Science.gov

Sample records for vector wind change

  1. Analysis of vector wind change with respect to time for Cape Kennedy, Florida

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1978-01-01

    Multivariate analysis was used to determine the joint distribution of the four variables represented by the components of the wind vector at an initial time and after a specified elapsed time is hypothesized to be quadravariate normal; the fourteen statistics of this distribution, calculated from 15 years of twice-daily rawinsonde data are presented by monthly reference periods for each month from 0 to 27 km. The hypotheses that the wind component changes with respect to time is univariate normal, that the joint distribution of wind component change with respect to time is univariate normal, that the joint distribution of wind component changes is bivariate normal, and that the modulus of vector wind change is Rayleigh are tested by comparison with observed distributions. Statistics of the conditional bivariate normal distributions of vector wind at a future time given the vector wind at an initial time are derived. Wind changes over time periods from 1 to 5 hours, calculated from Jimsphere data, are presented. Extension of the theoretical prediction (based on rawinsonde data) of wind component change standard deviation to time periods of 1 to 5 hours falls (with a few exceptions) within the 95 percentile confidence band of the population estimate obtained from the Jimsphere sample data. The joint distributions of wind change components, conditional wind components, and 1 km vector wind shear change components are illustrated by probability ellipses at the 95 percentile level.

  2. Analysis of vector wind change with respect to time for Cape Kennedy, Florida: Wind aloft profile change vs. time, phase 1

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1977-01-01

    Wind vector change with respect to time at Cape Kennedy, Florida, is examined according to the theory of multivariate normality. The joint distribution of the four variables represented by the components of the wind vector at an initial time and after a specified elapsed time is hypothesized to be quadravariate normal; the fourteen statistics of this distribution, calculated from fifteen years of twice daily Rawinsonde data are presented by monthly reference periods for each month from 0 to 27 km. The hypotheses that the wind component changes with respect to time is univariate normal, the joint distribution of wind component changes is bivariate normal, and the modulus of vector wind change is Rayleigh, has been tested by comparison with observed distributions. Statistics of the conditional bivariate normal distributions of vector wind at a future time given the vector wind at an initial time are derived. Wind changes over time periods from one to five hours, calculated from Jimsphere data, are presented.

  3. Vector wind profile gust model

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1979-01-01

    Work towards establishing a vector wind profile gust model for the Space Transportation System flight operations and trade studies is reported. To date, all the statistical and computational techniques required were established and partially implemented. An analysis of wind profile gust at Cape Kennedy within the theoretical framework is presented. The variability of theoretical and observed gust magnitude with filter type, altitude, and season is described. Various examples are presented which illustrate agreement between theoretical and observed gust percentiles. The preliminary analysis of the gust data indicates a strong variability with altitude, season, and wavelength regime. An extension of the analyses to include conditional distributions of gust magnitude given gust length, distributions of gust modulus, and phase differences between gust components has begun.

  4. Vector wind profile gust model

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1981-01-01

    To enable development of a vector wind gust model suitable for orbital flight test operations and trade studies, hypotheses concerning the distributions of gust component variables were verified. Methods for verification of hypotheses that observed gust variables, including gust component magnitude, gust length, u range, and L range, are gamma distributed and presented. Observed gust modulus has been drawn from a bivariate gamma distribution that can be approximated with a Weibull distribution. Zonal and meridional gust components are bivariate gamma distributed. An analytical method for testing for bivariate gamma distributed variables is presented. Two distributions for gust modulus are described and the results of extensive hypothesis testing of one of the distributions are presented. The validity of the gamma distribution for representation of gust component variables is established.

  5. The change in wind vector and dust storm in the Middle East in last 32 years and their correlations

    NASA Astrophysics Data System (ADS)

    Jin, Q.; Yang, Z.

    2011-12-01

    [1] Winds play an important role in dust aerosols emission, transport, and deposition. Using NCEP reanalysis2 data, the changes in wind direction and speed during 1948 and 2010 were analyzed over the Middle East (the Gulf of Omen and Eastern Saudi Arabia abbreviated as R1). Wind patterns from R1 were compared with those in South Asia Monsoon Area (R2), East China (R3), and East China Sea (R4). The Weather Research and Forecasting model with online chemistry (WRF-Chem) was used to study the effects of winds change on dust emissions over the period from 1979 to 2010. Modifications to soil types and land cover types were implemented to the default WRF-Chem MOSAIC dust scheme to ensure realistic simulations of dust emissions. In all the four regions, the yearly average wind speed decreased. In R1 and R3, winds greater than 2.5 m/s exhibited a decreasing trend throughout the year; while in R2 and R4, the decreasing trend was found only in spring and summer. The model simulations were compared with available observations including satellite data (e.g. AERONET and Calipso) and continual improvements are being made to revise the dust emission scheme within WRF-Chem.

  6. SSM/I and ECMWF Wind Vector Comparison

    NASA Technical Reports Server (NTRS)

    Wentz, Frank J.; Ashcroft, Peter D.

    1996-01-01

    Wentz was the first to convincingly show that satellite microwave radiometers have the potential to measure the oceanic wind vector. The most compelling evidence for this conclusion was the monthly wind vector maps derived solely from a statistical analysis of Special Sensor Microwave Imager (SSM/I) observations. In a qualitative sense, these maps clearly showed the general circulation over the world's oceans. In this report we take a closer look at the SSM/I monthly wind vector maps and compare them to European Center for Medium-Range Weather Forecasts (ECMWF) wind fields. This investigation leads both to an empirical comparison of SSM/I calculated wind vectors with ECMWF wind vectors, and to an examination of possible reasons that the SSM/I calculated wind vector direction would be inherently more reliable at some locations than others.

  7. User's Guide for Monthly Vector Wind Profile Model

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1999-01-01

    The background, theoretical concepts, and methodology for construction of vector wind profiles based on a statistical model are presented. The derived monthly vector wind profiles are to be applied by the launch vehicle design community for establishing realistic estimates of critical vehicle design parameter dispersions related to wind profile dispersions. During initial studies a number of months are used to establish the model profiles that produce the largest monthly dispersions of ascent vehicle aerodynamic load indicators. The largest monthly dispersions for wind, which occur during the winter high-wind months, are used for establishing the design reference dispersions for the aerodynamic load indicators. This document includes a description of the computational process for the vector wind model including specification of input data, parameter settings, and output data formats. Sample output data listings are provided to aid the user in the verification of test output.

  8. Measurement of oceanic wind vector using satellite microwave radiometers

    NASA Technical Reports Server (NTRS)

    Wentz, Frank J.

    1992-01-01

    A feasibility study of deriving both a wind speed and direction from microwave radiometer measurements of the ocean is presented. The study was based on the Special Sensor Microwave/Imager (SSM/I) measurements in conjunction with buoy reports from the National Data Buoy Center. It was found that the SSM/I minus the buoy wind speed difference is correlated with wind direction due to a wind direction signal in the brightness temperatures. When this wind direction signal is removed the rms difference between the SSM/I and buoy winds reduces to 1.3 m/s. The wind direction signal was used to make global, low-resolution maps of the monthly mean oceanic wind vector.

  9. The winds of change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind-based power generation has been growing steadily in the United States and around the world, and this growth will continue—and accelerate—in the future, as the following background statistics demonstrate. The U.S. wind industry installed 8,358 megawatts (MW) of new wind generating capacity in 20...

  10. Rapid Temporal Changes of Midtropospheric Winds

    NASA Technical Reports Server (NTRS)

    Merceret, Francis J.

    1997-01-01

    The statistical distribution of the magnitude of the vector wind change over 0.25-, 1-, 2-. and 4-h periods based on data from October 1995 through March 1996 over central Florida is presented. The wind changes at altitudes from 6 to 17 km were measured using the Kennedy Space Center 50-MHz Doppler radar wind profiler. Quality controlled profiles were produced every 5 min for 112 gates, each representing 150 m in altitude. Gates 28 through 100 were selected for analysis because of their significance to ascending space launch vehicles. The distribution was found to be lognormal. The parameters of the lognormal distribution depend systematically on the time interval. This dependence is consistent with the behavior of structure functions in the f(exp 5/3) spectral regime. There is a small difference between the 1995 data and the 1996 data, which may represent a weak seasonal effect.

  11. Vector wind, horizontal divergence, wind stress and wind stress curl from SEASAT-SASS at one degree resolution

    NASA Technical Reports Server (NTRS)

    Pierson, W. J., Jr.; Sylvester, W. B.; Salfi, R. E.

    1984-01-01

    Conventional data obtained in 1983 are contrasted with SEASAT-A scatterometer and scanning multichannel microwave radiometer (SMMR) data to show how observations at a single station can be extended to an area of about 150,000 square km by means of remotely sensed data obtained in nine minutes. Superobservations at a one degree resolution for the vector winds were estimated along with their standard deviations. From these superobservations, the horizontal divergence, vector wind stress, and the curl of the wind stress can be found. Weather forecasting theory is discussed and meteorological charts of the North Pacific Ocean are presented. Synoptic meteorology as a technique is examined.

  12. Designing Scatterometer Constellations for Sampling Global Ocean Vector Winds

    NASA Astrophysics Data System (ADS)

    Rodriguez, E.; Chelton, D. B.; Stoffelen, A.; Schlax, M.

    2012-12-01

    The rapid temporal variations in ocean vector winds make it impossible to obtain synoptic global snapshots of winds and wind stress from a single spaceborne sensor. Even when multiple sensors are present, the peculiarities of the resulting space-time sampling pattern require that significant smoothing in space and time be performed to limit spatially and temporally inhomogeneous error characteristics in the merged data. Based on the collected common experience in its member states, the World Meteorological Organization collects requirements for spatio-temporal sampling in meteorological applications such as global and regional Numerical Weather Prediction, nowcasting, and climate. An additional concern, when constructing data sets from sun-synchronous missions, is that undersampling of diurnal and sub-diurnal variability may result in aliasing of the climate data record. Indeed, examination of climatologies constructed from different satellite missions, such as NASA's QuikSCAT and EUMETSAT's ASCAT scatterometers, show systematic differences that cannot be explained as being due solely to unresolved incoherent diurnal and sub-diurnal variability. Some of these differences, especially in the tropics, are probably explained by systematic diurnal and sub-diurnal variations. Other differences may be due to the difficulty of cross-calibrating sun-synchronous satellites with different local times. Forthcoming satellite missions may offer the possibility of overcoming or mitigating the space-time sampling and calibration challenges using multiple coordinated platforms. In the next decade, there is an expectation that ocean vector winds will be measured simultaneously by multiple satellites from the European community, India, China, and the United States. The coordination and suitable merging of the data from these satellites to produce a climate data record will be a challenge to the ocean vector winds community. In this presentation, we use climatologies constructed from

  13. A Statistical Approach to WindSat Ocean Surface Wind Vector Retrieval

    DTIC Science & Technology

    2006-01-01

    control number. 1. REPORT DATE JAN 2006 2. REPORT TYPE 3. DATES COVERED 00-00-2006 to 00-00-2006 4. TITLE AND SUBTITLE A Statistical Approach...the second technique to retrieve wind direction, for which the signal in all the is severely nonlinear (in fact nonunique ) and depends on wind speed...vectors [11]. The regression training dataset is quality controlled through exclusion of every condition listed in the next paragraph and SDRs that are

  14. Triboelectric nanogenerator for harvesting wind energy and as self-powered wind vector sensor system.

    PubMed

    Yang, Ya; Zhu, Guang; Zhang, Hulin; Chen, Jun; Zhong, Xiandai; Lin, Zong-Hong; Su, Yuanjie; Bai, Peng; Wen, Xiaonan; Wang, Zhong Lin

    2013-10-22

    We report a triboelectric nanogenerator (TENG) that plays dual roles as a sustainable power source by harvesting wind energy and as a self-powered wind vector sensor system for wind speed and direction detection. By utilizing the wind-induced resonance vibration of a fluorinated ethylene-propylene film between two aluminum foils, the integrated TENGs with dimensions of 2.5 cm × 2.5 cm × 22 cm deliver an output voltage up to 100 V, an output current of 1.6 μA, and a corresponding output power of 0.16 mW under an external load of 100 MΩ, which can be used to directly light up tens of commercial light-emitting diodes. Furthermore, a self-powered wind vector sensor system has been developed based on the rationally designed TENGs, which is capable of detecting the wind direction and speed with a sensitivity of 0.09 μA/(m/s). This work greatly expands the applicability of TENGs as power sources for self-sustained electronics and also self-powered sensor systems for ambient wind detection.

  15. Impact of Scatterometer Ocean Wind Vector Data on NOAA Operations

    NASA Astrophysics Data System (ADS)

    Jelenak, Z.; Chang, P.; Brennan, M. J.; Sienkiewicz, J. M.

    2015-12-01

    Near real-time measurements of ocean surface vector winds (OSVW), including both wind speed and direction from non-NOAA satellites, are being widely used in critical operational NOAA forecasting and warning activities. The scatterometer wind data data have had major operational impact in: a) determining wind warning areas for mid-latitude systems (gale, storm,hurricane force); b) determining tropical cyclone 34-knot and 50-knot wind radii. c) tracking the center location of tropical cyclones, including the initial identification of their formation. d) identifying and warning of extreme gap and jet wind events at all latitudes. e) identifying the current location of frontal systems and high and low pressure centers. f) improving coastal surf and swell forecasts Much has been learned about the importance and utility of satellite OSVW data in operational weather forecasting and warning by exploiting OSVW research satellites in near real-time. Since December 1999 when first data from QuikSCAT scatterometer became available in near real time NOAA operations have been benefiting from ASCAT scatterometer observations on MetOp-A and B, Indian OSCAT scatterometer on OceanSat-3 and lately NASA's RapidScat mission on International Space Station. With oceans comprising over 70 percent of the earth's surface, the impacts of these data have been tremendous in serving society's needs for weather and water information and in supporting the nation's commerce with information for safe, efficient, and environmentally sound transportation and coastal preparedness. The satellite OSVW experience that has been gained over the past decade by users in the operational weather community allows for realistic operational OSVW requirements to be properly stated for future missions. Successful model of transitioning research data into operation implemented by Ocean Winds Team in NOAA's NESDIS/STAR office and subsequent data impacts will be presented and discussed.

  16. Characterizing Tropospheric Winds by Combining MISR Cloud-Track and QuikSCAT Surface Wind Vectors

    NASA Astrophysics Data System (ADS)

    Davies, R.; Garay, M. J.; Moroney, C. M.; Liu, W. T.

    2007-12-01

    Numerous studies have found that the inclusion of wind observations results in a significantly greater improvement in operational weather forecasts compared to the addition of temperature or pressure observations alone. However, global tropospheric wind measurements are only available from 12-hourly rawinsonde launches from selected locations, primarily over land. For years the world's oceans were "data voids" in terms of wind measurements. Only recently have satellites begun to fill this gap. The SeaWinds scatterometer on the QuikSCAT satellite obtains winds referenced to 10 meters above the surface over the global oceans under nearly all weather conditions. The wind speed and direction data from QuikSCAT have been extensively tested against surface observations and are of such quality that these data are routinely assimilated into numerical weather prediction models run by both the National Center for Environmental Prediction (NCEP) and the European Centre for Medium Range Weather Forecasting (ECMWF). However, scatterometer data only provide wind information near the ocean surface. This information can be complemented with satellite cloud-track winds that provide information about winds in the free troposphere over the ocean, as well as over land, where scatterometer data are not available. In particular, the height resolved cloud motion vectors from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on the NASA EOS Terra satellite yield wind speeds for clouds at altitudes less than approximately 2.5 km that are shown to compare favorably with the QuikSCAT winds globally. In addition, the direction of the MISR winds is similar to the QuikSCAT wind vectors when compared on the same basis. The synergistic use of these two sets of wind observations has the potential to make possible a variety of new studies: from improved forecast and climate model validation; to increased understanding of tropospheric water vapor transport; to observations of the coupling

  17. Ocean Surface Vector Wind: Research Challenges and Operational Opportunities

    NASA Technical Reports Server (NTRS)

    Halpern, David

    2012-01-01

    The atmosphere and ocean are joined together over seventy percent of Earth, with ocean surface vector wind (OSVW) stress one of the linkages. Satellite OSVW measurements provide estimates of wind divergence at the bottom of the atmosphere and wind stress curl at the top of the ocean; both variables are critical for weather and climate applications. As is common with satellite measurements, a multitude of OSVW data products exist for each currently operating satellite instrument. In 2012 the Joint Technical Commission on Oceanography and Marine Meteorology (JCOMM) launched an initiative to coordinate production of OSVW data products to maximize the impact and benefit of existing and future OSVW measurements in atmospheric and oceanic applications. This paper describes meteorological and oceanographic requirements for OSVW data products; provides an inventory of unique data products to illustrate that the challenge is not the production of individual data products, but the generation of harmonized datasets for analysis and synthesis of the ensemble of data products; and outlines a vision for JCOMM, in partnership with other international groups, to assemble an international network to share ideas, data, tools, strategies, and deliverables to improve utilization of satellite OSVW data products for research and operational applications.

  18. Measurements of Seasonal Changes in Saturn's Zonal Wind and Vertical Wind Shear between 2004 and 2016 from Cassini ISS Images

    NASA Astrophysics Data System (ADS)

    Blalock, John J.; Sayanagi, Kunio M.; Ingersoll, Andrew P.; Dyudina, Ulyana A.; Ewald, Shawn P.

    2016-10-01

    We present updated zonal wind measurements of Saturn using Cassini ISS images between 2004 and 2016. In addition, we present measurements of the vertical wind shear between the cloud levels sensed in the near-infrared continuum band at 750 nm (CB2 filter) and the methane bands at 727 and 889 nm (MT2 and MT3 filters). We previously reported that there may be small seasonal changes in Saturn's zonal wind profile but it was inconclusive due to measurement uncertainties. In our previous reports, we used the zonal standard deviation of the wind vectors as a proxy for the measurement uncertainty. However, zonal standard deviation contains contributions from both real spatial variations in the wind speed as well as uncertainties in the measurements. This raised a difficulty in distinguishing small, real changes in the wind field from the uncertainties in the measurement. We have developed a technique which isolates real spatial variations from measurement uncertainties by analyzing the correlation fields produced in the two-dimensional Correlation Imaging Velocimetry (CIV) cloud-tracking wind measurement method. In our new method, for each single wind vector measurement, we fit an ellipse to the correlation threshold contour, and define it as the uncertainty ellipse of each wind vector. The advantage of our method is that it allows quantification of the anisotropic uncertainty components of each single wind vector, i.e., using the uncertainty ellipse, we deduce the northward, southward, eastward and westward uncertainties for each wind vector from the correlation peak. Comparing the uncertainty values of each wind vector to the zonal standard deviation of all wind vectors at each latitude allows us to decouple the real spatial variations in the wind from the measurement uncertainties. Using this technique, our measurements show small seasonal variations in Saturn's zonal wind profile as well as the vertical wind shear. As a next step, we plan to apply our uncertainty

  19. Single-Vector Calibration of Wind-Tunnel Force Balances

    NASA Technical Reports Server (NTRS)

    Parker, P. A.; DeLoach, R.

    2003-01-01

    An improved method of calibrating a wind-tunnel force balance involves the use of a unique load application system integrated with formal experimental design methodology. The Single-Vector Force Balance Calibration System (SVS) overcomes the productivity and accuracy limitations of prior calibration methods. A force balance is a complex structural spring element instrumented with strain gauges for measuring three orthogonal components of aerodynamic force (normal, axial, and side force) and three orthogonal components of aerodynamic torque (rolling, pitching, and yawing moments). Force balances remain as the state-of-the-art instrument that provide these measurements on a scale model of an aircraft during wind tunnel testing. Ideally, each electrical channel of the balance would respond only to its respective component of load, and it would have no response to other components of load. This is not entirely possible even though balance designs are optimized to minimize these undesirable interaction effects. Ultimately, a calibration experiment is performed to obtain the necessary data to generate a mathematical model and determine the force measurement accuracy. In order to set the independent variables of applied load for the calibration 24 NASA Tech Briefs, October 2003 experiment, a high-precision mechanical system is required. Manual deadweight systems have been in use at Langley Research Center (LaRC) since the 1940s. These simple methodologies produce high confidence results, but the process is mechanically complex and labor-intensive, requiring three to four weeks to complete. Over the past decade, automated balance calibration systems have been developed. In general, these systems were designed to automate the tedious manual calibration process resulting in an even more complex system which deteriorates load application quality. The current calibration approach relies on a one-factor-at-a-time (OFAT) methodology, where each independent variable is

  20. Two-Look Polarimetric (2LP) Microwave Radiometers for Ocean Vector Wind Retrieval

    NASA Astrophysics Data System (ADS)

    Wentz, F. J.; Hilburn, K. A.; Meissner, T.; Brown, S. E.

    2014-12-01

    This talk discusses the future utilization of two-look polarimetric (2LP) microwave radiometers for measuring the ocean surface wind vector. Potentially, these 2LP satellite radiometers offer two advantages over conventional scatterometers: unambiguous wind vector retrievals and low-cost. One concept for a 2LP radiometer is being developed by JPL and is called the Compact Ocean Wind Vector Radiometer (COWVR). A space demonstration of COWVR is planned for 2016 timeframe. To explore the potential of 2LP radiometers, we use the 11 years of WindSat observations as a testbed. We only use that portion of the WindSat swath that has both fore and aft observations. WindSat provides fully polarimetric observations (all four Stokes parameters) at 11, 19, and 37 GHz. This represents 12 independent channels for each of the two azimuth directions. A wind vector retrieval algorithm is developed to fully utilize this wide assortment of information. Since this analysis is based on actual observations, it provides a realistic picture of what to expect from future 2LP radiometers. To our knowledge, this is the first time that the combination of WindSat's fore and aft observations has been fully utilized for wind vector retrievals. In our talk we compare the 2LP wind vector retrieval performance with that of single-look polarimetric radiometers (i.e., WindSat standard product) and scatterometers. We provide basic statistics from a triple collocation between winds from WindSat, QuikScat, and NDBC/PMEL ocean moored buoys. The statistics include the standard deviation of the first ranked ambiguity direction, skill rate, and number of ambiguities. All available data from the common period of operation between WindSat and QuikScat (2003-2009) are used. We characterize the wind direction accuracy as a function of wind speed, and show how 2LP retrievals are able to extend the wind vector accuracy to lower wind speeds than previously considered possible for radiometers.

  1. Vector control of wind turbine on the basis of the fuzzy selective neural net*

    NASA Astrophysics Data System (ADS)

    Engel, E. A.; Kovalev, I. V.; Engel, N. E.

    2016-04-01

    An article describes vector control of wind turbine based on fuzzy selective neural net. Based on the wind turbine system’s state, the fuzzy selective neural net tracks an maximum power point under random perturbations. Numerical simulations are accomplished to clarify the applicability and advantages of the proposed vector wind turbine’s control on the basis of the fuzzy selective neuronet. The simulation results show that the proposed intelligent control of wind turbine achieves real-time control speed and competitive performance, as compared to a classical control model with PID controllers based on traditional maximum torque control strategy.

  2. A Novel Empirical Mode Decomposition With Support Vector Regression for Wind Speed Forecasting.

    PubMed

    Ren, Ye; Suganthan, Ponnuthurai Nagaratnam; Srikanth, Narasimalu

    2016-08-01

    Wind energy is a clean and an abundant renewable energy source. Accurate wind speed forecasting is essential for power dispatch planning, unit commitment decision, maintenance scheduling, and regulation. However, wind is intermittent and wind speed is difficult to predict. This brief proposes a novel wind speed forecasting method by integrating empirical mode decomposition (EMD) and support vector regression (SVR) methods. The EMD is used to decompose the wind speed time series into several intrinsic mode functions (IMFs) and a residue. Subsequently, a vector combining one historical data from each IMF and the residue is generated to train the SVR. The proposed EMD-SVR model is evaluated with a wind speed data set. The proposed EMD-SVR model outperforms several recently reported methods with respect to accuracy or computational complexity.

  3. Compensating for volume and vector averaging biases in lidar wind speed measurements

    NASA Astrophysics Data System (ADS)

    Clive, Peter J. M.

    2008-10-01

    A number of vector and volume averaging considerations arise in relation to remote sensing, and in particular, Lidar. 1) Remote sensing devices obtain vector averages. These values are often compared to the scalar averages associated with cup anemometry. The magnitude of a vector average is less than or equal to the scalar average obtained over the same period. The use of Lidars in wind power applications has entailed the estimation of scalar averages by vector averages and vice versa. The relationship between the two kinds of average must therefore be understood. It is found that the ratio of the averages depends upon wind direction variability according to a Bessel function of the standard deviation of the wind direction during the averaging interval. 2) The finite probe length of remote sensing devices also incurs a volume averaging bias when wind shear is non-linear. The sensitivity of the devices to signals from a range of heights produces volume averages which will be representative of wind speeds at heights within that range. One can distinguish between the effective or apparent height the measured wind speeds represent as a result of volume averaging bias, and the configuration height at which the device has been set to measure wind speeds. If the wind shear is described by a logarithmic wind profile the apparent height is found to depend mainly on simple geometrical arguments concerning configuration height and probe length and is largely independent of the degree of wind shear. 3) The restriction of the locus of points at which radial velocity measurements are made to the circumference of a horizontally oriented disc at a particular height is seen to introduce ambiguity into results when dealing with wind vector fields which are not irrotational.

  4. Compensation of vector and volume averaging bias in lidar wind speed measurements

    NASA Astrophysics Data System (ADS)

    Clive, P. J. M.

    2008-05-01

    A number of vector and volume averaging considerations arise in relation to remote sensing, and in particular, Lidar. 1) Remote sensing devices obtain vector averages. These values are often compared to the scalar averages associated with cup anemometry. The magnitude of a vector average is less than or equal to the scalar average obtained over the same period. The use of Lidars in wind power applications has entailed the estimation of scalar averages by vector averages and vice versa. The relationship between the two kinds of average must therefore be understood. It is found that the ratio of the averages depends upon wind direction variability according to a Bessel function of the standard deviation of the wind direction during the averaging interval. 2) The finite probe length of remote sensing devices also incurs a volume averaging bias when wind shear is non-linear. The sensitivity of the devices to signals from a range of heights produces volume averages which will be representative of wind speeds at heights within that range. One can distinguish between the effective or apparent height the measured wind speeds represent as a result of volume averaging bias, and the configuration height at which the device has been set to measure wind speeds. If the wind shear is described by a logarithmic wind profile the apparent height is found to depend mainly on simple geometrical arguments concerning configuration height and probe length and is largely independent of the degree of wind shear. 3) The restriction of the locus of points at which radial velocity measurements are made to the circumference of a horizontally oriented disc at a particular height is seen to introduce ambiguity into results when dealing with wind vector fields which are not irrotational.

  5. Wind changes above warm Agulhas Current eddies

    NASA Astrophysics Data System (ADS)

    Rouault, M.; Verley, P.; Backeberg, B.

    2016-04-01

    , change in wind speed above eddies was masked by a large-scale synoptic wind speed deceleration/acceleration affecting parts of the eddies.

  6. Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA

    USGS Publications Warehouse

    Griffiths, P.G.; Webb, R.H.; Fisher, M.; Muth, A.

    2009-01-01

    Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind directions are generally defined in this valley, the wind field has complex interactions with local topography and becomes more variable with distance from the pass. Local, dominant wind directions are preserved by growth patterns of Larrea tridentata (creosote bush), a shrub characteristic of the hot North American deserts, and ventifacts. Exceptionally long-lived, Larrea has the potential to preserve wind direction over centuries to millennia, shaped by the abrasive pruning of windward branches and the persistent training of leeward branches. Wind direction preserved in Larrea individuals and clones was mapped at 192 locations. Compared with wind data from three weather stations, Larrea vectors effectively reflect annual prevailing winds. Ventifacts measured at 24 locations record winds 10° more westerly than Larrea and appear to reflect the direction of the most erosive winds. Based on detailed mapping of local wind directions as preserved in Larrea, only the northern half of the Mission-Morongo Creek floodplain is likely to supply sand to protected U. inornata habitat in the Willow Hole ecological reserve.

  7. Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA

    NASA Astrophysics Data System (ADS)

    Griffiths, Peter G.; Webb, Robert H.; Fisher, Mark; Muth, Allan

    Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind directions are generally defined in this valley, the wind field has complex interactions with local topography and becomes more variable with distance from the pass. Local, dominant wind directions are preserved by growth patterns of Larrea tridentata (creosote bush), a shrub characteristic of the hot North American deserts, and ventifacts. Exceptionally long-lived, Larrea has the potential to preserve wind direction over centuries to millennia, shaped by the abrasive pruning of windward branches and the persistent training of leeward branches. Wind direction preserved in Larrea individuals and clones was mapped at 192 locations. Compared with wind data from three weather stations, Larrea vectors effectively reflect annual prevailing winds. Ventifacts measured at 24 locations record winds 10° more westerly than Larrea and appear to reflect the direction of the most erosive winds. Based on detailed mapping of local wind directions as preserved in Larrea, only the northern half of the Mission-Morongo Creek floodplain is likely to supply sand to protected U. inornata habitat in the Willow Hole ecological reserve.

  8. Effects of Climate and Climate Change on Vectors and Vector-Borne Diseases: Ticks Are Different.

    PubMed

    Ogden, Nick H; Lindsay, L Robbin

    2016-08-01

    There has been considerable debate as to whether global risk from vector-borne diseases will be impacted by climate change. This has focussed on important mosquito-borne diseases that are transmitted by the vectors from infected to uninfected humans. However, this debate has mostly ignored the biological diversity of vectors and vector-borne diseases. Here, we review how climate and climate change may impact those most divergent of arthropod disease vector groups: multivoltine insects and hard-bodied (ixodid) ticks. We contrast features of the life cycles and behaviour of these arthropods, and how weather, climate, and climate change may have very different impacts on the spatiotemporal occurrence and abundance of vectors, and the pathogens they transmit.

  9. Effectiveness of Changing Wind Turbine Cut-in Speed to Reduce Bat Fatalities at Wind Facilities

    SciTech Connect

    Huso, Manuela M. P.; Hayes, John P.

    2009-04-01

    This report details an experiment on the effectiveness of changing wind turbine cut-in speed on reducing bat fatality from wind turbines at the Casselman Wind Project in Somerset County, Pennsylvania.

  10. Declining Prevalence of Disease Vectors Under Climate Change.

    PubMed

    Escobar, Luis E; Romero-Alvarez, Daniel; Leon, Renato; Lepe-Lopez, Manuel A; Craft, Meggan E; Borbor-Cordova, Mercy J; Svenning, Jens-Christian

    2016-12-16

    More than half of the world population is at risk of vector-borne diseases including dengue fever, chikungunya, zika, yellow fever, leishmaniasis, chagas disease, and malaria, with highest incidences in tropical regions. In Ecuador, vector-borne diseases are present from coastal and Amazonian regions to the Andes Mountains; however, a detailed characterization of the distribution of their vectors has never been carried out. We estimate the distribution of 14 vectors of the above vector-borne diseases under present-day and future climates. Our results consistently suggest that climate warming is likely threatening some vector species with extinction, locally or completely. These results suggest that climate change could reduce the burden of specific vector species. Other vector species are likely to shift and constrain their geographic range to the highlands in Ecuador potentially affecting novel areas and populations. These forecasts show the need for development of early prevention strategies for vector species currently absent in areas projected as suitable under future climate conditions. Informed interventions could reduce the risk of human exposure to vector species with distributional shifts, in response to current and future climate changes. Based on the mixed effects of future climate on human exposure to disease vectors, we argue that research on vector-borne diseases should be cross-scale and include climatic, demographic, and landscape factors, as well as forces facilitating disease transmission at fine scales.

  11. Declining Prevalence of Disease Vectors Under Climate Change

    PubMed Central

    Escobar, Luis E.; Romero-Alvarez, Daniel; Leon, Renato; Lepe-Lopez, Manuel A.; Craft, Meggan E.; Borbor-Cordova, Mercy J.; Svenning, Jens-Christian

    2016-01-01

    More than half of the world population is at risk of vector-borne diseases including dengue fever, chikungunya, zika, yellow fever, leishmaniasis, chagas disease, and malaria, with highest incidences in tropical regions. In Ecuador, vector-borne diseases are present from coastal and Amazonian regions to the Andes Mountains; however, a detailed characterization of the distribution of their vectors has never been carried out. We estimate the distribution of 14 vectors of the above vector-borne diseases under present-day and future climates. Our results consistently suggest that climate warming is likely threatening some vector species with extinction, locally or completely. These results suggest that climate change could reduce the burden of specific vector species. Other vector species are likely to shift and constrain their geographic range to the highlands in Ecuador potentially affecting novel areas and populations. These forecasts show the need for development of early prevention strategies for vector species currently absent in areas projected as suitable under future climate conditions. Informed interventions could reduce the risk of human exposure to vector species with distributional shifts, in response to current and future climate changes. Based on the mixed effects of future climate on human exposure to disease vectors, we argue that research on vector-borne diseases should be cross-scale and include climatic, demographic, and landscape factors, as well as forces facilitating disease transmission at fine scales. PMID:27982119

  12. Declining Prevalence of Disease Vectors Under Climate Change

    NASA Astrophysics Data System (ADS)

    Escobar, Luis E.; Romero-Alvarez, Daniel; Leon, Renato; Lepe-Lopez, Manuel A.; Craft, Meggan E.; Borbor-Cordova, Mercy J.; Svenning, Jens-Christian

    2016-12-01

    More than half of the world population is at risk of vector-borne diseases including dengue fever, chikungunya, zika, yellow fever, leishmaniasis, chagas disease, and malaria, with highest incidences in tropical regions. In Ecuador, vector-borne diseases are present from coastal and Amazonian regions to the Andes Mountains; however, a detailed characterization of the distribution of their vectors has never been carried out. We estimate the distribution of 14 vectors of the above vector-borne diseases under present-day and future climates. Our results consistently suggest that climate warming is likely threatening some vector species with extinction, locally or completely. These results suggest that climate change could reduce the burden of specific vector species. Other vector species are likely to shift and constrain their geographic range to the highlands in Ecuador potentially affecting novel areas and populations. These forecasts show the need for development of early prevention strategies for vector species currently absent in areas projected as suitable under future climate conditions. Informed interventions could reduce the risk of human exposure to vector species with distributional shifts, in response to current and future climate changes. Based on the mixed effects of future climate on human exposure to disease vectors, we argue that research on vector-borne diseases should be cross-scale and include climatic, demographic, and landscape factors, as well as forces facilitating disease transmission at fine scales.

  13. Surface Wind Vector and Rain Rate Observation Capability of Future Hurricane Imaging Radiometer (HIRAD)

    NASA Technical Reports Server (NTRS)

    Miller, Timothy; Atlas, Robert; Bailey, M. C.; Black, Peter; El-Nimri, Salem; Hood, Robbie; James, Mark; Johnson, James; Jones, Linwood; Ruf, Christopher; Uhlhorn, Eric

    2009-01-01

    The Hurricane Imaging Radiometer (HIRAD) is the next-generation Stepped Frequency Microwave Radiometer (SFMR), and it will offer the capability of simultaneous wide-swath observations of both extreme ocean surface wind vector and strong precipitation from either aircraft (including UAS) or satellite platforms. HIRAD will be a compact, lightweight, low-power instrument with no moving parts that will produce valid wind observations under hurricane conditions when existing microwave sensors (radiometers or scatterometers) are hindered by precipitation. The SFMR i s a proven aircraft remote sensing system for simultaneously observing extreme ocean surface wind speeds and rain rates, including those of major hurricane intensity. The proposed HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer technology. The first version of the instrument will be a single polarization system for wind speed and rain rate, with a dual-polarization system to follow for wind vector capability. This sensor will operate over 4-7 GHz (C-band frequencies) where the required tropical cyclone remote sensing physics has been validated by both SFMR and WindSat radiometers. HIRAD incorporates a unique, technologically advanced array antenna and several other technologies successfully demonstrated by NASA s Instrument Incubator Program. A brassboard (laboratory) version of the instrument has been completed and successfully tested in a test chamber. Development of the aircraft instrument is underway, with flight testing planned for the fall of 2009. Preliminary Observing System Simulation Experiments (OSSEs) show that HIRAD will have a significant positive impact on surface wind analyses as either a new aircraft or satellite sensor. New off-nadir data collected in 2008 by SFMR that affirms the ability of this measurement technique to obtain wind speed data at non-zero incidence angle will

  14. A vector auto-regressive model for onshore and offshore wind synthesis incorporating meteorological model information

    NASA Astrophysics Data System (ADS)

    Hill, D.; Bell, K. R. W.; McMillan, D.; Infield, D.

    2014-05-01

    The growth of wind power production in the electricity portfolio is striving to meet ambitious targets set, for example by the EU, to reduce greenhouse gas emissions by 20% by 2020. Huge investments are now being made in new offshore wind farms around UK coastal waters that will have a major impact on the GB electrical supply. Representations of the UK wind field in syntheses which capture the inherent structure and correlations between different locations including offshore sites are required. Here, Vector Auto-Regressive (VAR) models are presented and extended in a novel way to incorporate offshore time series from a pan-European meteorological model called COSMO, with onshore wind speeds from the MIDAS dataset provided by the British Atmospheric Data Centre. Forecasting ability onshore is shown to be improved with the inclusion of the offshore sites with improvements of up to 25% in RMS error at 6 h ahead. In addition, the VAR model is used to synthesise time series of wind at each offshore site, which are then used to estimate wind farm capacity factors at the sites in question. These are then compared with estimates of capacity factors derived from the work of Hawkins et al. (2011). A good degree of agreement is established indicating that this synthesis tool should be useful in power system impact studies.

  15. Global Change and Human Vulnerability to Vector-Borne Diseases

    PubMed Central

    Sutherst, Robert W.

    2004-01-01

    Global change includes climate change and climate variability, land use, water storage and irrigation, human population growth and urbanization, trade and travel, and chemical pollution. Impacts on vector-borne diseases, including malaria, dengue fever, infections by other arboviruses, schistosomiasis, trypanosomiasis, onchocerciasis, and leishmaniasis are reviewed. While climate change is global in nature and poses unknown future risks to humans and natural ecosystems, other local changes are occurring more rapidly on a global scale and are having significant effects on vector-borne diseases. History is invaluable as a pointer to future risks, but direct extrapolation is no longer possible because the climate is changing. Researchers are therefore embracing computer simulation models and global change scenarios to explore the risks. Credible ranking of the extent to which different vector-borne diseases will be affected awaits a rigorous analysis. Adaptation to the changes is threatened by the ongoing loss of drugs and pesticides due to the selection of resistant strains of pathogens and vectors. The vulnerability of communities to the changes in impacts depends on their adaptive capacity, which requires both appropriate technology and responsive public health systems. The availability of resources in turn depends on social stability, economic wealth, and priority allocation of resources to public health. PMID:14726459

  16. Sensitivity of Southern Ocean circulation to wind stress changes: Role of relative wind stress

    NASA Astrophysics Data System (ADS)

    Munday, D. R.; Zhai, X.

    2015-11-01

    The influence of different wind stress bulk formulae on the response of the Southern Ocean circulation to wind stress changes is investigated using an idealised channel model. Surface/mixed layer properties are found to be sensitive to the use of the relative wind stress formulation, where the wind stress depends on the difference between the ocean and atmosphere velocities. Previous work has highlighted the surface eddy damping effect of this formulation, which we find leads to increased circumpolar transport. Nevertheless the transport due to thermal wind shear does lose sensitivity to wind stress changes at sufficiently high wind stress. In contrast, the sensitivity of the meridional overturning circulation is broadly the same regardless of the bulk formula used due to the adiabatic nature of the relative wind stress damping. This is a consequence of the steepening of isopycnals offsetting the reduction in eddy diffusivity in their contribution to the eddy bolus overturning, as predicted using a residual mean framework.

  17. Measurements of wind vectors, eddy momentum transports, and energy conversions in Jupiter's atmosphere from Voyager 1 images

    NASA Technical Reports Server (NTRS)

    Beebe, R. F.; Ingersoll, A. P.; Hunt, G. E.; Muller, J.-P.; Mitchell, J. L.

    1980-01-01

    Voyager 1 narrow-angle images were used to obtain displacements of features down to 100 to 200 km in size over intervals of 10 hours. A global map of velocity vectors and longitudinally averaged zonal wind vectors as functions of the latitude, is presented and discussed

  18. The Alignment of the Mean Wind and Stress Vectors in the Unstable Surface Layer

    NASA Astrophysics Data System (ADS)

    Bernardes, M.; Dias, N. L.

    2010-01-01

    A significant non-alignment between the mean horizontal wind vector and the stress vector was observed for turbulence measurements both above the water surface of a large lake, and over a land surface (soybean crop). Possible causes for this discrepancy such as flow distortion, averaging times and the procedure used for extracting the turbulent fluctuations (low-pass filtering and filter widths etc.), were dismissed after a detailed analysis. Minimum averaging times always less than 30 min were established by calculating ogives, and error bounds for the turbulent stresses were derived with three different approaches, based on integral time scales (first-crossing and lag-window estimates) and on a bootstrap technique. It was found that the mean absolute value of the angle between the mean wind and stress vectors is highly related to atmospheric stability, with the non-alignment increasing distinctively with increasing instability. Given a coordinate rotation that aligns the mean wind with the x direction, this behaviour can be explained by the growth of the relative error of the u- w component with instability. As a result, under more unstable conditions the u- w and the v- w components become of the same order of magnitude, and the local stress vector gives the impression of being non-aligned with the mean wind vector. The relative error of the v- w component is large enough to make it undistinguishable from zero throughout the range of stabilities. Therefore, the standard assumptions of Monin-Obukhov similarity theory hold: it is fair to assume that the v- w stress component is actually zero, and that the non-alignment is a purely statistical effect. An analysis of the dimensionless budgets of the u- w and the v- w components confirms this interpretation, with both shear and buoyant production of u- w decreasing with increasing instability. In the v- w budget, shear production is zero by definition, while buoyancy displays very low-intensity fluctuations around

  19. Evaluation and Validation of Operational RapidScat Ocean Surface Vector Winds

    NASA Astrophysics Data System (ADS)

    Chang, Paul; Jelenak, Zorana; Soisuvarn, Seubson; Said, Faozi; Sienkiewicz, Joseph; Brennan, Michael

    2015-04-01

    NASA launched RapidScat to the International Space Station (ISS) on September 21, 2014 on a two-year mission to support global monitoring of ocean winds for improved weather forecasting and climate studies. The JPL-developed space-based scatterometer is conically scanning and operates at ku-band (13.4 GHz) similar to QuikSCAT. The ISS-RapidScat's measurement swath is approximately 900 kilometers and covers the majority of the ocean between 51.6 degrees north and south latitude (approximately from north of Vancouver, Canada, to the southern tip of Patagonia) in 48 hours. RapidScat data are currently being posted at a spacing of 25 kilometers, but a version to be released in the near future will improve the postings to 12.5 kilometers. RapidScat ocean surface wind vector data are being provided in near real-time to NOAA, and other operational users such as the U.S. Navy, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the Indian Space Research Organisation (ISRO) and the Royal Netherlands Meteorological Institute (KNMI). The quality of the RapidScat OSVW data are assessed by collocating the data in space and time with "truth" data. Typically "truth" data will include, but are not limited to, the NWS global forecast model analysis (GDAS) fields, buoys, ASCAT, WindSat, AMSR-2, and aircraft measurements during hurricane and winter storm experiment flights. The standard statistical analysis used for satellite microwave wind sensors will be utilized to characterize the RapidScat wind vector retrievals. The global numerical weather prediction (NWP) models are a convenient source of "truth" data because they are available 4 times/day globally which results in the accumulation of a large number of collocations over a relatively short amount of time. The NWP model fields are not "truth" in the same way an actual observation would be, however, as long as there are no systematic errors in the NWP model output the collocations will

  20. The effect of the arbitrary level assignment of satellite cloud motion wind vectors on wind analyses in the pre-thunderstorm environment

    NASA Technical Reports Server (NTRS)

    Peslen, C. A.; Koch, S. E.; Uccellini, L. W.

    1986-01-01

    The impact of satellite-derived cloud motion vectors on SESAME rawinsonde wind fields was studied in two separate cases. The effect of wind and moisture gradients on the arbitrary assignment of the satellite data is assessed to coordinate surfaces in a severe storm environment marked by strong vertical wind shear. Objective analyses of SESAME rawinsonde winds and combined winds are produced and differences between these two analyzed fields are used to make an assessment of coordinate level choice. It is shown that the standard method of arbitrarily assigning wind vectors to a low level coordinate surface yields systematic differences between the rawinsonde and combined wind analyses. Arbitrary assignment of cloud motions to the 0.9 sigma surface produces smaller differences than assignment to the 825 mb pressure surface. Systematic differences occur near moisture discontinuities and in regions of horizontal and vertical wind shears. The differences between the combined and SESAME wind fields are made smallest by vertically interpolating cloud motions to either a pressure or sigma surface.

  1. The effect of the arbitrary level assignment of satellite cloud motion wind vectors on wind analyses in the pre-thunderstorm environment

    NASA Technical Reports Server (NTRS)

    Peslen, C. A.; Koch, S. E.; Uccellini, L. W.

    1985-01-01

    The impact of satellite-derived cloud motion vectors on SESAME rawinsonde wind fields was studied in two separate cases. The effect of wind and moisture gradients on the arbitrary assignment of the satellite data is assessed to coordinate surfaces in a severe storm environment marked by strong vertical wind shear. Objective analyses of SESAME rawinsonde winds and combined winds are produced and differences between these two analyzed fields are used to make an assessment of coordinate level choice. It is shown that the standard method of arbitrarily assigning wind vectors to a low level coordinate surface yields systematic differences between the rawinsonde and combined wind analyses. Arbitrary assignment of cloud motions to the 0.9 sigma surface produces smaller differences than assignment to the 825 mb pressure surface. Systematic differences occur near moisture discontinuities and in regions of horizontal and vertical wind shears. The differences between the combined and SESAME wind fields are made smallest by vertically interpolating cloud motions to either a pressure or sigma surface.

  2. Wave-Vector Dependence of Magnetic-Turbulence Spectra in the Solar Wind

    SciTech Connect

    Narita, Y.; Glassmeier, K.-H.; Sahraoui, F.; Goldstein, M. L.

    2010-04-30

    Using four-point measurements of the Cluster spacecraft, the energy distribution was determined for magnetic field fluctuations in the solar wind directly in the three-dimensional wave-vector domain in the range |k|{<=}1.5x10{sup -3} rad/km. The energy distribution exhibits anisotropic features characterized by a prominently extended structure perpendicular to the mean field preferring the ecliptic north direction and also by a moderately extended structure parallel to the mean field. From the three-dimensional energy distribution wave vector anisotropy is estimated with respect to directions parallel and perpendicular to the mean magnetic field, and the result suggests the dominance of quasi-two-dimensional turbulence toward smaller spatial scales.

  3. Effects of Changing Atmospheric Conditions on Wind Turbine Performance (Poster)

    SciTech Connect

    Clifton, A.

    2012-12-01

    Multi-megawatt, utility-scale wind turbines operate in turbulent and dynamic winds that impact turbine performance in ways that are gradually becoming better understood. This poster presents a study made using a turbulent flow field simulator (TurbSim) and a Turbine aeroelastic simulator (FAST) of the response of a generic 1.5 MW wind turbine to changing inflow. The turbine power output is found to be most sensitive to wind speed and turbulence intensity, but the relationship depends on the wind speed with respect to the turbine's rated wind speed. Shear is found to be poorly correlated to power. A machine learning method called 'regression trees' is used to create a simple model of turbine performance that could be used as part of the wind resource assessment process. This study has used simple flow fields and should be extended to more complex flows, and validated with field observations.

  4. Wind farm induced changes in wind speed and surface fluxes over the North Sea

    NASA Astrophysics Data System (ADS)

    Chatterjee, Fabien; van Lipzig, Nicole; Meyers, Johan

    2016-04-01

    Offshore wind farm deployment in the North Sea is foreseen to expand dramatically in the coming years. The strong expansion of offshore wind parks is likely to affect the regional climatology on the North Sea. We assess this impact by conducting a regional climate model simulation over future wind farms built near the German coast. In order to achieve this, the wind farm parameterisation of Fitch et al. 2012, where wind farms are parameterised as elevated sources of turbulent kinetic energy and sinks of momentum ( Blahak et al 2010 and Fitch et al 2012) is implemented in COSMO-CLM at a 1.5 km resolution. As a first step, COSMO-CLM's ability to reproduce wind profiles over the North Sea is evaluated using wind speed data from the FINO1 meteorological mast, toghether with QuikScat scatterometer data, for a time period of 2000-2008. Subsequently, the impact of windfarms on the regional climate over a period of ten years (1999-2008) is assessed. A large scale wind farm can create wakes which depending on the wind direction could affect the power production of a neighbouring farm. Furthermore, wind farms decelerate the flow and create a vertical circulation in the inflow region. As a result, changes in vertical fluxes of moisture are observed. This leads to enhanced low level cloud cover which may trigger changes in precipitation.

  5. Thrust vectoring of an electric solar wind sail with a realistic sail shape

    NASA Astrophysics Data System (ADS)

    Toivanen, P.; Janhunen, P.

    2017-02-01

    The shape of a rotating electric solar wind sail under the centrifugal force and solar wind dynamic pressure is modeled to address the sail attitude maintenance and thrust vectoring. The sail rig assumes centrifugally stretched main tethers that extend radially outward from the spacecraft in the sail spin plane. Furthermore, the tips of the main tethers host remote units that are connected by auxiliary tethers at the sail rim. Here, we derive the equation of main tether shape and present both a numerical solution and an analytical approximation for the shape as parametrized both by the ratio of the electric sail force to the centrifugal force and the sail orientation with respect to the solar wind direction. The resulting shape is such that near the spacecraft, the roots of the main tethers form a cone, whereas towards the rim, this coning is flattened by the centrifugal force, and the sail is coplanar with the sail spin plane. Our approximation for the sail shape is parametrized only by the tether root coning angle and the main tether length. Using the approximate shape, we obtain the torque and thrust of the electric sail force applied to the sail. As a result, the amplitude of the tether voltage modulation required for the maintenance of the sail attitude is given as a torque-free solution. The amplitude is smaller than that previously obtained for a rigid single tether resembling a spherical pendulum. This implies that less thrusting margin is required for the maintenance of the sail attitude. For a given voltage modulation, the thrust vectoring is then considered in terms of the radial and transverse thrust components.

  6. Corrigendum to "Measuring the 3-D wind vector with a weight-shiftmicrolight aircraft" published in Atmos. Meas. Tech., 4, 1421-1444, 2011

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2011-07-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. We draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty) from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 %) by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %), as well as changes in the aircraft lift (16 %) are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a) A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s-1 at the extremes of a 95 % confidence interval. (b) During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s-1. (c) The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error) of ≈0.4 m s-1 for the horizontal and ≈0.3 m s-1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s-1) or true airspeed (ranging from 23-30 m s-1) is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  7. Climate change and vector-borne diseases: a regional analysis.

    PubMed

    Githeko, A K; Lindsay, S W; Confalonieri, U E; Patz, J A

    2000-01-01

    Current evidence suggests that inter-annual and inter-decadal climate variability have a direct influence on the epidemiology of vector-borne diseases. This evidence has been assessed at the continental level in order to determine the possible consequences of the expected future climate change. By 2100 it is estimated that average global temperatures will have risen by 1.0-3.5 degrees C, increasing the likelihood of many vector-borne diseases in new areas. The greatest effect of climate change on transmission is likely to be observed at the extremes of the range of temperatures at which transmission occurs. For many diseases these lie in the range 14-18 degrees C at the lower end and about 35-40 degrees C at the upper end. Malaria and dengue fever are among the most important vector-borne diseases in the tropics and subtropics; Lyme disease is the most common vector-borne disease in the USA and Europe. Encephalitis is also becoming a public health concern. Health risks due to climatic changes will differ between countries that have developed health infrastructures and those that do not. Human settlement patterns in the different regions will influence disease trends. While 70% of the population in South America is urbanized, the proportion in sub-Saharan Africa is less than 45%. Climatic anomalies associated with the El Niño-Southern Oscillation phenomenon and resulting in drought and floods are expected to increase in frequency and intensity. They have been linked to outbreaks of malaria in Africa, Asia and South America. Climate change has far-reaching consequences and touches on all life-support systems. It is therefore a factor that should be placed high among those that affect human health and survival.

  8. Climate change and vector-borne diseases: a regional analysis.

    PubMed Central

    Githeko, A. K.; Lindsay, S. W.; Confalonieri, U. E.; Patz, J. A.

    2000-01-01

    Current evidence suggests that inter-annual and inter-decadal climate variability have a direct influence on the epidemiology of vector-borne diseases. This evidence has been assessed at the continental level in order to determine the possible consequences of the expected future climate change. By 2100 it is estimated that average global temperatures will have risen by 1.0-3.5 degrees C, increasing the likelihood of many vector-borne diseases in new areas. The greatest effect of climate change on transmission is likely to be observed at the extremes of the range of temperatures at which transmission occurs. For many diseases these lie in the range 14-18 degrees C at the lower end and about 35-40 degrees C at the upper end. Malaria and dengue fever are among the most important vector-borne diseases in the tropics and subtropics; Lyme disease is the most common vector-borne disease in the USA and Europe. Encephalitis is also becoming a public health concern. Health risks due to climatic changes will differ between countries that have developed health infrastructures and those that do not. Human settlement patterns in the different regions will influence disease trends. While 70% of the population in South America is urbanized, the proportion in sub-Saharan Africa is less than 45%. Climatic anomalies associated with the El Niño-Southern Oscillation phenomenon and resulting in drought and floods are expected to increase in frequency and intensity. They have been linked to outbreaks of malaria in Africa, Asia and South America. Climate change has far-reaching consequences and touches on all life-support systems. It is therefore a factor that should be placed high among those that affect human health and survival. PMID:11019462

  9. Impact of Short Interval SMS Digital Data on Wind Vector Determination for a Severe Local Storms Area

    NASA Technical Reports Server (NTRS)

    Peslen, C. A.

    1979-01-01

    The impact of 5 minute interval SMS-2 visible digital image data in analyzing severe local storms is examined using wind vectors derived from cloud tracking on time lapsed sequence of geosynchronous satellite images. The cloud tracking areas are located in the Central Plains, where on 6 May 1975, hail-producing thunderstorms occurred ahead of a well defined dry line. The results demonstrate that satellite-derived wind vectors and their associated divergence fields complement conventional meteorological analyses in describing the conditions preceding severe local storm development.

  10. Solar Wind Change Exchange from the Magnetosheath

    NASA Technical Reports Server (NTRS)

    Snowden, Steve

    2008-01-01

    We report the results of a long (approximately 100 ks) XMM-Newton observation designed to observe solar wind charge exchange emission (SWCX) from Earth's magnetosheath. By luck, the observation took place during a period of minimal solar wind flux so the SWCX emission was also minimal. Never-the-less, there is a significant if not stunning correlation between the observed O VIII count rate and our model for magnetosheath emission. We also report on the observed O VII and O VII emission.

  11. Immunology, climate change and vector-borne diseases.

    PubMed

    Patz, J A; Reisen, W K

    2001-04-01

    Global climate change might expand the distribution of vector-borne pathogens in both time and space, thereby exposing host populations to longer transmission seasons, and immunologically naive populations to newly introduced pathogens. In the African highlands, where cool temperatures limit malaria parasite development, increases in temperature might enhance malaria transmission. St Louis encephalitis viral replication and the length of the transmission season depend upon ambient temperature. Warming temperatures in the American southwest might place at risk migratory, non-immune elderly persons that arrive in early fall to spend the winter. Warm temperatures might intensify or extend the transmission season for dengue fever. Immunologists should examine this interplay between human immunocompetence and vector-borne disease risks in a warmer world.

  12. World Wind Tools Reveal Environmental Change

    NASA Technical Reports Server (NTRS)

    2012-01-01

    Originally developed under NASA's Learning Technologies program as a tool to engage and inspire students, World Wind software was released under the NASA Open Source Agreement license. Honolulu, Hawaii based Intelesense Technologies is one of the companies currently making use of the technology for environmental, public health, and other monitoring applications for nonprofit organizations and Government agencies. The company saved about $1 million in development costs by using the NASA software.

  13. Using support vector machines for anomalous change detonation

    SciTech Connect

    Theiler, James P; Steinwart, Ingo; Llamocca, Daniel

    2010-01-01

    We cast anomalous change detection as a binary classification problem, and use a support vector machine (SVM) to build a detector that does not depend on assumptions about the underlying data distribution. To speed up the computation, our SVM is implemented, in part, on a graphical processing unit. Results on real and simulated anomalous changes are used to compare performance to algorithms which effectively assume a Gaussian distribution. In this paper, we investigate the use of support vector machines (SVMs) with radial basis kernels for finding anomalous changes. Compared to typical applications of SVMs, we are operating in a regime of very low false alarm rate. This means that even for relatively large training sets, the data are quite meager in the regime of operational interest. This drives us to use larger training sets, which in turn places more of a computational burden on the SVM. We initially considered three different approaches to to address the need to work in the very low false alarm rate regime. The first is a standard SVM which is trained at one threshold (where more reliable estimates of false alarm rates are possible) and then re-thresholded for the low false alarm rate regime. The second uses the same thresholding approach, but employs a so-called least squares SVM; here a quadratic (instead of a hinge-based) loss function is employed, and for this model, there are good theoretical arguments in favor of adjusting the threshold in a straightforward manner. The third approach employs a weighted support vector machine, where the weights for the two types of errors (false alarm and missed detection) are automatically adjusted to achieve the desired false alarm rate. We have found in previous experiments (not shown here) that the first two types can in some cases work well, while in other cases they do not. This renders both approaches unreliable for automated change detection. By contrast, the third approach reliably produces good results, but at

  14. Understanding vegetation changes in northern China and Mongolia with change vector analysis.

    PubMed

    Gu, Xiaohe; Li, Weiguo; Wang, Lei

    2016-01-01

    In recent years, a close link between vegetation change and climate change has been established. Vegetation change can be detected with remotely sensed images, especially with normalized difference vegetation index time series records. We used change vector analysis, especially change vector magnitude (CV magnitude), as an indicator to better understand vegetation change. Twenty-one layers of CV magnitude for each 10-day period from April to October have been acquired. Maxima, range, standard deviation, mean, and minima of CV magnitude were obtained and analyzed, identifying 11 regions with different types of vegetation change during different 10-day periods. In addition, the months of maximum CV magnitude were determined to help predict future vegetation change. The following conclusions were drawn: (a) CV magnitude can serve as an indicator to compare vegetation conditions among different years; (b) 11 typical regions were identified in the study area that show vegetation changes between 1999 and 2006;

  15. Future Changes in Surface Winds in the Western U.S. due to Climate Change

    NASA Astrophysics Data System (ADS)

    Snyder, M. A.; O'Brien, T.; Sloan, L. C.

    2008-12-01

    Surface winds are important to both human and natural systems. These winds drive coastal upwelling, which is critical to nearshore ecosystems. Surface winds also play an important role in cooling the coast and inland regions through the thermally driven sea breeze. As Santa Ana winds, they can create extremely hazardous fire weather conditions. Additionally, surface winds are important for wind energy generation and as an alternative to fossil fuels, further development of this resource is expected to grow exponetially. Understanding how winds will change as a function of anthropogenic change climate change will assist in planning for its impact. Using a regional climate model, we examined the impact of future climate change on surface winds in the western U.S. Two pairs of experiments were conducted, using driving data from the IPCC AR4 simulations of the GFDL CM2.1 and the Canadian GCM for the time periods 1968-2000 and 2038- 2070. The IPCC scenario of these runs is the A2 scenario. The regional climate model has a 30km spatial resolution and the domain is centered over the western U.S. and includes the entire coastline of the three coastal U.S. states. Our initial results show significant changes in surface winds between the future and historical cases. The pattern of the change varies along the coast with implications for coastal upwelling and the thermal sea breeze.

  16. Land-use/land-cover change detection using change-vector analysis in posterior probability space

    NASA Astrophysics Data System (ADS)

    Chen, Xuehong; Chen, Jin; Shen, Miaogen; Yang, Wei

    2008-10-01

    Land use/land cover change is an important field in global environmental change research. Remote sensing is a valuable data source from which land use/land cover change information can be extracted efficiently. A number of techniques for accomplishing change detection using satellite imagery have been formulated, applied, and evaluated, which can be generally grouped into two types. (1) Those based on spectral classification of the input data such as post-classification comparison and direct two-date classification; and (2) those based on radiometric change between different acquisition dates. The shortage of type 1 is cumulative error in image classification of an individual date. However, radiometric change approaches has a strict requirement for reliable image radiometry. In light of the above mentioned drawbacks of those two types of change detection methods, this paper presents a new method named change vector analysis in posterior probability space (CVAPS). Change-vector analysis (CVA) is one of the most successful radiometric change-based approaches. CVAPS approach incorporates post-classification comparison method and CVA approach, which is expected to inherit the advantages of two traditional methods and avoid their defects at the same time. CVAPS includes the following four steps. (1) Images in different periods are classified by certain classifier which can provide posterior probability output. Then, the posterior probability can be treated as a vector, the dimension of which is equal to the number of classes. (2) A procedure similar with CVA is employed. Compared with traditional CVA, new method analyzes the change vector in posterior probability space instead of spectral feature space. (3) A semiautomatic method, named Double-Window Flexible Pace Search (DFPS), is employed to determine the threshold of change magnitude. (4) Change category is discriminated by cosines of the change vectors. CVAPS approach was applied and validated by a case study of

  17. Climate change. Climate change and wind intensification in coastal upwelling ecosystems.

    PubMed

    Sydeman, W J; García-Reyes, M; Schoeman, D S; Rykaczewski, R R; Thompson, S A; Black, B A; Bograd, S J

    2014-07-04

    In 1990, Andrew Bakun proposed that increasing greenhouse gas concentrations would force intensification of upwelling-favorable winds in eastern boundary current systems that contribute substantial services to society. Because there is considerable disagreement about whether contemporary wind trends support Bakun's hypothesis, we performed a meta-analysis of the literature on upwelling-favorable wind intensification. The preponderance of published analyses suggests that winds have intensified in the California, Benguela, and Humboldt upwelling systems and weakened in the Iberian system over time scales ranging up to 60 years; wind change is equivocal in the Canary system. Stronger intensification signals are observed at higher latitudes, consistent with the warming pattern associated with climate change. Overall, reported changes in coastal winds, although subtle and spatially variable, support Bakun's hypothesis of upwelling intensification in eastern boundary current systems.

  18. IABC 83/The Winds of Change.

    ERIC Educational Resources Information Center

    International Association of Business Communicators, San Francisco, CA.

    Drawn from a conference focusing on the changing nature of the communication function, the papers in this collection analyze and outline the professional and personal developmental techniques necessary to anticipate and capitalize upon those changes. Among the specific topics discussed in the 32 papers are the following: (1) the techniques and…

  19. Noise model based ν-support vector regression with its application to short-term wind speed forecasting.

    PubMed

    Hu, Qinghua; Zhang, Shiguang; Xie, Zongxia; Mi, Jusheng; Wan, Jie

    2014-09-01

    Support vector regression (SVR) techniques are aimed at discovering a linear or nonlinear structure hidden in sample data. Most existing regression techniques take the assumption that the error distribution is Gaussian. However, it was observed that the noise in some real-world applications, such as wind power forecasting and direction of the arrival estimation problem, does not satisfy Gaussian distribution, but a beta distribution, Laplacian distribution, or other models. In these cases the current regression techniques are not optimal. According to the Bayesian approach, we derive a general loss function and develop a technique of the uniform model of ν-support vector regression for the general noise model (N-SVR). The Augmented Lagrange Multiplier method is introduced to solve N-SVR. Numerical experiments on artificial data sets, UCI data and short-term wind speed prediction are conducted. The results show the effectiveness of the proposed technique.

  20. Atmospheric dynamics: Arctic winds of change

    NASA Astrophysics Data System (ADS)

    Notz, Dirk

    2016-09-01

    The Earth's climate evolves in response to both externally forced changes and internal variability. Now research suggests that both drivers combine to set the pace of Arctic warming caused by large-scale sea-ice loss.

  1. A targeted change-detection procedure by combining change vector analysis and post-classification approach

    NASA Astrophysics Data System (ADS)

    Ye, Su; Chen, Dongmei; Yu, Jie

    2016-04-01

    In remote sensing, conventional supervised change-detection methods usually require effective training data for multiple change types. This paper introduces a more flexible and efficient procedure that seeks to identify only the changes that users are interested in, here after referred to as ;targeted change detection;. Based on a one-class classifier ;Support Vector Domain Description (SVDD);, a novel algorithm named ;Three-layer SVDD Fusion (TLSF); is developed specially for targeted change detection. The proposed algorithm combines one-class classification generated from change vector maps, as well as before- and after-change images in order to get a more reliable detecting result. In addition, this paper introduces a detailed workflow for implementing this algorithm. This workflow has been applied to two case studies with different practical monitoring objectives: urban expansion and forest fire assessment. The experiment results of these two case studies show that the overall accuracy of our proposed algorithm is superior (Kappa statistics are 86.3% and 87.8% for Case 1 and 2, respectively), compared to applying SVDD to change vector analysis and post-classification comparison.

  2. Genomic Changes of Chagas Disease Vector, South America

    PubMed Central

    Dujardin, Jean Pierre; Nicolini, Paula; Caraccio, María Noel; Rose, Virginia; Tellez, Tatiana; Bermúdez, Hernán; Bargues, María Dolores; Mas-Coma, Santiago; O’Connor, José Enrique; Pérez, Ruben

    2004-01-01

    We analyzed the main karyologic changes that have occurred during the dispersion of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4–7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments. PMID:15109410

  3. Winds of Change in Higher Education.

    PubMed

    Ingolfsdottir, Kristin

    2016-12-01

    Recent developments confirm predictions by the IEEE that Massive Open Online Courses (MOOCs) will have extensive impact on the future landscape of higher education. New degree structures are being introduced and awarding of verified MOOC credentials is becoming more widespread, as is recognition of MOOC credits by universities and employers. The question is whether this disruptive influence is being sufficiently used as an incentive for re-evaluation of standard practices and for driving strategic change in higher education.

  4. Methods of Recording Rapid Wind Changes

    NASA Technical Reports Server (NTRS)

    Magnan, A

    1932-01-01

    The purpose of our research was to determine the rapid changes of air currents which impose varying stresses on the wings of airplanes. We attempted to express in figures the turbulence of the air, which perhaps plays some role in the behavior of airplanes in flight, as well as in the realization of certain methods of gliding flight. This is the reason which led us to conceive and develop the experimental equipment (hot-wire anemometer) described herein.

  5. SECULAR CHANGES IN ETA CARINAE'S WIND 1998-2011

    SciTech Connect

    Mehner, Andrea; Davidson, Kris; Humphreys, Roberta M.; Ishibashi, Kazunori; Martin, John C.; Ruiz, Maria Teresa; Walter, Frederick M.

    2012-05-20

    Stellar wind-emission features in the spectrum of eta Carinae have decreased by factors of 1.5-3 relative to the continuum within the last 10 years. We investigate a large data set from several instruments (STIS, GMOS, UVES) obtained between 1998 and 2011 and analyze the progression of spectral changes in direct view of the star, in the reflected polar-on spectra at FOS4, and at the Weigelt knots. We find that the spectral changes occurred gradually on a timescale of about 10 years and that they are dependent on the viewing angle. The line strengths declined most in our direct view of the star. About a decade ago, broad stellar wind-emission features were much stronger in our line-of-sight view of the star than at FOS4. After the 2009 event, the wind-emission line strengths are now very similar at both locations. High-excitation He I and N II absorption lines in direct view of the star strengthened gradually. The terminal velocity of Balmer P Cyg absorption lines now appears to be less latitude dependent, and the absorption strength may have weakened at FOS4. Latitude-dependent alterations in the mass-loss rate and the ionization structure of eta Carinae's wind are likely explanations for the observed spectral changes.

  6. CFOSAT: a new Chinese-French satellite for joint observations of ocean wind vector and directional spectra of ocean waves

    NASA Astrophysics Data System (ADS)

    Hauser, D.; Tison, C.; Amiot, T.; Delaye, L.; Mouche, A.; Guitton, G.; Aouf, L.; Castillan, P.

    2016-05-01

    CFOSAT (the China France Oceanography Satellite) is a joint mission from the Chinese and French Space Agencies, devoted to the observation ocean surface wind and waves so as to improve wind and wave forecast for marine meteorology, ocean dynamics modeling and prediction, climate variability knowledge, fundamental knowledge of surface processes. Currently under Phase D (manufacturing phase), the launch is now planned for mid-2018 the later. The CFOSAT will carry two payloads, both Ku-Band radar: the wave scatterometer (SWIM) and the wind scatterometer (SCAT). Both instruments are based on new concepts with respect to existing satellite-borne wind and wave sensors. Indeed, one of the originalities of CFOSAT is that it will provide simultaneously and in the same zone, the directional spectra of ocean waves and the wind vector. The concept used to measure the directional spectra of ocean waves has never been used from space until now: it is based on a near-nadir incidence pointing, rotating fan-beam radar, used in a real-aperture mode. In this paper we present the CFOSAT mission, its objectives and main characteristics. We then focus on the SWIM instrument, the expected geophysical products and performances. Finally, we present ongoing studies based on existing satellite data of directional spectra of ocean waves (Sentinel-1, ..) and carried out in preparation to CAL/VAL activities and to future data exploitation.

  7. Effect of wind turbine generator model and siting on wind power changes out of large WECS arrays

    NASA Technical Reports Server (NTRS)

    Schleuter, R. A.; Park, G. L.; Lotfalian, M.; Dorsey, J.; Shayanfar, H.

    1981-01-01

    Methods of reducing the WECS generation change through selection of the wind turbine model for each site, selection of an appropriate siting configuration, and wind array controls are discussed. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented. Reduction of the wind generation change over ten minutes is shown to reduce the increase in spinning reserve, unloadable generation and load following requirements on unit commitment when significant WECS generation is present and the farm penetration constraint is satisfied. Controls on the blade pitch angle of all wind turbines in an array or a battery control are shown to reduce both the wind generation change out of an array and the effective farm penetration in anticipation of a storm so that the farm penetration constraint may be satisfied.

  8. Estimated changes in wind speed and wind power density over the western High Plains, 1971-2000

    NASA Astrophysics Data System (ADS)

    Greene, J. Scott; Chatelain, Matthew; Morrissey, Mark; Stadler, Steve

    2012-08-01

    This manuscript presents the results of research on the temporal patterns in wind speed and wind power density from 1971 to 2000. The study area is across the western High Plains states east of the Rocky Mountains in an area which has a proven wind power resource. Policies and economic analyses involving the rapidly expanding wind power industry have often assumed a constant in the wind resource; however, any temporal pattern or trend in wind speeds can have a meaningful impact on the reliability of wind power as an energy resource. Using data provided by the North American Regional Climate Change Assessment Program (NARCCAP) to analyze decadal and seasonal trends of wind data, this study shows that from 1971 to 2000 there were some notable changes in the NARCCAP simulated wind velocities over the study region. Wind speed trends across the central High Plains of the USA were most notable across the western portion of the study area along the higher terrain near the front range of the Rocky Mountains. The most significant changes occurred during winter and spring when a large portion of the study area experienced the most substantial decrease in wind speed, with a 20% reduction in wind power density during spring across the western portion of the study area. During summer and fall, the trends are less noticeable, with only very small changes in the summer. Fall was the only season that saw widespread increased values of wind power density from the 1970s to 1990s, with increases of nearly 10% in some southern areas of the study area. Based upon the analysis of the data and previous literature, it is theorized that these changes could be the result of changing synoptic patterns across the study region.

  9. Method for changing removable bearing for a wind turbine generator

    DOEpatents

    Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee , Gadre; Aniruddha Dattatraya

    2008-04-22

    A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

  10. Solar cycle changes in the polar solar wind

    NASA Technical Reports Server (NTRS)

    Coles, W. A.; Rickett, B. J.; Rumsey, V. H.; Kaufman, J. J.; Turley, D. G.; Ananthakrishnan, S.; Armstrong, J. W.; Harmons, J. K.; Scott, S. L.; Sime, D. G.

    1980-01-01

    It is noted that although the 11 year solar cycle was first recognized in 1843, it is still only poorly understood. Further, while there are satisfactory models for the magnetic variations, the underlying physics is still obscure. New observations on the changing three-dimensional form of the solar wind are presented which help relate some of the modulations observed in geomagnetic activity, the ionosphere, and the flux of galactic cosmic rays.

  11. Attraction of the cutaneous leishmaniasis vector Nyssomyia neivai (Diptera: Psychodidae) to host odour components in a wind tunnel

    PubMed Central

    2012-01-01

    Background Laboratory studies of host-seeking olfactory behaviour in sandflies have largely been restricted to the American visceral leishmaniasis vector Lutzomyia longipalpis. In comparison, almost nothing is known about the chemical ecology of related species, which transmit American cutaneous leishmaniasis (ACL), due in part to difficulties in raising these insects in the laboratory. Understanding how ACL vectors locate their hosts will be essential to developing new vector control strategies to combat this debilitating disease. Methods This study examined host-odour seeking behaviour of the ACL vector Nyssomyia neivai (Pinto) (=Lutzomyia neivai) using a wind tunnel olfactometer. The primary aim was to determine whether field-collected female N. neivai would respond to host odours in the laboratory, thereby eliminating the need to maintain colonies of these insects for behavioural experiments. Responses to two key host odour components, 1-octen-3-ol and lactic acid, and a commercially-available mosquito lure (BG-Lure™) were assessed and compared relative to an air control. We also tested whether trials could be conducted outside of the normal evening activity period of N. neivai without impacting on fly behaviour, and whether the same flies could be used to assess baseline responses to air without affecting responses to octenol, thereby reducing the number of flies required for experiments. Results Octenol was found to both activate host-seeking behaviour and attract female N. neivai in the wind tunnel, while lactic acid elicited weaker responses of activation and attractiveness under identical conditions. The BG-Lure did not activate or attract N. neivai under test conditions. Further experiments showed that sandfly behaviour in the wind tunnel was not affected by time of day, such that experiments need not be restricted to nocturnal hours. Moreover, using the same flies to measure both baseline responses to air and attraction to test compounds did not affect

  12. Evaluation of wind vectors measured by QuikSCAT using ocean buoy data along the Galician coast (NW Iberian Peninsula)

    NASA Astrophysics Data System (ADS)

    Alvarez, I.; Gomez-Gesteira, M.; deCastro, M.; Sousa, M. C.; Dias, J. M.; Santos, F.

    2012-04-01

    Wind above sea surface constitutes a key parameter to analyze coastal phenomena, like upwelling in the NW part of the Iberian Peninsula. The present work analyzes the accuracy of QuikSCAT for the period 2000-2009 by comparing satellite data with in situ data from three buoys placed along the NW coast of the Iberian Peninsula. The use of these long data series has two main objectives, on the one hand, the margin of error diminishes with the extent of the series and, on the other hand, it allows capturing the high inter-annual variability of the area. According to previous studies, the wet season is characterized by a high variability, in such a way that wind patterns change from year to year. The comparison confirms a low skill of QuikSCAT for low speed winds (<3 m/s) as previously pointed out by other authors. Once these winds were discarded, QuikSCAT revealed a higher accuracy for winds within the range 6-12 m/s. In direction, winds blowing from coast seem to be less accurately calculated by the satellite. Statistical results were similar for the three buoys in spite of the different coastal orientations. In average, the RMSE and bias for wind speed were 1.5 m/s and 0.2 m/s, respectively. Statistical data were also similar for wind direction, with the mean RMSE on the order of 34° and the mean bias on the order of 4° in absolute value. These statistical parameters are at least as accurate as those calculated in other near-shore areas all over the world. In particular, the bias was observed to be lower (in absolute value) than measured by most of the authors, which is possibly due to the high percentage of sampled winds lying within the interval [6-12] m/s, where satellite measurements are more accurate.

  13. A view from Minnesota: A changing climate for wind power

    SciTech Connect

    Noble, M.T.

    1997-12-31

    The author describes a program begun in Minnesota to address the problem of climate change and possible global warming. This projects aims at increasing understanding and appreciation of changes being seen in the US weather patterns and possible correlations with greenhouse gas emissions. Minnesota has taken a stance on mandating support for renewable power sources as a part of their electric utility mix. The author urges the business and industrial sectors of our economy to consider the impact on the US and its citizens of not supporting programs which are directed at reducing greenhouse gas emissions, including support for wind power projects.

  14. Polarimetric Ku-Band Scatterometer for High Accuracy, Large Swath Global Wind Vector Measurements

    NASA Technical Reports Server (NTRS)

    Tsai, Wu-Yang; Nghiem, Son V.; Huddleston, James; Spencer, Michael; Stiles, Bryan; West, Richard

    2000-01-01

    In the past, wind measurements from space using fan-beam antennas, such as Seasat Scatterometer (SASS-1), ERS-1 &2, and NASA scatterometer (NSCAT), required up to six large stick-like antennas and suffered a nadir gap of up to 400 km. In the near future, a spinning pencil-beam scatterometer system is to be used for the SeaWinds scatterometer on QuikSCAT (QSCAT) and on ADEOS-2 (SeaWinds). This scatterometer, though offering wind measurements in the nadir region, still suffers from degraded performance in the nadir and outer swath. The purpose of this paper is to present an advanced polarimetric spinning pencil-beam scatterometer system, which can significantly improve the wind performance across the entire swath. The polarimetric scatterometer simultaneously measures co-polarized backscatter and the polarimetric correlation of co- and cross-polarized radar returns from the ocean surface. The advantage over the conventional scatterometer system is that, while the co-polarization radar returns are even function of the wind direction, the polarimetric correlation is an odd function of wind direction due to the reflection symmetry of the wind roughened surface. Therefore, this polarimetric scatterometer system can provide additional, equivalent measurements at azimuth angle 45degree away from the corresponding co-polarization measurements. The combined co-polarization and correlation measurements enable good wind performance across the whole swath to be obtained. In this paper, we will first present the theoretical formulation of all of the key components required for designing a polarimetric scatterometer. Then, we show that good wind performance can be achieved by a slight improvement in the signal-to-noise ratio of the current QSCAT/SeaWinds design. We then present the predicated wind performance using computer simulation based on a model function for the co-polarized backscatter obtained from actual spaceborne scatterometer data and an estimated model function for

  15. Mapping of Malaria Vectors at District Level in India: Changing Scenario and Identified Gaps.

    PubMed

    Singh, Poonam; Lingala, Mercy Aparna L; Sarkar, Soma; Dhiman, Ramesh C

    2017-02-01

    Malaria is one of the six major vector-borne diseases in India, the endemicity of which changes with changes in ecological, climatic, and sociodevelopmental conditions. The anopheline vectors are greatly affected by ecological conditions such as deforestation, urbanization, climate and lifestyle. Despite the advent of tools such as Geographic Information System (GIS), the updated information on the distribution of anopheline vectors of malaria is not available. In India, the plan for vector control is organized at subcentral level but information about vectors is unavailable even at the district level. Therefore, a systematic presentation of vector distribution has been made to provide maps in respect of major vector species. A search of the literature for major vector species, that is, Anopheles culicifacies, Anopheles fluviatilis, Anopheles stephensi, Anopheles minimus, and Anopheles dirus sensu lato, since 1927 till 2015 was carried out. Data have been presented as present, absent, and no information about vector species during pre-eradication (1927-1958), posteradication (1959-1999), and current scenario (2000-2015). Vectors' distribution and malaria endemicity were mapped using Arc GIS. Of 630 districts of India, major vectors An. culicifacies, An. fluviatilis, and An. stephensi were present in 420, 241, and 243 districts, respectively. In 183 districts, there is no information on any major malaria vector species although 27 of them from the states of Arunachal Pradesh, Jharkhand, Manipur, and Mizoram are highly endemic for malaria, having incidences of 2-40 cases/1000/year. The identified gaps in vector distribution, particularly in malaria endemic areas, necessitate further surveys so as to generate the missing information.

  16. Effects of Local Anthropogenic Changes on Potential Malaria Vector Anopheles hyrcanus and West Nile Virus Vector Culex modestus, Camargue, France

    PubMed Central

    Ponçon, Nicolas; Balenghien, Thomas; Toty, Céline; Ferré, Jean Baptiste; Thomas, Cyrille; Dervieux, Alain; L’Ambert, Grégory; Schaffner, Francis; Bardin, Olivier

    2007-01-01

    Using historical data, we highlight the consequences of anthropogenic ecosystem modifications on the abundance of mosquitoes implicated as the current most important potential malaria vector, Anopheles hyrcanus, and the most important West Nile virus (WNV) vector, Culex modestus, in the Camargue region, France. From World War II to 1971, populations of these species increased as rice cultivation expanded in the region in a political context that supported agriculture. They then fell, likely because of decreased cultivation and increased pesticide use to control a rice pest. The species increased again after 2000 with the advent of more targeted pest-management strategies, mainly the results of European regulations decisions. An intertwined influence of political context, environmental constraints, technical improvements, and social factors led to changes in mosquito abundance that had potential consequences on malaria and WNV transmission. These findings suggest that anthropogenic changes should not be underestimated in vectorborne disease recrudescence. PMID:18258028

  17. A Long, Consistent Surface Wind Dataset for Climate Change Analysis: Application over the Equatorial Atlantic

    NASA Astrophysics Data System (ADS)

    Tokinaga, H.; Xie, S.

    2010-12-01

    Surface wind change is a principal factor for spatial patterns of sea surface temperature (SST) warming through changes in surface evaporation, ocean vertical mixing and wind-driven ocean circulation. However, historical ship-based measurements of sea surface wind speed displays a spurious upward trend due to increases in anemometer height. To correct this bias, we construct the Wave and Anemometer-based Sea-surface Wind (WASWind) dataset for the last six decades from ICOADS ship reports, applying height correction for anemometer measured winds, rejecting spurious Beaufort winds, and using wind wave height to estimate wind speed. WASWind substantially reduces the upward trend in wind speed and its trend patterns are quite similar to satellite-measured surface wind changes for the recent two decades. Surface wind changes in WASWind are consistent with historical sea level pressure observations over the global oceans, illustrating its utility for climate change analysis. As an example, WASWind captures relaxation of the equatorial trade winds coupled with a weakening of the equatorial Atlantic cold tongue over the last six decades. The surface wind changes are also consistent with those in atmospheric convection and subsurface temperature in this region, indicating that thermocline feedback plays a key role in recent climate change over the equatorial Atlantic.

  18. Host Life History Strategy, Species Diversity, and Habitat Influence Trypanosoma cruzi Vector Infection in Changing Landscapes

    PubMed Central

    Gottdenker, Nicole L.; Chaves, Luis Fernando; Calzada, José E.; Saldaña, Azael; Carroll, C. Ronald

    2012-01-01

    Background Anthropogenic land use may influence transmission of multi-host vector-borne pathogens by changing diversity, relative abundance, and community composition of reservoir hosts. These reservoir hosts may have varying competence for vector-borne pathogens depending on species-specific characteristics, such as life history strategy. The objective of this study is to evaluate how anthropogenic land use change influences blood meal species composition and the effects of changing blood meal species composition on the parasite infection rate of the Chagas disease vector Rhodnius pallescens in Panama. Methodology/Principal Findings R. pallescens vectors (N = 643) were collected in different habitat types across a gradient of anthropogenic disturbance. Blood meal species in DNA extracted from these vectors was identified in 243 (40.3%) vectors by amplification and sequencing of a vertebrate-specific fragment of the 12SrRNA gene, and T. cruzi vector infection was determined by pcr. Vector infection rate was significantly greater in deforested habitats as compared to contiguous forests. Forty-two different species of blood meal were identified in R. pallescens, and species composition of blood meals varied across habitat types. Mammals (88.3%) dominated R. pallescens blood meals. Xenarthrans (sloths and tamanduas) were the most frequently identified species in blood meals across all habitat types. A regression tree analysis indicated that blood meal species diversity, host life history strategy (measured as rmax, the maximum intrinsic rate of population increase), and habitat type (forest fragments and peridomiciliary sites) were important determinants of vector infection with T. cruzi. The mean intrinsic rate of increase and the skewness and variability of rmax were positively associated with higher vector infection rate at a site. Conclusions/Significance In this study, anthropogenic landscape disturbance increased vector infection with T. cruzi, potentially

  19. Combining Climatic Projections and Dispersal Ability: A Method for Estimating the Responses of Sandfly Vector Species to Climate Change

    PubMed Central

    Fischer, Dominik; Moeller, Philipp; Thomas, Stephanie M.; Naucke, Torsten J.; Beierkuhnlein, Carl

    2011-01-01

    Background In the Old World, sandfly species of the genus Phlebotomus are known vectors of Leishmania, Bartonella and several viruses. Recent sandfly catches and autochthonous cases of leishmaniasis hint on spreading tendencies of the vectors towards Central Europe. However, studies addressing potential future distribution of sandflies in the light of a changing European climate are missing. Methodology Here, we modelled bioclimatic envelopes using MaxEnt for five species with proven or assumed vector competence for Leishmania infantum, which are either predominantly located in (south-) western (Phlebotomus ariasi, P. mascittii and P. perniciosus) or south-eastern Europe (P. neglectus and P. perfiliewi). The determined bioclimatic envelopes were transferred to two climate change scenarios (A1B and B1) for Central Europe (Austria, Germany and Switzerland) using data of the regional climate model COSMO-CLM. We detected the most likely way of natural dispersal (“least-cost path”) for each species and hence determined the accessibility of potential future climatically suitable habitats by integrating landscape features, projected changes in climatic suitability and wind speed. Results and Relevance Results indicate that the Central European climate will become increasingly suitable especially for those vector species with a current south-western focus of distribution. In general, the highest suitability of Central Europe is projected for all species in the second half of the 21st century, except for P. perfiliewi. Nevertheless, we show that sandflies will hardly be able to occupy their climatically suitable habitats entirely, due to their limited natural dispersal ability. A northward spread of species with south-eastern focus of distribution may be constrained but not completely avoided by the Alps. Our results can be used to install specific monitoring systems to the projected risk zones of potential sandfly establishment. This is urgently needed for adaptation

  20. Characteristics of wind velocity and temperature change near an escarpment-shaped road embankment.

    PubMed

    Kim, Young-Moon; You, Ki-Pyo; You, Jang-Youl

    2014-01-01

    Artificial structures such as embankments built during the construction of highways influence the surrounding airflow. Various types of damage can occur due to changes in the wind velocity and temperature around highway embankments. However, no study has accurately measured micrometeorological changes (wind velocity and temperature) due to embankments. This study conducted a wind tunnel test and field measurement to identify changes in wind velocity and temperature before and after the construction of embankments around roads. Changes in wind velocity around an embankment after its construction were found to be influenced by the surrounding wind velocity, wind angle, and the level difference and distance from the embankment. When the level difference from the embankment was large and the distance was up to 3H, the degree of wind velocity declines was found to be large. In changes in reference wind velocities around the embankment, wind velocity increases were not proportional to the rate at which wind velocities declined. The construction of the embankment influenced surrounding temperatures. The degree of temperature change was large in locations with large level differences from the embankment at daybreak and during evening hours when wind velocity changes were small.

  1. State changes arising from wind transport in drylands (Invited)

    NASA Astrophysics Data System (ADS)

    Okin, G. S.; D'Odorico, P.

    2013-12-01

    The importance of soil transport due to wind has been increasingly understood as a crucial aspect of ecosystem evolution in drylands. Aeolian processes impact vegetation structure, topographic characteristics, and soil properties, and aeolian transport drives important feedbacks that give rise to multiple stable states. Here, we outline the results of several field and modeling experiments that show the critical interactions that occur amongst wind, vegetation, and soils. Measurements of transport, fallout radionuclide tracing, deposition, and vegetation growth shows clearly that aeolian transport can result in significant alteration of a variety of ecosystem and soil factors. Moreover, changes to vegetation and soils from land use, invasive species, and climate change impact aeolian transport. Both simplistic and sophisticated modeling approaches indicate that transport can produce multiple stable states in dryland ecosystems, and thus can participate in large-scale reorganization of soils and vegetation. These results also indicate that manipulation of aeolian transport might provide the opportunity to step some drylands back from critical thresholds and begin the process of recovery from unwanted ecosystem states.

  2. Impact to Space Shuttle Vehicle Trajectory on Day of Launch from change in Low Frequency Winds

    NASA Technical Reports Server (NTRS)

    Decker, Ryan K.; Puperi, Daniel; Leach, Richard

    2007-01-01

    The National Aeronautics and Space Administration's (NASA) Space Shuttle utilizes atmospheric winds on day of launch to develop throttle and steering commands to best optimize vehicle performance while keeping structural loading on the vehicle within limits. The steering commands and resultant trajectory are influenced by both the high and low frequency component of the wind. However, the low frequency component has a greater effect on the ascent design. Change in the low frequency wind content from the time of trajectory design until launch can induce excessive loading on the vehicle. Wind change limits have been derived to protect from launching in an environment where these temporal changes occur. Process of developing wind change limits are discussed followed by an observational study of temporal wind change in low frequency wind profiles at the NASA's Kennedy Space Center area are presented.

  3. Predicting malaria vector distribution under climate change scenarios in China: Challenges for malaria elimination.

    PubMed

    Ren, Zhoupeng; Wang, Duoquan; Ma, Aimin; Hwang, Jimee; Bennett, Adam; Sturrock, Hugh J W; Fan, Junfu; Zhang, Wenjie; Yang, Dian; Feng, Xinyu; Xia, Zhigui; Zhou, Xiao-Nong; Wang, Jinfeng

    2016-02-12

    Projecting the distribution of malaria vectors under climate change is essential for planning integrated vector control activities for sustaining elimination and preventing reintroduction of malaria. In China, however, little knowledge exists on the possible effects of climate change on malaria vectors. Here we assess the potential impact of climate change on four dominant malaria vectors (An. dirus, An. minimus, An. lesteri and An. sinensis) using species distribution models for two future decades: the 2030 s and the 2050 s. Simulation-based estimates suggest that the environmentally suitable area (ESA) for An. dirus and An. minimus would increase by an average of 49% and 16%, respectively, under all three scenarios for the 2030 s, but decrease by 11% and 16%, respectively in the 2050 s. By contrast, an increase of 36% and 11%, respectively, in ESA of An. lesteri and An. sinensis, was estimated under medium stabilizing (RCP4.5) and very heavy (RCP8.5) emission scenarios. in the 2050 s. In total, we predict a substantial net increase in the population exposed to the four dominant malaria vectors in the decades of the 2030 s and 2050 s, considering land use changes and urbanization simultaneously. Strategies to achieve and sustain malaria elimination in China will need to account for these potential changes in vector distributions and receptivity.

  4. Predicting malaria vector distribution under climate change scenarios in China: Challenges for malaria elimination

    NASA Astrophysics Data System (ADS)

    Ren, Zhoupeng; Wang, Duoquan; Ma, Aimin; Hwang, Jimee; Bennett, Adam; Sturrock, Hugh J. W.; Fan, Junfu; Zhang, Wenjie; Yang, Dian; Feng, Xinyu; Xia, Zhigui; Zhou, Xiao-Nong; Wang, Jinfeng

    2016-02-01

    Projecting the distribution of malaria vectors under climate change is essential for planning integrated vector control activities for sustaining elimination and preventing reintroduction of malaria. In China, however, little knowledge exists on the possible effects of climate change on malaria vectors. Here we assess the potential impact of climate change on four dominant malaria vectors (An. dirus, An. minimus, An. lesteri and An. sinensis) using species distribution models for two future decades: the 2030 s and the 2050 s. Simulation-based estimates suggest that the environmentally suitable area (ESA) for An. dirus and An. minimus would increase by an average of 49% and 16%, respectively, under all three scenarios for the 2030 s, but decrease by 11% and 16%, respectively in the 2050 s. By contrast, an increase of 36% and 11%, respectively, in ESA of An. lesteri and An. sinensis, was estimated under medium stabilizing (RCP4.5) and very heavy (RCP8.5) emission scenarios. in the 2050 s. In total, we predict a substantial net increase in the population exposed to the four dominant malaria vectors in the decades of the 2030 s and 2050 s, considering land use changes and urbanization simultaneously. Strategies to achieve and sustain malaria elimination in China will need to account for these potential changes in vector distributions and receptivity.

  5. Predicting malaria vector distribution under climate change scenarios in China: Challenges for malaria elimination

    PubMed Central

    Ren, Zhoupeng; Wang, Duoquan; Ma, Aimin; Hwang, Jimee; Bennett, Adam; Sturrock, Hugh J. W.; Fan, Junfu; Zhang, Wenjie; Yang, Dian; Feng, Xinyu; Xia, Zhigui; Zhou, Xiao-Nong; Wang, Jinfeng

    2016-01-01

    Projecting the distribution of malaria vectors under climate change is essential for planning integrated vector control activities for sustaining elimination and preventing reintroduction of malaria. In China, however, little knowledge exists on the possible effects of climate change on malaria vectors. Here we assess the potential impact of climate change on four dominant malaria vectors (An. dirus, An. minimus, An. lesteri and An. sinensis) using species distribution models for two future decades: the 2030 s and the 2050 s. Simulation-based estimates suggest that the environmentally suitable area (ESA) for An. dirus and An. minimus would increase by an average of 49% and 16%, respectively, under all three scenarios for the 2030 s, but decrease by 11% and 16%, respectively in the 2050 s. By contrast, an increase of 36% and 11%, respectively, in ESA of An. lesteri and An. sinensis, was estimated under medium stabilizing (RCP4.5) and very heavy (RCP8.5) emission scenarios. in the 2050 s. In total, we predict a substantial net increase in the population exposed to the four dominant malaria vectors in the decades of the 2030 s and 2050 s, considering land use changes and urbanization simultaneously. Strategies to achieve and sustain malaria elimination in China will need to account for these potential changes in vector distributions and receptivity. PMID:26868185

  6. Monte Carlo studies of ocean wind vector measurements by SCATT: Objective criteria and maximum likelihood estimates for removal of aliases, and effects of cell size on accuracy of vector winds

    NASA Technical Reports Server (NTRS)

    Pierson, W. J.

    1982-01-01

    The scatterometer on the National Oceanic Satellite System (NOSS) is studied by means of Monte Carlo techniques so as to determine the effect of two additional antennas for alias (or ambiguity) removal by means of an objective criteria technique and a normalized maximum likelihood estimator. Cells nominally 10 km by 10 km, 10 km by 50 km, and 50 km by 50 km are simulated for winds of 4, 8, 12 and 24 m/s and incidence angles of 29, 39, 47, and 53.5 deg for 15 deg changes in direction. The normalized maximum likelihood estimate (MLE) is correct a large part of the time, but the objective criterion technique is recommended as a reserve, and more quickly computed, procedure. Both methods for alias removal depend on the differences in the present model function at upwind and downwind. For 10 km by 10 km cells, it is found that the MLE method introduces a correlation between wind speed errors and aspect angle (wind direction) errors that can be as high as 0.8 or 0.9 and that the wind direction errors are unacceptably large, compared to those obtained for the SASS for similar assumptions.

  7. Chemical ecology of animal and human pathogen vectors in a changing global climate.

    PubMed

    Pickett, John A; Birkett, Michael A; Dewhirst, Sarah Y; Logan, James G; Omolo, Maurice O; Torto, Baldwyn; Pelletier, Julien; Syed, Zainulabeuddin; Leal, Walter S

    2010-01-01

    Infectious diseases affecting livestock and human health that involve vector-borne pathogens are a global problem, unrestricted by borders or boundaries, which may be exacerbated by changing global climate. Thus, the availability of effective tools for control of pathogen vectors is of the utmost importance. The aim of this article is to review, selectively, current knowledge of the chemical ecology of pathogen vectors that affect livestock and human health in the developed and developing world, based on key note lectures presented in a symposium on "The Chemical Ecology of Disease Vectors" at the 25th Annual ISCE meeting in Neuchatel, Switzerland. The focus is on the deployment of semiochemicals for monitoring and control strategies, and discusses briefly future directions that such research should proceed along, bearing in mind the environmental challenges associated with climate change that we will face during the 21st century.

  8. Modeling and space vector control of a novel multilevel matrix converter for variable-speed wind power generators

    NASA Astrophysics Data System (ADS)

    Al-Naseem, Osama Abdulrahman

    A novel multilevel matrix converter is developed to efficiently transfer energy between a three-phase variable-speed generator of a wind turbine and a three-phase ac utility network. Optimizing the energy transfer efficiency at light load is critical in variable-speed wind generators. Laboratory experiment suggests that converter efficiency at light load may be increased via soft-switching and multilevel switching techniques. The new converter includes the advantages of multilevel converters, such as reduced harmonic content, increased power handling capability without additional switching loss, and high efficiency at low machine voltages. It also features the characteristics of conventional matrix converters, such as space vector control and improved efficiency via auxiliary resonant commutation soft-switching techniques. Similar to a conventional matrix converter, the novel multilevel matrix converter uses a nine-switch matrix with four-quadrant switches to connect input phases at one side of the converter with output phases at the other side of the converter. However, the switches of the new converter are configured differently from those used in the conventional matrix converter. Each switch of the new converter is a cell that resembles a full-bridge inverter topology and can assume three voltage levels while used. Semiconductor devices in a switch cell are always clamped to a known constant do voltage of a capacitor. This is a typical characteristic of multilevel converters where device voltage stresses are reduced by clamping the main transistor voltages to low levels. With reduced voltage stresses, switching frequency can be increased to allow for reduced size of filter magnetics. Unlike conventional matrix converter, the multilevel matrix converter uses inductors on both input and output sides of the converter. This symmetry allows for both step up and step down operations. Each switch cell features double the power handling capability compared to the four

  9. Evaluation of the impacts of climate change on disease vectors through ecological niche modelling.

    PubMed

    Carvalho, B M; Rangel, E F; Vale, M M

    2016-12-15

    Vector-borne diseases are exceptionally sensitive to climate change. Predicting vector occurrence in specific regions is a challenge that disease control programs must meet in order to plan and execute control interventions and climate change adaptation measures. Recently, an increasing number of scientific articles have applied ecological niche modelling (ENM) to study medically important insects and ticks. With a myriad of available methods, it is challenging to interpret their results. Here we review the future projections of disease vectors produced by ENM, and assess their trends and limitations. Tropical regions are currently occupied by many vector species; but future projections indicate poleward expansions of suitable climates for their occurrence and, therefore, entomological surveillance must be continuously done in areas projected to become suitable. The most commonly applied methods were the maximum entropy algorithm, generalized linear models, the genetic algorithm for rule set prediction, and discriminant analysis. Lack of consideration of the full-known current distribution of the target species on models with future projections has led to questionable predictions. We conclude that there is no ideal 'gold standard' method to model vector distributions; researchers are encouraged to test different methods for the same data. Such practice is becoming common in the field of ENM, but still lags behind in studies of disease vectors.

  10. The Learning Process and Technological Change in Wind Power: Evidence from China's CDM Wind Projects

    ERIC Educational Resources Information Center

    Tang, Tian; Popp, David

    2016-01-01

    The Clean Development Mechanism (CDM) is a project-based carbon trade mechanism that subsidizes the users of climate-friendly technologies and encourages technology transfer. The CDM has provided financial support for a large share of Chinese wind projects since 2002. Using pooled cross-sectional data of 486 registered CDM wind projects in China…

  11. Using state-and-transition models to evaluate impacts of land cover change on wind erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion of rangeland soils is a global problem exacerbated by land cover change. Despite efforts to quantify the impacts of land cover change on wind erosion, assessment uncertainty remains large. We address this uncertainty by evaluating the application of ecological sites and state-and-transi...

  12. Projected changes in the annual wind-wave cycle

    NASA Astrophysics Data System (ADS)

    Stopa, Justin; Hemer, Mark

    2016-04-01

    The uneven distribution of the sun's energy directly and indirectly drives physical atmosphere and ocean processes. This creates intricate spatial patterns within the seasonal cycle where higher order harmonics are seen to play an important role in regional climates. The annual cycle and associated harmonics are the strongest oscillations within the climate system and describe the majority of variance across the oceans. Consequently when studying climate oscillations, it is common practice to remove the seasonal cycle in order to elucidate inter-annual cycles. Furthermore the annual cycle plays an important role in the evolution of other inter-annual oscillations through non-linear coupling (e.g ENSO). Despite the important role of the seasons within the climate system very few studies describe the seasonality with any rigor. Therefore our focus is to describe the higher harmonics linked to the annual cycle and how they are expected to evolve in a changing climate. Using simulations from the Coordinated Ocean Wave Climate Project, the seasonality of multiple mid and end of the 21st century wind-wave climate projections are analyzed relative to historical experiment forced simulations. A comparison of various GCM forced wave simulations to reanalysis datasets reveals that a multi-model ensemble best describes the seasons. This ensemble is used to describe the changes within the wave seasonality. A systematic analysis reveals the primary mode of the seasons is relatively unchanged in the mid and end century. The largest changes occur in the second and third modes. The second mode defines the shift or translation within the seasons while the third mode characterizes relative change between the seasonal extremes (ie sharpening or flattening of the waveform). The relative changes in the second and third modes are not homogeneous and intricate patterns are revealed. Certain regions have sharper contrast in seasonality while other regions have a longer strong season. In

  13. Pressure distribution on a vectored-thrust V/STOL fighter in the transition-speed range. [wind tunnel tests to measure pressure distribution on body and wing

    NASA Technical Reports Server (NTRS)

    Mineck, R. E.; Margason, R. J.

    1974-01-01

    A wind-tunnel investigation has been conducted in the Langley V/STOL tunnel with a vectored-thrust V/STOL fighter configuration to obtain detailed pressure measurements on the body and on the wing in the transition-speed range. The vectored-thrust jet exhaust induced a region of negative pressure coefficients on the lower surface of the wing and on the bottom of the fuselage. The location of the jet exhaust relative to the wing was a major factor in determining the extent of the region of negative pressure coefficients.

  14. Climate Change and Vector Borne Diseases on NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Cole, Stuart K.; DeYoung, Russell J.; Shepanek, Marc A.; Kamel, Ahmed

    2014-01-01

    Increasing global temperature, weather patterns with above average storm intensities, and higher sea levels have been identified as phenomena associated with global climate change. As a causal system, climate change could contribute to vector borne diseases in humans. Vectors of concern originate from the vicinity of Langley Research Center include mosquitos and ticks that transmit disease that originate regionally, nationwide, or from outside the US. Recognizing changing conditions, vector borne diseases propagate under climate change conditions, and understanding the conditions in which they may exist or propagate, presents opportunities for monitoring their progress and mitigating their potential impacts through communication, continued monitoring, and adaptation. Personnel comprise a direct and fundamental support to NASA mission success, continuous and improved understanding of climatic conditions, and the resulting consequence of disease from these conditions, helps to reduce risk in terrestrial space technologies, ground operations, and space research. This research addresses conditions which are attributed to climatic conditions which promote environmental conditions conducive to the increase of disease vectors. This investigation includes evaluation of local mosquito population count and rainfall data for statistical correlation and identification of planning recommendations unique to LaRC, other NASA Centers to assess adaptation approaches, Center-level planning strategies.

  15. The impact of climate change on the U.S. wind energy resource

    SciTech Connect

    Daniel Kirk-Davidoff; Daniel Barrie

    2013-03-19

    The growing need for low-carbon emitting electricity sources has resulted in rapid growth in the wind power industry. The size and steadiness of the offshore wind resource has attracted growing investment in the planning of offshore wind turbine installations. Decisions about the location and character of wind farms should be made with an eye not only to present but also future wind resource, which may change as increasing carbon dioxide forces reductions in the poleward temperature gradient, and thus potentially in the mean tropospheric westerly winds. I propose to use the new North American Regional Climate Change Assessment Program climate projections to estimate the change of the wind power resource under various carbon dioxide loading scenarios and for a range of climate models. We will compare our assessment with both our assessment based on the IPCC AR4 model runs, to explore the extent to which improved model resolution changes the prediction for the wind power resource, and with present day estimates from reanalysis and scatterometer winds.

  16. Wind shear measuring on board an airliner

    NASA Technical Reports Server (NTRS)

    Krauspe, P.

    1984-01-01

    A measurement technique which continuously determines the wind vector on board an airliner during takeoff and landing is introduced. Its implementation is intended to deliver sufficient statistical background concerning low frequency wind changes in the atmospheric boundary layer and extended knowledge about deterministic wind shear modeling. The wind measurement scheme is described and the adaptation of apparatus onboard an A300 airbus is shown. Preliminary measurements made during level flight demonstrate the validity of the method.

  17. Assessment of changes of vector borne diseases with wetland characteristics using multivariate analysis.

    PubMed

    Sheela, A M; Sarun, S; Justus, J; Vineetha, P; Sheeja, R V

    2015-04-01

    Vector borne diseases are a threat to human health. Little attention has been paid to the prevention of these diseases. We attempted to identify the significant wetland characteristics associated with the spread of chikungunya, dengue fever and malaria in Kerala, a tropical region of South West India using multivariate analyses (hierarchical cluster analysis, factor analysis and multiple regression). High/medium turbid coastal lagoons and inland water-logged wetlands with aquatic vegetation have significant effect on the incidence of chikungunya while dengue influenced by high turbid coastal beaches and malaria by medium turbid coastal beaches. The high turbidity in water is due to the urban waste discharge namely sewage, sullage and garbage from the densely populated cities and towns. The large extent of wetland is low land area favours the occurrence of vector borne diseases. Hence the provision of pollution control measures at source including soil erosion control measures is vital. The identification of vulnerable zones favouring the vector borne diseases will help the authorities to control pollution especially from urban areas and prevent these vector borne diseases. Future research should cover land use cover changes, climatic factors, seasonal variations in weather and pollution factors favouring the occurrence of vector borne diseases.

  18. North Sea wind climate in changing weather regimes

    NASA Astrophysics Data System (ADS)

    Anders, Ivonne; Rockel, Burkhardt

    2015-04-01

    Results from regional climate models (RCMs) are getting more and more important in future wind climate assessment. From RCMs often only the daily wind speed is available, but no information on prevailing wind direction of each day. Weather regime classification can close this gap and models ability of simulating surface wind speed can be analysed in detail. Several objective regime classifications have been investigated to be a sufficient diagnostic tool to evaluate the present wind climate at the German and Dutch coastal area of the North Sea. The classification by Jenkinson and Collison (1977) uses values for mean sea level pressure at 16 locations centered over the North Sea. Beside the predefined 8 prevailed wind directions and the two possibilities on cyclonic or anticyclonic turbulence, 2x8 hybrid weather types can be defined. In this way 27 different regimes can be distinguished including a class of non-classifiable cases. The 27 regimes could be reduced to a number of 11 by allotting the hybrid types to the directional or the centered types. As the classification is carried out for the North Sea based on ERA40 mean sea level pressure the different regimes clearly reflect the mean wind characteristics at the stations. Comparing the wind roses for the individual observations leads to the assumption that the regime classification described before fits the requirements to carry out the regime dependent evaluation of the RCMs with a focus on the German and Dutch coast. Trends in the occurrence of the regimes in the winter period of 1961 to 2000 show an increase of the regimes with Western and Southwestern wind directions and a decrease of wind events from Eastern directions in the North Sea. The trend is dominated by the strong positive phase of the NAO especially in the months January to March starting in the beginning of the 1980s. Due to the applied method ERA40 and the RCMs do not necessarily show the same regime at each day. The agreement among the RCM

  19. Recent tax law changes create new opportunities for leasing wind energy property

    SciTech Connect

    Schutzer, George J.

    2010-01-15

    Recent changes in tax law make leveraged lease transactions far more attractive on paper than they were before the changes. However, changes in the economy and the financial industry and other changes in law counterbalance the favorable tax law changes and make it uncertain whether lease transactions will be used to finance new wind facilities. (author)

  20. Operation of a Wind Turbine-Flywheel Energy Storage System under Conditions of Stochastic Change of Wind Energy

    PubMed Central

    2014-01-01

    The paper presents the issues of a wind turbine-flywheel energy storage system (WT-FESS) operation under real conditions. Stochastic changes of wind energy in time cause significant fluctuations of the system output power and as a result have a negative impact on the quality of the generated electrical energy. In the author's opinion it is possible to reduce the aforementioned effects by using an energy storage of an appropriate type and capacity. It was assumed that based on the technical parameters of a wind turbine-energy storage system and its geographical location one can determine the boundary capacity of the storage, which helps prevent power cuts to the grid at the assumed probability. Flywheel energy storage was selected due to its characteristics and technical parameters. The storage capacity was determined based on an empirical relationship using the results of the proposed statistical and energetic analysis of the measured wind velocity courses. A detailed algorithm of the WT-FESS with the power grid system was developed, eliminating short-term breaks in the turbine operation and periods when the wind turbine power was below the assumed level. PMID:25215326

  1. Operation of a wind turbine-flywheel energy storage system under conditions of stochastic change of wind energy.

    PubMed

    Tomczewski, Andrzej

    2014-01-01

    The paper presents the issues of a wind turbine-flywheel energy storage system (WT-FESS) operation under real conditions. Stochastic changes of wind energy in time cause significant fluctuations of the system output power and as a result have a negative impact on the quality of the generated electrical energy. In the author's opinion it is possible to reduce the aforementioned effects by using an energy storage of an appropriate type and capacity. It was assumed that based on the technical parameters of a wind turbine-energy storage system and its geographical location one can determine the boundary capacity of the storage, which helps prevent power cuts to the grid at the assumed probability. Flywheel energy storage was selected due to its characteristics and technical parameters. The storage capacity was determined based on an empirical relationship using the results of the proposed statistical and energetic analysis of the measured wind velocity courses. A detailed algorithm of the WT-FESS with the power grid system was developed, eliminating short-term breaks in the turbine operation and periods when the wind turbine power was below the assumed level.

  2. Evidence that implicit assumptions of 'no evolution' of disease vectors in changing environments can be violated on a rapid timescale.

    PubMed

    Egizi, Andrea; Fefferman, Nina H; Fonseca, Dina M

    2015-04-05

    Projected impacts of climate change on vector-borne disease dynamics must consider many variables relevant to hosts, vectors and pathogens, including how altered environmental characteristics might affect the spatial distributions of vector species. However, many predictive models for vector distributions consider their habitat requirements to be fixed over relevant time-scales, when they may actually be capable of rapid evolutionary change and even adaptation. We examine the genetic signature of a spatial expansion by an invasive vector into locations with novel temperature conditions compared to its native range as a proxy for how existing vector populations may respond to temporally changing habitat. Specifically, we compare invasions into different climate ranges and characterize the importance of selection from the invaded habitat. We demonstrate that vector species can exhibit evolutionary responses (altered allelic frequencies) to a temperature gradient in as little as 7-10 years even in the presence of high gene flow, and further, that this response varies depending on the strength of selection. We interpret these findings in the context of climate change predictions for vector populations and emphasize the importance of incorporating vector evolution into models of future vector-borne disease dynamics.

  3. Simulation comparison of a decoupled longitudinal control system and a velocity vector control wheel steering system during landings in wind shear

    NASA Technical Reports Server (NTRS)

    Kimball, G., Jr.

    1980-01-01

    A simulator comparison of the velocity vector control wheel steering (VCWS) system and a decoupled longitudinal control system is presented. The piloting task was to use the electronic attitude direction indicator (EADI) to capture and maintain a 3 degree glide slope in the presence of wind shear and to complete the landing using the perspective runway included on the EADI. The decoupled control system used constant prefilter and feedback gains to provide steady state decoupling of flight path angle, pitch angle, and forward velocity. The decoupled control system improved the pilots' ability to control airspeed and flight path angle during the final stages of an approach made in severe wind shear. The system also improved their ability to complete safe landings. The pilots preferred the decoupled control system in severe winds and, on a pilot rating scale, rated the approach and landing task with the decoupled control system as much as 3 to 4 increments better than use of the VCWS system.

  4. Constraining flavor changing interactions from LHC Run-2 dilepton bounds with vector mediators

    NASA Astrophysics Data System (ADS)

    Queiroz, Farinaldo S.; Siqueira, Clarissa; Valle, José W. F.

    2016-12-01

    Within the context of vector mediators, is a new signal observed in flavor changing interactions, particularly in the neutral mesons systems K0 -Kbar0, D0 -Dbar0 and B0 -B0 bar , consistent with dilepton resonance searches at the LHC? In the attempt to address this very simple question, we discuss the complementarity between flavor changing neutral current (FCNC) and dilepton resonance searches at the LHC run 2 at 13 TeV with 3.2 fb-1 of integrated luminosity, in the context of vector mediators at tree level. Vector mediators, are often studied in the flavor changing framework, specially in the light of the recent LHCb anomaly observed at the rare B decay. However, the existence of stringent dilepton bound severely constrains flavor changing interactions, due to restrictive limits on the Z‧ mass. We discuss this interplay explicitly in the well motivated framework of a 3-3-1 scheme, where fermions and scalars are arranged in the fundamental representation of the weak SU(3) gauge group. Due to the paucity of relevant parameters, we conclude that dilepton data leave little room for a possible new physics signal stemming from these systems, unless a very peculiar texture parametrization is used in the diagonalization of the CKM matrix. In other words, if a signal is observed in such flavor changing interactions, it unlikely comes from a 3-3-1 model.

  5. Climate Change and Aedes Vectors: 21st Century Projections for Dengue Transmission in Europe.

    PubMed

    Liu-Helmersson, Jing; Quam, Mikkel; Wilder-Smith, Annelies; Stenlund, Hans; Ebi, Kristie; Massad, Eduardo; Rocklöv, Joacim

    2016-05-01

    Warming temperatures may increase the geographic spread of vector-borne diseases into temperate areas. Although a tropical mosquito-borne viral disease, a dengue outbreak occurred in Madeira, Portugal, in 2012; the first in Europe since 1920s. This outbreak emphasizes the potential for dengue re-emergence in Europe given changing climates. We present estimates of dengue epidemic potential using vectorial capacity (VC) based on historic and projected temperature (1901-2099). VC indicates the vectors' ability to spread disease among humans. We calculated temperature-dependent VC for Europe, highlighting 10 European cities and three non-European reference cities. Compared with the tropics, Europe shows pronounced seasonality and geographical heterogeneity. Although low, VC during summer is currently sufficient for dengue outbreaks in Southern Europe to commence-if sufficient vector populations (either Ae. aegypti and Ae. albopictus) were active and virus were introduced. Under various climate change scenarios, the seasonal peak and time window for dengue epidemic potential increases during the 21st century. Our study maps dengue epidemic potential in Europe and identifies seasonal time windows when major cities are most conducive for dengue transmission from 1901 to 2099. Our findings illustrate, that besides vector control, mitigating greenhouse gas emissions crucially reduces the future epidemic potential of dengue in Europe.

  6. Projecting Wind Energy Potential Under Climate Change with Ensemble of Climate Model Simulations

    NASA Astrophysics Data System (ADS)

    Jain, A.; Shashikanth, K.; Ghosh, S.; Mukherjee, P. P.

    2013-12-01

    Recent years have witnessed an increasing global concern over energy sustainability and security, triggered by a number of issues, such as (though not limited to): fossil fuel depletion, energy resource geopolitics, economic efficiency versus population growth debate, environmental concerns and climate change. Wind energy is a renewable and sustainable form of energy in which wind turbines convert the kinetic energy of wind into electrical energy. Global warming and differential surface heating may significantly impact the wind velocity and hence the wind energy potential. Sustainable design of wind mills requires understanding the impacts of climate change on wind energy potential, which we evaluate here with multiple General Circulation Models (GCMs). GCMs simulate the climate variables globally considering the greenhouse emission scenarios provided as Representation Concentration path ways (RCPs). Here we use new generation climate model outputs obtained from Coupled model Intercomparison Project 5(CMIP5). We first compute the wind energy potential with reanalysis data (NCEP/ NCAR), at a spatial resolution of 2.50, where the gridded data is fitted to Weibull distribution and with the Weibull parameters, the wind energy densities are computed at different grids. The same methodology is then used, to CMIP5 outputs (resultant of U-wind and V-wind) of MRI, CMCC, BCC, CanESM, and INMCM4 for historical runs. This is performed separately for four seasons globally, MAM, JJA, SON and DJF. We observe the muti-model average of wind energy density for historic period has significant bias with respect to that of reanalysis product. Here we develop a quantile based superensemble approach where GCM quantiles corresponding to selected CDF values are regressed to reanalysis data. It is observed that this regression approach takes care of both, bias in GCMs and combination of GCMs. With superensemble, we observe that the historical wind energy density resembles quite well with

  7. Sensitivity of Southern Ocean overturning to wind stress changes: Role of surface restoring time scales

    NASA Astrophysics Data System (ADS)

    Zhai, Xiaoming; Munday, David R.

    2014-12-01

    The influence of different surface restoring time scales on the response of the Southern Ocean overturning circulation to wind stress changes is investigated using an idealised channel model. Regardless of the restoring time scales chosen, the eddy-induced meridional overturning circulation (MOC) is found to compensate for changes of the direct wind-driven Eulerian-mean MOC, rendering the residual MOC less sensitive to wind stress changes. However, the extent of this compensation depends strongly on the restoring time scale: residual MOC sensitivity increases with decreasing restoring time scale. Strong surface restoring is shown to limit the ability of the eddy-induced MOC to change in response to wind stress changes and as such suppresses the eddy compensation effect. These model results are consistent with qualitative arguments derived from residual-mean theory and may have important implications for interpreting past and future observations.

  8. 20% Wind Energy - Diversifying Our Energy Portfolio and Addressing Climate Change (Brochure)

    SciTech Connect

    Not Available

    2008-05-01

    This brochure describes the R&D efforts needed for wind energy to meet 20% of the U.S. electrical demand by 2030. In May 2008, DOE published its report, 20% Wind Energy by 2030, which presents an in-depth analysis of the potential for wind energy in the United States and outlines a potential scenario to boost wind electric generation from its current production of 16.8 gigawatts (GW) to 304 GW by 2030. According to the report, achieving 20% wind energy by 2030 could help address climate change by reducing electric sector carbon dioxide (CO2) emissions by 825 million metric tons (20% of the electric utility sector CO2 emissions if no new wind is installed by 2030), and it will enhance our nation's energy security by diversifying our electricity portfolio as wind energy is an indigenous energy source with stable prices not subject to fuel volatility. According to the report, increasing our nation's wind generation could also boost local rural economies and contribute to significant growth in manufacturing and the industry supply chain. Rural economies will benefit from a substantial increase in land use payments, tax benefits and the number of well-paying jobs created by the wind energy manufacturing, construction, and maintenance industries. Although the initial capital costs of implementing the 20% wind scenario would be higher than other generation sources, according to the report, wind energy offers lower ongoing energy costs than conventional generation power plants for operations, maintenance, and fuel. The 20% scenario could require an incremental investment of as little as $43 billion (net present value) more than a base-case no new wind scenario. This would represent less than 0.06 cent (6 one-hundredths of 1 cent) per kilowatt-hour of total generation by 2030, or roughly 50 cents per month per household. The report concludes that while achieving the 20% wind scenario is technically achievable, it will require enhanced transmission infrastructure

  9. Projected Future Distributions of Vectors of Trypanosoma cruzi in North America under Climate Change Scenarios

    PubMed Central

    Garza, Miroslava; Feria Arroyo, Teresa Patricia; Casillas, Edgar A.; Sanchez-Cordero, Victor; Rivaldi, Chissa-Louise; Sarkar, Sahotra

    2014-01-01

    Background Chagas disease kills approximately 45 thousand people annually and affects 10 million people in Latin America and the southern United States. The parasite that causes the disease, Trypanosoma cruzi, can be transmitted by insects of the family Reduviidae, subfamily Triatominae. Any study that attempts to evaluate risk for Chagas disease must focus on the ecology and biogeography of these vectors. Expected distributional shifts of vector species due to climate change are likely to alter spatial patterns of risk of Chagas disease, presumably through northward expansion of high risk areas in North America. Methodology/Principal Findings We forecast the future (2050) distributions in North America of Triatoma gerstaeckeri and T. sanguisuga, two of the most common triatomine species and important vectors of Trypanosoma cruzi in the southern United States. Our aim was to analyze how climate change might affect the future shift of Chagas disease in North America using a maximum entropy algorithm to predict changes in suitable habitat based on vector occurrence points and predictive environmental variables. Projections based on three different general circulation models (CCCMA, CSIRO, and HADCM3) and two IPCC scenarios (A2 and B2) were analyzed. Twenty models were developed for each case and evaluated via cross-validation. The final model averages result from all twenty of these models. All models had AUC >0.90, which indicates that the models are robust. Our results predict a potential northern shift in the distribution of T. gerstaeckeri and a northern and southern distributional shift of T. sanguisuga from its current range due to climate change. Conclusions/Significance The results of this study provide baseline information for monitoring the northward shift of potential risk from Chagas disease in the face of climate change. PMID:24831117

  10. Effects of El Niño-driven changes in wind patterns on North Pacific albatrosses.

    PubMed

    Thorne, L H; Conners, M G; Hazen, E L; Bograd, S J; Antolos, M; Costa, D P; Shaffer, S A

    2016-06-01

    Changes to patterns of wind and ocean currents are tightly linked to climate change and have important implications for cost of travel and energy budgets in marine vertebrates. We evaluated how El Niño-Southern Oscillation (ENSO)-driven wind patterns affected breeding Laysan and black-footed albatross across a decade of study. Owing to latitudinal variation in wind patterns, wind speed differed between habitat used during incubation and brooding; during La Niña conditions, wind speeds were lower in incubating Laysan (though not black-footed) albatross habitat, but higher in habitats used by brooding albatrosses. Incubating Laysan albatrosses benefited from increased wind speeds during El Niño conditions, showing increased travel speeds and mass gained during foraging trips. However, brooding albatrosses did not benefit from stronger winds during La Niña conditions, instead experiencing stronger cumulative headwinds and a smaller proportion of trips in tailwinds. Increased travel costs during brooding may contribute to the lower reproductive success observed in La Niña conditions. Furthermore, benefits of stronger winds in incubating habitat may explain the higher reproductive success of Laysan albatross during El Niño conditions. Our findings highlight the importance of considering habitat accessibility and cost of travel when evaluating the impacts of climate-driven habitat change on marine predators.

  11. Regional and seasonal response of a West Nile virus vector to climate change

    PubMed Central

    Morin, Cory W.; Comrie, Andrew C.

    2013-01-01

    Climate change will affect the abundance and seasonality of West Nile virus (WNV) vectors, altering the risk of virus transmission to humans. Using downscaled general circulation model output, we calculate a WNV vector's response to climate change across the southern United States using process-based modeling. In the eastern United States, Culex quinquefasciatus response to projected climate change displays a latitudinal and elevational gradient. Projected summer population depressions as a result of increased immature mortality and habitat drying are most severe in the south and almost absent further north; extended spring and fall survival is ubiquitous. Much of California also exhibits a bimodal pattern. Projected onset of mosquito season is delayed in the southwestern United States because of extremely dry and hot spring and summers; however, increased temperature and late summer and fall rains extend the mosquito season. These results are unique in being a broad-scale calculation of the projected impacts of climate change on a WNV vector. The results show that, despite projected widespread future warming, the future seasonal response of C. quinquefasciatus populations across the southern United States will not be homogeneous, and will depend on specific combinations of local and regional conditions. PMID:24019459

  12. Regional and seasonal response of a West Nile virus vector to climate change.

    PubMed

    Morin, Cory W; Comrie, Andrew C

    2013-09-24

    Climate change will affect the abundance and seasonality of West Nile virus (WNV) vectors, altering the risk of virus transmission to humans. Using downscaled general circulation model output, we calculate a WNV vector's response to climate change across the southern United States using process-based modeling. In the eastern United States, Culex quinquefasciatus response to projected climate change displays a latitudinal and elevational gradient. Projected summer population depressions as a result of increased immature mortality and habitat drying are most severe in the south and almost absent further north; extended spring and fall survival is ubiquitous. Much of California also exhibits a bimodal pattern. Projected onset of mosquito season is delayed in the southwestern United States because of extremely dry and hot spring and summers; however, increased temperature and late summer and fall rains extend the mosquito season. These results are unique in being a broad-scale calculation of the projected impacts of climate change on a WNV vector. The results show that, despite projected widespread future warming, the future seasonal response of C. quinquefasciatus populations across the southern United States will not be homogeneous, and will depend on specific combinations of local and regional conditions.

  13. Eclipse-induced wind changes over the British Isles on the 20 March 2015

    PubMed Central

    2016-01-01

    The British Isles benefits from dense meteorological observation networks, enabling insights into the still-unresolved effects of solar eclipse events on the near-surface wind field. The near-surface effects of the solar eclipse of 20 March 2015 are derived through comparison of output from the Met Office’s operational weather forecast model (which is ignorant of the eclipse) with data from two meteorological networks: the Met Office’s land surface station (MIDAS) network and a roadside measurement network operated by Vaisala. Synoptic-evolution relative calculations reveal the cooling and increase in relative humidity almost universally attributed to eclipse events. In addition, a slackening of wind speeds by up to about 2 knots in already weak winds and backing in wind direction of about 20° under clear skies across middle England are attributed to the eclipse event. The slackening of wind speed is consistent with the previously reported boundary layer stabilization during eclipse events. Wind direction changes have previously been attributed to a large-scale ‘eclipse-induced cold-cored cyclone’, mountain slope flows, and changes in the strength of sea breezes. A new explanation is proposed here by analogy with nocturnal wind changes at sunset and shown to predict direction changes consistent with those observed. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550759

  14. Eclipse-induced wind changes over the British Isles on the 20 March 2015.

    PubMed

    Gray, S L; Harrison, R G

    2016-09-28

    The British Isles benefits from dense meteorological observation networks, enabling insights into the still-unresolved effects of solar eclipse events on the near-surface wind field. The near-surface effects of the solar eclipse of 20 March 2015 are derived through comparison of output from the Met Office's operational weather forecast model (which is ignorant of the eclipse) with data from two meteorological networks: the Met Office's land surface station (MIDAS) network and a roadside measurement network operated by Vaisala. Synoptic-evolution relative calculations reveal the cooling and increase in relative humidity almost universally attributed to eclipse events. In addition, a slackening of wind speeds by up to about 2 knots in already weak winds and backing in wind direction of about 20° under clear skies across middle England are attributed to the eclipse event. The slackening of wind speed is consistent with the previously reported boundary layer stabilization during eclipse events. Wind direction changes have previously been attributed to a large-scale 'eclipse-induced cold-cored cyclone', mountain slope flows, and changes in the strength of sea breezes. A new explanation is proposed here by analogy with nocturnal wind changes at sunset and shown to predict direction changes consistent with those observed.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.

  15. Projection of Climate Change Influences on U.S. West Nile Virus Vectors

    PubMed Central

    Brown, Heidi E.; Young, Alex; Lega, Joceline; Andreadis, Theodore G.; Schurich, Jessica; Comrie, Andrew

    2015-01-01

    While estimates of the impact of climate change on health are necessary for health care planners and climate change policy makers, models to produce quantitative estimates remain scarce. We describe a freely available dynamic simulation model parameterized for three West Nile virus vectors, which provides an effective tool for studying vector-borne disease risk due to climate change. The Dynamic Mosquito Simulation Model is parameterized with species specific temperature-dependent development and mortality rates. Using downscaled daily weather data, we estimate mosquito population dynamics under current and projected future climate scenarios for multiple locations across the country. Trends in mosquito abundance were variable by location, however, an extension of the vector activity periods, and by extension disease risk, was almost uniformly observed. Importantly, mid-summer decreases in abundance may be off-set by shorter extrinsic incubation periods resulting in a greater proportion of infective mosquitoes. Quantitative descriptions of the effect of temperature on the virus and mosquito are critical to developing models of future disease risk. PMID:27057131

  16. Projection of Climate Change Influences on U.S. West Nile Virus Vectors.

    PubMed

    Brown, Heidi E; Young, Alex; Lega, Joceline; Andreadis, Theodore G; Schurich, Jessica; Comrie, Andrew

    2015-12-01

    While estimates of the impact of climate change on health are necessary for health care planners and climate change policy makers, models to produce quantitative estimates remain scarce. We describe a freely available dynamic simulation model parameterized for three West Nile virus vectors, which provides an effective tool for studying vector-borne disease risk due to climate change. The Dynamic Mosquito Simulation Model is parameterized with species specific temperature-dependent development and mortality rates. Using downscaled daily weather data, we estimate mosquito population dynamics under current and projected future climate scenarios for multiple locations across the country. Trends in mosquito abundance were variable by location, however, an extension of the vector activity periods, and by extension disease risk, was almost uniformly observed. Importantly, mid-summer decreases in abundance may be off-set by shorter extrinsic incubation periods resulting in a greater proportion of infective mosquitoes. Quantitative descriptions of the effect of temperature on the virus and mosquito are critical to developing models of future disease risk.

  17. Robust Change Vector Analysis (RCVA) for multi-sensor very high resolution optical satellite data

    NASA Astrophysics Data System (ADS)

    Thonfeld, Frank; Feilhauer, Hannes; Braun, Matthias; Menz, Gunter

    2016-08-01

    The analysis of rapid land cover/land use changes by means of remote sensing is often based on data acquired under varying and occasionally unfavorable conditions. In addition, such analyses frequently use data acquired by different sensor systems. These acquisitions often differ with respect to sun position and sensor viewing geometry which lead to characteristic effects in each image. These differences may have a negative impact on reliable change detection. Here, we propose an approach called Robust Change Vector Analysis (RCVA), aiming to mitigate these effects. RCVA is an improvement of the widely-used Change Vector Analysis (CVA), developed to account for pixel neighborhood effects. We used a RapidEye and Kompsat-2 cross-sensor change detection test to demonstrate the efficiency of RCVA. Our analysis showed that RCVA results in fewer false negatives as well as false positives when compared to CVA under similar test conditions. We conclude that RCVA is a powerful technique which can be utilized to reduce spurious changes in bi-temporal change detection analyses based on high- or very-high spatial resolution imagery.

  18. Performance evaluation of random forest and support vector regressions in natural hazard change detection

    NASA Astrophysics Data System (ADS)

    Eisavi, Vahid; Homayouni, Saeid

    2016-10-01

    Information on land use and land cover changes is considered as a foremost requirement for monitoring environmental change. Developing change detection methodology in the remote sensing community is an active research topic. However, to the best of our knowledge, no research has been conducted so far on the application of random forest regression (RFR) and support vector regression (SVR) for natural hazard change detection from high-resolution optical remote sensing observations. Hence, the objective of this study is to examine the use of RFR and SVR to discriminate between changed and unchanged areas after a tsunami. For this study, RFR and SVR were applied to two different pilot coastlines in Indonesia and Japan. Two different remotely sensed data sets acquired by Quickbird and Ikonos sensors were used for efficient evaluation of the proposed methodology. The results demonstrated better performance of SVM compared to random forest (RF) with an overall accuracy higher by 3% to 4% and kappa coefficient by 0.05 to 0.07. Using McNemar's test, statistically significant differences (Z≥1.96), at the 5% significance level, between the confusion matrices of the RF classifier and the support vector classifier were observed in both study areas. The high accuracy of change detection obtained in this study confirms that these methods have the potential to be used for detecting changes due to natural hazards.

  19. Foehn Winds in the McMurdo Dry Valleys, Antarctica: A Driver of Environmental Change?

    NASA Astrophysics Data System (ADS)

    Speirs, J. C.; McGowan, H. A.

    2011-12-01

    Foehn winds are warm, dry and gusty winds that commonly occur in many mid-latitude mountainous regions. Detailed investigations into foehn winds in polar regions and their effects on landscape processes however, are rare. Foehn events are frequently experienced in the McMurdo Dry Valleys, Antarctica where they are caused by topographic modification of strong southwesterly airflow that is forced by synoptic-scale cyclones in the Amundsen/Ross Sea region. Recent research has shown that the intra and interannual frequency and intensity of foehn events varies in response to the position and frequency of these synoptic cyclones. The El Niño Southern Oscillation and the Southern Annular Mode are known sources of circulation anomalies in this region, and the frequency of foehn winds in the McMurdo Dry Valleys has been linked to these sources of climate variability. Despite the high frequency of foehn events in the McMurdo Dry Valleys, the influence of foehn winds on landscape processes of this polar desert is not well understood. Here we present research that integrates numerical weather model products, automatic weather station observations, stream discharge data and remote sensing techniques to quantify the influence of foehn winds on environmental processes in the McMurdo Dry Valleys. During summer, foehn winds play a critical role in raising air and soil temperatures above 0°C. Sublimation, meltwater generation and snow persistence are also shown to be significantly influenced by foehn winds and their affects on landscape processes which persist for several days after foehn wind cessation. Foehn winds play a large role in keeping the valleys snow and ice free. Any precipitation that does fall is quickly evaporated/sublimated by foehn winds. We conclude that foehn winds in the McMurdo Dry Valleys are the major cause of contemporary landscape change and aridity.

  20. The fossil wind structures of Eta Carinae: changes across one 5.54-yr cycle

    NASA Astrophysics Data System (ADS)

    Gull, Theodore R.; Madura, Thomas I.; Teodoro, Mairan; Clementel, Nicola; Corcoran, Michael; Damineli, Augusto; Groh, Jose H.; Hamaguchi, Kenji; Hillier, D. John; Moffat, Anthony F. J.; Richardson, Noel D.; Weigelt, Gerd; Lindler, Don; Feggans, Keith

    2016-11-01

    Eta Carinae, the closest, active, massive binary containing a highly unstable Luminous Blue Variable, exhibits expanding, compressed wind shells, seen in emission, that are spatially and spectrally resolved by Hubble Space Telescope/Space Telescope Imaging Spectrograph. Starting in 2009 June, these structures were mapped across its 5.54-yr, highly elliptical, binary orbit to follow temporal changes in the light of [Fe III] 4659 Å and [Fe II] 4815 Å. The emissions trace portions of fossil wind shells, that were formed by wind-wind interactions across each cycle. Over the high-ionization state, dense arcs, photoionized by far-ultraviolet radiation from the hot secondary, are seen in [Fe III]. Other arcs, ionized by mid-ultraviolet radiation from the primary star, are seen in [Fe II]. The [Fe III] structures tend to be interior to [Fe II] structures that trace extensive, less disturbed primary wind. During the brief periastron passage when the secondary plunges deep into the primary's extremely dense wind, on the far side of primary star, high-ionization [Fe III] structures fade and reappear in [Fe II]. Multiple fossil wind structures were traced across the 5.7-yr monitoring interval. The strong similarity of the expanding [Fe II] shells suggests that the wind and photoionization properties of the massive binary have not changed substantially from one orbit to the next over the past several orbital cycles. These observations trace structures that can be used to test 3D hydrodynamical and radiative-transfer models of massive, interacting winds. They also provide a baseline for following future changes in η Car, especially of its winds and photoionization properties.

  1. Changing distribution patterns of canine vector borne diseases in Italy: leishmaniosis vs. dirofilariosis

    PubMed Central

    Otranto, Domenico; Capelli, Gioia; Genchi, Claudio

    2009-01-01

    Ecological and climatic changes, human and animal population dynamics are among the several factors that have favoured the spread or the (re)introduction and establishment of "novel" vector species and pathogens they transmit in previously disease-free geographical areas. As key examples of the changing pattern of distribution of canine vector borne diseases (CVBDs), the current distribution of canine leishmaniosis (CanL) by Leishmania infantum and dirofilariosis by Dirofilaria immitis causing heart worm disease (HW) in Italy is discussed on the basis of retrospective historical reports until the 90's and later on until 2009. For long time, D. immitis has been considered mainly present along the Po River Valley and northward areas, while L. infantum in south-central Italy and Sicily and Sardinia. Comparison of current available and historical data (up to 1989) confirms that HW and CanL, although with different prevalence rates, have been changing their distribution patterns in Italy as a result of many biological and ecological factors, including those related to vector distribution and introduction of new species (e.g. the Asian tiger mosquito Aedes albopictus, a competent vector of D. immitis). New autochthonous foci of HW in southern Italy (i.e. Apulia and Calabria regions) have recently been reported. Although analysing retrospective data may represent a difficult task, the "paradigm" about the dual distribution of HW and CanL in northern and southern Italy cannot yet be considered valid. The research needs for managing HW and CanL in previously uninfected areas are discussed. PMID:19426441

  2. Impact of climate change in the epidemiology of vector-borne diseases in domestic carnivores.

    PubMed

    Beugnet, F; Chalvet-Monfray, K

    2013-12-01

    Vector-borne diseases are medically important in humans and animals but were long considered tropical and known to first affect production animals. This is no longer true and we can see today that they are common in domestic animals and that they are also present in temperate countries, especially in Europe. In recent years, an increase in the diagnosis of vector borne diseases among humans and animals has been observed, which may partly due to the development of diagnostic tools. Their study requires exchanges and collaborations between the many actors involved, especially since the epidemiology seems to be constantly evolving. The veterinary practitioner is the first one to notice the emergence of cases and to implement prevention measures. He also acts as a sentinel to alert epidemiologists. Many factors can explain the epidemiological changes, i.e. all human factors, such as the increase in commercial transportation, but also owners traveling with their pet during the holidays, the development of "outdoor" activities, the increase of individual housings with gardens; to these human factors must be added the ignorance of the risks, linked to animals in general and to wildlife in particular; then the environmental changes: forest fragmentation, establishment of parks; the increase of wild mammal populations (deer, carnivores, rodents, etc.); finally, climate changes. Climate change is a reality which may explain the increase of density of arthropod vectors, but also of their hosts, changes in periods of activity and variations in geographical distribution. The authors show the proof of the climate modifications and then explain how it has an impact in Europe on ticks, mosquitoes, sandflies and even fleas. They conclude on the practical consequences for veterinary practitioners, especially with the diagnosis of parasitic diseases or diseases in areas where they usually do not occur. However, not any epidemiological modification should be linked to climate change

  3. Climate Change, Public Health, and Decision Support: The New Threat of Vector-borne Disease

    NASA Astrophysics Data System (ADS)

    Grant, F.; Kumar, S.

    2011-12-01

    Climate change and vector-borne diseases constitute a massive threat to human development. It will not be enough to cut emissions of greenhouse gases-the tide of the future has already been established. Climate change and vector-borne diseases are already undermining the world's efforts to reduce extreme poverty. It is in the best interests of the world leaders to think in terms of concerted global actions, but adaptation and mitigation must be accomplished within the context of local community conditions, resources, and needs. Failure to act will continue to consign developed countries to completely avoidable health risks and significant expense. Failure to act will also reduce poorest of the world's population-some 2.6 billion people-to a future of diminished opportunity. Northrop Grumman has taken significant steps forward to develop the tools needed to assess climate change impacts on public health, collect relevant data for decision making, model projections at regional and local levels; and, deliver information and knowledge to local and regional stakeholders. Supporting these tools is an advanced enterprise architecture consisting of high performance computing, GIS visualization, and standards-based architecture. To address current deficiencies in local planning and decision making with respect to regional climate change and its effect on human health, our research is focused on performing a dynamical downscaling with the Weather Research and Forecasting (WRF) model to develop decision aids that translate the regional climate data into actionable information for users. For the present climate WRF was forced with the Max Planck Institute European Center/Hamburg Model version 5 (ECHAM5) General Circulation Model 20th century simulation. For the 21th century climate, we used an ECHAM5 simulation with the Special Report on Emissions (SRES) A1B emissions scenario. WRF was run in nested mode at spatial resolution of 108 km, 36 km and 12 km and 28 vertical levels

  4. Support Vector Machines for Multitemporal and Multisensor Change Detection in a Mining Area

    NASA Astrophysics Data System (ADS)

    Hecheltjen, Antje; Waske, Bjorn; Thonfeld, Frank; Braun, Matthias; Menz, Gunter

    2010-12-01

    Long-term change detection often implies the challenge of incorporating multitemporal data from different sensors. Most of the conventional change detection algorithms are designed for bi-temporal datasets from the same sensors detecting only the existence of changes. The labeling of change areas remains a difficult task. To overcome such drawbacks, much attention has been given lately to algorithms arising from machine learning, such as Support Vector Machines (SVMs). While SVMs have been applied successfully for land cover classifications, the exploitation of this approach for change detection is still in its infancy. Few studies have already proven the applicability of SVMs for bi- and multitemporal change detection using data from one sensor only. In this paper we demonstrate the application of SVM for multitemporal and -sensor change detection. Our study site covers lignite open pit mining areas in the German state North Rhine-Westphalia. The dataset consists of bi-temporal Landsat data and multi-temporal ERS SAR data covering two time slots (2001 and 2009). The SVM is conducted using the IDL program imageSVM. Change is deduced from one time slot to the next resulting in two change maps. In contrast to change detection, which is based on post-classification comparison, change detection is seen here as a specific classification problem. Thus, changes are directly classified from a layer-stack of the two years. To reduce the number of change classes, we created a change mask using the magnitude of Change Vector Analysis (CVA). Training data were selected for different change classes (e.g. forest to mining or mining to agriculture) as well as for the no-change classes (e.g. agriculture). Subsequently, they were divided in two independent sets for training the SVMs and accuracy assessment, respectively. Our study shows the applicability of SVMs to classify changes via SVMs. The proposed method yielded a change map of reclaimed and active mines. The use of ERS SAR

  5. On the Improvement of Convergence Performance for Integrated Design of Wind Turbine Blade Using a Vector Dominating Multi-objective Evolution Algorithm

    NASA Astrophysics Data System (ADS)

    Wang, L.; Wang, T. G.; Wu, J. H.; Cheng, G. P.

    2016-09-01

    A novel multi-objective optimization algorithm incorporating evolution strategies and vector mechanisms, referred as VD-MOEA, is proposed and applied in aerodynamic- structural integrated design of wind turbine blade. In the algorithm, a set of uniformly distributed vectors is constructed to guide population in moving forward to the Pareto front rapidly and maintain population diversity with high efficiency. For example, two- and three- objective designs of 1.5MW wind turbine blade are subsequently carried out for the optimization objectives of maximum annual energy production, minimum blade mass, and minimum extreme root thrust. The results show that the Pareto optimal solutions can be obtained in one single simulation run and uniformly distributed in the objective space, maximally maintaining the population diversity. In comparison to conventional evolution algorithms, VD-MOEA displays dramatic improvement of algorithm performance in both convergence and diversity preservation for handling complex problems of multi-variables, multi-objectives and multi-constraints. This provides a reliable high-performance optimization approach for the aerodynamic-structural integrated design of wind turbine blade.

  6. The effect of solar wind dynamic pressure changes on low and mid-latitude magnetic records

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Ginskey, M.; Petrinec, S.; Le, G.

    1992-06-01

    Magnetic records from low- and mid-latitude stations have been examined to determine their response to solar wind pressure changes. The best correlation between ground level changes and the change in the square root of the solar wind dynamic pressure occurs for stations at latitudes from 15 to 30 deg such as Tahiti, Honolulu, San Juan and Midway. The horizontal component of the field changes on average 16.5 nT for each change of 1(nPa) exp 1/2 of the square root of dynamic pressure. This is 50 percent greater than the vacuum model of Tsyganenko would predict for a nonconducting earth and therefore what would be expected for a perfectly conducting interior. Thus, low- and mid-latitude ground level response to solar wind pressure changes is dominated by the variation of the strength and location of the magnetopause current system and the corresponding induced currents within the earth rather than ionospheric current sources.

  7. Modelling potential changes in marine biogeochemistry due to large-scale offshore wind farms

    NASA Astrophysics Data System (ADS)

    van der Molen, Johan; Rees, Jon; Limpenny, Sian

    2013-04-01

    Large-scale renewable energy generation by offshore wind farms may lead to changes in marine ecosystem processes through the following mechanism: 1) wind-energy extraction leads to a reduction in local surface wind speeds; 2) these lead to a reduction in the local wind wave height; 3) as a consequence there's a reduction in SPM resuspension and concentrations; 4) this results in an improvement in under-water light regime, which 5) may lead to increased primary production, which subsequently 6) cascades through the ecosystem. A three-dimensional coupled hydrodynamics-biogeochemistry model (GETM_ERSEM) was used to investigate this process for a hypothetical wind farm in the central North Sea, by running a reference scenario and a scenario with a 10% reduction (as was found in a case study of a small farm in Danish waters) in surface wind velocities in the area of the wind farm. The ERSEM model included both pelagic and benthic processes. The results showed that, within the farm area, the physical mechanisms were as expected, but with variations in the magnitude of the response depending on the ecosystem variable or exchange rate between two ecosystem variables (3-28%, depending on variable/rate). Benthic variables tended to be more sensitive to the changes than pelagic variables. Reduced, but noticeable changes also occurred for some variables in a region of up to two farm diameters surrounding the wind farm. An additional model run in which the 10% reduction in surface wind speed was applied only for wind speeds below the generally used threshold of 25 m/s for operational shut-down showed only minor differences from the run in which all wind speeds were reduced. These first results indicate that there is potential for measurable effects of large-scale offshore wind farms on the marine ecosystem, mainly within the farm but for some variables up to two farm diameters away. However, the wave and SPM parameterisations currently used in the model are crude and need to be

  8. An appraisal of the full geomagnetic vector in wind-blown sediments - does it have a future? (Invited)

    NASA Astrophysics Data System (ADS)

    Kravchinsky, V. A.

    2013-12-01

    Recent progress in the relative paleointensity (RPI) studies of the loess and paleosol deposits of China demonstrate the applicability of the technique in some sections. The PRI record of the Lingtai section (Pan et al., 2001) is mostly comparable to the reference curves of Valet et al. (2005) and Channel et al. (2009). Climate driven chemical alterations of remnant magnetization signal is additionally suggested as an explanation to the intervals of dissimilarities. The newest results of Yang et al. (2012) reveal more complex situations. At the Baoji section, where pedogenesis is relatively weak, the RPI results might possibly suggest a reflection of global paleointensity variations. The record from the Xifeng section, where pedogenesis is stronger, does not reveal any interpretable results. Studies of the Luochuan section suggest that chemical remnant magnetization is strongly linked to the pedogenesis process implying serious constrains on the interpretation of the high resolution paleomagnetic records from the paleosol and the underlying loess intervals (Liu and Zhang, 2013). At the same time, recent paleomagnetic and mineral magnetic investigations indicate that the Alaskan loess is an excellent geomagnetic direction recorder in the upper Matuyama and Brunhes epoch (Evans et al., 2011). The fine structure of the geomagnetic field can be accurately evaluated for the intervals, which are reliably dated with modern techniques (Jensen, 2013). The strong magnetic signal carried by magnetite from the igneous rock sources overwrites complexities caused by the pedogenesis process, therefore our newly obtained Alaskan geomagnetic record is the first candidate for both reliable paleointensity data set from the wind-blown sediments and the fine structure of the full geoomagnetic vector (inclination, declination, RPI). High resolution geochronology and high latitude position of the Alaskan loess help resolving the fine features of the geomagnetic excursions which are

  9. Metabolic changes in rat urine after acute paraquat poisoning and discriminated by support vector machine.

    PubMed

    Wen, Congcong; Wang, Zhiyi; Zhang, Meiling; Wang, Shuanghu; Geng, Peiwu; Sun, Fa; Chen, Mengchun; Lin, Guanyang; Hu, Lufeng; Ma, Jianshe; Wang, Xianqin

    2016-01-01

    Paraquat is quick-acting and non-selective, killing green plant tissue on contact; it is also toxic to human beings and animals. In this study, we developed a urine metabonomic method by gas chromatography-mass spectrometry to evaluate the effect of acute paraquat poisoning on rats. Pattern recognition analysis, including both partial least squares discriminate analysis and principal component analysis revealed that acute paraquat poisoning induced metabolic perturbations. Compared with the control group, the levels of benzeneacetic acid and hexadecanoic acid of the acute paraquat poisoning group (intragastric administration 36 mg/kg) increased, while the levels of butanedioic acid, pentanedioic acid, altronic acid decreased. Based on these urinary metabolomics data, support vector machine was applied to discriminate the metabolomic change of paraquat groups from the control group, which achieved 100% classification accuracy. In conclusion, metabonomic method combined with support vector machine can be used as a useful diagnostic tool in paraquat-poisoned rats.

  10. Effect of sudden solar wind dynamic pressure changes at subauroral latitudes: Change in magnetic field

    SciTech Connect

    Le, G.; Russell, C.T.; Petrinec, S.M.; Ginskey, M. )

    1993-03-01

    The observations obtained during the International Magnetospheric Study (IMS) from the magnetometers of the IGS network extending from Cambridge, England, to Tromso, Norway, are used to study the response of subauroral current systems to sudden changes in solar wind dynamic pressure. Observations show that the response is very strong at subauroral latitudes. The preliminary response in the H component is a brief, small increase in the dayside moring sector and a decrease in the afternoon and night sectors. The main response in the horizontal field (the H and D components) is toward the pole except in the dayside morning sector. The inferred ionospheric current is mainly a circulatory system flowing counterclockwise when viewed form the north pole everywhere at subauroral latitudes except the dayside morning sector. 29 refs., 12 figs.

  11. Mars Pathfinder Landing Site: Evidence for a Change in Wind Regime from Lander and Orbiter Data

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Kraft, Michael D.; Kuzmin, Ruslan O.; Bridges, Nathan T.

    2000-01-01

    Surface features related to the wind are observed in the vicinity of the Mars Pathfinder (MPR landing site data from the lander and in data from orbit by the Viking Orbiter and Mars Global Surveyor missions. Features seen from the surface include wind tails associated with small rocks, barchanoid duneforms, ripplelike patterns, and ventifact flutes cut into some rocks. Features seen from orbit include wind tails associated with impact craters, ridges inferred to be duneforms, and modified crater rims interpreted to have been eroded and mantled by windblown material. The orientations of these features show two prevailing directions. One is inferred to represent winds from the northeast, which is consistent with strongest winds predicted by a general circulation model to occur during the Martian northern winter under current conditions. A second wind blowing from the ESE was responsible for modifying the crater rims and cutting some of the ventifacts. The two wind regimes could reflect a change in climate related to Mars' obliquity or some other, unknown factor. Regardless of the cause, the MPF area has been subjected to a complex pattern of winds and supply of small particles, and the original surface formed by sedimentary processes from Tiu and Ares Vallis flooding events has been modified by repeated burial and exhumation.

  12. Wave spectral response to sudden changes in wind direction in finite-depth waters

    NASA Astrophysics Data System (ADS)

    Aijaz, Saima; Rogers, W. Erick; Babanin, Alexander V.

    2016-07-01

    The response of a wind-sea spectrum to sudden changes in wind directions of 180° and 90° is investigated. Numerical simulations using the third-generation wave spectral model SWAN have been undertaken at micro timescales of 30 s and fine spatial resolution of less than 10 m. The results have been validated against the wave data collected during the field campaign at Lake George, Australia. The newly implemented 'ST6' physics in the SWAN model has been evaluated using a selection of bottom-friction terms and the two available functions for the nonlinear energy transfer: (1) exact solution of the nonlinear term (XNL), and (2) discrete interactions approximation (DIA) that parameterizes the nonlinear term. Good agreement of the modelled data is demonstrated directly with the field data and through the known experimental growth curves obtained from the extensive Lake George data set. The modelling results show that of the various combinations of models tested, the ST6/XNL model provides the most reliable computations of integral and spectral wave parameters. When the winds and waves are opposing (180° wind turn), the XNL is nearly twice as fast in the aligning the young wind-sea with the new wind direction than the DIA. In this case, the young wind-sea gradually decouples from the old waves and forms a new secondary peak. Unlike the 180° wind turn, there is no decoupling in the 90° wind turn and the entire spectrum rotates smoothly in the new direction. In both cases, the young wind-sea starts developing in the new wind direction within 10 min of the wind turn for the ST6 while the directional response of the default physics lags behind with a response time that is nearly double of ST6. The modelling results highlight the differences in source term balance among the different models in SWAN. During high wind speeds, the default settings provide a larger contribution from the bottom-friction dissipation than the whitecapping. In contrast, the whitecapping

  13. Multiple support vector machines for land cover change detection: An application for mapping urban extensions

    NASA Astrophysics Data System (ADS)

    Nemmour, Hassiba; Chibani, Youcef

    The reliability of support vector machines for classifying hyper-spectral images of remote sensing has been proven in various studies. In this paper, we investigate their applicability for land cover change detection. First, SVM-based change detection is presented and performed for mapping urban growth in the Algerian capital. Different performance indicators, as well as a comparison with artificial neural networks, are used to support our experimental analysis. In a second step, a combination framework is proposed to improve change detection accuracy. Two combination rules, namely, Fuzzy Integral and Attractor Dynamics, are implemented and evaluated with respect to individual SVMs. Recognition rates achieved by individual SVMs, compared to neural networks, confirm their efficiency for land cover change detection. Furthermore, the relevance of SVM combination is highlighted.

  14. Wind-tunnel investigation of the powered low-speed longitudinal aerodynamics of the Vectored-Engine-Over (VEO) wing fighter configuration

    NASA Technical Reports Server (NTRS)

    Paulson, J. W.; Whitten, P. D.; Stumpfl, S. C.

    1982-01-01

    A wind-tunnel investigation incorporating both static and wind-on testing was conducted in the Langley 4- by 7-Meter Tunnel to determine the effects of vectored thrust along with spanwise blowing on the low-speed aerodynamics of an advanced fighter configuration. Data were obtained over a large range of thrust coefficients corresponding to takeoff and landing thrust settings for many nozzle configurations. The complete set of static thrust data and the complete set of longitudinal aerodynamic data obtained in the investigation are presented. These data are intended for reference purposes and, therefore, are presented without analysis or comment. The analysis of the thrust-induced effects found in the investigation are not discussed.

  15. DOE SBIR Phase II Final Technical Report - Assessing Climate Change Effects on Wind Energy

    SciTech Connect

    Whiteman, Cameron; Capps, Scott

    2014-11-05

    Specialized Vertum Partners software tools were prototyped, tested and commercialized to allow wind energy stakeholders to assess the uncertainties of climate change on wind power production and distribution. This project resulted in three commercially proven products and a marketing tool. The first was a Weather Research and Forecasting Model (WRF) based resource evaluation system. The second was a web-based service providing global 10m wind data from multiple sources to wind industry subscription customers. The third product addressed the needs of our utility clients looking at climate change effects on electricity distribution. For this we collaborated on the Santa Ana Wildfire Threat Index (SAWTi), which was released publicly last quarter. Finally to promote these products and educate potential users we released “Gust or Bust”, a graphic-novel styled marketing publication.

  16. An intercomparison of different topography effects on discrimination performance of fuzzy change vector analysis algorithm

    NASA Astrophysics Data System (ADS)

    Singh, Sartajvir; Talwar, Rajneesh

    2016-12-01

    Detection of snow cover changes is vital for avalanche hazard analysis and flood flashes that arise due to variation in temperature. Hence, multitemporal change detection is one of the practical mean to estimate the snow cover changes over larger area using remotely sensed data. There have been some previous studies that examined how accuracy of change detection analysis is affected by different topography effects over Northwestern Indian Himalayas. The present work emphases on the intercomparison of different topography effects on discrimination performance of fuzzy based change vector analysis (FCVA) as change detection algorithm that includes extraction of change-magnitude and change-direction from a specific pixel belongs multiple or partial membership. The qualitative and quantitative analysis of the proposed FCVA algorithm is performed under topographic conditions and topographic correction conditions. The experimental outcomes confirmed that in change category discrimination procedure, FCVA with topographic correction achieved 86.8% overall accuracy and 4.8% decay (82% of overall accuracy) is found in FCVA without topographic correction. This study suggests that by incorporating the topographic correction model over mountainous region satellite imagery, performance of FCVA algorithm can be significantly improved up to great extent in terms of determining actual change categories.

  17. Limited change in dune mobility in response to a large decrease in wind power in semi-arid northern China since the 1970s

    USGS Publications Warehouse

    Mason, J.A.; Swinehart, J.B.; Lu, H.; Miao, X.; Cha, P.; Zhou, Y.

    2008-01-01

    The climatic controls on dune mobility, especially the relative importance of wind strength, remain incompletely understood. This is a key research problem in semi-arid northern China, both for interpreting past dune activity as evidence of paleoclimate and for predicting future environmental change. Potential eolian sand transport, which is approximately proportional to wind power above the threshold for sand entrainment, has decreased across much of northern China since the 1970s. Over the same period, effective moisture (ratio of precipitation to potential evapotranspiration) has not changed significantly. This "natural experiment" provides insight on the relative importance of wind power as a control on dune mobility in three dunefields of northern China (Mu Us, Otindag, and Horqin), although poorly understood and potentially large effects of human land use complicate interpretation. Dune forms in these three regions are consistent with sand transport vectors inferred from weather station data, suggesting that wind directions have remained stable and the stations adequately represent winds that shaped the dunes. The predicted effect of weaker winds since the 1970s would be dune stabilization, with lower sand transport rates allowing vegetation cover to expand. Large portions of all three dunefields remained stabilized by vegetation in the 1970s despite high wind power. Since the 1970s, trends in remotely sensed vegetation greenness and change in mobile dune area inferred from sequential Landsat images do indicate widespread dune stabilization in the eastern Mu Us region. On the other hand, expansion of active dunes took place farther west in the Mu Us dunefield and especially in the central Otindag dunefield, with little overall change in two parts of the Horqin dunes. Better ground truth is needed to validate the remote sensing analyses, but results presented here place limits on the relative importance of wind strength as a control on dune mobility in the

  18. SeaWinds Scatterometer Wind Vector Retrievals Within Hurricanes Using AMSR and NEXRAD to Perform Corrections for Precipitation Effects: Comparison of AMSR and NEXRAD Retrievals of Rain

    NASA Technical Reports Server (NTRS)

    Weissman, David E.; Hristova-Veleva, Svetla; Callahan, Philip

    2006-01-01

    The opportunity provided by satellite scatterometers to measure ocean surface winds in strong storms and hurricanes is diminished by the errors in the received backscatter (SIGMA-0) caused by the attenuation, scattering and surface roughening produced by heavy rain. Providing a good rain correction is a very challenging problem, particularly at Ku band (13.4 GHz) where rain effects are strong. Corrections to the scatterometer measurements of ocean surface winds can be pursued with either of two different methods: empirical or physical modeling. The latter method is employed in this study because of the availability of near simultaneous and collocated measurements provided by the MIDORI-II suite of instruments. The AMSR was designed to measure atmospheric water-related parameters on a spatial scale comparable to the SeaWinds scatterometer. These quantities can be converted into volumetric attenuation and scattering at the Ku-band frequency of SeaWinds. Optimal estimates of the volume backscatter and attenuation require a knowledge of the three dimensional distribution of reflectivity on a scale comparable to that of the precipitation. Studies selected near the US coastline enable the much higher resolution NEXRAD reflectivity measurements evaluate the AMSR estimates. We are also conducting research into the effects of different beam geometries and nonuniform beamfilling of precipitation within the field-of-view of the AMSR and the scatterometer. Furthermore, both AMSR and NEXRAD estimates of atmospheric correction can be used to produce corrected SIGMA-0s, which are then input to the JPL wind retrieval algorithm.

  19. Challenges in predicting climate and environmental effects on vector-borne disease episystems in a changing world.

    PubMed

    Tabachnick, W J

    2010-03-15

    Vector-borne pathogens cause enormous suffering to humans and animals. Many are expanding their range into new areas. Dengue, West Nile and Chikungunya have recently caused substantial human epidemics. Arthropod-borne animal diseases like Bluetongue, Rift Valley fever and African horse sickness pose substantial threats to livestock economies around the world. Climate change can impact the vector-borne disease epidemiology. Changes in climate will influence arthropod vectors, their life cycles and life histories, resulting in changes in both vector and pathogen distribution and changes in the ability of arthropods to transmit pathogens. Climate can affect the way pathogens interact with both the arthropod vector and the human or animal host. Predicting and mitigating the effects of future changes in the environment like climate change on the complex arthropod-pathogen-host epidemiological cycle requires understanding of a variety of complex mechanisms from the molecular to the population level. Although there has been substantial progress on many fronts the challenges to effectively understand and mitigate the impact of potential changes in the environment on vector-borne pathogens are formidable and at an early stage of development. The challenges will be explored using several arthropod-borne pathogen systems as illustration, and potential avenues to meet the challenges will be presented.

  20. Dynamics of Sylvatic Chagas Disease Vectors in Coastal Ecuador Is Driven by Changes in Land Cover

    PubMed Central

    Grijalva, Mario J.; Terán, David; Dangles, Olivier

    2014-01-01

    Background Chagas disease is a serious public health problem in Latin America where about ten million individuals show Trypanosoma cruzi infection. Despite significant success in controlling domiciliated triatomines, sylvatic populations frequently infest houses after insecticide treatment which hampers long term control prospects in vast geographical areas where vectorial transmission is endemic. As a key issue, the spatio-temporal dynamics of sylvatic populations is likely influenced by landscape yet evidence showing this effect is rare. The aim of this work is to examine the role of land cover changes in sylvatic triatomine ecology, based on an exhaustive field survey of pathogens, vectors, hosts, and microhabitat characteristics' dynamics. Methodology and Principal Findings The study was performed in agricultural landscapes of coastal Ecuador as a study model. Over one year, a spatially-randomized sampling design (490 collection points) allowed quantifying triatomine densities in natural, cultivated and domestic habitats. We also assessed infection of the bugs with trypanosomes, documented their microhabitats and potential hosts, and recorded changes in landscape characteristics. In total we collected 886 individuals, mainly represented by nymphal stages of one triatomine species Rhodnius ecuadoriensis. As main results, we found that 1) sylvatic triatomines had very high T. cruzi infection rates (71%) and 2) densities of T. cruzi-infected sylvatic triatomines varied predictably over time due to changes in land cover and occurrence of associated rodent hosts. Conclusion We propose a framework for identifying the factors affecting the yearly distribution of sylvatic T. cruzi vectors. Beyond providing key basic information for the control of human habitat colonization by sylvatic vector populations, our framework highlights the importance of both environmental and sociological factors in shaping the spatio-temporal population dynamics of triatomines. A better

  1. Detecting land-use/land-cover change in rural-urban fringe areas using extended change-vector analysis

    NASA Astrophysics Data System (ADS)

    He, Chunyang; Wei, Anni; Shi, Peijun; Zhang, Qiaofeng; Zhao, Yuanyuan

    2011-08-01

    Detecting land-use/land-cover (LULC) changes in rural-urban fringe areas (RUFAs) timely and accurately using satellite imagery is essential for land-use planning and management in China. Although traditional spectral-based change-vector analysis (CVA) can effectively detect LULC change in many cases, it encounters difficulties in RUFAs because of deficiencies in the spectral information of satellite images. To detect LULC changes in RUFAs effectively, this paper proposes an extended CVA approach that incorporates textural change information into the traditional spectral-based CVA. The extended CVA was applied to three different pilot RUFAs in China with different remotely sensed data, including Landsat Thematic Mapper (TM), China-Brazil Earth Resources Satellite (CBERS) and Advanced Land Observing Satellite (ALOS) images. The results demonstrated the improvement of the extended CVA compared to the traditional spectral-based CVA with the overall accuracy increased between 4.66% and 8.00% and the kappa coefficient increased between 0.10 and 0.15, respectively. The advantage of the extended CVA lies in its integration of both spectral and textural change information to detect LULC changes, allowing for effective discrimination of LULC changes that are spectrally similar but texturally different in RUFAs. The extended CVA has great potential to be widely used for LULC-change detection in RUFAs, which are often heterogeneous and fragmental in nature, with rich textural information.

  2. A change vector analysis technique for monitoring land cover changes in Copsa Mica, Romania, in the period 1985-2011.

    PubMed

    Vorovencii, Iosif

    2014-09-01

    During the communist regime, Romania's planned economy focused exclusively on production neglecting the environment protection. The lack of less polluting production technologies and of environmental protection measures led to excessive pollution in certain industrialized areas. This is the case of the town of Copsa Mica in Sibiu County, which in 1987 was considered one of the most polluted towns in Europe. The present study assesses the change vector analysis (CVA) technique using a Landsat Thematic Mapper (TM) image time series to monitor land cover changes caused by carbon black and heavy metal pollution. CVA was applied to the tasseled cap greenness (TCG) and tasseled cap brightness (TCB) indices, as well as to the Normalized Difference Vegetation Index (NDVI) and bare soil index (BI). Various maps were generated for the periods 1985-1994, 1994-2003, 2003-2011, and 1985-2011, and threshold values were determined for the detection of land cover change/no change. The change direction and magnitude values were cross-tabulated and classified. The technique was assessed based on the change versus no-change error matrix. The results show that in the area of Copsa Mica, land cover changes occurred because of a considerable decrease in the area affected by carbon black and heavy metal pollution. The CVA technique proved efficient in monitoring the land cover changes caused by pollution and especially by carbon black pollution. Soil pollution by heavy metals is reflected in the bare soil surfaces present in the imagery.

  3. ERS-1 scatterometer calibration and validation activities at ECMWF. B: From radar backscatter characteristics to wind vector solutions

    NASA Technical Reports Server (NTRS)

    Stoffelen, AD; Anderson, David L. T.; Woiceshyn, Peter M.

    1992-01-01

    Calibration and validation activities for the ERS-1 scatterometer were carried out at ECMWF (European Center for Medium range Weather Forecast) complementary to the 'Haltenbanken' field campaign off the coast of Norway. At a Numerical Weather Prediction (NWP) center a wealth of verifying data is available both in time and space. This data is used to redefine the wind retrieval procedure given the instrumental characteristics. It was found that a maximum likelihood estimation procedure to obtain the coefficients of a reformulated sigma deg to wind relationship should use radar measurements in logarithmic rather than physical space, and use winds as the wind components rather than wind speed and direction. Doing this, a much more accurate transfer function than the one currently operated by ESA was derived. Sigma deg measurement space shows no signature of a separation in an upwind solution cone and a downwind solution cone. As such signature was anticipated in ESA's wind direction ambiguity removal algorithm, reconsideration of the procedure is necessary. Despite the fact that revisions have to be made in the process of wind retrieval; a grid potential is shown for scatterometry in meteorology and climatology.

  4. Changes in the Burgers Vector of Perfect Dislocation Loops without Contact with the External Dislocations

    SciTech Connect

    Arakawa, K.; Hatanaka, M.; Mori, H.; Kuramoto, E.; Ono, K.

    2006-03-31

    We report the observations of a new type of changing process in the Burgers vector of dislocations by in situ transmission electron microscopy. Small interstitial-type perfect dislocation loops in bcc iron with diameters less than approximately 50 nm are transformed from a 1/2<111> loop to another 1/2<111> one or an energetically unfavorable <100> one; furthermore, a <100> loop is transformed to a 1/2<111> one. These transformations occurred on high-energy electron irradiation or simple heating without contact with external dislocations. The origin of these phenomena is discussed.

  5. Winds of Change: How Black Holes May Shape Galaxies

    NASA Astrophysics Data System (ADS)

    2010-03-01

    New observations from NASA's Chandra X-ray Observatory provide evidence for powerful winds blowing away from the vicinity of a supermassive black hole in a nearby galaxy. This discovery indicates that "average" supermassive black holes may play an important role in the evolution of the galaxies in which they reside. For years, astronomers have known that a supermassive black hole grows in parallel with its host galaxy. And, it has long been suspected that material blown away from a black hole - as opposed to the fraction of material that falls into it -- alters the evolution of its host galaxy. A key question is whether such "black hole blowback" typically delivers enough power to have a significant impact. Powerful relativistic jets shot away from the biggest supermassive black holes in large, central galaxies in clusters like Perseus are seen to shape their host galaxies, but these are rare. What about less powerful, less focused galaxy-scale winds that should be much more common? "We're more interested here in seeing what an "average"-sized supermassive black hole can do to its galaxy, not the few, really big ones in the biggest galaxies," said Dan Evans of the Massachusetts Institute of Technology who presented these results at the High Energy Astrophysics Division of the American Astronomical Society meeting in Kona, Hawaii. Evans and his colleagues used Chandra for five days to observe NGC 1068, one of the nearest and brightest galaxies containing a rapidly growing supermassive black hole. This black hole is only about twice as massive as the one in the center of our Galaxy, which is considered to be a rather ordinary size. The X-ray images and spectra obtained using Chandra's High Energy Transmission Grating Spectrometer (HETGS) showed that a strong wind is being driven away from the center of NGC 1068 at a rate of about a million miles per hour. This wind is likely generated as surrounding gas is accelerated and heated as it swirls toward the black hole. A

  6. Change in Hamiltonian general relativity from the lack of a time-like Killing vector field

    NASA Astrophysics Data System (ADS)

    Pitts, J. Brian

    2014-08-01

    In General Relativity in Hamiltonian form, change has seemed to be missing, defined only asymptotically, or otherwise obscured at best, because the Hamiltonian is a sum of first-class constraints and a boundary term and thus supposedly generates gauge transformations. Attention to the gauge generator G of Rosenfeld, Anderson, Bergmann, Castellani et al., a specially tuned sum of first-class constraints, facilitates seeing that a solitary first-class constraint in fact generates not a gauge transformation, but a bad physical change in electromagnetism (changing the electric field) or General Relativity. The change spoils the Lagrangian constraints, Gauss's law or the Gauss-Codazzi relations describing embedding of space into space-time, in terms of the physically relevant velocities rather than auxiliary canonical momenta. While Maudlin and Healey have defended change in GR much as G. E. Moore resisted skepticism, there remains a need to exhibit the technical flaws in the no-change argument. Insistence on Hamiltonian-Lagrangian equivalence, a theme emphasized by Mukunda, Castellani, Sugano, Pons, Salisbury, Shepley and Sundermeyer among others, holds the key. Taking objective change to be ineliminable time dependence, one recalls that there is change in vacuum GR just in case there is no time-like vector field ξα satisfying Killing's equation £ξgμν = 0, because then there exists no coordinate system such that everything is independent of time. Throwing away the spatial dependence of GR for convenience, one finds explicitly that the time evolution from Hamilton's equations is real change just when there is no time-like Killing vector. The inclusion of a massive scalar field is simple. No obstruction is expected in including spatial dependence and coupling more general matter fields. Hence change is real and local even in the Hamiltonian formalism. The considerations here resolve the Earman-Maudlin standoff over change in Hamiltonian General Relativity: the

  7. Impact of changing wind conditions on foraging and incubation success in male and female wandering albatrosses.

    PubMed

    Cornioley, Tina; Börger, Luca; Ozgul, Arpat; Weimerskirch, Henri

    2016-09-01

    Wind is an important climatic factor for flying animals as by affecting their locomotion, it can deeply impact their life-history characteristics. In the context of globally changing wind patterns, we investigated the mechanisms underlying recently reported increase in body mass of a population of wandering albatrosses (Diomedea exulans) with increasing wind speed over time. We built a foraging model detailing the effects of wind on movement statistics and ultimately on mass gained by the forager and mass lost by the incubating partner. We then simulated the body mass of incubating pairs under varying wind scenarios. We tracked the frequency at which critical mass leading to nest abandonment was reached to assess incubation success. We found that wandering albatrosses behave as time minimizers during incubation as mass gain was independent of any movement statistics but decreased with increasing mass at departure. Individuals forage until their energy requirements, which are determined by their body conditions, are fulfilled. This can come at the cost of their partner's condition as mass loss of the incubating partner depended on trip duration. This behaviour is consistent with strategies of long-lived species which favoured their own survival over their current reproductive attempt. In addition, wind speed increased ground speed which in turn reduced trip duration and males foraged further away than females at high ground speed. Contrasted against an independent data set, the simulation performed satisfactorily for males but less so for females under current wind conditions. The simulation predicted an increase in male body mass growth rate with increasing wind speed, whereas females' rate decreased. This trend may provide an explanation for the observed increase in mass of males but not of females. Conversely, the simulation predicted very few nest abandonments, which is in line with the high breeding success of this species and is contrary to the hypothesis that

  8. Impact of climate change on surface wind regime over the Peru-Chile upwelling region

    NASA Astrophysics Data System (ADS)

    Goubanova, K.; Echevin, V.; Dewitte, B.; Garreaud, R.; Terray, P.; Vrac, M.

    2009-04-01

    The ocean region off the Chile-Peru coast is characterized by upwelling of cold, nutrient-rich waters, which drives an exceptionally high biological productivity. This upwelling is induced by the persistent southerly winds along the coast that exhibit a coastal jet structure at intraseasonal scales. Recent climate change studies based on the coupled atmosphere-ocean general circulation models (AOGCM) show a strengthening of the large-scale southerlies along the subtropical coast that could lead to an increase in coastal upwelling. However the coastal jet events which represent a considerable source of the synoptic variability of the alongshore winds are characterized by horizontal scale comparable to a AOGCM grid cell size, and cannot be therefore explicitly resolved by the AOGCMs. In order to provide a regional estimate of the winds as predicted by the coarse-resolution AOGCMs, a statistical downscaling method based on multiple linear regression is proposed. Large-scale wind at 10 m and sea level pressure are chosen as the predictor variables for regional 10 m wind. The validation is performed in two steps. First, QuikSCAT and ERS satellite products and NCEP reanalysis for the period 1992-2006 are used to build and validate the statistical model for the present climate. Second, the model is validated under a warmer climate: it is applied to large-scale predictors extracted from HadCM3 AOGCM simulations for the A2 and B2 SRES scenarios (2071-2100); the downscaled wind is then compared with outputs of the PRECIS regional climate model, forced at its boundaries by the same HadCM3 scenarios. To assess climate change impact on the along-shore wind, the statistical downscaling is applied to two contrasted SRES scenarios, namely the so-called preindustrial and CO2 quadrupling. The outputs of the IPSL-CM4 AOGCM are used as predictors. Evolution of the along-shore wind regime with a focus on the change of the coastal jet characteristics is discussed. For this particular

  9. Environmental change and water-related, vector borne diseases in eastern Africa: the HEALTHY FUTURES project

    NASA Astrophysics Data System (ADS)

    Taylor, David; Kienberger, Stefan; Tompkins, Adrian

    2015-04-01

    Pathogens that spend time outside the human body, and any organisms involved in their transmission, have particular ecological requirements; as environment, including climate, conditions change, then the transmission characteristics of associated pathogens - and the diseases caused - are also likely to vary. Relationships between environment and health in many parts of the world remain poorly studied and are often overlooked, however. This is particularly the case in developing countries, because of budgetary and available expertise constraints. Moreover the relationship is often confounded by other factors. These other factors contribute to human vulnerability, and thus to the overall disease risk due to environmental change. This presentation will highlight the importance of environmental, including climate, change information to a better understanding of the risks to health of projected future environmental changes, and to the more efficient and effective use of scarce health resources in the developing world. The paper will focus on eastern Africa, and in particular the health effects of future projected environmental change impacts on water-related, vector borne diseases in the East African Community region. Moreover the paper will highlight how the EU FP7-funded project HEALTHY FUTURES is, through a broadly-based, integrative approach that distinguishes environmental change-induced health hazard from health risk aims to support the health decisions making process, thereby attempting to help mitigate negative health impacts.

  10. Past and future wind changes over the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Chavaillaz, Y.; Codron, F.; Kageyama, M.

    2013-12-01

    Mid-latitude westerlies are a major component of the atmospheric circulation, and their response to climate change will determine changes in precipitation, storms, and ocean circulation and CO2 uptake. In this study, we analyse, mainly in terms of jet stream position, the behaviour of the southern westerlies for a future climate, obtained after stabilisation of the RCP4.5 scenario, as well as for the Last Glacial Maximum (LGM, 21 000 yr ago), which is the last past cold extreme with about opposite global temperature change from the future one. We use the models from the CMIP5-PMIP3 archive. The a priori guess would be that the behaviour of the westerly jet stream would be similar when examining its changes from LGM to pre-industrial (PI) con- ditions and from PI to RCP4.5, i.e. in both cases a poleward shift in response to global warming. While this is true for all models in the future case, the LGM shows instead little or inconsistent jet shifts, because of a strong cooling over Antarctica during the LGM. We show that the behavior of the jets in both cases can be quantitatively reproduced using two indices of temperature changes in the Tropics and the high latitudes.

  11. Variations of helium abundance in the solar wind and its changes across IP shocks

    NASA Astrophysics Data System (ADS)

    Durovcova, Tereza; Cagas, Petr; Safrankova, Jana; Nemecek, Zdenek; Zastenker, Georgy N.

    2016-04-01

    The relative abundance of helium in the solar wind mediates the physical processes ongoing at the Sun surface. The ratio of alpha and proton densities is believed to characterize the source of the currently observed solar wind stream. Thus abrupt changes of this ratio are usually associated with encounters of the boundary between flux tubes emanating from different sources. However, a preliminary analysis of the data from the BMSW instrument (the Spektr-R spacecraft) shows that the He abundance can rapidly vary over much shorter time scales and we suggest that the differential motion of the proton and alpha solar wind components provides the driving energy for turbulence that is able to create the observed fast changes of the alpha/proton ratio. The differential velocity would significantly change across interplanetary shocks, whereas the density ratio does not. Thus, to separate the changes corresponding to flux tube crossings from those caused by turbulence within these flux tubes, we analyze the fast variations of helium/proton ratios prior to and after IP shocks. We compare measurements of two spacecraft (Spektr-R around the Earth, and Wind in L1 point) across the interplanetary shocks and focus on the variations of the helium abundance in a connection with the changes of the alpha/proton differential velocity. The two-case study is complemented with statistical analysis of correlations between related quantities.

  12. The impact of changes in the Antarctic wind field on the Southern Ocean sea ice

    NASA Astrophysics Data System (ADS)

    Haid, Verena; Iovino, Dorotea; Masina, Simona

    2016-04-01

    Satellite observations show an enlargement of the sea ice extent of the Southern Ocean in the last decades. A possible trigger for the increase is a change in the atmospheric circulation, which leads to a southward shift and intensification of the westerlies around Antarctica. We performed a sensitivity study with an eddy-permitting sea ice-ocean model forced by ERA-Interim data. We compare a set of numerical simulations with simple manipulations of the wind velocities in the forcing data and investigate the response of sea ice and on-shelf water properties. In our results, increases of the zonal wind component lead to the onset of deep convection in the Weddell Sea within 10 years (with one exception) and a reduction of sea ice. Manipulations of the meridional wind component can lead to an increase of ice extent and volume, but only if regions of strengthened northward wind alternate with regions of increased southward wind. The convergent drift against the shoreline is necessary to thicken the sea ice. Without it, enhanced northward drift leads to an exhanced ice extent during winter but combined with a loss of sea ice thickness which entails a strongly reduced ice extent during summer. For increases of the westward/eastward wind component at the Antarctic coastline, the on-shelf water temperatures increase/decrease due to Ekman pumping. Except for regions with more southerly winds, the manipulated forcing in all cases increases the sea ice production at the coastline and therefore the on-shelf waters are more saline. After a period of 10 years in all the experiments the increased wind results in a higher density of the on-shelf water column.

  13. Hydroxychloroquine Screening Alert: Change is in the Wind.

    PubMed

    Marmor, Michael F

    2017-02-01

    Recent studies have changed the management of hydroxychloroquine retinopathy. This editorial outlines a new standard. Estimate dose by real weight, staying below 5 mg/kg. Asian patients may show initial damage outside the parafovea. Renal disease, maculopathy, and tamoxifen are major risk factors. Proper screening allows long usage and avoids bull's eye retinopathy.

  14. [Physiological response of corn seedlings to changes of wind-sand flow strength].

    PubMed

    Zhao, Ha-lin; Li, Jin; Zhou, Rui-lian; Qu, Hao; Yun, Jian-ying; Pan, Cheng-chen

    2015-01-01

    Corn seedlings are often harmed by strong wind-sand in the spring in semi-arid wind-sand area of west of Northeast China. In order to understand physiological response mechanisms of the corn seedlings to wind-sand damage, the changes in MDA content, membrane permeability, protective enzymes activities and osmotic regulation substances at 0 (CK) , 6, 9, 12, 15 and 18 m . s-1 wind speed (wind-sand flow strength: 0, 1.00, 28.30, 63.28, 111.82 and 172.93 g . cm-1 . min-1, respectively) for 10 min duration were studied during the spring, 2013 in the Horqin Sand Land of Inner Mongolia. The results showed that effects of wind-sand flow blowing on the RWC of the corn seedling were lighter in the 6-12 m . s-1 treatments, but the RWC decreased by 19.0% and 18.7% in the 15 m . s-1 and 18 m . s-1 treatments compared to the CK, respectively. The MDA content tended to decline with increasing the wind-sand flow strength, and decreased by 35.0% and 39.0% in the 15 m . s-1 and 18 m . s-1 treatments compared to the CK, respectively. The membrane permeability increased significantly with increasing the wind-sand flow strength, and increased by 191.3% and 187.8% in the 15 m . s-1 and 18 m . s-1 treatments compared to the CK, respectively. With the increase of wind-sand flow strength, SOD activities decreased and changes of CAT activities were not significant, only POD activities increased significantly, which played an important role in the process of scavenging reactive oxygen species and protecting cell membrane against damage. For lighter water stress caused, by wind-sand flow blowing, proline and soluble sugar did not play any role in osmotic adjustment, but the proline content increased by 11.4% and 24.5% in the 15 m . s-1 and 18 m . s-1 treatments compared to the CK, respectively, which played an important role in osmotic adjustment.

  15. An Ill Wind? Climate Change, Migration, and Health

    PubMed Central

    Barnett, Jon

    2012-01-01

    Background: Climate change is projected to cause substantial increases in population movement in coming decades. Previous research has considered the likely causal influences and magnitude of such movements and the risks to national and international security. There has been little research on the consequences of climate-related migration and the health of people who move. Objectives: In this review, we explore the role that health impacts of climate change may play in population movements and then examine the health implications of three types of movements likely to be induced by climate change: forcible displacement by climate impacts, resettlement schemes, and migration as an adaptive response. Methods: This risk assessment draws on research into the health of refugees, migrants, and people in resettlement schemes as analogs of the likely health consequences of climate-related migration. Some account is taken of the possible modulation of those health risks by climate change. Discussion: Climate-change–related migration is likely to result in adverse health outcomes, both for displaced and for host populations, particularly in situations of forced migration. However, where migration and other mobility are used as adaptive strategies, health risks are likely to be minimized, and in some cases there will be health gains. Conclusions: Purposeful and timely policy interventions can facilitate the mobility of people, enhance well-being, and maximize social and economic development in both places of origin and places of destination. Nevertheless, the anticipated occurrence of substantial relocation of groups and communities will underscore the fundamental seriousness of human-induced climate change. PMID:22266739

  16. Enhancement of the double flexible pace search threshold determination for change vector analysis

    NASA Astrophysics Data System (ADS)

    Azzouzi, S. A.; Vidal, A.; Bentounes, H. A.

    2015-04-01

    Remote sensing is one of the most reliable ways to monitor land use and land cover change of large areas. On the other hand, satellite images from different agencies are becoming accessible due to the new user dissemination policies. For that reason, interpretation of remotely sensed data in a spatiotemporal context is becoming a valuable research topic. In the present day, a map of change has a great significant for scientific purposes or planning and management applications. However, it is difficult to extract useful visual information from the large collection of available satellite images. For that reason, automatic or semi-automatic exploration is needed. One of the key stages in the change detection methods is threshold selection. This threshold determination problem has been addressed by several recent techniques based on Change Vector Analysis (CVA). Thus, this work provides a simple semi-automatic procedure that defines the change/no change condition and a comparative study will be involved together with the previous existing method called Double Flexible Pace Search (DFPS). This study uses Landsat Thematic Mapper scenes acquired on different dates in an Algerian region. First, some training data sets containing all possible classes of change are required and their respective supervised posterior probability maps for each scene are obtained. The selected supervised classifier is based on the Maximum Likelihood method. Then four training sets (two sets from each date) are chosen from their corresponding probability maps based on their spatial location in the original images. The optimal average will be obtained as an average of the thresholds obtained at every set. This work verifies that the proposed approach is effective on the selected area, providing improved change map results.

  17. Quantifying Grain Fall and Avalanche Dynamics Under Changing Wind Conditions on Barchan Dunes

    NASA Astrophysics Data System (ADS)

    Nield, J. M.; Wiggs, G.; Baddock, M. C.; Hipondoka, M.

    2015-12-01

    Dunes are constantly moved and shaped by the wind but avalanche patterns and grain fall dynamics are particularly difficult to quantify without disturbing the lee slope. Here we use terrestrial laser scanning (TLS) to measure surface change over minutes, hours and a week where wind directions vary and lee slope reworking occurs. Changes in topography are linked to high resolution measurements of three dimensional airflow patterns at the brink of the dune. Grain fall is identified within a zone approximately 0.9 m from the brink that is constantly eroded. Several different avalanche patterns occur that can be related to slope characteristics, wind direction and slope reworking. We find that during oblique winds, horn reworking can reduce the lee slope. When normal winds return, this slope takes longer to start avalanching, but when avalanches are finally initiated, they are catastrophic. Conversely, avalanches in the centre of the dune are typically discrete and follow similar trajectories. Our findings help elucidate dune mobility mechanics and pattern modifications at the storm event scale.

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

    NASA Astrophysics Data System (ADS)

    Burgin, Laura; Ekström, Marie; Dessai, Suraje

    2017-01-01

    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.

  19. Titan's rotation reveals an internal ocean and changing zonal winds

    USGS Publications Warehouse

    Lorenz, R.D.; Stiles, B.W.; Kirk, R.L.; Allison, M.D.; Del Marmo, P.P.; Iess, L.; Lunine, J.I.; Ostro, S.J.; Hensley, S.

    2008-01-01

    Cassini radar observations of Saturn's moon Titan over several years show that its rotational period is changing and is different from its orbital period. The present-day rotation period difference from synchronous spin leads to a shift of ???0.36?? per year in apparent longitude and is consistent with seasonal exchange of angular momentum between the surface and Titan's dense superrotating atmosphere, but only if Titan's crust is decoupled from the core by an internal water ocean like that on Europa.

  20. Implications of climate change on wind erosion of agricultural lands in the Columbia Plateau

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change may impact soil health and productivity as a result of accelerated or decelerated rates of erosion. Previous studies suggest a greater risk of wind erosion on arid and semi-arid lands due to loss of biomass under a future warmer climate. There have been no studies conducted to assess ...

  1. Winds of Change: Charting the Course for IT in the Twenty-First Century

    ERIC Educational Resources Information Center

    Hawkins, Brian L.

    2007-01-01

    In the spring of 2005, the author, the retiring president of EDUCAUSE, was asked to be the keynote speaker at the EDUCAUSE Western Regional Conference. The conference theme was "Winds of Change: Charting the Course for Technology in Challenging Times." What that brought to his mind was the era of the great sailing ships of the eighteenth and…

  2. Climate change influences on global distributions of dengue and chikungunya virus vectors.

    PubMed

    Campbell, Lindsay P; Luther, Caylor; Moo-Llanes, David; Ramsey, Janine M; Danis-Lozano, Rogelio; Peterson, A Townsend

    2015-04-05

    Numerous recent studies have illuminated global distributions of human cases of dengue and other mosquito-transmitted diseases, yet the potential distributions of key vector species have not been incorporated integrally into those mapping efforts. Projections onto future conditions to illuminate potential distributional shifts in coming decades are similarly lacking, at least outside Europe. This study examined the global potential distributions of Aedes aegypti and Aedes albopictus in relation to climatic variation worldwide to develop ecological niche models that, in turn, allowed anticipation of possible changes in distributional patterns into the future. Results indicated complex global rearrangements of potential distributional areas, which--given the impressive dispersal abilities of these two species--are likely to translate into actual distributional shifts. This exercise also signalled a crucial priority: digitization and sharing of existing distributional data so that models of this sort can be developed more rigorously, as present availability of such data is fragmentary and woefully incomplete.

  3. Titan's rotation reveals an internal ocean and changing zonal winds.

    PubMed

    Lorenz, Ralph D; Stiles, Bryan W; Kirk, Randolph L; Allison, Michael D; Del Marmo, Paolo Persi; Iess, Luciano; Lunine, Jonathan I; Ostro, Steven J; Hensley, Scott

    2008-03-21

    Cassini radar observations of Saturn's moon Titan over several years show that its rotational period is changing and is different from its orbital period. The present-day rotation period difference from synchronous spin leads to a shift of approximately 0.36 degrees per year in apparent longitude and is consistent with seasonal exchange of angular momentum between the surface and Titan's dense superrotating atmosphere, but only if Titan's crust is decoupled from the core by an internal water ocean like that on Europa.

  4. Seasonal changes in the apparent position of the Sun as elementary applications of vector operations

    NASA Astrophysics Data System (ADS)

    Levine, Jonathan

    2014-11-01

    Many introductory courses in physics face an unpleasant chicken-and-egg problem. One might choose to introduce students to physical quantities such as velocity, acceleration, and momentum in over-simplified one-dimensional applications before introducing vectors and their manipulation; or one might first introduce vectors as mathematical objects and defer demonstration of their physical utility. This paper offers a solution to this pedagogical problem: elementary vector operations can be used without mechanics concepts to understand variations in the solar latitude, duration of daylight, and orientation of the rising and setting Sun. I show how sunrise and sunset phenomena lend themselves to exercises with scalar products, vector products, unit vectors, and vector projections that can be useful for introducing vector analysis in the context of physics.

  5. Climate change, warm Gulf waters and westerly wind shear, and Hurricane Katrina

    NASA Astrophysics Data System (ADS)

    Sun, D. S.

    The present year experienced several strong hurricanes intensifying in the Gulf of Mexico before making landfall and severely damaging the Gulf States especially Hurricane Katrina Here we show that increasing trend of sea surface temperature SST and decreasing vertical wind shear since 1995 over the Gulf may be attributed to climate change and provide favorable conditions for the recent increase in hurricane activity especially the 2005 hurricanes Higher SST anomaly at the right side of storm track induced the increase in surface heat fluxes which corresponds to the deepening of hurricane minimum central pressure A phase lag of about two days is found between SST increase and significant deepening of hurricane central pressure Our results suggest that in addition to the magnitude of vertical wind shear the effects of westerly from easterly wind shear on the intensification of hurricane may need to be separated and westerly environmental wind shear is conducive to hurricane development Warmer SST is found to correspond to the increase of vertical wind shear over the Gulf of Mexico

  6. [Impact of changes in the environment on vector-transmitted diseases].

    PubMed

    Mouchet, J; Carnevale, P

    1997-01-01

    We have defined the relationship between infectious diseases and environmental conditions and considered the development of this relationship to its current situation, where human intervention is occurring more often and is becoming more aggressive. The increase in the transport of freight and passengers by air has allowed parasite vectors to spread quickly and easily over large distances. Every country can now be reached from any other country within a couple of days. Usually, foreign species are unable to establish themselves and to persist in the new environment; but the recent arrival of Aedes albopictus in Albania, Italy and the Americas is a cause for concern. Demographic pressure has increased the need for land and the exploitation of new areas leads to large changes in the vegetation. The classic example of this man-made damage is the destruction of tropical forest in Western Africa, but the destruction of herbaceous vegetation, such as papyrus, in East Africa, could also have serious epidemiological consequences. Streams and rivers have been managed for power production and irrigation. The use of dams, both large and small, and the culture of rice in paddy-fields produces large expanses of water which are suitable breeding grounds for mosquitoes and snails, the vectors of human diseases such as malaria and schistosomiasis in sub-Saharan Africa. They are, however, of lesser importance in Asia and the Americas. Urbanization imposes a set of very similar structures on a specific rural environment. The effect of these two factors on each other determines the pathologies associated with each town. The suburban area is a specific environment where both urban and rural diseases occur and are made worse by poor hygiene conditions (waste, sewage, etc.). However, not all man-made changes to the environment cause a deterioration in public health. Urban and agricultural development projects must consider these issues and should use medical and environmental studies to

  7. Catastrophic wind damage to North American forests and the potential impact of climate change.

    PubMed

    Peterson, C J

    2000-11-15

    Catastrophic winds from tornadoes and downbursts are a major cause of natural disturbance in forests of eastern North America, accounting for thousands of hectares of disturbed area annually. Wind disturbance shows substantial regional variation, decreasing from the mid-west to the east and from the south-east to New England. In terms of the relative importance among these types of storms, more forest damage results from tornadoes in the south-east and mid-west, while downbursts are the most important type of wind disturbance in the Great Lakes area. Downbursts vary widely in size, but large ones can damage thousands of hectares, while tornadoes are much smaller, seldom affecting more than several hundred hectares. Tornadoes cause the most severe wind disturbances. Site characteristics such as physiography, soil moisture, and soil depth; stand characteristics like density and canopy roughness; and tree characteristics such as size, species, rooting depth, and wood strength, are the factors most recognized as influencing damage patterns. The consequences of wind damage to forests, such as change in environmental conditions, density, size structure, species composition, and successional status, occur on both immediate (hours-to-days) and long-term (months-to-decades) time scales. Most wind disturbances result in the post-disturbance vegetation being comprised of surviving canopy trees, and varying amounts of sprouts, released understory stems, and new seedlings. Stand size structure is usually reduced, and successional status of a forest is often advanced. Diversity can be either increased or decreased, depending on the measure of abundance used to calculate diversity. Because tornadoes and downbursts are in part products of thermodynamic climatic circumstances, they may be affected by anticipated changes in climatic conditions as the 21st century progresses. However, the current understanding of tornado and downburst formation from supercell storms is very

  8. Cytoplasmic pH Dynamics in Maize Pulvinal Cells Induced by Gravity Vector Changes1[w

    PubMed Central

    Johannes, Eva; Collings, David A.; Rink, Jochen C.; Allen, Nina Strömgren

    2001-01-01

    In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pHc) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291–1298). The question arises whether pHc has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pHc in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pHc changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pHc changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pHc has an important role in the early signaling pathways of maize stem gravitropism. PMID:11553740

  9. Cytoplasmic pH dynamics in maize pulvinal cells induced by gravity vector changes

    NASA Technical Reports Server (NTRS)

    Johannes, E.; Collings, D. A.; Rink, J. C.; Allen, N. S.; Brown, C. S. (Principal Investigator)

    2001-01-01

    In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pH(c)) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291-1298). The question arises whether pH(c) has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pH(c) in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pH(c) changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pH(c) changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pH(c) has an important role in the early signaling pathways of maize stem gravitropism.

  10. A Bacterial Parasite Effector Mediates Insect Vector Attraction in Host Plants Independently of Developmental Changes

    PubMed Central

    Orlovskis, Zigmunds; Hogenhout, Saskia A.

    2016-01-01

    Parasites can take over their hosts and trigger dramatic changes in host appearance and behavior that are typically interpreted as extended phenotypes that promote parasite survival and fitness. For example, Toxoplasma gondii is thought to manipulate the behaviors of infected rodents to aid transmission to cats and parasitic trematodes of the genus Ribeiroia alter limb development in their amphibian hosts to facilitate predation of the latter by birds. Plant parasites and pathogens also reprogram host development and morphology. However, whereas some parasite-induced morphological alterations may have a direct benefit to the fitness of the parasite and may therefore be adaptive, other host alterations may be side effects of parasite infections having no adaptive effects on parasite fitness. Phytoplasma parasites of plants often induce the development of leaf-like flowers (phyllody) in their host plants, and we previously found that the phytoplasma effector SAP54 generates these leaf-like flowers via the degradation of plant MADS-box transcription factors (MTFs), which regulate all major aspects of development in plants. Leafhoppers prefer to reproduce on phytoplasma-infected and SAP54-trangenic plants leading to the hypothesis that leafhopper vectors are attracted to plants with leaf-like flowers. Surprisingly, here we show that leafhopper attraction occurs independently of the presence of leaf-like flowers. First, the leafhoppers were also attracted to SAP54 transgenic plants without leaf-like flowers and to single leaves of these plants. Moreover, leafhoppers were not attracted to leaf-like flowers of MTF-mutant plants without the presence of SAP54. Thus, the primary role of SAP54 is to attract leafhopper vectors, which spread the phytoplasmas, and the generation of leaf-like flowers may be secondary or a side effect of the SAP54-mediated degradation of MTFs. PMID:27446117

  11. Scanning of wind turbine upwind conditions: numerical algorithm and first applications

    NASA Astrophysics Data System (ADS)

    Calaf, Marc; Cortina, Gerard; Sharma, Varun; Parlange, Marc B.

    2014-11-01

    Wind turbines still obtain in-situ meteorological information by means of traditional wind vane and cup anemometers installed at the turbine's nacelle, right behind the blades. This has two important drawbacks: 1-turbine misalignment with the mean wind direction is common and energy losses are experienced; 2-the near-blade monitoring does not provide any time to readjust the profile of the wind turbine to incoming turbulence gusts. A solution is to install wind Lidar devices on the turbine's nacelle. This technique is currently under development as an alternative to traditional in-situ wind anemometry because it can measure the wind vector at substantial distances upwind. However, at what upwind distance should they interrogate the atmosphere? A new flexible wind turbine algorithm for large eddy simulations of wind farms that allows answering this question, will be presented. The new wind turbine algorithm timely corrects the turbines' yaw misalignment with the changing wind. The upwind scanning flexibility of the algorithm also allows to track the wind vector and turbulent kinetic energy as they approach the wind turbine's rotor blades. Results will illustrate the spatiotemporal evolution of the wind vector and the turbulent kinetic energy as the incoming flow approaches the wind turbine under different atmospheric stability conditions. Results will also show that the available atmospheric wind power is larger during daytime periods at the cost of an increased variance.

  12. A case study of effects of atmospheric boundary layer turbulence, wind speed, and stability on wind farm induced temperature changes using observations from a field campaign

    NASA Astrophysics Data System (ADS)

    Xia, Geng; Zhou, Liming; Freedman, Jeffrey M.; Roy, Somnath Baidya; Harris, Ronald A.; Cervarich, Matthew Charles

    2016-04-01

    Recent studies using satellite observations show that operational wind farms in west-central Texas increase local nighttime land surface temperature (LST) by 0.31-0.70 °C, but no noticeable impact is detected during daytime, and that the diurnal and seasonal variations in the magnitude of this warming are likely determined by those in the magnitude of wind speed. This paper further explores these findings by using the data from a year-long field campaign and nearby radiosonde observations to investigate how thermodynamic profiles and surface-atmosphere exchange processes work in tandem with the presence of wind farms to affect the local climate. Combined with satellite data analyses, we find that wind farm impacts on LST are predominantly determined by the relative ratio of turbulence kinetic energy (TKE) induced by the wind turbines compared to the background TKE. This ratio explains not only the day-night contrast of the wind farm impact and the warming magnitude of nighttime LST over the wind farms, but also most of the seasonal variations in the nighttime LST changes. These results indicate that the diurnal and seasonal variations in the turbine-induced turbulence relative to the background TKE play an essential role in determining those in the magnitude of LST changes over the wind farms. In addition, atmospheric stability determines the sign and strength of the net downward heat transport as well as the magnitude of the background TKE. The study highlights the need for better understanding of atmospheric boundary layer and wind farm interactions, and for better parameterizations of sub-grid scale turbulent mixing in numerical weather prediction and climate models.

  13. Calcium mobilizations in response to changes in the gravity vector in Arabidopsis seedlings: possible cellular mechanisms.

    PubMed

    Tatsumi, Hitoshi; Toyota, Masatsugu; Furuichi, Takuya; Sokabe, Masahiro

    2014-01-01

    Gravity influences the growth direction of higher plants. Changes in the gravity vector (gravistimulation) immediately promote the increase in the cytoplasmic free calcium ion concentration ([Ca(2+)]c) in Arabidopsis (Arabidopsis thaliana) seedlings. When the seedlings are gravistimulated by reorientation at 180°, a transient two peaked (biphasic) [Ca(2+)]c-increase arises in their hypocotyl and petioles. Parabolic flights (PFs) can generate a variety of gravity-stimuli, and enables us to measure gravity-induced [Ca(2+)]c-increases without specimen rotation, which demonstrate that Arabidopsis seedlings possess a rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes into Ca(2+) signals on a sub-second timescale. Hypergravity by centrifugation (20 g or 300 g) also induces similar transient [Ca(2+)]c-increases. In this review, we propose models for possible cellular processes of the garavi-stimulus-induced [Ca(2+)]c-increase, and evaluate those by examining whether the model fits well with the kinetic parameters derived from the [Ca(2+)]c-increases obtained by applying gravistimulus with different amplitudes and time sequences.

  14. Calcium mobilizations in response to changes in the gravity vector in Arabidopsis seedlings

    PubMed Central

    Tatsumi, Hitoshi; Toyota, Masatsugu; Furuichi, Takuya; Sokabe, Masahiro

    2014-01-01

    Gravity influences the growth direction of higher plants. Changes in the gravity vector (gravistimulation) immediately promote the increase in the cytoplasmic free calcium ion concentration ([Ca2+]c) in Arabidopsis (Arabidopsis thaliana) seedlings. When the seedlings are gravistimulated by reorientation at 180°, a transient two peaked (biphasic) [Ca2+]c-increase arises in their hypocotyl and petioles. Parabolic flights (PFs) can generate a variety of gravity-stimuli, and enables us to measure gravity-induced [Ca2+]c-increases without specimen rotation, which demonstrate that Arabidopsis seedlings possess a rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes into Ca2+ signals on a sub-second timescale. Hypergravity by centrifugation (20 g or 300 g) also induces similar transient [Ca2+]c-increases. In this review, we propose models for possible cellular processes of the garavi-stimulus-induced [Ca2+]c-increase, and evaluate those by examining whether the model fits well with the kinetic parameters derived from the [Ca2+]c-increases obtained by applying gravistimulus with different amplitudes and time sequences. PMID:25763612

  15. Change in the direction of electric wind from a wire electrode tilted relative to a grounded plane

    NASA Astrophysics Data System (ADS)

    Elagin, I. A.; Begal', D. I.; Ashikhmin, I. A.; Stishkov, Yu. K.

    2017-01-01

    We report on experimental investigations of the structure of electric (ionic) wind in the wire-versus-plane electrode system with a constant interelectrode gap and variable wire tilt angle relative to the plane. Characteristic wind velocity distributions were determined using a laser Doppler anemometry technique. It is established that the position of the narrow central jet of the wind significantly changes depending on the tilt of the corona-forming electrode.

  16. Climate Change and Spatiotemporal Distributions of Vector-Borne Diseases in Nepal – A Systematic Synthesis of Literature

    PubMed Central

    Dhimal, Meghnath; Ahrens, Bodo; Kuch, Ulrich

    2015-01-01

    Background Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases (VBDs), namely malaria, lymphatic filariasis, Japanese encephalitis, visceral leishmaniasis and dengue fever. There is increasing evidence about the impacts of climate change on VBDs especially in tropical highlands and temperate regions. Our aim is to explore whether the observed spatiotemporal distributions of VBDs in Nepal can be related to climate change. Methodology A systematic literature search was performed and summarized information on climate change and the spatiotemporal distribution of VBDs in Nepal from the published literature until December2014 following providing items for systematic review and meta-analysis (PRISMA) guidelines. Principal Findings We found 12 studies that analysed the trend of climatic data and are relevant for the study of VBDs, 38 studies that dealt with the spatial and temporal distribution of disease vectors and disease transmission. Among 38 studies, only eight studies assessed the association of VBDs with climatic variables. Our review highlights a pronounced warming in the mountains and an expansion of autochthonous cases of VBDs to non-endemic areas including mountain regions (i.e., at least 2,000 m above sea level). Furthermore, significant relationships between climatic variables and VBDs and their vectors are found in short-term studies. Conclusion Taking into account the weak health care systems and difficult geographic terrain of Nepal, increasing trade and movements of people, a lack of vector control interventions, observed relationships between climatic variables and VBDs and their vectors and the establishment of relevant disease vectors already at least 2,000 m above sea level, we conclude that climate change can intensify the risk of VBD epidemics in the mountain regions of Nepal if other non-climatic drivers of VBDs remain constant. PMID

  17. Effects of Southern Hemisphere Wind Changes on the Meridional Overturning Circulation in Ocean Models.

    PubMed

    Gent, Peter R

    2016-01-01

    Observations show that the Southern Hemisphere zonal wind stress maximum has increased significantly over the past 30 years. Eddy-resolving ocean models show that the resulting increase in the Southern Ocean mean flow meridional overturning circulation (MOC) is partially compensated by an increase in the eddy MOC. This effect can be reproduced in the non-eddy-resolving ocean component of a climate model, providing the eddy parameterization coefficient is variable and not a constant. If the coefficient is a constant, then the Southern Ocean mean MOC change is balanced by an unrealistically large change in the Atlantic Ocean MOC. Southern Ocean eddy compensation means that Southern Hemisphere winds cannot be the dominant mechanism driving midlatitude North Atlantic MOC variability.

  18. Engineering changes to the 0.1m cryogenic wind tunnel at Southampton University

    NASA Technical Reports Server (NTRS)

    Goodyer, M. J.

    1984-01-01

    The more important changes to the 0.1 m cryogenic wind tunnel since its completion in 1977 are outlined. These include detailed improvements in the fan drive to allow higher speeds, and the provision of a test section leg suitable for use with a magnetic suspension and balance system. The instrumentation, data logging, data reduction and tunnel controls were also improved and modernized. A tunnel performance summary is given.

  19. Response of the Martian environment to solar wind dynamic pressure change

    NASA Astrophysics Data System (ADS)

    Modolo, R.; Leblanc, F.; Chaufray, J. Y.; Curry, S.; Leclercq, L.; Chanteur, G. M.; Savoini, P.

    2014-12-01

    The main structures of the solar wind plasma interaction with the upper atmosphere can be usually described using a steady state picture, however time-dependent effects play important roles. In the last couple of years sophisticated 3D simulation try to address the response of the induced magnetosphere and its escape to different time-dependent drivers. Modolo et al (2012) discussed about timescales required for the induced magnetosphere to recover from an IMF rotation. Ma et al (2013) used time-varying solar wind conditions (density and velocity enhancement) and concluded that the ionospheric/atmospheric system reach a new equilibrium in few hours. We use a 3D parallel multi-species hybrid simulation model to study the response of the induced magnetosphere to a time-varying solar wind dynamic pressure. The hybrid model (Modolo et al, 2014, in prep) includes crustal fields, a ionospheric chemistry scheme and uses a 3D description of the Martian thermosphere (Chaufray et al, 2014) and exosphere (Yagi et al, 2012). The impact of a solar wind dynamic pressure change on plasma boundaries is discussed. A special attention is focused on the time-varying energy deposition in the upper atmosphere by O+ ions precipitation as well as the escape flux of planetary ions.

  20. The role of heating, winds, and topography on sea level changes in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Zhang, Jinting; Kelly, Kathryn A.; Thompson, LuAnne

    2016-05-01

    Seasonal and interannual-to-decadal variations of large-scale altimetric sea surface height (SSH) owing to surface heating and wind forcing in the presence of topography are investigated using simplified models. The dominant forcing mechanisms are time scale dependent. On the seasonal time scale, locally forced thermosteric height explains most of the SSH variance north of 18°N. First-mode linear long baroclinic Rossby waves forced by changes in the winds and eastern boundary conditions explain most of the variance between 10°N and 15°N and are also important east of Greenland. On interannual-to-decadal time scales, local thermosteric height remains important at several locations in the middle and high latitudes. A topographic Sverdrup response explains interannual-to-decadal SSH between 53°N and 63°N east of Greenland. Farther south, the linear Rossby wave model explains SSH variations on interannual-to-decadal time scales between 30°N and 50°N from mid-basin to the eastern boundary. Propagation of the eastern boundary condition into the interior dominates the interannual-to-decadal SSH signals south of 30°N. The effect from NAO-related heat flux on SSH is small, but forcing the topographic Sverdrup models with NAO-regressed winds gives slightly better agreement with the observed SSH in the subpolar gyre on interannual-to-decadal time scales than using the full winds.

  1. Support vector machines for detecting age-related changes in running kinematics.

    PubMed

    Fukuchi, Reginaldo K; Eskofier, Bjoern M; Duarte, Marcos; Ferber, Reed

    2011-02-03

    Age-related changes in running kinematics have been reported in the literature using classical inferential statistics. However, this approach has been hampered by the increased number of biomechanical gait variables reported and subsequently the lack of differences presented in these studies. Data mining techniques have been applied in recent biomedical studies to solve this problem using a more general approach. In the present work, we re-analyzed lower extremity running kinematic data of 17 young and 17 elderly male runners using the Support Vector Machine (SVM) classification approach. In total, 31 kinematic variables were extracted to train the classification algorithm and test the generalized performance. The results revealed different accuracy rates across three different kernel methods adopted in the classifier, with the linear kernel performing the best. A subsequent forward feature selection algorithm demonstrated that with only six features, the linear kernel SVM achieved 100% classification performance rate, showing that these features provided powerful combined information to distinguish age groups. The results of the present work demonstrate potential in applying this approach to improve knowledge about the age-related differences in running gait biomechanics and encourages the use of the SVM in other clinical contexts.

  2. Magnetohydrodynamic simulations of transient transpolar potential responses to solar wind density changes

    NASA Astrophysics Data System (ADS)

    Ober, D. M.; Wilson, G. R.; Burke, W. J.; Maynard, N. C.; Siebert, K. D.

    2007-10-01

    Magnetohydrodynamic (MHD) simulations are used to examine the response of the transpolar potential (ΦTP) to changes in the solar wind density during periods of constant solar wind electric field. For increases (decreases) in the solar wind density ΦTP responds immediately by increasing (decreasing) from the steady state values. In both cases the response of ΦTP is transient, decaying to near initial steady state values even when the density change persists. The magnitude of the ΦTP response is proportional to both the rate of erosion of the dayside magnetopause and the ionospheric Pedersen conductance. In our MHD simulations ΦTP is driven entirely by the dayside merging rate and is insensitive to changes in the nightside reconnection rate. The observed relationship between the modeled dayside merging rate and ΦTP is well characterized by an L-R circuit equation derived from integrating Faraday's Law around the Region 1 current loop. The inductive time constant for variations in the transpolar potential was found to be 6.5 (13) minutes for simulations using ionospheric Pedersen conductances of 6 (12) mhos. This corresponds in both cases to a magnetosphere-ionosphere inductance of 65 Henries. Observations of the transpolar potential derived using the assimilative mapping of ionospheric electrodynamics (AMIE) model are presented and shown to be consistent with the simulation results.

  3. Range expansion of the Bluetongue vector, Culicoides imicola, in continental France likely due to rare wind-transport events

    PubMed Central

    Jacquet, Stéphanie; Huber, Karine; Pagès, Nonito; Talavera, Sandra; Burgin, Laura E.; Carpenter, Simon; Sanders, Christopher; Dicko, Ahmadou H.; Djerbal, Mouloud; Goffredo, Maria; Lhor, Youssef; Lucientes, Javier; Miranda-Chueca, Miguel A.; Pereira Da Fonseca, Isabel; Ramilo, David W.; Setier-Rio, Marie-Laure; Bouyer, Jérémy; Chevillon, Christine; Balenghien, Thomas; Guis, Hélène; Garros, Claire

    2016-01-01

    The role of the northward expansion of Culicoides imicola Kieffer in recent and unprecedented outbreaks of Culicoides-borne arboviruses in southern Europe has been a significant point of contention. We combined entomological surveys, movement simulations of air-borne particles, and population genetics to reconstruct the chain of events that led to a newly colonized French area nestled at the northern foot of the Pyrenees. Simulating the movement of air-borne particles evidenced frequent wind-transport events allowing, within at most 36 hours, the immigration of midges from north-eastern Spain and Balearic Islands, and, as rare events, their immigration from Corsica. Completing the puzzle, population genetic analyses discriminated Corsica as the origin of the new population and identified two successive colonization events within west-Mediterranean basin. Our findings are of considerable importance when trying to understand the invasion of new territories by expanding species. PMID:27263862

  4. Range expansion of the Bluetongue vector, Culicoides imicola, in continental France likely due to rare wind-transport events.

    PubMed

    Jacquet, Stéphanie; Huber, Karine; Pagès, Nonito; Talavera, Sandra; Burgin, Laura E; Carpenter, Simon; Sanders, Christopher; Dicko, Ahmadou H; Djerbal, Mouloud; Goffredo, Maria; Lhor, Youssef; Lucientes, Javier; Miranda-Chueca, Miguel A; Pereira Da Fonseca, Isabel; Ramilo, David W; Setier-Rio, Marie-Laure; Bouyer, Jérémy; Chevillon, Christine; Balenghien, Thomas; Guis, Hélène; Garros, Claire

    2016-06-06

    The role of the northward expansion of Culicoides imicola Kieffer in recent and unprecedented outbreaks of Culicoides-borne arboviruses in southern Europe has been a significant point of contention. We combined entomological surveys, movement simulations of air-borne particles, and population genetics to reconstruct the chain of events that led to a newly colonized French area nestled at the northern foot of the Pyrenees. Simulating the movement of air-borne particles evidenced frequent wind-transport events allowing, within at most 36 hours, the immigration of midges from north-eastern Spain and Balearic Islands, and, as rare events, their immigration from Corsica. Completing the puzzle, population genetic analyses discriminated Corsica as the origin of the new population and identified two successive colonization events within west-Mediterranean basin. Our findings are of considerable importance when trying to understand the invasion of new territories by expanding species.

  5. Zoom in at African country level: potential climate induced changes in areas of suitability for survival of malaria vectors

    PubMed Central

    2014-01-01

    Background Predicting anopheles vectors’ population densities and boundary shifts is crucial in preparing for malaria risks and unanticipated outbreaks. Although shifts in the distribution and boundaries of the major malaria vectors (Anopheles gambiae s.s. and An. arabiensis) across Africa have been predicted, quantified areas of absolute change in zone of suitability for their survival have not been defined. In this study, we have quantified areas of absolute change conducive for the establishment and survival of these vectors, per African country, under two climate change scenarios and based on our findings, highlight practical measures for effective malaria control in the face of changing climatic patterns. Methods We developed a model using CLIMEX simulation platform to estimate the potential geographical distribution and seasonal abundance of these malaria vectors in relation to climatic factors (temperature, rainfall and relative humidity). The model yielded an eco-climatic index (EI) describing the total favourable geographical locations for the species. The EI values were classified and exported to a GIS package. Using ArcGIS, the EI shape points were clipped to the extent of Africa and then converted to a raster layer using Inverse Distance Weighted (IDW) interpolation method. Generated maps were then transformed into polygon-based geo-referenced data set and their areas computed and expressed in square kilometers (km2). Results Five classes of EI were derived indicating the level of survivorship of these malaria vectors. The proportion of areas increasing or decreasing in level of survival of these malaria vectors will be more pronounced in eastern and southern African countries than those in western Africa. Angola, Ethiopia, Kenya, Mozambique, Tanzania, South Africa and Zambia appear most likely to be affected in terms of absolute change of malaria vectors suitability zones under the selected climate change scenarios. Conclusion The potential shifts of

  6. Climate change, vector-borne disease and interdisciplinary research: social science perspectives on an environment and health controversy.

    PubMed

    Brisbois, Ben W; Ali, S Harris

    2010-12-01

    Over the last two decades, the science of climate change's theoretical impacts on vector-borne disease has generated controversy related to its methodological validity and relevance to disease control policy. Critical social science analysis, drawing on science and technology studies and the sociology of social movements, demonstrates consistency between this controversy and the theory that climate change is serving as a collective action frame for some health researchers. Within this frame, vector-borne disease data are interpreted as a symptom of climate change, with the need for further interdisiplinary research put forth as the logical and necessary next step. Reaction to this tendency on the part of a handful of vector-borne disease specialists exhibits characteristics of academic boundary work aimed at preserving the integrity of existing disciplinary boundaries. Possible reasons for this conflict include the leadership role for health professionals and disciplines in the envisioned interdiscipline, and disagreements over the appropriate scale of interventions to control vector-borne diseases. Analysis of the competing frames in this controversy also allows identification of excluded voices and themes, such as international political economic explanations for the health problems in question. A logical conclusion of this analysis, therefore, is the need for critical reflection on environment and health research and policy to achieve integration with considerations of global health equity.

  7. A parametric study of the behavior of the angular momentum vector during spin rate changes of rigid body spacecraft

    NASA Technical Reports Server (NTRS)

    Longuski, J. M.

    1982-01-01

    During a spin-up or spin-down maneuver of a spinning spacecraft, it is usual to have not only a constant body-fixed torque about the desired spin axis, but also small undesired constant torques about the transverse axes. This causes the orientation of the angular momentum vector to change in inertial space. Since an analytic solution is available for the angular momentum vector as a function of time, this behavior can be studied for large variations of the dynamic parameters, such as the initial spin rate, the inertial properties and the torques. As an example, the spin-up and spin-down maneuvers of the Galileo spacecraft was studied and as a result, very simple heuristic solutions were discovered which provide very good approximations to the parametric behavior of the angular momentum vector orientation.

  8. Simulated response of the Southern Ocean to wind changes: towards the role of mesoscale eddies

    NASA Astrophysics Data System (ADS)

    Patara, Lavinia; Böning, Claus; Biastoch, Arne

    2013-04-01

    The role of ocean mesoscale eddies in the Southern Ocean response to recent wind changes is explored with a suite of realistic global ocean simulations at increasing horizontal resolution. Southern Ocean mesoscale eddies are known to be critical in the meridional redistribution of tracers, and are suggested to affect how the Southern Ocean responds to wind changes, takes up heat, and exchanges CO2 with the atmosphere. By employing the ocean general circulation model NEMO-LIM, ocean simulations with horizontal resolutions of 1/2°, 1/4°, and 1/12°, i.e. ranging from non-eddying to eddy-resolving, are performed and compared. In particular, a "two-way" nesting technique is used to refine the ocean grid up to 1/12° in the Southern Ocean. The ocean models are forced with the CORE v.2 atmospheric reanalysis during the period 1948-2007, and companion experiments under a repeated-annual-cycle forcing are used to detect model spurious drifts. First, we assess the effect of explicitly simulated eddies on ocean mean properties. Mesoscale eddies are shown to modify the mixed layer depth and the upper-ocean density, with potential effects on the formation properties of Subantarctic Mode Waters. Second, we explore the role of mesoscale eddies in affecting the ocean circulation sensitivity to the sustained increase of Southern Hemisphere winds during the past decades. Whereas the non-eddying simulations exhibit large increases of the Antarctic Circumpolar Current transport, the 1/4° and 1/12° models are less sensitive to the wind increase, in better agreement with available observations. These results show a clear effect of model resolution on the Southern Ocean response to climate variability and change.

  9. Atmospheric teleconnections between the tropics and the Southern Hemisphere westerly winds during abrupt climate change

    NASA Astrophysics Data System (ADS)

    Markle, B. R.; Steig, E. J.; Buizert, C.; Schoenemann, S. W.; Bitz, C. M.; Fudge, T. J.; Pedro, J. B.; Ding, Q.; Jones, T. R.; White, J. W. C.; Sowers, T. A.

    2015-12-01

    Abrupt, large amplitude climate oscillations occurred in the North Atlantic region during the last deglaciation and glacial period. Antarctic temperatures show a lagged and out-of-phase response, suggesting that these climate anomalies were propagated to the Southern Hemisphere high latitudes through changes in ocean circulation. Large changes in atmospheric circulation in the tropics accompanied abrupt North Atlantic climate change and modeling studies have predicted an atmospheric teleconnection between the tropics and the Southern Hemisphere westerly winds. However, consistent paleoclimate evidence for this tropical-high southern latitude atmospheric teleconnection has been lacking. Here we use a new high-resolution deuterium excess record from West Antarctica to show that moisture sources for Antarctic precipitation changed in phase with abrupt shifts in Northern Hemisphere climate, significantly before Antarctic temperature change. These results suggest that Southern Hemisphere mid-latitude storm tracks and westerly winds migrated north- and southwards within decades of rapid North Atlantic warming and cooling, respectively, and in parallel with the well-established migrations of the intertropical convergence zone. Both ocean and atmospheric processes, operating on different timescales, are critical to the global expression of abrupt climate change and this atmospheric link between the hemispheres may be important to the underlying dynamics.

  10. Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases.

    PubMed Central

    Gubler, D J; Reiter, P; Ebi, K L; Yap, W; Nasci, R; Patz, J A

    2001-01-01

    Diseases such as plague, typhus, malaria, yellow fever, and dengue fever, transmitted between humans by blood-feeding arthropods, were once common in the United States. Many of these diseases are no longer present, mainly because of changes in land use, agricultural methods, residential patterns, human behavior, and vector control. However, diseases that may be transmitted to humans from wild birds or mammals (zoonoses) continue to circulate in nature in many parts of the country. Most vector-borne diseases exhibit a distinct seasonal pattern, which clearly suggests that they are weather sensitive. Rainfall, temperature, and other weather variables affect in many ways both the vectors and the pathogens they transmit. For example, high temperatures can increase or reduce survival rate, depending on the vector, its behavior, ecology, and many other factors. Thus, the probability of transmission may or may not be increased by higher temperatures. The tremendous growth in international travel increases the risk of importation of vector-borne diseases, some of which can be transmitted locally under suitable circumstances at the right time of the year. But demographic and sociologic factors also play a critical role in determining disease incidence, and it is unlikely that these diseases will cause major epidemics in the United States if the public health infrastructure is maintained and improved. PMID:11359689

  11. Estimated Effects of Projected Climate Change on the Basic Reproductive Number of the Lyme Disease Vector Ixodes scapularis

    PubMed Central

    Radojevic´, Milka; Wu, Xiaotian; Duvvuri, Venkata R.; Leighton, Patrick A.; Wu, Jianhong

    2014-01-01

    Background: The extent to which climate change may affect human health by increasing risk from vector-borne diseases has been under considerable debate. Objectives: We quantified potential effects of future climate change on the basic reproduction number (R0) of the tick vector of Lyme disease, Ixodes scapularis, and explored their importance for Lyme disease risk, and for vector-borne diseases in general. Methods: We applied observed temperature data for North America and projected temperatures using regional climate models to drive an I. scapularis population model to hindcast recent, and project future, effects of climate warming on R0. Modeled R0 increases were compared with R0 ranges for pathogens and parasites associated with variations in key ecological and epidemiological factors (obtained by literature review) to assess their epidemiological importance. Results: R0 for I. scapularis in North America increased during the years 1971–2010 in spatio-temporal patterns consistent with observations. Increased temperatures due to projected climate change increased R0 by factors (2–5 times in Canada and 1.5–2 times in the United States), comparable to observed ranges of R0 for pathogens and parasites due to variations in strains, geographic locations, epidemics, host and vector densities, and control efforts. Conclusions: Climate warming may have co-driven the emergence of Lyme disease in northeastern North America, and in the future may drive substantial disease spread into new geographic regions and increase tick-borne disease risk where climate is currently suitable. Our findings highlight the potential for climate change to have profound effects on vectors and vector-borne diseases, and the need to refocus efforts to understand these effects. Citation: Ogden NH, Radojević M, Wu X, Duvvuri VR, Leighton PA, Wu J. 2014. Estimated effects of projected climate change on the basic reproductive number of the Lyme disease vector Ixodes scapularis. Environ Health

  12. Modelling the influence of predicted future climate change on the risk of wind damage within New Zealand's planted forests.

    PubMed

    Moore, John R; Watt, Michael S

    2015-08-01

    Wind is the major abiotic disturbance in New Zealand's planted forests, but little is known about how the risk of wind damage may be affected by future climate change. We linked a mechanistic wind damage model (ForestGALES) to an empirical growth model for radiata pine (Pinus radiata D. Don) and a process-based growth model (cenw) to predict the risk of wind damage under different future emissions scenarios and assumptions about the future wind climate. The cenw model was used to estimate site productivity for constant CO2 concentration at 1990 values and for assumed increases in CO2 concentration from current values to those expected during 2040 and 2090 under the B1 (low), A1B (mid-range) and A2 (high) emission scenarios. Stand development was modelled for different levels of site productivity, contrasting silvicultural regimes and sites across New Zealand. The risk of wind damage was predicted for each regime and emission scenario combination using the ForestGALES model. The sensitivity to changes in the intensity of the future wind climate was also examined. Results showed that increased tree growth rates under the different emissions scenarios had the greatest impact on the risk of wind damage. The increase in risk was greatest for stands growing at high stand density under the A2 emissions scenario with increased CO2 concentration. The increased productivity under this scenario resulted in increased tree height, without a corresponding increase in diameter, leading to more slender trees that were predicted to be at greater risk from wind damage. The risk of wind damage was further increased by the modest increases in the extreme wind climate that are predicted to occur. These results have implications for the development of silvicultural regimes that are resilient to climate change and also indicate that future productivity gains may be offset by greater losses from disturbances.

  13. Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau

    PubMed Central

    Munson, Seth M.; Belnap, Jayne; Okin, Gregory S.

    2011-01-01

    Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces. PMID:21368143

  14. Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau

    USGS Publications Warehouse

    Munson, Seth M.; Belnap, Jayne; Okin, Gregory S.

    2011-01-01

    Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.

  15. Evidence that implicit assumptions of ‘no evolution’ of disease vectors in changing environments can be violated on a rapid timescale

    PubMed Central

    Egizi, Andrea; Fefferman, Nina H.; Fonseca, Dina M.

    2015-01-01

    Projected impacts of climate change on vector-borne disease dynamics must consider many variables relevant to hosts, vectors and pathogens, including how altered environmental characteristics might affect the spatial distributions of vector species. However, many predictive models for vector distributions consider their habitat requirements to be fixed over relevant time-scales, when they may actually be capable of rapid evolutionary change and even adaptation. We examine the genetic signature of a spatial expansion by an invasive vector into locations with novel temperature conditions compared to its native range as a proxy for how existing vector populations may respond to temporally changing habitat. Specifically, we compare invasions into different climate ranges and characterize the importance of selection from the invaded habitat. We demonstrate that vector species can exhibit evolutionary responses (altered allelic frequencies) to a temperature gradient in as little as 7–10 years even in the presence of high gene flow, and further, that this response varies depending on the strength of selection. We interpret these findings in the context of climate change predictions for vector populations and emphasize the importance of incorporating vector evolution into models of future vector-borne disease dynamics. PMID:25688024

  16. Simulated effects of southern hemispheric wind changes on the Pacific oxygen minimum zone

    NASA Astrophysics Data System (ADS)

    Getzlaff, Julia; Dietze, Heiner; Oschlies, Andreas

    2016-01-01

    A coupled ocean biogeochemistry-circulation model is used to investigate the impact of observed past and anticipated future wind changes in the Southern Hemisphere on the oxygen minimum zone in the tropical Pacific. We consider the industrial period until the end of the 21st century and distinguish effects due to a strengthening of the westerlies from effects of a southward shift of the westerlies that is accompanied by a poleward expansion of the tropical trade winds. Our model results show that a strengthening of the westerlies counteracts part of the warming-induced decline in the global marine oxygen inventory. A poleward shift of the trade-westerlies boundary, however, triggers a significant decrease of oxygen in the tropical oxygen minimum zone. In a business-as-usual CO2 emission scenario, the poleward shift of the trade-westerlies boundary and warming-induced increase in stratification contribute equally to the expansion of suboxic waters in the tropical Pacific.

  17. Oceanography. Centennial changes in North Pacific anoxia linked to tropical trade winds.

    PubMed

    Deutsch, Curtis; Berelson, William; Thunell, Robert; Weber, Thomas; Tems, Caitlin; McManus, James; Crusius, John; Ito, Taka; Baumgartner, Timothy; Ferreira, Vicente; Mey, Jacob; van Geen, Alexander

    2014-08-08

    Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ(15)N) from multiple sediment cores. Increasing δ(15)N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ(15)N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean's largest anoxic zone will contract despite a global O2 decline.

  18. Evidence for link between modelled trends in Antarctic sea ice and underestimated westerly wind changes

    PubMed Central

    Purich, Ariaan; Cai, Wenju; England, Matthew H.; Cowan, Tim

    2016-01-01

    Despite global warming, total Antarctic sea ice coverage increased over 1979–2013. However, the majority of Coupled Model Intercomparison Project phase 5 models simulate a decline. Mechanisms causing this discrepancy have so far remained elusive. Here we show that weaker trends in the intensification of the Southern Hemisphere westerly wind jet simulated by the models may contribute to this disparity. During austral summer, a strengthened jet leads to increased upwelling of cooler subsurface water and strengthened equatorward transport, conducive to increased sea ice. As the majority of models underestimate summer jet trends, this cooling process is underestimated compared with observations and is insufficient to offset warming in the models. Through the sea ice-albedo feedback, models produce a high-latitude surface ocean warming and sea ice decline, contrasting the observed net cooling and sea ice increase. A realistic simulation of observed wind changes may be crucial for reproducing the recent observed sea ice increase. PMID:26842498

  19. Equatorial thermospheric wind changes during the solar cycle - Measurements at Arequipa, Peru, from 1983 to 1990

    NASA Technical Reports Server (NTRS)

    Biondi, M. A.; Meriwether, J. W., Jr.; Fejer, B. G.; Gonzalez, S. A.; Hallenbeck, D. C.

    1991-01-01

    Near-equatorial thermospheric wind velocities at Arequipa, Peru, are determined over about two-thirds of a solar cycle using Fabry-Perot interferometer measurements of Doppler shifts in the nightglow 630-nm emission line. Mean monthly nocturnal variations in the meridional and zonal wind components are calculated from the nightly data to remove short-term (day-to-day) variability as well as any additional changes introduced by the progression of the solar cycle. For most of the years, at the winter solstice, there is a weak (more than 100 m/s) transequatorial flow from the summer to the winter hemisphere in the early and the late night, with essentially zero velocities in between. At the equinoxes, an early-night poleward (southward) flow at solar minimum (1986) is replaced by an equatorward (northward) flow at solar maximum (1989-1990).

  20. Evidence for link between modelled trends in Antarctic sea ice and underestimated westerly wind changes

    NASA Astrophysics Data System (ADS)

    Purich, Ariaan; Cai, Wenju; England, Matthew H.; Cowan, Tim

    2016-02-01

    Despite global warming, total Antarctic sea ice coverage increased over 1979-2013. However, the majority of Coupled Model Intercomparison Project phase 5 models simulate a decline. Mechanisms causing this discrepancy have so far remained elusive. Here we show that weaker trends in the intensification of the Southern Hemisphere westerly wind jet simulated by the models may contribute to this disparity. During austral summer, a strengthened jet leads to increased upwelling of cooler subsurface water and strengthened equatorward transport, conducive to increased sea ice. As the majority of models underestimate summer jet trends, this cooling process is underestimated compared with observations and is insufficient to offset warming in the models. Through the sea ice-albedo feedback, models produce a high-latitude surface ocean warming and sea ice decline, contrasting the observed net cooling and sea ice increase. A realistic simulation of observed wind changes may be crucial for reproducing the recent observed sea ice increase.

  1. Evidence for link between modelled trends in Antarctic sea ice and underestimated westerly wind changes.

    PubMed

    Purich, Ariaan; Cai, Wenju; England, Matthew H; Cowan, Tim

    2016-02-04

    Despite global warming, total Antarctic sea ice coverage increased over 1979-2013. However, the majority of Coupled Model Intercomparison Project phase 5 models simulate a decline. Mechanisms causing this discrepancy have so far remained elusive. Here we show that weaker trends in the intensification of the Southern Hemisphere westerly wind jet simulated by the models may contribute to this disparity. During austral summer, a strengthened jet leads to increased upwelling of cooler subsurface water and strengthened equatorward transport, conducive to increased sea ice. As the majority of models underestimate summer jet trends, this cooling process is underestimated compared with observations and is insufficient to offset warming in the models. Through the sea ice-albedo feedback, models produce a high-latitude surface ocean warming and sea ice decline, contrasting the observed net cooling and sea ice increase. A realistic simulation of observed wind changes may be crucial for reproducing the recent observed sea ice increase.

  2. Centennial changes in North Pacific anoxia linked to tropical trade winds

    USGS Publications Warehouse

    Deutsch, Curtis; Berelson, William; Thunell, Robert; Weber, Thomas; Tems, Caitlin; McManus, James; Crusius, John; Ito, Taka; Baumgartner, Timothy; Ferreira, Vicente; Mey, Jacob; van Geen, Alexander

    2014-01-01

    Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ15N) from multiple sediment cores. Increasing δ15N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ15N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean’s largest anoxic zone will contract despite a global O2 decline.

  3. Aedes aegypti (L.) in Latin American and Caribbean region: With growing evidence for vector adaptation to climate change?

    PubMed

    Chadee, Dave D; Martinez, Raymond

    2016-04-01

    Within Latin America and the Caribbean region the impact of climate change has been associated with the effects of rainfall and temperature on seasonal outbreaks of dengue but few studies have been conducted on the impacts of climate on the behaviour and ecology of Aedes aegypti mosquitoes.This study was conducted to examine the adaptive behaviours currently being employed by A. aegypti mosquitoes exposed to the force of climate change in LAC countries. The literature on the association between climate and dengue incidence is small and sometimes speculative. Few laboratory and field studies have identified research gaps. Laboratory and field experiments were designed and conducted to better understand the container preferences, climate-associated-adaptive behaviour, ecology and the effects of different temperatures and light regimens on the life history of A. aegypti mosquitoes. A. aegypti adaptive behaviours and changes in container preferences demonstrate how complex dengue transmission dynamics is, in different ecosystems. The use of underground drains and septic tanks represents a major behaviour change identified and compounds an already difficult task to control A. aegypti populations. A business as usual approach will exacerbate the problem and lead to more frequent outbreaks of dengue and chikungunya in LAC countries unless both area-wide and targeted vector control approaches are adopted. The current evidence and the results from proposed transdisciplinary research on dengue within different ecosystems will help guide the development of new vector control strategies and foster a better understanding of climate change impacts on vector-borne disease transmission.

  4. Spatial Orientation and Balance Control Changes Induced by Altered Gravito-Inertial Force Vectors

    NASA Technical Reports Server (NTRS)

    Kaufman, Galen D.; Wood, Scott J.; Gianna, Claire C.; Black, F. Owen; Paloski, William H.; Dawson, David L. (Technical Monitor)

    1999-01-01

    Seventeen healthy and eight vestibular deficient subjects were exposed to an interaural centripetal acceleration of 1 G (resultant 45 deg roll tilt of 1.4 G) on a 0.8 meter radius centrifuge for a period of 90 minutes in the dark. The subjects sat with head fixed upright, except every 4 of 10 minutes when instructed to rotate their head so that their nose and eyes pointed towards a visual point switched on every 3 to 5 seconds at random places (within +/- 30 deg) in the Earth horizontal plane. Motion sickness caused some subjects to limit their head movements during significant portions of the 90 minute period, and led three normal subjects to stop the test earlier. Eye movements, including directed saccades for subjective Earth- and head-referenced planes, were recorded before, during, and immediately after centrifugation using electro-oculography. Postural stability measurements were made before and within ten minutes after centrifugation. In normal subjects, postural sway and multisegment body kinematics were gathered during an eyes-closed head movement cadence (sway-referenced support platform), and in response to translational/rotational platform perturbations. A significant increase in postural sway, segmental motion amplitude and hip frequency was observed after centrifugation. This effect was short-lived, with a recovery time of several postural test trials. There were also asymmetries in the direction of post-centrifugation center of sway and head tilt which depended on the subject's orientation during the centrifugation adaptation period (left ear or right ear out). To delineate the effect of the magnitude of the gravito-inertial vector versus its direction during the adaptive centrifugation period, we tilted eight normal subjects in the roll axis at a 45 deg angle in the dark for 90 minutes without rotational motion. Their postural responses did not change following the period of tilt. Based on verbal reports, normal subjects overestimated roll

  5. Responses of Wind Erosion to Climate-Induced Vegetation Changes on the Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Munson, S. M.; Belnap, J.; Okin, G. S.

    2012-12-01

    Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 years of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.; Perennial grasses and all perennial vegetation canopy cover (top panel) and modeled aeolian sediment flux (bottom panel) at five wind speeds (15.0, 17.5, 20.0, 22.5, and 25.0 ms-1) in relationship to mean annual temperature in the previous year in perennial grasslands across the Colorado Plateau, USA.

  6. Changing patterns of West Nile virus transmission: altered vector competence and host susceptibility

    PubMed Central

    Brault, Aaron C.

    2009-01-01

    West Nile virus (WNV) is a flavivirus (Flaviviridae) transmitted between Culex spp. mosquitoes and avian hosts. The virus has dramatically expanded its geographic range in the past ten years. Increases in global commerce, climate change, ecological factors and the emergence of novel viral genotypes likely play significant roles in the emergence of this virus; however, the exact mechanism and relative importance of each is uncertain. Previously WNV was primarily associated with febrile illness of children in endemic areas, but it was identified as a cause of neurological disease in humans in 1994. This modulation in disease presentation could be the result of the emergence of a more virulent genotype as well as the progression of the virus into areas in which the age structure of immunologically naïve individuals makes them more susceptible to severe neurological disease. Since its introduction to North America in 1999, a novel WNV genotype has been identified that has been demonstrated to disseminate more rapidly and with greater efficiency at elevated temperatures than the originally introduced strain, indicating the potential importance of temperature as a selective criteria for the emergence of WNV genotypes with increased vectorial capacity. Even prior to the North American introduction, a mutation associated with increased replication in avian hosts, identified to be under adaptive evolutionary pressure, has been identified, indicating that adaptation for increased replication within vertebrate hosts could play a role in increased transmission efficiency. Although stable in its evolutionary structure, WNV has demonstrated the capacity for rapidly adapting to both vertebrate hosts and invertebrate vectors and will likely continue to exploit novel ecological niches as it adapts to novel transmission foci. PMID:19406093

  7. Explaining technological change of wind power in China and the United States: Roles of energy policies, technological learning, and collaboration

    NASA Astrophysics Data System (ADS)

    Tang, Tian

    The following dissertation explains how technological change of wind power, in terms of cost reduction and performance improvement, is achieved in China and the US through energy policies, technological learning, and collaboration. The objective of this dissertation is to understand how energy policies affect key actors in the power sector to promote renewable energy and achieve cost reductions for climate change mitigation in different institutional arrangements. The dissertation consists of three essays. The first essay examines the learning processes and technological change of wind power in China. I integrate collaboration and technological learning theories to model how wind technologies are acquired and diffused among various wind project participants in China through the Clean Development Mechanism (CDM)--an international carbon trade program, and empirically test whether different learning channels lead to cost reduction of wind power. Using pooled cross-sectional data of Chinese CDM wind projects and spatial econometric models, I find that a wind project developer's previous experience (learning-by-doing) and industrywide wind project experience (spillover effect) significantly reduce the costs of wind power. The spillover effect provides justification for subsidizing users of wind technologies so as to offset wind farm investors' incentive to free-ride on knowledge spillovers from other wind energy investors. The CDM has played such a role in China. Most importantly, this essay provides the first empirical evidence of "learning-by-interacting": CDM also drives wind power cost reduction and performance improvement by facilitating technology transfer through collaboration between foreign turbine manufacturers and local wind farm developers. The second essay extends this learning framework to the US wind power sector, where I examine how state energy policies, restructuring of the electricity market, and learning among actors in wind industry lead to

  8. Electrostatic Solitary Waves in the Solar Wind: Evidence for Instability at Solar Wind Current Sheets

    NASA Technical Reports Server (NTRS)

    Malaspina, David M.; Newman, David L.; Wilson, Lynn Bruce; Goetz, Keith; Kellogg, Paul J.; Kerstin, Kris

    2013-01-01

    A strong spatial association between bipolar electrostatic solitary waves (ESWs) and magnetic current sheets (CSs) in the solar wind is reported here for the first time. This association requires that the plasma instabilities (e.g., Buneman, electron two stream) which generate ESWs are preferentially localized to solar wind CSs. Distributions of CS properties (including shear angle, thickness, solar wind speed, and vector magnetic field change) are examined for differences between CSs associated with ESWs and randomly chosen CSs. Possible mechanisms for producing ESW-generating instabilities at solar wind CSs are considered, including magnetic reconnection.

  9. Mars Pathfinder Landing Site: Evidence for a Change in Wind Regime and Climate from Lander and Orbiter Data

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Kraft, M. D.; Kuzmin, R. O.; Bridges, N. T.

    1999-01-01

    Surface features related to the wind are observed in data from the Mars Pathfinder lander and from orbit by the Viking Orbiter and Mars Global Surveyor missions. Features seen from the surface include wind tails associated with small rocks, barchanoid duneforms, ripplelike patterns, and ventifact flutes cut into some rocks. Features seen from orbit include wind tails associated with impact craters, ridges inferred to be duneforms, and modified crater rims interpreted to have been eroded and mantled by windblown material. The orientations of these features show two prevailing directions, one inferred to represent winds from the northeast which is consistent with strongest winds predicted by a general circulation model to occur during the Martian northern winter under current conditions, and a second wind pattern oriented approx. 90 degrees to the first. This latter wind could be from the W-NW or from the E-SE and was responsible for cutting the ventifacts and modifying the crater rims. The two wind regimes could reflect a change in climate related to Mars' obliquity or some other, unknown factor. Regardless of the cause, the MPF area has been subjected to a complex pattern of winds and supply of small particles, in which the original surface formed by sedimentary processes from Tiu and Ares Vallis events has been modified by repeated burial and exhumation.

  10. Projected changes in prevailing winds for transatlantic migratory birds under global warming.

    PubMed

    La Sorte, Frank A; Fink, Daniel

    2017-03-01

    A number of terrestrial bird species that breed in North America cross the Atlantic Ocean during autumn migration when travelling to their non-breeding grounds in the Caribbean or South America. When conducting oceanic crossings, migratory birds tend to associate with mild or supportive winds, whose speed and direction may change under global warming. The implications of these changes for transoceanic migratory bird populations have not been addressed. We used occurrence information from eBird (1950-2015) to estimate the geographical location of population centres at a daily temporal resolution across the annual cycle for 10 transatlantic migratory bird species. We used this information to estimate the location and timing of autumn migration within the transatlantic flyway. We estimated how prevailing winds are projected to change within the transatlantic flyway during this time using daily wind speed anomalies (1996-2005 and 2091-2100) from 29 Atmosphere-Ocean General Circulation Models implemented under CMIP5. Autumn transatlantic migrants have the potential to encounter strong westerly crosswinds early in their transatlantic journey at intermediate and especially high migration altitudes, strong headwinds at low and intermediate migration altitudes within the Caribbean that increase in strength as the season progresses, and weak tailwinds at intermediate and high migration altitudes east of the Caribbean. The CMIP5 simulations suggest that, during this century, the likelihood of autumn transatlantic migrants encountering strong westerly crosswinds will diminish. As global warming progresses, the need for species to compensate or drift under the influence of strong westerly crosswinds during the initial phase of their autumn transatlantic journey may be diminished. Existing strategies that promote headwind avoidance and tailwind assistance will likely remain valid. Thus, climate change may reduce time and energy requirements and the chance of mortality or

  11. Climate change could threaten blood supply by altering the distribution of vector-borne disease: an Australian case-study

    PubMed Central

    Bambrick, Hilary J.; Woodruff, Rosalie E.; Hanigan, Ivan C.

    2009-01-01

    Background Climate change is expected to promote more intense and prolonged outbreaks of vector-borne disease, and alter the geographic boundaries of transmission. This has implications for the safety and supply of fresh blood products around the world. In Australia, a recent outbreak of dengue fever caused a prolonged regional shortage in the supply of fresh blood products. Objective To highlight the potential for climate change to affect the safety and supply of blood globally through its impact on vector-borne disease, using the example of dengue in Australia as a case-study. Design We modelled geographic regions in Australia suitable for dengue transmission over the coming century under four climate change scenarios, estimated changes to the population at risk and effect on blood supply. Results Geographic regions with climates that are favourable to dengue transmission could expand to include large population centres in a number of currently dengue-free regions in Australia and reduce blood supply across several states. Conclusion Unless there is strong intergovernmental action on greenhouse gas reduction, there could be an eight-fold increase in the number of people living in dengue prone regions in Australia by the end of the century. Similar impacts will be experienced elsewhere and for other vector-borne diseases, with regions currently on the margins of transmission zones most affected. Globally, climate change is likely to compound existing problems of blood safety and supply in already endemic areas and cause future shortages in fresh blood products through its impact on transmission of vector-borne disease. PMID:20052315

  12. Predicted altitudinal shifts and reduced spatial distribution of Leishmania infantum vector species under climate change scenarios in Colombia.

    PubMed

    González, Camila; Paz, Andrea; Ferro, Cristina

    2014-01-01

    Visceral leishmaniasis (VL) is caused by the trypanosomatid parasite Leishmania infantum (=Leishmania chagasi), and is epidemiologically relevant due to its wide geographic distribution, the number of annual cases reported and the increase in its co-infection with HIV. Two vector species have been incriminated in the Americas: Lutzomyia longipalpis and Lutzomyia evansi. In Colombia, L. longipalpis is distributed along the Magdalena River Valley while L. evansi is only found in the northern part of the Country. Regarding the epidemiology of the disease, in Colombia the incidence of VL has decreased over the last few years without any intervention being implemented. Additionally, changes in transmission cycles have been reported with urban transmission occurring in the Caribbean Coast. In Europe and North America climate change seems to be driving a latitudinal shift of leishmaniasis transmission. Here, we explored the spatial distribution of the two known vector species of L. infantum in Colombia and projected its future distribution into climate change scenarios to establish the expansion potential of the disease. An updated database including L. longipalpis and L. evansi collection records from Colombia was compiled. Ecological niche models were performed for each species using the Maxent software and 13 Worldclim bioclimatic coverages. Projections were made for the pessimistic CSIRO A2 scenario, which predicts the higher increase in temperature due to non-emission reduction, and the optimistic Hadley B2 Scenario predicting the minimum increase in temperature. The database contained 23 records for L. evansi and 39 records for L. longipalpis, distributed along the Magdalena River Valley and the Caribbean Coast, where the potential distribution areas of both species were also predicted by Maxent. Climate change projections showed a general overall reduction in the spatial distribution of the two vector species, promoting a shift in altitudinal distribution for L

  13. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission.

    PubMed

    Parham, Paul E; Waldock, Joanna; Christophides, George K; Hemming, Deborah; Agusto, Folashade; Evans, Katherine J; Fefferman, Nina; Gaff, Holly; Gumel, Abba; LaDeau, Shannon; Lenhart, Suzanne; Mickens, Ronald E; Naumova, Elena N; Ostfeld, Richard S; Ready, Paul D; Thomas, Matthew B; Velasco-Hernandez, Jorge; Michael, Edwin

    2015-04-05

    Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10-15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems.

  14. An assessment of wind energy potential in Iberia under climate change

    NASA Astrophysics Data System (ADS)

    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 (<15% of mean output), but exacerbated in winter (40%). Climate change projections show significant decreases over most of Iberia (<2 MWh day-1). The strong enhancement of autumn potentials in Southern Andalucía is noteworthy (>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).

  15. Climate change impacts on the power generation potential of a European mid-century wind farms scenario

    NASA Astrophysics Data System (ADS)

    Tobin, Isabelle; Jerez, Sonia; Vautard, Robert; Thais, Françoise; van Meijgaard, Erik; Prein, Andreas; Déqué, Michel; Kotlarski, Sven; Fox Maule, Cathrine; Nikulin, Grigory; Noël, Thomas; Teichmann, Claas

    2016-03-01

    Wind energy resource is subject to changes in climate. To investigate the impacts of climate change on future European wind power generation potential, we analyze a multi-model ensemble of the most recent EURO-CORDEX regional climate simulations at the 12 km grid resolution. We developed a mid-century wind power plant scenario to focus the impact assessment on relevant locations for future wind power industry. We found that, under two greenhouse gas concentration scenarios, changes in the annual energy yield of the future European wind farms fleet as a whole will remain within ±5% across the 21st century. At country to local scales, wind farm yields will undergo changes up to 15% in magnitude, according to the large majority of models, but smaller than 5% in magnitude for most regions and models. The southern fleets such as the Iberian and Italian fleets are likely to be the most affected. With regard to variability, changes are essentially small or poorly significant from subdaily to interannual time scales.

  16. Wind Disturbance Produced Changes in Tree Species Assemblage in the Peruvian Amazon

    NASA Astrophysics Data System (ADS)

    Rifai, S. W.; Chambers, J. Q.; Negron Juarez, R. I.; Ramirez, F.; Tello, R.; Alegria Muñoz, W.

    2010-12-01

    Wind disturbance has been a frequently overlooked abiotic cause of mass tree mortality in the Amazon basin. In the Peruvian Amazon these wind disturbances are produced by meteorological events such as convective systems. Downbursts for example produce short term descendent wind speeds that can be in excess of 30 m s-1. These are capable of producing tree blowdowns which have been reported to be as large as 33 km2 in the Amazon basin. We used the chronosequence of Landsat Satellite imagery to find and locate where these blowdowns have occurred in the Loreto region of the Peruvian Amazon. Spectral Mixture Analysis was used to estimate the proportion landcover of green vegetation, non-photosynthetic vegetation (NPV), soil and shade in each pixel. The change in NPV was calculated by subtracting the NPV signal in the Landsat image prior to the blowdown occurrence, from the image following the disturbance. Our prior research has established a linear relationship between tree mortality and change in NPV. It is hypothesized that these mass tree mortality events result in changes in the tree species assemblage of affected forests. Here we present preliminary tree species assemblage data from two sites in the Peruvian Amazon near Iquitos, Peru. The site (ALP) at the Allpahuayo Mishana reserve (3.945 S, 73.455 W) is 30 km south of Iquitos, Peru, and hosts the remnants of a 50 ha blowdown that occurred in either 1992 or 1993. Another site (NAPO) on the Napo river about 60 km north of Iquitos, is the location of an approximately 300 ha blowdown that occurred in 1998. At each site, a 3000 m x 10 m transect encompassing non disturbed and disturbed areas was installed, and trees greater than 10 cm diameter at breast height were measured for diameter, height and were identified to the species. Stem density of trees with diameter at breast height > 10 cm, and tree height appear to be similar both inside and outside the blowdown affected areas of the forests at both sites. At the ALP

  17. Numerical modeling on air quality in an urban environment with changes of the aspect ratio and wind direction.

    PubMed

    Yassin, Mohamed F

    2013-06-01

    Due to heavy traffic emissions within an urban environment, air quality during the last decade becomes worse year by year and hazard to public health. In the present work, numerical modeling of flow and dispersion of gaseous emissions from vehicle exhaust in a street canyon were investigated under changes of the aspect ratio and wind direction. The three-dimensional flow and dispersion of gaseous pollutants were modeled using a computational fluid dynamics (CFD) model which was numerically solved using Reynolds-averaged Navier-Stokes (RANS) equations. The diffusion flow field in the atmospheric boundary layer within the street canyon was studied for different aspect ratios (W/H=1/2, 3/4, and 1) and wind directions (θ=90°, 112.5°, 135°, and 157.5°). The numerical models were validated against wind tunnel results to optimize the turbulence model. The numerical results agreed well with the wind tunnel results. The simulation demonstrated that the minimum concentration at the human respiration height within the street canyon was on the windward side for aspect ratios W/H=1/2 and 1 and wind directions θ=112.5°, 135°, and 157.5°. The pollutant concentration level decreases as the wind direction and aspect ratio increase. The wind velocity and turbulence intensity increase as the aspect ratio and wind direction increase.

  18. Removing Ambiguities In Remotely Sensed Winds

    NASA Technical Reports Server (NTRS)

    Shaffer, Scott J.; Dunbar, Roy S.; Hsiao, Shuchi V.; Long, David G.

    1991-01-01

    Algorithm removes ambiguities in choices of candidate ocean-surface wind vectors estimated from measurements of radar backscatter from ocean waves. Increases accuracies of estimates of winds without requiring new instrumentation. Incorporates vector-median filtering function.

  19. Assessment of future scenarios for wind erosion sensitivity changes based on ALADIN and REMO regional climate model simulation data

    NASA Astrophysics Data System (ADS)

    Mezősi, Gábor; Blanka, Viktória; Bata, Teodóra; Ladányi, Zsuzsanna; Kemény, Gábor; Meyer, Burghard C.

    2016-07-01

    The changes in rate and pattern of wind erosion sensitivity due to climate change were investigated for 2021-2050 and 2071-2100 compared to the reference period (1961-1990) in Hungary. The sensitivities of the main influencing factors (soil texture, vegetation cover and climate factor) were evaluated by fuzzy method and a combined wind erosion sensitivity map was compiled. The climate factor, as the driving factor of the changes, was assessed based on observed data for the reference period, while REMO and ALADIN regional climate model simulation data for the future periods. The changes in wind erosion sensitivity were evaluated on potentially affected agricultural land use types, and hot spot areas were allocated. Based on the results, 5-6% of the total agricultural areas were high sensitive areas in the reference period. In the 21st century slight or moderate changes of wind erosion sensitivity can be expected, and mostly `pastures', `complex cultivation patterns', and `land principally occupied by agriculture with significant areas of natural vegetation' are affected. The applied combination of multi-indicator approach and fuzzy analysis provides novelty in the field of land sensitivity assessment. The method is suitable for regional scale analysis of wind erosion sensitivity changes and supports regional planning by allocating priority areas where changes in agro-technics or land use have to be considered.

  20. Climate Change, Offshore Wind Power, and the Coastal Zone Management Act

    DTIC Science & Technology

    2008-09-01

    have begun to plan and develop coastal and offshore wind energy farms,9 the largest and best-known being Cape Wind Associates’ proposal for a 130...is produced. Offshore wind energy projects can conversely take advantage of the relatively consistent nature of coastal winds, caused by the...coastal zone management programs. The CZMA provides for two types of federal consistency, the second of which is directly relevant to offshore wind energy development

  1. Magnetopause Boundary Standoff Position Changes and Its Time-Dependent Response to Solar Wind Conditions: Models and Observations

    NASA Astrophysics Data System (ADS)

    Collado-Vega, Y. M.; Sibeck, D. G.; Rastaetter, L.

    2015-12-01

    The Earth's magnetopause is the boundary that separates the solar wind and the Earth's magnetosphere. Its location as a function of solar wind conditions has been estimated via theory, simulation, and empirical models. This presentation compares magnetopause standoff locations determined by all these methods. We use the Run-On-Request capabilities available from the Community Coordinated Modeling Center (CCMC) at NASA Goddard Space Flight Center, specifically the BATS-R-US, OpenGGCM, LFM and GUMICS global physics-based MHD models. The simulated magnetopause standoff positions and response time to the solar wind changes will then be compared with the results obtained using empirical models (e.g. Shue et al. 1998), and to individual THEMIS, Cluster and the Geotail magnetopause crossing observations. We also inspect times of extreme solar wind conditions when magnetopause crossings have been observed by the GOES satellites. Rigorous analysis/comparison of observations with models is critical in determining the performance of the models used to capture magnetospheric dynamics. We will also identify which types of solar wind conditions lead to significant differences between the models. Preliminary results show that there can be significant discrepancies between magnetopause locations predicted by different global MHD models. The discrepancies are seen, for example, during increases in solar wind dynamic pressure and sharp changes in the IMF Bz component. Preliminary results also indicate that during nominal background solar wind conditions models do agree with the observed magnetopause locations.

  2. Spatial orientation and balance control changes induced by altered gravitoinertial force vectors

    NASA Technical Reports Server (NTRS)

    Kaufman, G. D.; Wood, S. J.; Gianna, C. C.; Black, F. O.; Paloski, W. H.

    2001-01-01

    were short-lived, however, with a recovery time of several postural test trials (minutes). There were also asymmetries in the direction of postcentrifugation COP and head tilt which depended on the subject's orientation during the centrifugation adaptation period (left ear or right ear out). The amount of total head movements during centrifugation correlated poorly or inversely with postcentrifugation postural stability, and the most unstable subject made no head movements. There was no decrease in postural stability after static tilt, although these subjects also reported a perceived tilt briefly after return to upright, and they also had COP asymmetries. Abnormal subjects underestimated roll-tilt during centrifugation, and their directed saccades revealed permanent spatial distortions. Bilateral abnormal subjects started out with poor postural control, but showed no postural decrements after centrifugation, while unilateral abnormal subjects had varying degrees of postural decrement, both in their everyday function and as a result of experiencing the centrifugation. In addition, three unilateral, abnormal subjects, who rode twice in opposite orientations, revealed a consistent orthogonal pattern of COP offsets after centrifugation. These results suggest that both orientation and magnitude of the gravitoinertial vector are used by the central nervous system for calibration of multiple orientation systems. A change in the background gravitoinertial force (otolith input) can rapidly initiate postural and perceptual adaptation in several sensorimotor systems, independent of a structured visual surround.

  3. Wind Tunnel Test of an RPV with Shape-Change Control Effector and Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Cabell, Randolph H.; Sloan, Adam R.; Barnwell, William G.; Lion, S. Todd; Hautamaki, Bret A.

    2004-01-01

    A variety of novel control effector concepts have recently emerged that may enable new approaches to flight control. In particular, the potential exists to shift the composition of the typical aircraft control effector suite from a small number of high authority, specialized devices (rudder, aileron, elevator, flaps), toward larger numbers of smaller, less specialized, distributed device arrays. The concept envisions effector and sensor networks composed of relatively small high-bandwidth devices able to simultaneously perform a variety of control functions using feedback from disparate data sources. To investigate this concept, a remotely piloted flight vehicle has been equipped with an array of 24 trailing edge shape-change effectors and associated pressure measurements. The vehicle, called the Multifunctional Effector and Sensor Array (MESA) testbed, was recently tested in NASA Langley's 12-ft Low Speed wind tunnel to characterize its stability properties, control authorities, and distributed pressure sensitivities for use in a dynamic simulation prior to flight testing. Another objective was to implement and evaluate a scheme for actively controlling the spanwise pressure distribution using the shape-change array. This report describes the MESA testbed, design of the pressure distribution controller, and results of the wind tunnel test.

  4. Cardiac vectors in the healthy human fetus: developmental changes assessed by magnetocardiography and realistic approximations of the volume conductor

    PubMed Central

    Tao, R; Popescu, EA; Drake, WB; Popescu, M

    2014-01-01

    This study sought to characterize the developmental changes of three measures used to describe the morphology of the fetal cardiac vector: QRS peak-amplitude, QRS duration and QRS time-amplitude integral. To achieve this objective, we rely on a recently developed methodology for fetal cardiac vector estimation, using multichannel fetal magnetocardiographic (fMCG) recordings and realistic approximations of the volume conductors obtained from free-hand ultrasound imaging. Fetal magnetocardiographic recordings and 3D ultrasound images were obtained from 23 healthy, uncomplicated pregnancies for a total of 77 recordings performed at gestational ages between 22 weeks and 37 weeks. We report the developmental changes of the cardiac vector parameters with respect to gestational age and estimated fetal weight, as well as their dependence on the estimated ventricular mass derived from cardiac dimensions measured with M-mode ultrasound. The normative values can be used along with the cardiac time intervals reported by previous fMCG studies to assist future clinical studies investigating conditions that affect fetal cardiac function. PMID:23604003

  5. Cardiac vectors in the healthy human fetus: developmental changes assessed by magnetocardiography and realistic approximations of the volume conductor.

    PubMed

    Tao, R; Popescu, E A; Drake, W B; Popescu, M

    2013-05-01

    This study sought to characterize the developmental changes of three measures used to describe the morphology of the fetal cardiac vector: QRS peak-amplitude, QRS duration and QRS time-amplitude integral. To achieve this objective, we rely on a recently developed methodology for fetal cardiac vector estimation, using multichannel fetal magnetocardiographic (fMCG) recordings and realistic approximations of the volume conductors obtained from free-hand ultrasound imaging. fMCG recordings and 3D ultrasound images were obtained from 23 healthy, uncomplicated pregnancies for a total of 77 recordings performed at gestational ages between 22 and 37 weeks. We report the developmental changes of the cardiac vector parameters with respect to gestational age and estimated fetal weight, as well as their dependence on the estimated ventricular mass derived from cardiac dimensions measured with M-mode ultrasound. The normative values can be used along with the cardiac time intervals reported by previous fMCG studies to assist future clinical studies investigating conditions that affect fetal cardiac function.

  6. Impacts of Climate Change on Vector Borne Diseases in the Mediterranean Basin — Implications for Preparedness and Adaptation Policy

    PubMed Central

    Negev, Maya; Paz, Shlomit; Clermont, Alexandra; Pri-Or, Noemie Groag; Shalom, Uri; Yeger, Tamar; Green, Manfred S.

    2015-01-01

    The Mediterranean region is vulnerable to climatic changes. A warming trend exists in the basin with changes in rainfall patterns. It is expected that vector-borne diseases (VBD) in the region will be influenced by climate change since weather conditions influence their emergence. For some diseases (i.e., West Nile virus) the linkage between emergence andclimate change was recently proved; for others (such as dengue) the risk for local transmission is real. Consequently, adaptation and preparation for changing patterns of VBD distribution is crucial in the Mediterranean basin. We analyzed six representative Mediterranean countries and found that they have started to prepare for this threat, but the preparation levels among them differ, and policy mechanisms are limited and basic. Furthermore, cross-border cooperation is not stable and depends on international frameworks. The Mediterranean countries should improve their adaptation plans, and develop more cross-sectoral, multidisciplinary and participatory approaches. In addition, based on experience from existing local networks in advancing national legislation and trans-border cooperation, we outline recommendations for a regional cooperation framework. We suggest that a stable and neutral framework is required, and that it should address the characteristics and needs of African, Asian and European countries around the Mediterranean in order to ensure participation. Such a regional framework is essential to reduce the risk of VBD transmission, since the vectors of infectious diseases know no political borders. PMID:26084000

  7. Impacts of Climate Change on Vector Borne Diseases in the Mediterranean Basin - Implications for Preparedness and Adaptation Policy.

    PubMed

    Negev, Maya; Paz, Shlomit; Clermont, Alexandra; Pri-Or, Noemie Groag; Shalom, Uri; Yeger, Tamar; Green, Manfred S

    2015-06-15

    The Mediterranean region is vulnerable to climatic changes. A warming trend exists in the basin with changes in rainfall patterns. It is expected that vector-borne diseases (VBD) in the region will be influenced by climate change since weather conditions influence their emergence. For some diseases (i.e., West Nile virus) the linkage between emergence andclimate change was recently proved; for others (such as dengue) the risk for local transmission is real. Consequently, adaptation and preparation for changing patterns of VBD distribution is crucial in the Mediterranean basin. We analyzed six representative Mediterranean countries and found that they have started to prepare for this threat, but the preparation levels among them differ, and policy mechanisms are limited and basic. Furthermore, cross-border cooperation is not stable and depends on international frameworks. The Mediterranean countries should improve their adaptation plans, and develop more cross-sectoral, multidisciplinary and participatory approaches. In addition, based on experience from existing local networks in advancing national legislation and trans-border cooperation, we outline recommendations for a regional cooperation framework. We suggest that a stable and neutral framework is required, and that it should address the characteristics and needs of African, Asian and European countries around the Mediterranean in order to ensure participation. Such a regional framework is essential to reduce the risk of VBD transmission, since the vectors of infectious diseases know no political borders.

  8. Wind Characterization for the Assessment of Collision Risk During Flight Level Changes

    NASA Technical Reports Server (NTRS)

    Carreno, Victor; Chartrand, Ryan

    2009-01-01

    A model of vertical wind gradient is presented based on National Oceanic and Atmospheric Administration (NOAA) wind data. The objective is to have an accurate representation of wind to be used in Collision Risk Models (CRM) of aircraft procedures. Depending on how an aircraft procedure is defined, wind and the different characteristics of the wind will have a more severe or less severe impact on distances between aircraft. For the In-Trail Procedure, the non-linearity of the vertical wind gradient has the greatest impact on longitudinal distance. The analysis in this paper extracts standard deviation, mean, maximum, and linearity characteristics from the NOAA data.

  9. Impact of WRF Physics and Grid Resolution on Low-level Wind Prediction: Towards the Assessment of Climate Change Impact on Future Wind Power

    SciTech Connect

    Chin, H S; Glascoe, L; Lundquist, J; Wharton, S

    2010-02-24

    The Weather Research and Forecast (WRF) model is used in short-range simulations to explore the sensitivity of model physics and horizontal grid resolution. We choose five events with the clear-sky conditions to study the impact of different planetary boundary layer (PBL), surface and soil-layer physics on low-level wind forecast for two wind farms; one in California (CA) and the other in Texas (TX). Short-range simulations are validated with field measurements. Results indicate that the forecast error of the CA case decreases with increasing grid resolution due to the improved representation of valley winds. Besides, the model physics configuration has a significant impact on the forecast error at this location. In contrast, the forecast error of the TX case exhibits little dependence on grid resolution and is relatively independent of physics configuration. Therefore, the occurrence frequency of lowest root mean square errors (RMSEs) at this location is used to determine an optimal model configuration for subsequent decade-scale regional climate model (RCM) simulations. In this study, we perform two sets of 20-year RCM simulations using the data from the NCAR Global Climate Model (GCM) simulations; one set models the present climate and the other simulates the future climate. These RCM simulations will be used to assess the impact of climate change on future wind energy.

  10. Wind power: Addressing wildlife impacts, assessing effects on tourism, and examining the link between climate change perceptions and support

    NASA Astrophysics Data System (ADS)

    Lilley, Meredith Blaydes

    As the world's most rapidly growing source of energy, wind power has vast potential for mitigating climate change and advancing global environmental sustainability. Yet, the challenges facing wind energy remain both complex and substantial. Two such challenges are: 1) wildlife impacts; and 2) perceived negative effects on tourism. This dissertation examines these challenges in a multi-paper format, and also investigates the role that climate change perceptions play in garnering public support for wind power. The first paper assesses optimal approaches for addressing wind power's wildlife impacts. Comparative analysis reveals that avian mortality from turbines ranks far behind avian mortality from a number of other anthropogenic sources. Additionally, although bats have recently emerged as more vulnerable to wind turbines than birds, they are generally less federally protected. The Migratory Bird Treaty Act (MBTA) protects over 800 bird species, regardless of their threatened or endangered status. Moreover, it criminalizes the incidental take of birds without a permit and simultaneously grants no permits for such incidental take, thereby creating a legal conundrum for the wind industry. An examination of the legislative and case history of the MBTA, however, reveals that wind operators are not likely to be prosecuted for incidental take if they cooperate with the U.S. Fish & Wildlife Service (FWS) and take reasonable steps to reduce siting and operational impacts. Furthermore, this study's analysis reveals modest wildlife impacts from wind power, in comparison with numerous other energy sources. Scientific-research, legal, and policy recommendations are provided to update the present legal and regulatory regime under the MBTA and to minimize avian and bat impacts. For instance, FWS should: establish comprehensive federal guidelines for wind facility siting, permitting, monitoring, and mitigation; and promulgate regulations under the MBTA for the issuance of

  11. Could a change in magnetic field geometry cause the break in the wind-activity relation?

    NASA Astrophysics Data System (ADS)

    Vidotto, A. A.; Donati, J.-F.; Jardine, M.; See, V.; Petit, P.; Boisse, I.; Boro Saikia, S.; Hébrard, E.; Jeffers, S. V.; Marsden, S. C.; Morin, J.

    2016-01-01

    Wood et al. suggested that mass-loss rate is a function of X-ray flux (dot{M}∝ F_x^{1.34}) for dwarf stars with Fx ≲ Fx,6 ≡ 106 erg cm-2 s-1. However, more active stars do not obey this relation. These authors suggested that the break at Fx,6 could be caused by significant changes in magnetic field topology that would inhibit stellar wind generation. Here, we investigate this hypothesis by analysing the stars in Wood et al. sample that had their surface magnetic fields reconstructed through Zeeman-Doppler Imaging (ZDI). Although the solar-like outliers in the dot{M} - Fx relation have higher fractional toroidal magnetic energy, we do not find evidence of a sharp transition in magnetic topology at Fx,6. To confirm this, further wind measurements and ZDI observations at both sides of the break are required. As active stars can jump between states with highly toroidal to highly poloidal fields, we expect significant scatter in magnetic field topology to exist for stars with Fx ≳ Fx,6. This strengthens the importance of multi-epoch ZDI observations. Finally, we show that there is a correlation between Fx and magnetic energy, which implies that dot{M} - magnetic energy relation has the same qualitative behaviour as the original dot{M} - Fx relation. No break is seen in any of the Fx - magnetic energy relations.

  12. Global climate change and its potential impact on disease transmission by salinity-tolerant mosquito vectors in coastal zones.

    PubMed

    Ramasamy, Ranjan; Surendran, Sinnathamby Noble

    2012-01-01

    Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis, and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall, and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with <0.5 ppt or parts per thousand, 0.5-30 ppt and >30 ppt salt are termed fresh, brackish, and saline respectively) will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross-McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase the densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti, and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for increased

  13. Global Climate Change and Its Potential Impact on Disease Transmission by Salinity-Tolerant Mosquito Vectors in Coastal Zones

    PubMed Central

    Ramasamy, Ranjan; Surendran, Sinnathamby Noble

    2012-01-01

    Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis, and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall, and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with <0.5 ppt or parts per thousand, 0.5–30 ppt and >30 ppt salt are termed fresh, brackish, and saline respectively) will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross–McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase the densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti, and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for

  14. Remote sensing of land use/cover changes and its effect on wind erosion potential in southern Iran

    PubMed Central

    Sameni, Abdolmajid; Fallah Shamsi, Seyed Rashid; Bartholomeus, Harm

    2016-01-01

    Wind erosion is a complex process influenced by different factors. Most of these factors are stable over time, but land use/cover and land management practices are changing gradually. Therefore, this research investigates the impact of changing land use/cover and land management on wind erosion potential in southern Iran. We used remote sensing data (Landsat ETM+ and Landsat 8 imagery of 2004 and 2013) for land use/cover mapping and employed the Iran Research Institute of Forest and Rangeland (IRIFR) method to estimate changes in wind erosion potential. For an optimal mapping, the performance of different classification algorithms and input layers was tested. The amount of changes in wind erosion and land use/cover were quantified using cross-tabulation between the two years. To discriminate land use/cover related to wind erosion, the best results were obtained by combining the original spectral bands with synthetic bands and using Maximum Likelihood classification algorithm (Kappa Coefficient of 0.8 and 0.9 for Landsat ETM+ and Landsat 8, respectively). The IRIFR modelling results indicate that the wind erosion potential has increased over the last decade. The areas with a very high sediment yield potential have increased, whereas the areas with a low, medium, and high sediment yield potential decreased. The area with a very low sediment yield potential have remained constant. When comparing the change in erosion potential with land use/cover change, it is evident that soil erosion potential has increased mostly in accordance with the increase of the area of agricultural practices. The conversion of rangeland to agricultural land was a major land-use change which lead to more agricultural practices and associated soil loss. Moreover, results indicate an increase in sandification in the study area which is also a clear evidence of increasing in soil erosion. PMID:27547511

  15. Remote sensing of land use/cover changes and its effect on wind erosion potential in southern Iran.

    PubMed

    Rezaei, Mahrooz; Sameni, Abdolmajid; Fallah Shamsi, Seyed Rashid; Bartholomeus, Harm

    2016-01-01

    Wind erosion is a complex process influenced by different factors. Most of these factors are stable over time, but land use/cover and land management practices are changing gradually. Therefore, this research investigates the impact of changing land use/cover and land management on wind erosion potential in southern Iran. We used remote sensing data (Landsat ETM+ and Landsat 8 imagery of 2004 and 2013) for land use/cover mapping and employed the Iran Research Institute of Forest and Rangeland (IRIFR) method to estimate changes in wind erosion potential. For an optimal mapping, the performance of different classification algorithms and input layers was tested. The amount of changes in wind erosion and land use/cover were quantified using cross-tabulation between the two years. To discriminate land use/cover related to wind erosion, the best results were obtained by combining the original spectral bands with synthetic bands and using Maximum Likelihood classification algorithm (Kappa Coefficient of 0.8 and 0.9 for Landsat ETM+ and Landsat 8, respectively). The IRIFR modelling results indicate that the wind erosion potential has increased over the last decade. The areas with a very high sediment yield potential have increased, whereas the areas with a low, medium, and high sediment yield potential decreased. The area with a very low sediment yield potential have remained constant. When comparing the change in erosion potential with land use/cover change, it is evident that soil erosion potential has increased mostly in accordance with the increase of the area of agricultural practices. The conversion of rangeland to agricultural land was a major land-use change which lead to more agricultural practices and associated soil loss. Moreover, results indicate an increase in sandification in the study area which is also a clear evidence of increasing in soil erosion.

  16. Changes in fluxes of heat, H2O, CO2 caused by a large wind farm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Crop Wind Energy Experiment (CWEX) provides a platform to investigate the effect of wind turbines and large wind farms on surface fluxes of momentum, heat, moisture and carbon dioxide (CO2). In 2010 and 2011, eddy covariance flux stations were installed between two lines of turbines at the south...

  17. Effects of Microclimate Condition Changes Due to Land Use and Land Cover Changes on the Survivorship of Malaria Vectors in China-Myanmar Border Region

    PubMed Central

    Zhong, Daibin; Wang, Xiaoming; Xu, Tielong; Zhou, Guofa; Wang, Ying; Lee, Ming-Chieh; Hartsel, Joshua A.; Cui, Liwang; Zheng, Bin; Yan, Guiyun

    2016-01-01

    In the past decade, developing countries have been experiencing rapid land use and land cover changes, including deforestation and cultivation of previously forested land. However, little is known about the impact of deforestation and land-use changes on the life history of malaria vectors and their effects on malaria transmission. This study examined the effects of deforestation and crop cultivation on the adult survivorship of major malaria mosquitoes, Anopheles sinensis and An. minimus in the China-Myanmar border region. We examined three conditions: indoor, forested, and banana plantation. Mean survival time of An. sinensis in banana plantation environment was significantly longer than those in forested environment, and mosquitoes exhibited the longest longevity in the indoor environment. This pattern held for both males and females, and also for An. minimus. To further test the effect of temperature on mosquito survival, we used two study sites with different elevation and ambient temperatures. Significantly higher survivorship of both species was found in sites with lower elevation and higher ambient temperature. Increased vector survival in the deforested area could have an important impact on malaria transmission in Southeast Asia. Understanding how deforestation impacts vector survivorship can help combat malaria transmission. PMID:27171475

  18. Effects of Microclimate Condition Changes Due to Land Use and Land Cover Changes on the Survivorship of Malaria Vectors in China-Myanmar Border Region.

    PubMed

    Zhong, Daibin; Wang, Xiaoming; Xu, Tielong; Zhou, Guofa; Wang, Ying; Lee, Ming-Chieh; Hartsel, Joshua A; Cui, Liwang; Zheng, Bin; Yan, Guiyun

    2016-01-01

    In the past decade, developing countries have been experiencing rapid land use and land cover changes, including deforestation and cultivation of previously forested land. However, little is known about the impact of deforestation and land-use changes on the life history of malaria vectors and their effects on malaria transmission. This study examined the effects of deforestation and crop cultivation on the adult survivorship of major malaria mosquitoes, Anopheles sinensis and An. minimus in the China-Myanmar border region. We examined three conditions: indoor, forested, and banana plantation. Mean survival time of An. sinensis in banana plantation environment was significantly longer than those in forested environment, and mosquitoes exhibited the longest longevity in the indoor environment. This pattern held for both males and females, and also for An. minimus. To further test the effect of temperature on mosquito survival, we used two study sites with different elevation and ambient temperatures. Significantly higher survivorship of both species was found in sites with lower elevation and higher ambient temperature. Increased vector survival in the deforested area could have an important impact on malaria transmission in Southeast Asia. Understanding how deforestation impacts vector survivorship can help combat malaria transmission.

  19. The national assessment of shoreline change: A GIS compilation of vector shorelines and associated shoreline change data for the New England and Mid-Atlantic Coasts

    USGS Publications Warehouse

    Himmelstoss, Emily A.; Kratzmann, Meredith G.; Hapke, Cheryl; Thieler, E. Robert; List, Jeffrey

    2010-01-01

    Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. The U.S. Geological Survey's National Assessment of Shoreline Change Project has compiled a comprehensive database of digital vector shorelines and shoreline-change rates for the New England and Mid-Atlantic Coasts. There is currently no widely accepted standard for analyzing shoreline change. Existing measurement and rate-calculation methods vary from study to study and preclude combining results into statewide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method that is consistent from coast to coast for measuring changes in shoreline position. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.

  20. Cellular automata for simulating land use changes based on support vector machines

    NASA Astrophysics Data System (ADS)

    Yang, Qingsheng; Li, Xia; Shi, Xun

    2008-06-01

    Cellular automata (CA) have been increasingly used to simulate urban sprawl and land use dynamics. A major issue in CA is defining appropriate transition rules based on training data. Linear boundaries have been widely used to define the rules. However, urban land use dynamics and many other geographical phenomena are highly complex and require nonlinear boundaries for the rules. In this study, we tested the support vector machines (SVM) as a method for constructing nonlinear transition rules for CA. SVM is good at dealing with nonlinear complex relationships. Its basic idea is to project input vectors to a higher dimensional Hilbert feature space, in which an optimal classifying hyperplane can be constructed through structural risk minimization and margin maximization. The optimal hyperplane is unique and its optimality is global. The proposed SVM-CA model was implemented using Visual Basic, ArcObjects®, and OSU-SVM. A case study simulating the urban development in the Shenzhen City, China demonstrates that the proposed model can achieve high accuracy and overcome some limitations of existing CA models in simulating complex urban systems.

  1. Incidence of Vector-borne Disease and Climate Change: A Study in Semi-arid Algeria

    NASA Astrophysics Data System (ADS)

    Blakey, T.; Bounoua, L.

    2012-12-01

    Leishmaniases are among the most important emerging and resurging vector-borne diseases, second only to malaria in terms of the number of affected people. Leishmaniases are endemic in 88 countries worldwide and threaten about 350 million people (WHO, 2007). Since the first reported case of zoonotic cutaneous leishmaniasis (ZCL) in Saida, Algeria in 1991, 1,275 cases have been recorded (Makhlouf & Houti, 2010) with the vast majority of study-area cases (99%) reported between the years of 2000 and 2009. An investigation of potential climatic indicators for the apparent shift in disease prevalence was conducted by comparing anomalies in the climate data specific to the local pathogen cycle. It was determined that long term climate trends have resulted in conditions that promote the prevalence of ZCL. Increased precipitation have resulted in greater vegetation and promoted host and vector population growth through a trophic cascade. Increased minimum temperatures have lengthened the annual duration of sandfly activity. Short term variations in maximum temperatures, however show a correlation with disease suppression in the subsequent years. These findings indicate a potential to forecast the risk of ZCL infection through models of the trophic cascade and sandfly population growth.

  2. Agents of change on Mars' northern dunes: CO2 ice and wind

    NASA Astrophysics Data System (ADS)

    Hansen, C. J.; Diniega, S.; Bridges, N.; Byrne, S.; Dundas, C.; McEwen, A.; Portyankina, G.

    2015-05-01

    Both wind and seasonal CO2 ice sculpt the dunes of Mars in today's climate. The High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter has returned extensive temporal coverage of changes on the north polar dunes for nearly four Mars years. The processes driving dune morphology changes such as the formation of new alcoves have been investigated. Considerable interannual variability has been observed. Most changes occur in the period of time when HiRISE cannot image: late summer and fall when light levels are too low to see subtle changes on the dunes and the polar hood obscures the surface, and winter when the cap is in polar night. This is consistent with seasonal control but does not allow us to directly differentiate between eolian processes vs. CO2 ice as the driving agent for alcove formation. Circumstantial evidence and observations of analog processes in the southern mid-latitudes however implicates processes associated with frost emplacement and removal.

  3. Efficacy of child abuse and neglect prevention messages in the Florida Winds of Change campaign.

    PubMed

    Evans, W Douglas; Falconer, Mary Kay; Khan, Munziba; Ferris, Christie

    2012-01-01

    Public awareness campaigns have been included in universal, communitywide, and programmatic approaches aimed at preventing child abuse and neglect. More evaluation of campaign effects is needed to identify their place on the continuum of evidence-based programs. This article reports on an efficacy study of the Florida Winds of Change campaign using a randomized experimental design. Investigators conducted an online survey of a web-based panel of Florida residents with children 18 years of age or younger living in the home. Six outcomes were measured at baseline and a 30-day follow-up. Three outcomes referred to knowledge of child development, child disciplinary techniques, and community resources for parents. Prevention attitudes or beliefs, motivation, and action were also assessed. Respondents were exposed to three public service announcements and a selection of parent resource material. Logistic regression models revealed that exposure to campaign messages was associated with significant increases in all but one of the campaign outcomes.

  4. Ground winds and winds aloft Edwards AFB, California

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.; Brown, S. C.

    1977-01-01

    Ground level runway wind statistics cover crosswind, tailwind, and headwind reversal percentage frequencies with respect to month and hour for the two major runways. Also presented are bivariate normal wind statistics for a 90 degree flight azimuth for altitudes 0 through 27 km. Wind probability distributions, synthetic vector wind profiles, and statistics for any rotation of axes are computed from five given parameters.

  5. Impact of climate change upon vector born diseases in Europe and Africa using ENSEMBLES Regional Climate Models

    NASA Astrophysics Data System (ADS)

    Caminade, Cyril; Morse, Andy

    2010-05-01

    Climate variability is an important component in determining the incidence of a number of diseases with significant human/animal health and socioeconomic impacts. The most important diseases affecting health are vector-borne, such as malaria, Rift Valley Fever and including those that are tick borne, with over 3 billion of the world population at risk. Malaria alone is responsible for at least one million deaths annually, with 80% of malaria deaths occurring in sub-Saharan Africa. The climate has a large impact upon the incidence of vector-borne diseases; directly via the development rates and survival of both the pathogen and the vector, and indirectly through changes in the environmental conditions. A large ensemble of regional climate model simulations has been produced within the ENSEMBLES project framework for both the European and African continent. This work will present recent progress in human and animal disease modelling, based on high resolution climate observations and regional climate simulations. Preliminary results will be given as an illustration, including the impact of climate change upon bluetongue (disease affecting the cattle) over Europe and upon malaria and Rift Valley Fever over Africa. Malaria scenarios based on RCM ensemble simulations have been produced for West Africa. These simulations have been carried out using the Liverpool Malaria Model. Future projections highlight that the malaria incidence decreases at the northern edge of the Sahel and that the epidemic belt is shifted southward in autumn. This could lead to significant public health problems in the future as the demography is expected to dramatically rise over Africa for the 21st century.

  6. Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model

    NASA Astrophysics Data System (ADS)

    Morin, Cory W.; Comrie, Andrew C.

    2010-09-01

    Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model ( P < 0.0001). Dry environments in southern California produce different mosquito population trends than moist locations in Florida. Florida and California mosquito populations are generally temperature-limited in winter. In California, locations are water-limited through much of the year. Using future climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions.

  7. Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model.

    PubMed

    Morin, Cory W; Comrie, Andrew C

    2010-09-01

    Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model (P < 0.0001). Dry environments in southern California produce different mosquito population trends than moist locations in Florida. Florida and California mosquito populations are generally temperature-limited in winter. In California, locations are water-limited through much of the year. Using future climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions.

  8. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission

    DOE PAGES

    Parham, Paul E.; Waldock, Joanna; Christophides, George K.; ...

    2015-02-16

    Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is due not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but, perhaps most crucially, the multitude of epidemiological, ecological, and socioeconomic factors that drive VBD transmission, and this complexity has generated considerable debate over the last 10-15 years. Inmore » this article, and Theme Issue, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions, and, crucially, offer some solutions for the field moving forwards. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems. This Theme Issue seeks to cover both, reflected in the breadth and depth of the topics and VBD-systems considered, itself strongly indicative of the challenging, but necessary, multidisciplinary nature of this research field.« less

  9. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission

    SciTech Connect

    Parham, Paul E.; Waldock, Joanna; Christophides, George K.; Hemming, Deborah; Agusto, Folashade; Evans, Katherine J.; Fefferman, Nina; Gaff, Holly; Gumel, Abba; LaDeau, Shannon; Lenhart, Suzanne; Mickens, Ronald E.; Naumova, Elena N.; Ostfeld, Richard S.; Ready, Paul D.; Thomas, Matthew B.; Velasco-Hernandez, Jorge; Michael, Edwin

    2015-02-16

    Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is due not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but, perhaps most crucially, the multitude of epidemiological, ecological, and socioeconomic factors that drive VBD transmission, and this complexity has generated considerable debate over the last 10-15 years. In this article, and Theme Issue, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions, and, crucially, offer some solutions for the field moving forwards. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems. This Theme Issue seeks to cover both, reflected in the breadth and depth of the topics and VBD-systems considered, itself strongly indicative of the challenging, but necessary, multidisciplinary nature of this research field.

  10. Land-Based Wind Potential Changes in the Southeastern United States (Presentation)

    SciTech Connect

    Roberts, J. O.

    2013-09-01

    Recent advancements in utility-scale wind turbine technology and pricing have vastly increased the potential land area where turbines can be deployed in the United States. This presentation quantifies the new developable land potential (e.g., capacity curves), visually identifies new areas for possible development (e.g., new wind resource maps), and begins to address deployment barriers to wind in new areas for modern and future turbine technology.

  11. Understanding future changes in Northern Hemisphere winter meridional wind and regional hydroclimate

    NASA Astrophysics Data System (ADS)

    Simpson, I.; Seager, R.; Ting, M.; Shaw, T.

    2015-12-01

    A critical aspect of human-induced climate change is how it will affect climatological mean and extreme precipitation around the world. To leading order, the increased ability of the atmosphere to hold moisture as it warms, intensifies moisture transports, making subtropical dry regions drier and tropical and mid- to high latitude wet regions wetter. But regionally, precipitation change will also depend on how the atmospheric circulation responds to warming. During Northern Hemisphere winter, climate models predict a robust (in terms of structure) change in the stationary wave field that brings wetting southerlies to the west coast of North America and drying northerlies to interior southwest North America and the Mediterranean. Here, the underlying cause of this change is investigated. Stationary wave model experiments reaveal that the strengthening of the zonal wind in the sub-tropical upper troposphere is primarily responsible through it's influence on the character of intermediate scale stationary waves. A robust and easily understood model response to global warming is, therefore, the prime cause and it should be expected to happen to some degree. However, there is considerable model diversity in the magnitude of the stationary wave response and almost 50% of the model spread over North America can be explained through this mechanistic understanding, allowing an improved estimate of where the real world will sit within the spectrum of model behavior. It is concluded that many models are likely overestimating the magnitude of this response and as a result, the wetting of the North American west coast and drying in the interior south west will likely be weaker than predicted by the majority of models and the multi-model mean. The implications of this for future predicted hydroclimate extremes will also be discussed.

  12. THE ABRUPT CHANGES IN THE PHOTOSPHERIC MAGNETIC AND LORENTZ FORCE VECTORS DURING SIX MAJOR NEUTRAL-LINE FLARES

    SciTech Connect

    Petrie, G. J. D.

    2012-11-01

    We analyze the spatial and temporal variations of the abrupt photospheric magnetic changes associated with six major flares using 12 minute, 0.''5 pixel{sup -1} vector magnetograms from NASA's Helioseismic and Magnetic Imager instrument on the Solar Dynamics Observatory satellite. The six major flares occurred near the main magnetic neutral lines of four active regions, NOAA 11158, 11166, 11283, and 11429. During all six flares the neutral-line field vectors became stronger and more horizontal, in each case almost entirely due to strengthening of the horizontal field components parallel to the neutral line. In all six cases the neutral-line pre-flare fields were more vertical than the reference potential fields, and collapsed abruptly and permanently closer to potential-field tilt angles during every flare, implying that the relaxation of magnetic stress associated with non-potential tilt angles plays a major role during major flares. The shear angle with respect to the reference potential field did not show such a pattern, demonstrating that flare processes do not generally relieve magnetic stresses associated with photospheric magnetic shear. The horizontal fields became significantly and permanently more aligned with the neutral line during the four largest flares, suggesting that the collapsing field is on average more aligned with the neutral line than the pre-flare neutral-line field. The vertical Lorentz force had a large, abrupt, permanent downward change during each of the flares, consistent with loop collapse. The horizontal Lorentz force changes acted mostly parallel to the neutral line in opposite directions on each side, a signature of the fields contracting during the flare, pulling the two sides of the neutral line toward each other. The greater effect of the flares on field tilt than on shear may be explained by photospheric line-tying.

  13. Potential impacts of topography and prevailing wind direction on future precipitation changes in Japan

    NASA Astrophysics Data System (ADS)

    Tsunematsu, N.; Dairaku, K.; Hirano, J.

    2013-12-01

    To investigate future changes in summertime precipitation amounts over the Japanese islands and their relations to the topographical heights, this study analyzed 20 km horizontal grid-spacing regional climate model downscalings of MIROC3.2-hires 20C3M and SRES-A1B scenario data for the periods of 1981-2000 and 2081-2100. Results indicate the remarkable increases in June-July-August mean daily precipitation in the west and south sides (windward sides) of the mountainous regions, especially in western Japan where heavy rainfall is frequently observed in the recent climate. The remarkable increases in summertime precipitation are likely to occur not only in high altitude areas but also at low altitudes. The occurrence frequencies of precipitation greater than 100 mm/day would also increase in such areas. The intensification of southwesterly moist air flows in the lower troposphere is considered to be one of the main causes of those precipitation changes because the intensified southwesterly moist air flows impinging on the western and southern slopes of the mountains can generate stronger upslope flows and well-developed clouds, leading to increased precipitation. Also, the results show that future precipitation changes in the lee sides of the mountainous regions (e.g., the Tokyo metropolitan area) would be comparatively small. These results indicate large influences of topography and prevailing wind direction on future precipitation changes. Acknowledgments: This study was conducted as part of the research subject "Vulnerability and Adaptation to Climate Change in Water Hazard Assessed Using Regional Climate Scenarios in the Tokyo Region' (National Research Institute for Earth Science and Disaster Prevention; PI: Koji Dairaku) of Research Program on Climate Change Adaptation (RECCA) and was supported by the SOUSEI Program, funded by Ministry of Education, Culture, Sports, Science and Technology, Government of Japan. We thank the regional climate modeling groups (MRI

  14. The National Assessment of Shoreline Change: A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the U.S. Gulf of Mexico

    USGS Publications Warehouse

    Miller, Tara L.; Morton, Robert A.; Sallenger, Asbury H.; Moore, Laura J.

    2004-01-01

    Introduction The Coastal and Marine Geology Program of the U.S. Geological Survey has generated a comprehensive database of digital vector shorelines and shoreline change rates for the U.S. Gulf of Mexico. These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Beach erosion is a chronic problem along most open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of shoreline migration. There is also a critical need for shoreline change data that is consistent from one coastal region to another. One purpose of this work is to develop standard repeatable methods for mapping and analyzing shoreline movement so that periodic updates regarding coastal erosion and land loss can be made nationally that are systematic and internally consistent. This data compilation for open-ocean, sandy shorelines of the Gulf of Mexico is the first in a series that will eventually include the Atlantic Coast, Pacific Coast, and parts of Hawaii and Alaska. Short- and long-term shoreline change evaluations are based on merging three historical shorelines with a modern shoreline derived from lidar (light detection and ranging) topographic surveys. Historical shorelines generally represent the following time periods: 1800s, 1920s-1930s, and 1970s. The most recent shoreline is derived from data collected over the period of 1998-2002. Long-term rates of change are calculated by linear regression using all four shorelines. Short-term rates of change are simple end-point rate calculations using the two most recent shorelines. Please refer to our full report on shoreline change in the Gulf of Mexico, National Assessment of Shoreline Change: Part 1, Historical Shoreline Changes and Associated Coastal Land Loss Along the U.S. Gulf of Mexico (USGS Open File

  15. The future of coastal upwelling ecosystems: the impact of potential wind changes on ocean acidification and coastal hypoxia

    NASA Astrophysics Data System (ADS)

    Lachkar, Z.; Gruber, N.

    2012-04-01

    The upwelling of deep, low pH, and low oxygen water to the surface makes eastern boundary upwelling systems (EBUS) naturally prone to global change induced perturbations such as ocean acidification and ocean deoxygentation related to decreased ocean ventilation. The severity of these chemical perturbations may further be exacerbated in EBUS by the potential increase in upwelling favorable winds induced by global warming. Here, we explore the impact of upwelling-favorable wind changes on modern and future ocean acidification and coastal hypoxia through a comparative study of the California Current System (California CS) and the Canary Current System (Canary CS). To this end, we undertook a series of idealized wind perturbation studies for present-day and year 2050 conditions with eddy-resolving setups of the Regional Oceanic Modeling System - ROMS- to which a nitrogen-based Nutrient-Phytoplankton-Detritus-Zooplankton (NPDZ) biogeochemical model was coupled. Our results show that the increase of upwelling favorable winds leads to a substantial shoaling of the hypoxic boundary in the California CS, while the same wind perturbation results in a reduction of the hypoxic water volume in the Canary CS. This is because coastal hypoxia is driven by local remineralization of organic matter on the shelf in the Canary CS, while it is essentially driven by large-scale advection of low oxygen water in the California CS. The intensification of upwelling tends to acerbate ocean acidification in the surface ocean, but mediates it below it, leading to complex change pattern reflecting the intricate interplay between biologically and physically -driven changes in calcium carbonate saturation state. Additionally, our results reveal differential biogeochemical responses to upwelling intensification in the water column and on the continental shelf with, therefore, contrasting implications for the benthic and the pelagic communities of these ecosystems.

  16. Population Genetics of Two Key Mosquito Vectors of Rift Valley Fever Virus Reveals New Insights into the Changing Disease Outbreak Patterns in Kenya

    PubMed Central

    Tchouassi, David P.; Bastos, Armanda D. S.; Sole, Catherine L.; Diallo, Mawlouth; Lutomiah, Joel; Mutisya, James; Mulwa, Francis; Borgemeister, Christian; Sang, Rosemary; Torto, Baldwyn

    2014-01-01

    Rift Valley fever (RVF) outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi) and newly-associated (Ae. ochraceus) vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification. PMID:25474018

  17. The National Assessment of Shoreline Change:A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the Sandy Shorelines of the California Coast

    USGS Publications Warehouse

    Hapke, Cheryl J.; Reid, David

    2006-01-01

    Introduction The Coastal and Marine Geology Program of the U.S. Geological Survey has generated a comprehensive data clearinghouse of digital vector shorelines and shoreline change rates for the sandy shoreline along the California open coast. These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Beach erosion is a chronic problem along many open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of shoreline migration. There is also a critical need for shoreline change data that is consistent from one coastal region to another. One purpose of this work is to develop standard, repeatable methods for mapping and analyzing shoreline movement so that periodic, systematic, and internally consistent updates of shorelines and shoreline change rates can be made at a National Scale. This data compilation for open-ocean, sandy shorelines of the California coast is one in a series that already includes the Gulf of Mexico and the Southeast Atlantic Coast (Morton et al., 2004; Morton et al., 2005) and will eventually cover Washington, Oregon, and parts of Hawaii and Alaska. Short- and long-term shoreline change evaluations are determined by comparing the positions of three historical shorelines digitized from maps, with a modern shoreline derived from LIDAR (light detection and ranging) topographic surveys. Historical shorelines generally represent the following time-periods: 1850s-1880s, 1920s-1930s, and late 1940s-1970s. The most recent shoreline is from data collected between 1997 and 2002. Long-term rates of change are calculated by linear regression using all four shorelines. Short-term rates of change are end-point rate calculations using the two most recent shorelines. Please refer to our full report on shoreline change of the

  18. Risk maps for range expansion of the Lyme disease vector, Ixodes scapularis, in Canada now and with climate change

    PubMed Central

    Ogden, Nicholas H; St-Onge, Laurie; Barker, Ian K; Brazeau, Stéphanie; Bigras-Poulin, Michel; Charron, Dominique F; Francis, Charles M; Heagy, Audrey; Lindsay, L Robbin; Maarouf, Abdel; Michel, Pascal; Milord, François; O'Callaghan, Christopher J; Trudel, Louise; Thompson, R Alex

    2008-01-01

    Background Lyme disease is the commonest vector-borne zoonosis in the temperate world, and an emerging infectious disease in Canada due to expansion of the geographic range of the tick vector Ixodes scapularis. Studies suggest that climate change will accelerate Lyme disease emergence by enhancing climatic suitability for I. scapularis. Risk maps will help to meet the public health challenge of Lyme disease by allowing targeting of surveillance and intervention activities. Results A risk map for possible Lyme endemicity was created using a simple risk algorithm for occurrence of I. scapularis populations. The algorithm was calculated for each census sub-division in central and eastern Canada from interpolated output of a temperature-driven simulation model of I. scapularis populations and an index of tick immigration. The latter was calculated from estimates of tick dispersion distances by migratory birds and recent knowledge of the current geographic range of endemic I. scapularis populations. The index of tick immigration closely predicted passive surveillance data on I. scapularis occurrence, and the risk algorithm was a significant predictor of the occurrence of I. scapularis populations in a prospective field study. Risk maps for I. scapularis occurrence in Canada under future projected climate (in the 2020s, 2050s and 2080s) were produced using temperature output from the Canadian Coupled Global Climate Model 2 with greenhouse gas emission scenario enforcing 'A2' of the Intergovernmental Panel on Climate Change. Conclusion We have prepared risk maps for the occurrence of I. scapularis in eastern and central Canada under current and future projected climate. Validation of the risk maps provides some confidence that they provide a useful first step in predicting the occurrence of I. scapularis populations, and directing public health objectives in minimizing risk from Lyme disease. Further field studies are needed, however, to continue validation and refinement

  19. Cytoplasmic calcium increases in response to changes in the gravity vector in hypocotyls and petioles of Arabidopsis seedlings.

    PubMed

    Toyota, Masatsugu; Furuichi, Takuya; Tatsumi, Hitoshi; Sokabe, Masahiro

    2008-02-01

    Plants respond to a large variety of environmental signals, including changes in the gravity vector (gravistimulation). In Arabidopsis (Arabidopsis thaliana) seedlings, gravistimulation is known to increase the cytoplasmic free calcium concentration ([Ca(2+)](c)). However, organs responsible for the [Ca(2+)](c) increase and the underlying cellular/molecular mechanisms remain to be solved. In this study, using Arabidopsis seedlings expressing apoaequorin, a Ca(2+)-sensitive luminescent protein in combination with an ultrasensitive photon counting camera, we clarified the organs where [Ca(2+)](c) increases in response to gravistimulation and characterized the physiological and pharmacological properties of the [Ca(2+)](c) increase. When the seedlings were gravistimulated by turning 180 degrees, they showed a transient biphasic [Ca(2+)](c) increase in their hypocotyls and petioles. The second peak of the [Ca(2+)](c) increase depended on the angle but not the speed of rotation, whereas the initial peak showed diametrically opposite characters. This suggests that the second [Ca(2+)](c) increase is specific for changes in the gravity vector. The potential mechanosensitive Ca(2+)-permeable channel (MSCC) inhibitors Gd(3+) and La(3+), the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), and the endomembrane Ca(2+)-permeable channel inhibitor ruthenium red suppressed the second [Ca(2+)](c) increase, suggesting that it arises from Ca(2+) influx via putative MSCCs in the plasma membrane and Ca(2+) release from intracellular Ca(2+) stores. Moreover, the second [Ca(2+)](c) increase was attenuated by actin-disrupting drugs cytochalasin B and latrunculin B but not by microtubule-disrupting drugs oryzalin and nocodazole, implying that actin filaments are partially involved in the hypothetical activation of Ca(2+)-permeable channels. These results suggest that the second [Ca(2+)](c) increase via MSCCs is a gravity response in the hypocotyl and

  20. Massachusetts shoreline change project: a GIS compilation of vector shorelines and associated shoreline change data for the 2013 update

    USGS Publications Warehouse

    Smith, Theresa L.; Himmelstoss, Emily A.; Thieler, E. Robert

    2013-01-01

    Identifying the rates and trends associated with the position of the shoreline through time presents vital information on potential impacts these changes may have on coastal populations and infrastructure, and supports informed coastal management decisions. This report publishes the historical shoreline data used to assess the scale and timing of erosion and accretion along the Massachusetts coast from New Hampshire to Rhode Island including all of Cape Cod, Martha’s Vineyard, Nantucket and the Elizabeth Islands. This data is an update to the Massachusetts Office of Coastal Zone Management Shoreline Change Project. Shoreline positions from the past 164 years (1845 to 2009) were used to compute the shoreline change rates. These data include a combined length of 1,804 kilometers of new shoreline data derived from color orthophoto imagery collected in 2008 and 2009, and topographic lidar collected in 2007. These new shorelines have been added to previously published historic shoreline data from the Massachusetts Office of Coastal Zone Management and the U.S. Geological Survey. A detailed report containing a discussion of the shoreline change data presented here and a summary of the resulting rates is available and cited at the end of the Introduction section of this report.

  1. National assessment of shoreline change: A GIS compilation of vector shorelines and associated shoreline change data for the sandy shorelines of Kauai, Oahu, and Maui, Hawaii

    USGS Publications Warehouse

    Romine, Bradley M.; Fletcher, Charles H.; Genz, Ayesha S.; Barbee, Matthew M.; Dyer, Matthew; Anderson, Tiffany R.; Lim, S. Chyn; Vitousek, Sean; Bochicchio, Christopher; Richmond, Bruce M.

    2012-01-01

    Sandy ocean beaches are a popular recreational destination, and often are surrounded by communities that consist of valuable real estate. Development is increasing despite the fact that coastal infrastructure may be repeatedly subjected to flooding and erosion. As a result, the demand for accurate information regarding past and present shoreline changes is increasing. Working with researchers from the University of Hawaii, investigators with the U.S. Geological Survey's National Assessment of Shoreline Change Project have compiled a comprehensive database of digital vector shorelines and shoreline-change rates for the islands of Kauai, Oahu, and Maui, Hawaii. No widely accepted standard for analyzing shoreline change currently exists. Current measurement and rate-calculation methods vary from study to study, precluding the combination of study results into statewide or regional assessments. The impetus behind the National Assessment was to develop a standardized method for measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the measurements in an internally consistent manner. A detailed report on shoreline change for Kauai, Maui, and Oahu that contains a discussion of the data presented here is available and cited in the Geospatial Data section of this report.

  2. Analysis of change in the wind speed ratio according to apartment layout and solutions.

    PubMed

    Hyung, Won-gil; Kim, Young-Moon; You, Ki-Pyo

    2014-01-01

    Apartment complexes in various forms are built in downtown areas. The arrangement of an apartment complex has great influence on the wind flow inside it. There are issues of residents' walking due to gust occurrence within apartment complexes, problems with pollutant emission due to airflow congestion, and heat island and cool island phenomena in apartment complexes. Currently, the forms of internal arrangements of apartment complexes are divided into the flat type and the tower type. In the present study, a wind tunnel experiment and computational fluid dynamics (CFD) simulation were performed with respect to internal wind flows in different apartment arrangement forms. Findings of the wind tunnel experiment showed that the internal form and arrangement of an apartment complex had significant influence on its internal airflow. The wind velocity of the buildings increased by 80% at maximum due to the proximity effects between the buildings. The CFD simulation for relaxing such wind flows indicated that the wind velocity reduced by 40% or more at maximum when the paths between the lateral sides of the buildings were extended.

  3. Two approaches for incorporating climate change into natural resource management planning at Wind Cave National Park

    USGS Publications Warehouse

    Symstad, Amy; Long, Andrew J.; Stamm, John; King, David A.; Bachelet, Dominque M.; Norton, Parker A.

    2014-01-01

    Wind Cave National Park (WICA) protects one of the world’s longest caves, has large amounts of high quality, native vegetation, and hosts a genetically important bison herd. The park’s relatively small size and unique purpose within its landscape requires hands-on management of these and other natural resources, all of which are interconnected. Anthropogenic climate change presents an added challenge to WICA natural resource management because it is characterized by large uncertainties, many of which are beyond the control of park and National Park Service (NPS) staff. When uncertainty is high and control of this uncertainty low, scenario planning is an appropriate tool for determining future actions. In 2009, members of the NPS obtained formal training in the use of scenario planning in order to evaluate it as a tool for incorporating climate change into NPS natural resource management planning. WICA served as one of two case studies used in this training exercise. Although participants in the training exercise agreed that the scenario planning process showed promise for its intended purpose, they were concerned that the process lacked the scientific rigor necessary to defend the management implications derived from it in the face of public scrutiny. This report addresses this concern and others by (1) providing a thorough description of the process of the 2009 scenario planning exercise, as well as its results and management implications for WICA; (2) presenting the results of a follow-up, scientific study that quantitatively simulated responses of WICA’s hydrological and ecological systems to specific climate projections; (3) placing these climate projections and the general climate scenarios used in the scenario planning exercise in the broader context of available climate projections; and (4) comparing the natural resource management implications derived from the two approaches. Wind Cave National Park (WICA) protects one of the world’s longest caves

  4. Ground magnetic response to sudden changes in the solar wind dynamic pressure and interplanetary magnetic field orientation

    NASA Astrophysics Data System (ADS)

    Sitar, Robert John

    1999-12-01

    Most, if not all, of the early research on impulsive magnetic events at high latitudes focused on first identifying the events in ground magnetic recordings and then examining the solar wind properties in search of a common link between different events. The results of these types of studies were often inconclusive and open to debate. The work presented here attacks the problem from the opposite point of view, namely by identifying changes within the solar wind and then examining the resulting ground magnetic signatures. This is accomplished using a combination of ground-based magnetic measurements from arrays of magnetometers located in Greenland and IMP 8 satellite measurements of the solar wind velocity, density, and magnetic field orientation. The study of solar wind dynamic pressure changes uses data collected by the IMP 8 satellite during 1991 and 1992 and focuses on step changes in dynamic pressure of |Dp|>2 nPa occurring on a timescale of Dt<15 min. It has been observed that the ground response does not consistently conform to existing theoretical models of field-aligned currents generated by changes in dynamic pressure. No explicit dependence on interplanetary magnetic field orientation (IMF) has been found. The relationship between IMF orientation changes and magnetic impulse events is highlighted by a case study of an IMF orientation change occurring on July 24, 1996. The effects of the IMF orientation change are observed in ground magnetometer data, incoherent scatter radar measurements, and auroral ultraviolet emissions. It is believed the ground observations result from the interaction of a hot flow anomaly with the magnetopause. These observations are the first of their kind and provide a mechanism to tie an IMF orientation change into the existing theory that traveling convection vortices result from a deformation of the magnetopause. The study of IMF orientation changes uses data from the IMP 8 satellite collected between 1992 and 1995. We have

  5. The trophic responses of two different rodent-vector-plague systems to climate change.

    PubMed

    Xu, Lei; Schmid, Boris V; Liu, Jun; Si, Xiaoyan; Stenseth, Nils Chr; Zhang, Zhibin

    2015-02-07

    Plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. Without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. Here, by using surveillance data, we apply structural equation modelling to reveal the drivers of plague prevalence in two very different rodent systems: those of the solitary Daurian ground squirrel and the social Mongolian gerbil. We show that plague prevalence in the Daurian ground squirrel is not detectably related to its trophic web, and that therefore surveillance efforts should focus on detecting plague directly in this ecosystem. On the other hand, plague in the Mongolian gerbil is strongly embedded in a complex, yet understandable trophic web of climate, vegetation, and rodent and flea densities, making the ecosystem suitable for more sophisticated low-cost surveillance practices, such as remote sensing. As for the trophic webs of the two rodent species, we find that increased vegetation is positively associated with higher temperatures and precipitation for both ecosystems. We furthermore find a positive association between vegetation and ground squirrel density, yet a negative association between vegetation and gerbil density. Our study thus shows how past surveillance records can be used to design and improve existing plague prevention and control measures, by tailoring them to individual plague foci. Such measures are indeed highly needed under present conditions with prevailing climate change.

  6. Dynamic changes of spatial functional network connectivity in healthy individuals and schizophrenia patients using independent vector analysis.

    PubMed

    Ma, Sai; Calhoun, Vince D; Phlypo, Ronald; Adalı, Tülay

    2014-04-15

    Recent work on both task-induced and resting-state functional magnetic resonance imaging (fMRI) data suggests that functional connectivity may fluctuate, rather than being stationary during an entire scan. Most dynamic studies are based on second-order statistics between fMRI time series or time courses derived from blind source separation, e.g., independent component analysis (ICA), to investigate changes of temporal interactions among brain regions. However, fluctuations related to spatial components over time are of interest as well. In this paper, we examine higher-order statistical dependence between pairs of spatial components, which we define as spatial functional network connectivity (sFNC), and changes of sFNC across a resting-state scan. We extract time-varying components from healthy controls and patients with schizophrenia to represent brain networks using independent vector analysis (IVA), which is an extension of ICA to multiple data sets and enables one to capture spatial variations. Based on mutual information among IVA components, we perform statistical analysis and Markov modeling to quantify the changes in spatial connectivity. Our experimental results suggest significantly more fluctuations in patient group and show that patients with schizophrenia have more variable patterns of spatial concordance primarily between the frontoparietal, cerebellar and temporal lobe regions. This study extends upon earlier studies showing temporal connectivity differences in similar areas on average by providing evidence that the dynamic spatial interplay between these regions is also impacted by schizophrenia.

  7. Climate and Population Health Vulnerabilities to Vector-Borne Diseases: Increasing Resilience Under Climate Change Conditions in Africa

    NASA Astrophysics Data System (ADS)

    Ceccato, P.; McDonald, K. C.; Podest, E.; De La Torre Juarez, M.; Kruczkiewicz, A.; Lessel, J.; Jensen, K.; Thomson, M. C.

    2014-12-01

    The International Research Institute for Climate and Society (IRI), the City University of New York (CUNY) and NASA Jet Propulsion Laboratory (JPL) in collaboration with NASA SERVIR are developing tools to monitor climate variables (precipitation, temperature, vegetation, water bodies, inundation) that help projects in Africa to increase resilience to climate change for vector-borne diseases (i.e. malaria, trypanosomiasis, leishmaniasis, and schistosomiasis). Through the development of new products to monitor precipitation, water bodies and inundation, IRI, CUNY and JPL provide tools and capacity building to research communities, ministries of health and World Health Organization in Africa to: 1) Develop research teams' ability to appropriately use climate data as part of their research 2) Enable research teams and ministries to integrate climate information into social and economic drivers of vulnerability and opportunities for adaptation to climate change 3) Inform better policies and programs for climate change adaptation. This oral presentation will demonstrate how IRI, CUNY, and JPL developed new products, tools and capacity building to achieve the three objectives mentioned above.

  8. Climate and Health Vulnerability to Vector-Borne Diseases: Increasing Resilience under Climate Change Conditions in Africa

    NASA Astrophysics Data System (ADS)

    Ceccato, P.

    2015-12-01

    The International Research Institute for Climate and Society (IRI), the City University of New York (CUNY) and NASA Jet Propulsion Laboratory (JPL) in collaboration with NASA SERVIR are developing tools to monitor climate variables (precipitation, temperature, vegetation, water bodies, inundation) that help projects in Africa to increase resilience to climate change for vector-borne diseases ( malaria, trypanosomiasis, leishmaniasis, and schistosomiasis). Through the development of new products to monitor precipitation, water bodies and inundation, IRI, CUNY and JPL provide tools and capacity building to research communities; ministries of health; the WMO Global Framework for Climate and Services; and World Health Organization in Africa to: 1) Develop research teams' ability to appropriately use climate data as part of their research 2) Enable research teams and ministries to integrate climate information into social and economic drivers of vulnerability and opportunities for adaptation to climate change 3) Inform better policies and programs for climate change adaptation. This oral presentation will demonstrate how IRI, CUNY, and JPL developed new products, tools and capacity building to achieve the three objectives mentioned above with examples in South Africa, Zimbabwe, Tanzania and Malawi.

  9. Feline leukemia virus integrase and capsid packaging functions do not change the insertion profile of standard Moloney retroviral vectors.

    PubMed

    Métais, J-Y; Topp, S; Doty, R T; Borate, B; Nguyen, A-D; Wolfsberg, T G; Abkowitz, J L; Dunbar, C E

    2010-06-01

    Adverse events linked to perturbations of cellular genes by vector insertion reported in gene therapy trials and animal models have prompted attempts to better understand the mechanisms directing viral vector integration. The integration profiles of vectors based on MLV, ASLV, SIV and HIV have all been shown to be non-random, and novel vectors with a safer integration pattern have been sought. Recently, we developed a producer cell line called CatPac that packages standard MoMLV vectors with feline leukemia virus (FeLV) gag, pol and env gene products. We now report the integration profile of this vector, asking if the FeLV integrase and capsid proteins could modify the MoMLV integration profile, potentially resulting in a less genotoxic pattern. We transduced rhesus macaque CD34+ hematopoietic progenitor cells with CatPac or standard MoMLV vectors, and determined their integration profile by LAM-PCR. We obtained 184 and 175 unique integration sites (ISs) respectively for CatPac and standard MoMLV vectors, and these were compared with 10 000 in silico-generated random IS. The integration profile for CatPac vector was similar to MoMLV and equally non-random, with a propensity for integration near transcription start sites and in highly dense gene regions. We found an IS for CatPac vector localized 715 nucleotides upstream of LMO-2, the gene involved in the acute lymphoblastic leukemia developed by X-SCID patients treated by gene therapy using MoMLV vectors. In conclusion, we found that replacement of MoMLV env, gag and pol gene products with FeLV did not alter the basic integration profile. Thus, there appears to be no safety advantage for this packaging system. However, considering the stability and efficacy of CatPac vectors, further development is warranted, using potentially safer vector backbones, for instance those with a SIN configuration.

  10. A Change of Inertia-Supporting the Thrust Vector Control of the Space Launch System

    NASA Technical Reports Server (NTRS)

    Dziubanek, Adam J.

    2012-01-01

    The Space Launch System (SLS) is America's next launch vehicle. To utilize the vehicle more economically, heritage hardware from the Space Transportation System (STS) will be used when possible. The Solid Rocket Booster (SRB) actuators could possibly be used in the core stage of the SLS. The dynamic characteristics of the SRB actuator will need to be tested on an Inertia Load Stand (ILS) that has been converted to Space Shuttle Main Engine (SSME). The inertia on the pendulum of the ILS will need to be changed to match the SSME inertia. In this testing environment an SRB actuator can be tested with the equivalent resistence of an SSME.

  11. Influence of long-term gravity vector changes on mesenchymal stem cells in vitro

    NASA Astrophysics Data System (ADS)

    Buravkova, L. B.; Merzlikina, N. V.; Romanov, Yu. A.; Buravkov, S. V.

    2005-08-01

    In vivo and in vitro studies have identified the bone marrow as the primary source of a multipotential mesenchymal stem cells (MSC) that give rise to progenitors for several mesenchymal tissues, including bone, cartilage, tendon, adipose, muscle and hematopoietic-supporting stroma. It is known that MSC are sensitive to chemical signals and mechanical stimuli. It was also suggested that microgravity may influence on progenitor cells and induce abnormalities in cellular differentiation in muscle and skeletal components leading to the changes in physiological regeneration of these tissues. To prove gravitational sensitivity of MSC, we studied the effects of prolonged clinorotation on cultured human MSC (hMSC) morphology, actin cytoskeleton organization and phenotype. It was found that the proliferation rate was significantly decreased during clinorotation but augmented during recovery. The cell cytoskeleton displayed actin filament thinning and altered morphology at clinorotation. The production of interleukin-6 was increased and expression of surface molecules was modified by simulated microgravity. Observed changes of cultured hMSC behavior suggest the gravitational sensitivity of human stromal progenitor cells.

  12. Aerobiology of Artemisia airborne pollen in Murcia (SE Spain) and its relationship with weather variables: annual and intradiurnal variations for three different species. Wind vectors as a tool in determining pollen origin

    NASA Astrophysics Data System (ADS)

    Giner, M. Munuera; Carrión García, José S.; García Sellés, Javier

    Detailed results from a 2-year survey of airborne pollen concentrations of Artemisia in Murcia are presented. Three consecutive pollen seasons of Artemisia occurring each year, related to three different species (A.campestris, A.herba-alba and A.barrelieri), were observed. A winter blooming of Artemisia could explain the incidence of subsequent pollinosis in the Murcia area. With regard to meteorological parameters, mathematical analyses showed relationships between daily pollen concentrations of Artemisia in summer-autumn and precipitations that occurred 6-8 weeks before. The cumulative percentage of insolation from 1 March seemed to be related to blooming onsets. Once pollination has begun, meteorological factors do not seem to influence pollen concentrations significantly. Intradiurnal patterns of pollen concentrations were similar for late summer and winter species (A. campestris and A.barrelieri). During autumn blooming (A.herba-alba), the intradiurnal pattern was particularly erratic. Theoretical values of wind run were obtained for each pollen season by the graphical sum of hourly wind vectors. When theoretical wind run was mapped onto the vegetation pattern, supposed pollen source locations were obtained for each hour. By comparing supposed hourly pollen origins with the intradiurnal patterns of pollen concentrations, it can be seen that this simple model explains variations in mean pollen concentrations throughout the day.

  13. Ecological Niche Modelling Predicts Southward Expansion of Lutzomyia (Nyssomyia) flaviscutellata (Diptera: Psychodidae: Phlebotominae), Vector of Leishmania (Leishmania) amazonensis in South America, under Climate Change.

    PubMed

    Carvalho, Bruno M; Rangel, Elizabeth F; Ready, Paul D; Vale, Mariana M

    2015-01-01

    Vector borne diseases are susceptible to climate change because distributions and densities of many vectors are climate driven. The Amazon region is endemic for cutaneous leishmaniasis and is predicted to be severely impacted by climate change. Recent records suggest that the distributions of Lutzomyia (Nyssomyia) flaviscutellata and the parasite it transmits, Leishmania (Leishmania) amazonensis, are expanding southward, possibly due to climate change, and sometimes associated with new human infection cases. We define the vector's climatic niche and explore future projections under climate change scenarios. Vector occurrence records were compiled from the literature, museum collections and Brazilian Health Departments. Six bioclimatic variables were used as predictors in six ecological niche model algorithms (BIOCLIM, DOMAIN, MaxEnt, GARP, logistic regression and Random Forest). Projections for 2050 used 17 general circulation models in two greenhouse gas representative concentration pathways: "stabilization" and "high increase". Ensemble models and consensus maps were produced by overlapping binary predictions. Final model outputs showed good performance and significance. The use of species absence data substantially improved model performance. Currently, L. flaviscutellata is widely distributed in the Amazon region, with records in the Atlantic Forest and savannah regions of Central Brazil. Future projections indicate expansion of the climatically suitable area for the vector in both scenarios, towards higher latitudes and elevations. L. flaviscutellata is likely to find increasingly suitable conditions for its expansion into areas where human population size and density are much larger than they are in its current locations. If environmental conditions change as predicted, the range of the vector is likely to expand to southeastern and central-southern Brazil, eastern Paraguay and further into the Amazonian areas of Bolivia, Peru, Ecuador, Colombia and Venezuela

  14. Changing Snow Cover and Stream Discharge in the Western United States - Wind River Range, Wyoming

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Barton, Jonathan S.; Riggs, George A.

    2011-01-01

    Earlier onset of springtime weather has been documented in the western United States over at least the last 50 years. Because the majority (>70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack has important implications for the management of water resources. We studied ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover products, 40 years of stream discharge and meteorological station data and 30 years of snow-water equivalent (SWE) SNOw Telemetry (SNOTEL) data in the Wind River Range (WRR), Wyoming. Results show increasing air temperatures for.the 40-year study period. Discharge from streams in WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades. Changes in streamflow may be related to increasing air temperatures which are probably contributing to a reduction in snow cover, although no trend of either increasingly lower streamflow or earlier snowmelt was observed within the decade of the 2000s. And SWE on 1 April does not show an expected downward trend from 1980 to 2009. The extent of snow cover derived from the lowest-elevation zone of the WRR study area is strongly correlated (r=0.91) with stream discharge on 1 May during the decade of the 2000s. The strong relationship between snow cover and streamflow indicates that MODIS snow-cover maps can be used to improve management of water resources in the drought-prone western U.S.

  15. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission

    PubMed Central

    Parham, Paul E.; Waldock, Joanna; Christophides, George K.; Hemming, Deborah; Agusto, Folashade; Evans, Katherine J.; Fefferman, Nina; Gaff, Holly; Gumel, Abba; LaDeau, Shannon; Lenhart, Suzanne; Mickens, Ronald E.; Naumova, Elena N.; Ostfeld, Richard S.; Ready, Paul D.; Thomas, Matthew B.; Velasco-Hernandez, Jorge; Michael, Edwin

    2015-01-01

    Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10–15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector–pathogen systems. PMID:25688012

  16. The impacts of land use change on malaria vector abundance in a water-limited, highland region of Ethiopia.

    PubMed

    Stryker, Jody J; Bomblies, Arne

    2012-12-01

    Changes in land use and climate are expected to alter the risk of malaria transmission in areas where rainfall limits vector abundance. We use a coupled hydrology-entomology model to investigate the effects of land use change on hydrological processes impacting mosquito abundance in a highland village of Ethiopia. Land use affects partitioning of rainfall into infiltration and runoff that reaches small-scale topographic depressions, which constitute the primary breeding habitat of Anopheles arabiensis mosquitoes. A physically based hydrology model isolates hydrological mechanisms by which land use impacts pool formation and persistence, and an agent-based entomology model evaluates the response of mosquito populations. This approach reproduced observed interannual variability in mosquito abundance between the 2009 and 2010 wet seasons. Several scenarios of land cover were then evaluated using the calibrated, field-validated model. Model results show variation in pool persistence and depth, as well as in mosquito abundance, due to land use changes alone. The model showed particular sensitivity to surface roughness, but also to root zone uptake. Scenarios in which land use was modified from agriculture to forest generally resulted in lowest mosquito abundance predictions; classification of the entire domain as rainforest produced a 34% decrease in abundance compared to 2010 results. This study also showed that in addition to vegetation type, spatial proximity of land use change to habitat locations has an impact on mosquito abundance. This modeling approach can be applied to assess impacts of climate and land use conditions that fall outside of the range of previously observed variability.

  17. Climate change and vector-borne diseases: what are the implications for public health research and policy?

    PubMed Central

    Campbell-Lendrum, Diarmid; Manga, Lucien; Bagayoko, Magaran; Sommerfeld, Johannes

    2015-01-01

    Vector-borne diseases continue to contribute significantly to the global burden of disease, and cause epidemics that disrupt health security and cause wider socioeconomic impacts around the world. All are sensitive in different ways to weather and climate conditions, so that the ongoing trends of increasing temperature and more variable weather threaten to undermine recent global progress against these diseases. Here, we review the current state of the global public health effort to address this challenge, and outline related initiatives by the World Health Organization (WHO) and its partners. Much of the debate to date has centred on attribution of past changes in disease rates to climate change, and the use of scenario-based models to project future changes in risk for specific diseases. While these can give useful indications, the unavoidable uncertainty in such analyses, and contingency on other socioeconomic and public health determinants in the past or future, limit their utility as decision-support tools. For operational health agencies, the most pressing need is the strengthening of current disease control efforts to bring down current disease rates and manage short-term climate risks, which will, in turn, increase resilience to long-term climate change. The WHO and partner agencies are working through a range of programmes to (i) ensure political support and financial investment in preventive and curative interventions to bring down current disease burdens; (ii) promote a comprehensive approach to climate risk management; (iii) support applied research, through definition of global and regional research agendas, and targeted research initiatives on priority diseases and population groups. PMID:25688013

  18. Climate change and vector-borne diseases: what are the implications for public health research and policy?

    PubMed

    Campbell-Lendrum, Diarmid; Manga, Lucien; Bagayoko, Magaran; Sommerfeld, Johannes

    2015-04-05

    Vector-borne diseases continue to contribute significantly to the global burden of disease, and cause epidemics that disrupt health security and cause wider socioeconomic impacts around the world. All are sensitive in different ways to weather and climate conditions, so that the ongoing trends of increasing temperature and more variable weather threaten to undermine recent global progress against these diseases. Here, we review the current state of the global public health effort to address this challenge, and outline related initiatives by the World Health Organization (WHO) and its partners. Much of the debate to date has centred on attribution of past changes in disease rates to climate change, and the use of scenario-based models to project future changes in risk for specific diseases. While these can give useful indications, the unavoidable uncertainty in such analyses, and contingency on other socioeconomic and public health determinants in the past or future, limit their utility as decision-support tools. For operational health agencies, the most pressing need is the strengthening of current disease control efforts to bring down current disease rates and manage short-term climate risks, which will, in turn, increase resilience to long-term climate change. The WHO and partner agencies are working through a range of programmes to (i) ensure political support and financial investment in preventive and curative interventions to bring down current disease burdens; (ii) promote a comprehensive approach to climate risk management; (iii) support applied research, through definition of global and regional research agendas, and targeted research initiatives on priority diseases and population groups.

  19. The Impacts of Land Use Change on Malaria Vector Abundance in a Water-Limited Highland Region of Ethiopia

    NASA Astrophysics Data System (ADS)

    Stryker, J.; Bomblies, A.

    2012-12-01

    Changes in land use and climate are expected to alter risk of malaria transmission in areas where rainfall limits vector abundance. We use a coupled hydrology-entomology model to investigate the effects of land use change on hydrological processes impacting mosquito abundance in a highland village of Ethiopia. Land use affects partitioning of rainfall into infiltration and runoff that reaches small-scale topographic depressions, which constitute the primary breeding habitat of Anopheles arabiensis mosquitoes. A physically-based hydrology model isolates hydrological mechanisms by which land use impacts pool formation and persistence, and an agent-based entomology model evaluates the response of mosquito populations. This approach reproduced observed interannual variability in mosquito abundance between the 2009 and 2010 wet seasons. Several scenarios of land cover were then evaluated using the calibrated, field-validated model. Model results show variation in pool persistence and depth, as well as in mosquito abundance, due to land use changes alone. The model showed particular sensitivity to surface roughness, but also to root zone uptake. Scenarios in which land use was modified from agriculture to forest generally resulted in lowest mosquito abundance predictions; classification of the entire domain as rainforest produced a 34% decrease in abundance compared to 2010 results. This study also showed that in addition to vegetation type, spatial proximity of land use change to habitat locations has an impact on mosquito abundance. This modeling approach can be applied to assess impacts of climate and land use conditions that fall outside of the range of previously observed variability.

  20. Changing vessel routes could significantly reduce the cost of future offshore wind projects.

    PubMed

    Samoteskul, Kateryna; Firestone, Jeremy; Corbett, James; Callahan, John

    2014-08-01

    With the recent emphasis on offshore wind energy Coastal and Marine Spatial Planning (CMSP) has become one of the main frameworks used to plan and manage the increasingly complex web of ocean and coastal uses. As wind development becomes more prevalent, existing users of the ocean space, such as commercial shippers, will be compelled to share their historically open-access waters with these projects. Here, we demonstrate the utility of using cost-effectiveness analysis (CEA) to support siting decisions within a CMSP framework. In this study, we assume that large-scale offshore wind development will take place in the US Mid-Atlantic within the next decades. We then evaluate whether building projects nearshore or far from shore would be more cost-effective. Building projects nearshore is assumed to require rerouting of the commercial vessel traffic traveling between the US Mid-Atlantic ports by an average of 18.5 km per trip. We focus on less than 1500 transits by large deep-draft vessels. We estimate that over 29 years of the study, commercial shippers would incur an additional $0.2 billion (in 2012$) in direct and indirect costs. Building wind projects closer to shore where vessels used to transit would generate approximately $13.4 billion (in 2012$) in savings. Considering the large cost savings, modifying areas where vessels transit needs to be included in the portfolio of policies used to support the growth of the offshore wind industry in the US.

  1. Climate change projected fire weather sensitivity: CaliforniaSanta Ana wind occurrence

    SciTech Connect

    Miller, Norman L.; Schlegel, Nicole J.

    2006-01-01

    A new methodbased on global climate model pressuregradients was developed for identifying coastal high-wind fire weatherconditions, such as the Santa Ana Occurrence (SAO). Application of thismethod for determining southern California Santa Ana wind occurrenceresulted in a good correlation between derived large-scale SAOs andobserved offshore winds during periods of low humidity. The projectedchange in the number of SAOs was analyzed using two global climatemodels, one a low temperature sensitivity and the other amiddle-temperature sensitivity, both forced with low and high emissionscenarios, for three future time periods. This initial analysis showsconsistent shifts in SAO events from earlier (September-October) to later(November-December) in the season, suggesting that SAOs may significantlyincrease the extent of California coastal areas burned by wildfires, lossof life, and property.

  2. Variability in prevailing wind patterns during the Quaternary based on yardang morphology in the Qaidam Basin, China, and implications for climate change

    NASA Astrophysics Data System (ADS)

    Stubblefield, R. K.; Heermance, R. V., III

    2015-12-01

    The Qaidam Basin (QB) in the NE Tibetan Plateau provides an exceptional example of an aeolian landscape, comprised of wind-scoured bedrock, yardangs, and sand dunes. Yardangs are elongated ridges, eroded into bedrock, that have a blunt windward end and a leeward end that tapers in the direction of wind flow. A change in wind direction may truncate or overprint older yardangs with new landforms, or a drop-off in wind speed may halt erosion and provide time to develop a soil on the yardang surface. Analysis of 158 yardangs from Google Earth imagery reveals at least three generations of yardangs in the QB, which suggests great shifts in wind paths over time. In addition, 97 dunes were measured to assess present wind direction. The majority of the studied yardangs (n=104) were shaped by NW winds (mean azimuth 140°), consistent with present wind directions based on dune morphology and weather station data. A second generation of yardangs (n=42; mean azimuth 180°) does not align with the present wind regime, and is in places cut by modern landforms, in addition to exhibiting windward erosion from present winds. The oldest evidence for wind erosion is observed from "paleoyardangs" (n=12) that appear to be much older ridges that were buried and then re-exhumed. These paleoyardangs are aligned at roughly 100° and suggest an ancient, westerly wind path. These three populations of yardangs likely record three distinct wind regimes: a recent, Holocene path coming from the NW; an earlier, possibly glacial period, path originating due north and fanning out to the south; and a third, much older, westerly path, resulting from a different climatic or topographic setting. Our data reveal the utility of yardangs as paleoclimate indicators, and thus provides a framework to evaluate Quaternary atmospheric circulation.

  3. An evidence for prompt electric field disturbance driven by changes in the solar wind density under northward IMF Bz condition

    NASA Astrophysics Data System (ADS)

    Rout, Diptiranjan; Chakrabarty, D.; Sekar, R.; Reeves, G. D.; Ruohoniemi, J. M.; Pant, Tarun K.; Veenadhari, B.; Shiokawa, K.

    2016-05-01

    Before the onset of a geomagnetic storm on 22 January 2012 (Ap = 24), an enhancement in solar wind number density from 10/cm3 to 22/cm3 during 0440-0510 UT under northward interplanetary magnetic field (IMF Bz) condition is shown to have enhanced the high-latitude ionospheric convection and also caused variations in the geomagnetic field globally. Conspicuous changes in ΔX are observed not only at longitudinally separated low-latitude stations over Indian (prenoon), South American (midnight), Japanese (afternoon), Pacific (afternoon) and African (morning) sectors but also at latitudinally separated stations located over high and middle latitudes. The latitudinal variation of the amplitude of the ΔX during 0440-0510 UT is shown to be consistent with the characteristics of prompt penetration electric field disturbances. Most importantly, the density pulse event caused enhancements in the equatorial electrojet strength and the peak height of the F layer (hmF2) over the Indian dip equatorial sector. Further, the concomitant enhancements in electrojet current and F layer movement over the dip equator observed during this space weather event suggest a common driver of prompt electric field disturbance at this time. Such simultaneous variations are found to be absent during magnetically quiet days. In absence of significant change in solar wind velocity and magnetospheric substorm activity, these observations point toward perceptible prompt electric field disturbance over the dip equator driven by the overcompression of the magnetosphere by solar wind density enhancement.

  4. Econometric analysis of the changing effects in wind strength and significant wave height on the probability of casualty in shipping.

    PubMed

    Knapp, Sabine; Kumar, Shashi; Sakurada, Yuri; Shen, Jiajun

    2011-05-01

    This study uses econometric models to measure the effect of significant wave height and wind strength on the probability of casualty and tests whether these effects changed. While both effects are in particular relevant for stability and strength calculations of vessels, it is also helpful for the development of ship construction standards in general to counteract increased risk resulting from changing oceanographic conditions. The authors analyzed a unique dataset of 3.2 million observations from 20,729 individual vessels in the North Atlantic and Arctic regions gathered during the period 1979-2007. The results show that although there is a seasonal pattern in the probability of casualty especially during the winter months, the effect of wind strength and significant wave height do not follow the same seasonal pattern. Additionally, over time, significant wave height shows an increasing effect in January, March, May and October while wind strength shows a decreasing effect, especially in January, March and May. The models can be used to simulate relationships and help understand the relationships. This is of particular interest to naval architects and ship designers as well as multilateral agencies such as the International Maritime Organization (IMO) that establish global standards in ship design and construction.

  5. Thermal and Pressure Characterization of a Wind Tunnel Force Balance Using the Single Vector System. Experimental Design and Analysis Approach to Model Pressure and Temperature Effects in Hypersonic Wind Tunnel Research

    NASA Technical Reports Server (NTRS)

    Lynn, Keith C.; Commo, Sean A.; Johnson, Thomas H.; Parker, Peter A,

    2011-01-01

    Wind tunnel research at NASA Langley Research Center s 31-inch Mach 10 hypersonic facility utilized a 5-component force balance, which provided a pressurized flow-thru capability to the test article. The goal of the research was to determine the interaction effects between the free-stream flow and the exit flow from the reaction control system on the Mars Science Laboratory aeroshell during planetary entry. In the wind tunnel, the balance was exposed to aerodynamic forces and moments, steady-state and transient thermal gradients, and various internal balance cavity pressures. Historically, these effects on force measurement accuracy have not been fully characterized due to limitations in the calibration apparatus. A statistically designed experiment was developed to adequately characterize the behavior of the balance over the expected wind tunnel operating ranges (forces/moments, temperatures, and pressures). The experimental design was based on a Taylor-series expansion in the seven factors for the mathematical models. Model inversion was required to calculate the aerodynamic forces and moments as a function of the strain-gage readings. Details regarding transducer on-board compensation techniques, experimental design development, mathematical modeling, and wind tunnel data reduction are included in this paper.

  6. Spatial and temporal changes in Lutzomyia longipalpis abundance, a Leishmania infantum vector in an urban area in northeastern Argentina.

    PubMed

    Fernández, María Soledad; Santini, María Soledad; Cavia, Regino; Sandoval, Adolfo Enrique; Pérez, Adriana Alicia; Acardi, Soraya; Salomón, Oscar Daniel

    2013-11-01

    This study aimed to analyse changes in the spatial distribution of Lutzomyia longipalpis in Posadas, an urban area located in northeastern Argentina. Data were obtained during the summer of 2007 and 2009 through two entomological surveys of peridomiciles distributed around the city. The abundance distribution pattern for 2009 was computed and compared with the previous pattern obtained in 2007, when the first human visceral leishmaniasis cases were reported in the city. Vector abundance was also examined in relation to micro and macrohabitat characteristics. In 2007 and 2009, Lu. longipalpis was distributed among 41.5% and 31% of the households in the study area, respectively. In both years, the abundance rates at most of the trapping sites were below 30 Lu. longipalpis per trap per night; however, for areas exhibiting 30-60 Lu. longipalpis and more than 60 Lu. longipalpis, the areas increased in both size and number from 2007-2009. Lu. longipalpis was more abundant in areas with a higher tree and bush cover (a macrohabitat characteristic) and in peridomiciles with accumulated unused material (a microhabitat characteristic). These results will help to prioritise and focus control efforts by defining which peridomiciles display a potentially high abundance of Lu. longipalpis.

  7. Spatial and temporal changes in Lutzomyia longipalpis abundance, a Leishmania infantum vector in an urban area in northeastern Argentina

    PubMed Central

    Fernández, María Soledad; Santini, María Soledad; Cavia, Regino; Sandoval, Adolfo Enrique; Pérez, Adriana Alicia; Acardi, Soraya; Salomón, Oscar Daniel

    2013-01-01

    This study aimed to analyse changes in the spatial distribution of Lutzomyia longipalpis in Posadas, an urban area located in northeastern Argentina. Data were obtained during the summer of 2007 and 2009 through two entomological surveys of peridomiciles distributed around the city. The abundance distribution pattern for 2009 was computed and compared with the previous pattern obtained in 2007, when the first human visceral leishmaniasis cases were reported in the city. Vector abundance was also examined in relation to micro and macrohabitat characteristics. In 2007 and 2009, Lu. longipalpis was distributed among 41.5% and 31% of the households in the study area, respectively. In both years, the abundance rates at most of the trapping sites were below 30 Lu. longipalpis per trap per night; however, for areas exhibiting 30-60 Lu. longipalpis and more than 60 Lu. longipalpis, the areas increased in both size and number from 2007-2009. Lu. longipalpis was more abundant in areas with a higher tree and bush cover (a macrohabitat characteristic) and in peridomiciles with accumulated unused material (a microhabitat characteristic). These results will help to prioritise and focus control efforts by defining which peridomiciles display a potentially high abundance of Lu. longipalpis. PMID:24271040

  8. Distinct malaria parasite sporozoites reveal transcriptional changes that cause differential tissue infection competence in the mosquito vector and mammalian host.

    PubMed

    Mikolajczak, Sebastian A; Silva-Rivera, Hilda; Peng, Xinxia; Tarun, Alice S; Camargo, Nelly; Jacobs-Lorena, Vanessa; Daly, Thomas M; Bergman, Lawrence W; de la Vega, Patricia; Williams, Jack; Aly, Ahmed S I; Kappe, Stefan H I

    2008-10-01

    The malaria parasite sporozoite transmission stage develops and differentiates within parasite oocysts on the Anopheles mosquito midgut. Successful inoculation of the parasite into a mammalian host is critically dependent on the sporozoite's ability to first infect the mosquito salivary glands. Remarkable changes in tissue infection competence are observed as the sporozoites transit from the midgut oocysts to the salivary glands. Our microarray analysis shows that compared to oocyst sporozoites, salivary gland sporozoites upregulate expression of at least 124 unique genes. Conversely, oocyst sporozoites show upregulation of at least 47 genes (upregulated in oocyst sporozoites [UOS genes]) before they infect the salivary glands. Targeted gene deletion of UOS3, encoding a putative transmembrane protein with a thrombospondin repeat that localizes to the sporozoite secretory organelles, rendered oocyst sporozoites unable to infect the mosquito salivary glands but maintained the parasites' liver infection competence. This phenotype demonstrates the significance of differential UOS expression. Thus, the UIS-UOS gene classification provides a framework to elucidate the infectivity and transmission success of Plasmodium sporozoites on a whole-genome scale. Genes identified herein might represent targets for vector-based transmission blocking strategies (UOS genes), as well as strategies that prevent mammalian host infection (UIS genes).

  9. Ecological Niche Modelling Predicts Southward Expansion of Lutzomyia (Nyssomyia) flaviscutellata (Diptera: Psychodidae: Phlebotominae), Vector of Leishmania (Leishmania) amazonensis in South America, under Climate Change

    PubMed Central

    Carvalho, Bruno M.; Ready, Paul D.

    2015-01-01

    Vector borne diseases are susceptible to climate change because distributions and densities of many vectors are climate driven. The Amazon region is endemic for cutaneous leishmaniasis and is predicted to be severely impacted by climate change. Recent records suggest that the distributions of Lutzomyia (Nyssomyia) flaviscutellata and the parasite it transmits, Leishmania (Leishmania) amazonensis, are expanding southward, possibly due to climate change, and sometimes associated with new human infection cases. We define the vector’s climatic niche and explore future projections under climate change scenarios. Vector occurrence records were compiled from the literature, museum collections and Brazilian Health Departments. Six bioclimatic variables were used as predictors in six ecological niche model algorithms (BIOCLIM, DOMAIN, MaxEnt, GARP, logistic regression and Random Forest). Projections for 2050 used 17 general circulation models in two greenhouse gas representative concentration pathways: “stabilization” and “high increase”. Ensemble models and consensus maps were produced by overlapping binary predictions. Final model outputs showed good performance and significance. The use of species absence data substantially improved model performance. Currently, L. flaviscutellata is widely distributed in the Amazon region, with records in the Atlantic Forest and savannah regions of Central Brazil. Future projections indicate expansion of the climatically suitable area for the vector in both scenarios, towards higher latitudes and elevations. L. flaviscutellata is likely to find increasingly suitable conditions for its expansion into areas where human population size and density are much larger than they are in its current locations. If environmental conditions change as predicted, the range of the vector is likely to expand to southeastern and central-southern Brazil, eastern Paraguay and further into the Amazonian areas of Bolivia, Peru, Ecuador, Colombia and

  10. Winds of change: How will windstorms and forest harvesting affect C cycling in northern MN under different climate scenarios?

    NASA Astrophysics Data System (ADS)

    Lucash, M. S.; Scheller, R. M.; Gustafson, E.; Sturtevant, B.

    2013-12-01

    Forest managers struggle to manage timber resources while integrating the complex interactions that exist among disturbances with the novel conditions produced by a changing climate. To help forest managers better integrate climate change and disturbance projections into their forest management plans, we are using a forest landscape disturbance and succession model (LANDIS-II, Century extension) to project carbon sequestration in northern Minnesota under multiple climate change, management and disturbance scenarios. The model was calibrated and validated using empirical estimates of aboveground productivity and net ecosystem exchange. Our simulations suggest that windstorms will decrease tree biomass and soil organic matter and will increase dead C, resulting in an overall decrease in total C and C sink strength under the GFDL A1FI climate scenario. However the direct effects of climate change on C via altered production and heterotrophic respiration were larger than the impacts of wind. In contrast, forest harvesting will remain the dominant determinant of C dynamics under A1FI, even under management scenarios of more selective logging and longer rotation periods. Recovery from historic (late 1800s and early 1900s) disturbance - clearcut logging and wildfire - remain an important, though declining, driver of long-term C dynamics. Our research results will inform regional planning efforts and help forest managers evaluate the relative importance of disturbances (e.g. wind) and forest harvesting under a changing climate.

  11. Analysis of Unit-Level Changes in Operations with Increased SPP Wind from EPRI/LCG Balancing Study

    SciTech Connect

    Hadley, Stanton W

    2012-01-01

    Wind power development in the United States is outpacing previous estimates for many regions, particularly those with good wind resources. The pace of wind power deployment may soon outstrip regional capabilities to provide transmission and integration services to achieve the most economic power system operation. Conversely, regions such as the Southeastern United States do not have good wind resources and will have difficulty meeting proposed federal Renewable Portfolio Standards with local supply. There is a growing need to explore innovative solutions for collaborating between regions to achieve the least cost solution for meeting such a renewable energy mandate. The Department of Energy funded the project 'Integrating Midwest Wind Energy into Southeast Electricity Markets' to be led by EPRI in coordination with the main authorities for the regions: SPP, Entergy, TVA, Southern Company and OPC. EPRI utilized several subcontractors for the project including LCG, the developers of the model UPLAN. The study aims to evaluate the operating cost benefits of coordination of scheduling and balancing for Southwest Power Pool (SPP) wind transfers to Southeastern Electric Reliability Council (SERC) Balancing Authorities (BAs). The primary objective of this project is to analyze the benefits of regional cooperation for integrating mid-western wind energy into southeast electricity markets. Scenarios were defined, modeled and investigated to address production variability and uncertainty and the associated balancing of large quantities of wind power in SPP and delivery to energy markets in the southern regions of the SERC. DOE funded Oak Ridge National Laboratory to provide additional support to the project, including a review of results and any side analysis that may provide additional insight. This report is a unit-by-unit analysis of changes in operations due to the different scenarios used in the overall study. It focuses on the change in capacity factors and the number

  12. The National Assessment of Shoreline Change: a GIS compilation of vector shorelines and associated shoreline change data for the U.S. southeast Atlantic coast

    USGS Publications Warehouse

    Miller, Tara L.; Morton, Robert A.; Sallenger, Asbury H.

    2006-01-01

    The Coastal and Marine Geology Program of the U.S. Geological Survey has generated a comprehensive database of digital vector shorelines and shoreline change rates for the U.S. Southeast Atlantic Coast (Florida, Georgia, South Carolina, North Carolina). These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Beach erosion is a chronic problem along most open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of shoreline migration. There is also a critical need for shoreline change data that is consistent from one coastal region to another. One purpose of this work is to develop standard repeatable methods for mapping and analyzing shoreline movement so that periodic updates of shorelines and shoreline change rates can be made nationally that are systematic and internally consistent. This data compilation for open-ocean, sandy shorelines of the U.S. Southeast Atlantic Coast is the second in a series that already includes the Gulf of Mexico, and will eventually include the Pacific Coast, and parts of Hawaii and Alaska. Short- and long-term shoreline change evaluations are based on merging three historical shorelines with a modern shoreline derived from lidar (light detection and ranging) topographic surveys. Historical shorelines generally represent the following time periods: 1800s, 1920s-1930s, and 1970s. The most recent shoreline is derived from data collected over the period of 1997-2002. Long-term rates of change are calculated by linear regression using all four shorelines. Short-term rates of change are simple end-point rate calculations using the two most recent shorelines. Please refer to our full report on shoreline change for the U.S. Southeast Atlantic Coast at http://pubs.usgs.gov/of/2005/1401/ to get additional

  13. Operational Cloud-Motion Winds from Meteosat Infrared Images.

    NASA Astrophysics Data System (ADS)

    Schmetz, Johannes; Holmlund, Kenneth; Hoffman, Joel; Strauss, Bernard; Mason, Brian; Gaertner, Volker; Koch, Arno; van de Berg, Leo

    1993-07-01

    The displacement of clouds in successive satellite images reflects the atmospheric circulation at various scales. The main application of the satellite-derived cloud-motion vectors is their use as winds in the data analysis for numerical weather prediction. At low latitudes in particular they constitute an indispensible data source for numerical weather prediction.This paper describes the operational method of deriving cloud-motion winds (CMW) from the IR image (10.5 12.5 µm) of the European geostationary Meteostat satellites. The method is automatic, that is, the cloud tracking uses cross correlation and the height assignment is based on satellite observed brightness temperature and a forecast temperature profile. Semitransparent clouds undergo a height correction based on radiative forward calculations and simultaneous radiance observations in both the IR and water vapor (5.7 7.1 µm) channel. Cloud-motion winds are subject to various quality checks that include manual quality control as the last step. Typically about 3000 wind vectors are produced per day over four production cycles.This paper documents algorithm changes and improvements made to the operational CMWs over the last five years. The improvements are shown by long-term comparisons with both collocated radiosondes and the first guess of the forecast model of the European Centre for Medium-Range Weather Forecasts. In particular, the height assignment of a wind vector and radiance filtering techniques preceding the cloud tracking have ameliorated the errors in Meteostat winds. The slow speed bias of high-level CMWs (<400 hPa) in comparison to radiosonde winds have been reduced from about 4 to 1.3 m s1 for a mean wind speed of 24 m s1. Correspondingly, the rms vectors error of Meteosat high-level CMWs decreased from about 7.8 to 5 m s1. Medium- and low-level CMWs were also significantly improved.

  14. The future of Antarctica's surface winds simulated by a high-resolution global climate model: 2. Drivers of 21st century changes

    NASA Astrophysics Data System (ADS)

    Bintanja, R.; Severijns, C.; Haarsma, R.; Hazeleger, W.

    2014-06-01

    Antarctica's katabatic winds are among the strongest near-surface winds on Earth, and among the most consistent ones. As these winds are primarily due to the strong surface cooling, greenhouse warming of the surface may act to reduce the strength of these winds as well as their consistency. Here we use the atmospheric component of the global climate model EC-Earth in prescribed sea surface temperature (SST) simulations of the present day (2002-2006) and future (2094-2098) climates, using two model resolutions: (1) T159L62 (~100 km, 62 vertical levels), and (2) T799L91 (~20 km, 91 vertical levels) to investigate changes in Antarctica's surface winds and the reasons thereof. Circumpolar westerlies over the Southern Ocean strengthen and shift poleward because of the deepening of the circumpolar trough and the associated increase in Southern Annular Mode (SAM), especially in high resolution, causing weaker coastal easterlies. Generally, surface wind speeds over the Antarctica mainland exhibit a small decrease. According to the simulations, the temperature deficit (or inversion strength) and associated katabatic forcing exhibit only minor changes over the continent. Changes in the surface winds over Antarctica's slopes can thus be attributed mainly to changes in the synoptic forcing (large-scale pressure gradient). Hence, with modeled 21st century changes in the katabatic forcing being small, changes in zonal and meridional surface winds in and around Antarctica are largely decoupled from those over the Southern Ocean and are governed by changes in synoptic forcing and large-scale pressure gradients. As a result, these changes are largely independent on model resolution.

  15. Incorporation of wind shear terms into the governing equations of aircraft motion

    NASA Technical Reports Server (NTRS)

    Frost, W.; Bowles, R. U.

    1984-01-01

    Conventional analyses of aircraft motion in the atmosphere have neglected wind speed variability on the scales associated with many atmospheric phenomena such as thunderstorms, low-level jets, etc. These phemonena produce wind shears that have been determined as the probable cause in many recent commercial airline accidents. This paper derives the six degrees equations of motion or an aircraft incorporating the variable wind terms. The equations are presented in several coordinate systems (i.e., body coordinates, inertial coordinates, etc.). The wind shear terms, including the temporal and spatial gradients of the wind, appear differently in the various coordinate system. These terms are discussed. Also, the influence of wind shear on inputs to computing the aerodynamic coefficients such as the effects of wind velocity vector rotation on relative angular rates of rotation and on the time rate of change of angles of attack and side slip are addressed.

  16. Response of the Earth's Magnetosphere to Changes in the Solar Wind

    NASA Technical Reports Server (NTRS)

    McPherron, Robert L.; Weygand, James M.; Hsu, Tung-Shin

    2007-01-01

    The solar wind couples to the magnetosphere via dynamic pressure and electric field. Pressure establishes the size and shape of the system, while the electric field transfers energy, mass, and momentum to the magnetosphere. When the interplanetary magnetic field (IMF) is antiparallel to the dayside magnetic field, magnetic reconnection connects the IMF to the dipole field. Solar wind transport of the newly opened field lines to the nightside creates an internal convection system. These open field lines must ultimately be closed by reconnection on the nightside. For many decades, it was thought that a magnetospheric substorm was the process for accomplishing this and that all magnetic activity was a consequence of substorms. It is now recognized that there are a variety of modes of response of the magnetosphere to the solar wind. In this paper, we briefly describe these modes and the conditions under which they occur. They include substorms, pseudo-breakups, poleward boundary intensifications (PBI), steady magnetospheric convection (SMC), sawtooth injection events, magnetic storms, high-intensity long-duration continuous AE activities (HILDCAAs), and storm-time activations. There are numerous explanations for these different phenomena, some of which do not involve magnetic reconnection. However, we speculate that it is possible to interpret each mode in terms of differences in the way magnetic reconnection occurs on the nightside.

  17. Phase-Dependent Changes in O VI and Other Stellar Wind Lines in SMC X-1

    NASA Astrophysics Data System (ADS)

    Sonneborn, G.; Iping, R. C.; Massa, D. L.; Gruber, D.; Schlegel, E. M.; Hutchings, J. B.

    2004-12-01

    The accretion-powered high-mass X-ray binary SMC X-1/Sk 160 was observed for one complete orbit (3.89 days) with the Far Ultraviolet Spectroscopic Explorer (FUSE) to study how the strong X-ray source modulates the stellar wind of the B0 I primary. The observations were obtained primarily on 2003 July 19-23, with additional observations on 2003 Oct 27 and 2004 Aug 23 filling some phase gaps and duplicating others. Interstellar lines of molecular hydrogen and O VI 1032 from foreground Milky Way and SMC gas were modelled and used to correct the observed stellar O VI 1032 P-Cygni line profiles. The O VI absorption shows that the wind is highly asymmetry around the orbit. The line is at maximum strength during the eclipse of the pulsar (phase 0.0), with a total column density of N(O VI) = 7E17 cm-2. The O VI line virtually disappears near phase 0.4. The terminal velocity (700 km/s) drops to near zero at phase 0.3-0.4. These results are qualitatively consistent with 3D-hydrodynamic models of the disrupted stellar wind of SMC X-1 (Blondin and Woo 1995, ApJ, 445, 889). Archival HST/STIS spectra of SMC X-1 obtained in 2000 and 2001 show that the N V 1238-42 and C IV 1548-50 stellar wind features have phase dependences similar to that seen in O VI. The line profile variations do not appear to be correlated with X-ray high or low states of the 60-day super-orbital period. Other stellar wind lines in the FUSE spectrum of SMC X-1 (S IV 1073, P V 1117, Si IV 1122, C III 1176) show much smaller orbital modulation effects than are seen in O VI. These lines are present at approximately the same strength at all phases. This work was supported in part by NASA grant NNG04GK79G to Catholic University of America for FUSE GI program D175.

  18. Off shore wind farms change the benthic pelagic coupling in the Belgian Part of the North Sea

    NASA Astrophysics Data System (ADS)

    Vanaverbeke, Jan; Coates, Delphine; Braeckman, Ulrike; Soetaert, Karline; Moens, Tom

    2016-04-01

    Since Europe enforced renewable energy target figures upon its member states through the implementation of two main European Directives 11 2001/77/EC and 2009/28/EC, the development of offshore wind farms (OWF) has accelerated. Belgium installed OWFs on sandbanks, characterized by permeable sediments, low in organic matter content and a species-poor macrofaunal community with species occurring in low densities. A detailed monitoring campaign in the immediate vicinity of a wind turbine (1-200m), revealed a significant decrease in median grain size and permeability, coinciding with a 6-fold increase in organic matter content. The observed fining of the sediment is explained by an altered benthic-pelagic coupling in the area. The wind turbines are colonized by an abundant fouling community producing high amounts of detritus and faeces, a continuous additional source of organic matter. The changes in sediment composition, and the availability of additional organic matter resulted in drastic increase in macrofaunal densities (from 1390 ind m-2 to 18600 ind m-2), and a change from a species-poor community to a species-rich community dominated by the ecosystem engineer Lanice conchilega. Large densities of L. conchilega, as observed in our samples, are known to trap fine material from the water column, which can result in a further decrease of sediment permeability in the vicinity of the wind turbines. A preliminary experiment, where permeable sediments were subjected to artificial fining, showed a decreased penetration depth of advective water currents and a reduced trapping of diatoms by the sediment in finer sediments. Additionally, sediment community oxygen consumption rates, and efflux of NH4+ from the sediment, measured after a simulated phytoplankton bloom, decreased significantly when sediment permeability was reduced. We hypothesize that the combination of the altered macrofaunal community composition, together with the changes in the physical properties of the

  19. The influence of changes in wind patterns on the areal extension of surface cyanobacterial blooms in a large shallow lake in China.

    PubMed

    Wu, Tingfeng; Qin, Boqiang; Brookes, Justin D; Shi, Kun; Zhu, Guangwei; Zhu, Mengyuan; Yan, Wenming; Wang, Zhen

    2015-06-15

    It has been hypothesized that climate change will induce the areal extension of cyanobacterial blooms. However, this hypothesis lacks field-based observation. In the present study both long-term historical data and short-term field measurement were used to identify the importance of changes in wind patterns on the cyanobacterial bloom in Lake Taihu (China), a large, shallow, eutrophic lake located in a subtropical zone. The cyanobacterial bloom mainly composed of Microcystis spp. recurred frequently throughout the year. The regression analysis of multi-year satellite image data extracted by the Floating Algae Index revealed that both the annual mean monthly maximum cyanobacterial bloom area (MMCBA) increased year by year from 2000 to 2011, while the contemporaneous cyanobacterial biomass showed no significant change. However, the correlation analysis shows that MMCBA was negatively correlated with wind speed. Our short-term field measurements indicated that the influence of wind on surface cyanobacterial blooms is that the Chlorophyll-a (Chla) concentration is fully mixing throughout the water column when the wind speed exceed 7 m s(-1). At lower wind speeds, there was vertical stratification of Chla with high surface concentrations and an increase in bloom area. The regression analysis of wind speed indicates that the climate has changed over the last decade. Lake Taihu has become increasingly calm, with the decrease of strong wind frequency between 2000 and 2011, corresponding to the increase in the MMCBA over time. Therefore, we conclude that changes in wind patterns related to climate change have favored the increase of cyanobacterial blooms in Lake Taihu.

  20. Short-Term Wind Power Forecasts using Doppler Lidar

    NASA Astrophysics Data System (ADS)

    Magerman, Beth

    With a ground-based Doppler lidar on the upwind side of a wind farm in the Tehachapi Pass of California, radial wind velocity measurements were collected for repeating sector sweeps, scanning up to 10 kilometers away. This region consisted of complex terrain, with the scans made between mountains. The dataset was utilized for techniques being studied for short-term forecasting of wind power by correlating changes in energy content and of turbulence intensity by tracking spatial variance, in the wind ahead of a wind farm. A ramp event was also captured and its propagation was tracked. Orthogonal horizontal wind vectors were retrieved from the radial velocity using a sector Velocity Azimuth Display method. Streamlines were plotted to determine the potential sites for a correlation of upstream wind speed with wind speed at downstream locations near the wind farm. A "virtual wind turbine" was "placed" in locations along the streamline by using the time-series velocity data at the location as the input to a modeled wind turbine, to determine the extractable energy content at that location. The relationship between this time-dependent energy content upstream and near the wind farm was studied. By correlating the energy content with each upstream location based on a time shift estimated according to advection at the mean wind speed, several fits were evaluated. A prediction of the downstream energy content was produced by shifting the power output in time and applying the best-fit function. This method made predictions of the power near the wind farm several minutes in advance. Predictions were also made up to an hour in advance for a large ramp event. The Magnitude Absolute Error and Standard Deviation are presented for the predictions based on each selected upstream location.

  1. The impact of climate change on the global coastal low-level wind jets: EC-EARTH simulations

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    Coastal low-level jets (CLLJ) are low tropospheric coast-parallel wind features, confined to the marine atmospheric boundary layer, which lay on the east flank of the semi-permanent sub-tropical high-pressure systems, in the mid-latitudes, along equator-ward eastern boundary currents. Coastal jets are of utmost relevance to the regional climate, through their impact on the along coast sea surface temperature, driving the upwelling of cold deep nutrient-rich waters, and by having a decisive impact on the aridity of the mid-latitude western coastal areas. Here the impact of a warmer climate in the CLLJ climate is investigated, through a 2-member ensemble of EC-Earth CMIP5 simulations of future climate, following the RCP8.5 greenhouse gases emissions scenario. Besides the projected changes of the CLLJ, towards the end of the 21st century, the future characteristics of the coastal jets are also presented. No common feature of projected changes in the seven identified CLLJ areas was identified. The Iberian Peninsula and the Oman coastal jets are the ones that presented the highest differences, compared to present climate: highest projected increases in frequency of occurrence, as well as highest projected increases in jet strength (wind speed at the jet height) and jet height. This study presents a step forward towards a larger ensemble of CLLJ projections, required to better assess robustness and uncertainty of potential future climate change.

  2. Investigation of Wind Speed Persistence Over Marmara Region

    NASA Astrophysics Data System (ADS)

    Özgür, Evren; Koçak, Kasım

    2016-04-01

    Persistence is a measure of continuity of a variable over a period of time at any location. This definition implies that wind speed persistence means a positive serial correlation in a time series. In literature, there are numerous methods for measuring wind speed persistence. In this study, wind speed persistence were obtained for 19 stations located in Marmara Region by using two different methods. Daily wind speed data, taken from Turkish State Meteorological Service, were used in the study. The observation period was taken to be 1965-2014 for all stations. The methods used in the study are directional statistical method and wind speed duration curves approach. In directional statistical method, individual dates of winds are defined as directional variables; then, directional mean and variance are calculated. Wind dates are being converted to angular values and these days are being considered as a unit vector which has direction θ. In polar coordinate, the measures of directional mean and variance have been expressed as a vector with direction θmean and magnitude r. The r value can be considered as a measure of persistence. The wind speed duration curve is simply the cumulative distribution function of the wind speed in a certain period of time. In other words, it is the graphical representation of wind speed and percentage of exceedence time for a predefined threshold wind speed value in the same graphic. As a threshold wind speed, lower quartile (q0.25) value of ranked wind speed data were selected. In application, total time period was divided into five subperiods and changes of persistence in wind speeds as far as subperiods were presented. Persistence can be used in different kinds of study areas such as control of forest fires, dispersion of air pollutants, calculation of wind energy potential, ventilation of a city, etc. The results of this analysis showed that the proposed methods can be used as an alternative approach to determine whether a given time

  3. Coherent Doppler Lidar for Boundary Layer Studies and Wind Energy

    NASA Astrophysics Data System (ADS)

    Choukulkar, Aditya

    This thesis outlines the development of a vector retrieval technique, based on data assimilation, for a coherent Doppler LIDAR (Light Detection and Ranging). A detailed analysis of the Optimal Interpolation (OI) technique for vector retrieval is presented. Through several modifications to the OI technique, it is shown that the modified technique results in significant improvement in velocity retrieval accuracy. These modifications include changes to innovation covariance portioning, covariance binning, and analysis increment calculation. It is observed that the modified technique is able to make retrievals with better accuracy, preserves local information better, and compares well with tower measurements. In order to study the error of representativeness and vector retrieval error, a lidar simulator was constructed. Using the lidar simulator a thorough sensitivity analysis of the lidar measurement process and vector retrieval is carried out. The error of representativeness as a function of scales of motion and sensitivity of vector retrieval to look angle is quantified. Using the modified OI technique, study of nocturnal flow in Owens' Valley, CA was carried out to identify and understand uncharacteristic events on the night of March 27th 2006. Observations from 1030 UTC to 1230 UTC (0230 hr local time to 0430 hr local time) on March 27 2006 are presented. Lidar observations show complex and uncharacteristic flows such as sudden bursts of westerly cross-valley wind mixing with the dominant up-valley wind. Model results from Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS RTM) and other in-situ instrumentations are used to corroborate and complement these observations. The modified OI technique is used to identify uncharacteristic and extreme flow events at a wind development site. Estimates of turbulence and shear from this technique are compared to tower measurements. A formulation for equivalent wind speed in the presence of variations in wind speed

  4. Ionospheric traveling convection vortices observed near the polar cleft - A triggered response to sudden changes in the solar wind

    NASA Technical Reports Server (NTRS)

    Friis-Christensen, E.; Vennerstrom, S.; Mchenry, M. A.; Clauer, C. R.

    1988-01-01

    Analysis of 20-second resolution magnetometer data from an array of temporary stations operated around Sondre Stromfjord, Greenland, during the summer of 1986 shows the signatures of localized ionospheric traveling convection vortices. An example of an isolated event of this kind observed near 08 local time is presented in detail. This event consists of a twin vortex pattern of convection consistent with the presence of two field-aligned current filaments separated by about 600 km in the east-west direction. This system of currents is observed to move westward (tailward) past the array of stations at about 4 km/sec. The event is associated with relative quiet time ionospheric convection and occurs during an interval of northward IMF. It is, however, associated with a large fluctuation in both the Z and Y components of the IMF and with a large sudden decrease in the solar wind number density. The propagation of the system is inconsistent with existing models of FTE current systems, but nevertheless appears to be related to a readjustment of the magnetopause boundary to a sudden change in the solar wind dynamic pressure and/or to a change in reconnection brought about by a sudden reorientation of the IMF.

  5. The impact of climate change on the geographical distribution of two vectors of Chagas disease: implications for the force of infection

    PubMed Central

    Medone, Paula; Ceccarelli, Soledad; Parham, Paul E.; Figuera, Andreína; Rabinovich, Jorge E.

    2015-01-01

    Chagas disease, caused by the parasite Trypanosoma cruzi, is the most important vector-borne disease in Latin America. The vectors are insects belonging to the Triatominae (Hemiptera, Reduviidae), and are widely distributed in the Americas. Here, we assess the implications of climatic projections for 2050 on the geographical footprint of two of the main Chagas disease vectors: Rhodnius prolixus (tropical species) and Triatoma infestans (temperate species). We estimated the epidemiological implications of current to future transitions in the climatic niche in terms of changes in the force of infection (FOI) on the rural population of two countries: Venezuela (tropical) and Argentina (temperate). The climatic projections for 2050 showed heterogeneous impact on the climatic niches of both vector species, with a decreasing trend of suitability of areas that are currently at high-to-moderate transmission risk. Consequently, climatic projections affected differently the FOI for Chagas disease in Venezuela and Argentina. Despite the heterogeneous results, our main conclusions point out a decreasing trend in the number of new cases of Tr. cruzi human infections per year between current and future conditions using a climatic niche approach. PMID:25688019

  6. The impact of climate change on the geographical distribution of two vectors of Chagas disease: implications for the force of infection.

    PubMed

    Medone, Paula; Ceccarelli, Soledad; Parham, Paul E; Figuera, Andreína; Rabinovich, Jorge E

    2015-04-05

    Chagas disease, caused by the parasite Trypanosoma cruzi, is the most important vector-borne disease in Latin America. The vectors are insects belonging to the Triatominae (Hemiptera, Reduviidae), and are widely distributed in the Americas. Here, we assess the implications of climatic projections for 2050 on the geographical footprint of two of the main Chagas disease vectors: Rhodnius prolixus (tropical species) and Triatoma infestans (temperate species). We estimated the epidemiological implications of current to future transitions in the climatic niche in terms of changes in the force of infection (FOI) on the rural population of two countries: Venezuela (tropical) and Argentina (temperate). The climatic projections for 2050 showed heterogeneous impact on the climatic niches of both vector species, with a decreasing trend of suitability of areas that are currently at high-to-moderate transmission risk. Consequently, climatic projections affected differently the FOI for Chagas disease in Venezuela and Argentina. Despite the heterogeneous results, our main conclusions point out a decreasing trend in the number of new cases of Tr. cruzi human infections per year between current and future conditions using a climatic niche approach.

  7. The effects of changing winds and temperatures on the oceanography of the Ross Sea in the 21st century

    NASA Astrophysics Data System (ADS)

    Smith, Walker O.; Dinniman, Michael S.; Hofmann, Eileen E.; Klinck, John M.

    2014-03-01

    The Ross Sea is critically important in regulating Antarctic sea ice and is biologically productive, which makes changes in the region's physical environment of global concern. We examined the effects of projected changes in atmospheric temperatures and winds on aspects of the ocean circulation likely important to primary production using a high-resolution sea ice-ocean-ice shelf model of the Ross Sea. The modeled summer sea-ice concentrations decreased by 56% by 2050 and 78% by 2100. The duration of shallow mixed layers over the continental shelf increased by 8.5 and 19.2 days in 2050 and 2100, and the mean summer mixed layer depths decreased by 12 and 44%. These results suggest that the annual phytoplankton production in the future will increase and become more diatomaceous. Other components of the Ross Sea food web will likely be severely disrupted, creating significant but unpredictable impacts on the ocean's most pristine ecosystem.

  8. WindSat Radio-Frequency Interference Signature and Its Identification Over Land and Ocean

    DTIC Science & Technology

    2006-03-01

    differences can change significantly with ocean surface conditions (wind speed and direction) and atmospheric events (water vapor, cloud , and...vector is given by RI RI RI RI RI RI RI RI RI , which represents a data cloud in a nine-dimensional space . After the principal component decomposition...Ocean RFI detections for X-band horizontal polarization using the spectral difference method. ocean surface wind, cloud , and rain variations. We could

  9. Wind turbine

    DOEpatents

    Cheney, Jr., Marvin C.

    1982-01-01

    A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.

  10. Fractional Factorial Experiment Designs to Minimize Configuration Changes in Wind Tunnel Testing

    NASA Technical Reports Server (NTRS)

    DeLoach, Richard; Cler, Daniel L.; Graham, Albert B.

    2002-01-01

    This paper serves as a tutorial to introduce the wind tunnel research community to configuration experiment designs that can satisfy resource constraints in a configuration study involving several variables, without arbitrarily eliminating any of them from the experiment initially. The special case of a configuration study featuring variables at two levels is examined in detail. This is the type of study in which each configuration variable has two natural states - 'on or off', 'deployed or not deployed', 'low or high', and so forth. The basic principles are illustrated by results obtained in configuration studies conducted in the Langley National Transonic Facility and in the ViGYAN Low Speed Tunnel in Hampton, Virginia. The crucial role of interactions among configuration variables is highlighted with an illustration of difficulties that can be encountered when they are not properly taken into account.

  11. Decades-long changes of the interstellar wind through our solar system.

    PubMed

    Frisch, P C; Bzowski, M; Livadiotis, G; McComas, D J; Moebius, E; Mueller, H-R; Pryor, W R; Schwadron, N A; Sokół, J M; Vallerga, J V; Ajello, J M

    2013-09-06

    The journey of the Sun through the dynamically active local interstellar medium creates an evolving heliosphere environment. This motion drives a wind of interstellar material through the heliosphere that has been measured with Earth-orbiting and interplanetary spacecraft for 40 years. Recent results obtained by NASA's Interstellar Boundary Explorer mission during 2009-2010 suggest that neutral interstellar atoms flow into the solar system from a different direction than found previously. These prior measurements represent data collected from Ulysses and other spacecraft during 1992-2002 and a variety of older measurements acquired during 1972-1978. Consideration of all data types and their published results and uncertainties, over the three epochs of observations, indicates that the trend for the interstellar flow ecliptic longitude to increase linearly with time is statistically significant.

  12. Changing Climate and Wind Patterns Revealed in Indiana's Fair Oaks Dunes

    NASA Astrophysics Data System (ADS)

    Kilibarda, Z.

    2004-12-01

    Fair Oak Dunes (FOD) cover over 1100 square miles in north-central Indiana. Careful study of dune morphology reveals three types of dunes in regards to their size. The first order forms are compound parabolic dunes that reach over five miles in length and have the apex of parabola pointing in a southwesterly direction. The spacing between these dunes is three to five miles. The second order dune ridges are compound parabolic dunes that range in size from one to three miles in length with spacing of about one mile between the ridges. Both, the second order and the third order dunes have the apex of parabola pointing in northeasterly direction, opposite of the first order dunes. The third order dune ridges are simple parabolic dunes that reach up to half mile in length and are 25 to 30 feet tall in western part to over 45 feet in the eastern part of the FOD. All dunes are fixed by lush vegetation. Preliminary grain size analyses indicate that north part of FOD has coarser sand (0.283 mm) than southern part (0.197 mm), while eastern part (0.271 mm) is coarser than the western part (0.223 mm). This grain size distribution is in accordance with initial interpretation of dune morphology. Strong northeasterly winds associated with anticyclone were prevalent in early dune formation about 14,000 years ago near the end of last glacial. The finest particles were blown south and southwest from the source area which was north and east of the present dunes. Cyclonic southwesterly winds become dominant in Holocene and caused a reworking of the original large dunes into smaller forms as well as removal of some of the finest particles back to the original source to the northeast. Limited vertical dune profiles indicate that below the 5 feet of bioturbated surface layer are alternating light layers (3 to 5 inch thick) and dark laminae (1-2 inches thick). Dark laminae consist of quartz grains with `hairy' surfaces covered with reddish iron oxides or clays. They contain twice as much

  13. Impact of land use change on wind erosion and dust emission: scenarios from the central US

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There will be significant changes in land cover and land use throughout the central United States in the coming years, particularly as a result of climate change, changes in US rangeland/farm policy, and increasing exploitation of land-intensive sustainable energy sources. The purpose of this study ...

  14. Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis

    PubMed Central

    Elaagip, Arwa H.; Kenawy, Mohamed A.; Ayres, Constância F. J.; Peterson, A. Townsend; Soliman, Doaa E.

    2016-01-01

    Rapid emergence of most vector-borne diseases (VBDs) may be associated with range expansion of vector populations. Culex quinquefasciatus Say 1823 is a potential vector of West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. We estimated the potential distribution of Cx. quinquefasciatus under both current and future climate conditions. The present potential distribution of Cx. quinquefasciatus showed high suitability across low-latitude parts of the world, reflecting the current distribution of the species. Suitable conditions were identified also in narrow zones of North Africa and Western Europe. Model transfers to future conditions showed a potential distribution similar to that under present-day conditions, although with higher suitability in southern Australia. Highest stability with changing climate was between 30°S and 30°N. The areas present high agreement among diverse climate models as regards distributional potential in the future, but differed in anticipating potential for distribution in North and Central Africa, southern Asia, central USA, and southeastern Europe. Highest disparity in model predictions across representative concentration pathways (RCPs) was in Saudi Arabia and Europe. The model predictions allow anticipation of changing distributional potential of the species in coming decades. PMID:27695107

  15. Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis.

    PubMed

    Samy, Abdallah M; Elaagip, Arwa H; Kenawy, Mohamed A; Ayres, Constância F J; Peterson, A Townsend; Soliman, Doaa E

    2016-01-01

    Rapid emergence of most vector-borne diseases (VBDs) may be associated with range expansion of vector populations. Culex quinquefasciatus Say 1823 is a potential vector of West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. We estimated the potential distribution of Cx. quinquefasciatus under both current and future climate conditions. The present potential distribution of Cx. quinquefasciatus showed high suitability across low-latitude parts of the world, reflecting the current distribution of the species. Suitable conditions were identified also in narrow zones of North Africa and Western Europe. Model transfers to future conditions showed a potential distribution similar to that under present-day conditions, although with higher suitability in southern Australia. Highest stability with changing climate was between 30°S and 30°N. The areas present high agreement among diverse climate models as regards distributional potential in the future, but differed in anticipating potential for distribution in North and Central Africa, southern Asia, central USA, and southeastern Europe. Highest disparity in model predictions across representative concentration pathways (RCPs) was in Saudi Arabia and Europe. The model predictions allow anticipation of changing distributional potential of the species in coming decades.

  16. Three Dimensional Dynamic Model Based Wind Field Reconstruction from Lidar Data

    NASA Astrophysics Data System (ADS)

    Raach, Steffen; Schlipf, David; Haizmann, Florian; Cheng, Po Wen

    2014-06-01

    Using the inflowing horizontal and vertical wind shears for individual pitch controller is a promising method if blade bending measurements are not available. Due to the limited information provided by a lidar system the reconstruction of shears in real-time is a challenging task especially for the horizontal shear in the presence of changing wind direction. The internal model principle has shown to be a promising approach to estimate the shears and directions in 10 minutes averages with real measurement data. The static model based wind vector field reconstruction is extended in this work taking into account a dynamic reconstruction model based on Taylor's Frozen Turbulence Hypothesis. The presented method provides time series over several seconds of the wind speed, shears and direction, which can be directly used in advanced optimal preview control. Therefore, this work is an important step towards the application of preview individual blade pitch control under realistic wind conditions. The method is tested using a turbulent wind field and a detailed lidar simulator. For the simulation, the turbulent wind field structure is flowing towards the lidar system and is continuously misaligned with respect to the horizontal axis of the wind turbine. Taylor's Frozen Turbulence Hypothesis is taken into account to model the wind evolution. For the reconstruction, the structure is discretized into several stages where each stage is reduced to an effective wind speed, superposed with a linear horizontal and vertical wind shear. Previous lidar measurements are shifted using again Taylor's Hypothesis. The wind field reconstruction problem is then formulated as a nonlinear optimization problem, which minimizes the residual between the assumed wind model and the lidar measurements to obtain the misalignment angle and the effective wind speed and the wind shears for each stage. This method shows good results in reconstructing the wind characteristics of a three dimensional

  17. PULSED ALFVEN WAVES IN THE SOLAR WIND

    SciTech Connect

    Gosling, J. T.; Tian, H.; Phan, T. D.

    2011-08-20

    Using 3 s plasma and magnetic field data from the Wind spacecraft located in the solar wind well upstream from Earth, we report observations of isolated, pulse-like Alfvenic disturbances in the solar wind. These isolated events are characterized by roughly plane-polarized rotations in the solar wind magnetic field and velocity vectors away from the directions of the underlying field and velocity and then back again. They pass over Wind on timescales ranging from seconds to several minutes. These isolated, pulsed Alfven waves are pervasive; we have identified 175 such events over the full range of solar wind speeds (320-550 km s{sup -1}) observed in a randomly chosen 10 day interval. The large majority of these events are propagating away from the Sun in the solar wind rest frame. Maximum field rotations in the interval studied ranged from 6 Degree-Sign to 109 Degree-Sign . Similar to most Alfvenic fluctuations in the solar wind at 1 AU, the observed changes in velocity are typically less than that predicted for pure Alfven waves (Alfvenicity ranged from 0.28 to 0.93). Most of the events are associated with small enhancements or depressions in magnetic field strength and small changes in proton number density and/or temperature. The pulse-like and roughly symmetric nature of the magnetic field and velocity rotations in these events suggests that these Alfvenic disturbances are not evolving when observed. They thus appear to be, and probably are, solitary waves. It is presently uncertain how these waves originate, although they may evolve out of Alfvenic turbulence.

  18. The Pollination of Trimenia moorei (Trimeniaceae): Floral Volatiles, Insect/Wind Pollen Vectors and Stigmatic Self-incompatibility in a Basal Angiosperm

    PubMed Central

    BERNHARDT, PETER; SAGE, TAMMY; WESTON, PETER; AZUMA, HIROSHI; LAM, MATHEW; THIEN, LEONARD B.; BRUHL, JEREMY

    2003-01-01

    Trimenia moorei (Oliv.) Philipson is an andromonoecious liane with >0·40 of the total flower buds maturing as bisexual flowers. Male and bisexual flowers are strongly scented with pollen, anther sacs and receptacle scars testing positively for volatile emissions. Scent analyses detect over 20 components. The major fatty acid derivative is 8-heptadecene, and 2-phenylethanol dominates the benzenoids. While hover-flies in the genera Melangyna and Triglyphus contact the stigma with their probosces, the stigma secretes no free-flowing, edible fluids. Copious pollen is the only edible reward consumed by hover-flies (Syprhidae), sawflies (Pergidae) and bees in the families Apidae, Colletidae and Halictidae. All these insects carried pollen of T. moorei on their heads, legs and thoraces and female bees in the genera Apis, Exoneura, Leioproctus and Lasioglossum stored pollen on their hind legs. Pollen traps also indicate that pollen is shed directly into the air, permitting wind pollination. When bisexual flower buds are bagged (isolated from insect foragers) on the liane then subjected to a series of hand-pollination experiments after perianth segments open, the structural analyses of pollen–carpel interactions indicate that T. moorei has a trichome-rich dry-type stigma with an early-acting self-incompatibility (SI) system. Bicellular pollen grains deposited on stigmas belonging to the same plant germinate but fail to penetrate intercellular spaces, while grains deposited following cross-pollination reach the ovule within 24 h. Fluorescence analyses of 76 carpels collected at random from unbagged (open-pollinated) flowers on five plants indicates that at least 64 % of carpels are cross-pollinated in situ. Trimenia moorei is the first species within the ANITA group, and second within reilictual-basal angiosperm lineages, to exhibit stigmatic SI in combination with dry-type stigma and bicellular pollen, a condition once considered to be atypical for angiosperms as a

  19. Planetary period oscillations in Saturn's magnetosphere: Examining the relationship between abrupt changes in behavior and solar wind-induced magnetospheric compressions and expansions

    NASA Astrophysics Data System (ADS)

    Provan, G.; Tao, C.; Cowley, S. W. H.; Dougherty, M. K.; Coates, A. J.

    2015-11-01

    We examine planetary period oscillations (PPOs) observed in Saturn's magnetospheric magnetic field data from the time of Saturn's equinox in 2009. In particular, we focus on the time period commencing February 2011, when the oscillations started to display sudden and unexpected changes in behavior at ~100-200 day intervals. These were characterized by large simultaneous changes in the amplitude of the northern and southern PPO systems, together with small changes in period and jumps in phase. Nine significant abrupt changes have been observed in the postequinox interval to date, commencing as the Sun started to emerge from a long extended solar minimum. We perform a statistical study to determine whether these modulations in PPO behavior were associated with changes in the solar and/or upstream solar wind conditions. We report that the upstream solar wind conditions show elevated values of solar wind dynamic pressure and density around the time of PPO behavioral transitions, as opposed to before and after these times. We suggest that abrupt changes in PPO behavior may be related to significant changes in the size of the Saturnian magnetosphere in response to varying solar wind conditions.

  20. Medical Education in the Anatomical Sciences: The Winds of Change Continue to Blow

    ERIC Educational Resources Information Center

    Drake, Richard L.; McBride, Jennifer M.; Lachman, Nirusha; Pawlina, Wojciech

    2009-01-01

    At most institutions, education in the anatomical sciences has undergone several changes over the last decade. To identify the changes that have occurred in gross anatomy, microscopic anatomy, neuroscience/neuroanatomy, and embryology courses, directors of these courses were asked to respond to a survey with questions pertaining to total course…

  1. Wind turbine apparatus

    SciTech Connect

    Storm, J.

    1985-10-08

    Wind turbine apparatus includes a plurality of sail elements secured to a circular frame rotatable in response to wind reacting with the sail elements and a control system for the sail elements includes a weight having cables extending from the weight to the sail elements. Movement of the weight in response to wind velocity results in a change in the sail elements exposed to the wind.

  2. Hot gas ingestion test results of a two-poster vectored thrust concept with flow visualization in the NASA Lewis 9- x 15-foot low speed wind tunnel

    NASA Technical Reports Server (NTRS)

    Johns, Albert L.; Neiner, George; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.; Strock, Thomas W.

    1990-01-01

    A 9.2 percent scale Short Takeoff and Vertical Landing (STOVL) hot gas ingestion model was designed and built by McDonnell Douglas Corporation (MCAIR) and tested in the Lewis Research Center 9 x 15 foot Low Speed Wind Tunnel (LSWT). Hot gas ingestion, the entrainment of heated engine exhaust into the inlet flow field, is a key development issure for advanced short takeoff and vertical landing aircraft. Flow visualization from the Phase 1 test program, which evaluated the hot ingestion phenomena and control techniques, is covered. The Phase 2 test program evaluated the hot gas ingestion phenomena at higher temperatures and used a laser sheet to investigate the flow field. Hot gas ingestion levels were measured for the several forward nozzle splay configurations and with flow control/life improvement devices (LIDs) which reduced the hot gas ingestion. The model support system had four degrees of freedom - pitch, roll, yaw, and vertical height variation. The model support system also provided heated high-pressure air for nozzle flow and a suction system exhaust for inlet flow. The test was conducted at full scale nozzle pressure ratios and inlet Mach numbers. Test and data analysis results from Phase 2 and flow visualization from both Phase 1 and 2 are documented. A description of the model and facility modifications is also provided. Headwind velocity was varied from 10 to 23 kn. Results are presented over a range of nozzle pressure ratios at a 10 kn headwind velocity. The Phase 2 program was conducted at exhaust nozzle temperatures up to 1460 R and utilized a sheet laser system for flow visualization of the model flow field in and out of ground effects. The results reported are for nozzle exhaust temperatures up to 1160 R. These results will contain the compressor face pressure and temperature distortions, the total pressure recovery, the inlet temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane contours

  3. Changes in solar wind-magnetosphere coupling with solar cycle, season, and time relative to stream interfaces

    NASA Astrophysics Data System (ADS)

    McPherron, Robert L.; Baker, Daniel N.; Pulkkinen, T. I.; Hsu, T.-S.; Kissinger, J.; Chu, X.

    2013-07-01

    Geomagnetic activity depends on a variety of factors including solar zenith angle, solar UV, strength of the interplanetary magnetic field, speed and density of the solar wind, orientation of the Earth’s dipole, distance of the Earth from Sun, occurrence of CMEs and CIRs, and possibly other parameters. We have investigated some of these using state-dependant linear prediction filters. For a given state a prediction filter transforms a coupling function such as rectified solar wind electric field (VBs) to an output like the auroral electrojet index (AL). The area of this filter calculated from the sum of the filter coefficients measures the strength of the coupling. When the input and output are steady for a time longer than the duration of the filter the ratio of output to input is equal to this area. We find coupling strength defined in this way for Es=VBs to AL (and AU) is weakest at solar maximum and strongest at solar minimum. AL coupling displays a semiannual variation being weakest at the solstices and strongest at the equinoxes. AU coupling has only an annual variation being strongest at summer solstice. AL and AU coupling also vary with time relative to a stream interface. Es coupling is weaker after the interface, but ULF coupling is stronger. Total prediction efficiency remains about constant at the interface. The change in coupling strength with the solar cycle can be explained as an effect of more frequent saturation of the polar cap potential causing a smaller ratio of AL to Es. Stronger AL coupling at the equinoxes possibly indicates some process that makes magnetic reconnection less efficient when the dipole axis is tilted along the Earth-Sun line. Strong AU coupling at summer solstice is likely due to high conductivity in northern summer. Coupling changes at a stream interface are correlated with the presence of strong wave activity in ground and satellite measurements and may be an artifact of the method by which solar wind data are propagated.

  4. Multifractal Behavior of Wind Speed and Wind Direction

    NASA Astrophysics Data System (ADS)

    Weerasinghe, R. M.; Pannila, A. S.; Jayananda, M. K.; Sonnadara, D. U. J.

    2016-01-01

    In this paper, an analysis of temporal variation of wind speed and wind direction recorded at 10 min intervals are presented. The measurements were carried out at Hambanthota, a site located in the southern coastal belt of Sri Lanka which has a high potential for wind power generation. The multifractal detrended fluctuation analysis was used to analyze the temporal scaling properties of wind speeds and wind directions. The analysis was carried out for seasonal variation of wind speed and wind direction. It was observed that the scaling behavior of wind speed in Hambanthota is similar to the scaling behavior observed in previous studies which were carried out in other parts of the world. The seasonal wind and wind direction change exhibits different scaling behavior. No difference in scaling behavior was observed with heights. The degree of multifractality is high for wind direction when compared with wind speed for each season.

  5. The Winds of Change: Thomas Kuhn and the Revolution in the Teaching of Writing.

    ERIC Educational Resources Information Center

    Hairston, Maxine

    1982-01-01

    Uses Thomas Kuhn's hypothesis on paradigm shifts--changes in a discipline from established models to newer ones--to examine the developing shift in writing instruction from the product-oriented to the process-oriented model. (RL)

  6. Three-Dimensional Wind Profiling of Offshore Wind Energy Areas With Airborne Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Koch, Grady J.; Beyon, Jeffrey Y.; Cowen, Larry J.; Kavaya, Michael J.; Grant, Michael S.

    2014-01-01

    A technique has been developed for imaging the wind field over offshore areas being considered for wind farming. This is accomplished with an eye-safe 2-micrometer wavelength coherent Doppler lidar installed in an aircraft. By raster scanning the aircraft over the wind energy area (WEA), a three-dimensional map of the wind vector can be made. This technique was evaluated in 11 flights over the Virginia and Maryland offshore WEAs. Heights above the ocean surface planned for wind turbines are shown to be within the marine boundary layer, and the wind vector is seen to show variation across the geographical area of interest at turbine heights.

  7. Three-dimensional wind profiling of offshore wind energy areas with airborne Doppler lidar

    NASA Astrophysics Data System (ADS)

    Koch, Grady J.; Beyon, Jeffrey Y.; Cowen, Larry J.; Kavaya, Michael J.; Grant, Michael S.

    2014-01-01

    A technique has been developed for imaging the wind field over offshore areas being considered for wind farming. This is accomplished with an eye-safe 2-μm wavelength coherent Doppler lidar installed in an aircraft. By raster scanning the aircraft over the wind energy area (WEA), a three-dimensional map of the wind vector can be made. This technique was evaluated in 11 flights over the Virginia and Maryland offshore WEAs. Heights above the ocean surface planned for wind turbines are shown to be within the marine boundary layer, and the wind vector is seen to show variation across the geographical area of interest at turbine heights.

  8. Cloning vector

    DOEpatents

    Guilfoyle, R.A.; Smith, L.M.

    1994-12-27

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.

  9. Cloning vector

    DOEpatents

    Guilfoyle, Richard A.; Smith, Lloyd M.

    1994-01-01

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.

  10. Holocene changes in a park-forest vegetation mosaic in the Wind River Range, Wyoming

    SciTech Connect

    Lynch, E.A. )

    1994-06-01

    The modern mod-elevation vegetation of the Rocky Mountains is a mosaic of conifer forests and open parks dominated by sagebrush (Artemisia spp.), grasses, and other herbs. It is not known how this pattern originated or how sensitive the balance between forest and park is to disturbance. Using pollen from sediments of five small ponds in Fish Creek Park, WY (elev. 2700 m), I reconstructed the last 8000 yrs of changes in the park-forest mosaic in an are about 16 km[sup 2]. Surface samples collected from 52 ponds in the Fish Creek Park area and from forest and park sites in Wyoming and Colorado indicate that park and forest pollen assemblages can be distinguished using multivariate statistical methods and conifer:herb pollen ratios. Fossil pollen from the five sediment cores shows that the distribution of the two vegetation types on the landscape has changed through the Holocene, and that the changes in vegetation are gradual. Past changes from park to forest have apparently occurred much more slowly than changes from forest to park, suggesting that areas subjected to recent clearcutting may remain unforested for centuries.

  11. Changes in the High-Latitude Topside Ionospheric Vertical Electron-Density Profiles in Response to Solar-Wind Perturbations During Large Magnetic Storms

    NASA Astrophysics Data System (ADS)

    Benson, R. F.; Fainberg, J.; Osherovich, V. A.; Truhlik, V.; Wang, Y.; Arbacher, R. T.

    2011-12-01

    The latest results from an investigation to establish links between solar-wind and topside-ionospheric parameters will be presented including a case where high-latitude topside electron-density Ne(h) profiles indicated dramatic rapid changes in the scale height during the main phase of a large magnetic storm (Dst < -200 nT). These scale-height changes suggest a large heat input to the topside ionosphere at this time. The topside profiles were derived from ISIS-1 digital ionograms obtained from the NASA Space Physics Data Facility (SPDF) Coordinated Data Analysis Web (CDAWeb). Solar-wind data obtained from the NASA OMNIWeb database indicated that the magnetic storm was due to a magnetic cloud. This event is one of several large magnetic storms being investigated during the interval from 1965 to 1984 when both solar-wind and digital topside ionograms, from either Alouette-2, ISIS-1, or ISIS-2, are potentially available.

  12. Changes in the High-Latitude Topside Ionospheric Vertical Electron-Density Profiles in Response to Solar-Wind Perturbations During Large Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir; Truhlik, Vladimir; Wang, Yongli; Arbacher, Becca

    2011-01-01

    The latest results from an investigation to establish links between solar-wind and topside-ionospheric parameters will be presented including a case where high-latitude topside electron-density Ne(h) profiles indicated dramatic rapid changes in the scale height during the main phase of a large magnetic storm (Dst < -200 nT). These scale-height changes suggest a large heat input to the topside ionosphere at this time. The topside profiles were derived from ISIS-1 digital ionograms obtained from the NASA Space Physics Data Facility (SPDF) Coordinated Data Analysis Web (CDA Web). Solar-wind data obtained from the NASA OMNIWeb database indicated that the magnetic storm was due to a magnetic cloud. This event is one of several large magnetic storms being investigated during the interval from 1965 to 1984 when both solar-wind and digital topside ionograms, from either Alouette-2, ISIS-1, or ISIS-2, are potentially available.

  13. The molecular sensory machinery of a Chagas disease vector: expression changes through imaginal moult and sexually dimorphic features

    PubMed Central

    Latorre-Estivalis, Jose Manuel; Robertson, Hugh M.; Walden, Kimberly K. O.; Ruiz, Jerônimo; Gonçalves, Leilane Oliveira; Guarneri, Alessandra A.; Lorenzo, Marcelo Gustavo

    2017-01-01

    The triatomine bug Rhodnius prolixus is a main vector of Chagas disease, which affects several million people, mostly in Latin-America. Host searching, pheromone communication, and microclimatic preferences are aspects of its behaviour that depend on multimodal sensory inputs. The molecular bases of these sensory processes are largely unknown. The expression levels of genes transcribed in antennae were compared between 5th instar larvae, and female and male adults by means of RNA-Seq. The antennae of R. prolixus showed increased expression of several chemosensory-related genes in imaginal bugs, while both sexes had similar expression patterns for most target genes. Few cases suggest involvement of target genes in sexually dimorphic functions. Most odorant and ionotropic receptor genes seemed to be expressed in all libraries. OBPs and CSPs showed very high expression levels. Other sensory-related genes such as TRPs, PPKs and mechanoreceptors had consistent levels of expression in all libraries. Our study characterises most of the sensory gene repertoire of these insects, opening an avenue for functional genetics studies. The increase in expression of chemosensory genes suggests an enhanced role in adult bugs. This knowledge allows developing new behaviour interfering strategies, increasing the options for translational research in the vector control field. PMID:28059141

  14. Rice stripe virus affects the viability of its vector offspring by changing developmental gene expression in embryos

    PubMed Central

    Li, Shuo; Wang, Shijuan; Wang, Xi; Li, Xiaoli; Zi, Jinyan; Ge, Shangshu; Cheng, Zhaobang; Zhou, Tong; Ji, Yinghua; Deng, Jinhua; Wong, Sek-Man; Zhou, Yijun

    2015-01-01

    Plant viruses may affect the viability and development process of their herbivore vectors. Small brown planthopper (SBPH) is main vector of Rice stripe virus (RSV), which causes serious rice stripe disease. Here, we reported the effects of RSV on SBPH offspring by crossing experiments between viruliferous and non-viruliferous strains. The life parameters of offspring from different cross combinations were compared. The hatchability of F1 progeny from viruliferous parents decreased significantly, and viruliferous rate was completely controlled by viruliferous maternal parent. To better elucidate the underlying biological mechanisms, the morphology of eggs, viral propagation and distribution in the eggs and expression profile of embryonic development genes were investigated. The results indicated that RSV replicated and accumulated in SBPH eggs resulting in developmental stunt or delay of partial eggs; in addition, RSV was only able to infect ovum but not sperm. According to the expression profile, expression of 13 developmental genes was regulated in the eggs from viruliferous parents, in which two important regulatory genes (Ls-Dorsal and Ls-CPO) were most significantly down-regulated. In general, RSV exerts an adverse effect on SBPH, which is unfavourable for the expansion of viruliferous populations. The viewpoint is also supported by systematic monitoring of SBPH viruliferous rate. PMID:25601039

  15. The Winds of Change in Russian Higher Education: Is the East Moving West?

    ERIC Educational Resources Information Center

    Timoshenko, Konstantin

    2011-01-01

    In the last 30 years, major changes have taken place in the public sector worldwide under the rubric of New Public Management [NPM]. The education sector is perhaps one of the key areas drawing an intense interest and discussion in the wake of NPM. The Russian State seems to be no longer an exception to this global trend. In line with this, the…

  16. Winds of Change: Latinos in the Heartland and the Nation. JSRI Statistical Brief No. 5.

    ERIC Educational Resources Information Center

    Aponte, Robert; Siles, Marcelo E.

    This statistical brief provides a follow-up assessment of the changing demographic and economic landscape of the Midwest between 1980 and 1990. Latino population growth in the Midwest during the 1980s was modest, but since the region's other groups experienced minimal or negative growth, Latino growth accounted for over half the Midwest's total…

  17. Winds of Change in the English Language--Air of Peril for Native Speakers?

    ERIC Educational Resources Information Center

    Paradowski, Michal B.

    2008-01-01

    English today is one of the most hybrid and rapidly changing languages in the world. New users of the language are not just passively absorbing, but actively shaping it, breeding a variety of regional Englishes, as well as pidgins and English-lexified creoles. Also, as in an increasing number of countries English is becoming an element of core…

  18. Equivalent Vectors

    ERIC Educational Resources Information Center

    Levine, Robert

    2004-01-01

    The cross-product is a mathematical operation that is performed between two 3-dimensional vectors. The result is a vector that is orthogonal or perpendicular to both of them. Learning about this for the first time while taking Calculus-III, the class was taught that if AxB = AxC, it does not necessarily follow that B = C. This seemed baffling. The…

  19. Statistical Correction for Short-term Wind Forecasting

    NASA Astrophysics Data System (ADS)

    Jiang, J.; Tambke, J.; Heinemann, D.

    2009-04-01

    The uncertainty of wind speed forecasts from Numerical Weather Predictions (NWP) is a main source of errors in wind power forecasts. Despite increased accuracy of wind power forecasts in the last years, large wind power forecast errors still occur due to local weather and/or synoptic systems that either develop locally or that are phase-shifted relative to the forecast. The main error sources of NWP are, amongst others, inaccurate initial and/or lateral boundary conditions and inadequate representation of local forcing. Wind measurements in the WMEP program and the wind field forecasts of DWD-LM(German Weather Service - Local Model) in 2004 and from Sept. to Dec. of 2006 are used for correcting DWD-LM wind forecasts. In order to remove systematic error, phase error, or local-scale error in wind forecasts, three kinds of methods, bias correction, phase correction and Cressman technique are applied. Using bias increments changing with wind direction, the wind forecasts are modified. After bias correction, RMSE ( Root Mean Square Error ) of corrected forecasts decrease 0.1m/s to 0.4m/s. Diurnal or seasonal change of bias is also important. In addition, with optimum phase-shift vectors, the phase-shift correction is applied. It reduces the RMSE about 0.1m/s to 0.5m/s at different time steps. Moreover, statistical Cressman correction increments were obtained by Cressman technique and used to correct wind forecasts. After Cressman correction, the RMSE of wind forecasts decreases 0.1m/s to 0.2m/s. The results show that bias correction, phase correction and Cressman scheme do, to some extent, improve wind speed forecasts. That contributes to the improvement of wind power forecasts. As part of the new EU-project "SafeWind", we are continuing that study with NWP-data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and wind speed observations over Europe.

  20. Assessing climate change impacts on the near-term stability of the wind energy resource over the United States

    PubMed Central

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

    2011-01-01

    The energy sector comprises approximately two-thirds of global total greenhouse gas emissions. For this and other reasons, renewable energy resources including wind power are being increasingly harnessed to provide electricity generation potential with negligible emissions of carbon dioxide. The wind energy resource is naturally a function of the climate system because the “fuel” is the incident wind speed and thus is determined by the atmospheric circulation. Some recent articles have reported historical declines in measured near-surface wind speeds, leading some to question the continued viability of the wind energy industry. Here we briefly articulate the challenges inherent in accurately quantifying and attributing historical tendencies and making robust projections of likely future wind resources. We then analyze simulations from the current generation of regional climate models and show, at least for the next 50 years, the wind resource in the regions of greatest wind energy penetration will not move beyond the historical envelope of variability. Thus this work suggests that the wind energy industry can, and will, continue to make a contribution to electricity provision in these regions for at least the next several decades. PMID:21536905

  1. Assessing climate change impacts on the near-term stability of the wind energy resource over the United States.

    PubMed

    Pryor, S C; Barthelmie, R J

    2011-05-17

    The energy sector comprises approximately two-thirds of global total greenhouse gas emissions. For this and other reasons, renewable energy resources including wind power are being increasingly harnessed to provide electricity generation potential with negligible emissions of carbon dioxide. The wind energy resource is naturally a function of the climate system because the "fuel" is the incident wind speed and thus is determined by the atmospheric circulation. Some recent articles have reported historical declines in measured near-surface wind speeds, leading some to question the continued viability of the wind energy industry. Here we briefly articulate the challenges inherent in accurately quantifying and attributing historical tendencies and making robust projections of likely future wind resources. We then analyze simulations from the current generation of regional climate models and show, at least for the next 50 years, the wind resource in the regions of greatest wind energy penetration will not move beyond the historical envelope of variability. Thus this work suggests that the wind energy industry can, and will, continue to make a contribution to electricity provision in these regions for at least the next several decades.

  2. Wind speed forecasting for wind energy applications

    NASA Astrophysics Data System (ADS)

    Liu, Hong

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

  3. Circular Conditional Autoregressive Modeling of Vector Fields.

    PubMed

    Modlin, Danny; Fuentes, Montse; Reich, Brian

    2012-02-01

    As hurricanes approach landfall, there are several hazards for which coastal populations must be prepared. Damaging winds, torrential rains, and tornadoes play havoc with both the coast and inland areas; but, the biggest seaside menace to life and property is the storm surge. Wind fields are used as the primary forcing for the numerical forecasts of the coastal ocean response to hurricane force winds, such as the height of the storm surge and the degree of coastal flooding. Unfortunately, developments in deterministic modeling of these forcings have been hindered by computational expenses. In this paper, we present a multivariate spatial model for vector fields, that we apply to hurricane winds. We parameterize the wind vector at each site in polar coordinates and specify a circular conditional autoregressive (CCAR) model for the vector direction, and a spatial CAR model for speed. We apply our framework for vector fields to hurricane surface wind fields for Hurricane Floyd of 1999 and compare our CCAR model to prior methods that decompose wind speed and direction into its N-S and W-E cardinal components.

  4. Circular Conditional Autoregressive Modeling of Vector Fields*

    PubMed Central

    Modlin, Danny; Fuentes, Montse; Reich, Brian

    2013-01-01

    As hurricanes approach landfall, there are several hazards for which coastal populations must be prepared. Damaging winds, torrential rains, and tornadoes play havoc with both the coast and inland areas; but, the biggest seaside menace to life and property is the storm surge. Wind fields are used as the primary forcing for the numerical forecasts of the coastal ocean response to hurricane force winds, such as the height of the storm surge and the degree of coastal flooding. Unfortunately, developments in deterministic modeling of these forcings have been hindered by computational expenses. In this paper, we present a multivariate spatial model for vector fields, that we apply to hurricane winds. We parameterize the wind vector at each site in polar coordinates and specify a circular conditional autoregressive (CCAR) model for the vector direction, and a spatial CAR model for speed. We apply our framework for vector fields to hurricane surface wind fields for Hurricane Floyd of 1999 and compare our CCAR model to prior methods that decompose wind speed and direction into its N-S and W-E cardinal components. PMID:24353452

  5. The National assessment of shoreline shange—A GIS compilation of vector shorelines and associated shoreline change data for the Pacific Northwest coast

    USGS Publications Warehouse

    Kratzmann, Meredith G.; Himmelstoss, Emily A.; Ruggiero, Peter; Thieler, E. Robert; Reid, David

    2013-01-01

    Sandy ocean beaches are a popular recreational destination and are often surrounded by communities that consist of valuable real estate. Development along sandy coastal areas is increasing despite the fact that coastal infrastructure may be repeatedly subjected to flooding and erosion. As a result, the demand for accurate information regarding past and present shoreline changes is increasing. Investigators with the U.S. Geological Survey's National Assessment of Shoreline Change Project have compiled a comprehensive database of digital vector shorelines and rates of shoreline change for the Pacific Northwest coast including the states of Washington and Oregon. No widely accepted standard for analyzing shoreline change currently exists. Current measurement and methods for calculating rates of change vary from study to study, precluding the combination of study results into statewide or regional assessments. The impetus behind the national assessment was to develop a standardized method that is consistent from coast to coast for measuring changes in shoreline position. The goal was to facilitate the process of periodically and systematically updating the measurements in an internally consistent manner. A detailed report on shoreline change for the Pacific Northwest coast that contains a discussion of the data presented here is available and cited in the Geospatial Data section of this report.

  6. Solar Wind Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1995-01-01

    The magnetic fields originate as coronal fields that are converted into space by the supersonic, infinitely conducting, solar wind. On average, the sun's rotation causes the field to wind up and form an Archimedes Spiral. However, the field direction changes almost continuously on a variety of scales and the irregular nature of these changes is often interpreted as evidence that the solar wind flow is turbulent.

  7. Phlebotomines (Diptera: Psychodidae) in a Hydroelectric System Affected Area from Northern Amazonian Brazil: Further Insights into the Effects of Environmental Changes on Vector Ecology

    PubMed Central

    Furtado, Nercy Virginia Rabelo; Galardo, Allan Kardec Ribeiro; Galardo, Clicia Denis; Firmino, Viviane Caetano

    2016-01-01

    During 2012–2015, an entomological survey was conducted as part of a phlebotomine (Diptera: Psychodidae) monitoring program in an area influenced by the Santo Antônio do Jari hydroelectric system (Amapá State, Brazil). The purpose was to study aspects of Amazon/Guianan American cutaneous leishmaniasis (ACL) vectors subjected to stresses by anthropogenic environmental changes. For sampling, CDC light traps were positioned 0.5, 1, and 20 m above ground at five capture locations along the Jari River Basin. Fluctuations in phlebotomine numbers were analyzed to determine any correlation with rainfall, dam waterlogging, and/or ACL cases, from May 2012 to March 2015. We captured 2,800 individuals, and among 45 species identified, Bichromomyia flaviscutellata, Nyssomyia umbratilis, and Psychodopygus squamiventris s.l. were determined to be the main putative vectors, based on current knowledge of the Amazon/Guianan ACL scenario. Rainfall, but not complete flooding, was relatively correlated with phlebotomine fluctuation, mainly observed for Ps. squamiventris s.l., as were ACL cases with Ny. umbratilis. Behavioral changes were observed in the unexpected high frequency of Bi. flaviscutellata among CDC captures and the noncanopy dominance of Ny. umbratilis, possibly attributable to environmental stress in the sampled ecotopes. Continuous entomological surveillance is necessary to monitor the outcomes of these findings. PMID:28042300

  8. A review of thrust-vectoring schemes for fighter applications

    NASA Technical Reports Server (NTRS)

    Berrier, B. L.; Re, R. J.

    1978-01-01

    This paper presents a review of thrust vectoring schemes for advanced fighter applications. Results are presented from wind tunnel and system integration studies on thrust vectoring nozzle concepts. Vectoring data are presented from wind tunnel tests of axisymmetric C-D (convergent-divergent) and nonaxisymmetric wedge, C-D, single ramp and USB (upper-surface blowing) nozzle concepts. Results from recent airframe/nozzle integration studies on the impact of thrust vectoring on weight, cooling and performance characteristics are discussed. This review indicates that the aircraft designer has, at his disposal, a wide range of thrust vectoring schemes which offer potential for added or improved aircraft capability.

  9. Response of the Mediterranean Sea thermohaline circulation to observed changes in the winter wind stress field in the period 1980-1993

    NASA Astrophysics Data System (ADS)

    Samuel, Sarah; Haines, Keith; Josey, Simon; Myers, Paul G.

    1999-04-01

    This paper seeks to model changes in deep water production in the eastern Mediterranean induced by changes in winter wind stress. An analysis of individual monthly wind stress fields over the Mediterranean for 1980-1993 from the SOC flux data set shows that an intensification of the winter mean (mainly January) wind stress over the Aegean Sea and Levantine basin occurred in the latter half of this period. A weakening of the Mistral occurred at the same time. Two monthly wind stress climatologies were created using the 1980-1987 and 1988-1993 periods, and these were used to force an ocean general circulation model of the Mediterranean, with climatological surface T, S relaxation. The Levantine intermediate water (LIW) dispersal path in the Ionian is altered in the 1988-1993 experiment with no pathway to the Adriatic and, consequently, greatly reduced exchange at Otranto and a collapse in Adriatic deep water formation. In contrast, there is an increased exchange of LIW at the Cretan arc straits and enhanced Aegean deep water production in the 1988-1993 experiment. Much more Aegean water exits into the Levantine and Ionian basins as is shown by an east-west cross section south of Crete, along a similar path to the Meteor cruise in 1995. Changes in air-sea fluxes are diagnosed from the model showing a small increase in wintertime cooling over the Aegean and reduced cooling over the Adriatic after 1987. While the changes in air-sea fluxes are probably underrepresented by this simulation, the large changes induced by the wind forcing suggest this could be a mechanism in the altered thermohaline state of the eastern Mediterranean since 1987.

  10. Changes in soil CO2 efflux of organic calcaric soils due to disturbance by wind

    NASA Astrophysics Data System (ADS)

    Mayer, M.; Katzensteiner, K.

    2012-04-01

    Disturbances such as windthrow or insect infestations are supposed to have a significant influence on the soil carbon balance of affected forests. Increasing soil temperatures and changes in the soil moisture regime, caused by the removed tree layer, are expected to change soil CO2 efflux, also known as soil respiration. Beside an anticipated stimulation of the carbon mineralization, the main part of root allocated CO2 is offset due to the blown down trees. On mountain forest sites of the Northern Limestone Alps, where highly active organic soils above calcareous parent material are characteristic (Folic Histosols and Rendzic Leptosols), an increase of the mineralization rate of carbon may contribute to enormous humus losses. Serious site degradation can be the consequence, especially on south exposed slopes where extreme climatic conditions occur. The present study tries to give insights to disturbance induced changes in temporal and spatial behaviour of soil respiration for a montane mountain forest located in the Northern Limestone Alps of Upper Austria. Soil respiration, soil temperature and volumetric water content were measured on two windthrow areas (blow down dates were 2007 and 2009 respectively) as well as in an adjacent mature mixed forest during the vegetation periods of 2010 and 2011. Soil respiration in both years was mainly driven by soil temperature, which explained up to 90 % of the concerning temporal variation. Volumetric water content had a significant influence as additional temporal driver. After removing the temperature trend, significant differences in basal soil respiration rates were found for the disturbance area and the forest stand. Inter seasonal declines in soil respiration were ascertained for the mature stand as well as for the recent windthrow. Particular decreases are related to drought stress in summer 2011 and a proceeded decomposition of labile soil carbon components at the windthrow site. An interaction between soil type and

  11. Projected changes to South Atlantic boundary currents and confluence region in the CMIP5 models: the role of wind and deep ocean changes

    NASA Astrophysics Data System (ADS)

    Pontes, G. M.; Gupta, A. Sen; Taschetto, A. S.

    2016-09-01

    The South Atlantic (SA) circulation plays an important role in the oceanic teleconnections from the Indian, Pacific and Southern oceans to the North Atlantic, with inter-hemispheric exchanges of heat and salt. Here, we show that the large-scale features of the SA circulation are projected to change significantly under ‘business as usual’ greenhouse gas increases. Based on 19 models from the Coupled Model Intercomparison Project phase 5 there is a projected weakening in the upper ocean interior transport (<1000 m) between 15° and ˜32°S, largely related to a weakening of the wind stress curl over this region. The reduction in ocean interior circulation is largely compensated by a decrease in the net deep southward ocean transport (>1000 m), mainly related to a decrease in the North Atlantic deep water transport. Between 30° and 40°S, there is a consistent projected intensification in the Brazil current strength of about 40% (30%-58% interquartile range) primarily compensated by an intensification of the upper interior circulation across the Indo-Atlantic basin. The Brazil-Malvinas confluence is projected to shift southwards, driven by a weakening of the Malvinas current. Such a change could have important implications for the distribution of marine species in the southwestern SA in the future.

  12. ELECTRONIC BIVANE WIND DIRECTION INDICATOR

    DOEpatents

    Moses, H.

    1961-05-01

    An apparatus is described for determining and recording three dimensional wind vectors. The apparatus comprises a rotatably mounted azimuthal wind component sensing head and an elevational wind component sensing head mounted to the azimuthal head and adapted to rotate therewith in the azimuthal plane and independently in the elevational plane. A heat source and thermocouples disposed thereabout are mounted within each of the sensing heads, the thermocouples providing electrical signals responsive to the temperature differential created by the passage of air through the sensing tuhes. The thermocouple signals are applied to drive mechanisms which position the sensing heads to a null wind position. Recording means are provided responsive to positional data from the drive mechanisms which are a measurement of the three dimensional wind vectors.

  13. A Tropical Ocean Recharge Mechanism for Climate Variability. Part I: Equatorial Heat Content Changes Induced by the Off-Equatorial Wind.

    NASA Astrophysics Data System (ADS)

    Wang, Xiaochun; Jin, Fei-Fei; Wang, Yuqing

    2003-11-01

    A reduced-gravity shallow-water model, an oceanic general circulation model for the Pacific region, and the analytical model of the equatorial β plane bounded in the zonal direction are used to investigate the equatorial thermocline response to tropical and subtropical wind stress forcing. The results show that the wind stress forcing in the tropical and subtropical region can generate a nearly zonal uniform thermocline depth change in the equatorial region. The response timescale is longer when the wind stress is placed farther away from the equator. There exist latitude bands around 10° 15°N and 10° 15°S where the forcing can cause a relatively large equatorial response. When the forcing is located in the eastern basin, the response timescale is longer and its magnitude is larger than the case when the forcing is located in the western basin. Thus the eastern tropical to subtropical region is a relatively effective area for off-equatorial wind stress to generate an equatorial thermocline response. When the wind stress forcing has a longer period, the response of the equatorial thermocline has a larger magnitude. The results from this study's numerical experiments and the analytical solution are consistent. The present study has implications for the broad-scale ocean atmosphere interaction in the tropical region.

  14. Effects of sea state on offshore wind resourcing in Florida

    NASA Astrophysics Data System (ADS)

    Collier, Cristina

    Offshore resource assessment relies on estimating wind speeds at turbine hub height using observations typically made at substantially lower height. The methods used to adjust from observed wind speeds to hub height can impact resource estimation. The importance of directional sea state is examined, both as seasonal averages and as a function of the diurnal cycle. A General Electric 3.6 MW offshore turbine is used as a model for a power production. Including sea state increases or decreases seasonally averaged power production by roughly 1%, which is found to be an economically significant change. These changes occur because the sea state modifies the wind shear (vector wind difference between the buoy height and the moving surface) and therefore the extrapolation from the observation to hub height is affected. These seemingly small differences in capacity can alter profits by millions of dollars depending upon the size of the farm and fluctuations in price per kWh throughout the year. A 2% change in capacity factor can lead to a 10 million dollar difference from total kWh produced from a wind farm of 100 3.6MW turbines. These economic impacts can be a deciding factor in determining whether a resource is viable for development. Modification of power output due to sea states are shown for seasonal and diurnal time scales. Three regions are examined herein: West Florida, East Florida, and Nantucket Sound. The average capacity after sea state is included suggests areas around Florida could provide substantial amounts of wind power throughout three-fourths of the calendar year. At certain times of day winter average produced capacity factors in West Florida can be up to 45% more than in summer when sea state is included. Nantucket Sound capacity factors are calculated for comparison to a region near a planned United States offshore wind farm. This study provides evidence to suggest including sea state in offshore wind resource assessment causes economically significant

  15. Pollen, wind and fire: how to investigate genetic effects of disturbance-induced change in forest trees.

    PubMed

    Bacles, Cecile F E

    2014-01-01

    ) take advantage of the distinctive features of the fire-adapted wind-pollinated Aleppo pine Pinus halepensis (Fig. 1) to provide an elegant example of best practice. Thanks to long-term monitoring of the study site, a natural stand in Israel, Shohami and Nathan witnessed the direct impact of habitat disturbance, here taking the shape of fire, on conspecific and forest densities and compared pre- and postdisturbance mating patterns estimated from cones of different ages sampled on the same surviving maternal individuals (Fig. 2). This excellent study design is all the more strong that Shohami and Nathan took further analytical steps to account for confounding variables, such as historical population genetic structure and possible interannual variation in wind conditions, thus giving high credibility to their findings of unequivocal fire-induced alteration of mating patterns in P. halepensis. Most notably, the authors found, at the pollen pool level, a disruption of local genetic structure which, furthermore, they were able to attribute explicitly to enhanced pollen-mediated gene immigration into the low-density fire-disturbed stand. This cleverly designed research provides a model approach to be followed if we are to advance our understanding of disturbance-induced dispersal and genetic change in forest trees.

  16. Vector carpets

    SciTech Connect

    Dovey, D.

    1995-03-22

    Previous papers have described a general method for visualizing vector fields that involves drawing many small ``glyphs`` to represent the field. This paper shows how to improve the speed of the algorithm by utilizing hardware support for line drawing and extends the technique from regular to unstructured grids. The new approach can be used to visualize vector fields at arbitrary surfaces within regular and unstructured grids. Applications of the algorithm include interactive visualization of transient electromagnetic fields and visualization of velocity fields in fluid flow problems.

  17. Optimization of satellite coverage in observing cause and effect changes in the ionosphere, magnetosphere, and solar wind. Master's thesis

    SciTech Connect

    Loveless, M.J.

    1993-06-01

    Disturbances in the ionosphere sometimes cause adverse effects to communications systems, power grids, etc. on the earth. Currently, very little, if any, lead time is given to warn of an impending problem. If a forecast could be made of ionospheric occurrences, some lead time may be given to appropriate agencies and equipment may be saved. Most changes that occur in the ionosphere are a result of interaction of energy, currents, etc. between the magnetosphere and/or solar wind. Before a forecast can be made, however, improvement of ionospheric models currently in use need to be made. The models currently depict features in various regions of the ionosphere but not always where these features are actually observed. So an improvement to the model is needed to create an accurate baseline condition, or in other words an accurate depiction of the current ionosphere. Models could be improved by inputting real-time data from the ionosphere into the model. This data would come from satellites and/or ground-based stations.

  18. Satellite-derived sea surface height and sea surface wind data fusion for spilled oil tracking

    NASA Astrophysics Data System (ADS)

    Kozai, K.

    Data fusion is defined as a framework with the purpose of obtaining information of 'greater quality'. Within the framework tools are expressed for the alliance of data originating from different sources. The exact definition of 'greater quality' is stated in this context as more reliable prediction for the trajectory of spilled oil from two different microwave sensor data, namely ERS-2 altimeter and ADEOS/NSCAT scatterometer data. An example is presented in the case of trajectory of bow section and associated oil upwelling from the sunken tanker Nakhodka occurred from January to June in 1997 in Japan Sea. Spill distance is defined as a horizontal distance from the oil upwelling point to the location of sunken Nakhodka and a spill direction is defined as an angle made by the geographic north and the line corresponding to the spill distance. Geostrophic current vectors are derived from ERS-2 altimeter and wind-induced current vectors are derived from ADEOS/NSCAT scatterometer data. These two different satellite-derived vectors are 'fused' together in the surface current model to estimate and evaluate the trajectory of bow section and associated oil upwelling from the sunken tanker Nakhodka. Result of comparison between the estimated and the observed trajectory of bow section indicates that the estimated trajectory is agreed well with the observed one in the first half of drift period, while in the latter half of drift period the estimated trajectory is not agreed well with the observed one, which may be attributable to changes of wind directions within 24 hours from the satellite overpasses. Moreover the comparison between spill vector and 'fused' surface current vector shows the good correspondence in terms of direction when in situ wind accelerates the surface current vector, while the comparison between the twos shows the bad correspondence when the temporal changes of wind vector occurs.

  19. Wind farm and solar park effects on plant–soil carbon cycling: uncertain impacts of changes in ground-level microclimate

    PubMed Central

    Armstrong, Alona; Waldron, Susan; Whitaker, Jeanette; Ostle, Nicholas J

    2014-01-01

    Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land-based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground-level climate by a magnitude that could affect the fundamental plant–soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground-level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land-based renewable energy sources to alter plant–soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research. PMID:24132939

  20. Wind farm and solar park effects on plant-soil carbon cycling: uncertain impacts of changes in ground-level microclimate.

    PubMed

    Armstrong, Alona; Waldron, Susan; Whitaker, Jeanette; Ostle, Nicholas J

    2014-06-01

    Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land-based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground-level climate by a magnitude that could affect the fundamental plant-soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground-level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land-based renewable energy sources to alter plant-soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research.

  1. An oilspill trajectory analysis model with a variable wind deflection angle

    USGS Publications Warehouse

    Samuels, W.B.; Huang, N.E.; Amstutz, D.E.

    1982-01-01

    The oilspill trajectory movement algorithm consists of a vector sum of the surface drift component due to wind and the surface current component. In the U.S. Geological Survey oilspill trajectory analysis model, the surface drift component is assumed to be 3.5% of the wind speed and is rotated 20 degrees clockwise to account for Coriolis effects in the Northern Hemisphere. Field and laboratory data suggest, however, that the deflection angle of the surface drift current can be highly variable. An empirical formula, based on field observations and theoretical arguments relating wind speed to deflection angle, was used to calculate a new deflection angle at each time step in the model. Comparisons of oilspill contact probabilities to coastal areas calculated for constant and variable deflection angles showed that the model is insensitive to this changing angle at low wind speeds. At high wind speeds, some statistically significant differences in contact probabilities did appear. ?? 1982.

  2. Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour

    PubMed Central

    Fereres, Alberto; Peñaflor, Maria Fernanda G. V.; Favaro, Carla F.; Azevedo, Kamila E. X.; Landi, Carolina H.; Maluta, Nathalie K. P.; Bento, José Mauricio S.; Lopes, Joao R.S.

    2016-01-01

    Virus infection frequently modifies plant phenotypes, leading to changes in behaviour and performance of their insect vectors in a way that transmission is enhanced, although this may not always be the case. Here, we investigated Bemisia tabaci response to tomato plants infected by Tomato chlorosis virus (ToCV), a non-circulative-transmitted crinivirus, and Tomato severe rugose virus (ToSRV), a circulative-transmitted begomovirus. Moreover, we examined the role of visual and olfactory cues in host plant selection by both viruliferous and non-viruliferous B. tabaci. Visual cues alone were assessed as targets for whitefly landing by placing leaves underneath a Plexiglas plate. A dual-choice arena was used to assess whitefly response to virus-infected and mock-inoculated tomato leaves under light and dark conditions. Thereafter, we tested the whitefly response to volatiles using an active air-flow Y-tube olfactometer, and chemically characterized the blends using gas chromatography coupled to mass spectrometry. Visual stimuli tests showed that whiteflies, irrespective of their infectious status, always preferred to land on virus-infected rather than on mock-inoculated leaves. Furthermore, whiteflies had no preference for either virus-infected or mock-inoculated leaves under dark conditions, but preferred virus-infected leaves in the presence of light. ToSRV-infection promoted a sharp decline in the concentration of some tomato volatiles, while an increase in the emission of some terpenes after ToCV infection was found. ToSRV-viruliferous whiteflies preferred volatiles emitted from mock-inoculated plants, a conducive behaviour to enhance virus spread, while volatiles from ToCV-infected plants were avoided by non-viruliferous whiteflies, a behaviour that is likely detrimental to the secondary spread of the virus. In conclusion, the circulative persistent begomovirus, ToSRV, seems to have evolved together with its vector B. tabaci to optimise its own spread. However

  3. Roles of surface wind, NDVI and snow cover in the recent changes in Asian dust storm occurrence frequency

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Jae; Kim, Cheol-Hee

    2012-11-01

    This paper describes the recent variations in dust outbreak during the period from 1996 to 2007 over the Asian dust source regions. The Asian dust source regions were divided into four sub-regions; S1, Taklamakan; S2, Gobi; S3, Inner Mongolia-Manchuria; and S4, Loess, and the WMO SYNOP observation and satellite data were employed to analyze the features of recently changed dust outbreak frequencies (DOFs). There was no particular variation in region S1, but the recent spatiotemporal variations in DOFs over S2-S4 were well characterized by a severe and widespread increase in 2001-2002, and significant decreasing in 2003-2004 over the most source regions, with a steadily increasing trend again during 2005-2007. Seasonal features showed that the highest DOFs occurred in March-April before 2002, but was delayed by a month toward April-May during the next five years because of the shift in the month of highest strong wind-speed frequencies (SWFs). A secondary peak of DOF was also found, occurring in October-November since the year 2000. Over all the source regions, the primary controlling factor for explaining the spatiotemporal DOF patterns was the SWF, with a pattern correlation coefficient (PCC) of 0.66-0.76. Other secondary controlling factors varied from region to region. For example, the DOFs observed in region S2-S3 showed relatively greater sensitivity to the snow-cover fraction, and region S4 showed a better correlation with the normalized difference vegetation index (NDVI) than the other regions. Other recent significant changes in DOFs over the Asian dust source regions and their causes are also discussed in this study.

  4. DSCOVR High Time Resolution Solar Wind Measurements

    NASA Technical Reports Server (NTRS)

    Szabo, Adam

    2012-01-01

    The Deep Space Climate Observatory (DSCOVR), previously known as Triana, spacecraft is expected to be launched in late 2014. It will carry a fluxgate magnetometer, Faraday Cup solar wind detector and a top-hat electron electrostatic analyzer. The Faraday Cup will provide an unprecedented 10 vectors/sec time resolution measurement of the solar wind proton and alpha reduced distribution functions. Coupled with the 40 vector/sec vector magnetometer measurements, the identification of specific wave modes in the solar wind will be possible for the first time. The science objectives and data products of the mission will be discussed.

  5. Analyticity constraints on the strangeness changing vector current and applications to τ→Kπντ and τ→Kππντ

    NASA Astrophysics Data System (ADS)

    Moussallam, B.

    2008-02-01

    We discuss matrix elements of the strangeness changing vector current using their relation, due to analyticity, with πK scattering in the P-wave. We take into account experimental phase-shift measurements in the elastic channel as well as results, obtained by the LASS collaboration, on the details of inelastic scattering, which show the dominance of two quasi-two-body channels at medium energies. The associated form factors are shown to be completely determined, up to one flavor symmetry breaking parameter, imposing boundary conditions at t=0 from chiral and flavor symmetries and at t→∞ from QCD. We apply the results to the τ→Kπντ and τ→Kππντ amplitudes and compare the former to recent high statistics results from B factories.

  6. Automatic differentiation using vectorized hyper dual numbers

    NASA Astrophysics Data System (ADS)

    Swaroop, Kshitiz

    Sensitivity analysis is a method to measure the change in a dependent variable with respect to one or more independent variables with uses including optimization, design analysis and risk modeling. Conventional methods like finite difference suffer from both truncation, subtraction errors and cannot be used to simultaneously calculate derivatives of an output with respect to multiple inputs (commonly seen in optimization problems). Automatic Differentiation tackles all these issues successfully allowing us to calculate derivatives of any variable with respect to the independent variables in a computer program up to machine precision without any significant user input. Vectorized Hyper Dual Numbers, an extension of Hyper Dual Numbers, which allows the user to automatically calculate both the Hessian and derivative along with the function evaluation is developed for this thesis. The method is then used for the sizing and layup of a composite wind turbine blade as a proof of concept.

  7. Wind-driven changes of surface current, temperature, and chlorophyll observed by satellites north of New Guinea

    NASA Astrophysics Data System (ADS)

    Radenac, Marie-Hélène; Léger, Fabien; Messié, Monique; Dutrieux, Pierre; Menkes, Christophe; Eldin, Gérard

    2016-04-01

    Satellite observations of wind, sea level and derived currents, sea surface temperature (SST), and chlorophyll are used to expand our understanding of the physical and biological variability of the ocean surface north of New Guinea. Based on scarce cruise and mooring data, previous studies differentiated a trade wind situation (austral winter) when the New Guinea Coastal Current (NGCC) flows northwestward and a northwest monsoon situation (austral summer) when a coastal upwelling develops and the NGCC reverses. This circulation pattern is confirmed by satellite observations, except in Vitiaz Strait where the surface northwestward flow persists. We find that intraseasonal and seasonal time scale variations explain most of the variance north of New Guinea. SST and chlorophyll variabilities are mainly driven by two processes: penetration of Solomon Sea waters and coastal upwelling. In the trade wind situation, the NGCC transports cold Solomon Sea waters through Vitiaz Strait in a narrow vein hugging the coast. Coastal upwelling is generated in westerly wind situations (westerly wind event, northwest monsoon). Highly productive coastal waters are advected toward the equator and, during some westerly wind events, toward the eastern part of the warm pool. During El Niño, coastal upwelling events and northward penetration of Solomon Sea waters combine to influence SST and chlorophyll anomalies.

  8. Wind Simulation

    SciTech Connect

    Walker, Howard Andrew

    2008-12-31

    The Software consists of a spreadsheet written in Microsoft Excel that provides an hourly simulation of a wind energy system, which includes a calculation of wind turbine output as a power-curve fit of wind speed.

  9. Vectors, Change of Basis and Matrix Representation: Onto-Semiotic Approach in the Analysis of Creating Meaning

    ERIC Educational Resources Information Center

    Montiel, Mariana; Wilhelmi, Miguel R.; Vidakovic, Draga; Elstak, Iwan

    2012-01-01

    In a previous study, the onto-semiotic approach was employed to analyse the mathematical notion of different coordinate systems, as well as some situations and university students' actions related to these coordinate systems in the context of multivariate calculus. This study approaches different coordinate systems through the process of change of…

  10. The interacting winds of Eta Carinae: Observed forbidden line changes and the Forbidden Blue(-Shifted) Crab

    NASA Astrophysics Data System (ADS)

    Gull, Theodore R.; Madura, Thomas; Corcoran, Michael F.; Teodoro, Mairan; Richardson, Noel; Hamaguchi, Kenji; Groh, Jose H.; Hillier, Desmond John; Damineli, Augusto; Weigelt, Gerd

    2015-01-01

    The massive binary, Eta Carinae (EC), produces such massive winds that strong forbidden line emission of singly- and doubly-ionized iron traces wind-wind interactions from the current cycle plus fossil interactions from one, two and three 5.54-year cycles ago.With an eccentricity of >0.9, the >90 solar mass primary (EC-A) and >30 solar mass secondary (EC-B) approach to within 1.5 AU during periastron and recede to nearly 30 AU across apastron. The wind-wind structures move outward driven by the 420 km/s primary wind interacting with the ~3000 km/s secondary wind yielding partially-accelerated compressed primary wind shells that are excited by mid-UV from EC-A and in limited lines of sight, FUV from EC-B.These structures are spectroscopically and spatially resolved by HST's Space Telescope Imaging Spectrograph. At critical binary phases, we have mapped the central 2'x2' region in the light of [Fe III] and [Fe II] with spatial resolution of 0.12' and velocity resolution of 40 km/s.1) The bulk of forbidden emission originates from the large cavity northwest of EC and is due to ionization of massive ejecta from the 1840s and 1890s eruptions. The brightest clumps are the Weigelt Blobs C and D, but there are additionally multiple, fainter emission clumps. Weigelt B appears to have faded.2) Three concentric, red-shifted [FeII] arcs expand at ~470 km/s excited by mid-UV of EC-A.3) The structure of primarily blue-shifted [Fe III] emission resembles a Maryland Blue Crab. The claws appear at the early stages of the high-excitation recovery from the periastron passage, expand at radial velocities exceeding the primary wind terminal velocity, 420 km/s and fade as the binary system approaches periastron with the primary wind enveloping the FUV radiation from EC-B.4) All [Fe III] emission faded by late June 2014 and disappeared by August 2, 2014, the beginning of periastron passage.Comparisons to HST/STIS observations between 1998 to 2004.3 indicate long-term fading of [Fe II

  11. Relating high-Latitude Topside Ionospheric Vertical Electron-Density-Profile changes to Solar-Wind Parameters During Large Magnetic Storms

    NASA Astrophysics Data System (ADS)

    Benson, R. F.; Fainberg, J.; Osherovich, V.; Truhlik, V.; Wang, Y.; Bilitza, D.; Lam, H.

    2012-12-01

    Ten large magnetic storms (Dst < -100 nT) where high-latitude topside electron-density profiles Ne(h) could be obtained from Alouette/ISIS topside-sounder data, and where solar-wind data were available, were investigated. The former were obtained from the NASA Space Physics Data Facility (SPDF) and the latter were obtained from the NASA OMNIWeb database. Large Ne(h) changes were observed during the storms in all cases. In some cases large topside Ne(h) gradients were observed between adjacent ionograms (separated by ~ ½ minute) and even within a single ionogram (profiles separated by < 10 s). The changes in the winter profiles have a clear relationship with the solar-wind velocity Vsw in that the topside Ne(h) increases with increasing Vsw during nighttime and decreases with increasing Vsw during daytime.

  12. The national assessment of shoreline change: a GIS compilation of vector cliff edges and associated cliff erosion data for the California coast

    USGS Publications Warehouse

    Hapke, Cheryl; Reid, David; Borrelli, Mark

    2007-01-01

    The U.S. Geological Survey has generated a comprehensive data clearinghouse of digital vector cliff edges and associated rates of cliff retreat along the open-ocean California coast. These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Cliff erosion is a chronic problem along many coastlines of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of coastal cliff retreat. There is also a critical need for these data to be consistent from one region to another. One objective of this work is to a develop standard, repeatable methodology for mapping and analyzing cliff edge retreat so that periodic, systematic, and internally consistent updates of cliff edge position and associated rates of erosion can be made at a national scale. This data compilation for open-ocean cliff edges for the California coast is a separate, yet related study to Hapke and others, 2006 documenting shoreline change along sandy shorelines of the California coast, which is itself one in a series that includes the Gulf of Mexico and the Southeast Atlantic coast (Morton and others, 2004; Morton and Miller, 2005). Future reports and data compilations will include coverage of the Northeast U.S., the Great Lakes, Hawaii and Alaska. Cliff edge change is determined by comparing the positions of one historical cliff edge digitized from maps with a modern cliff edge derived from topographic LIDAR (light detection and ranging) surveys. Historical cliff edges for the California coast represent the 1920s-1930s time-period; the most recent cliff edge was delineated using data collected between 1998 and 2002. End-point rate calculations were used to evaluate rates of erosion between the two cliff edges. Please refer to our full report on cliff edge erosion along the California

  13. Wind tunnel pressure distribution tests on a series of biplane wing models Part II : effects of changes in decalage, dihedral, sweepback and overhang

    NASA Technical Reports Server (NTRS)

    Knight, Montgomery; Noyes, Richard W

    1929-01-01

    This preliminary report furnishes information on the changes in the forces on each wing of a biplane cellule when the decalage, dihedral, sweepback and overhang are separately varied. The data were obtained from pressure distribution tests made in the Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. Since each test was carried up to 90 degree angle of attack, the results may be used in the study of stalled flight and of spinning and in the structural design of biplane wings.

  14. New techniques in 3D scalar and vector field visualization

    SciTech Connect

    Max, N.; Crawfis, R.; Becker, B.

    1993-05-05

    At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.

  15. Sea ice circulation around the Beaufort Gyre: The changing role of wind forcing and the sea ice state

    NASA Astrophysics Data System (ADS)

    Petty, Alek A.; Hutchings, Jennifer K.; Richter-Menge, Jacqueline A.; Tschudi, Mark A.

    2016-05-01

    Sea ice drift estimates from feature tracking of satellite passive microwave data are used to investigate seasonal trends and variability in the ice circulation around the Beaufort Gyre, over the multidecadal period 1980-2013. Our results suggest an amplified response of the Beaufort Gyre ice circulation to wind forcing, especially during the late 2000s. We find increasing anticyclonic ice drift across all seasons, with the strongest trend in autumn, associated with increased ice export out of the southern Beaufort Sea (into the Chukchi Sea). A flux gate analysis highlights consistency across a suite of drift products. Despite these seasonal anticyclonic ice drift trends, a significant anticyclonic wind trend occurs in summer only, driven, in-part, by anomalously anticyclonic winds in 2007. Across all seasons, the ice drift curl is more anticyclonic than predicted from a linear relationship to the wind curl in the 2000s, compared to the 1980s/1990s. The strength of this anticyclonic ice drift curl amplification is strongest in autumn and appears to have increased since the 1980s (up to 2010). In spring and summer, the ice drift curl amplification occurs mainly between 2007 and 2010. These results suggest nonlinear ice interaction feedbacks (e.g., a weaker, more mobile sea ice pack), enhanced atmospheric drag, and/or an increased role of the ocean. The results also show a weakening of the anticyclonic wind and ice circulation since 2010.

  16. Delineation of QRS offset by instantaneous changes in ECG vector angle can improve detection of acute inferior myocardial infarctions.

    PubMed

    Starc, Vito; Schlegel, Todd T

    2016-01-01

    We developed an automated new method for determining QRS offset, based on angular velocity (AV) changes around the QRS loop, and compared the method's performance to that of manual and more established automated methods for determining QRS offset in both healthy subjects and patients with acute myocardial infarction (AMI). Specifically, using Frank leads reconstructed from standard 12-lead ECGs, we determined AV in the direction of change raised to the 4th power, d(t). We found that the d(t)-determined AV transition (ΔAV) nearly coincided with manually determined QRS offset in healthy subjects, and in 27 patients with anterior AMI. However, in 31 patients with inferior AMI, ΔAV typically preceded that of QRS offset determined by the established automated methods, and by more than 10ms in 32% of cases. While this "ΔAV precedence" coincided with diagnostic ST elevation in only a minority of patients with recent inferior AMI, the use of ΔAV precedence as a complement to traditional determination of ST elevation increased the sensitivity for detecting inferior AMIs from 23 to 42%.

  17. Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments

    PubMed Central

    Srivastava, Anubhav; Philip, Nisha; Hughes, Katie R.; Georgiou, Konstantina; MacRae, James I.; Barrett, Michael P.; McConville, Malcolm J.

    2016-01-01

    Malaria parasites (Plasmodium spp.) encounter markedly different (nutritional) environments during their complex life cycles in the mosquito and human hosts. Adaptation to these different host niches is associated with a dramatic rewiring of metabolism, from a highly glycolytic metabolism in the asexual blood stages to increased dependence on tricarboxylic acid (TCA) metabolism in mosquito stages. Here we have used stable isotope labelling, targeted metabolomics and reverse genetics to map stage-specific changes in Plasmodium berghei carbon metabolism and determine the functional significance of these changes on parasite survival in the blood and mosquito stages. We show that glutamine serves as the predominant input into TCA metabolism in both asexual and sexual blood stages and is important for complete male gametogenesis. Glutamine catabolism, as well as key reactions in intermediary metabolism and CoA synthesis are also essential for ookinete to oocyst transition in the mosquito. These data extend our knowledge of Plasmodium metabolism and point towards possible targets for transmission-blocking intervention strategies. Furthermore, they highlight significant metabolic differences between Plasmodium species which are not easily anticipated based on genomics or transcriptomics studies and underline the importance of integration of metabolomics data with other platforms in order to better inform drug discovery and design. PMID:28027318

  18. Some like it hot: a differential response to changing temperatures by the malaria vectors Anopheles funestus and An. gambiae s.l.

    PubMed Central

    2017-01-01

    Background With the possible implications of global warming, the effect of temperature on the dynamics of malaria vectors in Africa has become a subject of increasing interest. Information from the field is, however, relatively sparse. We describe the effect of ambient temperature over a five-year period on the dynamics of An. funestus and An. gambiae s.l., collected from a single village in southern Mozambique where temperatures varied from a night-time minimum of 6 °C in the cool season to a daytime maximum of 35 °C in the hot season. Results Mean daily air temperatures varied from 34 °C to 20 °C and soil temperatures varied from 26 °C to 12 °C. Diurnal variation was greatest in the cooler months of the year and were greater in air temperatures than soil temperatures. During the study 301, 705 female An. funestus were collected in 6,043 light-trap collections, 161, 466 in 7,397 exit collections and 16, 995 in 1,315 resting collections. The equivalent numbers for An. gambiae s.l. are 72,475 in light-traps, 33, 868 in exit collections and 5,333 from indoor resting collections. Numbers of mosquito were greatest in the warmer months. Numbers of An. gambiae s.l. went through a one hundredfold change (from a mean of 0.14 mosquitoes a night to 14) whereas numbers of An. funestus merely doubled (from a mean of 20 to 40 a night). The highest environmental correlations and mosquito numbers were between mean air temperature (r2 = 0.52 for An. funestus and 0.77 for An. gambiae s.l.). Numbers of mosquito collected were not related to rainfall with lags of up to four weeks. Numbers of both gravid and unfed An. gambiae complex females in exit collections continued to increase at all temperatures recorded but gravid females of An. funestus decreased at temperatures above 28 °C. Overall the numbers of gravid and unfed An. funestus collected in exit collections were not correlated (p = 0.07). For an unknown reason the number of An. gambiae s.l. fell below monitoring

  19. Summertime wind climate in Yerevan: valley wind systems

    NASA Astrophysics Data System (ADS)

    Gevorgyan, Artur

    2017-03-01

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

  20. Fighting wind shear

    NASA Astrophysics Data System (ADS)

    A “coherent and sustained program” of improved radar detection of weather, pilot training, and better communication between pilots and air controllers can greatly reduce the risk of wind shear to airplanes landing or taking off, according to a National Research Council (NRC) committee.Wind shear, characterized by winds rapidly changing direction and speed, has caused several serious accidents in recent years; among the most notable is the July 8, 1982, crash of a Pan American World Airlines jetliner at the New Orleans International Airport, which killed 153 persons. Following the accident, Congress directed the Federal Aviation Administration (FAA) to contract with the NRC to study wind shear.

  1. Wind turbine means

    SciTech Connect

    Kennon, W.A.

    1980-12-02

    A turbine wheel is described which includes a housing for enclosing the electrical generating apparatus, and track structure which engages and rotatably drives the generator or the like, i.e., through suitable coupling structure. Shroud structure is disposed in an operable exterior proximity with the turbine wheel for varying the effectiveness of the wind as it is acting upon the turbine wheel, i.e., in infinite variable stages commensurate with changing velocity of the wind. The speed of the turbine wheel is automatically controlled so as to remain substantially constant throughout a wide variance of normal wind velocity and irrespective of the direction of the wind.

  2. Winds of Change: The Physics of Accretion, Ejection, and X-ray Variability in GRS1915+105

    NASA Astrophysics Data System (ADS)

    Neilsen, Joseph

    2013-04-01

    In the last twenty years, even as multiwavelength observations of black hole X-ray binaries have led to major advances, the microquasar GRS 1915+105 has continually challenged our understanding of the physics of accretion and ejection. With its relativistic jets, ionized winds, and myriad states of rapid, extreme variability, this remarkable black hole has been alternately seen as the black sheep of X-ray binaries and a Rosetta stone for black hole astrophysics. In this talk, I will present our efforts to use a decade of high-resolution X-ray spectroscopy of GRS 1915+105 to shed light on the processes that regulate its erratic behavior. I will highlight in particular the role of accretion disk winds on time scales ranging from seconds to years. Drawing on recent results, I will discuss the broader implications of these massive winds for the physics of inflows and outflows around black holes.

  3. Wind direction variability in Afternoon and Sunset Turbulence

    NASA Astrophysics Data System (ADS)

    Nilsson, Erik; Lothon, Marie; Lohou, Fabienne; Mahrt, Larry

    2014-05-01

    Understanding wind direction (WD) variability better is important for several reasons. Air pollution models need information about how variable wind direction is in different conditions (Davies and Thomson 1999). Accurate predictions of dispersion are important for human health and safety and allow for adaptation planning (Nagle et al. 2011). Other applications include horizontal diffusion, efficiency and fatigue of wind machines and air-sea interaction (Mahrt 2011). Most studies of wind direction variability have focused on nocturnal conditions because of greater variability in light winds. Modelling WD variability in transition periods when both mean wind speed and variance of the wind components are in a state of change can, however, also be very challenging and has not been the focus of earlier studies. The evening transitioning to the nocturnal boundary layer can play an important role in the diffusion process of pollutants and scalars emitted at surface and transported within the atmosphere. The Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign that took place in southern France in June and July 2011 focused on the decaying turbulence of the late afternoon boundary layer and related issues (Lothon et al. 2012). We analyse field measurements from BLLAST to investigate WD variability in the evening transition period. Standard deviations of horizontal wind direction fluctuations in the lowest 60 m of the boundary layer have been examined for dependence on mean wind speed, higher order moments and averaging time. Measurement results are interpreted using measured and idealized probability density functions of horizontal wind vectors. These are also used to develop analytical functions describing how WD variability depends on wind speed, variance and other controlling factors in the atmospheric boundary layer. References: Davies B.M., Thomson D.J., 1999. Comparison of some parameterizations of wind direction variability with observations

  4. Erosion: Wind

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion refers to the detachment, transport and deposition of sediment by wind. It is a dynamic, physical process where loose, dry, bare soils are transported by strong winds. Wind erosion is a soil degrading process that affects over 500 million ha of land worldwide and creates between 500 an...

  5. Meteorology (Wind)

    Atmospheric Science Data Center

    2014-09-25

    Wind speed at 50 m (m/s) The average and percent difference minimum and ... are given.   Percent of time for ranges of wind speed at 50 m (percent) Percentage [frequency] of time that wind ... be adjusted to heights from 10 to 300 meters using the Gipe power law. Wind speeds may be adjusted for different terrain by selecting from ...

  6. Accuracy of land use change detection using support vector machine and maximum likelihood techniques for open-cast coal mining areas.

    PubMed

    Karan, Shivesh Kishore; Samadder, Sukha Ranjan

    2016-08-01

    One objective of the present study was to evaluate the performance of support vector machine (SVM)-based image classification technique with the maximum likelihood classification (MLC) technique for a rapidly changing landscape of an open-cast mine. The other objective was to assess the change in land use pattern due to coal mining from 2006 to 2016. Assessing the change in land use pattern accurately is important for the development and monitoring of coalfields in conjunction with sustainable development. For the present study, Landsat 5 Thematic Mapper (TM) data of 2006 and Landsat 8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS) data of 2016 of a part of Jharia Coalfield, Dhanbad, India, were used. The SVM classification technique provided greater overall classification accuracy when compared to the MLC technique in classifying heterogeneous landscape with limited training dataset. SVM exceeded MLC in handling a difficult challenge of classifying features having near similar reflectance on the mean signature plot, an improvement of over 11 % was observed in classification of built-up area, and an improvement of 24 % was observed in classification of surface water using SVM; similarly, the SVM technique improved the overall land use classification accuracy by almost 6 and 3 % for Landsat 5 and Landsat 8 images, respectively. Results indicated that land degradation increased significantly from 2006 to 2016 in the study area. This study will help in quantifying the changes and can also serve as a basis for further decision support system studies aiding a variety of purposes such as planning and management of mines and environmental impact assessment.

  7. Changes in sea-level pressure over South Korea associated with high-speed solar wind events

    NASA Astrophysics Data System (ADS)

    Cho, Il-Hyun; Kwak, Young-Sil; Marubashi, Katsuhide; Kim, Yeon-Han; Park, Young-Deuk; Chang, Heon-Young

    2012-09-01

    We explore a possibility that the daily sea-level pressure (SLP) over South Korea responds to the high-speed solar wind event. This is of interest in two aspects: first, if there is a statistical association this can be another piece of evidence showing that various meteorological observables indeed respond to variations in the interplanetary environment. Second, this can be a very crucial observational constraint since most models proposed so far are expected to preferentially work in higher latitude regions than the low latitude region studied here. We have examined daily solar wind speed V, daily SLP difference ΔSLP, and daily log(BV2) using the superposed epoch analysis in which the key date is set such that the daily solar wind speed exceeds 800 km s-1. We find that the daily ΔSLP averaged out of 12 events reaches its peak at day +1 and gradually decreases back to its normal level. The amount of positive deviation of ΔSLP is +2.5 hPa. The duration of deviation is a few days. We also find that ΔSLP is well correlated with both the speed of solar wind and log(BV2). The obtained linear correlation coefficients and chance probabilities with one-day lag for two cases are r ≃ 0.81 with P > 99.9%, and r ≃ 0.84 with P > 99.9%, respectively. We conclude by briefly discussing future direction to pursue.

  8. Patchiness in wind erosion-deposition patterns in response to a recent state change reversal in the Chihuahuan Desert

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shifts from shrub-dominated states to grasslands are believed to be irreversible as a result of positive feedbacks between woody plants and soil properties. In the Chihuahuan Desert, mesquite (Prosopis glandulosa) expansion into black grama (Bouteloua eriopoda) grasslands is maintained by wind redis...

  9. Comparison of dayside and nightside reconnection changes resulting from a sudden enhancement in solar wind dynamic pressure

    NASA Astrophysics Data System (ADS)

    Boudouridis, A.; Zesta, E.; Lyons, L. R.; Ruohoniemi, J. M.; Lummerzheim, D.; Anderson, P. C.

    2007-12-01

    Magnetic reconnection at the dayside magnetopause is the main process by which mass, energy, and momentum from the solar wind enter the terrestrial magnetosphere. Magnetic reconnection at the nightside energizes magnetotail plasma and closes the lobe open flux, thus completing the cycle that initiates and sustains magnetospheric convection. Understanding the drivers of reconnection and convection in the magnetosphere is one of the primary goals of magnetospheric physics. It has long been recognized that the Interplanetary Magnetic Field (IMF) is the most influential factor in initiation of reconnection and convection in the magnetosphere. Recent evidence has shown that the solar wind dynamic pressure plays also an important role in enhancing both dayside and nightside reconnection, and driving enhanced ionospheric convection. Super Dual Auroral Radar Network (SuperDARN) observations show that solar wind pressure fronts induce significantly enhanced ionospheric convection in the dayside ionosphere. In parallel, Defense Meteorological Satellite Program (DMSP) precipitating particle measurements and POLAR Ultra-Violet Imager (UVI) images have demonstrated that sudden solar wind pressure increases also significantly affect the size of the polar cap. The polar cap is observed to shrink after an increase in solar wind pressure, especially on the nightside, suggesting an enhancement of magnetotail reconnection. MHD models of the interaction of the magnetosphere with solar wind pressure fronts have managed to reproduce the enhancement of dayside reconnection, but have failed so far to account for the observed closing of the polar cap on the nightside and the suggested magnetotail reconnection increase. We use SuperDARN observations of ionospheric convection within both the dayside and nightside polar ionosphere, including near the magnetic separatrix, to evaluate the relative strengths of the observed dayside and nightside reconnection enhancements after an abrupt increase

  10. Controlling Compressor Vane Flow Vectoring Angles at Transonic Speeds

    NASA Astrophysics Data System (ADS)

    Munson, Matthew; Rempfer, Dietmar; Williams, David; Acharya, Mukund

    2003-11-01

    The ability to control flow separation angles from compressor inlet guide vanes with a Coanda-type actuator is demonstrated using both wind tunnel experiments and finite element simulations. Vectoring angles up to 40 degrees from the uncontrolled baseline state were measured with helium schlieren visualization at transonic Mach numbers ranging from 0.1 to 0.6, and with airfoil chord Reynolds numbers ranging from 89,000 to 710,000. The magnitude of the vectoring angle is shown to depend upon the geometry of the trailing edge, and actuator slot size, and the momentum flux coefficient. Under certain conditions the blowing has no effect on the vectoring angle indicating that the Coanda effect is not present. DNS simulations with the finite element method investigated the effects of geometry changes and external flow. Continuous control of the vectoring angle is demonstrated, which has important implications for application to rotating machinery. The technique is shown to reduce the stall flow coefficient by 15 percent in an axial flow compressor.

  11. Experimental investigation of change of energy of infragavity waves in dependence on spectral characteristics of an irregular wind waves in coastal zone

    NASA Astrophysics Data System (ADS)

    Saprykina, Yana; Divinskii, Boris

    2013-04-01

    An infragravity waves are long waves with periods of 20 - 300 s. Most essential influence of infragarvity waves on dynamic processes is in a coastal zone, where its energy can exceed the energy of wind waves. From practical point of view, the infragravity waves are important, firstly, due to their influence on sand transport processes in a coastal zone. For example, interacting with group structure of wind waves the infragravity waves can define position of underwater bars on sandy coast. Secondly, they are responsible on formation of long waves in harbors. Main source of infragravity waves is wave group structure defined by sub-nonlinear interactions of wind waves (Longuet-Higgins, Stewart, 1962). These infragravity waves are bound with groups of wind waves and propagate with wave group velocity. Another type of infragravity waves are formed in a surf zone as a result of migration a wave breaking point (Symonds, et al., 1982). What from described above mechanisms of formation of infragravity waves prevails, till now it is unknown. It is also unknown how energy of infragravity waves depends on energy of input wind waves and how it changes during nonlinear wave transformation in coastal zone. In our work on the basis of the analysis of data of field experiment and numerical simulation a contribution of infragravity waves in total wave energy in depending on integral characteristics of an irregular wave field in the conditions of a real bathymetry was investigated. For analysis the data of field experiment "Shkorpilovtsy-2007" (Black sea) and data of numerical modeling of Boussinesq type equation with extended dispersion characteristics (Madsen et al., 1997) were used. It was revealed that infragravity waves in a coastal zone are defined mainly by local group structure of waves, which permanently changes due to nonlinearity, shoaling and breaking processes. Free infragravity waves appearing after wave breaking exist together with bound infragravity waves. There are

  12. Evaluating the effects of land use and cover change on the decrease of surface wind speed over China in recent 30 years using a statistical downscaling method

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Zha, Jinlin; Zhao, Deming

    2017-01-01

    The long-term decrease of surface wind speed (SWS) has been revealed by previous studies in China in recent decades, but the reasons for the SWS decrease remain uncertain. In this paper, we evaluated the effects of land use and cover change (LUCC) on the SWS decrease during 1980-2011 over the Eastern China Plain (ECP) region using a combined method of statistical downscaling and observation minus reanalysis data, which was used to improve the climate prediction of general circulation models and to evaluate the influence of LUCC on climate change. To exclude the potential influence of LUCC on SWS observation, a statistical downscaling model (SDM) was established during 1980-1992 because a lower extent of LUCC occurred during this period than in later periods. The skill of the SDM was checked by comparing the results of different predictor combinations. Then, SDM was used to improve the wind speed data at 10 m above the surface in the ERA-Interim reanalysis data (V10m-ERA) during 1993-2011, which decreased the error in the reanalysis wind speed as far as possible. Then, the difference between the station observed SWS (V10m-OBV) and the downscaled SWS (V10m-SDM) during 1993-2011 (SWSD) was considered the quantitative estimation of the influence of the LUCC on SWS in this period. The V10m-SDM can capture both the large-scale and local characteristics in the observation, and their patterns are very similar. V10m-SDM has better performance in the spatial-temporal changes than does V10m-ERA with respect to V10m-OBV. The impact of LUCC on the SWS was pronounced, the SWSD was -0.24 m s-1 in 1993, and the SWSD reached -0.56 m s-1 in 2011. LUCC could induce a 0.17 m s-1 wind speed decrease per 10 year in the ECP region during 1993-2011. Furthermore, each 10 % rise of the urbanization rate could cause an approximately 0.12 m s-1 decrease in wind speed. Additionally, pressure-gradient force was eliminated as the primary cause of the observed long-term decrease of SWS in ECP by

  13. Fabrication of four-path remote outdoor wind velocity measurement system and its performance evaluation

    NASA Astrophysics Data System (ADS)

    Yamada, Akira; Oba, Kensyo; Shimizu, Masato

    2017-01-01

    A method is proposed for the remote measurement of the outdoor ground-surface two-dimensional (2D) vector wind velocity field averaged over a region of 10-50 m size. To this end, four-channel (4ch) sound wave transmitters and receivers were placed at the corners of a rectangular monitoring site. From the four-path travel time data, the wind velocity and direction averaged over the region were estimated under the uniform-wind-field assumption. By this method, misestimation due to the local turbulence wind field, which is encountered in conventional in situ-type anemometers, can be avoided. To achieve a satisfying speed data collection that keeps up with the rapid changes in real wind field, coded modulation signals were transmitted and received simultaneously between all the 4ch speaker/microphone pairs. Test experiments demonstrated that time variations of vector wind velocities spatially averaged over the area were successively measured with satisfying speed and accuracy.

  14. Seasonal changes in estuarine dissolved organic matter due to variable flushing time and wind-driven mixing events

    NASA Astrophysics Data System (ADS)

    Dixon, Jennifer L.; Osburn, Christopher L.; Paerl, Hans W.; Peierls, Benjamin L.

    2014-12-01

    This study examined the seasonality of dissolved organic matter (DOM) sources and transformations within the Neuse River estuary (NRE) in eastern North Carolina between March 2010 and February 2011. During this time, monthly surface and bottom water samples were collected along the longitudinal axis of the NRE, ranging from freshwater to mesohaline segments. The monthly mean of all surface and bottom measurements made on collected samples was used to clarify larger physical mixing controls in the estuary as a whole. By comparing monthly mean trends in DOM and chromophoric dissolved organic matter (CDOM) properties in surface and bottom waters during varying hydrological conditions, we found that DOM and CDOM quality in the NRE is controlled by a combination of discharge, wind speed, and wind direction. The quality of DOM was assessed using C:N ratios, specific ultraviolet absorption at 254 nm (SUVA254), the absorption spectral slope ratio (SR), and the humification (HIX) and biological (BIX) indices from fluorescence. The NRE reflects allochthonous sources when discharge and flushing time are elevated at which times SUVA254 and HIX increased relative to base flow. During periods of reduced discharge and long flushing times in the estuary, extensive autochthonous production modifies the quality of the DOM pool in the NRE. This was evidenced by falling C:N values, and higher BIX and SR values. Lastly, a combination of increased wind speed and shifts in wind direction resulted in benthic resuspension events of degraded, planktonic OM. Thus, the mean DOM characteristics in this shallow micro-tidal estuary can be rapidly altered during episodic mixing events on timescales of a few weeks.

  15. Changes in quality of life and perceptions of general health before and after operation of wind turbines.

    PubMed

    Jalali, Leila; Bigelow, Philip; McColl, Stephen; Majowicz, Shannon; Gohari, Mahmood; Waterhouse, Ryan

    2016-09-01

    Ontario is Canada's provincial leader in wind energy, with over 4000 MW of installed capacity supplying approximately five percent of the province's electricity demand. Wind energy is now one of the fastest-growing sources of renewable power in Canada and many other countries. However, its possible negative impact on population health, as a new source of environmental noise, has raised concerns for people living in proximity to wind turbines (WTs). The aims of this study were to assess the effect of individual differences and annoyance on the self-reported general health and health-related quality of life (QOL) of nearby residents, using a pre- and post-exposure design. Prospective cohort data were collected before and after WT operations, from the individuals (n = 43) in Ontario, Canada. General health and QOL metrics were measured using standard scales, such as SF12, life satisfaction scales developed by Diener (SWLS) and the Canadian Community Health Survey (CCHS-SWL). The mean values for the Mental Component Score of SF12 (p = 0.002), SWLS (p < 0.001), and CCHS-SWL (p = 0.044) significantly worsened after WT operation for those participants who had a negative attitude to WTs, who voiced concerns about property devaluation, and/or who reported being visually or noise annoyed.

  16. Emotional tone of ontario newspaper articles on the health effects of industrial wind turbines before and after policy change.

    PubMed

    Deignan, Benjamin; Hoffman-Goetz, Laurie

    2015-01-01

    Newspapers are often a primary source of health information for the public about emerging technologies. Information in newspapers can amplify or attenuate readers' perceptions of health risk depending on how it is presented. Five geographically distinct wind energy installations in Ontario, Canada were identified, and newspapers published in their surrounding communities were systematically searched for articles on health effects from industrial wind turbines from May 2007 to April 2011. The authors retrieved 421 articles from 13 community, 2 provincial, and 2 national newspapers. To measure the emotional tone of the articles, the authors used a list of negative and positive words, informed from previous studies as well as from a random sample of newspaper articles included in this study. The majority of newspaper articles (64.6%, n = 272) emphasized negative rather than positive/neutral tone, with community newspapers publishing a higher proportion of negative articles than provincial or national newspapers, χ(2)(2) = 15.1, p < .001. Articles were more likely to be negative when published 2 years after compared with 2 years before provincial legislation to reduce dependence on fossil fuels (the Green Energy Act), χ(2)(3) = 9.7, p < .05. Repeated public exposure to negative newspaper content may heighten readers' health risk perceptions about wind energy.

  17. Dengue Vectors and their Spatial Distribution

    PubMed Central

    Higa, Yukiko

    2011-01-01

    The distribution of dengue vectors, Ae. aegypti and Ae. albopictus, is affected by climatic factors. In addition, since their life cycles are well adapted to the human environment, environmental changes resulting from human activity such as urbanization exert a great impact on vector distribution. The different responses of Ae. aegypti and Ae albopictus to various environments result in a difference in spatial distribution along north-south and urban-rural gradients, and between the indoors and outdoors. In the north-south gradient, climate associated with survival is an important factor in spatial distribution. In the urban-rural gradient, different distribution reflects a difference in adult niches and is modified by geographic and human factors. The direct response of the two species to the environment around houses is related to different spatial distribution indoors and outdoors. Dengue viruses circulate mainly between human and vector mosquitoes, and the vector presence is a limiting factor of transmission. Therefore, spatial distribution of dengue vectors is a significant concern in the epidemiology of the disease. Current technologies such as GIS, satellite imagery and statistical models allow researchers to predict the spatial distribution of vectors in the changing environment. Although it is difficult to confirm the actual effect of environmental and climate changes on vector abundance and vector-borne diseases, environmental changes caused by humans and human behavioral changes due to climate change can be expected to exert an impact on dengue vectors. Longitudinal monitoring of dengue vectors and viruses is therefore necessary. PMID:22500133

  18. Comparison of Satellite-Derived Wind Measurements with Other Wind Measurement Sensors

    NASA Technical Reports Server (NTRS)

    Susko, Michael; Herman, Leroy

    1995-01-01

    The purpose of this paper is to compare the good data from the Jimsphere launches with the data from the satellite system. By comparing the wind speeds from the Fixed Pedestal System 16 (FPS-16) Radar/Jimsphere Wind System and NASA's 50-MHz Radar Wind Profiler, the validation of winds from Geostationary Operational Environmental Satellite 7 (GOES-7) is performed. This study provides an in situ data quality check for the GOES-7 satellite winds. Comparison was made of the flowfields in the troposphere and the lower stratosphere of case studies of pairs of Jimsphere balloon releases and Radar Wind Profiler winds during Space Shuttle launches. The mean and standard deviation of the zonal component statistics, the meridional component statistics, and the power spectral density curves show good agreement between the two wind sensors. The standard deviation of the u and v components for the STS-37 launch (consisting of five Jimsphere/Radar Wind Profiler data sets) was 1.92 and 1.67 m/s, respectively; for the STS-43 launch (there were six Jimsphere/Wind Profiler data sets) it was 1.39 and 1.44 m/s, respectively. The overall standard deviation was 1.66 m/s for the u component and 1.55 m/s tor the v component, and a standard deviation of 2.27 m/s tor the vector wind difference. The global comparison of satellite with Jimsphere balloon vector winds shows a standard deviation of 3.15 m/s for STS-43 and 4.37 m/s for STS-37. The overall standard deviation of the vector wind was 3.76 m/s, with a root-mean-square vector difference of 4.43 m/s. These data have demonstrated that this unique comparison of the Jimsphere and satellite winds provides excellent ground truth and a frame of reference during testing and validation of satellite data

  19. Two Key Discoveries on Atmospheric Turbulent Wind Forcing of Nonsteady Wind Turbine Loadings, from HPC

    NASA Astrophysics Data System (ADS)

    Brasseur, James; Vijayakumar, Ganesh; Lavely, Adam; Jayaraman, Balaji; Paterson, Eric; Sullivan, Peter

    2014-11-01

    Loading transients on wind turbine blades underlie premature component failure. We research the underlying causes of nonsteady blade loadings from interactions with atmospheric eddies in the atmospheric boundary layer (ABL) using combinations of blade-boundary-layer-resolving HPC simulation and lower-order blade models (ALM, BEMT). A daytime ABL simulated with a 760 760 256 pseudo-spectral LES interacts with a 62 m rotating wind turbine blade, simulated with advanced finite-volume-based algorithms in two complex multi-grid/scale domains in relative motion. We focus on two key discoveries: (1) Whereas nonsteady blade loadings are generally interpreted as in response to nonsteadiness in wind speed, time changes in wind vector direction are a much greater contributor to load transients, and strongly impact boundary layer dynamics; (2) Large temporal variations in loadings occur within two disparate time scales, an advective time scale associated with atmospheric eddy passage, and a sub blade-rotation time scale associated with turbulence-induced forcings as the blades traverse internal atmospheric eddy structure. The latter generates the strongest transients; the former modulates the response. Supported by DOE & NSF. Computer resources by XSEDE, OLCF, NREL.

  20. Offshore Wind Power Integration in severely fluctuating Wind Conditions

    NASA Astrophysics Data System (ADS)

    von Bremen, L.

    2010-09-01

    Strong power fluctuations from offshore wind farms that are induced by wind speed fluctuations pose a severe problem to the save integration of offshore wind power into the power supply system. Experience at the first large-scale offshore wind farm Horns Rev showed that spatial smoothing of power fluctuations within a single wind farm is significantly smaller than onshore results suggest when distributed wind farms of 160 MW altogether are connected to a single point of common-coupling. Wind power gradients larger than 10% of the rated capacity within 5 minutes require large amount of regulation power that is very expensive for the grid operator. It must be noted that a wind speed change of only 0.5m/s result in a wind power change of 10% (within the range of 9-11 m/s where the wind power curve is steepest). Hence, it is very important for the grid operator to know if strong fluctuations are likely or not. Observed weather conditions at the German wind energy research platform FINO1 in the German bight are used to quantify wind fluctuations. With a standard power curve these wind fluctuations are transfered to wind power. The aim is to predict the probability of exceedence of certain wind power gradients that occur in a time interval of e.g. 12 hours. During 2006 and 2009 the distribution of wind power fluctuations looks very similar giving hope that distinct atmospheric processes can be determined that act as a trigger. Most often high wind power fluctuations occur in a range of wind speeds between 9-12 m/s as can be expected from the shape of the wind power curve. A cluster analysis of the 500 hPa geopotential height to detect predominant weather regimes shows that high fluctuations are more likely in north-western flow. It is shown that most often high fluctuations occur in non-stable atmospheric stratification. The description of stratification by means of the vertical gradient of the virtual potential temperature is chosen to be indicative for convection, i

  1. Continuous measurements of air change rates in an occupied house for 1 year: the effect of temperature, wind, fans, and windows.

    PubMed

    Wallace, L A; Emmerich, S J; Howard-Reed, C

    2002-07-01

    A year-long investigation of air change rates in an occupied house was undertaken to establish the effects of temperature, wind velocity, use of exhaust fans, and window-opening behavior. Air change rates were calculated by periodically injecting a tracer gas (SF(6)) into the return air duct and measuring the concentration in 10 indoor locations sequentially every minute by a gas chromatograph equipped with an electron capture detector. Temperatures were also measured outdoors and in the 10 indoor locations. Relative humidity (RH) was measured outdoors and in five indoor locations every 5 min. Wind speed and direction in the horizontal plane were measured using a portable meteorological station mounted on the rooftop. Use of the thermostat-controlled attic fan was recorded automatically. Indoor temperatures increased from 21 degrees C in winter to 27 degrees C in summer. Indoor RH increased from 20% to 70% in the same time period. Windows were open only a few percent of the time in winter but more than half the time in summer. About 4600 hour-long average air change rates were calculated from the measured tracer gas decay rates. The mean (SD) rate was 0.65 (0.56) h(-1). Tracer gas decay rates in different rooms were very similar, ranging only from 0.62 to 0.67 h(-1), suggesting that conditions were well mixed throughout the year. The strongest influence on air change rates was opening windows, which could increase the rate to as much as 2 h(-1) for extended periods, and up to 3 h(-1) for short periods of a few hours. The use of the attic fan also increased air change rates by amounts up to 1 h(-1). Use of the furnace fan had no effect on air change rates. Although a clear effect of indoor-outdoor temperature difference could be discerned, its magnitude was relatively small, with a very large temperature difference of 30 degrees C (54 degrees F) accounting for an increase in the air change rate of about 0.6 h(-1). Wind speed and direction were found to have very

  2. Wind measurements for non-uniform wind fields from spaceborne scatterometers

    NASA Technical Reports Server (NTRS)

    Chi, Chong-Yung; Li, Fuk K.

    1987-01-01

    Radar backscattering coefficient measurements by spaceborne scatterometers are presently simulated for the case of nonuniform wind fields, by means of a detailed numerical integration of the radar equation. The winds thus estimated are then compared with a nominal field which is defined as the average wind vector over the wind cell. The simulation results obtained for the NASA scatterometer are presented for cases of random wind fields whose spectra are consistent with the Seasat scatterometer sea surface wind spectrum. When the nonuniformity is small, system noise dominates the wind error; wind error degradation is therefore small for both perfect and imperfect coregistration cases. When it is relatively large, however, the wind error degradation persistently increases for both perfect and imperfect coregistrations.

  3. Vector statistics of LANDSAT imagery

    NASA Technical Reports Server (NTRS)

    Jayroe, R. R., Jr.; Underwood, D.

    1977-01-01

    A digitized multispectral image, such as LANDSAT data, is composed of numerous four dimensional vectors, which quantitatively describe the ground scene from which the data are acquired. The statistics of unique vectors that occur in LANDSAT imagery are studied to determine if that information can provide some guidance on reducing image processing costs. A second purpose of this report is to investigate how the vector statistics are changed by various types of image processing techniques and determine if that information can be useful in choosing one processing approach over another.

  4. Estimating the impact of the changes in land use and cover on the surface wind speed over the East China Plain during the period 1980-2011

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Zha, Jinlin; Zhao, Deming

    2016-02-01

    Long-term changes in surface wind speed (SWS) are influenced by both large-scale circulation and relative resistance. The effects of large-scale circulation are embodied by the pressure-gradient force (PGF), which is mostly a natural factor, whereas the resistance is due to the drag between the air and the surface as well as in the different boundary layers, which is mainly caused by the anthropogenic land use and cover change (LUCC). We performed experiments using a simple dynamical method in which a balance among the PGF, Coriolis force, and drag is reached to separate the effects of the PGF and LUCC on the SWS, and then, to quantitatively estimate the influence of the LUCC on the SWS over the East China Plain (ECP) during the period 1980-2011. The results show a distinct decrease in the SWS in the station observation data with a rate of -0.13 m s-1 (10 year)-1, but there is no statistically significant long-term trend in the reanalysis data. At the same time, the drag coefficient induced by the LUCC shows an increasing trend, which is consistent with the 30 % increase in the rate of urbanization during the study period. In addition, the PGF fluctuates with distinct seasonal and interannual changes, and it has an insignificant long-term increasing trend during the period 1980-2011. At the same time, the spatial distribution of the linear trend coefficient of the normalized PGF is inconsistent with that of the SWS, but the linear trend coefficient of the normalized drag coefficient shows a similar spatial distribution as the SWS. Therefore, the increase in the drag coefficient induced by the LUCC should account for the long-term decrease in the SWS. The difference between the model wind speed, in which the drag coefficient is constrained to its value in the year 1980, and the observed wind speed at each station (SWSD) can reflect the influence of the LUCC on the SWS. Furthermore, the long-term changes in East Asian monsoons may not completely account for the

  5. Wind turbine

    SciTech Connect

    McMahon II, E. H.

    1985-10-15

    A wind turbine, having at least one pair of sail means, each said sail means having upper and lower portions hingedly connected together to permit said portions to move away from and towards each other to thus open and close, respectively, said sail means being in the shape of an airfoil; a vertical shaft; a support; means mounting said vertical shaft in said support for rotation about the vertical axis of said shaft; and means mounting said sail means to said shaft, said sail means being disposed to move under the action of the wind in a plane about said vertical axis; said mounting means for said sail means including means for opening and closing one sail means of each pair of sail means while the other sail means of said pair is closed and opened, respectively, as said sail means moves about said vertical axis in said plane, said mounting means for said sail means being operable to dispose said plane at a predetermined angle to the horizontal and being adjustable to change said angle as desired.

  6. Wind Streaks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 12 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

    Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

    Windstreaks are features caused by the interaction of wind and topographic landforms. The raised rims and bowls of impact craters causes a complex interaction such that the wind vortex in the lee of the crater can both scour away the surface dust and deposit it back in the center of the lee. If you look closely, you will see evidence of this in a darker 'rim' enclosing a brighter interior.

    Image information: VIS instrument. Latitude 6.9, Longitude 69.4 East (290.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon

  7. Bottom-current and wind-pattern changes as indicated by Late Glacial and Holocene sediments from western Lake Geneva (Switzerland)

    USGS Publications Warehouse

    Girardclos, S.; Baster, I.; Wildi, W.; Pugin, A.; Rachoud-Schneider, A. -M.

    2003-01-01

    The Late-Glacial and Holocene sedimentary history of the Hauts-Monts area (western Lake Geneva, Switzerland) is reconstructed combining high resolution seismic stratigraphy and well-dated sedimentary cores. Six reflections and seismic units are defined and represented by individual isopach maps, which are further combined to obtain a three-dimensional age-depth model. Slumps, blank areas and various geometries are identified using these seismic data. The sediment depositional areas have substantially changed throughout the lake during the end of the Late-Glacial and the Holocene. These changes are interpreted as the result of variations in the intensity of deep lake currents and the frequency of strong winds determining the distribution of sediment input from the Versoix River and from reworking of previously deposited sediments within the lacustrine basin. The identified changes in sediment distribution allowed us to reconstruct the lake's deep-current history and the evolution of dominant strong wind regimes from the Preboreal to present times.

  8. ACARS wind measurements - An intercomparison with radiosonde, cloud motion and VAS thermally derived winds. [Communications, Addressing and Reporting System VISSR Atmospheric Sounder

    NASA Technical Reports Server (NTRS)

    Lord, R. J.; Menzel, W. P.; Pecht, L. E.

    1984-01-01

    Statistical comparisons between winds measured by ACARS and winds obtained from radiosondes, geostationary satellite image cloud motions, and VAS are presented. Observations from three separate comparisons reveal over 60 percent of wind vector magnitude differences are within 9 m/s, and 70 percent of the directional differences are within 15 deg. The comparisons indicate that the ACARS system provides an independent source of wind data that complements other sources of wind data for constructing composite wind field analyses.

  9. Changes in Meteorological Parameters (i.e. UV and Solar Radiation, Air Temperature, Humidity and Wind Condition) during the Partial Solar Eclipse of 9 March 2016

    NASA Astrophysics Data System (ADS)

    Paramitha, B.; Zaen, R.; Nandiyanto, A. B. D.

    2017-03-01

    Solar eclipse is a spectacular phenomenon, which occurs when the position of the moon is between the sun and the earth. This phenomenon affects to the meteorological parameters, such as solar radiation, temperature, and humidity. The purpose of this study was to evaluate the impact of partial solar eclipse of 9 March 2016 to the change of several meteorological parameters. In the experimental procedure, we used automatic weather station (AWS) in one of building in Universitas Pendidikan Indonesia in Bandung. Bandung was selected because this place experienced partial (88.89%) solar eclipse on 9 March 2016. The result showed that compared to normal day, meteorological parameters changed during the solar eclipse, such as decreases in the UV and solar radiation, increases in relative humidity, and changes in air temperature and wind condition.

  10. Wind motor applications for transportation

    SciTech Connect

    Lysenko, G.P.; Grigoriev, B.V.; Karpin, K.B.

    1996-12-31

    Motion equation for a vehicle equipped with a wind motor allows, taking into account the drag coefficients, to determine the optimal wind drag velocity in the wind motor`s plane, and hence, obtain all the necessary data for the wind wheel blades geometrical parameters definition. This optimal drag velocity significantly differs from the flow drag velocity which determines the maximum wind motor power. Solution of the motion equation with low drag coefficients indicates that the vehicle speed against the wind may be twice as the wind speed. One of possible transportation wind motor applications is its use on various ships. A ship with such a wind motor may be substantially easier to steer, and if certain devices are available, may proceed in autonomous control mode. Besides, it is capable of moving within narrow fairways. The cruise speed of a sailing boat and wind-motored ship were compared provided that the wind velocity direction changes along a harmonic law with regard to the motion direction. Mean dimensionless speed of the wind-motored ship appears to be by 20--25% higher than that of a sailing boat. There was analyzed a possibility of using the wind motors on planet rovers in Mars or Venus atmospheric conditions. A Mars rover power and motor system has been assessed for the power level of 3 kW.

  11. Modeling the role of environmental variables on the population dynamics of the malaria vector Anopheles gambiae sensu stricto

    PubMed Central

    2012-01-01

    Background The impact of weather and climate on malaria transmission has attracted considerable attention in recent years, yet uncertainties around future disease trends under climate change remain. Mathematical models provide powerful tools for addressing such questions and understanding the implications for interventions and eradication strategies, but these require realistic modeling of the vector population dynamics and its response to environmental variables. Methods Published and unpublished field and experimental data are used to develop new formulations for modeling the relationships between key aspects of vector ecology and environmental variables. These relationships are integrated within a validated deterministic model of Anopheles gambiae s.s. population dynamics to provide a valuable tool for understanding vector response to biotic and abiotic variables. Results A novel, parsimonious framework for assessing the effects of rainfall, cloudiness, wind speed, desiccation, temperature, relative humidity and density-dependence on vector abundance is developed, allowing ease of construction, analysis, and integration into malaria transmission models. Model validation shows good agreement with longitudinal vector abundance data from Tanzania, suggesting that recent malaria reductions in certain areas of Africa could be due to changing environmental conditions affecting vector populations. Conclusions Mathematical models provide a powerful, explanatory means of understanding the role of environmental variables on mosquito populations and hence for predicting future malaria transmission under global change. The framework developed provides a valuable advance in this respect, but also highlights key research gaps that need to be resolved if we are to better understand future malaria risk in vulnerable communities. PMID:22877154

  12. Wind driven air pump

    SciTech Connect

    Beisel, V.A.

    1983-05-31

    An improved pump for lifting water from an underground source utilizes a wind motor for driving an oil-less air compressor eliminating oil contamination of ground water which is forced to the surface. The wind motor is movable to face the wind by means of a novel swivel assembly which also eliminates the formation and freezing of condensate within the airline from the compressor. The propeller blades of the wind motor and the tail section are formed from a pair of opposed convex air foil shaped surfaces which provide the propeller blades and the tail section with fast sensitivity to slight changes in wind direction and speed. A novel well tower for supporting the wind motor and compressor and for lifting the water from the underground source is an optional modification which requires no welding and eliminates the problem of condensate freezing in the airline going to the well. The wind driven air pump disclosed is lightweight, can be easily installed, is relatively inexpensive to produce and is virtually maintenance-free and capable of operating in winds exceeding 100 miles per hour.

  13. Probability distribution of wind retrieval error for the NASA scatterometer

    NASA Technical Reports Server (NTRS)

    Leotta, Daniel F.; Long, David G.

    1989-01-01

    The NASA scatterometer (NSCAT) is a spaceborne scatterometer scheduled to be deployed in the mid-1990s. An analysis of the wind retrieval error distribution for wind estimates based on backscatter measurements made by the NSCAT instrument is presented. The results are based on an end-to-end simulation of the scatterometer instrument and data processing. In general, the distribution of the wind speed error, when normalized, is independent of the true wind speed and direction. The wind speed error can be characterized by a normal distribution. The wind direction error is independent of the true wind speed, but depends on the true wind direction. Details for wind vectors with true wind speeds from 3 m/s to 33 m/s and true wind directions from 0 to 360 deg are presented.

  14. Reproductive allocation in plants as affected by elevated carbon dioxide and other environmental changes: a synthesis using meta-analysis and graphical vector analysis.

    PubMed

    Wang, Xianzhong; Taub, Daniel R; Jablonski, Leanne M

    2015-04-01

    Reproduction is an important life history trait that strongly affects dynamics of plant populations. Although it has been well documented that elevated carbon dioxide (CO2) in the atmosphere greatly enhances biomass production in plants, the overall effect of elevated CO2 on reproductive allocation (RA), i.e., the proportion of biomass allocated to reproductive structures, is little understood. We combined meta-analysis with graphical vector analysis to examine the overall effect of elevated CO2 on RA and how other environmental factors, such as low nutrients, drought and elevated atmospheric ozone (O3), interacted with elevated CO2 in affecting RA in herbaceous plants. Averaged across all species of different functional groups and environmental conditions, elevated CO2 had little effect on RA (-0.9%). RA in plants of different reproductive strategies and functional groups, however, differed in response to elevated CO2. For example, RA in iteroparous wild species decreased by 8%, while RA in iteroparous crops increased significantly (+14%) at elevated CO2. RA was unaffected by CO2 in plants grown with no stress or in low-nutrient soils. RA decreased at elevated CO2 and elevated O3, but increased in response to elevated CO2 in drought-stressed plants, suggesting that elevated CO2 could ameliorate the adverse effect of drought on crop production to some extent. Our results demonstrate that elevated CO2 and other global environmental changes have the potential to greatly alter plant community composition through differential effects on RA of different plant species and thus affect the dynamics of natural and agricultural ecosystems in the future.

  15. Monitoring Wind Turbine Loading Using Power Converter Signals

    NASA Astrophysics Data System (ADS)

    Rieg, C. A.; Smith, C. J.; Crabtree, C. J.

    2016-09-01

    The ability to detect faults and predict loads on a wind turbine drivetrain's mechanical components cost-effectively is critical to making the cost of wind energy competitive. In order to investigate whether this is possible using the readily available power converter current signals, an existing permanent magnet synchronous generator based wind energy conversion system computer model was modified to include a grid-side converter (GSC) for an improved converter model and a gearbox. The GSC maintains a constant DC link voltage via vector control. The gearbox was modelled as a 3-mass model to allow faults to be included. Gusts and gearbox faults were introduced to investigate the ability of the machine side converter (MSC) current (I q) to detect and quantify loads on the mechanical components. In this model, gearbox faults were not detectable in the I q signal due to shaft stiffness and damping interaction. However, a model that predicts the load change on mechanical wind turbine components using I q was developed and verified using synthetic and real wind data.

  16. Solar wind eddies and the heliospheric current sheet

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Mccomas, D. J.; Bame, S. J.; Goldstein, B. E.

    1995-01-01

    Ulysses has collected data between 1 and 5 AU during, and just following solar maximum, when the heliospheric current sheet (HCS) can be thought of as reaching its maximum tilt and being subject to the maximum amount of turbulence in the solar wind. The Ulysses solar wind plasma instrument measures the vector velocity and can be used to estimate the flow speed and direction in turbulent 'eddies' in the solar wind that are a fraction of an astronomical unit in size and last (have either a turnover or dynamical interaction time of) several hours to more than a day. Here, in a simple exercise, these solar wind eddies at the HCS are characterized using Ulysses data. This character is then used to define a model flow field with eddies that is imposed on an ideal HCS to estimate how the HCS will be deformed by the flow. This model inherently results in the complexity of the HCS increasing with heliocentric distance, but the result is a measure of the degree to which the observed change in complexity is a measure of the importance of solar wind flows in deforming the HCS. By comparison with randomly selected intervals not located on the HCS, it appears that eddies on the HCS are similar to those elsewhere at this time during the solar cycle, as is the resultant deformation of the interplanetary magnetic field (IMF). The IMF deformation is analogous to what is often termed the 'random walk' of interplanetary magnetic field lines.

  17. SEERISK concept: Dealing with climate change related hazards in southeast Europe: A common methodology for risk assessment and mapping focusing on floods, drought, winds, heat wave and wildfire.

    NASA Astrophysics Data System (ADS)

    Papathoma-Koehle, Maria; Promper, Catrin; Glade, Thomas

    2014-05-01

    Southeast Europe is a region that suffers often from natural hazards and has experienced significant losses in the recent past due to extreme weather conditions and their side-effects (cold and heat waves, extreme precipitation leading to floods / flash floods, thunderstorms, extreme winds, drought and wildfires). SEERISK ("Joint Disaster Management Risk Assessment and Preparedness in the Danube macro-region") is a European funded SEE (Southeast Europe) project that aims at the harmonisation and consistency among risk assessment practices undertaken by the partner countries at various levels regarding climate change related disasters. A common methodology for risk assessment has been developed that offers alternatives in order to tackle the problem of limited data. The methodology proposes alternative steps for hazard and vulnerability assessment that, according to the data availability, range from detailed modelling to expert judgement. In the present study the common methodology has been adapted for five hazard types (floods, drought, winds, heat wave and wildfire) that are expected to be affected by climate change in the future and are relevant for the specific study areas. The last step will be the application of the methodology in six different case studies in Hungary, Romania, Bosnia, Bulgaria, Slovakia and Serbia followed by field exercises.

  18. Chikungunya Virus–Vector Interactions

    PubMed Central

    Coffey, Lark L.; Failloux, Anna-Bella; Weaver, Scott C.

    2014-01-01

    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed. PMID:25421891

  19. Heat transfer phase change paint test (OH-42) of a Rockwell International SSV orbiter in the NASA/LRC Mach 8 variable density wind tunnel

    NASA Technical Reports Server (NTRS)

    Jones, R.; Creel, T. R., Jr.; Lawing, P.; Quan, M.; Dye, W.; Cummings, J.; Gorowitz, H.; Craig, C.; Rich, G.

    1973-01-01

    Phase change paint tests of a Rockwell International .00593-scale space shuttle orbiter were conducted in the Langley Research Center's Variable Density Wind Tunnel. The test objectives were to determine the effects of various wing/underbody configurations on the aerodynamic heating rates and boundary layer transition during simulated entry conditions. Several models were constructed. Each varied from the other in either wing cuff radius, airfoil thickness, or wing-fuselage underbody blending. Two ventral fins were glued to the fuselage underside of one model to test the interference heating effects. Simulated Mach 8 entry data were obtained for each configuration at angles of attack ranging from 25 to 40 deg, and a Reynolds number variation of one million to eight million. Elevon, bodyflap, and rudder flare deflections were tested. Oil flow visualization and Schlieren photographs were obtained to aid in reducing the phase change paint data as well as to observe the flow patterns peculiar to each configuration.

  20. Forecasting Evaluation of WindSat in the Coastal Environment

    NASA Technical Reports Server (NTRS)

    Lee, Thomas F.; Bettenhausen, Mike H.; Hawkins, Jeffrey D.; Richardson, Kim; Jedlovec, Gary; Smith, Matt

    2012-01-01

    WindSat has demonstrated that measurements from polarimetric space-based microwave radiometers can be used to retrieve global ocean surface vector winds. Since the date of launch in 2003, substantial incremental improvements have been made to WindSat data processing, calibration, and retrieval algorithms. The retrievals now have higher resolution, improved wind vector ambiguity removal, and enhanced capability to represent high winds. Utilization of WindSat retrievals (wind vectors, total precipitable water, rainrate and sea surface temperature) will be demonstrated in the context of operational weather forecasting applications, especially the monitoring of topographically-forced winds. Examples will be presented from various parts of the world, including inland seas, midlatitude oceans, the tropics, and the United States. We will illustrate retrievals in extreme high- and extreme low-wind regimes, both of which can be problematic. Rain contamination will be addressed. We will include a comparison of WindSat vector maps to corresponding maps from the QuikScat scatterometer. We will discuss how near-realtime data from WindSat is being transitioned to specific offices within the National Weather Service.

  1. Quantifying the respective contribution of wind stress and diabatic forcing to decadal temperature changes and regional sea level trends over 1993-2010 based on ECCO solutions

    NASA Astrophysics Data System (ADS)

    Llovel, W.; Fukumori, I.; Wang, O.

    2013-12-01

    Since 1993 and based on satellite altimetry data, sea level trends display a large regional variability. Some regions experience a sea level rise (e.g., the west tropical Pacific Ocean, the subpolar north Atlantic Ocean...) whereas other regions experience a drop (e.g., the east tropical Pacific Ocean, golf of Alaska...). Those sea level trends appear to be steric in nature. Moreover, steric changes appear to be mainly thermosteric, although halosteric effects can reduce or enhance thermosteric changes in some specific regions (Stammer et al., 2013). Understanding and quantifying the processes involved in regional sea level changes are important tasks to better constrain and ascertain the physical processes involved in regional sea level changes and then, to improve predictions to anticipate potential impacts. In this study, we analyze the ocean heat content change and its origin by analyzing Estimating the Circulation and Climate of the Ocean estimates (ECCO, Wunsch et al., 2009). We run numerical experiments to estimate and quantify the respective contribution of each atmospheric forcing (e.g., wind stress and diabatic forcing) to heat content change and regional sea level trends.

  2. Long-term variations of the solar wind parameters and their geoeffciency

    NASA Astrophysics Data System (ADS)

    Makarova, Liudmila; Shirochkov, Alexander

    One of the contradictory problems of the contemporary state of the solar-terrestrial physics is impact of the solar activity of different kinds on the near-Earth space. For a long time solar activity having cyclical variations of sunspots and solar flares were considered as a main factor in the study of the solar - terrestrial links. State of the solar wind, which depends on the processes occurring in the Sun, is an important indicator of the solar - terrestrial links. Right now geoeffeciency of the solar wind influence on the processes in the near-Earth space is commonly accepted fact. In this paper we study the long-term variations in the solar wind parameters using satellite data from 1966 to 2013. So, sporadic variability associated with casual short-term disturbances in the solar wind were excluded from consideration. We analyzed annual values of such parameters as the solar wind interplanetary field full magnetic vector (B), speed (V) and density (n), as well as its dynamic pressure (nV2). It was confirmed that in the long term variations of the total magnetic field vector B coincides with cyclic variability of the number of sunspots. The long-term variations in the solar wind velocity clearly demonstrated maximum at decreasing phase of solar activity cycle. Solar wind density values were minimal at the maxima of solar activity cycles and they increased in the decay phase of the cyclic activity. These results were mentioned in the previous literature. The new fact was that the density of the solar wind has increased from cycle to cycle from 1966 to 1993, and it began to decrease values after 1996. Dynamic pressure of the solar wind from 1966 to 1993 increased in proportion to the density of the solar wind. It was also found that since 1998 the dynamic pressure is determined of the total magnetic field vector IMF and the solar wind velocity. Analysis of long-term variations of ionospheric parameters at F region showed a high correlation with the values of

  3. Association of anthropogenic land use change and increased abundance of the Chagas disease vector Rhodnius pallescens in a rural landscape of Panama.

    PubMed

    Gottdenker, Nicole L; Calzada, José E; Saldaña, Azäel; Carroll, C Ronald

    2011-01-01

    Anthropogenic disturbance is associated with increased vector-borne infectious disease transmission in wildlife, domestic animals, and humans. The objective of this study was to evaluate how disturbance of a tropical forest landscape impacts abundance of the triatomine bug Rhodnius pallescens, a vector of Chagas disease, in the region of the Panama Canal in Panama. Rhodnius pallescens was collected (n = 1,186) from its primary habitat, the palm Attalea butyracea, in five habitat types reflecting a gradient of anthropogenic disturbance. There was a high proportion of palms infested with R. pallescens across all habitat types (range = 77.1-91.4%). Results show that disturbed habitats are associated with increased vector abundance compared with relatively undisturbed habitats. Bugs collected in disturbed sites, although in higher abundance, tended to be in poor body condition compared with bugs captured in protected forest sites. Abundance data suggests that forest remnants may be sources for R. pallescens populations within highly disturbed areas of the landscape.

  4. Wind Turbines Adaptation to the Variability of the Wind Field

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    including combined RF-acoustic antenna installed coaxially with the gondola of the wind power turbine. The work of the technique is synchronized with rotation of blades to eliminate their shielding action. Dangerous in terms of dynamic strength is the wind load pulse, the rise time which is comparable with the period of the natural frequency of the wind turbine elements (blade, tower, rotor, etc.). The amplitude decay of resonant vibrations at critical values of the speed of rotation can be realized through the use of mechanical elastic supports with nonlinear artificial dampers. They have a high coefficient of resistance, but may cause self-excited oscillations. We propose the way to deal with raised vibration of wind turbine elements at the expense of short-term increase of damping in the range of critical rotary axis speeds or during impulsive effects of wind loadings (wind gusts). This is possible through the use of non-linear electromagnetic dampers or active magnetic bearings. Their feature is the possibility of varying the mechanical stiffness and damping properties by changing the electrical parameters of electromagnets. The controlling of these parameters is carried out by the control system (CS) with the information feedback on the spatial-temporal structure of the wind field obtained from IRASS. In the composition of the CS can also be included the rotational speed sensor of the WPT rotor. This approach to the adaptation of wind turbines will allow to reduce vibration and to perform early compensation of the load on their components, which arise under the wind gusts. In addition, corrections about the wind field obtained with IRASS, would increase the mean power of WPT.

  5. Winds of Change: Expanding the Frontiers of Flight. Langley Research Center's 75 Years of Accomplishment, 1917-1992

    NASA Technical Reports Server (NTRS)

    Schultz, James

    1992-01-01

    This commemorative volume highlights in pictures and text seventy five years of accomplishments of the Langley Research Center. The introductory matter features wind tunnels and their contribution to the development of aeronautics. A chronological survey details four different periods in Langley's history. The first period, 1917-1939, is subtitled 'Perfecting the Plane' which details Langley's contribution to early aeronautics with examples from specific aircraft. The second period, 1940-1957, focuses on the development of military aircraft during and after World War II. The third period, 1958-1969, tells the story of Langley's involvement with NASA and the satellite and Apollo era. The fourth period, entitled 'Charting New Courses: 1970-1992 and Beyond', treats various new topics from aerospace planes to Mars landing, as well as older topics such as the Space Shuttle and research spinoffs.

  6. Changes in fish communities on a small spatial scale, an effect of increased habitat complexity by an offshore wind farm.

    PubMed

    van Hal, R; Griffioen, A B; van Keeken, O A

    2017-01-31

    The number of offshore wind farms (OWF) is increasing to meet the demands for renewable energy. The piles and hard substrate surrounding these piles creates new habitat for species with preference to hard substrates. We studied the impact of this hard substrate on the fish community in a Dutch OWF in the sandy southern North Sea, which had been in operation for five years. Multi-mesh gillnets were placed near the OWF structures on the hard substrate protection revetments and on the sandy bottom in the middle of the farm. The catches indicated attraction of cod, pouting, bullrout and edible and velvet crab, while attraction to the sandy habitat was shown for flatfish and whiting. Further, two species previously not caught in this area, goldsinny wrasse and grey trigger fish, were caught on the hard substrate. In addition a Dual-Frequency Identification Sonar (DIDSON) was used to record transects through the farm to observe individual fish in the water column throughout the farm and very near the OWF structures. High abundances of fish near the structure were observed during some days, while during other days equal distribution of fish in the area was observed. The area around the structures is thus only used temporarily for shelter or feeding. The DIDSON also allowed looking at the aggregation level of the fish. Seasonally the aggregation level differed most likely due to different species occurring in the area. In April, most fish were aggregated in schools, while in summer most observations were individual fish or loose aggregations. The wind farm structures had limited effect on the aggregation level compared to season or weather conditions.

  7. Doubly Fed Induction Machine Control For Wind Energy Conversion System

    DTIC Science & Technology

    2009-06-01

    Induction Generator (DFIG), Voltage Source Inverter (VSI), Space Vector Modulation (SVM), Wind Turbine, Field Programmable Gate Array ( FPGA ), Wind...basics of using a doubly-fed induction generator (DFIG) to convert the mechanical energy of the wind into useful electrical power that can be used to...thesis covers the basics of using a doubly-fed induction generator (DFIG) to convert the mechanical energy of the wind into useful electrical power

  8. Wind sensor

    NASA Technical Reports Server (NTRS)

    Stephens, J. B.; Laue, E. G. (Inventor)

    1976-01-01

    An apparatus is described for sensing the temperature, velocity, and direction of the wind, including four temperature-dependent crystal oscillators spaced about an axis, a heater centered on the axis, and a screen through which the wind blows to pass over the crystals. In one method of operation, the frequency of the oscillators is taken when the heater is not energized, to obtain the temperature of the wind, and the frequencies of the oscillators are taken after the heater is energized to determine the direction and velocity of the wind. When the heater is energized, the wind causes the downwind crystals to achieve a higher temperature than the upwind crystals, and with the magnitude of the difference indicating the velocity of the wind.

  9. Automated mesoscale winds determined from satellite imagery

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A new automated technique for extracting mesoscale fields from GOES visible/infrared satellite imagery was developed. Quality control parameters were defined to allow objective editing of the wind fields. The system can produce equivalent or superior cloud wind estimates compared to the time consuming manual methods used on various interactive meteorological processing systems. Analysis of automated mesoscale cloud wind for a test case yields an estimated random error value one meter per second and produces both regional and mesoscale vector wind field structure and divergence patterns that are consistent in time and highly correlated with subsequent severe thunderstorm development.

  10. The Analysis of Wind Seismic Noise and Algorithms of its Determination

    NASA Astrophysics Data System (ADS)

    Kislov, K. V.; Gravirov, V. V.; Labuncov, M.

    2010-12-01

    Main barrier on a way of increase quality of seismic observations is the noise oscillations of a ground owing to influence of parameters variations of an environment, which is exhibited in the broad band record. For a reduction of noise influences changes any of an environment parameter, its variations are noted. It serves for hardware or program compensation of the noise. Nowadays the numerous ways are developed for a noise level reduction made by changes of temperature, magnetic field and atmospheric pressure. It is not so difficult to conduct record-keeping of influence of ground waters level and snow coverage on long and super long periods also. Wind is high-power factor for noise producing. It was multiply noted in the scientific literature. The wind is connected to pressure, but it is not the same. The apart from of a gradient of pressure, on a field of a wind in a surface layer renders influence of the Coriolis force and friction about a surface of ground. Any obstacle, from small-scale (building, trees, wood bands and so on) up to large-scale (range of mountains), standing on a way of air flow, distorts a field of a wind. Therefore, there are zones of a wind strengthening, zone of wind shadow. It forms exposed to the wind and lee-side vortexes. The speed and the direction of the wind are influenced also by non-irregularity of vertical distribution temperature, which makes horizontal flows of an air influencing to underlying layers known as the phenomenon of turbulent viscosity. The wind has a character of a laminar flow only at low speeds. The vortexes formed by strengthening of the wind act quasi-periodic on an underlying surface, the force and period of these effects, including wind impacts in obstacles, grow with strengthening of a wind. It is size the same order, as acceleration created in atmosphere by barometric gradients. A very complex picture of seismic noise for each seismic station is created by outcome of air friction about the earth surface and

  11. Rotations with Rodrigues' Vector

    ERIC Educational Resources Information Center

    Pina, E.

    2011-01-01

    The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…

  12. Long-Term Wind Power Variability

    SciTech Connect

    Wan, Y. H.

    2012-01-01

    The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

  13. Late Pleistocene aeolian dust provenances and wind direction changes reconstructed by heavy mineral analysis of the sediments of the Dehner dry maar (Eifel, Germany)

    NASA Astrophysics Data System (ADS)

    Römer, Wolfgang; Lehmkuhl, Frank; Sirocko, Frank

    2016-12-01

    The study presents the results of a heavy mineral analysis from a 38 m long record of lacustrine Eifel maar sediments from a core section of the Dehner dry maar. The record encompasses the period from 29,000 to about 12,500 b2k. Statistical analyses enabled the distinction of local and regional source areas of aeolian material and revealed pronounced changes in the amounts of different heavy mineral species and corresponding changes in the grain size Index (GSI and CSI). The results indicate that during the early stages of MIS2 (39 to 30 m depth) aeolian sediments were supplied mostly from local sources. This period is characterized by low GSI and CSI ratios resulting from a reduced mobility of material due to a vegetation cover. The period between 23,000 and 12,900 b2k is characterized by a higher supply of heavy minerals from regional and more distant sources. Changes in the provenance areas are indicated in inverse relationships between zircon, rutile, tourmaline (ZRT) and carbonate particles. Shifts in the wind direction are documented in pronounced peaks of carbonate particles indicating easterly winds that have crossed the limestone basins in the Eifeler North South Zone. ZRT-group minerals on the other hand suggest a westerly source area from Palaeozoic clastic sedimentary rocks. The heavy mineral assemblage of the LGM section at 23,000 to 15,000 b2k displays a close correspondence with the stratigraphic relationships that have been obtained for the Landscape Evolution Zone 4 of the ELSA-Vegetation Stack of Sirocko et al. (2016). From the Heinrich 2 event onwards the analyses indicate an increasing degree of mixing of heavy minerals from various provinces. This suggests the existence of a presumably incomplete, thin cover of deflated loess-like sediments that has been repeatedly reworked on the elevated surfaces of the Eifel.

  14. Late Pleistocene aeolian dust provenances and wind direction changes reconstructed by heavy mineral analysis of the sediments of the Dehner dry maar (Eifel Mountains, Germany)

    NASA Astrophysics Data System (ADS)

    Lehmkuhl, Frank; Römer, Wolfgang; Sirocko, Frank

    2016-04-01

    The study presents the results of a heavy mineral analysis from a 38 m long record of aeolian sediments from a core section of the Dehner dry maar (Eifel Mountains, Germany). The record encompasses the period from 30 to about 12.5 ka. Heavy-mineral analysis of the silt fraction has been performed at a sampling interval of 1 m. Statistical analyses enabled the distinction of local and regional source areas of aeolian material and revealed pronounced changes in the amounts of different heavy mineral species and corresponding changes in the grain size index (GSI). The results indicate that during the early stages of MIS 2 (40 to 30m depth) aeolian sediments were supplied mostly from local sources. This period is characterized by a low GSI ratio resulting from a reduced mobility of material due to a vegetation cover. The climax of the LGM is characterized by a higher supply of heavy minerals from regional and more distant sources. Changes in the provenance areas are indicated in inverse relationships between zircon, rutile, tourmaline (ZRT) and carbonate particles. Shifts in the wind direction are documented in pronounced peaks of carbonate particles indicating easterly winds that have crossed the limestone basins in the Eifeler North South Zone. ZRT-group minerals on the other hand suggest a westerly source area and a supply from areas consisting of Paleozoic clastic sedimentary rocks. In the periods following the LGM the analyses indicate an increasing degree of mixing of heavy minerals from various provinces. This suggests the existence of a presumably incomplete, thin cover of deflatable loessic sediments that has been repeatedly reworked on the elevated surfaces of the Eifel.

  15. Vector independent transmission of the vector-borne bluetongue virus.

    PubMed

    van der Sluijs, Mirjam Tineke Willemijn; de Smit, Abraham J; Moormann, Rob J M

    2016-01-01

    Bluetongue is an economically important disease of ruminants. The causative agent, Bluetongue virus (BTV), is mainly transmitted by insect vectors. This review focuses on vector-free BTV transmission, and its epizootic and economic consequences. Vector-free transmission can either be vertical, from dam to fetus, or horizontal via direct contract. For several BTV-serotypes, vertical (transplacental) transmission has been described, resulting in severe congenital malformations. Transplacental transmission had been mainly associated with live vaccine strains. Yet, the European BTV-8 strain demonstrated a high incidence of transplacental transmission in natural circumstances. The relevance of transplacental transmission for the epizootiology is considered limited, especially in enzootic areas. However, transplacental transmission can have a substantial economic impact due to the loss of progeny. Inactivated vaccines have demonstrated to prevent transplacental transmission. Vector-free horizontal transmission has also been demonstrated. Since direct horizontal transmission requires close contact of animals, it is considered only relevant for within-farm spreading of BTV. The genetic determinants which enable vector-free transmission are present in virus strains circulating in the field. More research into the genetic changes which enable vector-free transmission is essential to better evaluate the risks associated with outbreaks of new BTV serotypes and to design more appropriate control measures.

  16. Wind Energy

    SciTech Connect

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

    2016-03-15

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

  17. A phytopathogenic fungus manipulates release of host plant odors causing behavioral changes to its symbiont and vector, the redbay ambrosia beetle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The redbay ambrosia beetle, Xyleborus glabratus, is the vector of a symbiotic fungus, Raffaelea lauricola that causes laurel wilt, a highly lethal disease to members of the Lauraceae. Pioneer Xyleborus glabratus beetles infect live trees with Raffaelea lauricola, and only when trees are declining be...

  18. Distribution of AAV8 particles in cell lysates and culture media changes with time and is dependent on the recombinant vector

    PubMed Central

    Piras, Bryan A; Drury, Jason E; Morton, Christopher L; Spence, Yunyu; Lockey, Timothy D; Nathwani, Amit C; Davidoff, Andrew M; Meagher, Michael M

    2016-01-01

    With clinical trials ongoing, efficient clinical production of adeno-associated virus (AAV) to treat large numbers of patients remains a challenge. We compared distribution of AAV8 packaged with Factor VIII (FVIII) in cell culture media and lysates on days 3, 5, 6, and 7 post-transfection and found increasing viral production through day 6, with the proportion of viral particles in the media increasing from 76% at day 3 to 94% by day 7. Compared to FVIII, AAV8 packaged with Factor IX and Protective Protein/Cathepsin A vectors demonstrated a greater shift from lysate towards media from day 3 to 6, implying that particle distribution is dependent on recombinant vector. Larger-scale productions showed that the ratio of full-to-empty AAV particles is similar in media and lysate, and that AAV harvested on day 6 post-transfection provides equivalent function in mice compared to AAV harvested on day 3. This demonstrates that AAV8 production can be optimized by prolonging the duration of culture post-transfection, and simplified by allowing harvest of media only, with disposal of cells that contain 10% or less of total vector yield. Additionally, the difference in particle distribution with different expression cassettes implies a recombinant vector-dependent processing mechanism which should be taken into account during process development. PMID:27069949

  19. Wind/Hybrid Electricity Applications

    SciTech Connect

    McDaniel, Lori

    2001-03-01

    Wind energy is widely recognized as the most efficient and cost effective form of new renewable energy available in the Midwest. New utility-scale wind farms (arrays of large turbines in high wind areas producing sufficient energy to serve thousands of homes) rival the cost of building new conventional forms of combustion energy plants, gas, diesel and coal power plants. Wind energy is not subject to the inflationary cost of fossil fuels. Wind energy can also be very attractive to residential and commercial electric customers in high wind areas who would like to be more self-sufficient for their energy needs. And wind energy is friendly to the environment at a time when there is increasing concern about pollution and climate change. However, wind energy is an intermittent source of power. Most wind turbines start producing small amounts of electricity at about 8-10 mph (4 meters per second) of wind speed. The turbine does not reach its rated output until the wind reaches about 26-28 mph (12 m/s). So what do you do for power when the output of the wind turbine is not sufficient to meet the demand for energy? This paper will discuss wind hybrid technology options that mix wind with other power sources and storage devices to help solve this problem. This will be done on a variety of scales on the impact of wind energy on the utility system as a whole, and on the commercial and small-scale residential applications. The average cost and cost-benefit of each application along with references to manufacturers will be given. Emerging technologies that promise to shape the future of renewable energy will be explored as well.

  20. The effect of sensor sheltering and averaging techniques on wind measurements at the Shuttle Landing Facility

    NASA Technical Reports Server (NTRS)

    Merceret, Francis J.

    1995-01-01

    This document presents results of a field study of the effect of sheltering of wind sensors by nearby foliage on the validity of wind measurements at the Space Shuttle Landing Facility (SLF). Standard measurements are made at one second intervals from 30-feet (9.1-m) towers located 500 feet (152 m) from the SLF centerline. The centerline winds are not exactly the same as those measured by the towers. A companion study, Merceret (1995), quantifies the differences as a function of statistics of the observed winds and distance between the measurements and points of interest. This work examines the effect of nearby foliage on the accuracy of the measurements made by any one sensor, and the effects of averaging on interpretation of the measurements. The field program used logarithmically spaced portable wind towers to measure wind speed and direction over a range of conditions as a function of distance from the obstructing foliage. Appropriate statistics were computed. The results suggest that accurate measurements require foliage be cut back to OFCM standards. Analysis of averaging techniques showed that there is no significant difference between vector and scalar averages. Longer averaging periods reduce measurement error but do not otherwise change the measurement in reasonably steady flow regimes. In rapidly changing conditions, shorter averaging periods may be required to capture trends.

  1. The changing influences of the AMO and PDO on the decadal variation of the Santa Ana winds

    NASA Astrophysics Data System (ADS)

    Li, Andy K.; Paek, Houk; Yu, Jin-Yi

    2016-06-01

    Santa Ana wind (SAW) events have great implications for the environment of Southern California, but the cause of their decadal variability has not been fully understood. We show with observational analysis that the Atlantic multi-decadal oscillation (AMO) has a stronger influence than the Pacific decadal oscillation (PDO) in modulating SAW activity through two mechanisms: the Great Basin pressure gradient mechanism, in which a strengthened Great Basin high promotes SAW activity and vice versa through the northeast-southwest pressure gradient across Southern California, and the Pacific jetstream displacement mechanism, in which a strengthened Pacific subtropical high (PSH) prohibits mid-latitude cyclones from traveling toward California, consequently encouraging SAW development and vice versa. While the AMO strengthens or weakens both the Great Basin and PSHs to strongly modulate SAW activity through these two mechanisms, the PDO strengthens one of the highs but weakens the other, causing the two mechanisms to cancel each other, producing little influence on SAW activity. A projection based on the AMO and PDO indicates that the above-average SAW activity observed since the beginning of the 21st century is likely to terminate after 2016, after which Southern California may experience an extended period of below-average SAW activity through 2030.

  2. Wind Farms and Weather Modification.

    NASA Astrophysics Data System (ADS)

    Barrie, D. B.; Kirk-Davidoff, D. B.

    2008-12-01

    Electrical generation by wind turbines is increasing rapidly, and has been projected to satisfy 15 percent of world electric demand by 2030. The extensive installation of wind farms would alter surface roughness and significantly impact the atmospheric circulation. This forcing could be changed deliberately by adjusting the attitude of the turbine blades with respect to the wind. Using the NCAR Community Atmosphere Model, we model the impact of time-dependent surface roughness changes due to manipulation of a continent-scale wind farm. We show that initial disturbances caused by a step change in roughness grow within four days such that the flow is altered at synoptic scales. The growth rate of the induced perturbations is largest in regions of high atmospheric instability. For a roughness change imposed over North America, the induced perturbations involve substantial changes in the track and development of cyclones over the North Atlantic. For example, in some cases, weather over the British Isles changes from cloudy to clear, depending on whether wind turbines in the American Midwest are "on" or "off" three days beforehand. We explore the dependence of the downstream effects on the size and roughness of the wind farm installation, showing that as the size of individual wind farms and turbines grows, the scale of atmospheric impacts increases in extent and magnitude. We also look at the dependence of the wind farm impacts on the initial state of the atmosphere, confirming that the impacts are largest when the wind farm perturbation projects onto growing error modes in the atmosphere. In particular, rapid growth occurs when the initial disturbance is carried into regions of high baroclinic instability such as the North Atlantic. By running ensemble experiments, we estimate the robustness of the wind farm impacts with respect to realistic uncertainty in the initial conditions. Our results suggest the possibility of a method for weather modification that in some

  3. Wind energy.

    PubMed

    Leithead, W E

    2007-04-15

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

  4. ValidWind applications: wind power prospecting, aerosol transport

    NASA Astrophysics Data System (ADS)

    Wilkerson, T.; Marchant, A.; Apedaile, T.; Scholes, D.; Simmons, J.; Bradford, B.

    2010-10-01

    The ValidWind™ system employs an XL200 laser rangefinder to track small, lightweight, helium-filled balloons (0.33 meters, 0.015 kg). We record their trajectories (range resolution 0.5 meters) and automatically produce local wind profiles in real time. Tracking range is enhanced beyond 2 km by applying retro-reflector tape to the balloons. Aerodynamic analysis shows that ValidWind balloon motion is well coupled to the local wind within relaxation times { 1 second, due to drag forces at subcritical Reynolds numbers Re < 2×105. Such balloons are Lagrangian sensors; i.e., they move with the wind as opposed to being fixed in space. In a field campaign involving many balloons, slight variations in ground level winds at launch lead to trajectory patterns that we analyze to derive 3D maps of the vertical and horizontal wind profiles downwind of the launch area. Field campaigns are focused on likely sites for wind power generation and on facilities from which airborne particulates are emitted. We describe results of wind measurements in Utah near the cities of Clarkston, Logan, and Ogden. ValidWind is a relatively inexpensive wind sensor that is easily and rapidly transported and deployed at remote sites. It is an ideal instrument for wind prospecting to support early decisions required, for example, in siting meteorology towers. ValidWind provides high-resolution, real time characterization of the average and changing 3D wind fields in which wind power turbines and other remote sensors must operate.

  5. VisibleWind: wind profile measurements at low altitude

    NASA Astrophysics Data System (ADS)

    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

  6. Electrodynamics, wind and temperature

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.

    1988-01-01

    This RTOP provides for correlative meteorological wind and temperature measurements with atmospheric electrodynamic measurements. Meteorological rocketsondes were launched as part of a number of electrodynamic investigations in Alaska, Norway, Peru, Sweden, and at the Wallops Flight Facility, Wallops Island, Virginia. Measurements obtained as part of the MAC/Epsilon campaign during October 1987 from Andoya, Norway, were in conjunction with electric field, ion mobility, conductivity, and energy deposition studies. The measurements obtained between 30 and 90 km are to evaluate and correlate changes in the atmospheric electrical structure caused by the neutral wind and temperature, or changes in the neutral atmosphere resulting from electrical anomalies.

  7. Extensive Replication of a Retroviral Replicating Vector Can Expand the A Bulge in the Encephalomyocarditis Virus Internal Ribosome Entry Site and Change Translation Efficiency of the Downstream Transgene.

    PubMed

    Lin, Amy H; Liu, Yanzheng; Burrascano, Cynthia; Cunanan, Kathrina; Logg, Christopher R; Robbins, Joan M; Kasahara, Noriyuki; Gruber, Harry; Ibañez, Carlos; Jolly, Douglas J

    2016-04-01

    We have developed retroviral replicating vectors (RRV) derived from Moloney murine gammaretrovirus with an amphotropic envelope and an encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES)-transgene cassette downstream of the env gene. During long-term (180 days) replication of the vector in animals, a bulge of 7 adenosine residues (A's) in the J-K bifurcation domain sometimes serially added A's. Therefore, vectors with 4-12 A's in the A bulge in the J-K bifurcation domain were generated, and the impact of the variants on transgene protein expression, vector stability, and IRES sequence upon multiple infection cycles was assessed in RRV encoding yeast-derived cytosine deaminase and green fluorescent protein in vitro. For transgene protein expression, after multiple infection cycles, RRV-IRES with 5-7 A's gave roughly comparable levels, 4 and 8 A's were within about 4-5-fold of the 6 A's, whereas 10 and 12 A's were marked lower. In terms of stability, after 10 infection cycles, expansion of A's appeared to be a more frequent event affecting transgene protein expression than viral genome deletions or rearrangement: 4 and 5 A's appeared completely stable; 6, 7, and particularly 8 A's showed some level of expansion in the A bulge; 10 and 12 A's underwent both expansion and transgene deletion. The strong relative translational activity of the 5 A's in the EMCV IRES has not been reported previously. The 5A RRV-IRES may have utility for preclinical and clinical applications where extended replication is required.

  8. Association of Anthropogenic Land Use Change and Increased Abundance of the Chagas Disease Vector Rhodnius pallescens in a Rural Landscape of Panama

    PubMed Central

    Gottdenker, Nicole L.; Calzada, José E.; Saldaña, Azäel; Carroll, C. Ronald

    2011-01-01

    Anthropogenic disturbance is associated with increased vector-borne infectious disease transmission in wildlife, domestic animals, and humans. The objective of this study was to evaluate how disturbance of a tropical forest landscape impacts abundance of the triatomine bug Rhodnius pallescens, a vector of Chagas disease, in the region of the Panama Canal in Panama. Rhodnius pallescens was collected (n = 1,186) from its primary habitat, the palm Attalea butyracea, in five habitat types reflecting a gradient of anthropogenic disturbance. There was a high proportion of palms infested with R. pallescens across all habitat types (range = 77.1–91.4%). Results show that disturbed habitats are associated with increased vector abundance compared with relatively undisturbed habitats. Bugs collected in disturbed sites, although in higher abundance, tended to be in poor body condition compared with bugs captured in protected forest sites. Abundance data suggests that forest remnants may be sources for R. pallescens populations within highly disturbed areas of the landscape. PMID:21212205

  9. Light axial vector mesons

    NASA Astrophysics Data System (ADS)

    Chen, Kan; Pang, Cheng-Qun; Liu, Xiang; Matsuki, Takayuki

    2015-04-01

    Inspired by the abundant experimental observation of axial-vector states, we study whether the observed axial-vector states can be categorized into the conventional axial-vector meson family. In this paper we carry out an analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial-vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial-vector mesons, which are valuable for further experimental exploration of the observed and predicted axial-vector mesons.

  10. Design of a nonlinear backstepping control strategy of grid interconnected wind power system based PMSG

    NASA Astrophysics Data System (ADS)

    Errami, Y.; Obbadi, A.; Sahnoun, S.; Benhmida, M.; Ouassaid, M.; Maaroufi, M.

    2016-07-01

    This paper presents nonlinear backstepping control for Wind Power Generation System (WPGS) based Permanent Magnet Synchronous Generator (PMSG) and connected to utility grid. The block diagram of the WPGS with PMSG and the grid side back-to-back converter is established with the dq frame of axes. This control scheme emphasises the regulation of the dc-link voltage and the control of the power factor at changing wind speed. Besides, in the proposed control strategy of WPGS, Maximum Power Point Tracking (MPPT) technique and pitch control are provided. The stability of the regulators is assured by employing Lyapunov analysis. The proposed control strategy for the system has been validated by MATLAB simulations under varying wind velocity and the grid fault condition. In addition, a comparison of simulation results based on the proposed Backstepping strategy and conventional Vector Control is provided.

  11. Moist wind relationships

    NASA Technical Reports Server (NTRS)

    Raymond, William H.

    1990-01-01

    The equations describing the temporal and spatial behavior of the kinematic moisture and heat flux are described. In these nonlinear equations, the contribution by diabatic processes to the large-scale flux is composed of two parts. One part is associated with a Rayleigh damping term while the other arises from temporal and spatial changes in the pressure gradient term. It was found that the influence of diabatic processes on large-scale moisture fluxes depends greatly on the degree of balance between forcing and damping terms in the governing kinematic flux equations. The existence of a near balance requires a reduction in the large-scale horizontal geostrophic wind speed. Based on an examination of the moisture flux equations, it is argued that reductions in the large-scale horizontal wind speed observed within major cumulus cloud systems help conserve large-scale moisture fluxes. The deviation of the wind from geostrophic conditions is easily estimated for a near balanced state. This wind modification induces secondary vertical circulations that contribute to convergence, creating or supporting long-lived mesoscale flows. We believe this process to be a major supporter of the mesoscale circulations observed in severe storms and squall lines. In the tropics the wind modification has an antitriptic relationship. These diagnostic findings suggest possible modifications to the wind field in the application of a cumulus parameterization, and may be important in diabatic initialization of numerical weather prediction models.

  12. Winds in the Thermosphere

    NASA Astrophysics Data System (ADS)

    Killeen, T. L.; Burns, A. G.

    2005-12-01

    T. L. Killeen and A. G. Burns Studies of thermospheric dynamics began in the middle 1960s, when King suggested that winds would flow from the hot afternoon sector into the cooler morning region. Later work showed that winds were also driven by the high latitude ion convection pattern and by waves propagating upwards from the lower atmosphere. Ground based Fabry-Perot Interferometers (FPIs) were soon developed that could measure these winds. These interferometers have been deployed successfully both at a variety of ground based locations and in space. Other types of instruments, such as the DE-FPI, WATS and the WINDII instruments, have been deployed successfully in space. The development of thermospheric general circulation models (GCMs) has also greatly increased our understanding of the dynamics of the thermosphere and the way that these dynamics develop as forcing changes. Recent developments include thermosphere-ionosphere GCMs that are coupled with the magnetosphere and improved empirical wind models. In this presentation we summarize the history of thermospheric dynamics. In addition, we discuss current developments with reference to some new, coupled model results that show a number of unexpected features such as strong vertical gradients of horizontal winds in certain conditions and a complex morphology of the dawn convection pattern. Lastly, we suggest some future directions for investigations of the winds in the thermosphere.

  13. Study of Trade Wind Clouds Using Ground Based Stereo Cameras

    NASA Astrophysics Data System (ADS)

    Porter, J.

    2010-12-01

    We employ ground based stereo cameras to derive the three dimensional position of trade wind clouds features. The process employs both traditional and novel methods. The stereo cameras are calibrated for orientation using the sun as a geo-reference point at several times throughout the day. Spatial correlation is used to detect similar cloud features in both camera images and a simultaneous-differential equation is solved to get the best cloud position for the given rays from the cameras to the cloud feature. Once the positions of the clouds are known in three-dimensional space, then it is also possible to derive upper level wind speed and direction by tracking the position of clouds in space and time. The vector winds can be obtained at many locations and heights in a cone region over the surface site. The accuracy of the measurement depends on the camera separation with a trade-off occurring at different camera separations and cloud ranges. The system design and performance will be discussed along with field observations. This approach provides a new way to study clouds for climate change efforts. It also provides an inexpensive way to measure upper level wind fields in cloudy regions. Ground based stereo cameras are used to derive cloud position in space a time.

  14. Stellar Winds

    NASA Astrophysics Data System (ADS)

    Owocki, Stan

    A "stellar wind" is the continuous, supersonic outflow of matter from the surface layers of a star. Our sun has a solar wind, driven by the gas-pressure expansion of the hot (T > 106 K) solar corona. It can be studied through direct in si