induced energy diffusion. Assuming that the local electron distribution under the prevailing Non-LTE conditions can be represented by a local kappa function with a local kappa parameter that varies with the streamline coordinates, we determine the parameters of the resulting, initial kappa distribution for the downstream electrons. From this initial function spectral electron fluxes can be derived and can be compared with those measured by the VOYAGER-1 spacecraft in the range between 40 to 70 KeV. It can then be shown that with kappa values around kappa = 6 one can in fact fit these data very satisfactorily. In addition it is shown that for isentropic electron flows kappa-distributed electrons have to undergo simultaneous changes of both parameters, i.e. kappa and theta, of the electron kappa function. It is also shown then that under the influence of energy sinks and sources the electron flux becomes non-isentropic with electron entropies changing along the streamline.

Wind power today: 1999 Wind Energy program highlights

Energy Technology Data Exchange (ETDEWEB)

Weis-Taylor, Pat

2000-04-06

Wind Power Today is an annual publication that provides an overview for the Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy for the 21st century. Content objectives include: Educate readers about the advantages and potential for widespread deployment of wind energy; explain DOE wind energy program objectives and goals; describe program accomplishments in research and application; examine the barriers to widespread deployment; describe benefits of continued research and development; facilitate technology transfer; attract cooperative wind energy projects with industry.

Wind energy. To produce electricity with the wind

International Nuclear Information System (INIS)

Bareau, Helene

2015-11-01

This guide addresses the different aspects of wind-based power generation. It outlines the role of wind energy to meet objectives related to the share of renewable energies in the French energy mix, that wind energy is actually replacing fossil energies, that it is based on local resources within higher safety and less wastage, that current advances are made to integrate wind energy production into the grid, and that it is a solution to diversify energy production. Some figures are presented and commented, regarding onshore wind energy production in France, the location of wind farms, and wind energy production in comparison with other renewable sources. The operation of a wind turbine is described and the different types of wind turbines are evoked. The issue of wind farm planning with citizen participation is addressed: regional planning, studies of pre-feasibility for location selection, procedure, and content of the impact study (radars, fauna and flora, landscapes, safety, health). Other features are outlined: a planned dismantling, and a globally favourable perception. The next part addresses offshore wind energy: the interesting potential of stronger and more reliable wind at sea (European situation, French opportunities, elements comprised in an offshore wind farm), impacts (on marine ecosystems, on neighbouring localities, and interests for visitors). Economic aspects are then addressed: cost and profitability, economic spin-offs, and perspectives. The last part concerns individuals and the possibilities to participate to wind farm projects or to invest in small wind turbines with some prerequisites (constant and steady winds, installation assessment, required expertise, indispensable preliminary steps, costs, aids and profitability)

Track prediction of very severe cyclone 'Nargis' using high resolution ...

Indian Academy of Sciences (India)

tides (surges) as they cross the coast of India,. Bangladesh and other coasts. Strong winds, heavy and torrential rains and the cumulative effect of storm surges and astronomical tides are the three major elements of tropical cyclone ... Ocean move predominantly along westerly/ northwesterly direction. However, some ...

Wind power integration : From individual wind turbine to wind park as a power plant

NARCIS (Netherlands)

Zhou, Y.

2009-01-01

As power capacities of single wind turbine, single wind park and total wind power installation are continuously increasing, the wind power begins to challenge the safety operation of the power system. This thesis focuses on the grid integration aspects such as the dynamic behaviours of wind power

An evaluation of the WindEye wind lidar

DEFF Research Database (Denmark)

Dellwik, Ebba; Sjöholm, Mikael; Mann, Jakob

Prevision of the wind field by remote sensing wind lidars has the potential to improve the performance of wind turbines. The functionality of a WindEye lidar developed by Windar Photonics A/S (Denmark) for the wind energy market was tested in a two months long field experiment. The WindEye sensor...... with a high accuracy during the whole campaign....

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...

An Appropriate Wind Model for Wind Integrated Power Systems Reliability Evaluation Considering Wind Speed Correlations

Directory of Open Access Journals (Sweden)

Rajesh Karki

2013-02-01

Full Text Available Adverse environmental impacts of carbon emissions are causing increasing concerns to the general public throughout the world. Electric energy generation from conventional energy sources is considered to be a major contributor to these harmful emissions. High emphasis is therefore being given to green alternatives of energy, such as wind and solar. Wind energy is being perceived as a promising alternative. This source of energy technology and its applications have undergone significant research and development over the past decade. As a result, many modern power systems include a significant portion of power generation from wind energy sources. The impact of wind generation on the overall system performance increases substantially as wind penetration in power systems continues to increase to relatively high levels. It becomes increasingly important to accurately model the wind behavior, the interaction with other wind sources and conventional sources, and incorporate the characteristics of the energy demand in order to carry out a realistic evaluation of system reliability. Power systems with high wind penetrations are often connected to multiple wind farms at different geographic locations. Wind speed correlations between the different wind farms largely affect the total wind power generation characteristics of such systems, and therefore should be an important parameter in the wind modeling process. This paper evaluates the effect of the correlation between multiple wind farms on the adequacy indices of wind-integrated systems. The paper also proposes a simple and appropriate probabilistic analytical model that incorporates wind correlations, and can be used for adequacy evaluation of multiple wind-integrated systems.

Site-Specific Atmospheric Dispersion Characteristics of Korean Nuclear Power Plant Sites

International Nuclear Information System (INIS)

Han, M. H.; Kim, E. H.; Suh, K. S.; Hwang, W. T.; Choi, Y. G.

2001-01-01

Site-specific atmospheric dispersion characteristics have been analyzed. The northwest and the southwest wind prevail on nuclear sites of Korea. The annual isobaric surface averaged for twenty years around Korean peninsula shows that west wind prevails. The prevailing west wind is profitable in the viewpoint of radiation protection because three of four nuclear sites are located in the east side. Large scale field tracer experiments over nuclear sites have been conducted for the purpose of analyzing the atmospheric dispersion characteristics and validating a real-time atmospheric dispersion and dose assessment system FADAS. To analyze the site-specific atmospheric dispersion characteristics is essential for making effective countermeasures against a nuclear emergency

Hygienic features of working conditions prevailing in X-ray cabinets

International Nuclear Information System (INIS)

Usol'tsev, V.I.; Serebryanyj, V.A.

1975-01-01

The results of an investigation of 352 x-ray cabinets showed that their personnel is subjected to simultaneous action of a number of factors: discomfortable microclimate, small concentrations of ozone and nitrogen oxides (within 0.1 of the maximum permissible concentration). The hands of the personnel, especially those of the x-ray laboratory assistants are contaminated with lead (2.38mg in the hands washings). Therefore the assessment of labour conditions prevailing in an x-ray cabinet and the accomplishment of measures of their provement should be carried out with due regards to all the complex of the above mentioned factors besides the ionizing radiation

Skeletal-related events significantly impact health-related quality of life in metastatic castration-resistant prostate cancer: data from PREVAIL and AFFIRM trials.

Science.gov (United States)

Saad, F; Ivanescu, C; Phung, D; Loriot, Y; Abhyankar, S; Beer, T M; Tombal, B; Holmstrom, S

2017-03-01

We investigated the impact of skeletal-related events (SREs) on health-related quality of life (HRQoL) in patients with metastatic castration-resistant prostate cancer (mCRPC) in phase III trials of enzalutamide versus placebo. Patients with mCRPC experiencing at least one SRE during AFFIRM and PREVAIL were assessed for trajectory-adjusted mean change in HRQoL by first SRE using Functional Assessment of Cancer Therapy-Prostate (FACT-P; AFFIRM, three domains, and PREVAIL, nine domains) and EQ-5D (PREVAIL) instruments. First SREs caused HRQoL deterioration in both trials. Spinal cord compression had the largest impact, with clinically meaningful reductions in seven of nine FACT-P domains in PREVAIL and all three in AFFIRM (mean (95% confidence interval (CI)) change in FACT-P total score -16.95 (-26.47, -7.44) and -9.69 (-16.10, -3.27), respectively). In PREVAIL, first SREs caused clinically meaningful declines in EQ-5D utility index, irrespective of category; spinal cord compression had the largest impact (mean (95% CI) change -0.24 (-0.39, -0.08)). In AFFIRM, FACT-P and FACT-General total scores showed clinically meaningful declines after radiation/surgery to bone. SREs were associated with clinically meaningful functional declines in the daily lives of patients with mCRPC. Spinal cord compression had the largest impact on HRQoL.

5-Year Outcomes After Left Atrial Appendage Closure: From the PREVAIL and PROTECT AF Trials.

Science.gov (United States)

Reddy, Vivek Y; Doshi, Shephal K; Kar, Saibal; Gibson, Douglas N; Price, Matthew J; Huber, Kenneth; Horton, Rodney P; Buchbinder, Maurice; Neuzil, Petr; Gordon, Nicole T; Holmes, David R

2017-12-19

The PROTECT AF (WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation) trial demonstrated that left atrial appendage closure (LAAC) with the Watchman device (Boston Scientific, St. Paul, Minnesota) was equivalent to warfarin for preventing stroke in atrial fibrillation, but had a high rate of complications. In a second randomized trial, PREVAIL (Evaluation of the WATCHMAN LAA Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy), the complication rate was low. The warfarin cohort experienced an unexpectedly low ischemic stroke rate, rendering the efficacy endpoints inconclusive. However, these outcomes were based on relatively few patients followed for a relatively short time. The final results of the PREVAIL trial, both alone and as part of a patient-level meta-analysis with the PROTECT AF trial, are reported with patients in both trials followed for 5 years. PREVAIL and PROTECT AF are prospective randomized clinical trials with patients randomized 2:1 to LAAC or warfarin; together, they enrolled 1,114 patients for 4,343 patient-years. Analyses are by intention-to-treat, and rates are events per 100 patient-years. For the PREVAIL trial, the first composite coprimary endpoint of stroke, systemic embolism (SE), or cardiovascular/unexplained death did not achieve noninferiority (posterior probability for noninferiority = 88.4%), whereas the second coprimary endpoint of post-procedure ischemic stroke/SE did achieve noninferiority (posterior probability for noninferiority = 97.5%); the warfarin arm maintained an unusually low ischemic stroke rate (0.73%). In the meta-analysis, the composite endpoint was similar between groups (hazard ratio [HR]: 0.820; p = 0.27), as were all-stroke/SE (HR: 0.961; p = 0.87). The ischemic stroke/SE rate was numerically higher with LAAC, but this difference did not reach statistical significance (HR: 1.71; p = 0.080). However, differences in

Wind energy

International Nuclear Information System (INIS)

Anon.

1992-01-01

This chapter discusses the role wind energy may have in the energy future of the US. The topics discussed in the chapter include historical aspects of wind energy use, the wind energy resource, wind energy technology including intermediate-size and small wind turbines and intermittency of wind power, public attitudes toward wind power, and environmental, siting and land use issues

A note on the correlation between circular and linear variables with an application to wind direction and air temperature data in a Mediterranean climate

Science.gov (United States)

Lototzis, M.; Papadopoulos, G. K.; Droulia, F.; Tseliou, A.; Tsiros, I. X.

2018-04-01

There are several cases where a circular variable is associated with a linear one. A typical example is wind direction that is often associated with linear quantities such as air temperature and air humidity. The analysis of a statistical relationship of this kind can be tested by the use of parametric and non-parametric methods, each of which has its own advantages and drawbacks. This work deals with correlation analysis using both the parametric and the non-parametric procedure on a small set of meteorological data of air temperature and wind direction during a summer period in a Mediterranean climate. Correlations were examined between hourly, daily and maximum-prevailing values, under typical and non-typical meteorological conditions. Both tests indicated a strong correlation between mean hourly wind directions and mean hourly air temperature, whereas mean daily wind direction and mean daily air temperature do not seem to be correlated. In some cases, however, the two procedures were found to give quite dissimilar levels of significance on the rejection or not of the null hypothesis of no correlation. The simple statistical analysis presented in this study, appropriately extended in large sets of meteorological data, may be a useful tool for estimating effects of wind on local climate studies.

Strategic wind power trading considering rival wind power production

DEFF Research Database (Denmark)

Exizidis, Lazaros; Kazempour, Jalal; Pinson, Pierre

2016-01-01

In an electricity market with high share of wind power, it is expected that wind power producers may exercise market power. However, wind producers have to cope with wind’s uncertain nature in order to optimally offer their generation, whereas in a market with more than one wind producers, uncert...... depending on the rival’s wind generation, given that its own expected generation is not high. Finally, as anticipated, expected system cost is higher when both wind power producers are expected to have low wind power generation......In an electricity market with high share of wind power, it is expected that wind power producers may exercise market power. However, wind producers have to cope with wind’s uncertain nature in order to optimally offer their generation, whereas in a market with more than one wind producers......, uncertainty of rival wind power generation should also be considered. Under this context, this paper addresses the impact of rival wind producers on the offering strategy and profits of a pricemaker wind producer. A stochastic day-ahead market setup is considered, which optimizes the day-ahead schedules...

Dependence between sea surge, river flow and precipitation in south and west Britain

Directory of Open Access Journals (Sweden)

C. Svensson

2004-01-01

Full Text Available Estuaries around Great Britain may be at heightened risk of flooding because of the simultaneous occurrence of extreme sea surge and river flow, both of which may be caused by mid-latitude cyclones. A measure especially suited for extremes was employed to estimate dependence between river flow and sea surge. To assist in the interpretation of why flow-surge dependence occurs in some areas and not in others, the dependence between precipitation and surge and between precipitation and river flow was also studied. Case studies of the meteorological situations leading to high surges and/or river flows were also carried out. The present study concerns catchments draining to the south and west coasts of Great Britain. Statistically significant dependence between river flow and daily maximum sea surge may be found at catchments spread along most of this coastline. However, higher dependence is generally found in catchments in hilly areas with a southerly to westerly aspect. Here, precipitation in south-westerly airflow, which is generally the quadrant of prevailing winds, will be enhanced orographically as the first higher ground is encountered. The sloping catchments may respond quickly to the abundant rainfall and the flow peak may arrive in the estuary on the same day as a large sea surge is produced by the winds and low atmospheric pressure associated with the cyclone. There are three regions where flow-surge dependence is strong: the western part of the English south coast, southern Wales and around the Solway Firth. To reduce the influence of tide-surge interaction on the dependence analysis, the dependence between river flow and daily maximum surge occurring at high tide was estimated. The general pattern of areas with higher dependence is similar to that using the daily maximum surge. The dependence between river flow and daily maximum sea surge is often strongest when surge and flow occur on the same day. The west coast from Wales and

Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

DEFF Research Database (Denmark)

Feng, Ju; Shen, Wen Zhong

2015-01-01

Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distribu...

Association between mean and interannual equatorial Indian Ocean subsurface temperature bias in a coupled model

Science.gov (United States)

Srinivas, G.; Chowdary, Jasti S.; Gnanaseelan, C.; Prasad, K. V. S. R.; Karmakar, Ananya; Parekh, Anant

2018-03-01

In the present study the association between mean and interannual subsurface temperature bias over the equatorial Indian Ocean (EIO) is investigated during boreal summer (June through September; JJAS) in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. Anomalously high subsurface warm bias (greater than 3 °C) over the eastern EIO (EEIO) region is noted in CFSv2 during summer, which is higher compared to other parts of the tropical Indian Ocean. Prominent eastward current bias in the upper 100 m over the EIO region induced by anomalous westerly winds is primarily responsible for subsurface temperature bias. The eastward currents transport warm water to the EEIO and is pushed down to subsurface due to downwelling. Thus biases in both horizontal and vertical currents over the EIO region support subsurface warm bias. The evolution of systematic subsurface warm bias in the model shows strong interannual variability. These maximum subsurface warming episodes over the EEIO are mainly associated with La Niña like forcing. Strong convergence of low level winds over the EEIO and Maritime continent enhanced the westerly wind bias over the EIO during maximum warming years. This low level convergence of wind is induced by the bias in the gradient in the mean sea level pressure with positive bias over western EIO and negative bias over EEIO and parts of western Pacific. Consequently, changes in the atmospheric circulation associated with La Niña like conditions affected the ocean dynamics by modulating the current bias thereby enhancing the subsurface warm bias over the EEIO. It is identified that EEIO subsurface warming is stronger when La Niña co-occurred with negative Indian Ocean Dipole events as compared to La Niña only years in the model. Ocean general circulation model (OGCM) experiments forced with CFSv2 winds clearly support our hypothesis that ocean dynamics influenced by westerly winds bias is primarily

LIDAR Wind Speed Measurements of Evolving Wind Fields

Energy Technology Data Exchange (ETDEWEB)

Simley, E.; Pao, L. Y.

2012-07-01

Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed Taylor's frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations to create a more realistic measurement model. A simple model of wind evolution is applied to a frozen wind field used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements are also evaluated with a large eddy simulation of a stable boundary layer provided by the National Center for Atmospheric Research. Simulation results show the combined effects of LIDAR errors and wind evolution for realistic turbine-mounted LIDAR measurement scenarios.

Wind Energy

International Nuclear Information System (INIS)

Rodriguez D, J.M.

1998-01-01

The general theory of the wind energy conversion systems is presented. The availability of the wind resource in Colombia and the ranges of the speed of the wind in those which is possible economically to use the wind turbines are described. It is continued with a description of the principal technological characteristics of the wind turbines and are split into wind power and wind-powered pumps; and its use in large quantities grouped in wind farms or in autonomous systems. Finally, its costs and its environmental impact are presented

Evaluation of wind farm efficiency and wind turbine wakes at the Nysted offshore wind farm

DEFF Research Database (Denmark)

Barthelmie, Rebecca Jane; Jensen, L.E.

2010-01-01

Here, we quantify relationships between wind farm efficiency and wind speed, direction, turbulence and atmospheric stability using power output from the large offshore wind farm at Nysted in Denmark. Wake losses are, as expected, most strongly related to wind speed variations through the turbine...... thrust coefficient; with direction, atmospheric stability and turbulence as important second order effects. While the wind farm efficiency is highly dependent on the distribution of wind speeds and wind direction, it is shown that the impact of turbine spacing on wake losses and turbine efficiency can...... be quantified, albeit with relatively large uncertainty due to stochastic effects in the data. There is evidence of the ‘deep array effect’ in that wake losses in the centre of the wind farm are under-estimated by the wind farm model WAsP, although overall efficiency of the wind farm is well predicted due...

Wind Power Today: 2000 Wind Energy Program Highlights

Energy Technology Data Exchange (ETDEWEB)

Weis-Taylor, W.

2001-05-08

Wind Power Today is an annual publication that provides an overview of the U.S. Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers about the advantages and potential for widespread deployment of wind energy; explain the program's objectives and goals; describe the program's accomplishments in research and application; examine the barriers to widespread deployment; describe the benefits of continued research and development; facilitate technology transfer; and attract cooperative wind energy projects with industry.

Advancements in Wind Integration Study Data Modeling: The Wind Integration National Dataset (WIND) Toolkit; Preprint

Energy Technology Data Exchange (ETDEWEB)

Draxl, C.; Hodge, B. M.; Orwig, K.; Jones, W.; Searight, K.; Getman, D.; Harrold, S.; McCaa, J.; Cline, J.; Clark, C.

2013-10-01

Regional wind integration studies in the United States require detailed wind power output data at many locations to perform simulations of how the power system will operate under high-penetration scenarios. The wind data sets that serve as inputs into the study must realistically reflect the ramping characteristics, spatial and temporal correlations, and capacity factors of the simulated wind plants, as well as be time synchronized with available load profiles. The Wind Integration National Dataset (WIND) Toolkit described in this paper fulfills these requirements. A wind resource dataset, wind power production time series, and simulated forecasts from a numerical weather prediction model run on a nationwide 2-km grid at 5-min resolution will be made publicly available for more than 110,000 onshore and offshore wind power production sites.

Polar-Tropical Coupling in the Winter Stratosphere

Science.gov (United States)

Scott, R.

2017-12-01

A distinct pattern of enhanced equatorial potential vorticitygradients during QBO westerly anomalies, enhanced subtropicalgradients during QBO easterlies, is used to motivate a new formulationof dynamical coupling between the tropics and winter polar vortexbased on remote transfer of finite amplitude wave activity defined interms of lateral potential vorticity displacements. While the weakpotential vorticity gradients in the surf zone imply laterallyevanescent Rossby waves, transfer of wave activity from the polarvortex edge to the subtropical barrier or to the QBO westerly phaseequatorial gradients arises from nonlocality of potential vorticityinversion and the large horizontal displacements of the vortex edge.Our approach goes beyond the traditional description of the effect ofQBO wind anomalies on linear wave propagation through the stratospherevia wave reflection at the zero wind line; linear wave theory isappealing but neglects the long horizontal and vertical wavelengthsinvolved and the inhomogeneous background potential vorticity. Aparticular issue of outstanding interest is whether and how therelatively shallow QBO anomalies can influence the deep verticallypropagating waves on the edge of the winter stratospheric polarvortex. Process studies with a mechanistic model with prescribed QBOand carefully controlled high-latitude wave forcing are analyzed,guided by a reexamination of meteorological reanalysis, to address howsuch a dynamical linkage may influence in particular the resonantexcitation of the winter vortex, and the occurrence ofvortex-splitting sudden warming events. We quantify the associatedtransfer of wave activity from vortex edge to the tropics, considerunder what conditions this becomes a significant source of easterlymomentum in the driving of the QBO itself, and how the structure ofthe Brewer-Dobson circulation varies in response to the location ofthe QBO westerly winds in any given winter.

Wind Climate Parameters for Wind Turbine Fatigue Load Assessment

DEFF Research Database (Denmark)

Toft, Henrik Stensgaard; Svenningsen, Lasse; Moser, Wolfgang

2016-01-01

Site-specific assessment of wind turbine design requires verification that the individual wind turbine components can survive the site-specific wind climate. The wind turbine design standard, IEC 61400-1 (third edition), describes how this should be done using a simplified, equivalent wind climate...... climate required by the current design standard by comparing damage equivalent fatigue loads estimated based on wind climate parameters for each 10 min time-series with fatigue loads estimated based on the equivalent wind climate parameters. Wind measurements from Boulder, CO, in the United States...

Atmospheric Wind Relaxations and the Oceanic Response in the California Current Large Marine Ecosystem

Science.gov (United States)

Fewings, M. R.; Dorman, C. E.; Washburn, L.; Liu, W.

2010-12-01

On the West Coast of North America in summer, episodic relaxation of the upwelling-favorable winds causes warm water to propagate northward from southern to central California, against the prevailing currents [Harms and Winant 1998, Winant et al. 2003, Melton et al. 2009]. Similar wind relaxations are an important characteristic of coastal upwelling ecosystems worldwide. Although these wind relaxations have an important influence on coastal ocean dynamics, no description exists of the regional atmospheric patterns that lead to wind relaxations in southern California, or of the regional ocean response. We use QuikSCAT wind stress, North American Regional Reanalysis atmospheric pressure products, water temperature and velocity from coastal ocean moorings, surface ocean currents from high-frequency radars, and MODIS satellite sea-surface temperature and ocean color images to analyze wind relaxation events and the ocean response. We identify the events based on an empirical index calculated from NDBC buoy winds [Melton et al. 2009]. We describe the regional evolution of the atmosphere from the Gulf of Alaska to Baja California over the few days leading up to wind relaxations, and the coastal ocean temperature, color, and current response off southern and central California. We analyze ~100 wind relaxation events in June-September during the QuikSCAT mission, 1999-2009. Our results indicate south-central California wind relaxations in summer are tied to mid-level atmospheric low-pressure systems that form in the Gulf of Alaska and propagate southeastward over 3-5 days. As the low-pressure systems reach southern California, the atmospheric pressure gradient along the coast weakens, causing the surface wind stress to relax to near zero. The weak wind signal appears first at San Diego and propagates northward. QuikSCAT data indicate the relaxed winds extend over the entire Southern California Bight and up to 200 km offshore of central California. Atmospheric dynamics in

European Wind Atlas and Wind Resource Research in Denmark

DEFF Research Database (Denmark)

Mortensen, Niels Gylling

to estimate the actual wind climate at any specific site and height within this region. The Danish and European Wind Atlases are examples of how the wind atlas methodology can be employed to estimate the wind resource potential for a country or a sub-continent. Recently, the methodology has also been used...... - from wind measurements at prospective sites to wind tunnel simulations and advanced flow modelling. Among these approaches, the wind atlas methodology - developed at Ris0 National Laboratory over the last 25 years - has gained widespread recognition and is presently considered by many as the industry......-standard tool for wind resource assessment and siting of wind turbines. The PC-implementation of the methodology, the Wind Atlas Analysis and Application Program (WAsP), has been applied in more than 70 countries and territories world-wide. The wind atlas methodology is based on physical descriptions and models...

When real life wind speed exceeds design wind assumptions

Energy Technology Data Exchange (ETDEWEB)

Winther-Jensen, M; Joergensen, E R [Risoe National Lab., Roskilde (Denmark)

1999-03-01

Most modern wind turbines are designed according to a standard or a set of standards to withstand the design loads with a defined survival probability. Mainly the loads are given by the wind conditions on the site defining the `design wind speeds`, normally including extreme wind speeds given as an average and a peak value. The extreme wind speeds are normally (e.g. in the upcoming IEC standard for wind turbine safety) defined as having a 50-year recurrence period. But what happens when the 100 or 10,000 year wind situation hits a wind turbine? Results on wind turbines of wind speeds higher than the extreme design wind speeds are presented based on experiences especially from the State of Gujarat in India. A description of the normal approach of designing wind turbines in accordance with the standards in briefly given in this paper with special focus on limitations and built-in safety levels. Based on that, other possibilities than just accepting damages on wind turbines exposed for higher than design wind speeds are mentioned and discussed. The presentation does not intend to give the final answer to this problem but is meant as an input to further investigations and discussions. (au)

Summer Drivers of Atmospheric Variability Affecting Ice Shelf Thinning in the Amundsen Sea Embayment, West Antarctica

Science.gov (United States)

Deb, Pranab; Orr, Andrew; Bromwich, David H.; Nicolas, Julien P.; Turner, John; Hosking, J. Scott

2018-05-01

Satellite data and a 35-year hindcast of the Amundsen Sea Embayment summer climate using the Weather Research and Forecasting model are used to understand how regional and large-scale atmospheric variability affects thinning of ice shelves in this sector of West Antarctica by melting from above and below (linked to intrusions of warm water caused by anomalous westerlies over the continental shelf edge). El Niño episodes are associated with an increase in surface melt but do not have a statistically significant impact on westerly winds over the continental shelf edge. The location of the Amundsen Sea Low and the polarity of the Southern Annular Mode (SAM) have negligible impact on surface melting, although a positive SAM and eastward shift of the Amundsen Sea Low cause anomalous westerlies over the continental shelf edge. The projected future increase in El Niño episodes and positive SAM could therefore increase the risk of disintegration of West Antarctic ice shelves.

3D WindScanner lidar measurements of wind and turbulence around wind turbines, buildings and bridges

Science.gov (United States)

Mikkelsen, T.; Sjöholm, M.; Angelou, N.; Mann, J.

2017-12-01

WindScanner is a distributed research infrastructure developed at DTU with the participation of a number of European countries. The research infrastructure consists of a mobile technically advanced facility for remote measurement of wind and turbulence in 3D. The WindScanners provide coordinated measurements of the entire wind and turbulence fields, of all three wind components scanned in 3D space. Although primarily developed for research related to on- and offshore wind turbines and wind farms, the facility is also well suited for scanning turbulent wind fields around buildings, bridges, aviation structures and of flow in urban environments. The mobile WindScanner facility enables 3D scanning of wind and turbulence fields in full scale within the atmospheric boundary layer at ranges from 10 meters to 5 (10) kilometers. Measurements of turbulent coherent structures are applied for investigation of flow pattern and dynamical loads from turbines, building structures and bridges and in relation to optimization of the location of, for example, wind farms and suspension bridges. This paper presents our achievements to date and reviews briefly the state-of-the-art of the WindScanner measurement technology with examples of uses for wind engineering applications.

Seasonal cycle of cross-equatorial flow in the central Indian Ocean

Science.gov (United States)

Wang, Yi; McPhaden, Michael J.

2017-05-01

This study investigates the seasonal cycle of meridional currents in the upper layers of central equatorial Indian Ocean using acoustic Doppler current profiler (ADCP) and other data over the period 2004-2013. The ADCP data set collected along 80.5°E is the most comprehensive collection of direct velocity measurements in the central Indian Ocean to date, providing new insights into the meridional circulation in this region. We find that mean volume transport is southward across the equator in the central Indian Ocean in approximate Sverdrup balance with the wind stress curl. In addition, mean westerly wind stress near the equator drives convergent Ekman flow in the surface layer and subsurface divergent geostrophic flow in the thermocline at 50-150 m depths. In response to a mean northward component of the surface wind stress, the maximum surface layer convergence is shifted off the equator to between 0.5° and 1°N. Evidence is also presented for the existence of a shallow equatorial roll consisting of a northward wind-driven surface drift overlaying the southward directed subsurface Sverdrup transport. Seasonal variations are characterized by cross-equatorial transports flowing from the summer to the winter hemisphere in quasi-steady Sverdrup balance with the wind stress curl. In addition, semiannually varying westerly monsoon transition winds lead to semiannual enhancements of surface layer Ekman convergence and geostrophic divergence in the thermocline. These results quantify expectations from ocean circulation theories for equatorial Indian Ocean meridional circulation patterns with a high degree of confidence given the length of the data records.

CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

Energy Technology Data Exchange (ETDEWEB)

Weberg, Micah J. [PhD Candidate in Space Science, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2134A Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Lepri, Susan T. [Associate Professor, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2429 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Zurbuchen, Thomas H., E-mail: mjweberg@umich.edu, E-mail: slepri@umich.edu, E-mail: thomasz@umich.edu [Professor, Space Science and Aerospace Engineering, Associate Dean for Entrepreneurship Senior Counselor of Entrepreneurship Education, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2431 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States)

2015-03-10

The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space.

CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

International Nuclear Information System (INIS)

Weberg, Micah J.; Lepri, Susan T.; Zurbuchen, Thomas H.

2015-01-01

The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space

Wind Turbine Converter Control Interaction with Complex Wind Farm Systems

DEFF Research Database (Denmark)

Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

2013-01-01

. The same wind turbine converter control strategy is evaluated in two different wind farms. It is emphasised that the grid-side converter controller should be characterised by sufficient harmonic/noise rejection and adjusted depending on wind farms to which it is connected. Various stability indices......This study presents wind turbine converter stability analysis of wind farms in frequency domain. The interaction between the wind turbine control system and the wind farm structure in wind farms is deeply investigated. Two wind farms (i.e. Horns Rev II and Karnice) are taken into consideration...... in this study. It is shown that wind farm components, such as long high-voltage alternating current cables and park transformers, can introduce significant low-frequency series resonances seen from the wind turbine terminals that can affect wind turbine control system operation and overall wind farm stability...

The Wind Integration National Dataset (WIND) toolkit (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Caroline Draxl: NREL

2014-01-01

Regional wind integration studies require detailed wind power output data at many locations to perform simulations of how the power system will operate under high penetration scenarios. The wind datasets that serve as inputs into the study must realistically reflect the ramping characteristics, spatial and temporal correlations, and capacity factors of the simulated wind plants, as well as being time synchronized with available load profiles.As described in this presentation, the WIND Toolkit fulfills these requirements by providing a state-of-the-art national (US) wind resource, power production and forecast dataset.

Wind power

International Nuclear Information System (INIS)

Gipe, P.

2007-01-01

This book is a translation of the edition published in the USA under the title of ''wind power: renewable energy for home, farm and business''. In the wake of mass blackouts and energy crises, wind power remains a largely untapped resource of renewable energy. It is a booming worldwide industry whose technology, under the collective wing of aficionados like author Paul Gipe, is coming of age. Wind Power guides us through the emergent, sometimes daunting discourse on wind technology, giving frank explanations of how to use wind technology wisely and sound advice on how to avoid common mistakes. Since the mid-1970's, Paul Gipe has played a part in nearly every aspect of wind energy development from installing small turbines to promoting wind energy worldwide. As an American proponent of renewable energy, Gipe has earned the acclaim and respect of European energy specialists for years, but his arguments have often fallen on deaf ears at home. Today, the topic of wind power is cropping up everywhere from the beaches of Cape Cod to the Oregon-Washington border, and one wind turbine is capable of producing enough electricity per year to run 200 average American households. Now, Paul Gipe is back to shed light on this increasingly important energy source with a revised edition of Wind Power. Over the course of his career, Paul Gipe has been a proponent, participant, observer, and critic of the wind industry. His experience with wind has given rise to two previous books on the subject, Wind Energy Basics and Wind Power for Home and Business, which have sold over 50,000 copies. Wind Power for Home and Business has become a staple for both homeowners and professionals interested in the subject, and now, with energy prices soaring, interest in wind power is hitting an all-time high. With chapters on output and economics, Wind Power discloses how much you can expect from each method of wind technology, both in terms of energy and financial savings. The book updated models

Energy output estimation for a small wind turbine positioned on a rooftop in the urban environment with and without a duct

Energy Technology Data Exchange (ETDEWEB)

Beller, C.

2011-05-15

Nowadays, wind turbines in general, but also urban wind turbines attained acceptance to a certain extend. Conceptual designs and some examples in reality exist, where small-scale wind turbines have been implemented close to buildings or even integrated in the building structure. This work is aiming to estimate how much energy a wind turbine could produce in the built environment, depending on its integration and configuration. On the basis of measurements taken on the rooftop of H.C. Orsted Institut in Copenhagen, which is located in an urban area, a comparison of fictive free standing turbines with ducted turbines of the same type was carried out. First, a prevailing wind energy direction was detected with rough mean velocity and frequency calculations. Next, a duct was aligned with the direction, where the highest energy potential was found. Further calculations were conducted with more detailed wind velocity distributions, depending on the wind direction sectors. The duct's wind velocity amplification capability was set to 14%, while a total opening angle of 30. was assumed to be accessible from both sides. With the simplifying assumptions and the uncertainties at the location of measurement, the free standing turbines had an energy potential of 300kWh/m2/a for the horizontal axis wind turbine (HAWT) and for the vertical axis wind turbine (VAWT) 180kWh/m2/a. For the ducted turbines an energy output of 180kWh/m2/a was found for the HAWT configuration, while the VAWT configuration reached an output of 110kWh/m2/a. The available wind had an energy potential of 730kWh/m2/a. Evaluating these results it seems a free standing turbine is preferable, when only considering the power output, whereas the ducted version comprises properties, which are important considering the requirements needed in the inhabited area such as safety and noise issues. (Author)

Marine wind data presentation using wind transition matrix

Digital Repository Service at National Institute of Oceanography (India)

Mascarenhas, A.J.; Gouveia, A.D.; Desai, R.G.P.

One of the methods to simulate the random wind behaviour through time is to use historical wind data presented in the form of wind transition matrix. Here it is assumed that, the probability that the wind will shift from one direction to another...

Wind power forecast error smoothing within a wind farm

International Nuclear Information System (INIS)

Saleck, Nadja; Bremen, Lueder von

2007-01-01

Smoothing of wind power forecast errors is well-known for large areas. Comparable effects within a wind farm are investigated in this paper. A Neural Network was taken to predict the power output of a wind farm in north-western Germany comprising 17 turbines. A comparison was done between an algorithm that fits mean wind and mean power data of the wind farm and a second algorithm that fits wind and power data individually for each turbine. The evaluation of root mean square errors (RMSE) shows that relative small smoothing effects occur. However, it can be shown for this wind farm that individual calculations have the advantage that only a few turbines are needed to give better results than the use of mean data. Furthermore different results occurred if predicted wind speeds are directly fitted to observed wind power or if predicted wind speeds are first fitted to observed wind speeds and then applied to a power curve. The first approach gives slightly better RMSE values, the bias improves considerably

Wind Power Today: 1998 Wind Energy Program Highlights

Energy Technology Data Exchange (ETDEWEB)

Tromly, K.

1999-06-17

The US Department of Energy's Office of Energy Efficiency and Renewable Energy manages the Federal Wind Energy Program. The mission of the program is to help the US wind industry to complete the research, testing, and field verification needed to fully develop advanced wind technologies that will lead the world in cost-effectiveness and reliability. This publication, printed annually, provides a summary of significant achievements in wind energy made during the previous calendar year. Articles include wind energy in the Midwest, an Alaskan wind energy project, the US certification program, structural testing, and the federal program in review.

Wind energy: Overcoming inadequate wind and modeling uncertainties

Energy Technology Data Exchange (ETDEWEB)

Kane, Vivek

2010-09-15

'Green Energy' is the call of the day, and significance of Wind Energy can never be overemphasized. But the key question here is - What if the wind resources are inadequate? Studies reveal that the probability of finding favorable wind at a given place on land is only 15%. Moreover, there are inherent uncertainties associated with wind business. Can we overcome inadequate wind resources? Can we scientifically quantify uncertainty and model it to make business sense? This paper proposes a solution, by way of break-through Wind Technologies, combined with advanced tools for Financial Modeling, enabling vital business decisions.

Effects of offshore wind farms on marine wildlife—a generalized impact assessment

Science.gov (United States)

Bergström, Lena; Kautsky, Lena; Malm, Torleif; Rosenberg, Rutger; Wahlberg, Magnus; Åstrand Capetillo, Nastassja; Wilhelmsson, Dan

2014-03-01

Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning.

Operation Design of Wind Turbines in Strong Wind Conditions

DEFF Research Database (Denmark)

Shen, Wen Zhong; Montes, Melissa Barroso; Odgaard, Peter Fogh

2012-01-01

and variable speed pitch regulated wind turbines. The variable speed design is more suitable for wind turbines to run at very high wind speeds which can help the turbine braking system to stop the turbine at the new "cut-out" wind speed. Reference power, rotational speed and pitch angle have been designed...... optimally. In order to reduce the possible increased loading, fatigue due to the wind gusts, control strategies have been considered for both constant sped and variable speed pitch regulated wind turbines. The control study shows that the designed controllers can reduce the standard deviations efficiently......In order to reduce the impact on the electrical grid from the shutdown of MW wind turbines at wind speeds higher than the cut-out wind speed of 25 m/s, we propose in this paper to run the turbines at high wind speeds up to 40 m/s. Two different operation designs are made for both constant speed...

Undesired reinforcement of harmful ‘self-evident truths’ concerning the implementation of wind power

International Nuclear Information System (INIS)

Wolsink, Maarten

2012-01-01

This ‘viewpoint’ draws attention to a lingering, simplistic and faulty interpretation of the complex phenomenon of acceptance of renewables and their implementation in concrete projects by all relevant actors—namely the ‘backyard theory’. During the last decade, research that investigated NIMBY has provided support to disprove the two prime hypotheses (proximity and decreasing property-value). The current mainstream trend in academic circles is clearly towards abandoning NIMBY explanations. However, in practice among developers and policymakers NIMBY thinking still prevails. Unfortunately there is also some academic writing that persists in recycling the ‘backyard theory’—despite ample research to the contrary—thus feeding this faulty interpretation of implementation problems. A recent review of the state of the art of wind power implementation is taken as an example; it presents NIMBY as a common-sense, self-evident truth, while to support this explanation it cites publications that actually refute this view and instead support the mainstream move towards abandoning NIMBY thinking. This shift is important, because further academic support for this concept would serve to hinder rapid deployment of wind power and also other renewables.

Endurance Wind Power : practical insights into small wind

International Nuclear Information System (INIS)

Hicks, D.

2008-01-01

This presentation discussed practical issues related to purchasing and installing small wind turbines in Canada. Wind power capacity can be estimated by looking at provincial wind maps as well as by seeking wind data at local airports. Wind resources are typically measured at heights of between 20 meters and 50 m. The height of a wind turbine tower can significantly increase the turbine's wind generating capacity. Turbine rotors should always be placed 30 feet higher than obstacles within 500 feet. Many provinces have now mandated utilities to accept renewable energy resources from grid-connected wind energy plants. Net billing systems are used to determine the billing relationship between power-producing consumers and the utilities who will buy the excess power and sell it to other consumers. Utilities are not yet mandated to purchase excess power, and it is likely that federal and provincial legislation will be needed to ensure that net billing systems continue to grow. Many Canadian municipalities have no ordinances related to wind turbine placements. Consumers interested in purchasing small wind turbines should ensure that the turbine has been certified by an accredited test facility and has an adequate safety system. The noise of the turbine as well as its power performance in relation to the purchaser's needs must also be considered. It was concluded that small wind turbines can provide a means for electricity consumers to reduce their carbon footprint and hedge against the inflationary costs of fossil-fuelled energy resources. tabs., figs

Operation and control of large wind turbines and wind farms

Energy Technology Data Exchange (ETDEWEB)

Soerensen, Poul; Hansen, Anca D.; Thomsen, Kenneth (and others)

2005-09-01

This report is the final report of a Danish research project 'Operation and control of large wind turbines and wind farms'. The objective of the project has been to analyse and assess operational strategies and possibilities for control of different types of wind turbines and different wind farm concepts. The potentials of optimising the lifetime/energy production ratio by means of using revised operational strategies for the individual wind turbines are investigated. Different strategies have been simulated, where the power production is decreased to an optimum when taking loads and actual price of produced electricity into account. Dynamic models and control strategies for the wind farms have also been developed, with the aim to optimise the operation of the wind farms considering participation in power system control of power (frequency) and reactive power (voltage), maximise power production, keep good power quality and limit mechanical loads and life time consumption. The project developed models for 3 different concepts for wind farms. Two of the concepts use active stall controlled wind turbines, one with AC connection and one with modern HVDC/VSC connection of the wind farm. The third concept is based on pitch controlled wind turbines using doubly fed induction generators. The models were applied to simulate the behaviour of the wind farm control when they were connected to a strong grid, and some initial simulations were performed to study the behaviour of the wind farms when it was isolated from the main grid on a local grid. Also the possibility to use the available information from the wind turbine controllers to predict the wind speed has been investigated. The main idea has been to predict the wind speed at a wind turbine using up-wind measurements of the wind speed in another wind turbine. (au)

VisibleWind: wind profile measurements at low altitude

Science.gov (United States)

Wilkerson, Tom; Bradford, Bill; Marchant, Alan; Apedaile, Tom; Wright, Cordell

2009-09-01

VisibleWindTM is developing an inexpensive rapid response system, for accurately characterizing wind shear and small scale wind phenomena in the boundary layer and for prospecting suitable locations for wind power turbines. The ValidWind system can also collect reliable "ground truth" for other remote wind sensors. The system employs small (0.25 m dia.) lightweight balloons and a tracker consisting of an Impulse 200 XL laser rangefinder coupled to a PC for automated data recording. Experiments on balloon trajectories demonstrate that the laser detection of range (+/- 0.5 m), together with measured azimuth and altitude, is an inexpensive, convenient, and capable alternative to other wind tracking methods. The maximum detection range has been increased to 2200 meters using micro-corner-cube retroreflector tape on balloons. Low power LEDs enable nighttime tracking. To avoid large balloon gyrations about the mean trajectory, we use balloons having low ascent rates and subcritical Reynolds numbers. Trajectory points are typically recorded every 4 - 7 seconds. Atmospheric features observed under conditions of inversions or "light and variable winds" include abrupt onsets of shear at altitudes of 100-250 m, velocity changes of order 1-3 m/s within layers of 10-20 m thickness, and veering of the wind direction by 180 degrees or more as altitude increases from 300 to 500 m. We have previously reported comparisons of balloon-based wind profiles with the output of a co-located sodar. Even with the Impulse rangefinder, our system still requires a "man in the loop" to track the balloon. A future system enhancement will automate balloon tracking, so that laser returns are obtained automatically at 1 Hz. While balloon measurements of large-scale, high altitude wind profiles are well known, this novel measurement system provides high-resolution, real-time characterization of the fluctuating local wind fields at the bottom of the boundary layer where wind power turbines and other

Wind Power Meteorology

DEFF Research Database (Denmark)

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

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......: 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...

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.

Wind for Schools: A Wind Powering America Project

Science.gov (United States)

US Department of Energy, 2007

2007-01-01

The U.S. Department of Energy's (DOE's) Wind Powering America program (based at the National Renewable Energy Laboratory) sponsors the Wind for Schools Project to raise awareness in rural America about the benefits of wind energy while simultaneously educating college seniors regarding wind energy applications. The three primary project goals of…

Further analysis of PREVAIL: enzalutamide use in chemotherapy-naïve men with metastatic castration-resistant prostate cancer.

Science.gov (United States)

Aragon-Ching, Jeanny B

2014-01-01

PREVAIL was a phase III multinational, double-blind, placebo-controlled trial that enrolled chemotherapy-naïve men with metastatic castration-resistant prostate cancer (mCRPC), which showed remarkable improvement in co-primary endpoints with an overall 81% reduction in the risk of radiographic progression, as well as 29% reduction in the risk of death in favor of the enzalutamide arm over placebo. All secondary endpoints including time to subsequent chemotherapy initiation and prostate specific antigen (PSA) progression were in favor of the enzalutamide arm. The results of PREVAIL shows the utility of enzalutamide that would likely soon expand the indication to asymptomatic or minimally symptomatic men with mCRPC not previously treated with chemotherapy.

76 FR 21036 - Application of the Prevailing Wage Methodology in the H-2B Program

Science.gov (United States)

2011-04-14

... Department to ``promulgate new rules concerning the calculation of the prevailing wage rate in the H-2B... wage methodology set forth in this Rule applies only to wages paid for work performed on or after...: Notice. SUMMARY: On January 19, 2011, the Department of Labor (Department) published a final rule, Wage...

THREE-DIMENSIONAL EVOLUTION OF SOLAR WIND DURING SOLAR CYCLES 22–24

International Nuclear Information System (INIS)

Manoharan, P. K.

2012-01-01

This paper presents an analysis of three-dimensional evolution of solar wind density turbulence and speed at various levels of solar activity between solar cycles 22 and 24. The solar wind data used in this study have been obtained from the interplanetary scintillation (IPS) measurements made at the Ooty Radio Telescope, operating at 327 MHz. Results show that (1) on average, there was a downward trend in density turbulence from the maximum of cycle 22 to the deep minimum phase of cycle 23; (2) the scattering diameter of the corona around the Sun shrunk steadily toward the Sun, starting from 2003 to the smallest size at the deepest minimum, and it corresponded to a reduction of ∼50% in the density turbulence between the maximum and minimum phases of cycle 23; (3) the latitudinal distribution of the solar wind speed was significantly different between the minima of cycles 22 and 23. At the minimum phase of solar cycle 22, when the underlying solar magnetic field was simple and nearly dipole in nature, the high-speed streams were observed from the poles to ∼30° latitudes in both hemispheres. In contrast, in the long-decay phase of cycle 23, the sources of the high-speed wind at both poles, in accordance with the weak polar fields, occupied narrow latitude belts from poles to ∼60° latitudes. Moreover, in agreement with the large amplitude of the heliospheric current sheet, the low-speed wind prevailed in the low- and mid-latitude regions of the heliosphere. (4) At the transition phase between cycles 23 and 24, the high levels of density and density turbulence were observed close to the heliospheric equator and the low-speed solar wind extended from the equatorial-to-mid-latitude regions. The above results in comparison with Ulysses and other in situ measurements suggest that the source of the solar wind has changed globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has been significantly reduced

Suprathermal electron loss cone distributions in the solar wind: Ulysses observations

International Nuclear Information System (INIS)

Phillips, J. L.; Feldman, W. C.; Gosling, J. T.; Hammond, C. M.; Forsyth, R. J.

1996-01-01

We present observations by the Ulysses solar wind plasma experiment of a new class of suprathermal electron signatures. At low solar latitudes and heliocentric distances beyond 3.37 AU Ulysses encountered seven intervals, ranging in duration from 1 hour to 22 hours, in which the suprathermal distributions included an antisunward field-aligned beam and a return population with a flux dropout typically spanning ±60 deg. from the sunward field-aligned direction. All events occurred between the forward and reverse shocks or waves bounding corotating interaction regions (CIRs). The observations support a scenario in which the sunward-moving electrons result from reflection of the prevailing antisunward field-aligned beam at magnetic field compressions downstream from the spacecraft, with wide loss cones caused by the relatively weak mirror ratio. This hypothesis requires that the field magnitude within the CIRs actually increased locally with increasing field-aligned distance from the Sun

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 observati......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....

Wind Observatory 2017. Analysis of the wind power market, wind jobs and future of the wind industry in France

International Nuclear Information System (INIS)

2017-09-01

Two years after the enactment of the Energy Transition for Green Growth Act, wind power capacity continues to grow in France, exceeding 12 GWatt the end of 2016 and soon to account for 5% of France's electric power consumption. This vitality, which is set to continue in 2017, will help France achieve its objectives of an installed capacity of 15,000 MW in onshore wind by 2018 and 21,800 to 26,000 MW by 2023. The current pace will nevertheless have to be accelerated in order to reach the realistic objective of 26 GW by 2023 mentioned in the multi-annual energy plan (PPE). With 1,400 jobs created in one year and more than 3,300 over the last two years, the relevance of wind power as a driving force of sustainable job creation throughout the country is unequivocally confirmed: the increase in wind power capacity continues to contribute to the growth in employment in the country. Prepared in collaboration with the consulting firm BearingPoint, the 2017 edition of the Observatory aims to give the reader an overview of employment in the wind industry and the wind power market over the period under consideration. Any changes from the three previous editions are highlighted. It is based on a comprehensive census of all market participants on three themes: employment, the market and the future of wind power. The Observatory gives an accurate picture of how the wind energy industry is structured, thereby presenting a precise overview of the wind energy industry and all its components

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...

Simulating Wind Driven Waves in the Strait of Hormuz using MIKE21 (Simulasi Gelombang Angin di Selat Hormuz Menggunakan MIKE21

Directory of Open Access Journals (Sweden)

Faeghe Eslami Mehdiabadi

2015-03-01

Full Text Available Daerah pesisir di bumi adalah salah satu zona paling dinamis yang dipengaruhi oleh berbagai parameter seperti gelombang, arus, dan badai. Untuk mengelola serta mengkontrol zona tersebut adalah penting untuk mempelajari hidrodinamika daerah. Penelitian ini menggunakan MIKE 21/3 coupled Model FM untuk melihat gelombang (wind driven waves di sekitar Pulau Larak di Selat Hormuz. Untuk mensimulasikan pola gelombang di wilayah tersebut digunakan irregular triangular grid.  Pola arus di sekitar pulau dipelajari untuk jangka waktu satu tahun. Ditemukan bahwa gelombang yang ditimbulkan karena arus di sekitar pantai utara pulau relatif lemah. Terlihat pula bahwa gelombang yang ada di daerah tersebut terutama ke arah timur laut. Tinggi gelombang rata-rata di surfzone adalah sekitar 0,5 m., Dengan kecepatan arus sekitar 0,2 m.s-1. Mengingat angin menang dan arah gelombang, disimpulkan bahwa pantai utara Pulau Larak tempat yang cocok untuk konstruksi pelabuhan dan kegiatan memancing. Kata kunci: gelombang, arus, MIKE, Pulau Larak Coastal areas on earth are among the most dynamic zones which affected by different parameters such as waves, currents, and storms. To manage and control such a zone it is essential to study the hydrodynamic of the area. MIKE 21/3 Coupled Model FM was used to investigate the wind driven waves around Larak Island located in the Strait of Hormuz. To simulate the pattern of the wave in the area irregular triangular grid was applied. The pattern of current around the Island was studied for a one year period of simulation. It was found that the current induced wave break around the Northern coast of the Island is relatively weak. It was also observed that the prevailed wave in the area is mainly toward the Northeast. The averaged wave height in the surfzone is about 0.5 m., with the current velocity of about 0.2 m.s-1. Considering the prevailed wind and wave direction, it was concluded that the northern coasts of the Larak Island are

The Siberian High and Arctic Sea Ice: Long-term Climate Change and Impacts on Air Pollution during Wintertime in China

Science.gov (United States)

Long, X.; Zhao, S.; Feng, T.; Tie, X.; Li, G.

2017-12-01

China has undergone severe air pollution during wintertime as national industrialization and urbanization have been increasingly developed in the past three decades. It has been suggested that high emission and adverse weather patterns contribute to wintertime air pollution. Recent studies propose that climate change and Arctic sea ice loss likely lead to extreme haze events in winter. Here we use two reanalysis and observational datasets to present the trends of Siberian High (SH) intensity over Eurasia, and Arctic temperature and sea ice. The results show the Arctic region of Asia is becoming warming accompanied by a rapid decline of sea ice while Eurasia is cooling and SH intensity is gradually enhancing. Wind patterns induced by these changes cause straight westerly prevailing over Eurasia at the year of weak SH while strengthened northerly winds at the year of strong SH. Therefore, we utilize regional dynamical and chemical WRF-Chem model to determine the impact of SH intensity difference on wintertime air pollution in China. As a result, enhancing northerly winds at the year of strong SH rapidly dilute and transport air pollution, causing a decline of 50 - 400 µg m-3 PM2.5 concentrations relative to that at the year of weak SH. We also assess the impact of emission reduction to half the current level on air pollution. The results show that emission reduction by 50% has an equivalent impact as the variability of SH intensity. This suggests that climate change over Eurasia has largely offset the negative impact of emission on air pollution and it is urgently needed to take measures to mitigate air pollution. In view of current high emission scenario in China, it will be a long way to effectively mitigate, or ultimately prevent wintertime air pollution.

Meteorological controls on atmospheric particulate pollution during hazard reduction burns

Science.gov (United States)

Di Virgilio, Giovanni; Hart, Melissa Anne; Jiang, Ningbo

2018-05-01

Internationally, severe wildfires are an escalating problem likely to worsen given projected changes to climate. Hazard reduction burns (HRBs) are used to suppress wildfire occurrences, but they generate considerable emissions of atmospheric fine particulate matter, which depend upon prevailing atmospheric conditions, and can degrade air quality. Our objectives are to improve understanding of the relationships between meteorological conditions and air quality during HRBs in Sydney, Australia. We identify the primary meteorological covariates linked to high PM2.5 pollution (particulates pollution, the PBLH between 00:00 and 07:00 LT (local time) was 100-200 m higher than days with high pollution. The PBLH was similar during 10:00-17:00 LT for both low and high pollution days, but higher after 18:00 LT for HRB days with low pollution. Cloud cover, temperature and wind speed reflected the above pattern, e.g. mean temperatures and wind speeds were 2 °C cooler and 0.5 m s-1 lower during mornings and evenings of HRB days when air quality was poor. These cooler, more stable morning and evening conditions coincide with nocturnal westerly cold air drainage flows in Sydney, which are associated with reduced mixing height and vertical dispersion, leading to the build-up of PM2.5. These findings indicate that air pollution impacts may be reduced by altering the timing of HRBs by conducting them later in the morning (by a matter of hours). Our findings support location-specific forecasts of the air quality impacts of HRBs in Sydney and similar regions elsewhere.

Evaluation model of wind energy resources and utilization efficiency of wind farm

Science.gov (United States)

Ma, Jie

2018-04-01

Due to the large amount of abandoned winds in wind farms, the establishment of a wind farm evaluation model is particularly important for the future development of wind farms In this essay, consider the wind farm's wind energy situation, Wind Energy Resource Model (WERM) and Wind Energy Utilization Efficiency Model(WEUEM) are established to conduct a comprehensive assessment of the wind farm. Wind Energy Resource Model (WERM) contains average wind speed, average wind power density and turbulence intensity, which assessed wind energy resources together. Based on our model, combined with the actual measurement data of a wind farm, calculate the indicators using the model, and the results are in line with the actual situation. We can plan the future development of the wind farm based on this result. Thus, the proposed establishment approach of wind farm assessment model has application value.

Wind Turbines Adaptation to the Variability of the Wind Field

Science.gov (United States)

Ulianov, Yuriy; Martynenko, Gennadii; Misaylov, Vitaliy; Soliannikova, Iuliia

2010-05-01

WIND TURBINES ADAPTATION TO THE VARIABILITY OF THE WIND FIELD The subject of our scientific research is wind power turbines (WPT) with the horizontal axis which were now common in the world. Efficient wind turbines work is largely determined by non-stationarity of the wind field, expressed in its gustiness, the presence of vertical and horizontal shifts of wind speed and direction. At critical values of the wind parameters WPT has aerodynamic and mechanical overload, leading to breakdowns, premature wear and reduce the life of the wind turbine. To prevent accidents at the peak values of wind speed it is used the regulatory system of windwheels. WPT control systems provide a process orientation of the wind turbine rotor axis in the line of the mean wind. Wind turbines are also equipped with braking device used to protect against breakdowns when a significant increase in the wind. In general, all these methods of regulation are not always effective. Thus, in practice there may be situations when the wind speed is many times greater than the stated limit. For example, if there are microbursts in the atmospheric boundary layer, low-level wind shears caused by its gust front, storms, etc. It is required for a wind power turbine adaptation to intensive short-term wind impulses and considerable vertical wind shifts that the data about them shall be obtained ahead of time. To do this it is necessary to have the information on the real structure of the wind field in the area of the blade sweep for the minimum range against the wind that is determined by the mean speed and the system action time. The implementation of acoustic and laser traditional wind sounding systems is limited by ambient acoustic noise, by heavy rain, snowfall and by fog. There are free of these disadvantages the inclined radioacoustic sounding (IRASS) technique which works for a system of remote detection and control of wind gusts. IRASS technique is realized as low-potential Doppler pulse radar

Real time analysis for atmospheric dispersions for Fukushima nuclear accident: Mobile phone based cloud computing assessment

International Nuclear Information System (INIS)

Woo, Tae Ho

2014-01-01

Highlights: • Possible nuclear accident is simulated for the atmospheric contaminations. • The simulations results give the relative importance of the fallouts. • The cloud computing of IT is performed successfully. • One can prepare for the possible damages of such a NPP accident. • Some other variables can be considered in the modeling. - Abstract: The radioactive material dispersion is investigated by the system dynamics (SD) method. The non-linear complex algorithm could give the information about the hazardous material behavior in the case of nuclear accident. The prevailing westerlies region is modeled for the dynamical consequences of the Fukushima nuclear accident. The event sequence shows the scenario from earthquake to dispersion of the radionuclides. Then, the dispersion reaches two cities in Korea. The importance of the radioactive dispersion is related to the fast and reliable data processing, which could be accomplished by cloud computing concept. The values of multiplications for the wind, plume concentrations, and cloud computing factor are obtained. The highest value is 94.13 in the 206th day for Seoul. In Pusan, the highest value is 15.48 in the 219th day. The source is obtained as dispersion of radionuclide multiplied by 100. The real time safety assessment is accomplished by mobile phone

Equatorial atmospheric Kelvin waves during El Niño episodes and their effect on stratospheric QBO

International Nuclear Information System (INIS)

Das, Uma; Pan, C.J.

2016-01-01

Equatorial atmospheric Kelvin waves are investigated during a positive El Niño Southern Oscillation (ENSO) episode using temperature data retrieved from GPS Radio Occultation (RO) observations of FORMOSAT-3/COSMIC during the period from August 2006 to December 2013. Enhanced Kelvin wave amplitudes are observed during the El Niño episode of 2009–2010 and it is also observed that these amplitudes correlate with the Niño 3.4 index and also with outgoing longwave radiation and trade wind index. This study indicates that the enhanced equatorial atmospheric Kelvin wave amplitudes might be produced by geophysical processes that were involved in the onset and development of the El Niño episode. Further, easterly winds above the tropopause during this period favored the vertically upward propagation of these waves that induced a fast descending westerly regime by the end of 2010, where the zero-wind line is observed to take only 5 months to descend from 10 to 50 hPa. The current study presents observational evidence of enhanced Kelvin wave amplitudes during El Niño that has affected the stratospheric quasi-biennial oscillation (QBO) through wave–mean flow interactions. Earlier El Niño episodes of 1987 and 1998 are also qualitatively investigated, using reanalysis data. It is found that there might have been an enhancement in the equatorial Kelvin wave amplitudes during almost all El Niño episodes, however, an effect of a fast descending westerly is observed in the QBO only when the ambient zonal winds in the lower stratosphere favor the upward propagation of the Kelvin waves and consequently they interact with the mean flow. This study indicates that the El Niño and QBO are not linearly related and wave mean flow interactions play a very important role in connecting these two geophysical phenomena. - Highlights: • Enhanced atmospheric Kelvin Wave amplitudes observed during El Nino of 2010. • The waves are probably produced by processes generating El Nino. �

Equatorial atmospheric Kelvin waves during El Niño episodes and their effect on stratospheric QBO

Energy Technology Data Exchange (ETDEWEB)

Das, Uma [Department of Physics, University of New Brunswick, Fredericton (Canada); Pan, C.J., E-mail: cjpan@jupiter.ss.ncu.edu.tw [Institute of Space Science, National Central University, Jhongli, Taiwan (China)

2016-02-15

Equatorial atmospheric Kelvin waves are investigated during a positive El Niño Southern Oscillation (ENSO) episode using temperature data retrieved from GPS Radio Occultation (RO) observations of FORMOSAT-3/COSMIC during the period from August 2006 to December 2013. Enhanced Kelvin wave amplitudes are observed during the El Niño episode of 2009–2010 and it is also observed that these amplitudes correlate with the Niño 3.4 index and also with outgoing longwave radiation and trade wind index. This study indicates that the enhanced equatorial atmospheric Kelvin wave amplitudes might be produced by geophysical processes that were involved in the onset and development of the El Niño episode. Further, easterly winds above the tropopause during this period favored the vertically upward propagation of these waves that induced a fast descending westerly regime by the end of 2010, where the zero-wind line is observed to take only 5 months to descend from 10 to 50 hPa. The current study presents observational evidence of enhanced Kelvin wave amplitudes during El Niño that has affected the stratospheric quasi-biennial oscillation (QBO) through wave–mean flow interactions. Earlier El Niño episodes of 1987 and 1998 are also qualitatively investigated, using reanalysis data. It is found that there might have been an enhancement in the equatorial Kelvin wave amplitudes during almost all El Niño episodes, however, an effect of a fast descending westerly is observed in the QBO only when the ambient zonal winds in the lower stratosphere favor the upward propagation of the Kelvin waves and consequently they interact with the mean flow. This study indicates that the El Niño and QBO are not linearly related and wave mean flow interactions play a very important role in connecting these two geophysical phenomena. - Highlights: • Enhanced atmospheric Kelvin Wave amplitudes observed during El Nino of 2010. • The waves are probably produced by processes generating El Nino. �

Meteorological features associated with unprecedented precipitation over India during 1st week of March 2015

Science.gov (United States)

Kumar, Naresh; Mohapatra, M.; Jaswal, A. K.

2017-07-01

Unprecedented precipitation along with heavy falls occurred over many parts of India from 28th February to 2nd March 2015. Many of the stations of northwest and central India received an all time high 24 hr cumulative precipitation of March during this period. Even the national capital, New Delhi, broke all the previous historical 24 hr rainfall records of the last 100 years to the rainfall record in March 2015. Due to this event, huge loss to agricultural and horticultural crops occurred in several parts of India. In the present study, an attempt is made to understand the various meteorological features associated with this unprecedented precipitation event over India. It occurred due to the presence of an intense western disturbance (WD) over Afghanistan and neighbouring areas in the form of north-south oriented deep trough in westerlies in middle and upper tropospheric levels with its southern end deep in the Arabian Sea, which pumped huge moisture feed over Indian region. Also, there was a jet stream with core wind speed up to 160 knots that generated high positive divergence at upper tropospheric level over Indian region; along with this there was high magnitude of negative vertical velocity and velocity convergence were there at middle tropospheric level. It caused intense upward motion and forced lower levels air to rise and strengthen the lower levels cyclonic circulations (CCs)/Lows. Moreover, the induced CCs/Lows at lower tropospheric levels associated with WD were more towards south of its normal position. Additionally, there was wind confluence over central parts of India due to westerlies in association with WD and easterlies from anticyclone over north Bay of Bengal. Thus, intense WD along with wind confluence between westerlies and easterlies caused unprecedented precipitation over India during the 1st week of March 2015.

Sub-seasonal prediction of significant wave heights over the Western Pacific and Indian Oceans, part II: The impact of ENSO and MJO

Science.gov (United States)

Shukla, Ravi P.; Kinter, James L.; Shin, Chul-Su

2018-03-01

This study evaluates the effect of El Niño and the Southern Oscillation (ENSO) and Madden Julian Oscillation (MJO) events on 14-day mean significant wave height (SWH) at 3 weeks lead time (Wk34) over the Western Pacific and Indian Oceans using the National Centers for Environmental Prediction (NCEP) Climate Forecast System, version 2 (CFSv2). The WAVEWATCH-3 (WW3) model is forced with daily 10m-winds predicted by a modified version of CFSv2 that is initialized with multiple ocean analyses in both January and May for 1979-2008. A significant anomaly correlation of predicted and observed SWH anomalies (SWHA) at Wk34 lead-time is found over portions of the domain, including the central western Pacific, South China Sea (SCS), Bay of Bengal (BOB) and southern Indian Ocean (IO) in January cases, and over BOB, equatorial western Pacific, the Maritime Continent and southern IO in May cases. The model successfully predicts almost all the important features of the observed composite SWHA during El Niño events in January, including negative SWHA in the central IO where westerly wind anomalies act on an easterly mean state, and positive SWHA over the southern Ocean (SO) where westerly wind anomalies act on a westerly mean state. The model successfully predicts the sign and magnitude of SWHA at Wk34 lead-time in May over the BOB and SCS in composites of combined phases-2-3 and phases-6-7 of MJO. The observed leading mode of SWHA in May and the third mode of SWHA in January are influenced by the combined effects of ENSO and MJO. Based on spatial and temporal correlations, the spatial patterns of SWHA in the model at Wk34 in both January and May are in good agreement with the observations over the equatorial western Pacific, equatorial and southern IO, and SO.

Investigation of Wind Turbine Rotor Concepts for Offshore Wind Farms

International Nuclear Information System (INIS)

Ceyhan, Özlem; Grasso, Francesco

2014-01-01

Current plans in offshore wind energy developments call for further reduction of cost of energy. In order to contribute to this goal, several wind turbine rotor concepts have been investigated. Assuming the future offshore wind turbines will operate only in the offshore wind farms, the rotor concepts are not only evaluated for their stand-alone performances and their potential in reducing the loads, but also for their performance in an offshore wind farm. In order to do that, the 10MW reference wind turbine designed in Innwind.EU project is chosen as baseline. Several rotor parameters have been modified and their influences are investigated for offshore wind turbine design purposes. This investigation is carried out as a conceptual parametrical study. All concepts are evaluated numerically with BOT (Blade optimisation tool) software in wind turbine level and with Farmflow software in wind farm level for two wind farm layouts. At the end, all these concepts are compared with each other in terms of their advantages and disadvantages

Wind of opportunity

International Nuclear Information System (INIS)

Jamieson, Peter

1999-01-01

This article traces the move towards the offshore exploitation of wind energy in Europe, and presents information on existing offshore wind energy projects and proposed wind turbine prototypes for offshore operation. The building of the first major offshore wind project at Vindeby, the use of rock socketed monopile foundations for pile drilling and erection of the wind turbines from a mobile jack-up barge, the costs of wind turbines, the fatigue loads on the support structures due to the wind loading, and the offshore wind market in the UK and Europe are discussed. (UK)

White Sands Missile Range 2007 Urban Study: Data Processing - Volume DP-1 (Sonic Calibration)

Science.gov (United States)

2008-09-01

calibrated in a wind tunnel against a NIST standard were positioned at the two ends of the lineup , closest to the buildings (positions 1 and 10 in...utilized westerly winds between 8 and 10 m/s (2007 February 24, 0600–0605 LT). The 5 min of data utilized by the “fast” case were sequential . The...2.4–11.2 m/s. The 5-min “variable” case utilized sequential minutes. Results from all three WS conditions were the following (Vaucher, 2007a

Wind Atlas of Bay of Bengal with Satellite Wind Measurement

DEFF Research Database (Denmark)

Nadi, Navila Rahman

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......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......) 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...

The influence of several changes in atmospheric states over semi-arid areas on the incidence of mental health disorders

Science.gov (United States)

Yackerson, Naomy S.; Zilberman, Arkadi; Todder, Doron; Kaplan, Zeev

2011-05-01

The incidence of suicide attempts [Deliberate Self Harm (DSH); ICD-10: X60-X84] and psychotic attacks (PsA; ICD-10, F20-F29) in association with atmospheric states, typical for areas close to big deserts, was analyzed. A retrospective study is based on the 4,325 cases of DSH and PsA registered in the Mental Health Center (MHC) of Ben-Gurion University (Be'er-Sheva, Israel) during 2001-2003. Pearson and Spearman test correlations were used; the statistical significance was tested at p 0.1). Correlation coefficients between N SU and N PS and speed WS of westerly wind reaches 0.3 ( p 0.09). Variations in easterly wind direction WD influence N SU and N PS values ( p 0.3). Obviously ,in transition areas located between different regions ,the main role of air streams in meteorological-biological impact can scarcely be exaggerated. An unstable balance in the internal state of a weather-sensitive person is disturbed when the atmospheric state is changed by specific desert winds, which can provoke significant perturbations in meteorological parameters. Results indicate the importance of wind direction, defining mainly the atmospheric situation in semi-arid areas: changes in direction of the easterly wind influence N SU and N PS , while changes in WS are important for mental health under westerly air streams. Obviously, N SU and N PS are more affected by the disturbance of weather from its normal state, for a given season, to which the local population is accustomed, than by absolute values of meteorological parameters.

Wind Tunnel Tests for Wind Pressure Distribution on Gable Roof Buildings

Science.gov (United States)

2013-01-01

Gable roof buildings are widely used in industrial buildings. Based on wind tunnel tests with rigid models, wind pressure distributions on gable roof buildings with different aspect ratios were measured simultaneously. Some characteristics of the measured wind pressure field on the surfaces of the models were analyzed, including mean wind pressure, fluctuating wind pressure, peak negative wind pressure, and characteristics of proper orthogonal decomposition results of the measured wind pressure field. The results show that extremely high local suctions often occur in the leading edges of longitudinal wall and windward roof, roof corner, and roof ridge which are the severe damaged locations under strong wind. The aspect ratio of building has a certain effect on the mean wind pressure coefficients, and the effect relates to wind attack angle. Compared with experimental results, the region division of roof corner and roof ridge from AIJ2004 is more reasonable than those from CECS102:2002 and MBMA2006.The contributions of the first several eigenvectors to the overall wind pressure distributions become much bigger. The investigation can offer some basic understanding for estimating wind load distribution on gable roof buildings and facilitate wind-resistant design of cladding components and their connections considering wind load path. PMID:24082851

The application of hydraulics in the 2,000 kW wind turbine generator

Science.gov (United States)

Onufreiczuk, S.

1978-01-01

A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

Effects of offshore wind farms on marine wildlife—a generalized impact assessment

International Nuclear Information System (INIS)

Bergström, Lena; Kautsky, Lena; Malm, Torleif; Åstrand Capetillo, Nastassja; Rosenberg, Rutger; Wahlberg, Magnus; Wilhelmsson, Dan

2014-01-01

Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning. (paper)

A study of the integration of wind energy into the national energy systems of Denmark, Wales and Germany as illustrations of success stories for renewable energy

International Nuclear Information System (INIS)

Lindley, D.

1996-01-01

Of the approximately 2400 MW of wind turbines now installed in Europe, about 1850 MW are operational or under construction in Germany, Denmark and Wales. The rate of installation in the last three years and current developments in these three countries suggest that this implementation will continue until the end of the century at the rate of about 400 MW per annum. Clearly, wind energy is one of renewable energy's major success stories and it is the purpose of this study to attempt to identify the reasons for this success. By analysing the different conditions that have prevailed in the three European countries where implementation has been the greatest, the study seeks to identify the circumstances which need to be created in other countries and for other renewable energy technologies in order to accelerate their integration into the energy systems of Europe. (author)

Economics of a small wind pump system based on estimated petrol and diesel cost savings from use in Northern Nigeria

Directory of Open Access Journals (Sweden)

C. J. Ejieji

2013-08-01

Full Text Available Eleven years of daily wind records were analyzed for the estimation of available wind energy for water pumping at three selected locations in Northern Nigeria, namely Jos, Kano and Sokoto. This formed the basis for investigating the economics of the use of an imported small wind pump under a deregulated energy market environment. The estimated available energy for water pumping at the installation height of 9m was 190 kwh/m2/yr for Jos, 225 kwh/m2/yr for Kano and 348 kwh/m2/yr for Sokoto. The monetary value of the available wind energy was considered as saved energy cost. The saved cost was obtained in terms of the unsubsidized cost of the petrol and diesel that an internal combustion engine (ICE would consume to produce energy equivalent to the available wind energy. At the prevailing interest and inflation rates of 21.96 % and 12.1% respectively, and unsubsidized prices of N 131.32/l and N 140.23/l for petrol and diesel respectively, investment in the wind pump was not found to be economically competitive relative to using a pump with ICE prime mover at the three locations unless the cost of the pump was subsidized. For Sokoto, the estimated subsidy for initial cost of the wind pump required for the investment to be competitive relative to the use of a pump driven by a petrol ICE was 16%. Relative to a pump driven by a diesel ICE, the required subsidy was 24%. The corresponding subsidy estimates for Kano were 48 % and 51 % respectively. For Jos, it was 56% relative to the use of a pump driven by a petrol ICE and 60 % relative to that driven by a diesel ICE. Considering the potential environmental and social and environmental benefits however, subsidy support by government for local manufacturing of the pumps was recommended since shipping cost and custom tariff constituted over 36% of the initial cost of the wind pump.

A 27 ka paleoenvironmental lake sediment record from Taro Co, central Tibetan Plateau: implications for the interplay between monsoon and the Westerlies

Science.gov (United States)

Wang, J.; Ma, Q.; Huang, L.; Ju, J.; Guo, Y.; Lin, X.; Li, Y.; Zhu, L.

2017-12-01

The climate of Tibetan Plateau (TP) is mainly influenced by the Indian Ocean Summer Monsoon (IOSM) and the Westerlies. The interaction of these two air masses is therefore a crucial scientific issue to understand how they impact the climate in this area, especially in the geological times. However, constrained by the available archives, researches on this topic are still very few in the hinterland of the TP, especially covering the Last Glacial Maximum (LGM) period. Here we present a new lake sediment record retrieved from Taro Co covering the last 27 ka to elucidate how the IOSM and the Westerlies interact and the possible mechanisms. Taro Co (486 km2, Dmax: 132m, 4565 m a.s.l., currently closed), located on the central TP, is a fresh lake with the major supply from glaciers. Two parallel piston cores as well as several gravity cores were retrieved from the deepest parts. These cores were correlated based on high resolution XRF scanning and a continuous 1069 cm-long core was finally integrated. Chronology was determined by 210Pb, 137Cs and AMS 14C measurements. Multidiscipline analyses including grain size, total organic carbon (TOC), total nitrogen, diatom, ostracod, pollen and n-alkanes were accomplished to reconstruct paleoenvironmental changes. The lake level of Taro Co was low since 27 cal ka BP indicated by very coarse materials and diatom assemblages with gradually increased temperature and salinity (TOC and carbonate getting higher). The terrestrial water input decreased continuously reflected by such elements as Si, Ti, Fe, K. It is likely that there was a sedimentation gap between 961-954cm, corresponding to 23.4 to 18.6 cal ka BP probably demonstrated Taro Co was very shallow at that period. The first prominent abrupt change of most proxies was observed at 14.7 cal ka BP showing a great lake deepening which likely indicated an enhancement of IOSM. There were several spells with abrupt changes of cold/warm stages before the Holocene and the Younger Dryas

Wind Loads on Structures

DEFF Research Database (Denmark)

Dyrbye, Claes; Hansen, Svend Ole

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...... 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...... induced by wind turbulence, vortex shedding, flutter and galloping. The book gives a comprehensive treatment of wind effects on structures and it will be useful for consulting engineers designing wind-sensitive structures. It will also be valuable for students of civil engineering as textbook...

A simple method to downscale daily wind statistics to hourly wind data

OpenAIRE

Guo, Zhongling

2013-01-01

Wind is the principal driver in the wind erosion models. The hourly wind speed data were generally required for precisely wind erosion modeling. In this study, a simple method to generate hourly wind speed data from daily wind statistics (daily average and maximum wind speeds together or daily average wind speed only) was established. A typical windy location with 3285 days (9 years) measured hourly wind speed data were used to validate the downscaling method. The results showed that the over...

Variability of sediment transport in beach and coastal dune environments, Brittany, France

Science.gov (United States)

Regnauld, Hervé; Louboutin, Roland

2002-06-01

On the coasts of Brittany (English Channel and Bay of Biscay), barrier systems were surveyed between 1995 and 2000. The beach profiles have a very high variability, which cannot be statistically explained by linear correlation with the wind, the waves, or the tides. The behaviour of the profile is represented on a phase diagram (speed of profile change: Y-axis, thickness of the profile: X-axis). The points in the center of the profile "rotate" around an average equilibrium which is seldom measured in the field. The seaward edge of the beaches oscillates between loss and gain, but with a net positive budget. The landward top of the beach displays a range of oscillations. The dunes always have a positive budget. The whole behaviour of the system is explained if the precise succession of anticyclonic and cyclonic winds is taken into account. Long periods of easterly winds (offshorewards) tend to produce a calm sea and to increase tidal sediment settling on the seafloor. If an onshore westerly storm occurs just after such a period, it hits a sediment-rich environment and produces a net accumulation on both the beach and the dunes. Periods of westerly calm to moderate winds do not help accumulation: a full going storm will hit a depleted environment and produce erosion. The speed of dune accretion and the budget of the beaches seem to partly depend on the ratio of cyclonic to anticyclonic conditions.

Cost optimization of wind turbines for large-scale offshore wind farms

International Nuclear Information System (INIS)

Fuglsang, P.; Thomsen, K.

1998-02-01

This report contains a preliminary investigation of site specific design of off-shore wind turbines for a large off-shore wind farm project at Roedsand that is currently being proposed by ELKRAFT/SEAS. The results were found using a design tool for wind turbines that involve numerical optimization and aeroelastic calculations of response. The wind climate was modeled in detail and a cost function was used to estimate costs from manufacture and installation. Cost of energy is higher for off-shore installations. A comparison of an off-shore wind farm site with a typical stand alone on-shore site showed an increase of the annual production of 28% due to the difference in wind climate. Extreme loads and blade fatigue loads were nearly identical, however,fatigue loads on other main components increased significantly. Optimizations were carried out to find the optimum overall off-shore wind turbine design. A wind turbine for the off-shore wind farm should be different compared with a stand-alone on-shore wind turbine. The overall design changed were increased swept area and rated power combined with reduced rotor speed and tower height. Cost was reduced by 12% for the final 5D/14D off-shore wind turbine from 0.306 DKr/kWh to 0.270 DKr/kWh. These figures include capital costs from manufacture and installation but not on-going costs from maintenance. These results make off-shore wind farms more competitive and comparable to the reference on-shore stand-alone wind turbine. A corresponding reduction of cost of energy could not be found for the stand alone on-shore wind turbine. Furthermore the fatigue loads on wind turbines in on-shore wind farms will increase and cost of energy will increase in favor of off-shore wind farms. (au) EFP-95; EU-JOULE-3; 21 tabs., 7 ills., 8 refs

Dust fluxes linked to intensification of Prevailing Westerlies and Trade Winds stimulated Ethmodiscus rex giant diatom blooms in the southern Mariana Trench, western tropical Pacific at onset of the Last Glacial Maximum

Science.gov (United States)

Chen, D.; Luo, M.; Algeo, T. J.; Chen, L.

2017-12-01

The strontium (Sr) and neodymium (Nd) isotope compositions and clay-mineral assemblages of the detrital fraction of sediments in the southern Mariana Trench together with major- and trace-elements concentrations of bulk sediments have been determined to trace the sediment provenance and investigate the relationship between Asian dust input and blooms of the giant diatom Ethmodiscus rex. Enrichment of barium (Ba) in relative to upper continental crust (UCC) and low average Rb/K ratios in all study cores point to both hydrothermal and volcaniclastic inputs to the sediments. Both the Sr-Nd isotope compositions and the clay-mineral assemblages of the detrital fraction reflect a two-component mixing system consisting of Mariana arc volcaniclastics and eolian Asian dust. A decrease in smectite content and an increase in illite content just before formation of laminated diatom mats (LDMs) suggest a change in the source of the eolian dust from eastern Asian deserts (EADs) to central Asian deserts (CADs) at the onset of the Last Glacial Maximum (LGM). This observation suggests a causal linkage between atmospheric circulation patterns, the sources of eolian Asian dust, and marine productivity in the western Pacific region. We postulate that the shift to CAD-sourced dust may have played a greater role in promoting biological productivity in the oligotrophic western Pacific Ocean during the LGM than previously realized.

Damping Wind and Wave Loads on a Floating Wind Turbine

DEFF Research Database (Denmark)

Christiansen, Søren; Bak, Thomas; Knudsen, Torben

2013-01-01

Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. To enable deployment of wind turbines in deep-water locations, structures are being explored, where wind turbines are placed on a floating platform. This combined structure presents a new control problem, due......, and we show the influence that both wind speed, wave frequencies and misalignment between wind and waves have on the system dynamics. A new control model is derived that extends standard turbine models to include the hydrodynamics, additional platform degrees of freedom, the platform mooring system...

Analysis of complex wind regimes at Kennedy Space Center for radiological assessment

International Nuclear Information System (INIS)

Taylor, G.E.; Parks, C.R.; Atchison, M.K.

1989-01-01

Galileo and Ulysses will be launched from the Kennedy Space Center (KSC) during October 1989 and October 1990, respectively. These deep-space probes will contain a radioactive thermoelectric generator as a power source. An accidental breach of the containment vessel housing the generator could cause a leak of radioactive material to the atmosphere. If this occurred, the radioactive cloud would move with the prevailing wind flow pattern and pose a serious health threat to all in its path. Since the KSC/Cape Canaveral (KSC/CC) area of Florida is located in a coastal environment with several different land/water interfaces, complex low-level wind circulation patterns exist throughout the year. Thus, if any transport and diffusion model is to correctly predict the movement of effluent near KSC, it must be able to accurately portray the characteristics of the land/sea breeze flow pattern. To evaluate models used at KSC, the KSC Atmospheric Boundary Layer Experiment (KABLE) has been designed to provide a data set to better define the characteristics of these mesoscale circulations. Data collection for KABLE occurred from November 1, 1988, to October 31, 1989. This paper presents analyses for 1 day during November 1988 that demonstrate the complexity of the local meteorological conditions at KSC/CC. The NUS Corporation has used these data and empirical sea breeze parameters to evaluate their Emergency Dose Assessment System, EMERGE

Calculation of depleted wind resources near wind farms

DEFF Research Database (Denmark)

Nielsen, Morten

2015-01-01

Traditional wind resource maps include wind distribution, energy density and potential power production without wake effects. Adding wake effect to such maps is feasible by means of a new method based on Fourier transformation,and the extra computational work is comparable to that of the basic wind...

Wind-driven snow conditions control the occurrence of contemporary marginal mountain permafrost in the Chic-Choc Mountains, south-eastern Canada: a case study from Mont Jacques-Cartier

Science.gov (United States)

Davesne, Gautier; Fortier, Daniel; Domine, Florent; Gray, James T.

2017-06-01

We present data on the distribution and thermophysical properties of snow collected sporadically over 4 decades along with recent data of ground surface temperature from Mont Jacques-Cartier (1268 m a.s.l.), the highest summit in the Appalachians of south-eastern Canada. We demonstrate that the occurrence of contemporary permafrost is necessarily associated with a very thin and wind-packed winter snow cover which brings local azonal topo-climatic conditions on the dome-shaped summit. The aims of this study were (i) to understand the snow distribution pattern and snow thermophysical properties on the Mont Jacques-Cartier summit and (ii) to investigate the impact of snow on the spatial distribution of the ground surface temperature (GST) using temperature sensors deployed over the summit. Results showed that above the local treeline, the summit is characterized by a snow cover typically less than 30 cm thick which is explained by the strong westerly winds interacting with the local surface roughness created by the physiography and surficial geomorphology of the site. The snowpack structure is fairly similar to that observed on windy Arctic tundra with a top dense wind slab (300 to 450 kg m-3) of high thermal conductivity, which facilitates heat transfer between the ground surface and the atmosphere. The mean annual ground surface temperature (MAGST) below this thin and wind-packed snow cover was about -1 °C in 2013 and 2014, for the higher, exposed, blockfield-covered sector of the summit characterized by a sporadic herbaceous cover. In contrast, for the gentle slopes covered with stunted spruce (krummholz), and for the steep leeward slope to the south-east of the summit, the MAGST was around 3 °C in 2013 and 2014. The study concludes that the permafrost on Mont Jacques-Cartier, most widely in the Chic-Choc Mountains and by extension in the southern highest summits of the Appalachians, is therefore likely limited to the barren wind-exposed surface of the summit

Post hoc analysis of Japanese patients from the placebo-controlled PREVAIL trial of enzalutamide in patients with chemotherapy-naive, metastatic castration-resistant prostate cancer—updated results

Science.gov (United States)

Ueda, Takeshi

2017-01-01

Abstract A post hoc analysis of interim results from PREVAIL, a Phase III, double-blind, placebo-controlled trial of men with metastatic castration-resistant prostate cancer, demonstrated that the treatment effects, safety and pharmacokinetics of enzalutamide in Japanese patients were generally consistent with those of the overall population. A recent longer term analysis of PREVAIL demonstrated continued benefit of enzalutamide treatment over placebo. Here, we report results from a post hoc analysis of Japanese patients enrolled in PREVAIL at the prespecified number of deaths for the final analysis. In Japanese patients, enzalutamide reduced the risk of death by 35% (hazard ratio, 0.65; 95% confidence interval, 0.28–1.51) and the risk of investigator-assessed radiographic progression or death by 60% (hazard ratio, 0.40; 95% confidence interval, 0.18–0.90). These results show that treatment effects and safety in Japanese patients in the final analysis of PREVAIL continued to be generally consistent with those of the overall population. PMID:28003320

Climatic wind tunnel for wind engineering tasks

Czech Academy of Sciences Publication Activity Database

Kuznetsov, Sergeii; Pospíšil, Stanislav; Král, Radomil

2015-01-01

Roč. 112, 2-B (2015), s. 303-316 ISSN 1897-628X R&D Projects: GA ČR(CZ) GA14-12892S Keywords : climatic tunnel * wind tunnel * atmospheric boundary layer * flow resistance * wind tunnel contraction Subject RIV: JM - Building Engineering https://suw.biblos.pk.edu.pl/resources/i5/i6/i6/i7/i6/r56676/KuznetsovS_ClimaticWind.pdf

Progress in wind tunnel experimental techniques for wind turbine?

Institute of Scientific and Technical Information of China (English)

Jingping XIAO; Li CHEN; Qiang WANG; Qiao WANG

2016-01-01

Based on the unsteady aerodynamics experiment (UAE) phase VI and the model experiment in controlled conditions (MEXICO) projects and the related research carried out in China Aerodynamic Research and Development Center (CARDC), the recent progress in the wind tunnel experimental techniques for the wind turbine is sum-marized. Measurement techniques commonly used for di?erent types of wind tunnel ex-periments for wind turbine are reviewed. Important research achievements are discussed, such as the wind tunnel disturbance, the equivalence of the airfoil in?ow condition, the three-dimensional (3D) e?ect, the dynamic in?ow in?uence, the ?ow ?eld structure, and the vortex induction. The corresponding research at CARDC and some ideas on the large wind turbine are also introduced.

3D WindScanner lidar measurements of wind and turbulence around wind turbines, buildings and bridges

DEFF Research Database (Denmark)

Mikkelsen, Torben Krogh; Sjöholm, Mikael; Angelou, Nikolas

2017-01-01

WindScanner is a distributed research infrastructure developed at DTU with the participation of a number of European countries. The research infrastructure consists of a mobile technically advanced facility for remote measurement of wind and turbulence in 3D. The WindScanners provide coordinated...... structures and of flow in urban environments. The mobile WindScanner facility enables 3D scanning of wind and turbulence fields in full scale within the atmospheric boundary layer at ranges from 10 meters to 5 (10) kilometers. Measurements of turbulent coherent structures are applied for investigation...

Enzalutamide in Men with Chemotherapy-naïve Metastatic Castration-resistant Prostate Cancer: Extended Analysis of the Phase 3 PREVAIL Study.

Science.gov (United States)

Beer, Tomasz M; Armstrong, Andrew J; Rathkopf, Dana; Loriot, Yohann; Sternberg, Cora N; Higano, Celestia S; Iversen, Peter; Evans, Christopher P; Kim, Choung-Soo; Kimura, Go; Miller, Kurt; Saad, Fred; Bjartell, Anders S; Borre, Michael; Mulders, Peter; Tammela, Teuvo L; Parli, Teresa; Sari, Suha; van Os, Steve; Theeuwes, Ad; Tombal, Bertrand

2017-02-01

Enzalutamide significantly improved radiographic progression-free survival (rPFS) and overall survival (OS) among men with chemotherapy-naïve metastatic castration-resistant prostate cancer at the prespecified interim analysis of PREVAIL, a phase 3, double-blind, randomized study. We evaluated the longer-term efficacy and safety of enzalutamide up to the prespecified number of deaths in the final analysis, which included an additional 20 mo of follow-up for investigator-assessed rPFS, 9 mo of follow-up for OS, and 4 mo of follow-up for safety. Enzalutamide reduced the risk of radiographic progression or death by 68% (hazard ratio [HR] 0.32, 95% confidence interval [CI] 0.28-0.37; pPREVAIL provides more complete assessment of the clinical benefit of enzalutamide. PREVAIL is registered on ClinicalTrials.gov as NCT01212991. According to data from longer follow-up, enzalutamide continued to provide benefit over placebo in patients with metastatic castration-resistant prostate cancer. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Wind Turbine Generator System Acoustic Noise Test Report for the Gaia Wind 11-kW Wind Turbine

Energy Technology Data Exchange (ETDEWEB)

Huskey, A.

2011-11-01

This report details the acoustic noise test conducted on the Gaia-Wind 11-kW wind turbine at the National Wind Technology Center. The test turbine is a two- bladed, downwind wind turbine with a rated power of 11 kW. The test turbine was tested in accordance with the International Electrotechnical Commission standard, IEC 61400-11 Ed 2.1 2006-11 Wind Turbine Generator Systems -- Part 11 Acoustic Noise Measurement Techniques.

Cooperative wind turbine control for maximizing wind farm power using sequential convex programming

International Nuclear Information System (INIS)

Park, Jinkyoo; Law, Kincho H.

2015-01-01

Highlights: • The continuous wake model describes well the wake profile behind a wind turbine. • The wind farm power function describes well the power production of a wind farm. • Cooperative control increases the wind farm power efficiency by 7.3% in average. • SCP can be employed to efficiently optimize the control actions of wind turbines. - Abstract: This paper describes the use of a cooperative wind farm control approach to improve the power production of a wind farm. The power production by a downstream wind turbine can decrease significantly due to reduced wind speed caused by the upstream wind turbines, thereby lowering the overall wind farm power production efficiency. In spite of the interactions among the wind turbines, the conventional (greedy) wind turbine control strategy tries to maximize the power of each individual wind turbine by controlling its yaw angle, its blade pitch angle and its generator torque. To maximize the overall wind farm power production while taking the wake interference into account, this study employs a cooperative control strategy. We first derive the wind farm power as a differentiable function of the control actions for the wind turbines in a wind farm. The wind farm power function is then maximized using sequential convex programming (SCP) to determine the optimum coordinated control actions for the wind turbines. Using an example wind farm site and available wind data, we show how the cooperative control strategy improves the power production of the wind farm

Monthly Wind Characteristics and Wind Energy in Rwanda

African Journals Online (AJOL)

user

Abstract. Evaluating wind power potential for a site is indispensable before making any decision for the installation of wind energy infrastructures and planning for relating projects. This paper presents a branch of a composite analysis whose objective was to investigate the potential of wind energy resource in Rwanda.

IEA Wind Task 26: Offshore Wind Farm Baseline Documentation

Energy Technology Data Exchange (ETDEWEB)

Smart, Gavin [Offshore Renewable Energy Catapult, Blyth, Northumberland (United Kingdom); Smith, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Warner, Ethan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sperstad, Iver Bakken [SINTEF Energy Research, Trondheim (Norway); Prinsen, Bob [Ecofys, Utrecht (Netherlands). TKI Wind Op Zee; Lacal-Arantegui, Roberto [European Commission Joint Research Centre (JRC), Brussels (Belgium)

2016-06-02

This document has been produced to provide the definition and rationale for the Baseline Offshore Wind Farm established within IEA Wind Task 26--Cost of Wind Energy. The Baseline has been developed to provide a common starting point for country comparisons and sensitivity analysis on key offshore wind cost and value drivers. The baseline project reflects an approximate average of the characteristics of projects installed between 2012 and 2014, with the project life assumed to be 20 years. The baseline wind farm is located 40 kilometres (km) from construction and operations and maintenance (O&M) ports and from export cable landfall. The wind farm consists of 100 4-megawatt (MW) wind turbines mounted on monopile foundations in an average water depth of 25 metres (m), connected by 33-kilovolt (kV) inter-array cables. The arrays are connected to a single offshore substation (33kV/220kV) mounted on a jacket foundation, with the substation connected via a single 220kV export cable to an onshore substation, 10km from landfall. The wind farm employs a port-based O&M strategy using crew-transfer vessels.

Modeling wind speed and wind power distributions in Rwanda

Energy Technology Data Exchange (ETDEWEB)

Safari, Bonfils [Department of Physics, National University of Rwanda, P.O. Box 117, Huye District, South Province (Rwanda)

2011-02-15

Utilization of wind energy as an alternative energy source may offer many environmental and economical advantages compared to fossil fuels based energy sources polluting the lower layer atmosphere. Wind energy as other forms of alternative energy may offer the promise of meeting energy demand in the direct, grid connected modes as well as stand alone and remote applications. Wind speed is the most significant parameter of the wind energy. Hence, an accurate determination of probability distribution of wind speed values is very important in estimating wind speed energy potential over a region. In the present study, parameters of five probability density distribution functions such as Weibull, Rayleigh, lognormal, normal and gamma were calculated in the light of long term hourly observed data at four meteorological stations in Rwanda for the period of the year with fairly useful wind energy potential (monthly hourly mean wind speed anti v{>=}2 m s{sup -1}). In order to select good fitting probability density distribution functions, graphical comparisons to the empirical distributions were made. In addition, RMSE and MBE have been computed for each distribution and magnitudes of errors were compared. Residuals of theoretical distributions were visually analyzed graphically. Finally, a selection of three good fitting distributions to the empirical distribution of wind speed measured data was performed with the aid of a {chi}{sup 2} goodness-of-fit test for each station. (author)

Wind Energy Forecasting: A Collaboration of the National Center for Atmospheric Research (NCAR) and Xcel Energy

Energy Technology Data Exchange (ETDEWEB)

Parks, K.; Wan, Y. H.; Wiener, G.; Liu, Y.

2011-10-01

. The downside is costs are higher. In organized electricity markets, units that are committed for reliability reasons are paid their offer price even when prevailing market prices are lower. Often, these uplift charges are allocated to market participants that caused the inefficient dispatch in the first place. Thus, wind energy facilities are burdened with their share of costs proportional to their forecast errors. For Xcel Energy, wind energy uncertainty costs manifest depending on specific market structures. In the Public Service of Colorado (PSCo), inefficient commitment and dispatch caused by wind uncertainty increases fuel costs. Wind resources participating in the Midwest Independent System Operator (MISO) footprint make substantial payments in the real-time markets to true-up their day-ahead positions and are additionally burdened with deviation charges called a Revenue Sufficiency Guarantee (RSG) to cover out of market costs associated with operations. Southwest Public Service (SPS) wind plants cause both commitment inefficiencies and are charged Southwest Power Pool (SPP) imbalance payments due to wind uncertainty and variability. Wind energy forecasting helps mitigate these costs. Wind integration studies for the PSCo and Northern States Power (NSP) operating companies have projected increasing costs as more wind is installed on the system due to forecast error. It follows that reducing forecast error would reduce these costs. This is echoed by large scale studies in neighboring regions and states that have recommended adoption of state-of-the-art wind forecasting tools in day-ahead and real-time planning and operations. Further, Xcel Energy concluded reduction of the normalized mean absolute error by one percent would have reduced costs in 2008 by over $1 million annually in PSCo alone. The value of reducing forecast error prompted Xcel Energy to make substantial investments in wind energy forecasting research and development.

Wind power statistics and an evaluation of wind energy density

Energy Technology Data Exchange (ETDEWEB)

Jamil, M.; Parsa, S.; Majidi, M. [Materials and Energy Research Centre, Tehran (Iran, Islamic Republic of)

1995-11-01

In this paper the statistical data of fifty days` wind speed measurements at the MERC- solar site are used to find out the wind energy density and other wind characteristics with the help of the Weibull probability distribution function. It is emphasized that the Weibull and Rayleigh probability functions are useful tools for wind energy density estimation but are not quite appropriate for properly fitting the actual wind data of low mean speed, short-time records. One has to use either the actual wind data (histogram) or look for a better fit by other models of the probability function. (Author)

Response of west Indian coastal regions and Kavaratti lagoon to the November-2009 tropical cyclone Phyan

Digital Repository Service at National Institute of Oceanography (India)

Joseph, A.; Desai, R.G.P.; Mehra, P.; SanilKumar, V.; Radhakrishnan, K.V.; VijayKumar, K.; AshokKumar, K.; Agarwadekar, Y.; Bhat, U.G.; Luis, R.; Rivankar, P.; Viegas, B.

to be ~45 knots (~83 km/h) with gust up to 50 knots (92 km/h) for a temporary period during 11 th morning. The track of Phyan during its onward march from 9 th to 12 th November (Fig. 2) indicates its initial north-westerly motion from the south... in November 2009 illustrates the spatial structure and vortex motion of the wind field (Fig. 13). Because of limited in-situ measurement locations, sea-surface wind (U 10 ), sea-surface waves (significant wave height, wave direction, wave periods), and sea...

Wind Resource Estimation using QuikSCAT Ocean Surface Winds

DEFF Research Database (Denmark)

Xu, Qing; Zhang, Guosheng; Cheng, Yongcun

2011-01-01

In this study, the offshore wind resources in the East China Sea and South China Sea were estimated from over ten years of QuikSCAT scatterometer wind products. Since the errors of these products are larger close to the coast due to the land contamination of radar backscatter signal...... and the complexity of air-sea interaction processes, an empirical relationship that adjusts QuikSCAT winds in coastal waters was first proposed based on vessel measurements. Then the shape and scale parameters of Weibull function are determined for wind resource estimation. The wind roses are also plotted. Results...

Anholt offshore wind farm winds investigated from satellite images

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Badger, Merete; Volker, Patrick

, i.e. before the wind farm was constructed. Based on these data the wind resource is estimated. Concurrent Sentinel-1 SAR data and available SCADA and lidar data, kindly provided by DONG Energy and partners, for the period January 2013 to June 2015 account for ~70 images, while ~300 images...... are available for Sentinel-1 from July 2015 to February 2017. The Sentinel-1 wind maps are investigated for wind farm wake effects. Furthermore the results on wind resources and wakes are compared to the SCADA and model results from WRF, Park, Fuga and RANS models....

Wind Penetration with different wind turbine technologies in a weak grid

International Nuclear Information System (INIS)

Santos Fuentefria, Ariel; Castro Fernandez, Miguel A.; Martínez García, Antonio

2012-01-01

The insertion of wind energy into electric network may provoke stability problems due to stochastic character of wind. The variation in the wind causes voltage variation in the Point of Common Coupling (PCC). In a weakest system that variation is high. Another important factor is wind turbine technology. The use of grid-connected fixed speed wind generator introduces a great consumption of reactive power that can be compensated using different devices as capacitors bank or static var compensator (SVC or STATCOM). In the other hand the variable speed wind turbine have an electronic converter to control the reactive consumption to maintain the PCC voltage more stable. In this paper a comparison between the different types of wind turbines technology is show. It's analyzing the impact in wind power limit for different wind turbine technologies in a weak system. (author)

The winterstorm ``Vivian'' of 27 February 1990: About the meteorological development, wind forces and damage situation in the forests of Switzerland

Science.gov (United States)

Schüepp, M.; Schiesser, H. H.; Huntrieser, H.; Scherrer, H. U.; Schmidtke, H.

1994-09-01

During the months January and February 1990 a series of severe cyclones were responsible for enormous wind-induced damage in Europe. The final of this series, on 27 February 1990, cyclone “Vivian” mainly affected the alpine valleys of Switzerland. 5 Millions m3 of timber were felled by the severe winds, a record number in this century. A complete damage survey of the deforested areas offers in combination with meteorological data an unique data set for a detailed case study of this extreme event. This paper describes the general meteorological development from the synoptic scale down to the mesoscale of Switzerland and presents a general overview of the damage situation. The main results show that a rare situation of a straight frontal zone stretching over the whole Atlantic Ocean and showing a strong gradient in temperature pointed directly toward Central-Europe. Two waves formed along this elongated polar front and deepend rapidly to depressions. The first low travelled on the southernmost trajectory of the whole storm series and affected Switzerland most. North of the Alps the prefrontal warm air was blocked to the east by the arriving coldfront and had to escape into the complex terrain of the alpine valleys. There, the stormy winds were strengthened by channelizing and “Föhn” effects. The large temperature gradient between the prefrontal and the incoming air masses induced thunderstorm activity which vortices and downdrafts might have enhanced locally. As a result most of the damaged forested areas were found between 1200 and 1600 m MSL on slopes, which were mainly exposed toward the prevailing NW-winds. A comparison of extreme wind speeds for the period 1978 1992 revealed that this event's extreme high speed of 74.5 m/s, measured at a high elevated pass station in the mountains, was exceptional. For lower elevated stations the wind speeds were high but in the range of other observed extreme values. In addition to the severe wind forces the duration

A Comparison of Wind Flow Models for Wind Resource Assessment in Wind Energy Applications

Directory of Open Access Journals (Sweden)

Mathieu Landry

2012-10-01

Full Text Available The objective of this work was to assess the accuracy of various coupled mesoscale-microscale wind flow modeling methodologies for wind energy applications. This is achieved by examining and comparing mean wind speeds from several wind flow modeling methodologies with observational measurements from several 50 m met towers distributed across the study area. At the mesoscale level, with a 5 km resolution, two scenarios are examined based on the Mesoscale Compressible Community Model (MC2 model: the Canadian Wind Energy Atlas (CWEA scenario, which is based on standard input data, and the CWEA High Definition (CWEAHD scenario where high resolution land cover input data is used. A downscaling of the obtained mesoscale wind climate to the microscale level is then performed, where two linear microscale models, i.e., MsMicro and the Wind Atlas Analysis and Application Program (WAsP, are evaluated following three downscaling scenarios: CWEA-WAsP, CWEA-MsMicro and CWEAHD-MsMicro. Results show that, for the territory studied, with a modeling approach based on the MC2 and MsMicro models, also known as Wind Energy Simulation Toolkit (WEST, the use of high resolution land cover and topography data at the mesoscale level helps reduce modeling errors for both the mesoscale and microscale models, albeit only marginally. At the microscale level, results show that the MC2-WAsP modeling approach gave substantially better results than both MC2 and MsMicro modeling approaches due to tweaked meso-micro coupling.

CONSTRUCTION TECHNOLOGY DIFFUSION IN DEVELOPING COUNTRIES: LIMITATIONS OF PREVAILING INNOVATION SYSTEMS

Directory of Open Access Journals (Sweden)

Emilia van Egmond-deWilde de Ligny

2008-12-01

Full Text Available The diffusion of innovative technologies in the market is usually a complex and difficult process with a varying degree of success and the effects of the diffused innovative technologies are very un-balanced. The objective of our research is to gain insight into the reasons why the diffusion of innovative technology fails, even though they promise a superior performance compared to incumbent technologies. Drawing on innovation systems theories, we have identified and used the concepts of technological regime, actor network and technology sets to analyze technology diffusion in a case study in the dwelling construction industry in Costa Rica. The results showed bottlenecks in the prevailing innovation system that curtailed the diffusion of an innovative construction technology.

Wind speed dynamical model in a wind farm

DEFF Research Database (Denmark)

Soleimanzadeh, Maryam; Wisniewski, Rafal

2010-01-01

, the dynamic model for wind flow will be established. The state space variables are determined based on a fine mesh defined for the farm. The end goal of this method is to assist the development of a dynamical model of a wind farm that can be engaged for better wind farm control strategies....

On the Response of a Micro Wind Turbine to Wind-Speed Change

OpenAIRE

烏谷, 隆; 渡辺, 公彦; 大屋, 裕二

2004-01-01

To improve the efficiency of a wind turbine, it is more effective to use high-speed wind. A method collecting wind to get high-speed wind was experimentally studied. It was found that the brimmed diffuser was a good device to get high-speed wind. The brimmed diffuser accelerated approaching wind, and wind speed near its inlet became about 1.7 times. Using this brimmed diffuser, we have made a new micro wind turbine and been carrying out field experiment. In order realize the properties of the...

Wind-driven snow conditions control the occurrence of contemporary marginal mountain permafrost in the Chic-Choc Mountains, south-eastern Canada: a case study from Mont Jacques-Cartier

Directory of Open Access Journals (Sweden)

G. Davesne

2017-06-01

Full Text Available We present data on the distribution and thermophysical properties of snow collected sporadically over 4 decades along with recent data of ground surface temperature from Mont Jacques-Cartier (1268 m a.s.l., the highest summit in the Appalachians of south-eastern Canada. We demonstrate that the occurrence of contemporary permafrost is necessarily associated with a very thin and wind-packed winter snow cover which brings local azonal topo-climatic conditions on the dome-shaped summit. The aims of this study were (i to understand the snow distribution pattern and snow thermophysical properties on the Mont Jacques-Cartier summit and (ii to investigate the impact of snow on the spatial distribution of the ground surface temperature (GST using temperature sensors deployed over the summit. Results showed that above the local treeline, the summit is characterized by a snow cover typically less than 30 cm thick which is explained by the strong westerly winds interacting with the local surface roughness created by the physiography and surficial geomorphology of the site. The snowpack structure is fairly similar to that observed on windy Arctic tundra with a top dense wind slab (300 to 450 kg m−3 of high thermal conductivity, which facilitates heat transfer between the ground surface and the atmosphere. The mean annual ground surface temperature (MAGST below this thin and wind-packed snow cover was about −1 °C in 2013 and 2014, for the higher, exposed, blockfield-covered sector of the summit characterized by a sporadic herbaceous cover. In contrast, for the gentle slopes covered with stunted spruce (krummholz, and for the steep leeward slope to the south-east of the summit, the MAGST was around 3 °C in 2013 and 2014. The study concludes that the permafrost on Mont Jacques-Cartier, most widely in the Chic-Choc Mountains and by extension in the southern highest summits of the Appalachians, is therefore likely limited to the barren wind

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.

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…

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.

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...

Design optimization of offshore wind farms with multiple types of wind turbines

DEFF Research Database (Denmark)

Feng, Ju; Shen, Wen Zhong

2017-01-01

Most studies on offshore wind farm design assume a uniform wind farm, which consists of an identical type of wind turbines. In order to further reduce the cost of energy, we investigate the design of non-uniform offshore wind farms, i.e., wind farms with multiple types of wind turbines and hub-he...

Evolution of wind towards wind turbine

NARCIS (Netherlands)

Giyanani, A.H.; Bierbooms, W.A.A.M.; Van Bussel, G.J.W.

2015-01-01

Remote sensing of the atmospheric variables with the use of LiDAR is a relatively new technology field for wind resource assessment in wind energy. The validation of LiDAR measurements and comparisons is of high importance for further applications of the data.

WindNet: Improving the impact assessment of wind power projects

Directory of Open Access Journals (Sweden)

Christopher R. Jones

2014-12-01

Full Text Available Growing international demand for renewable energy has led to rapid growth in the wind power sector and wind farms are becoming an increasingly common feature of landscapes and seascapes in many countries. However, as the most appropriate locations within established markets are taken up, and as wind power penetrates new markets, there is an increasing likelihood that proposed projects will encroach on sensitive landscapes and residential areas. This will present challenges for the industry, particularly due to the impact that public opinion can have upon the outcomes of planning decisions about specific projects. This article introduces the four key dimensions of the WindNet programme, which are helping to elucidate some of the socio-technical debates that will likely shape the future of the wind power sector. The article outlines studies investigating (1 public responses to cumulative landscape and visual impacts, (2 the auditory impact of wind power projects on human health, (3 the science of wind farm design and its implications for planning, and (4 the relevance of the democratic deficit explanation of the so-called "social gap" in wind farm siting. The outcomes of the research being conducted by WindNet stand to help reduce uncertainty within the planning process and assist in providing a more comprehensive and fairer assessment of the possible impacts associated with wind power project development.

Canadian Wind Energy Association small wind conference proceedings : small wind policy developments (turbines of 300 kW or less)

International Nuclear Information System (INIS)

2005-01-01

The small wind session at the Canadian Wind Energy Association's (CanWEA) annual conference addressed policies affecting small wind, such as net metering, advanced renewable tariffs and interconnections. It also addressed CanWEA's efforts in promoting small wind turbines, particularly in remote northern communities, small businesses and within the residential sector. Small wind systems are typically installed in remote communities to offset utility supplied electricity at the retail price level. In certain circumstances, small wind and hybrid systems can produce electricity at less than half the cost of traditional electricity sources, which in remote communities is typically diesel generators. Small wind turbines require different materials and technologies than large wind turbines. They also involve different local installation requirements, different by-laws, tax treatment and environmental assessments. Small wind turbines are typically installed for a range of factors, including energy independence, energy price stability and to lower environmental impacts of traditional power generation. The small wind session at the conference featured 14 presentations, of which 4 have been catalogued separately for inclusion in this database. tabs., figs

Wind: French revolutions

International Nuclear Information System (INIS)

Jones, C.

2006-01-01

Despite having the second best wind resources in Europe after the UK, the wind industry in France lags behind its European counterparts with just 6 W of installed wind capacity per person. The electricity market in France is dominated by the state-owned Electricite de France (EdF) and its nuclear power stations. However, smaller renewable generators are now in theory allowed access to the market and France has transposed the EU renewables directive into national law. The French governement has set a target of generating 10,000 MW of renewable capacity by 2010. The announcement of an increased feed-in tariff and the introduction of 'development zones' (ZDEs) which could allow fast-tracking of planning for wind projects are also expected to boost wind projects. But grid access and adminstrative burdens remain major barriers. In addition, French politicians and local authorities remain committed to nuclear, though encouraged by the European Commission, wind is beginning to gain acceptance; some 325 wind farms (representing 1557 MW of capacity) were approved between February 2004 and January 2005. France is now regarded by the international wind energy sector as a target market. One of France's leading independent wind developers and its only listed wind company, Theolia, is expected to be one of the major beneficiaries of the acceleration of activity in France, though other companies are keen to maximise the opportunities for wind. France currently has only one indigenous manufacturer of wind turbines, but foreign suppliers are winning orders

Wind energy systems

Science.gov (United States)

Stewart, H. J.

1978-01-01

A discussion on wind energy systems involved with the DOE wind energy program is presented. Some of the problems associated with wind energy systems are discussed. The cost, efficiency, and structural design of wind energy systems are analyzed.

An extended structure-function model and its application to the analysis of solar wind intermittency properties

Directory of Open Access Journals (Sweden)

C.-Y. Tu

Full Text Available An extended structure-function model is developed by including the new effect in the p-model of Meneveau and Sreenivasan which shows that the averaged energy cascade rate changes with scale, a situation which has been found to prevail in non-fully-developed turbulence in the inner solar wind. This model is useful for the small-scale fluctuations in the inner heliosphere, where the turbulence is not fully developed and cannot be explained quantitatively by any of the previous intermittency turbulence models. With two model parameters, the intrinsic index of the energy spectrum α, and the fragmentation fraction P₁, the model can fit, for the first time, all the observed scaling exponents of the structure functions, which are calculated for time lags ranging from 81 s to 0.7 h from the Helios solar wind data. From the cases we studied we cannot establish for P₁ either a clear radial evolution trend, or a solar-wind-speed or stream-structure dependence or a systematic anisotropy for both the flow velocity and magnetic field component fluctuations. Generally, P₁ has values between 0.7 and 0.8. However, in some cases in low-speed wind P₁ has somewhat higher values for the magnetic components, especially for the radial component. In high-speed wind, the inferred intrinsic spectral indices α of the velocity and magnetic field components are about equal, while the experimental spectral indices derived from the observed power spectra differ. The magnetic index is somewhat larger than the index of the velocity spectrum. For magnetic fluctuations in both high- and low-speed winds, the intrinsic exponent α has values which are near 1.5, while the observed spectral exponent has much higher values. In the solar wind with considerable density fluctuations near the interplanetary current sheet near 1 AU, it is found that P₁ has a comparatively high value of 0

Analysis of the prevailing standard and technical documents for their applicability under conditions of the 'Ukrytie' operation and technical proposals relating to the elaboration of new ones concerning fire safety

International Nuclear Information System (INIS)

Nazarenko, B.S.; Emets, V.G.

1998-01-01

An analysis of the prevailing laws and standards and technical documents (STD) to ensure safe operation of nuclear power installations, with requirements of nuclear, radiation and fire safety taken into account, has been performed. Proposals on application of some items of prevailing STD under conditions of the 'Ukrytie' operation are presented. Also given are technical proposals on correction of the prevailing operational standard documents and elaboration of special STD

Wind Predictions Upstream Wind Turbines from a LiDAR Database

Directory of Open Access Journals (Sweden)

Soledad Le Clainche

2018-03-01

Full Text Available This article presents a new method to predict the wind velocity upstream a horizontal axis wind turbine from a set of light detection and ranging (LiDAR measurements. The method uses higher order dynamic mode decomposition (HODMD to construct a reduced order model (ROM that can be extrapolated in space. LiDAR measurements have been carried out upstream a wind turbine at six different planes perpendicular to the wind turbine axis. This new HODMD-based ROM predicts with high accuracy the wind velocity during a timespan of 24 h in a plane of measurements that is more than 225 m far away from the wind turbine. Moreover, the technique introduced is general and obtained with an almost negligible computational cost. This fact makes it possible to extend its application to both vertical axis wind turbines and real-time operation.

Wind power today

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-04-01

This publication highlights initiatives of the US DOE`s Wind Energy Program. 1997 yearly activities are also very briefly summarized. The first article describes a 6-megawatt wind power plant installed in Vermont. Another article summarizes technical advances in wind turbine technology, and describes next-generation utility and small wind turbines in the planning stages. A village power project in Alaska using three 50-kilowatt turbines is described. Very brief summaries of the Federal Wind Energy Program and the National Wind Technology Center are also included in the publication.

Financing wind projects

International Nuclear Information System (INIS)

Manson, J.

2006-01-01

This presentation reviewed some of the partnership opportunities available from GE Energy. GE Energy's ecomagination commitment has promised to double research investment, make customers true partners and reduce greenhouse gases (GHGs). GE Energy's renewable energy team provides a broad range of financial products, and has recently funded 30 wind farms and 2 large solar projects. The company has a diverse portfolio of technology providers and wind regimes, and is increasing their investment in technology. GE Energy recognizes that the wind industry is growing rapidly and has received increased regulatory support that is backed by strong policy and public support. It is expected that Canada will have 3006 wind projects either planned or under construction by 2007. According to GE Energy, successful wind financing is dependent on the location of the site and its wind resources, as well as on the wind developer's power sales agreement. The success of a wind project is also determined by clear financing goals. Site-specific data is needed to determine the quality of wind resource, and off-site data can also be used to provide validation. Proximity to load centres will help to minimize capital costs. Power sales agreements should be based on the project's realistic net capacity factor as well as on the cost of the turbines. The economics of many wind farms is driven by the size of the turbines used. Public consultations are also needed to ensure the success of wind power projects. It was concluded that a good partner will have staying power in the wind power industry, and will understand the time-lines and needs that are peculiar to wind energy developers. refs., tabs., figs

Wind energy

International Nuclear Information System (INIS)

Kotevski, Darko

2003-01-01

Wind is not only free, it is inexhaustible. Wind energy has come a very long way since the prototypes of just 20 years ago. today's wind turbines are state-of-the-art technology - modular and quick to install anywhere where there is sufficient wind potential to provide secure, centralised or distributed generation. It is a global phenomenon, the world's fastest growing energy sector, a clean and effective modern technology that completely avoids pollution and thus reducing the 'green house' effect. (Original)

Benchmarking U.S. Small Wind Costs with the Distributed Wind Taxonomy

Energy Technology Data Exchange (ETDEWEB)

Orrell, Alice C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poehlman, Eric A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-10-04

The objective of this report is to benchmark costs for small wind projects installed in the United States using a distributed wind taxonomy. Consequently, this report is a starting point to help expand the U.S. distributed wind market by informing potential areas for small wind cost-reduction opportunities and providing a benchmark to track future small wind cost-reduction progress.

Wind energy statistics

International Nuclear Information System (INIS)

Holttinen, H.; Tammelin, B.; Hyvoenen, R.

1997-01-01

The recording, analyzing and publishing of statistics of wind energy production has been reorganized in cooperation of VTT Energy, Finnish Meteorological (FMI Energy) and Finnish Wind Energy Association (STY) and supported by the Ministry of Trade and Industry (KTM). VTT Energy has developed a database that contains both monthly data and information on the wind turbines, sites and operators involved. The monthly production figures together with component failure statistics are collected from the operators by VTT Energy, who produces the final wind energy statistics to be published in Tuulensilmae and reported to energy statistics in Finland and abroad (Statistics Finland, Eurostat, IEA). To be able to verify the annual and monthly wind energy potential with average wind energy climate a production index in adopted. The index gives the expected wind energy production at various areas in Finland calculated using real wind speed observations, air density and a power curve for a typical 500 kW-wind turbine. FMI Energy has produced the average figures for four weather stations using the data from 1985-1996, and produces the monthly figures. (orig.)

Wind energy power plants (wind farms) review and analysis

Energy Technology Data Exchange (ETDEWEB)

Newbold, K B; McKeary, M [McMaster Univ., Hamilton, ON (Canada). McMaster Inst. of Environment and Health

2010-07-01

Global wind power capacity has increased by an average cumulative rate of over 30 percent over the past 10 years. Although wind energy emits no air pollutants and facilities can often share spaces with other activities, public opposition to wind power development is an ongoing cause of concern. Development at the local level in Ontario has been met with fierce opposition on the basis of health concerns, aesthetic values, potential environmental impacts, and economic risks. This report was prepared for the Town of Wasaga Beach, and examined some of the controversy surrounding wind power developments through a review of evidence found in the scientific literature. The impacts of wind power developments related to noise, shadow flicker, avian mortality, bats, and real estate values were evaluated. The study included details of interviews conducted with individuals from Ontario localities where wind farms were located. 77 refs., 1 tab., 1 fig., 2 appendices.

Wind Resource Assessment – Østerild National Test Centre for Large Wind Turbines

OpenAIRE

Hansen, Brian Ohrbeck; Courtney, Michael; Mortensen, Niels Gylling

2014-01-01

This report presents a wind resource assessment for the seven test stands at the Østerild National Test Centre for Large Wind Turbines in Denmark. Calculations have been carried out mainly using wind data from three on-site wind lidars. The generalized wind climates applied in the wind resource calculations for the seven test stands are based on correlations between a short period of on-site wind data from the wind lidars with a long-term reference. The wind resource assessment for the seven ...

75 FR 47301 - Cedro Hill Wind LLC; Butler Ridge Wind Energy Center, LLC; High Majestic Wind Energy Center, LLC...

Science.gov (United States)

2010-08-05

...- 000; EG10-34-000; EG10-34-000; EG10-35-000; EG10-36-000; EG10-37-000; EG10-38-000] Cedro Hill Wind LLC; Butler Ridge Wind Energy Center, LLC; High Majestic Wind Energy Center, LLC; Wessington Wind Energy Center, LLC; Juniper Canyon Wind Power LLC; Loraine Windpark Project, LLC; White Oak Energy LLC; Meadow...

Urban Wind Energy

DEFF Research Database (Denmark)

Beller, Christina

important for the implementation of wind energy conversion systems are the macro and micro wind climate, the siting within a micro wind climate and the choice of a wind turbine model most appropriate for the selected site. In the frame of this work, all these important elements are analyzed and a row......New trends e.g. in architecture and urban planning are to reduce energy needs. Several technologies are employed to achieve this, and one of the technologies, not new as such, is wind energy. Wind turbines are installed in cities, both by companies and private persons on both old and new buildings....... However, an overview of the energy content of the wind in cities and how consequently turbines shall be designed for such wind climates is lacking. The objective of the present work is to deliver an objective and fundamental overview of the social, practical and physical conditions relevant...

Does undernutrition still prevail among nursing home residents?

Science.gov (United States)

Törmä, Johanna; Winblad, Ulrika; Cederholm, Tommy; Saletti, Anja

2013-08-01

During recent years public awareness about malnutrition has increased and collective initiatives have been undertaken. Simultaneously, the number of older adults is increasing, and the elderly care has been placed under pressure. The aim was to assess the nutritional situation and one-year mortality among nursing home (NH) residents, and compare with historical data. Mini Nutritional Assessment-Short Form (MNA-SF), ADL Barthel Index (BI), Short Portable Mental Status Questionnaire (SPMSQ), EQ-5D, Charlson Comorbidity Index (CCI), and blood samples were collected from 172 NH residents (86.3 ± 8 years, 70% women). Mortality data was taken from NH records. Nutritional data from 166 NH residents (83.8 ± 8 years, 61% women) examined in 1996 was retrieved for historical comparison. The prevalence of malnutrition was 30%, as compared to 71% in the historical data set, corresponding to a present average body mass index of 23.7 ± 5.1 compared with 22.3 ± 4.2 kg/m(2) (p prevails and is associated with deteriorated cognition, function and increased mortality. A possible improvement in nutritional status in NH residents over time was observed. Copyright © 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Post hoc analysis of Japanese patients from the placebo-controlled PREVAIL trial of enzalutamide in patients with chemotherapy-naive, metastatic castration-resistant prostate cancer-updated results.

Science.gov (United States)

Kimura, Go; Ueda, Takeshi

2017-03-01

A post hoc analysis of interim results from PREVAIL, a Phase III, double-blind, placebo-controlled trial of men with metastatic castration-resistant prostate cancer, demonstrated that the treatment effects, safety and pharmacokinetics of enzalutamide in Japanese patients were generally consistent with those of the overall population. A recent longer term analysis of PREVAIL demonstrated continued benefit of enzalutamide treatment over placebo. Here, we report results from a post hoc analysis of Japanese patients enrolled in PREVAIL at the prespecified number of deaths for the final analysis. In Japanese patients, enzalutamide reduced the risk of death by 35% (hazard ratio, 0.65; 95% confidence interval, 0.28-1.51) and the risk of investigator-assessed radiographic progression or death by 60% (hazard ratio, 0.40; 95% confidence interval, 0.18-0.90). These results show that treatment effects and safety in Japanese patients in the final analysis of PREVAIL continued to be generally consistent with those of the overall population. © The Author 2016. Published by Oxford University Press.

Wind power barometer

International Nuclear Information System (INIS)

2014-01-01

The worldwide wind power increased by 12.4% in 2013 to reach 318.6 GW but the world market globally decreased by losing 10 GW: only 35.6 GW have been installed in 2013 which is even less than was installed in 2009. This activity contraction is mainly due to the collapse of the American market, American authorities having been late to decide to maintain federal incentives. The European wind power market also contracted in 2013 because of the lack of trust of the investors in the new energy policies of the European governments. In the rest of the world wind energy has kept on growing particularly in China and Canada. At the end of 2013 the cumulated wind power reached 117,73 GW in Europe. About 1.5 MW out of 10 MW of wind power installed in Europe in 2013 come from off-shore wind farms, United-Kingdom and Denmark being the most important players by totalling more than 70% of the off-shore wind power installed at the end of 2013. Various charts and tables give the figures of the wind power cumulated and installed in 2013 in different parts of the world: Europe, North America and Asia, the time evolution of the worldwide wind power since 1995, the wind power cumulated and installed in 2013 for the different countries of Europe and the ratio between the cumulated wind power and the country population. A table lists the main manufacturers of wind turbines and gives their turnover and number of employees at the end of 2013

Wind Data Analysis and Wind Flow Simulation Over Large Areas

Directory of Open Access Journals (Sweden)

Terziev Angel

2014-03-01

Full Text Available Increasing the share of renewable energy sources is one of the core policies of the European Union. This is because of the fact that this energy is essential in reducing the greenhouse gas emissions and securing energy supplies. Currently, the share of wind energy from all renewable energy sources is relatively low. The choice of location for a certain wind farm installation strongly depends on the wind potential. Therefore the accurate assessment of wind potential is extremely important. In the present paper an analysis is made on the impact of significant possible parameters on the determination of wind energy potential for relatively large areas. In the analysis the type of measurements (short- and long-term on-site measurements, the type of instrumentation and the terrain roughness factor are considered. The study on the impact of turbulence on the wind flow distribution over complex terrain is presented, and it is based on the real on-site data collected by the meteorological tall towers installed in the northern part of Bulgaria. By means of CFD based software a wind map is developed for relatively large areas. Different turbulent models in numerical calculations were tested and recommendations for the usage of the specific models in flows modeling over complex terrains are presented. The role of each parameter in wind map development is made. Different approaches for determination of wind energy potential based on the preliminary developed wind map are presented.

PV–wind hybrid power option for a low wind topography

International Nuclear Information System (INIS)

Bhattacharjee, Subhadeep; Acharya, Shantanu

2015-01-01

Highlights: • Optimally harness the wind energy by unification of solar resource. • Analysis of PV–wind hybrid system with tangible experience. • Cost of generation and renewable fraction are $0.488/kWh and 0.90 respectively. • Maximum wind penetration is observed to be 32.75% with installed PV–wind system. • Indicative annual grid electricity conservation is 90%. - Abstract: Solar and wind are clean energy sources with enormous potential to alleviate grid dependence. The paper aims to optimally harness the wind resource with the support of solar energy through hybrid technology for a north-east Indian state Tripura (low wind topography). Techno-economic analysis of a photovoltaic (PV)-wind hybrid simulation model has been performed for small scale application in an educational building. The study also evaluates the tangible performance of a similar plant in practical condition of the site. It has emerged from the study that major energy generation is turning out from PV segment which is promising almost all round the year. Nonetheless, a considerable amount of wind power is found to be generated during half of the year when average PV power production is comparatively less. The cost of electricity from the simulation model is found to be $0.488/kWh while renewable fraction in the total electricity share is obtained to be 0.90. From the actual performance of the plant, maximum wind penetration is observed to be 32.75%

Wind energy assessment and wind farm simulation in Triunfo - Pernambuco, Brazil

Energy Technology Data Exchange (ETDEWEB)

Lima, Laerte; Filho, Celso

2010-09-15

The Triunfo wind's characterization, in Pernambuco state, situated in Brazilian northeast, and wind power potential assessment study shows a average wind speed of 11.27 m / s, predominant Southeast wind direction, average wind power density of 1672 W/m2 and Weibull parameters shape and scale equal to 2,0 and 12,7 m/s. The wind farm was simulated by using 850kW wind turbines (total of 20MW). The simulated shows AEP of 111,4 GWh, Cf of 62% and 5462 hours of operation by year. The economical simulated results, shows Pay-back of 3 years, TIR = 47% and VAN = 85.506kEuro booths @ 20 years time period.

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

Far offshore wind conditions in scope of wind energy

NARCIS (Netherlands)

Holtslag, M.C.

2016-01-01

Far offshore atmospheric conditions are favourable for wind energy purposes since mean wind speeds are relatively high (i.e., high power production) while turbulence levels are relatively low (i.e., less fatigue loads) compared to onshore conditions. Offshore wind energy, however, is still expensive

Operating wind turbines in strong wind conditions by using feedforward-feedback control

International Nuclear Information System (INIS)

Feng, Ju; Sheng, Wen Zhong

2014-01-01

Due to the increasing penetration of wind energy into power systems, it becomes critical to reduce the impact of wind energy on the stability and reliability of the overall power system. In precedent works, Shen and his co-workers developed a re-designed operation schema to run wind turbines in strong wind conditions based on optimization method and standard PI feedback control, which can prevent the typical shutdowns of wind turbines when reaching the cut-out wind speed. In this paper, a new control strategy combing the standard PI feedback control with feedforward controls using the optimization results is investigated for the operation of variable-speed pitch-regulated wind turbines in strong wind conditions. It is shown that the developed control strategy is capable of smoothening the power output of wind turbine and avoiding its sudden showdown at high wind speeds without worsening the loads on rotor and blades

Wind Vision: A New Era for Wind Power in the United States

Energy Technology Data Exchange (ETDEWEB)

U.S. Department of Energy

2015-03-12

With more than 4.5% of the nation's electricity supplied by wind energy today, the Department of Energy has collaborated with industry, environmental organizations, academic institutions, and national laboratories to develop a renewed Wind Vision, documenting the contributions of wind to date and envisioning a future where wind continues to provide key contributions to the nation’s energy portfolio. Building on and updating the 2008 20% Wind Energy by 2030 report, the new Wind Vision Report quantifies the economic, environmental, and social benefits of a robust wind energy future and the actions that wind stakeholders can take to make it a reality.