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. Analysis of vector wind change with respect to time for Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1978-01-01

    A statistical analysis of the temporal variability of wind vectors at 1 km altitude intervals from 0 to 27 km altitude taken from a 10-year data sample of twice-daily rawinsode wind measurements over Vandenberg Air Force Base, California is presented.

  4. Vector wind profile gust model

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.; Smith, O. E.

    1981-01-01

    The development of a vector wind gust model that is suitable for orbital flight test operations and trade studies was studied. Verification of the hypothesis that gust component variables are gamma distributed, gust modulus is approximately Weibull distributed, and zonal and meridional gust components are bivariate gamma distributed is emphasized. A method of testing for bivariate gamma distributed variables, and two distributions for gust modulus are described. The results of extensive hypothesis testing of one of the distributions are presented, and the validity of the gamma distribution for representation of gust component variables is established.

  5. 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.

  6. 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.

  7. 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.

  8. Vector wind profile gust model

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1983-01-01

    A five parameter gamma distribution (BGD) having two shape parameters, two location parameters, and a correlation parameter is investigated. This general BGD is expressed as a double series and as a single series of the modified bessel function, and reduces to the known special case for equal shape parameters. Practical functions for computer evaluations for the general BGD and for special cases are presented. Applications are to be bound in reliability theory, signal noise, and meteorology. Applications to wind gust modeling for the ascent flight of the space shuttle are illustrated.

  9. 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.

  10. Wind Streak Changes

    NASA Technical Reports Server (NTRS)

    2004-01-01

    2 September 2004 This pair of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images shows changes in dark wind streak patterns that occurred between 5 April 1999 (image M00-00534) and 17 August 2004 (image R20-00901). Unlike the spaghetti-like streak patterns made by dust devils, these streaks all begin on their upwind ends as tapered forms that fan outward in the downwind direction, and they all indicate winds that blew from the same direction. In both cases, winds blew from the southeast (lower right) toward the northwest (upper left). These streaks and the small pedestal craters found among them occur in the Memnonia region of Mars near 5.9oS, 162.2oW. The 400 meter scale bar is about 437 yards long. Sunlight illuminates each scene from the upper left.

  11. Rapid Temporal Changes of Boundary Layer Winds

    NASA Technical Reports Server (NTRS)

    Merceret, Francis J.

    2005-01-01

    The statistical distribution of the magnitude of the vector wind change over 0.25, 0.5, 1 and 2-h periods based on data from November 1999 through August 2001 is presented. The distributions of the 2-h u and v component wind changes are also presented for comparison. The wind changes at altitudes from 500 to 3000 m were measured using the Eastern Range network of five 915 MHz Doppler radar wind profilers. Quality controlled profiles were produced every 15 minutes for up to sixty gates, each representing 101 m in altitude over the range from 130 m to 6089 m. Five levels, each constituting three consecutive gates, were selected for analysis because of their significance to aerodynamic loads during the Space Shuttle ascent roll maneuver. The distribution of the magnitude of the vector wind change is found to be lognormal consistent with earlier work in the mid-troposphere. The parameters of the distribution vary with time lag, season and altitude. The component wind changes are symmetrically distributed with near-zero means, but the kurtosis coefficient is larger than that of a Gaussian distribution.

  12. 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...

  13. An improved hurricane wind vector retrieval algorithm using SeaWinds scatterometer

    NASA Astrophysics Data System (ADS)

    Laupattarakasem, Peth

    Over the last three decades, microwave remote sensing has played a significant role in ocean surface wind measurement, and several scatterometer missions have flown in space since early 1990's. Although they have been extremely successful for measuring ocean surface winds with high accuracy for the vast majority of marine weather conditions, unfortunately, the conventional scatterometer cannot measure extreme winds condition such as hurricane. The SeaWinds scatterometer, onboard the QuikSCAT satellite is NASA's only operating scatterometer at present. Like its predecessors, it measures global ocean vector winds; however, for a number of reasons, the quality of the measurements in hurricanes are significantly degraded. The most pressing issues are associated with the presence of precipitation and Ku-band saturation effects, especially in extreme wind speed regime such as tropical cyclones (hurricanes and typhoons). Under this dissertation, an improved hurricane ocean vector wind retrieval approach, named as Q-Winds, was developed using existing SeaWinds scatterometer data. This unique data processing algorithm uses combined SeaWinds active and passive measurements to extend the use of SeaWinds for tropical cyclones up to approximately 50 m/s (Hurricane Category-3). Results show that Q-Winds wind speeds are consistently superior to the standard SeaWinds Project Level 2B wind speeds for hurricane wind speed measurement, and also Q-Winds provides more reliable rain flagging algorithm for quality assurance purposes. By comparing to H*Wind, Q-Winds achieves ˜9% of error, while L2B-12.5km exhibits wind speed saturation at ˜30 m/s with error of ˜31% for high wind speed (>40 m/s).

  14. 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.

  15. 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.

  16. 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

  17. 10 Years of Height Resolved, Cloud-Track, Vector Winds from MISR

    NASA Astrophysics Data System (ADS)

    Garay, M. J.; Mueller, K. J.; Moroney, C. M.; Jovanovic, V.; Wu, D. L.; Diner, D. J.

    2009-12-01

    By utilizing multiple camera views and fast image matching algorithms to identify common features and determine feature motion, the MISR instrument on NASA’s Terra satellite has now collected nearly 10 years of height-resolved, cloud-track, vector winds using a single, globally consistent algorithm. The MISR cloud-track winds are reported globally on mesoscale domains of 70.4 km × 70.4 km and referenced to stereoscopically derived heights above the earth ellipsoid, which have a nominal vertical resolution of approximately 500 m. Importantly, from the standpoint of climate research, the stereo height assignment and wind retrieval are largely insensitive to instrument calibration changes because the pattern matcher relies only on relative brightness values, rather than the absolute magnitude of the brightness. We will describe comparisons with other wind datasets, including geostationary cloud drift winds, scatterometer surface winds, and reanalysis model winds, that demonstrate the quality of the MISR winds. We will also show the coverage and resolution advantages that MISR provides relative to these other datasets. Additionally, because the global winds are driven primarily by the global (im)balance of heating, monitoring variations in the winds over 10 years promises to yield important insights into the processes related to the hydrologic cycle and transport of heat and water vapor, such as the Madden-Julian Oscillation (MJO) and the El Niño Southern Oscillation (ENSO).

  18. Study of wind change for the development of loads reduction techniques for the space shuttle

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1987-01-01

    Wind change statistics are analyzed for Vandenberg AFB, California (VAFB) and Kennedy Space Center, Florida (KSC). Means and standard deviations of wind component change and vector wind change modulus within 3-9 and 9-16 km altitude bands are tabulated. The contribution to 3.5 hr wind component change by wind perturbations in various wavelength bands is evaluated. Probability distributions of maximum 3.5 hr wind change in an altitude band are presented and a model for wind change at a specified altitude is tested with data derived from six data bases from VAFB and Santa Monica, California.

  19. Using Daily Ocean Wind Vector and Speed Measurements to Estimate the Diurnal Cycle Modes

    NASA Astrophysics Data System (ADS)

    Turk, F. J.; Hristova-Veleva, S. M.; Haddad, Z. S.

    2014-12-01

    Over many oceanic regions, the surface wind varies widely throughout the day, owing to various meteorological forcings, such as land/sea temperature differences near coasts, or variations associated with tropical precipitation processes. Over the tropical oceans, several coarsely spaced buoy networks (TAO/TRITON in the Pacific, PIRATA in the Atlantic, RAMA in the Indian Ocean) are maintained as part of the Global Tropical Moored Buoy Array. For finer global scale analysis, further improvements to the modeling and understanding of physical processes within the coupled atmosphere ocean is based upon analysis of a disparate collection of low Earth orbiting (LEO) satellite based ocean surface wind data records. Since LEO satellite observations represent intermittently spaced, instantaneous snapshots, sampling against the backdrop of continuously changing physical processes, its is important to carefully merge and analyze the multiple satellite datasets in order to extract meaningful information on diurnal and semi-diurnal wind cycles. Early analysis of an investigation are described whereby multi-year collections of global sun-synchronous and asynchronous orbiting satellite ocean wind data are used to investigate the diurnal and semi-diurnal ocean wind vector variability over certain regions. A unique feature of the effort is the utilization of all capable sensors, including both wind speed and wind vector capable sensors, using overlapping asynchronous satellite observations to establish self-consistency, including inter-sensor bias correction to a common reference platform.

  20. 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. PMID:24044652

  1. 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.

  2. Numerical study of 1-D, 3-vector component, thermally-conductive MHD solar wind

    NASA Technical Reports Server (NTRS)

    Han, S.; Wu, S. T.; Dryer, M.

    1993-01-01

    In the present study, transient, 1-dimensional, 3-vector component MHD equations are used to simulate steady and unsteady, thermally conductive MHD solar wind expansions between the solar surface and 1 AU (astronomical unit). A variant of SIMPLE numerical method was used to integrate the equations. Steady state solar wind properties exhibit qualitatively similar behavior with the known Weber-Davies Solutions. Generation of Alfven shock, in addition to the slow and fast MHD shocks, was attempted by the boundary perturbations at the solar surface. Property changes through the disturbance were positively correlated with the fast and slow MHD shocks. Alfven shock was, however, not present in the present simulations.

  3. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. Therefore 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 aeroelastic wing (53%), as well as sudden changes in wing loading (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 deviation) 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.

  4. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    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. Therefore 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.

  5. Fault diagnosis of direct-drive wind turbine based on support vector machine

    NASA Astrophysics Data System (ADS)

    An, X. L.; Jiang, D. X.; Li, S. H.; Chen, J.

    2011-07-01

    A fault diagnosis method of direct-drive wind turbine based on support vector machine (SVM) and feature selection is presented. The time-domain feature parameters of main shaft vibration signal in the horizontal and vertical directions are considered in the method. Firstly, in laboratory scale five experiments of direct-drive wind turbine with normal condition, wind wheel mass imbalance fault, wind wheel aerodynamic imbalance fault, yaw fault and blade airfoil change fault are carried out. The features of five experiments are analyzed. Secondly, the sensitive time-domain feature parameters in the horizontal and vertical directions of vibration signal in the five conditions are selected and used as feature samples. By training, the mapping relation between feature parameters and fault types are established in SVM model. Finally, the performance of the proposed method is verified through experimental data. The results show that the proposed method is effective in identifying the fault of wind turbine. It has good classification ability and robustness to diagnose the fault of direct-drive wind turbine.

  6. 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

  7. 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.

  8. 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. PMID:25222957

  9. 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. PMID:27260548

  10. 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.

  11. 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.

  12. The Dependence of Ocean Surface Emissivity on Wind Vector as Measured with TMR

    NASA Technical Reports Server (NTRS)

    Tran, N.; Vandemark, D.; Ruf, C.; Zukor, Dorothy (Technical Monitor)

    2000-01-01

    Global TMR brightness temperature observations at 18, 21, and 37 GHz have been colocated with near-simultaneous SeaWinds wind vector data as well as with a monthly SST climatological product. The combined data allow us to study the dependence of ocean surface emissivity, at each frequency, upon both wind speed and direction. Results show a clear two-branch wind speed dependence; weak and linear below 6 m/s with an abrupt increase in sensitivity above that point. Our analysis also shows that the nadir-view ocean surface emissivity depends on the angle between the wind direction and TMR's antenna polarization orientation.

  13. Comparison Of High Winds Retrieved From RADARSAT 2 SAR Data With In Situ Buoy Data And QuikScat Wind Vectors

    NASA Astrophysics Data System (ADS)

    Xie, Tao; Perrie, Will

    2010-04-01

    Selected SAR images of high wind speeds have been obtained from RADARSAT-2 co-located with in situ observations from the HurricaneWatch program. In this presentation we use these RADARSAT-2 SAR images to retrieve ocean surface wind speeds, using CMOD_IFR, and modified algorithms. We compare these SAR- derived winds with in situ buoy data and QuikScat wind vectors. Results shows that SAR-derived wind speeds from CMOD5 are closer to the in situ buoy wind speeds than CMOD_IFR2 or CMOD4 winds. Moreover, these SAR-derived wind speeds are underestimates of the actual wind fields, especially in high wind conditions, whereas QuikScat wind vectors are overestimates. We also find that the wind speed discrepancies between buoy measurements and SAR-derived winds occurring in unstable atmosphere boundary conditions may be larger than those occurring in stable conditions.

  14. Changes in Ocean Wind Retrieval Performance During the WindSat Mission

    NASA Astrophysics Data System (ADS)

    Bettenhausen, M. H.; Gaiser, P. W.; Adams, I. S.; Truesdale, D.

    2014-12-01

    Numerous improvements have been made to WindSat ground data processing software and retrieval algorithms since the initial evaluations of WindSat capabilities were published in 2006. These improvements include higher resolution retrievals, improved wind vector ambiguity selection, improved instrument characterization, better brightness temperature calibration and improved high wind speed retrievals. We briefly describe some of these improvements and provide statistical comparisons of the current WindSat ocean vector wind products to the older versions of the WindSat products. We also present comparisons for individual wind fields including examples of gap wind events and cyclonic storms. Limitations of the WindSat products and the underlying causes such as resolution and rain effects will be discussed.

  15. Climate Change: Potential Affect on Pesticide Application for Vector Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global climate change has and will in the future contribute to the global burden of vector-borne disease by affecting the spatial and tempral distribution of disease. These changes in disease distributions are a direct result of altering the ecology of immature and adult habitats of insect vectors....

  16. 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.

  17. 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.

  18. 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.

  19. Short-interval SMS wind vector determinations for a severe local storms area

    NASA Technical Reports Server (NTRS)

    Peslen, C. A.

    1980-01-01

    Short-interval SMS-2 visible digital image data are used to derive wind vectors from cloud tracking on time-lapsed sequences of geosynchronous satellite images. The cloud tracking areas are located in the Central Plains, where on May 6, 1975 hail-producing thunderstorms occurred ahead of a well defined dry line. Cloud tracking is performed on the Goddard Space Flight Center Atmospheric and Oceanographic Information Processing System. Lower tropospheric cumulus tracers are selected with the assistance of a cloud-top height algorithm. Divergence is derived from the cloud motions using a modified Cressman (1959) objective analysis technique which is designed to organize irregularly spaced wind vectors into uniformly gridded wind fields. The results demonstrate the feasibility of using satellite-derived wind vectors and their associated divergence fields in describing the conditions preceding severe local storm development. For this case, an area of convergence appeared ahead of the dry line and coincided with the developing area of severe weather. The magnitude of the maximum convergence varied between -10 to the -5th and -10 to the -14th per sec. The number of satellite-derived wind vectors which were required to describe conditions of the low-level atmosphere was adequate before numerous cumulonimbus cells formed. This technique is limited in areas of advanced convection.

  20. 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.

  1. A Vector Control for Grid-connected Wind Power Generation with Doubly Fed Induction Generator

    NASA Astrophysics Data System (ADS)

    Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

    Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation due to high efficiently for wind energy capture. An inverter system is required to control wind turbine speed and power factor in those generators. The inverter rating of the synchronous generator equals to generator rating. However, DFIG has the advantage that the inverter rating is about 25% to the generator rating. The paper describes a vector control of DFIG inter-connected to power line. The performance of proposed vector control is examined using power system simulation software PSCAD/EMTDC for the DFIG inter-connected to 6.6kv distribution line. The results show good dynamic responses and high accuracy to the stator active power control and the stator reactive power control.

  2. Scanning wind-vector scatterometers with two pencil beams

    NASA Technical Reports Server (NTRS)

    Kirimoto, T.; Moore, R. K.

    1984-01-01

    A scanning pencil-beam scatterometer for ocean windvector determination has potential advantages over the fan-beam systems used and proposed heretofore. The pencil beam permits use of lower transmitter power, and at the same time allows concurrent use of the reflector by a radiometer to correct for atmospheric attenuation and other radiometers for other purposes. The use of dual beams based on the same scanning reflector permits four looks at each cell on the surface, thereby improving accuracy and allowing alias removal. Simulation results for a spaceborne dual-beam scanning scatterometer with a 1-watt radiated power at an orbital altitude of 900 km is described. Two novel algorithms for removing the aliases in the windvector are described, in addition to an adaptation of the conventional maximum likelihood algorithm. The new algorithms are more effective at alias removal than the conventional one. Measurement errors for the wind speed, assuming perfect alias removal, were found to be less than 10%.

  3. Global change and human vulnerability to vector-borne diseases.

    PubMed

    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

  4. 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

  5. Angular Distribution of Solar Wind Magnetic Field Vector at 1 AU

    NASA Astrophysics Data System (ADS)

    Xu, F.; Li, G.; Zhao, L.; Zhang, Y.; Khabarova, O.; Miao, B.; le Roux, J.

    2015-03-01

    We study the angular distribution of the solar wind magnetic field vector at 1 AU and its solar cycle dependence using ACE observations. A total of twelve 27.27 day (the duration of a solar rotation) intervals during the solar maximum, the solar minimum, as well as the ascending and descending phases of solar cycle 23 are examined. For all selected intervals, we obtain the angular distribution function {{f}τ }(α ), where α is the angle between the instantaneous solar wind magnetic field vector and the average background magnetic field vector, and τ is the period length for the averaging. Our results show that in all periods {{f}τ }(α ) has two populations, one at small angles and one at large angles. We suggest that the second population is due to the presence of current sheets in the solar wind. The solar-cycle dependence of {{f}τ }(α ) and a τ-scaling property of the second population of {{f}τ }(α ) are discussed. The τ scaling shows a clear dependence on the solar wind type. The implication of {{f}τ }(α ) for particle acceleration at interplanetary shocks driven by coronal mass ejections, such as those in solar energetic particle events, is also discussed.

  6. 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

  7. [Vector transmitted diseases and climate changes in Europe].

    PubMed

    Rossati, Antonella; Bargiacchi, Olivia; Kroumova, Vesselina; Garavelli, Pietro Luigi

    2014-09-01

    The increase in temperatures recorded since the mid-nineteenth century is unprecedented in the history of mankind. The consequences of climate changes are numerous and can affect human health through direct (extreme events, natural disasters) or indirect (alteration of the ecosystem) mechanisms. Climate changes have repercussions on ecosystems, agriculture, social conditions, migration, conflicts and the transmission mode of infectious diseases. Vector-borne diseases are infections transmitted by the bite of infected arthropods such as mosquitoes, ticks, triatomines, sand flies and flies. Epidemiological cornerstones of vector-borne diseases are: the ecology and behaviour of the host, the ecology and behaviour of the vector, and the population's degree of immunity. Mosquito vectors related to human diseases mainly belong to the genus Culex, Aedes and Mansonia. Climate changes in Europe have increased the spread of new vectors, such as Aedes albopictus, and in some situations have made it possible to sustain the autochthonous transmission of some diseases (outbreak of Chukungunya virus in northern Italy in 2007, cases of dengue in the South of France and in Croatia). Despite the eradication of malaria from Europe, anopheline carriers are still present, and they may allow the transmission of the disease if the climatic conditions favour the development of the vectors and their contacts with plasmodium carriers. The tick Ixodes ricinus is a vector whose expansion has been documented both in latitude and in altitude in relation to the temperature increase; at the same time the related main viral and bacterial infections have increased. In northern Italy and Germany, the appearance of Leishmaniasis has been associated to climatic conditions that favour the development of the vector Phlebotomus papatasi and the maturation of the parasite within the vector, although the increase of cases of visceral leishmaniasis is also related to host immune factors, particularly

  8. Common themes in changing vector-borne disease scenarios.

    PubMed

    Molyneux, David H

    2003-01-01

    The impact of climate change on disease patterns is controversial. However, global burden of disease studies suggest that infectious diseases will contribute a proportionately smaller burden of disease over the next 2 decades as non-communicable diseases emerge as public health problems. However, infectious diseases contribute proportionately more in the poorest quintile of the population. Notwithstanding the different views of the impact of global warming on vector-borne infections this paper reviews the conditions which drive the changing epidemiology of these infections and suggests that such change is linked by common themes including interactions of generalist vectors and reservoir hosts at interfaces with humans, reduced biodiversity associated with anthropogenic environmental changes, increases in Plasmodium falciparum: P. vivax ratios and well-described land use changes such as hydrological, urbanization, agricultural, mining and forest-associated impacts (extractive activities, road building, deforestation and migration) which are seen on a global scale. PMID:14584362

  9. An unsupervised support vector method for change detection

    NASA Astrophysics Data System (ADS)

    Bovolo, F.; Camps-Valls, G.; Bruzzone, L.

    2007-10-01

    This paper formulates the problem of distinguishing changed from unchanged pixels in remote sensing images as a minimum enclosing ball (MEB) problem with changed pixels as target class. The definition of the sphere shaped decision boundary with minimal volume that embraces changed pixels is approached in the context the support vector formalism adopting a support vector domain description (SVDD) one-class classifier. The SVDD maps the data into a high dimensional feature space where the spherical support of the high dimensional distribution of changed pixels is computed. The proposed formulation of the SVDD uses both target and outlier samples for defining the MEB, and is included here in an unsupervised system for change detection. For this purpose, nearly certain examples for the classes of both targets (i.e., changed pixels) and outliers (i.e., unchanged pixels) for training are identified based on thresholding the magnitude of spectral change vectors. Experimental results obtained on two different multitemporal and multispectral remote sensing images pointed out the effectiveness of the proposed method.

  10. Global climate change and vector-borne diseases

    USGS Publications Warehouse

    Ginsberg, H.S.

    2002-01-01

    Global warming will have different effects on different diseases because of the complex and idiosynchratic interactions between vectors, hosts, and pathogens that influence transmission dynamics of each pathogen. Human activities, including urbanization, rapid global travel, and vector management, have profound effects on disease transmission that can operate on more rapid time scales than does global climate change. The general concern about global warming encouraging the spread of tropical diseases is legitimate, but the effects vary among diseases, and the ecological implications are difficult to predict.

  11. 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.

  12. 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

  13. 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

  14. Wave-vector dependence of magnetic-turbulence spectra in the solar wind.

    PubMed

    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|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. PMID:20482101

  15. 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.

  16. 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

  17. 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. PMID:11274908

  18. 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.

  19. Combining TOPEX and SeaWinds Data to Refine Models for Ocean Surface Emissivity: Wind Vector Signatures at 18, 21 and 37 GHz

    NASA Technical Reports Server (NTRS)

    Vandemark, D.; Tran, N.; Ruf, C.; Vandemark, Douglas (Technical Monitor)

    2001-01-01

    TOPEX Microwave Radiometer (TMR) brightness temperature observations at 18, 21, and 37 GHz have been collocated with near-simultaneous SeaWinds wind vector data as well as with a monthly SST climatological product. The combined data set allows us to study the dependence of ocean surface emissivity (at each frequency) upon both wind speed. Results show clear two-branch wind speed dependence; weak and linear below 6 m/s with an abrupt increase in sensitivity above that point. The analysis also shows that the zenith-directed ocean surface emissivity is polarization dependent above wind speeds of 5-6 m/s with an azimuthal variation related to the wind direction. This last result accords with recent polarimetric radiometer observations collected from aircraft. Implications of these observations to water vapor retrieval algorithms, nadir-viewing polarimetry, and ocean emission modeling will be discussed.

  20. Early effects of climate change: do they include changes in vector-borne disease?

    PubMed

    Kovats, R S; Campbell-Lendrum, D H; McMichael, A J; Woodward, A; Cox, J S

    2001-07-29

    The world's climate appears now to be changing at an unprecedented rate. Shifts in the distribution and behaviour of insect and bird species indicate that biological systems are already responding to this change. It is well established that climate is an important determinant of the spatial and temporal distribution of vectors and pathogens. In theory, a change in climate would be expected to cause changes in the geographical range, seasonality (intra-annual variability), and in the incidence rate (with or without changes in geographical or seasonal patterns). The detection and then attribution of such changes to climate change is an emerging task for scientists. We discuss the evidence required to attribute changes in disease and vectors to the early effects of anthropogenic climate change. The literature to date indicates that there is a lack of strong evidence of the impact of climate change on vector-borne diseases (i.e. malaria, dengue, leishmaniasis, tick-borne diseases). New approaches to monitoring, such as frequent and long-term sampling along transects to monitor the full latitudinal and altitudinal range of specific vector species, are necessary in order to provide convincing direct evidence of climate change effects. There is a need to reassess the appropriate levels of evidence, including dealing with the uncertainties attached to detecting the health impacts of global change. PMID:11516383

  1. Ground-based remote sensing of wind vector and visibility: latest results from guideline development

    NASA Astrophysics Data System (ADS)

    Boesenberg, Jens; Danzeisen, Hans H.; Engelbart, Dirk; Fritzsche, Klaus; Klein, Volker; Muenkel, Christoph; Trickl, Thomas; Werner, Christian; Woppowa, Ljuba

    2001-12-01

    The guideline series VDI 3786 'Environmental meteorology; Meteorological measurements' is organized into several parts. The present guideline VDI 3786 Part 14 describes the determination of the three-dimensional wind vector using Doppler LIDAR ('LIght Detection and Ranging' or 'Light Identificaiton, Detection and Ranging'). The guideline refers to guideline VDI 3786 Part 2 with regard to the definition of the measurement variable wind and goes back to the guideline VDI 3786 Part 1 in considering the averaging time. Use is also made of the guideline VDI 3786 Part 8. Safety problems are not treated; reference may be made here to relevant Standards [VBG 93, DIN EN 60825-1]. Wind profiles in the atmospheric boundary layer yield a very important contribution also to the investigation of atmospheric exchange processes. The wind field in the atmospheric boundary layer is highly variable in spatial and temporal scales. For a few applications a more frequeent wind sensing is necessary, i.e. (1) on airports located in low level jet areas, (2) near chemical plants to get information of the transport of toxic gases from leakages, (3) for metrology in general to improve the weather forecast, (4) for environment protection purposes like dispersion studies. The following statements are valid for visibility measurements [visual range LIDAR (VDI 3786 Part 15)]: (1) Lidar can provide the same information of the visibility as conventional sensors, but in addition lidar will provide range resolved measurements. (2) It is possible to shrink a lidar down to the size of binoculars. (3) It is possible to measure local visibility with an eye- safe (class 1) lidar. (4) Layers can be detected up to 250 m distance in approximately 2 s even with a small size instrument.

  2. Assessment of NOAA Processed OceanSat-2 Scatterometer Ocean Surface Vector Wind Products

    NASA Astrophysics Data System (ADS)

    Chang, P.; Jelenak, Z.; Soisuvarn, S.

    2011-12-01

    The Indian Space Research Organization (ISRO) launched the Oceansat-2 satellite on 23 September 2009. Oceansat-2 carries a radar scatterometer instrument (OSCAT) capable of measuring ocean surface vector winds (OSVW) and an ocean color monitor (OCM), which will retrieve sea spectral reflectance. Oceansat-2 is ISRO's second in a series of satellites dedicated to ocean research. It will provide continuity to the services and applications of the Oceansat-1 OCM data along with additional data from a Ku-band pencil beam scatterometer. Oceansat-2 is a three-axis, body stabilized spacecraft placed into a near circular sun-synchronous orbit, at an altitude of 720 kilometers (km), with an equatorial crossing time of around 1200 hours. ISRO, the National Oceanic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA) and the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) share the common goal of optimizing the quality and maximizing the utility of the Oceansat-2 data for the benefit of future global and regional scientific and operational applications. NOAA, NASA and EUMETSAT have been collaboratively working with ISRO on the assessment and analysis of OSCAT data to help facilitate continuation of QuikSCAT's decade-long Ku-band scatterometer data record. NOAA's interests are focused on the utilization of OSCAT data to support operational weather forecasting and warning in the marine environment. OSCAT has the potential to significantly mitigate the loss of NASA's QuikSCAT, which has negatively impacted NOAA's marine forecasting and warning services. Since March 2011 NOAA has been receiving near real time OSCAT measurements via EumetSat. NOAA has developed its own OSCAT wind processor. This processor produces ocean surface vector winds with resolution of 25km. Performance of NOAA OSCAT product will and its availability to larger user community will be presented and discussed.

  3. Vegetation change detection for urban areas based on extended change vector analysis

    NASA Astrophysics Data System (ADS)

    Yu, Hui; Jia, Yonghong

    2006-10-01

    This study sought to develop a modified change vector analysis(CVA) using normalized multi-temporal data to detect urban vegetation change. Because of complex change in urban areas, modified CVA application based on NDVI and mask techniques can minify the effect of non-vegetation changes and improve upon efficiency to a great extent. Moreover, drawing from methods in Polar plots, the extended CVA technique measures absolute angular changes and total magnitude of perpendicular vegetation index (PVI) and two of Tasseled Cap indices (greenness and wetness). Polar plots summarized change vectors to quantify and visualize both magnitude and direction of change, and magnitude is applied to determine change pixels through threshold segmentation while direction is applied as pixel's feature to classifying change pixels through supervised classification. Then this application is performed with Landsat ETM+ imageries of Wuhan in 2002 and 2005, and assessed by error matrix, which finds that it could detect change pixels 95.10% correct, and could classify change pixels 91.96% correct in seven change classes through performing supervised classification with direction angles. The technique demonstrates the ability of change vectors in multiple biophysical dimensions to vegetation change detection, and the application can be trended as an efficient alternative to urban vegetation change detection and classification.

  4. 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

  5. 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.

  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. 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.

  8. Calibration Performance and Capabilities of the New Compact Ocean Wind Vector Radiometer System

    NASA Astrophysics Data System (ADS)

    Brown, S. T.; Focardi, P.; Kitiyakara, A.; Maiwald, F.; Montes, O.; Padmanabhan, S.; Redick, R.; Russell, D.; Wincentsen, J.

    2014-12-01

    The paper describes performance and capabilities of a new satellite conically imaging microwave radiometer system, the Compact Ocean Wind Vector Radiometer (COWVR), being built by the Jet Propulsion Laboratory (JPL) for an Air Force demonstration mission. COWVR is an 18-34 GHz fully polarimetric radiometer designed to provide measurements of ocean vector winds with an accuracy that meets or exceeds that provided by WindSat, but using a simpler design which has both calibration and cost advantages. Heritage conical radiometer systems, such as WindSat, AMSR, GMI or SSMI(S), all have a similar overall architecture and have exhibited significant intra-channel and inter-sensor calibration biases, due in part to the relative independence of the radiometers between the different polarizations and frequencies in the system. The COWVR system uses a broadband compact hybrid combining architecture and Electronic Polarization Basis Rotation to minimize the number of free calibration parameters between polarization and frequencies, as well as providing a definitive calibration reference from the modulation of the mean polarized signal from the Earth. This second calibration advantage arises because the sensor modulates the incoming polarized signal at the input antenna aperture in a known way based only on the instrument geometry which forces relative calibration consistency between the polarimetric channels of the sensor and provides a gain and offset calibration independent of a model or other ancillary data source, which has typically been a weakness in the calibration and inter-calibration of heritage microwave sensors. This paper will give a description of the COWVR instrument and an overview of the technology demonstration mission. We will discuss the overall calibration approach for this system, its advantages over existing systems and how many of the calibration issues that impact existing satellite radiometers can be eliminated in future operational systems based on

  9. 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.

  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. Methods of reducing wind power changes from large turbine arrays

    SciTech Connect

    Schlueter, R.; Dorsey, J.; Lotfalian, M.; Park, G.; Shayanfar, M.

    1983-06-01

    This paper discusses 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. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented to establish the factors concerning the wind turbine model and siting configuration that contribute to these variations. Detailed simulation results indicate more precisely how these factors can be exploited to minimize the WECS generation changes observed. 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.

  12. 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.

  13. 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

  14. Quantifying Changes in Intrinsic Molecular Motion Using Support Vector Machines.

    PubMed

    Leighty, Ralph E; Varma, Sameer

    2013-02-12

    The ensemble of three-dimensional (3-D) configurations exhibited by a molecule, that is, its intrinsic motion, can be altered by several environmental factors, and also by the binding of other molecules. Quantification of such induced changes in intrinsic motion is important because it provides a basis for relating thermodynamic changes to changes in molecular motion. This task is, however, challenging because it requires comparing two high-dimensional data sets. Traditionally, when analyzing molecular simulations, this problem is circumvented by first reducing the dimensions of the two ensembles separately, and then comparing summary statistics from the two ensembles against each other. However, since dimensionality reduction is carried out prior to ensemble comparison, such strategies are susceptible to artifactual biases from information loss. Here, we introduce a method based on support vector machines that yields a normalized quantitative estimate for the difference between two ensembles after comparing them directly against one another. While this method can be applied to any molecular system, including nonbiological molecules and crystals, here, we show how it can be applied to identify the specific regions of a paramyxovirus G protein that are affected by the binding of its preferred human receptor, Ephrin B2. This protein-protein interaction initiates the fusion of the virus with the host cell. Specifically, for every residue in the G protein, we obtain separately a quantitative difference between the ensemble of configurations they sample in the presence and in the absence of Ephrin B2. These ensembles were generated using molecular dynamics simulations. Rank-ordering and then mapping the residues that undergo the greatest change in motion onto the 3-D structure of the G protein reveals that they are clustered primarily on a single contiguous facet of the protein and include the set that is known experimentally to play a vital role in regulating viral

  15. 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.

  16. Southern Ocean isopycnal mixing and ventilation changes driven by winds

    NASA Astrophysics Data System (ADS)

    Abernathey, Ryan; Ferreira, David

    2015-12-01

    Observed and predicted changes in the strength of the westerly winds blowing over the Southern Ocean have motivated a number of studies on the response of the Antarctic Circumpolar Current and Southern Ocean meridional overturning circulation (MOC) to wind perturbations and led to the hypothesis of the "eddy compensation" regime, wherein the MOC becomes insensitive to wind changes. In addition to the MOC, tracer transport also depends on mixing processes. Here we show, in a high-resolution process model, that isopycnal mixing by mesoscale eddies is strongly dependent on the wind strength. This dependence can be explained by mixing length theory and is driven by increases in eddy kinetic energy; the mixing length does not change strongly in our simulation. Simulation of a passive ventilation tracer (analogous to CFCs or anthropogenic CO2) demonstrates that variations in tracer uptake across experiments are dominated by changes in isopycnal mixing, rather than changes in the MOC. We argue that to properly understand tracer uptake under different wind-forcing scenarios, the sensitivity of isopycnal mixing to winds must be accounted for.

  17. A modified approach for change detection using change vector analysis in posterior probability space

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    The multispectral and multitemporal data coming from satellites allow us to extract valuable spatiotemporal change. Consequently, Earth surface change detection analysis has been used in the past to monitor land cover changes caused by different reasons. Several techniques have been used for that purpose and change vector analysis (CVA) has been frequently employed to carry out automatic spatiotemporal information extraction. This work describes a modified methodology based on Supervised Change Vector Analysis in Posterior probability Space (SCVAPS) with the final aim of obtaining a change detection map in Blida, Algeria. The proposed technique is a Modified version of Supervised Change Vector Analysis Posterior probability Space (MSCVAPS) and it is applied at the same region that the original technique studied in the literature. The classical Maximum Likelihood classifier is the selected method for supervised classification since it provides good properties in the posterior probability map. An improved method for threshold determination based on Double Flexible Pace Search (DFPS) is proposed in this work and it is employed to obtain the most adequate threshold value. Then, the MSCVAPS approach is evaluated by two cases study of the land cover change detection in the region of Blida, Algeria, and in the region of Shunyi District, Beijing, China, using a pair of Landsat Thematic Mapper images and pair of Landsat Enhanced Thematic Mapper images, respectively. The final evaluation is given by the overall accuracy of changed and unchanged pixels and the kappa coefficient. The results show that the modified approach gives excellent results using the same area of study that was selected in the literature.

  18. 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. PMID:24874183

  19. 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

    2014-07-01

    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. PMID:24994651

  20. Measuring the turbulent wind vector with a weight-shift Microlight Aircraft

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Neidl, F.; Butterbach-Bahl, K.; Schmid, H. P.; Beyrich, F.; Zheng, X. H.; Foken, T.

    2009-09-01

    The Small Environmental Research Aircraft (SERA) D-MIFUs initial fields of application are aerosol / cloud and radiation transfer research. Therefore a comparatively slow (True Airspeed, TAS ~25 ms-1) but highly mobile microlight aircraft was envisaged. To broaden the application area of D-MIFU we explore whether the microlight can also be used for Eddy Covariance (EC) flux measurement. To obtain useful data sets for airborne EC a reliable turbulent Wind Vector (WV) measurement is a key requirement. Here we present methodology and results to calibrate and express performance and uncertainty of microlight based WV measurement. Specific attention is given to the influence of the flexible-wing weight-shift geometry on the WV measurement. For the WV measurement we equipped D-MIFU with a 70 cm long noseboom supporting a classical 5 hole probe and a fast 50 μm diameter thermocouple. An Inertial Navigation System (INS) supplies high accuracy ground speeds (Ï?=0.05 ms-1) and attitude angles (Ï?=0.03° , 0.1° respectively for heading). Data are stored with 10 Hz yielding a horizontal resolution of 2.5 m. The INS also allows to analyze aircraft dynamics such as 3d rotation rates and acceleration of the nacelle body. Further estimates for 3d acceleration of airfoil and noseboom are obtained at 100 Hz. The noseboom calibration coefficients under laboratory conditions were obtained by wind tunnel- and thermal bath measurements. To transfer these characteristics for in-flight conditions we carried out a series of flights with D-MIFU above the Boundary Layer under calm conditions. On basis of level flights at different power settings we were able to determine dynamic pressure-, sideslip- and attack angle offsets. Additionally forced maneuvers, such as e.g. phugoids, have been performed. By means of multivariate analysis these data are used to assess and minimize the impact of microlight nacelle and airfoil rapidly varying motions (RVM) on the WV components. In the final

  1. 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…

  2. Evaluation of turbulent magnetic energy spectra in the three-dimensional wave vector domain in the solar wind

    SciTech Connect

    Gary, S Peter; Narita, Y; Glassmeier, K H; Goldstein, M L; Safraoui, F; Treumann, R A

    2009-01-01

    Using four-point measurements of the CLUSTER spacecraft, the energy distribution of magnetic field fluctuations in the solar wind is determined directly in the three-dimensional wave vector domain in the range 3 x 10{sup -4} rad/km < k < 3 x 10{sup -3} rad/km. The analysis method takes account of a regular tetrahedron configuration of CLUSTER and the Doppler effect. The energy distribution in the flow rest frame is anisotropic, characterized by two distinct extended structures perpendicular to the mean magnetic field and furthermore perpendicular to the flow direction. The three-dimensional distribution is averaged around the direction of the mean magnetic field direction, and then is further reduced to one-dimensional distributions in the wave number domain parallel and perpendicular to the mean magnetic field. The one-dimensional energy spectra are characterized by the power law with the index -5/3 and furthermore very close energy density between parallel and perpendicular directions to the mean magnetic field at the same wave numbers. Though the distributions and the spectra are not covered in a wide range of wave vectors, our measurements suggest that the solar wind fluctuation is anisotropic in the three-dimensional wave vector space. It is, however, rather isotropic when reduced into the parallel and perpendicular wave vector geometries due to the second anisotropy imposed by the flow direction.

  3. Water Vapor Winds and Their Application to Climate Change Studies

    NASA Technical Reports Server (NTRS)

    Jedlovec, Gary J.; Lerner, Jeffrey A.

    2000-01-01

    The retrieval of satellite-derived winds and moisture from geostationary water vapor imagery has matured to the point where it may be applied to better understanding longer term climate changes that were previously not possible using conventional measurements or model analysis in data-sparse regions. In this paper, upper-tropospheric circulation features and moisture transport covering ENSO periods are presented and discussed. Precursors and other detectable interannual climate change signals are analyzed and compared to model diagnosed features. Estimates of winds and humidity over data-rich regions are used to show the robustness of the data and its value over regions that have previously eluded measurement.

  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. 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

  6. 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

  7. Potential contribution of wind energy to climate change mitigation

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    It is still possible to limit greenhouse gas emissions to avoid the 2 °C warming threshold for dangerous climate change. Here we explore the potential role of expanded wind energy deployment in climate change mitigation efforts. At present, most turbines are located in extra-tropical Asia, Europe and North America, where climate projections indicate continuity of the abundant wind resource during this century. Scenarios from international agencies indicate that this virtually carbon-free source could supply 10-31% of electricity worldwide by 2050 (refs , ). Using these projections within Intergovernmental Panel on Climate Change Representative Concentration Pathway (RCP) climate forcing scenarios, we show that dependent on the precise RCP followed, pursuing a moderate wind energy deployment plan by 2050 delays crossing the 2 °C warming threshold by 1-6 years. Using more aggressive wind turbine deployment strategies delays 2 °C warming by 3-10 years, or in the case of RCP4.5 avoids passing this threshold altogether. To maximize these climate benefits, deployment of non-fossil electricity generation must be coupled with reduced energy use.

  8. 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.

  9. Long-Term Changes in the Equatorial Pacific Trade Winds.

    NASA Astrophysics Data System (ADS)

    Clarke, Allan J.; Lebedev, Anna

    1996-05-01

    Past work has shown that surface zonal equatorial wind stress, zonally integrated from one side of the Pacific to the other, is the key variable for estimating long-term El Niño behavior in the eastern Pacific. The long-term behavior of this key variable is difficult to determine directly because of the paucity of the equatorial wind observations and because of false trends in the wind data introduced by gradual changes in the methods of wind measurement. However, surface pressure data generally does not suffer from these false trends and theory suggests that this key wind variable is linearly related to the difference (p) of surface atmospheric pressure between the eastern and western equatorial Pacific. Detrended COADS pressure in the eastern and western equatorial Pacific and post 1960 detrended equatorial wind stress zonally averaged across the Pacific were used to verify this relationship. Pressure difference and zonally averaged equatorial zonal windstress () were highly correlated (r = 0.90) and the regression also showed that advection of zonal momentum contributes substantially to the momentum balance in the equatorial atmospheric boundary layer. Further, hindcasts of eastern equatorial Pacific sea surface temperature and sea level indicated that from p was more accurate than from winds even since 1960 when wind data were more plentiful. This suggests that the simple pressure difference p is an effective way to monitor both in the past and in the future.Using the p time series as a proxy for zonally integrated wind stress suggests that the equatorial trades strengthened during the early and mid-1930s, weakened from the late 1930s to late 1950s, strengthened during the 1960s, and weakened rapidly since. This pattern is qualitatively consistent with the long record of sea surface temperature measurements at Puerto Chicama (Peru). The more recent rapid weakening is consistent with trends in several physical variables reported previously by others. The long

  10. 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

  11. Analysis of wind bias change with respect to time at Cape Kennedy, Florida, and Vandenberg AFB, California

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1978-01-01

    A statistical analysis is presented of the temporal variability of wind vectors at 1 km altitude intervals from 0 to 27 km altitude after applying a digital filter to the original wind profile data sample.

  12. 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.

  13. Effect of climate change on vector-borne disease risk in the UK.

    PubMed

    Medlock, Jolyon M; Leach, Steve A

    2015-06-01

    During the early part of the 21st century, an unprecedented change in the status of vector-borne disease in Europe has occurred. Invasive mosquitoes have become widely established across Europe, with subsequent transmission and outbreaks of dengue and chikungunya virus. Malaria has re-emerged in Greece, and West Nile virus has emerged throughout parts of eastern Europe. Tick-borne diseases, such as Lyme disease, continue to increase, or, in the case of tick-borne encephalitis and Crimean-Congo haemorrhagic fever viruses, have changed their geographical distribution. From a veterinary perspective, the emergence of Bluetongue and Schmallenberg viruses show that northern Europe is equally susceptible to transmission of vector-borne disease. These changes are in part due to increased globalisation, with intercontinental air travel and global shipping transport creating new opportunities for invasive vectors and pathogens. However, changes in vector distributions are being driven by climatic changes and changes in land use, infrastructure, and the environment. In this Review, we summarise the risks posed by vector-borne diseases in the present and the future from a UK perspective, and assess the likely effects of climate change and, where appropriate, climate-change adaptation strategies on vector-borne disease risk in the UK. Lessons from the outbreaks of West Nile virus in North America and chikungunya in the Caribbean emphasise the need to assess future vector-borne disease risks and prepare contingencies for future outbreaks. Ensuring that adaptation strategies for climate change do not inadvertently exacerbate risks should be a primary focus for decision makers. PMID:25808458

  14. 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

  15. 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

    2016-01-01

    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

  16. 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.

  17. Modeling vector-borne disease risk in migratory animals under climate change.

    PubMed

    Hall, Richard J; Brown, Leone M; Altizer, Sonia

    2016-08-01

    Recent theory suggests that animals that migrate to breed at higher latitudes may benefit from reduced pressure from natural enemies, including pathogens ("migratory escape"), and that migration itself weeds out infected individuals and lowers infection prevalence ("migratory culling"). The distribution and activity period of arthropod disease vectors in temperate regions is expected to respond rapidly to climate change, which could reduce the potential for migratory escape. However, climate change could have the opposite effect of reducing transmission if differential responses in the phenology and distribution of migrants and disease vectors reduce their overlap in space and time. Here we outline a simple modeling framework for exploring the influence of climate change on vector-borne disease dynamics in a migratory host. We investigate two scenarios under which pathogen transmission dynamics might be mediated by climate change: (1) vectors respond more rapidly than migrants to advancing phenology at temperate breeding sites, causing peak susceptible host density and vector emergence to diverge ("migratory mismatch") and (2) reduced migratory propensity allows increased nonbreeding survival of infected hosts and larger breeding-site epidemics (loss of migratory culling, here referred to as "sedentary amplification"). Our results highlight the need for continued surveillance of climate-induced changes to migratory behavior and vector activity to predict pathogen prevalence and its impacts on migratory animals. PMID:27252225

  18. 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.

  19. Confidence and sensitivity study of the OAFlux multisensor synthesis of the global ocean surface vector wind from 1987 onward

    NASA Astrophysics Data System (ADS)

    Yu, Lisan; Jin, Xiangze

    2014-10-01

    This study presented an uncertainty assessment of the high-resolution global analysis of daily-mean ocean-surface vector winds (1987 onward) by the Objectively Analyzed air-sea Fluxes (OAFlux) project. The time series was synthesized from multiple satellite sensors using a variational approach to find a best fit to input data in a weighted least-squares cost function. The variational framework requires the a priori specification of the weights, or equivalently, the error covariances of input data, which are seldom known. Two key issues were investigated. The first issue examined the specification of the weights for the OAFlux synthesis. This was achieved by designing a set of weight-varying experiments and applying the criteria requiring that the chosen weights should make the best-fit of the cost function be optimal with regard to both input satellite observations and the independent wind time series measurements at 126 buoy locations. The weights thus determined represent an approximation to the error covariances, which inevitably contain a degree of uncertainty. Hence, the second issue addressed the sensitivity of the OAFlux synthesis to the uncertainty in the weight assignments. Weight perturbation experiments were conducted and ensemble statistics were used to estimate the sensitivity. The study showed that the leading sources of uncertainty for the weight selection are high winds (>15 ms-1) and heavy rain, which are the conditions that cause divergence in wind retrievals from different sensors. Future technical advancement made in wind retrieval algorithms would be key to further improvement of the multisensory synthesis in events of severe storms.

  20. 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.

  1. Determination of the Wind-Velocity Vector Above the Ocean Surface Using the Image Spectrum of a Polarimetric Radar with Synthesized Aperture

    NASA Astrophysics Data System (ADS)

    Panfilova, M. A.; Kanevsky, M. B.; Balandina, G. N.; Karaev, V. Yu.; Stoffelen, A.; Verkhoev, A.

    2015-09-01

    We propose a new method for determining the wind-velocity vector above the ocean surface using the data of a polarimetric synthetic aperture radar. The preliminary calculations show that for wind waves, the location of the maximum in the radar image is unambiguously related to the wind velocity, whereas the wind direction is retrieved with an uncertainty of 180°, which is related to the central symmetry of the image spectrum. To eliminate the ambiguity when determining the wind direction, a criterion based on the information on the sign of the coefficient of correlation among the complex signals on the co- and cross polarizations is used. It is shown that using the polarimetric radar, it is theoretically possible to obtain information on both the wind velocity and direction without exact radar calibration.

  2. Ground-based remote sensing of wind vector and visibility: latest results from guideline development

    NASA Astrophysics Data System (ADS)

    Boesenberg, Jens; Danzeisen, Hans H.; Engelbart, Dirk; Fritzsche, Klaus; Klein, Volker; Muenkel, Christoph; Trickl, Thomas; Werner, Christian; Woppowa, Ljuba

    1999-09-01

    Methods which are in discussion to enter a VDI guideline will be presented. Examples of application in local scale area selected. The VDI 'Richtlinie VDI 3786 Umweltmeteorologie,' is divided in many parts. Part 15 shows the remote sensing methods for visibility measurements, part 14 describes the wind profile measurements. Wind profiles in the atmospheric boundary layer yield a very important contribution also to the investigation of atmospheric exchange processes. The wind field in the atmospheric boundary layer is highly variable in spatial and temporal scales. For a few applications a more frequent wind sensing is necessary, i.e. (1) on airports located in low level jet areas, (2) near chemical plants to get information of the transport of toxic gases from leakages,(3) for meteorology in general to improve the weather forecast, (4) for environment protection purposes like dispersion studies. The following statements are valid for visibility measurements: (1) Lidar can provide the same information of the visibility as conventional sensors, but in addition lidar will provide range resolved measurements. (2) It is possible to shrink a lidar down to the size of binoculars. (3) It is possible to measure local visibility with an eye-safe (class 1) lidar. (4) Layers can be detected up to 250 m distance in approximately 2 s even with a small size instrument.

  3. Characteristics of Wind Velocity and Temperature Change Near an Escarpment-Shaped Road Embankment

    PubMed Central

    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. PMID:25136681

  4. 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. PMID:25136681

  5. Vector-borne parasitic diseases--an overview of recent changes.

    PubMed

    Molyneux, D H

    1998-06-01

    This paper summarises the impact of different changes (environmental, ecological, developmental) on the one hand, with the impact of control measures on the other. The former group of changes have tended to exacerbate the incidence and prevalence of vector-borne parasitic diseases while the reduced public funds available for the health sector have reduced disease surveillance systems. However, some vector control/eradication programmes have been successful. Vector control in onchocerciasis and Chagas' disease and immediate host control in Guinea worm have reduced the public health importance of these disease. This contrasts, with malaria, where the complexity of different ecological situations and the variable vector ecology have made control difficult and epidemics frequent and unpredictable. Advances in our knowledge of how to implement and sustain insecticide-impregnated bednets which reduce morbidity and mortality in under 5-year olds will be a key issue for the coming years. In African trypanosomiasis and leishmaniasis, where control is dependent on effective diagnosis and surveillance followed by high-cost drug treatment, the health services are faced with major challenges--lack of drug availability and diagnostics no vector control--the diseases in some areas assuming epidemic status yet health services are unable to respond. Human African trypanosomiasis and visceral leishmaniasis are fatal if untreated, and require an emergency response approach. Changing vector distribution of Glossina is related to the ability of riverine flies of Glossina palpalis group to adapt to new vegetation patterns. In leishmaniasis changes have occurred in the distribution of the disease associated with development impact, urbanisation, civil unrest and changed agroforestry practice. PMID:9673871

  6. Predicting the effect of climate change on African trypanosomiasis: integrating epidemiology with parasite and vector biology

    PubMed Central

    Moore, Sean; Shrestha, Sourya; Tomlinson, Kyle W.; Vuong, Holly

    2012-01-01

    Climate warming over the next century is expected to have a large impact on the interactions between pathogens and their animal and human hosts. Vector-borne diseases are particularly sensitive to warming because temperature changes can alter vector development rates, shift their geographical distribution and alter transmission dynamics. For this reason, African trypanosomiasis (sleeping sickness), a vector-borne disease of humans and animals, was recently identified as one of the 12 infectious diseases likely to spread owing to climate change. We combine a variety of direct effects of temperature on vector ecology, vector biology and vector–parasite interactions via a disease transmission model and extrapolate the potential compounding effects of projected warming on the epidemiology of African trypanosomiasis. The model predicts that epidemics can occur when mean temperatures are between 20.7°C and 26.1°C. Our model does not predict a large-range expansion, but rather a large shift of up to 60 per cent in the geographical extent of the range. The model also predicts that 46–77 million additional people may be at risk of exposure by 2090. Future research could expand our analysis to include other environmental factors that influence tsetse populations and disease transmission such as humidity, as well as changes to human, livestock and wildlife distributions. The modelling approach presented here provides a framework for using the climate-sensitive aspects of vector and pathogen biology to predict changes in disease prevalence and risk owing to climate change. PMID:22072451

  7. A Delay Vector Variance based Marker for an Output-Only Assessment of Structural Changes in Tension Leg Platforms

    NASA Astrophysics Data System (ADS)

    Jaksic, V.; Wright, C.; Mandic, D. P.; Murphy, J.; Pakrashi, V.

    2015-07-01

    Although aspects of power generation of many offshore renewable devices are well understood, their dynamic responses under high wind and wave conditions are still to be investigated to a great detail. Output only statistical markers are important for these offshore devices, since access to the device is limited and information about the exposure conditions and the true behaviour of the devices are generally partial, limited, and vague or even absent. The markers can summarise and characterise the behaviour of these devices from their dynamic response available as time series data. The behaviour may be linear or nonlinear and consequently a marker that can track the changes in structural situations can be quite important. These markers can then be helpful in assessing the current condition of the structure and can indicate possible intervention, monitoring or assessment. This paper considers a Delay Vector Variance based marker for changes in a tension leg platform tested in an ocean wave basin for structural changes brought about by single column dampers. The approach is based on dynamic outputs of the device alone and is based on the estimation of the nonlinearity of the output signal. The advantages of the selected marker and its response with changing structural properties are discussed. The marker is observed to be important for monitoring the as- deployed structural condition and is sensitive to changes in such conditions. Influence of exposure conditions of wave loading is also discussed in this study based only on experimental data.

  8. 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.

  9. 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.

  10. 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.

  11. Flare-related changes in pseudo-vector magnetic field derived from line-of-sight magnetograms

    NASA Astrophysics Data System (ADS)

    Burtseva, Olga; Gosain, Sanjay; Pevtsov, Alexei A.

    2016-05-01

    Longitudinal field is a projection of full vector field to the line-of-sight direction. Thus, it is possible to derive some information about the vector field from line-of-sight data in round sunspots, assuming that average properties of vector magnetic field in these sunspots depend mostly on distance from center of sunspot. Under this assumption, one can reconstruct vertical, radial, and tangential components of vector magnetic field using azimuthal averaging. This technique can be useful for investigation of twist and inclination in magnetic field in particular in flaring regions when vector data are not available. In this study we validate the cylindrical symmetry technique on example of a simple round sunspot. Then we attempt to study changes in (pseudo-vector) magnetic fields in isolated and round sunspots associated with flare events using SDO/HMI longitudinal magnetograms. We compare the pseudo-vector results with vector data.

  12. 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. PMID:25412801

  13. 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

    2015-04-01

    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

  14. Climate change and threat of vector-borne diseases in India: are we prepared?

    PubMed

    Dhiman, Ramesh C; Pahwa, Sharmila; Dhillon, G P S; Dash, Aditya P

    2010-03-01

    It is unequivocal that climate change is happening and is likely to expand the geographical distribution of several vector-borne diseases, including malaria and dengue etc. to higher altitudes and latitudes. India is endemic for six major vector-borne diseases (VBD) namely malaria, dengue, chikungunya, filariasis, Japanese encephalitis and visceral leishmaniasis. Over the years, there has been reduction in the incidence of almost all the diseases except chikungunya which has re-emerged since 2005. The upcoming issue of climate change has surfaced as a new threat and challenge for ongoing efforts to contain vector-borne diseases. There is greater awareness about the potential impacts of climate change on VBDs in India and research institutions and national authorities have initiated actions to assess the impacts. Studies undertaken in India on malaria in the context of climate change impact reveal that transmission windows in Punjab, Haryana, Jammu and Kashmir and north-eastern states are likely to extend temporally by 2-3 months and in Orissa, Andhra Pradesh and Tamil Nadu there may be reduction in transmission windows. Using PRECIS model (driven by HadRM2) at the resolution of 50 x 50 Km for daily temperature and relative humidity for year 2050, it was found that Orissa, West Bengal and southern parts of Assam will still remain malarious and transmission windows will open up in Himachal Pradesh and north-eastern states etc. Impact of climate change on dengue also reveals increase in transmission with 2 C rise in temperature in northern India. Re-emergence of kala-azar in northern parts of India and reappearance of chikungunya mainly in southern states of India has also been discussed. The possible need to address the threat and efforts made in India have also been highlighted. The paper concludes with a positive lead that with better preparedness threat of climate change on vector-borne diseases may be negated. PMID:20155369

  15. 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. PMID:27322480

  16. 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

  17. 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

  18. 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. PMID:24019459

  19. Things Fall Apart: Topology Change From Winding Tachyons

    SciTech Connect

    Adams, A.

    2005-02-04

    We argue that closed string tachyons drive two spacetime topology changing transitions--loss of genus in a Riemann surface and separation of a Riemann surface into two components. The tachyons of interest are localized versions of Scherk-Schwarz winding string tachyons arising on Riemann surfaces in regions of moduli space where string-scale tubes develop. Spacetime and world-sheet renormalization group analyses provide strong evidence that the decay of these tachyons removes a portion of the spacetime, splitting the tube into two pieces. We address the fate of the gauge fields and charges lost in the process, generalize it to situations with weak flux backgrounds, and use this process to study the type 0 tachyon, providing further evidence that its decay drives the theory sub-critical. Finally, we discuss the time-dependent dynamics of this topology-changing transition and find that it can occur more efficiently than analogous transitions on extended supersymmetric moduli spaces, which are limited by moduli trapping.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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…

  5. 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

  6. 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. PMID:26419410

  7. Magnetosheath for almost-aligned solar wind magnetic field and flow vectors: Windobservations across the dawnside magnetosheath at X = -12 Re

    NASA Astrophysics Data System (ADS)

    Farrugia, Charles

    While there are many approximations describing the flow of the solar wind past the mag-netosphere in the magnetosheath, the case of perfectly aligned (parallel or anti-parallel) in-terplanetary magnetic field (IMF) and solar wind flow vectors can be treated exactly in an magnetohydrodynamic (MHD) approach (Spreiter and Rizzi, 1974). In this work we examine a case of nearly-opposed (to within 15 deg) interplanetary field and flow vectors, which occurred on October 24-25, 2001 during passage of the last interplanetary coronal mass ejection in an ejecta merger. Interplanetary data are from the ACE spacecraft. Simultaneously Wind was crossing the near-Earth (X -13 Re) geomagnetic tail and subsequently made a 5-hour-long magnetosheath crossing close to the ecliptic plane (Z = -0.7 Re). Geomagnetic activity was returning steadily to quiet, "ground" conditions. We first compare the predictions of the Spre-iter and Rizzi theory with the Wind magnetosheath observations and find fair agreement, in particular as regards the proportionality of the magnetic field strength and the product of the plasma density and bulk speed. We then carry out a small-perturbation analysis of the Spreiter and Rizzi solution to account for the small IMF components perpendicular to the flow vector. The resulting expression is compared to the time series of the observations and satisfactory agreement is obtained. We also present and discuss observations in the dawnside boundary layer of pulsed, high-speed (v 600 km/s) flows exceeding the solar wind flow speeds. We examine various generating mechanisms and suggest that the most likely causeis a wave of frequency 3.2 mHz excited at the inner edge of the boundary layer.

  8. Quantifying changes in the bone microarchitecture using Minkowski-functionals and scaling vectors: a comparative study

    NASA Astrophysics Data System (ADS)

    Raeth, Christoph W.; Mueller, Dirk; Link, Thomas M.; Boehm, Holger; Monetti, Roberto

    2006-03-01

    Osteoporosis is a metabolic bone disease leading to de-mineralization and increased risk of fracture. The two major factors that determine the biomechanical competence of bone are the degree of mineralization and the micro-architectural integrity. Today, modern imaging modalities exist that allow to depict structural details of trabecular bone tissue. Recently, non-linear techniques in 2D and 3D based on the scaling vector method (SVM) and the Minkowski functionals (MF) have been introduced, which show excellent performance in predicting bone strength and fracture risk. However, little is known about the performance of the various parameters with respect to monitoring structural changes due to progression of osteoporosis or as a result of medical treatment. We test and compare the two methodologies using realistic two-dimensional simulations of bone structures, which model the effect of osteoblasts and osteoclasts on the local change of relative bone density. Different realizations with slightly varying control parameters are considered. Our results show that even small changes in the trabecular structures, which are induced by variation of a control parameter of the system, become discernible by applying both the MF and the locally adapted scaling vector method. The results obtained with SVM are superior to those obtained with the Minkowski functionals. An additive combination of both measures drastically increases the sensitivity to slight changes in bone structures. These findings may be especially important for monitoring the treatment of patients, where the early recognition of (drug-induced) changes in the trabecular structure is crucial.

  9. OBSERVATIONAL EVIDENCE OF CHANGING PHOTOSPHERIC VECTOR MAGNETIC FIELDS ASSOCIATED WITH SOLAR FLARES

    SciTech Connect

    Su, J. T.; Jing, J.; Wang, H. M.; Mao, X. J.; Wang, X. F.; Zhang, H. Q.; Deng, Y. Y.; Guo, J.; Wang, G. P.

    2011-06-01

    Recent observations have provided evidence that the solar photospheric magnetic fields could have rapid and permanent changes in both longitudinal and transverse components associated with major flares. As a result, the Lorentz force (LF) acting on the solar photosphere and solar interior could be perturbed, and the change of LF is always nearly in the downward direction. However, these rapid and permanent changes have not been systematically investigated, yet, using vector magnetograms. In this paper, we analyze photospheric vector magnetograms covering five flares to study the evolution of photospheric magnetic fields. In particular, we investigate two-dimensional spatial distributions of the changing LF. Around the major flaring polarity inversion line, the net change of the LF is directed downward in an area of {approx}10{sup 19} cm{sup 2} for X-class flares. For all events, the white-light observations show that sunspots darken in this location after flares, and magnetic fields become more inclined, which is consistent with the ideas put forward by Hudson et al. and Fisher et al., and observations.

  10. 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.

  11. 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.

  12. 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.

  13. 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)

  14. 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

  15. 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

  16. Mosquitoes and Culicoides biting midges: vector range and the influence of climate change.

    PubMed

    Elbers, A R W; Koenraadt, C J M; Meiswinkel, R

    2015-04-01

    Vector-borne animal diseases pose a continuous and substantial threat to livestock economies around the globe. Increasing international travel, the globalisation of trade, and climate change are likely to play a progressively more important role in the introduction, establishment and spread of arthropod-borne pathogens worldwide. A review of the literature reveals that many climatic variables, functioning singly or in combination, exert varying effects on the distribution and range of Culicoides vector midges and mosquitoes. For example, higher temperatures may be associated with increased insect abundance--thereby amplifying the risk of disease transmission--but there are no indications yet of dramatic shifts occurring in the geographic range of Culicoides midges. However, the same cannot be said for mosquitoes: over the last few decades, multiple Asian species have established themselves in Europe, spread and are unlikely to ever be eradicated. Research on how insects respond to changes in climate is still in its infancy. The authors argue that we need to grasp how other annectant changes, such as extremes in precipitation (drought and flooding), may affect the dispersal capability of mosquitoes. Models are useful for assessing the interplay between mosquito vectors expanding their range and the native flora and fauna; however, ecological studies employing classical mark-release-recapture techniques remain essential for addressing fundamental questions about the survival and dispersal of mosquito species, with the resulting parameters fed directly into new-generation disease transmission models. Studies on the eventual impact of mosquitoes on animal and human health should be tackled through large-scale integrated research programmes. Such an approach calls for more collaborative efforts, along the lines of the One Health Initiative. PMID:26470453

  17. Potential Influence of Climate Change on Vector-Borne and Zoonotic Diseases: A Review and Proposed Research Plan

    PubMed Central

    Mills, James N.; Gage, Kenneth L.; Khan, Ali S.

    2010-01-01

    Background Because of complex interactions of climate variables at the levels of the pathogen, vector, and host, the potential influence of climate change on vector-borne and zoonotic diseases (VBZDs) is poorly understood and difficult to predict. Climate effects on the nonvector-borne zoonotic diseases are especially obscure and have received scant treatment. Objective We described known and potential effects of climate change on VBZDs and proposed specific studies to increase our understanding of these effects. The nonvector-borne zoonotic diseases have received scant treatment and are emphasized in this paper. Data sources and synthesis We used a review of the existing literature and extrapolations from observations of short-term climate variation to suggest potential impacts of climate change on VBZDs. Using public health priorities on climate change, published by the Centers for Disease Control and Prevention, we developed six specific goals for increasing understanding of the interaction between climate and VBZDs and for improving capacity for predicting climate change effects on incidence and distribution of VBZDs. Conclusions Climate change may affect the incidence of VBZDs through its effect on four principal characteristics of host and vector populations that relate to pathogen transmission to humans: geographic distribution, population density, prevalence of infection by zoonotic pathogens, and the pathogen load in individual hosts and vectors. These mechanisms may interact with each other and with other factors such as anthropogenic disturbance to produce varying effects on pathogen transmission within host and vector populations and to humans. Because climate change effects on most VBZDs act through wildlife hosts and vectors, understanding these effects will require multidisciplinary teams to conduct and interpret ecosystem-based studies of VBZD pathogens in host and vector populations and to identify the hosts, vectors, and pathogens with the

  18. 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.

  19. 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. PMID:25215326

  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. 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

  2. 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. PMID:27278360

  3. 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

  4. Climate, Environmental, and Socioeconomic Change Weighing up the Balance in Vector-Borne Disease Transmission

    DOE PAGESBeta

    Parham, Paul; Waldock, Johanna; Christophides, George; Hemming, Deborah; Agusto, Folashade; Evans, Katherine J; Fefferman, Nina; Gaff, Holly; Gumel, Abba; LaDeau, Shannon; et al

    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 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

  5. Climate, Environmental, and Socioeconomic Change Weighing up the Balance in Vector-Borne Disease Transmission

    SciTech Connect

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

    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 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.

  6. Evaluation of High-Resolution Ocean Surface Vector Winds Measured by QuikSCAT Scatterometer in Coastal Regions

    NASA Technical Reports Server (NTRS)

    Tang, Wenqing; Liu, W. Timothy; Stiles, Bryan W.

    2004-01-01

    The SeaWinds scatterometer onboard QuikSCAT covers approximately 90% of the global ocean under clear and cloudy condition in 24 h, and the standard data product has 25-km spatial resolution. Such spatial resolution is not sufficient to resolve small-scale processes, especially in coastal oceans. Based on range-compressed normalized backscatter and a modified wind retrieval algorithm, a coastal wind dataset at 12.5-km resolution was produced. Even with larger error, the high-resolution winds, in medium to high strength, would still be useful over coastal ocean. Using measurements from moored buoys from the National Buoy Data Center, the high-resolution QuikSCAT wind data are found to have similar accuracy as standard data in the open ocean. The accuracy of both high- and standard-resolution winds, particularly in wind directions, is found to degrade near shore. The increase in error is likely caused by the inadequacy of the geophysical model function/ambiguity removal scheme in addressing coastal conditions and light winds situations. The modified algorithm helps to bring the directional accuracy of the high-resolution winds to the accuracy of the standard-resolution winds in near-shore regions, particularly in the nadir and far zones across the satellite track.

  7. 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

  8. 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.

  9. 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'. PMID:27550759

  10. Evaluation of wind vectors observed by HY-2A scatterometer using ocean buoy observations, ASCAT measurements, and numerical model data

    NASA Astrophysics Data System (ADS)

    Li, Dawei; Shen, Hui

    2015-09-01

    The first Chinese microwave ocean environment satellite HY-2A was launched successfully in August, 2011. This study presents a quality assessment of HY-2A scatterometer (HYSCAT) data based on comparison with ocean buoy data, the Advanced Scatterometer (ASCAT) data, and numerical model data from the National Centers for Environmental Prediction (NCEP). The in-situ observations include those from buoy arrays operated by the National Data Buoy Center (NDBC) and Tropical Atmosphere Ocean (TAO) project. Only buoys located offshore and in deep water were analyzed. The temporal and spatial collocation windows between HYSCAT data and buoy observations were 30 min and 25 km, respectively. The comparisons showed that the wind speeds and directions observed by HYSCAT agree well with the buoy data. The root-mean-squared errors (RMSEs) of wind speed and direction for the HYSCAT standard wind products are 1.90 m/s and 22.80°, respectively. For the HYSCAT-ASCAT comparison, the temporal and spatial differences were limited to 1 h and 25 km, respectively. This comparison yielded RMSEs of 1.68 m/s for wind speed and 19.1° for wind direction. We also compared HYSCAT winds with reanalysis data from NCEP. The results show that the RMSEs of wind speed and direction are 2.6 m/s and 26°, respectively. The global distribution of wind speed residuals (HYSCAT-NCEP) is also presented here for evaluation of the HYSCAT-retrieved wind field globally. Considering the large temporal and spatial differences of the collocated data, it is concluded that the HYSCAT-retrieved wind speed and direction met the mission requirements, which were 2 m/s and 20° for wind speeds in the range 2-24 m/s. These encouraging assessment results show that the wind data obtained from HYSCAT will be useful for the scientific community.

  11. Future changes to the Indonesian Throughflow and Pacific circulation: The differing role of wind and deep circulation changes

    NASA Astrophysics Data System (ADS)

    Sen Gupta, Alex; McGregor, Shayne; Sebille, Erik; Ganachaud, Alexandre; Brown, Jaclyn N.; Santoso, Agus

    2016-02-01

    Climate models consistently project a substantial decrease in the Indonesian Throughflow (ITF) in response to enhanced greenhouse warming. On interannual timescales ITF changes are largely related to tropical Pacific wind variability. However, on the multidecadal timescales investigated here we demonstrate that regional winds and associated changes in the upper ocean circulation cannot explain the projected ITF decrease. Instead, the decrease is related to a weakening in the northward flow of deep waters entering the Pacific basin at ~40°S and an associated reduction in the net basin-wide upwelling to the north of the southern tip of Australia. This can be traced back to consistent changes in the Antarctic Circumpolar Current and Southern Ocean overturning, although questions still remain as to the ultimate drivers. In contrast to the ITF decrease, substantial projected changes to the upper ocean circulation of the Pacific basin are well explained by robust changes in the surface winds.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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 morning sector and a decrease in the aftenoon 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 from the north pole everywhere at subauroral latitudes except the dayside morning sector.

  13. 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.

  14. Age-related changes in the control of finger force vectors.

    PubMed

    Kapur, Shweta; Zatsiorsky, Vladimir M; Latash, Mark L

    2010-12-01

    We explored changes in finger interaction in the process of healthy aging as a window into neural control strategies of natural movements. In particular, we quantified the amount of force produced by noninstructed fingers in different directions, the amount of force produced by the instructed finger orthogonally to the task direction, and the strength of multifinger synergies stabilizing the total force magnitude and direction during accurate force production. Healthy elderly participants performed accurate isometric force production tasks in five directions by individual fingers and by all four fingers acting together. Their data were compared with a dataset obtained in a similar earlier study of young subjects. Finger force vectors were measured using six-component force/torque sensors. Multifinger synergies were quantified using the framework of the uncontrolled manifold hypothesis. The elderly participants produced lower force magnitudes by noninstructed fingers and higher force magnitudes by instructed fingers in nontask directions. They showed strong synergies stabilizing the magnitude and direction of the total force vector. However, the synergy indexes were significantly lower than those observed in the earlier study of young subjects. The results are consistent with an earlier hypothesis of preferential weakening of intrinsic hand muscles with age. We interpret the findings as a shift in motor control from synergic to element-based, which may be causally linked to the documented progressive neuronal death at different levels of the neural axis. PMID:20829494

  15. 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.

  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. 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

  18. Integrated data processing of remotely sensed and vector data for building change detection

    NASA Astrophysics Data System (ADS)

    Sofina, N.; Ehlers, M.; Michel, U.

    2012-10-01

    In recent years natural disasters have had an increasing impact leading to tremendous economic and human losses. Remote sensing technologies are being used more often for rapid detection and visualization of changes in the affected areas, providing essential information for damage assessment, planning and coordination of recovery activities. This study presents a GIS-based approach for the detection of damaged buildings. The methodology is based on the integrated analysis of vector data containing information about the original urban layout and remotely sensed images obtained after a catastrophic event. For the classification of building integrity a new `Detected Part of Contour' (DPC) feature was developed. The DPC feature defines a part of the building contour that can be detected in the related remotely sensed image. It reaches maximum value (100%) if the investigated building contour is intact. Next, several features based on the analysis of textural information of the remotely sensed image are considered. Finally, a binary classification of building conditions concludes the change detection analysis. The proposed method was applied to the 2010 earthquake in Qinghai (China). The results indicate that a GIS-based analysis can markedly improve the accuracy of change detection analysis. The proposed methodology has been developed solely within the Open Source Software environment (GRASS GIS, Python, Orange). The employment of Open Source Software provides the way for an innovative, flexible and costeffective implementation of change detection operations.

  19. 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

    2015-04-01

    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. PMID:25688023

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. Characterization Of Ocean Wind Vector Retrievals Using ERS-2 High-Resolution Long-Term Dataset And Buoy Measurements

    NASA Astrophysics Data System (ADS)

    Polverari, F.; Talone, M.; Crapolicchio, R. Levy, G.; Marzano, F.

    2013-12-01

    The European Remote-sensing Satellite (ERS)-2 scatterometer provides wind retrievals over Ocean. To satisfy the needs of high quality and homogeneous set of scatterometer measurements, the European Space Agency (ESA) has developed the project Advanced Scatterometer Processing System (ASPS) with which a long-term dataset of new ERS-2 wind products, with an enhanced resolution of 25km square, has been generated by the reprocessing of the entire ERS mission. This paper presents the main results of the validation work of such new dataset using in situ measurements provided by the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA). The comparison indicates that, on average, the scatterometer data agree well with buoys measurements, however the scatterometer tends to overestimates lower winds and underestimates higher winds.

  7. [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

  8. Changes in wind pattern alter albatross distribution and life-history traits.

    PubMed

    Weimerskirch, Henri; Louzao, Maite; de Grissac, Sophie; Delord, Karine

    2012-01-13

    Westerly winds in the Southern Ocean have increased in intensity and moved poleward. Using long-term demographic and foraging records, we show that foraging range in wandering albatrosses has shifted poleward in conjunction with these changes in wind pattern, while their rates of travel and flight speeds have increased. Consequently, the duration of foraging trips has decreased, breeding success has improved, and birds have increased in mass by more than 1 kilogram. These positive consequences of climate change may be temporary if patterns of wind in the southern westerlies follow predicted climate change scenarios. This study stresses the importance of foraging performance as the key link between environmental changes and population processes. PMID:22246774

  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. 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

  11. 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

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

    PubMed

    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

  13. 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

  14. Multispectral MRI segmentation of age related white matter changes using a cascade of support vector machines.

    PubMed

    Damangir, Soheil; Manzouri, Amirhossein; Oppedal, Ketil; Carlsson, Stefan; Firbank, Michael J; Sonnesyn, Hogne; Tysnes, Ole-Bjørn; O'Brien, John T; Beyer, Mona K; Westman, Eric; Aarsland, Dag; Wahlund, Lars-Olof; Spulber, Gabriela

    2012-11-15

    White matter changes (WMC) are the focus of intensive research and have been linked to cognitive impairment and depression in the elderly. Cumbersome manual outlining procedures make research on WMC labor intensive and prone to subjective bias. We present a fast, fully automated method for WMC segmentation using a cascade of reduced support vector machines (SVMs) with active learning. Data of 102 subjects was used in this study. Two MRI sequences (T1-weighted and FLAIR) and masks of manually outlined WMC from each subject were used for the image analysis. The segmentation framework comprises pre-processing, classification (training and core segmentation) and post-processing. After pre-processing, the model was trained on two subjects and tested on the remaining 100 subjects. The effectiveness and robustness of the classification was assessed using the receiver operating curve technique. The cascade of SVMs segmentation framework outputted accurate results with high sensitivity (90%) and specificity (99.5%) values, with the manually outlined WMC as reference. An algorithm for the segmentation of WMC is proposed. This is a completely competitive and fast automatic segmentation framework, capable of using different input sequences, without changes or restrictions of the image analysis algorithm. PMID:22921728

  15. Comparison of special sensor microwave imager vector wind stress with model-derived and subjective products for the tropical Pacific

    SciTech Connect

    Busalacchi, A.J.; Atlas, R.M. ); Hackert, E.C. )

    1993-04-15

    The authors address the role of wind data in the development of general ocean circulation model studies. Satellite scatterometry has been proposed, but only minimally implemented, as a means of providing global information on ocean surface wind speed and direction. However, a number of microwave systems have monitored wind speed information on a global scale, some over extended periods of time, which provide day-to-day coverage, compared to the sparse information available from ship or buoy data collections. Recently data from the Defense Meteorological Satellite Program special sensor microwave imager, for the period July 1987 to June 1988 was utilized, in conjunction with conventional data collections to build a model system which included wind directions. The authors here take this data set and use it as a forcing function in a general ocean circulation model study. Their interest is in knowing if this gives results comparable with such data sets built from much more limited observational and subjective analysis. The results are encouraging, and they suggest reexamination of earlier information collections with the idea of reconstructing ocean surface wind speed and direction data sets to be used in further modeling studies.

  16. Determination of statistics for any rotation of axes of a bivariate normal elliptical distribution. [of wind vector components

    NASA Technical Reports Server (NTRS)

    Falls, L. W.; Crutcher, H. L.

    1976-01-01

    Transformation of statistics from a dimensional set to another dimensional set involves linear functions of the original set of statistics. Similarly, linear functions will transform statistics within a dimensional set such that the new statistics are relevant to a new set of coordinate axes. A restricted case of the latter is the rotation of axes in a coordinate system involving any two correlated random variables. A special case is the transformation for horizontal wind distributions. Wind statistics are usually provided in terms of wind speed and direction (measured clockwise from north) or in east-west and north-south components. A direct application of this technique allows the determination of appropriate wind statistics parallel and normal to any preselected flight path of a space vehicle. Among the constraints for launching space vehicles are critical values selected from the distribution of the expected winds parallel to and normal to the flight path. These procedures are applied to space vehicle launches at Cape Kennedy, Florida.

  17. Changes in Solar Wind Composition Resulting from CMEs

    NASA Astrophysics Data System (ADS)

    Marchese, A. K.; Espinosa, M.; Campagna, A.; Amador, J.

    2015-12-01

    A coronal mass ejection (CME) is an expulsion of high charged particles from the sun into the solar system. CMEs can damage satellites, endanger astronauts, and affect powerlines on earth, so understanding and predicting CMEs is a priority. It is hypothesized that an incoming intense CME will push the particles in front, increasing the velocity of these particles. Due to conservation of momentum, it is proposed that the lighter elements will have a greater increase in velocity. Data was collected from the SWICS (Solar Wind Ion Composition Spectrometer) instrument on the ACE (Advanced Composition Explorer) satellite and SOHO (Solar and Heliospheric Observatory) and analyzed. It was found that with an increase in the ratio of light elements to heavier elements, such as Helium to Oxygen, an intense CME is likely to occur a few days after. However, not all increases of Helium to Oxygen ratio were associated with a CME, especially if the CME was relatively weak. In addition, a 0.9976 correlation was found between the density of Helium particles and the ratio of Helium to Oxygen. It was found that an increase in velocity of Helium also leads to numerous increases in Helium to Oxygen ratio. These indicators may be used to forecast incoming CMEs.

  18. 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

  19. 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

  20. Supervised Change Detection in VHR Images Using Support Vector Machines and Contextual Information

    NASA Astrophysics Data System (ADS)

    Volpi, Michele; Kanevski, Mikhail

    2010-05-01

    One of the recent challenges in environmental studies is how to include and exploit multitemporal information from multispectral very high resolution (VHR) images. This problem is also known as change detection (CD). Nowadays, many approaches, both supervised and unsupervised, are known and the selection of the method depends strongly on the application, the scope of the study and on available time. In the present research an accurate multiclass supervised method based on Support Vector Machines (SVM) for multitemporal remotely sensed image classification is proposed. SVM is a method issued from the statistical learning theory, known for its good generalization abilities and its performance when dealing with high dimensional spaces. Moreover, its sparse solution provides a final model depending only on a few patterns with an associated nonzero weights (support vectors), and resulting in an optimal regularized complexity. The final decision is obtained with a linear separation of data in an induced kernel feature space, corresponding to a nonlinear classification in the input space. When dealing with CD in VHR imagery, misclassified patterns are often caused by the high variance of the information at pixel level, caused by noise and by the influence of the high spatial resolution. Considering a precise coregistration, the variance at object level is high both in space and in time. The usefulness of adding such information is in smoothing, following an object based or a texture based criteria, the interclass variance and increasing the intraclass variance. By adding such information the classifier can better perform when predicting the class of pixels, because of the neighborhood information that was intrinsically extrapolated by the filtering. In the proposed approach, the behavior of mathematical morphology and morphological profiles obtained with different parameters are studied in a CD setting. The series of features are extracted both on the multispectral images

  1. Surveillance of vector-borne diseases in Germany: trends and challenges in the view of disease emergence and climate change.

    PubMed

    Jansen, Andreas; Frank, Christina; Koch, Judith; Stark, Klaus

    2008-12-01

    The changing epidemiology of vector-borne diseases represents a growing threat to human health. Contemporary surveillance systems have to adapt to these changes. We describe temporal trends and geographic origins of vector-borne diseases in Germany with regard to strengths of existing disease surveillance and to areas marked for improvement. We focused on hantavirus infection (endemic in Germany), chikungunya fever (recently emerging in Europe) and dengue fever (imported from tropical regions), representing important subgroups of vector-borne infections. Routine surveillance data on demographics, origin of infection and the date of reporting were analysed. From 2001 through 2007, 3,005 symptomatic hantavirus infections, and 85 cases of chikungunya fever were reported, similarly 1,048 cases of dengue fever in 2002 through 2007. The geographic origin of hantavirus infection was reported for 95.5% of all cases (dengue virus, 98.4%; chikungunya virus, 100%). Hantavirus infections were acquired in Germany in 97.6% of cases (n = 2800). In 2007, there was a marked increase of hantavirus cases, mainly in areas known to be endemic for hantavirus. In 2006, imported cases of chikungunya fever primarily returned from several islands of the Indian Ocean, while the majority of imported cases in 2007 came from India. The reported number of dengue fever cases have increased since 2004. Thailand contributed the largest proportion of cases (17-43% in individual years), followed by India, Brazil and Indonesia. Surveillance of notifiable vector-borne diseases in Germany is able to timely detect spatial and temporal changes of autochthonous an imported infections. Geographic and temporal data obtained by routine surveillance served as a basis for public health recommendations. In addition to surveillance of vector-borne infections in humans, nationwide monitoring programs and inventory techniques for emerging and reemerging vectors and for wildlife disease are warranted. PMID:19030882

  2. The impact of functional connectivity changes on support vector machines mapping of fMRI data.

    PubMed

    Sato, João Ricardo; Mourão-Miranda, Janaina; Morais Martin, Maria da Graça; Amaro, Edson; Morettin, Pedro Alberto; Brammer, Michael John

    2008-07-15

    Functional magnetic resonance imaging (fMRI) is currently one of the most widely used methods for studying human brain function in vivo. Although many different approaches to fMRI analysis are available, the most widely used methods employ so called "mass-univariate" modeling of responses in a voxel-by-voxel fashion to construct activation maps. However, it is well known that many brain processes involve networks of interacting regions and for this reason multivariate analyses might seem to be attractive alternatives to univariate approaches. The current paper focuses on one multivariate application of statistical learning theory: the statistical discrimination maps (SDM) based on support vector machine, and seeks to establish some possible interpretations when the results differ from univariate approaches. In fact, when there are changes not only on the activation level of two conditions but also on functional connectivity, SDM seems more informative. We addressed this question using both simulations and applications to real data. We have shown that the combined use of univariate approaches and SDM yields significant new insights into brain activations not available using univariate methods alone. In the application to a visual working memory fMRI data, we demonstrated that the interaction among brain regions play a role in SDM's power to detect discriminative voxels. PMID:18499266

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

    PubMed

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

    2011-02-01

    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. PMID:20980005

  4. Changes in measured vector magnetic fields when transformed into heliographic coordinates

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.

    1987-01-01

    The changes that occur in measured magnetic fields when they are transformed into a heliographic coordinate system are investigated. To carry out this investigation, measurements of the vector magnetic field of an active region that was observed at 1/3 the solar radius from disk center are taken, and the observed field is transformed into heliographic coordinates. Differences in the calculated potential field that occur when the heliographic normal component of the field is used as the boundary condition rather than the observed line-of-sight component are also examined. The results of this analysis show: (1) that the observed fields of sunspots more closely resemble the generally accepted picture of the distribution of umbral fields if they are displayed in heliographic coordinates; (2) that the differences in the potential calculations are less than 200 G in field strength and 20 deg in field azimuth outside sunspots; and (3) that differences in the two potential calculations in the sunspot areas are no more than 400 G in field strength but range from 60 to 80 deg in field azimuth in localized umbral areas.

  5. Wind River Changes Its Course: The St. Stephens Experience.

    ERIC Educational Resources Information Center

    Reilly, Robert T.

    1980-01-01

    Describes changes in instructional methods, in techniques of social grouping, and in teacher sensitivity to the cultural and experiential differences that the Shoshoni and Arapaho children bring to the classroom. All have increased attendance and achievement in this reservation school. (IRT)

  6. 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.

  7. 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

  8. 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

  9. Detecting cross-equatorial wind change as a fingerprint of climate response to anthropogenic aerosol forcing

    NASA Astrophysics Data System (ADS)

    Wang, Hai; Xie, Shang-Ping; Tokinaga, Hiroki; Liu, Qinyu; Kosaka, Yu

    2016-04-01

    Anthropogenic aerosols are a major driver of the twetieth century climate change. In climate models, the aerosol forcing, larger in the Northern than Southern Hemispheres, induces an interhemispheric Hadley circulation. In support of the model result, we detected a robust change in the zonal mean cross-equatorial wind over the past 60 years from ship observations and reanalyses, accompanied by physically consistent changes in atmospheric pressure and marine cloud cover. Single-forcing experiments indicate that the observed change in cross-equatorial wind is a fingerprint of aerosol forcing. This zonal mean mode follows the evolution of global aerosol forcing that is distinct from regional changes in the Atlantic sector. Atmospheric simulations successfully reproduce this interhemispheric mode, indicating the importance of sea surface temperature mediation in response to anthropogenic aerosol forcing. As societies awaken to reduce aerosol emissions, a phase reversal of this interhemispheric mode is expected in the 21st century.

  10. 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.

  11. Improving the textural characterization of trabecular bone structure to quantify its changes: the locally adapted scaling vector method

    NASA Astrophysics Data System (ADS)

    Raeth, Christoph W.; Mueller, Dirk; Boehm, Holger F.; Rummeny, Ernst J.; Link, Thomas M.; Monetti, Roberto

    2005-04-01

    We extend the recently introduced scaling vector method (SVM) to improve the textural characterization of oriented trabecular bone structures in the context of osteoporosis. Using the concept of scaling vectors one obtains non-linear structural information from data sets, which can account for global anisotropies. In this work we present a method which allows us to determine the local directionalities in images by using scaling vectors. Thus it becomes possible to better account for local anisotropies and to implement this knowledge in the calculation of the scaling properties of the image. By applying this adaptive technique, a refined quantification of the image structure is possible: we test and evaluate our new method using realistic two-dimensional simulations of bone structures, which model the effect of osteoblasts and osteoclasts on the local change of relative bone density. The partial differential equations involved in the model are solved numerically using cellular automata (CA). Different realizations with slightly varying control parameters are considered. Our results show that even small changes in the trabecular structures, which are induced by variation of a control parameters of the system, become discernible by applying the locally adapted scaling vector method. The results are superior to those obtained by isotropic and/or bulk measures. These findings may be especially important for monitoring the treatment of patients, where the early recognition of (drug-induced) changes in the trabecular structure is crucial.

  12. 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. PMID:21125310

  13. Low-speed wind-tunnel tests of a large scale blended arrow advanced supersonic transport model having variable cycle engines and vectoring exhaust nozzles

    NASA Technical Reports Server (NTRS)

    Parlett, L. P.; Shivers, J. P.

    1976-01-01

    A low-speed wind-tunnel investigation was conducted in a full-scale tunnel to determine the performance and static stability and control characteristics of a large-scale model of a blended-arrow advanced supersonic transport configuration incorporating variable-cycle engines and vectoring exhaust nozzles. Configuration variables tested included: (1) engine mode (cruise or low-speed), (2) engine exit nozzle deflection, (3) leading-edge flap geometry, and (4) trailing-edge flap deflection. Test variables included values of C sub micron from 0 to 0.38, values of angle of attack from -10 degrees to 30 degrees, values of angle of sideslip, from -5 degrees to 5 degrees, and values of Reynolds number, from 3.5 million to 6.8 million.

  14. 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

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

    PubMed

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

    2001-05-01

    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

  16. [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. PMID:25985654

  17. 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…

  18. Interhemispheric Geomagnetic Field Response to Sudden Change in Solar Wind Pressure and IMF Orientation

    NASA Astrophysics Data System (ADS)

    Kim, H.; Cai, X.; Clauer, C. R.; Stolle, C.; Matzka, J.

    2011-12-01

    Preliminary investigation of geomagnetic field response to sudden change in solar wind pressure and IMF orientation is presented using data from satellite and ground magnetometer array in both northern and southern hemispheres. Some data sets in this study have been provided by AGO (Automatic Geophysical Observatory) and AAL-PIP (Autonomous Adaptive Low-Power Instrument Platform) stations deployed in Antarctica along the 40° magnetic meridian. These stations facilitate high-latitude multi-point magnetic conjugate observation pairs to the Greenland West Coast magnetometer chain for interhemispheric investigations, which have been rarely made because of the difficulty in accessing the Antarctic regions. Geomagnetic field perturbations in response to solar wind pressure impulse events, in which the solar wind pressure changes are more than ˜5 nPa in less than ~16 minutes and the pressures are steady for ~1 hour before and ~20 minutes after the pressure changes, have been examined using the data sets obtained from 1998 to 2010 to show global local time distribution of the ground response, timing response between the two hemispheres and its seasonal variation, and the relationship between IMF orientation and the ground response accompanied by the solar wind sudden pressure change.

  19. 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 ...

  20. 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

  1. 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. PMID:26796862

  2. 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

  3. Large warming trends associated with blocked winds over the Antarctic Peninsula and changes in zonal circulation

    NASA Astrophysics Data System (ADS)

    Orr, A.; Hunt, J.; Light, M.; Cresswell, D.

    2003-04-01

    katabatic winds are not (at present) accurately represented. \\vspace{0.1cm} References: \\vspace{0.1cm} Kwok, R. and Comiso, J. C., `Spatial patterns of variability in Antarctic surface temperature: Connections to the Southern Hemisphere Annular Mode and the Southern Oscillation', Geophysical Research Letters, Vol. 29, No. 10, 2002. \\vspace{0.1cm} Hunt, J. C. R., Orr, A., Rottman, J. and Capon, R., `Coriolis effects in mesoscale flows with sharp changes in surface conditions', Submitted to Q. J. Roy. Met. Soc, 2002.

  4. Modelling the historical changes in physical soil properties caused by wind erosion process

    NASA Astrophysics Data System (ADS)

    Lackóová, Lenka

    2016-04-01

    Soil physical properties could be significantly affected by land degradation processes. Spatial variation modelling of physical soil properties in time is important in areas where wind erosion occurs regularly. The objectives of this study were to determine the changes of spatial variability of sand, silt and clay % contents in selected area in Slovakia over 45 years using topsoil physical properties at European scale (using LUCAS topsoil) and historical Complex Soil Survey Data. The Complex Soil Survey was made in the period 1960-1970 for the whole of the Slovak Republic, using a unified methodology to build an important soil properties database including physical topsoil properties. Spatial model distribution using regression kriging algorithm created by Soil Science and Conservation Research Institute was used for comparison with LUCAS topsoil particle size distribution datasets and their derived products of clay, sand and silt % content. The results of this study will show the effects of wind erosion in long time scale. Continual total mass removal during wind erosion can produce dramatic changes in the texture of the soil surface. Fine particles are removed, which tend to concentrate sand as erosion continues. Wind erosion physically removes the most fertile portion of the soil which may lead to lower productivity or destroying the characteristics of topsoil beneficial to plant growth. Historical changes of physical soil properties are discussed in this study.

  5. Change of solar wind quasi-invariant in solar cycle 23—Analysis of PDFs

    NASA Astrophysics Data System (ADS)

    Leitner, M.; Farrugia, C. J.; Vörös, Z.

    2011-02-01

    An in situ solar wind measurement which is a very good proxy for solar activity, correlating well with the sunspot number, is the solar wind “quasi-invariant” (QI), which is defined as the ratio between magnetic and kinetic energy densities. Here we use 1-min OMNI data to determine yearly probability density functions (PDFs) for QI. We distinguish between fast and slow solar winds, and exclude interplanetary coronal mass ejections (ICMEs) from the data, since the latter have a different distribution. Fitting the PDFs by a log-kappa distribution, we discuss the variation of QI in the period 1995-2009, encompassing solar cycle 23 and the long, very quiet minimum in 2007-2009. The additional value of kappa allows us to obtain a better description for the tails of the distribution than the log-normal approach. Here we describe for the first time how parameter kappa changes over one solar cycle.

  6. Climate change projected fire weather sensitivity: California Santa Ana wind occurrence

    NASA Astrophysics Data System (ADS)

    Miller, Norman L.; Schlegel, Nicole J.

    2006-08-01

    A new method based on global climate model pressure gradients was developed for identifying coastal high-wind fire weather conditions, such as the Santa Ana Occurrence (SAO). Application of this method for determining southern California Santa Ana wind occurrence resulted in a good correlation between derived large-scale SAOs and observed offshore winds during periods of low humidity. The projected change in the number of SAOs was analyzed using two global climate models, one a low temperature sensitivity and the other a middle-temperature sensitivity, both forced with low and high emission scenarios, for three future time periods. This initial analysis shows consistent shifts in SAO events from earlier (September-October) to later (November-December) in the season, suggesting that SAOs may significantly increase the extent of California coastal areas burned by wildfires, loss of life, and property.

  7. An improved theory for determining changes in satellite orbits caused by meridional winds

    NASA Astrophysics Data System (ADS)

    King-Hele, D. G.; Walker, Doreen M. C.

    1987-05-01

    Meridional (south-to-north) winds in the upper atmosphere may be specified by the equivalent angular rotation rate, Phi, and previous theories for the effect of meridional winds on satellite orbits have used Phi as the controlling parameter. In this report the theory is developed anew in terms of the parameter M = Phi sec phi, where phi is the latitude. It is shown that in practice M is just as useful as Phi; and M has the advantage of leading to a much simpler and more accurate theory for expressing the changes in orbital inclination and right ascension of an orbit of any eccentricity (e greater than 0 and less than 1) produced by meridional winds in an oblate atmosphere. The theory is developed in two parts: for high eccentricity (e greater than 0.05) and for low eccentricity (e less than 0.05).

  8. 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

  9. A new Global Observational Dataset for Detecting Changes in Surface Winds and Storm Activity

    NASA Astrophysics Data System (ADS)

    Ricciardulli, L.; Wentz, F. J.

    2006-12-01

    Remote Sensing Systems just released a new version of the Special Sensor Microwave Imager (SSM/I) data products. SSM/I is an intercalibrated and unified dataset of continuous satellite observations of surface wind speed, cloud liquid water, water vapor, and rain rate over the global oceans since 1987. In the new Version 6, all six SSM/Is (F08, F10, F11, F13, F14, and F15) have been carefully intercalibrated and a spurious decadal scale trend in wind speed has been corrected. This will now allow investigators to confidently use the SSM/I products for detailed analysis of atmospheric variability at interannual and decadal time scales. Unlike ship data, this satellite dataset provides, for the first time, 19 years of reliable spatially and temporally continuous observations of surface winds (and other cloud-related variables) over the global oceans at 25 km resolution. Here we show global trend maps of surface wind speeds, and analyze in detail patterns in the Atlantic and Pacific extratropical regions. Investigation of changes in storm location is attempted with the aide of rain and cloud liquid water data. A comparison of similar studies we performed using winds from NCEP-NCAR and ERA40 reanalyses, and COADS observations is also addressed.

  10. 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

  11. The role of Southern Ocean winds and CO2 in glacial abrupt climate change

    NASA Astrophysics Data System (ADS)

    Banderas, R.; Alvarez-Solas, J.; Montoya, M.

    2011-12-01

    The last glacial period (ca. 110-10 kyr before present, hereafter kyr BP) is characterized by substantial climate instability, manifested as climatic variability on millennial timescales. Two types of events dominate this variability: Dansgaard-Oeschger (DO) events, which involve decadal-scale warming by more than 10K, and Heinrich events, massive iceberg discharges from the Laurentide Ice Sheet at intervals of ca. 10 kyr during peak glacial conditions. Both DO and Heinrich events are associated with widespread centennial to millennial scale climatic changes, including a synchronous temperature response over the North Atlantic and an anti-phase temperature relationship over Antarctica and most of the Southern Ocean, as revealed by a wealth of deep sea sediments and terrestrial record. Recent studies indicate CO2 changes during deglaciation and, possibly, during glacial abrupt climate changes were preceded by significant increases of Southern Ocean upwelling caused by an enhancement and/or a shift of surface winds over that region. The proposed hypothesis is that periods of halted or reduced North Atlantic deep water (NADW) formation resulted in warming of the Southern Ocean through the bipolar see-saw effect leading to a reorganization of Southern Hemisphere (SH) surface winds, and thereby enhanced upwelling and atmospheric CO2 concentrations. Here, the role of SH surface wind and CO2 changes in the Atlantic meridional overturning circulation (MOC) is analyzed in a coupled climate model of intermediate complexity. We investigate whether changes in the former could eventually trigger an intensification of the Atlantic overturning circulation and a northward shift of NADW formation, which would allow to explain glacial abrupt climate changes as the result of an oscillation which involves the MOC, CO2 and the winds.

  12. Uncovering spider silk nanocrystalline variations that facilitate wind-induced mechanical property changes.

    PubMed

    Blamires, Sean J; Wu, Chao-Chia; Wu, Chung-Lin; Sheu, Hwo-Shuenn; Tso, I-Min

    2013-10-14

    Spider major ampullate (MA) silk varies in mechanical properties when spun in different environments. Amino acid compositional changes induced by variations in MaSp1 and MaSp2 expression, and various biochemical and physiological glandular processes induce silk property variability. Quantifying the contributions of these mechanisms on silk variability may facilitate the development of silk biomimetics. Wind is a medium that induces variations in MA silk mechanics. We exposed the spider Cyclosa mulmeinensis to wind and measured the amino acid composition, tensile mechanics, and crystalline structure of its MA silk using HPLC, tensile tests, and X-ray diffraction. We found the mechanical properties of MA silks from spiders exposed to wind to differ from unexposed spiders. The amino acid compositions did not differ, but X-ray diffraction found a lower crystal density and greater β-sheet alignment relative to the fiber axis in the silks of spiders exposed to wind. We found no evidence that the mechanical property variations were a product of profound changes to the alignment of the protein within the amorphous region. We conclude that variations in the density and alignment of the crystalline β-sheets, probably accompanied by some alignment change in the amorphous region as a result of "stretching" during spinning of the silk, probably explains the mechanical property variations that we found across treatment subgroups. As C. mulmeinensis MA silk increases both in strength and elasticity when the spiders are exposed to wind, bioengineers may consider it as a model for the development of high-performance silk biomimetics. PMID:23947397

  13. Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants

    PubMed Central

    Friedman, Jannice; Barrett, Spencer C. H.

    2009-01-01

    Background The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Scope and Conclusions Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers. PMID:19218583

  14. 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

  15. 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

    2016-01-01

    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

  16. Assessment of change in hydration in women during pregnancy and postpartum with bioelectrical impedance vectors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increases in total body water (TBW) are typical of late-stage pregnancy. Because excessive TBW expansion or contraction can lead to adverse outcomes, a safe non-invasive method for routine assessment of TBW would be useful clinically. Impedance vectors are derived from resistance (R) and reactance...

  17. 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.

  18. 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.

  19. Recent changes in measured wind in the NE Atlantic and variability of correlation with NAO

    NASA Astrophysics Data System (ADS)

    Pirazzoli, P. A.; Tomasin, A.; Ullmann, A.

    2010-10-01

    The paper deals with wind measurements, recorded since the 1950s, at twelve meteorological stations along a transect near the westernmost European border, between 64° and 44° N. Extreme wind speed tends to decrease sharply near the northern boundary (at Reykjavick), near the middle of the study area (at Shannon and Valentia) and near the southern boundary (at Brest and Cap Ferret), to increase at Thorshavn, with less significant trends at the other stations. Average wind speeds confirm the above tendencies, with an additional increasing speed at Lerwick, Kirkwall, Malin Head, Belle-Ile and Cap Ferret. To compare changes in wind activity, the data have been subdivided into three periods: until 1975, 1976-1992 and 1993-2008. Frequencies have been computed also for the "winter" (October to March) period, per quadrants, and for occurrences exceeding the speed of 15 m s-1. At Reykjavick a recent increase in the frequency of strong winds has occurred from various directions. Between 62° N (Thorshavn) and 59° N (Kirkwall) strong wind has been increasing since 1975. Minor changes can be observed at Stornoway, whereas at Malin Head the greatest increase for southerlies and westerlies is observed during the 1976-1992 period. At Belmullet, the frequency of strong southerlies has almost doubled since 1992, while at Shannon and Valentia it remains quite low. Finally at Brest and Belle-Ile, westerlies are predominant among winds >15 m s-1. Important changes in time and latitude appear in the correlation with the NAO (North Atlantic Oscillation) index. The highest correlation coefficients, calculated with monthly or seasonal means between the early 1950s and 1975, are observed from between 58° N (Stornoway) and Iceland, whereas low positive coefficients are reported more south. During the period 1976-1992, when increasing NAO index is predominant, positive correlation improves southwards as far as 54° (Belmullet) with some improvement also at Shannon and Valentia, while it

  20. 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. PMID:26163010

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

    PubMed

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

    2001-04-01

    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. PMID:11355385

  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. 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.

  4. Climate Change and Risk of Leishmaniasis in North America: Predictions from Ecological Niche Models of Vector and Reservoir Species

    PubMed Central

    González, Camila; Wang, Ophelia; Strutz, Stavana E.; González-Salazar, Constantino; Sánchez-Cordero, Víctor; Sarkar, Sahotra

    2010-01-01

    Background Climate change is increasingly being implicated in species' range shifts throughout the world, including those of important vector and reservoir species for infectious diseases. In North America (México, United States, and Canada), leishmaniasis is a vector-borne disease that is autochthonous in México and Texas and has begun to expand its range northward. Further expansion to the north may be facilitated by climate change as more habitat becomes suitable for vector and reservoir species for leishmaniasis. Methods and Findings The analysis began with the construction of ecological niche models using a maximum entropy algorithm for the distribution of two sand fly vector species (Lutzomyia anthophora and L. diabolica), three confirmed rodent reservoir species (Neotoma albigula, N. floridana, and N. micropus), and one potential rodent reservoir species (N. mexicana) for leishmaniasis in northern México and the United States. As input, these models used species' occurrence records with topographic and climatic parameters as explanatory variables. Models were tested for their ability to predict correctly both a specified fraction of occurrence points set aside for this purpose and occurrence points from an independently derived data set. These models were refined to obtain predicted species' geographical distributions under increasingly strict assumptions about the ability of a species to disperse to suitable habitat and to persist in it, as modulated by its ecological suitability. Models successful at predictions were fitted to the extreme A2 and relatively conservative B2 projected climate scenarios for 2020, 2050, and 2080 using publicly available interpolated climate data from the Third Intergovernmental Panel on Climate Change Assessment Report. Further analyses included estimation of the projected human population that could potentially be exposed to leishmaniasis in 2020, 2050, and 2080 under the A2 and B2 scenarios. All confirmed vector and

  5. 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

  6. 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

    2015-06-01

    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. Mapping the interacting winds of Eta Carinae: Changes Across the Apastron

    NASA Astrophysics Data System (ADS)

    Gull, Theodore R.; Madura, T.; Corcoran, M. F.; Hamaguchi, K.; Teodoro, M.

    2014-01-01

    Since the May 2009 servicing mission to repair the Hubble Space Telescope, we have systematically mapped the central 1-2" region of Eta Carinae with the 0.1"-wide, long slit of the Space Telescope Imaging Spectrograph. Six mappings of selected forbidden emission lines began in the late recovery after the 2009.1 periastron event and now extend to phase 0.85 of Eta Carina's 5.54 year period. In addition to the recovery of the high state as depicted by [Fe III] (IP=16.6 eV) strictures and the stabilization of [Fe II] (IP=7.8 eV) features, we see components of at least three wind-blown shells that expand outward at 400 to 500 km/s. Virtually all forbidden emission originates from primary wind structures. The [Fe II] shells, moving at 470 km/s, are primary wind (420 km/s) structures slightly accelerated by the fast secondary wind (Teodoro et al, 2013 ApJ 773, L16T). The [Fe III] arcs, directly photo-ionized by the secondary star, also shift outward with time. Structures in both emissions shift in a general clockwork direction consistent with the derived orbital motion by Gull et al (2009 MNRAS 396, 1308) and revised by Madura et al (2012 MNRAS 420, 2064). With the continued development of the 3D hydrodynamic models we are able to compare the changing structures and determine limits to changes in the mass loss rate over this period of time. Additional mappings, to be obtained by seven additional HST visits, are scheduled at selected orbital phases to follow major changes in ionization structue due to the drop of high ionization to low ionization across the 2014.5 periastron passage. This work is funded by NASA grants to support HST research.

  8. Tracking Changes in Winds and Ocean Currents in the South Atlantic Using Terrigenous Sediments

    NASA Astrophysics Data System (ADS)

    Hemming, S. R.; Goldstein, S. L.; Franzese, A. M.; Rutberg, R. L.; Piotrowski, A. M.

    2002-12-01

    Terrigenous sediments in the ocean can provide constraints on key climate variables such as winds and surface and deep currents. Sediments are brought to the ocean via river runoff, winds and ice, and are redistributed in the ocean by currents. Thus provenance and flux variations reflect the pathways of distribution. Temporal changes in sediment provenance may result from latitudinal wind shifts and ocean current patterns due to climate changes. In the South Atlantic, the pattern of clay minerals in surface sediments tracks the pattern of modern surface currents. Provenance boundaries cross large bathymetric features, indicating that surface currents are the first order control on terrigenous sediment distributions. Surface sediment Sr isotope ratios show systematic variations reflecting the geologic age of the sources. Southward from the Equator, South American sources show a gradient from from old (Brazil Craton) to young (Andes), and this is reflected in the Sr isotopes in proximal sediments. It appears to be possible to separate contributions from wind and surface and deep currents using provenance methods. South of 20oS westerly winds dominate, and South American sources are the most likely aeolian contributions. A counterclockwise gyre composed of the Benguela Current (fed partly by the Agulhas Current from the Indian Ocean), and the Equatorial, Brazil, and Falklands currents dominate the surface currents. Convergence of currents (the Agulhas Retroflection and Malvinas Confluence) produce areas that are potentially sensitive monitors of wind-driven circulation changes. Terrigenous sediment provenance studies in strategically chosen areas are powerful tools to constrain changes in wind, wind driven and deep circulation in paleoceanographic/paleoclimate studies. The Southern Cape Basin illustrates the utility of provenance studies in paleoclimate applications. Ancient continental crust of SE Africa is the source of Mozambique Channel detritus with with very

  9. 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

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

    USGS Publications Warehouse

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

  11. Global effects of changes in wind forcing of Southern Indian Ocean

    SciTech Connect

    Altman, D.B. ); Semtner, A.J. ); Chervin, R.M. )

    1990-01-09

    An identical twin numerical experiment has been performed using the global ocean circulation model of Semtner and Chervin. The wind forcing within a band of 120[degree] East [+-] 45[degrees] and 50[degrees] South [+-] 5[degrees] was varied smoothly in space and time to be approximately 4% greater for the twin run than the original. The twin experiment was run for 60 model days. Within nine days small changes of mass transport of the N. Guiana current were observed. Within 24 days changes appeared in mass transport of Pacific Equatorial Rossby waves, and after 60 days mass transport changes were seen in all ocean basins. Within three days small differences in 160 m (mid-thermocline) temperature appeared in the Atlantic basin. Within thirty days, similar changes were evident globally. Similar results were found for mid-thermocline horizontal velocity. These results imply a predictability limit to the accuracy of ocean circulation models due to rapid communication of wave energy between ocean basins. Changes to Pacific Equatorial Rossby wave transport imply possible effects on El Nino by Southern Indian Ocean winds via oceanic coupling.

  12. Causes of change in Northern Hemisphere winter meridional winds and regional hydroclimate

    NASA Astrophysics Data System (ADS)

    Simpson, Isla R.; Seager, Richard; Ting, Mingfang; Shaw, Tiffany A.

    2016-01-01

    A critical aspect of human-induced climate change is how it will affect precipitation around the world. Broadly speaking, warming increases atmospheric moisture holding capacity, intensifies moisture transports and makes sub-tropical dry regions drier and tropical and mid-to-high-latitude wet regions wetter. Extra-tropical precipitation patterns vary strongly with longitude, however, owing to the control exerted by the storm tracks and quasi-stationary highs and lows or stationary waves. Regional precipitation change will, therefore, also depend on how these aspects of the circulation respond. Current climate models robustly predict a change in the Northern Hemisphere (NH) winter stationary wave field that brings wetting southerlies to the west coast of North America, and drying northerlies to interior southwest North America and the eastern Mediterranean. Here we show that this change in the meridional wind field is caused by strengthened zonal mean westerlies in the sub-tropical upper troposphere, which alters the character of intermediate-scale stationary waves. Thus, a robust and easily understood model response to global warming is the prime cause of these regional wind changes. However, the majority of models probably overestimate the magnitude of this response because of biases in their climatological representation of the relevant waves, suggesting that winter season wetting of the North American west coast will be notably less than projected by the multi-model mean.

  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. Topological Winding Number Change and Broken Inversion Symmetry in a Hofstadter's Butterfly.

    PubMed

    Wang, Peng; Cheng, Bin; Martynov, Oleg; Miao, Tengfei; Jing, Lei; Taniguchi, Takashi; Watanabe, Kenji; Aji, Vivek; Lau, Chun Ning; Bockrath, Marc

    2015-10-14

    Graphene's quantum Hall features are associated with a π Berry's phase due to its odd topological pseudospin winding number. In nearly aligned graphene-hexagonal BN heterostructures, the lattice and orientation mismatch produce a superlattice potential, yielding secondary Dirac points in graphene's electronic spectrum, and under a magnetic field, a Hofstadter butterfly-like energy spectrum. Here we report an additional π Berry's phase shift when tuning the Fermi level past the secondary Dirac points, originating from a change in topological winding number from odd to even when the Fermi-surface electron orbit begins to enclose the secondary Dirac points. At large hole doping inversion symmetry breaking generates a distinct hexagonal pattern in the longitudinal resistivity versus magnetic field and charge density. Major Hofstadter butterfly features persist up to ∼100 K, demonstrating the robustness of the fractal energy spectrum in these systems. PMID:26401645

  15. 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

    2016-01-01

    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

  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. 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).

  18. 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

    2014-08-01

    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 (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. PMID:25104384

  19. 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

  20. 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.

  1. 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.

  2. 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. PMID:25703827

  3. 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

  4. Do changes in the size of mud flocs affect the acoustic backscatter values recorded by a Vector ADV?

    NASA Astrophysics Data System (ADS)

    Rouhnia, Mohamad; Keyvani, Ali; Strom, Kyle

    2014-08-01

    A series of experiments were conducted to examine the effect of mud floc growth on the acoustic back-scatter signal recorded by a Nortek Vector acoustic Doppler velocimeter (ADV). Several studies have shown that calibration equations can be developed to link the backscatter strength with average suspended sediment concentration (SSC) when the sediment particle size distribution remains constant. However, when mud is present, the process of flocculation can alter the suspended particle size distribution. Past studies have shown that it is still unclear as to the degree of dependence of the calibration equation on changes in floc size. Part of the ambiguity lies in the fact that flocs can be porous and rather loosely packed and therefore will not scatter sound waves as a solid particle would. In addition, direct, detailed measurements of floc size have not accompanied experiments examining the dependence of ADV backscatter and suspended sediment concentration. In this set of experiments, direct measurement of the floc size distribution is made with time in a mixing chamber using a floc camera system. A Vector ADV and an OBS are also placed within the tank to measure acoustic backscatter and SSC as the flocs change size with time; concentration in the experiments ranges from 15 to 90 mg/l. Results showed that the growth of mud flocs did influence the SNR recorded by the Vector ADV, and that the sensitivity of the SNR signal to changes in floc size was higher for flocs with diameters less than ≈80 μm (it kr=1 at a diameter of 80 μm). The response of SNR to changes in floc size and SSC was modeled with a modified sonar equation. If properly calibrated, the model was able to capture the functional behavior of SNR with changes in floc size and concentration. Values of the calibration coefficients showed that while changes in floc diameter up to about 80 μm did alter the SNR, the change was less than what would be expected from a similar change in the size of solid

  5. 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; 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.

  6. 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. PMID:27171475

  7. 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

  8. Evolution of dengue in Sri Lanka-changes in the virus, vector, and climate.

    PubMed

    Sirisena, P D N N; Noordeen, F

    2014-02-01

    Despite the presence of dengue in Sri Lanka since the early 1960s, dengue has become a major public health issue, with a high morbidity and mortality. Aedes aegypti and Aedes albopictus are the vectors responsible for the transmission of dengue viruses (DENV). The four DENV serotypes (1, 2, 3, and 4) have been co-circulating in Sri Lanka for more than 30 years. The new genotype of DENV-1 has replaced an old genotype, and new clades of DENV-3 genotype III have replaced older clades. The emergence of new clades of DENV-3 in the recent past coincided with an abrupt increase in the number of dengue fever (DF)/dengue hemorrhagic fever (DHF) cases, implicating this serotype in severe epidemics. Climatic factors play a pivotal role in the epidemiological pattern of DF/DHF in terms of the number of cases, severity of illness, shifts in affected age groups, and the expansion of spread from urban to rural areas. There is a regular incidence of DF/DHF throughout the year, with the highest incidence during the rainy months. To reduce the morbidity and mortality associated with DF/DHF, it is important to implement effective vector control programs in the country. The economic impact of DF/DHF results from the expenditure on DF/DHF critical care units in several hospitals and the cost of case management. PMID:24334026

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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. PMID:20683620

  14. 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.

  15. 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).

  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. Spectral Anisotropy of Elsässer Variables in Two-dimensional Wave-vector Space as Observed in the Fast Solar Wind Turbulence

    NASA Astrophysics Data System (ADS)

    Yan, Limei; He, Jiansen; Zhang, Lei; Tu, Chuanyi; Marsch, Eckart; Chen, Christopher H. K.; Wang, Xin; Wang, Linghua; Wicks, Robert T.

    2016-01-01

    Intensive studies have been conducted to understand the anisotropy of solar wind turbulence. However, the anisotropy of Elsässer variables ({{\\boldsymbol{Z}}}+/- ) in 2D wave-vector space has yet to be investigated. Here we first verify the transformation based on the projection-slice theorem between the power spectral density {{PSD}}2{{D}}({k}\\parallel ,{k}\\perp ) and the spatial correlation function {{CF}}2{{D}}({r}\\parallel ,{r}\\perp ). Based on the application of the transformation to the magnetic field and the particle measurements from the WIND spacecraft, we investigate the spectral anisotropy of Elsässer variables ({{\\boldsymbol{Z}}}+/- ), and the distribution of residual energy {E}{{R}}, Alfvén ratio {R}{{A}}, and Elsässer ratio {R}{{E}} in the ({k}\\parallel ,{k}\\perp ) space. The spectra {{PSD}}2{{D}}({k}\\parallel ,{k}\\perp ) of {\\boldsymbol{B}}, {\\boldsymbol{V}}, and {{\\boldsymbol{Z}}}{major} (the larger of {{\\boldsymbol{Z}}}+/- ) show a similar pattern that {{PSD}}2{{D}}({k}\\parallel ,{k}\\perp ) is mainly distributed along a ridge inclined toward the k⊥ axis. This is probably the signature of the oblique Alfvénic fluctuations propagating outwardly. Unlike those of {\\boldsymbol{B}}, {\\boldsymbol{V}}, and {{\\boldsymbol{Z}}}{major}, the spectrum {{PSD}}2{{D}}({k}\\parallel ,{k}\\perp ) of {{\\boldsymbol{Z}}}{minor} is distributed mainly along the k⊥ axis. Close to the k⊥ axis, | {E}{{R}}| becomes larger while {R}{{A}} becomes smaller, suggesting that the dominance of magnetic energy over kinetic energy becomes more significant at small k∥. {R}{{E}} is larger at small k∥, implying that {{PSD}}2{{D}}({k}\\parallel ,{k}\\perp ) of {{\\boldsymbol{Z}}}{minor} is more concentrated along the k⊥ direction as compared to that of {{\\boldsymbol{Z}}}{major}. The residual energy condensate at small k∥ is consistent with simulation results in which {E}{{R}} is spontaneously generated by Alfvén wave interaction.

  18. 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.

  19. 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

    2015-04-01

    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

  20. Changes in vector species composition and current vector biology and behaviour will favour malaria elimination in Santa Isabel Province, Solomon Islands

    PubMed Central

    2011-01-01

    Background In 2009, Santa Isabel Province in the Solomon Islands embarked on a malaria elimination programme. However, very little is known in the Province about the anopheline fauna, which species are vectors, their bionomics and how they may respond to intensified intervention measures. The purpose of this study was to provide baseline data on the malaria vectors and to ascertain the possibility of successfully eliminating malaria using the existing conventional vector control measures, such as indoor residual spraying (IRS) and long-lasting insecticidal nets (LLIN). Methods Entomological surveys were undertaken during October 2009. To determine species composition and distribution larval surveys were conducted across on the whole island. For malaria transmission studies, adult anophelines were sampled using human landing catches from two villages - one coastal and one inland. Results Five Anopheles species were found on Santa Isabel: Anopheles farauti, Anopheles hinesorum, Anopheles lungae, Anopheles solomonis, and Anopheles nataliae. Anopheles hinesorum was the most widespread species. Anopheles farauti was abundant, but found only on the coast. Anopheles punctulatus and Anopheles koliensis were not found. Anopheles farauti was the only species found biting in the coastal village, it was incriminated as a vector in this study; it fed early in the night but equally so indoors and outdoors, and had a low survival rate. Anopheles solomonis was the main species biting humans in the inland village, it was extremely exophagic, with low survival rates, and readily fed on pigs. Conclusion The disappearance of the two major vectors, An. punctulatus and An. koliensis, from Santa Isabel and the predominance of An. hinesorum, a non-vector species may facilitate malaria elimination measures. Anopheles farauti was identified as the main coastal vector with An. solomonis as a possible inland vector. The behaviour of An. solomonis is novel as it has not been previously found

  1. Introducing Vectors.

    ERIC Educational Resources Information Center

    Roche, John

    1997-01-01

    Suggests an approach to teaching vectors that promotes active learning through challenging questions addressed to the class, as opposed to subtle explanations. Promotes introducing vector graphics with concrete examples, beginning with an explanation of the displacement vector. Also discusses artificial vectors, vector algebra, and unit vectors.…

  2. Short communication on regional climate change scenarios and their possible use for impact studies on vector-borne diseases.

    PubMed

    Jacob, Daniela

    2008-12-01

    Atmospheric observations demonstrate that, during the last decades, the climate has changed. As reported by the Intergovernmental Panel on Climate Change (IPCC, 2001, 2007), a mean increase of temperature by 0.09 K per decade was observed globally from 1951 to 1989. Up to now, 2008, this trend has continued. Europe experienced an extraordinary heat wave in summer 2003, with daily mean temperatures being about 10 degrees warmer than the long-term mean. The increase of temperature varies depending on the region and season. It seems to be accompanied by changes in several hydro-meteorological quantities, like number and duration of heat waves, frost periods, storminess, or precipitation. In some regions of Germany, for example, winter precipitation has increased by more than 30% within the last four decades. In addition, very intense precipitation was observed in summer 2002 in parts of the Elbe drainage basin, which faced a severe flooding. The quantification of these changes and their possible impacts on health is a very important topic, for which regional climate change scenarios provide useful information. The analyses of possible climate change focusing on hydro-meteorological quantities, which have a major influence on vectors and rodent reservoirs will be an ongoing challenge for future research. PMID:19030880

  3. 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.

  4. 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. PMID:23192299

  5. Structural damage localisation for a frame structure from changes in curvature of approximate entropy feature vectors

    NASA Astrophysics Data System (ADS)

    An, Y. H.; Ou, J. P.

    2014-01-01

    At present, accurate vibration-based damage localisation cannot be achieved very well in mechanical and civil engineering fields due to high noise in the measurements and low accuracy in finite element (FE) model of the measured structures. To address these issues, a method for damage detection is proposed in this work, i.e. the mean curvature difference method of approximate entropy (ApEn) feature vectors, based on the ApEn theory and curvature method. Simulation results of both single and multiple damage cases under pulse excitation indicate that the proposed method can be utilised to determine whether the damage is present in the structure or not and to locate the damage accurately, and the method exhibits strong anti-noise ability: it is feasible for damage with 5% stiffness reduction even if the noise level is up to 25%. Moreover, the proposed method does not require a structural FE model. Experimental results of a six-storey shear frame model also validated the proposed method. All of these lay a good foundation for its application in shear frame structures.

  6. 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.

  7. The reality of the secular change in solar wind nitrogen isotopes

    NASA Technical Reports Server (NTRS)

    Kerridge, J. F.

    1986-01-01

    Evidence concerning the isotopic composition of N in the early solar system currently seems to favor a picture of isotopic inhomogeneity rather than of a unique primordial composition modified by local processes. Certainly the range of N-15/N-14 ratios found in meteorites points to the existence of more than one nucleogenetic N component, though mass dependent modification of them explain the isotopic variation observed for N in the lunar regolith. The observational evidence is addressed which can be used to discriminate between such a model and one invoking a secular change in the composition of the solar wind. Three tests of this model were considered, starting with a search for light planetary N surviving in lunar rocks. Results so far are negative. The results of these tests may not eliminate the two component model for regolith N but they seriously weaken it. The alternate view, involving a secular change in solar wind N composition, has its problems but continues to survive by default.

  8. Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)

    NASA Astrophysics Data System (ADS)

    Erickson, R. A.; Hayhoe, K.; Presley, S. M.; Allen, L. J. S.; Long, K. R.; Cox, S. B.

    2012-09-01

    Shifts in temperature and precipitation patterns caused by global climate change may have profound impacts on the ecology of certain infectious diseases. We examine the potential impacts of climate change on the transmission and maintenance dynamics of dengue, a resurging mosquito-vectored infectious disease. In particular, we project changes in dengue season length for three cities: Atlanta, GA; Chicago, IL and Lubbock, TX. These cities are located on the edges of the range of the Asian tiger mosquito within the United States of America and were chosen as test cases. We use a disease model that explicitly incorporates mosquito population dynamics and high-resolution climate projections. Based on projected changes under the Special Report on Emissions Scenarios (SRES) A1fi (higher) and B1 (lower) emission scenarios as simulated by four global climate models, we found that the projected warming shortened mosquito lifespan, which in turn decreased the potential dengue season. These results illustrate the difficulty in predicting how climate change may alter complex systems.

  9. The ionospheric signatures of flux transfer events and solar wind dynamic pressure changes

    NASA Technical Reports Server (NTRS)

    Lockwood, M.; Cowley, S. W. H.; Sandholt, P. E.; Lepping, R. P.

    1990-01-01

    Recent observations of vortical flow patterns in the dayside auroral ionosphere are discussed in terms of two alternative mechanisms: (1) the time-dependent magnetic reconnection in 'flux transfer events' (FTEs); and (2) the action of solar wind dynamic pressure changes at the magnetopause. It is argued that the ionospheric flow signature of an FTE should be a twin vortex, with the mean flow velocity in the central region of the pattern being equal to the velocity of the pattern as a whole. On the other hand, the pulse of enhanced or reduced dynamic pressure is also expected to produce a twin vortex, but with the central plasma flow being generally different in speed from (and almost orthogonal to) the motion of the whole pattern. It is found that, while none of the events discussed here are consistent with the theories of the effects of the dynamic pressure changes, all are well explained in terms of the ionospheric signatures of FTEs.

  10. 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.

  11. Changes in left atrial deformation in hypertrophic cardiomyopathy: Evaluation by vector velocity imaging

    PubMed Central

    Badran, Hala Mahfouz; Soltan, Ghada; Hassan, Hesham; Nazmy, Ahmed; Faheem, Naglaa; Saadan, Haythem; Yacoub, Magdi H.

    2012-01-01

    Abstract: Objectives: Hypertrophic cardiomyopathy (HCM) represents a generalized myopathic process affecting both ventricular and atrial myocardium. We assessed the global and regional left atrial (LA) function and its relation to left ventricular (LV) mechanics and clinical status in patients with HCM using Vector Velocity Imaging (VVI). Methods: VVI of the LA and LV was acquired from apical four- and two-chamber views of 108 HCM patients (age 40 ± 19years, 56.5% men) and 33 healthy subjects, all had normal LV systolic function. The LA subendocardium was traced to obtain atrial volumes, ejection fraction, velocities, and strain (ϵ)/strain rate (SR) measurements. Results: Left atrial reservoir (ϵsys,SRsys) and conduit (early diastolic SRe) function were significantly reduced in HCM compared to controls (P < .0001). Left atrial deformation directly correlated to LVϵsys, SRsys and negatively correlated to age, NYHA class, left ventricular outflow tract (LVOT) gradient, left ventricular mass index (LVMI), LA volume index and severity of mitral regurge (P < 0.001). Receiver operating characterist was constructed to explore the cutoff value of LA deformation in differentiation of LA dysfunction; ϵsys < 40% was 75% sensitive, 50% specific, SRsys < 1.7s− 1 was 70% sensitive, 61% specific, SRe> − 1.8s− 1 was 81% sensitive and 30% specific, SRa> − 1.5s− 1 was 73% sensitive and 40% specific. By multivariate analysis global LVϵsys and LV septal thickness are independent predictors for LAϵsys, while end systolic diameter is the only independent predictor for SRsys, P < .001. Conclusion: Left atrial reservoir and conduit function as measured by VVI were significantly impaired while contractile function was preserved among HCM patients. Left atrial deformation was greatly influenced by LV mechanics and correlated to severity of phenotype. PMID:24688992

  12. 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

  13. 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.

  14. The Structural Changes of Tropical Cyclones Upon Interaction with Vertical Wind Shear

    NASA Technical Reports Server (NTRS)

    Ritchie, Elizabeth A.

    2003-01-01

    The Fourth Convection and Moisture Experiment (CAMEX-4) provided a unique opportunity to observe the distributions and document the roles of important atmospheric factors that impact the development of the core asymmetries and core structural changes of tropical cyclones embedded in vertical wind shear. The state-of-the-art instruments flown on the NASA DC-8 and ER-2, in addition to those on the NOAA aircraft, provided a unique set of observations that documented the core structure throughout the depth of the tropical cyclone. These data have been used to conduct a combined observational and modeling study using a state-of-the-art, high- resolution mesoscale model to examine the role of the environmental vertical wind shear in producing tropical cyclone core asymmetries, and the effects on the structure and intensity of tropical cyclones.The scientific objectives of this study were to obtain in situ measurements that would allow documentation of the physical mechanisms that influence the development of the asymmetric convection and its effect on the core structure of the tropical cyclone.

  15. 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.

  16. 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.

  17. 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.

  18. 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. PMID:27547511

  19. 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

  20. 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.

  1. 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.

  2. Solar-wind-driven changes to the ionospheric electric potential lead to changes in tropospheric temperature and geopotential height

    NASA Astrophysics Data System (ADS)

    Lam, Mai Mai; Chisham, Gareth; Freeman, Mervyn P.

    2015-04-01

    There are a large number of responses, on the day-to-day timescale, of the dynamics of the troposphere to regional changes in the downward current of the global atmospheric electric circuit (GEC). They provide compelling evidence that, via the GEC, the solar wind plays a role in influencing surface weather and climate. We use reanalysis data to estimate the altitude and time lag dependence of one such response - the Mansurov effect. This effect was first observed as a correlation between the duskward component By of the interplanetary magnetic field (IMF) and surface pressure anomalies in Antarctica. Additionally, we have more recently shown that the polar Mansurov effect can affect mid-latitude atmospheric planetary waves, the amplitude of the effect being comparable to typical initial analysis uncertainties in ensemble numerical weather prediction. Here we shed light on the origins of the polar surface effect by examining the correlation between IMF By and geopotential height anomalies throughout the Antarctic troposphere and lower stratosphere. We find that the correlation is highly statistically significant within the troposphere, and not so in the stratosphere. The peak in the correlation occurs at greater time lags at the tropopause (~ 6 - 8 days) and in the mid troposphere (~ 4 days) than in the lower troposphere (~ 1 day). This supports a mechanism involving the action on lower tropospheric clouds of the GEC, modified by variations in the solar wind (through modulations of the spatial variation in ionospheric potential). The increase in time lag with increasing altitude is consistent with the upward propagation by conventional atmospheric processes of the solar wind-induced variability in the lower troposphere. This is in contrast to the downward propagation of atmospheric effects to the lower troposphere from the stratosphere due to solar variability-driven mechanisms involving ultraviolet radiation or energetic particle precipitation. We also find a

  3. 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

    2015-02-01

    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. PMID:25540277

  4. 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...

  5. 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.

  6. 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.

  7. Wind Variability--An Indicator for a Mesoclimatic Change in Israel.

    NASA Astrophysics Data System (ADS)

    Alpert, Pinhas; Mandel, Moshe

    1986-11-01

    It is shown that the normalized diurnal and interdiurnal surface wind variabilities have a clear decreasing trend in central-southern Israel for the last three decades. This trend is found in the surface data of the independent time series of three meteorological stations in this area. It is suggested that this change indicates a mesoscale modification of climate which is induced by the agricultural development and settlement of the central to southern part of Israel in the recent decades. The decreasing trend becomes particularly strong during the 1960s and this is correlated to the enhanced irrigational effects due to the starting-up of the National Water System in 1964. It is proposed that the region may have gone through a similar but reversed mechanism to that of the desertification process (reversed desertification?) that was largely investigated in association with the Sahel zone drought.

  8. 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. PMID:22206348

  9. Acute effects of changes to the gravitational vector on the eye.

    PubMed

    Anderson, Allison P; Swan, Jacob G; Phillips, Scott D; Knaus, Darin A; Kattamis, Nicholas T; Toutain-Kidd, Christine M; Zegans, Michael E; Fellows, Abigail M; Buckey, Jay C

    2016-04-15

    Intraocular pressure (IOP) initially increases when an individual enters microgravity compared with baseline values when an individual is in a seated position. This has been attributed to a headward fluid shift that increases venous pressures in the head. The change in IOP exceeds changes measured immediately after moving from seated to supine postures on Earth, when a similar fluid shift is produced. Furthermore, central venous and cerebrospinal fluid pressures are at or below supine position levels when measured initially upon entering microgravity, unlike when moving from seated to supine postures on Earth, when these pressures increase. To investigate the effects of altering gravitational forces on the eye, we made ocular measurements on 24 subjects (13 men, 11 women) in the seated, supine, and prone positions in the laboratory, and upon entering microgravity during parabolic flight. IOP in microgravity (16.3 ± 2.7 mmHg) was significantly elevated above values in the seated (11.5 ± 2.0 mmHg) and supine (13.7 ± 3.0 mmHg) positions, and was significantly less than pressure in the prone position (20.3 ± 2.6 mmHg). In all measurements,P< 0.001. Choroidal area was significantly increased in subjects in a microgravity environment (P< 0.007) compared with values from subjects in seated (increase of 0.09 ± 0.1 mm(2)) and supine (increase of 0.06 ± 0.09 mm(2)) positions. IOP results are consistent with the hypothesis that hydrostatic gradients affect IOP, and may explain how IOP can increase beyond supine values in microgravity when central venous and intracranial pressure do not. Understanding gravitational effects on the eye may help develop hypotheses for how microgravity-induced visual changes develop. PMID:26662052

  10. 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. PMID:20237508

  11. Climate Change and Vector Borne Diseases: Getting A Grip on Control

    NASA Astrophysics Data System (ADS)

    Glass, G. E.; Ellis, H.

    2011-12-01

    Pathogens that are transmitted by arthropods to humans kill millions of people a year and have long been identified as systems likely affected by climate change. Despite this, there has been a long controversy of how to evaluate the responses of these infectious disease systems to climatic conditions so that meaningful programmatic dcisions can be made. We briefly review the rationale for overall expectations, using them to identify both the temporal and spatial resolution needed for decision making and then discuss progress to date, using the world global malaria eradication program as an example.

  12. 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.

  13. Wind extremes in the North Sea basin under climate change: an ensemble study of 12 CMIP5 GCMs

    NASA Astrophysics Data System (ADS)

    de Winter, R.; Ruessink, G.; Sterl, A.

    2012-12-01

    Coastal safety may be influenced by climate change, as changes in extreme surge levels and wave extremes may increase the vulnerability of dunes and other coastal defenses. In the North Sea, an area already prone to severe flooding, these high surge levels and waves are generated by severe wind speeds during storm events. As a result of the geometry of the North Sea, not only the maximum wind speed is relevant, but also wind direction. Analyzing changes in a changing climate implies that several uncertainties need to be taken into account. First, there is the uncertainty in climate experiments, which represents the possible development of the emission of greenhouse gases. Second, there is uncertainty between the climate models that are used to analyze the effect of different climate experiments. The third uncertainty is the natural variability of the climate. When this system variability is large, small trends will be difficult to detect. The natural variability results in statistical uncertainty, especially for events with high return values. We addressed the first two types of uncertainties for extreme wind conditions in the North Sea using 12 CMIP5 GCMs. To evaluate the differences between the climate experiments, two climate experiments (rcp4.5 and rcp8.5) from 2050-2100 are compared with historical runs, running from 1950-2000. Rcp4.5 is considered to be a middle climate experiment and rcp8.5 represents high-end climate scenarios. The projections of the 12 GCMs for a given scenario illustrate model uncertainty. We focus on the North Sea basin, because changes in wind conditions could have a large impact on safety of the densely populated North Sea coast, an area that has already a high exposure to flooding. Our results show that, consistent with ERA-Interim results, the annual maximum wind speed in the historical run demonstrates large interannual variability. For the North Sea, the annual maximum wind speed is not projected to change in either rcp4.5 or rcp8

  14. 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

  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. 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

    2015-04-01

    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

  17. 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.

  18. 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

  19. 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.

  20. Assessment and Analysis of QuikSCAT Vector Wind Products for the Gulf of Mexico: A Long-Term and Hurricane Analysis

    PubMed Central

    Sharma, Neha; D’Sa, Eurico

    2008-01-01

    The northern Gulf of Mexico is a region that has been frequently impacted in recent years by natural disasters such as hurricanes. The use of remote sensing data such as winds from NASA's QuikSCAT satellite sensor would be useful for emergency preparedness during such events. In this study, the performance of QuikSCAT products, including JPL's latest Level 2B (L2B) 12.5 km swath winds, were evaluated with respect to buoy-measured winds in the Gulf of Mexico for the period January 2005 to February 2007. Regression analyses indicated better accuracy of QuikSCAT's L2B DIRTH, 12.5 km than the Level 3 (L3), 25 km wind product. QuikSCAT wind data were compared directly with buoy data keeping a maximum time interval of 20 min and spatial interval of 0.1° (≈10 km). R2 values for moderate wind speeds were 0.88 and 0.93 for L2B, and 0.75 and 0.89 for L3 for speed and direction, respectively. QuikSCAT wind comparisons for buoys located offshore were better than those located near the coast. Hurricanes that took place during 2002-06 were studied individually to obtain regressions of QuikSCAT versus buoys for those events. Results show QuikSCAT's L2B DIRTH wind product compared well with buoys during hurricanes up to the limit of buoy measurements. Comparisons with the National Hurricane Center (NHC) best track analyses indicated QuikSCAT winds to be lower than those obtained by NHC, possibly due to rain contamination, while buoy measurements appeared to be constrained at high wind speeds. This study has confirmed good agreement of the new QuikSCAT L2B product with buoy measurements and further suggests its potential use during extreme weather conditions in the Gulf of Mexico.

  1. Changing Malaria Prevalence on the Kenyan Coast since 1974: Climate, Drugs and Vector Control

    PubMed Central

    Snow, Robert W.; Kibuchi, Eliud; Karuri, Stella W.; Sang, Gilbert; Gitonga, Caroline W.; Mwandawiro, Charles; Bejon, Philip; Noor, Abdisalan M.

    2015-01-01

    Background Progress toward reducing the malaria burden in Africa has been measured, or modeled, using datasets with relatively short time-windows. These restricted temporal analyses may miss the wider context of longer-term cycles of malaria risk and hence may lead to incorrect inferences regarding the impact of intervention. Methods 1147 age-corrected Plasmodium falciparum parasite prevalence (PfPR2-10) surveys among rural communities along the Kenyan coast were assembled from 1974 to 2014. A Bayesian conditional autoregressive generalized linear mixed model was used to interpolate to 279 small areas for each of the 41 years since 1974. Best-fit polynomial splined curves of changing PfPR2-10 were compared to a sequence of plausible explanatory variables related to rainfall, drug resistance and insecticide-treated bed net (ITN) use. Results P. falciparum parasite prevalence initially rose from 1974 to 1987, dipped in 1991–92 but remained high until 1998. From 1998 onwards prevalence began to decline until 2011, then began to rise through to 2014. This major decline occurred before ITNs were widely distributed and variation in rainfall coincided with some, but not all, short-term transmission cycles. Emerging resistance to chloroquine and introduction of sulfadoxine/pyrimethamine provided plausible explanations for the rise and fall of malaria transmission along the Kenyan coast. Conclusions Progress towards elimination might not be as predictable as we would like, where natural and extrinsic cycles of transmission confound evaluations of the effect of interventions. Deciding where a country lies on an elimination pathway requires careful empiric observation of the long-term epidemiology of malaria transmission. PMID:26107772

  2. Long-term changes in solar wind elemental and isotopic ratios: A compairosn of two lunar ilmenites of different antiquities

    SciTech Connect

    Becker, R.H.; Pepin, R.O. )

    1989-05-01

    An ilmenite separate from lunar regolith breccia 79035, a sample presumed to have been exposed to solar wind more than 2 Ga ago, was analyzed for noble gas and nitrogen elemental and isotopic abundances by stepwise oxidation and pyrolysis. The gases appear to be distributed between two distinct reservoirs in the ilmenite, defined by release patterns and isotopic considerations. One of the reservoirs, near grain surfaces, yields elemental ratios that for the most part are solar while the other, sited at greater depths within grains, has severely fractionated elemental abundances and generally heavier isotopic ratios as well. Xenon provides an exception to the solar abundance pattern in the near-surface reservoir, being enhanced by about a factor of 2 relative to the expected value. A comparison of the 79035 separate with a previously analyzed ilmenite from soil 71501, which received its solar wind exposure much more recently, indicates that the two-fold xenon enhancement occurs in the fractionated reservoir as well as the solar one, and that it may therefore be attributable to a change in the solar wind elemental abundances. Other differences between the two ilmenites occur in helium and neon isotopic ratios and in He/Ar elemental ratios. Since mineralogical influences on retentivities of the gases in the two samples should be the same, and possible contributions of non-solar wind components to one ilmenite in preference to the other can generally be eliminated or accounted for, all of these differences may reflect changes in the solar wind over time.

  3. A century of glacier change in the Wind River Range, WY

    NASA Astrophysics Data System (ADS)

    DeVisser, Mark H.; Fountain, Andrew G.

    2015-03-01

    The Wind River Range spans roughly 200 km along the continental divide in western Wyoming and encompasses at least 269 glaciers and perennial snowfields totaling 34.34 ± 0.13 km2 (2006), including Gannett Glacier, the largest glacier (2.81 km2) in the continental U.S. outside of Washington State. To track changing glacier and perennial snow surface area over the past century we used historic maps, aerial photography, and geologic evidence evident in said imagery. Since the end of the Little Ice Age (~ 1900), when the glaciers retreated from their moraines, to 2006 the ice-covered area shrank by ~ 47%. The main driver of surface area change was air temperature, with glaciers at lower elevations shrinking faster than those at higher elevations. The total contribution of ice wastage to late summer stream flow ranged from 0.4 to 1.5%, 0.9 to 2.8%, 1.7 to 5.4%, and 3.4 to 10.9% in four different watersheds, none of which exceeded 7% glacier cover. Results from previous studies were difficult to include because of differences in interpretation of glacier boundaries, because of poor imagery, or to extensive seasonal snow. These difficulties highlight potential problems in combining data sets from different studies and underscores the importance of reexamining past observations to ensure consistent interpretation.

  4. 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.

  5. Separating the influence of projected changes in air temperature and wind on patterns of sea level change and ocean heat content

    NASA Astrophysics Data System (ADS)

    Saenko, Oleg A.; Yang, Duo; Gregory, Jonathan M.; Spence, Paul; Myers, Paul G.

    2015-08-01

    We present ocean model sensitivity experiments aimed at separating the influence of the projected changes in the "thermal" (near-surface air temperature) and "wind" (near-surface winds) forcing on the patterns of sea level and ocean heat content. In the North Atlantic, the distribution of sea level change is more due to the "thermal" forcing, whereas it is more due to the "wind" forcing in the North Pacific; in the Southern Ocean, the "thermal" and "wind" forcing have a comparable influence. In the ocean adjacent to Antarctica the "thermal" forcing leads to an inflow of warmer waters on the continental shelves, which is somewhat attenuated by the "wind" forcing. The structure of the vertically integrated heat uptake is set by different processes at low and high latitudes: at low latitudes it is dominated by the heat transport convergence, whereas at high latitudes it represents a small residual of changes in the surface flux and advection of heat. The structure of the horizontally integrated heat content tendency is set by the increase of downward heat flux by the mean circulation and comparable decrease of upward heat flux by the subgrid-scale processes; the upward eddy heat flux decreases and increases by almost the same magnitude in response to, respectively, the "thermal" and "wind" forcing. Regionally, the surface heat loss and deep convection weaken in the Labrador Sea, but intensify in the Greenland Sea in the region of sea ice retreat. The enhanced heat flux anomaly in the subpolar Atlantic is mainly caused by the "thermal" forcing.

  6. 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

  7. 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

  8. Reconstructing Holocene changes in the Southern Hemisphere westerly winds: Integrating modern processes and paleoclimate data from New Zealand's southern fjords

    NASA Astrophysics Data System (ADS)

    Hinojosa, J.; Moy, C. M.; Wilson, G. S.; Stirling, C. H.

    2013-12-01

    The Southern Hemisphere westerly winds are an important component of the global carbon cycle due to their influence on Southern Ocean CO2 flux. In addition, the winds influence mid-latitude storm tracks, thereby controlling moisture balance over much of New Zealand's South Island and other Southern Hemisphere regions. Fiordland, New Zealand is an ideal locale to investigate Holocene changes in westerly wind behavior: It sits at the northern margin of the wind field maximum, is sensitive to latitudinal and strength fluctuations of the winds, and is the location of numerous fjord sub-basins with high sedimentation rates (up to 3 mm/yr). Due to the strong positive relationship between wind speed and regional rainfall, reconstructions of past precipitation and fjord circulation can inform us of past westerly wind behavior. These processes can be observed through changes in the rate of organic carbon delivery from land: When precipitation is high, more terrestrial organic carbon is delivered to the fjords, while low precipitation shifts the balance toward accumulation of marine organic carbon. An important first step towards reconstructing past westerly wind variability is to characterize the distribution and cycling of carbon throughout different depositional settings in the fjords to determine the optimal location for the development of paleoclimate records. Here, we present a geochemical characterization of surface sediments and the water column throughout the region and apply this understanding to sediment cores. During three field seasons in 2012 and 2013, we collected surface sediments, particulate organic matter, and piston cores from 10 different fjords spanning 44-46° S. Our results suggest that organic carbon in the fjord basins largely follows a two-end-member mixing model, drawing from marine and terrestrial end-member sources. We see consistent down-fjord trends in carbon and nitrogen concentrations and isotopes measured from surface sediments and

  9. Late-glacial to holocene changes in winds, upwelling, and seasonal production of the northern California current system

    USGS Publications Warehouse

    Sancetta, C.; Lyle, M.; Heusser, L.; Zahn, R.; Bradbury, J.P.

    1992-01-01

    A core 120 km off the coast of southern Oregon was examined for changes in lithology, diatoms, and pollen over the past 30,000 yr. Primary production during the late Pleistocene was about half that of the Holocene. Evidence from diatoms and pollen indicates that summer upwelling was much weaker, implying an absence of strong northerly winds. Early Pliocene diatoms found throughout the late Pleistocene section were probably derived from diatomites east of the Cascades and provide evidence for strong easterly winds over a dry continental interior. The findings verify predictions of a climate model based on glacial maximum conditions. There is no compelling evidence for a climatic reversal corresponding to the European Younger Dryas chron. During the early Holocene (9000-7000 yr B.P.) there may have been years when winds were insufficiently strong to support upwelling, so that warm stratified waters lay closer to the coast. ?? 1992.

  10. Late-glacial to holocene changes in winds, upwelling, and seasonal production of the northern California current system

    NASA Astrophysics Data System (ADS)

    Sancetta, Constance; Lyle, Michell; Heusser, Linda; Zahn, Rainer; Bradbury, J. Platt

    1992-11-01

    A core 120 km off the coast of southern Oregon was examined for changes in lithology, diatoms, and pollen over the past 30,000 yr. Primary production during the late Pleistocene was about half that of the Holocene. Evidence from diatoms and pollen indicates that summer upwelling was much weaker, implying an absence of strong northerly winds. Early Pliocene diatoms found throughout the late Pleistocene section were probably derived from diatomites east of the Cascades and provide evidence for strong easterly winds over a dry continental interior. The findings verify predictions of a climate model based on glacial maximum conditions. There is no compelling evidence for a climatic reversal corresponding to the European Younger Dryas chron. During the early Holocene (9000-7000 yr B.P.) there may have been years when winds were insufficiently strong to support upwelling, so that warm stratified waters lay closer to the coast.

  11. 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.

  12. The ionospheric signatures of flux transfer events and solar wind dynamic pressure changes

    SciTech Connect

    Lockwood, M. Imperial College, London ); Cowley, S.W.H. ); Sandholt, P.E. ); Lepping, R.P. )

    1990-10-01

    The generation of flow and current vortices in the dayside auroral ionosphere has been predicted for two processes occurring at the dayside magnetopause. The first of these mechanisms is time-dependent magnetic reconnection, in flux transfer events (FTEs); the second is the action of solar wind dynamic pressure changes. The ionospheric flow signature of an FTE should be a twin vortex, with the mean flow velocity in the central regon of the pattern equal ot the velocity of the pattern as a whole. On the other hand, a pulse of enhanced or reduced dynamic pressure is also expected to produce a twin vortex, but with the central plasma flow being generally different in speed from, and almost orthogonal to, the motion of the whole pattern. In this paper, the authors make use of this distinction to discuss recent observations of vortical flow patterns in the dayside auroral ionosphere in terms of one or other of the proposed mechanisms. They conclude that some of the observatons reported are consistent only with the predicted signature of FTEs. They then evaluate the dimensions of the open flux tubes required to explain some recent simultaneous radar and auroral observatons and infer that they are typically 300 km in north-south extent but up to 2,000 km in longitudinal extent (i.e., roughly 5 hours of MLT). Hence these observations suggest that recent theories of FTEs which invoke time-varying reconnecton at an elongated neutral line may be correct.

  13. Statistical-dynamical downscaling for wind energy potentials: Evaluation and applications to decadal hindcasts and climate change projections

    NASA Astrophysics Data System (ADS)

    Reyers, Mark; Pinto, Joaquim G.; Moemken, Julia

    2015-04-01

    A statistical-dynamical downscaling (SDD) approach for the regionalisation of wind energy output (Eout) over Europe with special focus on Germany is proposed. SDD uses an extended circulation weather type (CWT) analysis on global daily MSLP fields with the central point being located over Germany. 77 weather classes based on the associated circulation weather type and the intensity of the geostrophic flow are identified. Representatives of these classes are dynamical downscaled with the regional climate model COSMO-CLM. By using weather class frequencies of different datasets the simulated representatives are recombined to probability density functions (PDFs) of near-surface wind speed and finally to Eout of a sample wind turbine for present and future climate. This is performed for reanalysis, decadal hindcasts and long-term future projections. For evaluation purposes results of SDD are compared to wind observations and to simulated Eout of purely dynamical downscaling (DD) methods. For the present climate SDD is able to simulate realistic PDFs of 10m-wind speed for most stations in Germany. The resulting spatial Eout patterns are similar to DD simulated Eout. In terms of decadal hindcasts results of SDD are similar to DD simulated Eout over Germany, Poland, Czech Republic, and Benelux, for which high correlations between annual Eout timeseries of SDD and DD are detected for selected hindcasts. Lower correlation is found for other European countries. It is demonstrated that SDD can be used to downscale the full ensemble of the MPI-ESM decadal prediction system. Long-term climate change projections in SRES scenarios of ECHAM5/MPI-OM as obtained by SDD agree well to results of other studies using DD methods, with increasing Eout over Northern Europe and a negative trend over Southern Europe. Despite some biases it is concluded that SDD is an adequate tool to assess regional wind energy changes in large model ensembles.

  14. Spatially-Explicit Simulation Modeling of Ecological Response to Climate Change: Methodological Considerations in Predicting Shifting Population Dynamics of Infectious Disease Vectors.

    PubMed

    Dhingra, Radhika; Jimenez, Violeta; Chang, Howard H; Gambhir, Manoj; Fu, Joshua S; Liu, Yang; Remais, Justin V

    2013-09-01

    Poikilothermic disease vectors can respond to altered climates through spatial changes in both population size and phenology. Quantitative descriptors to characterize, analyze and visualize these dynamic responses are lacking, particularly across large spatial domains. In order to demonstrate the value of a spatially explicit, dynamic modeling approach, we assessed spatial changes in the population dynamics of Ixodes scapularis, the Lyme disease vector, using a temperature-forced population model simulated across a grid of 4 × 4 km cells covering the eastern United States, using both modeled (Weather Research and Forecasting (WRF) 3.2.1) baseline/current (2001-2004) and projected (Representative Concentration Pathway (RCP) 4.5 and RCP 8.5; 2057-2059) climate data. Ten dynamic population features (DPFs) were derived from simulated populations and analyzed spatially to characterize the regional population response to current and future climate across the domain. Each DPF under the current climate was assessed for its ability to discriminate observed Lyme disease risk and known vector presence/absence, using data from the US Centers for Disease Control and Prevention. Peak vector population and month of peak vector population were the DPFs that performed best as predictors of current Lyme disease risk. When examined under baseline and projected climate scenarios, the spatial and temporal distributions of DPFs shift and the seasonal cycle of key questing life stages is compressed under some scenarios. Our results demonstrate the utility of spatial characterization, analysis and visualization of dynamic population responses-including altered phenology-of disease vectors to altered climate. PMID:24772388

  15. Analysis of Change in the Wind Speed Ratio according to Apartment Layout and Solutions

    PubMed Central

    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. PMID:24688430

  16. On the correlation between the fast solar wind flow changes and substorm occurrence

    NASA Astrophysics Data System (ADS)

    Semenov, V. S.; Kubyshkina, D. I.; Kubyshkina, M. V.; Kubyshkin, I. V.; Partamies, N.

    2015-07-01

    There is a point of view that solar wind factors, which break the magnetotail symmetry, are more effective in triggering the magnetospheric substorm. To clarify the question we use a database of substorm onsets and found the evident dependence of the substorm probability on the solar wind flow direction jumps (asymmetric factor), while distribution of the substorm occurrence on the solar wind number density jumps (symmetric factor) is homogeneous. The theoretical interpretation is based on the extension of the existing symmetric Kan model for a bent current sheet. Allowing the model tilt angle to vary in time, we found that the induced electric field penetrates to the central region of the bent current sheet. If the solar wind direction jump increases the bending, then induced electric field thins the current sheet and thus stimulates the reconnection. In the opposite case the current sheet thickens. We claim that this effect is sufficient (provides twice or more thinning of the current sheet in 10 min).

  17. Impact of Global Climate Changes on the Wind Power Density in Brazil

    NASA Astrophysics Data System (ADS)

    Martins, Fernando; Pereira, Enio; Pes, Marcelo; Segundo, Eliude; Lyra, Andr

    The potential onshore wind power resources in Brazil could reach more than 145,000 MW. Brazil's wind energy production has risen up from 22 MW in 2003 to 602 MW in 2009 thanks to the government policy and incentives to encourage the use of wind power and other renewable sources of energy. An additional 256.4 MW is now under construction and should start the op-eration at the end of 2010. Recently 71 additional projects have been approved as a result of the first wind-only bidding round for energy supply in Brazil of December 2009. The contracts, to-taling 1800MW, will start in July 2012 with a supply period of 20 years. Developing wind power in Brazil will help the country to meet its strategic objectives of enhancing energy security and reducing the country's energy-related greenhouse gas emissions. In spite of this, the long-term growth of the national wind capacity depends not only on a more competitive price for this en-ergy source (today at US84, 8M W h)butalsoonthesustainabledomesticdevelopmentof thistechnology.F urth controldatascreeningprocesstoselectvalidclimatologicaltimeseriesf ollowedbytheKendalltrendtestat95

  18. Wind Engineering

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Dr. Jack Cermak, Director of Fluid Dynamics and Diffusion Laboratory, developed the first wind tunnel to simulate the changing temperatures, directions and velocities of natural winds. In this work, Cermak benefited from NASA technology related to what is known as the atmospheric boundary layer (ABL).

  19. 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.

  20. Changes in the onset and intensity of wind-driven upwelling and downwelling along the North American Pacific coast

    NASA Astrophysics Data System (ADS)

    Bylhouwer, Brian; Ianson, Debby; Kohfeld, Karen

    2013-05-01

    The timing, duration, and intensity of wind-driven upwelling and downwelling along the North American Pacific coast play an integral role in coastal circulation and basinwide ecosystem composition. It has been suggested that global warming will cause changes in these winds. Here we develop a new set of objective criteria to unambiguously determine the onset, duration, and intensity of upwelling and downwelling seasons due to local wind forcing. We use these criteria to examine and better characterize temporal trends in wind-driven coastal currents over the previous 60 years and relate them to global warming and large-scale climate oscillations in the coastal ocean between northern California and Vancouver Island (37°N and 51°N). We find an exceptionally variable onset of upwelling at all locations. Some significant temporal trends are found in summer onset and upwelling intensity time series near the Juan de Fuca Strait and off the coast of Oregon. Positive phases of the Pacific Decadal Oscillation are correlated to later and shorter upwelling seasons with weaker upwelling. Warm phases of the El Niño Southern Oscillation are associated with a later onset of summer upwelling south of Oregon and with more intense downwelling throughout the study area. Our analysis identifies strong interannual to interdecadal variability, and emphasizes the importance of time series length when isolating physical temporal trends influenced by large-scale oscillatory behavior of the climate.

  1. 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. PMID:24794388

  2. 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

  3. 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

    2015-04-01

    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

  4. Wind machine

    SciTech Connect

    Gaston, E. E.

    1985-01-15

    To generate power from wind economically, a feathering vane is pivotally mounted perpendicular to a tail vane and shifts the orientation of a sprocket assembly controlled by the tail vane in response to wind velocity. The sprocket assembly changes the orientation of blades which orbit about and rotate the main power shaft so that, as wind velocity changes, the blade orientations are shifted in a compensating direction under the control of the tail vane. A lever shifts the position of the blades to positions that balance wind power and brake the rotation for maintenance purposes. The speed-control mechanism includes a damper to avoid being excessively affected by wind gusts. The main shaft is connected through a speed increaser which has less mass at the high-speed end than the low-speed end to an induction generator when used for cogeneration, the field of the induction generator being excited by the cogeneration frequency.

  5. Future changes of wind energy potentials over Europe in a large CMIP5 multi-model ensemble

    NASA Astrophysics Data System (ADS)

    Moemken, Julia; Reyers, Mark; Pinto, Joaquim G.

    2016-04-01

    A statistical-dynamical downscaling method is used to estimate future changes of wind energy output (Eout) of a benchmark wind turbine across Europe at the regional scale. With this aim, 22 global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble are considered. The downscaling method uses circulation weather types and regional climate modelling with the COSMO-CLM model. Future projections are computed for two time periods (2021-2060 and 2061-2100) following two scenarios (RCP4.5 and RCP8.5). The CMIP5 ensemble mean response reveals a more likely than not increase of mean annual Eout over Northern and Central Europe and a likely decrease over Southern Europe. There is some uncertainty with respect to the magnitude and the sign of the changes. Higher robustness in future changes is observed for specific seasons. Except from the Mediterranean area, an ensemble mean increase of Eout is simulated for winter and a decreasing for the summer season, resulting in a strong increase of the intra-annual variability for most of Europe. The latter is, in particular, probable during the second half of the 21st century under the RCP8.5 scenario. In general, signals are stronger for 2061-2100 compared to 2021-2060 and for RCP8.5 compared to RCP4.5. Regarding changes of the inter-annual variability of Eout for Central Europe, the future projections strongly vary between individual models and also between future periods and scenarios within single models. This study showed for an ensemble of 22 CMIP5 models that changes in the wind energy potentials over Europe may take place in future decades. However, due to the uncertainties detected in this research, further investigations with multi-model ensembles are needed to provide a better quantification and understanding of the future changes.

  6. Future changes of wind energy potentials over Europe in a large CMIP5 multi-model ensemble

    NASA Astrophysics Data System (ADS)

    Reyers, Mark; Moemken, Julia; Pinto, Joaquim G.

    2015-04-01

    A statistical-dynamical downscaling method is used to estimate future changes of wind energy output (Eout) of an idealized wind turbine across Europe at the regional scale. With this aim, 22 GCMs of the CMIP5 ensemble are considered. The downscaling method uses circulation weather types and regional climate modelling with the COSMO-CLM model. Future projections are computed for two time periods (2021-2060 and 2061-2100) following two scenarios (RCP4.5 and RCP8.5). The CMIP5 ensemble mean response reveal a more likely than not increase of mean annual Eout over Northern and Central Europe and a likely decrease over Southern Europe. There is some uncertainty with respect to the magnitude and the sign of the changes. Higher robustness in future changes is observed for specific seasons. Except from the Mediterranean area, an ensemble mean increase of Eout is simulated for winter and a decreasing for the summer season, resulting in a strong increase of the intra-annual variability for most of Europe. The latter is in particular likely during the 2nd half of the 21st century under the RCP8.5 scenario. In general, signals are stronger for 2061-2100 compared to 2021-2060 and for RCP8.5 compared to RCP4.5. Regarding changes of the inter-annual variability of Eout for Central Europe, the future projections strongly vary between individual models and also between future periods and scenarios within single models. This study showed for an ensemble of 22 CMIP5 models that changes in the wind energy potentials over Europe may take place in future decades. However, due to the uncertainties detected in this research, further investigations with multi-model ensembles are needed to provide a better quantification and understanding of the future changes.

  7. 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.

  8. Epidemiological impact of vector control. I. Incidence and changes in prevalence and intensity of Onchocerca volvulus infection.

    PubMed

    De Sole, G; Remme, J; Dadzie, K Y

    1990-01-01

    Since 1974, the Onchocerciasis Control Programme (OCP) has been engaged in a large scale attempt to control the savanna species of the vector of onchocerciasis in seven West African countries. The effect of the vector control effort has been measured by epidemiological evaluation. For this purpose 474 villages have been examined by means of skin snip surveys between 1975 and 1983 and of these, 184 have been retained to-date for follow-up surveys which have documented over the years the reduction of the parasite population. The latest results of the epidemiological evaluation clearly demonstrate an outstanding success of the vector control campaign. The parasite has been or is close to being eliminated from the hyperendemic foci of the core area of the Programme. Major improvements have been registered in the reinvaded areas located at the Western and Eastern borders of the Programme. A major improvement has been found along the river Marahoué, the only focus of the intermediate area between the savanna and the forest where at the previous survey, the endemic situation was still similar to the pre-control situation. The exceptions to this gratifying picture are foci along the Dienkoa and Kulpawn rivers, both located in the core area, where transmission has relapsed and several more years of an effective vector control will be needed to eliminate the local parasite population. PMID:2378200

  9. 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.

  10. Bats in a Mediterranean Mountainous Landscape: Does Wind Farm Repowering Induce Changes at Assemblage and Species Level?

    PubMed

    Ferri, Vincenzo; Battisti, Corrado; Soccini, Christiana

    2016-06-01

    We reported data on flying bat assemblages in a Mediterranean mountain landscape of central Italy on a 5-year time span (2005-2010) where a wind farm repowering has been carried out (from 2009, 17 three-blade turbines substituted an a priori set of one-blade turbines). In 4 yearly based surveys, we calculated a set of univariate metrics at species and assemblage level and also performing a diversity/dominance analysis (k-dominance plots) to evaluate temporal changes. Nine species of bats were present (eight classified at species level, one at genus level). Number of detected taxa, Margalef richness, and Shannon-Wiener diversity apparently decreased between 2005-2007 (one-blade turbine period) and 2009-2010 (three-blade turbines period). We showed a weak temporal turnover only between 2007 and 2009. In k-dominance plots, the occurrence curves of the years before the new wind farming activity (2005 and 2007) were lower when compared to the curves related to the 2009 and 2010 years, suggesting an apparent stress at assemblage level in the second period (2009 and 2010). Myotis emarginatus and Pipistrellus pipistrellus significantly changed their relative frequency during the three-blade wind farming activity, supporting the hypothesis that some bats may be sensitive to repowering. Further research is necessary to confirm a possible sensitivity also for locally rare bats (Miniopterus schreibersii and Plecotus sp.). PMID:26952112

  11. Bats in a Mediterranean Mountainous Landscape: Does Wind Farm Repowering Induce Changes at Assemblage and Species Level?

    NASA Astrophysics Data System (ADS)

    Ferri, Vincenzo; Battisti, Corrado; Soccini, Christiana

    2016-06-01

    We reported data on flying bat assemblages in a Mediterranean mountain landscape of central Italy on a 5-year time span (2005-2010) where a wind farm repowering has been carried out (from 2009, 17 three-blade turbines substituted an a priori set of one-blade turbines). In 4 yearly based surveys, we calculated a set of univariate metrics at species and assemblage level and also performing a diversity/dominance analysis ( k-dominance plots) to evaluate temporal changes. Nine species of bats were present (eight classified at species level, one at genus level). Number of detected taxa, Margalef richness, and Shannon-Wiener diversity apparently decreased between 2005-2007 (one-blade turbine period) and 2009-2010 (three-blade turbines period). We showed a weak temporal turnover only between 2007 and 2009. In k-dominance plots, the occurrence curves of the years before the new wind farming activity (2005 and 2007) were lower when compared to the curves related to the 2009 and 2010 years, suggesting an apparent stress at assemblage level in the second period (2009 and 2010). Myotis emarginatus and Pipistrellus pipistrellus significantly changed their relative frequency during the three-blade wind farming activity, supporting the hypothesis that some bats may be sensitive to repowering. Further research is necessary to confirm a possible sensitivity also for locally rare bats ( Miniopterus schreibersii and Plecotus sp.).

  12. 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.

  13. 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.

  14. 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.

  15. The changing wind structure of the WR/LBV star in HD 5980

    NASA Astrophysics Data System (ADS)

    Koenigsberger, Gloria

    2013-10-01

    HD 5980 is an extraordinary system of massive stars that is located in the Small Magellanic Cloud. It contains an eclipsing binary {P=19.3 d} consisting of a luminous blue variable {LBV} and its Wolf-Rayet {WR} companion. The LBV underwent a major eruptive event in 1994 during which its bolometric luminosity increased by a factor of 5 and it is currently approaching its minimum state of activity. The primary objective of this proposal is to determine the wind velocity and mass-loss rate of the LBV in its current state. With these observations and our earlier observations and analyses, HD 5980 offers the unprecedented opportunity of deriving all the fundamental parameters of an LBV system throughout its activity cycle, parameters which are required in order to constrain the sources of the instabilities that lead to the eruptive phenomena. To accomplish these goals, we request 2 HST orbits to observe HD 5980 with STIS in order to obtain one set of FUV MAMA and CCD spectra at the eclipse, when the LBV occults its WR companion.The study of HD 5980 and the UV spectrum that we propose to acquire are relevant to a broad range of problems including wind-wind collision phenomena, the formation of circumstellar structures powered by stellar winds and the evolution of supernova progenitors.

  16. 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

  17. 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.

  18. Vector Video

    NASA Astrophysics Data System (ADS)

    Taylor, David P.

    2001-01-01

    Vector addition is an important skill for introductory physics students to master. For years, I have used a fun example to introduce vector addition in my introductory physics classes based on one with which my high school physics teacher piqued my interest many years ago.

  19. 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.

  20. 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.

  1. 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

  2. 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. PMID:25747360

  3. 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.

  4. 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.

  5. 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

  6. 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…

  7. Vector quantization

    NASA Technical Reports Server (NTRS)

    Gray, Robert M.

    1989-01-01

    During the past ten years Vector Quantization (VQ) has developed from a theoretical possibility promised by Shannon's source coding theorems into a powerful and competitive technique for speech and image coding and compression at medium to low bit rates. In this survey, the basic ideas behind the design of vector quantizers are sketched and some comments made on the state-of-the-art and current research efforts.

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

    SciTech Connect

    Friis-Christensen, E.; McHenry, M.A.; Clauer, C.R.; Vennerstroem, S.

    1988-03-01

    Analysis of 20-second resolution magnetometer data from an array of temporary stations operated around Soendre Stroemfjord, 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 current 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. copyright American Geophysical Union 1988

  9. 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.

  10. Hot gas ingestion test results of a two-poster vectored thrust concept with flow visualization in the NASA Lewis 9- by 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.

    1990-01-01

    A 9.2 percent scale STOVL hot gas ingestion model was tested in the NASA Lewis 9 x 15-foot Low-Speed Wind Tunnel. 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 test was conducted at full scale nozzle pressure ratios and inlet Mach numbers. 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 and 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, the model airframe heating, and the location of the ground flow separation.

  11. 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

  12. 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; 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.

  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. 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

  15. The Response of Trade-wind Clouds to a Changing Environment: Why Climate Model Cloud Feedbacks Might Differ from Nature?

    NASA Astrophysics Data System (ADS)

    Nuijens, L.; Medeiros, B.; Sandu, I.; Ahlgrimm, M.

    2014-12-01

    The vertical distribution of clouds in the trades, and how this distribution is linked to the thermodynamic structure of the lower troposphere, is emerging as a key factor in the assessment of modeled cloud feedbacks. The spread in cloud feedbacks and climate sensitivity may be attributed to how efficiently models dry the lower troposphere as climate warms. This relates to how models mix moisture vertically, and thus to how their clouds are distributed. A three year record of cloudiness and boundary layer structure from a ground-based remote sensing station at Barbados, situated in a typical trade-wind region, is used to gain insight into the major components of the cloud distribution, and how these vary with changes in atmospheric structure. These insights are then used to evaluate modeled cloud behavior in single time step (half-hourly) output of the ECMWF IFS and CMIP5 models, at a grid point nearby Barbados. Cloudiness is found to be regulated by two components with a different sensitivity to the large-scale flow. Cloud near cloud base is on average the largest contributor to cloudiness, but is relatively constant on time scales much longer than a day. This is because turbulence and cumulus convection adjust fast to perturbations, and self-regulate the cumulus mass flux and cloudiness near cloud base. A secondary component consists mainly of stratiform outflow layers near the detrainment level of cumulus tops, which carry most of the variability on longer time scales. The organization of convection into larger and deeper clusters, which can vertically transport large amounts of moisture, appear key in regulating such outflow layers. Several models fail at reproducing these smaller scale processes that control trade-wind cloudiness in the current climate. The stratiform component in modeled distributions of trade-wind cloudiness is seldom pronounced, and their distributions tend to be bottom-heavy. Whereas observations suggest that changes in clouds are more

  16. 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.

  17. Southern Annular Mode and westerly-wind-driven changes in Indian-Atlantic exchange mechanisms

    NASA Astrophysics Data System (ADS)

    Loveday, B. R.; Penven, P.; Reason, C. J. C.

    2015-06-01

    The dynamical link between the Indian Ocean and Atlantic Meridional Overturning Circulation (AMOC) remains poorly understood. This partly arises from the complex Agulhas leakage, which occurs via rings, cyclones, and non-eddy flux. Hindcast simulations suggest that leakage has recently increased but have not decomposed this signal into its constituent mechanisms. Here these are isolated in a realistic ocean model. Increases in simulated leakage are attributed to stronger eddy and non-eddy-driven transports, and a strong warming and salinification, especially within Agulhas rings. Variability in both regimes is associated with strengthening Indian Ocean westerly winds, reflecting an increasingly positive Southern Annular Mode. While eddy and non-eddy flux signals are tied through turbulent eddy dissipation, the ratio between the two varies decadally. Consequently, while altimetry suggests a recent increase in retroflection turbulence and implied leakage, non-eddy flux may also play a significant role in modulating the leakage AMOC connection.

  18. 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

    2013-09-01

    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. PMID:24009386

  19. 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

  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. 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.

  2. A device for rapid determination of thermophysical properties of phase-change wind-tunnel models

    NASA Technical Reports Server (NTRS)

    Creel, T. R., Jr.

    1976-01-01

    An experimental method for direct measurement of the thermophysical properties of wind tunnel heat transfer models was developed. The technique consists of placing the model under a bank of high intensity, radiant heaters so that the fast opening water cooled shutters, which isolate the heater bank from the model, allow a step-input heat rate to be applied. Measurements of the heat transfer rate coupled with a surface-temperature time history of the same material are sufficient to determine the material thermophysical properties. An infrared thermometer is used to measure model surface temperature and a slug calorimeter provides heat transfer rate information. The output from the infrared thermometer and calorimeter is then fed into an analog-to-digital converter which provides digitized data to a computer. This computer then calculates combined thermophysical properties and a teleprinter prints out all the data. Thus, results are available within 7 minutes of test initiation as opposed to the weeks or months required using prior techniques.

  3. Comparative investigation of multiplane thrust vectoring nozzles

    NASA Technical Reports Server (NTRS)

    Capone, F.; Smereczniak, P.; Spetnagel, D.; Thayer, E.

    1992-01-01

    The inflight aerodynamic performance of multiplane vectoring nozzles is critical to development of advanced aircraft and flight control systems utilizing thrust vectoring. To investigate vectoring nozzle performance, subscale models of two second-generation thrust vectoring nozzle concepts currently under development for advanced fighters were integrated into an axisymmetric test pod. Installed drag and vectoring performance characteristics of both concepts were experimentally determined in wind tunnel testing. CFD analyses were conducted to understand the impact of internal flow turning on thrust vectoring characteristics. Both nozzles exhibited drag comparable with current nonvectoring axisymmetric nozzles. During vectored-thrust operations, forces produced by external flow effects amounted to about 25 percent of the total force measured.

  4. Tomato Infection by Whitefly-Transmitted Circulative and Non-Circulative Viruses Induce Contrasting Changes in Plant Volatiles and Vector Behaviour.

    PubMed

    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

  5. 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

  6. 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.

  7. 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. PMID:24353452

  8. 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

  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. Potential Effects of Climate Change on Ecological Interaction Outcomes Between Two Disease-Vector Mosquitoes: A Mesocosm Experimental Study.

    PubMed

    Leonel, B F; Koroiva, R; Hamada, N; Ferreira-Keppler, R L; Roque, F O

    2015-09-01

    The objective of this study was to experimentally assess the effects of different climate change scenarios on the outcomes of interactions between Aedes aegypti (L.) and Culex quinquefasciatus (Say) (Diptera: Culicidae) larvae. The experimental design maintained a constant density of specimens while the proportion of the species in different experimental climate change scenarios varied. Our results indicate that survival of the two species was not affected, but larval development and pupation times decreased under elevated atmospheric CO(2) concentration and high air temperature. In climate change scenarios with both species together, the survival of Ae. aegypti increased and its larval development time decreased with increasing density of Cx. quinquefasciatus. This may be attributed to the effects of intraspecific competition being more significant than interspecific competition in Ae. aegypti. Our study also reveals that climatic changes may affect the patterns of interactions between Cx. quinquefasciatus and Ae. aegypti. Alterations in climatic conditions changed the response of context-dependent competition, indicating the importance of studies on how ecological interactions will be affected by projected future climatic change. PMID:26336208

  11. Method for determining thermo-physical properties of specimens. [photographic recording of changes in thin film phase-change temperature indicating material in wind tunnel

    NASA Technical Reports Server (NTRS)

    Jones, R. A. (Inventor)

    1974-01-01

    The square root of the product of thermophysical properties q, c and k, where p is density, c is specific heat and k is thermal conductivity, is determined directly on a test specimen such as a wind tunnel model. The test specimen and a reference specimen of known specific heat are positioned at a given distance from a heat source. The specimens are provided with a coating, such as a phase change coating, to visually indicate that a given temperature was reached. A shutter interposed between the heat source and the specimens is opened and a motion picture camera is actuated to provide a time record of the heating step. The temperature of the reference specimen is recorded as a function of time. The heat rate to which both the test and reference specimens were subjected is determined from the temperature time response of the reference specimen by the conventional thin-skin calorimeter equation.

  12. 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.

  13. 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

  14. Wind-driven nutrient pulses to the subsurface chlorophyll maximum in seasonally stratified shelf seas

    NASA Astrophysics Data System (ADS)

    Williams, Charlotte; Sharples, Jonathan; Mahaffey, Claire; Rippeth, Tom

    2013-10-01

    seas are an important global carbon sink. In the seasonal thermocline, the subsurface chlorophyll maximum (SCM) supports almost half of summer shelf production. Using observations from the seasonally stratified Celtic Sea (June 2010), we identify wind-driven inertial oscillations as a mechanism for supplying the SCM with the nitrate needed for phytoplankton growth and carbon fixation. Analysis of wind, currents, and turbulent dissipation indicates that inertial oscillations are triggered by a change in the wind velocity. High magnitude, short-lived dissipation spikes occur when the shear and wind vectors align, increasing the daily nitrate flux to the SCM by a factor of at least 17. However, it is likely that the sampling resolution of turbulent dissipation does not always capture the maximum wind-driven peak in mixing. We estimate that wind-driven inertial oscillations supply the SCM with ~33% to 71% of the nitrate required for new production in shelf seas during summer.

  15. Implications of global change and climate variability for vector-borne diseases: generic approaches to impact assessments.

    PubMed

    Sutherst, R W

    1998-06-01

    Global change is pervasive and occurring at a dramatic rate. It involves changes in land use, vegetation cover, species translocations and even the climate of the planet. The consequences for the biosphere are uncertain. Past research emphasis has been on the science of climate change as the major driver of policy. The present priority in the global-change community is to define the likely nature and extent of those impacts on biodiversity and the functioning of ecosystems. In addition, increasing consideration is now being given to adaptation measures. The way in which that is being initiated is to develop adaptation measures to respond to medium-term climate variability in the form of altered El Nino and similar cycles, and changes in the frequency of extreme events. Given the large number of stakeholders in agriculture, human health and environment, there is a need for great efficiencies if the scientific community is going to be able to respond in a meaningful way with foreseeable resources. The plethora of problems means that generic approaches are needed. The present situation, with parasitologists each doing their own thing in terms of developing and using software tools, is like the tower of Babel. Parasitologists need common tools and languages to facilitate communication and collaboration. Advances in computing, with object-oriented programming languages and seamless exchange of information between different packages and platforms, are providing some exciting opportunities to overcome these problems. PMID:9673872

  16. 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.

  17. 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…

  18. 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…

  19. 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…

  20. 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…

  1. Winds of Change in New York City's Public Schools: Can Chancellor Macchiarola Set a New Course?

    ERIC Educational Resources Information Center

    Seeley, David S.

    1979-01-01

    Many New Yorkers have given up on the public schools and on the chance for reform. However, the school system's new chancellor, Frank Macchiarola, seems to have both the necessary commitment to change and the administrative skills. Interim evaluations have been made of his performance, with the following results: (1) Staff Performance--good work…

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. How do cosmic rays change their energy in the solar wind?

    NASA Technical Reports Server (NTRS)

    Jones, F. C.

    1983-01-01

    The diffusion-convection (modulation) equation is derived directly from the Boltzmann equation on the basis of a minimum number of assumptions concerning the scattering process, among which are: (1) that the scattered particles undergo no energy change, and (2) that isotropy is an equilibrium state. It is noted that, in the event that the background plasma contains a magnetic field and the flow speeds of the plasma and scattering centers are different, additional terms arise that will modify the equations. If, moreover, the scatterers have individual motions relative to their average flow, the second-order Fermi acceleration term will appear.

  7. Aerodynamics of thrust vectoring

    NASA Technical Reports Server (NTRS)

    Tseng, J. B.; Lan, C. Edward

    1989-01-01

    Thrust vectoring as a means to enhance maneuverability and aerodynamic performane of a tactical aircraft is discussed. This concept usually involves the installation of a multifunction nozzle. With the nozzle, the engine thrust can be changed in direction without changing the attitude of the aircraft. Change in the direction of thrust induces a significant change in the aerodynamic forces on the aircraft. Therefore, this device can be used for lift-augmenting as well as stability and control purposes. When the thrust is deflected in the longitudinal direction, the lift force and the pitching stability can be manipulated, while the yawing stability can be controlled by directing the thrust in the lateral direction.

  8. 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%. PMID:26979381

  9. 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. PMID:21536905

  10. 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

  11. 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

  12. Vector-borne diseases.

    PubMed

    Gubler, D J

    2009-08-01

    Vector-borne diseases have been the scourge of man and animals since the beginning of time. Historically, these are the diseases that caused the great plagues such as the 'Black Death' in Europe in the 14th Century and the epidemics of yellow fever that plagued the development of the New World. Others, such as Nagana, contributed to the lack of development in Africa for many years. At the turn of the 20th Century, vector-borne diseases were among the most serious public and animal health problems in the world. For the most part, these diseases were controlled by the middle of the 20th Century through the application of knowledge about their natural history along with the judicious use of DDT (dichlorodiphenyltrichloroethane) and other residual insecticides to interrupt the transmission cycle between arthropod and vertebrate host. However, this success initiated a period of complacency in the 1960s and 1970s, which resulted in the redirection of resources away from prevention and control of vector-borne diseases. The 1970s was also a time in which there were major changes to public health policy. Global trends, combined with changes in animal husbandry, urbanisation, modern transportation and globalisation, have resulted in a global re-emergence of epidemic vector-borne diseases affecting both humans and animals over the past 30 years. PMID:20128467

  13. 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.

  14. Winds of change: growing demands for transparency in the relationship between doctors and the pharmaceutical industry.

    PubMed

    Mitchell, Philip B

    2009-09-01

    The relationship between medicine and the pharmaceutical industry in the United States is undergoing rapid and momentous change; US Senator Grassley has alleged inadequate disclosure of earnings from industry and lack of acknowledgement of conflicts of interest by leading academics. This article is based on the premise that it is not the relationship per se that is the problem, but rather how that relationship is enacted. The influential 2008 report of the Association of American Medical Colleges (AAMC) has provided detailed recommendations on appropriate interactions between academic physicians and industry (eg, proscribing receipt of gifts including travel support, and proscribing speaking at industry-sponsored educational programs). Contrary to expectations, there has been widespread acceptance of such guidelines. In Australia, details of all industry-sponsored educational events are now listed on the Medicines Australia website. Australian doctors have no alternative but to drastically improve the transparency of their interactions with industry, both in terms of the remuneration received and disclosure of potential conflicts of interest. Australian universities should seriously consider developing recommendations similar to those of the AAMC. PMID:19740050

  15. 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. PMID:27461425

  16. 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.

  17. 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.

  18. 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. PMID:24372751

  19. The effect of changing solar wind conditions on the inner magnetosphere and ring current: A model data comparison

    NASA Astrophysics Data System (ADS)

    Patra, S.; Spencer, E.

    2015-08-01

    We investigate the rate at which the open drift paths in the near-Earth magnetosphere convert to closed paths during events with a sudden northward turning of the interplanetary magnetic field (IMF Bz) after the peak of a geomagnetic storm. The geomagnetic storm on 17 August 2001 with an abrupt turning of the IMF Bz after the peak in SYM-H index is chosen in this study. The Block-Adaptive-Tree Solar-Wind Roe-Type Upwind Scheme model along with the Fok Ring Current (FRC) model available at Community Coordinated Modeling Center is used to model this event. The unique movie maps of the worldwide magnetometer stations are used to compare with the numerical results. The results indicate that ground magnetic disturbance remains asymmetric for some time after the start of the recovery phase even for a storm with abrupt northward turning of the IMF Bz. FRC simulation results suggest that the flow-out losses decrease under weakened magnetospheric convection but at a rate slower than the change in IMF Bz. These results indicate that the flow-out losses rapidly become smaller as the IMF Bz turns northward during the early recovery phase of a storm and the contribution of the tail current to the SYM-H index is important.

  20. 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.

  1. 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. PMID:24132939

  2. 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

  3. 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

  4. 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.

  5. Downscaling and predictability of historical monthly mean surface winds over a region of complex terrain and marine influence: Western Canada

    NASA Astrophysics Data System (ADS)

    Curry, C.; van der Kamp, D.; Monahan, A. H.

    2010-12-01

    valleys and ocean channels. Predictability at stations in regions of relatively flat terrain was less dependent on wind direction. The latter stations also displayed region-wide seasonal shifts in the direction of the most skillfully predicted wind component. In summary, at most stations in Western Canada, monthly mean vector wind components were more reliably predicted than wind speeds. This result complicates the assessment of local changes in mean wind speed, extremes, and wind energy under climate change that is often a desired outcome of the downscaling exercise using modelled fields as predictors. However, useful projections might still be obtained at stations where a single wind direction is dominant.

  6. 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.

  7. 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.

  8. Amazonian malaria: Asymptomatic human reservoirs, diagnostic challenges, environmentally-driven changes in mosquito vector populations, and the mandate for sustainable control strategies

    PubMed Central

    da Silva-Nunes, Mônica; Moreno, Marta; Conn, Jan E.; Gamboa, Dionicia; Abeles, Shira; Vinetz, Joseph M.; Ferreira, Marcelo U.

    2012-01-01

    Across the Americas and the Caribbean, nearly 561,000 slide-confirmed malaria infections were reported officially in 2008. The nine Amazonian countries accounted for 89% of these infections; Brazil and Peru alone contributed 56% and 7% of them, respectively. Local populations of the relatively neglected parasite P. vivax, which currently accounts for 77% of the regional malaria burden, are extremely diverse genetically and geographically structured. At a time when malaria elimination is placed on the public health agenda of several endemic countries, it remains unclear why malaria proved so difficult to control in areas of relatively low levels of transmission such as the Amazon Basin. We hypothesize that asymptomatic parasite carriage and massive environmental changes that affect vector abundance and behavior are major contributors to malaria transmission in epidemiologically diverse areas across the Amazon Basin. Here we review available data supporting this hypothesis and discuss their implications for current and future malaria intervention policies in the region. Given that locally generated scientific evidence is urgently required to support malaria control interventions in Amazonia, we briefly describe the aims of our current field-oriented malaria research in rural villages and gold-mining enclaves in Peru and a recently opened agricultural settlement in Brazil. PMID:22015425

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Operational cloud-motion winds from Meteosat infrared images

    SciTech Connect

    Schmetz, J.; Holmlund, K.; Mason, B.; Gaertner, V.; Koch, A.; Van De Berg, L. ); Hoffman, J. ); Strauss, B. )

    1993-07-01

    The displacements 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 images (10.5-12.5 [mu]m) of the European geostationary Meteosat 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 [mu]m) channel. Cloud-motion winds are subject to various quality checks that include manual quality controls 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 Meteosat winds. The slow speed bias of high-level CMWs (<400 hPa) in comparison to radiosonde winds has been reduced from about 4 to 1.3 m s[sup [minus]1] for a mean wind speed of 24 m s[sup [minus]1]. Correspondingly, the rms vector error of Meteosat high-level CMWs decreased from about 7.8 to 5 m s[sup [minus]1]. Medium-and low-level CMWs were also significantly improved. 56 refs., 12 figs., 2 tabs.

  17. 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.

  18. 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. PMID:25537120

  19. 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

  20. Wind Simulation

    Energy Science and Technology Software Center (ESTSC)

    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.

  1. 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

  2. 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...

  3. 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.

  4. 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

  5. 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

  6. 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

    2016-03-01

    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

  7. 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.

  8. 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…

  9. Validation Campaigns for Sea Surface Wind and Wind Profile by Ground-Based Doppler Wind Lidar

    NASA Astrophysics Data System (ADS)

    Liu, Zhishen; Wu, Songhua; Song, Xiaoquan; Liu, Bingyi; Li, Zhigang

    2010-12-01

    According to the research frame of ESA-MOST DRAGON Cooperation Program (ID5291), Chinese partners from Ocean Remote Sensing Institute of Ocean University of China have carried out a serial of campaigns for ground-based lidar validations and atmospheric observations. ORSI/OUC Doppler wind lidar has been developed and deployed to accurately measure wind speed and direction over large areas in real time -- an application useful for ADM-Aeolus VAL/CAL, aviation safety, weather forecasting and sports. The sea surface wind campaigns were successfully accomplished at the Qingdao sailing competitions during the 29th Olympic Games. The lidar located at the seashore near the sailing field, and made a horizontal scan over the sea surface, making the wind measurement in real time and then uploading the data to the local meteorological station every 10 minutes. In addition to the sea surface wind campaigns, ORSI/OUC Doppler wind lidar was deployed on the wind profile observations for the China's Shenzhou 7 spacecraft landing zone weather campaigns in September 2008 in Inner Mongolia steppe. Wind profile was tracked by the mobile Doppler lidar system to help to predict the module's landing site. During above ground tests, validation lidar is tested to be able to provide an independent and credible measurement of radial wind speed, wind profile, 3D wind vector, aerosol- backscattering ratio, aerosol extinction coefficient, extinction-to-backscatter ratio in the atmospheric boundary layer and troposphere, sea surface wind vectors, which will be an independent and very effective validation tool for upcoming ADM-Aeolus project.

  10. Summertime wind climate in Yerevan: valley wind systems

    NASA Astrophysics Data System (ADS)

    Gevorgyan, Artur

    2016-05-01

    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.

  11. Foamy virus vectors.

    PubMed Central

    Russell, D W; Miller, A D

    1996-01-01

    Human foamy virus (HFV) is a retrovirus of the spumavirus family. We have constructed vectors based on HFV that encode neomycin phosphotransferase and alkaline phosphatase. These vectors are able to transduce a wide variety of vertebrate cells by integration of the vector genome. Unlike vectors based on murine leukemia virus, HFV vectors are not inactivated by human serum, and they transduce stationary-phase cultures more efficiently than murine leukemia virus vectors. These properties, as well as their large packaging capacity, make HFV vectors promising gene transfer vehicles. PMID:8523528

  12. 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

  13. Distribution of AAV8 particles in cell lysates and culture media changes with time and is dependent on the recombinant vector.

    PubMed

    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

  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. Emerging Vector-Borne Diseases - Incidence through Vectors.

    PubMed

    Savić, Sara; Vidić, Branka; Grgić, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

    2014-01-01

    Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests - ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples

  16. 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...

  17. 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 ...

  18. Trends and abrupt changes in 104 years of ice cover and water temperature in a dimictic lake in response to air temperature, wind speed, and water clarity drivers

    NASA Astrophysics Data System (ADS)

    Magee, Madeline R.; Wu, Chin H.; Robertson, Dale M.; Lathrop, Richard C.; Hamilton, David P.

    2016-05-01

    The one-dimensional hydrodynamic ice model, DYRESM-WQ-I, was modified to simulate ice cover and thermal structure of dimictic Lake Mendota, Wisconsin, USA, over a continuous 104-year period (1911-2014). The model results were then used to examine the drivers of changes in ice cover and water temperature, focusing on the responses to shifts in air temperature, wind speed, and water clarity at multiyear timescales. Observations of the drivers include a change in the trend of warming air temperatures from 0.081 °C per decade before 1981 to 0.334 °C per decade thereafter, as well as a shift in mean wind speed from 4.44 m s-1 before 1994 to 3.74 m s-1 thereafter. Observations show that Lake Mendota has experienced significant changes in ice cover: later ice-on date(9.0 days later per century), earlier ice-off date (12.3 days per century), decreasing ice cover duration (21.3 days per century), while model simulations indicate a change in maximum ice thickness (12.7 cm decrease per century). Model simulations also show changes in the lake thermal regime of earlier stratification onset (12.3 days per century), later fall turnover (14.6 days per century), longer stratification duration (26.8 days per century), and decreasing summer hypolimnetic temperatures (-1.4 °C per century). Correlation analysis of lake variables and driving variables revealed ice cover variables, stratification onset, epilimnetic temperature, and hypolimnetic temperature were most closely correlated with air temperature, whereas freeze-over water temperature, hypolimnetic heating, and fall turnover date were more closely correlated with wind speed. Each lake variable (i.e., ice-on and ice-off dates, ice cover duration, maximum ice thickness, freeze-over water temperature, stratification onset, fall turnover date, stratification duration, epilimnion temperature, hypolimnion temperature, and hypolimnetic heating) was averaged for the three periods (1911-1980, 1981-1993, and 1994-2014) delineated by

  19. 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. PMID:27321878

  20. 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. PMID:25806896

  1. Multi-locus phylogeography of the dusky dolphin (Lagenorhynchus obscurus): passive dispersal via the west-wind drift or response to prey species and climate change?

    PubMed Central

    Harlin-Cognato, April D; Markowitz, Tim; Würsig, Bernd; Honeycutt, Rodney L

    2007-01-01

    Background The dusky dolphin (Lagenorhynchus obscurus) is distributed along temperate, coastal regions of New Zealand, South Africa, Argentina, and Peru where it feeds on schooling anchovy, sardines, and other small fishes and squid tightly associated with temperate ocean sea surface temperatures. Previous studies have suggested that the dusky dolphin dispersed in the Southern Hemisphere eastward from Peru via a linear, temperate dispersal corridor provided by the circumpolar west-wind drift. With new mitochondrial and nuclear DNA sequence data, we propose an alternative phylogeographic history for the dusky dolphin that was structured by paleoceanographic conditions that repeatedly altered the distribution of its temperate prey species during the Plio-Pleistocene. Results In contrast to the west-wind drift hypothesis, phylogenetic analyses support a Pacific/Indian Ocean origin, with a relatively early and continued isolation of Peru from other regions. Dispersal of the dusky dolphin into the Atlantic is correlated with the history of anchovy populations, including multiple migrations from New Zealand to South Africa. Additionally, the cooling of the Eastern Equatorial Pacific led to the divergence of anchovy populations, which in turn explains the north-south equatorial transgression of L. obliquidens and the subsequent divergence of L. obscurus in the Southern Hemisphere. Conclusion Overall, our study fails to support the west-wind drift hypothesis. Instead, our data indicate that changes in primary productivity and related abundance of prey played a key role in shaping the phylogeography of the dusky dolphin, with periods of ocean change coincident with important events in the history of this temperate dolphin species. Moderate, short-term changes in sea surface temperatures and current systems have a powerful effect on anchovy populations; thus, it is not infeasible that repeated fluctuations in anchovy populations continue to play an important role in the

  2. 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.

  3. 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

  4. Virus-Mediated Chemical Changes in Rice Plants Impact the Relationship between Non-Vector Planthopper Nilaparvata lugens Stål and Its Egg Parasitoid Anagrus nilaparvatae Pang et Wang

    PubMed Central

    Gao, Guanchun; Zhou, Xiaojun; Zheng, Xusong; Sun, Yujian; Yang, Yajun; Tian, Junce; Lu, Zhongxian

    2014-01-01

    In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae. PMID:25141278

  5. 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.

  6. 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. PMID:26918465

  7. 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

  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. 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. PMID:21212205

  10. Reduced Vector Preisach Model

    NASA Technical Reports Server (NTRS)

    Patel, Umesh D.; Torre, Edward Della; Day, John H. (Technical Monitor)

    2002-01-01

    A new vector Preisach model, called the Reduced Vector Preisach model (RVPM), was developed for fast computations. This model, derived from the Simplified Vector Preisach model (SVPM), has individual components that like the SVPM are calculated independently using coupled selection rules for the state vector computation. However, the RVPM does not require the rotational correction. Therefore, it provides a practical alternative for computing the magnetic susceptibility using a differential approach. A vector version, using the framework of the DOK model, is implemented. Simulation results for the reduced vector Preisach model are also presented.

  11. Transcriptomics and disease vector control

    PubMed Central

    2010-01-01

    Next-generation sequencing can be used to compare transcriptomes under different conditions. A study in BMC Genomics applies this approach to investigating the effects of exposure to a range of xenobiotics on changes in gene expression in the larvae of Aedes aegypti, the mosquito vector of dengue fever. See research article http://www.biomedcentral.com/1471-2164/11/216 PMID:20525113

  12. Sources of uncertainty in projections of twenty-first century westerly wind changes over the Amundsen Sea, West Antarctica, in CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Bracegirdle, Thomas J.; Turner, John; Hosking, J. Scott; Phillips, Tony

    2014-10-01

    The influence of changes in winds over the Amundsen Sea has been shown to be a potentially key mechanism in explaining rapid loss of ice from major glaciers in West Antarctica, which is having a significant impact on global sea level. Here, Coupled Model Intercomparison Project Phase 5 (CMIP5) climate model data are used to assess twenty-first century projections in westerly winds over the Amundsen Sea ( U AS ). The importance of model uncertainty and internal climate variability in RCP4.5 and RCP8.5 scenario projections are quantified and potential sources of model uncertainty are considered. For the decade 2090-2099 the CMIP5 models show an ensemble mean twenty-first century response in annual mean U AS of 0.3 and 0.7 m s-1 following the RCP4.5 and RCP8.5 scenarios respectively. However, as a consequence of large internal climate variability over the Amundsen Sea, it takes until around 2030 (2065) for the RCP8.5 response to exceed one (two) standard deviation(s) of decadal internal variability. In all scenarios and seasons the model uncertainty is large. However the present-day climatological zonal wind bias over the whole South Pacific, which is important for tropical teleconnections, is strongly related to inter-model differences in projected change in U AS (more skilful models show larger U AS increases). This relationship is significant in winter (r = -0.56) and spring (r = -0.65), when the influence of the tropics on the Amundsen Sea region is known to be important. Horizontal grid spacing and present day sea ice extent are not significant sources of inter-model spread.

  13. Generation of Large-Scale Winds in Horizontally Anisotropic Convection.

    PubMed

    von Hardenberg, J; Goluskin, D; Provenzale, A; Spiegel, E A

    2015-09-25

    We simulate three-dimensional, horizontally periodic Rayleigh-Bénard convection, confined between free-slip horizontal plates and rotating about a distant horizontal axis. When both the temperature difference between the plates and the rotation rate are sufficiently large, a strong horizontal wind is generated that is perpendicular to both the rotation vector and the gravity vector. The wind is turbulent, large-scale, and vertically sheared. Horizontal anisotropy, engendered here by rotation, appears necessary for such wind generation. Most of the kinetic energy of the flow resides in the wind, and the vertical turbulent heat flux is much lower on average than when there is no wind. PMID:26451558

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Understanding Singular Vectors

    ERIC Educational Resources Information Center

    James, David; Botteron, Cynthia

    2013-01-01

    matrix yields a surprisingly simple, heuristical approximation to its singular vectors. There are correspondingly good approximations to the singular values. Such rules of thumb provide an intuitive interpretation of the singular vectors that helps explain why the SVD is so…

  19. The vector ruling protractor

    NASA Technical Reports Server (NTRS)

    Zahm, A F

    1924-01-01

    The theory, structure and working of a vector slide rule is presented in this report. This instrument is used for determining a vector in magnitude and position when given its components and its moment about a point in their plane.

  20. 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

  1. Restart 68000 vector remapping

    SciTech Connect

    Gustin, J.

    1984-05-03

    The circuit described allows power-on-reset (POR) vector fetch from ROM for a 68000 microprocessor. It offers programmability of exception vectors, including the restart vector. This method eliminates the need for high-resolution, address-decoder peripheral circuitry.

  2. Rhotrix Vector Spaces

    ERIC Educational Resources Information Center

    Aminu, Abdulhadi

    2010-01-01

    By rhotrix we understand an object that lies in some way between (n x n)-dimensional matrices and (2n - 1) x (2n - 1)-dimensional matrices. Representation of vectors in rhotrices is different from the representation of vectors in matrices. A number of vector spaces in matrices and their properties are known. On the other hand, little seems to be…

  3. MATRIX AND VECTOR SERVICES

    Energy Science and Technology Software Center (ESTSC)

    2001-10-18

    PETRA V2 provides matrix and vector services and the ability construct, query, and use matrix and vector objects that are used and computed by TRILINOS solvers. It provides all basic matr5ix and vector operations for solvers in TRILINOS.

  4. Insulated Foamy Viral Vectors.

    PubMed

    Browning, Diana L; Collins, Casey P; Hocum, Jonah D; Leap, David J; Rae, Dustin T; Trobridge, Grant D

    2016-03-01

    Retroviral vector-mediated gene therapy is promising, but genotoxicity has limited its use in the clinic. Genotoxicity is highly dependent on the retroviral vector used, and foamy viral (FV) vectors appear relatively safe. However, internal promoters may still potentially activate nearby genes. We developed insulated FV vectors, using four previously described insulators: a version of the well-studied chicken hypersensitivity site 4 insulator (650cHS4), two synthetic CCCTC-binding factor (CTCF)-based insulators, and an insulator based on the CCAAT box-binding transcription factor/nuclear factor I (7xCTF/NF1). We directly compared these insulators for enhancer-blocking activity, effect on FV vector titer, and fidelity of transfer to both proviral long terminal repeats. The synthetic CTCF-based insulators had the strongest insulating activity, but reduced titers significantly. The 7xCTF/NF1 insulator did not reduce titers but had weak insulating activity. The 650cHS4-insulated FV vector was identified as the overall most promising vector. Uninsulated and 650cHS4-insulated FV vectors were both significantly less genotoxic than gammaretroviral vectors. Integration sites were evaluated in cord blood CD34(+) cells and the 650cHS4-insulated FV vector had fewer hotspots compared with an uninsulated FV vector. These data suggest that insulated FV vectors are promising for hematopoietic stem cell gene therapy. PMID:26715244

  5. Orbital period changes and possible stellar wind mass loss in the algol-type binary system AT Pegasi

    NASA Astrophysics Data System (ADS)

    Hanna, Magdy A.

    2012-12-01

    An analysis of the measurements of mid-eclipse times of AT Peg has been presented. It indicates a period decrease rate of dP/dt = -4.2 × 10-7 d/yr, which can be interpreted in terms of mass loss from the system via stellar wind with a rate between (1 and 2) × 10-8 Mʘ/yr. The O-C diagram shows a growing sine wave covering two different cycles of 13 yr and 31.9 yr with amplitudes equal to 0.026 and 0.032 day, respectively. These unequal durations of the cycles may be explained by magnetic activity cycling variations due to star spots. The obtained characteristics of the second cycle are consistent with similar systems when applying Applegate’s mechanism.

  6. 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.

  7. Saturn’s Zonal Winds at Cloud Level between 2004-2013 from Cassini ISS Images

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    We examine images of Saturn returned by Cassini orbiter’s Imaging Science Subsystem (ISS) camera between 2004 to 2013 to analyze the temporal evolution of the zonal mean wind speed as a function of latitude. Our study primarily examines the images captured in the 752-nm continuum band using the CB2 filter. Images captured using the CB2 filter sense the upper troposphere of Saturn between 350 mbar and 500 mbar (Pérez-Hoyos and Sánchez-Lavega, 2006; Sánchez-Lavega et al, 2006; García-Melendo et al, 2009). We measure the wind speed using a two-dimensional Correlation Imaging Velocimetry (CIV) technique. The wind vectors are computed using pairs of images separated in time by up to two planetary rotations, and binned in latitude to determine the zonal mean wind profile, which typically covers a limited range of latitude. To achieve pole-to-pole coverage, we systematically merge all the wind measurements during each of the calendar years in order to compile a yearly, near-global record of Saturn's zonal wind structure. Using our wind measurements, we analyze the temporal evolution of the zonal wind. We specifically focus on changes in the wind profile after the 2009 equinox; we predict that changes in the insolation pattern caused by the shifting ring shadows affect the horizontal temperature gradient, and change the zonal mean wind through the thermal wind relationship. Furthermore, we also extend the zonal wind analysis by Sayanagi et al (2013), who detected changes in the zonal wind related to the Great Storm of 2010-2011, to study the subsequent evolution of the region affected by the storm. We compare our results with previously published zonal wind profiles obtained from Voyager 1 and 2 (Sánchez-Lavega et al, 2000) and Cassini (García-Melendo et al, 2011). Out study is supported by the Cassini Project, and our investigation is funded by NASA Outer Planets Research Program grant NNX12AR38G and NSF Astronomy and Astrophysics grant 1212216 to KMS.

  8. 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.

  9. Response of dominant wind wave fields to abrupt wind increase

    NASA Astrophysics Data System (ADS)

    Caulliez, Guillemette

    2013-04-01

    Over the last decades, significant progress has been made in modelling wave field development by wind observed at sea, based on more elaborated numerical schemes and refined parametrizations of wind energy input and wave dissipation. In such models, the wind wave growth in space or time is generally governed by the average wind speed evaluated at one reference level and the natural wind speed variability is neglected. However, the impact of this assumption is not really known, mainly because of the lack of appropriate observations. To revisit this question, we report a detailed laboratory investigation aimed at describing the dominant wave field evolution resulting from an abrupt local wind speed increase. The experiments were conducted in the large Marseille-Luminy wind wave tank for moderate to high wind conditions. At 23 m fetch, a contraction of the wind tunnel section by a convergent profile created a spatial wind speed acceleration over a distance of about 2 m. Downwind, the wind speed, enhanced by a factor 1.4, was kept constant up to the end of the water tank. The wind wave field development induced by such a "wind gust" was investigated at successive fetches by wave probes and compared to those observed at similar fetches for homogeneous wind conditions. When wind increases, these observations first revealed no dramatic change in the evolution of the dominant spectral peak with fetch. The dominant wave energy which increases slowly for constant wind conditions, follows the wind speed but with a significant space lag. For well-established gravity wave fields, the space relaxation scales which describe this evolution do not depend noticeably on wind, all the curves collapse into a single one when wave quantities are normalized by their value observed just upstream the convergent profile. The wave growth rate observed for the new equilibrium state can be described by the Hasselman et al. (1973) relationship but with an "equivalent'' shorter fetch since, in

  10. 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.

  11. 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.

  12. Covariantized vector Galileons

    NASA Astrophysics Data System (ADS)

    Hull, Matthew; Koyama, Kazuya; Tasinato, Gianmassimo

    2016-03-01

    Vector Galileons are ghost-free systems containing higher derivative interactions of vector fields. They break the vector gauge symmetry, and the dynamics of the longitudinal vector polarizations acquire a Galileon symmetry in an appropriate decoupling limit in Minkowski space. Using an Arnowitt-Deser-Misner approach, we carefully reconsider the coupling with gravity of vector Galileons, with the aim of studying the necessary conditions to avoid the propagation of ghosts. We develop arguments that put on a more solid footing the results previously obtained in the literature. Moreover, working in analogy with the scalar counterpart, we find indications for the existence of a "beyond Horndeski" theory involving vector degrees of freedom that avoids the propagation of ghosts thanks to secondary constraints. In addition, we analyze a Higgs mechanism for generating vector Galileons through spontaneous symmetry breaking, and we present its consistent covariantization.

  13. Numerical Calculations of Wind Flow in a Full-Scale Wind Test Facility

    SciTech Connect

    Oh, Chang H; Lacey, Jerry Mark

    1999-06-01

    Numerical studies on wind flow around the Texas Tech University (TTU) Wind Engineering Research Field Laboratory (WERFL) building were conducted. The main focus of this paper is wind loads on the TTU building in the INEEL proposed Windstorm Simulation Center. The results are presented in the form of distributions of static pressure, dynamic pressure, pressure coefficients, and velocity vectors on the surface and the vicinity of the TTU building.

  14. Numerical calculations of wind flow in a full-scale wind test facility

    SciTech Connect

    C.H. Oh; J.M. Lacey

    1999-06-20

    Numerical studies on wind flow around the Texas Tech University (TTU) Wind Engineering Research Field Laboratory (WERFL) building were conducted. The main focus of this paper is wind loads on the TTU building in the INEEL proposed Windstorm Simulation Center. The results are presented in the form of distributions of static pressure, dynamic pressure, pressure coefficients, and velocity vectors on the surface and the vicinity of the TTU building.

  15. Optical observations of thermospheric neutral winds at Arecibo between 1980 and 1987

    SciTech Connect

    Burnside, R.G.; Tepley, C.A. )

    1989-03-01

    Since 1980, optical observations of nighttime thermospheric winds have been made using a Fabry-Perot interferometer at the Arecibo Observatory, Puerto Rico. High-resolution spectra of the O({sup 1}D) airglow emission at 630.0 nm are obtained by observing at eight equally spaced azimuth positions and a fixed zenith angle of 60{degree}. The neutral wind field is inferred by assuming that each component of the wind velocity vector may be expanded in a linear Taylor expansion about a point directly above the observatory. Both the zonal and meridional components of the thermospheric wind field are observed to have well-defined seasonal and nocturnal variations. For each year between 1980 and 1987, eastward flow was observed in the evening hours, with an average peak velocity of about 100 m s{sup {minus}1} near 2,200 AST. In the winter months, the zonal wind generally remains eastward throughout the night. However, in summer, a reversal to westward flow is usually observed after local midnight. In the meridional direction, the largest equatorward velocities are observed in summer. A reduction (or reversal) in the meridional wind velocity is most often observed after midnight in the summer and equinoctial months. The authors find that the nocturnal and seasonal variations in the neutral wind field at Arecibo are remarkably unaffected by changes in the solar cycle.

  16. 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.

  17. Forecasting Caspian Sea level changes using satellite altimetry data (June 1992-December 2013) based on evolutionary support vector regression algorithms and gene expression programming

    NASA Astrophysics Data System (ADS)

    Imani, Mo