Science.gov

Sample records for airborne gravity surveys

  1. The alpine Swiss-French airborne gravity survey

    NASA Astrophysics Data System (ADS)

    Verdun, Jérôme; Klingelé, Emile E.; Bayer, Roger; Cocard, Marc; Geiger, Alain; Kahle, Hans-Gert

    2003-01-01

    In February 1998, a regional-scale, airborne gravity survey was carried out over the French Occidental Alps within the framework of the GéoFrance 3-D research program.The survey consisted of 18 NS and 16 EW oriented lines with a spacing of 10 and 20 km respectively, covering the whole of the Western French Alps (total area: 50 000 km2; total distance of lines flown: 10 000 km). The equipment was mounted in a medium-size aircraft (DeHavilland Twin Otter) flowing at a constant altitude of 5100 m a.s.l, and at a mean ground speed of about 280 km h-1. Gravity was measured using a LaCoste & Romberg relative, air/sea gravimeter (type SA) mounted on a laser gyro stabilized platform. Data from 5 GPS antennae located on fuselage and wings and 7 ground-based GPS reference stations were used to determine position and aircraft induced accelerations.The gravimeter passband was derived by comparing the vertical accelerations provided by the gravimeter with those estimated from the GPS positions. This comparison showed that the gravimeter is not sensitive to very short wavelength aircraft accelerations, and therefore a simplified formulation for computing airborne gravity measurements was developed. The intermediate and short wavelength, non-gravitational accelerations were eliminated by means of digital, exponential low-pass filters (cut-off wavelength: 16 km). An important issue in airborne gravimetry is the reliability of the airborne gravity surveys when compared to ground surveys. In our studied area, the differences between the airborne-acquired Bouguer anomaly and the ground upward-continued Bouguer anomaly of the Alps shows a good agreement: the rms of these differences is equal to 7.68 mGal for a spatial resolution of 8 km. However, in some areas with rugged topography, the amplitudes of those differences have a striking correlation with the topography. We then argue that the choice of an appropriate density (reduction by a factor of 10 per cent) for computing the

  2. Digital data from the Great Sand Dunes airborne gravity gradient survey, south-central Colorado

    USGS Publications Warehouse

    Drenth, B.J.; Abraham, J.D.; Grauch, V.J.S.; Labson, V.F.; Hodges, G.

    2013-01-01

    This report contains digital data and supporting explanatory files describing data types, data formats, and survey procedures for a high-resolution airborne gravity gradient (AGG) survey at Great Sand Dunes National Park, Alamosa and Saguache Counties, south-central Colorado. In the San Luis Valley, the Great Sand Dunes survey covers a large part of Great Sand Dunes National Park and Preserve. The data described were collected from a high-resolution AGG survey flown in February 2012, by Fugro Airborne Surveys Corp., on contract to the U.S. Geological Survey. Scientific objectives of the AGG survey are to investigate the subsurface structural framework that may influence groundwater hydrology and seismic hazards, and to investigate AGG methods and resolution using different flight specifications. Funding was provided by an airborne geophysics training program of the U.S. Department of Defense's Task Force for Business & Stability Operations.

  3. Error analysis of a new planar electrostatic gravity gradiometer for airborne surveys

    NASA Astrophysics Data System (ADS)

    Douch, Karim; Panet, Isabelle; Pajot-Métivier, Gwendoline; Christophe, Bruno; Foulon, Bernard; Lequentrec-Lalancette, Marie-Françoise; Diament, Michel

    2015-12-01

    Moving-base gravity gradiometry has proven to be a convenient method to determine the Earth's gravity field. The ESA mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) has enabled to map the Earth gravity field and its gradients with a resolution of 80 km, leading to significant advances in physical oceanography and solid Earth physics. At smaller scales, airborne gravity gradiometry has been increasingly used during the past decade in mineral and hydrocarbon exploration. In both cases the sensitivity of gradiometers to the short wavelengths of the gravity field is of crucial interest. Here, we quantify and characterize the error on the gravity gradients estimated from measurements performed with a new instrument concept, called GREMLIT, for typical airborne conditions. GREMLIT is an ultra-sensitive planar gravitational gradiometer which consists in a planar acceleration gradiometer together with 3 gyroscopes. To conduct this error analysis, a simulation of a realistic airborne survey with GREMLIT is carried out. We first simulate realistic GREMLIT synthetic data, taking into account the acceleration gradiometer and gyroscope noises and biases and the variation of orientation of the measurement reference frame. Then, we estimate the gravity gradients from these data. Special attention is paid to the processing of the gyroscopes measurements whose accuracy is not commensurate with the ultra-sensitive gradiometer. We propose a method to calibrate the gyroscopes biases with a precision of the order 10^{-8} rad/s. In order to transform the tensor from the measurement frame to the local geodetic frame, we estimate the error induced when replacing the non-measured elements of the gravity gradient tensor by an a priori model. With the appropriate smoothing, we show that it is possible to achieve a precision better than 2E for an along-track spatial resolution of 2 km.

  4. Airborne Gravity Survey and Ground Gravity in Afghanistan: A Website for Distribution of Data

    USGS Publications Warehouse

    Abraham, Jared D.; Anderson, Eric D.; Drenth, Benjamin J.; Finn, Carol A.; Kucks, Robert P.; Lindsay, Charles R.; Phillips, Jeffrey D.; Sweeney, Ronald E.

    2008-01-01

    Afghanistan?s geologic setting suggests significant natural resource potential. Although important mineral deposits and petroleum resources have been identified, much of the country?s potential remains unknown. Airborne geophysical surveys are a well- accepted and cost-effective method for remotely obtaining information of the geological setting of an area. A regional airborne geophysical survey was proposed due to the security situation and the large areas of Afghanistan that have not been covered using geophysical exploration methods. Acting upon the request of the Islamic Republic of Afghanistan Ministry of Mines, the U.S. Geological Survey contracted with the U.S. Naval Research Laboratory to jointly conduct an airborne geophysical and remote sensing survey of Afghanistan. Data collected during this survey will provide basic information for mineral and petroleum exploration studies that are important for the economic development of Afghanistan. Additionally, use of these data is broadly applicable in the assessment of water resources and natural hazards, the inventory and planning of civil infrastructure and agricultural resources, and the construction of detailed maps. The U.S. Geological Survey is currently working in cooperation with the U.S. Agency of International Development to conduct resource assessments of the country of Afghanistan for mineral, energy, coal, and water resources, and to assess geologic hazards. These geophysical and remote sensing data will be used directly in the resource and hazard assessments.

  5. Airborne gravity gradiometer surveying of petroleum systems under Lake Tanganyika, Tanzania

    NASA Astrophysics Data System (ADS)

    Roberts, Doug; Chowdhury, Priyanka Roy; Lowe, Sharon Jenny; Christensen, Asbjorn Norlund

    2016-02-01

    The Lake Tanganyika South petroleum exploration block covers the southern portion of the Tanzanian side of Lake Tanganyika and is located within the East African Rift System. The rifting process has formed rotated fault blocks which provide numerous play types in the resulting basins. Interpretation of 2D seismic data from 1984 indicated that sufficient sediment thickness is present for hydrocarbon generation. The prospectivity of the lake sediment sequence is enhanced by large oil discoveries further north along the rift system at Lake Albert in Uganda. Airborne gravity gradiometry (AGG) has been used in the Lake Albert region to delineate the structural framework of sedimentary basins. Based on this analogy, in 2010 Beach Energy commissioned CGG to fly a FALCON AGG and high-resolution airborne magnetic survey over the Lake Tanganyika South block to provide data for mapping the basin architecture and estimating the depth to magnetic basement. A total of nearly 28000 line kilometres of data were acquired. The subsequent interpretation incorporated the AGG and magnetic data with available 2D seismic data, elevation model data, bathymetry, Landsat and regional geology information. The integrated data interpretation revealed that the Lake Tanganyika rifting structures occur as half-grabens that were formed through reactivation of Precambrian fault structures. Two major depocentres were identified in the magnetic depth-to-basement map in the north and in the west-central part of the survey area with sediment thicknesses in excess of 4 km and 3 km, respectively. Smaller, shallower depocentres (with less than 3 km of sediment) occur in the south-western region. This information was used to plan a 2100 km 2D marine seismic survey that was recorded in 2012. An interpretation of the results from the seismic survey confirmed a rifting structure similar to that encountered further north at Lake Albert in Uganda. Several targets were identified from the seismic sections for

  6. On the impact of airborne gravity data to fused gravity field models

    NASA Astrophysics Data System (ADS)

    Bolkas, Dimitrios; Fotopoulos, Georgia; Braun, Alexander

    2016-06-01

    In gravity field modeling, fused models that utilize satellite, airborne and terrestrial gravity observations are often employed to deal with erroneous terrestrially derived gravity datasets. These terrestrial datasets may suffer from long-wavelength systematic errors and inhomogeneous data coverage, which are not prevalent in airborne and satellite datasets. Airborne gravity acquisition plays an essential role in gravity field modeling, providing valuable information of the Earth's gravity field at medium and short wavelengths. Thus, assessing the impact of airborne gravity data to fused gravity field models is important for identifying problematic regions. Six study regions that represent different gravity field variability and terrestrial data point-density characteristics are investigated to quantify the impact of airborne gravity data to fused gravity field models. The numerical assessments of these representative regions resulted in predictions of airborne gravity impact for individual states and provinces in the USA and Canada, respectively. Prediction results indicate that, depending on the terrestrial data point-density and gravity field variability, the expected impact of airborne gravity can reach up to 3mGal (in terms of standard deviation) in Canada and Alaska (over areas of 1° × 1°). However, in the mainland US region, small changes are expected (0.2-0.4 mGal over areas of 1° × 1°) due to the availability of high spatial resolution terrestrial data. These results can serve as a guideline for setting airborne gravity data acquisition priorities and for improving future planning of airborne gravity surveys.

  7. GTE: a new FFT based software to compute terrain correction on airborne gravity surveys in spherical approximation.

    NASA Astrophysics Data System (ADS)

    Capponi, Martina; Sampietro, Daniele; Sansò, Fernando

    2016-04-01

    The computation of the vertical attraction due to the topographic masses (Terrain Correction) is still a matter of study both in geodetic as well as in geophysical applications. In fact it is required in high precision geoid estimation by the remove-restore technique and it is used to isolate the gravitational effect of anomalous masses in geophysical exploration. This topographical effect can be evaluated from the knowledge of a Digital Terrain Model in different ways: e.g. by means of numerical integration, by prisms, tesseroids, polyedra or Fast Fourier Transform (FFT) techniques. The increasing resolution of recently developed digital terrain models, the increasing number of observation points due to extensive use of airborne gravimetry and the increasing accuracy of gravity data represents nowadays major issues for the terrain correction computation. Classical methods such as prism or point masses approximations are indeed too slow while Fourier based techniques are usually too approximate for the required accuracy. In this work a new software, called Gravity Terrain Effects (GTE), developed in order to guarantee high accuracy and fast computation of terrain corrections is presented. GTE has been thought expressly for geophysical applications allowing the computation not only of the effect of topographic and bathymetric masses but also those due to sedimentary layers or to the Earth crust-mantle discontinuity (the so called Moho). In the present contribution we summarize the basic theory of the software and its practical implementation. Basically the GTE software is based on a new algorithm which, by exploiting the properties of the Fast Fourier Transform, allows to quickly compute the terrain correction, in spherical approximation, at ground or airborne level. Some tests to prove its performances are also described showing GTE capability to compute high accurate terrain corrections in a very short time. Results obtained for a real airborne survey with GTE

  8. Latest Advancement In Airborne Relative Gravity Instrumentation.

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2011-12-01

    Airborne gravity surveying has been performed with widely varying degrees of success since early experimentation with the Lacoste and Romberg dynamic meter in the 1950s. There are a number of different survey systems currently in operation including relative gravity meters and gradiometers. Airborne gravity is ideally suited to rapid, wide coverage surveying and is not significantly more expensive in more remote and inhospitable terrain which makes airborne measurements one of the few viable options available for cost effective exploration. As improved instrumentation has become available, scientific applications have also been able to take advantage for use in determining sub surface geologic structures, for example under ice sheets in Antarctica, and more recently direct measurement of the geoid to improve the vertical datum in the United States. In 2004, Lacoste and Romberg (now Micro-g Lacoste) decided to build on their success with the newly developed AirSea II dynamic meter and use that system as the basis for a dedicated airborne gravity instrument. Advances in electronics, timing and positioning technology created the opportunity to refine both the hardware and software, and to develop a truly turnkey system that would work well for users with little or no airborne gravity experience as well as those with more extensive experience. The resulting Turnkey Airborne Gravity System (TAGS) was successfully introduced in 2007 and has since been flown in applications from oil, gas and mineral exploration surveys to regional gravity mapping and geoid mapping. The system has been mounted in a variety of airborne platforms including depending on the application of interest. The development experience with the TAGS enabled Micro-g Lacoste to embark on a new project in 2010 to completely redesign the mechanical and electronic components of the system rather than continuing incremental upgrades. Building on the capabilities of the original TAGS, the objectives for the

  9. Improved Airborne Gravity Results Using New Relative Gravity Sensor Technology

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2013-12-01

    Airborne gravity data has contributed greatly to our knowledge of subsurface geophysics particularly in rugged and otherwise inaccessible areas such as Antarctica. Reliable high quality GPS data has renewed interest in improving the accuracy of airborne gravity systems and recent improvements in the electronic control of the sensor have increased the accuracy and ability of the classic Lacoste and Romberg zero length spring gravity meters to operate in turbulent air conditions. Lacoste and Romberg type gravity meters provide increased sensitivity over other relative gravity meters by utilizing a mass attached to a horizontal beam which is balanced by a ';zero length spring'. This type of dynamic gravity sensor is capable of measuring gravity changes on the order of 0.05 milliGals in laboratory conditions but more commonly 0.7 to 1 milliGal in survey use. The sensor may have errors induced by the electronics used to read the beam position as well as noise induced by unwanted accelerations, commonly turbulence, which moves the beam away from its ideal balance position otherwise known as the reading line. The sensor relies on a measuring screw controlled by a computer which attempts to bring the beam back to the reading line position. The beam is also heavily damped so that it does not react to most unwanted high frequency accelerations. However this heavily damped system is slow to react, particularly in turns where there are very high Eotvos effects. New sensor technology utilizes magnetic damping of the beam coupled with an active feedback system which acts to effectively keep the beam locked at the reading line position. The feedback system operates over the entire range of the system so there is now no requirement for a measuring screw. The feedback system operates at very high speed so that even large turbulent events have minimal impact on data quality and very little, if any, survey line data is lost because of large beam displacement errors. Airborne testing

  10. Airborne Gravity Gradiometry Resolves a Full Range of Gravity Frequencies

    NASA Astrophysics Data System (ADS)

    Mataragio, J.; Brewster, J.; Mims, J.

    2007-12-01

    Airborne Full Tensor Gradiometry (Air\\-FTGR) was flown at high altitude coincident with Airborne Gravity (AG) flown in 2003 in West Arnhem Land, Australia. A preliminary analysis of two data sets indicates that the Air\\-FTGR system has the capability of resolving intermediate to long wavelengths features that may be associated with relatively deeper geological structures. A comparison of frequency filtered slices and power spectral density (PSD) for both data sets using the short (> 5 km), intermediate (10 km) and long (20 km) wavelengths reveals that high altitude Air\\-FTGR data show greater response in high frequency anomalies than a conventional Airborne Gravity and matches well with the AG even at the longest wavelengths anomalies. The effect of line spacing and target resolution was examined between the two data sets. Reprocessed gradient and AG data at 2, 4 and 6 km line spacing suggest that Air\\-FTGR could be effectively flown at a comparatively wider line spacing to resolve similar targets the AG would resolve with tighter line spacing. Introduction Airborne Full Tensor Gradiometry (Air\\-FTGR) data have been available to the mining industry since 2002 and their use for geologic applications is well established. However, Air\\-FTGR data has been mostly considered and used in mapping and delineation of near surface geological targets. This is due to the fact that gravity gradiometer measurements are well suited to capture the high frequency signal associated with near\\-surface targets ( Li, 2001). This is possible because the gradiometer signal strength falls off with the cube of the distance to the target. Nonetheless, in recent years there has been an increasing demand from the mining, oil, and gas industry in utilizing Full Tensor Gravity Gradiometer as a mapping tool for both regional and prospect level surveys. Air\\-FTGR as a Regional Mapping Tool Several, relatively low altitude surveys have been successfully flown in Brazil, Canada and Australia

  11. Airborne Gravity Data Enhances NGS Experimental Gravimetric Geoid in Alaska

    NASA Astrophysics Data System (ADS)

    Holmes, S. A.; Childers, V. A.; Li, X.; Roman, D. R.

    2014-12-01

    The U.S. National Geodetic Survey [NGS], through their Gravity for the Redefinition of the American Vertical Datum [GRAV-D] program, continues to update its gravimetry holdings by flying new airborne gravity surveys over a large fraction of the USA and its territories. By 2022, NGS intends that all orthometric heights in the USA will be determined in the field by using a reliable national gravimetric geoid model to transform from geodetic heights obtained from GPS. Several airborne campaigns have already been flown over Alaska and its coastline. Some of this Alaskan coastal data have been incorporated into a new NGS experimental geoid model - xGEOID14. The xGEOID14 model is the first in a series of annual experimental geoid models that will incorporate NGS GRAV-D airborne data. This series provides a useful benchmark for assessing and improving current techniques by which the airborne and land-survey data are filtered and cleaned, and then combined with satellite gravity models, elevation data (etc.) with the ultimate aim of computing a geoid model that can support a national physical height system by 2022. Here we will examine the NGS GRAV-D airborne data in Alaska, and assess its contribution to xGEOID14. Future prospects for xGEOID15 will also be considered.

  12. The Role of Aircraft Motion in Airborne Gravity Data Quality

    NASA Astrophysics Data System (ADS)

    Childers, V. A.; Damiani, T.; Weil, C.; Preaux, S. A.

    2015-12-01

    Many factors contribute to the quality of airborne gravity data measured with LaCoste and Romberg-type sensors, such as the Micro-g LaCoste Turnkey Airborne Gravity System used by the National Geodetic Survey's GRAV-D (Gravity for the Redefinition of the American Vertical Datum) Project. For example, it is well documented that turbulence is a big factor in the overall noise level of the measurement. Turbulence is best controlled by avoidance; thus flights in the GRAV-D Project are only undertaken when the predicted wind speeds at flight level are ≤ 40 kts. Tail winds are known to be particularly problematic. The GRAV-D survey operates on a number of aircraft in a variety of wind conditions and geographic locations, and an obvious conclusion from our work to date is that the aircraft itself plays an enormous role in the quality of the airborne gravity measurement. We have identified a number of features of the various aircraft which can be determined to play a role: the autopilot, the size and speed of the aircraft, inherent motion characteristics of the airframe, tip tanks and other modifications to the airframe to reduce motion, to name the most important. This study evaluates the motion of a number of the GRAV-D aircraft and looks at the correlation between this motion and the noise characteristics of the gravity data. The GRAV-D Project spans 7 years and 42 surveys, so we have a significant body of data for this evaluation. Throughout the project, the sensor suite has included an inertial measurement unit (IMU), first the Applanix POSAv, and then later the Honeywell MicroIRS IMU as a part of a NovAtel SPAN GPS/IMU system. We compare the noise characteristics of the data with measures of aircraft motion (via pitch, roll, and yaw captured by the IMU) using a variety of statistical tools. It is expected that this comparison will support the conclusion that certain aircraft tend to work well with this type of gravity sensor while others tend to be problematic in

  13. Geophex airborne unmanned survey system

    SciTech Connect

    Won, I.J.; Taylor, D.W.A.

    1995-03-01

    The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This nonintrusive system will provide {open_quotes}stand-off{close_quotes} capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. This system permits two operators to rapidly conduct geophysical characterization of hazardous environmental sites. During a survey, the operators remain remote from, but within visual distance, of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak anomalies can be detected.

  14. Geophex Airborne Unmanned Survey System

    SciTech Connect

    Won, I.J.; Keiswetter, D.

    1995-10-01

    The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide {open_quotes}stand-off{close_quotes} capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. This system permits rapid geophysical characterization of hazardous environmental sites. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected.

  15. The Kauring Airborne Gravity Test Site, Western Australia

    NASA Astrophysics Data System (ADS)

    Lane, R. J.; Grujic, M.; Aravanis, T.; Tracey, R.; Dransfield, M.; Howard, D.; Smith, B.

    2009-12-01

    A test site for airborne gravity (AG) systems has been established at Kauring, approximately 100 km east of Perth, Western Australia. The site was chosen using a range of criteria that included being within 200 km of Jandakot Airport in Perth where most of the airborne systems would be based at one time or another when operating in Australia, being free of low level flight restrictions, having minimal human infrastructure in the central 20 by 20 km area, and the presence of gentle to rolling terrain rather than deeply incised topography or an extensive flat plain with very low relief. In anticipation of catering for airborne gravity gradiometer (AGG) systems, the site was required to have a gravity gradient feature with clear response in the wavelength range of 100 m to 2 km in a 5 by 5 km core region. The existence of closely-spaced, high quality ground gravity data would have been a positive factor for selecting a test site, but a search of the national gravity database indicated that there were no such data sets in the search area. Consequently, a ground vertical gravity acquisition program for the chosen site at Kauring was arranged by the Geological Survey of Western Australia (GSWA), Geoscience Australia (GA), and Rio Tinto Exploration. To support AG system tests, a 150 by 150 km area was covered with a maximum station spacing of 2 by 2 km, and the central area of 20 by 20 km was covered with a maximum station spacing of 0.5 by 0.5 km. These data are freely available from GSWA and GA. To support AGG system tests, the core 5 by 5 km area would need to have stations with much closer spacing (e.g., 100 by 100 m). A variety of publicly available digital terrain data sets are available (e.g., SRTM 3-second data (~90 m), ASTER GDEM 1-second data (~30 m), GEODATA 9-second data (~300 m), etc.). Acquisition of a LIDAR-based high-resolution digital terrain model (DTM) for the central 20 by 20 km area is being considered. A DTM of this nature for the core 5 by 5 km area

  16. On the spectral combination of satellite gravity model, terrestrial and airborne gravity data for local gravimetric geoid computation

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Wang, Yan Ming

    2016-07-01

    One of the challenges for geoid determination is the combination of heterogeneous gravity data. Because of the distinctive spectral content of different data sets, spectral combination is a suitable candidate for its solution. The key to have a successful combination is to determine the proper spectral weights, or the error degree variances of each data set. In this paper, the error degree variances of terrestrial and airborne gravity data at low degrees are estimated by the aid of a satellite gravity model using harmonic analysis. For higher degrees, the error covariances are estimated from local gravity data first, and then used to compute the error degree variances. The white and colored noise models are also used to estimate the error degree variances of local gravity data for comparisons. Based on the error degree variances, the spectral weights of satellite gravity models, terrestrial and airborne gravity data are determined and applied for geoid computation in Texas area. The computed gravimetric geoid models are tested against an independent, highly accurate geoid profile of the Geoid Slope Validation Survey 2011 (GSVS11). The geoid computed by combining satellite gravity model GOCO03S and terrestrial (land and DTU13 altimetric) gravity data agrees with GSVS11 to ±1.1 cm in terms of standard deviation along a line of 325 km. After incorporating the airborne gravity data collected at 11 km altitude, the standard deviation is reduced to ±0.8 cm. Numerical tests demonstrate the feasibility of spectral combination in geoid computation and the contribution of airborne gravity in an area of high quality terrestrial gravity data. Using the GSVS11 data and the spectral combination, the degree of correctness of the error spectra and the quality of satellite gravity models can also be revealed.

  17. Geophex Airborne Unmanned Survey System

    SciTech Connect

    Won, I.L.; Keiswetter, D.

    1995-12-31

    Ground-based surveys place personnel at risk due to the proximity of buried unexploded ordnance (UXO) items or by exposure to radioactive materials and hazardous chemicals. The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide stand-off capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected. The Geophex Airborne Unmanned Survey System (GAUSS) is designed to detect and locate small-scale anomalies at hazardous sites using magnetic and electromagnetic survey techniques. The system consists of a remotely-piloted, radio-controlled, model helicopter (RCH) with flight computer, light-weight geophysical sensors, an electronic positioning system, a data telemetry system, and a computer base-station. The report describes GAUSS and its test results.

  18. Gravity changes in mid-west Greenland from GOCE gravity model and gradient data using ground and airborne gravity.

    NASA Astrophysics Data System (ADS)

    Tscherning, Carl Christian; Herceg, Matija

    2014-05-01

    GOCE (ESA's Gravity and Ocean Circulation Explorer) TRF (terrestrial reference frame) vertical anomalous gradients (Tzz) from the periods winter 2009 and summer 2012 have been used to determine gravity anomalies in mid-west Greenland, where a large mass-loss has been detected using GRACE. As additional data were used the GOCE DIR-3 model and ground gravity at the coast on solid rock, where no mass loss is expected. The methods of Least-Squares Collocation (LSC) and the Reduced Point Mass (RPM) methods have been used, however only LSC included the ground data. The latter method also permits the computation of error-estimates, which range from 3 mgal at the coast to 19 mgal 75 km from the coast in Eastern direction towards the ice-cap. The gravity anomaly differences vary from -30 mgal to 30 mgal. It is negative (showing mass loss) around the Jacobshavn Isbrae (latitude 69o15', longitude 49o W-50oW, where the yearly mass-loss has been estimated to correspond to -2 mgal, i.e. about -7 mgal for the period considered. The computed change range from 0 to -10 mgal in the area, with the error estimated to increase from 4 mgal to 15 mgal from West to East. This shows the capability of using GOCE Tzz and ground gravity to determine mass changes. The GOCE DIR-3 model was also used to evaluate gravity values in the points of the Greenland airborne gravity survey performed in 1991 and 1992. The differences had a mean value of 0.9 and a standard deviation of 17.3 mgal for all of Greenland. In the South-West area the mean of the differences was 0.15 and the standard deviation 7.14. This indicate that possibly no total mass loss has occurred in Greenland from 1992 to 2012.

  19. Marine Geoid Undulation Assessment Over South China Sea Using Global Geopotential Models and Airborne Gravity Data

    NASA Astrophysics Data System (ADS)

    Yazid, N. M.; Din, A. H. M.; Omar, K. M.; Som, Z. A. M.; Omar, A. H.; Yahaya, N. A. Z.; Tugi, A.

    2016-09-01

    Global geopotential models (GGMs) are vital in computing global geoid undulations heights. Based on the ellipsoidal height by Global Navigation Satellite System (GNSS) observations, the accurate orthometric height can be calculated by adding precise and accurate geoid undulations model information. However, GGMs also provide data from the satellite gravity missions such as GRACE, GOCE and CHAMP. Thus, this will assist to enhance the global geoid undulations data. A statistical assessment has been made between geoid undulations derived from 4 GGMs and the airborne gravity data provided by Department of Survey and Mapping Malaysia (DSMM). The goal of this study is the selection of the best possible GGM that best matches statistically with the geoid undulations of airborne gravity data under the Marine Geodetic Infrastructures in Malaysian Waters (MAGIC) Project over marine areas in Sabah. The correlation coefficients and the RMS value for the geoid undulations of GGM and airborne gravity data were computed. The correlation coefficients between EGM 2008 and airborne gravity data is 1 while RMS value is 0.1499.In this study, the RMS value of EGM 2008 is the lowest among the others. Regarding to the statistical analysis, it clearly represents that EGM 2008 is the best fit for marine geoid undulations throughout South China Sea.

  20. First application of airborne gravity to oil exploration in the Shengli oil province, eastern China

    NASA Astrophysics Data System (ADS)

    Li, Wenyong; Zhoud, Jianxin; Liu, Yanxu; Xu, Jianchun

    2015-07-01

    An airborne gravity survey was successfully conducted over the Dongying, Gudao and Gudong oilfields of Shengli oil province, eastern China. These survey areas cover onshore and offshore regions of the south-west Bohai Sea. The data were processed using the potential field transformation approach. The derived Bouguer gravity data correlate well with features such as known faults, swells and sags identified by earlier seismic survey and drilling data. The depth to the Cenozoic basement in the study area, including the Dongying, Gudao, and Gudong oilfields, was calculated by means of gravity inversion constrained by seismic and drilling data. The differences between the depths to the Cenozoic basement calculated from gravity anomaly and those determined by the earlier seismic and drilling data are less than 5%.

  1. Environmental applications of gravity surveying

    SciTech Connect

    Barrows, L.J. ); Nesbit, L.C. ); Khan, W.A. )

    1994-04-01

    The Allis Park Sanitary Landfill Company developed a new landfill near Onway, Michigan in an area which has glacial alluvium and glacial till overlying limestone. There are several solution karst features in the region and some critics had maintained that a new karst collapse could rupture the liner system and allow escape of leachate into the groundwater. The gravity survey was conducted to determine the extent of any karst development at the site. The first portion of the survey was two profiles over some karst features located about five miles southeast of the proposed landfill. These showed negative gravity anomalies. The survey of the proposed landfill site resulted in a 50 microGal contour map of the area and also showed a negative anomaly. This could be due to either elevation variations on the till to limestone bedrock surface or to karst development within the limestone. Because there was no evidence of historic development of new karst features in the region, the gravity anomaly was not further investigated. In another gravity survey, a large retail department store had been remodeled and extended over an area previously occupied by an auto service center. The removal of a waste oil storage tank (UST) had not been documented and the environmental consultant (KEMRON, Inc.) proposed that a gravity survey be used to find the tank location. This proposal was based on calculations of the gravity effects of a UST. The survey resulted in a four-microGal contour map which showed a couple of anomalies which could be due to a tank or a backfilled tank excavation. During the survey, a store employee identified the previous location of the tank and explained that she had personally witnessed its removal. Based on the employee's eye-witness account of the tank removal and the coincidence of her indicated tank location with one of the gravity anomalies the authors recommended the site be granted clean closure.

  2. New airborne-gravity and satellite gravity views of crustal structure in Antarctica (Invited)

    NASA Astrophysics Data System (ADS)

    Ferraccioli, F.; Kusznir, N. J.; Scheinert, M.; Jordan, T. A.; Bell, R. E.; Blankenship, D. D.; Young, D. A.; Aitken, A.; Forsberg, R.; Anderson, L.; Jokat, W.; Mieth, M.; Armadillo, E.

    2013-12-01

    Gravity anomalies provide a tool to study crustal structure, effective elastic thickness, and isostatic and tectonic processes. Over the last 10 years major airborne gravity surveys were flown by the international community over several Antarctic frontiers. The longer-wavelength Antarctic gravity anomaly field is increasingly better resolved with satellite-gravity. These recent airborne and satellite gravity datasets provide novel perspectives on Antarctic crustal structure and geodynamic evolution. We review results from some of these surveys over the Gamburtsev Subglacial Mountains, Dronning Maud Land, the Wilkes Subglacial Basin, the Transantarctic Mountains and the West Antarctic Rift System and present gravity modelling outputs of crustal thickness for these regions. We contrast these gravity results with a seismically-derived estimation of Antarctic crustal thickness (Baranov and Morelli, 2013, Tectonophys). Anomalously thick East Antarctic crust lies beneath the Gamburtsev Mountains and parts of Dronning Maud Land (50-58 km). Crustal thickening may stem from the collision of a mosaic of East Antarctic crustal provinces in Meso to Neoproterozoic times (Ferraccioli et al., 2011, Nature), or during younger Edicaran to early Cambrian 'Pan-African age' orogenic events. The preservation of such thick crust provides significant support for the high bedrock topography in East Antarctica. Additional flexural uplift along the flanks of the Permian to Cretaceous East Antarctic Rift System helps explain the enigmatic Gamburtsev Mountains. Lithospheric flexure along the flank of the West Antarctic Rift System (WARS) may explain the Transantarctic Mountains (TAM), the longest and highest non-compressional mountain range on Earth. Whether the Wilkes Subglacial Basin also developed in response to lithospheric flexure is debated. Our gravity models image thicker crust beneath the Transantarctic Mountains (TAM) (ca 40 km thick), compared to the relatively thinner crust (30

  3. Fast 3D inversion of airborne gravity-gradiometry data using Lanczos bidiagonalization method

    NASA Astrophysics Data System (ADS)

    Meng, Zhaohai; Li, Fengting; Zhang, Dailei; Xu, Xuechun; Huang, Danian

    2016-09-01

    We developed a new fast inversion method for to process and interpret airborne gravity gradiometry data, which was based on Lanczos bidiagonalization algorithm. Here, we describe the application of this new 3D gravity gradiometry inversion method to recover a subsurface density distribution model from the airborne measured gravity gradiometry anomalies. For this purpose, the survey area is divided into a large number of rectangular cells with each cell possessing a constant unknown density. It is well known that the solution of large linear gravity gradiometry is an ill-posed problem since using the smoothest inversion method is considerably time consuming. We demonstrate that the Lanczos bidiagonalization method can be an appropriate algorithm to solve a Tikhonov solver time cost function for resolving the large equations within a short time. Lanczos bidiagonalization is designed to make the very large gravity gradiometry forward modeling matrices to become low-rank, which will considerably reduce the running time of the inversion method. We also use a weighted generalized cross validation method to choose the appropriate Tikhonov parameter to improve inversion results. The inversion incorporates a model norm that allows us to attain the smoothing and depth of the solution; in addition, the model norm counteracts the natural decay of the kernels, which concentrate at shallow depths. The method is applied on noise-contaminated synthetic gravity gradiometry data to demonstrate its suitability for large 3D gravity gradiometry data inversion. The airborne gravity gradiometry data from the Vinton Salt Dome, USE, were considered as a case study. The validity of the new method on real data is discussed with reference to the Vinton Dome inversion result. The intermediate density values in the constructed model coincide well with previous results and geological information. This demonstrates the validity of the gravity gradiometry inversion method.

  4. From Mars to Greenland: Charting gravity with space and airborne instruments - Fields, tides, methods, results

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L. (Editor)

    1992-01-01

    This symposium on space and airborne techniques for measuring gravity fields, and related theory, contains papers on gravity modeling of Mars and Venus at NASA/GSFC, an integrated laser Doppler method for measuring planetary gravity fields, observed temporal variations in the earth's gravity field from 16-year Starlette orbit analysis, high-resolution gravity models combining terrestrial and satellite data, the effect of water vapor corrections for satellite altimeter measurements of the geoid, and laboratory demonstrations of superconducting gravity and inertial sensors for space and airborne gravity measurements. Other papers are on airborne gravity measurements over the Kelvin Seamount; the accuracy of GPS-derived acceleration from moving platform tests; airborne gravimetry, altimetry, and GPS navigation errors; controlling common mode stabilization errors in airborne gravity gradiometry, GPS/INS gravity measurements in space and on a balloon, and Walsh-Fourier series expansion of the earth's gravitational potential.

  5. Preliminary geoid mapping results by Fugro's improved Micro-g LaCoste turnkey airborne gravity system

    NASA Astrophysics Data System (ADS)

    Zhong, D.; Kingdon, R. W.

    2015-07-01

    In this paper, we introduce the Micro-g LaCoste Turnkey Airborne Gravity System (TAGS) with Fugro's improved gravity processing and geoid modeling software package for regional gravity field mapping and geoid determination. Three test areas with different topographic characteristics under the Gravity for the Redefinition of the AmericanVertical Datum (GRAV-D) project of theUSNOAA National Geodetic Surveys (NGS) were used for case studies and determine the available accuracy of the system. The preliminary results of all these test cases show that the system with Fugro's improved gravity and geoid processing software package is able to achieve a comparable geoid mapping result to traditional terrestrial methods.

  6. Airborne Geophysical Surveys Applied to Hydrocarbon Resource Development Environmental Studies

    NASA Astrophysics Data System (ADS)

    Smith, B. D.; Ball, L. B.; Finn, C.; Kass, A.; Thamke, J.

    2014-12-01

    Application of airborne geophysical surveys ranges in scale from detailed site scale such as locating abandoned well casing and saline water plumes to landscape scale for mapping hydrogeologic frameworks pertinent to ground water and tectonic settings relevant to studies of induced seismicity. These topics are important in understanding possible effects of hydrocarbon development on the environment. In addition airborne geophysical surveys can be used in establishing baseline "snapshots", to provide information in beneficial uses of produced waters, and in mapping ground water resources for use in well development. The U.S. Geological Survey (USGS) has conducted airborne geophysical surveys over more than 20 years for applications in energy resource environmental studies. A majority of these surveys are airborne electromagnetic (AEM) surveys to map subsurface electrical conductivity related to plumes of saline waters and more recently to map hydrogeologic frameworks for ground water and plume migration. AEM surveys have been used in the Powder River Basin of Wyoming to characterize the near surface geologic framework for siting produced water disposal ponds and for beneficial utilization in subsurface drip irrigation. A recent AEM survey at the Fort Peck Reservation, Montana, was used to map both shallow plumes from brine pits and surface infrastructure sources and a deeper concealed saline water plume from a failed injection well. Other reported applications have been to map areas geologically favorable for shallow gas that could influence drilling location and design. Airborne magnetic methods have been used to image the location of undocumented abandoned well casings which can serve as conduits to the near surface for coproduced waters. They have also been used in conjunction with geologic framework studies to understand the possible relationships between tectonic features and induced earthquakes in the Raton Basin. Airborne gravity as well as developing deeper

  7. Magnetic airborne survey - geophysical flight

    NASA Astrophysics Data System (ADS)

    de Barros Camara, Erick; Nei Pereira Guimarães, Suze

    2016-06-01

    This paper provides a technical review process in the area of airborne acquisition of geophysical data, with emphasis for magnetometry. In summary, it addresses the calibration processes of geophysical equipment as well as the aircraft to minimize possible errors in measurements. The corrections used in data processing and filtering are demonstrated with the same results as well as the evolution of these techniques in Brazil and worldwide.

  8. Quantitative interpretation of airborne gravity gradiometry data for mineral exploration

    NASA Astrophysics Data System (ADS)

    Martinez, Cericia D.

    In the past two decades, commercialization of previously classified instrumentation has provided the ability to rapidly collect quality gravity gradient measurements for resource exploration. In the near future, next-generation instrumentation are expected to further advance acquisition of higher-quality data not subject to pre-processing regulations. Conversely, the ability to process and interpret gravity gradiometry data has not kept pace with innovations occurring in data acquisition systems. The purpose of the research presented in this thesis is to contribute to the understanding, development, and application of processing and interpretation techniques available for airborne gravity gradiometry in resource exploration. In particular, this research focuses on the utility of 3D inversion of gravity gradiometry for interpretation purposes. Towards this goal, I investigate the requisite components for an integrated interpretation workflow. In addition to practical 3D inversions, components of the workflow include estimation of density for terrain correction, processing of multi-component data using equivalent source for denoising, quantification of noise level, and component conversion. The objective is to produce high quality density distributions for subsequent geological interpretation. I then investigate the use of the inverted density model in orebody imaging, lithology differentiation, and resource evaluation. The systematic and sequential approach highlighted in the thesis addresses some of the challenges facing the use of gravity gradiometry as an exploration tool, while elucidating a procedure for incorporating gravity gradient interpretations into the lifecycle of not only resource exploration, but also resource modeling.

  9. Airborne detection of asperities: Linking aerogravimetry surveys and earthquake studies

    NASA Astrophysics Data System (ADS)

    Meyer, U.; Boedecker, G.

    2003-04-01

    During the last decade, airborne gravimetric surveys have become a reliable and useful geophysical method to explore mid to large scale geologic settings. Ocean continent boundaries down to seamounts are detectable using conventional scalar, platform stabilized airborne gravimetry systems. New systems such as 3-D strap-down instruments promise a better spatial resolution recovering the gravity vector. Airborne gravimetric gradiometer systems are already able to detect small scale gradients in high spatial resolution. Following this trend in aerogravimetry, new research applications are emerging. One of the most challenging and interesting new aspects of airborne gravimetry is the systematic search for asperity structures. Asperities are patches of the oceanic or continental crust that are able to store more stress than the surrounding material. If due to stress overload or other mechanic forces the asperity breaks, up to mega-thrust earthquakes are triggered. The character of an asperity to carry more stress than the weaker environment must be related to its physical properties such as composition, thickness and density. Questions connected to define and detect an asperity are: How large is an asperity? Do asperities have sharp boundaries? Are asperities isolated structures? Do asperities have special gravimetric signatures? Wells et al. (2000) found that off southern Chile slip maxima from earthquakes coincide with forearc gravity lows. It is well accepted that in this region seismicity is a product of the subduction on the active continental margin. It is still debated whether subducted asperities from the oceanic plate are individual earthquake sources or if they i.e. trigger the break of asperities in the continental crust. Apart from this, very few investigations have been made trying to connect gravimetry and asperities. Therefore, the GeoForschungsZentrum Potsdam in collaboration with Bayerische Akademie der Wissenschaften in Munich , FU Berlin

  10. Gravity Anomaly Assessment Using Ggms and Airborne Gravity Data Towards Bathymetry Estimation

    NASA Astrophysics Data System (ADS)

    Tugi, A.; Din, A. H. M.; Omar, K. M.; Mardi, A. S.; Som, Z. A. M.; Omar, A. H.; Yahaya, N. A. Z.; Yazid, N.

    2016-09-01

    The Earth's potential information is important for exploration of the Earth's gravity field. The techniques of measuring the Earth's gravity using the terrestrial and ship borne technique are time consuming and have limitation on the vast area. With the space-based measuring technique, these limitations can be overcome. The satellite gravity missions such as Challenging Mini-satellite Payload (CHAMP), Gravity Recovery and Climate Experiment (GRACE), and Gravity-Field and Steady-State Ocean Circulation Explorer Mission (GOCE) has introduced a better way in providing the information on the Earth's gravity field. From these satellite gravity missions, the Global Geopotential Models (GGMs) has been produced from the spherical harmonics coefficient data type. The information of the gravity anomaly can be used to predict the bathymetry because the gravity anomaly and bathymetry have relationships between each other. There are many GGMs that have been published and each of the models gives a different value of the Earth's gravity field information. Therefore, this study is conducted to assess the most reliable GGM for the Malaysian Seas. This study covered the area of the marine area on the South China Sea at Sabah extent. Seven GGMs have been selected from the three satellite gravity missions. The gravity anomalies derived from the GGMs are compared with the airborne gravity anomaly, in order to figure out the correlation (R2) and the root mean square error (RMSE) of the data. From these assessments, the most suitable GGMs for the study area is GOCE model, GO_CONS_GCF_2_TIMR4 with the R2 and RMSE value of 0.7899 and 9.886 mGal, respectively. This selected model will be used in the estimating the bathymetry for Malaysian Seas in future.

  11. Requirements analysis of airborne gravity gradiometry on moving-based platform

    NASA Astrophysics Data System (ADS)

    Tu, L.; Li, Z.; Wu, W.

    2014-12-01

    Airborne gravity and gravity gradient measurement are the most effective ways for the earth gravitational field measurement. Gravity gradient is a derivative of gravity acceleration, due to the high order feature of gravity gradient, it is more sensitive to short wave component, and can reflect the details of the source so that the gravity gradient measurement has wide applications in geophysical science, resource exploration, and inertial navigation. Airborne gravity gradient measurement uses the plane or ship as the platform, and it is efficient and high precision. In this paper, We compared the gravity and gravity gradient measurement, and analyzed the advantages of the gravity gradient measurement compared with gravity measurement. The airborne gravity gradient measurement system and the inertial stabilization platform were discussed. By setting a goal sensitivity of the gravity gradient measurement being 1 E/√Hz, the key factors of the stabilized platform, namely the pointing accuracy, pointing stability, and gyroscope random drift, are 0.5°, 0.01°/hr/√Hz, and 0.01°/hr respectively. Compared with the airborne gravity measurement whose goal sensitivity is 1mGal/√Hz, the requirements of moving-based gravity gradient measurement on the inertial stabilization platform is significantly lower and hence easy to realize, and the major reason is the differential measurement mode being used.

  12. Infrared airborne spectroradiometer survey results in the western Nevada area

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.; Kuo, J. T.

    1982-01-01

    The Mark II airborne spectroradiometer system was flown over several geologic test sites in western Nevada. The infrared mineral absorption bands were observed and recorded for the first time using an airborne system with high spectral resolution in the 2.0 to 2.5 micron region. The data show that the hydrothermal alteration zone minerals, carbonates, and other minerals are clearly visible in the airborne survey mode. The finer spectral features that distinguish the various minerals with infrared bands are also clearly visible in the airborne survey data. Using specialized computer pattern recognition methods, it is possible to identify mineralogy and map alteration zones and lithologies by airborne spectroradiometer survey techniques.

  13. Towards an improved knowledge of the gravity field and geoid in Antarctica utilizing airborne gravimetry

    NASA Astrophysics Data System (ADS)

    Scheinert, M.

    2011-12-01

    For the determination of high-resolution earth's gravity field models (EGM) satellite measurements have to be combined with terrestrial gravity anomalies. In this respect, Antarctica remains one of the largest data gaps in the global coverage of terrestrial gravity data. This is especially critical, since the polar data gap resulting from the orbit inclination of GOCE, the recent and most powerful satellite gravity mission, amounts to a cap of about 1,300 km diameter at the pole. Furthermore, the limitation to a certain harmonic degree of resolution prevent a complete, high resolution data coverage to be obtained from the dedicated gravity missions only. For Antarctica, characterized by a hostile environment and difficult logistic conditions, airborne gravimetry offers the most powerful technique to survey large areas. In the perspective of geodesy, the coordination of activities is in the focus of the "Antarctic Geoid Project" (AntGP), Sub-Commission 2.4f of the International Association of Geodesy (IAG), and of project 3 "Physical Geodesy" within the GIANT program of the Standing Scientific Group on Geosciences (SSG-G) of the Scientific Committee on Antarctic Research (SCAR), both chaired by the author. This contribution will review the progress made realizing gravity surveys in Antarctica. Often initiated by a geophysically focussed rationale a great number of airborne surveys were accomplished during the last years. Furthermore, new plans shall be discussed. In this context, the initiative to make use of the new German "High Altitude and Long Range Research Aircraft" (HALO) for geoscientific applications will be presented. Based on a modified Gulfstream G550 jet it opens unprecedented possibilities for atmospheric and geoscientific research. Being the first geoscientific mission, GEOHALO shall demonstrate the feasibility and performance of the geodetic-geophysical instrumentation to gain airborne gravimetry and magnetometry measurements, GNSS direct, reflected

  14. GREMLIT : an airborne gravity gradiometer inheriting from GOCE

    NASA Astrophysics Data System (ADS)

    Foulon, B.; Douch, K.; Christophe, B.; Panet, I.; Boulanger, D.; Lebat, V.

    2012-04-01

    The knowledge of the gravity field of the Earth has been considerably improved thanks to global positioning satellites constellations and to space gravity measurements from recent GRACE and GOCE missions. But the spatial resolution of those gravity data essentially addresses the large and medium wavelengths of the field (down to a resolution of 90km) and it is therefore essential to complete them at the shorter wavelengths in particular in the areas where spatial distribution and quality of ground data remain quite uneven like in high mountain or coastal areas. To this aim, gravity gradiometry systems may be particularly suitable by covering the land/sea transition zone with a uniform precision, and a spatial resolution higher than from gravimetry. The GREMLIT instrument is taking advantage of technologies, formerly developed by ONERA for the GRACE and GOCE space missions. The gradiometer is built using a planar configuration for the gradiometer and is mounted on a dedicated stabilized platform which is controlled by the common mode outputs of the instrument itself to achieve a sufficient rejection ratio of the perturbations/vibrations induced by the airborne environment. Such a planar configuration is especially well suited to sustain the proof-mass levitation in the Earth's gravity field. It also presents intrinsic linearity, which minimizes the aliasing due to high frequency vibrations or motions generated outside the measurement bandwidth. The compactness of the design ensures excellent dimensional stability, good thermal homogeneity and makes the conception of the stabilized platform easier. The performance objective is between 0.1 and 1 Eötvös taking into account the difficulty of measurements onboard an aircraft by comparison to the particularly conducive satellite measurement environment.

  15. Resolving bathymetry from airborne gravity along Greenland fjords

    USGS Publications Warehouse

    Boghosian, Alexandra; Tinto, Kirsty; Cochran, James R.; Porter, David; Elieff, Stefan; Burton, Bethany; Bell, Robin E.

    2015-01-01

    Recent glacier mass loss in Greenland has been attributed to encroaching warming waters, but knowledge of fjord bathymetry is required to investigate this mechanism. The bathymetry in many Greenland fjords is unmapped and difficult to measure. From 2010 to 2012, National Aeronautics and Space Administration's Operation IceBridge collected a unique set of airborne gravity, magnetic, radar, and lidar data along the major outlet glaciers and fjords in Greenland. We applied a consistent technique using the IceBridge gravity data to create 90 bathymetric profiles along 54 Greenland fjords. We also used this technique to recover subice topography where warm or crevassed ice prevents the radar system from imaging the bed. Here we discuss our methodology, basic assumptions and error analysis. We present the new bathymetry data and discuss observations in six major regions of Greenland covered by IceBridge. The gravity models provide a total of 1950 line kilometers of bathymetry, 875 line kilometers of subice topography, and 12 new grounding line depths.

  16. Resolving bathymetry from airborne gravity along Greenland fjords

    NASA Astrophysics Data System (ADS)

    Boghosian, Alexandra; Tinto, Kirsty; Cochran, James R.; Porter, David; Elieff, Stefan; Burton, Bethany L.; Bell, Robin E.

    2015-12-01

    Recent glacier mass loss in Greenland has been attributed to encroaching warming waters, but knowledge of fjord bathymetry is required to investigate this mechanism. The bathymetry in many Greenland fjords is unmapped and difficult to measure. From 2010 to 2012, National Aeronautics and Space Administration's Operation IceBridge collected a unique set of airborne gravity, magnetic, radar, and lidar data along the major outlet glaciers and fjords in Greenland. We applied a consistent technique using the IceBridge gravity data to create 90 bathymetric profiles along 54 Greenland fjords. We also used this technique to recover subice topography where warm or crevassed ice prevents the radar system from imaging the bed. Here we discuss our methodology, basic assumptions and error analysis. We present the new bathymetry data and discuss observations in six major regions of Greenland covered by IceBridge. The gravity models provide a total of 1950 line kilometers of bathymetry, 875 line kilometers of subice topography, and 12 new grounding line depths.

  17. High-resolution airborne gravity imaging over James Ross Island (West Antarctica)

    USGS Publications Warehouse

    Jordan, T.A.; Ferraccioli, F.; Jones, P.C.; Smellie, J.L.; Ghidella, M.; Corr, H. F. J.; Zakrajsek, A.F.

    2007-01-01

    James Ross Island (JRI) exposes a Miocene-Recent alkaline basaltic volcanic complex that developed in a back-arc, east of the northern Antarctic Peninsula. JRI has been the focus of several geological studies because it provides a window on Neogene magmatic processes and paleoenvironments. However, little is known about its internal structure. New airborne gravity data were collected as part of the first high-resolution aerogeophysical survey flown over the island and reveal a prominent negative Bouguer gravity anomaly over Mt Haddington. This is intriguing as basaltic volcanoes are typically associated with positive Bouguer anomalies, linked to underlying mafic intrusions. The negative Bouguer anomaly may be associated with a hitherto unrecognised low-density sub-surface body, such as a breccia-filled caldera, or a partially molten magma chamber.

  18. Final report. Electro-Seise, Inc., Airborne Survey

    SciTech Connect

    Schulte, Ralph

    2001-06-01

    The Rocky Mountain Oilfield Testing Center (RMOTC) has recently completed a test of an airborne microgravity and electric field sensing technology developed by Electro-Seise, Inc. of Fort Worth, Texas. The test involved the use of a single engine airplane to gather data over the Teapot Dome oil field along a tight grid spacing and along thirty (30) survey lines. The resultant gravity structure maps, based on the field data, were found to overlay the known structure of Teapot Dome. In addition, fault maps, based on the field data, were consistent with the known fault strike at Teapot Dome. Projected hydrocarbon thickness maps corresponded to some of the known production histories at RMOTC. Exceptions to the hydrocarbon thickness maps were also found to be true.

  19. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1954-01-01

    Airborne radioactivity surveys totaling 5, 600 traverse miles were made in 10 areas in Florida, which were thought to be geologically favorable for deposits of uraniferous phosphate. Abnormal radioactivity was recorded in 8 of the 10 areas surveyed. The anomalies are located in Bradford, Clay, Columbia, DeSoto, Dixie, Lake, Marion, Orange, Sumter, Taylor, and Union Counties. Two of the anomalies were investigated briefly on the ground. One resulted from a deposit of river-pebble phosphate in the Peace River valley; the river-pebble samples contain an average of 0.013 percent equivalent uranium. The other anomaly resulted from outcrops of leached phosphatic rock containing as much as 0. 016 percent equivalent uranium. Several anomalies in other areas were recorded at or near localities where phosphate deposits have been reported.

  20. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1953-01-01

    Airborne radioactivity surveys totalling 5,600 traverse miles were made in ten areas in Florida, which were thought to be geologically favorable for the occurrence of uraniferous phosphate deposits. Abnormal radioactivity was recorded in eight of the ten areas surveyed. The anomalies are located in Bradford, Clay, Columbia, DeSoto, Dixie, Lake, Marion, Orange, Sumter, Taylor, and Union Counties. Two of the anomalies were investigated briefly on the ground. One resulted from a deposit of river-pebble phosphate in the Peace River valley; samples of the river pebble contain an average of 0.013 percent equivalent uranium. The other anomaly resulted from outcrops of leached phosphate rock containing as much as 0.016 percent equivalent uranium. Several anomalies in other areas were recorded at or near localities where phosphate deposits have been reported to occur.

  1. Gravity for Detecting Caves: Airborne and Terrestrial Simulations Based on a Comprehensive Karstic Cave Benchmark

    NASA Astrophysics Data System (ADS)

    Braitenberg, Carla; Sampietro, Daniele; Pivetta, Tommaso; Zuliani, David; Barbagallo, Alfio; Fabris, Paolo; Rossi, Lorenzo; Fabbri, Julius; Mansi, Ahmed Hamdi

    2016-04-01

    Underground caves bear a natural hazard due to their possible evolution into a sink hole. Mapping of all existing caves could be useful for general civil usages as natural deposits or tourism and sports. Natural caves exist globally and are typical in karst areas. We investigate the resolution power of modern gravity campaigns to systematically detect all void caves of a minimum size in a given area. Both aerogravity and terrestrial acquisitions are considered. Positioning of the gravity station is fastest with GNSS methods the performance of which is investigated. The estimates are based on a benchmark cave of which the geometry is known precisely through a laser-scan survey. The cave is the Grotta Gigante cave in NE Italy in the classic karst. The gravity acquisition is discussed, where heights have been acquired with dual-frequency geodetic GNSS receivers and Total Station. Height acquisitions with non-geodetic low-cost receivers are shown to be useful, although the error on the gravity field is larger. The cave produces a signal of -1.5 × 10-5 m/s2, with a clear elliptic geometry. We analyze feasibility of airborne gravity acquisitions for the purpose of systematically mapping void caves. It is found that observations from fixed wing aircraft cannot resolve the caves, but observations from slower and low-flying helicopters or drones do. In order to detect the presence of caves the size of the benchmark cave, systematic terrestrial acquisitions require a density of three stations on square 500 by 500 m2 tiles. The question has a large impact on civil and environmental purposes, since it will allow planning of urban development at a safe distance from subsurface caves. The survey shows that a systematic coverage of the karst would have the benefit to recover the position of all of the greater existing void caves.

  2. Relation of Topography to Airborne Gravity in Afghanistan and the Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Jung, W.; Brozena, J. M.; Peters, M. F.

    2012-12-01

    As part of a multi-sensor, multi-disciplinary aerogeophysical survey, the US Naval Research Laboratory collected airborne gravity over most of Afghanistan in 2006 (http://pubs.usgs.gov/of/2008/1089/Afghan_grv.html). The data were measured using a pair of ZLS Corporation air-sea gravimeters 7 km altitude above mean sea level aboard an NP-3D Orion aircraft operated by the US Navy's Scientific Development Squadron One (VXS-1). Aircraft positions were determined from kinematic GPS measurements in the aircraft relative to five base stations using differential interferometric techniques. Track spacing was set to 4 km over much of Afghanistan, but was increased to 8 km in the northern block of the survey area. Aircraft ground speed averaged between 300 and 380 knots, faster than ideal for high resolution gravity, but enabled approximately 113,000-km of data tracks to be flown in 220 flight hours, covering more than 330000 km2. In this presentation, we investigate the implications of the airborne gravity data for the tectonic development history of Afghanistan. Afghanistan is described as comprising three different platforms (Wheeler et al., 2005): 1) the north Afghanistan platform north of the Hari-Rud fault (HRF), a part of the Eurasian plate for 250-350 my; 2) the accreted terranes south of the HRF including low flats, formed as island arcs and fragments of continental and oceanic crust collided with the Eurasian plate during the closure of the Tethys Ocean in the past 250 my; and 3) the transpressional plate in the east, formed as the Indian plate moves northward since Cretaceous. The Bouguer anomaly map reveals elongated negative values along the east-west striking HRF, which seems to manifest different tectonic developmental histories across the boundary. Over the southern flats in the accreted terranes platform, the Bouguer anomaly map appears to show a continuation of alternating southwest-northeast trending highs and lows like those over the northern high

  3. Position and Acceleration for Airborne Gravity; the Impact of IMU Data

    NASA Astrophysics Data System (ADS)

    Preaux, S. A.; Diehl, T. M.; Holmes, S. A.; Weil, C.

    2012-12-01

    Accurate measurements in airborne gravimetry require high quality position and acceleration information in order to remove the effects of aircraft motion from the gravimeter signal. This study examines the impact of including Inertial Measurement Unit (IMU) data in position and acceleration determination for high altitude gravimetry as part of NGS's GRAV-D project. Processing with the IMU data provides a higher rate position solution that includes aircraft attitude information. The IMU can also be a source for velocity and acceleration information but these must be used with care as they contain the aircraft motion and the gravity signal. Results from the GRAV-D project's 2008 survey season in Alaska are used as a test case for this study. The use of a tightly coupled IMU+GPS solution reduced the survey RMS and standard deviation with respect to EGM08 by an average of 0.23 mGal per data track and improved the correlation between the data tracks and EGM08 by 0.04%. While these improvements appear small they represent approximately 10% of the discrepancy. Turbulent tracks showed the biggest improvement with localized improvements larger than 5 mGal in some cases. The measured gravity processed with either a GPS only position solution or a tightly coupled GPS+IMU position solution compared with EGM08 for one data track from the GRAV-D AK08 survey.

  4. Designing surveys for tests of gravity.

    PubMed

    Jain, Bhuvnesh

    2011-12-28

    Modified gravity theories may provide an alternative to dark energy to explain cosmic acceleration. We argue that the observational programme developed to test dark energy needs to be augmented to capture new tests of gravity on astrophysical scales. Several distinct signatures of gravity theories exist outside the 'linear' regime, especially owing to the screening mechanism that operates inside halos such as the Milky Way to ensure that gravity tests in the solar system are satisfied. This opens up several decades in length scale and classes of galaxies at low redshift that can be exploited by surveys. While theoretical work on models of gravity is in the early stages, we can already identify new regimes that cosmological surveys could target to test gravity. These include: (i) a small-scale component that focuses on the interior and vicinity of galaxy and cluster halos, (ii) spectroscopy of low-redshift galaxies, especially galaxies smaller than the Milky Way, in environments that range from voids to clusters, and (iii) a programme of combining lensing and dynamical information, from imaging and spectroscopic surveys, respectively, on the same (or statistically identical) sample of galaxies.

  5. Designing surveys for tests of gravity.

    PubMed

    Jain, Bhuvnesh

    2011-12-28

    Modified gravity theories may provide an alternative to dark energy to explain cosmic acceleration. We argue that the observational programme developed to test dark energy needs to be augmented to capture new tests of gravity on astrophysical scales. Several distinct signatures of gravity theories exist outside the 'linear' regime, especially owing to the screening mechanism that operates inside halos such as the Milky Way to ensure that gravity tests in the solar system are satisfied. This opens up several decades in length scale and classes of galaxies at low redshift that can be exploited by surveys. While theoretical work on models of gravity is in the early stages, we can already identify new regimes that cosmological surveys could target to test gravity. These include: (i) a small-scale component that focuses on the interior and vicinity of galaxy and cluster halos, (ii) spectroscopy of low-redshift galaxies, especially galaxies smaller than the Milky Way, in environments that range from voids to clusters, and (iii) a programme of combining lensing and dynamical information, from imaging and spectroscopic surveys, respectively, on the same (or statistically identical) sample of galaxies. PMID:22084295

  6. Ultra-sensitive electrostatic planar acceleration gradiometer for airborne geophysical surveys

    NASA Astrophysics Data System (ADS)

    Douch, Karim; Christophe, Bruno; Foulon, Bernard; Panet, Isabelle; Pajot-Métivier, Gwendoline; Diament, Michel

    2014-10-01

    We propose a new concept of gravity gradiometer, GREMLIT, for the determination of the spatial derivatives of gravitational acceleration during airborne surveys. The core of this instrument is the acceleration gradiometer composed of four ultra-sensitive electrostatic planar accelerometers, inheriting from technologies developed for the GRACE and GOCE satellite gravity missions. Data from these missions have greatly improved our knowledge of the Earth’s gravity field and its time variations. However, resolving wavelengths of a few 10 km or less, beyond the reach of the satellite resolution, is of utmost importance to study a number of crustal geophysical processes and geological structures. We first present the benefits for a new gravity gradiometer, then we describe the planar acceleration gradiometer, which put together with three orthogonal gyroscopes, constitutes the gravity gradiometer GREMLIT. The acceleration gradiometer enables measurement at one point of the horizontal spatial derivatives of the acceleration horizontal components. We explain the measurement principle and describe the computation of the gravity gradients along with the necessary ancillary measurements. From a detailed error budget analysis of the accelerometers, an expected spectral sensitivity below \\text{1E/}\\sqrt{\\text{Hz}} is found in the [10-3, 0.2] Hz measurement bandwidth. To maintain such performance in flight, we finally discuss the adaptation of the acceleration gradiometer to the turbulent airborne environment. To limit the saturation of the accelerometers, we propose to cancel the common-mode output of the acceleration gradiometer by integrating the instrument on a double-gimbal platform controlled by the common-mode. We demonstrate on a real case study that with such a solution, it is technically possible to prevent the saturation of the accelerometers at least 95% of the time and it is not damaging to the airborne survey.

  7. Consequences of flight height and line spacing on airborne (helicopter) gravity gradient resolution in the Great Sand Dunes National Park and Preserve, Colorado

    USGS Publications Warehouse

    Kass, M. Andy

    2013-01-01

    Line spacing and flight height are critical parameters in airborne gravity gradient surveys; the optimal trade-off between survey costs and desired resolution, however, is different for every situation. This article investigates the additional benefit of reducing the flight height and line spacing though a study of a survey conducted over the Great Sand Dunes National Park and Preserve, which is the highest-resolution public-domain airborne gravity gradient data set available, with overlapping high- and lower-resolution surveys. By using Fourier analysis and matched filtering, it is shown that while the lower-resolution survey delineates the target body, reducing the flight height from 80 m to 40 m and the line spacing from 100 m to 50 m improves the recoverable resolution even at basement depths.

  8. Television camera on RMS surveys insulation on Airborne Support Equipment

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The television camera on the end effector of the Canadian-built Remote Manipulator System (RMS) is seen surveying some of the insulation on the Airborne Support Equipment (ASE). Flight controllers called for the survey following the departure of the Advanced Communications Technology Satellite (ACTS) and its Transfer Orbit Stage (TOS).

  9. Inversion of Airborne Gravity Data over Subglacial Lakes in East Antarctica

    NASA Astrophysics Data System (ADS)

    Blankenship, D.

    2003-12-01

    The team of the University of Texas Institute for Geophysics (UTIG) has been performing airborne geophysical surveys in Antarctica since 1991. Over 260,000 line-km have been surveyed during nine field seasons. The UTIG airborne platform is a contracted DeHavilland Twin Otter instrumented with ice-penetrating radar, laser altimeter, magnetometer, and a gravimeter. The gravimeter utilized is a Bell Aerospace BGM-3 marine system, modified for airborne use, which provides measurements of vertical accelerations at 1 Hz, with verticality of the sensor maintained by a gyro-stabilized platform. The aerogeophysical surveys over subglacial Lake Concordia and Lake Vostok in East Antarctica were conducted by a team from UTIG over the course of the Antarctic field seasons. The region surrounding Lake Concordia was sampled by 6 profiles with a 10 km separation whereas the Lake Vostok survey block was 165 x 330 km with a line spacing of 7.5 km with 11.25 km and 22.5 km ties. 2D gravity inversion was performed for both lakes. The forward problem was solved using Talwani's algorithm for a 2D body of irregular shape. It is described by a non-linear equation between the body's shape and it's density contrast with surrounding rocks. The assumption was that the density contrast between ice/water and rock along the profile is constant. The densities of ice and water are close enough, so the ice and water of the lake can be considered as one body. For Lake Vostok the gravity data were inverted for 2-layered model, consisting of ice/water and sediment lying over dense bedrock. Inversion was performed by a conjugate gradient algorithm for several fixed values of density contrasts. The coordinates of layers' corners were chosen as model parameters. The model was constrained by the lake's boundaries and sub-ice topography, determined from radar sounding. Also, several pre-existing seismic soundings were used as `a priori' information incorporated into the model. The best agreement with

  10. Airborne Gravity Measurements using a Helicopter with Special Emphases on Delineating Local Gravity Anomalies Mainly for Detecting Active Seismic Faults (Invited)

    NASA Astrophysics Data System (ADS)

    Segawa, J.

    2010-12-01

    The first aerial gravity measurement in Japan started in 1998 using a Japanese airborne gravimeter ‘ Segawa-TKeiki airborne gravimeter Model FGA-1’. We lay emphasis on the measurement of detailed gravity structures at the land-to-sea border areas and mountainous areas. This is the reason why we use a helicopter and make surveys at low altitude and low speed. We have so far made measurement at twelve sites and the total flight amounts to 20,000km. The accuracy of measurement is 1.5 mgal and half-wavelength resolution is 1.5 km. The Japanese type gravimeter consists of a servo-accelerometer type gravity sensor, a horizontal platform controlled by an optical fiber gyro, GPS positioning system, and a data processing system. Helicopter movement has to be precisely monitored three-dimensionally to calculate the vehicle’s acceleration noises. The necessary accuracy of positioning of the vehicle must be better than 10 cm in positioning error. Our helicopter gravity measurement has a special target in Japan to investigate active seismic faults located across land-to-sea borderlines. In Japan, it is generally thought that gravity over most of the country has already been measured by the governmental surveys, leaving the land-sea border lines and mountainous zones unsurveyed as difficult-to-access areas. In addition the use of airplane or helicopter in Japan appeared disadvantageous because of the narrowness of the Japanese Islands. Under such situations the author thought there still remained a particular as well as unique need for aerial gravity measurement in Japan, i.e. the need for detailed and seamless knowledge of gravity structures across land-to-sea border lines to elucidate complicated crustal structures of the Japanese Islands as well as distribution of active seismic faults for disaster prevention. The results of gravity measurements we have conducted so far include those of 12 sites. In the following the brief logs of our measurements are listed. 1)April

  11. AIRBORNE INERTIAL SURVEYING USING LASER TRACKING AND PROFILING TECHNIQUES.

    USGS Publications Warehouse

    Cyran, Edward J.

    1986-01-01

    The U. S. Geological Survey through a contract with the Charles Stark Draper Laboratory has developed the Aerial Profiling of Terrain System. This is an airborne inertial surveying system designed to use a laser tracker to provide position and velocity updates, and a laser profiler to measure terrain elevations. The performance characteristics of the system are discussed with emphasis placed on the performance of the laser devices. The results of testing the system are summarized for both performance evaluation and applications.

  12. Alternative analysis of airborne laser data collected within conventional multi-parameter airborne geophysical surveys

    NASA Astrophysics Data System (ADS)

    Ahl, Andreas; Supper, R.; Motschka, K.; Schattauer, I.

    2010-05-01

    For the interpretation of airborne gamma-ray spectrometry as well as airborne electromagnetics it is of great importance to determine the distance between the geophysical sensor and the ground surface. Since radar altimeters do not penetrate vegetation, laser altimeters became popular in airborne geophysics over the past years. Currently the airborne geophysical platform of the Geological Survey of Austria (GBA) is equipped with a Riegl LD90-3800VHS-FLP high resolution laser altimeter, measuring the distances according to the first and the last reflected pulse. The goal of the presented study was to explore the possibilities of deriving additional information about the survey area from the laser data and to determine the accuracy of such results. On one hand the difference between the arrival time of the first and the last reflected pulse can be used to determine the height of the vegetation. This parameter is for example important for the correction of damping effects on airborne gamma-ray measurements caused by vegetation. Moreover especially for groundwater studies at catchment scale, this parameter can also be applied to support the spatial assessment of evapotranspiration. In combination with the altitude above geoid, determined by a GPS receiver, a rough digital elevation model of the survey area can be derived from the laser altimetry. Based on a data set from a survey area in the northern part of Austria, close to the border with the Czech Republic, the reliability of such a digital elevation model and the calculated vegetation height was tested. In this study a mean deviation of -1.4m, with a standard deviation of ±3.4m, between the digital elevation model from Upper Austria (25m spatial resolution) and the determined elevation model was determined. We also found an obvious correlation between the calculated vegetation heights greater 15m and the mapped forest published by the ‘Department of Forest Inventory' of the ‘Federal Forest Office' of Austria

  13. Investigating subglacial landscapes and crustal structure of the Gamburtsev Province in East Antarctica with the aid of new airborne gravity data

    NASA Astrophysics Data System (ADS)

    Jordan, T. A.; Ferraccioli, F.; Studinger, M.; Bell, R. E.; Damaske, D.; Elieff, S.; Finn, C.; Braaten, D. A.; Corr, H.

    2009-12-01

    The AGAP project was undertaken as part of the 2008\\09 field season and explored the Gamburtsev Subglacial Mountains (GSM) province in East Antarctica. AGAP collected >120, 000 line km of new airborne radar, aerogravity and aeromagnetic data. Here we focus on the airborne gravity part of the survey. The airborne gravity data were collected from two Twin Otters operating from remote field camps either side of Dome A. A high-resolution Sander Geophysics AIRGrav system was used for the first time in Antarctica and was mounted in the US plane. A more traditional L&R airborne gravity meter modified by ZLS was installed on the British Antarctic Survey aircraft. The AIRGrav system was flown in draped mode, which proved ideal for the simultaneous acquisition of radar and magnetic data, while the L&R system required flying along constant elevation survey blocks. The processed free-air gravity anomalies exhibit low cross-over errors of 1 mGal over the southern sector of the GSM, where the AIRGrav system was primarily used, and a spatial resolution of 3.5 km. Larger cross-over errors of 3.5 mGal and a coarser spatial resolution of 8 km characterise the northern part of the GSM and the adjacent Lambert Glacier, where the L&R meter was mainly flown. The merged free-air gravity anomaly grid primarily reflects the subglacial topography of the GSM province. The contrast between the Pensacola-Pole and Lambert Glacier basins and the rugged alpine-type relief of the GSM is clearly imaged. A dentritic system of subglacial valleys is mapped in the GSM, in good agreement with independent radar data. Inversion of the free-air gravity data assists in tracing the bedrock under several km-thick and fast-flowing crevassed ice of the Lambert Glacier. Using the ice thickness and bedrock topography data derived from airborne radar we compiled a new Bouguer anomaly map for the GSM province. The new gravity anomaly data can be used to estimate crustal thickness variations under the GSM and

  14. Low Gravity Guidance System for Airborne Microgravity Research

    NASA Technical Reports Server (NTRS)

    Rieke, W. J.; Emery, E. F.; Boyer, E. O.; Hegedus, C.; ODonoghue, D. P.

    1996-01-01

    Microgravity research techniques have been established to achieve a greater understanding of the role of gravity in the fundamentals of a variety of physical phenomena and material processing. One technique in use at the NASA Lewis Research Center involves flying Keplarian trajectories with a modified Lear Jet and DC-9 aircraft to achieve a highly accurate Microgravity environment by neutralizing accelerations in all three axis of the aircraft. The Low Gravity Guidance System (LGGS) assists the pilot and copilot in flying the trajectories by displaying the aircraft acceleration data in a graphical display format. The Low Gravity Guidance System is a microprocessor based system that acquires and displays the aircraft acceleration information. This information is presented using an electroluminescent display mounted over the pilot's instrument panel. The pilot can select the Microgravity range that is required for a given research event. This paper describes the characteristics, design, calibration and testing of the Low Gravity Guidance System Phase 3, significant lessons from earlier systems and the developmental work on future systems.

  15. Spectral combination of land-based, airborne, shipborne and altimeter-derived gravity values: examples in Taiwan and Tahiti

    NASA Astrophysics Data System (ADS)

    Hwang, Cheinway

    2016-04-01

    Taiwan and Tahiti are bordered by seas and are islands with mountain ranges up to 4000 m height. The gravity fields here are rough due to the geodynamic processes that create the islands. On and around the two islands, gravity data have been collected by land gravimeters in relative gravity networks (point-wise), by airborne and shipborne (along-track) methods and by transformations from sea surface heights (altimeter-derived). Typically, network-adjusted land gravity values have accuracies of few tens of micro gals and contain the full gravity spectrum. Airborne gravity values are obtained by filtering original one-HZ along-track gravity values collected at varying flight altitudes that are affected by aircraft dynamics, GPS positioning error and gravimeter error. At a 5000-m flight height, along-track airborne gravity has a typical spatial resolution of 4 km and an accuracy of few mgal. Shipborne gravity is similar to airborne gravity, but with higher spatial resolutions because of ship's lower speed. Altimeter-derived gravity has varying spatial resolutions and accuracies, depending on altimeter data, processing method and extent of waveform interference. Using the latest versions of Geosat/GM, ERS-1/GM, ENVISAT, Jason-1/GM, Cryosat-2 and SARAL altimeter data, one can achieve accuracies at few mgal. The synergy of the four kinds of gravity datasets is made by the band-limited least-squares collocation, which best integrates datasets of different accuracies and spatial resolutions. The method uses the best contributions from a DEM, a global gravity model, available gravity datasets to form an optimal gravity grid. We experiment with different optimal spherical harmonic degrees of EGM08 for use around the two islands. For Tahiti, the optimal degree is 1500. New high-resolution gravity and geoid grids are constructed for the two islands and can be used in future geophysical and geodetic studies.

  16. Basement interpretations from airborne magnetic and gravity data over the Lambert Rift region of East Antarctica

    NASA Astrophysics Data System (ADS)

    McLean, M. A.; Wilson, C. J. L.; Boger, S. D.; Betts, P. G.; Rawling, T. J.; Damaske, D.

    2009-06-01

    Geological exposures in the Lambert Rift region of East Antarctica comprise scattered coastal outcrops and inland nunataks sporadically protruding through the Antarctic ice sheet from Prydz Bay to the southernmost end of the Prince Charles Mountains. This study utilized airborne magnetic, gravity, and ice radar data to interpret the distribution and architecture of tectonic terranes that are largely buried beneath the thick ice sheet. Free-air and Bouguer gravity data are highly influenced by the subice and mantle topography, respectively. Gravity stripping facilitated the removal of the effect of ice and Moho, and the residual gravity data set thus obtained for the intermediate crustal level allowed a direct comparison with magnetic data. Interpretation of geophysical data also provided insight into the distribution and geometry of four tectonic blocks: namely, the Vestfold, Beaver, Mawson, and Gamburtsev domains. These tectonic domains are supported by surface observations such as rock descriptions, isotopic data sets, and structural mapping.

  17. Airborne gravity measurement over sea-ice: The western Weddel Sea

    SciTech Connect

    Brozena, J.; Peters, M. ); LaBrecque, J.; Bell, R.; Raymond, C. )

    1990-10-01

    An airborne gravity study of the western Weddel Sea, east of the Antarctic Peninsula, has shown that floating pack-ice provides a useful radar altimetric reference surface for altitude and vertical acceleration corrections surface for alititude and vertical acceleration corrections to airborne gravimetry. Airborne gravimetry provides an important alternative to satellite altimetry for the sea-ice covered regions of the world since satellite alimeters are not designed or intended to provide accurate geoidal heights in areas where significant sea-ice is present within the radar footprint. Errors in radar corrected airborne gravimetry are primarily sensitive to the variations in the second derivative of the sea-ice reference surface in the frequency pass-band of interest. With the exception of imbedded icebergs the second derivative of the pack-ice surface closely approximates that of the mean sea-level surface at wavelengths > 10-20 km. With the airborne method the percentage of ice coverage, the mixture of first and multi-year ice and the existence of leads and pressure ridges prove to be unimportant in determining gravity anomalies at scales of geophysical and geodetic interest, provided that the ice is floating and not grounded. In the Weddell study an analysis of 85 crosstrack miss-ties distributed over 25 data tracks yields an rms error of 2.2 mGals. Significant structural anomalies including the continental shelf and offsets and lineations interpreted as fracture zones recording the early spreading directions within the Weddell Sea are observed in the gravity map.

  18. Airborne-biogeochemical survey test-case results

    USGS Publications Warehouse

    Collins, William E.; Chang, Sheng-Huei; Raines, Gary L.; Canney, Frank C.; Ashley, Roger

    1980-01-01

    Airborne spectroradiometer surveys over several forest-covered sulfide bodies indicate that mineralization has affected the overlying vegetation; anomalous spectral reflectivity properties can be detected in the vegetation using appropriate remote-sensing interments and data-reduction techniques. Mineralization induces subtle changes in the shape of the chlorophyll a and b absorption spectrum between 550 and 750 nm. The observed spectral variations appear specifically to be on the wings of the broad red chlorophyll bars, centered at about 680 nm.

  19. Airborne infrared mineral mapping survey of Marysvale, Utah

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.

    1982-01-01

    Infrared spectroradiometer survey results from flights over the Marysvale, Utah district show that hydrothermal alteration mineralogy can be mapped using very rapid and effective airborne techniques. The system detects alteration mineral absorption band intensities in the infrared spectral region with high sensitivity. The higher resolution spectral features and high spectral differences characteristic of the various clay and carbonate minerals are also readily identified by the instrument allowing the mineralogy to be mapped as well as the mineralization intensity.

  20. Salinity surveys using an airborne microwave radiometer

    NASA Technical Reports Server (NTRS)

    Paris, J. F.; Droppleman, J. D.; Evans, D. E.

    1972-01-01

    The Barnes PRT-5 infrared radiometer and L-band channel of the multifrequency microwave radiometer are used to survey the distribution of surface water temperature and salinity. These remote sensors were flown repetitively in November 1971 over the outflow of the Mississippi River into the Gulf of Mexico. Data reduction parameters were determined through the use of flight data obtained over a known water area. With these parameters, the measured infrared and microwave radiances were analyzed in terms of the surface temperature and salinity.

  1. Inversion of Airborne Electromagnetic Survey Data, Styx River Area, Alaska

    NASA Astrophysics Data System (ADS)

    Kass, A.; Minsley, B. J.; Smith, B. D.; Burns, L.; Emond, A.

    2014-12-01

    A joint effort by the US Geological Survey (USGS) and the Alaska Division of Geological & Geophysical Surveys (DGGS) aims to add value to public domain airborne electromagnetic (AEM) data, collected in Alaska, through the application of newly developed advanced inversion methods to produce resistivity depth sections along flight lines. Derivative products are new geophysical data maps, interpretative profiles and displays. An important task of the new processing is to facilitate calibration or leveling between adjacent surveys flown with different systems in different years. The new approach will facilitate integration of the geophysical data in the interpretation and construction of geologic framework, resource evaluations and to geotechnical studies. Four helicopter airborne electromagnetic (AEM) surveys have been flown in the Styx River area by the DGGS; Styx River, Middle Styx, East Styx, and Farewell. The Styx River flown in 2008 and Middle Styx in flown 2013, cover an area of 2300 square kilometers. These data consist of frequency-domain DIGHEM V surveys which have been numerically processed and interpreted to yield a three-dimensional model of electrical resistivity. We describe the numerical interpretation methodology (inversion) in detail, from quality assessment to interpretation. We show two methods of inversion used in these datasets, deterministic and stochastic, and describe how we use these results to define calibration parameters and assess the quality of the datasets. We also describe the difficulties and procedures for combining datasets acquired at different times.

  2. Case Studies of Airborne Electromagnetic Survey of Volcanoes

    NASA Astrophysics Data System (ADS)

    Seto, S.; Takahara, T.; Kinoshita, A.; Mizuno, H.; Kawato, K.; Okumura, M.; Kageura, R.

    2015-12-01

    At Mt. Ontake in 1984 and Mt. Kurikoma in 2008, parts of the volcanoes collapsed and large-scale sediment disasters occurred. These events were unrelated to volcanic eruption. We conducted case studies using airborne electromagnetic surveys to investigate the slopes likely to cause landslides on such volcanoes. The surveys were conducted by using a helicopter carrying survey instruments; this method of non-contact investigation acquires specific electrical resistance data by electromagnetic induction. Airborne electromagnetic surveys were conducted of 15 active volcanoes where volcanic events could have serious social implications. These case studies extracted data showing only roughly the areas that were at risk of collapse, but this was the first time that such data on slopes likely to cause landslides and on estimated collapse depths were obtained. It remains necessary to find a method of extracting precise data on the slopes likely to induce landslides on each volcano. First, we collected the results of the volcano surveys and categorized the properties of the collapsed slopes as cap rock type, extended collapse type, or landslide type on the basis of the topography, geological information, and specific electrical resistivity structure. Second, we investigated whether the properties of each volcano were the same as these typified ones. We also defined a collapse range based mainly on the topography and geological properties and also on the collapse depth, which was based on the specific electrical resistivity structure. We revealed that we could use the defined collapse range and depth to estimate the sediment volume of the slopes that were likely to induce landslides. Several cases, including Mt. Hokkaido Komagatake, Mt. Azuma, Mt. Asama, and Mt. Ontake, will be introduced in this presentation.

  3. Global gravity survey by an orbiting gravity gradiometer

    NASA Technical Reports Server (NTRS)

    Paik, Ho Jung; Leung, Jurn-Sun; Morgan, Samuel H.; Parker, Joseph

    1988-01-01

    The scientific aims, design, and mission profile of the Superconducting Gravity Gradiometer Mission (SGGM), a NASA spacecraft mission proposed for the late 1990s, are discussed and illustrated with drawings and diagrams. SGGM would complement the two other planned gravimetry missions, GRM and Aristoteles, and would provide gravitational-field measurements with accuracy 2-3 mGal in 55 x 55-km blocks. The principal instruments are a (1) three-axis superconducting gravity gradiometer with intrinsic sensitivity 100 microeotvos/sq rt Hz, (2) a six-axis superconducting accelerometer with sensitivity 100 fg(E)/sq rt Hz linear and 10 prad/sec squared sq rt Hz angular, and (3) a six-axis shaker for active control of the platform. Consideration is given to the error budget and platform requirements, the orbit selection criteria, and the spacecraft design.

  4. Global gravity survey by an orbiting gravity gradiometer

    NASA Astrophysics Data System (ADS)

    Paik, Ho Jung; Leung, Jurn-Sun; Morgan, Samuel H.; Parker, Joseph

    1988-11-01

    The scientific aims, design, and mission profile of the Superconducting Gravity Gradiometer Mission (SGGM), a NASA spacecraft mission proposed for the late 1990s, are discussed and illustrated with drawings and diagrams. SGGM would complement the two other planned gravimetry missions, GRM and Aristoteles, and would provide gravitational-field measurements with accuracy 2-3 mGal in 55 x 55-km blocks. The principal instruments are a (1) three-axis superconducting gravity gradiometer with intrinsic sensitivity 100 microeotvos/sq rt Hz, (2) a six-axis superconducting accelerometer with sensitivity 100 fg(E)/sq rt Hz linear and 10 prad/sec squared sq rt Hz angular, and (3) a six-axis shaker for active control of the platform. Consideration is given to the error budget and platform requirements, the orbit selection criteria, and the spacecraft design.

  5. Gravity Survey of the Carson Sink - Data and Maps

    DOE Data Explorer

    Faulds, James E.

    2013-12-31

    A detailed gravity survey was carried out for the entire Carson Sink in western Nevada (Figure 1) through a subcontract to Zonge Engineering, Inc. The Carson Sink is a large composite basin containing three known, blind high‐temperature geothermal systems (Fallon Airbase, Stillwater, and Soda Lake). This area was chosen for a detailed gravity survey in order to characterize the gravity signature of the known geothermal systems and to identify other potential blind systems based on the structural setting indicated by the gravity data. Data: Data were acquired at approximately 400, 800, and 1600 meter intervals for a total of 1,243 stations. The project location and station location points are presented in Figure 14. The station distribution for this survey was designed to complete regional gravity coverage in the Carson Sink area without duplication of available public and private gravity coverage. Gravity data were acquired using a Scintrex CG‐5 gravimeter and a LaCoste and Romberg (L&R) Model‐G gravimeter. The CG‐5 gravity meter has a reading resolution of 0.001 milligals and a typical repeatability of less than 0.005 milligals. The L&R gravity meter has a reading resolution of 0.01 milligals and a typical repeatability of 0.02 milligals. The basic processing of gravimeter readings to calculate through to the Complete Bouguer Anomaly was made using the Gravity and Terrain Correction software version 7.1 for Oasis Montaj by Geosoft LTD. Results: The gravity survey of the Carson Sink yielded the following products. Project location and station location map (Figure 14). Complete Bouguer Anomaly @ 2.67 gm/cc reduction density. Gravity Complete Bouguer Anomaly at 2.50 g/cc Contour Map (Figure 15). Gravity Horizontal Gradient Magnitude Shaded Color Contour Map. Gravity 1st Vertical Derivative Color Contour Map. Interpreted Depth to Mesozoic Basement (Figure 16), incorporating drill‐hole intercept values. Preliminary Interpretation of Results: The Carson Sink

  6. Comparison of New Airborne Gravity Results and GRACE Anomalies in the Thwaites Glacier Catchment of the Amundsen Sea Embayment, West Antarctica

    NASA Astrophysics Data System (ADS)

    Diehl, T. M.; Holt, J. W.; Blankenship, D. D.; Richter, T. G.; Filina, I. Y.

    2005-12-01

    The West Antarctic Ice Sheet is a marine ice sheet of which 75% is resting on bedrock below sea level. This situation is highly unstable and as the climate warms, the potential for rapid discharge of the ice sheet grows. Examining the areas of the ice sheet that are most likely to react to changing climate is essential. The Amundsen Sea Embayment contains two of the most important outlet glaciers in West Antarctica: Thwaites and Pine Island Glaciers. These two glaciers have among the highest discharge velocities in West Antarctica and they lack large protective ice shelves, making them susceptible to warming ocean waters. The area is currently a target of interest for both GRACE and GLAS, as well as future land- and air-based surveys. To date, we have conducted the only large-scale geophysical survey over the catchment of Thwaites Glacier: an airborne survey completed during the austral summer 2004-2005. Over 43,500 line-kilometers of data were collected with a geophysical platform that included ice-penetrating radar, gravity, magnetics, laser and pressure altimetry, and GPS. Free-air gravity, in conjunction with magnetics and radar-derived subglacial topography, is capable of delineating microplate and rift boundaries as well as basin and volcano locations. A free-air gravity map of these structures helps ascertain the contribution of subglacial geology to the ice sheet's decay in the Thwaites Glacier catchment. The acquisition, reduction, and initial results of the airborne gravity survey will be presented and then compared to GRACE gravity anomalies. Extreme relief in ice surface elevation across the survey area necessitated short, smooth vertical altitude changes at survey block boundaries to maintain adequate flight altitude for the onboard ice-penetrating radar systems. Weather conditions sometimes required additional elevation changes or course corrections, producing significant aircraft motion during data acquisition. The impacts of these aircraft motions

  7. Automatic Searching Radioactive Sources by Airborne Radioactive Survey Using Multicopter

    NASA Astrophysics Data System (ADS)

    Rim, H.; Eun, S. B.; Kim, K.; Park, S.; Jung, H. K.

    2015-12-01

    In order to prepare emergency situation lost a dangerous radioelement source in advance and to search a radioactive source automatically, we develop airborne radioelement survey system by multicopter. This multicopter radioelement survey system consists of a small portable customized BGO (Bismuth Germanate Oxide) detector, video recording part, wireless connecting part to ground pilot, GPS, and several equipments for automatic flight. This system is possible to search flight by preprogramed lines. This radioactive detecting system are tested to find intentional hidden source, The performance of detecting a source is well proved with very low flight altitude in spite of depending on the magnitude of radioelement sources. The advantage of multicopter system, one of UAV (Unmanned Aerial Vehicle), is to avoid the potential of close access to a dangerous radioactive source by using fully automatic searching capability. In this paper, we introduce our multicopter system for detecting radioactive source and synthetic case history for demonstrating this system.

  8. A regional gravity survey of the Cuyuna Iron Range, Minnesota

    USGS Publications Warehouse

    Durfee, George Austin

    1957-01-01

    A regional gravity survey of the Cuyuna Iron Range, Minnesota, was conducted during the summer of 1955 by the U. S. Geological Survey. It was believed that gravity data would aid in the understanding of the major structures of the range. It was found that synclinal and steeply dipping structures produced positive gravity anomalies while anilclinal structures produced negative anomalies. This principle was noted in areas of well known geology and then applied to outlying areas of the district. The outstanding gravity feature is a narrow positive anomaly extending from south of Brainerd eastward through Aitkin, the axis of the anomaly being somewhat south of the South Range. This gives support to the theory that the Biwabik formation passes under the stratigraphically higher South Range member as a synclinal structure. However, this anomaly is also explained using one main iron formation and assuming an anticlinal structure between the North and South Ranges and a syncline between the South Range and Bay Lake. A large magnitude negative gravity anomaly north of Mille Lacs is postulated to result from an intrusive mass extending to the erosion surface. Aeromagnetics are used to strengthen the gravity interpretation. The need is realized for additional regional gravity coverage to the east of the area Included in this survey and a detailed gravity study of the area between the North and South Ranges.

  9. Hybrid gravity survey to search for submarine ore deposit

    NASA Astrophysics Data System (ADS)

    Araya, A.; Kanazawa, T.; Fujimoto, H.; Shinohara, M.; Yamada, T.; Mochizuki, K.; Iizasa, K.; Ishihara, T.; Omika, S.

    2011-12-01

    Along with seismic surveys, gravity survey is a useful method to profile the underground density structure. We propose a hybrid gravity survey using gravimeters and gravity gradiometers to detect submarine ore deposits as density anomalies by towing the instruments using an AUV (Autonomous Underwater Vehicle) or an ROV (Remotely Operated Vehicle). Gravimeters measure the regional density structure below the seafloor, whereas gravity gradiometers are sensitive to localized mass distribution. A gravity gradiometer comprises two accelerometers arranged with a vertical separation, and a gravity gradient can be obtained from the acceleration difference. Compared to gravimeters, gravity gradiometers are insensitive to common disturbances such as parallel acceleration, thermal drift, and apparent gravity effect (Eötvös effect). We made two accelerometers using astatic pendulums, and obtained common acceleration reduction more than two orders of magnitude. With these pendulums of 500-mm separation, resolution of 7E (=7x10^{-9}(1/s^2)), enough to detect a typical ore deposit buried 50m below the seafloor, was evaluated. During measurements using a submersible mobile object, instrument orientation is required to be controlled to keep verticality and to reduce centrifugal force associated with rotation of the instrument. Using a gyro and a tiltmeter, angular rotation was shown to be controlled within 0.001deg/s which corresponds to 0.3E in effective gravity gradient due to the centrifugal force. In this paper, target of this research, details of the instruments and their performance, and development for the submarine gravity survey using an AUV will be presented.

  10. Airborne laser altimetry survey of Glaciar Tyndall, Patagonia

    NASA Astrophysics Data System (ADS)

    Keller, Kristian; Casassa, Gino; Rivera, Andrés; Forsberg, Rene; Gundestrup, Niels

    2007-10-01

    The first airborne laser altimetry measurements of a glacier in South America are presented. Data were collected in November of 2001 over Glaciar Tyndall, Torres del Paine National Park, Chilean Patagonia, onboard a Twin Otter airplane of the Chilean Air Force. A laser scanner with a rotating polygon-mirror system together with an Inertial Navigation System (INS) were fixed to the floor of the aircraft, and used in combination with two dual-frequency GPS receivers. Together, the laser-INS-GPS system had a nominal accuracy of 30 cm after data processing. On November 23rd, a total of 235 km were flown over the ablation area of Glaciar Tyndall, with 5 longitudinal tracks with a mean swath width of 300 m, which results in a point spacing of approximately 2 m both along and across track. A digital elevation model (DEM) generated using the laser altimetry data was compared with a DEM produced from a 1975 map (1:50,000 scale — Instituto Geográfico Militar (IGM), Chile). A mean thinning of - 3.1 ± 1.0 m a - 1 was calculated for the ablation area of Glaciar Tyndall, with a maximum value of - 7.7 ± 1.0 m a - 1 at the calving front at 50 m a.s.l. and minimum values of between - 1.0 and - 2.0 ± 1.0 m a - 1 at altitudes close to the equilibrium line altitude (900 m a.s.l.). The thinning rates derived from the airborne survey were similar to the results obtained by means of ground survey carried out at ˜ 600 m of altitude on Glaciar Tyndall between 1975 and 2002, yielding a mean thinning of - 3.2 m a - 1 [Raymond, C., Neumann, T.A., Rignot, E., Echelmeyer, K.A., Rivera, A., Casassa, G., 2005. Retreat of Tyndall Glacier, Patagonia, over the last half century. Journal of Glaciology 173 (51), 239-247.]. A good agreement was also found between ice elevation changes measured with laser data and previous results obtained with Shuttle Radar Topography Mission (SRTM) data. We conclude that airborne laser altimetry is an effective means for accurately detecting glacier elevation

  11. Application of airborne thermal imagery to surveys of Pacific walrus

    USGS Publications Warehouse

    Burn, D.M.; Webber, M.A.; Udevitz, M.S.

    2006-01-01

    We conducted tests of airborne thermal imagery of Pacific walrus to determine if this technology can be used to detect walrus groups on sea ice and estimate the number of walruses present in each group. In April 2002 we collected thermal imagery of 37 walrus groups in the Bering Sea at spatial resolutions ranging from 1-4 m. We also collected high-resolution digital aerial photographs of the same groups. Walruses were considerably warmer than the background environment of ice, snow, and seawater and were easily detected in thermal imagery. We found a significant linear relation between walrus group size and the amount of heat measured by the thermal sensor at all 4 spatial resolutions tested. This relation can be used in a double-sampling framework to estimate total walrus numbers from a thermal survey of a sample of units within an area and photographs from a subsample of the thermally detected groups. Previous methods used in visual aerial surveys of Pacific walrus have sampled only a small percentage of available habitat, resulting in population estimates with low precision. Results of this study indicate that an aerial survey using a thermal sensor can cover as much as 4 times the area per hour of flight time with greater reliability than visual observation.

  12. Waste Isolation Pilot Plant (WIPP) site gravity survey and interpretation

    SciTech Connect

    Barrows, L.J.; Fett, J.D.

    1983-04-01

    A portion of the WIPP site has been extensively surveyed with high-precision gravity. The main survey (in T22S, R31E) covered a rectangular area 2 by 4-1/3 mi encompassing all of WIPP site Zone II and part of the disturbed zone to the north of the site. Stations were at 293-ft intervals along 13 north-south lines 880 ft apart. The data are considered accurate to within a few hundredths of a milligal. Long-wavelength gravity anomalies correlate well with seismic time structures on horizons below the Castile Formation. Both the gravity anomalies and the seismic time structures are interpreted as resulting from related density and velocity variations within the Ochoan Series. Shorter wavelength negative gravity anomalies are interpreted as resulting from bulk density alteration in the vicinity of karst conduits. The WIPP gravity survey was unable to resolve low-amplitude, long-wavelength anomalies that should result from the geologic structures within the disturbed zone. It did indicate the degree and character of karst development within the surveyed area.

  13. SURVEY OF CULTURABLE AIRBORNE BACTERIA AT FOUR DIVERSE LOCATIONS IN OREGON: URBAN, RURAL, FOREST, AND COASTAL

    EPA Science Inventory

    To determine the risks of microbial air pollution from microorganisms used for pesticides and bioremediation, or emanating from composting, fermentation tanks, or other agricultural and urban sources, airborne microbial levels must be evaluated. This study surveyed the atmospheri...

  14. Airborne and Ground Electrical Surveys for Subsurface Mapping of the Arbuckle Aquifer, Central Oklahoma

    NASA Astrophysics Data System (ADS)

    Smith, D.; Smith, B. D.; Blome, C. D.; Osborn, N.

    2008-12-01

    Airborne and ground electrical surveys have been conducted to map the subsurface hydrogeologic character of the Arbuckle-Simpson aquifer in south central Oklahoma. An understanding of the geologic framework and hydrogeologic characteristics is necessary to evaluate groundwater flow through the highly faulted, structurally complex, carbonate aquifer. Results from this research will further understanding of the aquifer and will assist in managing the water resources of the region. The major issues include water quality, the allocation of water rights, and the potential impacts of pumping on springs and stream. Four areas in the Hunton anticline area, with distinctly different geology, were flown with a frequency domain helicopter electromagnetic system (HEM) in March, 2007. Ground electrical studies include dc resistivity imaging and natural field audiomagnetotelluric (AMT), and magnetotelluric (MT) surveys. The HEM resistivity and total field magnetic survey was flown in four blocks, A through D, mostly with a line spacing of 400 m. Block A extends from the Chickasaw National Recreational Area (CHIC) to Mill Creek on the west side of the anticline. The surface geology of this block is mostly dolomitic limestone of the Arbuckle Group that is in fault contact with younger Paleozoic clastic rocks. The flight line spacing was 800 meters in the western half of the block and 400 meters in the eastern part. Airborne magnetic data indicate that the Sulphur fault bends south to merge with the Mill Creek fault which substantiates an earlier hypothesis first made from interpretation of gravity data. Block B, located on the north side of the anticline consists of mostly of Arbuckle and Simpson Group rocks. Block C, covering most of the Clarita horst on the east side of the anticline, consists of the Upper Ordovician to the Lower Pennsylvanian shales. Block D, which was flown to include a deep test well site at Spears ranch, consisted of eight lines spaced at 400 meters. The HEM

  15. The contribution of the GRAV-D airborne gravity to geoid determination in the Great Lakes region

    NASA Astrophysics Data System (ADS)

    Li, Xiaopeng; Crowley, John W.; Holmes, Simon A.; Wang, Yan-Ming

    2016-05-01

    The current official North American Vertical Datum of 1988 (NAVD 88) and the International Great Lakes Datum of 1985 (IGLD 85) will be replaced by a new geoid-based vertical datum in 2022. The Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project collects high-quality airborne gravity data to improve the quality of the gravitational model that underpins the geoid model. This paper validates the contribution of GRAV-D data in the Great Lakes region. Using the lake surface height measured by satellite altimetry as an independent data set, Global Gravity Models (GGMs) with/without the GRAV-D data are compared. The comparisons show that the improvement reaches decimeters over Lake Michigan where the historic gravity data have significant errors. Over all lakes, except Lake Erie, the GRAV-D data improve the accuracy of the gravitational model to 1-3 cm.

  16. Airborne radioactivity Survey of part of Saratoga NW quadrangle, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 133 square miles of Saratoga NW quadrangle, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  17. Gravity survey of the Mt. Toondina impact structure, South Australia

    NASA Technical Reports Server (NTRS)

    Plescia, J. B.; Shoemaker, E. M.; Shoemaker, C. S.

    1991-01-01

    The Mt. Toondina impact structure is located in northern South Australia, about 45 km south of the town of Oodnadatta. Only the central uplift is exposed. The outcrops at Mt. Toondina reveal a remarkable structural anomaly surrounded by a broad expanse of nearly flat-lying beds of the Bulldog Shale of Early Cretaceous age. A gravity survey was undertaken in 1989 to determine the diameter of the impact structure, define the form of the central uplift, and understand the local crustal structure. Data were collected along two orthogonal lines across the structure. In addition to the profiles, a significant number of measurements were made on and around the central uplift. The 1989 gravity data combined with 1963 gravity data and the seismic reflection data provide an excellent data base to interpret the subsurface structure of the Mt. Toondina feature.

  18. Detailed Gravity and Magnetic Survey of the Taylorsville Triassic Basin

    SciTech Connect

    Leftwich, John; Nowroozi, Ali, A.

    1999-10-01

    This work reports the progress on collecting existing gravity data in a rectangular area covering the Richmond and Taylorsville Basins and its vicinity. The area covers one-degree latitude and one degree longitude, starting at 37 North, 77 West and ending at 38 North, 78 West. Dr. David Daniels of the United State Geological Survey supplied us with more than 4900 Bouguer gravity anomalies in this area. The purpose of this report is to present the data in form of several maps and discuss its relation to the geology of the Triassic Basins and its vicinity. Johnson and others (1985) also presented a map of the Bouguer gravity anomaly of this area. However, their map covers a smaller area, and it is based on smaller number of observations.

  19. Gravity Survey of the Rye Patch KGRA, Rye Patch, Nevada

    NASA Astrophysics Data System (ADS)

    Mcdonald, M. R.; Gosnold, W. D.

    2011-12-01

    The Rye Patch Known Geothermal Resource Area (KGRA) is located in Pershing County Nevada on the west side of the Humboldt Range and east of the Rye Patch Reservoir approximately 200 km northeast of Reno, Nevada. Previous studies include an earlier gravity survey, 3-D seismic reflection, vertical seismic profiling (VSP) on a single well, 3-D seismic imaging, and a report of the integrated seismic studies. Recently, Presco Energy conducted an aeromagnetic survey and is currently in the process of applying 2-D VSP methods to target exploration and production wells at the site. These studies have indicated that geothermal fluid flow primarily occurs along faults and fractures and that two potential aquifers include a sandstone/siltstone member of the Triassic Natchez Pass Formation and a karst zone that occurs at the interface between Mesozoic limestone and Tertiary volcanics. We hypothesized that addition of a high-resolution gravity survey would better define the locations, trends, lengths, and dip angles of faults and possible solution cavity features. The gravity survey encompassed an area of approximately 78 km2 (30 mi2) within the boundary of the KGRA along with portions of 8 sections directly to the west and 8 sections directly to the east. The survey included 203 stations that were spaced at 400 m intervals. The simple Bouguer anomaly patterns were coincident with elevation, and those patterns remained after terrain corrections were performed. To remove this signal, the data were further processed using wave-length (bandpass) filtering techniques. The results of the filtering and comparison with the recent aeromagnetic survey indicate that the location and trend of major fault systems can be identified using this technique. Dip angles can be inferred by the anomaly contour gradients. By further reductions in the bandpass window, other features such as possible karst solution channels may also be recognizable. Drilling or other geophysical methods such as a

  20. Crustal structure beneath the Paleozoic Parnaíba Basin revealed by airborne gravity and magnetic data, Brazil

    USGS Publications Warehouse

    de Castroa, David L.; Fuck, Reinhardt A.; Phillips, Jeffrey D. Phillips; Vidotti, Roberta M.; Bezerra, Francisco H.R.; Dantas, Elton L.

    2014-01-01

    The Parnaíba Basin is a large Paleozoic syneclise in northeastern Brazil underlain by Precambrian crystalline basement, which comprises a complex lithostructural and tectonic framework formed during the Neoproterozoic–Eopaleozoic Brasiliano–Pan African orogenic collage. A sag basin up to 3.5 km thick and 1000 km long formed after the collage. The lithologic composition, structure, and role in the basin evolution of the underlying basement are the focus of this study. Airborne gravity and magnetic data were modeled to reveal the general crustal structure underneath the Parnaíba Basin. Results indicate that gravity and magnetic signatures delineate the main boundaries and structural trends of three cratonic areas and surrounding Neoproterozoic fold belts in the basement. Triangular-shaped basement inliers are geophysically defined in the central region of this continental-scale Neoproterozoic convergence zone. A 3-D gravity inversion constrained by seismological data reveals that basement inliers exhibit a 36–40.5 km deep crustal root, with borders defined by a high-density and thinner crust. Forward modeling of gravity and magnetic data indicates that lateral boundaries between crustal units are limited by Brasiliano shear zones, representing lithospheric sutures of the Amazonian and São Francisco Cratons, Tocantins Province and Parnaíba Block. In addition, coincident residual gravity, residual magnetic, and pseudo-gravity lows indicate two complex systems of Eopaleozoic rifts related to the initial phase of the sag deposition, which follow basement trends in several directions.

  1. Detailed Gravity and Magnetic Survey of the Taylorsville Triassic Basin

    SciTech Connect

    Ali A. Nowroozi; John Leftwich

    1997-12-31

    Our research to date has involved the Interpretation of the Bouguer Gravity Anomaly Associated with the Richmond and Taylorsville Triassic Basins and its Vicinity. Continental rift basins around the world contain about 5% of the earth's sedimentary layers and produce about 20% of the total hydrocarbon production of the world (Ziegler (1983). Nearly 30 large basins of this type are reported by Manspeizer and Cousminer (1988) in eastern North America and northwestern Africa. There are eleven exposed basins of this type in the state of Virginia, from which nine are totally and two partially within the state's border. The number of unexposed basin's is not known. Exploration and drilling have been hampered largely because surface data are insufficient for even evaluation of those basins which are partly or completely exposed in the Piedmont Province. Generation of data through random exploratory drilling and seismic exploration is much too expensive and, therefore, these methods have not been widely used. In order to remedy this situation, we have used a geophysical method and completed a detailed and dense ground gravity surveys of the Richmond (Nowroozi and Wong, 1989, Daniels and Nowroozi, 1987). In this work we report our progress on collecting existing gravity data in a rectangular area covering the Richmond and Taylorsville Basins and its vicinity. The area covers one degree latitude and one degree longitude, starting at 37 North, 77 West and ending at 38 North, 78 West. Dr. David Daniels of the United State Geological Survey supplied us with more than 4900 Bouguer gravity anomalies in this area. The purpose of this progress report is to present the data in form of several maps and discuss its relation to the geology of the Triassic Basins and its vicinity. Johnson and others (1985) also presented a map of the Bouguer gravity anomaly of this area. However, their map covers a smaller area, and it is based on smaller number of observations.

  2. Gravity survey of the southwestern part of the sourthern Utah geothermal belt

    SciTech Connect

    Green, R.T.; Cook, K.L.

    1981-03-01

    A gravity survey covering an area of 6200 km/sup 2/ was made over the southwestern part of the southern Utah geothermal belt. The objective of the gravity survey is to delineate the geologic structures and assist in the understanding of the geothermal potential of the area. A total of 726 new gravity stations together with 205 existing gravity stations, are reduced to give: (1) a complete Bouguer gravity anomaly map, and (2) a fourth-order residual gravity anomaly map; both maps have a 2-mgal contour interval. The complete Bouguer gravity anomaly map shows an east-trending regional gravity belt with a total relief of about 70 mgal which crosses the central portion of the survey area. The gravity belt is attributed to a crustal lateral density variation of 0.1 gm/cc from a depth of 5 to 15 km.

  3. Integrating stations from the North America Gravity Database into a local GPS-based land gravity survey

    USGS Publications Warehouse

    Shoberg, Thomas G.; Stoddard, Paul R.

    2013-01-01

    The ability to augment local gravity surveys with additional gravity stations from easily accessible national databases can greatly increase the areal coverage and spatial resolution of a survey. It is, however, necessary to integrate such data seamlessly with the local survey. One challenge to overcome in integrating data from national databases is that these data are typically of unknown quality. This study presents a procedure for the evaluation and seamless integration of gravity data of unknown quality from a national database with data from a local Global Positioning System (GPS)-based survey. The starting components include the latitude, longitude, elevation and observed gravity at each station location. Interpolated surfaces of the complete Bouguer anomaly are used as a means of quality control and comparison. The result is an integrated dataset of varying quality with many stations having GPS accuracy and other reliable stations of unknown origin, yielding a wider coverage and greater spatial resolution than either survey alone.

  4. Airborne radioactivity surveys of parts of Savery SW and Savery SE quadrangles, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 222 square miles of Savery SW and Savery SE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  5. Airborne radioactivity survey of parts of Savery NW and Savery NE quadrangles, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 266 square miles of Savery NW and Savery NE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  6. Alternative Gravity Rotation Curves for the LITTLE THINGS Survey

    NASA Astrophysics Data System (ADS)

    Stulge, Modestas; Stefanski, Brian; Dentico, Jeremy; O'Brien, James; Gay, Joseph; Moss, Robert; Young, Bryan; Smith, Adam

    2016-03-01

    Galactic rotation curves have proven to be the testing ground for dark matter bounds in spiral galaxies of all morphologies. Dwarf Galaxies serve as an increasingly interesting testing ground of rotation curve dynamics due to their increased stellar formation and typically rising rotation curve. These galaxies usually are not dominated by typical stellar structure and mostly terminate at small radial distances. This, coupled with the fact that Cold Dark Matter theories such as NFW (ΛCDM) struggle with the universality of galactic rotation curves, allow for exclusive features of alternative gravitational models to be analyzed. Recently, the THINGS (The HI Nearby Galactic Survey) has been extended to include a sample of 25 dwarf galaxies now known as the LITTLE THINGS Survey. Here, we present a thorough application of alternative gravitational models to the LITTLE THINGS survey, specifically focusing on MOND and Conformal Gravity. An analysis and discussion of the results of the fitting procedure of the two alternative gravitational models are explored. We posit here that both the Conformal Gravity and MOND can provide an accurate description of the galactic dynamics without the need for copious dark matter.

  7. Airborne electromagnetic and magnetic survey data of the Paradox and San Luis Valleys, Colorado

    USGS Publications Warehouse

    Ball, Lyndsay B.; Bloss, Benjamin R.; Bedrosian, Paul A.; Grauch, V.J.S.; Smith, Bruce D.

    2015-01-01

    In October 2011, the U.S. Geological Survey (USGS) contracted airborne magnetic and electromagnetic surveys of the Paradox and San Luis Valleys in southern Colorado, United States. These airborne geophysical surveys provide high-resolution and spatially comprehensive datasets characterizing the resistivity structure of the shallow subsurface of each survey region, accompanied by magnetic-field information over matching areas. These data were collected to provide insight into the distribution of groundwater brine in the Paradox Valley, the extent of clay aquitards in the San Luis Valley, and to improve our understanding of the geologic framework for both regions. This report describes these contracted surveys and releases digital data supplied under contract to the USGS.

  8. Development of a network RTK positioning and gravity-surveying application with gravity correction using a smartphone.

    PubMed

    Kim, Jinsoo; Lee, Youngcheol; Cha, Sungyeoul; Choi, Chuluong; Lee, Seongkyu

    2013-07-12

    This paper proposes a smartphone-based network real-time kinematic (RTK) positioning and gravity-surveying application (app) that allows semi-real-time measurements using the built-in Bluetooth features of the smartphone and a third-generation or long-term evolution wireless device. The app was implemented on a single smartphone by integrating a global navigation satellite system (GNSS) controller, a laptop, and a field-note writing tool. The observation devices (i.e., a GNSS receiver and relative gravimeter) functioned independently of this system. The app included a gravity module, which converted the measured relative gravity reading into an absolute gravity value according to tides; meter height; instrument drift correction; and network adjustments. The semi-real-time features of this app allowed data to be shared easily with other researchers. Moreover, the proposed smartphone-based gravity-survey app was easily adaptable to various locations and rough terrain due to its compact size.

  9. Survey of subsurface geophysical exploration technologies adaptable to an airborne platform

    SciTech Connect

    Taylor, K.A.

    1992-12-01

    This report has been prepared by the US Department of Energy (DOE) as part of a Research Development Demonstration Testing and Evaluation (RDDT E) project by EG G Energy Measurement's (EG G/EM) Remote Sensing Laboratory. It examines geophysical detection techniques which may be used in Environmental Restoration/Waste Management (ER/WM) surveys to locate buried waste, waste containers, potential waste migratory paths, and aquifer depths. Because of the Remote Sensing Laboratory's unique survey capabilities, only those technologies which have been adapted or are capable of being adapted to an airborne platform were studied. This survey describes several of the available subsurface survey technologies and discusses the basic capabilities of each: the target detectability, required geologic conditions, and associated survey methods. Because the airborne capabilities of these survey techniques have not been fully developed, the chapters deal mostly with the ground-based capabilities of each of the technologies, with reference made to the airborne capabilities where applicable. The information about each survey technique came from various contractors whose companies employ these specific technologies. EG G/EM cannot guarantee or verify the accuracy of the contractor information; however, the data given is an indication of the technologies that are available.

  10. Survey of subsurface geophysical exploration technologies adaptable to an airborne platform

    SciTech Connect

    Taylor, K.A.

    1992-12-01

    This report has been prepared by the US Department of Energy (DOE) as part of a Research Development Demonstration Testing and Evaluation (RDDT&E) project by EG&G Energy Measurement`s (EG&G/EM) Remote Sensing Laboratory. It examines geophysical detection techniques which may be used in Environmental Restoration/Waste Management (ER/WM) surveys to locate buried waste, waste containers, potential waste migratory paths, and aquifer depths. Because of the Remote Sensing Laboratory`s unique survey capabilities, only those technologies which have been adapted or are capable of being adapted to an airborne platform were studied. This survey describes several of the available subsurface survey technologies and discusses the basic capabilities of each: the target detectability, required geologic conditions, and associated survey methods. Because the airborne capabilities of these survey techniques have not been fully developed, the chapters deal mostly with the ground-based capabilities of each of the technologies, with reference made to the airborne capabilities where applicable. The information about each survey technique came from various contractors whose companies employ these specific technologies. EG&G/EM cannot guarantee or verify the accuracy of the contractor information; however, the data given is an indication of the technologies that are available.

  11. Airborne radioactivity survey in the vicinity of Grants, McKinley and Valencia Counties, New Mexico

    USGS Publications Warehouse

    Stead, Frank W.

    1951-01-01

    An airborne radioactivity survey in the vicinity of Grants, New Mexico, was made on May 28. 1951; aeromagnetic measurements were made concurrently with the radioactivity measurements. Several radioactivity anomalies were noted in conjunction with negative magnetic anomalies; this association is unusual and may reflect a genetic relationship between the uranium mineralization and the geologic structure causing the negative magnetic effect. Further investigation of the vicinity of the anomalies near the Haystack area, including ground magnetometer survey, seems warranted.

  12. Geophex Airborne Unmanned Survey System (GAUSS). Topical report, October 1993--March 1995

    SciTech Connect

    1995-03-01

    The objectives of the project are to construct a geophysical sensor system based on a remotely operated model helicopter (ROH) and to evaluate the efficacy of the system for characterization of hazardous environmental sites. Geophex Airborne Unmanned Survey System (GAUSS) is a geophysical survey system that uses a ROH as the survey vehicle. We have selected the ROH because of its advantages over fixed wing and ground based vehicles. Lower air speed and superior maneuverability of the ROH make it better suited for geophysical surveys than a fixed wing model aircraft. The ROH can fly close to the ground, allowing detection of weak or subtle anomalies. Unlike ground based vehicles, the ROH can traverse difficult terrain while providing a stable sensor platform. ROH does not touch the ground during the course of a survey and is capable of functioning over water and surf zones. The ROH has been successfully used in the motion picture industry and by geology companies for payload bearing applications. The only constraint to use of the airborne system is that the ROH must remain visible to the pilot. Obstructed areas within a site can be characterized by relocating the base station to alternate positions. GAUSS consists of a ROH with radio controller, a data acquisition and processing (DAP) system, and lightweight digital sensor systems. The objective of our Phase I research was to develop a DAP and sensors suitable for ROH operation. We have constructed these subsystems and integrated them to produce an automated, hand-held geophysical surveying system, referred to as the ``pre-prototype``. We have performed test surveys with the pre-prototype to determine the functionality of the and DAP and sensor subsystems and their suitability for airborne application. The objective of the Phase II effort will be to modify the existing subsystems and integrate them into an airborne prototype. Efficacy of the prototype for geophysical survey of hazardous sites will then be determined.

  13. An interpretation of the 1997 airborne electromagnetic (AEM) survey, Fort Huachuca vicinity, Cochise County, Arizona

    USGS Publications Warehouse

    Bultman, M.W.; Gettings, M.E.; Wynn, Jeff

    1999-01-01

    Executive Summary -- In March of 1997, an airborne electromagnetic (AEM) survey of the Fort Huachuca Military Reservation and immediate surrounds (location map, http://geopubs.wr.usgs.gov/open-file/of99-007-b/index.jpg) was conducted. This survey was sponsored by the U.S. Army and contracted through the Geologic Division of the U.S. Geological Survey (USGS). Data were gathered by Geoterrex-Dighem Ltd. of Ottawa, Canada. The survey aircraft is surrounded by a coil through which a large current pulse is passed. This pulse induces currents in the Earth which are recorded by a set of three mutually perpendicular coils towed in a 'bird' about 100 m behind and below the aircraft. The bird also records the Earth's magnetic field. The system samples the Earth response to the electromagnetic pulse about every 16 m along the aircraft flight path. For this survey, the bulk of the flightpaths were spaced about 400 m apart and oriented in a northeast-southwest direction extending from bedrock over the Huachuca Mountains to bedrock over the Tombstone Hills. A preliminary report on the unprocessed data collected in the field was delivered to the U.S. Army by USGS in July 1997 (USGS Open-File Report 97?457). The final data were delivered in March, 1998 by the contractor to USGS and thence to the U.S. Army. The present report represents the final interpretive report from USGS. The objectives of the survey were to: 1) define the structure of the San Pedro basin in the Sierra Vista-Fort Huachuca-Huachuca City area, including the depth and shape of the basin, and to delineate large faults that may be active within the basin fill and therefore important in the hydrologic regime; 2) define near surface and subsurface areas that contain a large volume fraction of silt and clay in the basin fill and which both reduce the volume of available storage for water and reduce the permeability of the aquifer; and 3) to evaluate the use of the time domain electromagnetic method in the southwest

  14. Inference of lithologic distributions in an alluvial aquifer using airborne transient electromagnetic surveys

    USGS Publications Warehouse

    Dickinson, Jesse E.; Pool, D.R.; Groom, R.W.; Davis, L.J.

    2010-01-01

    An airborne transient electromagnetic (TEM) survey was completed in the Upper San Pedro Basin in southeastern Arizona to map resistivity distributions within the alluvial aquifer. This investigation evaluated the utility of 1D vertical resistivity models of the TEM data to infer lithologic distributions in an alluvial aquifer. Comparisons of the resistivity values and layers in the 1D resistivity models of airborne TEM data to 1D resistivity models of ground TEM data, borehole resistivity logs, and lithologic descriptions in drill logs indicated that the airborne TEM identified thick conductive fine-grained sediments that result in semiconfined groundwater conditions. One-dimensional models of ground-based TEM surveys and subsurface lithology at three sites were used to determine starting models and constraints to invert airborne TEM data using a constrained Marquardt-styleunderparameterized method. A maximum structural resolution of six layers underlain by a half-space was determined from the resistivity structure of the 1D models of the ground TEM data. The 1D resistivity models of the airborne TEM data compared well with the control data to depths of approximately 100 m in areas of thick conductive silt and clay and to depths of 200 m in areas of resistive sand and gravel. Comparison of a 3D interpolation of the 1D resistivity models to drill logs indicated resistive (mean of 65 ohm-m ) coarse-grained sediments along basin margins and conductive (mean of 8 ohm-m ) fine-grained sediments at the basin center. Extents of hydrologically significant thick silt and clay were well mapped by the 1D resistivity models of airborne TEM data. Areas of uncertain lithology remain below conductive fine-grained sediments where the 1D resistivity structure is not resolved: in areas where multiple lithologies have similar resistivity values and in areas of high salinity.

  15. Determining a pre-mining radiological baseline from historic airborne gamma surveys: a case study.

    PubMed

    Bollhöfer, Andreas; Beraldo, Annamarie; Pfitzner, Kirrilly; Esparon, Andrew; Doering, Che

    2014-01-15

    Knowing the baseline level of radioactivity in areas naturally enriched in radionuclides is important in the uranium mining context to assess radiation doses to humans and the environment both during and after mining. This information is particularly useful in rehabilitation planning and developing closure criteria for uranium mines as only radiation doses additional to the natural background are usually considered 'controllable' for radiation protection purposes. In this case study we have tested whether the method of contemporary groundtruthing of a historic airborne gamma survey could be used to determine the pre-mining radiological conditions at the Ranger mine in northern Australia. The airborne gamma survey was flown in 1976 before mining started and groundtruthed using ground gamma dose rate measurements made between 2007 and 2009 at an undisturbed area naturally enriched in uranium (Anomaly 2) located nearby the Ranger mine. Measurements of (226)Ra soil activity concentration and (222)Rn exhalation flux density at Anomaly 2 were made concurrent with the ground gamma dose rate measurements. Algorithms were developed to upscale the ground gamma data to the same spatial resolution as the historic airborne gamma survey data using a geographic information system, allowing comparison of the datasets. Linear correlation models were developed to estimate the pre-mining gamma dose rates, (226)Ra soil activity concentrations, and (222)Rn exhalation flux densities at selected areas in the greater Ranger region. The modelled levels agreed with measurements made at the Ranger Orebodies 1 and 3 before mining started, and at environmental sites in the region. The conclusion is that our approach can be used to determine baseline radiation levels, and provide a benchmark for rehabilitation of uranium mines or industrial sites where historical airborne gamma survey data are available and an undisturbed radiological analogue exists to groundtruth the data.

  16. Investigation of coastal areas in Northern Germany using airborne geophysical surveys

    NASA Astrophysics Data System (ADS)

    Miensopust, Marion; Siemon, Bernhard; Wiederhold, Helga; Steuer, Annika; Ibs-von Seht, Malte; Voß, Wolfgang; Meyer, Uwe

    2014-05-01

    Since 2000, the German Federal Institute for Geosciences and Natural Resources (BGR) carried out several airborne geophysical surveys in Northern Germany to investigate the coastal areas of the North Sea and some of the North and East Frisian Islands. Several of those surveys were conducted in cooperation with the Leibniz Institute for Applied Geophysics (LIAG). Two helicopter-borne geophysical systems were used, namely the BGR system, which collects simultaneously frequency-domain electromagnetic, magnetic and radiometric data, and the SkyTEM system, a time-domain electromagnetic system developed by the University of Aarhus. Airborne geophysical surveys enable to investigate huge areas almost completely with high lateral resolution in a relatively short time at economic cost. In general, the results can support geological and hydrogeological mapping. Of particular importance are the airborne electromagnetic results, as the surveyed parameter - the electrical conductivity - depends on both lithology and groundwater status. Therefore, they can reveal buried valleys and the distribution of sandy and clayey sediments as well as salinization zones and fresh-water occurrences. The often simultaneously recorded magnetic and radiometric data support the electromagnetic results. Lateral changes of Quaternary and Tertiary sediments (shallow source - several tens of metres) as well as evidences of the North German Basin (deep source - several kilometres) are revealed by the magnetic results. The radiometric data indicate the various mineral compositions of the soil sediments. This BGR/LIAG project aims to build up a geophysics data base (http://geophysics-database.de/) which contains all airborne geophysical data sets. However, the more significant effort is to create a reference data set as basis for monitoring climate or man-made induced changes of the salt-water/fresh-water interface at the German North Sea coast. The significance of problems for groundwater extraction

  17. Basis and methods of NASA airborne topographic mapper lidar surveys for coastal studies

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Sallenger, Asbury H.; Krabill, William B.; Swift, Robert N.

    2002-01-01

    This paper provides an overview of the basic principles of airborne laser altimetry for surveys of coastal topography, and describes the methods used in the acquisition and processing of NASA Airborne Topographic Mapper (ATM) surveys that cover much of the conterminous US coastline. This form of remote sensing, also known as "topographic lidar", has undergone extremely rapid development during the last two decades, and has the potential to contribute within a wide range of coastal scientific investigations. Various airborne laser surveying (ALS) applications that are relevant to coastal studies are being pursued by researchers in a range of Earth science disciplines. Examples include the mapping of "bald earth" land surfaces below even moderately dense vegetation in studies of geologic framework and hydrology, and determination of the vegetation canopy structure, a key variable in mapping wildlife habitats. ALS has also proven to be an excellent method for the regional mapping of geomorphic change along barrier island beaches and other sandy coasts due to storms or long-term sedimentary processes. Coastal scientists are adopting ALS as a basic method in the study of an array of additional coastal topics. ALS can provide useful information in the analysis of shoreline change, the prediction and assessment of landslides along seacliffs and headlands, examination of subsidence causing coastal land loss, and in predicting storm surge and tsunami inundation.

  18. Airborne geophysical surveys conducted in western Nebraska, 2010: contractor reports and data

    USGS Publications Warehouse

    ,

    2014-01-01

    This report contains three contractor reports and data files for an airborne electromagnetic survey flown from June 28 to July 7, 2010. The first report; “SkyTEM Survey: Nebraska, USA, Data” describes data aquisition and processing from a time-domain electromagnetic and magnetic survey performed by SkyTEM Canada, Inc. (the North American SkyTEM subsidiary), in western Nebraska, USA. Digital data for this report are given in Appendix 1. The airborne geophysical data from the SkyTEM survey subsequently were processed and inverted by Aarhus Geophysics ApS, Aarhus, Denmark, to produce resistivity depth sections along each flight line. The result of that processing is described in two reports presented in Appendix 2, “Processing and inversion of SkyTEM data from USGS Area UTM–13” and “Processing and inversion of SkyTEM data from USGS Area UTM–14.” Funding for these surveys was provided by the North Platte Natural Resources District, the South Platte Natural Resources District, and the Twin Platte Natural Resources District, in Scottsbluff, Sidney, and North Platte, Nebraska, respectively. Any additional information concerning the geophysical data may be obtained from the U.S. Geological Survey Crustal Geophysics and Geochemistry Science Center, Denver Colorado.

  19. A survey of respirators usage for airborne chemicals in Korea.

    PubMed

    Han, Don-Hee; Kang, Min-Sun

    2009-10-01

    A questionnaire survey was undertaken to identify the current status of respirator usage in manufacturing work environments subject to gas/vapor chemicals exposure in Korea and to suggest improvements to enhance the effectiveness of respirator usage. The number of target companies included 17 big companies, 110 small & mid-size companies, and 5 foreign companies, and the number of respondents included 601 workers and 69 persons in charge of respirators (PCR). The results explained clearly that respirator programs in practice were extremely poor in small & mid-sized companies. The findings indicated that the selection of respirators was not appropriate. Quarter mask including filtering facepiece was the most common facepiece form for respirator and was worn by sixty-four percent. Not a little proportion of respondents (33%) complained about the fit: faceseal leakage between the face and facepiece. A filtering facepiece with carbon fiber filter was used as a substitution for a gas/vapor respirator. Another result was that the PCR respondents' perception of the administration of respirators was very low. The results of this survey suggest that regal enforcement of respiratory protection programs should be established in Korea. On the basis of these findings, respiratory protection programs should include respirator selection, maintenance, training, and fit testing. PMID:19834267

  20. A survey of respirators usage for airborne chemicals in Korea.

    PubMed

    Han, Don-Hee; Kang, Min-Sun

    2009-10-01

    A questionnaire survey was undertaken to identify the current status of respirator usage in manufacturing work environments subject to gas/vapor chemicals exposure in Korea and to suggest improvements to enhance the effectiveness of respirator usage. The number of target companies included 17 big companies, 110 small & mid-size companies, and 5 foreign companies, and the number of respondents included 601 workers and 69 persons in charge of respirators (PCR). The results explained clearly that respirator programs in practice were extremely poor in small & mid-sized companies. The findings indicated that the selection of respirators was not appropriate. Quarter mask including filtering facepiece was the most common facepiece form for respirator and was worn by sixty-four percent. Not a little proportion of respondents (33%) complained about the fit: faceseal leakage between the face and facepiece. A filtering facepiece with carbon fiber filter was used as a substitution for a gas/vapor respirator. Another result was that the PCR respondents' perception of the administration of respirators was very low. The results of this survey suggest that regal enforcement of respiratory protection programs should be established in Korea. On the basis of these findings, respiratory protection programs should include respirator selection, maintenance, training, and fit testing.

  1. A comparison of the use of sodium iodide and lanthanum bromide scintillation crystals for airborne surveys

    NASA Astrophysics Data System (ADS)

    Bailey, Derek M.

    The Environmental Protection Agency (EPA) Aerial Spectral Environmental Collection Technology (ASPECT) program performs aerial radiological and chemical characterization of geographical regions of interest. Airborne surveys are performed to characterize environmental radionuclide content, for mineral exploration, as well as for emergency scenarios such as major releases or lost sources. Two radiological detection systems are used by the ASPECT team for gamma-ray detection and characterization: lanthanum bromide [LaBr 3(Ce)] and sodium iodide [NaI(Tl)] scintillation systems. An aerial survey of a uranium mine in the western United States was performed using both NaI(Tl) and LaBr3(Ce) detection systems. Analyses of the survey data were performed with RadAssist software and applying International Atomic Energy Agency (IAEA) airborne gamma ray mapping guidelines. The data for the survey were corrected for cross-over, which is spectral interference from higher energy photons as a result of Compton scattering, height attenuation, cosmic ray contribution to signal, and Radon contribution to signal. Two radiation survey contours were generated from each discrete data set. Based on analysis of the uranium mine survey results, LaBr3(Ce) produced a product comparable to that of NaI(Tl). The LaBr3(Ce) detection system contained 1/16th the scintillating volume and had a total system weight that was 1/4th that of the NaI(Tl) system. LaBr3(Ce) demonstrated a clear advantage over NaI(Tl) detectors in system mobility, and weight factors in airborne gamma ray spectroscopy.

  2. Marine magnetic survey and onshore gravity and magnetic survey, San Pablo Bay, northern California

    USGS Publications Warehouse

    Ponce, David A.; Denton, Kevin M.; Watt, Janet T.

    2016-09-12

    IntroductionFrom November 2011 to August 2015, the U.S. Geological Survey (USGS) collected more than 1,000 line-kilometers (length of lines surveyed in kilometers) of marine magnetic data on San Pablo Bay, 98 onshore gravity stations, and over 27 line-kilometers of ground magnetic data in northern California. Combined magnetic and gravity investigations were undertaken to study subsurface geologic structures as an aid in understanding the geologic framework and earthquake hazard potential in the San Francisco Bay Area. Furthermore, marine magnetic data illuminate local subsurface geologic features in the shallow crust beneath San Pablo Bay where geologic exposure is absent.Magnetic and gravity methods, which reflect contrasting physical properties of the subsurface, are ideal for studying San Pablo Bay. Exposed rock units surrounding San Pablo Bay consist mainly of Jurassic Coast Range ophiolite, Great Valley sequence, Franciscan Complex rocks, Miocene sedimentary rocks, and unconsolidated alluvium (Graymer and others, 2006). The contrasting magnetic and density properties of these rocks enable us to map their subsurface extent.

  3. An interactive lake survey program. [airborne multispectral sensor image processing

    NASA Technical Reports Server (NTRS)

    Smith, A. Y.

    1977-01-01

    Consideration is given to the development and operation of the interactive lake survey program developed by the Jet Propulsion Laboratory and the Environmental Protection Agency. The program makes it possible to locate, isolate, and store any number of water bodies on the basis of a given digital image. The stored information may be used to generate statistical analyses of each body of water including the lake surface area and the shoreline perimeter. The hardware includes a 360/65 host computer, a Ramtek G100B display controller, and a trackball cursor. The system is illustrated by the LAKELOC operation as it would be applied to a Landsat scene, noting the FARINA and STATUS programs. The water detection algorithm, which increases the accuracy with which water and land data may be separated, is discussed.

  4. Augmentation the Great Lakes Basin's Geoid by Harmonic Downward Continuing of Newly Acquired Scalar Airborne Gravity Data

    NASA Astrophysics Data System (ADS)

    Roman, Daniel R.; Li, Xiaopeng

    2014-05-01

    Roughly 10% U.S. population and more than 30% of the Canadian population are living around the Great Lakes Basin (Superior, Michigan, Huron, Erie and Ontario as well as the associated watersheds and connecting channels)[1]. The Great Lakes system contains 84% of the North America's surface fresh water and 21% world widely [2,3]. Only the polar ice caps contain more fresh water [1]. Thus, a high resolution accurate geoid will definitely help us to better understand the Great Lakes system and its influences to local and global environmental changes. Over the years, both U.S. and Canada had developed regional geoid models that cover the Great Lakes area. By incorporating the up-to-date satellite information from GRACE and GOCE, the long wavelength component of the geoid is better defined. The newly acquired scalar airborne gravity data in this area is used to augment the middle to short wavelength. A recent study [4] showed that when compared with EGM2008, the airborne data detects the same new features as the satellite model does, but with more detailed information. As a continuation of the previous study, the airborne data will be harmonicly downward continued onto the surface with some predefined bands. Various weighting schemes between surface data and the downward continued airborne data will be carried out to find the most accurate geoid in terms of directly fitting on surface observations from both GPS/Leveling benchmarks and tidal benchmarks on both the U.S. side and the Canadian side. References: 1. "Great Lakes - U.S. EPA". Epa.gov. 2006-06-28. Retrieved 2011-02-19. 2. Waples, James T. (2008). "The Laurentian Great Lakes" (PDF). North American Continental Margins (Great Lakes Environmental Research Laboratory): 73-81. 3 Grady, Wayne (2007). The Great Lakes. Vancouver: Greystone Books and David Suzuki Foundation. pp. 13, 21-26, 42-43. ISBN 978-1-55365-197-0. 4. Daniel R. Roman; Xiaopeng Li; Simon A. Holmes (2013) Regional geoid height models developed using

  5. Airborne Hyperspectral Infrared Imaging Survey of the Southern San Andreas Fault

    NASA Astrophysics Data System (ADS)

    Lynch, D. K.; Tratt, D. M.; Buckland, K. N.; Johnson, P. D.

    2014-12-01

    The San Andreas Fault (SAF) between Desert Hot Springs and Bombay Beach has been surveyed with Mako, an airborne hyperspectral imager operating across the wavelength range 7.6-13.2 μm in the thermal-infrared (TIR) spectral region. The data were acquired with a 4-km swath width centered on the SAF, and many tectonic features are recorded in the imagery. Spectral analysis using diagnostic features of minerals can identify rocks, soils and vegetation. Mako imagery can also locate rupture zones and measure slip distances. Designed and built by The Aerospace Corporation, the innovative and highly capable airborne imaging spectrometer used for this work enables low-noise performance (NEΔT ≲ 0.1 K @ 10 μm) at small pixel IFOV (0.55 mrad) and high frame rates, making possible an area-coverage rate of 20 km2 per minute with 2-m ground resolution from 12,500 ft (3.8 km) above-ground altitude. Since its commissioning in 2010, Mako has been used in numerous studies involving other earthquake fault systems (Hector Mine, S. Bristol Mts.), mapping of surface geology, geothermal sources (fumaroles near the Salton Sea), urban surveys, and the detection, quantification, and tracking of natural and anthropogenic gaseous emission plumes. Mako is available for airborne field studies and new applications are of particular interest. It can be flown at any altitude below 20,000 ft to achieve the desired GSD.

  6. Airborne Surveys of Snow Depth over Arctic Sea Ice

    NASA Technical Reports Server (NTRS)

    Kwok, R.; Panzer, B.; Leuschen, C.; Pang, S.; Markus, T.; Holt, B.; Gogineni, S.

    2011-01-01

    During the spring of 2009, an ultrawideband microwave radar was deployed as part of Operation IceBridge to provide the first cross-basin surveys of snow thickness over Arctic sea ice. In this paper, we analyze data from three approx 2000 km transects to examine detection issues, the limitations of the current instrument, and the regional variability of the retrieved snow depth. Snow depth is the vertical distance between the air \\snow and snow-ice interfaces detected in the radar echograms. Under ideal conditions, the per echogram uncertainty in snow depth retrieval is approx 4 - 5 cm. The finite range resolution of the radar (approx 5 cm) and the relative amplitude of backscatter from the two interfaces limit the direct retrieval of snow depths much below approx 8 cm. Well-defined interfaces are observed over only relatively smooth surfaces within the radar footprint of approx 6.5 m. Sampling is thus restricted to undeformed, level ice. In early April, mean snow depths are 28.5 +/- 16.6 cm and 41.0 +/- 22.2 cm over first-year and multiyear sea ice (MYI), respectively. Regionally, snow thickness is thinner and quite uniform over the large expanse of seasonal ice in the Beaufort Sea, and gets progressively thicker toward the MYI cover north of Ellesmere Island, Greenland, and the Fram Strait. Snow depth over MYI is comparable to that reported in the climatology by Warren et al. Ongoing improvements to the radar system and the utility of these snow depth measurements are discussed.

  7. Detailed Analysis of Marine Gravity Survey Data from Panama Canal Transits: Improving Error Models and Signal Processing for BGM-3 Marine Gravimeter Survey Systems

    NASA Astrophysics Data System (ADS)

    Sailor, R. V.; Medler, C. L.; Kinsey, J. C.; Zettergren, E. W.; Insanic, E.

    2015-12-01

    Our prior work (Sailor et al., 2015) showed that the Panama Canal locking operations impart a peak vertical acceleration of about 60 mGal (6 x 10-4 m/sec2) to ships as the individual lock chambers are filled or emptied. During a period of 8 to 12 minutes the ship's elevation changes by over 8 meters. This motion is very repeatable, since it is driven by gravity-fed hydraulics backed up by a huge mass of water. The novelty of the prior work was to demonstrate that the lock-driven vertical acceleration is significant, of relatively long duration, easily observed by the BGM-3 accelerometer/gravimeter, and is equivalent tothe gravity anomaly caused by a moderately-sized seamount. Thus, the lock-induced vertical acceleration is a known external acceleration input that falls within the amplitude and time duration band of interest for marine gravity as well as airborne gravity survey systems. Here we report an extension to the prior work, using BGM-3 gravimeter data from the RV Marcus G Langseth and the RV Melville, in addition to the previously-used two datasets from the RV Knorr. The new analysis allows us to compare the quality of the gravity data from these three ships in two ways, using: 1) Differences along nearly perfectly coincident gravity anomaly data profiles collected underway, during passage through calm and narrow channels with little or no vertical ship motion; and 2) Observed vertical-motion-induced accelerations, with no horizontal motion, experienced during lock operations. We use the raw 1-Hz output of the BGM-3 gravimeter and compare various filtering methods. Furthermore, good quality vertical channel GPS is used to compare to the output of our solution of a boundary value problem: Given the observed outputs of the gravimeter, solve for h(t), the elevation of the ship vs time and also for two parameters: initial gravity value prior to vertical motion in the lock and apparent vertical gravity gradient.

  8. Airborne radioactivity surveys in the Mojave Desert region, Kern, Riverside, and San Bernardino Counties, California

    USGS Publications Warehouse

    Moxham, Robert M.

    1952-01-01

    Airborne radioactivity surveys in the Mojave Desert region Kern, Riverside, and Bernardino counties were made in five areas recommended as favorable for the occurrence of radioactive raw materials: (1) Rock Corral area, San Bernardino County. (2) Searles Station area, Kern county. (3) Soledad area, Kern County. (4) White Tank area, Riverside and San Bernardino counties. (5) Harvard Hills area, San Bernardino County. Anomalous radiation was detected in all but the Harvard Hills area. The radioactivity anomalies detected in the Rock Corral area are of the greatest amplitude yet recorded by the airborne equipment over natural sources. The activity is apparently attributable to the thorium-beating mineral associated with roof pendants of crystalline metamorphic rocks in a granitic intrusive. In the Searles Station, Soledad, and White Tank area, several radioactivity anomalies of medium amplitude were recorded, suggesting possible local concentrations of radioactive minerals.

  9. Upgrading the GT-2A aerogravimetric complex for airborne gravity measurements in the Arctic

    NASA Astrophysics Data System (ADS)

    Koneshov, V. N.; Klevtsov, V. V.; Solov'ev, V. N.

    2016-05-01

    The methodical solutions for improving the GT-2A aerogravimetric complexes by incorporating the Javad Quattro-G3D GPS receiver connected to four antennas spaced in two orthogonal planes are discussed. The operation features of the advanced aerogravimetric complex are described and the results of its application during the testing flight to 78° N latitude are presented. The anomalous gravity obtained in the testing flight is compared with the EGM2008 and EIGEN-6C models.

  10. Development of a Network RTK Positioning and Gravity-Surveying Application with Gravity Correction Using a Smartphone

    PubMed Central

    Kim, Jinsoo; Lee, Youngcheol; Cha, Sungyeoul; Choi, Chuluong; Lee, Seongkyu

    2013-01-01

    This paper proposes a smartphone-based network real-time kinematic (RTK) positioning and gravity-surveying application (app) that allows semi-real-time measurements using the built-in Bluetooth features of the smartphone and a third-generation or long-term evolution wireless device. The app was implemented on a single smartphone by integrating a global navigation satellite system (GNSS) controller, a laptop, and a field-note writing tool. The observation devices (i.e., a GNSS receiver and relative gravimeter) functioned independently of this system. The app included a gravity module, which converted the measured relative gravity reading into an absolute gravity value according to tides; meter height; instrument drift correction; and network adjustments. The semi-real-time features of this app allowed data to be shared easily with other researchers. Moreover, the proposed smartphone-based gravity-survey app was easily adaptable to various locations and rough terrain due to its compact size. PMID:23857258

  11. Development of a network RTK positioning and gravity-surveying application with gravity correction using a smartphone.

    PubMed

    Kim, Jinsoo; Lee, Youngcheol; Cha, Sungyeoul; Choi, Chuluong; Lee, Seongkyu

    2013-01-01

    This paper proposes a smartphone-based network real-time kinematic (RTK) positioning and gravity-surveying application (app) that allows semi-real-time measurements using the built-in Bluetooth features of the smartphone and a third-generation or long-term evolution wireless device. The app was implemented on a single smartphone by integrating a global navigation satellite system (GNSS) controller, a laptop, and a field-note writing tool. The observation devices (i.e., a GNSS receiver and relative gravimeter) functioned independently of this system. The app included a gravity module, which converted the measured relative gravity reading into an absolute gravity value according to tides; meter height; instrument drift correction; and network adjustments. The semi-real-time features of this app allowed data to be shared easily with other researchers. Moreover, the proposed smartphone-based gravity-survey app was easily adaptable to various locations and rough terrain due to its compact size. PMID:23857258

  12. Airborne and field-temperature surveys compared at Long Valley KGRA, California

    SciTech Connect

    Del Grande, N.K.

    1981-06-01

    An airborne predawn radiometric temperature survey was flown over the Long Valley KGRA. Radiometric temperatures were recorded at 10 to 12 ..mu..m and 4.5 to 5.5 ..mu..m. They were corrected to obtain true land-surface temperatures in agreement with field data. After accounting for thermal effects from surface features, there remained a thermal anomaly. The anomalous zone encompassed 2 km/sup 2/. It was a dry land area with a predawn surface temperature which averaged 1.4 +- 0.3/sup 0/C warmer than ambient. This area coincided with a thermal discharge zone where deep temperature gradients were 5 to 30 times normal. The predawn radiometric survey clarified and supplemented conclusions drawn from 6 to 30m deep field surveys. Heat from hydrothermal discharge was stored in a shallow aquifer and conducted to the surface.

  13. Manganese survey in airborne particulate matter from a mining area at Hidalgo State, Mexico

    NASA Astrophysics Data System (ADS)

    Aldape, F.; Hernández-Méndez, B.; Flores M, J.

    1999-04-01

    A manganese (Mn) survey in airborne particulate matter from a mining area located in Hidalgo State (Mexico) was performed using PIXE. Deposits of Mn ore, first discovered in 1959 and under continuous exploitation since 1962, are nowadays considered as one of the most important of their kind in the American Continent. Afterwards, local inhabitants have been under continuous overexposure to dusts and water highly enriched with Mn. Since no information was available about Mn content in airborne particulate matter in that area, especially in the respirable fraction PM 2.5, airborne particles were collected simultaneously at two sites located on opposite sides of the rim of the mining valley, and along the line of prevailing local winds. The sample collection was performed on eight alternate days, taking two samples per day (day-time and night-time) at each sampling site, using Stacked Filter Units (SFUs) of the Davis design to separate particles into fine (PM 2.5) and coarse (PM 15) sizes. The samples were PIXE analyzed and the results of this study revealed that Mn content, in both fine and coarse fractions, were in excess of the general urban background level of 40 ng/m 3 (US Environmental Protection Agency, 1990) in more than 50% of the samples, which indicate severe environmental deterioration in the place under study.

  14. Airborne-temperature-survey maps of heat-flow anomalies for exploration geology

    NASA Astrophysics Data System (ADS)

    Delgrande, N. K.

    1982-11-01

    Precise airborne temperature surveys depicted small predawn surface temperature differences related to heat flow anomalies at the Long Valley, California, KGRA. Zones with conductive heat flow differences of 45 + or - 16 nu cal/sq cm(s) has predawn surface temperature differences of 1.4 + or - 0.3 C. The warmer zones had hot water circulating in a shallow (less than 60-m-deep) aquifer. Hot wate is a useful geochemical indicator of geothermal and mineral resource potential. The precise airborne temperature survey method recorded redundant infrared scanner signals at two wavelengths (10 to 12 micrometers and 4.5 to 5.5 micrometers) and two elevations (0.3 km and 1.2 km). Ground thermistor probes recorded air and soil temperatures during the survey overflights. Radiometric temperatures were corrected for air path and reflected sky radiation effects. Corrected temperatures were displayed in image form with color coded maps which depicted 0.24 C temperature differences.

  15. Airborne EM survey in volcanoes : Application to a volcanic hazards assessment

    NASA Astrophysics Data System (ADS)

    Mogi, T.

    2010-12-01

    Airborne electromagnetics (AEM) is a useful tool for investigating subsurface structures of volcanoes because it can survey large areas involving inaccessible areas. Disadvantages include lower accuracy and limited depth of investigation. AEM has been widely used in mineral exploration in frontier areas, and have been applying to engineering and environmental fields, particularly in studies involving active volcanoes. AEM systems typically comprise a transmitter and a receiver on an aircraft or in a towed bird, and although effective for surveying large areas, their penetration depth is limited because the distance between the transmitter and receiver is small and higher-frequency signals are used. To explore deeper structures using AEM, a semi-airborne system called GRounded Electrical source Airborne Transient ElectroMagnetics (GREATEM) has been developed. The system uses a grounded-electrical-dipole as the transmitter and generates horizontal electric fields. The GREATEM technology, first proposed by Mogi et al. (1998), has recently been improved and used in practical surveys (Mogi et al., 2009). The GREATEM survey system was developed to increase the depth of investigation possible using AEM. The method was tested in some volcanoes at 2004-2005. Here I will talk about some results of typical AEM surveys and GREATEM surveys in some volcanoes in Japan to mitigate hazards associated with volcano eruption. Geologic hazards caused by volcanic eruptions can be mitigated by a combination of prediction, preparedness and land-use control. Risk management depends on the identification of hazard zones and forecasting of eruptions. Hazard zoning involves the mapping of deposits which have formed during particular phases of volcanic activity and their extrapolation to identify the area which would be likely to suffer a similar hazard at some future time. The mapping is usually performed by surface geological surveys of volcanic deposits. Resistivity mapping by AEM is useful

  16. Initial Field Measurements with the Multisensor Airborne Radiation Survey (MARS) High Purity Germanium (HPGe) Detector Array

    SciTech Connect

    Fast, James E.; Bonebrake, Christopher A.; Dorow, Kevin E.; Glasgow, Brian D.; Jensen, Jeffrey L.; Morris, Scott J.; Orrell, John L.; Pitts, W. Karl; Rohrer, John S.; Todd, Lindsay C.

    2010-06-29

    Abstract: The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.

  17. Airborne gamma-ray spectrometer and magnetometer survey: north/south tieline. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted along the 99/sup 0/ longitude meridian from the Canadian border southward to the Mexican border. A total of 1555 line miles of geophysical data were acquired and, subsequently, compiled. The north-south tieline was flown as part of the National Uranium Resources Evaluation. NURE is a program of the US Department of Energy's Grand Junction, Colorado, office to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  18. Predicting gravity and sediment thickness in Afghanistan

    NASA Astrophysics Data System (ADS)

    Jung, W.; Brozena, J.; Peters, M.

    2013-02-01

    The US Naval Research Laboratory conducted comprehensive high-altitude (7 km above mean sea level) aero-geophysical surveys over Afghanistan in 2006 (Rampant Lion I). The surveys were done in collaboration with the US Geological Survey and upon the request of Islamic Republic of Afghanistan Ministry of Mines. In this study, we show that a best fitting admittance between topography and airborne gravity in western Afghanistan can be used to predict airborne gravity for the no-data area of eastern Afghanistan where the mountains are too high to conduct airborne surveys, due to the threat of ground fire. The differences between the airborne and the predicted gravity along a tie-track through the no-data area were found to be within ±12 mGal range with rms difference 7.3 mGal, while those between the predicted gravity from a simple Airy model (with compensation depth of 32 km and crustal density of 2.67 g cm-3) and the airborne gravity were within ±22 mGal range with rms difference 10.3 mGal. A combined airborne free-air anomaly has been constructed by merging the predicted gravity with the airborne data. We also demonstrate that sediment thickness can be estimated for basin areas where surface topography and airborne free-air anomaly profiles do not show a correlation presumably because of thick sediments. In order to estimate sediment thickness, we first determine a simple linear relationship from a scatter plot of the airborne gravity points and the interpolated Shuttle Radar Topography Mission (SRTM) topography along the Rampant Lion I tracks, and computed corresponding quasi-topography tracks by multiplying the linear relationship with the airborne free-air anomalies. We then take the differences between the SRTM and quasi-topography as a first-order estimate of sediment thickness. A global gravity model (GOCO02S), upward continued to the same altitude (7 km above mean sea level) as the data collection, was compared with the low-pass filtered (with cutoff

  19. Detailed gravity and aeromagnetic surveys in the Black Rock Desert Area, Utah. Topical report

    SciTech Connect

    Serpa, L.F.; Cook, K.L.

    1980-01-01

    Aeromagnetic and gravity surveys were conducted during 1978 in the Black Rock Desert, Utah over an area of about 2400 km/sup 2/ between the north-trending Pavant and Cricket Mountains. The surveys assisted in evaluating the geothermal resources in the Meadow-Hatton Known Geothermal Resource Area (KGRA) and vicinity by delineating geophysical characteristics of the subsurface. The gravity measurements from approximately 700 new stations were reduced to complete Bouguer gravity anomaly values with the aid of a computerized terrain-correction program and contoured at an interval of 1 milligal. The aeromagnetic survey was drape flown at an altitude of 305 m (1000 ft) and a total intensity residual aeromagnetic map with a contour interval of 20 gammas was produced. Two gravity and aeromagnetic east-west profiles and one north-south profile were modeled using a simultaneous 2 1/2-dimensional modeling technique to provide a single model satisfying both types of geophysical data.

  20. Geophex Airborne Unmanned Survey System (GAUSS). Topical report, October 1993--September 1996

    SciTech Connect

    1998-12-31

    This document is a Final Technical Report that describes the results of the Geophex Airborne Unmanned Survey System (GAUSS) research project. The objectives were to construct a geophysical data acquisition system that uses a remotely operated unmanned aerial vehicle (UAV) and to evaluate its effectiveness for characterization of hazardous environmental sites. The GAUSS is a data acquisition system that mitigates the potential risk to personnel during geophysical characterization of hazardous or radioactive sites. The fundamental basis of the GAUSS is as follows: (1) an unmanned survey vehicle carries geophysical sensors into a hazardous location, (2) the pilot remains outside the hazardous site and operates the vehicle using radio control, (3) geophysical measurements and their spatial locations are processed by an automated data-acquisition system which displays data on an off-site monitor in real-time, and (4) the pilot uses the display to direct the survey vehicle for complete site coverage. The objective of our Phase I research was to develop a data acquisition and processing (DAP) subsystem and geophysical sensors suitable for UAV deployment. We integrated these two subsystems to produce an automated, hand-held geophysical surveying system. The objective of the Phase II effort was to modify the subsystems and integrate them into an airborne prototype. The completed GAUSS DAP system consists of a UAV platform, a laser tracking and ranging subsystem, a telemetry subsystem, light-weight geophysical sensors, a base-station computer (BC), and custom-written survey control software (SCS). We have utilized off-the-shelf commercial products, where possible, to reduce cost and design time.

  1. Airborne full tensor magnetic gradiometry surveys in the Thuringian basin, Germany

    NASA Astrophysics Data System (ADS)

    Queitsch, M.; Schiffler, M.; Goepel, A.; Stolz, R.; Meyer, M.; Meyer, H.; Kukowski, N.

    2013-12-01

    In this contribution we introduce a newly developed fully operational full tensor magnetic gradiometer (FTMG) instrument based on Superconducting Quantum Interference Devices (SQUIDs) and show example data acquired in 2012 within the framework of the INFLUINS (Integrated Fluid Dynamics in Sedimentary basins) project. This multidisciplinary project aims for a better understanding of movements and interaction between shallow and deep fluids in the Thuringian Basin in the center of Germany. In contrast to mapping total magnetic field intensity (TMI) in conventional airborne magnetic surveys for industrial exploration of mineral deposits and sedimentary basins, our instrument measures all components of the magnetic field gradient tensor using highly sensitive SQUID gradiometers. This significantly constrains the solutions of the inverse problem. Furthermore, information on the ratio between induced and remanent magnetization is obtained. Special care has been taken to reduce motion noise while acquiring data in airborne operation. Therefore, the sensors are mounted in a nonmagnetic and aerodynamically shaped bird made of fiberglas with a high drag tail which stabilizes the bird even at low velocities. The system is towed by a helicopter and kept at 30m above ground during data acquisition. Additionally, the system in the bird incorporates an inertial unit for geo-referencing and enhanced motion noise compensation, a radar altimeter for topographic correction and a GPS system for high precision positioning. Advanced data processing techniques using reference magnetometer and inertial unit data result in a very low system noise of less than 60 pT/m peak to peak in airborne operation. To show the performance of the system we present example results from survey areas within the Thuringian basin and along its bordering highlands. The mapped gradient tensor components show a high correlation to existing geologic maps. Furthermore, the measured gradient components indicate

  2. NASA IceBridge: Scientific Insights from Airborne Surveys of the Polar Sea Ice Covers

    NASA Astrophysics Data System (ADS)

    Richter-Menge, J.; Farrell, S. L.

    2015-12-01

    The NASA Operation IceBridge (OIB) airborne sea ice surveys are designed to continue a valuable series of sea ice thickness measurements by bridging the gap between NASA's Ice, Cloud and Land Elevation Satellite (ICESat), which operated from 2003 to 2009, and ICESat-2, which is scheduled for launch in 2017. Initiated in 2009, OIB has conducted campaigns over the western Arctic Ocean (March/April) and Southern Oceans (October/November) on an annual basis when the thickness of sea ice cover is nearing its maximum. More recently, a series of Arctic surveys have also collected observations in the late summer, at the end of the melt season. The Airborne Topographic Mapper (ATM) laser altimeter is one of OIB's primary sensors, in combination with the Digital Mapping System digital camera, a Ku-band radar altimeter, a frequency-modulated continuous-wave (FMCW) snow radar, and a KT-19 infrared radiation pyrometer. Data from the campaigns are available to the research community at: http://nsidc.org/data/icebridge/. This presentation will summarize the spatial and temporal extent of the OIB campaigns and their complementary role in linking in situ and satellite measurements, advancing observations of sea ice processes across all length scales. Key scientific insights gained on the state of the sea ice cover will be highlighted, including snow depth, ice thickness, surface roughness and morphology, and melt pond evolution.

  3. Gravity survey of marine field: Case study for Silurian reef exploration

    SciTech Connect

    Heigold, P.C.; Whitaker, S.T. )

    1989-08-01

    A gravity survey conducted over and around Marine field in southwestern Illinois has been used as an example to show how measurement of the local gravity field can aid in the search for Silurian reefs in the Illinois basin. Acquisition parameters for gravity surveys over Silurian reefs should be calculated beforehand from simple models of the reef based on estimates of density contrasts, depths, and size. Residual and derivative mapping techniques generally enhance gravity anomalies and enable more accurate portrayals of the structural relief on buried reefs. The second vertical derivative map of the residual Bouguer gravity anomaly surface at Marine field compares very well with the structure of the reef as mapped from subsurface data. This study indicates that similar mapping techniques could be effective on other reefs throughout the Illinois basin. Although gravity mapping methods are potentially powerful exploration tools in themselves, the writers believe that their proper role is as a part of a more comprehensive exploration approach. Gravity surveys can be used effectively as an initial exploration method in reef-prone areas to define smaller, prospect-size areas in which more intensive exploration techniques can subsequently be focused.

  4. Airborne Hyperspectral Survey of Afghanistan 2007: Flight Line Planning and HyMap Data Collection

    USGS Publications Warehouse

    Kokaly, Raymond F.; King, Trude V.V.; Livo, K. Eric

    2008-01-01

    Hyperspectral remote sensing data were acquired over Afghanistan with the HyMap imaging spectrometer (Cocks and others, 1998) operating on the WB-57 high altitude NASA research aircraft (http://jsc-aircraft-ops.jsc.nasa.gov/wb57/index.html). These data were acquired during the interval of August 22, 2007 to October 2, 2007, as part of the United States Geological Survey (USGS) project 'Oil and Gas Resources Assessment of the Katawaz and Helmand Basins'. A total of 218 flight lines of hyperspectral remote sensing data were collected over the country. This report describes the planning of the airborne survey and the flight lines that were flown. Included with this report are digital files of the nadir tracks of the flight lines, including a map of the labeled flight lines and corresponding vector shape files for geographic information systems (GIS).

  5. A 0.4 to 10 GHz airborne electromagnetic environment survey of USA urban areas

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Hill, J. S.

    1976-01-01

    An airborne electromagnetic-environment survey of some U.S. metropolitan areas measured terrestrial emissions within the broad frequency spectrum from 0.4 to 10 GHz. A Cessna 402 commercial aircraft was fitted with both nadir-viewing and horizon-viewing antennas and instrumentation, including a spectrum analyzer, a 35 mm continuous film camera, and a magnetic tape recorder. Most of the flights were made at a nominal altitude of 10,000 feet, and Washington, D. C., Baltimore, Philadelphia, New York, and Chicago were surveyed. The 450 to 470 MHz land-mobile UHF band is especially crowded, and the 400 to 406 MHz space bands are less active. This paper discusses test measurements obtained up to 10 GHz. Sample spectrum analyzer photograhs were selected from a total of 5,750 frames representing 38 hours of data.

  6. 0.4- to 10-GHz airborne electromagnetic-environment survey of United States urban areas

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Hill, J. S.

    1976-01-01

    An airborne electromagnetic-environment survey of some U.S. metropolitan areas measured terrestrial emissions within the broad-frequency spectrum from 0.4 to 10 GHz. A Cessna 402 commercial aircraft was fitted with both nadir-viewing and horizon-viewing antennas and instrumentation, including a spectrum analyzer, a 35-mm continuous-film camera, and a magnetic-tape recorder. Most of the flights were made at a nominal altitude of 10,000 ft, and Washington, Baltimore, Philadelphia, New York, and Chicago were surveyed. The 450- to 470-MHz land-mobile UHF band is especially crowded, and the 400- to 406-MHz space bands are less active. Test measurements obtained up to 10 GHz are discussed. Sample spectrum-analyzer photographs were selected from a total of 5750 frames representing 38 hours of data.

  7. Gravity Survey on the Glass Buttes Geothermal Exploration Project Lake County, Oregon

    DOE Data Explorer

    John Akerley

    2011-10-12

    This report covers data acquisition, instrumentation and processing of a gravity survey performed on the Glass Buttes Geothermal Exploration Project, located in Lake County, Oregon for ORMAT Technologies Inc. The survey was conducted during 21 June 2010 to 26 June 2010. The survey area is located in T23S, R21-23E and lies within the Glass Buttes, Hat Butte, and Potato Lake, Oregon 1:24,000 topographic sheets. A total of 180 gravity stations were acquired along five profile lines.

  8. Bathymetry of Patagonia glacier fjords and glacier ice thickness from high-resolution airborne gravity combined with other data

    NASA Astrophysics Data System (ADS)

    An, L.; Rignot, E.; Rivera, A.; Bunetta, M.

    2012-12-01

    The North and South Patagonia Ice fields are the largest ice masses outside Antarctica in the Southern Hemisphere. During the period 1995-2000, these glaciers lost ice at a rate equivalent to a sea level rise of 0.105 ± 0.001 mm/yr. In more recent years, the glaciers have been thinning more quickly than can be explained by warmer air temperatures and decreased precipitation. A possible cause is an increase in flow speed due to enhanced ablation of the submerged glacier fronts. To understand the dynamics of these glaciers and how they change with time, it is critical to have a detailed view of their ice thickness, the depth of the glacier bed below sea or lake level, how far inland these glaciers remain below sea or lake level, and whether bumps or hollows in the bed may slow down or accelerate their retreat. A grid of free-air gravity data over the Patagonia Glaciers was collected in May 2012 and October 2012, funded by the Gordon and Betty Moore Foundation (GBMF) to measure ice thickness and sea floor bathymetry. This survey combines the Sander Geophysics Limited (SGL) AIRGrav system, SGL laser altimetry and Chilean CECS/UCI ANDREA-2 radar. To obtain high-resolution and high-precision gravity data, the helicopter operates at 50 knots (25.7 m/s) with a grid spacing of 400m and collects gravity data at sub mGal level (1 Gal =1 Galileo = 1 cm/s2) near glacier fronts. We use data from the May 2012 survey to derive preliminarily high-resolution, high-precision thickness estimates and bathymetry maps of Jorge Montt Glacier and San Rafael Glacier. Boat bathymetry data is used to optimize the inversion of gravity over water and radar-derived thickness over glacier ice. The bathymetry maps will provide a breakthrough in our knowledge of the ice fields and enable a new era of glacier modeling and understanding that is not possible at present because ice thickness is not known.

  9. Airborne radioactivity survey of parts of the Atlantic Ocean beach, North and South Carolina

    USGS Publications Warehouse

    Meuschke, J.L.; Moxham, R.M.; Bortner, T.E.

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey along the Atlantic Ocean beach between Edisto Island, South Carolina and Cape Fear, North Carolina. The survey was made May 20, 1953, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a Douglas DC-3 aircraft and consisted of one flight line, at a 500-foot altitude, parallel to the beach. The vertical projection of the flight line coincided approximately with the landward limit of the modern beach. The width of the zone on the ground from which anomalous radiation is measured at the nominal 500 foot flight altitude varies with areal extent and intensity of radioactivity of the source. For strong sources of radioactivity the width of the zone may be as much as 1400 feet. The accompanying maps show the approximate locations of the areas of greater-than-average radioactivity (at left) and the location of the traverse flown (at right). The abnormal radioactivity is apparently caused by radioactive minerals associated with "black sand" deposits which occur locally along the beach in this region. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or a combination of these elements. It is not possible to determine the extent or radioactive content of the materials responsible for the abnormal radioactivity. The information given in the accompanying map showing the localities of greater-than-average radioactivity therefore, suggests areas in which uranium and thorium deposits are more likely to occur.

  10. Airborne radioactivity survey of the Gulf of Mexico beach between Sanibel Island and Caladesi Island, Florida

    USGS Publications Warehouse

    Meuschke, J.L.; Moxham, R.M.; Bortner, T.E.

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey along the Gulf of Mexico beach between Sanibel Island and Caladesi Island in Florida. This survey was made May 4, 1953, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a Douglas DC-3 aircraft and consisted of one flight line, at a 500-foot altitude , parallel to the beach. The vertical projection of the flight line coincided approximately with the landward limit of the modern beach. The width of the zone on the ground from which anomalous radiation is measured at the nominal 500 foot flight altitude varies with the areal extent and intensity of the radioactivity the width of the zone may be as much as 1400 feet. The accompanying map and index map show the approximate locations of the areas of greater-than-average radioactivity and the location of the traverse flown. The abnormal radioactivity is apparently caused by radioactive minerals associated with "black sand" deposits which occur locally along the beach in the region. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or to a combination of these elements. It is not possible to determine the extent or radioactive content of the materials responsible for the abnormal radioactivity. The information given in the accompanying map showing the localities of greater-than-average radioactivity therefore, suggests area in which uranium or thorium deposits are more likely to occur.

  11. Airborne radioactivity survey of parts of Atlantic Ocean beach, Virginia to Florida

    USGS Publications Warehouse

    Moxham, R.M.; Johnson, R.W.

    1953-01-01

    The accompanying maps show the results of an airborne radioactivity survey along the Atlantic Ocean beach from Cape Henry, Virginia to Cape Fear, North Carolina and from Savannah Bach Georgia to Miami Beach, Florida. The survey was made March 23-24, 1953, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a Douglas DC-3 aircraft and consisted of one flight line, at a 500-foot altitude, parallel to the beach. The vertical projection of the flight line coincided approximately with the landward limit of the modern beach. The width of the zone on the ground from which anomalous radiation is measured at the normal 500 foot flight altitude varies with the areal extent radioactivity of the source. For strong sources of radioactivity the width of the zone would be as much as 1,400 feet. The location of the flight lines is shown on the index map below. No abnormal radioactivity was detected along the northern flight line between Cape Henry, Virginia and Cape Fear, North Carolina. Along the southern flight line fourteen areas of abnormal radioactivity were detected between Savannah Beach, Georgia and Anastasia Island, Florida as shown on the map on the left. The abnormal radioactivity is apparently due to radioactive minerals associated with "black sand" deposits with occur locally along the beach in this region. The present technique of airborne radioactivity measurement does not permit distinguishing between activity sue to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or to a combination of these elements. It is not possible to determine the extent or radioactive content of the materials responsible for the abnormal radioactivity. The information given on the accompanying map indicates only those localities of greater-than-average radioactivity and, therefore suggest areas in which uranium and thorium deposits are more

  12. Borehole Gravity Meter Surveys at the Waste Treatment Plant, Hanford, Washington.

    SciTech Connect

    MacQueen, Jeffrey D.; Mann, Ethan

    2007-04-06

    Microg-LaCoste (MGL) was contracted by Pacfic Northwest National Laboratories (PNNL) to record borehole gravity density data in 3 wells at the HanfordWaste Treatment Plant (WTP) site. The survey was designed to provide highly accurate density information for use in seismic modeling. The borehole gravity meter (BHGM) tool has a very large depth of investigation (hundreds of feet) compared to other density tools so it is not influenced by casing or near welbore effects, such as washouts.

  13. Airborne radioactivity survey of the Miller Hill area, Carbon county, Wyoming

    USGS Publications Warehouse

    Meuschke, J.L.; Moxham, R.M.

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey covering 65 square miles northwest of Miller Hill, Carbon county, Wyoming. The survey was made by the U.S. Geological Survey as part of a cooperative program with the U.S. Atomic Energy Commission. At 500 feet above the ground, the width of the zone from which anomalous radioactivity is measured varies with the intensity of radiation of the source and, for strong sources, the width would be as much as 1,400 feet. Quarter-mile spacing of the flight paths of the aircraft should be adequate to detect anomalies from strong sources of radioactivity. However, small areas of considerable radioactivity midway between flight paths may not be noted. The approximate location of each radioactivity anomaly is shown on the accompanying map. The plotted position of an anomaly may be in error by as much as a quarter of a mile owing to errors in the available base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The radioactivity anomalies shown on the accompanying map cannot be interpreted in terms of either the radioactive content or the extent of the source materials. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to uranium, or to thorium, or to a combination of uranium and thorium. The radioactivity that is recorded by airborne measurements at 500 feet above the ground can be caused by: 1. A moderately large area in which the rocks and soils are slightly more radioactive than the rocks and soils of the surrounding area. 2. A smaller area in which the rocks and soils are considerably more radioactive than rocks and soils in the surrounding area. 3. A very small area in which to rocks and soils are much more radioactive than the rocks and soils of the surrounding area. Any particular anomaly

  14. Airborne gamma-ray spectrometer survey data application in spatial methods

    SciTech Connect

    Bresnahan, P.J.

    1996-12-31

    The purpose of this research was to develop a methodology that used geographic information system (GIS) tools to convert airborne gamma-ray spectrometer (AGRS) survey data to various spatial data formats for use in radiological hazard mapping and risk assessments. The importance of this conversion methodology results from the versatility and consistency of spatial interpolations using commercially supported software as opposed to previous methods. Maps of interpolated AGRS data provide potential radiological hazard boundaries, delineated by user-defined limits, to guide intense field surveys. Resulting GIS products may be combined with other risk assessment inputs to model and monitor hazardous environments. The AGRS data used in this research was collected during the 1991 sitewide survey at Savannah River site (SRS) as part of the comprehensive integrated remote sensing (CIRS) program conducted by EG&G for the SRS. The AGRS survey component of the program is designed to provide a database for studying the transport of manufactured radionuclides through the environment at the SRS and surrounding areas. The AGRS data have historically been presented only in hardcopy format as acetate overlays on aerial photography. Recently, digital files representing contoured isotopic response have been delivered to the SRS as GIS themes. Since AGRS data are often a collection of dense sample points, interpolation of the data has previously been conducted by connecting points in series along flight paths. To improve on the original algorithm used to contour AGRS data, a triangulated irregular network (TIN) was used as the data model for contour and raster generation.

  15. NASA IceBridge: Airborne surveys of the polar sea ice covers

    NASA Astrophysics Data System (ADS)

    Richter-Menge, J.; Farrell, S. L.

    2014-12-01

    The NASA Operation IceBridge (OIB) airborne sea ice surveys are designed to continue a valuable series of sea ice thickness measurements by bridging the gap between NASA's Ice, Cloud and Land Elevation Satellite (ICESat), which operated from 2003 to 2009, and ICESat-2, which is scheduled for launch in 2017. Initiated in 2009, OIB has conducted campaigns over the western Arctic Ocean (March/April) and Southern Oceans (October/November) on an annual basis. Primary OIB sensors being used for sea ice observations include the Airborne Topographic Mapper laser altimeter, the Digital Mapping System digital camera, a Ku-band radar altimeter, a frequency-modulated continuous-wave (FMCW) snow radar, and a KT-19 infrared radiation pyrometer. Data from the campaigns are available to the research community at: http://nsidc.org/data/icebridge/. This presentation will summarize the spatial and temporal extent of the campaigns and highlight key scientific accomplishments, which include: • Documented changes in the Arctic marine cryosphere since the dramatic sea ice loss of 2007 • Novel snow depth measurements over sea ice in the Arctic • Improved skill of April-to-September sea ice predictions via numerical ice/ocean models • Validation of satellite altimetry measurements (ICESat, CryoSat-2, and IceSat-2/MABEL)

  16. Geoid determination by airborne gravimetry - principles and applications

    NASA Astrophysics Data System (ADS)

    Forsberg, R.; Olesen, A. V.

    2009-12-01

    The operational development of long-range airborne gravimetry has meant that large areas can be covered in a short time frame with high-quality medium-wavelength gravity field data, perfectly matching the needs of geoid determination. Geoid from a combination of surface, airborne and satellite data not only is able to cover the remaining large data voids on the earth, notably Antarctica and tropical jungle regions, but also provide seamless coverage across the coastal zone, and tie in older marine and land gravity data. Airborne gravity can therefore provide essential data for GPS applications both on land and at sea, e.g. for marine construction projects such as bridges, wind mill farms etc. Current operational accuracies with the DTU-Space/UiB airborne system are in the 1-2 mGal range, which translates into geoid accuracies of 5-10 cm, dependent on track spacing. In the paper we will outline the current accuracy of airborne gravity and geoid determination, and show examples from recent international airborne gravity campaigns, aimed at either providing national survey infrastructure, or scientific applications for e.g. oceanography or sea-ice thickness determination.

  17. A Sea Floor Gravity Survey of the Sleipner Field to Monitor CO2 Migration

    SciTech Connect

    Mark Zumberge

    2011-09-30

    Carbon dioxide gas (CO{sub 2}) is a byproduct of many wells that produce natural gas. Frequently the CO{sub 2} separated from the valuable fossil fuel gas is released into the atmosphere. This adds to the growing problem of the climatic consequences of greenhouse gas contamination. In the Sleipner North Sea natural gas production facility, the separated CO{sub 2} is injected into an underground saline aquifer to be forever sequestered. Monitoring the fate of such sequestered material is important - and difficult. Local change in Earth's gravity field over the injected gas is one way to detect the CO{sub 2} and track its migration within the reservoir over time. The density of the injected gas is less than that of the brine that becomes displaced from the pore space of the formation, leading to slight but detectable decrease in gravity observed on the seafloor above the reservoir. Using equipment developed at Scripps Institution of Oceanography, we have been monitoring gravity over the Sleipner CO{sub 2} sequestration reservoir since 2002. We surveyed the field in 2009 in a project jointly funded by a consortium of European oil and gas companies and the US Department of Energy. The value of gravity at some 30 benchmarks on the seafloor, emplaced at the beginning of the monitoring project, was observed in a week-long survey with a remotely operated vehicle. Three gravity meters were deployed on the benchmarks multiple times in a campaign-style survey, and the measured gravity values compared to those collected in earlier surveys. A clear signature in the map of gravity differences is well correlated with repeated seismic surveys.

  18. A Sea Floor Gravity Survey of the Sleipner Field to Monitor CO2 Migration

    SciTech Connect

    Mark Zumberge; Scott Nooner

    2005-12-13

    Since 1996, excess CO{sub 2} from the Sleipner natural gas field has been sequestered and injected underground into a porous saline aquifer 1000 m below the seafloor. In 2002, we carried out a high precision micro-gravity survey on the seafloor in order to monitor the injected CO{sub 2}. A repeatability of 4.3 {micro}Gal in the station averages was observed. This is considerably better than pre-survey expectations. These data will serve as the baseline for time-lapse gravity monitoring of the Sleipner CO{sub 2} injection site. This report covers 3/19/05 to 9/18/05. During this time, gravity and pressure modeling were completed and graduate student Scott Nooner finished his Ph.D. dissertation, of which this work is a major part. Three new ROVDOG (Remotely Operated Vehicle deployable Deep Ocean Gravimeter) instruments were also completed with funding from Statoil. The primary changes are increased instrument precision and increased data sampling rate. A second gravity survey was carried out from August to September of 2005, allowing us to begin examining the time-lapse gravity changes caused by the injection of CO{sub 2} into the underground aquifer, known as the Utsira formation. Preliminary processing indicates a repeatability of 3.6 {micro}Gal, comparable to the baseline survey.

  19. Airborne gamma ray surveying in radon hazard evaluation: a case study from Norway

    NASA Astrophysics Data System (ADS)

    Smethurst, Mark A.; Liv Rudjord, Anne; Finne, Ingvild

    2010-05-01

    The Geological Survey of Norway and Norwegian Radiation Protection Authority have established an approach to mapping radon hazards in Norway based on direct measurements of radon in indoor air, bedrock and drift geology mapping, and the mapping of radium in the ground using helicopter- and aeroplane-borne gamma-ray surveys. Existing indoor radon measurements are used to establish hazard profiles for the other three data sets. The multiple indications of hazard, from all four data sets, are then combined into a single hazard prognosis map. We have looked closely at the efficiency of the mapping method in the municipality of Gran (north of Oslo). The uranium rich alum shale and superficial deposits associated with it are the principal sources of indoor radon in the area. Small isolated granite bodies and local high permeability glacio-fluvial deposits contribute to the hazard picture. The method produces a liberal hazard map that encloses most of the known areas of severe radon contamination in dwellings and identifies additional uninhabited areas where similar levels of contamination can be expected (without mitigating action). The hazard evaluation in the Gran area is 81% efficient at enclosing high indoor radon measurements in the high hazard zone when this zone occupies 50% of the total geographic area. The probability of this distribution happening by chance is 0.054%. Of course, indoor radon measurements are the most valuable data set for establishing radon hazard levels accurately, but only where these measurements are abundant. In Norway such areas are very limited in spatial extent. We find airborne measurements to be the most effective supplementary data, followed in usefulness by knowledge of the bedrock geology and drift geology (at the 1:50,000 mapping scale). A further opportunity to test and refine our approach to radon hazard evaluation presents itself now with a new airborne gamma-ray survey over the Kongsberg region southwest of Oslo. The survey is

  20. A SEA FLOOR GRAVITY SURVEY OF THE SLEIPNER FIELD TO MONITOR CO2 MIGATION

    SciTech Connect

    Mark Zumberge

    2003-06-13

    At the Sleipner gas field, excess CO{sub 2} is sequestered and injected underground into a porous saline aquifer 1000 m below the seafloor. A high precision micro-gravity survey was carried out on the seafloor to monitor the injected CO{sub 2}. A repeatability of 5 {micro}Gal in the station averages was observed. This is considerably better than pre-survey expectations. These data will serve as the baseline for time-lapse gravity monitoring of the Sleipner CO{sub 2} injection site. Simple modeling of the first year data give inconclusive results, thus a more detailed approach is needed. Work towards this is underway.

  1. Airborne gamma-ray spectrometer and magnetometer survey, New Rockford Quadrangle, North Dakota. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over eleven (11) 2/sup 0/ x 1/sup 0/ NTMS quadrangles located in the states of Minnesota and Wisconsin and seven (7) 2/sup 0/ x 1/sup 0/ NTMS quadrangles in North and South Dakota. The quadrangles located within the North and South Dakota survey area include Devil's Lake, New Rockford, Jamestown, Aberdeen, Huron, Mitchell, and Sioux Falls. This report discusses the results obtained over the New Rockford map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately twenty-four (24) miles apart. A total of 21,481 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1397 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  2. Airborne gamma-ray spectrometer and magnetometer survey, Mitchell Quadrangle, South Dakota. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over eleven (11) 2/sup 0/ x 1/sup 0/ NTMS quadrangles located in the states of Minnesota and Wisconsin and seven (7) 2/sup 0/ x 1/sup 0/ NTMS quadrangles in North and South Dakota. The quadrangles located within the North and South Dakota survey area include Devil's Lake, New Rockford, Jamestown, Aberdeen, Huron, Mitchell, and Sioux Falls. This report discusses the results obtained over the Mitchell map area. The purpose of this program is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately twenty-four (24) miles apart. A total of 21,481 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1479 line miles are in this quadrangle.

  3. Airborne gamma-ray spectrometer and magnetometer survey: Huron quadrangle, South Dakota. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over eleven (11) 2/sup 0/ x 1/sup 0/ NTMS quadrangles located in the states of Minnesota and Wisconsin and seven (7) 2/sup 0/ x 1/sup 0/ NTMS quadrangles in North and South Dakota. The quadrangles located within the North and South Dakota survey area include Devil's Lake, New Rockford, Jamestown, Aberdeen, Huron, Mitchell, and Sioux Falls. This report discusses the results obtained over the Huron map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately twenty-four (24) miles apart. A total of 21,481 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1459 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  4. Gravity survey of the Escalante Desert and vicinity, in Iron and Washington Counties, Utah

    SciTech Connect

    Pe, W.; Cook, K.L.

    1980-08-01

    During the summers of 1978 and 1979, a total of 436 new gravity stations were taken in the southern part of the Escalante Desert and vicinity in Iron and Washington counties, Utah. The new stations were combined with 917 other stations taken in previous surveys, and a total of 1353 stations were used in this study, covering an area of about 2700 mi/sup 2/ (7000 km/sup 2/). The purpose of the study was to help evaluate the potential of geothermal resources within the survey area, which includes the Newcastle and Lund KGRA's. All the gravity data were terrain corrected out to a radial distance of 166.7 km from each station, using a computer terrain-correction program. The data were compiled and presented as a complete Bouguer gravity anomaly map with a 2-mgal contour interval. A geologic interpretation of the gravity data was made qualitatively from the gravity map and also quantitatively from four easterly trending gravity profiles taken across the area.

  5. A Survey and Recent Development of Lunar Gravity Assist

    NASA Technical Reports Server (NTRS)

    Penzo, Paul A.

    2000-01-01

    Earth's moon is the largest in the solar system relative to its parent body, the Earth, and can have significant effect on the path of a spacecraft flying close by. This effect, when planned to benefit a specific mission, is called lunar gravity assist (LGA) , and assumes that one aims the spacecraft towards the Moon in such a way that the Moon's gravitational pull will alter the spacecraft's course in a favorable manner. The first application of LGA was in the Apollo program, where the command and lunar modules (and astronauts) were propelled to the Moon such that, if no additional course changes were made, they would swing around the backside of the Moon at a certain altitude and be flung back to Earth to enter the atmosphere at a specified location in the Pacific ocean. This LGA was an essential element saving the lives of the astronauts on Apollo 13. This paper will illustrate the basic mechanics of gravity assist, and list the many applications where it has been used effectively over the past 30 some years. These include missions to the sun and Earth libration points, redirecting a spacecraft from one of these point to a comet encounter, and enhancing payloads by providing an energy boost by the Moon. More recently, studies and actual missions have shown the benefits of LGA in: (1) assisting lunar capture, (2) repositioning geosynchronous communications satellites, (3) boosting spacecraft to Earth escape and departure to planets and other solar system bodies, and (4) allowing small spacecraft to be launched as secondary payloads and released into almost a random orbit from which each may depart and maneuver in space with gravity assists from the Earth and Moon to perform a specific planetary or other mission. This latter application is a recent development by the author and is being applied in 2002 and later years, with piggyback flights on the Ariane 5 which launches comsats to GEO.

  6. Airborne electromagnetic and magnetic geophysical survey data of the Yukon Flats and Fort Wainwright areas, central Alaska, June 2010

    USGS Publications Warehouse

    Ball, Lyndsay B.; Smith, Bruce D.; Minsley, Burke J.; Abraham, Jared D.; Voss, Clifford I.; Astley, Beth N.; Deszcz-Pan, Maria; Cannia, James C.

    2011-01-01

    In June 2010, the U.S. Geological Survey conducted airborne electromagnetic and magnetic surveys of the Yukon Flats and Fort Wainwright study areas in central Alaska. These data were collected to estimate the three-dimensional distribution of permafrost at the time of the survey. These data were also collected to evaluate the effectiveness of these geophysical methods at mapping permafrost geometry and to better define the physical properties of the subsurface in discontinuous permafrost areas. This report releases digital data associated with these surveys. Inverted resistivity depth sections are also provided in this data release, and data processing and inversion methods are discussed.

  7. Airborne radioactivity survey of the Tabernacle Buttes area, Sublette and Fremont counties, Wyoming

    USGS Publications Warehouse

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey in an area of 670 square miles in Sublette and Fremont counties, Wyoming. The survey was made by the U.S. Geological Survey, October 20, 1952, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation-detection equipment mounted in a Douglas DC-3 aircraft. Parallel traverse lines, spaced at quarter-mile intervals, were flown approximately 500 feet above the ground. Aerial photographs were used for pilot guidance, and the flight path of the aircraft was recorded by a gyro-stabilized, continuous-strip-film camera. The distance of the aircraft from the ground was measured with a continuously recording radio altimeter. At 500 feet above the ground, the width of the zone from which anomalous radioactivity is measured varies with the intensity of radiation of the source and, for strong sources, the width would be as much as 1,400 feet. Quarter-mile spacing of the flight paths of the aircraft should be adequate to detect anomalies from strong sources of radioactivity. However, small areas of considerable radioactivity midway between flight paths may not be noted. The approximate location of each radioactivity anomaly is shown on the accompanying map. The plotted position of an anomaly may be in error by as much as a quarter of a mile owing to errors in the available base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The radioactivity anomaly that is recorded by airborne measurements at 500 feet above the ground can be caused by: 1. A moderately large area in which the rocks and soils are slightly more radioactive than the rocks and soils of the surrounding area. 2. A smaller area in which the rocks and soils are considerably more radioactive than rocks and soils in the surrounding area. 3. A very small area in which to rocks and soils are much more radioactive than the rocks and soils of the

  8. Airborne radioactivity survey of the Devils Tower area, Crook county, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.; Moxham, R.M.

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey covering 45 square miles northwest of Devils Tower, Crook County, Wyoming. The survey was made by the U.S. Geological Survey on September 4, 1952, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation-detection equipment mounted in a Douglas DC-3 aircraft. Parallel traverse lines, spaced at quarter-mile intervals, were flown approximately 500 feet above the ground. Aerial photographs were used for pilot guidance, and the flight path of the aircraft was recorded by a gyro-stabilized, continuous-strip-film camera. The distance of the aircraft from the ground was measured with a continuously recording radio altimeter. At 500 feet above the ground, the width of the zone from which anomalous radioactivity is measured varies with the intensity of radiation of the source and, for strong sources, the width would be as much as 1,400 feet. Quarter-mile spacing of the flight paths of the aircraft should be adequate to detect anomalies from strong sources of radioactivity. However, small areas of considerable radioactivity midway between flight paths may not be noted. The approximate location of each radioactivity anomaly is shown on the accompanying map. The plotted position of an anomaly may be in error by as much as a quarter of a mile owing to errors in the available base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The radioactivity that is recorded by airborne measurements at 500 feet above the ground can be caused by: 1. A moderately large area in which the rocks and soils are slightly more radioactive than the rocks and soils of the surrounding area. 2. A smaller area in which the rocks and soils are considerably more radioactive than rocks and soils in the surrounding area. 3. A very small area in which to rocks and soils are much more radioactive than the rocks and soils of the

  9. Airborne radioactivity survey of the Aspen Mountain area, Sweetwater county, Wyoming

    USGS Publications Warehouse

    Meuschke, J.L.; Moxham, R.M.

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey covering 700 square miles in the Aspen Mountain area, Sweetwater county, Wyoming. The survey was made by the U.S. Geological Survey, October 22, 1952, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation-detection equipment mounted in a Douglas DC-3 aircraft. Parallel traverse lines, spaced at quarter-mile intervals, were flown approximately 500 feet above the ground. Aerial photographs were used for pilot guidance, and the flight path of the aircraft was recorded by a gyro-stabilized, continuous-strip-film camera. The distance of the aircraft from the ground was measured with a continuously recording radio altimeter. At 500 feet above the ground, the width of the zone from which anomalous radioactivity is measured varies with the intensity of radiation of the source and, for strong sources, the width would be as much as 1,400 feet. Quarter-mile spacing of the flight paths of the aircraft should be adequate to detect anomalies from strong sources of radioactivity. However, small areas of considerable radioactivity midway between flight paths may not be noted. The approximate location of each radioactivity anomaly is shown on the accompanying map. The plotted position of an anomaly may be in error by as much as a quarter of a mile owing to errors in the available base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The radioactivity anomaly that is recorded by airborne measurements at 500 feet above the ground can be caused by: 1. A moderately large area in which the rocks and soils are slightly more radioactive than the rocks and soils of the surrounding area. 2. A smaller area in which the rocks and soils are considerably more radioactive than rocks and soils in the surrounding area. 3. A very small area in which to rocks and soils are much more radioactive than the rocks and soils

  10. Airborne radioactivity survey of the West Lonetree area, Uinta county, Wyoming

    USGS Publications Warehouse

    Meuschke, J.L.; Moxham, R.M.

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey in an area of 154 square miles in Uinta county, Wyoming. The survey was made by the U.S. Geological Survey, October 23, 1952, as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation-detection equipment mounted in a Douglas DC-3 aircraft. Parallel traverse lines, spaced at quarter-mile intervals, were flown approximately 500 feet above the ground. Aerial photographs were used for pilot guidance, and the flight path of the aircraft was recorded by a gyro-stabilized, continuous-strip-film camera. The distance of the aircraft from the ground was measured with a continuously recording radio altimeter. At 500 feet above the ground, the width of the zone from which anomalous radioactivity is measured varies with the intensity of radiation of the source and, for strong sources, the width would be as much as 1,400 feet. Quarter-mile spacing of the flight paths of the aircraft should be adequate to detect anomalies from strong sources of radioactivity. However, small areas of considerable radioactivity midway between flight paths may not be noted. The approximate location of each radioactivity anomaly is shown on the accompanying map. The plotted position of an anomaly may be in error by as much as a quarter of a mile owing to errors in the available base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The radioactivity anomaly that is recorded by airborne measurements at 500 feet above the ground can be caused by: 1. A moderately large area in which the rocks and soils are slightly more radioactive than the rocks and soils of the surrounding area. 2. A smaller area in which the rocks and soils are considerably more radioactive than rocks and soils in the surrounding area. 3. A very small area in which to rocks and soils are much more radioactive than the rocks and soils of the surrounding area

  11. Gravity and Magnetic Surveys Over the Santa Rita Fault System, Southeastern Arizona

    USGS Publications Warehouse

    Hegmann, Mary

    2001-01-01

    Gravity and magnetic surveys were performed in the northeast portion of the Santa Rita Experimental Range, in southeastern Arizona, to identify faults and gain a better understanding of the subsurface geology. A total of 234 gravity stations were established, and numerous magnetic data were collected with portable and truck-mounted proton precession magnetometers. In addition, one line of very low frequency electromagnetic data was collected together with magnetic data. Gravity anomalies are used to identify two normal faults that project northward toward a previously identified fault. The gravity data also confirm the location of a second previously interpreted normal fault. Interpretation of magnetic anomaly data indicates the presence of a higher-susceptibility sedimentary unit located beneath lowersusceptibility surficial sediments. Magnetic anomaly data identify a 1-km-wide negative anomaly east of these faults caused by an unknown source and reveal the high variability of susceptibility in the Tertiary intrusive rocks in the area.

  12. Three decades of BGR airborne geophysical surveys over the polar regions - a review

    NASA Astrophysics Data System (ADS)

    Damaske, Detlef

    2013-04-01

    The Federal Institute for Geosciences and Natural Resources (BGR) has been conducting geological polar research since 1979. A few years later BGR engaged in airborne geophysical projects. Investigation of the lithosphere of the continent and the continental margins was one of the key issues for BGR. Right from the beginning geophysical research was closely associated with the geological activities. The GANOVEX (German Antarctic North Victoria Land Expedition) program combined geological research with geophysical (mainly airborne) investigations. This proved to be a fruitful approach to many of the open questions regarding the tectonic development of the Ross Sea region. Aeromagnetic surveys evolved into a powerful tool for identifying geological structures and following them underneath the ice covered areas - not accessible to direct geological investigations. To achieve this aim it was essential to lay out these surveys with a relatively closely spaced line separation on the expense of covering large areas at the same time. Nevertheless, over many years of continues research areas of more than a just regional extent could be covered. This was, however, only possible through international collaboration. During the first years, working in the Ross Sea area, the cooperation with the US and Italian programs played a significant role, especially the GITARA (German-Italian Aeromagnetic Research in Antarctica) program has to be mentioned. GEOMAUD (Geoscientific Expedition to Dronning Maud Land) and the German-Australian joint venture PCMEGA (Prince Charles Mountains Expedition of Germany & Australia) expanded research activities to the East Antarctic shield area. In the International Polar Year (IPY), BGR played a leading role in the international project AGAP (Antarctica's GAmburtsev Province) as part of the main topic "Venture into Unknown Regions". AGAP was jointly conducted by the USA, Great Britain, Australia, China and Germany. While in the Ross Sea area even

  13. A SEA FLOOR GRAVITY SURVEY OF THE SLEIPNER FIELD TO MONITOR CO2 MIGRATION

    SciTech Connect

    Mark Zumberge; Scott Nooner; Glenn Sasagawa

    2004-05-19

    Since 1996, excess CO{sub 2} from the Sleipner natural gas field has been sequestered and injected underground into a porous saline aquifer 1000 m below the seafloor. In 2002, we carried out a high precision micro-gravity survey on the seafloor in order to monitor the injected CO{sub 2}. A repeatability of 5 {micro}Gal in the station averages was observed. This is considerably better than pre-survey expectations. These data will serve as the baseline for time-lapse gravity monitoring of the Sleipner CO{sub 2} injection site. A repeat survey has been scheduled for the summer of 2005. This report covers 9/19/03 to 3/18/04. During this time, significant advancement in the 3-D gravity forward modeling code was made. Testing of the numerical accuracy of the code was undertaken using both a sheet of mass and a frustum of a cone for test cases. These were chosen because of our ability to do an analytic calculation of gravity for comparison. Tests were also done to determine the feasibility of using point mass approximations rather than cuboids for the forward modeling code. After determining that the point mass approximation is sufficient (and over six times faster computationally), several CO{sub 2} models were constructed and the time-lapse gravity signal was calculated from each. From these models, we expect to see a gravity change ranging from 3-16 {micro}Gal/year, depending on reservoir conditions and CO{sub 2} geometry. While more detailed modeling needs to be completed, these initial results show that we may be able to learn a great deal about the state of the CO{sub 2} from the time-lapse gravity results. Also, in December of 2003, we presented at the annual AGU meeting in San Francisco.

  14. Airborne gamma-ray spectrometer and magnetometer survey: Susanville quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Susanville, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1642.8 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  15. Airborne gamma-ray spectrometer and magnetometer survey: Ukiah quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Ukiah, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1517 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  16. Airborne gamma-ray spectrometer and magnetometer survey: Chico quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Chico, California, map area. Traverse lines were flown in an east-west direction at a line spacing of three. Tie lines were flown north-south approximately twelve miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 3026.4 line miles are in the quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  17. Airborne gamma-ray spectrometer and magnetometer survey: Alturas quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Alturas, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1631.6 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  18. Airborne gamma-ray spectrometer and magnetometer survey, Medford Quadrangle Oregon. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Medford, Oregon, map area. Traverse lines were flown in an east-west direction at a line spacing of three miles. Tie lines were flown north-south approximately twelve miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 2925 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  19. Airborne gamma-ray spectrometer and magnetometer survey Coos Bay, Oregon. Final report

    SciTech Connect

    Not Available

    1981-05-01

    During the months of August, September, and October of 1980, Aero Service Division Western Geophysical Company of America conducted an airborne high sensitivity gamma-ray spectrometer and magnetometer survey over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Coos Bay, Oregon, map area. Line spacing was generally six miles for east/west traverses and eighteen miles for north/south tie lines over the northern one-half of the area. Traverses and tie lines were flown at three miles and twelve miles respectively over the southern one-half of the area. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 863.8 line miles are in this quadrangle.

  20. Airborne gamma-ray spectrometer and magnetometer survey, Roseburg Quadrangle, Oregon. Final report

    SciTech Connect

    Not Available

    1981-03-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Roseburg, Oregon, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1596 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  1. Airborne gamma-ray spectrometer and magnetometer survey: Eureka quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Eureka/Crescent City, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were aquired, compiled, and interpreted during the survey, of which 349.5 line miles are in this area. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  2. Relationships between ground and airborne gamma-ray spectrometric survey data, North Ras Millan, Southern Sinai Peninsula, Egypt.

    PubMed

    Youssef, Mohamed A S

    2016-02-01

    In the last decades of years, there was considerable growth in the use of airborne gamma-ray spectrometry. With this growth, there was an increasing need to standardize airborne measurements, so that they can be independent of survey parameters. Acceptable procedures were developed for converting airborne to ground gamma-ray spectrometric measurements of total-count intensity as well as, potassium, equivalent uranium and equivalent thorium concentrations, due to natural sources of radiation. The present study aims mainly to establish relationships between ground and airborne gamma-ray spectrometric data, North Ras Millan, Southern Sinai Peninsula, Egypt. The relationships between airborne and ground gamma-ray spectrometric data were deduced for the original and separated rock units in the study area. Various rocks in the study area, represented by Quaternary Wadi sediments, Cambro-Ordovician sandstones, basic dykes and granites, are shown on the detailed geologic map. The structures are displayed, which located on the detailed geologic map, are compiled from the integration of previous geophysical and surface geological studies. PMID:26650828

  3. Evaluation of low-temperature geothermal potential in Utah and Goshen Valleys and adjacent areas, Utah. Part I. Gravity survey

    SciTech Connect

    Davis, D.A.; Cook, K.L.

    1983-04-01

    During 1980 and 1981 a total of 569 new gravity stations were taken in Utah and Goshen Valleys and adjacent areas, Utah. The new stations were combined with 530 other gravity stations taken in previous surveys which resulted in a compilation of 1099 stations which were used in this study. The additional surveys were undertaken to assist in the evaluation of the area for the possible development of geothermal resources by providing an interpreted structural framework by delineating faults, structural trends, intrusions, thickness of valley fill, and increased density of host rock. The gravity data are presented as (1) a complete Bouguer gravity anomaly map with a 2 mgal contour interval on a scale of 1:100,000 and (2) five generally east-trending gravity profiles. A geologic interpretation of the study area was made from the gravity map and from the interpretive geologic cross sections which were modeled along the gravity profiles.

  4. Vertical wind retrieved by airborne lidar and analysis of island induced gravity waves in combination with numerical models and in situ particle measurements

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Jähn, Michael; Rahm, Stephan; Weinzierl, Bernadett

    2016-04-01

    This study presents the analysis of island induced gravity waves observed by an airborne Doppler wind lidar (DWL) during SALTRACE. First, the instrumental corrections required for the retrieval of high spatial resolution vertical wind measurements from an airborne DWL are presented and the measurement accuracy estimated by means of two different methods. The estimated systematic error is below -0.05 m s-1 for the selected case of study, while the random error lies between 0.1 and 0.16 m s-1 depending on the estimation method. Then, the presented method is applied to two measurement flights during which the presence of island induced gravity waves was detected. The first case corresponds to a research flight conducted on 17 June 2013 in the Cabo Verde islands region, while the second case corresponds to a measurement flight on 26 June 2013 in the Barbados region. The presence of trapped lee waves predicted by the calculated Scorer parameter profiles was confirmed by the lidar and in situ observations. The DWL measurements are used in combination with in situ wind and particle number density measurements, large-eddy simulations (LES), and wavelet analysis to determine the main characteristics of the observed island induced trapped waves.

  5. An interpretation of the 1997 airborne electromagnetic (AEM) survey, Fort Huachuca vicinity, Cochise County, Arizona

    USGS Publications Warehouse

    Bultman, Mark W.; Gettings, Mark E.; Wynn, Jeff

    1999-01-01

    In March of 1997, an airborne electromagnetic (AEM) survey of the Fort Huachuca Military Reservation and immediate surrounds was conducted. This survey was sponsored by the U.S. Army and contracted through the Geologic Division of the U.S. Geological Survey (USGS). Data were gathered by Geoterrex-Dighem Ltd. of Ottawa, Canada. The survey aircraft is surrounded by a coil through which a large current pulse is passed. This pulse induces currents in the Earth which are recorded by a set of three mutually perpendicular coils towed in a "bird" about 100 m behind and below the aircraft. The bird also records the Earth's magnetic field. The system samples the Earth response to the electromagnetic pulse about every 16 m along the aircraft flight path. For this survey, the bulk of the flightpaths were spaced about 400 m apart and oriented in a northeast-southwest direction extending from bedrock over the Huachuca Mountains to bedrock over the Tombstone Hills. A preliminary report on the unprocessed data collected in the field was delivered to the U.S. Army by USGS in July 1997 (USGS Open-File Report 97–457). The final data were delivered in March, 1998 by the contractor to USGS and thence to the U.S. Army. The present report represents the final interpretive report from USGS. The objectives of the survey were to: 1) define the structure of the San Pedro basin in the Sierra Vista-Fort Huachuca-Huachuca City area, including the depth and shape of the basin, and to delineate large faults that may be active within the basin fill and therefore important in the hydrologic regime; 2) define near surface and subsurface areas that contain a large volume fraction of silt and clay in the basin fill and which both reduce the volume of available storage for water and reduce the permeability of the aquifer; and 3) to evaluate the use of the time domain electromagnetic method in the southwest desert setting as a means of mapping depth to water.

  6. Using Precision Gravity Survey To Locate Faults Within The Southern Mesilla Bolson, Rio Grande Rift.

    NASA Astrophysics Data System (ADS)

    Khatun, S.; Doser, D.; Imana, E.

    2003-12-01

    The southern Mesilla bolson of west Texas and southern New Mexico is a rapidly growing portion of the El Paso-Juarez metropolitan area. Faulting within the bolson is difficult to trace due to intensive urban and agricultural activities. Prior to channelization of the Rio Grande in the 1930's the river also frequently altered its course, rapidly depositing or eroding sediment within the bolson, also making the tracing of faults or offset surfaces difficult. We have used the precision gravity technique (digital precision gravity meter, station spacing of 60 m or less, elevation known to 30 cm or less) as an inexpensive method to map possible locations of faults within the bolson. We analyze the gravity data using 3-D modeling techniques that can account for known geology and topography, which are then subtracted from the observed gravity data. The residual gravity map is then examined for sharp gradients and bends in gravity contours that may indicate the presence of faults. Once suspected faults are identified we have conducted follow-up geophysical surveys (DC resistivity sounding, spectral analysis of surface waves) over the structures to determine if grain size or sediment compaction changes (often indicative of faults) are associated with the gravity anomalies. Water well logs have also aided in our interpretations. Our results suggest there are at least 3 faults within the bolson that parallel the range bounding fault that separates the eastern bolson from the western edge of the Franklin Mountains. If these faults are currently seismogenic, they represent a significant hazard to the urban areas located on the thick (1500 m), water saturated sediments of the bolson. We feel the precision gravity technique could serve as a useful reconnaissance tool to help identify faults in other regions where urbanization or other factors limit surface exposure of recent geologic processes.

  7. Gravity Survey of Cavities in Soils - Dangers Involved in Interpretation of Measurements

    NASA Astrophysics Data System (ADS)

    Blecha, V.

    2008-12-01

    Old mine workings, tunnels, cellars, collectors, crypts, sewers, etc. are examples of cavities in soils that can be targets of geophysical surveys. Gravimetry is the principal and often the only method, which may be effectively used in their exploration. Modern digital gravimeters have a resolution of 0.001 mGal, the common mean square error of measurement is usually equal to about ± 0.003 mGal so that an anomaly peak of 0.010 mGal is possible to ascribe to certain geological features. High precision of gravity measurements enables to localize relatively small objects with low density contrast. Consequently, to take advantage of the high precision of gravity data for higher accuracy of geological interpretation means to take into account the gravity effects of objects and features that were often neglected in the past. We measured a gravity profile laid over the rail road tunnel with known parameters. The tunnel with a diameter of 7.4 m is 1758 m long and its roof at the profile line lies at a depth of 14 m. The tunnel was excavated in Tertiary clays, the gravity profile is perpendicular to the tunnel axis and the tunnel portals are at such a distance from the profile that they have no effect on measured gravity values. As emerges from the results of preliminary modeling, the peak of the anomaly caused by the tunnel should be 0.076 mGal. The field measurements show that gravity effect of the tunnel is obscured by a sharp gravity gradient of the regional field. After separation of the field into regional and residual parts we received local negative anomaly with a peak of 0.046 mGal above the tunnel axis. The observed peak of the anomaly is 0.030 mGal lower than that obtained by modeling. The tunnel in the preliminary model was calculated as an empty cavity in homogeneous clays. Successive models show that the difference between the observed gravity values and the preliminary model is caused by gravity effects of tunnel lining, by a zone of deformation that

  8. Airborne electromagnetic surveys in support of groundwater models in western Nebraska

    NASA Astrophysics Data System (ADS)

    Abraham, J. D.; Viezzoli, A.; Cannia, J. C.; Smith, B. D.; Brown, W.; Peterson, S. M.

    2010-12-01

    The USGS, SkyTEM, Aarhus Geophysics, North Platte, South Platte and Twin Platte Natural Resource Districts have collaborated to collect airborne time domain geophysical surveys over selected of areas of western Nebraska. The objective of the surveys was to map the aquifers and bedrock topography of the area to help improve the understanding of groundwater-surface water relations to be used in water management decisions. The base of aquifer in many of these areas is in excess of 100 meters deep and little detailed information of the configuration of the bedrock exits. Many of the aquifers exist as alluvial fills in paleochannels upon complex bedrock topography. Controlling factors for groundwater flow are the variations of the hydraulic properties of the fill and the boundary geometry of the paleochannels. Results from groundwater modeling efforts prior to the addition of the airborne data revealed the hydrogeologic framework was sufficient for the regional scale models, but when these models were reduced to 40 acres cell size, the lack of detail adversely affected model results. The SkyTEM system is a helicopter-borne time-domain electromagnetic system capable of detecting small changes in resistivity from the near-surface down to depths of up to 300 m and is well-suited for aquifer mapping. An innovative design of the receiver coils and transmitter pattern eliminates the self response that is characteristic of airborne systems and spatial measurement sensors mounted on a rigid frame enable rigorous quantitative interpretation of the EM data. The ability to quickly collect and deliver high quality, high resolution geophysical data contributes significantly to modeling efforts and further understanding of subsurface hydrological systems. The raw AEM data have to be edited to exclude data that have been affected by coupling with man made infrastructures. For resistivity data to be related to lithologic information to refine groundwater model inputs, and to make the

  9. Interaction between two adjacent grounded sources in frequency domain semi-airborne electromagnetic survey

    NASA Astrophysics Data System (ADS)

    Zhou, Haigen; Lin, Jun; Liu, Changsheng; Kang, Lili; Li, Gang; Zeng, Xinsen

    2016-03-01

    Multi-source and multi-frequency emission method can make full use of the valuable and short flight time in frequency domain semi-airborne electromagnetic (FSAEM) exploration, which has potential to investigate the deep earth structure in complex terrain region. Because several sources are adjacent in multi-source emission method, the interaction of different sources should be considered carefully. An equivalent circuit model of dual-source is established in this paper to assess the interaction between two individual sources, where the parameters are given with the typical values based on the practical instrument system and its application. By simulating the output current of two sources in different cases, the influence from the adjacent source is observed clearly. The current waveforms show that the mutual resistance causes the fluctuation and drift in another source and that the mutual inductance causes transient peaks. A field test with dual-source was conducted to certify the existence of interaction between adjacent sources. The simulation of output current also shows that current errors at low frequency are mainly caused by the mutual resistance while those at high frequency are mainly due to the mutual inductance. Increasing the distance between neighboring sources is a proposed measure to reduce the emission signal errors with designed ones. The feasible distance is discussed in the end. This study gives a useful guidance to lay multi sources to meet the requirement of measurement accuracy in FSAEM survey.

  10. Interaction between two adjacent grounded sources in frequency domain semi-airborne electromagnetic survey.

    PubMed

    Zhou, Haigen; Lin, Jun; Liu, Changsheng; Kang, Lili; Li, Gang; Zeng, Xinsen

    2016-03-01

    Multi-source and multi-frequency emission method can make full use of the valuable and short flight time in frequency domain semi-airborne electromagnetic (FSAEM) exploration, which has potential to investigate the deep earth structure in complex terrain region. Because several sources are adjacent in multi-source emission method, the interaction of different sources should be considered carefully. An equivalent circuit model of dual-source is established in this paper to assess the interaction between two individual sources, where the parameters are given with the typical values based on the practical instrument system and its application. By simulating the output current of two sources in different cases, the influence from the adjacent source is observed clearly. The current waveforms show that the mutual resistance causes the fluctuation and drift in another source and that the mutual inductance causes transient peaks. A field test with dual-source was conducted to certify the existence of interaction between adjacent sources. The simulation of output current also shows that current errors at low frequency are mainly caused by the mutual resistance while those at high frequency are mainly due to the mutual inductance. Increasing the distance between neighboring sources is a proposed measure to reduce the emission signal errors with designed ones. The feasible distance is discussed in the end. This study gives a useful guidance to lay multi sources to meet the requirement of measurement accuracy in FSAEM survey. PMID:27036795

  11. The U.S. Geological Survey side-looking airborne radar database: an aid to the interpretation of space images

    USGS Publications Warehouse

    Kover, Allan N.; Schoonmaker, James W.

    1993-01-01

    The U.S. Geological Survey (USGS) has a database of side-looking airborne radar (SLAR) images of a significant part of the continental United States. These images provide a regional view of terrains and should be an aid to better understanding image data of satellite synthetic aperture radar (SAR) and other systems. The USGS has been systematically collecting SLAR since 1980, initially in analog form, then in both analog and digital format since 1984.

  12. Airborne Gravimetry: Data Accuracy Evaluated for use in Geoid Calculation

    NASA Astrophysics Data System (ADS)

    Childers, V. A.; Holmes, S. A.; Preaux, S. A.

    2012-12-01

    NOAA's National Geodetic Survey (NGS) has launched the Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Project as a means of replacing the US national vertical datum with a gravimetric geoid by 2022. To produce the gravity field needed for our geoid, we will blend airborne gravity data collected by the GRAV-D project with long wavelength gravity fields from the GRACE and GOCE satellites and with short wavelength information from surface (terrestrial and marine) holdings and predicted gravity from topography when surface data are too sparse. The question remains: what is the waveband of reliable airborne data from a beam-style gravimeter flown at high altitude (20,000 ft) given the challenges presented by varying aircraft motion in different aircraft and different weather conditions? This presentation will focus upon known error sources in the airborne data (e.g. off-level errors, filtering, IMU-GPS tightly coupled vs GPS-only solutions) and provide analysis of their spectral signatures through comparison with EGM08 and GOCO03S. The result of this study is a recommendation for the waveband of reliability for GRAV-D-style airborne gravity data to best enhance high-accuracy harmonic geoid modeling.

  13. 3. Neural changes in different gravity and ecophysiological environments - A survey

    NASA Astrophysics Data System (ADS)

    Slenzka, K.

    Neural changes or neuronal plasticity occur after and during different stimulations and inputs in general. Gravity is one major input to the brain transferred from the vestibular system. However, often also direct effects of gravity on the cellular level are discussed. Our group was investigating the influence of different gravity environments on a large variety of neuronal enzymes in the developing fish brain. Long-term space travel or bases on Moon and Mars will have to deal not only with neural changes based on the different gravity environment, but also with potential negative or even toxic changes in the respective life support system. Our goal is now to identify reported enzyme activity changes in the brain based for example on potential toxic drugs or endocrine disruptors in combination with gravity induced changes. In this paper a survey will be undertaken discussing recent results obtained in ecotoxicology, gravitational biology combined with new data from our group regarding potential differences in brain glucose-6-phosphate dehydrogenase of medaka and zebrafish.

  14. A SEA FLOOR GRAVITY SURVEY OF THE SLEIPNER FIELD TO MONITOR CO2 MIGRATION

    SciTech Connect

    Mark Zumberge; Scott Nooner

    2005-07-11

    Since 1996, excess CO{sub 2} from the Sleipner natural gas field has been sequestered and injected underground into a porous saline aquifer 1000 m below the seafloor. In 2002, we carried out a high precision micro-gravity survey on the seafloor in order to monitor the injected CO{sub 2}. A repeatability of 5 {micro}Gal in the station averages was observed. This is considerably better than pre-survey expectations. These data will serve as the baseline for time-lapse gravity monitoring of the Sleipner CO{sub 2} injection site. A repeat survey has been scheduled for the summer of 2005. This report covers 9/19/04 to 3/18/05. During this time, gravity and pressure modeling were completed and work graduate student Scott Nooner began writing his Ph.D. dissertation, of which this work is a the major part. Improvements to the gravimeters are also underway that will hopefully increase the measurement precision.

  15. A SEA FLOOR GRAVITY SURVEY OF THE SLEIPNER FIELD TO MONITOR CO2 MIGRATION

    SciTech Connect

    Mark Zumberge; Scott Nooner; Ola Eiken

    2004-11-29

    Since 1996, excess CO{sub 2} from the Sleipner natural gas field has been sequestered and injected underground into a porous saline aquifer 1000 m below the seafloor. In 2002, we carried out a high precision micro-gravity survey on the seafloor in order to monitor the injected CO{sub 2}. A repeatability of 5 {micro}Gal in the station averages was observed. This is considerably better than pre-survey expectations. These data will serve as the baseline for time-lapse gravity monitoring of the Sleipner CO{sub 2} injection site. A repeat survey has been scheduled for the summer of 2005. This report covers 3/18/04 to 9/19/04. During this time, we participated in several CO{sub 2} sequestration-related meetings and conferences. On March 29, 2004, we participated in the 2004 Carbon Sequestration Project Review Meeting for the Department of Energy in Pittsburgh, PA. During the week of May 2, 2004, we attended and presented at the Third Annual Conference on Carbon Capture and Sequestration in Alexandria, VA. Finally, during the week of August 8, 2004, we took part in the U.S.-Norway, CO{sub 2} Summer School in Santa Fe, NM. Additional modeling was also completed, examining the seismic velocity pushdown estimates from the gravity models and the expected deformation of the seafloor due to the injected CO{sub 2}.

  16. The XMM Cluster Survey: testing chameleon gravity using the profiles of clusters

    NASA Astrophysics Data System (ADS)

    Wilcox, Harry; Bacon, David; Nichol, Robert C.; Rooney, Philip J.; Terukina, Ayumu; Romer, A. Kathy; Koyama, Kazuya; Zhao, Gong-Bo; Hood, Ross; Mann, Robert G.; Hilton, Matt; Manolopoulou, Maria; Sahlén, Martin; Collins, Chris A.; Liddle, Andrew R.; Mayers, Julian A.; Mehrtens, Nicola; Miller, Christopher J.; Stott, John P.; Viana, Pedro T. P.

    2015-09-01

    The chameleon gravity model postulates the existence of a scalar field that couples with matter to mediate a fifth force. If it exists, this fifth force would influence the hot X-ray emitting gas filling the potential wells of galaxy clusters. However, it would not influence the clusters weak lensing signal. Therefore, by comparing X-ray and weak lensing profiles, one can place upper limits on the strength of a fifth force. This technique has been attempted before using a single, nearby cluster (Coma, z = 0.02). Here we apply the technique to the stacked profiles of 58 clusters at higher redshifts (0.1 < z < 1.2), including 12 new to the literature, using X-ray data from the XMM Cluster Survey and weak lensing data from the Canada-France-Hawaii-Telescope Lensing Survey. Using a multiparameter Markov chain Monte Carlo analysis, we constrain the two chameleon gravity parameters (β and φ∞). Our fits are consistent with general relativity, not requiring a fifth force. In the special case of f(R) gravity (where β = √{1/6}), we set an upper limit on the background field amplitude today of |fR0| < 6 × 10-5 (95 per cent CL). This is one of the strongest constraints to date on |fR0| on cosmological scales. We hope to improve this constraint in future by extending the study to hundreds of clusters using data from the Dark Energy Survey.

  17. A SEA FLOOR GRAVITY SURVEY OF THE SLEIPNER FIELD TO MONITOR CO2 MIGRATION

    SciTech Connect

    Mark Zuberge; Scott Nooner; Glenn Sasagawa

    2003-11-17

    Since 1996, excess CO{sub 2} from the Sleipner natural gas field has been sequestered and injected underground into a porous saline aquifer 1000 m below the seafloor. In 2002, we carried out a high precision micro-gravity survey on the seafloor in order to monitor the injected CO{sub 2}. A repeatability of 5 {micro}Gal in the station averages was observed. This is considerably better than pre-survey expectations. These data will serve as the baseline for time-lapse gravity monitoring of the Sleipner CO{sub 2} injection site. A three-week trip to Statoil Research Centre in Trondheim, Norway, was made in the summer of 2003. This visit consisted of gathering data and collaborating with scientists working on the Sleipner project. The trip ended with a presentation of the seafloor gravity results to date at a SACS2 (Saline Aquifer CO{sub 2} Storage 2) meeting. This meeting provided the perfect opportunity to meet and gather information from the world's experts on the Sleipner project.

  18. Airborne Geophysical Surveys Illuminate the Geologic and Hydrothermal Framework of the Pilgrim Springs Geothermal Area, Alaska

    NASA Astrophysics Data System (ADS)

    McPhee, D. K.; Glen, J. M.; Bedrosian, P. A.

    2012-12-01

    An airborne magnetic and frequency-domain electromagnetic (EM) survey of the Pilgrim Springs geothermal area, located on the Seward Peninsula in west-central Alaska, delineates key structures controlling hydrothermal fluid flow. Hot springs, nearby thawed regions, and high lake temperatures are indicative of high heat flow in the region that is thought to be related to recent volcanism. By providing a region-wide geologic and geophysical framework, this work will provide informed decisions regarding drill-site planning and further our understanding of geothermal systems in active extensional basins. Helicopter magnetic and EM data were acquired using a Fugro RESOLVE system equipped with a high sensitivity cesium magnetometer and a multi-coil, multi-frequency EM system sensitive to the frequency range of 400-140,000 Hz. The survey was flown ~40 m above ground along flight lines spaced 0.2-0.4 km apart. Various derivative and filtering methods, including maximum horizontal gradient of the pseudogravity transformation of the magnetic data, are used to locate faults, contacts, and structural domains. A dominant northwest trending anomaly pattern characterizes the northeastern portion of the survey area between Pilgrim Springs and Hen and Chickens Mountain and may reflect basement structures. The area south of the springs, however, is dominantly characterized by east-west trending, range-front-parallel anomalies likely caused by late Cenozoic structures associated with the north-south extension that formed the basin. Regionally, the springs are characterized by a magnetic high punctuated by several east-west trending magnetic lows, the most prominent occurring directly over the springs. The lows may result from demagnetization of magnetic material along range-front parallel features that dissect the basin. We inverted in-phase and quadrature EM data along each profile using the laterally-constrained inversion of Auken et al. (2005). Data were inverted for 20-layer

  19. Airborne geophysical survey of ice caps in the Queen Elizabeth Islands, Arctic Canada

    NASA Astrophysics Data System (ADS)

    Palmer, S. J.; Dowdeswell, J. A.; Christoffersen, P.; Benham, T. J.; Young, D. A.; Blankenship, D. D.; Richter, T.; Ng, G.; Grima, C.; Habbal, F.; Sharp, M. J.; Rutishauser, A.

    2014-12-01

    Previous studies have shown that between 2003 and 2009, 60 ± 6 Gt of ice was lost each year from the Canadian Arctic (Gardner et al., 2013), making the region the largest cryospheric contributor to global sea level rise outside of the great ice sheets. Glacier ice in the Queen Elizabeth Islands (QEI) currently covers more than 100,000 km2, representing 20% of Earth's ice-covered land area outside of Greenland and Antarctica. The vast majority of this ice is stored within six ice caps located on Ellesmere, Devon and Axel Heiberg islands. Recent satellite observations of the outlet glaciers draining these ice caps have revealed significant velocity variability on inter-annual and multi-year timescales (Van Wychen et al., 2014), though the drivers of these dynamics are not yet understood. Here we present results obtained in May 2014 during an airborne geophysical survey of the ice caps of Axel Heiberg, Ellesmere and Devon islands, including Agassiz Ice Cap (17,300 km2), Prince of Wales Icefield (19,300 km2) and Devon Ice Cap (14,000 km2). We used a Basler BT-67 aircraft equipped with a suite of geophysical instruments, including a phase-coherent VHF ice-penetrating radar, to measure ice thickness and investigate ice basal conditions along outlet glacier flow lines and in the interior of the ice caps. We reveal that the glaciers draining the ice caps of the QEI exhibit diverse characteristics over short spatial scales, and that fast-flowing tidewater glaciers are located adjacent to previously fast-flowing areas that have subsequently stagnated. Our results show that many ice cap outlet glaciers on Ellesmere and Devon islands are between 700 and 1000 m thick and flow through deep bedrock troughs whose beds lie below sea-level. Some of the outlet glaciers also have floating tongues of ice which extend into the adjacent fjord waters. We intend to use our results to characterize the substrate beneath the ice, and to reveal any variations in conditions at the ice

  20. Using remote sensing and ancillary data to extend airborne electromagnetic resistivity surveys for regional permafrost interpretation

    NASA Astrophysics Data System (ADS)

    Pastick, N.; Wylie, B. K.; Minsley, B. J.; Jorgenson, T. T.; Ji, L.; Walvoord, M. A.; Smith, B. D.; Abraham, J. D.; Rose, J.

    2011-12-01

    Permafrost has a significant impact on high latitude ecosystems and is spatially heterogeneous. However, only generalized maps of permafrost extent are available. Due to its impacts on subsurface hydrology, lake water levels, vegetation communities, and surface soil deformations, understanding the spatial extents and depth of permafrost are critical. Electrical resistivity increases dramatically as a soil freezes and can be used as a proxy for permafrost presence particularly if the underlying soils and geologic characteristics are understood. An airborne electromagnetic survey (AEM) was conducted over a portion of the Yukon Flats ecoregion in central Alaska with measurements taken in both reconnaissance lines and contiguous block area coverage. The AEM was flown in June 2010 and subsurface resistivity models were derived by inverting the AEM data. Landsat TM at-sensor reflectance, thermal, and spectral index data from late August to early September 2008, Digital Elevation Models (DEM) and derivatives, and other ancillary data were used in a regression tree model to predict near surface electrical resistivity at the 0-1m and the 0-2.6m depth intervals. AEM locations from homogenous landsat 90 m by 90 m windows were randomly separated into a training set for model development (n = 8,848) and an impendent test data set (n = 988) for model accuracy assessment. Model development and independent test accuracies for 0-1 m electric resistivity had training and test R2 values of 0.90 and 0.87, respectively, and for the 0-2.6m electric resistivity training and test R2 values were also 0.90 and 0.87, respectively, which indicated accurate prediction models. Important variables for stratifying the various piecewise regressions were elevation and averaged 2000-2008 ecosystem performance anomalies. Important independent variables used in the multiple regression equations were the Normalized Difference Infrared Index (NDII), NDII7 (NDII using band 7), soil moisture mapped from

  1. Elevation and mass balance changes in Alaska glaciers from airborne LiDAR surveys

    NASA Astrophysics Data System (ADS)

    Murphy, Nathaniel; Larsen, Chris; Johnson, Austin

    2013-04-01

    Since 1993, the University of Alaska (UAF) Glaciers Group has monitored glacier elevation changes across Alaska (AK) and northwest Canada (NWC) using airborne laser altimetry surveys. Since 2009, this effort has been part of NASA's Operation Ice Bridge. The ongoing campaign has measured centerline elevation profiles for over 200 glaciers in the region. We will present updated mass balance and volume change estimates of glaciers and ice fields throughout AK and NWC. In addition, we estimate the contribution to sea level rise (SLR) from AK and NWC glaciers. In 2009 the single-point laser altimeter was replaced by a scanning LiDAR system, which vastly improves the sampling rate and spatial coverage of the laser returns. The combination of updated glacier outlines, upgraded LiDAR system, and improved analysis techniques provides more accurate results and more robust uncertainty analysis of the glacier mass balances and SLR calculations. Our recent results suggest that AK and NWC glaciers overall continue to show loss of surface elevation and decreasing mass balances. AK and NWC glaciers show high variability in the relationships between mass balances and glacier-type, geographic distribution, and climate. In Denali National Park, most of the surveyed glaciers show negative mass balances increasing by approximately 50% from about -0.7 m/yr w.e. to -1.2 m/yr w.e. Mountain glaciers in Lake Clark National Park followed similar trends of slightly positive mass balances from 1996-2001 (~0.2 m/yr w.e.),and slightly negative mass balances from 2001-2008 (~ -0.6 m/yr w.e.). In the Juneau Icefield, Taku Glacier has maintained positive mass balances in recent decades, but from 2007 to 2011 its mass balance decreased to values of zero to slightly negative (-0.1 ± 0.1 m/yr w.e.). This decrease in the mass balance of Taku Glacier appears to be driven by loss of surface elevations in the upper areas of the glacier. The mass balances of glaciers in Glacier Bay National Park generally

  2. Preliminary analysis of gravity and aeromagnetic surveys of the Timber Mountain Area, southern Nevada

    SciTech Connect

    Kane, M.F.; Webring, M.W.; Bhattacharyya, B.K.

    1981-12-31

    Recent (1977 to 1978) gravity and aeromagnetic surveys of the Timber Mountain region, southern Nevada, have revealed new details of subsurface structure and lithology. The data strongly suggest that deformation caused by volcanic events has been accommodated along straight-line faults combining in such a fashion as to given a curvilinear appearance to regional structure. The magnetic data suggest that rock units in the central graben and along the southeast margin of Timber Mountain may have been altered, perhaps thermally, from their original state. The gravity data indicate that the south part of the Timber Mountain is underlain by relatively dense rock possibly intrusive rock, like that which crops out along its southeast side. The gravity data also suggest that the Silent Canyon caldera may extend considerably south of its presently indicated southern limit and may underlie much of the area of Timber Mountain. The moat areas appear to be more rectangular or triangular than annular in shape. The southern part of Timber Mountain caldera is separated from the Yucca Mountain area to the south by a triangular horst. The structural relations of the rock units making up the horst are complex. Several linear terrain features in the southern part of the caldera area are closely aligned with geophysical features, implying that the terrain features are fault-controlled.

  3. Influence of gravity field uncertainties on the results from POGO and Magsat geomagnetic surveys

    NASA Technical Reports Server (NTRS)

    Taylor, P. T.; Langel, R. A.; Kahn, W. D.; Schanzle, A. F.; Jones, T. L.

    1981-01-01

    Errors in the gravity models used in satellite position calculations are examined as a possible source of the 0 to 100% variance found between POGO and Magsat magnetic data and the extrapolations of aerial magnetic survey data to satellite heights. For POGO data obtained over the New York Bight region using a relatively poor gravity field (a hybrid spherical harmonic model of degree 7 and order 6 with three higher order resonance terms), the magnitude of the error in the satellite height component is found to be sufficient to account for the amplitude of the discrepancy, however the frequency of the quasi-periodic orbital error is too large to explain the localized nature of the differences. For the case of the Magsat satellite, in which a more accurate gravity model was used, it is found that a 30 mgal gravitational anomaly distributed over a 5 x 5 deg area will produce insufficiently large position errors to account for the variations. The agreement between the two sets of satellite data in the New York Bight region suggests either a consistent error in satellite measurements, or problems with the reduction and processing of the aeromagnetic data.

  4. Extensive survey of molecules related to wood formation and gravity for space agriculture.

    NASA Astrophysics Data System (ADS)

    Motohashi, Kyohei; Tomita-Yokotani, Kaori; Baba, Keiichi; Furukawa, Jun; Sato, Seigo; Suzuki, Toshisada; Hashimoto, Hirofumi; Yamashita, Masamichi; Japanese Space Tree Working Group

    Most, if not all, terrestrial subjects are under the influence of gravity. Since the gravitational force is proportional to the mass of subject, gravity is dominant for larger masses. The response of a plant against gravity is not an exception in this respect even it shows rather complicated features. For the angiosperm tree, its shape is determined by the forming tension wood, which induces more tensile stress in the xylem than in the normal wood. The mechanism of tension wood formation and its relevance to gravity have been extensively studied. Gibberellin is known to be responsible for this phenomenon in angiosperm tree, for example, the Japanese cherry tree, Prunus jamasakura. However, full understanding of the mechanisms has not yet been clarified. For an extensive survey of molecules related to tension wood formation, we induced an artificial tension wood formation and examined the tension wood formation by microscopic observations with double-staining. This enables the screening of really functional molecules in the space environment for future space agriculture. We demonstrated that Prunus incise is suitable for this research as a test material based on several reasons. We focused our attention in the region of the branch, i.e., the CosmoTree in CosmoBon, and established an experimental system to analyze the real functional factors of the tension wood. This study might ensure wood formation in a space environment and use woody plants as a material for space development. ("CosmoBon" is the Bonsai small tree for our space experiments. "CosmoTree" is a small branch/tree.)

  5. Exploring Liquid Water Beneath Glaciers and Permafrost in Antarctica Through Airborne Electromagnetic Surveys

    NASA Astrophysics Data System (ADS)

    Auken, E.; Tulaczyk, S. M.; Foley, N.; Dugan, H.; Schamper, C.; Peter, D.; Virginia, R. A.; Sørensen, K.

    2015-12-01

    Here, we demonstrate how high powered airborne electromagnetic resistivity is efficiently used to map 3D domains of unfrozen water below glaciers and permafrost in the cold regions of the Earth. Exploration in these parts of the world has typically been conducted using radar methods, either ground-based or from an airborne platform. Radar is an excellent method if the penetrated material has a low electrical conductivity, but in materials with higher conductivity, such as sediments with liquid water, the energy is attenuated . Such cases are efficiently explored with electromagnetic methods, which attenuate less quickly in conductive media and can therefore 'see through' conductors and return valuable information about their electrical properties. In 2011, we used a helicopter-borne, time-domain electromagnetic sensor to map resistivity in the subsurface across the McMurdo Dry Valleys (MDV). The MDV are a polar desert in coastal Antarctica where glaciers, permafrost, ice-covered lakes, and ephemeral summer streams coexist. In polar environments, this airborne electromagnetic system excels at finding subsurface liquid water, as water which remains liquid under cold conditions must be sufficiently saline, and therefore electrically conductive. In Taylor Valley, in the MDV, our data show extensive subsurface low resistivity layers beneath higher resistivity layers, which we interpret as cryoconcentrated hypersaline brines lying beneath glaciers and frozen permafrost. These brines appear to be contiguous with surface lakes, subglacial regions, and the Ross Sea, which could indicate a regional hydrogeologic system wherein solutes may be transported between surface reservoirs by ionic diffusion and subsurface flow. The system as of 2011 had a maximum exploration depth of about 300 m. However, newer and more powerful airborne systems can explore to a depth of 500 - 600 m and new ground based instruments will get to 1000 m. This is sufficient to penetrate to the base of

  6. Gravity survey in part of the Snake River Plain, Idaho - a preliminary report

    USGS Publications Warehouse

    Baldwin, Harry L.; Hill, David P.

    1960-01-01

    During the early summer of 1959, a total of 1,187 gravity stations were occupied on the western part of the Snake River plain in Idaho. An area of 2,000 square miles extending from Glenns Ferry, Idaho, to Caldwell, Idaho, was covered with a station density of one station per two square miles. An additional 1,200 square miles of surrounding area, mainly from Caldwell, Idaho, to the Oregon-Idaho state line, was covered with a density of one station per seven square miles. The mean reproducibility of the observed gravities of these stations was 0.05 milligal, with a maximum discrepancy of 0.2 milligal. Gravity data were reduced to simple Bouguer values using a combined free-air and Bouguer correction of 0.06 milligal per foot. The only anomalies found with closure in excess of 10 milligals are two elongated highs, orientated northwest-southeast, with the northwestern high offset to the northeast by 10 miles. The smaller of these highs extends from Meridian, Idaho, to Nyssa, Oregon, and the larger extends from Swan Falls, Idaho, to Glenns Ferry, Idaho. The maximum value recorded is a simple Bouguer value of -66.5 milligals with respect to the International Ellipsoid. Gradients on the sides of these highs are largest on the northeast sides, reaching six milligals per mile in places. Graticule interpretations of a profile across the southeastern high using a density contrast of 0.3 gm per cubic centimeter indicate an accumulation of lava reaching a thickness of at least 28,000 feet. The Snake River investigation was made for the purpose of searching out, defining, and interpreting gravity anomalies present on the western part of the Snake River lava plain in Idaho. In particular, it was desired to further define gradients associated with the gravity high shown by the regional work of Bonini and Lavin (1957). It was not planned to cover any specific area, but rather to let the observed anomalies determine the course of the field work. The study was undertaken as part of a

  7. International Symposium on Airborne Geophysics

    NASA Astrophysics Data System (ADS)

    Mogi, Toru; Ito, Hisatoshi; Kaieda, Hideshi; Kusunoki, Kenichiro; Saltus, Richard W.; Fitterman, David V.; Okuma, Shigeo; Nakatsuka, Tadashi

    2006-05-01

    Airborne geophysics can be defined as the measurement of Earth properties from sensors in the sky. The airborne measurement platform is usually a traditional fixed-wing airplane or helicopter, but could also include lighter-than-air craft, unmanned drones, or other specialty craft. The earliest history of airborne geophysics includes kite and hot-air balloon experiments. However, modern airborne geophysics dates from the mid-1940s when military submarine-hunting magnetometers were first used to map variations in the Earth's magnetic field. The current gamut of airborne geophysical techniques spans a broad range, including potential fields (both gravity and magnetics), electromagnetics (EM), radiometrics, spectral imaging, and thermal imaging.

  8. Comparison of Precision of Biomass Estimates in Regional Field Sample Surveys and Airborne LiDAR-Assisted Surveys in Hedmark County, Norway

    NASA Technical Reports Server (NTRS)

    Naesset, Erik; Gobakken, Terje; Bollandsas, Ole Martin; Gregoire, Timothy G.; Nelson, Ross; Stahl, Goeran

    2013-01-01

    Airborne scanning LiDAR (Light Detection and Ranging) has emerged as a promising tool to provide auxiliary data for sample surveys aiming at estimation of above-ground tree biomass (AGB), with potential applications in REDD forest monitoring. For larger geographical regions such as counties, states or nations, it is not feasible to collect airborne LiDAR data continuously ("wall-to-wall") over the entire area of interest. Two-stage cluster survey designs have therefore been demonstrated by which LiDAR data are collected along selected individual flight-lines treated as clusters and with ground plots sampled along these LiDAR swaths. Recently, analytical AGB estimators and associated variance estimators that quantify the sampling variability have been proposed. Empirical studies employing these estimators have shown a seemingly equal or even larger uncertainty of the AGB estimates obtained with extensive use of LiDAR data to support the estimation as compared to pure field-based estimates employing estimators appropriate under simple random sampling (SRS). However, comparison of uncertainty estimates under SRS and sophisticated two-stage designs is complicated by large differences in the designs and assumptions. In this study, probability-based principles to estimation and inference were followed. We assumed designs of a field sample and a LiDAR-assisted survey of Hedmark County (HC) (27,390 km2), Norway, considered to be more comparable than those assumed in previous studies. The field sample consisted of 659 systematically distributed National Forest Inventory (NFI) plots and the airborne scanning LiDAR data were collected along 53 parallel flight-lines flown over the NFI plots. We compared AGB estimates based on the field survey only assuming SRS against corresponding estimates assuming two-phase (double) sampling with LiDAR and employing model-assisted estimators. We also compared AGB estimates based on the field survey only assuming two-stage sampling (the NFI

  9. Elemental composition of airborne particulates and source identification - An extensive one year survey. [in Cleveland, OH

    NASA Technical Reports Server (NTRS)

    King, R. B.; Fordyce, J. S.; Antoine, A. C.; Leibecki, H. F.; Neustadter, H. E.; Sidik, S. M.

    1976-01-01

    Concentrations of 60 chemical elements in the airborne particulate matter were measured at 16 sites in Cleveland, OH over a 1 year period during 1971 and 1972 (45 to 50 sampling days). Analytical methods used included instrumental neutron activation, emission spectroscopy, and combustion techniques. Uncertainties in the concentrations associated with the sampling procedures, the analytical methods, the use of several analytical facilities, and samples with concentrations below the detection limits are evaluated in detail. The data are discussed in relation to other studies and source origins. The trace constituent concentrations as a function of wind direction are used to suggest a practical method for air pollution source identification.

  10. Borehole gravity meter survey in drill hole USW G-4, Yucca Mountain Area, Nye County, Nevada

    SciTech Connect

    Healey, D.L.; Clutsom, F.G.; Glover, D.A.

    1986-12-31

    Drill hole USW G-4 was logged with the US Geological Survey borehole gravity meter (BHGM) BH-6 as part of a detailed study of the lithostratigraphic units penetrated by this hole. Because the BHGM measures a larger volume of rock than the conventional gamma-gamma density tool, it provides an independent and more accurate measurement of the in situ average bulk density of thick lithologic units. USW G-4 is an especially important hole because of its proximity to the proposed exploratory shaft at Yucca Mountain. The BHGM data were reduced to interval densities using a free-air gradient (F) of 0.3083 mGal./m (0.09397 mGal/ft) measured at the drill site. The interval densities were further improved by employing an instrument correction factor of 1.00226. This factor was determined from measurements obtained by taking gravity meter BH-6 over the Charleston Peak calibration loop. The interval density data reported herein, should be helpful for planning the construction of the proposed shaft.

  11. Optimizing cosmic shear surveys to measure modifications to gravity on cosmic scales

    NASA Astrophysics Data System (ADS)

    Kirk, Donnacha; Laszlo, Istvan; Bridle, Sarah; Bean, Rachel

    2013-03-01

    We consider how upcoming photometric large-scale structure surveys can be optimized to measure the properties of dark energy (DE) and possible cosmic-scale modifications to General Relativity in light of realistic astrophysical and instrumental systematic uncertainties. In particular, we include flexible descriptions of intrinsic alignments (IAs), galaxy bias and photometric redshift uncertainties in a Fisher Matrix analysis of shear, position and position-shear correlations, including complementary cosmological constraints from the cosmic microwave background. We study the impact of survey trade-offs in depth versus breadth, and redshift quality. We parametrize the results in terms of the Dark Energy Task Force figure of merit, and deviations from General Relativity through an analogous modified gravity (MG) figure of merit. We find that IAs weaken the dependence of figure of merit on area and that, for a fixed observing time, halving the area of a Stage IV reduces the figure of merit by 20 per cent when IAs are not included and by only 10 per cent when IAs are included. While reducing photometric redshift scatter improves constraining power, the dependence is shallow. The variation in constraining power is stronger once IAs are included and is slightly more pronounced for MG constraints than for DE. The inclusion of IAs and galaxy position information reduces the required prior on photometric redshift accuracy by an order of magnitude for both the fiducial Stage III and IV surveys, equivalent to a factor of 100 reduction in the number of spectroscopic galaxies required to calibrate the photometric sample.

  12. The ancient harbour system of Terracina (Latium, Italy) obtained by gravity survey.

    NASA Astrophysics Data System (ADS)

    di Nezza, M.; di Filippo, M.

    2009-04-01

    Historical research has shown that Terracina (Latina, Latium) played a fundamental role in the maritime and land traffic since before the foundation of the colony. The settlement was established where the organized system of maritime, land, coastal, and fluvial transport had the most ideal conditions to constitute an important commercial crossroads, apparently since the beginning of recorded history. In order to reconstruction the buried archaeological structures attributed to the ancient Roman port, traditionally attributed to Traiano, in the current area of the harbour of Terracina, it was carried out a gravity survey, more than 380 gravity stations. This method enables to recognize the cavity and the structures of the buildings underground through the results of variations density in the subsoil. In the residual gravity anomaly map a series of positive anomalies are visible which confirm the round structures and the pier of the buried foundations of the Imperial harbour. Unfortunately, little remains of the functioning facilities of the harbour's activities. The modern construction of the harbour, in fact, has to be developed around the new inhabitable commercial area, know today as Terracina Bassa or Borgo alla Marina. It had to be developed with a modern infrastructure of a harbor area, as in the construction of the rooms for storage of goods, warehouses, as well as for the thermal baths, hotels and amphitheatre. Furthermore, there are always the positive anomalies that characterize the area to the north-east of "Montone" hill where archaeological remains are easily visible near Via Lungolinea Pio VI. A large negative anomaly is situated in correspondence with "Montone". Gravity information shows an average density of the hill approximately 1.10 g/cm3, notably less than the recorded data relative to dry sand, approximately 1.6 g/cm3. The low value founds hits at the possibility of an "emptiness" in the subsoil of "Montone" hill, attribuiting to the possible

  13. The Application of Gravity and CSAMT Survey on Baishan Molybdenum Deposit, Hami, Xinjiang,China

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Lu, H.; Zhang, K.

    2014-12-01

    Baishan molybdenum deposit is located in the eastern Tianshan Carboniferous rift at Hami, Xinjiang, China, where exposed upper Carboniferous Gandun formation. Molybdenum ore appeared at thermal contact metamorphism hornfelsed banded quartz stockwork in the concealed porphyritic granite top, Potassium and metal sulfide mineralization existed in the top of concealed rockbody.The Baishan molybdenum ore bodies were delineated 2700 meters long and 40 meters thickness, with molybdenum @ 0.59%. The main orebody shows in stratoid, small orebody appears in lenticular and vein.In order to predict potential resources, we proposes a combined method of CSAMT and GS technology,and has applied it to the survey of concealed molybdenum deposit in the Baishan.This combind method can explore to larger depths, discriminate anomalies well and has higher resolution to deep objects, thus it is an efficient tool for surveys.By drilling, we found there exsit a hidden granite body in 1400 meters deep of Hami Baishan molybdenum mine, it confirmed that Baishan molybdenum mine is a porphyry molybdenum ore. Cataclastic hornfelsed zone in the coping granite are the product of heat contact metamorphism, the ore materials are mainly derived from deep magma hydrothermal solution. The CSAMT and Gravity Survey were able to reflect the space and intrusive boundary in rough of buried granite body clearly, deep hidden granite showed high-resistivity and high-gravity anomaly and the low-resistivity anomaly distributied around them, drilling verified that 200-2500Ω low-resistivity anomaly range at top of high-resistivity corresponded to the molybdenum ore horizon. Line 15 of southern section shows two low resistance anomaly zone, and the surface of them is corresponding to the granite and intrusive contact parts,inferring it was caused by the fault structure.In granite gravity anomaly is obviously high and the width is about 560m,Δg residual value is 400 × 10-8m/s2. According to the control of

  14. Development of a laser fluorosensor for airborne surveying of the aquatic environment

    NASA Technical Reports Server (NTRS)

    Bristow, M. P. F.; Houston, W. R.; Measures, R. M.

    1975-01-01

    A field based laser fluorosensor, employing a pulsed nitrogen laser and telescope photomultiplier detector system, has been successfully tested at night from a cliff top site overlooking Lake Ontario providing target ranges greater than 274 meters. Remotely sensed spectra and amplitude changes in the fluorescence emission of natural waters have shown potential as a water quality indicator. In this connection, a convenient internal reference standard with which to gauge the amplitude of the fluorescence signal is realized in the form of the concurrent water Raman emission. Remote measurements of oil fluorescence emission spectra suggest that airborne laser fluorosensors are capable of detecting and characterizing the oil in a given slick and that environmental aging of these slicks does not significantly alter their fluorescence emission signature.

  15. Multi-trophic invasion resistance in Hawaii: bioacoustics, field surveys, and airborne remote sensing.

    PubMed

    Boelman, Natalie T; Asner, Gregory P; Hart, Patrick J; Martin, Roberta E

    2007-12-01

    We used airborne imaging spectroscopy and scanning light detection and ranging (LiDAR), along with bioacoustic recordings, to determine how a plant species invasion affects avian abundance and community composition across a range of Hawaiian submontane ecosystems. Total avian abundance and the ratio of native to exotic avifauna were highest in habitats with the highest canopy cover and height. Comparing biophysically equivalent sites, stands dominated by native Metrosideros polymorpha trees hosted larger native avian communities than did mixed stands of Metrosideros and the invasive tree Morella faya. A multi-trophic analysis strongly suggests that native avifauna provide biotic resistance against the invasion of Morella trees and exotic birds, thus slowing invasion "meltdowns" that disrupt the functioning of native Hawaiian ecosystems. PMID:18213957

  16. Airborne radioactivity survey of parts of Baggs SW and Baggs SE quadrangles, Carbon and Sweetwater counties, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 151 square miles of Baggs SW and Baggs SE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater counties by the U.S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a C-47 aircraft and consisted of parallel east-west flight lines spaced at quarter mile intervals, flown approximately 500 feet above the ground. Aerial photographs were used for pilot guidance, and the flight path of the aircraft was recorded by a gyrostabilized, continuous-strip-film camera. The distance of the aircraft from the ground was measured with a continuously recording radio altimeter. The width of the zone on the ground form which the anomalous radiation is measured at the nominal 500 foot flight altitude varied with the areal extent and the intensity of radioactivity of the source. For strong sources of radioactivity the width of the zone may be as much as 1,400 feet. Thus, quarter mile spacing of the flight lines would be adequate to detect anomalies from strong sources of radioactivity; however, small areas of considerable radioactivity midway between flight lines may not be noted. The approximate locations of twelve radioactivity anomalies are shown on the accompanying map. The plotted position of the anomalies may be in error by as much as a quarter mile owing to the errors in available base maps or to the existence of areas on the base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or to a combination of these elements. The radioactivity

  17. Airborne radioactivity survey of parts of Sand Creek SW and Sand Creek SE quadrangles, Sweetwater county, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 125 square miles of Sand Creek SW and Sand Creek SE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater counties by the U.S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a C-47 aircraft and consisted of parallel east-west flight lines spaced at quarter mile intervals, flown approximately 500 feet above the ground. Aerial photographs were used for pilot guidance, and the flight path of the aircraft was recorded by a gyrostabilized, continuous-strip-film camera. The distance of the aircraft from the ground was measured with a continuously recording radio altimeter. The width of the zone on the ground form which the anomalous radiation is measured at the nominal 500 foot flight altitude varied with the areal extent and the intensity of radioactivity of the source. For strong sources of radioactivity the width of the zone may be as much as 1,400 feet. Thus, quarter mile spacing of the flight lines would be adequate to detect anomalies from strong sources of radioactivity; however, small areas of considerable radioactivity midway between flight lines may not be noted. The approximate locations of nine radioactivity anomalies are shown on the accompanying map. The plotted position of the anomalies may be in error by as much as a quarter mile owing to the errors in available base maps or to the existence of areas on the base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or to a combination of these elements. The

  18. A survey of natural aggregate properties and characteristics important in remote sensing and airborne geophysics

    USGS Publications Warehouse

    Knepper, D.H.; Langer, W.H.; Miller, S.

    1995-01-01

    Natural aggregate is vital to the construction industry. Although natural aggregate is a high volume/low value commodity that is abundant, new sources are becoming increasingly difficult to find and develop because of rigid industry specifications, political considerations, development and transportation costs, and environmental concerns. There are two primary sources of natural aggregate: (1) exposed or near-surface bedrock that can be crushed, and (2) deposits of sand and gravel. Remote sensing and airborne geophysics detect surface and near-surface phenomena, and may be useful for detecting and mapping potential aggregate sources; however, before a methodology for applying these techniques can be developed, it is necessary to understand the type, distribution, physical properties, and characteristics of natural aggregate deposits. The distribution of potential aggregate sources is closely tied to local geologic history. Conventional exploration for natural aggregate deposits has been largely a ground-based operation, although aerial photographs and topographic maps have been extensively used to target possible deposits. Today, the exploration process also considers factors such as the availability of the land, space and water supply for processing, political and environmental factors, and distance from the market; exploration and planning cannot be separated. There are many physical properties and characteristics by which to judge aggregate material for specific applications; most of these properties and characteristics pertain only to individual aggregate particles. The application of remote sensing and airborne geophysical measurements to detecting and mapping potential aggregate sources, however, is based on intrinsic bulk physical properties and extrinsic characteristics of the deposits that can be directly measured, mathematically derived from measurement, or interpreted with remote sensing and geophysical data. ?? 1995 Oxford UniversityPress.

  19. Interactive interpretation of airborne gravity, magnetic, and drill-hole data within the crustal framework of the northern Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Haby S.; Senosy, Mahmoud. M.; Abdel Zaher, Mohamed

    2016-11-01

    The northern part of Western Desert represents the second most important oil-producing and gas provinces in Egypt. The aim of the present study is to highlight the subsurface structures, tectonic framework, and variation of the crust and upper mantle of the northern Western Desert. Geophysical data in the form of airborne gravity and magnetic maps as well as drill-hole data were used to achieve the objectives of the study. 2D interactive sequential modeling of aerogravity and aeromagnetic data was done along some selected profiles with constraints of the existing deep drill-holes at the study area. From these models, three maps for the depths to Precambrian basement, Conrad, and Moho surfaces were constructed. The results of this study indicate that the depth to the basement surface (thickness of the sedimentary section) ranges between 900 m at the southern parts and more than 5500 m at the northern parts. Meanwhile, the depth of Conrad discontinuity which reflect thickness of the upper crust; varies approximately between 10,000 m at the central and northern parts and 17,000 m at the southern parts of the area. While the Moho depth which represents the crustal thickness ranges from 27,000 m at the northern parts to 39,000 m southward. Integrating the results shows that the main compressive stress which influenced the studied area is in N55°W direction that supposed to cause primary shear in N25°W and N85°W directions with right and left lateral movements, respectively.

  20. The ancient harbour system of Terracina (Latium, Italy) obtained by gravity and seismic surveys.

    NASA Astrophysics Data System (ADS)

    di Nezza, Maria; di Filippo, Michele

    2010-05-01

    Historical research has shown that Terracina (Latina, Latium) played a fundamental role in the maritime and land traffic since before the foundation of the colony. The settlement was established where the organized system of maritime, land, coastal, and fluvial transport had the most ideal conditions to constitute an important commercial crossroads, apparently since the beginning of recorded history. In order to reconstruction the buried archaeological structures attributed to the ancient Roman port, traditionally attributed to Traiano, in the current area of the harbour of Terracina, it was carried out a gravity survey, more than 380 gravity stations. The gravity method enables to recognize the cavity and the structures of the buildings underground through the results of variations density in the subsoil. Seismic tomography treats the problem of identifying a buried structure as a wave propagation process by inverting the linearized wave equation to compute the spatial distribution of the slowness of the velocity. The purpose of our tomographic study is to further test the method and to guide archaeologists in their future excavations by locating and identifying buried structures. In the residual gravity anomaly map a series of positive anomalies are visible which confirm the round structures and the pier of the buried foundations of the Imperial harbour. Unfortunately, little remains of the functioning facilities of the harbour's activities. The modern construction of the harbour, in fact, has to be developed around the new inhabitable commercial area, know today as Terracina Bassa or Borgo alla Marina. It had to be developed with a modern infrastructure of a harbor area, as in the construction of the rooms for storage of goods, warehouses, as well as for the thermal baths, hotels and amphitheatre. Furthermore, there are always the positive anomalies that characterize the area to the north-east of "Montone" hill where archaeological remains are easily visible

  1. Insights into the Structure and Surface Geology of Isla Socorro, Mexico, from Airborne Magnetic and Gamma-Ray Surveys

    NASA Astrophysics Data System (ADS)

    Paoletti, V.; Gruber, S.; Varley, N.; D'Antonio, M.; Supper, R.; Motschka, K.

    2016-05-01

    The island of Socorro is located in the eastern Pacific Ocean, 650 km off the coast of Mexico. It is a rare example of an oceanic volcanic island whose above sea level volume is made up mostly of peralkaline trachytes and rhyolites, with subordinate mafic rocks. Subaerial volcanism started several hundred thousand years ago and continues until recent times. We present an investigation of surface and subsurface geology of the island, based on the first detailed extensive geophysical survey on the island. Acquired airborne magnetic and gamma-ray data were compared to existing geological information and supplemented with field investigations and satellite imagery. Magnetic data show a wide minimum in the central part of the island, possibly connected to a high-temperature zone in the deeper central portion of the volcano, likely to be due to a still hot magma body. The data also depict two parallel edges possibly suggesting the existence of a nested caldera. Analysis on upward continued magnetic data by recent imaging techniques highlighted two deep sources located around 5 km b.s.l., interpreted as feeding structures that are now filled with crystalline rocks. Gamma-ray data have been interpreted through integration with the geological survey results. Several previously known volcanic deposits have been identified based on radioelement distribution, and others have been redefined based on field evidence. A new succession of volcanic members is proposed, to be verified through more detailed geological mapping, geochemical analyses of rock samples and radiometric dating.

  2. Non-Destructive Survey of Archaeological Sites Using Airborne Laser Scanning and Geophysical Applications

    NASA Astrophysics Data System (ADS)

    Poloprutský, Z.; Cejpová, M.; Němcová, J.

    2016-06-01

    This paper deals with the non-destructive documentation of the "Radkov" (Svitavy district, Czech Republic) archaeological site. ALS, GPR and land survey mapping will be used for the analysis. The fortified hilltop settlement "Radkov" is an immovable historical monument with preserved relics of anthropogenic origin in relief. Terrain reconnaissance can identify several accentuated objects on site. ALS enables identification of poorly recognizable archaeological objects and their contexture in the field. Geophysical survey enables defunct objects identification. These objects are hidden below the current ground surface and their layout is crucial. Land survey mapping provides technical support for ALS and GPR survey. It enables data georeferencing in geodetic reference systems. GIS can then be used for data analysis. M. Cejpová and J. Němcová have studied this site over a long period of time. In 2012 Radkov was surveyed using ALS in the project "The Research of Ancient Road in Southwest Moravia and East Bohemia". Since 2015 the authors have been examining this site. This paper summarises the existing results of the work of these authors. The digital elevation model in the form of a grid (GDEM) with a resolution 1 m of 2012 was the basis for this work. In 2015 the survey net, terrain reconnaissance and GPR survey of two archaeological objects were done at the site. GDEM was compared with these datasets. All datasets were processed individually and its results were compared in ArcGIS. This work was supported by the Grant Agency of the CTU in Prague, grant No. SGS16/063/OHK1/1T/11.

  3. Arctic gravity exploration: state of the art and prospects

    NASA Astrophysics Data System (ADS)

    Koneshov, V. N.; Nepoklonov, V. B.; Pogorelov, V. V.; Solov'ev, V. N.; Afanas'eva, L. V.

    2016-05-01

    The application of the airborne gravimetry method for gravity measurements in the Arctic is considered. This method has been extensively employed in foreign studies for determining the figure of the Earth in high-latitude conditions. The possibility of conducting comparative studies along the extensive survey lines and the necessity of aerogravimetry studies for improving the global Earth's gravity field (EGF) models are discussed. The possibility of the efficient application of the modern EGF models for estimating the systematical errors for different types of gravimetry surveys and exploring the influence of the anomalous far-zone field in the calculations of the plumb line deviations is demonstrated.

  4. A survey of airborne radar systems for deployment on a High Altitude Powered Platform (HAPP)

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Leung, K. C.

    1979-01-01

    A survey was conducted to find out the system characteristics of commercially available and unclassified military radars suitable for deployment on a stationary platform. A total of ten domestic and eight foreign manufacturers of the radar systems were identified. Questionnaires were sent to manufacturers requesting information concerning the system characteristics: frequency, power used, weight, volume, power radiated, antenna pattern, resolution, display capabilities, pulse repetition frequency, and sensitivity. A literature search was also made to gather the system characteristics information. Results of the survey are documented and comparisons are made among available radar systems.

  5. Semi-automated structural analysis of high resolution magnetic and gamma-ray spectrometry airborne surveys

    NASA Astrophysics Data System (ADS)

    Debeglia, N.; Martelet, G.; Perrin, J.; Truffert, C.; Ledru, P.; Tourlière, B.

    2005-08-01

    A user-controlled procedure was implemented for the structural analysis of geophysical maps. Local edge segments are first extracted using a suitable edge detector function, then linked into straight discontinuities and, finally, organised in complex boundary lines best delineating geophysical features. Final boundary lines may be attributed by a geologist to lithological contacts and/or structural geological features. Tests of some edge detectors, (i) horizontal gradient magnitude (HGM), (ii) various orders of the analytic signal ( An), reduced to the pole or not, (iii) enhanced horizontal derivative (EHD), (iv) composite analytic signal (CAS), were performed on synthetic magnetic data (with and without noise). As a result of these comparisons, the horizontal gradient appears to remain the best operator for the analysis of magnetic data. Computation of gradients in the frequency domain, including filtering and upward continuation of noisy data, is well-suited to the extraction of magnetic gradients associated to deep sources, while space-domain smoothing and differentiation techniques is generally preferable in the case of shallow magnetic sources, or for gamma-ray spectrometry analysis. Algorithms for edge extraction, segment linking, and line following can be controlled by choosing adequate edge detector and processing parameters which allows adaptation to a desired scale of interpretation. Tests on synthetic and real case data demonstrate the adaptability of the procedure and its ability to produce basic layer for multi-data analysis. The method was applied to the interpretation of high-resolution airborne magnetic and gamma-ray spectrometry data collected in northern Namibia. It allowed the delineation of dyke networks concealed by superficial weathering and demonstrated the presence of lithological variations in alluvial flows. The output from the structural analysis procedure are compatible with standard GIS softwares and enable the geologist to (i) compare

  6. Evaluation of airborne geophysical surveys for large-scale mapping of contaminated mine pools: draft final report

    SciTech Connect

    Hammack, R. W.

    2006-12-28

    subtle mine pool anomalies. However, post-survey modeling suggested that thicker, more conductive mine pools might be detected at a more suitable location. The current study sought to identify the best time domain electromagnetic sensor for detecting mine pools and to test it in an area where the mine pools are thicker and more conductive that those in southwestern Virginia. After a careful comparison of all airborne time domain electromagnetic sensors (including both helicopter and fixed-wing systems), the SkyTEM system from Denmark was determined to be the best technology for this application. Whereas most airborne time domain electromagnetic systems were developed to find large, deep, highly conductive mineral deposits, the SkyTEM system is designed for groundwater exploration studies, an application similar to mine pool detection.

  7. Airborne Hydromapping - How high-resolution bathymetric surveys will change the research and work focused on waterbody-related topics

    NASA Astrophysics Data System (ADS)

    Steinbacher, Frank; Baran, Ramona; Dobler, Wolfgang; Aufleger, Markus

    2013-04-01

    Repetitive surveying of inshore waters and coastal zones is becoming more and more essential in order to evaluate water-level dynamics, structural and zonal variations of rivers and riparian areas, river degradation, water flow, reservoir sedimentation, delta growth, as well as coastal processes. This can only be achieved in an effective manner by employing hydrographic airborne laser scanning (hydromapping). A new laser scanner is introduced, which has been specifically designed for the acquisition of high-resolution hydrographic data in order to survey and monitor inland waters and shallow coastal zones. Recently, this scanner has been developed within the framework of an Austrian research cooperation between Riegl LMS and the Unit of Hydraulic Engineering at the University of Innsbruck. We present exemplary measurement results obtained with the compact airborne laser-scanning system during our project work. Along the Baltic Sea coast northeast of Kiel city, northern Germany, we obtained measurement depths up to 8 m under clear-water conditions. Moreover, we detect underwater dune-structures and the accumulation of sediment within groin structures. In contrast, under turbid water conditions we obtained depths of approximately 3 m along the Rhine River at Rheinfelden, German-Swiss border east of Basel city. Nevertheless, we were able to map small-scale and complex morphologic features within a fish ramp or bedrock cliffs. The laser data had been combined with sonar measurements displaying the bathymetry at depths of ca. 2-25 m in order to document comprehensively the actual hydrographic setting after the new construction of the hydropower plant Rheinfelden. In summary, a high-resolution spatial view on the ground of various waterbodies is now possible for the first time with point densities in the usual range of approximately 10-20 points/m². However, the combination of these data with high-resolution aerial (approximately < 5 cm/pixel) or spectral images offers

  8. Contribution of the airborne geophysical survey to the study of the regolith : A case study in southern Paris Basin.

    NASA Astrophysics Data System (ADS)

    Prognon, Francois; Lacquement, Fréderic; Deparis, Jacques; Martelet, Guillaume; Perrin, José

    2010-05-01

    Studies of soil and subsoil, also called regolith, are at the crossroads of scientific new challenging questions as well as new environmental needs. Historically, geological maps were focussed on solid geology. Present societal needs increasingly require knowledge of regolith properties: superficial studies combining geology, geochemistry and geophysics become essential to better understand the natural processes which govern the repartition and evolution of subsoil formations. Such progress is critical to better orient the use and management of natural and groundwater resources. Among other techniques, airborne geophysics is appropriate to provide information on near surface, because of i) its high spatial coverage ii) the rapidity of acquisition and iii) the variety of available sensors (magnetic, spectral radiometry, electromagnetic …). We illustrate the results of an airborne geophysical survey carried out in France, in "Région Centre" administrative region in the southern part of the Paris Basin. Spectral radiometry data were collected throughout "Région Centre" with a line spacing of 1 km. This method provides maps of potassium (K), uranium (U) and thorium (Th) which are the only naturally occurring elements with direct or indirect radioisotopes that produce gamma rays of sufficient intensity to be measured at airborne survey heights. Gamma-rays emitted from the Earth surface are related to the primary mineralogy and geochemistry of the bedrock and/or the nature of secondary weathering including regolith materials. Obtained images are confronted with former geological investigations (1:50 000e geological maps). Geophysical data and geological maps are generally consistent on most of the covered area since the first-rate information delivered by the spectrometry derives from the geochemistry of the solid geology. Second-rate gamma-ray responses come from superimposed allochtonous deposits as well as in situ geochemical modifications. For instance

  9. High-resolution gravity and seismic-refraction surveys of the Smoke Tree Wash area, Joshua Tree National Park, California

    USGS Publications Warehouse

    Langenheim, Victoria E.; Rymer, Michael J.; Catchings, Rufus D.; Goldman, Mark R.; Watt, Janet T.; Powell, Robert E.; Matti, Jonathan C.

    2016-03-02

    We describe high-resolution gravity and seismic refraction surveys acquired to determine the thickness of valley-fill deposits and to delineate geologic structures that might influence groundwater flow beneath the Smoke Tree Wash area in Joshua Tree National Park. These surveys identified a sedimentary basin that is fault-controlled. A profile across the Smoke Tree Wash fault zone reveals low gravity values and seismic velocities that coincide with a mapped strand of the Smoke Tree Wash fault. Modeling of the gravity data reveals a basin about 2–2.5 km long and 1 km wide that is roughly centered on this mapped strand, and bounded by inferred faults. According to the gravity model the deepest part of the basin is about 270 m, but this area coincides with low velocities that are not characteristic of typical basement complex rocks. Most likely, the density contrast assumed in the inversion is too high or the uncharacteristically low velocities represent highly fractured or weathered basement rocks, or both. A longer seismic profile extending onto basement outcrops would help differentiate which scenario is more accurate. The seismic velocities also determine the depth to water table along the profile to be about 40–60 m, consistent with water levels measured in water wells near the northern end of the profile.

  10. New Antarctic gravity anomaly grid for enhanced geodetic and geophysical studies in Antarctica

    NASA Astrophysics Data System (ADS)

    Scheinert, M.; Ferraccioli, F.; Schwabe, J.; Bell, R.; Studinger, M.; Damaske, D.; Jokat, W.; Aleshkova, N.; Jordan, T.; Leitchenkov, G.; Blankenship, D. D.; Damiani, T. M.; Young, D.; Cochran, J. R.; Richter, T. D.

    2016-01-01

    Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne, and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated leveling of the different gravity data sets with respect to an Earth gravity model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth gravity models to be derived and represent a major step forward toward solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica.

  11. The US Geological Survey's side-looking airborne radar acquisition program: Image data from the Rocky Mountains to the Pacific

    SciTech Connect

    Kovar, A.N.; Schoonmaker, J.W. Jr. )

    1993-04-01

    The US Geological Survey (USGS) has been systematically collecting side-looking airborne radar (SLAR) image data for the US since 1980. The image strip swaths, ranging in width from 20 to 46 km, are acquired commercially by X-band (3 cm) radar systems. Data are acquired with 60 percent side-lap for better mosaic preparation and stereoscopic capability. The image strips are assembled into 1[degree] x 2[degree] mosaic quadrangles that are based on the USGS 1:250,000-topographic map series for control, format, and nomenclature. These mosaics present the data in a broad synoptic view that facilitates geologic interpretation. SLAR image mosaics have been prepared for more than 35 percent of the US west of the Rocky Mountain front. In addition to quadrangle mosaics, regional composite mosaics have been prepared as value-added products. These include Pacific Northwest (14 quadrangles), southern California Coastal (from San Francisco to San Diego), Reno-Walker (includes parts of Yellowstone and Grand Teton National Parks), Uinta Basin (Salt Lake City, Price and Grand Junction), and Salton Sea Region (San Diego, Santa Ana, El Centro and Salton Sea). Most of the image data are available on computer compatible tapes and photographic products. To make the data more accessible and reasonably priced, the strip images are being processed into CD-ROM (compact disc, read-only memory). One demonstration CD-ROM includes the mosaics of Las Vegas, Mariposa, Ritzville, Walla Walla, and Pendleton quadrangles.

  12. Aeromagnetic, gravity anomaly, and derivative maps of the Craig and Dixon Entrance 1-degree by 3-degree quadrangles of southeastern Alaska

    USGS Publications Warehouse

    Wynn, Jeffrey C.; Kucks, R.P.; Grybeck, D.J.

    1999-01-01

    This CD-ROM contains aeromagnetic, gravity, geology, and topographic data as well as several derivative products, for the Craig and Dixon Entrance 1? ? 3? quadrangles of Southeastern Alaska. The data were collected by the U.S. Geological Survey directly and by means of several contract airborne surveys, through August 1991.

  13. OSSE impact analysis of airborne ocean surveys for improving upper-ocean dynamical and thermodynamical forecasts in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Halliwell, George R.; Kourafalou, Vassiliki; Le Hénaff, Matthieu; Shay, Lynn K.; Atlas, Robert

    2015-01-01

    A prototype, rigorously validated ocean Observing System Simulation Experiment (OSSE) system is used to evaluate the impact of different sampling strategies for rapid-response airborne ocean profile surveys in the eastern interior Gulf of Mexico. Impacts are assessed with respect to improving ocean analyses, and forecasts initialized from those analyses, for two applications: improving oil spill forecasts and improving the ocean model response to tropical cyclone (TC) forcing. Rapid model error growth in this region requires that repeat surveys be conducted frequently in time, with separation of less than 4 days required to approach maximum error reduction in model analyses. Substantial additional error reduction in model dynamical fields is achieved by deploying deep (1000 m) AXCTDs instead of shallow (400 m) AXBTs. Shallow AXBTs constrain the ocean thermal field over the upper 400 m nearly as well as deep AXCTDs. However, in addition to constraining ocean fields over a greater depth range, AXCTDs also measure salinity profiles and more accurately constrain upper-ocean density than AXBTs, leading to a more accurate representation of upper ocean pressure and velocity fields. Sampling AXCTD profiles over a one-half degree array compared to one degree leads to substantial additional error reduction by constraining variability with horizontal scales too small to be corrected by satellite altimetry assimilation. A 2-day lag in availability of airborne profiles does not increase errors in dynamical ocean fields, but it does increase errors in upper-ocean thermal field including Tropical Cyclone Heat Potential (TCHP), demonstrating that these profiles must be rapidly made available for assimilation to improve TC forecasts. The additional error reduction in ocean analyses achieved by assimilation of airborne surveys translates into significantly improved forecasts persisting over time intervals ranging between 1 and 2 weeks for most model variables but several weeks for

  14. Snow measurement system for airborne snow surveys (GPR system from helicopter) in high mountian areas.

    NASA Astrophysics Data System (ADS)

    Sorteberg, Hilleborg K.

    2010-05-01

    In the hydropower industry, it is important to have precise information about snow deposits at all times, to allow for effective planning and optimal use of the water. In Norway, it is common to measure snow density using a manual method, i.e. the depth and weight of the snow is measured. In recent years, radar measurements have been taken from snowmobiles; however, few energy supply companies use this method operatively - it has mostly been used in connection with research projects. Agder Energi is the first Norwegian power producer in using radar tecnology from helicopter in monitoring mountain snow levels. Measurement accuracy is crucial when obtaining input data for snow reservoir estimates. Radar screening by helicopter makes remote areas more easily accessible and provides larger quantities of data than traditional ground level measurement methods. In order to draw up a snow survey system, it is assumed as a basis that the snow distribution is influenced by vegetation, climate and topography. In order to take these factors into consideration, a snow survey system for fields in high mountain areas has been designed in which the data collection is carried out by following the lines of a grid system. The lines of this grid system is placed in order to effectively capture the distribution of elevation, x-coordinates, y-coordinates, aspect, slope and curvature in the field. Variation in climatic conditions are also captured better when using a grid, and dominant weather patterns will largely be captured in this measurement system.

  15. Test plan and preliminary report of airborne electromagentic environment survey over USA urban areas 0.4 to 18.0 GHz

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Hill, J. S.

    1975-01-01

    An airborne electromagnetic environment survey is described of five urban areas where terrestrially-generated radio-frequency interference was measured over the frequency range from 0.4 to 18.0 GHz. A chartered Cessna 402 aircraft contained necessary measurement test equipment, including the receiving antennas mounted beneath the fuselage. Urban areas including Washington, D.C.; Baltimore, MD; Philadelphia, PA; New York, NY; Chicago, ILL; and Palestine, TX were surveyed. A flight test plan and preliminary test results for the 0.4 to 1.4 GHz frequency range, are included; a final test report describes more detailed results.

  16. Sensitisation to airborne moulds and severity of asthma: cross sectional study from European Community respiratory health survey

    PubMed Central

    Zureik, Mahmoud; Neukirch, Catherine; Leynaert, Bénédicte; Liard, Renata; Bousquet, Jean; Neukirch, Françoise

    2002-01-01

    Objective To assess whether the severity of asthma is associated with sensitisation to airborne moulds rather than to other seasonal or perennial allergens. Design Multicentre epidemiological survey in 30 centres. Setting European Community respiratory health survey. Participants 1132 adults aged 20-44 years with current asthma and with skin prick test results. Main outcome measure Severity of asthma according to score based on forced expiratory volume in one second, number of asthma attacks, hospital admissions for breathing problems, and use of corticosteroids in past 12 months. Results The frequency of sensitisation to moulds (Alternaria alternata or Cladosporium herbarum, or both) increased significantly with increasing asthma severity (odds ratio 2.34 (95% confidence interval 1.56 to 3.52) for either for severe v mild asthma). This association existed in all of the study areas (gathered into regions), although there were differences in the frequency of sensitisation. There was no association between asthma severity and sensitisation to pollens or cats. Sensitisation to Dermatophagoides pteronyssinus was also positively associated with severity. In multivariable logistic regressions including sensitisation to moulds, pollens, D pteronyssinus, and cats simultaneously, the odds ratios for sensitisation to moulds were 1.48 (0.97 to 2.26) for moderate v mild asthma and 2.16 (1.37 to 3.35) for severe v mild asthma (P<0.001 for trend). Conclusions Sensitisation to moulds is a powerful risk factor for severe asthma in adults. This should be taken into account in primary prevention, management, and patients' education. What is already known on this topicSensitisation to moulds is a known risk factor for life threatening exacerbations of asthmaIt is unknown whether such sensitisation is generally associated with severity of asthmaWhat this study addsThe prevalence of sensitisation to moulds (Alternaria alternata or Cladosporium herbarum, or both) increased with

  17. Airborne Grid Sea-Ice Surveys for Comparison with Cryosat-2

    NASA Astrophysics Data System (ADS)

    Brozena, J. M.; Gardner, J. M.; Liang, R.; Hagen, R. A.; Ball, D.; Newman, T.

    2015-12-01

    The Naval Research Laboratory is studying of the changing Arctic with a focus on ice thickness and distribution variability. The goal is optimization of computer models used to predict sea ice changes. An important part of our study is to calibrate/validate Cryosat-2 ice thickness data prior to its incorporation into new ice forecast models. The footprint of the altimeter over sea-ice is a significant issue in any attempt to ground-truth the data. Along-track footprints are reduced to ~ 300 m by SAR processing of the returns. However, the cross-track footprint is determined by the topography of the surface. Further, the actual return is the sum of the returns from individual reflectors within the footprint making it difficult to interpret the return, and optimize the waveform tracker. We therefore collected a series of grids of scanning LiDAR and radar on sub-satellite tracks over sea-ice that would extend far enough cross-track to capture the illuminated area. The difficulty in the collection of such grids, which are comprised of adjacent overlapping tracks is ice motion of as much as 300 m over the duration of a single flight track (~ 20 km) of data collection. With a typical LiDAR swath width of < 500m adjustment of the survey tracks in near real-time for the ice motion is necessary for a coherent data set. This was accomplished by a an NRL devised photogrammetric method of ice velocity determination. Post-processing refinements resulted in typical track-to-track miss-ties of ~ 1-2 m, much of which could be attributed to ice deformation over the period of the survey. This allows us to reconstruct the ice configuration to the time of the satellite overflight, resulting in a good picture of the surface actually illuminated by the radar. The detailed 2-d LiDAR image is the snow surface, not the underlying ice presumably illuminated by the radar. Our hope is that the 1-D radar profiles collected along the LiDAR swath centerlines will be sufficient to correct the

  18. Regional gravity and magnetic surveys in the Albion Mountains area of southern Idaho

    USGS Publications Warehouse

    Mabey, Don R.; Wilson, Carol W.

    1973-01-01

    Fault-bounded basins containing several thousand feet of sedimentary and volcanic rock of Cenozoic age are indicated by gravity lows in the Oakley area and in Upper-Raft River and Raft River Valleys. A gravity low and a magnetic high in the north end of Raft River Valley extends over the Cotterel Mountains and into Marsh Creek valley. These anomalies may reflect a Tertiary caldera. A gravity high and a magnetic high in the Raft River Valley south of Malta suggests a buried intrusive that may be the source of heat for the thermal waters in that area.

  19. The Continuous wavelet in airborne gravimetry

    NASA Astrophysics Data System (ADS)

    Liang, X.; Liu, L.

    2013-12-01

    Airborne gravimetry is an efficient method to recover medium and high frequency band of earth gravity over any region, especially inaccessible areas, which can measure gravity data with high accuracy,high resolution and broad range in a rapidly and economical way, and It will play an important role for geoid and geophysical exploration. Filtering methods for reducing high-frequency errors is critical to the success of airborne gravimetry due to Aircraft acceleration determination based on GPS.Tradiontal filters used in airborne gravimetry are FIR,IIR filer and so on. This study recommends an improved continuous wavelet to process airborne gravity data. Here we focus on how to construct the continuous wavelet filters and show their working principle. Particularly the technical parameters (window width parameter and scale parameter) of the filters are tested. Then the raw airborne gravity data from the first Chinese airborne gravimetry campaign are filtered using FIR-low pass filter and continuous wavelet filters to remove the noise. The comparison to reference data is performed to determinate external accuracy, which shows that continuous wavelet filters applied to airborne gravity in this thesis have good performances. The advantages of the continuous wavelet filters over digital filters are also introduced. The effectiveness of the continuous wavelet filters for airborne gravimetry is demonstrated through real data computation.

  20. Gravity and geoid model for South America

    NASA Astrophysics Data System (ADS)

    Blitzkow, Denizar; Oliveira Cancoro de Matos, Ana Cristina; do Nascimento Guimarães, Gabriel; Pacino, María Cristina; Andrés Lauría, Eduardo; Nunes, Marcelo; Castro Junior, Carlos Alberto Correia e.; Flores, Fredy; Orihuela Guevara, Nuris; Alvarez, Ruber; Napoleon Hernandez, José

    2016-04-01

    In the last 20 years, South America Gravity Studies (SAGS) project has undertaken an ongoing effort in establishing the fundamental gravity network (FGN); terrestrial, river and airborne relative gravity densifications; absolute gravity surveys and geoid (quasi-geoid) model computation for South America. The old FGN is being replaced progressively by new absolute measurements in different countries. In recent years, Argentina, Bolivia, Brazil, Ecuador, Paraguay and Venezuela organizations participated with relative gravity surveys. Taking advantage of the large amount of data available, GEOID2015 model was developed for 15°N and 57°S latitude and 30 ° W and 95°W longitude based on EIGEN-6C4 until degree and order 200 as a reference field. The ocean area was completed with mean free air gravity anomalies derived from DTU10 model. The short wavelength component was estimated using FFT. The global gravity field models EIGEN-6C4, DIR_R5 were used for comparison with the new model. The new geoid model has been evaluated against 1,319 GPS/BM, in which 592 are located in Brazil and the reminder in other countries. The preliminary RMS difference between GPS/BM and GEOID2015 throughout South America and in Brazil is 46 cm and 17 cm, respectively. New activities are carrying out with the support of the IGC (Geographic and Cartographic Institute) under the coordination of EPUSP/LTG and CENEGEO (Centro de Estudos de Geodesia). The new project aims to establish new gravity points with the A-10 absolute gravimeter in South America. Recent such surveys occurred in São Paulo state, Argentina and Venezuela.

  1. Airborne LaCoste & Romberg gravimetry: a space domain approach

    NASA Astrophysics Data System (ADS)

    Abbasi, M.; Barriot, J. P.; Verdun, J.

    2007-04-01

    This paper introduces a new approach to reduce the airborne gravity data acquired by a LaCoste & Romberg (L&R) air/sea gravimeter, or other similar gravimeters. The acceleration exerted on the gravimeter is the sum of gravity and the vertical and Eötvös accelerations of the aircraft. The L&R gravimeter outputs are: (1) the beam position, (2) the spring tension and (3) the cross coupling. Vertical and Eötvös accelerations are computed from GPS-derived aircraft positions. However, the vertical perturbing acceleration sensed by the gravimeter is not the same as the one sensed by the aircraft (via GPS). A determination of the aircraft-to-sensor transfer function is necessary. The second-order differential equation of the motion of the gravimeter’s beam mixes all the input and output parameters of the gravimeter. Conventionally, low-pass filtering in the frequency domain is used to extract the gravity signal, the filter being applied to each flight-line individually. By transforming the differential equation into an integral equation and by introducing related covariance matrices, we develop a new filtering method based on a least-squares approach that is able to take into account, in one stage, the data corresponding to all flight-lines. The a posteriori covariance matrix of the estimated gravity signal is an internal criterion of the precision of the method. As an example, we estimate the gravity values along the flight-lines from an airborne gravity survey over the Alps and introduce an a priori covariance matrix of the gravity disturbances from a global geopotential model. This matrix is used to regularize the ill-posed Fredholm integral equation introduced in this paper.

  2. Airborne data acquisition techniques

    SciTech Connect

    Arro, A.A.

    1980-01-01

    The introduction of standards on acceptable procedures for assessing building heat loss has created a dilemma for the contractor performing airborne thermographic surveys. These standards impose specifications on instrumentation, data acquisition, recording, interpretation, and presentation. Under the standard, the contractor has both the obligation of compliance and the requirement of offering his services at a reasonable price. This paper discusses the various aspects of data acquisition for airborne thermographic surveys and various techniques to reduce the costs of this operation. These techniques include the calculation of flight parameters for economical data acquisition, the selection and use of maps for mission planning, and the use of meteorological forecasts for flight scheduling and the actual execution of the mission. The proper consideration of these factors will result in a cost effective data acquisition and will place the contractor in a very competitive position in offering airborne thermographic survey services.

  3. Detailed gravity and aeromagnetic surveys of the Cove Fort-Sulphurdale KGRA and vicinity, Millard and Beaver Counties, Utah. Topical report

    SciTech Connect

    Cook, K.L.; Serpa, L.F.; Pe, W.

    1980-01-01

    A detailed gravity survey (comprising 231 stations over about 900 km/sup 2/) was made in the Cove Fort-Sulphurdale Known Geothermal Resource area (KGRA) and vicinity, Millard and Beaver counties, Utah to assist in the appraisal of the potential of this area as a geothermal resource. The survey reinforced the results and information obtained in the previous regional gravity surveys comprising 522 stations. The gravity data from about 700 stations were reduced and compiled as a terrain-corrected (out to 20 km) Bouguer gravity anomaly map with 1-mgal contour interval. In August 1975, an aeromagnetic survey was flown over part of the survey area at a constant barometric elevation of 12,000 ft (3660 m). These aeromagnetic data are used to supplement the interpretation of the gravity data. The aeromagnetic field intensity residual anomaly map and the second-order polynomial residual aeromagnetic map (obtained by removing a second-order polynomial surface) are presented with a 20-gamma contour interval. Two north-south profiles and one east-west profile were selected for magnetic interpretative modeling. The two north-south profiles were also stacked and averaged over 6-km-wide strips and modeled. The occurrences of hydrothermal alteration, hot spring deposits, and flowing hot springs coincide with inferred fault zones. No evidence of extensive alteration can be interpreted from the magnetic data.

  4. Gravity and Magnetic Survey of Southern Oklahoma Alcugen in Texas Panhandle, Near the 2000 earthquake swarm North of Amarillo

    NASA Astrophysics Data System (ADS)

    Manns, S.; Gurrola, H.; Robinson, R.; Horton, M.; Herrmann, M.; Seshhadri, S.; Anderson, H.; Bribiesca, E.; Lindsey, C.; Montalvo, R.; Cyrek, C.; Allen, T.; Hoemberg, J.; Hassan, A.

    2005-12-01

    The Texas panhandle is not a region normally thought of as being prone to seismic activity. Earthquakes with magnitudes of 3 to 4 do however occur in this region every year or so and are felt by residents in the area. There are historical reports of earthquakes of magnitude 5 during the early twentieth century. The earthquakes in this region are most likely associated with displacement on old faults related to the Southern Oklahoma Aulacogen (SOA, 600 Ma) which was deformed during the Ouachita orogeny to form the Wichita Mts. During the summer of 2000 there were an unusually large number of earthquakes for this region, five, all from the same location a few kilometers north of Amarillo Texas, 35.39 degrees north latitude and 101.81 degrees west longitude according to the NEIC catalogue. The non-seismic exploration class at Texas Tech University collected and interpreted gravity and magnetic data along a dirt road crossing the location of this earthquake "swarm" (yes in Texas 5 is a swarm) to determine if the old faults of the SOA coincide with the location of these earthquakes. The survey was conducted along a service road of the Santa Fe Railroad that crosses US 87 approximately 20 miles north of Amarillo, Texas trending in a south-southwest direction. Gravity data were collected every 100m along a 5 km profile using Warden and Lacoste gravity meters with elevation control provided by leveling survey tied to elevation markers on the map. Gravity data were colleted, using GPS elevation location and elevation, on roads over more than 20 km surrounding the local survey to provide regional control. Magnetic data were collected along the 5 km profile. Models derived from these data indicate a 200 m thick layer of poorly consolidated sediments with densities of 2.0 g/cc that can be interpreted as the Ogallala aquifer overlaying a layer with density of 2.6 g/cc. The interface between these layers is very structured and has at least three sharp ridges that we interpret as

  5. 3D modelling of an aero-gravity and -magnetic survey as an first exploration step in a frontier basin

    NASA Astrophysics Data System (ADS)

    Köther, Nils; Eckard, Marcel; Götze, Hans-Jürgen

    2010-05-01

    The West African Taoudeni basin covers a desert area of about 1.8 million km² and is one of the last frontier basins worldwide. Here Wintershall Holding AG holds acreage of about 68000 km². During 2005-2007 geological surveys and an aero-gravity and -magnetic survey were conducted in this area. The potential field modelling should contribute first insight about the subsurface to plan an economic seismic survey. 2D models lead to poor results. 2008 the results of an internship (NK) were 3D subsurface models, which were enhanced during the following diploma thesis (Köther, 2009). Complex igneous rocks and sparsely distributed constraints lead to an ambiguous interpretation. Therefore, several simple 3D models were compiled with the in-house software IGMAS+, which base on geological ideas of the underground and fit well the measured data. These basic models allow a geophysical evaluation of different geological theories about the subsurface. Also, for a thorough interpretation field transformations (Euler, Curvature, and Derivatives) were calculated. These results led to new constraints for further interpretation of the basin structures and therefore they are important contributions for future exploration e.g. the planning of seismic surveys.

  6. Precise gravity-field modeling in the area of the Japanese Antarctic station Syowa and evaluation of recent EGMs

    NASA Astrophysics Data System (ADS)

    Fukuda, Yoichi; Nogi, Yoshifumi; Matsuzaki, Kazuya

    2016-03-01

    By combining a Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) Earth Gravity Model (EGM) and in situ gravity data obtained from the Japanese Antarctic Research Expedition (JARE) surveys, we estimated the regional gravity field in the area of Syowa Station, a Japanese research station located in Lützow-Holm Bay, East Antarctica. In situ data sets that were used consisted of land gravity data collected since 1967, shipborne data collected since 1985 and airborne gravity data collected in 2006. The GOCE direct (DIR) solution release 5 (R5) model was used as the long-wavelength reference of the gravity field. Using these data sets, we calculated gravity anomalies and geoid heights at 1-by-1‧ grid by means of least-squares collocation. The resulting geoid height at Syowa Station was compared with a local height based on GPS, spirit leveling and tide gauge data. The result suggests that the sea surface height at Syowa Station is -1.57 m, which is consistent with a dynamic ocean topography model. During this investigation, we also evaluated GOCE EGMs and other recent EGMs by comparing them with the airborne gravity data. The results indicate that the GOCE DIR R5 produced the smallest RMS (Root Mean Square) differences and that the newer models performed nearly as well. These comparisons demonstrate the importance of using reliable in situ data when evaluating satellite-only EGMs.

  7. Hydrogeologic inferences from drillers' logs and from gravity and resistivity surveys in the Amargosa Desert, southern Nevada

    USGS Publications Warehouse

    Oatfield, W.J.; Czarnecki, J.B.

    1991-01-01

    The Amargosa Desert of southern Nevada, in the Basin and Range province, is hydraulically downgradient from Yucca Mountain, the potential site of a repository for high-level nuclear waste. Groundwater flow paths and flow rates beneath the Amargosa Desert are controlled in part by the total saturated thickness and the hydraulic properties of basin-fill alluvial sediments. Drillers' logs of water wells completed in alluvium were analyzed to help characterize the hydrogeologic framework underlying the Amargosa Desert. Fractions of coarse-grained sediments, calculated from each of these logs, were contoured using a universal-kriging routine to interpolate values. Results from a previous electrical sounding survey also were contoured, including the estimated depth to Paleozoic (?) basement rocks. The vertical electric sounding results were obtained from individual depth-to-resistivity profiles, from which the average resistivity of the total profile and the resistivity of the upper 75 m were calculated. The distribution and variations in average resistivity of the total depth correlated reasonably well with the distribution of variations in regional gravity. Patterns of contours of the resistivity of the upper 75 m of alluvium were similar to patterns of regional contours of the predominant cation (sodium) in ground water. Gravity lows correspond in some places to the presence of lacustrine, eolian, or marsh surface deposits, which may function as barriers to groundwater flow. Gravity lows also correspond to areas with thick basin-fill sediments, which was corroborated by depth-to-basement data determined from vertical electric soundings. Depths to Paleozoic (?) basement rocks may be as much as 1600 m based on data from the resistivity survey, which were corroborated in part by seismic-refraction survey data. Small variations exist in the percentage of the basin fill that is saturated. The unsaturated zone is always < 15% of the alluvial column. Analysis of depth

  8. Gravity survey and depth to bedrock in Carson Valley, Nevada-California

    USGS Publications Warehouse

    Maurer, D.K.

    1985-01-01

    Gravity data were obtained from 460 stations in Carson Valley, Nevada and California. The data have been interpreted to obtain a map of approximate depth to bedrock for use in a ground-water model of the valley. This map delineates the shape of the alluvium-filled basin and shows that the maximum depth to bedrock exceeds 5,000 feet, on the west side of the valley. A north-south trending offset in the bedrock surface shows that the Carson-Valley/Pine-Nut-Mountain block has not been tilted to the west as a simple unit, but is comprised of several smaller blocks. (USGS)

  9. The use of high resolution ground and airborne magnetic surveys to evaluate the geometry of hydrothermal alteration zones over volcanic provinces (Invited)

    NASA Astrophysics Data System (ADS)

    Bouligand, C.; Glen, J. M.

    2013-12-01

    Geophysical methods can provide critical constraints on the distribution and volume of hydrothermal alteration, important parameters in understanding the evolution of geothermal systems. Because hydrothermal alteration modifies the magnetic properties of the volcanic substratum, magnetic surveys can be used to provide constraints on the distribution of hydrothermal alteration at depth. Using Yellowstone caldera as an example, we show that both ground and airborne magnetic surveys can be used to map and assess the volume of hydrothermal alteration. Ground magnetic surveys over unaltered volcanic terranes display high-amplitude, short-wavelength anomalies, in contrast to smooth, subdued magnetic anomalies over volcanic substrata demagnetized by hydrothermal alteration. We use this contrast to map areas of hydrothermal alteration in detail. Inverse methods applied to high-resolution airborne and ground magnetic data can be used to create three-dimensional models of the distribution of magnetization and thus illuminate the geometry of hydrothermal alteration. Because of the non-uniqueness of potential fields, the construction of inverse models requires simplifying assumptions on the distribution of magnetization, knowledge of induced and remanent magnetization of fresh and altered geological units, and detailed geological and geophysical data. Within the three hydrothermal sites that we investigated in Yellowstone National Park, subdued short-wavelength signal indicates pervasive demagnetization (alteration) of the shallow substratum that extends over larger areas than initially mapped by geology. These data also reveal that the largest degree of demagnetization (alteration) and maximum thicknesses of demagnetized (altered) substratum, reaching a few hundred meters, are associated with hydrothermal vents and with superficial hydrothermal alteration. Our three dimensional models of magnetization provide estimates of the volume of buried hydrothermal alteration ranging

  10. 3D Geothermal Modelling Using Gravity Survey on Dolok Marawa, Simalungun District, North Sumatera

    NASA Astrophysics Data System (ADS)

    Rivandi, A.; Destawan, R.; Fajri, Z. R.; Hidayat, W.

    2016-01-01

    In North Sumatera, gravity method is applied to identify the geothermal model. This method measured the earth gravitational field. This research has 160 measurement points covering 9 square kilometers. We obtained complete Bouguer anomaly values ranging 85 mGal - 130.68 mGal interpreted as a heat source of andesitic igneous rocks that are affected by the presence of Mount Bahtopu magma chamber. We interpreted the values between 40 mGal - 80 mGal as reservoir and caprock. The 3D gravity inverse modelling conducted using Gravblox, and identifying the following lithologies; Toba Pyroclastic Fall (Qjt) with density 1.92 g/cm3, Toba Pyroclastic Flow (Qjt) with density 2.00 g/cm3, Mount Bahtopu Andesite (Qlb) with density 2.4 g/cm3, and 2.6 g/cm3 which is interpreted as heat source in form of andesitic rock and Mount Bahtopu magma chamber. This heat source is estimated to be at a depth of 1.45 km to 3.78 km below the surface.

  11. Aeromagnetic and Gravity Surveys in Afghanistan: A Web Site for Distribution of Data

    USGS Publications Warehouse

    Sweeney, Ronald E.; Kucks, Robert P.; Hill, Patricia L.; Finn, Carol A.

    2006-01-01

    Aeromagnetic data were digitized from aeromagnetic maps created from aeromagnetic surveys flown in southeastern and southern Afghanistan in 1966 by PRAKLA, Gesellschaft fur praktische Lagerstattenforschung GmbH, Hannover, Germany, on behalf of the 'Bundesanstalt fur Bodenforschung', Hannover, Germany. The digitization was done along contour lines, followed by interpolation of the data along the original survey flight-lines. Survey and map specifications can be found in two project reports, 'prakla_report_1967.pdf' and 'bgr_report_1968.pdf', made available in this open-file report.

  12. Airborne gamma-ray spectrometer and magnetometer survey: Forsyth quadrangle, Round Up quadrangle, Hardin quadrangle (Montana), Sheridan quadrangle, (Wyoming). Final report

    SciTech Connect

    Not Available

    1981-01-01

    An airborne combined radiometric and magnetic survey was performed for the Department of Energy (DOE) over the area covered by the Forsyth, Hardin, and Sheridan, and Roundup, 1:250,000 National Topographic Map Series (NTMS), quadrangle maps. The survey was part of DOE's National Uranium Resource Evaluation (NURE) program. Data were collected by a helicopter equipped with a gamma-ray spectrometer with a large crystal volume, and with a high sensitivity proton precession magnetometer. The radiometric system was calibrated at the Walker Field Calibration Pads and the Lake Mead Dynamic Test Range. Data quality was ensured during the survey by daily test flights and equipment checks. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, plotted, and contoured to produce anomaly maps based on the radiometric response of individual geological units. The anomalies were interpreted and an interpretation map produced. Volume I contains a description of the systems used in the survey, a discussion of the calibration of the systems, the data collection procedures, the data processing procedures, the data presentation, the interpretation rationale, and the interpretation methodology. A separate Volume II for each quadrangle contains the data displays and the interpretation results.

  13. Airborne gravimetry for geoid, geopotential models and GOCE - Himalaya and Antarctica cases (Invited)

    NASA Astrophysics Data System (ADS)

    Forsberg, R.; Olesen, A. V.

    2013-12-01

    DTU-Space has since many years carried out large area airborne surveys over both polar, tropical and temperate regions, especially for geoid determination and global geopotential models. Recently we have started flying two gravimeters (LCR and Chekan-AM) side by side for increased reliability and redundancy. Typical gravity results are at the 2 mGal rms level, translating into 5-10 cm accuracy in geoid. However, in rough mountainous areas results can be more noisy, mainly due to long-period mountain waves and turbulence. In the paper we outline results of recent challenging campaigns in Nepal (2010) and Antarctica (Antarctic Peninsula and East Antarctica, 2010-13). The latest Antarctic campaign 2012/13, carried out in cooperation with the British Antarctic Survey, Norwegian Polar Institute, and the Argentine Antarctic Institute, involved air drops of fuel to a remote field camp in the Recovery Lakes region, one of the least explored region of deep interior Antarctica. The airborne data collected are validated by cross-over comparisons and comparisons to independent data (IceBridge), and serve at the same time as an independent validation of GOCE satellite gravity data, confirming the satellite data to contain information at half-wavelengths down to 80 km. With no bias between the airborne data and GOCE, airborne gravimetry is perfectly suited to cover the GOCE data gap south of 83 S. We recommend an international, coordinated airborne gravity effort should be carried out over the south polar gap as soon as possible, to ensure a uniform global accuracy of GOCE heritage future geopotential models.

  14. Airborne fungi--a resurvey

    SciTech Connect

    Meyer, G.H.; Prince, H.E.; Raymer, W.J.

    1983-07-01

    A 15-month survey of airborne fungi at 14 geographical stations was conducted to determine the incidence of different fungal genera. Five of these stations were surveyed 25 years earlier. A comparison between previous studies and present surveys revealed similar organisms at each station with slight shifts in frequency of dominant genera.

  15. Making Carbon Emissions Remotely Sensible: Flux Observations of Carbon from an Airborne Laboratory (FOCAL), its Near-Surface Survey of Carbon Gases and Isotopologues on Alaska's North Slope

    NASA Astrophysics Data System (ADS)

    Dobosy, R.; Dumas, E. J.; Sayres, D. S.; Healy, C. E.; Munster, J. B.; Baker, B.; Anderson, J. G.

    2014-12-01

    Detailed process-oriented study of the mechanisms of conversion in the Arctic of fossil carbon to atmospheric gas is progressing, but necessarily limited to a few point locations and requiring detailed subsurface measurements inaccessible to remote sensing. Airborne measurements of concentration, transport and flux of these carbon gases at sufficiently low altitude to reflect surface variations can tie such local measurements to remotely observable features of the landscape. Carbon dioxide and water vapor have been observable for over 20 years from low-altitude small aircraft in the Arctic and elsewhere. Methane has been more difficult, requiring large powerful aircraft or limited flask samples. Recent developments in spectroscopy, however, have reduced the power and weight required to measure methane at rates suitable for eddy-covariance flux estimates. The Flux Observations of Carbon from an Airborne Laboratory (FOCAL) takes advantage of Integrated Cavity-Output Spectroscopy (ICOS) to measure CH4, CO2, and water vapor in a new airborne system. The system, moreover, measures these gases' stable isotopologues every two seconds or faster helping to separate thermogenic from biogenic emissions. Paired with the Best Airborne Turbulence (BAT) probe developed for small aircraft by NOAA's Air Resources Laboratory and a light twin-engine aircraft adapted by Aurora Flight Sciences Inc., the FOCAL measures at 6 m spacing, covering 100 km in less than 30 minutes. It flies between 10 m and 50 m above ground interspersed with profiles to the top of the boundary layer and beyond. This presentation gives an overview of the magnitude and variation in fluxes and concentrations of CH4, CO2, and H2O with space, time, and time of day in a spatially extensive survey, more than 7500 km total in 15 flights over roughly a 100 km square during the month of August 2013. An extensive data set such as this at low altitude with high-rate sampling addresses features that repeat on 1 km scale

  16. Interpretation of an airborne geophysical survey in southern Paris Basin: towards a lithological cartography, key tool for the management of shrinking/swelling clay problems

    NASA Astrophysics Data System (ADS)

    Prognon, F.; Tourliere, B.; Perrin, J.; Lacquement, F.; Martelet, G.; Deparis, J.; Gourdier, S.; Drufin, S.

    2011-12-01

    Regolith formations support a full spectrum of human activities. Among others, they provide a source of extractable materials and form the substratum of soils. As such, they should be considered as a capital to be managed and protected. Moreover, one of the main challenges for present and future land settlement is to prevent house building programs from being planned inside shrink-swell risky areas which is only possible thanks to an complete lithological mapping of the french regolith. We illustrate here the results of the geological interpretation of an airborne geophysical survey carried out in "Région Centre" administrative region in the southern part of the Paris Basin, in France. Among other techniques, airborne geophysics is appropriate to quickly provide information on near surface, because of i) its high spatial coverage ii) the rapidity of acquisition and iii) the variety of available sensors (magnetic, spectral radiometry, electromagnetic...). Spectral radiometry data were collected with a line spacing of 1 km. This method provides maps of potassium (K), uranium (U) and thorium (Th) which are the only naturally occurring elements with direct or indirect radioisotopes that produce gamma rays of sufficient intensity to be measured at airborne survey heights. On the radiometric data we applied the HAC (Hierarchical Ascendant Classification) computation procedure: taking into account several variables, the statistical HAC method groups individuals based on their resemblance. Also in this study, calibrated Total Count channel (TCm) is compared to an estimated dose rate (TCe) computed from the measured radioelement abundances: TCe = 13.078 * K + 5.675 * U + 2.494 * Th. Our results show that the ratio TCe/TCm came out to be a good indicator of ground property changes within Sologne mixed sandy-clay environment. Processed geophysical data are cross-checked with geological data (from field observations) and field or laboratory measurements of mineralogical data

  17. Extensive 1-year survey of trace elements and compounds in the airborne suspended particulate matter in Cleveland, Ohio

    NASA Technical Reports Server (NTRS)

    King, R. B.; Fordyce, J. S.; Antoine, A. C.; Leibecki, H. F.; Neustadter, H. E.; Sidik, S. M.

    1976-01-01

    Concentrations of 75 chemical constituents in the airborne particulate matter were measured in Cleveland, Ohio, during 1971 and 1972. Values covering a 1-year period (45 to 50 sampling days) at each of 16 sites are presented for 60 elements. A lesser number of values is given for sulfate, nitrate, fluoride, acidity, 10 polynuclear aromatic hydrocarbon compounds, and the aliphatic hydrocarbon compounds as a group. Methods used included instrumental neutron activation, emission spectroscopy, gas chromatography, combustion techniques, and colorimetry. Uncertainties in the concentrations associated with the sampling procedures, the analysis methods, the use of several analytical facilities, and samples with concentrations below the detection limits are evaluated in detail. The data is discussed in relation to other studies and source origins. The trace constituent concentrations as a function of wind direction are used to suggest a practical method for air pollution source identification.

  18. Gravity-dependent signal path variation in a large VLBI telescope modelled with a combination of surveying methods

    NASA Astrophysics Data System (ADS)

    Sarti, Pierguido; Abbondanza, C.; Vittuari, L.

    2009-11-01

    The very long baseline interferometry (VLBI) antenna in Medicina (Italy) is a 32-m AZ-EL mount that was surveyed several times, adopting an indirect method, for the purpose of estimating the eccentricity vector between the co-located VLBI and Global Positioning System instruments. In order to fulfill this task, targets were located in different parts of the telescope’s structure. Triangulation and trilateration on the targets highlight a consistent amount of deformation that biases the estimate of the instrument’s reference point up to 1 cm, depending on the targets’ locations. Therefore, whenever the estimation of accurate local ties is needed, it is critical to take into consideration the action of gravity on the structure. Furthermore, deformations induced by gravity on VLBI telescopes may modify the length of the path travelled by the incoming radio signal to a non-negligible extent. As a consequence, differently from what it is usually assumed, the relative distance of the feed horn’s phase centre with respect to the elevation axis may vary, depending on the telescope’s pointing elevation. The Medicina telescope’s signal path variation Δ L increases by a magnitude of approximately 2 cm, as the pointing elevation changes from horizon to zenith; it is described by an elevation-dependent second-order polynomial function computed as, according to Clark and Thomsen (Techical report, 100696, NASA, Greenbelt, 1988), a linear combination of three terms: receiver displacement Δ R, primary reflector’s vertex displacement Δ V and focal length variations Δ F. Δ L was investigated with a combination of terrestrial triangulation and trilateration, laser scanning and a finite element model of the antenna. The antenna gain (or auto-focus curve) Δ G is routinely determined through astronomical observations. A surprisingly accurate reproduction of Δ G can be obtained with a combination of Δ V, Δ F and Δ R.

  19. Airborne Transparencies.

    ERIC Educational Resources Information Center

    Horne, Lois Thommason

    1984-01-01

    Starting from a science project on flight, art students discussed and investigated various means of moving in space. Then they made acetate illustrations which could be used as transparencies. The projection phenomenon made the illustrations look airborne. (CS)

  20. Mapping Ground Water in Three Dimensions - An Analysis of Airborne Geophysical Surveys of the Upper San Pedro River Basin, Cochise County, Southeastern Arizona

    USGS Publications Warehouse

    Wynn, Jeff

    2006-01-01

    This report summarizes the results of two airborne geophysical surveys conducted in the upper San Pedro Valley of southeastern Arizona in 1997 and 1999. The combined surveys cover about 1,000 square kilometers and extend from the Huachuca Mountains on the west to the Mule Mountains and Tombstone Hills on the east and from north of the Babocomari River to near the Mexican border on the south. The surveys included the acquisition of high-resolution magnetic data, which were used to map depth to the crystalline basement rocks underlying the sediments filling the basin. The magnetic inversion results show a complex basement morphology, with sediment thickness in the center of the valley ranging from ~237 meters beneath the city of Sierra Vista to ~1,500 meters beneath Huachuca City and the Palominas area near the Mexican border. The surveys also included acquisition of 60-channel time-domain electromagnetic (EM) data. Extensive quality analyses of these data, including inversion to conductivity vs. depth (conductivity-depth-transform or CDT) profiles and comparisons with electrical well logs, show that the electrical conductor mapped represents the subsurface water-bearing sediments throughout most of the basin. In a few places (notably the mouth of Huachuca Canyon), the reported water table lies above where the electrical conductor places it. These exceptions appear to be due to a combination of outdated water-table information, significant horizontal displacement between the wells and the CDT profiles, and a subtle calibration issue with the CDT algorithm apparent only in areas of highly resistive (very dry) overburden. These occasional disparities appear in less than 5 percent of the surveyed area. Observations show, however, that wells drilled in the thick unsaturated zone along the Huachuca Mountain front eventually intersect water, at which point the water rapidly rises high into the unsaturated zone within the wellbore. This rising of water in a wellbore implies

  1. Survey of whole air data from the second airborne Biomass Burning and Lightning Experiment using principal component analysis

    NASA Astrophysics Data System (ADS)

    Choi, Yunsoo; Elliott, Scott; Simpson, Isobel J.; Blake, Donald R.; Colman, Jonah J.; Dubey, Manvendra K.; Meinardi, Simone; Rowland, F. Sherwood; Shirai, Tomoko; Smith, Felisa A.

    2003-03-01

    Hydrocarbon and halocarbon measurements collected during the second airborne Biomass Burning and Lightning Experiment (BIBLE-B) were subjected to a principal component analysis (PCA), to test the capability for identifying intercorrelated compounds within a large whole air data set. The BIBLE expeditions have sought to quantify and understand the products of burning, electrical discharge, and general atmospheric chemical processes during flights arrayed along the western edge of the Pacific. Principal component analysis was found to offer a compact method for identifying the major modes of composition encountered in the regional whole air data set. Transecting the continental monsoon, urban and industrial tracers (e.g., combustion byproducts, chlorinated methanes and ethanes, xylenes, and longer chain alkanes) dominated the observed variability. Pentane enhancements reflected vehicular emissions. In general, ethyl and propyl nitrate groupings indicated oxidation under nitrogen oxide (NOx) rich conditions and hence city or lightning influences. Over the tropical ocean, methyl nitrate grouped with brominated compounds and sometimes with dimethyl sulfide and methyl iodide. Biomass burning signatures were observed during flights over the Australian continent. Strong indications of wetland anaerobics (methane) or liquefied petroleum gas leakage (propane) were conspicuous by their absence. When all flights were considered together, sources attributable to human activity emerged as the most important. We suggest that factor reductions in general and PCA in particular may soon play a vital role in the analysis of regional whole air data sets, as a complement to more familiar methods.

  2. Airborne forest fire research

    NASA Technical Reports Server (NTRS)

    Mattingly, G. S.

    1974-01-01

    The research relating to airborne fire fighting systems is reviewed to provide NASA/Langley Research Center with current information on the use of aircraft in forest fire operations, and to identify research requirements for future operations. A literature survey, interview of forest fire service personnel, analysis and synthesis of data from research reports and independent conclusions, and recommendations for future NASA-LRC programs are included.

  3. Airborne geophysical surveys used to delineate geological features associated with the M5.8 August 23, 2011 earthquake in Louisa County, Virginia

    NASA Astrophysics Data System (ADS)

    Shah, A. K.; Horton, J. W.; Gilmer, A. K.

    2012-12-01

    The M5.8 August 23, 2011 Louisa County, VA intraplate earthquake was felt by more people than any other in U.S. history not only because of population density, but also because of the associated geology. However, because limited bedrock exposures pose a challenge to geologic mapping efforts and the earthquake hypocenter is located at a depth of ~6 km, many questions remain. Potential field and gamma-ray spectrometry data thus provide key tools for imaging and understanding both shallow and deep subsurface geologic features. In July 2012, the USGS commissioned a high-resolution magnetic, gravity, and radiometric (gamma-ray spectrometry) survey over a 20 km x 25 km area covering the epicenters of the Louisa County earthquake and its aftershocks. The surveys were flown with 200-m line spacing from an altitude of ~120 m above ground, providing up to a 20-fold improvement over regional magnetic and radiometric coverage. Gravity was measured using Sander Geophysics' AIRGrav system, capable of resolving anomalies as narrow as 800 m for the given survey configuration; in most parts of the survey area the spacing of ground stations is ~10-20 stations per 100 km2. Preliminary magnetic and radiometric data show numerous NE-trending linear anomalies within this part of the Appalachian Piedmont Province. These metamorphic and igneous rocks exhibit 200-500 nT magnetic anomalies of width 300-1000 km that are likely to be generated by contrasts between various metavolcanic and metasedimentary rocks such as magnetite-bearing quartzites and felsic to mafic gneisses. Magnetic lows and radiometric highs are observed over several granitoid intrusive bodies such as the Ellisville pluton, the Falmouth Intrusive Suite, and a Paleozoic pegmatite belt. Derivative magnetic maps delineate numerous thin (< 250 m wide) N- NNW-trending linear anomalies, suggesting that Jurassic diabase dikes are much more common in this area than previously mapped. Radiometric data mostly correlate with mapped

  4. Advances and Best Practices in Airborne Gravimetry from the U.S. GRAV-D Project

    NASA Astrophysics Data System (ADS)

    Diehl, Theresa; Childers, Vicki; Preaux, Sandra; Holmes, Simon; Weil, Carly

    2013-04-01

    The Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project, an official policy of the U.S. National Geodetic Survey as of 2007, is working to survey the entire U.S. and its holdings with high-altitude airborne gravimetry. The goal of the project is to provide a consistent, high-quality gravity dataset that will become the cornerstone of a new gravimetric geoid and national vertical datum in 2022. Over the last five years, the GRAV-D project has surveyed more than 25% of the country, accomplishing almost 500 flights on six different aircraft platforms and producing more than 3.7 Million square km of data thus far. This wealth of experience has led to advances in the collection, processing, and evaluation of high-altitude (20,000 - 35,000 ft) airborne gravity data. This presentation will highlight the most important practical and theoretical advances of the GRAV-D project, giving an introduction to each. Examples of innovation include: 1. Use of navigation grade inertial measurement unit data and precise lever arm measurements for positioning; 2. New quality control tests and software for near real-time analysis of data in the field; 3. Increased accuracy of gravity post-processing by reexamining assumptions and simplifications that were inconsistent with a goal of 1 mGal precision; and 4. Better final data evaluation through crossovers, additional statistics, and inclusion of airborne data into harmonic models that use EGM08 as a base model. The increases in data quality that resulted from implementation of the above advances (and others) will be shown with a case study of the GRAV-D 2008 southern Alaska survey near Anchorage, over Cook Inlet. The case study's statistics and comparisons to global models illustrate the impact that these advances have had on the final airborne gravity data quality. Finally, the presentation will summarize the best practices identified by the project from its last five years of experience.

  5. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  6. A Flight Test of the Strapdown Airborne Gravimeter SGA-WZ in Greenland

    PubMed Central

    Zhao, Lei; Forsberg, René; Wu, Meiping; Olesen, Arne Vestergaard; Zhang, Kaidong; Cao, Juliang

    2015-01-01

    An airborne gravimeter is one of the most important tools for gravity data collection over large areas with mGal accuracy and a spatial resolution of several kilometers. In August 2012, a flight test was carried out to determine the feasibility and to assess the accuracy of the new Chinese SGA-WZ strapdown airborne gravimeter in Greenland, in an area with good gravity coverage from earlier marine and airborne surveys. An overview of this new system SGA-WZ is given, including system design, sensor performance and data processing. The processing of the SGA-WZ includes a 160 s length finite impulse response filter, corresponding to a spatial resolution of 6 km. For the primary repeated line, a mean r.m.s. deviation of the differences was less than 1.5 mGal, with the error estimate confirmed from ground truth data. This implies that the SGA-WZ could meet standard geophysical survey requirements at the 1 mGal level. PMID:26057039

  7. A Flight Test of the Strapdown Airborne Gravimeter SGA-WZ in Greenland.

    PubMed

    Zhao, Lei; Forsberg, René; Wu, Meiping; Olesen, Arne Vestergaard; Zhang, Kaidong; Cao, Juliang

    2015-01-01

    An airborne gravimeter is one of the most important tools for gravity data collection over large areas with mGal accuracy and a spatial resolution of several kilometers. In August 2012, a flight test was carried out to determine the feasibility and to assess the accuracy of the new Chinese SGA-WZ strapdown airborne gravimeter in Greenland, in an area with good gravity coverage from earlier marine and airborne surveys. An overview of this new system SGA-WZ is given, including system design, sensor performance and data processing. The processing of the SGA-WZ includes a 160 s length finite impulse response filter, corresponding to a spatial resolution of 6 km. For the primary repeated line, a mean r.m.s. deviation of the differences was less than 1.5 mGal, with the error estimate confirmed from ground truth data. This implies that the SGA-WZ could meet standard geophysical survey requirements at the 1 mGal level. PMID:26057039

  8. Airborne asbestos in buildings.

    PubMed

    Lee, R J; Van Orden, D R

    2008-03-01

    The concentration of airborne asbestos in buildings nationwide is reported in this study. A total of 3978 indoor samples from 752 buildings, representing nearly 32 man-years of sampling, have been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result the presence of asbestos-containing materials (ACM). The average concentration of all airborne asbestos structures was 0.01structures/ml (s/ml) and the average concentration of airborne asbestos > or = 5microm long was 0.00012fibers/ml (f/ml). For all samples, 99.9% of the samples were <0.01 f/ml for fibers longer than 5microm; no building averaged above 0.004f/ml for fibers longer than 5microm. No asbestos was detected in 27% of the buildings and in 90% of the buildings no asbestos was detected that would have been seen optically (> or = 5microm long and > or = 0.25microm wide). Background outdoor concentrations have been reported at 0.0003f/ml > or = 5microm. These results indicate that in-place ACM does not result in elevated airborne asbestos in building atmospheres approaching regulatory levels and that it does not result in a significantly increased risk to building occupants.

  9. Initial results of the 2011 Geoid Slope Validation Survey

    NASA Astrophysics Data System (ADS)

    Smith, D. A.

    2011-12-01

    The National Oceanic and Atmospheric Administration's (NOAA), National Geodetic Survey (NGS) has embarked on a ten year project called GRAV-D (Gravity for the Redefinition of the American Vertical Datum).The purpose of this project is to replace the current official vertical datum, NAVD 88 (the North American Vertical Datum of 1988) with a geopotential reference system based on a new survey of the gravity field and a gravimetric geoid. As part of GRAV-D, NGS plans to execute a set of "geoid validation surveys" at various locations of the country.These will be surveys designed to independently measure the geoid to provide a check against both the data and theory used to create the final gravimetric geoid which will be used in the geopotential reference system. The first of these surveys, known as the Geoid Slope Validation Survey of 2011 (GSVS11) was executed between July and October, 2011 in the west central region of Texas.The survey took place over a 330 kilometer line running more or less north-south from Austin to Corpus Christi, Texas.Measurements were taken at 220 marks (one per mile) and included static GPS, RTN GPS, geodetic leveling, astro-geodetic deflections of the vertical using the Swiss DIADEM camera, absolute gravity, gravity gradients and LIDAR.This region was chosen for many factors including the availability of GRAV-D airborne gravity over the area, its relatively low elevation (220 meter orthometric height max), its geoid slope (about 130 cm over 300 km), lack of significant topographic relief, lack of large forestation, availability of good roads, clarity of weather and lack of large water crossings. This talk will outline the initial results of the survey, specifically the comparison of various geoid slopes over this region:gravimetric geoid models (with and without airborne gravity), minimally constrained GPS and leveling and from astro-geodetic deflections of the vertical.

  10. Airborne Imagery

    NASA Technical Reports Server (NTRS)

    1983-01-01

    ATM (Airborne Thematic Mapper) was developed for NSTL (National Space Technology Companies) by Daedalus Company. It offers expanded capabilities for timely, accurate and cost effective identification of areas with prospecting potential. A related system is TIMS, Thermal Infrared Multispectral Scanner. Originating from Landsat 4, it is also used for agricultural studies, etc.

  11. Comparison of ground-based measurements of natural radiation to airborne radiation survey data on transects from coastal California to the Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Stoffer, P. W.; Hernández, L.; Messina, P.; Dearaujo, J.; Li, A.; Hicks, A.; White, L.

    2008-12-01

    Natural gamma radiation measurements were collected with a hand-held Geiger counter at nearly 400 locations on two general transects across the southwestern United States. The data are used to provide ground-truth comparison to published airborne radiation surveys of the region. The first transect was collected by high school students in the SF-ROCKS program at San Francisco State University in the summer of 2008 starting in San Francisco. Data were collected across the Sierra Nevada Range on I-80, and across Highway 50 in Nevada, and I-70 in Utah. Data were collected in and around Great Basin, Arches, Capitol Reef, Bryce, and Zion National Parks, and Grand Staircase-Escalante National Monument. A second transect extends from San José, California to Flagstaff, Arizona and includes the Mojave National Reserve, Death Valley region, and locations throughout the Navajo Reservation region in northern Arizona and western New Mexico. Radiation data (with GPS reference) were collected from all the major sedimentary rock formations and igneous rocks of the Colorado Plateau and from many igneous and metamorphic rocks throughout the Great Basin and southern California deserts. Anomalously high localized levels were noted in selected sedimentary units associated with uranium exploration targets in the Colorado Plateau region, and in caverns and rock fissures where radon gas (and accumulation of derivative fission products) are the inferred sources.

  12. Improving airborne strapdown vector gravimetry using stabilized horizontal components

    NASA Astrophysics Data System (ADS)

    Cai, Shaokun; Zhang, Kaidong; Wu, Meiping

    2013-11-01

    Integrating the deflections of the vertical along the flight line can yield geoid profiles which are valuable in the study of geodesy and geophysics, fortunately, the deflections can be measured directly by vector gravimetry. Airborne vector gravimetry using a Strapdown Inertial Navigation System and the Global Navigation Satellite System (SINS/GNSS) has shown promising results in previous studies. However, the quality of the SINS and GNSS is a major limitation; in particular, the attitude errors induced by the gyros will result in large measurement errors to the horizontal components of the gravity disturbance, and these measurement errors represent the behavior of low-frequency trend. An airborne vector gravimetry method used to remove the bias and low-frequency trends in the gravity disturbance estimated for each survey line has been developed. This method uses the horizontal components of the gravity disturbance computed from EGM2008 (Earth Gravitational Model 2008) as a reference. Firstly, the horizontal measurement results obtained from the gravimeter are divided into high- and low-frequency components according to the resolution of the EGM2008, and then, the bias and low-frequency trends of the low-frequency components are corrected using a linear fit to the EGM2008 reference data. Finally, the ultimate results can be acquired after combining the high-frequency components and the corrected low-frequency components. The data used was obtained from the SGA-WZ, which is the first strapdown airborne gravimeter developed in China. The results of this method are promising. The internal accuracy of the gravity disturbance's horizontal components for repeated survey lines exceeds 3.5 mGal, and the corresponding resolution is approximately 4.8 km based on 160-s data smoothing and an airplane averaging speed of approximately 216 km/h. After applying the WCF (Wavenumber Correlation Filter), the internal accuracy of the horizontal components exceeds 2 mGal. This can

  13. Gravity and Magnetic Survey of the Oaxaca-Juarez Terrane Boundary (Oaxaca Fault), Southern Mexico: Evidence for three Half Grabens

    NASA Astrophysics Data System (ADS)

    Campos-Enriquez, J. O.; Belmonte-Jimenez, S. I.; Ortega-Gutierrez, F.; Keppie-Moorhouse, J. D.; Martinez-Silva, J.; Martinez-Serrano, R.

    2007-05-01

    A geophysical survey of the Oaxaca Fault boundary between the Oaxaca (Oaxaquia) (Zapoteco) and Juarez (Cuicateco) terranes along the Etla and Zaachila valleys area, southern Mexico shows a series of NW-SE Bouguer and magnetic anomalies with stronger gradients towards the east. The basement from the Oaxaca terrane has a high density (2.8 gr/cm3 ) and magnetic susceptibility of up to 0.0051 cgs units, which contrast with the Juarez basement that has a lower density (2.67 gr/cm3) and a higher magnetic susceptibility (values ranging between 0.0025 to 0.0045 cgs units). The magnetic susceptibility is similar south of the Donaji fault. Interpretation of six combined gravity and magnetic NE-SW profiles perpendicular to the valleys indicates the presence of a composite depression comprising three N-S sub-basins with the Etla and Zachila sub-basins located at the northern and southern portions, respectively, separated by a third sub-basin relatively displaced westwards. They are bounded on the east by the steeply W-dipping Oaxaca master fault, and on the west by the gently E-dipping Huitzo-Zimatlan fault. Two interpretations are suggested for the southward continuation of the Oaxaca Fault: 1) it continues southwards at depth with the same strike. Together the Bouguer and total field magnetic anomalies suggest that the Oaxaca fault is continuous from Etla via Oaxaca City and Ocotlán de Morelos probably to Miahuatlán de Porfirio Díaz, and 2) it continues with the same strike but is displaced eastwards ~20 km along a sinistral transfer fault, which forms the northern boundary of the Zaachila sub-basin.

  14. Assessing modern ground survey methods and airborne laser scanning for digital terrain modelling: A case study from the Lake District, England

    NASA Astrophysics Data System (ADS)

    Gallay, Michal; Lloyd, Christopher D.; McKinley, Jennifer; Barry, Lorraine

    2013-02-01

    This paper compares the applicability of three ground survey methods for modelling terrain: one man electronic tachymetry (TPS), real time kinematic GPS (GPS), and terrestrial laser scanning (TLS). Vertical accuracy of digital terrain models (DTMs) derived from GPS, TLS and airborne laser scanning (ALS) data is assessed. Point elevations acquired by the four methods represent two sections of a mountainous area in Cumbria, England. They were chosen so that the presence of non-terrain features is constrained to the smallest amount. The vertical accuracy of the DTMs was addressed by subtracting each DTM from TPS point elevations. The error was assessed using exploratory measures including statistics, histograms, and normal probability plots. The results showed that the internal measurement accuracy of TPS, GPS, and TLS was below a centimetre. TPS and GPS can be considered equally applicable alternatives for sampling the terrain in areas accessible on foot. The highest DTM vertical accuracy was achieved with GPS data, both on sloped terrain (RMSE 0.16 m) and flat terrain (RMSE 0.02 m). TLS surveying was the most efficient overall but veracity of terrain representation was subject to dense vegetation cover. Therefore, the DTM accuracy was the lowest for the sloped area with dense bracken (RMSE 0.52 m) although it was the second highest on the flat unobscured terrain (RMSE 0.07 m). ALS data represented the sloped terrain more realistically (RMSE 0.23 m) than the TLS. However, due to a systematic bias identified on the flat terrain the DTM accuracy was the lowest (RMSE 0.29 m) which was above the level stated by the data provider. Error distribution models were more closely approximated by normal distribution defined using median and normalized median absolute deviation which supports the use of the robust measures in DEM error modelling and its propagation.

  15. MAJOR SOURCE OF SIDE-LOOKING AIRBORNE RADAR IMAGERY FOR RESEARCH AND EXPLORATION: THE U. S. GEOLOGICAL SURVEY.

    USGS Publications Warehouse

    Kover, Allan N.; Jones, John Edwin; ,

    1985-01-01

    The US Geological Survey (USGS) instituted a program in 1980 to acquire side-looking airbore radar (SLAR) data and make these data readily available to the public in a mosaic format comparable to the USGS 1:250,000-scale topographic map series. The SLAR data are also available as strip images at an acquisition scale of 1:250,000 or 1:400,000 (depending on the acquisition system), as a variety of print products and indexes, and in a limited amount in digital form on computer compatible tapes. Three different commercial X-band (3-cm) systems were used to acquire the imagery for producing the mosaics.

  16. Airborne geophysical surveys in the north-central region of Goias (Brazil): implications for radiometric characterization of tropical soils.

    PubMed

    Guimaraes, Suze Nei P; Hamza, Valiya M; da Silva, Joney Justo

    2013-02-01

    Progress obtained in analysis aerogammaspectrometric and aeromagnetic survey data for the north-central region of the state of Goias (Brazil) are presented. The results obtained have allowed not only determination of the abundances of naturally radioactive elements but also new insights into the processes that determine the radiometric characteristics of the main soil types. There are indications that the radioelement abundances of soils are not only related to their physical properties, but also chemical characteristics of source rocks from which they are derived. For example, oxisol soils derived from the felsic source rocks of the Mara Rosa and Green stone belts have equivalent uranium (eU) values higher than 1.7 ppm, while those derived from source rocks of the relatively more basic Uruaçu Group and sediment sequences of Proterozoic age are characterized by eU contents of less than 1 ppm. Oxisol soils of the Median massif, ultisol soils of the Paranoá, Canastra and Araxá Groups, cambisol soils of the Araí Group and plintosol soils of the Bambuí Group constitute an intermediate class with eU contents in the range of 1-1.3 ppm. Equivalent thorium abundances of soil types display similar trends, the range of variation being 4-16 ppm. Potassium abundances on the other hand are rather uniform with values in the range of 1-1.3%, the only exception being the sedimentary sequences of Proterozoic age, which has a mean value of 0.7%. These observations have been considered as indicative of characteristic features of tropical soils in the study area. In this context, we point out the possibility of using results of aerogammaspectrometry surveys as a convenient complementary tool in identifying geochemical zoning of soils in tropical environments. The ratios of eU/K are found to fall in the range of 1-1.7, which is typical of common soils. The ratios of eTh/K exhibit a relatively wide interval, with values in the range of 4-16. The ratios of eTh/eU are found to have

  17. Airborne geophysical surveys in the north-central region of Goias (Brazil): implications for radiometric characterization of tropical soils.

    PubMed

    Guimaraes, Suze Nei P; Hamza, Valiya M; da Silva, Joney Justo

    2013-02-01

    Progress obtained in analysis aerogammaspectrometric and aeromagnetic survey data for the north-central region of the state of Goias (Brazil) are presented. The results obtained have allowed not only determination of the abundances of naturally radioactive elements but also new insights into the processes that determine the radiometric characteristics of the main soil types. There are indications that the radioelement abundances of soils are not only related to their physical properties, but also chemical characteristics of source rocks from which they are derived. For example, oxisol soils derived from the felsic source rocks of the Mara Rosa and Green stone belts have equivalent uranium (eU) values higher than 1.7 ppm, while those derived from source rocks of the relatively more basic Uruaçu Group and sediment sequences of Proterozoic age are characterized by eU contents of less than 1 ppm. Oxisol soils of the Median massif, ultisol soils of the Paranoá, Canastra and Araxá Groups, cambisol soils of the Araí Group and plintosol soils of the Bambuí Group constitute an intermediate class with eU contents in the range of 1-1.3 ppm. Equivalent thorium abundances of soil types display similar trends, the range of variation being 4-16 ppm. Potassium abundances on the other hand are rather uniform with values in the range of 1-1.3%, the only exception being the sedimentary sequences of Proterozoic age, which has a mean value of 0.7%. These observations have been considered as indicative of characteristic features of tropical soils in the study area. In this context, we point out the possibility of using results of aerogammaspectrometry surveys as a convenient complementary tool in identifying geochemical zoning of soils in tropical environments. The ratios of eU/K are found to fall in the range of 1-1.7, which is typical of common soils. The ratios of eTh/K exhibit a relatively wide interval, with values in the range of 4-16. The ratios of eTh/eU are found to have

  18. Airborne laser topographic mapping results

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Collins, J. G.; Link, L. E.; Swift, R. N.; Butler, M. L.

    1984-01-01

    The results of terrain mapping experiments utilizing the National Aeronautics and Space Administration (NASA) Airborne Oceanographic Lidar (AOL) over forested areas are presented. The flight tests were conducted as part of a joint NASA/U.S. Army Corps of Engineers (CE) investigation aimed at evaluating the potential of an airborne laser ranging system to provide cross-sectional topographic data on flood plains that are difficult and expensive to survey using conventional techniques. The data described in this paper were obtained in the Wolf River Basin located near Memphis, TN. Results from surveys conducted under winter 'leaves off' and summer 'leaves on' conditions, aspects of day and night operation, and data obtained from decidous and coniferous tree types are compared. Data processing techniques are reviewed. Conclusions relative to accuracy and present limitations of the AOL, and airborne lidar systems in general, to terrain mapping over forested areas are discussed.

  19. Application of airborne gamma spectrometric survey data to estimating terrestrial gamma-ray dose rates: an example in California.

    PubMed

    Wollenberg, H A; Revzan, K L; Smith, A R

    1994-01-01

    We examined the applicability of radioelement data from the National Aerial Radiometric Reconnaissance, an element of the National Uranium Resource Evaluation, to estimate terrestrial gamma-ray absorbed dose rates, by comparing dose rates calculated from aeroradiometric surveys of uranium, thorium, and potassium concentrations with dose rates calculated from a radiogeologic data base and the distribution of lithologies in California. Gamma-ray dose rates increase generally from north to south following lithological trends, with low values of 25-30 nGy h-1 in the northernmost 1 x 2 degrees quadrangles between 41 and 42 degrees N to high values of 75-100 nGy h-1 in southeastern California. Lithologic-based estimates of mean dose rates in the quadrangles generally match those from aeroradiometric data, with statewide means of 63 and 60 nGy h-1, respectively. These are intermediate between a population-weighted global average of 51 nGy h-1 reported in 1982 by UNSCEAR and a weighted continental average of 70 nGy h-1, based on the global distribution of rock types. The concurrence of lithologically and aeroradiometrically determined dose rates in California, with its varied geology and topography encompassing settings representative of the continents, indicates that the National Aerial Radiometric Reconnaissance data are applicable to estimates of terrestrial absorbed dose rates from natural gamma emitters.

  20. Airborne gamma-ray spectrometer and magnetometer survey, Durango A, B, C, and D, Colorado. Volume I. Detail area. Final report

    SciTech Connect

    Not Available

    1983-01-01

    An airborne combined radiometric and magnetic survey was performed for the Department of Energy (DOE) over the Durango A, Durango B, Durango C, and Durango D Detail Areas of southwestern Colorado. The Durango A Detail Area is within the coverage of the Needle Mountains and Silverton 15' map sheets, and the Pole Creek Mountain, Rio Grande Pyramid, Emerald Lake, Granite Peak, Vallecito Reservoir, and Lemon Reservoir 7.5' map sheets of the National Topographic Map Series (NTMS). The Durango B Detail Area is within the coverage of the Silverton 15' map sheet and the Wetterhorn Peak, Uncompahgre Peak, Lake City, Redcloud Peak, Lake San Cristobal, Pole Creek Mountain, and Finger Mesa 7.5' map sheets of the NTMS. The Durango C Detail Area is within the coverage of the Platoro and Wolf Creek Pass 15' map sheets of the NTMS. The Durango D Detail Area is within the coverage of the Granite Lake, Cimarrona Peak, Bear Mountain, and Oakbrush Ridge 7.5' map sheets of the NTMS. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, gridded, and contoured to produce maps of the radiometric variables, uranium, potassium, and thorium; their ratios; and the residual magnetic field. These maps have been analyzed in order to produce a multi-variant analysis contour map based on the radiometric response of the individual geological units. A geochemical analysis has been performed, using the radiometric and magnetic contour maps, the multi-variant analysis map, and factor analysis techniques, to produce a geochemical analysis map for the area.

  1. Identification of subsurface brines in the McMurdo Dry Valleys, Antarctica, via an airborne EM resistivity survey

    NASA Astrophysics Data System (ADS)

    Foley, N.; Tulaczyk, S. M.; Auken, E.; Schamper, C.; Dugan, H. A.; Mikucki, J.; Virginia, R. A.; Doran, P. T.

    2015-12-01

    We used a helicopter-borne time domain electromagnetic resistivity survey to detect and map hypersaline brines beneath glaciers and permafrost in the McMurdo Dry Valleys (MDV). In the MDV, a substantially ice-free region of coastal Antarctica, liquid water is present at the surface only in summer streams, ice-covered lakes with brackish to hypersaline bottom waters, and at Blood Falls, a hypersaline discharge from Taylor Glacier. Beneath the surface, however, water can remain liquid at temperatures below 0 °C (and therefore at unexpectedly shallow depths) as a hypersaline brine. These brines, which are measured as zones of low resistivity in an otherwise high resistivity environment, are widespread in Taylor Valley, where they may connect lakes, subglacial waters, and the ocean. By using surface landscape characteristics - such as the presence of lakes, glaciers, or bare ground - we are able to compare changes in resistivity with depth. We find that in areas of surface permafrost (most of the MDV) there is a marked shift to low resistivity material around 200 m below the surface. At lakes, the stratified nature of their waters is detectable and sufficiently large lakes create taliks (unfrozen 'holes' in permafrost) that penetrate to the low resistivity zone around 200 m depth, suggesting connectivity through a regional aquifer. Underneath Taylor Glacier, we detect similar brines, which are the probable source for Blood Falls. These subglacial brines extend from the snout of Taylor Glacier (where they appear to connect to the hypersaline waters of West Lake Bonney) to the limit of our detection ability several kilometers up glacier where the ice became too thick for measurements. Our measurements are consistent with limited drilling done in the MDV during the 1970s and radar measurements taken more recently on Taylor Glacier. The transition to low resistivity at ~200 m depth occurs over a temperature range measured in boreholes of about -10 to -5 °C, which is

  2. Recent Advancements in Full Tensor Gravity Gradiometry for Resource Exploration: A Case study from West Africa - Birmian Greenstone Belt

    NASA Astrophysics Data System (ADS)

    Brewster, J.; Mataragio, J.

    2014-12-01

    Over the years significant progress has been made in understanding the regional geologic models of the Greenstone Belts associated with gold mineralization in the fields of exploration geochemistry, geophysics and data integration. Improved knowledge of the geological models together with advancements in exploration techniques have resulted in the discovery of many near surface, and relatively large gold mines around the world such as the Abitibi, Isua, Barberton, Lake Victoria, Sadiola, and Yatela. However, the search for new deposits becomes more difficult due to the fact that most easily detectable, near surface deposits have been discovered. Many of the remaining deposits tend to be remotely located and deep underground. Effective exploration for new economically viable deposits requires approaches that integrate multiple techniques capable of resolving smaller, deeper and remotely located resources. Gravity surveys have been widely used to map and define geometry and structure of greenstones belts at a regional scale. Structure and hydrothermally altered zones can be mapped, either directly by gravity in weathered environments or inferred in terrains where geological units of different density are offset and/or altered Gravity gradiometry is increasingly becoming a standard method of commercial minerals exploration. Gradiometry presents a significant increase in spatial resolution when compared to previous airborne gravity methods. Airborne full tensor gravity gradiometry surveys have been flown in the past for prospect-level gold exploration in Quebec, Nunavut, Nevada, Brazil, Mali, Zambia and New Zealand and Nevada. The application of airborne gravity gradiometry for prospect-level gold exploration over greenstone belts is discussed in this paper. The high resolution system capability to detect small, high frequency targets is the key for successful results. In addition, this paper presents and discusses data enhancement and 3D inversion results. It is

  3. Pseudo-thermal bar in poorly salted autumnal waters of the Gulf of Finland from satellite-airborne SAR/ASAR/ALSAR survey

    NASA Astrophysics Data System (ADS)

    Melentyev, Vladimir; Bobylev, Leonid; Tsepelev, Valery; Melentyev, Konstantin; Bednov, Petr

    2010-05-01

    The thermal bar (TB) was disclosed at the end of XIX century by F.A. Forel - world-famed founder of limnology, who studied different processes in Lake Leman from point of view ecology and hydrobiology. Forel supposed that TB arises in temperate large lakes for short period in spring in presence windless calm weather. Well-directed investigations of TB were recommenced in the beginning 1950-s at the Institute of Lake Research Russian Academy of Sciences by Dr A.I. Tikhomirov who had described also specific features of this phenomenon in fall. At the end of 1960-s we began examination thermal and ice regime of fresh and saltish inland water bodies with using remote sensing including multi-spectral airborne-satellite SLR/SAR/ASAR/ALSAR survey. And as result the possibility revealing TB parameters in fall season by low-frequency radar (ALSAR) installed onboard research aircraft was fixed documentally in the Lake Ladoga [Melentyev et. al., 2002]. According to [Tikhomirov, 1959] TB represents convergence zone around temperature of maximum density of fresh water + 4 °C (3, 98 °C, really). This narrow vertical "curtain" appears in littoral in spring owing to heating coastal waters, in fall - due to its cooling. TB divides large lakes and artificial reservoirs on two unequal thermic zones - heat-active (HAZ) and heat-inert (HIZ) that has different stratification of water temperature. Possible existence of TB in poorly salted sea waters was predicted by outstanding Russian oceanographer professor N. Zubov. Obviously firstly it was disclosed but without explanation the physics by [Bychkova, 1987]. Our own sub-satellite studies onboard nuclear icebreaker "Jamal" in western Arctic in fall 1996 allows reveal the TB on saltish waters in north-eastern "corner" of the Yenisei Gulf in mixing zone of marine and river waters. Long-lived converged zone that we call as pseudo-thermal bar (PTB) was marked by stationary banding narrow continuous rough strip that could be destroyed by

  4. World Gravity Map (WGM) Project: Objectives and Status

    NASA Astrophysics Data System (ADS)

    Bonvalot, S.; Briais, A.; Peyrefitte, A.; Biancale, R.; Gabalda, G.; Moreaux, G.; Sarrailh, M.; Fayard, T.

    2009-12-01

    The WGM project is a gravity mapping project undertaken under the aegis of the Commission for the Geological Map of the World (CGMW) to complement a set of global geological and geophysical digital maps published and updated by CGMW, such as the World Digital Magnetic Anomaly Map (WDMAM), released in 2007. This new global digital map aims to provide a high-resolution picture of the gravity anomalies of the world (free-air and topography-corrected Bouguer) based on the available information on the Earth gravity field, with the final objective to contribute to research and educational projects. The WGM project is conducted by the International Gravimetric Bureau (IGB), a center of the International Gravity Field Service (IGFS) of the International Association of Geodesy (IAG), with the support of the United Nations Educational Scientific and Cultural Organization (UNESCO). Major contributions to the WGM are provided by the EGM08 global model, recently released by the National Geospatial-Intelligence Agency (NGA, USA), as well as the new global marine gravity fields derived from satellite altimetry (DNSC08 computed at the Danish National Space Center, and V18.1 computed at Scripps Institution of Oceanography). The WGM also aims to improve the gravity anomalies at regional scale, using available products from recent regional compilations of land, marine and airborne surveys (possibly derived from BGI or other global or regional databases). As other geophysical maps published by CGMW, the WGM maps and digital products should be regularly updated according to the incoming gravity datasets. We present here the current status of the WGM project.

  5. Close-range airborne Structure-from-Motion Photogrammetry for high-resolution beach morphometric surveys: Examples from an embayed rotating beach

    NASA Astrophysics Data System (ADS)

    Brunier, Guillaume; Fleury, Jules; Anthony, Edward J.; Gardel, Antoine; Dussouillez, Philippe

    2016-05-01

    The field of photogrammetry has seen significant new developments essentially related to the emergence of new computer-based applications that have fostered the growth of the workflow technique called Structure-from-Motion (SfM). Low-cost, user-friendly SfM photogrammetry offers interesting new perspectives in coastal and other fields of geomorphology requiring high-resolution topographic data. The technique enables the construction of topographic products such as digital surface models (DSMs) and orthophotographs, and combines the advantages of the reproducibility of GPS surveys and the high density and accuracy of airborne LiDAR, but at very advantageous cost compared to the latter. Three SfM-based photogrammetric experiments were conducted on the embayed beach of Montjoly in Cayenne, French Guiana, between October 2013 and 2014, in order to map morphological changes and quantify sediment budgets. The beach is affected by a process of rotation induced by the alongshore migration of mud banks from the mouths of the Amazon River that generate spatial and temporal changes in wave refraction and incident wave angles, thus generating the reversals in longshore drift that characterise this process. Sub-vertical aerial photographs of the beach were acquired from a microlight aircraft that flew alongshore at low elevation (275 m). The flight plan included several parallel flight axes with an overlap of 85% between pictures in the lengthwise direction and 50% between paths. Targets of 40 × 40 cm, georeferenced by RTK-DGPS, were placed on the beach, spaced 100 m apart. These targets served in optimizing the model and in producing georeferenced 3D products. RTK-GPS measurements of random points and cross-shore profiles were used to validate the photogrammetry results and assess their accuracy. We produced dense point clouds with 150 to 200 points/m², from which we generated DSMs and orthophotos with respective resolutions of 10 cm and 5 cm. Compared to the GPS control

  6. High-resolution digital elevation model of lower Cowlitz and Toutle Rivers, adjacent to Mount St. Helens, Washington, based on an airborne lidar survey of October 2007

    USGS Publications Warehouse

    Mosbrucker, Adam

    2015-01-01

    The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. Lava domes were extruded during the subsequent eruptive periods of 1980–1986 and 2004–2008. More than three decades after the emplacement of the 1980 debris avalanche, high sediment production persists in the Toutle River basin, which drains the northern and western flanks of the volcano. Because this sediment increases the risk of flooding to downstream communities on the Toutle and lower Cowlitz Rivers, the U.S. Army Corps of Engineers (USACE), under the direction of Congress to maintain an authorized level of flood protection, continues to monitor and mitigate excess sediment in North and South Fork Toutle River basins to help reduce this risk and to prevent sediment from clogging the shipping channel of the Columbia River. From October 22–27, 2007, Watershed Sciences, Inc., under contract to USACE, collected high-precision airborne lidar (light detection and ranging) data that cover 273 square kilometers (105 square miles) of lower Cowlitz and Toutle River tributaries from the Columbia River at Kelso, Washington, to upper North Fork Toutle River (below the volcano's edifice), including lower South Fork Toutle River. These data provide a digital dataset of the ground surface, including beneath forest cover. Such remotely sensed data can be used to develop sediment budgets and models of sediment erosion, transport, and deposition. The U.S. Geological Survey (USGS) used these lidar data to develop digital elevation models (DEMs) of the study area. DEMs are fundamental to monitoring natural hazards and studying volcanic landforms, fluvial and glacial geomorphology, and surface geology. Watershed Sciences, Inc., provided files in the LASer (LAS) format containing laser returns that had been filtered, classified, and georeferenced. The USGS produced a hydro-flattened DEM from ground-classified points at

  7. High-resolution digital elevation model of Mount St. Helens crater and upper North Fork Toutle River basin, Washington, based on an airborne lidar survey of September 2009

    USGS Publications Warehouse

    Mosbrucker, Adam

    2014-01-01

    The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. Lava domes were extruded during the subsequent eruptive periods of 1980–1986 and 2004–2008. More than three decades after the emplacement of the 1980 debris avalanche, high sediment production persists in the North Fork Toutle River basin, which drains the northern flank of the volcano. Because this sediment increases the risk of flooding to downstream communities on the Toutle and Cowlitz Rivers, the U.S. Army Corps of Engineers (USACE), under the direction of Congress to maintain an authorized level of flood protection, built a sediment retention structure on the North Fork Toutle River in 1989 to help reduce this risk and to prevent sediment from clogging the shipping channel of the Columbia River. From September 16–20, 2009, Watershed Sciences, Inc., under contract to USACE, collected high-precision airborne lidar (light detection and ranging) data that cover 214 square kilometers (83 square miles) of Mount St. Helens and the upper North Fork Toutle River basin from the sediment retention structure to the volcano's crater. These data provide a digital dataset of the ground surface, including beneath forest cover. Such remotely sensed data can be used to develop sediment budgets and models of sediment erosion, transport, and deposition. The U.S. Geological Survey (USGS) used these lidar data to develop digital elevation models (DEMs) of the study area. DEMs are fundamental to monitoring natural hazards and studying volcanic landforms, fluvial and glacial geomorphology, and surface geology. Watershed Sciences, Inc., provided files in the LASer (LAS) format containing laser returns that had been filtered, classified, and georeferenced. The USGS produced a hydro-flattened DEM from ground-classified points at Castle, Coldwater, and Spirit Lakes. Final results averaged about five laser last

  8. Requirements for airborne vector gravimetry

    NASA Technical Reports Server (NTRS)

    Schwarz, K. P.; Colombo, O.; Hein, G.; Knickmeyer, E. T.

    1992-01-01

    The objective of airborne vector gravimetry is the determination of the full gravity disturbance vector along the aircraft trajectory. The paper briefly outlines the concept of this method using a combination of inertial and GPS-satellite data. The accuracy requirements for users in geodesy and solid earth geophysics, oceanography and exploration geophysics are then specified. Using these requirements, accuracy specifications for the GPS subsystem and the INS subsystem are developed. The integration of the subsystems and the problems connected with it are briefly discussed and operational methods are indicated that might reduce some of the stringent accuracy requirements.

  9. Porous gravity currents: A survey to determine the joint influence of fluid rheology and variations of medium properties

    NASA Astrophysics Data System (ADS)

    Ciriello, Valentina; Longo, Sandro; Chiapponi, Luca; Di Federico, Vittorio

    2016-06-01

    We develop a model to grasp the combined effect of rheology and spatial stratifications on two-dimensional non-Newtonian gravity-driven flow in porous media. We consider a power-law constitutive equation for the fluid, and a monomial variation of permeability and porosity along the vertical direction (transverse to the flow) or horizontal direction (parallel to the flow). Under these assumptions, similarity solutions are derived in semi-analytical form for thin gravity currents injected into a two-dimensional porous medium and having constant or time-varying volume. The extent and shape of the porous domain affected by the injection is significantly influenced by the interplay of model parameters. These describe the fluid (flow behaviour index n), the spatial heterogeneity (coefficients β, γ, δ, ω for variations of permeability and porosity in the horizontal or vertical direction), and the type of release (volume exponent α). Theoretical results are validated against two sets of experiments with α = 1 (constant inflow) conducted with a stratified porous medium (simulated by superimposing layers of glass beads of different diameter) and a Hele-Shaw analogue for power-law fluid flow, respectively. In the latter case, a recently established Hele-Shaw analogy is extended to the variation of properties parallel to the flow direction. Comparison with experimental results shows that the proposed model is able to capture the propagation of the current front and the current profile.

  10. Integrated magnetic, gravity, and GPR surveys to locate the probable source of hydrocarbon contamination in Sharm El-Sheikh area, south Sinai, Egypt

    NASA Astrophysics Data System (ADS)

    Morsy, Mona; Rashed, Mohamed

    2013-01-01

    Sharm El-Sheikh waters were suddenly hit by hydrocarbon spills which created a serious threat to the prosperous tourism industry in and around the city. Analysis of soil samples, water samples, and seabed samples collected in and around the contaminated bay area showed anomalous levels of hydrocarbons. An integrated geophysical investigation, using magnetic, gravity, and ground penetrating radar geophysical tools, was conducted in the headland overlooking the contaminated bay in order to delineate the possible subsurface source of contamination. The results of the geophysical investigations revealed three underground manmade reinforced concrete tanks and a complicated network of buried steel pipes in addition to other unidentified buried objects. The depths and dimensions of the discovered objects were determined. Geophysical investigations also revealed the presence of a north-south oblique slip fault running through the eastern part of the studied area. Excavations, conducted later on, confirmed the presence of one of the tanks delineated by the geophysical surveys.

  11. Ground Gravity, Magnetic and Electromagnetic Surveys on a Crater on Basalt of Bajada del Diablo Astrobleme-Strewn Field

    NASA Astrophysics Data System (ADS)

    Acevedo, R. D.; Prezzi, C.; Orgeira, M. J.; Rocca, M.; Martínez, O.; Ponce, J. F.; Corbella, H.; Rabassa, J.; González-Guillot, M.; Subías, I.

    2014-09-01

    With the aim of further investigate the circular structures from Bajada del Diablo, we carried out geophysics surveys and we conclude that the geophysical features could be satisfactorily explained assuming an extra-terrestrial projectile impact.

  12. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  13. Recent Advances in Conformal Gravity

    NASA Astrophysics Data System (ADS)

    O'Brien, James; Chaykov, Spasen

    2016-03-01

    In recent years, significant advances have been made in alternative gravitational theories. Although MOND remains the leading candidate among the alternative models, Conformal Gravity has been studied by Mannheim and O'Brien to solve the rotation curve problem without the need for dark matter. Recently, Mannheim, O'Brien and Chaykov have begun solving other gravitational questions in Conformal Gravity. In this presentation, we highlight the new work of Conformal Gravity's application to random motions of clusters (the original Zwicky problem), gravitational bending of light, gravitational lensing and a very recent survey of dwarf galaxy rotation curves. We will show in each case that Conformal Gravity can provide an accurate explanation and prediction of the data without the need for dark matter. Coupled with the fact that Conformal Gravity is a fully re-normalizable metric theory of gravity, these results help to push Conformal Gravity onto a competitive stage against other alternative models.

  14. Gravity Waves

    Atmospheric Science Data Center

    2013-04-19

    article title:  Gravity Waves Ripple over Marine Stratocumulus Clouds ... Imaging SpectroRadiometer (MISR), a fingerprint-like gravity wave feature occurs over a deck of marine stratocumulus clouds. Similar ... that occur when a pebble is thrown into a still pond, such "gravity waves" sometimes appear when the relatively stable and stratified air ...

  15. Neotectonic implications by geophysical surveys of topographic features identified by Airborne Laser Scanning in the Neusiedlersee/Ferto area (Austria/Hungary)

    NASA Astrophysics Data System (ADS)

    Timár, G.; Székely, B.; Zámolyi, A.; Houseman, G.; Stuart, G.; Grasemann, B.; Dombrádi, E.; Galsa, A.; Spahic, D.; Draganits, E.

    2009-04-01

    The area around the Lake Neudsiedlersee (Lake Fertő in Hungarian) was analysed to understand its neotectonic activity and gather possible explanations of the features of the topography and microtopography. The area consists of two, considerably different parts in terms of topography and geomorphology. The western and north-western shores of the lake are connected to the Leitha Mts., a low ridge (its relative height is about 300 meters) that connects the Alpine orogen in the SW with the Carpathians to NE bounded by active strike-slip faulting. In this part of the area, several outcrops were investigated, of which the one at St. Margarethen was systematically measured by multielectric sounding and GPR, and an other one at St. Georgen, north of Eisenstadt, was used for auxiliary data gathering. The eastern and southern shores, belonging to the Pannonian Basin, are mostly flatlands, parts of the Little Hungarian Plain with extremely low relief and no real natural drainage. The small variations of the surface altitude (less than ten meters), referred to as microtopography here, are due to elongated ridges and extremely shallow perennial or temporal playa lakes. In order to understand better the subsurface structure, a multimethod approach has been applied. Geophysical survey methods (vertical electric sounding, land seismics, gravity measurements) were carried out to describe the layer structure of this area, especially a zone, north of Illmitz, connected to interesting elements of microtopography. The identification of microtopographic features were carried out using high resolution digital elevation datasets, derived from Aerial Laser Scannings (ALS). Seismic measurements were carried out also in the lake itself to understand the structural geological settings of the lake bottom to the depth of ca. 50 meters. All of these measurements were made in the framework of a common student fieldwork of the Eötvös University, the University of Leeds and the University of

  16. The Lunar Scout Program: An international program to survey the Moon from orbit for geochemistry, mineralogy, imagery, geodesy, and gravity

    NASA Technical Reports Server (NTRS)

    Morrison, Donald A. (Editor)

    1994-01-01

    The Lunar Scout Program was one of a series of attempts by NASA to develop and fly an orbiting mission to the moon to collect geochemical, geological, and gravity data. Predecessors included the Lunar Observer, the Lunar Geochemical Orbiter, and the Lunar Polar Orbiter - missions studied under the auspices of the Office of Space Science. The Lunar Scout Program, however, was an initiative of the Office of Exploration. It was begun in late 1991 and was transferred to the Office of Space Science after the Office of Exploration was disbanded in 1993. Most of the work was done by a small group of civil servants at the Johnson Space Center; other groups also responsible for mission planning included personnel from the Charles Stark Draper Laboratories, the Lawrence Livermore National Laboratory, Boeing, and Martin Marietta. The Lunar Scout Program failed to achieve new start funding in FY 93 and FY 94 as a result of budget downturns, the de-emphasis of the Space Exploration Initiative, and the fact that lunar science did not rate as high a priority as other planned planetary missions, and was cancelled. The work done on the Lunar Scout Program and other lunar orbiter studies, however, represents assets that will be useful in developing new approaches to lunar orbit science.

  17. The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions at z ˜ 1.4

    NASA Astrophysics Data System (ADS)

    Okumura, Teppei; Hikage, Chiaki; Totani, Tomonori; Tonegawa, Motonari; Okada, Hiroyuki; Glazebrook, Karl; Blake, Chris; Ferreira, Pedro G.; More, Surhud; Taruya, Atsushi; Tsujikawa, Shinji; Akiyama, Masayuki; Dalton, Gavin; Goto, Tomotsugu; Ishikawa, Takashi; Iwamuro, Fumihide; Matsubara, Takahiko; Nishimichi, Takahiro; Ohta, Kouji; Shimizu, Ikkoh; Takahashi, Ryuichi; Takato, Naruhisa; Tamura, Naoyuki; Yabe, Kiyoto; Yoshida, Naoki

    2016-06-01

    We measure the redshift-space correlation function from a spectroscopic sample of 2783 emission line galaxies from the FastSound survey. The survey, which uses the Subaru Telescope and covers a redshift range of 1.19 < z < 1.55, is the first cosmological study at such high redshifts. We detect clear anisotropy due to redshift-space distortions (RSD) both in the correlation function as a function of separations parallel and perpendicular to the line of sight and its quadrupole moment. RSD has been extensively used to test general relativity on cosmological scales at z < 1. Adopting a ΛCDM cosmology with the fixed expansion history and no velocity dispersion (σv = 0), and using the RSD measurements on scales above 8 h-1 Mpc, we obtain the first constraint on the growth rate at the redshift, f (z)σ8(z) = 0.482 ± 0.116 at z ˜ 1.4 after marginalizing over the galaxy bias parameter b(z)σ8(z). This corresponds to 4.2 σ detection of RSD. Our constraint is consistent with the prediction of general relativity fσ8 ˜ 0.392 within the 1 σ confidence level. When we allow σv to vary and marginalize over it, the growth rate constraint becomes fσ _8=0.494^{+0.126}_{-0.120}. We also demonstrate that by combining with the low-z constraints on fσ8, high-z galaxy surveys like the FastSound can be useful to distinguish modified gravity models without relying on CMB anisotropy experiments.

  18. Improving New Zealand's Geoid-Based Vertical Datum with Airborne Gravimetry

    NASA Astrophysics Data System (ADS)

    Amos, M.; McCubbine, J.; Winefield, R.

    2014-12-01

    Land Information New Zealand (LINZ) is midway through a project to improve the accuracy of the quasigeoid-based New Zealand Vertical Datum 2009 to 3cm in developed areas. Much of the geoid accuracy improvement is expected to be attributed to the incorporation of recent airborne gravity data, re-analysis of existing terrestrial gravity observations and newer satellite gravity models. In this paper we outline the results of the recent airborne gravity collection campaigns (2013-14) over New Zealand and their contribution to an improved national geoid. The airborne data and the resultant geoid model are validated by comparisons with terrestrial gravity and GNSS-levelling data along two 35-50 km calibration lines. We also evaluate the potential of the resulting geoid to form the basis of the updated New Zealand Vertical Datum.

  19. Effects of modified gravity in galactic clustering

    NASA Astrophysics Data System (ADS)

    Verma, Murli; Krishna Yadav, Bal

    2016-07-01

    We discuss the distinct effects of the modified gravity, especially f(R) gravity in structure formation. The small redshift as well as high redshift epochs are studied with a potential set of diagnostics distinguishing between the standard general relativistic and the modified gravity. These diagnostics are further put to test against the observations obtained in clustering surveys.

  20. Constraining f (R ) Gravity Theory Using Weak Lensing Peak Statistics from the Canada-France-Hawii-Telescope Lensing Survey

    NASA Astrophysics Data System (ADS)

    Liu, Xiangkun; Li, Baojiu; Zhao, Gong-Bo; Chiu, Mu-Chen; Fang, Wei; Pan, Chuzhong; Wang, Qiao; Du, Wei; Yuan, Shuo; Fu, Liping; Fan, Zuhui

    2016-07-01

    In this Letter, we report the observational constraints on the Hu-Sawicki f (R ) theory derived from weak lensing peak abundances, which are closely related to the mass function of massive halos. In comparison with studies using optical or x-ray clusters of galaxies, weak lensing peak analyses have the advantages of not relying on mass-baryonic observable calibrations. With observations from the Canada-France-Hawaii-Telescope Lensing Survey, our peak analyses give rise to a tight constraint on the model parameter |fR 0| for n =1 . The 95% C.L. is log10|fR 0|<-4.82 given WMAP9 priors on (Ωm , As ). With Planck15 priors, the corresponding result is log10|fR 0|<-5.16 .

  1. Constraining f(R) Gravity Theory Using Weak Lensing Peak Statistics from the Canada-France-Hawaii-Telescope Lensing Survey.

    PubMed

    Liu, Xiangkun; Li, Baojiu; Zhao, Gong-Bo; Chiu, Mu-Chen; Fang, Wei; Pan, Chuzhong; Wang, Qiao; Du, Wei; Yuan, Shuo; Fu, Liping; Fan, Zuhui

    2016-07-29

    In this Letter, we report the observational constraints on the Hu-Sawicki f(R) theory derived from weak lensing peak abundances, which are closely related to the mass function of massive halos. In comparison with studies using optical or x-ray clusters of galaxies, weak lensing peak analyses have the advantages of not relying on mass-baryonic observable calibrations. With observations from the Canada-France-Hawaii-Telescope Lensing Survey, our peak analyses give rise to a tight constraint on the model parameter |f_{R0}| for n=1. The 95% C.L. is log_{10}|f_{R0}|<-4.82 given WMAP9 priors on (Ω_{m}, A_{s}). With Planck15 priors, the corresponding result is log_{10}|f_{R0}|<-5.16. PMID:27517761

  2. Constraining f(R) Gravity Theory Using Weak Lensing Peak Statistics from the Canada-France-Hawaii-Telescope Lensing Survey.

    PubMed

    Liu, Xiangkun; Li, Baojiu; Zhao, Gong-Bo; Chiu, Mu-Chen; Fang, Wei; Pan, Chuzhong; Wang, Qiao; Du, Wei; Yuan, Shuo; Fu, Liping; Fan, Zuhui

    2016-07-29

    In this Letter, we report the observational constraints on the Hu-Sawicki f(R) theory derived from weak lensing peak abundances, which are closely related to the mass function of massive halos. In comparison with studies using optical or x-ray clusters of galaxies, weak lensing peak analyses have the advantages of not relying on mass-baryonic observable calibrations. With observations from the Canada-France-Hawaii-Telescope Lensing Survey, our peak analyses give rise to a tight constraint on the model parameter |f_{R0}| for n=1. The 95% C.L. is log_{10}|f_{R0}|<-4.82 given WMAP9 priors on (Ω_{m}, A_{s}). With Planck15 priors, the corresponding result is log_{10}|f_{R0}|<-5.16.

  3. Venus gravity

    NASA Technical Reports Server (NTRS)

    Reasenberg, Robert D.

    1993-01-01

    The anomalous gravity field of Venus shows high correlation with surface features revealed by radar. We extract gravity models from the Doppler tracking data from the Pioneer Venus Orbiter (PVO) by means of a two-step process. In the first step, we solve the nonlinear spacecraft state estimation problem using a Kalman filter-smoother. The Kalman filter was evaluated through simulations. This evaluation and some unusual features of the filter are discussed. In the second step, we perform a geophysical inversion using a linear Bayesian estimator. To allow an unbiased comparison between gravity and topography, we use a simulation technique to smooth and distort the radar topographic data so as to yield maps having the same characteristics as our gravity maps. The maps presented cover 2/3 of the surface of Venus and display the strong topography-gravity correlation previously reported. The topography-gravity scatter plots show two distinct trends.

  4. Aircraft Positioning for Airborne Gravimetry: GRAV-D's 'Kinematic GPS Processing Challenge' (Invited)

    NASA Astrophysics Data System (ADS)

    Damiani, T.; Bilich, A. L.; Mader, G. L.

    2013-12-01

    The National Geodetic Survey's (NGS's) Gravity for the Redefinition of the American Vertical Datum (GRAV-D) program will collect airborne gravity data across the entire U.S. and its holdings by 2022 to support a new national vertical datum. By July 2013, >26% of data collection was complete. To achieve the best airborne gravity data accuracy possible, the GPS-derived position, velocity, and accelerations of the aircraft must also be highly accurate. In Fall 2010, NGS issued the 'Kinematic GPS Challenge', asking for kinematic GPS experts to voluntarily process dual-frequency GPS data from two 2008 GRAV-D flights over Louisiana. The Challenge data have: long baselines (> 500 km), high altitudes (35,000 ft), high speeds (280 kts), and difficult locations (half of each flight is over the Gulf of Mexico). For both flights, 1s GPS receiver data was available from: the aircraft, nearby CORS stations, and an NGS-run Ashtech GPS base station at the New Orleans airport. The goal of the Challenge was to compare the position results of a variety of methods, and to compare the airborne gravity calculated using each of those position solutions. In response to the Challenge, eighteen position results from twelve contributors (including two from NGS), using both differential and PPP methods, were submitted. Initial analysis of submitted solutions showed many of the position solutions were contaminated by a 'sawtooth' pattern. Eventually, the 'sawtooth' was attributed to problems with the Trimble receiver in the aircraft. Despite the receiver problem and after removal of two outlier solutions, the submitted position solutions were different by no more than +/- 0.25 m in X, Y, and Z. The differential and PPP solutions were indistinguishable from one another, even when the aircraft was over 500 km away from the airport. The two best gravity results came from position solutions that incorporated smoothing into their processing. For the high-noise flight, NGS' preferred GPS+IMU loosely

  5. A decade of sea ice thickness mapping by airborne lidar between Greenland and the North Pole

    NASA Astrophysics Data System (ADS)

    Hvidegaard, S. M.; Forsberg, R.; Skourup, H.; Stenseng, L.; Hanson, S.

    2007-12-01

    Airborne laser altimetry provides a direct measurement of sea ice freeboard, when combined with a precise geoid model and a lowest-level filtering algorithm to take into account residual errors in GPS-positioning, ocean dynamic topography, tides etc. Using swath laser scanning, the method additionally gives detailed information on the geometry of leads, ridges and the distribution of thin ice and open water. The conversion of sea ice freeboard heights to thickness is based on the assumption of equilibrium, with major errors sources relating to snow depth and density of sea ice. In the paper we describe results of measurements with airborne laser north of Greenland, Ellesmere Island and in the Fram Strait region, carried out on a yearly basis since 1998, in the first years using a single beam laser, and since 2001 using swath laser scanning giving a resolution of approximately 1 m in the ice features. The campaigns have mostly been done in the spring period, typically in connection with airborne gravity surveys or CryoSat calibration and validation activities. Observed secular changes in the sea ice freeboard heights are masked by limited spatial and temporal extent of campaigns, as well as interannual variability in the sea ice regime of the region. To address the error sources in the lidar thickness determination, a number of in-situ and helicopter EM comparisons have been carried out, e.g latest in April 2007 around the Tara drifting station beyond the North Pole, as part of the Damocles project. In cooperation with ESA and APL, coincident Ku-band radar and laser systems have also been flown, giving a unique opportunity for airborne measurement of snow depth as well.

  6. Gravity investigations

    SciTech Connect

    Healey, D.L.

    1983-12-31

    A large density contrast exists between the Paleozoic rocks (including the rocks of Climax stock) and less dense, Tertiary volcanic rocks and alluvium. This density contrast ranges widely, and herein for interpretive purposes, is assumed to average 0.85 Mg/m{sup 3} (megagrams per cubic meter). The large density contrast makes the gravity method a useful tool with which to study the interface between these rock types. However, little or no density contrast is discernible between the sedimentary Paleozoic rocks that surround the Climax stock and the intrusive rocks of the stock itself. Therefore the gravity method can not be used to define the configuration of the stock. Gravity highs coincide with outcrops of the dense Paleozoic rocks, and gravity lows overlie less-dense Tertiary volcanic rocks and Quaternary alluvium. The positions of three major faults (Boundary, Yucca, and Butte faults) are defined by steep gravity gradients. West of the Climax stock, the Tippinip fault has juxtaposed Paleozoic rocks of similar density, and consequently, has no expression in the gravity data in that area. The gravity station spacing, across Oak Spring Butte, is not sufficient to adequately define any gravity expression of the Tippinip fault. 18 refs., 5 figs.

  7. Principal facts for gravity stations for the Central Arizona Project

    USGS Publications Warehouse

    Peterson, Donald L.

    1972-01-01

    Observed gravity values, station locations, terrain corrections, and Bouguer gravity data are provided in tabular form for approximately 2460 gravity observations in south-central Arizona. "These data were used in preparation of -- Peterson, Donald L., 1968, Bouguer gravity map of parts of Maricopa, Pima, Pinal, and Yuma Counties, Arizona: U.S. Geol. Survey Geonhvs. Inv. Map GP-615.

  8. On the use of L-band multipolarization airborne SAR for surveys of crops, vineyards, and orchards in a California irrigated agricultural region

    NASA Technical Reports Server (NTRS)

    Paris, J. F.

    1985-01-01

    The airborne L-band synthetic aperture radar (SAR) collected multipolarization calibrated image data over an irrigated agricultural test site near Fresno, CA, on March 6, 1984. The conclusions of the study are as follows: (1) the effects of incidence angle on the measured backscattering coefficients could be removed by using a correction factor equal to the secant of the angle raised to the 1.4 power, (2) for this scene and time of year, the various polarization channels were highly correlated such that the use of more than one polarization added little to the ability of the radar to discriminate vegetation type or condition; the exception was barley which separated from vineyards only when a combination of like and cross polarization data were used (polarization was very useful for corn identification in fall crops), (3) an excellent separation between herbaceous vegetation (alfalfa, barley, and oats) or bare fields and trees in orchards existed in brightness was well correlated to alfalfa height or biomass, especially for the HH polarization combination, (5) vineyards exhibited a narrow range of brightnesses with no systematic effects of type or number of stakes nor of number of wires in the trellises nor of the size of the vines, (6) within the orchard classes, areal biomass characterized by basal area differences caused radar image brightness differences for small to medium trees but not for medium to large trees.

  9. Extending airborne electromagnetic surveys for regional active layer and permafrost mapping with remote sensing and ancillary data, Yukon Flats ecoregion, central Alaska

    USGS Publications Warehouse

    Pastick, Neal J.; Jorgenson, M. Torre; Wylie, Bruce K.; Minsley, Burke J.; Ji, Lei; Walvoord, Michelle A.; Smith, Bruce D.; Abraham, Jared D.; Rose, Joshua R.

    2013-01-01

    Machine-learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method of extrapolation (r = 0.86) used subsurface resistivity, Landsat Thematic Mapper (TM) at-sensor reflectance, thermal, TM-derived spectral indices, digital elevation models and other relevant spatial data to estimate near-surface (0–2.6-m depth) resistivity at 30-m resolution. A piecewise regression model (r = 0.82) and a presence/absence decision tree classification (accuracy of 87%) were used to estimate active-layer thickness (ALT) (< 101 cm) and the probability of near-surface (up to 123-cm depth) permafrost occurrence from field data, modelled near-surface (0–2.6 m) resistivity, and other relevant remote sensing and map data. At site scale, the predicted ALTs were similar to those previously observed for different vegetation types. At the landscape scale, the predicted ALTs tended to be thinner on higher-elevation loess deposits than on low-lying alluvial and sand sheet deposits of the Yukon Flats. The ALT and permafrost maps provide a baseline for future permafrost monitoring, serve as inputs for modelling hydrological and carbon cycles at local to regional scales, and offer insight into the ALT response to fire and thaw processes.

  10. Modeling Airborne Gravimetry with High-Degree Harmonic Expansions

    NASA Astrophysics Data System (ADS)

    Holmes, Simon; Wang, Yan Ming; Roman, Daniel

    2010-05-01

    Since its official unveiling at the 2008 General Assembly of the European Geosciences Union, EGM2008 has demonstrated that high-degree harmonic expansions constitute a useful and effective final representation for high-resolution global gravitational models. However, such expansions also provide a versatile means of capturing (modeling), inter-comparing, and optimally combining local and regional high-resolution terrestrial data sets of different types. Here we present a general recipe for using high-degree expansions to capture, downward-continue and assimilate airborne survey data. This approach relies on the production of two ‘competing' high-degree expansions. A first, ‘terrestrial-only' expansion incorporates EGM2008 globally, and high-resolution terrestrial gravimetry regionally. This expansion can be used to upward-continue the regional terrestrial data to the flight level of the airborne survey, such that the terrestrial gravimetry outside the survey area can be merged with the airborne data inside the survey area, all at flight level. Harmonic analysis of this merged data set, also at flight level, yields a second ‘airborne-augmented' expansion, which closely matches the ‘terrestrial-only' expansion outside the survey area, but which also closely reproduces the airborne survey data inside the survey area. Capturing the airborne and terrestrial data in this way means that downward-continuation of the airborne data, as well as spectral/spatial comparison (and ultimate combination) of the airborne data with the terrestrial (and satellite) data, can all be achieved through spherical- and ellipsoidal-harmonic synthesis of these two competing expansions, and their spectral combination. This general approach is illustrated with a worked example.

  11. Gravity and magnetic survey of the Oaxaca city region: Cenozoic horst-and-graben structure superimposed on the Oaxaca-Juarez terrane boundary, southern Mexico

    NASA Astrophysics Data System (ADS)

    Campos-Enríquez, J. O.; Belmonte-Jiménez, S. I.; Keppie, J. D.; Ortega-Gutiérrez, F.; Arzate, J. A.; Martínez-Silva, J.; Martínez-Serrano, R. G.

    2010-04-01

    A geophysical survey of the Oaxaca Fault along the north-trending Etla and Zaachila valleys area, southern Mexico, shows a series of NNW-SSE Bouguer and magnetic anomalies with steeper gradients towards the east. The Oaxaca Fault represents Tertiary extensional reactivation of the Juarez shear zone that constitutes the boundary between the Oaxaca and Juárez terranes. Cooperative interpretation of six combined gravity and magnetic NE-SW profiles perpendicular to the valleys indicates the presence of a composite depression comprising three N-S sub-basins: the northern Etla and southern Zaachila sub-basins separated by the Atzompa sub-basin. The Etla sub-basin is bounded by the moderately E-dipping, Etla Fault and the more steeply W-dipping Oaxaca Fault, which together constitute a graben that continues southwards into the Atzompa graben. The deeper Zaachila sub-basin, south of Oaxaca city, is a wide V-shaped graben with a horst in the middle. The new geophysical data suggest that the Oaxaca-Juarez terrane boundary is displaced sinistrally ca. 20 km along the E-W Donají Fault, which defines the northern boundary of the Zaachila sub-basin. On the other hand, the Oaxaca Fault may either continue unbroken southwards along the western margin of the horst in the Zaachila sub-basin or be offset along with the terrane boundary. The sinistral movement may have taken place either during the Late Mesozoic-Early Cenozoic, Laramide Orogeny as a lateral ramp in the thrust plane or under Miocene-Pliocene, NE-SW extension. The former suggests that the Donají Fault is a transcurrent fault, whereas the latter implies that it is a transfer fault. The models imply that originally the suture was continuous south of the Donaji Fault and provide a constraint for the accretion of the Oaxaca and Juarez terranes.

  12. Terrain Corrections for Gravity Gradiometry

    NASA Astrophysics Data System (ADS)

    Huang, Ou

    This study developed a geostatistical method to determine the required extent of terrain corrections for gravity gradients under the criterion of different applications. We present the different methods to compute the terrain corrections for gravity gradients for the case of ground and airborne gravity gradiometry. In order to verify our geostatistical method and study the required extent for different types of terrain, we also developed a method to simulate topography based on the covariance model. The required extents were determined from the variance of truncation error for one point, or furthermore from the variance of truncation error difference for a pair of points, and these variances were verified with that from the deterministic method. The extent of terrain correction was determined for ground gradiometry based on simulated, ultra-high resolution topography for very local application, and also was determined based on mountainous topography of large areas. For airborne gradiometry, we compute the terrain corrections and the required extent based on Air-FTG observations at Vinton Dome, LA and Parkfield, CA area; also they were verified with the results of Bell Geospace. Finally, from the mostly flat, medium rough and mountainous areas, an empirical relationship was developed which has the properties that the required extent has 4 times relationship corresponding to the amplitude of PSD has 100 times relationship between mountainous and mostly flat areas, and it can be interpolated for other types of topography from their geostatistics.

  13. Compliance with Standard Guidelines for the Prevention of Occupational Transmission of Bloodborne and Airborne Pathogens: A Survey of Postanesthesia Nursing Practice.

    ERIC Educational Resources Information Center

    Tait, Alan R.; Voepel-Lewis, Terri; Tuttle, Dale B.; Malviya, Shobha

    2000-01-01

    A survey of 34 nurses found that 81% always complied with guidelines for caring for patients with human immunodeficiency virus or hepatitis B; only 31% complied when patients were low risk. Reasons for noncompliance were "no anticipated blood contact" (53%) or "too busy" (25%). (SK)

  14. Cosmological tests of modified gravity.

    PubMed

    Koyama, Kazuya

    2016-04-01

    We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard [Formula: see text]CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years. PMID:27007681

  15. Cosmological tests of modified gravity.

    PubMed

    Koyama, Kazuya

    2016-04-01

    We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard [Formula: see text]CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.

  16. Cosmological tests of modified gravity

    NASA Astrophysics Data System (ADS)

    Koyama, Kazuya

    2016-04-01

    We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein’s theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard Λ CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.

  17. Preliminary Gravity and Ground Magnetic Data in the Arbuckle Uplift near Sulphur, Oklahoma

    USGS Publications Warehouse

    Scheirer, Daniel S.; Aboud, Essam

    2008-01-01

    Improving knowledge of the geology and geophysics of the Arbuckle Uplift in south-central Oklahoma is a goal of the Framework Geology of Mid-Continent Carbonate Aquifers project sponsored by the United States Geological Survey (USGS) National Cooperative Geologic Mapping Program (NCGMP). In May 2007, we collected ground magnetic and gravity observations in the Hunton Anticline region of the Arbuckle Uplift, near Sulphur, Oklahoma. These observations complement prior gravity data collected for a project sponsored by the National Park Service and helicopter electromagnetic (HEM) and aeromagnetic data collected in March 2007 for the NCGMP project. This report describes the instrumentation and processing that was utilized in the May 2007 geophysical fieldwork, and it presents preliminary results as gravity anomaly maps and magnetic anomaly profiles. Digital tables of gravity and magnetic observations are provided as a supplement to this report. Future work will generate interpretive models of these anomalies and will involve joint analysis of these ground geophysical measurements with airborne and other geophysical and geological observations, with the goal of understanding the geological structures influencing the hydrologic properties of the Arbuckle-Simpson aquifer.

  18. Detection of groundwater conduits in limestones with gravity surveys: data from the area of the Chicxulub Impact crater, Yucatan Peninsula, Mexico

    NASA Technical Reports Server (NTRS)

    Kinsland, G. L.; Hurtado, M.; Pope, K. O.; Ocampo, A. C. (Principal Investigator)

    2000-01-01

    Small negative gravity anomalies are found in gravity data from along the northwestern shoreline of the Yucatan Peninsula. These anomalies are shown to be due to elongate, shallow anomalous porosity zones in the Tertiary carbonates. These zones are caused primarily by groundwater solution and are presently active conduits for groundwater flow. The association of these small gravity anomalies with known topographic and structural features of the area, which partially overlies the Chicxulub Impact crater, indicates their development was influenced by structures, faults and/or fractures, within the Tertiary and pre-Tertiary carbonates.

  19. Data reduction and tying in regional gravity surveys—results from a new gravity base station network and the Bouguer gravity anomaly map for northeastern Mexico

    NASA Astrophysics Data System (ADS)

    Hurtado-Cardador, Manuel; Urrutia-Fucugauchi, Jaime

    2006-12-01

    Since 1947 Petroleos Mexicanos (Pemex) has conducted oil exploration projects using potential field methods. Geophysical exploration companies under contracts with Pemex carried out gravity anomaly surveys that were referred to different floating data. Each survey comprises observations of gravity stations along highways, roads and trails at intervals of about 500 m. At present, 265 separate gravimeter surveys that cover 60% of the Mexican territory (mainly in the oil producing regions of Mexico) are available. This gravity database represents the largest, highest spatial resolution information, and consequently has been used in the geophysical data compilations for the Mexico and North America gravity anomaly maps. Regional integration of gravimeter surveys generates gradients and spurious anomalies in the Bouguer anomaly maps at the boundaries of the connected surveys due to the different gravity base stations utilized. The main objective of this study is to refer all gravimeter surveys from Pemex to a single new first-order gravity base station network, in order to eliminate problems of gradients and spurious anomalies. A second objective is to establish a network of permanent gravity base stations (BGP), referred to a single base from the World Gravity System. Four regional loops of BGP covering eight States of Mexico were established to support the tie of local gravity base stations from each of the gravimeter surveys located in the vicinity of these loops. The third objective is to add the gravity constants, measured and calculated, for each of the 265 gravimeter surveys to their corresponding files in the Pemex and Instituto Mexicano del Petroleo database. The gravity base used as the common datum is the station SILAG 9135-49 (Latin American System of Gravity) located in the National Observatory of Tacubaya in Mexico City. We present the results of the installation of a new gravity base network in northeastern Mexico, reference of the 43 gravimeter surveys

  20. High-precision gravity network to monitor temporal variations in gravity across Yucca Mountain, Nevada

    SciTech Connect

    Harris, R.N.; Ponce, D.A.

    1988-12-31

    Repeatable high-precision gravity surveys provide a method of monitoring temporal variations in the gravity field. Fluctuations in the gravity field may indicate water table changes, crustal deformation, or precursors to volcanism and earthquakes. This report describes a high-precision gravity loop which has been established across Yucca Mountain, Nevada in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) program. The purpose of this gravity loop is to monitor temporal variations in gravity across Yucca Mountain in an effort to interpret and predict the stability of the tectonic framework and changes in the subsurface density field. Studies of the tectonic framework which include volcanic hazard seismicity, and faulting studies are in progress. Repeat high-precision gravity surveys are less expensive and can be made more rapidly than a corresponding leveling survey. High-precision gravity surveys are capable of detecting elevation changes of 3 to 5 cm, and thus can be employed as an efficient tool for monitoring vertical crustal movements while supplementing or partially replacing leveling data. The Yucca Mountain gravity network has been tied to absolute gravity measurements established in southern Nevada. These ties provide an absolute datum for comparing repeat occupations of the gravity network, and provide a method of monitoring broad-scale changes in gravity. Absolute gravity measurements were also made at the bottom and top of the Charleston Peak calibration loop in southern Nevada. These absolute gravity measurements provide local control of calibrating gravity meters over the gravity ranges observed at Yucca Mountain. 13 refs., 7 figs., 3 tabs.

  1. Gravity's overdrive

    NASA Astrophysics Data System (ADS)

    Reichhardt, Tony

    1994-03-01

    Mariner 10 traveled to Mercury by using Venus' gravity to bend its course in toward the sun, a correction that would otherwise required vast amounts of rocket fuel. For the first time, an interplanetary spacecraft changed course not with rocket fuel but by using a planet's gravitational field. That maneuver stands, along with the development of the rocket engine, as one of the keys that opened the solar system for exploration. The Pioneer, Voyager, and Galileo missions all used gravity assist, and in fact would not have been possible otherwise. Gravity assist is the most efficient form of space propulsion known. Various aspects of the developmental history of the gravity assist technique and the dispute over who should receive credit for inventing the technique are discussed.

  2. Gravity brake

    DOEpatents

    Lujan, Richard E.

    2001-01-01

    A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.

  3. Gravity waves

    NASA Technical Reports Server (NTRS)

    Fritts, David

    1987-01-01

    Gravity waves contributed to the establishment of the thermal structure, small scale (80 to 100 km) fluctuations in velocity (50 to 80 m/sec) and density (20 to 30%, 0 to peak). Dominant gravity wave spectrum in the middle atmosphere: x-scale, less than 100 km; z-scale, greater than 10 km; t-scale, less than 2 hr. Theorists are beginning to understand middle atmosphere motions. There are two classes: Planetary waves and equatorial motions, gravity waves and tidal motions. The former give rise to variability at large scales, which may alter apparent mean structure. Effects include density and velocity fluctuations, induced mean motions, and stratospheric warmings which lead to the breakup of the polar vortex and cooling of the mesosphere. On this scale are also equatorial quasi-biennial and semi-annual oscillations. Gravity wave and tidal motions produce large rms fluctuations in density and velocity. The magnitude of the density fluctuations compared to the mean density is of the order of the vertical wavelength, which grows with height. Relative density fluctuations are less than, or of the order of 30% below the mesopause. Such motions may cause significant and variable convection, and wind shear. There is a strong seasonal variation in gravity wave amplitude. Additional observations are needed to address and quantify mean and fluctuation statistics of both density and mean velocity, variability of the mean and fluctuations, and to identify dominant gravity wave scales and sources as well as causes of variability, both temporal and geographic.

  4. Airborne gamma radiation soil moisture measurements over short flight lines

    NASA Technical Reports Server (NTRS)

    Peck, Eugene L.; Carrol, Thomas R.; Lipinski, Daniel M.

    1990-01-01

    Results are presented on airborne gamma radiation measurements of soil moisture condition, carried out along short flight lines as part of the First International Satellite Land Surface Climatology Project Field Experiment (FIFE). Data were collected over an area in Kansas during the summers of 1987 and 1989. The airborne surveys, together with ground measurements, provide the most comprehensive set of airborne and ground truth data available in the U.S. for calibrating and evaluating airborne gamma flight lines. Analysis showed that, using standard National Weather Service weights for the K, Tl, and Gc radiation windows, the airborne soil moisture estimates for the FIFE lines had a root mean square error of no greater than 3.0 percent soil moisture. The soil moisture estimates for sections having acquisition time of at least 15 sec were found to be reliable.

  5. Mars Airborne Prospecting Spectrometer

    NASA Astrophysics Data System (ADS)

    Steinkraus, J. M.; Wright, M. W.; Rheingans, B. E.; Steinkraus, D. E.; George, W. P.; Aljabri, A.; Hall, J. L.; Scott, D. C.

    2012-06-01

    One novel approach towards addressing the need for innovative instrumentation and investigation approaches is the integration of a suite of four spectrometer systems to form the Mars Airborne Prospecting Spectrometers (MAPS) for prospecting on Mars.

  6. Airborne gamma-ray spectrometer and magnetometer survey. Volume I. Detail areas. Final report. Christmas Mountains, Solitario, Green Valley/O-2 Ranch, Texas

    SciTech Connect

    Not Available

    1982-01-01

    Data were collected by a helicopter equipped with a gamma-ray spectrometer with a large crystal volume, and with a high sensitivity proton precession magnetometer. The radiometric system was calibrated at the Walker Field Calibration pads and the Lake Mead Dynamic Test Range. Data quality was ensured during the survey by daily test flights and equipment checks. Radiometric data were corrected for live time, aircraft and equipment background, cosmic background, atmospheric radon, Compton scatter, and altitude dependence. The corrected data were statistically evaluated, gridded, and contoured to produce maps of the radiometric variables, uranium, potassium, and thorium; their ratios; and the residual magnetic field. These maps have been analyzed in order to produce a multi-variant analysis contour map based on the radiometric response of the individual geological units. A geochemical analysis has been performed; using the radiometric and magnetic contour maps, the multi-variant analysis map, and factor analysis techniques; to produce a geochemical analysis map for the area. Volume I contains a description of the systems used in the survey, a discussion of the calibration of the systems, the data collection procedures, the data processing procedures, the data presentation, the interpretation rationale, and the interpretation methodology. Separate Volumes II-A and II-B for each detail area contain the data displays and the interpretation results.

  7. Airborne electromagnetics (EM) as a three-dimensional aquifer-mapping tool

    USGS Publications Warehouse

    Wynn, Jeff; Pool, Don; Bultman, Mark; Gettings, Mark; Lemieux, Jean

    2000-01-01

    The San Pedro River in southeastern Arizona hosts a major migratory bird flyway, and was declared a Riparian Conservation Area by Congress in 1988. Recharge of the adjacent Upper San Pedro Valley aquifer was thought to come primarily from the Huachuca Mountains, but the U. S. Army Garrison of Fort Huachuca and neighboring city of Sierra Vista have been tapping this aquifer for many decades, giving rise to claims that they jointly threatened the integrity of the Riparian Conservation Area. For this reason, the U. S. Army funded two airborne geophysical surveys over the Upper San Pedro Valley (see figure 1), and these have provided us valuable information on the aquifer and the complex basement structure underlying the modern San Pedro Valley. Euler deconvolution performed on the airborne magnetic data has provided a depth-to-basement map that is substantially more complex than a map obtained earlier from gravity data, as would be expected from the higher-resolution magnetic data. However, we found the output of the Euler deconvolution to have "geologic noise" in certain areas, interpreted to be post-Basin-and-Range Tertiary volcanic flows in the sedimentary column above the basement but below the ground surface.

  8. BF gravity

    NASA Astrophysics Data System (ADS)

    Celada, Mariano; González, Diego; Montesinos, Merced

    2016-11-01

    BF gravity comprises all the formulations of gravity that are based on deformations of BF theory. Such deformations consist of either constraints or potential terms added to the topological BF action that turn some of the gauge degrees of freedom into physical ones, particularly giving rise to general relativity. The BF formulations have provided new and deep insights into many classical and quantum aspects of the gravitational field, setting the foundations for the approach to quantum gravity known as spinfoam models. In this review, we present a self-contained and unified treatment of the BF formulations of D-dimensional general relativity and other related models, focusing on the classical aspects of them and including some new results.

  9. Systematic Analysis of Resolution and Uncertainties in Gravity Interpretation of Bathymetry Beneath Floating Ice

    NASA Astrophysics Data System (ADS)

    Cochran, J. R.; Tinto, K. J.; Elieff, S. H.; Bell, R. E.

    2011-12-01

    Airborne geophysical surveys in West Antarctica and Greenland carried out during Operation IceBridge (OIB) utilized the Sander Geophysics AIRGrav gravimeter, which collects high quality data during low-altitude, draped flights. This data has been used to determine bathymetry beneath ice shelves and floating ice tongues (e.g., Tinto et al, 2010, Cochran et al, 2010). This paper systematically investigates uncertainties arising from survey, instrumental and geologic constraints in this type of study and the resulting resolution of the bathymetry model. Gravity line data is low-pass filtered with time-based filters to remove high frequency noise. The spatial filter length is dependent on aircraft speed. For parameters used in OIB (70-140 s filters and 270-290 knots), spatial filter half-wavelengths are ~5-10 km. The half-wavelength does not define a lower limit to the width of feature that can be detected, but shorter wavelength features may appear wider with a lower amplitude. Resolution can be improved either by using a shorter filter or by flying slower. Both involve tradeoffs; a shorter filter allows more noise and slower speeds result in less coverage. These filters are applied along tracks, rather than in a region surrounding a measurement. In areas of large gravity relief, tracks in different directions can sample a very different range of gravity values within the length of the filter. We show that this can lead to crossover mismatches of >5 mGal, complicating interpretation. For dense surveys, gridding the data and then sampling the grid at the measurement points can minimize this effect. Resolution is also affected by the elevation of survey flights. For a distributed mass, the gravity amplitude decreases with distance and short-wavelength components attenuate faster. This is not a serious issue for OIB, which flew draped flights <500 m above the ice surface, but is a serious factor for gravimeters that require a constant elevation above the highest

  10. User definition and mission requirements for unmanned airborne platforms, revised

    NASA Technical Reports Server (NTRS)

    Kuhner, M. B.; Mcdowell, J. R.

    1979-01-01

    The airborne measurement requirements of the scientific and applications experiment user community were assessed with respect to the suitability of proposed strawman airborne platforms. These platforms provide a spectrum of measurement capabilities supporting associated mission tradeoffs such as payload weight, operating altitude, range, duration, flight profile control, deployment flexibility, quick response, and recoverability. The results of the survey are used to examine whether the development of platforms is warranted and to determine platform system requirements as well as research and technology needs.

  11. An Assessment of Airborn Gravimetry Collected under the NGS GRAV-D Project

    NASA Astrophysics Data System (ADS)

    Holmes, S. A.

    2009-12-01

    In the United States, the National Geodetic Survey [NGS] holds the official charter to maintain the vertical datum for the USA and its territories. This includes the responsibility to maintain a current geoid model for transforming between orthometric (H) and geodetic (h) heights. The latest (2009) NGS geoid model incorporates the latest GRACE-based satellite-only geopotential solutions, very-high-resolution digital elevation models [DEMs] derived from the Shuttle Radar Topography Mission [SRTM], and other additional data and processing improvements. This recent geoid model also benefited greatly from the prior release of the National Geospatial-Intelligence Agency’s [NGA] Earth Gravitational Model 2008 [EGM2008], which served as a computational reference field for the new geoid, but was also particularly useful for identifying and removing corrupted data from the NGS gravimetry database. Looking forwards, NGS intends to increase its efforts to refine and improve its future national geoid models. To this end, their ambitious "Gravity for the Re-definition of the American Datum” [GRAV-D] project aims to update the NGS gravimetry holdings by flying new airborn gravity surveys over a large fraction of the USA and it territories. Concurrent efforts will focus on developing new processing techniques for optimally incorporating improved gravimetry into the final geoid solution. To this end, the GRAV-D team has already flown several surveys in the Gulf of Mexico, Puerto Rico, US Virgin Islands, and Alaska. Testing and analysis aimed at calibrating and validating the preliminary survey data is already underway. The latest assessment of these recent efforts, including the extent to which this new data can be expected to contribute to an improved gravimetric geoid model, is presented here.

  12. The gravity field in Taiwan Strait

    SciTech Connect

    Su Daquan; Chen Xue; Liu Zuhui )

    1990-06-01

    Gravity surveys have been carried out in the western part of Taiwan Strait by South China Sea Institute of Oceanology, Academia Sinica, from 1986 to 1989. More than 3,000 km of gravity profile data have been collected. The accuracy of the gravity is about {plus minus}2.5 mGal. Based on these data, gravity maps of Taiwan Strait (1:2,000,000) have been compiled, combined with the data from University of Tokyo, Lamont-Doherty geological observatory, and the USSR, which were collected from the east and southeast parts of Taiwan Strait. The interval of contour is 5 mGal. These maps cover part of East China Sea and South China Sea, where good gravity data have been gathered. Comparing the data from different sources in the same area, the authors think they are in very good agreement. These maps for the first time give detailed gravity information in the Taiwan Strait. It is very useful for the tectonic study and oil exploration in this area. The relationship between gravity anomalies and sedimentary basins has been studied in this area. Most of data show that the gravity low corresponds to the basin area and the gravity high is related to tectonic structure high. Xia-Peng depression, Wuqiuy depression, and Xinzhu depression, etc., show the gravity low. The relationship also can be seen in the gravity profiles clearly. The general tendency of gravity in the Taiwan Strait is that the gravity values gradually increase from the south part to the north part. It can be probably explained by deep geological structures. The relationship between gravity and geological structure units is also studied. They think the undulation of gravity anomalies is closely related to tectonic structures. Some main faults can be confirmed by the gravity maps.

  13. Three-Axis Superconducting Gravity Gradiometer

    NASA Technical Reports Server (NTRS)

    Paik, Ho Jung

    1987-01-01

    Gravity gradients measured even on accelerating platforms. Three-axis superconducting gravity gradiometer based on flux quantization and Meissner effect in superconductors and employs superconducting quantum interference device as amplifier. Incorporates several magnetically levitated proof masses. Gradiometer design integrates accelerometers for operation in differential mode. Principal use in commercial instruments for measurement of Earth-gravity gradients in geo-physical surveying and exploration for oil.

  14. Superconducting gravity gradiometer for sensitive gravity measurements. I. Theory

    SciTech Connect

    Chan, H.A.; Paik, H.J.

    1987-06-15

    Because of the equivalence principle, a global measurement is necessary to distinguish gravity from acceleration of the reference frame. A gravity gradiometer is therefore an essential instrument needed for precision tests of gravity laws and for applications in gravity survey and inertial navigation. Superconductivity and SQUID (superconducting quantum interference device) technology can be used to obtain a gravity gradiometer with very high sensitivity and stability. A superconducting gravity gradiometer has been developed for a null test of the gravitational inverse-square law and space-borne geodesy. Here we present a complete theoretical model of this instrument. Starting from dynamical equations for the device, we derive transfer functions, a common mode rejection characteristic, and an error model of the superconducting instrument. Since a gradiometer must detect a very weak differential gravity signal in the midst of large platform accelerations and other environmental disturbances, the scale factor and common mode rejection stability of the instrument are extremely important in addition to its immunity to temperature and electromagnetic fluctuations. We show how flux quantization, the Meissner effect, and properties of liquid helium can be utilized to meet these challenges.

  15. World Gravity Map: a set of global complete spherical Bouguer and isostatic anomaly maps and grids

    NASA Astrophysics Data System (ADS)

    Bonvalot, S.; Balmino, G.; Briais, A.; Kuhn, M.; Peyrefitte, A.; Vales, N.; Biancale, R.; Gabalda, G.; Reinquin, F.

    2012-04-01

    Intelligence Agency (NGA) (Pavlis et al., 2008) and the DTU10 (Andersen, 2010) who represents the best up-to-date global gravity models (including surface gravity measurements from land, marine and airborne surveys as well as gravity and altimetry satellite measurements). The surface free-air anomaly is computed at the Earth's surface in the context of Molodensky theory and includes corrections from the mass of the atmosphere. The way gravity anomalies are computed on a worldwide basis slightly differs from the classical usage, but meets modern concerns which tend to take into account of the real Earth. The resulting anomaly maps and grids will be distributed for scientific and education purposes by the Commission for the Geological Map of the World (CGMW) (http://ccgm.free.fr) and by the Bureau Gravimetrique International (BGI) (http://bgi.omp.obs-mip.fr). Upgraded versions might be done as soon as new global gravity model will be available (including satellite GOCE data for instance). Institutions who are interested to contribute with new datasets of surface gravity measurements (i.e. ground, marine or airborne gravity data) are also invited to contact BGI bgi@cnes.fr.

  16. Gravity settling

    DOEpatents

    Davis, Hyman R.; Long, R. H.; Simone, A. A.

    1979-01-01

    Solids are separated from a liquid in a gravity settler provided with inclined solid intercepting surfaces to intercept the solid settling path to coalesce the solids and increase the settling rate. The intercepting surfaces are inverted V-shaped plates, each formed from first and second downwardly inclined upwardly curved intersecting conical sections having their apices at the vessel wall.

  17. Simulating Gravity

    ERIC Educational Resources Information Center

    Pipinos, Savas

    2010-01-01

    This article describes one classroom activity in which the author simulates the Newtonian gravity, and employs the Euclidean Geometry with the use of new technologies (NT). The prerequisites for this activity were some knowledge of the formulae for a particle free fall in Physics and most certainly, a good understanding of the notion of similarity…

  18. Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal

    2009-11-01

    The continuing search for quantum gravity and never ending attempts to unify gravity with other forces of nature represent tremendous waste of public and private funds directing students' energy towards non-creative manipulative work instead of learning from the scientific creativity in Einstein's 1919 paper that unifies gravity with nuclear force. It reflects Einstein's 1919 jump beyond his own 1915 theory of gravity, including that of Newton as implicitly demanded by Newton in 1686. Einstein corrected and retracted his 1917 introduction of cosmological constant in 1919. Dislike of the fact that Einstein did not use quantum mechanics to prove his point has no real value now, because we will use key ingredients (Planck scale and probabilistic aspect) of quantum mechanics and show that they reach the same conclusion. Newton explained the solar system known after Kepler. Likewise, our quantum mechanical approach explains the strong coupling as well the solar system and shows new horizons, otherwise unexplained. Explanation of unexplained observations need no prediction per Hawking, and obviously otherwise.

  19. Limitations on the resolution and suitability of global gravity and magnetic models for geological interpretation: A user health warning!

    NASA Astrophysics Data System (ADS)

    Fairhead, J. D.; Somerton, I. W.

    2011-12-01

    There have been major advances in the generation of global gravity and crustal magnetic models that are now down loadable from the Internet. All models have variable spatial resolution which is not always readily apparent when viewing these models. The global models include: 1) Free air gravity: EGM08 (5'), Danish DTU(1') and Sandwell and Smith V16.1 (1'). 2) TMI crustal magnetic: WDMAM (3') and EMAG3 (3'), where grid cell size is in arc minutes, where 1'≈ 2 km Both models can be spectrally divided into Long wavelength components: that are very well constrained and are derived from satellite observations. For Free air gravity: wavelengths > 150 km from Grace and for TMI crustal magnetic:wavlengths > 400 km from CHAMP MF6 Shorter wavelength components: The spatial resolution is very dependent on the data coverage of the terrestrial (ground, ship and airborne) surveys and are discussed below Gravity Model: The gravity model is expressed as the Free air gravity anomaly. For marine and large inland water areas the data used are derived from satellite altimeter measurements that generate a spatial gravity resolution of 15 to 20 km (full wavelength) from 3 to 4 km spaced orbital track data. For onshore areas the data coverage is highly variable from no data (e.g. interior Angola) to more than adequate coverage (e.g. Europe). To infill data gaps, free air correction values derived from the SRTM topography data were used. This results in a free air anomaly grid that appears to have full spectral content down to the resolution of the model. Locating where the data gaps exist is difficult, since the land gravity survey coverage for EGM08, used by all models, has not been released. A further resolution problem is that many large surveys used in EGM08 have been decimated to preserve their commercial value (e.g. GETECH input grids were decimated to at least 15' grid). TMI Crustal Magnetic Model: For marine areas these models suffer even larger problems in that the sparsity of

  20. Massive gravity

    NASA Astrophysics Data System (ADS)

    Mukohyama, Shinji

    2013-09-01

    The concept of mass has been central in many areas of physics. Gravitation is not an exception, and it has been one of the long-standing questions whether the graviton, a spin-2 particle that mediates gravity, can have a non-vanishing mass or not. This question is relevant from not only theoretical but also phenomenological viewpoints, since a nonzero graviton mass may lead to late-time acceleration of the universe and thus may be considered as an alternative to dark energy. In 2010, de Rham, Gabadadze and Tolley proposed the first example of a fully nonlinear massive gravity theory and showed that the so called Boulware-Deser ghost, which had been one of the major obstacles against a stable nonlinear theory of massive gravity since 1972, can be removed by construction. Since then, nonlinear massive gravity has been attracting significant interest among physicists and cosmologists. The nonlinear theory of massive gravity provides a theoretical framework in which properties of the remaining five physical degrees of freedom of massive gravity can be studied. As always with any low-energy effective theories, one of the first tasks would be to identify good and bad backgrounds. Depending on the choice of backgrounds, some of the five degrees of freedom may become strongly coupled, may exhibit instantaneous propagation, or may lead to ghost/gradient instabilities. A related subject is to seek interesting solutions such as those relevant for astrophysical objects and those describing self-accelerating cosmology. Those solutions will allow us to study phenomenological and cosmological implications of the theory. Yet another important task would be to seek a possible (partial) UV completion that can be applied beyond the regime of validity of the low-energy effective theory that we currently know of. We invited articles to cover those important subjects in massive gravity. Given the recent rapid developments in the field, however, it must be noted that this focus issue

  1. Close-range airborne photogrammetry: an effective tool for high-resolution sandy beach morphometric surveys. Examples from embayed beaches in French Guyana.

    NASA Astrophysics Data System (ADS)

    Brunier, Guillaume; Fleury, Jules; Anthony, Edward; Gardel, Antoine; Dussouillez, Philippe

    2015-04-01

    have a mean vertical accuracy less than +/- 5 cm compared to the GPS control points, with a maximum of 20 cm in marginal sectors near vegetation and in the swash zone in low-water conditions. To our knowledge, this is the first time a poorly textured surface composed of sand is reconstructed by photogrammetry, contrast in the studied object being necessary for this method. Our highly accurate photo resolution and pre-processing permitted imaging enough texture to proceed. Morphological features in the upper surf zone such as rip channels, and subaerial features, such as erosion scarps and aeolian forms, clearly appear. The comparison between the DSM validates the estimation of sediment transfers and the rotation process on this beach, unlike traditional beach monitoring with GPS, which involves large uncertainty linked to sparse point acquisition. It can be claimed that photogrammetry is low-cost, user-friendly, and offers new perspectives for non-specialist users in geomorphology and other fields recquiring high-resolution topographic data. It combines the advantages of the reproducibility of GPS topographic surveys and the high density and accuracy of LIDAR, but at very advantageous cost compared to the latter.

  2. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Specifications and preliminary design of an Airborne Oceanographic Lidar (AOL) system, which is to be constructed for installation and used on a NASA Wallops Flight Center (WFC) C-54 research aircraft, are reported. The AOL system is to provide an airborne facility for use by various government agencies to demonstrate the utility and practicality of hardware of this type in the wide area collection of oceanographic data on an operational basis. System measurement and performance requirements are presented, followed by a description of the conceptual system approach and the considerations attendant to its development. System performance calculations are addressed, and the system specifications and preliminary design are presented and discussed.

  3. Airborne rain mapping radar

    NASA Technical Reports Server (NTRS)

    Wilson, W. J.; Parks, G. S.; Li, F. K.; Im, K. E.; Howard, R. J.

    1988-01-01

    An airborne scanning radar system for remote rain mapping is described. The airborne rain mapping radar is composed of two radar frequency channels at 13.8 and 24.1 GHz. The radar is proposed to scan its antenna beam over + or - 20 deg from the antenna boresight; have a swath width of 7 km; a horizontal spatial resolution at nadir of about 500 m; and a range resolution of 120 m. The radar is designed to be applicable for retrieving rainfall rates from 0.1-60 mm/hr at the earth's surface, and for measuring linear polarization signatures and raindrop's fall velocity.

  4. NASA Airborne Lidar July 1991

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar July 1991 Data from the 1991 NASA Langley Airborne Lidar flights following the eruption of Pinatubo in July ... and Osborn [1992a, 1992b]. Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  5. NASA Airborne Lidar May 1992

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar May 1992 An airborne Nd:YAG (532 nm) lidar was operated by the NASA Langley Research Center about a year following the June 1991 eruption of ... Osborn [1992a, 1992b].  Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  6. Gravity survey and interpretation of Fort Irwin and vicinity, Mojave Desert, California: Chapter H in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California

    USGS Publications Warehouse

    Jachens, Robert C.; Langenheim, V.E.; Buesch, David C.

    2014-01-01

    In support of a hydrogeologic study of the groundwater resources on Fort Irwin, we have combined new gravity data with preexisting measurements to produce an isostatic residual gravity map, which we then separated into two components reflecting (1) the density distribution in the pre-Cenozoic basement complex and (2) the distribution of low-density Cenozoic volcanic and sedimentary deposits that lie on top of the basement complex. The second component was inverted to estimate the three-dimensional distribution of Cenozoic deposits by using constraints from geology, drillholes, and time-domain electromagnetic soundings. In most of the base, the Cenozoic deposits are no more than 300 m thick, except in the basins with more than 500 m of fill beneath Coyote Lake, Red Pass Lake, west of Nelson Lake, west of Superior Lake, Bicycle Lake, and in the vicinity of Nelson Lake.

  7. Expanding Gravity

    NASA Astrophysics Data System (ADS)

    Aisenberg, Sol

    2005-04-01

    Newton's gravitational constant Gn and Laws of Gravity are based upon observations in our solar system. Mysteries appear when they are used far outside our solar system Apparently, Newton's gravitational constant can not be applied at large distances. Dark matter was needed to explain the observed flat rotational velocity curves of spiral galaxies (Rubin), and of groups of remote galaxies (Zwicky). Our expansion of Newton's gravitational constant Gn as a power series in distance r, is sufficient to explain these observations without using dark matter. This is different from the MOND theory of Milgrom involving acceleration. Also, our Expanded Gravitational Constant (EGC) can show the correct use of the red shift. In addition to the Doppler contribution, there are three other contributions and these depend only upon gravity. Thus, velocity observations only based on the red shift can not be used to support the concept of the expanding universe, the accelerating expansion, or dark energy. Our expanded gravity constant can predict and explain Olbers' paradox (dark sky), and the temperature of the CMB (cosmic microwave background). Thus, CMB may not support the big bang and inflation.

  8. Is nonrelativistic gravity possible?

    SciTech Connect

    Kocharyan, A. A.

    2009-07-15

    We study nonrelativistic gravity using the Hamiltonian formalism. For the dynamics of general relativity (relativistic gravity) the formalism is well known and called the Arnowitt-Deser-Misner (ADM) formalism. We show that if the lapse function is constrained correctly, then nonrelativistic gravity is described by a consistent Hamiltonian system. Surprisingly, nonrelativistic gravity can have solutions identical to relativistic gravity ones. In particular, (anti-)de Sitter black holes of Einstein gravity and IR limit of Horava gravity are locally identical.

  9. Bed topography of Jakobshavn Isbræ, Greenland from high-resolution gravity data

    NASA Astrophysics Data System (ADS)

    An, L.; Rignot, E. J.; Morlighem, M.; Paden, J. D.; Holland, D. M.

    2015-12-01

    Jakobshavn Isbræ (JKS) is one of the largest marine terminating outlet glaciers in Greenland, feeding a fjord about 800 m deep in the west coast. JKS sped up more than twofold since 2002 and contributed nearly 1 mm of global sea level rise during the period from 2000 to 2011. Holland et al. (2008) posit that these changes coincided with a change in ocean conditions beneath the former ice tongue, yet little is known about the depth of the glacier at its grounding line and upstream of the grounding line and the sea floor depth of the fjord is not well known either. Here, we present a new approach to infer the glacier bed topography, ice thickness and sea floor bathymetry near the grounding line of JKS using high-resolution airborne gravity data from AirGRAV. AirGRAV data were collected in August 2012 from a helicopter platform. The data combined with radio echo sounding data, discrete point soundings in the fjord and the mass conservation approach on land ice. AirGRAV acquired a 500m spacing grid of free-air gravity data at 50 knots with sub-milligal accuracy, i.e. much higher than NASA Operation IceBridge (OIB)'s 5.2km resolution at 290 knots. We use a 3D inversion of the gravity data combining our observations and a forward modeling of the surrounding gravity field, and constrained at the boundary by radar echo soundings and point bathymetry. We reconstruct seamless bed topography at the grounding line that matches interior data and the sea floor bathymetry. The results reveal the true depth at the elbow of the terminal valley and the bed reversal in the proximity of the current grounding line. The analysis provides guidelines for future gravity survey of narrow fjords in terms of spatial resolution and gravity precision. The results also demonstrate the practicality of using high resolution gravity survey to resolve bed topography near glacier snouts, in places where radar sounding has been significantly challenged in the past. The inversion results are critical

  10. Airborne Fraunhofer Line Discriminator

    NASA Technical Reports Server (NTRS)

    Gabriel, F. C.; Markle, D. A.

    1969-01-01

    Airborne Fraunhofer Line Discriminator enables prospecting for fluorescent materials, hydrography with fluorescent dyes, and plant studies based on fluorescence of chlorophyll. Optical unit design is the coincidence of Fraunhofer lines in the solar spectrum occurring at the characteristic wavelengths of some fluorescent materials.

  11. Recognizing Airborne Hazards.

    ERIC Educational Resources Information Center

    Schneider, Christian M.

    1990-01-01

    The heating, ventilating, and air conditioning (HVAC) systems in older buildings often do not adequately handle air-borne contaminants. Outlines a three-stage Indoor Air Quality (IAQ) assessment and describes a case in point at a Pittsburgh, Pennsylvania, school. (MLF)

  12. 43 CFR 3836.13 - What are geological, geochemical, or geophysical surveys?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... anomalous mineral values and quantities that may in turn identify mineral deposits. (c) Geophysical surveys... other things, magnetic and electromagnetic surveys, gravity surveys, seismic surveys, and...

  13. Photoreactivation in Airborne Mycobacterium parafortuitum

    PubMed Central

    Peccia, Jordan; Hernandez, Mark

    2001-01-01

    Photoreactivation was observed in airborne Mycobacterium parafortuitum exposed concurrently to UV radiation (254 nm) and visible light. Photoreactivation rates of airborne cells increased with increasing relative humidity (RH) and decreased with increasing UV dose. Under a constant UV dose with visible light absent, the UV inactivation rate of airborne M. parafortuitum cells decreased by a factor of 4 as RH increased from 40 to 95%; however, under identical conditions with visible light present, the UV inactivation rate of airborne cells decreased only by a factor of 2. When irradiated in the absence of visible light, cellular cyclobutane thymine dimer content of UV-irradiated airborne M. parafortuitum and Serratia marcescens increased in response to RH increases. Results suggest that, unlike in waterborne bacteria, cyclobutane thymine dimers are not the most significant form of UV-induced DNA damage incurred by airborne bacteria and that the distribution of DNA photoproducts incorporated into UV-irradiated airborne cells is a function of RH. PMID:11526027

  14. A new degree-2190 (10 km resolution) gravity field model for Antarctica developed from GRACE, GOCE and Bedmap2 data

    NASA Astrophysics Data System (ADS)

    Hirt, Christian; Rexer, Moritz; Scheinert, Mirko; Pail, Roland; Claessens, Sten; Holmes, Simon

    2016-02-01

    The current high-degree global geopotential models EGM2008 and EIGEN-6C4 resolve gravity field structures to ˜ 10 km spatial scales over most parts of the of Earth's surface. However, a notable exception is continental Antarctica, where the gravity information in these and other recent models is based on satellite gravimetry observations only, and thus limited to about ˜ 80-120 km spatial scales. Here, we present a new degree-2190 global gravity model (GGM) that for the first time improves the spatial resolution of the gravity field over the whole of continental Antarctica to ˜ 10 km spatial scales. The new model called SatGravRET2014 is a combination of recent Gravity Recovery and Climate Experiment (GRACE) and Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite gravimetry with gravitational signals derived from the 2013 Bedmap2 topography/ice thickness/bedrock model with gravity forward modelling in ellipsoidal approximation. Bedmap2 is a significantly improved description of the topographic mass distribution over the Antarctic region based on a multitude of topographic surveys, and a well-suited source for modelling short-scale gravity signals as we show in our study. We describe the development of SatGravRET2014 which entirely relies on spherical harmonic modelling techniques. Details are provided on the least-squares combination procedures and on the conversion of topography to implied gravitational potential. The main outcome of our work is the SatGravRET2014 spherical harmonic series expansion to degree 2190, and derived high-resolution grids of 3D-synthesized gravity and quasigeoid effects over the whole of Antarctica. For validation, six data sets from the IAG Subcommission 2.4f "Gravity and Geoid in Antarctica" (AntGG) database were used comprising a total of 1,092,981 airborne gravimetric observations. All subsets consistently show that the Bedmap2-based short-scale gravity modelling improves the agreement over satellite

  15. Redetermination of the precise gravity fields around the Japanese Antarctic Station, Syowa, and evaluation of GOCE EGMs

    NASA Astrophysics Data System (ADS)

    Fukuda, Y.; Nogi, Y.; Matsuzaki, K.

    2014-12-01

    We have been conducting the precise gravity field determination around the Japanese Antarctic Station, Syowa in Lützow-Holm Bay, East Antarctica. So far, we employed GOCE (Gravity field and steady-state Ocean Circulation Explorer) RL-4 and earlier versions of the EGMs and the in-situ gravity data obtained by the Japanese Antarctic Research Expedition (JARE), i.e., land gravity data since 1967, surface ship data since 1985 and airborne gravity data in 2006. Using these data sets, we calculated the precise gravity fields by means of Least Squares Colocations (LSC) and evaluated the GOCE EGMs by comparing with the in-situ gravity data. Recently, new GOCE EGMs, TIM RL-5 and DIR RL-5 have been released. In addition, JARE ship borne gravity data have been reprocessed following a more unified procedure and some land gravity data have been added. Accordingly, we have recalculated the gravity fields using all the data combined. Practically, using those data sets, we estimated gravity anomalies and geoid heights in the area of 60-80S and 20-60E by means of LSC using a GOCE EGM as the long wave-length gravity fields and an empirical covariance function estimated from the airborne gravity data. In this procedure as well as using the obtained gravity field data, we also evaluated GOCE EGMs and other recent EGMs.

  16. Airborne investigation of bathymetric sills in Godthåbsfjord, Greenland - results from IcePOD and Operation IceBridge

    NASA Astrophysics Data System (ADS)

    Tinto, K. J.; Zappa, C. J.; Bell, R. E.; Frearson, N.; Cochran, J. R.; Boghosian, A.; Porter, D. F.

    2013-12-01

    The bathymetry of Greenlandic fjords is an important boundary condition for understanding circulation within the fjord. This in turn is crucial to the understanding of ocean-ice interactions at the margins of the Greenland ice sheet. Marine-based surveys have identified sills at the heads of many of these fjords, and demonstrated their importance to the circulation patterns within the fjords themselves. The inaccessibility of much of the Greenland fjord system leaves many regions poorly surveyed, with important data gaps remaining in the interior of the fjords. Airborne surveys provide a valuable platform for the study of fjord dynamics by offering wide coverage and the ability to survey otherwise inaccessible regions of fjords. In this study we combine results from Operation IceBridge gravity surveys with visible and infrared imagery from the IcePOD project to investigate circulation, transport, and mixing in Godthåbsfjord, Greenland, at the calving front of Kangiata Nunâta Sermia. The bathymetry of this fjord has been well mapped, but information is sparse from the inner 13 km where the fjord is filled with icebergs. Gravity data show a 4 mGal positive anomaly 10 km from the calving front. Models constrained by the gravity anomaly over a known sill further up the fjord give this newly identified sill a predicted depth of approximately 100 m. IcePOD is a multi-instrument pod flown on an LC130 operated by the New York Air National Guard. During test flights in the summer of 2013 multiple passes were made of the inner, iceberg-filled part of Godthåbsfjord with both visible and infra-red cameras. Here we compare the movement of ice within the fjord with modelled bathymetry from IceBridge to investigate the circulation of the inner part of the fjord.

  17. [Air-borne disease].

    PubMed

    Lameiro Vilariño, Carmen; del Campo Pérez, Victor M; Alonso Bürger, Susana; Felpeto Nodar, Irene; Guimarey Pérez, Rosa; Pérez Alvarellos, Alberto

    2003-11-01

    Respiratory protection is a factor which worries nursing professionals who take care of patients susceptible of transmitting microorganisms through the air more as every day passes. This type of protection covers the use of surgical or hygienic masks against the transmission of infection by airborne drops to the use of highly effective masks or respirators against the transmission of airborne diseases such as tuberculosis or SARS, a recently discovered disease. The adequate choice of this protective device and its correct use are fundamental in order to have an effective protection for exposed personnel. The authors summarize the main protective respiratory devices used by health workers, their characteristics and degree of effectiveness, as well as the circumstances under which each device is indicated for use. PMID:14705591

  18. MLS airborne antenna research

    NASA Technical Reports Server (NTRS)

    Yu, C. L.; Burnside, W. D.

    1975-01-01

    The geometrical theory of diffraction was used to analyze the elevation plane pattern of on-aircraft antennas. The radiation patterns for basic elements (infinitesimal dipole, circumferential and axial slot) mounted on fuselage of various aircrafts with or without radome included were calculated and compared well with experimental results. Error phase plots were also presented. The effects of radiation patterns and error phase plots on the polarization selection for the MLS airborne antenna are discussed.

  19. Airborne gravimetry, altimetry, and GPS navigation errors

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L.

    1992-01-01

    Proper interpretation of airborne gravimetry and altimetry requires good knowledge of aircraft trajectory. Recent advances in precise navigation with differential GPS have made it possible to measure gravity from the air with accuracies of a few milligals, and to obtain altimeter profiles of terrain or sea surface correct to one decimeter. These developments are opening otherwise inaccessible regions to detailed geophysical mapping. Navigation with GPS presents some problems that grow worse with increasing distance from a fixed receiver: the effect of errors in tropospheric refraction correction, GPS ephemerides, and the coordinates of the fixed receivers. Ionospheric refraction and orbit error complicate ambiguity resolution. Optimal navigation should treat all error sources as unknowns, together with the instantaneous vehicle position. To do so, fast and reliable numerical techniques are needed: efficient and stable Kalman filter-smoother algorithms, together with data compression and, sometimes, the use of simplified dynamics.

  20. Mutagenicity of airborne particles.

    PubMed

    Chrisp, C E; Fisher, G L

    1980-09-01

    The physical and chemical properties of airborne particles are important for the interpretation of their potential biologic significance as genotoxic hazards. For polydisperse particle size distributions, the smallest, most respirable particles are generally the most mutagenic. Particulate collection for testing purposes should be designed to reduce artifact formation and allow condensation of mutagenic compounds. Other critical factors such as UV irradiation, wind direction, chemical reactivity, humidity, sample storage, and temperature of combustion are important. Application of chemical extraction methods and subsequent class fractionation techniques influence the observed mutagenic activity. Particles from urban air, coal fly ash, automobile and diesel exhaust, agricultural burning and welding fumes contain primarily direct-acting mutagens. Cigarette smoke condensate, smoke from charred meat and protein pyrolysates, kerosene soot and cigarette smoke condensates contain primarily mutagens which require metabolic activation. Fractionation coupled with mutagenicity testing indicates that the most potent mutagens are found in the acidic fractions of urban air, coal fly ash, and automobile diesel exhaust, whereas mutagens in rice straw smoke and cigarette smoke condensate are found primarily in the basic fractions. The interaction of the many chemical compounds in complex mixtures from airborne particles is likely to be important in determining mutagenic or comutagenic potentials. Because the mode of exposure is generally frequent and prolonged, the presence of tumor-promoting agents in complex mixtures may be a major factor in evaluation of the carcinogenic potential of airborne particles.

  1. Mammalian airborne allergens.

    PubMed

    Aalberse, Rob C

    2014-01-01

    Historically, horse dandruff was a favorite allergen source material. Today, however, allergic symptoms due to airborne mammalian allergens are mostly a result of indoor exposure, be it at home, at work or even at school. The relevance of mammalian allergens in relation to the allergenic activity of house dust extract is briefly discussed in the historical context of two other proposed sources of house dust allergenic activity: mites and Maillard-type lysine-sugar conjugates. Mammalian proteins involved in allergic reactions to airborne dust are largely found in only 2 protein families: lipocalins and secretoglobins (Fel d 1-like proteins), with a relatively minor contribution of serum albumins, cystatins and latherins. Both the lipocalin and the secretoglobin family are very complex. In some instances this results in a blurred separation between important and less important allergenic family members. The past 50 years have provided us with much detailed information on the genomic organization and protein structure of many of these allergens. However, the complex family relations, combined with the wide range of post-translational enzymatic and non-enzymatic modifications, make a proper qualitative and quantitative description of the important mammalian indoor airborne allergens still a significant proteomic challenge. PMID:24925404

  2. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  3. Airborne Bacterial Diversity from the Low Atmosphere of Greater Mexico City.

    PubMed

    García-Mena, Jaime; Murugesan, Selvasankar; Pérez-Muñoz, Ashael Alfredo; García-Espitia, Matilde; Maya, Otoniel; Jacinto-Montiel, Monserrat; Monsalvo-Ponce, Giselle; Piña-Escobedo, Alberto; Domínguez-Malfavón, Lilianha; Gómez-Ramírez, Marlenne; Cervantes-González, Elsa; Núñez-Cardona, María Teresa

    2016-07-01

    Greater Mexico City is one of the largest urban centers in the world, with an estimated population by 2010 of more than 20 million inhabitants. In urban areas like this, biological material is present at all atmospheric levels including live bacteria. We sampled the low atmosphere in several surveys at different points by the gravity method on LB and blood agar media during winter, spring, summer, and autumn seasons in the years 2008, 2010, 2011, and 2012. The colonial phenotype on blood agar showed α, β, and γ hemolytic activities among the live collected bacteria. Genomic DNA was extracted and convenient V3 hypervariable region libraries of 16S rDNA gene were high-throughput sequenced. From the data analysis, Firmicutes, Proteobacteria, and Actinobacteria were the more abundant phyla in all surveys, while the genera from the family Enterobacteriaceae, in addition to Bacillus spp., Pseudomonas spp., Acinetobacter spp., Erwinia spp., Gluconacetobacter spp., Proteus spp., Exiguobacterium spp., and Staphylococcus spp. were also abundant. From this study, we conclude that it is possible to detect live airborne nonspore-forming bacteria in the low atmosphere of GMC, associated to the microbial cloud of its inhabitants.

  4. Airborne Bacterial Diversity from the Low Atmosphere of Greater Mexico City.

    PubMed

    García-Mena, Jaime; Murugesan, Selvasankar; Pérez-Muñoz, Ashael Alfredo; García-Espitia, Matilde; Maya, Otoniel; Jacinto-Montiel, Monserrat; Monsalvo-Ponce, Giselle; Piña-Escobedo, Alberto; Domínguez-Malfavón, Lilianha; Gómez-Ramírez, Marlenne; Cervantes-González, Elsa; Núñez-Cardona, María Teresa

    2016-07-01

    Greater Mexico City is one of the largest urban centers in the world, with an estimated population by 2010 of more than 20 million inhabitants. In urban areas like this, biological material is present at all atmospheric levels including live bacteria. We sampled the low atmosphere in several surveys at different points by the gravity method on LB and blood agar media during winter, spring, summer, and autumn seasons in the years 2008, 2010, 2011, and 2012. The colonial phenotype on blood agar showed α, β, and γ hemolytic activities among the live collected bacteria. Genomic DNA was extracted and convenient V3 hypervariable region libraries of 16S rDNA gene were high-throughput sequenced. From the data analysis, Firmicutes, Proteobacteria, and Actinobacteria were the more abundant phyla in all surveys, while the genera from the family Enterobacteriaceae, in addition to Bacillus spp., Pseudomonas spp., Acinetobacter spp., Erwinia spp., Gluconacetobacter spp., Proteus spp., Exiguobacterium spp., and Staphylococcus spp. were also abundant. From this study, we conclude that it is possible to detect live airborne nonspore-forming bacteria in the low atmosphere of GMC, associated to the microbial cloud of its inhabitants. PMID:26944561

  5. Airborne gravimetry data sparse reconstruction via L1-norm convex quadratic programming

    NASA Astrophysics Data System (ADS)

    Yang, Ya-Peng; Wu, Mei-Ping; Tang, Gang

    2015-06-01

    In practice, airborne gravimetry is a sub-Nyquist sampling method because of the restrictions imposed by national boundaries, financial cost, and database size. In this study, we analyze the sparsity of airborne gravimetry data by using the discrete Fourier transform and propose a reconstruction method based on the theory of compressed sensing for large-scale gravity anomaly data. Consequently, the reconstruction of the gravity anomaly data is transformed to a L1-norm convex quadratic programming problem. We combine the preconditioned conjugate gradient algorithm (PCG) and the improved interior-point method (IPM) to solve the convex quadratic programming problem. Furthermore, a flight test was carried out with the homegrown strapdown airborne gravimeter SGA-WZ. Subsequently, we reconstructed the gravity anomaly data of the flight test, and then, we compared the proposed method with the linear interpolation method, which is commonly used in airborne gravimetry. The test results show that the PCG-IPM algorithm can be used to reconstruct large-scale gravity anomaly data with higher accuracy and more effectiveness than the linear interpolation method.

  6. Airborne Submillimeter Spectroscopy

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1998-01-01

    This is the final technical report for NASA-Ames grant NAG2-1068 to Caltech, entitled "Airborne Submillimeter Spectroscopy", which extended over the period May 1, 1996 through January 31, 1998. The grant was funded by the NASA airborne astronomy program, during a period of time after the Kuiper Airborne Observatory was no longer operational. Instead. this funding program was intended to help develop instrument concepts and technology for the upcoming SOFIA (Stratospheric Observatory for Infrared Astronomy) project. SOFIA, which is funded by NASA and is now being carried out by a consortium lead by USRA (Universities Space Research Association), will be a 747 aircraft carrying a 2.5 meter diameter telescope. The purpose of our grant was to fund the ongoing development of sensitive heterodyne receivers for the submillimeter band (500-1200 GHz), using sensitive superconducting (SIS) detectors. In 1997 July we submitted a proposal to USRA to construct a heterodyne instrument for SOFIA. Our proposal was successful [1], and we are now continuing our airborne astronomy effort with funding from USRA. A secondary purpose of the NAG2-1068 grant was to continue the anaIN'sis of astronomical data collected with an earlier instrument which was flown on the NASA Kuiper Airborne Observatory (KAO). The KAO instrument and the astronomical studies which were carried out with it were supported primarily under another grant, NAG2-744, which extended over October 1, 1991 through Januarv 31, 1997. For a complete description of the astronomical data and its anailysis, we refer the reader to the final technical report for NAG2-744, which was submitted to NASA on December 1. 1997. Here we report on the SIS detector development effort for SOFIA carried out under NAG2-1068. The main result of this effort has been the demonstration of SIS mixers using a new superconducting material niobium titanium nitride (NbTiN), which promises to deliver dramatic improvements in sensitivity in the 700

  7. Airborne Dust in Space Vehicles and Habitats

    NASA Technical Reports Server (NTRS)

    James, John

    2006-01-01

    Airborne dust, suspended inside a space vehicle or in future celestial habitats, can present a serious threat to crew health if it is not controlled. During the Apollo missions to the moon, lunar dust brought inside the capsule caused eye irritation and breathing difficulty to the crew when they launched from the moon and re-acquired "microgravity." During Shuttle flights reactive and toxic dusts such as lithium hydroxide have created a risk to crew health, and fine particles from combustion events can be especially worrisome. Under nominal spaceflight conditions, airborne dusts and particles tend to be larger than on earth because of the absence of gravity settling. Aboard the ISS, dusts are effectively managed by HEPA filters, although floating dust in newly-arrived modules can be a nuisance. Future missions to the moon and to Mars will present additional challenges because of the possibility that external dust will enter the breathing atmosphere of the habitat and reach the crew's respiratory system. Testing with simulated lunar and Martian dust has shown that these materials are toxic when placed into the lungs of test animals. Defining and evaluating the physical and chemical properties of Martian dusts through robotic missions will challenge our ability to prepare better dust simulants and to determine the risk to crew health from exposure to such dusts.

  8. Calibration Matters: Advances in Strapdown Airborne Gravimetry

    NASA Astrophysics Data System (ADS)

    Becker, D.

    2015-12-01

    Using a commercial navigation-grade strapdown inertial measurement unit (IMU) for airborne gravimetry can be advantageous in terms of cost, handling, and space consumption compared to the classical stable-platform spring gravimeters. Up to now, however, large sensor errors made it impossible to reach the mGal-level using such type IMUs as they are not designed or optimized for this kind of application. Apart from a proper error-modeling in the filtering process, specific calibration methods that are tailored to the application of aerogravity may help to bridge this gap and to improve their performance. Based on simulations, a quantitative analysis is presented on how much IMU sensor errors, as biases, scale factors, cross couplings, and thermal drifts distort the determination of gravity and the deflection of the vertical (DOV). Several lab and in-field calibration methods are briefly discussed, and calibration results are shown for an iMAR RQH unit. In particular, a thermal lab calibration of its QA2000 accelerometers greatly improved the long-term drift behavior. Latest results from four recent airborne gravimetry campaigns confirm the effectiveness of the calibrations applied, with cross-over accuracies reaching 1.0 mGal (0.6 mGal after cross-over adjustment) and DOV accuracies reaching 1.1 arc seconds after cross-over adjustment.

  9. Gravity data from the San Pedro River Basin, Cochise County, Arizona

    USGS Publications Warehouse

    Kennedy, Jeffrey R.; Winester, Daniel

    2011-01-01

    The U.S. Geological Survey, Arizona Water Science Center in cooperation with the National Oceanic and Atmospheric Administration, National Geodetic Survey has collected relative and absolute gravity data at 321 stations in the San Pedro River Basin of southeastern Arizona since 2000. Data are of three types: observed gravity values and associated free-air, simple Bouguer, and complete Bouguer anomaly values, useful for subsurface-density modeling; high-precision relative-gravity surveys repeated over time, useful for aquifer-storage-change monitoring; and absolute-gravity values, useful as base stations for relative-gravity surveys and for monitoring gravity change over time. The data are compiled, without interpretation, in three spreadsheet files. Gravity values, GPS locations, and driving directions for absolute-gravity base stations are presented as National Geodetic Survey site descriptions.

  10. Gravity survey and regional geology of the Prince William Sound epicentral region, Alaska: Chapter C in The Alaska earthquake, March 27, 1964: regional effects

    USGS Publications Warehouse

    Case, J.E.; Barnes, D.F.; Plafker, George; Robbins, S.L.

    1966-01-01

    Sedimentary and volcanic rocks of Mesozoic and early Tertiary age form a roughly arcuate pattern in and around Prince William Sound, the epicentral region of the Alaska earthquake of 1964. These rocks include the Valdez Group, a predominantly slate and graywacke sequence of Jurassic and Cretaceous age, and the Orca Group, a younger sequence of early Tertiary age. The Orca consists of a lower unit of dense-average 2.87 g per cm3 (grams per cubic centimeter) pillow basalt and greenstone intercalated with sedimentary rocks and an upper unit of lithologically variable sandstone interbedded with siltstone or argillite. Densities of the clastic rocks in both the Valdez and Orca Groups average about 2.69 g per cm3. Granitic rocks of relatively low density (2.62 g per cm3) cut the Valdez and Orca Groups at several localities. Both the Valdez and the Orca Groups were complexly folded and extensively faulted during at least three major episodes of deformation: an early period of Cretaceous or early Tertiary orogeny, a second orogeny that probably culminated in late Eocene or early Oligocene time and was accompanied or closely followed by emplacement of granitic batholiths, and a third episode of deformation that began in late Cenozoic time and continued intermittently to the present. About 500 gravity stations were established in the Prince William Sound region in conjunction with postearthquake geologic investigations. Simple Bouguer anomaly contours trend approximately parallel to the arcuate geologic structure around the sound. Bouguer anomalies decrease northward from +40 mgal (milligals) at the southwestern end of Montague Island to -70 mgal at College and Harriman Fiords. Most of this change may be interpreted as a regional gradient caused by thickening of the continental crust. Superimposed on the gradient is a prominent gravity high of as much as 65 mgal that extends from Elrington Island on the southwest, across Knight and Glacier Islands to the Ellamar Peninsula

  11. Artificial gravity.

    PubMed

    Scott, William B

    2005-04-25

    NASA's Artificial Gravity program consists of a team of researchers from Wyle Laboratories, NASA Johnson Space Center, and the University of Texas Medical Branch (UTMB). The short-radius centrifuge (SRC), built by Wyle Laboratories, will be integrated with UTMB's conducted bedrest studies, which mimic the detrimental effects of weightlessness (or microgravity). Bedrest subjects will be spun on the SRC at various accelerations and for various time periods, while being monitored medically. Parameters such as bone loss, muscle atrophy, balance control, and oxygen consumption will then be compared in order to research ways of mitigating the impact on astronauts' physiology. Other potential benefits from these studies extend to population groups on Earth, such as bedridden patients. PMID:15852559

  12. Airborne Electromagnetic Mapping of Subsurface Permafrost

    NASA Astrophysics Data System (ADS)

    Abraham, J. D.; Minsley, B. J.; Cannia, J. C.; Smith, B. D.; Walvoord, M. A.; Voss, C. I.; Jorgenson, T. T.; Wylie, B. K.; Anderson, L.

    2011-12-01

    Concerns over the impacts of climate change have recently energized research on the potential impacts thawing permafrost may have on groundwater flow, infrastructure, forest health, ecosystems, energy production, CO2 release, and contaminant transport. There is typically little knowledge about subsurface permafrost distributions, such as thickness and where groundwater-surface-water connections may occur through taliks. In June of 2010, the U.S. Geological Survey undertook an airborne electromagnetic (AEM) survey in the area of Fort Yukon, Alaska in order to map the 3-D distribution of permafrost and provide information for the development of groundwater models within the Yukon River Basin. Prior to the development of these models, information on areas of groundwater-surface water interaction was extremely limited. Lithology determined from a borehole drilled in Fort Yukon in 1994 agrees well with the resistivity depth sections inferred from the airborne survey. In addition to lithology, there a thermal imprint appears on the subsurface resistivity values. In the upper 20-50 m, the sections show continuous areas of high electrical resistivity, consistent with alluvial gravel deposits that are likely frozen. At depth, unfrozen gravel deposits have intermediate-to-high resistivity; frozen silts have intermediate resistivity; and unfrozen silts have low resistivity. Under the Yukon River and lakes where the subsurface is not frozen, zones of moderate resistivity intermix with areas of low resistivity. The areas of loess hills on the margins of the Yukon Flats have very-high electrical resistivity, indicating higher ice content, and are associated with the some of the greatest thickness of permafrost in the survey area. This work provides the first look into the 3-D distribution of permafrost in the areas around Fort Yukon and is a demonstration of the application of AEM to permafrost mapping. The AEM survey provides unprecedented 3-D images of subsurface electrical

  13. The fate of airborne polycyclic organic matter.

    PubMed Central

    Nielsen, T; Ramdahl, T; Bjørseth, A

    1983-01-01

    Biological tests have shown that a significant part of the mutagenicity of organic extracts of collected airborne particulate matter is not due to polycyclic aromatic hydrocarbons (PAH). It is possible that part of these unknown compounds are transformation products of PAH. This survey focuses on the reaction of PAH in the atmosphere with other copollutants, such as nitrogen oxides, sulfur oxides, ozone and free radicals and their reaction products. Photochemically induced reactions of PAH are also included. The reactivity of particle-associated PAH is discussed in relation to the chemical composition and the physical properties of the carrier. Recommendations for future work are given. PMID:6825615

  14. Airborne Oceanographic Lidar System

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The Airborne Oceanographic Lidar (AOL), a spatially scanning range-gated device installed on board a NASA C-54 aircraft, is described. The AOL system is capable of measuring topographical relief or water depth (bathymetry) with a range resolution of plus or minus 0.3 m in the vertical dimension. The system may also be used to measure fluorescent spectral signatures from 3500 to 8000 A with a resolution of 100 A. Potential applications of the AOL, including sea state measurements, water transparency assessments, oil spill identification, effluent identification and crop cover assessment are also mentioned.

  15. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown.

  16. Airborne ballistic camera tracking systems

    NASA Technical Reports Server (NTRS)

    Redish, W. L.

    1976-01-01

    An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

  17. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown. PMID:23406937

  18. Gravity Waves

    NASA Technical Reports Server (NTRS)

    Vanzandt, T. E.

    1985-01-01

    Atmospheric parameters fluctuate on all scales. In the mesoscale these fluctuations are occasionally sinusoidal so that they can be interpreted as gravity waves. Usually, however, the fluctuations are noise like, so that their cause is not immediately evident. Results of mesoscale observations in the 20 to 120 m altitude range that are suitable for incorporation into a model atmosphere are very limited. In the stratosphere and lower mesosphere observations are sparse and very little data has been summarized into appropriate form. There is much more data in the upper mesosphere and lower thermosphere, but again very little of it has been summarized. The available mesoscale spectra of horizontal wind u versus vertical wave number m in the 20 to 120 km altitude range are shown together with a spectrum from the lower atmosphere for comparison. Further information about these spectra is given. In spite of the large range of altitudes and latitudes, the spectra from the lower atmosphere (NASA, 1971 and DEWAN, 1984) are remarkably similar in both shape and amplitude. The mean slopes of -2.38 for the NASA spectrum and -2.7 for the Dewan spectra are supported by the mean slope of -2.75 found by ROSENBERG et al. (1974). The mesospheric spectrum is too short to establish a shape. Its amplitude is about an order of magnitude larger than the NASA spectrum in the same wave number range. The NASA and Dewan spectra suggest that the mesoscale spectra in the lower atmosphere are insensitive to meteorological conditions.

  19. Gravity wave transmission diagram

    NASA Astrophysics Data System (ADS)

    Tomikawa, Yoshihiro

    2016-07-01

    A possibility of gravity wave propagation from a source region to the airglow layer around the mesopause has been discussed based on the gravity wave blocking diagram taking into account the critical level filtering alone. This paper proposes a new gravity wave transmission diagram in which both the critical level filtering and turning level reflection of gravity waves are considered. It shows a significantly different distribution of gravity wave transmissivity from the blocking diagram.

  20. Detecting inertial effects with airborne matter-wave interferometry

    PubMed Central

    Geiger, R.; Ménoret, V.; Stern, G.; Zahzam, N.; Cheinet, P.; Battelier, B.; Villing, A.; Moron, F.; Lours, M.; Bidel, Y.; Bresson, A.; Landragin, A.; Bouyer, P.

    2011-01-01

    Inertial sensors relying on atom interferometry offer a breakthrough advance in a variety of applications, such as inertial navigation, gravimetry or ground- and space-based tests of fundamental physics. These instruments require a quiet environment to reach their performance and using them outside the laboratory remains a challenge. Here we report the first operation of an airborne matter-wave accelerometer set up aboard a 0g plane and operating during the standard gravity (1g) and microgravity (0g) phases of the flight. At 1g, the sensor can detect inertial effects more than 300 times weaker than the typical acceleration fluctuations of the aircraft. We describe the improvement of the interferometer sensitivity in 0g, which reaches 2 x 10-4 ms-2 / √Hz with our current setup. We finally discuss the extension of our method to airborne and spaceborne tests of the Universality of free fall with matter waves. PMID:21934658

  1. Detecting inertial effects with airborne matter-wave interferometry.

    PubMed

    Geiger, R; Ménoret, V; Stern, G; Zahzam, N; Cheinet, P; Battelier, B; Villing, A; Moron, F; Lours, M; Bidel, Y; Bresson, A; Landragin, A; Bouyer, P

    2011-09-20

    Inertial sensors relying on atom interferometry offer a breakthrough advance in a variety of applications, such as inertial navigation, gravimetry or ground- and space-based tests of fundamental physics. These instruments require a quiet environment to reach their performance and using them outside the laboratory remains a challenge. Here we report the first operation of an airborne matter-wave accelerometer set up aboard a 0g plane and operating during the standard gravity (1g) and microgravity (0g) phases of the flight. At 1g, the sensor can detect inertial effects more than 300 times weaker than the typical acceleration fluctuations of the aircraft. We describe the improvement of the interferometer sensitivity in 0g, which reaches 2 x 10-4 ms-2 / √Hz with our current setup. We finally discuss the extension of our method to airborne and spaceborne tests of the Universality of free fall with matter waves.

  2. Airborne bathymetric charting using pulsed blue-green lasers

    NASA Technical Reports Server (NTRS)

    Kim, H. H.

    1977-01-01

    Laboratory and airborne experiments have proven the feasibility and demonstrated the techniques of an airborne pulsed laser system for rapidly mapping coastal water bathymetry. Water depths of 10 plus or minus 0.25 m were recorded in waters having an effective attenuation coefficient of 0.175 m. A 2-MW peak power Nd:YAG pulsed laser was flown at an altitude of 600 m. An advanced system, incorporating a mirror scanner, a high pulsed rate laser, and a good signal processor, could survey coastal zones at the rate of several square miles per hour.

  3. Surface Gravity Data Contribution to the Puerto Rico and U.S. Virgin Islands Geoid Model

    NASA Astrophysics Data System (ADS)

    Li, X.; Gerhards, C.; Holmes, S. A.; Saleh, J.; Shaw, B.

    2015-12-01

    The Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project provides updated local gravity field information for the XGEOID15 models. In particular, its airborne gravity data in the area of Puerto Rico and U.S. Virgin Islands (PRVI) made substantial improvements (~60%) on the precision of the geoid models at the local GNSS/Leveling bench marks in the target area. Fortunately, PRVI is free of the huge systematic error in the North American Vertical Datum of 1988 (NAVD88). Thus, the airborne contribution was evaluated more realistically. In addition, the airborne data picked up more detailed gravity field information in the medium wavelength band (spherical harmonic degree 200 to 600) that are largely beyond the resolution of the current satellite missions, especially along the nearby ocean trench areas. Under this circumstance (significant airborne contributions in the medium band), local surface gravity data need to be examined more carefully than before during merging with the satellite and airborne information for local geoid improvement, especially considering the well-known systematic problems in the NGS historical gravity holdings (Saleh et al 2013 JoG). Initial tests showed that it is very important to maintain high consistency between the surface data sets and the airborne enhanced reference model. In addition, a new aggregation method (Gerhards 2014, Inverse Problems) will also be tested to optimally combine the local surface data with the reference model. The data cleaning and combining procedures in the target area will be summarized here as reference for future applications.

  4. Modeling for Airborne Contamination

    SciTech Connect

    F.R. Faillace; Y. Yuan

    2000-08-31

    The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of sufficient thickness to simulate the drift

  5. Chiral gravity, log gravity, and extremal CFT

    SciTech Connect

    Maloney, Alexander; Song Wei; Strominger, Andrew

    2010-03-15

    We show that the linearization of all exact solutions of classical chiral gravity around the AdS{sub 3} vacuum have positive energy. Nonchiral and negative-energy solutions of the linearized equations are infrared divergent at second order, and so are removed from the spectrum. In other words, chirality is confined and the equations of motion have linearization instabilities. We prove that the only stationary, axially symmetric solutions of chiral gravity are BTZ black holes, which have positive energy. It is further shown that classical log gravity--the theory with logarithmically relaxed boundary conditions--has finite asymptotic symmetry generators but is not chiral and hence may be dual at the quantum level to a logarithmic conformal field theories (CFT). Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We formally evaluate the Euclidean sum over geometries of chiral gravity and show that it gives precisely the holomorphic extremal CFT partition function. The modular invariance and integrality of the expansion coefficients of this partition function are consistent with the existence of an exact quantum theory of chiral gravity. We argue that the problem of quantizing chiral gravity is the holographic dual of the problem of constructing an extremal CFT, while quantizing log gravity is dual to the problem of constructing a logarithmic extremal CFT.

  6. Airborne laser scanning for high-resolution mapping of Antarctica

    NASA Astrophysics Data System (ADS)

    Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

    In order to evaluate the potential of airborne laser scanning for topographic mapping in Antarctica and to establish calibration/validation sites for NASA's Ice, Cloud and land Elevation Satellite (ICESat) altimeter mission, NASA, the U.S. National Science Foundation (NSF), and the U.S. Geological Survey (USGS) joined forces to collect high-resolution airborne laser scanning data.In a two-week campaign during the 2001-2002 austral summer, NASA's Airborne Topographic Mapper (ATM) system was used to collect data over several sites in the McMurdo Sound area of Antarctica (Figure 1a). From the recorded signals, NASA computed laser points and The Ohio State University (OSU) completed the elaborate computation/verification of high-resolution Digital Elevation Models (DEMs) in 2003. This article reports about the DEM generation and some exemplary results from scientists using the geomorphologic information from the DEMs during the 2003-2004 field season.

  7. A gravity survey of parts of quadrangles 26E, 26F, 27E, and 27F, northeastern Arabian Shield, Kingdom of Saudi Arabia

    USGS Publications Warehouse

    Miller, C.H.; Showail, A.A.; Kane, M.F.; Khoja, I.A.; Al Ghandi, S. A.

    1989-01-01

    The greatest complete Bouguer anomaly is associated with basaltic lava flows located in the northeastern part of the survey area. The thickness of the basalt in outcrop does not account for the anomalies with the highest amplitudes, but the latter may be due to the presence of a basalt-filled vent. Those anomalies that are present do not define the basalt flows well, but the largest free-air anomaly occurs over the southwestern margin of the Salma Caldera, located about 15 km from the basalt flows. The source of the free-air anomaly is unknown, but it may be related to another hidden basaltic vent.

  8. Feeling Gravity's Pull: Gravity Modeling. The Gravity Field of Mars

    NASA Astrophysics Data System (ADS)

    Lemoine, Frank; Smith, David; Rowlands, David; Zuber, Maria; Neumann, G.; Chinn, Douglas; Pavlis, D.

    2000-01-01

    Most people take the constant presence of gravitys pull for granted. However, the Earth's gravitational strength actually varies from location to location. This variation occurs because mass, which influences an object's gravitational pull, is not evenly distributed within the planet. Changes in topography, such as glacial movement, an earthquake, or a rise in the ocean level, can subtly affect the gravity field. An accurate measurement of the Earth's gravity field helps us understand the distribution of mass beneath the surface. This insight can assist us in locating petroleum, mineral deposits, ground water, and other valuable substances. Gravity mapping can also help notice or verify changes in sea surface height and other ocean characteristics. Such changes may indicate climate change from polar ice melting and other phenomena. In addition, gravity mapping can indicate how land moves under the surface after earthquakes and other plate tectonic processes. Finally, changes in the Earth's gravity field might indicate a shift in water distribution that could affect agriculture, water supplies for population centers, and long-term weather prediction. Scientists can map out the Earth's gravity field by watching satellite orbits. When a satellite shifts in vertical position, it might be passing over an area where gravity changes in strength. Gravity is only one factor that may shape a satellite's orbital path. To derive a gravity measurement from satellite movement, scientists must remove other factors that might affect a satellite's position: 1. Drag from atmospheric friction. 2. Pressure from solar radiation as it heads toward Earth and. as it is reflected off the surface of the Earth 3. Gravitational pull from the Sun, the Moon, and other planets in the Solar System. 4. The effect of tides. 5. Relativistic effects. Scientists must also correct for the satellite tracking process. For example, the tracking signal must be corrected for refraction through the

  9. Feeling Gravity's Pull: Gravity Modeling. The Gravity Field of Mars

    NASA Technical Reports Server (NTRS)

    Lemoine, Frank; Smith, David; Rowlands, David; Zuber, Maria; Neumann, G.; Chinn, Douglas; Pavlis, D.

    2000-01-01

    Most people take the constant presence of gravitys pull for granted. However, the Earth's gravitational strength actually varies from location to location. This variation occurs because mass, which influences an object's gravitational pull, is not evenly distributed within the planet. Changes in topography, such as glacial movement, an earthquake, or a rise in the ocean level, can subtly affect the gravity field. An accurate measurement of the Earth's gravity field helps us understand the distribution of mass beneath the surface. This insight can assist us in locating petroleum, mineral deposits, ground water, and other valuable substances. Gravity mapping can also help notice or verify changes in sea surface height and other ocean characteristics. Such changes may indicate climate change from polar ice melting and other phenomena. In addition, gravity mapping can indicate how land moves under the surface after earthquakes and other plate tectonic processes. Finally, changes in the Earth's gravity field might indicate a shift in water distribution that could affect agriculture, water supplies for population centers, and long-term weather prediction. Scientists can map out the Earth's gravity field by watching satellite orbits. When a satellite shifts in vertical position, it might be passing over an area where gravity changes in strength. Gravity is only one factor that may shape a satellite's orbital path. To derive a gravity measurement from satellite movement, scientists must remove other factors that might affect a satellite's position: 1. Drag from atmospheric friction. 2. Pressure from solar radiation as it heads toward Earth and. as it is reflected off the surface of the Earth 3. Gravitational pull from the Sun, the Moon, and other planets in the Solar System. 4. The effect of tides. 5. Relativistic effects. Scientists must also correct for the satellite tracking process. For example, the tracking signal must be corrected for refraction through the

  10. Airborne agent concentration analysis

    DOEpatents

    Gelbard, Fred

    2004-02-03

    A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

  11. Airborne Wind Turbine

    SciTech Connect

    2010-09-01

    Broad Funding Opportunity Announcement Project: Makani Power is developing an Airborne Wind Turbine (AWT) that eliminates 90% of the mass of a conventional wind turbine and accesses a stronger, more consistent wind at altitudes of near 1,000 feet. At these altitudes, 85% of the country can offer viable wind resources compared to only 15% accessible with current technology. Additionally, the Makani Power wing can be economically deployed in deep offshore waters, opening up a resource which is 4 times greater than the entire U.S. electrical generation capacity. Makani Power has demonstrated the core technology, including autonomous launch, land, and power generation with an 8 meter wingspan, 20 kW prototype. At commercial scale, Makani Power aims to develop a 600 kW, 28 meter wingspan product capable of delivering energy at an unsubsidized cost competitive with coal, the current benchmark for low-cost power.

  12. Airborne Cloud Computing Environment (ACCE)

    NASA Technical Reports Server (NTRS)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

  13. TR-GRAV: National Center for Turkish Gravity Field

    NASA Astrophysics Data System (ADS)

    Simav, Mehmet; Akpınar, İlyas; Sezen, Erdinc; Cingöz, Ayhan; Yıldız, Hasan

    2016-04-01

    TR-GRAV, the National Center for Turkish Gravity Field (TR-GRAV) that has recently become operational,is a national center that collects, processes and distributes Absolute Gravimetry,Relative Gravimetry, Airborne Gravimetry,Shipborne Gravimetry,Satellite Gravimetry, GNSS/Levelling, Astrogeodetic Vertical Deflection data to model and improve regional gravity field for the Turkish territory and its surrounding regions and to provide accurate, consistent and value-added data & products to the scientific and engineering communities. In this presentation, we will introduce the center web portal and give some details about the database.

  14. 2006 Compilation of Alaska Gravity Data and Historical Reports

    USGS Publications Warehouse

    Saltus, Richard W.; Brown, Philip J.; Morin, Robert L.; Hill, Patricia L.

    2008-01-01

    Gravity anomalies provide fundamental geophysical information about Earth structure and dynamics. To increase geologic and geodynamic understanding of Alaska, the U.S. Geological Survey (USGS) has collected and processed Alaska gravity data for the past 50 years. This report introduces and describes an integrated, State-wide gravity database and provides accompanying gravity calculation tools to assist in its application. Additional information includes gravity base station descriptions and digital scans of historical USGS reports. The gravity calculation tools enable the user to reduce new gravity data in a consistent manner for combination with the existing database. This database has sufficient resolution to define the regional gravity anomalies of Alaska. Interpretation of regional gravity anomalies in parts of the State are hampered by the lack of local isostatic compensation in both southern and northern Alaska. However, when filtered appropriately, the Alaska gravity data show regional features having geologic significance. These features include gravity lows caused by low-density rocks of Cenozoic basins, flysch belts, and felsic intrusions, as well as many gravity highs associated with high-density mafic and ultramafic complexes.

  15. Magnetic, gravity, radiometric, LiDAR, and seismic data to characterize the region of the M5.8 August 23, 2011 earthquake near Mineral, Virginia

    NASA Astrophysics Data System (ADS)

    Shah, A. K.; McNamara, D. E.; Odum, J. K.; Stephenson, W. J.; Kayen, R. E.; Emmett, P. F.; Herrmann, R. B.; Snyder, S. L.; Horton, J. W.; Williams, R. A.

    2012-12-01

    In response to the M5.8 August 23, 2011 Mineral, VA earthquake, the U.S. Geological Survey and partner organizations acquired or sponsored collection of several geophysical datasets to assist characterization of the earthquake region. Goals include the mapping of the main shock causative and aftershock faults as well as associated geologic features which may be buried or difficult to access, estimates of regional ground motion attenuation, and measurements describing local amplification of seismic energy. The deployment of 46 portable seismic stations by several organizations within days following the earthquake, along with public availability of the resulting data, has greatly aided site characterization efforts. The aftershock data recorded by these stations have allowed delineation of the probable causative fault and other faults that were active afterwards. Using the portable seismograph network and regional permanent stations, S and Lg waves were analyzed to estimate crustal attenuation characteristics. Active- and passive-source seismic experiments were also conducted at many of the portable and permanent stations to characterize site conditions and constrain local response models via estimates of Vs30 and bedrock depth. In March 2012, a LiDAR survey with 8pt/m2 resolution was flown over a ~20x35 km area covering the epicenters of the earthquake and most aftershocks. In July 2012, a high-resolution airborne magnetic, gravity, and radiometric survey was flown over a similar but slightly smaller area. Supplementary ground gravity data have been collected inside and outside of the airborne survey areas. The gravity and magnetic data reflect subsurface features in a region where outcropping rocks are sparse, while LiDAR and radiometric data, respectively, delineate subtle features at the land surface and upper few centimeters. Each of these datasets reflects the regional NE-SW striking fabric. Seismic wave analyses show preferential attenuation in a NW

  16. Precision gravity networks at Lassen Peak and Mount Shasta, California

    USGS Publications Warehouse

    Jachens, Robert C.; Dzurisin, Daniel; Elder, W.P.; Saltus, R.W.

    1983-01-01

    Reoccupiable precision gravity networks for the purpose of monitoring volcanic activity were established in the vicinity of Lassen Peak and Mt. Shasta. Base-line measurements were made during the summer of 1981, nearly coincident in time with other base-line geodetic measurements. The gravity surveys yielded gravity values at network stations relative to local bases with typical uncertainties of 0.007 mGal (1 computed standard error).

  17. Gravity's Smoking Gun?

    NASA Astrophysics Data System (ADS)

    Gaztañaga, Enrique; Juszkiewicz, Roman

    2001-09-01

    We present a new constraint on the biased galaxy formation picture. Gravitational instability theory predicts that the two-point mass density correlation function, ξ(r), has an inflection point at the separation r=r0, corresponding to the boundary between the linear and nonlinear regime of clustering, ξ~=1. We show how this feature can be used to constrain the biasing parameter b2≡ξg(r)/ξ(r) on scales r~=r0, where ξg is the galaxy-galaxy correlation function, which is allowed to differ from ξ. We apply our method to real data: the ξg(r), estimated from the Automatic Plate Measuring (APM) galaxy survey. Our results suggest that the APM galaxies trace the mass at separations r>~5 h-1 Mpc, where h is the Hubble constant in units of 100 km s-1 Mpc-1. The present results agree with earlier studies, based on comparing higher order correlations in the APM with weakly nonlinear perturbation theory. Both approaches constrain the b factor to be within 20% of unity. If the existence of the feature that we identified in the APM ξg(r)-the inflection point near ξg=1-is confirmed by more accurate surveys, we may have discovered gravity's smoking gun: the long-awaited ``shoulder'' in ξ, predicted by Gott and Rees 25 years ago.

  18. Physics of Artificial Gravity

    NASA Technical Reports Server (NTRS)

    Bukley, Angie; Paloski, William; Clement, Gilles

    2006-01-01

    This chapter discusses potential technologies for achieving artificial gravity in a space vehicle. We begin with a series of definitions and a general description of the rotational dynamics behind the forces ultimately exerted on the human body during centrifugation, such as gravity level, gravity gradient, and Coriolis force. Human factors considerations and comfort limits associated with a rotating environment are then discussed. Finally, engineering options for designing space vehicles with artificial gravity are presented.

  19. Terrestrial Gravity Fluctuations

    NASA Astrophysics Data System (ADS)

    Harms, Jan

    2015-12-01

    Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW) detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10‑23 Hz‑1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of

  20. Gravity is Geometry.

    ERIC Educational Resources Information Center

    MacKeown, P. K.

    1984-01-01

    Clarifies two concepts of gravity--those of a fictitious force and those of how space and time may have geometry. Reviews the position of Newton's theory of gravity in the context of special relativity and considers why gravity (as distinct from electromagnetics) lends itself to Einstein's revolutionary interpretation. (JN)

  1. Challenging Entropic Gravity

    NASA Astrophysics Data System (ADS)

    Roveto, Jonathan

    2011-11-01

    A recent proposal by Erik Verlinde claims that gravity should be viewed not as a fundamental force, but an emergent thermodynamic phenomenon due to some yet undetermined microscopic theory. We present a challenge to this reformulation of gravity. Our claim is that a detailed derivation using Verlinde's proposed theory fails to correctly give Newton's laws or Einstein gravity.

  2. Airborne Particulate Threat Assessment

    SciTech Connect

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

    Aerosol threat detection requires the ability to discern between threat agents and ambient background particulate matter (PM) encountered in the environment. To date, Raman imaging technology has been demonstrated as an effective strategy for the assessment of threat agents in the presence of specific, complex backgrounds. Expanding our understanding of the composition of ambient particulate matter background will improve the overall performance of Raman Chemical Imaging (RCI) detection strategies for the autonomous detection of airborne chemical and biological hazards. Improving RCI detection performance is strategic due to its potential to become a widely exploited detection approach by several U.S. government agencies. To improve the understanding of the ambient PM background with subsequent improvement in Raman threat detection capability, ChemImage undertook the Airborne Particulate Threat Assessment (APTA) Project in 2005-2008 through a collaborative effort with the National Energy Technology Laboratory (NETL), under cooperative agreement number DE-FC26-05NT42594. During Phase 1 of the program, a novel PM classification based on molecular composition was developed based on a comprehensive review of the scientific literature. In addition, testing protocols were developed for ambient PM characterization. A signature database was developed based on a variety of microanalytical techniques, including scanning electron microscopy, FT-IR microspectroscopy, optical microscopy, fluorescence and Raman chemical imaging techniques. An automated particle integrated collector and detector (APICD) prototype was developed for automated collection, deposition and detection of biothreat agents in background PM. During Phase 2 of the program, ChemImage continued to refine the understanding of ambient background composition. Additionally, ChemImage enhanced the APICD to provide improved autonomy, sensitivity and specificity. Deliverables included a Final Report detailing our

  3. Rapid approximate inversion of airborne TEM

    NASA Astrophysics Data System (ADS)

    Fullagar, Peter K.; Pears, Glenn A.; Reid, James E.; Schaa, Ralf

    2015-11-01

    Rapid interpretation of large airborne transient electromagnetic (ATEM) datasets is highly desirable for timely decision-making in exploration. Full solution 3D inversion of entire airborne electromagnetic (AEM) surveys is often still not feasible on current day PCs. Therefore, two algorithms to perform rapid approximate 3D interpretation of AEM have been developed. The loss of rigour may be of little consequence if the objective of the AEM survey is regional reconnaissance. Data coverage is often quasi-2D rather than truly 3D in such cases, belying the need for `exact' 3D inversion. Incorporation of geological constraints reduces the non-uniqueness of 3D AEM inversion. Integrated interpretation can be achieved most readily when inversion is applied to a geological model, attributed with lithology as well as conductivity. Geological models also offer several practical advantages over pure property models during inversion. In particular, they permit adjustment of geological boundaries. In addition, optimal conductivities can be determined for homogeneous units. Both algorithms described here can operate on geological models; however, they can also perform `unconstrained' inversion if the geological context is unknown. VPem1D performs 1D inversion at each ATEM data location above a 3D model. Interpretation of cover thickness is a natural application; this is illustrated via application to Spectrem data from central Australia. VPem3D performs 3D inversion on time-integrated (resistive limit) data. Conversion to resistive limits delivers a massive increase in speed since the TEM inverse problem reduces to a quasi-magnetic problem. The time evolution of the decay is lost during the conversion, but the information can be largely recovered by constructing a starting model from conductivity depth images (CDIs) or 1D inversions combined with geological constraints if available. The efficacy of the approach is demonstrated on Spectrem data from Brazil. Both separately and in

  4. Airborne GLM Simulator (FEGS)

    NASA Astrophysics Data System (ADS)

    Quick, M.; Blakeslee, R. J.; Christian, H. J., Jr.; Stewart, M. F.; Podgorny, S.; Corredor, D.

    2015-12-01

    Real time lightning observations have proven to be useful for advanced warning and now-casting of severe weather events. In anticipation of the launch of the Geostationary Lightning Mapper (GLM) onboard GOES-R that will provide continuous real time observations of total (both cloud and ground) lightning, the Fly's Eye GLM Simulator (FEGS) is in production. FEGS is an airborne instrument designed to provide cal/val measurements for GLM from high altitude aircraft. It consists of a 5 x 5 array of telescopes each with a narrow passband filter to isolate the 777.4 nm neutral oxygen emission triplet radiated by lightning. The telescopes will measure the optical radiance emitted by lightning that is transmitted through the cloud top with a temporal resolution of 10 μs. When integrated on the NASA ER-2 aircraft, the FEGS array with its 90° field-of-view will observe a cloud top area nearly equal to a single GLM pixel. This design will allow FEGS to determine the temporal and spatial variation of light that contributes to a GLM event detection. In addition to the primary telescope array, the instrument includes 5 supplementary optical channels that observe alternate spectral emission features and will enable the use of FEGS for interesting lightning physics applications. Here we present an up-to-date summary of the project and a description of its scientific applications.

  5. Airborne Laser/GPS Mapping of Assateague National Seashore Beach

    NASA Technical Reports Server (NTRS)

    Kradill, W. B.; Wright, C. W.; Brock, John C.; Swift, R. N.; Frederick, E. B.; Manizade, S. S.; Yungel, J. K.; Martin, C. F.; Sonntag, J. G.; Duffy, Mark; Hulslander, William

    1997-01-01

    Results are presented from topographic surveys of the Assateague Island National Seashore using recently developed Airborne Topographic Mapper (ATM) and kinematic Global Positioning System (GPS) technology. In November, 1995, and again in May, 1996, the NASA Arctic Ice Mapping (AIM) group from the Goddard Space Flight Center's Wallops Flight Facility conducted the topographic surveys as a part of technology enhancement activities prior to conducting missions to measure the elevation of extensive sections of the Greenland Ice Sheet as part of NASA's Global Climate Change program. Differences between overlapping portions of both surveys are compared for quality control. An independent assessment of the accuracy of the ATM survey is provided by comparison to surface surveys which were conducted using standard techniques. The goal of these projects is to mdke these measurements to an accuracy of +/- 10 cm. Differences between the fall 1995 and 1996 surveys provides an assessment of net changes in the beach morphology over an annual cycle.

  6. Localized Temporal Gravity Investigations at Long Valley Caldera

    NASA Astrophysics Data System (ADS)

    Markiel, J. M.; Gabbert, R.; Smith, E.; Ingalls, S.; Beale, J.; Factor, J.; Holmes, S. A.

    2012-12-01

    Accurately modeling temporal changes in the gravity field of the Earth is now a central concern of modern geodesy. Investigations in temporal gravity are currently the focus of considerable research on a global basis as reported by the IAG, Commission 2.2: Gravity Field [IAG, 2011]. These large scale investigations utilizing the GRACE/GOCE satellite datasets have demonstrated considerable time dependent variations in gravity as the result of mass changes, most notably owing to variations in water/ice regimes. However, these gravity missions are relatively recent, and so the length of the temporal period is limited to sub-decadal extent. Similarly, the long wavelength resolution of the satellite data precludes the derivation of a spatially dense, localized gravity model. The analysis of gravity changes on a localized basis is quite limited owing to the lack of quality gravity collections over a period of decades. Investigations over decadal time periods are accordingly unique. In this paper, we report the results of our recent investigations at Long Valley Caldera, California, USA with respect to localized temporal gravity changes. Leveraging early gravity acquisitions by Jachens and Roberts [1985] and Battaglia, et al, [2003], we analyze the recent (2012) gravity collections to establish a three decade study of gravity changes at the Long Valley Caldera site. Since all the data was collected at the same locations for each gravity survey (1982~1985, 1999, 2012), the resulting study is able to minimize errors associated with interpolation. Additionally, we compare the recent localized gravity model with the GRACE/GOCE gravity signature and analyze the correlation between the local and global models. Approved for public release 12-430

  7. Comparison of airborne lidar measurements with 420 kHz echo-sounder measurements of zooplankton.

    PubMed

    Churnside, James H; Thorne, Richard E

    2005-09-10

    Airborne lidar has the potential to survey large areas quickly and at a low cost per kilometer along a survey line. For this reason, we investigated the performance of an airborne lidar for surveys of zooplankton. In particular, we compared the lidar returns with echo-sounder measurements of zooplankton in Prince William Sound, Alaska. Data from eight regions of the Sound were compared, and the correlation between the two methods was 0.78. To obtain this level of agreement, a threshold was applied to the lidar return to remove the effects of scattering from phytoplankton. PMID:16161666

  8. Laboratory analysis and airborne detection of materials stimulated to luminesce by the sun

    USGS Publications Warehouse

    Hemphill, W.R.; Theisen, A.F.; Tyson, R.M.

    1984-01-01

    The Fraunhofer line discriminator (FLD) is an airborne electro-optical device used to image materials which have been stimulated to luminesce by the Sun. Such materials include uranium-bearing sandstone, sedimentary phosphate rock, marine oil seeps, and stressed vegetation. Prior to conducting an airborne survey, a fluorescence spectrometer may be used in the laboratory to determine the spectral region where samples of the target material exhibit maximum luminescence, and to select the optimum Fraunhofer line. ?? 1984.

  9. Gravity Signature of the Teague Ring Impact Structure, Western Australia

    NASA Technical Reports Server (NTRS)

    Plescia, J. B.

    1998-01-01

    As part of a multidisciplinary effort to better define the nature of the Teague Ring structure and to understand specifics about the crustal structure, a GPS controlled gravity survey of the feature was undertaken in the austral winter of 1996.

  10. How two gravity-gradient inversion methods can be used to reveal different geologic features of ore deposit - A case study from the Quadrilátero Ferrífero (Brazil)

    NASA Astrophysics Data System (ADS)

    Carlos, Dionísio U.; Uieda, Leonardo; Barbosa, Valeria C. F.

    2016-07-01

    Airborne gravity gradiometry data have been recently used in mining surveys to map the 3D geometry of ore deposits. This task can be achieved by different gravity-gradient inversion methods, many of which use a voxel-based discretization of the Earth's subsurface. To produce a unique and stable solution, an inversion method introduces particular constraints. One constraining inversion introduces a depth-weighting function in the first-order Tikhonov regularization imposing a smoothing on the density-contrast distributions that are not restricted to near-surface regions. Another gravity-gradient inversion, the method of planting anomalous densities, imposes compactness and sharp boundaries on the density-contrast distributions. We used these two inversion methods to invert the airborne gravity-gradient data over the iron-ore deposit at the southern flank of the Gandarela syncline in Quadrilátero Ferrífero (Brazil). Because these methods differ from each other in the particular constraint used, the estimated 3D density-contrast distributions reveal different geologic features of ore deposit. The depth-weighting smoothing inversion reveals variable dip directions along the strike of the retrieved iron-ore body. The planting anomalous density inversion estimates a compact iron-ore mass with a single density contrast, which reveals a variable volume of the iron ore along its strike increasing towards the hinge zone of the Gandarela syncline which is the zone of maximum compression. The combination of the geologic features inferred from each estimate leads to a synergistic effect, revealing that the iron-ore deposit is strongly controlled by the Gandarela syncline.

  11. Basement and Basin Structures of the Northwest Paraná Basin, Brazil: Illuminated by Matched-Filter Analysis and 2D Modeling of Gravity and Magnetic Data

    NASA Astrophysics Data System (ADS)

    Curto, J. B.; Blakely, R. J.; Vidotti, R. M.; Fuck, R. A.

    2015-12-01

    The South American Platform includes two major geological components with common structural roots: the Transbrasiliano Lineament (LTB) and the Paraná Basin. Important relationships between the two components occur within the northwest Paraná Basin and concealed beneath sedimentary cover. We integrated all available airborne magnetic and gravity surveys and ground-based gravity data to produce consistent, digital magnetic and Bouguer anomaly maps. Data-processing and modeling techniques then were used in order to reveal principal crustal compartments and basin-basement structures at various depths. Three large magnetic discontinuities delineate crustal compartments in the area with N30°E, N60°E, and N70°E strike, from east to west, respectively. These magnetic lineaments bound regions with distinct gravity anomaly character. Robust matched-filter analysis applied to magnetic and gravity data yielded important depth estimates: (i) 2.5 km to the top of the Paraná Basin Neoproterozoic basement; (ii) 4-6 km to the top of a second group of basement units; (iii) 20 km, possibly associated with the upper-lower crust interface; and (iv) 33-39 and 43 km related to crustal thicknesses west and southeast of a major N30°E trending lineament, respectively. The 2D joint modeling of gravity and magnetic data sheds light on the asymmetric geometry of the basement beneath the Paraná basin, with at least three half-grabens formed by LTB reactivated structures. The central region of the study area is characterized by thinner crust and higher crustal weakness, where important structures have developed in the Mesozoic, including NW trending reactivations, linked to crustal uplift and evolution of small NE-aligned Cretaceous basins. Important depocenters occur to the north and east of the study area, with N70ºE and N30°E - NS strike, respectively.

  12. Airborne Laser Polar Nephelometer

    NASA Technical Reports Server (NTRS)

    Grams, Gerald W.

    1973-01-01

    A polar nephelometer has been developed at NCAR to measure the angular variation of the intensity of light scattered by air molecules and particles. The system has been designed for airborne measurements using outside air ducted through a 5-cm diameter airflow tube; the sample volume is that which is common to the intersection of a collimated source beam and the detector field of view within the airflow tube. The source is a linearly polarized helium-neon laser beam. The optical system defines a collimated field-of-view (0.5deg half-angle) through a series of diaphragms located behind a I72-mm focal length objective lens. A photomultiplier tube is located immediately behind an aperture in the focal plane of the objective lens. The laser beam is mechanically chopped (on-off) at a rate of 5 Hz; a two-channel pulse counter, synchronized to the laser output, measures the photomultiplier pulse rate with the light beam both on and off. The difference in these measured pulse rates is directly proportional to the intensity of the scattered light from the volume common to the intersection of the laser beam and the detector field-of-view. Measurements can be made at scattering angles from 15deg to 165deg with reference to the direction of propagation of the light beam. Intermediate angles are obtained by selecting the angular increments desired between these extreme angles (any multiple of 0.1deg can be selected for the angular increment; 5deg is used in normal operation). Pulses provided by digital circuits control a stepping motor which sequentially rotates the detector by pre-selected angular increments. The synchronous photon-counting system automatically begins measurement of the scattered-light intensity immediately after the rotation to a new angle has been completed. The instrument has been flown on the NASA Convair 990 airborne laboratory to obtain data on the complex index of refraction of atmospheric aerosols. A particle impaction device is operated simultaneously

  13. Airborne thermography for condition monitoring of a public baths building

    NASA Astrophysics Data System (ADS)

    Mattsson, Mats; Hellman, Erik; Ljungberg, Sven-Ake

    2001-03-01

    Airborne and ground-based thermography surveys have been performed in order to detect moisture and energy related problems in the construction of a public swimming bath building. This paper describes the information potential and the advantages and limitations using a standard IR-camera and traditional inspection methods to gather information for retrofit priorities. The damage conditions indicated in the thermal images are confirmed by field inspections and photographic documentation.

  14. Reducing risk in deep-water exploration with ALF, the Airborne Laser Fluorosensor

    SciTech Connect

    Williams, A.K.

    1995-12-31

    The vast majority of the world`s onshore oilfields leak small amounts of petroleum as surface seeps. Seeps mark the ends of migration pathways and in unexplored basins, they provide vital clues in the hunt for the oilfields of the future. ALF, the Airborne Laser Fluorosensor, is an airborne geochemical tool capable of detecting very low concentrations of seeped petroleum at the ocean surface, equivalent to micro-seepage levels detected by conventional surface geochemical tools (gravity coring, etc). The system has detected oil and condensate films as thin as 0.01{mu}m (microns), an order of magnitude less than observed by the human eye or by passive satellite or airborne sensors as below 0.1{mu}m, oil films are invisible. ALF also identifies the phase of the seeping petroleum i.e., light oil/condensate, normal or heavy oil.

  15. NASA Airborne Science Program: NASA Stratospheric Platforms

    NASA Technical Reports Server (NTRS)

    Curry, Robert E.

    2010-01-01

    The National Aeronautics and Space Administration conducts a wide variety of remote sensing projects using several unique aircraft platforms. These vehicles have been selected and modified to provide capabilities that are particularly important for geophysical research, in particular, routine access to very high altitudes, long range, long endurance, precise trajectory control, and the payload capacity to operate multiple, diverse instruments concurrently. While the NASA program has been in operation for over 30 years, new aircraft and technological advances that will expand the capabilities for airborne observation are continually being assessed and implemented. This presentation will review the current state of NASA's science platforms, recent improvements and new missions concepts as well as provide a survey of emerging technologies unmanned aerial vehicles for long duration observations (Global Hawk and Predator). Applications of information technology that allow more efficient use of flight time and the ability to rapidly reconfigure systems for different mission objectives are addressed.

  16. 43 CFR 3836.13 - What are geological, geochemical, or geophysical surveys?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... anomalous mineral values and quantities that may in turn identify mineral deposits. (c) Geophysical surveys are surveys of the physical characteristics of mineral deposits to measure physical differences... other things, magnetic and electromagnetic surveys, gravity surveys, seismic surveys, and...

  17. 43 CFR 3836.13 - What are geological, geochemical, or geophysical surveys?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... anomalous mineral values and quantities that may in turn identify mineral deposits. (c) Geophysical surveys are surveys of the physical characteristics of mineral deposits to measure physical differences... other things, magnetic and electromagnetic surveys, gravity surveys, seismic surveys, and...

  18. 43 CFR 3836.13 - What are geological, geochemical, or geophysical surveys?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... anomalous mineral values and quantities that may in turn identify mineral deposits. (c) Geophysical surveys are surveys of the physical characteristics of mineral deposits to measure physical differences... other things, magnetic and electromagnetic surveys, gravity surveys, seismic surveys, and...

  19. Gravity changes and natural gas extraction in Groningen

    SciTech Connect

    Gelderen, M. van; Haagmans, R.; Bilker, M.

    1999-11-01

    Gravity observations made over the Groningen gas field from 1978 onwards are available. The existing gravity data were reanalyzed and a new survey was carried out. The observed gravity changes obtained during four surveys, spanning an 18-year period, were compared with the gravity effect due to natural gas extraction computed from the reservoir model and the production data. The random error in the gravity values is small enough to detect the effect of gas extraction after a few years (up to 2 {micro}gal/year). The trends obtained from observed and calculated gravity changes agree well within their expected error margins after statistical data snooping. Due to the inadequate measurement set-up of the previous surveys, systematic errors present in gravity data hampered the use of this data for refinement of the reservoir and the production models. However, with improved gravity monitoring, in particular a very systematic network set-up and well-calibrated instruments, this should now be feasible. By using the network analysis from the 1996 measurements for the planning of a network in space and time, most of the current problems can be avoided.

  20. High Resolution Airborne Shallow Water Mapping

    NASA Astrophysics Data System (ADS)

    Steinbacher, F.; Pfennigbauer, M.; Aufleger, M.; Ullrich, A.

    2012-07-01

    In order to meet the requirements of the European Water Framework Directive (EU-WFD), authorities face the problem of repeatedly performing area-wide surveying of all kinds of inland waters. Especially for mid-sized or small rivers this is a considerable challenge imposing insurmountable logistical efforts and costs. It is therefore investigated if large-scale surveying of a river system on an operational basis is feasible by employing airborne hydrographic laser scanning. In cooperation with the Bavarian Water Authority (WWA Weilheim) a pilot project was initiated by the Unit of Hydraulic Engineering at the University of Innsbruck and RIEGL Laser Measurement Systems exploiting the possibilities of a new LIDAR measurement system with high spatial resolution and high measurement rate to capture about 70 km of riverbed and foreland for the river Loisach in Bavaria/Germany and the estuary and parts of the shoreline (about 40km in length) of lake Ammersee. The entire area surveyed was referenced to classic terrestrial cross-section surveys with the aim to derive products for the monitoring and managing needs of the inland water bodies forced by the EU-WFD. The survey was performed in July 2011 by helicopter and airplane and took 3 days in total. In addition, high resolution areal images were taken to provide an optical reference, offering a wide range of possibilities on further research, monitoring, and managing responsibilities. The operating altitude was about 500 m to maintain eye-safety, even for the aided eye, the airspeed was about 55 kts for the helicopter and 75 kts for the aircraft. The helicopter was used in the alpine regions while the fixed wing aircraft was used in the plains and the urban area, using appropriate scan rates to receive evenly distributed point clouds. The resulting point density ranged from 10 to 25 points per square meter. By carefully selecting days with optimum water quality, satisfactory penetration down to the river bed was achieved

  1. An airborne isothermal haze chamber

    NASA Technical Reports Server (NTRS)

    Hindman, E. E.

    1981-01-01

    Thermal gradient diffusion cloud chambers (TGDCC) are used to determine the concentrations of cloud condensation nuclei (CCN) with critical supersaturations greater than or equal to about 0.2%. The CCN concentrations measured with the airborne IHC were lower than theoretically predicted by factors ranging between 7.9 and 9.0. The CCN concentrations measured with the airborne IHC were lower than the concentrations measured with the larger laboratory IHC's by factors ranging between 3.9 and 7.5. The bounds of the supersaturation ranges of the airborne IHC and the CSU-Mee TGDCC do not overlap. Nevertheless, the slopes of the interpolated data between the bounds agree favorably with the theoretical slopes.

  2. WESTERN AIRBORNE CONTAMINANTS ASSESSMENT PROJECT RESEARCH PLAN

    EPA Science Inventory

    The goal of the Western Airborne Contaminants Assessment Project (WACAP) is to assess the deposition of airborne contaminants in Western National Parks, providing regional and local information on exposure, accumulation, impacts, and probable sources. This project is being desig...

  3. A Gravity data along LARSE (Los Angeles Regional Seismic Experiment) Line II, Southern California

    USGS Publications Warehouse

    Wooley, R.J.; Langenheim, V.E.

    2001-01-01

    The U.S. Geological Survey conducted a detailed gravity study along part of the Los Angeles Regional Seismic Experiment (LARSE) transect across the San Fernando Basin and Transverse Ranges to help characterize the structure underlying this area. 249 gravity measurements were collected along the transect and to augment regional coverage near the profile. An isostatic gravity low of 50-60 mGal reflects the San Fernando-East Ventura basin. Another prominent isostatic gravity with an amplitude of 30 mGal marks the Antelope Valley basin. Gravity highs occur over the Santa Monica Mountains and the Transverse Ranges. The highest isostatic gravity values coincide with outcrops of Pelona schist.

  4. Airborne laser mapping of Assateague National Seashore Beach

    USGS Publications Warehouse

    Krabill, W.B.; Wright, C.W.; Swift, R.N.; Frederick, E.B.; Manizade, S.S.; Yungel, J.K.; Martin, C.F.; Sonntag, J.G.; Duffy, Mark; Hulslander, William; Brock, John C.

    2000-01-01

    Results are presented from topographic surveys of the Assateague Island National Seashore using an airborne scanning laser altimeter and kinematic Global Positioning System (GPS) technology. The instrument used was the Airborne Topographic Mapper (ATM), developed by the NASA Arctic Ice Mapping (AIM) group from the Goddard Space Flight Center's Wallops Flight Facility. In November, 1995, and again in May, 1996, these topographic surveys were flown as a functionality check prior to conducting missions to measure the elevation of extensive sections of the Greenland Ice Sheet as part of NASA's Global Climate Change program. Differences between overlapping portions of both surveys are compared for quality control. An independent assessment of the accuracy of the ATM survey is provided by comparison to surface surveys which were conducted using standard techniques. The goal of these projects is to make these measurements to an accuracy of ± 10 cm. Differences between the fall 1995 and 1996 surveys provides an assessment of net changes in the beach morphology over an annual cycle.

  5. Airborne Transmission of Bordetella pertussis

    PubMed Central

    Warfel, Jason M.; Beren, Joel; Merkel, Tod J.

    2012-01-01

    Pertussis is a contagious, acute respiratory illness caused by the bacterial pathogen Bordetella pertussis. Although it is widely believed that transmission of B. pertussis occurs via aerosolized respiratory droplets, no controlled study has ever documented airborne transmission of pertussis. We set out to determine if airborne transmission occurs between infected and naive animals, utilizing the baboon model of pertussis. Our results showed that 100% of exposed naive animals became infected even when physical contact was prevented, demonstrating that pertussis transmission occurs via aerosolized respiratory droplets. PMID:22807521

  6. Mismatch in aeroallergens and airborne grass pollen concentrations

    NASA Astrophysics Data System (ADS)

    Plaza, M. P.; Alcázar, P.; Hernández-Ceballos, M. A.; Galán, C.

    2016-11-01

    An accurate estimation of the allergen concentration in the atmosphere is essential for allergy sufferers. The major cause of pollinosis all over Europe is due to grass pollen and Phl p 5 has the highest rates of sensitization (>50%) in patients with grass pollen-induced allergy. However, recent research has shown that airborne pollen does not always offer a clear indicator of exposure to aeroallergens. This study aims to evaluate relations between airborne grass pollen and Phl p 5 concentrations in Córdoba (southern Spain) and to study how meteorological parameters influence these atmospheric records. Monitoring was carried out from 2012 to 2014. Hirst-type volumetric spore trap was used for pollen collection, following the protocol recommended by the Spanish Aerobiology Network (REA). Aeroallergen sampling was performed using a low-volume cyclone sampler, and allergenic particles were quantified by ELISA assay. Besides, the influence of main meteorological factors on local airborne pollen and allergen concentrations was surveyed. A significant correlation was observed between grass pollen and Phl p 5 allergen concentrations during the pollen season, but with some sporadic discrepancy episodes. The cumulative annual Pollen Index also varied considerably. A significant correlation has been obtained between airborne pollen and minimum temperature, relative humidity and precipitation, during the three studied years. However, there is no clear relationship between allergens and weather variables. Our findings suggest that the correlation between grass pollen and aeroallergen Phl p 5 concentrations varies from year-to-year probably related to a complex interplay of meteorological variables.

  7. Evaluation of airborne topographic lidar for quantifying beach changes

    USGS Publications Warehouse

    Sallenger, A.H.; Krabill, W.B.; Swift, R.N.; Brock, J.; List, J.; Hansen, M.; Holman, R.A.; Manizade, S.; Sontag, J.; Meredith, A.; Morgan, K.; Yunkel, J.K.; Frederick, E.B.; Stockdon, H.

    2003-01-01

    A scanning airborne topographic lidar was evaluated for its ability to quantify beach topography and changes during the Sandy Duck experiment in 1997 along the North Carolina coast. Elevation estimates, acquired with NASA's Airborne Topographic Mapper (ATM), were compared to elevations measured with three types of ground-based measurements - 1) differential GPS equipped all-terrain vehicle (ATV) that surveyed a 3-km reach of beach from the shoreline to the dune, 2) GPS antenna mounted on a stadia rod used to intensely survey a different 100 m reach of beach, and 3) a second GPS-equipped ATV that surveyed a 70-km-long transect along the coast. Over 40,000 individual intercomparisons between ATM and ground surveys were calculated. RMS vertical differences associated with the ATM when compared to ground measurements ranged from 13 to 19 cm. Considering all of the intercomparisons together, RMS ??? 15 cm. This RMS error represents a total error for individual elevation estimates including uncertainties associated with random and mean errors. The latter was the largest source of error and was attributed to drift in differential GPS. The ??? 15 cm vertical accuracy of the ATM is adequate to resolve beach-change signals typical of the impact of storms. For example, ATM surveys of Assateague Island (spanning the border of MD and VA) prior to and immediately following a severe northeaster showed vertical beach changes in places greater than 2 m, much greater than expected errors associated with the ATM. A major asset of airborne lidar is the high spatial data density. Measurements of elevation are acquired every few m2 over regional scales of hundreds of kilometers. Hence, many scales of beach morphology and change can be resolved, from beach cusps tens of meters in wavelength to entire coastal cells comprising tens to hundreds of kilometers of coast. Topographic lidars similar to the ATM are becoming increasingly available from commercial vendors and should, in the future

  8. Interpretation of Local Gravity Anomalies in Northern New York

    NASA Astrophysics Data System (ADS)

    Revetta, F. A.

    2004-05-01

    About 10,000 new gravity measurements at a station spacing of 1 to 2 Km were made in the Adirondack Mountains, Lake Champlain Valley, St. Lawrence River Valley and Tug Hill Plateau. These closely spaced gravity measurements were compiled to construct computer contoured gravity maps of the survey areas. The gravity measurements reveal local anomalies related to seismicity, faults, mineral resources and gas fields that are not seen in the regional gravity mapping. In northern New York gravity and seismicity maps indicate epicenters are concentrated in areas of the most pronounced gravity anomalies along steep gravity gradients. Zones of weakness along the contacts of these lithologies of different density could possibly account for the earthquakes in this high stress area. Also, a computer contoured gravity map of the 5.3 magnitude Au Sable Forks earthquake of April 20, 2002 indicates the epicenter lies along a north-south trending gravity gradient produced by a high angle fault structure separating a gravity low in the west from high gravity in the east. In the St. Lawrence Valley, the Carthage-Colton Mylonite Zone, a major northeast trending structural boundary between the Adirondack Highlands and Northwest Lowlands, is represented as a steep gravity gradient extending into the eastern shore of Lake Ontario. At Russell, New York near the CCMZ, a small circular shaped gravity high coincides with a cluster of earthquakes. The coincidence of the epicenters over the high may indicate stress amplification at the boundary of a gabbro pluton. The Morristown fault located in the Morristown Quadrangle in St. Lawrence County produces both gravity and magnetic anomalies due to Precambrian Basement faulting. This faulting indicates control of the Morristown fault in the overlying Paleozoics by the Precambrian faults. Gravity and magnetic anomalies also occur over proposed extensions of the Gloucester and Winchester Springs faults into northern New York. Gravity and magnetic

  9. Airborne measured analytic signal for UXO detection

    SciTech Connect

    Gamey, T.J.; Holladay, J.S.; Mahler, R.

    1997-10-01

    The Altmark Tank Training Range north of Haldensleben, Germany has been in operation since WWI. Weapons training and testing has included cavalry, cannon, small arms, rail guns, and tank battalions. Current plans are to convert the area to a fully digital combat training facility. Instead of using blank or dummy ordnance, hits will be registered with lasers and computers. Before this can happen, the 25,000 ha must be cleared of old debris. In support of this cleanup operation, Aerodat Inc., in conjunction with IABG of Germany, demonstrated a new high resolution magnetic survey technique involving the measurement of 3-component magnetic gradient data. The survey was conducted in May 1996, and covered 500 ha in two blocks. The nominal line spacing was 10 m, and the average sensor altitude was 7 m. The geologic column consisted of sands over a sedimentary basin. Topographic relief was generally flat with approximately 3 m rolling dunes and occasional man-made features such as fox holes, bunkers, tank traps and reviewing stands. Trees were sparse and short (2-3 metres) due to frequent burn off and tank activity. As such, this site was nearly ideal for low altitude airborne surveying.

  10. NASA Airborne Lidar 1982-1984 Flights

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar 1982-1984 Flights Data from the 1982 NASA Langley Airborne Lidar flights following the eruption of El Chichon ... continuing to January 1984. Transcribed from the following NASA Tech Reports: McCormick, M. P., and M. T. Osborn, Airborne lidar ...

  11. Evaluation of the new gravity control in Poland

    NASA Astrophysics Data System (ADS)

    Sękowski, M.; Dykowski, P.; Krynski, J. S.

    2015-12-01

    The new gravity control in Poland is based on absolute gravity measurements. It consists of 28 fundamental stations and 168 base stations. Fundamental stations are located in laboratories; they are to be surveyed in 2014 with the FG5-230 of the Warsaw University of Technology. Base stations are monumented field stations; they were surveyed in 2012 and 2013 with the A10-020 gravimeter. They are the subject of the paper. Besides absolute gravity measurements the vertical gravity gradient was precisely determined at all 168 base stations. Inconsistency of the determined vertical gravity gradients with respect to the normal ones has been presented. 77 base stations are also the stations of the previous gravity (POGK98) established in 90. of 20 century. Differences between newly determined gravity at those stations with those of POGK98 were evaluated. Alongside the establishment of the base stations of the gravity control multiple additional activities were performed to assure and provide the proper gravity reference level. They concerned regular gravity measurements on monthly basis with the A10-020 at three sites in Borowa Gora Geodetic-Geophysical Observatory, calibrations of metrological parameters of the A10-020 gravimeter and scale factor calibrations of LCR gravimeters, participation with the A10-020 in the international (ECAG2011, ICAG2013) and regional comparison campaigns of absolute gravimeters, and local comparisons of the A10-020 with the FG5-230. The summary of the work performed during the establishment of the gravity control is best described by total uncertainty budget for the A10-020 gravimeter determined on each of the 168 gravity stations.

  12. Development status of the planar electrostatic gradiometer GREMLIT for airborne geodesy

    NASA Astrophysics Data System (ADS)

    Foulon, B.; Christophe, B.; Douch, K.; Panet, I.

    2012-12-01

    The GREMLIT airborne gravity gradiometer is taking advantage of technologies, formerly developed by ONERA for the GRACE and GOCE space missions. Built using a planar configuration with four proof-masses at the corners of a square, the gradiometer is mounted on a dedicated stabilized platform which is controlled by the common mode outputs of the instrument itself to achieve a sufficient rejection ratio of the perturbations/vibrations induced by the airborne environment in the horizontal directions. The levitation of the proof-masses along the normal gravity and the vibration isolation of the platform are designed to allow the instrument to support between +2.5 g and 0 g along the vertical axis. With the help of additional fiber gyro data, the gradiometer differential measurements provide the necessary information to extract the 3 Tyy, Tzz and Tyz independent components of the gravity gradient tensor at the location of the instrument. In addition to be especially well suited to sustain the proof-mass levitation in the Earth's gravity field, such a planar configuration also presents an intrinsic linearity of the horizontal control loops which minimizes the aliasing due to high frequency vibrations or motions generated outside the measurement bandwidth. The compactness of the gradiometer design, with all the electrodes of the 4 accelerometers engrave on the same ULE plate, ensures excellent dimensional stability, good thermal homogeneity and makes the conception of the stabilized platform easier. The detailed error budget of the gradiometer instrument associated with the estimated performance of the platform and the assumed characteristics of the additional attitude, rate and position sensors lead to expect a performance objective between 0.1 and 1 Eötvös taking into account the difficulty of measurements onboard an aircraft by comparison to the particularly conducive satellite measurement environment. The GREMLIT gravity gradiometer systems is more particularly

  13. Airborne Imagery Collections Barrow 2013

    DOE Data Explorer

    Cherry, Jessica; Crowder, Kerri

    2015-07-20

    The data here are orthomosaics, digital surface models (DSMs), and individual frames captured during low altitude airborne flights in 2013 at the Barrow Environmental Observatory. The orthomosaics, thermal IR mosaics, and DSMs were generated from the individual frames using Structure from Motion techniques.

  14. Tropospheric and Airborne Emission Spectrometers

    NASA Technical Reports Server (NTRS)

    Glavich, Thomas; Beer, Reinhard

    1996-01-01

    X This paper describes the development of two related instruments, the Tropospheric Emission Spectrometer (TES) and the Airborne Emission Spectrometer (AES). Both instruments are infrared imaging Fourier Transform Spectrometers, used for measuring the state of the lower atmosphere, and in particular the measurement of ozone and ozone sources and sinks.

  15. Airborne chemicals and forest health

    SciTech Connect

    Woodman, J.N.; Cowling, E.B.

    1987-02-01

    Over the past few years the possible contribution of acid rain to the problem of forest decline has been a cause of increasing public concern. Research has begun to determine whether airborne chemicals are causing or contributing to visible damage and mortality in eastern spruce-fir and sugar maple forests and to changes in tree growth, usually without visible symptoms, in other parts of North America. This paper describes some of the complex biological relationships that determine health and productivity of forests and that make it difficult to distinguish effects of airborne chemicals from effects of natural stress. It describes four major research approaches for assessment of the effects of airborne chemicals on forests, and it summarizes current understanding of the known and possible effects of airborne chemicals on forest trees in North America and Europe. It also briefly describes the major air quality and forest health research programs in North America, and it assesses how ell these programs are likely to meet information needs during the coming decade. 69 references, 2 figures, 1 table.

  16. Airborne asbestos in public buildings

    SciTech Connect

    Chesson, J.; Hatfield, J.; Schultz, B.; Dutrow, E.; Blake, J. )

    1990-02-01

    The U.S. Environmental Protection Agency sampled air in 49 government-owned buildings (six buildings with no asbestos-containing material, six buildings with asbestos-containing material in generally good condition, and 37 buildings with damaged asbestos-containing material). This is the most comprehensive study to date of airborne asbestos levels in U.S. public buildings during normal building activities. The air outside each building was also sampled. Air samples were analyzed by transmission electron microscopy using a direct transfer preparation technique. The results show an increasing trend in average airborne asbestos levels; outdoor levels are lowest and levels in buildings with damaged asbestos-containing material are highest. However, the measured levels and the differences between indoors and outdoors and between building categories are small in absolute magnitude. Comparable studies from Canada and the UK, although differing in their estimated concentrations, also conclude that while airborne asbestos levels may be elevated in buildings that contain asbestos, levels are generally low. This conclusion does not eliminate the possibility of higher airborne asbestos levels during maintenance or renovation that disturbs the asbestos-containing material.

  17. Gauge/Gravity Duality (Gauge Gravity Duality)

    SciTech Connect

    Polchinski, Joseph

    2010-02-24

    Gauge theories, which describe the particle interactions, are well understood, while quantum gravity leads to many puzzles. Remarkably, in recent years we have learned that these are actually dual, the same system written in different variables. On the one hand, this provides our most precise description of quantum gravity, resolves some long-standing paradoxes, and points to new principles. On the other, it gives a new perspective on strong interactions, with surprising connections to other areas of physics. I describe these ideas, and discuss current and future directions.

  18. Gravity Driven Universe

    NASA Astrophysics Data System (ADS)

    Masters, Roy

    2010-03-01

    Flowing global gravitation initially produced space without time or mass. Space-time and mass are properties of flowing global gravitation. From its fabric, primal mass spins spontaneously giving rise to local gravitational space-time curvatures. Global gravity is the unifying background field. Gravity began flowing from its singularity with a big whoosh. It curves with angular rotational precession, creating a spatial geometry similar to the windings of a ball of string. Three-dimensional global gravity swirls locally into massive densities. Concurrently with these densities, local gravity curvatures of space-time arise. The expanse between celestial objects is not completely empty, void space as generally believed; it is antecedent gravity, a prerequisite associated field necessary for originating the first quantum particles. Gravity is dark energy; gravity's spin, as the second fundamental force, is electromagnetic dark matter. Electromagnetic masses attract then gravity compresses hot, dense and small---then bang, the first hydrogen star of which there are many. There may have been many big bangs, but no Big Bang that ultimately created the universe.

  19. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    The use is studied of tether systems to improve the lowest possible steady gravity level on the Space Station. Particular emphasis is placed by the microgravity community on the achievement of high quality microgravity conditions. The tether capability is explored for active control of the center of gravity and the analysis of possible tethered configurations.

  20. Demonstrating Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Pearlman, Howard; Stocker, Dennis; Gotti, Daniel; Urban, David; Ross, Howard; Sours, Thomas

    1996-01-01

    A miniature drop tower, Reduced-Gravity Demonstrator is developed to illustrate the effects of gravity on a variety of phenomena including the way fluids flow, flames burn, and mechanical systems (such as pendulum) behave. A schematic and description of the demonstrator and payloads are given, followed by suggestions for how one can build his (her) own.

  1. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    Information on the Tethered Gravity Laboratory on the International Space Station is given in viewgraph form. Topics covered include active control, low gravity processes identification, systems analysis, tether interfaces with the Laboratory, elevator and payload configurations, elevator subsystems, and accelerometer technology requirements.

  2. Hybrid theory of gravity

    NASA Astrophysics Data System (ADS)

    Kan, Nahomi; Maki, Takuya; Shiraishi, Kiyoshi

    2016-10-01

    We propose a model of gravity in which a General Relativity metric tensor and an effective metric generated from a single scalar formulated in geometric scalar gravity are mixed. We show that the model yields the exact Schwarzschild solution, along with accelerating behavior of scale factors in cosmological solutions.

  3. Routing architecture and security for airborne networks

    NASA Astrophysics Data System (ADS)

    Deng, Hongmei; Xie, Peng; Li, Jason; Xu, Roger; Levy, Renato

    2009-05-01

    Airborne networks are envisioned to provide interconnectivity for terrestial and space networks by interconnecting highly mobile airborne platforms. A number of military applications are expected to be used by the operator, and all these applications require proper routing security support to establish correct route between communicating platforms in a timely manner. As airborne networks somewhat different from traditional wired and wireless networks (e.g., Internet, LAN, WLAN, MANET, etc), security aspects valid in these networks are not fully applicable to airborne networks. Designing an efficient security scheme to protect airborne networks is confronted with new requirements. In this paper, we first identify a candidate routing architecture, which works as an underlying structure for our proposed security scheme. And then we investigate the vulnerabilities and attack models against routing protocols in airborne networks. Based on these studies, we propose an integrated security solution to address routing security issues in airborne networks.

  4. Anti-gravity device

    NASA Technical Reports Server (NTRS)

    Palsingh, S. (Inventor)

    1975-01-01

    An educational toy useful in demonstrating fundamental concepts regarding the laws of gravity is described. The device comprises a sphere 10 of radius r resting on top of sphere 12 of radius R. The center of gravity of sphere 10 is displaced from its geometrical center by distance D. The dimensions are so related that D((R+r)/r) is greater than r. With the center of gravity of sphere 10 lying on a vertical line, the device is in equilibrium. When sphere 10 is rolled on the surface of sphere 12 it will return to its equilibrium position upon release. This creates an illusion that sphere 10 is defying the laws of gravity. In reality, due to the above noted relationship of D, R, and r, the center of gravity of sphere 10 rises from its equilibrium position as it rolls a short distance up or down the surface of sphere 12.

  5. Drilling of airborne radioactivity anomalies in Florida, Georgia, and South Carolina, 1954

    USGS Publications Warehouse

    Cathcart, J.B.

    1954-01-01

    From April 22 to May 19, 1953, airborne radioactivity surveys totalling 5,600 traverse miles were made in 10 areas in Florida (Moxham, 1954).  Abnormal radioactivity was recorded in Bradford, Clay, DeSoto, Dixie, Lake, Marion, Orange, Sumter, Taylor, and Union Counties, Florida.  Additional airborne surveys were made in the Spring of 1954 in Hardee and Manatee Counties, Florida, on the drainage of the Altamaha River in Georgia, and in the area of the old phosphate workings in and around Charleston County, South Carolina.

  6. Digital Isostatic Gravity Map of the Nevada Test Site and Vicinity, Nye, Lincoln, and Clark Counties, Nevada, and Inyo County, California

    USGS Publications Warehouse

    Ponce, David A.; Mankinen, E.A.; Davidson, J.G.; Morin, R.L.; Blakely, R.J.

    2000-01-01

    An isostatic gravity map of the Nevada Test Site area was prepared from publicly available gravity data (Ponce, 1997) and from gravity data recently collected by the U.S. Geological Survey (Mankinen and others, 1999; Morin and Blakely, 1999). Gravity data were processed using standard gravity data reduction techniques. Southwest Nevada is characterized by gravity anomalies that reflect the distribution of pre-Cenozoic carbonate rocks, thick sequences of volcanic rocks, and thick alluvial basins. In addition, regional gravity data reveal the presence of linear features that reflect large-scale faults whereas detailed gravity data can indicate the presence of smaller-scale faults.

  7. Data processing of remotely sensed airborne hyperspectral data using the Airborne Processing Library (APL): Geocorrection algorithm descriptions and spatial accuracy assessment

    NASA Astrophysics Data System (ADS)

    Warren, Mark A.; Taylor, Benjamin H.; Grant, Michael G.; Shutler, Jamie D.

    2014-03-01

    Remote sensing airborne hyperspectral data are routinely used for applications including algorithm development for satellite sensors, environmental monitoring and atmospheric studies. Single flight lines of airborne hyperspectral data are often in the region of tens of gigabytes in size. This means that a single aircraft can collect terabytes of remotely sensed hyperspectral data during a single year. Before these data can be used for scientific analyses, they need to be radiometrically calibrated, synchronised with the aircraft's position and attitude and then geocorrected. To enable efficient processing of these large datasets the UK Airborne Research and Survey Facility has recently developed a software suite, the Airborne Processing Library (APL), for processing airborne hyperspectral data acquired from the Specim AISA Eagle and Hawk instruments. The APL toolbox allows users to radiometrically calibrate, geocorrect, reproject and resample airborne data. Each stage of the toolbox outputs data in the common Band Interleaved Lines (BILs) format, which allows its integration with other standard remote sensing software packages. APL was developed to be user-friendly and suitable for use on a workstation PC as well as for the automated processing of the facility; to this end APL can be used under both Windows and Linux environments on a single desktop machine or through a Grid engine. A graphical user interface also exists. In this paper we describe the Airborne Processing Library software, its algorithms and approach. We present example results from using APL with an AISA Eagle sensor and we assess its spatial accuracy using data from multiple flight lines collected during a campaign in 2008 together with in situ surveyed ground control points.

  8. Primordial gravity waves and weak lensing.

    PubMed

    Dodelson, Scott; Rozo, Eduardo; Stebbins, Albert

    2003-07-11

    Inflation produces a primordial spectrum of gravity waves in addition to the density perturbations which seed structure formation. We compute the signature of these gravity waves in the large scale shear field. The shear can be divided into a gradient mode (G or E) and a curl mode (C or B). The latter is produced only by gravity waves, so the observations of a nonzero curl mode could be seen as evidence for inflation. We find that the expected signal from inflation is small, peaking on the largest scales at l(l+1)C(l)/2pi<10(-11) at l=2 and falling rapidly thereafter. Even for an all-sky deep survey, this signal would be below noise at all multipoles. PMID:12906468

  9. Observational bounds on modified gravity models

    SciTech Connect

    De Felice, Antonio; Mukherjee, Pia; Wang Yun

    2008-01-15

    Modified gravity provides a possible explanation for the currently observed cosmic acceleration. In this paper, we study general classes of modified gravity models. The Einstein-Hilbert action is modified by using general functions of the Ricci and the Gauss-Bonnet scalars, both in the metric and in the Palatini formalisms. We do not use an explicit form for the functions, but a general form with a valid Taylor expansion up to second order about redshift zero in the Riemann-scalars. The coefficients of this expansion are then reconstructed via the cosmic expansion history measured using current cosmological observations. These are the quantities of interest for theoretical considerations relating to ghosts and instabilities. We find that current data provide interesting constraints on the coefficients. The next-generation dark energy surveys should shrink the allowed parameter space for modified gravity models quite dramatically.

  10. Primordial gravity waves and weak lensing.

    PubMed

    Dodelson, Scott; Rozo, Eduardo; Stebbins, Albert

    2003-07-11

    Inflation produces a primordial spectrum of gravity waves in addition to the density perturbations which seed structure formation. We compute the signature of these gravity waves in the large scale shear field. The shear can be divided into a gradient mode (G or E) and a curl mode (C or B). The latter is produced only by gravity waves, so the observations of a nonzero curl mode could be seen as evidence for inflation. We find that the expected signal from inflation is small, peaking on the largest scales at l(l+1)C(l)/2pi<10(-11) at l=2 and falling rapidly thereafter. Even for an all-sky deep survey, this signal would be below noise at all multipoles.

  11. The planar electrostatic gradiometer GREMLIT for airborne geodesy and its dedicated controlled platform

    NASA Astrophysics Data System (ADS)

    Foulon, Bernard; Christophe, Bruno; Huynh, Phuong-Anh; Lebat, Vincent; Perrot, Eddy

    2015-04-01

    Thanks to global positioning satellites constellations and to recent space gravity missions, the knowledge of the gravity field of the Earth has been considerably improved this last decade. Nevertheless these gravity data do not address spatial resolution shorter than 90 km and airborne gravity data collection will be of the highest interest to complete them at the short wavelengths in particular in the areas where spatial distribution and quality of ground data remain quite uneven like for example land/sea transition. Taking advantage of technologies, developed by ONERA for the GRACE and GOCE space missions, the GREMLIT airborne gravity gradiometer is composed of a double planar electrostatic gradiometer with eight proof-masses in a cubic configuration, the GREMLIT instrument is mounted on a dedicated stabilized platform which is controlled by the common mode outputs of the instrument itself to achieve a sufficient rejection ratio of the perturbations/vibrations induced by the airborne environment in the horizontal directions. The levitation of the proof-masses along the normal gravity and the vibration isolation of the platform are designed to allow the instrument to support 1g ± 1g along the vertical axis. In addition to be well suited to sustain the proof-mass levitation in the Earth's gravity field, the planar configuration of each accelerometer also presents an intrinsic linearity of the horizontal control loops which minimizes the aliasing due to high frequency vibrations or motions generated outside the measurement bandwidth. Realistic simulations, based on actual data and recorded environmental aircraft perturbations, demonstrate that a performance better or equal to one Eötvös can be obtained at least along the two horizontal components of the gravity gradient. If the performance of the electrostatic gradiometer is well assessed through the experience of the space accelerometers, the overall performance has also to take into account the estimated

  12. Ocean Melting Greenland (OMG) bathymetric survey of northwest Greenland and implications for the recent evolution of its glaciers

    NASA Astrophysics Data System (ADS)

    Wood, M.; Rignot, E. J.; Willis, J. K.; Fenty, I. G.

    2015-12-01

    Oceans Melting Greenland (OMG) is a five-year Earth Ventures Suborbital Mission funded by NASA to investigate the role of the oceans in ice loss around the margins of the Greenland Ice Sheet, which includes measurements of seafloor bathymetry from multibeam surveys and airborne gravity, glacier surface elevation from high-frequency radar interferometry, and temperature/salinity/depth from vessels and airborne-dropped probes. Here, we describe the results of the 2016 bathymetry survey of northwest Greenland that took place in the summer of 2015: july 22-August 19 and Sept 2-Sept 16 spanning from Ilulissat to Thule AFB in north Greenland, and to be complemented by a survey of southeast Greenland in 2016. We deployed a multibeam Reson 7160 with 512 beams installed on the hull of the Cape Race vessel, with enhanced capabilities for fjord wall and ice face mapping. The survey tracks were optimized based on the IBCAO3 database, recent cruises, airborne gravity data collected by NASA Operation IceBridge which indicated the presence of troughs, bed topography mapped inland using a mass conservation approach, the spatial distribution of ice discharge to locate the largest outlets and maximizing the number of major fjords sampled during the survey, with the goal to identify all troughs that are major pathways for subsurface ocean heat, and constrain as many glacier ice front thickness as permitted by time and the practicality of navigating the ice-choked fjords. The data reveal many deep, U-shaped, submarine valleys connected to the glaciers, intercut with sills and over deepened in narrower passages where former glaciers and ice streams merged into larger units; as well as fjords ending in shallow plateaus with glaciers in retreated positions. The presence of warm, salty water of Atlantic origin (AW) in the fjords is documented using CTD. Some glaciers sit on shallow plateaus in cold, fresh polar waters (PW) at the end of deep fjords, while others are deeper and standing in

  13. The use of airborne lasers in terrestrial and water environments

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Link, L. E.; Swift, R. N.

    1983-01-01

    This document has the objective to provide some information regarding the applications for which an airborne laser system can be utilized. The considered data have been collected with the NASA Airborne Oceanographic Lidar (AOL), operational since 1977 as a flying laser laboratory. The most basic mode of operation of the AOL involves operation as a profiler. The data collected are similar to those which would be collected by a ground survey party. In the fluorosensing mode, pulsed laser light is used to induce fluorescence in various pigments contained in land and water targets. A capability for reliably mapping bottom geometry in clear ocean water to depths of 10-12 meters was also demonstrated, while other studies are related to the utilization of the AOL for synoptic mapping of surface layer concentrations of chlorophyll and other photopigments contained in phytoplankton.

  14. 1994-1995 CNR LARA project airborne hyperspectral campaigns

    SciTech Connect

    Bianchi, R.; Cavalli, R.M.; Fiumi, L.

    1996-08-01

    CNR established a new laboratory for airborne hyperspectral imaging devoted to environmental problems and since the end of last June 1994 the project (LARA Project) is fully operative to provide hyperspectral data to the national and international scientific community. The Daedalus AA5000 MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) instrument, acquired by CNR (Italian National Research Council) in the framework of its LARA (Airborne Laboratory for Environmental Studies) Project, has been intensively operative. A number of MIVIS deployments have been carried out in Italy and Europe in cooperation with national and international institutions on a variety of sites, including active volcanoes, coastlines, lagoons and ocean, vegetated and cultivated areas, oil polluted surfaces, waste discharges, and archeological sites. One year of activity has shown the high system efficiency, from the survey to data preprocessing and dissemination.

  15. Exposure to airborne asbestos in buildings

    SciTech Connect

    Lee, R.J.; Van Orden, D.R.; Corn, M.; Crump, K.S. )

    1992-08-01

    The concentration of airborne asbestos in buildings and its implication for the health of building occupants is a major public health issue. A total of 2892 air samples from 315 public, commercial, residential, school, and university buildings has been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result of exposure to the presence of asbestos containing materials (ACM). The average concentration of all asbestos structures was 0.02 structures/ml (s/ml) and the average concentration of asbestos greater than or equal to 5 microns long was 0.00013 fibers/ml (f/ml). The concentration of asbestos was higher in schools than in other buildings. In 48% of indoor samples and 75% of outdoor samples, no asbestos fibers were detected. The observed airborne concentration in 74% of the indoor samples and 96% of the outdoor samples is below the Asbestos Hazard Emergency Response Act clearance level of 0.01 s/ml. Finally, using those fibers which could be seen optically, all indoor samples and all outdoor samples are below the Occupational Safety and Health Administration permissible exposure level of 0.1 f/ml for fibers greater than or equal to 5 microns in length. These results provide substantive verification of the findings of the U.S. Environmental Protection Agency public building study which found very low ambient concentrations of asbestos fibers in buildings with ACM, irrespective of the condition of the material in the buildings.

  16. The combined gravity field model GOCO05c

    NASA Astrophysics Data System (ADS)

    Fecher, Thomas; Pail, Roland; Gruber, Thomas; GOCO Project Team

    2016-04-01

    Knowledge of the static gravity field is of importance for various scientific disciplines, such as geodesy, geophysics and oceanography. While for geophysics the gravity field provides insight into the Earth's interior, the geoid serves as an important reference surface for oceanographic applications. Moreover this reference surface is a key parameter on the way to a globally unified height system. In order to exploit the full potential of gravity measurements and to achieve the best gravity field solution, all kinds of complementary gravity field information have to be combined. By combining GRACE and GOCE information, a state of the art satellite-only gravity field is available, which is highly accurate at the very long to medium wavelengths (80-100 km). By adding information from terrestrial/airborne gravimetry and satellite altimetry, which both are measurement techniques providing short wavelength gravity information beyond the resolution of GOCE, the full gravity field spectrum can be obtained. This paper focuses on the presentation of the combined gravity field model GOCO05c, a global gravity field model up to degree and order 720 based on full normal equation systems (more than 500,000 parameters). During the calculation of GOCO05c we put emphasis on the question how the complementary data types can be combined in a global gravity field model in the way that all data types keep their specific strengths and are not degraded by the combination with other information in certain wavelengths. Realistic stochastic modelling and a tailored weighting scheme among all available data results in different regional relative weighting of satellite and terrestrial data in the combined solution, mainly depending on the quality of the available terrestrial gravity information. From this procedure, as complementary product realistic error estimates are available in terms of a full-covariance matrix, which can be mapped in a spatial error grid reflecting regionally specific

  17. Monitoring Groundwater Contaminant Plumes Using Airborne Geophysical Data

    NASA Astrophysics Data System (ADS)

    Robinson, Martin; Oftendinger, Ulrich; Ruffell, Alastair; Cowan, Marie; Cassidy, Rachel; Comte, Jean-Christophe; Wilson, Christopher; Desissa, Mohammednur

    2013-04-01

    Under the European Union Water Framework Directive, Member States are required to assess water quality across both surface water and groundwater bodies. Subsurface pollution plumes, originating from a variety of sources, pose a significant direct risk to water quality. The monitoring and characterisation of groundwater contaminant plumes is generally invasive, time consuming and expensive. In particular, adequately capturing the contaminant plume with monitoring installations, when the extent of the feature is unknown and the presence of contamination is only evident from indirect observations, can be prohibitively expensive. This research aims to identify the extent and nature of subsurface contaminant plumes using airborne geophysical survey data. This data was collected across parts of the island of Ireland within the scope of the original Tellus and subsequent Tellus Border projects. The rapid assessment of the airborne electro-magnetic (AEM) data allowed the identification of several sites containing possible contaminant plumes. These AEM anomalies were assessed through the analysis of existing site data and field site inspections, with areas of interest being examined for metallic structures that could affect the AEM data. Electrical resistivity tomography (ERT), ground penetrating radar (GPR) and ground-based electro-magnetic (EM) surveys were performed to ground-truth existing airborne data and to confirm the extent and nature of the affected area identified using the airborne data. Groundwater and surface water quality were assessed using existing field site information. Initial results collected from a landfill site underlain by basalt have indicated that the AEM data, coupled with ERT and GPR, can successfully be used to locate possible plumes and help delineate their extent. The analysis of a range of case study sites exhibiting different geological and environmental settings will allow for the development of a consistent methodology for examining the

  18. Testing gravity with EG: mapping theory onto observations

    NASA Astrophysics Data System (ADS)

    Leonard, C. Danielle; Ferreira, Pedro G.; Heymans, Catherine

    2015-12-01

    We present a complete derivation of the observationally motivated definition of the modified gravity statistic EG. Using this expression, we investigate how variations to theory and survey parameters may introduce uncertainty in the general relativistic prediction of EG. We forecast errors on EG for measurements using two combinations of upcoming surveys, and find that theoretical uncertainties may dominate for a futuristic measurement. Finally, we compute predictions of EG under modifications to general relativity in the quasistatic regime, and comment on the pros and cons of using EG to test gravity with future surveys.

  19. Interest of a combined electrostatic/cold atoms gradiometers configuration for airborne geodesy

    NASA Astrophysics Data System (ADS)

    Foulon, Bernard; Christophe, Bruno; Douch, Karim; Panet, Isabelle; Bresson, Alexandre

    2014-05-01

    During these two last decades, the knowledge of the gravity field of the Earth has been considerably improved thanks to global positioning satellites constellations and to recent space gravity missions. However these gravity data do not address spatial resolution shorter than 90 km. Taking advantage of technologies, developed by ONERA for the GRACE and GOCE space missions, the GREMLIT airborne gravity gradiometer is more particularly developed to complete them at the short wavelengths in particular in the areas where spatial distribution and quality of ground data remain quite uneven like for example land/sea transition. Built using a double planar electrostatic gradiometer with eight proof-masses in a cubic configuration, the GREMLIT instrument is mounted on a dedicated stabilized platform which is controlled by the common mode outputs of the instrument itself to achieve a sufficient rejection ratio of the perturbations/vibrations induced by the airborne environment in the horizontal directions. The levitation of the proof-masses along the normal gravity and the vibration isolation of the platform are designed to allow the instrument to support 1g ± 1g along the vertical axis. In addition to be well suited to sustain the proof-mass levitation in the Earth's gravity field, the planar configuration of each accelerometer also presents an intrinsic linearity of the horizontal control loops which minimizes the aliasing due to high frequency vibrations or motions generated outside the measurement bandwidth. Taking into account the estimated performance of the platform and associated with its additional attitude and angular rate sensors, the gradiometer differential measurements along the two horizontal axes provide the necessary information to extract 5 of the 6 components of the gravity gradient tensor at the location of the instrument with a performance objective better than 1 Eötvös along the two Txx and Tyy horizontal components. The last vertical Tzz component

  20. Improved configuration of the planar electrostatic gradiometer GREMLIT for airborne geodesy

    NASA Astrophysics Data System (ADS)

    Foulon, B.; Lebat, V.; Christophe, B.; Douch, K.; Panet, I.

    2013-12-01

    The knowledge of the gravity field of the Earth has been considerably improved thanks to global positioning satellites constellations and to recent space gravity missions. However these gravity data do not adresse spatial resolution shorter than 90 km. Taking advantage of technologies, developed by ONERA for the GRACE and GOCE space missions, the GREMLIT airborne gravity gradiometer is more particularly developed to complete them at the short wavelengths in particular in the areas where spatial distribution and quality of ground data remain quite uneven like for example land/sea transition. Built using a double planar electrostatic gradiometer with eight proof-masses in a cubic configuration, the GREMLIT instrument is mounted on a dedicated stabilized platform which is controlled by the common mode outputs of the instrument itself to achieve a sufficient rejection ratio of the perturbations/vibrations induced by the airborne environment in the horizontal directions. The levitation of the proof-masses along the normal gravity and the vibration isolation of the platform are designed to allow the instrument to support 1g × 1g along the vertical axis. In addition to be well suited to sustain the proof-mass levitation in the Earth's gravity field, the planar configuration of each accelerometer also presents an intrinsic linearity of the horizontal control loops which minimizes the aliasing due to high frequency vibrations or motions generated outside the measurement bandwidth. Taking into account the estimated performance of the platform and associated with its additional attitude and angular rate sensors, the gradiometer differential measurements along the two horizontal axes provide the necessary information to extract 5 of the 6 components of the gravity gradient tensor at the location of the instrument with a performance objective between 0.1 and 1 Eötvös along the two Txx and Tyy horizontal components. The last vertical Tzz component of the gravity gradient

  1. Large aperture scanning airborne lidar

    NASA Technical Reports Server (NTRS)

    Smith, J.; Bindschadler, R.; Boers, R.; Bufton, J. L.; Clem, D.; Garvin, J.; Melfi, S. H.

    1988-01-01

    A large aperture scanning airborne lidar facility is being developed to provide important new capabilities for airborne lidar sensor systems. The proposed scanning mechanism allows for a large aperture telescope (25 in. diameter) in front of an elliptical flat (25 x 36 in.) turning mirror positioned at a 45 degree angle with respect to the telescope optical axis. The lidar scanning capability will provide opportunities for acquiring new data sets for atmospheric, earth resources, and oceans communities. This completed facility will also make available the opportunity to acquire simulated EOS lidar data on a near global basis. The design and construction of this unique scanning mechanism presents exciting technological challenges of maintaining the turning mirror optical flatness during scanning while exposed to extreme temperatures, ambient pressures, aircraft vibrations, etc.

  2. World gravity standards

    NASA Technical Reports Server (NTRS)

    Uotila, U. A.

    1978-01-01

    In order to use gravity anomalies in geodetic computations and geophysical interpretations, the observed gravity values from which anomalies are derived should be referred to one consistent world wide system. The International Gravity Standardization Net 1971 was adapted by the International Union of Geodesy and Geophysics at Moscow in 1971, the network was result of extensive cooperation by many organizations and individuals around the world. The network contains more than 1800 stations around the world. The data used in the adjustment included more than 25,000 gravimetry, pendulum and absolute measurements.

  3. Theoretical support for the Airborne Antarctic Ozone Experiment. Final report

    SciTech Connect

    Hartmann, D.L.

    1992-03-01

    This investigation was to provide theoretical support during and after the deployment of NASA research aircraft to Punta Arenas, Chile during August and September of 1987 to conduct the Airborne Antarctic Ozone Experiment. The experiment was very successful in demonstrating the role of anthropogenic chlorine in producing the ozone hole over Antarctica during September and October of 1987. The PI worked primarily on using tracer data from the ER-2 aircraft to show that transport could not have caused the ozone hole in 1987, and that transport of chemical species into the polar vortex was very weak during the period of the experiment. The presence of gravity waves was also very apparent in the ER-2 data, and papers were published on this analysis and on the use of meteorological analyses to position the aircraft within the vortex.

  4. Airborne particulate matter in spacecraft

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  5. NASA Student Airborne Research Program

    NASA Astrophysics Data System (ADS)

    Schaller, E. L.; Shetter, R. E.

    2012-12-01

    The NASA Student Airborne Research Program (SARP) is a unique summer internship program for advanced undergraduates and early graduate students majoring in the STEM disciplines. SARP participants acquire hands-on research experience in all aspects of an airborne research campaign, including flying onboard an major NASA resource used for studying Earth system processes. In summer 2012, thirty-two participants worked in four interdisciplinary teams to study surface, atmospheric, and oceanographic processes. Participants assisted in the operation of instruments onboard the NASA P-3B aircraft where they sampled and measured atmospheric gases and imaged land and water surfaces in multiple spectral bands. Along with airborne data collection, students participated in taking measurements at field sites. Mission faculty and research mentors helped to guide participants through instrument operation, sample analysis, and data reduction. Over the eight-week program, each student developed an individual research project from the data collected and delivered a conference-style final presentation on his/her results. We will discuss the results and effectiveness of the program from the first four summers and discuss plans for the future.

  6. Effects of background gravity stimuli on gravity-controlled behavior

    NASA Technical Reports Server (NTRS)

    Mccoy, D. F.

    1976-01-01

    Physiological and developmental effects of altered gravity were researched. The stimulus properties of gravity have been found to possess reinforcing and aversive properties. Experimental approaches taken, used animals placed into fields of artificial gravity, in the form of parabolic or spiral centrifuges. Gravity preferences were noted and it was concluded that the psychophysics of gravity and background factors which support these behaviors should be further explored.

  7. Effects of gravity data quality and spacing on the accuracy of the geoid in South Korea

    NASA Astrophysics Data System (ADS)

    Hong, C.-K.; Kwon, J. H.; Lee, B. M.; Lee, J.; Choi, Y. S.; Lee, S.-B.

    2009-07-01

    The effects of gravity data quality and spacing on the accuracy of the computed geoid are analyzed. The analysis is performed using simulated gravity data that accommodate the real gravity signal in South Korea. The reference geoid is generated using both simulated gravity data and digital terrain models (DTM), assuming that both data sets are errorless. By artificially controlling the gravity data quality and spacing, we are able to calculate and analyze the geoid errors. The results show that the current distribution of real gravity data in South Korea causes geoid errors, with the standard deviation being as much as 8 cm, and that these geoid errors are mainly caused by the distribution of gravity data rather than by the noise in the data. Areas showing large geoid errors are also clearly identified; these areas should be subjected to supplementary gravity surveying at data spacing smaller than 2 km to achieve a 5-cm level of geoid accuracy.

  8. Hydrogeologic Framework of the Upper Santa Cruz Basin (Arizona and Sonora) using Well Logs, Geologic Mapping, Gravity, Magnetics, and Electromagnetics

    NASA Astrophysics Data System (ADS)

    Callegary, J. B.; Page, W. R.; Megdal, S.; Gray, F.; Scott, C. A.; Berry, M.; Rangel, M.; Oroz Ramos, L.; Menges, C. M.; Jones, A.

    2011-12-01

    In 2006, the U.S. Congress passed the U.S.-Mexico Transboundary Aquifer Assessment Act which provides a framework for study of aquifers shared by the United States and Mexico. The aquifer of the Upper Santa Cruz Basin was chosen as one of four priority aquifers for several reasons, including water scarcity, a population greater than 300,000, groundwater as the sole source of water for human use, and a riparian corridor that is of regional significance for migratory birds and other animals. Several new mines are also being proposed for this area which may affect water quality and availability. To date, a number of studies have been carried out by a binational team composed of the U.S. Geological Survey, the Mexican National Water Commission, and the Universities of Arizona and Sonora. Construction of a cross-border hydrogeologic framework model of the basin between Amado, Arizona and its southern boundary in Sonora is currently a high priority. The relatively narrow Santa Cruz valley is a structural basin that did not experience the same degree of late Cenozoic lateral extension and consequent deepening as found in other basin-and-range alluvial basins, such as the Tucson basin, where basin depth exceeds 3000 meters. This implies that storage may be much less than that found in other basin-and-range aquifers. To investigate the geometry of the basin and facies changes within the alluvium, a database of over one thousand well logs has been developed, geologic mapping and transient electromagnetic (TEM) surveys have been carried out, and information from previous electromagnetic, magnetic, and gravity studies is being incorporated into the hydrogeologic framework. Initial geophysical surveys and analyses have focused on the portion of the basin west of Nogales, Arizona, because it supplies approximately 50% of that city's water. Previous gravity and magnetic modeling indicate that this area is a narrow, fault-controlled half graben. Preliminary modeling of airborne

  9. Evaluation Of The Potential Of Gravity Anomalies From Satellite Altimetry By Merging With Gravity Data From Various Sources - Application To Coastal Areas

    NASA Astrophysics Data System (ADS)

    Fernandes, M. J.; Bastos, L.; Tomé, P.

    The region of the Azores archipelago is a natural laboratory for gravity field studies, due to its peculiar geodynamic and oceanographic features, related to rough structures in the gravity field. As a consequence, gravity data from various sources have been collected in the scope of various observation campaigns. The available data set comprises marine, airborne and satellite derived gravity anoma- lies. The satellite data have been derived by altimetric inversion of satellite altimeter data (Topex/Poseidon and ERS), to which processing methods tuned for optimal data recovery in coastal areas have been applied. Marine and airborne data along coinci- dent profiles, some of them coincident with satellite tracks, were collected during an observation campaign that took place in the Azores in 1997, in the scope of the Eu- ropean Union project AGMASCO. In addition, gravity anomalies from an integrated GPS/INS system installed aboard an aircraft, have also been computed from the posi- tion and navigation data collected during the AGMASCO campaign. This paper presents a comparison study between all available data sets. In particular, the improvement of the satellite derived anomalies near the shoreline is assessed with respect to existing satellite derived models and with the high resolution geopotential model GPM98. The impact of these data sets in the regional geoid improvement will also be presented.

  10. Measuring gravity currents in the Chicago River, Chicago, Illinois

    USGS Publications Warehouse

    Oberg, K.A.; Czuba, J.A.; Johnson, K.K.

    2008-01-01

    Recent studies of the Chicago River have determined that gravity currents are responsible for persistent bidirectional flows that have been observed in the river. A gravity current is the flow of one fluid within another caused by a density difference between the fluids. These studies demonstrated how acoustic Doppler current profilers (ADCP) can be used to detect and characterize gravity currents in the field. In order to better understand the formation and evolution of these gravity currents, the U.S. Geological Survey (USGS) has installed ADCPs and other instruments to continuously measure gravity currents in the Chicago River and the North Branch Chicago River. These instruments include stage sensors, thermistor strings, and both upward-looking and horizontal ADCPs. Data loggers and computers installed at gaging stations along the river are used to collect data from these instruments and transmit them to USGS offices. ?? 2008 IEEE.

  11. Changes at an activated sludge sewage treatment plant alter the numbers of airborne aerobic microorganisms.

    PubMed

    Fernando, Nadeesha L; Fedorak, Phillip M

    2005-11-01

    In 1976, the activated sludge sewage treatment plant in Edmonton, Canada, was surveyed to determine the numbers of culturable airborne microorganisms. Many changes have been made at the plant to reduce odors and improve treatment efficiency, so in 2004 another survey was done to determine if these changes had reduced the bioaerosols. Covering the grit tanks and primary settling tanks greatly reduced the numbers of airborne microbes. Changing the design and operation of indoor automated sampling taps and sinks also reduced bioaerosols. The secondary was expanded and converted from a conventional activated sludge process using coarse bubble aeration to a biological nutrient removal system using fine bubble aeration. Although the surface area of the secondary more than doubled, the average number of airborne microorganisms in this part of the plant in 2004 was about 1% of that in 1976.

  12. Assessing and Correcting Topographic Effects on Forest Canopy Height Retrieval Using Airborne LiDAR Data

    PubMed Central

    Duan, Zhugeng; Zhao, Dan; Zeng, Yuan; Zhao, Yujin; Wu, Bingfang; Zhu, Jianjun

    2015-01-01

    Topography affects forest canopy height retrieval based on airborne Light Detection and Ranging (LiDAR) data a lot. This paper proposes a method for correcting deviations caused by topography based on individual tree crown segmentation. The point cloud of an individual tree was extracted according to crown boundaries of isolated individual trees from digital orthophoto maps (DOMs). Normalized canopy height was calculated by subtracting the elevation of centres of gravity from the elevation of point cloud. First, individual tree crown boundaries are obtained by carrying out segmentation on the DOM. Second, point clouds of the individual trees are extracted based on the boundaries. Third, precise DEM is derived from the point cloud which is classified by a multi-scale curvature classification algorithm. Finally, a height weighted correction method is applied to correct the topological effects. The method is applied to LiDAR data acquired in South China, and its effectiveness is tested using 41 field survey plots. The results show that the terrain impacts the canopy height of individual trees in that the downslope side of the tree trunk is elevated and the upslope side is depressed. This further affects the extraction of the location and crown of individual trees. A strong correlation was detected between the slope gradient and the proportions of returns with height differences more than 0.3, 0.5 and 0.8 m in the total returns, with coefficient of determination R2 of 0.83, 0.76, and 0.60 (n = 41), respectively. PMID:26016907

  13. Assessing and correcting topographic effects on forest canopy height retrieval using airborne LiDAR data.

    PubMed

    Duan, Zhugeng; Zhao, Dan; Zeng, Yuan; Zhao, Yujin; Wu, Bingfang; Zhu, Jianjun

    2015-01-01

    Topography affects forest canopy height retrieval based on airborne Light Detection and Ranging (LiDAR) data a lot. This paper proposes a method for correcting deviations caused by topography based on individual tree crown segmentation. The point cloud of an individual tree was extracted according to crown boundaries of isolated individual trees from digital orthophoto maps (DOMs). Normalized canopy height was calculated by subtracting the elevation of centres of gravity from the elevation of point cloud. First, individual tree crown boundaries are obtained by carrying out segmentation on the DOM. Second, point clouds of the individual trees are extracted based on the boundaries. Third, precise DEM is derived from the point cloud which is classified by a multi-scale curvature classification algorithm. Finally, a height weighted correction method is applied to correct the topological effects. The method is applied to LiDAR data acquired in South China, and its effectiveness is tested using 41 field survey plots. The results show that the terrain impacts the canopy height of individual trees in that the downslope side of the tree trunk is elevated and the upslope side is depressed. This further affects the extraction of the location and crown of individual trees. A strong correlation was detected between the slope gradient and the proportions of returns with height differences more than 0.3, 0.5 and 0.8 m in the total returns, with coefficient of determination R2 of 0.83, 0.76, and 0.60 (n = 41), respectively. PMID:26016907

  14. Assessing and correcting topographic effects on forest canopy height retrieval using airborne LiDAR data.

    PubMed

    Duan, Zhugeng; Zhao, Dan; Zeng, Yuan; Zhao, Yujin; Wu, Bingfang; Zhu, Jianjun

    2015-05-26

    Topography affects forest canopy height retrieval based on airborne Light Detection and Ranging (LiDAR) data a lot. This paper proposes a method for correcting deviations caused by topography based on individual tree crown segmentation. The point cloud of an individual tree was extracted according to crown boundaries of isolated individual trees from digital orthophoto maps (DOMs). Normalized canopy height was calculated by subtracting the elevation of centres of gravity from the elevation of point cloud. First, individual tree crown boundaries are obtained by carrying out segmentation on the DOM. Second, point clouds of the individual trees are extracted based on the boundaries. Third, precise DEM is derived from the point cloud which is classified by a multi-scale curvature classification algorithm. Finally, a height weighted correction method is applied to correct the topological effects. The method is applied to LiDAR data acquired in South China, and its effectiveness is tested using 41 field survey plots. The results show that the terrain impacts the canopy height of individual trees in that the downslope side of the tree trunk is elevated and the upslope side is depressed. This further affects the extraction of the location and crown of individual trees. A strong correlation was detected between the slope gradient and the proportions of returns with height differences more than 0.3, 0.5 and 0.8 m in the total returns, with coefficient of determination R2 of 0.83, 0.76, and 0.60 (n = 41), respectively.

  15. A Comparison Between Three IMUs for Strapdown Airborne Gravimetry

    NASA Astrophysics Data System (ADS)

    Ayres-Sampaio, Diogo; Deurloo, Richard; Bos, Machiel; Magalhães, Américo; Bastos, Luísa

    2015-07-01

    Strapdown airborne gravimetry relies on the combination of an inertial measuring unit (IMU) and a global navigation satellite system (GNSS) to measure the Earth's gravity field. Early results with navigation-grade IMUs showed similar accuracies to those obtained with scalar gravimetric systems in the down component. This paper investigates the accuracy of three IMUs used for strapdown airborne gravimetry under the same flight conditions. The three systems considered were navigation-grade IMUs, iXSea AIRINS and iMAR iNAV-FMS, and a tactical-grade Litton LN-200. The data were collected in 2010 over the Island of Madeira, Portugal, in the scope of GEOid over MADeira campaign. The coordinates and orientation of the aircraft were computed using an extended Kalman filter based on the inertial navigation approach. GNSS position and velocity observations were used to update the filter, and the gravity disturbance was considered to be a stochastic process and was part of the state vector. A new crossover point-based serial tuning was introduced to deal with the uncertainty of choosing the filter's a priori information. The results show that with the iXSea accuracies of 2.1 and 1.6 mGal can be obtained for 1.7 and 5.0 km of spatial resolution (half-wavelength), respectively. iMAR's results were significantly affected by a nonlinear drift, which led to lower accuracies of 4.1-5.5 mGal. Remarkably, Litton showed very consistent results and achieved an accuracy of about 4.5 mGal at 5 km of spatial resolution (half-wavelength).

  16. Time dependent corrections to absolute gravity determinations in the establishment of modern gravity control

    NASA Astrophysics Data System (ADS)

    Dykowski, Przemyslaw; Krynski, Jan

    2015-04-01

    The establishment of modern gravity control with the use of exclusively absolute method of gravity determination has significant advantages as compared to the one established mostly with relative gravity measurements (e.g. accuracy, time efficiency). The newly modernized gravity control in Poland consists of 28 fundamental stations (laboratory) and 168 base stations (PBOG14 - located in the field). Gravity at the fundamental stations was surveyed with the FG5-230 gravimeter of the Warsaw University of Technology, and at the base stations - with the A10-020 gravimeter of the Institute of Geodesy and Cartography, Warsaw. This work concerns absolute gravity determinations at the base stations. Although free of common relative measurement errors (e.g. instrumental drift) and effects of network adjustment, absolute gravity determinations for the establishment of gravity control require advanced corrections due to time dependent factors, i.e. tidal and ocean loading corrections, atmospheric corrections and hydrological corrections that were not taken into account when establishing the previous gravity control in Poland. Currently available services and software allow to determine high accuracy and high temporal resolution corrections for atmospheric (based on digital weather models, e.g. ECMWF) and hydrological (based on hydrological models, e.g. GLDAS/Noah) gravitational and loading effects. These corrections are mostly used for processing observations with Superconducting Gravimeters in the Global Geodynamics Project. For the area of Poland the atmospheric correction based on weather models can differ from standard atmospheric correction by even ±2 µGal. The hydrological model shows the annual variability of ±8 µGal. In addition the standard tidal correction may differ from the one obtained from the local tidal model (based on tidal observations). Such difference at Borowa Gora Observatory reaches the level of ±1.5 µGal. Overall the sum of atmospheric and

  17. Superconducting tensor gravity gradiometer

    NASA Technical Reports Server (NTRS)

    Paik, H. J.

    1981-01-01

    The employment of superconductivity and other material properties at cryogenic temperatures to fabricate sensitive, low-drift, gravity gradiometer is described. The device yields a reduction of noise of four orders of magnitude over room temperature gradiometers, and direct summation and subtraction of signals from accelerometers in varying orientations are possible with superconducting circuitry. Additional circuits permit determination of the linear and angular acceleration vectors independent of the measurement of the gravity gradient tensor. A dewar flask capable of maintaining helium in a liquid state for a year's duration is under development by NASA, and a superconducting tensor gravity gradiometer for the NASA Geodynamics Program is intended for a LEO polar trajectory to measure the harmonic expansion coefficients of the earth's gravity field up to order 300.

  18. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    Variable Gravity Laboratory studies are discussed. The following subject areas are covered: (1) conceptual design and engineering analysis; (2) control strategies (fast crawling maneuvers, main perturbations and their effect upon the acceleration level); and (3) technology requirements.

  19. How emergent is gravity?

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Swastik; Shankaranarayanan, S.

    2015-10-01

    General theory of relativity (or Lovelock extensions) is a dynamical theory; given an initial configuration on a spacelike hypersurface, it makes a definite prediction of the final configuration. Recent developments suggest that gravity may be described in terms of macroscopic parameters. It finds a concrete manifestation in the fluid-gravity correspondence. Most of the efforts till date has been to relate equilibrium configurations in gravity with fluid variables. In order for the emergent paradigm to be truly successful, it has to provide a statistical mechanical derivation of how a given initial static configuration evolves into another. In this paper, we show that the energy transport equation governed by the fluctuations of the horizon-fluid is similar to Raychaudhuri equation and hence gravity is truly emergent.

  20. Perturbative QUANTUM GRAVITY

    NASA Astrophysics Data System (ADS)

    't Hooft, Gerard

    2003-12-01

    A good understanding of Perturbative Quantum Gravity is essential for anyone who wishes to proceed towards any kind of non-perturbative approach. This lecture is a brief resumé of the main features of the perturbative regime.

  1. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1989-01-01

    The following subject areas are covered: (1) thermal control issues; (2) attitude control sybsystem; (3) configuration constraints; (4) payload; (5) acceleration requirements on Variable Gravity Laboratory (VGL); and (6) VGL configuration highlights.

  2. Free-surface microfluidics for detection of airborne explosives

    NASA Astrophysics Data System (ADS)

    Meinhart, Carl; Piorek, Brian; Banerjee, Sanjoy; Lee, Seung Joon; Moskovits, Martin

    2008-11-01

    A novel microfluidic, remote-sensing, chemical detection platform has been developed for real-time sensing of airborne agents. The key enabling technology is a newly developed concept termed Free-Surface Fluidics (FSF), where one or more fluidic surfaces of a microchannel flow are confined by surface tension and exposed to the surrounding atmosphere. The result is a unique open channel flow environment that is driven by pressure through surface tension, and not subject to body forces, such as gravity. Evaporation and flow rates are controlled by microchannel geometry, surface chemistry and precisely-controlled temperature profiles. The free-surface fluidic architecture is combined with Surface-Enhanced Raman Spectroscopy (SERS) to allow for real-time profiling of atmospheric species and detection of airborne agents. The aggregation of SERS nanoparticles is controlled using microfluidics, to obtain dimer nanoparticle clusters at known streamwise positions in the microchannel. These dimers form SERS hot-spots, which amplify the Raman signal by 8 -- 10 orders of magnitude. Results indicate that explosive agents such as DNT, TNT, RDX, TATP and picric acid in the surrounding atmosphere can be readily detected by the SERS system. Due to the amplification of the SERS system, explosive molecules with concentrations of parts per trillion can be detected, even in the presence of interferent molecules having six orders of magnitude higher concentration.

  3. What Is Gravity?

    ERIC Educational Resources Information Center

    Nelson, George

    2004-01-01

    Gravity is the name given to the phenomenon that any two masses, like you and the Earth, attract each other. One pulls on the Earth and the Earth pulls on one the same amount. And one does not have to be touching. Gravity acts over vast distances, like the 150 million kilometers (93 million miles) between the Earth and the Sun or the billions of…

  4. Gravity data analysis

    NASA Technical Reports Server (NTRS)

    Sjogren, William L.

    1987-01-01

    Work on three different efforts related to gravity data analysis is discussed. The reduction of raw Doppler data from the Apollo 15 subsatellite to produce acceleration profiles as a function of latitude, longitude and altitude; an investigation related to fitting long arcs of Pioneer Venus Orbiter tracking data; and a study of gravity/topography ratios which were found to have a linear trend with longitude are discussed.

  5. Integrated gravity and gravity gradient 3D inversion using the non-linear conjugate gradient

    NASA Astrophysics Data System (ADS)

    Qin, Pengbo; Huang, Danian; Yuan, Yuan; Geng, Meixia; Liu, Jie

    2016-03-01

    Gravity data, which are critical in mineral, oil, and gas exploration, are obtained from the vertical component of the gravity field, while gravity gradient data are measured from changes in the gravity field in three directions. However, few studies have sought to improve exploration techniques by integrating gravity and gravity gradient data using inversion methods. In this study, we developed a new method to integrate gravity and gravity gradient data in a 3D density inversion using the non-linear conjugate gradient (NLCG) method and the minimum gradient support (MGS) functional to regularize the 3D inverse problem and to obtain a clear and accurate image of the anomalous body. The NLCG algorithm, which is suitable for solving large-scale nonlinear optimization problems and requires no memory storage, was compared to the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton algorithm and the results indicated that the convergence rate of NLCG is slower, but that the storage requirement and computation time is lower. To counteract the decay in kernel function, we introduced a depth weighting function for anomalous bodies at the same depth, with information about anomalous body depth obtained from well log and seismic exploration data. For anomalous bodies at different depths, we introduced a spatial gradient weighting function to incorporate additional information obtained in the inversion. We concluded that the spatial gradient weighting function enhanced the spatial resolution of the recovered model. Furthermore, our results showed that including multiple components for inversion increased the resolution of the recovered model. We validated our model by applying our inversion method to survey data from Vinton salt dome, Louisiana, USA. The results showed good agreement with known geologic information; thus confirming the accuracy of this approach.

  6. Coupled Gravity and Elevation Measurement of Ice Sheet Mass Change

    NASA Technical Reports Server (NTRS)

    Jezek, K. C.; Baumgartner, F.

    2005-01-01

    During June 2003, we measured surface gravity at six locations about a glaciological measurement site located on the South-central Greenland Ice. We operated a GPS unit for 90 minutes at each site -the unit was operated simultaneously with a base station unit in Sondrestrom Fjord so as to enable differential, post-processing of the data. We installed an aluminum, accumulation-rate-pole at each site. The base section of the pole also served as the mount for the GPS antenna. Two gravimeters were used simultaneously at each site. Measurements were repeated at each site with at time lapse of at least 50 minutes. We measured snow physical properties in two shallow pits The same measurement sites were occupied in 1981 and all were part of a hexagonal network of geodetic and glaciological measurements established by The Ohio State University in 1980. Additional gravity observations were acquired at three of the sites in 1993 and 1995. Gravity data were collected in conjunction with Doppler satellite measurements of position and elevation in 1981 and global positioning system measurements subsequently. The use of satellite navigation techniques permitted reoccupation of the same sites in each year to within a few 10 s of meters or better. After detrending the gravity data, making adjustments for tides and removing the residual effects of local spatial gradients in gravity, we observe an average secular decrease in gravity of about 0.01 milligal/year, but with tenths of milligal variations about the mean trend. The trend is consistent with a nearly linear increase in surface elevation of between 7 to 10 c d y r (depending on location) as measured by repeated airborne laser altimeter, surface Doppler satellite and GPS elevation measurements. Differences between the residual gravity anomalies after free air correction may be attributable to local mass changes. This project is a collaboration between the Byrd Polar Research Center of the Ohio State University and the Arctic

  7. Gravity Before Einstein and Schwinger Before Gravity

    NASA Astrophysics Data System (ADS)

    Trimble, Virginia L.

    2012-05-01

    Julian Schwinger was a child prodigy, and Albert Einstein distinctly not; Schwinger had something like 73 graduate students, and Einstein very few. But both thought gravity was important. They were not, of course, the first, nor is the disagreement on how one should think about gravity that is being highlighted here the first such dispute. The talk will explore, first, several of the earlier dichotomies: was gravity capable of action at a distance (Newton), or was a transmitting ether required (many others). Did it act on everything or only on solids (an odd idea of the Herschels that fed into their ideas of solar structure and sunspots)? Did gravitational information require time for its transmission? Is the exponent of r precisely 2, or 2 plus a smidgeon (a suggestion by Simon Newcomb among others)? And so forth. Second, I will try to say something about Scwinger's lesser known early work and how it might have prefigured his "source theory," beginning with "On the Interaction of Several Electrons (the unpublished, 1934 "zeroth paper," whose title somewhat reminds one of "On the Dynamics of an Asteroid," through his days at Berkeley with Oppenheimer, Gerjuoy, and others, to his application of ideas from nuclear physics to radar and of radar engineering techniques to problems in nuclear physics. And folks who think good jobs are difficult to come by now might want to contemplate the couple of years Schwinger spent teaching elementary physics at Purdue before moving on to the MIT Rad Lab for war work.

  8. Updated Status of the Planar Electrostatic Gradiometer GREMLIT for Airborne Geodesy

    NASA Astrophysics Data System (ADS)

    Foulon, B.; Christophe, B.; Douch, K.; Lebat, V.; Panet, I.

    2014-12-01

    In spite of the important improvement provided by the recent space missions GRACE and GOCE to the accuracy of Earth's gravity field models, many geodetic and geophysical issues require higher resolution models. To address spatial resolution in the range between 80 km and 10 km, the airborne gravity gradiometry is a convenient way to complete these global models at the short wavelengths in particular in land/sea transition areas where the gravity field is poorly covered by current measurements. Taking advantage of technologies, developed by ONERA for the accelerometers used in these space gravity missions, the new GREMLIT airborne gravity gradiometer is more particularly developed to determine the horizontal components of the gravity gradient tensor in the instrumental frame. GREMLIT is composed of a double deck of a compact planar assembly of 4 electrostatic accelerometers. The eight plane proof-masses are arranged in a cubic configuration and the whole instrument is mounted on a dedicated stabilized platform which is controlled by the common mode outputs of the instrument itself to achieve a sufficient rejection ratio of the perturbations induced by the airborne environment in the horizontal directions. In addition to be well suited to sustain the proof-mass levitation in the Earth's gravity field, the planar configuration presents an intrinsic linearity of the control loops which minimizes the aliasing effects. Concerning the present development, in addition to the one axis prototype manufactured in order to verify the hardware performance of the concept, detailed numerical simulations were conducted over some realistic coastal test areas. Taking into account the data sheet performance of the associated commercial angular and data rate sensors and assuming actual airplane acceleration measurements, they lead to exhibit accuracy below 1E along the Txx and Tyy horizontal components. The characteristic of the controlled platform being one of the key point of the

  9. Michigan Magnetic and Gravity Maps and Data: A Website for the Distribution of Data

    USGS Publications Warehouse

    Daniels, David L.; Kucks, Robert P.; Hill, Patricia L.; Snyder, Stephen L.

    2009-01-01

    This web site provides the best available, public-domain, aeromagnetic and gravity data in the State of Michigan and merges these data into composite grids that are available for downloading. The magnetic grid is compiled from 25 separate magnetic surveys that have been knit together to form a single composite digital grid and map. The magnetic survey grids have been continued to 305 meters (1,000 feet) above ground and merged together to form the State compilation. A separate map shows the location of the aeromagnetic surveys, color-coded to the survey flight-line spacing. In addition, a complete Bouguer gravity anomaly grid and map were generated from more than 20,000 gravity station measurements from 33 surveys. A table provides the facts about each gravity survey where known.

  10. Approximating edges of source bodies from magnetic or gravity anomalies.

    USGS Publications Warehouse

    Blakely, R.J.; Simpson, R.W.

    1986-01-01

    Cordell and Grauch (1982, 1985) discussed a technique to estimate the location of abrupt lateral changes in magnetization or mass density of upper crustal rocks. The final step of their procedure is to identify maxima on a contoured map of horizontal gradient magnitudes. Attempts to automate their final step. The method begins with gridded magnetic or gravity anomaly data and produces a plan view of inferred boundaries of magnetic or gravity sources. The method applies to both local surveys and to continent-wide compilations of magnetic and gravity data.-from Authors

  11. Accurate method of modeling cluster scaling relations in modified gravity

    NASA Astrophysics Data System (ADS)

    He, Jian-hua; Li, Baojiu

    2016-06-01

    We propose a new method to model cluster scaling relations in modified gravity. Using a suite of nonradiative hydrodynamical simulations, we show that the scaling relations of accumulated gas quantities, such as the Sunyaev-Zel'dovich effect (Compton-y parameter) and the x-ray Compton-y parameter, can be accurately predicted using the known results in the Λ CDM model with a precision of ˜3 % . This method provides a reliable way to analyze the gas physics in modified gravity using the less demanding and much more efficient pure cold dark matter simulations. Our results therefore have important theoretical and practical implications in constraining gravity using cluster surveys.

  12. Testing gravity using dwarf stars

    NASA Astrophysics Data System (ADS)

    Sakstein, Jeremy

    2015-12-01

    Generic scalar-tensor theories of gravity predict deviations from Newtonian physics inside astrophysical bodies. In this paper, we point out that low mass stellar objects, red and brown dwarf stars, are excellent probes of these theories. We calculate two important and potentially observable quantities: the radius of brown dwarfs and the minimum mass for hydrogen burning in red dwarfs. The brown dwarf radius can differ significantly from the general relativity prediction, and upcoming surveys that probe the mass-radius relation for stars with masses

  13. Field of view selection for optimal airborne imaging sensor performance

    NASA Astrophysics Data System (ADS)

    Goss, Tristan M.; Barnard, P. Werner; Fildis, Halidun; Erbudak, Mustafa; Senger, Tolga; Alpman, Mehmet E.

    2014-05-01

    The choice of the Field of View (FOV) of imaging sensors used in airborne targeting applications has major impact on the overall performance of the system. Conducting a market survey from published data on sensors used in stabilized airborne targeting systems shows a trend of ever narrowing FOVs housed in smaller and lighter volumes. This approach promotes the ever increasing geometric resolution provided by narrower FOVs, while it seemingly ignores the influences the FOV selection has on the sensor's sensitivity, the effects of diffraction, the influences of sight line jitter and collectively the overall system performance. This paper presents a trade-off methodology to select the optimal FOV for an imaging sensor that is limited in aperture diameter by mechanical constraints (such as space/volume available and window size) by balancing the influences FOV has on sensitivity and resolution and thereby optimizing the system's performance. The methodology may be applied to staring array based imaging sensors across all wavebands from visible/day cameras through to long wave infrared thermal imagers. Some examples of sensor analysis applying the trade-off methodology are given that highlights the performance advantages that can be gained by maximizing the aperture diameters and choosing the optimal FOV for an imaging sensor used in airborne targeting applications.

  14. Monitoring radioactive plumes by airborne gamma-ray spectrometry

    SciTech Connect

    Grasty, R.L.; Hovgaard, J.; Multala, J.

    1996-06-01

    Airborne gamma-ray spectrometer surveys using large volume sodium-iodide detectors are routinely flown throughout the world for mineral exploration and geological mapping. Techniques have now been developed to detect and map man-made sources of radiation. In Canada, airborne gamma-rays surveys have been flown around nuclear reactors to map {sup 41}Ar plumes from nuclear reactors and to calculate the dose rate at ground level. In May 1986, the Finnish Geological survey aircraft flew through a radioactive plume from the Chernobyl nuclear accident. As the aircraft flew through the plume, the aircraft became increasingly contaminated. By measuring the final aircraft contamination, the activity of the plume could be separated from the contamination due to the aircraft. Within 1 h of encountering the plume, the aircraft activity was comparable to the maximum levels found in the plume. From an analysis of the gamma-ray spectra, the concentration of {sup 131}I and {sup 140}La within the plume were calculated as a function of time.

  15. Regional and local controls on mineralization and pluton emplacement in the Bondy gneiss complex, Grenville Province, Canada interpreted from aeromagnetic and gravity data

    NASA Astrophysics Data System (ADS)

    Dufréchou, G.; Harris, L. B.; Corriveau, L.; Antonoff, V.

    2015-05-01

    The Bondy gneiss complex in the Grenville Province of Southwest Quebec hosts a mineralized iron oxide- and copper-rich hydrothermal system. The northern part of the complex overlies the lithospheric-scale Mont-Laurier lineament and is cut by the regional Mont-Laurier South shear zone interpreted from Bouguer gravity. A sinistral 6 km wide strike-slip corridor defined by several second-order shears (the Mont-Laurier South shear zone) in the complex was identified from geophysical data, including a new high-resolution airborne magnetic survey, and field observations. The spatial association of a metamorphosed alteration system, several pre- to post-metamorphic mineralized zones and mafic intrusions within the Mont-Laurier South shear zone suggests that (i) underlying basement structures controlled hydrothermal fluid migration during the formation of epithermal-IOCG mineralization and associated alteration system before ca. 1.2 Ga high-grade metamorphism and penetrative ductile deformation in the complex; (ii) post-metamorphic reactivation allowed magma ascent and pluton emplacement in the complex and adjacent supracrustal rocks within dilatational sites; and (iii) brittle-ductile shears that postdate high-grade metamorphism provided channel ways for fluid migration associated with magnetite-related mineralization. Although the complex does not host an economic mineral deposit, the role between structures at different levels and the combination of gravity and aeromagnetics at different scales provides an example of an approach for mineral exploration in similar high grade gneiss terrains.

  16. Modular airborne remote sampling and sensing system (MARSSS)

    SciTech Connect

    Woods, R.O.

    1982-04-01

    Sandia is developing a modular airborne instrumentation system for the Environmental Protection Agency. This system will allow flexibility in the choice of instruments by standardizing mountings, power supplies and sampling modes. The objective is to make it possible to perform aerial surveys from chartered aircraft that have not been adapted in a more than superficial manner. It will also allow the experimenter to tailor his choice of instruments to the specific problem. Since the equipment will have a stand-alone capability, it can be applied to other problems such as long-term unattended use at remote locations or in toxic or otherwise hazardous environments.

  17. A proof of concept: Airborne LIDAR-measured ellipsoidal heights of a lake surface correspond to a local geoid model

    NASA Astrophysics Data System (ADS)

    Zlinszky, András; Ressl, Camillo; Timár, Gábor; Weber, Robert; Székely, Balázs; Briese, Christian; Pfeifer, Norbert

    2013-04-01

    The geoid is the theoretical model of the Earth, defined as an equipotential surface. Typically it corresponds to a mean ocean surface and is extended through the continents. Elevations are measured above "sea level" based on the fact that the surface of water in equilibrium closely follows this equipotential surface. On dry land, the geoid can be determined from gravimetric measurements, and interpolation methods are used to represent variations of gravity in a regular grid model. For practical reasons, these are represented as geoid undulation, which is the difference of the ellipsoidal height and the height of the equipotential surface. In his work Principia, Isaac Newton proposed the thought experiment of connecting the North Pole and the Equator through a "canal" filled with water in order to determine gravitational flattening of the Earth. It was also Newton's idea to use the level of water in a global network of canals and wells to survey the geoid. Of course, these experiments are impossible at a global scale, but a sufficiently large lake and an accurate method for measuring elevation independently from the geoid can be used to prove the concept. Our objective was to measure the ellipsoidal water surface elevation of Lake Balaton in Hungary with high spatial resolution and accuracy and compare these measurements with the gravimetrically determined local geoid model. Airborne laser scanning (ALS, also known as airborne LIDAR) is a remote sensing technique capable of delivering a large number of points with elevations and horizontal positions accurate to a few centimetres. Laser pulses are emitted in a scan pattern from an airborne sensor, and are reflected from the illuminated terrain (or water) surface. Based on the position and orientation of the aircraft (typically observed by GNSS and an inertial navigation system), the scan angle and the travel time of the laser pulse, the exact position of each measurement point is calculated. In this particular case

  18. Airborne wavemeter validation and calibration

    NASA Technical Reports Server (NTRS)

    Goad, Joseph H., Jr.; Rinsland, Pamela L.; Kist, Edward H., Jr.; Geier, Erika B.; Banziger, Curtis G.

    1992-01-01

    This manuscript outlines a continuing effort to validate and verify the performance of an airborne autonomous wavemeter for tuning solid state lasers to a desired wavelength. The application is measuring the vertical profiles of atmospheric water vapor using a differential absorption lidar (DIAL) technique. Improved wavemeter performance data for varying ambient temperatures are presented. This resulted when the electronic grounding and shielding were improved. The results with short pulse duration lasers are also included. These lasers show that similar performance could be obtained with lasers operating in the continuous and the pulsed domains.

  19. Airborne Research Experience for Educators

    NASA Astrophysics Data System (ADS)

    Costa, V. B.; Albertson, R.; Smith, S.; Stockman, S. A.

    2009-12-01

    The Airborne Research Experience for Educators (AREE) Program, conducted by the NASA Dryden Flight Research Center Office of Education in partnership with the AERO Institute, NASA Teaching From Space Program, and California State University Fullerton, is a complete end-to-end residential research experience in airborne remote sensing and atmospheric science. The 2009 program engaged ten secondary educators who specialize in science, technology, engineering or mathematics in a 6-week Student Airborne Research Program (SARP) offered through NSERC. Educators participated in collection of in-flight remote sensor data during flights aboard the NASA DC-8 as well as in-situ research on atmospheric chemistry (bovine emissions of methane); algal blooms (remote sensing to determine location and degree of blooms for further in-situ analysis); and crop classification (exploration of how drought conditions in Central California have impacted almond and cotton crops). AREE represents a unique model of the STEM teacher-as-researcher professional development experience because it asks educators to participate in a research experience and then translate their experiences into classroom practice through the design, implementation, and evaluation of instructional materials that emphasize the scientific research process, inquiry-based investigations, and manipulation of real data. Each AREE Master Educator drafted a Curriculum Brief, Teachers Guide, and accompanying resources for a topic in their teaching assignment Currently, most professional development programs offer either a research experience OR a curriculum development experience. The dual nature of the AREE model engaged educators in both experiences. Educators’ content and pedagogical knowledge of STEM was increased through the review of pertinent research articles during the first week, attendance at lectures and workshops during the second week, and participation in the airborne and in-situ research studies, data

  20. Cyberinfrastructure for Airborne Sensor Webs

    NASA Technical Reports Server (NTRS)

    Freudinger, Lawrence C.

    2009-01-01

    Since 2004 the NASA Airborne Science Program has been prototyping and using infrastructure that enables researchers to interact with each other and with their instruments via network communications. This infrastructure uses satellite links and an evolving suite of applications and services that leverage open-source software. The use of these tools has increased near-real-time situational awareness during field operations, resulting in productivity improvements and the collection of better data. This paper describes the high-level system architecture and major components, with example highlights from the use of the infrastructure. The paper concludes with a discussion of ongoing efforts to transition to operational status.

  1. Biological monitoring of airborne pollution

    SciTech Connect

    Ditz, D.W. )

    1990-01-01

    Common plants such as grasses, mosses, and even goldenrod may turn out to have a new high-tech role as monitors of airborne pollution from solid waste incinerators. Certain plants that respond to specific pollutants can provide continuous surveillance of air quality over long periods of time: they are bio-indicators. Other species accumulate pollutants and can serve as sensitive indicators of pollutants and of food-chain contamination: they are bio-accumulators. Through creative use of these properties, biological monitoring can provide information that cannot be obtained by current methods such as stack testing.

  2. Toolsets for Airborne Data - URS and New Documentation

    Atmospheric Science Data Center

    2015-03-23

    ... airborne field missions, documentation, and EOSDIS User Registration System (URS) authentication. This web application features an intuitive user interface for variable selection across different airborne field studies and ...

  3. High resolution airborne geophysics at hazardous waste disposal sites

    SciTech Connect

    Beard, L.P.; Nyquist, J.E.; Doll, W.E.; Chong Foo, M.; Gamey, T.J.

    1995-06-01

    In 1994, a high resolution helicopter geophysical survey was conducted over portions of the Oak Ridge Reservation, Tennessee. The 1800 line kilometer survey included multi-frequency electromagnetic and magnetic sensors. The areas covered by the high resolution portion of the survey were selected on the basis of their importance to the environmental restoration effort and on data obtained from the reconnaissance phase of the airborne survey in which electromagnetic, magnetic, and radiometric data were collected over the entire Oak Ridge Reservation in 1992--1993. The high resolution phase had lower sensor heights, more and higher EM frequencies, and tighter line spacings than did the reconnaissance survey. When flying over exceptionally clear areas, the high resolution bird came within a few meters of the ground surface. Unfortunately, even sparse trees and power or phone lines could prevent the bird from being towed safely at low altitude, and over such areas it was more usual for it to be flown at about the same altitude as the bird in the reconnaissance survey, about 30m. Even so, the magnetometers used in the high resolution phase were 20m closer to the ground than in the reconnaissance phase because they were mounted on the tail of the bird rather than on the tow cable above the bird. The EM frequencies used in the high resolution survey ranged from 7400Hz to 67000Hz. Only the horizontal coplanar loop configuration was used in the high resolution flyovers.

  4. A new approach to interpretation of airborne magnetic and electromagnetic data

    SciTech Connect

    Traynin, P.; Zhdanov, M.; Nyquist, J.; Beard, L.; Doll, W.

    1996-06-01

    The airborne geophysical survey carried out at the Oak Ridge Reservation has shown that AEM can be used in evaluating details of waste areas. However, detection of small objects requires a flight altitude of 10-15 m which is impossible due to natural obstacles present in the Oak Ridge area. In these types of cases, data processing in the downward continuation allows to improve the survey resolution and a normalized gradient provides an additional information about the depth of buried objects.

  5. Gravity and Biology

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily R.

    1996-01-01

    Gravity has been the most constant environmental factor throughout the evolution of biological species on Earth. Organisms are rarely exposed to other gravity levels, either increased or decreased, for prolonged periods. Thus, evolution in a constant 1G field has historically prevented us from appreciating the potential biological consequences of a multi-G universe. To answer the question 'Can terrestrial life be sustained and thrive beyond our planet?' we need to understand the importance of gravity on living systems, and we need to develop a multi-G, rather than a 1G, mentality. The science of gravitational biology took a giant step with the advent of the space program, which provided the first opportunity to examine living organisms in gravity environments lower than could be sustained on Earth. Previously, virtually nothing was known about the effects of extremely low gravity on living organisms, and most of the initial expectations were proven wrong. All species that have flown in space survive in microgravity, although no higher organism has ever completed a life cycle in space. It has been found, however, that many systems change, transiently or permanently, as a result of prolonged exposure to microgravity.

  6. Tethered gravity laboratories study

    NASA Technical Reports Server (NTRS)

    Lucchetti, F.

    1990-01-01

    The scope of the study is to investigate ways of controlling the microgravity environment of the International Space Station by means of a tethered system. Four main study tasks were performed. First, researchers analyzed the utilization of the tether systems to improve the lowest possible steady gravity level on the Space Station and the tether capability to actively control the center of gravity position in order to compensate for activities that would upset the mass distribution of the Station. The purpose of the second task was to evaluate the whole of the experiments performable in a variable gravity environment and the related beneficial residual accelerations, both for pure and applied research in the fields of fluid, materials, and life science, so as to assess the relevance of a variable g-level laboratory. The third task involves the Tethered Variable Gravity Laboratory. The use of the facility that would crawl along a deployed tether and expose experiments to varying intensities of reduced gravity is discussed. Last, a study performed on the Attitude Tether Stabilizer concept is discussed. The stabilization effect of ballast masses tethered to the Space Station was investigated as a means of assisting the attitude control system of the Station.

  7. Venus Gravity Handbook

    NASA Technical Reports Server (NTRS)

    Konopliv, Alexander S.; Sjogren, William L.

    1996-01-01

    This report documents the Venus gravity methods and results to date (model MGNP90LSAAP). It is called a handbook in that it contains many useful plots (such as geometry and orbit behavior) that are useful in evaluating the tracking data. We discuss the models that are used in processing the Doppler data and the estimation method for determining the gravity field. With Pioneer Venus Orbiter and Magellan tracking data, the Venus gravity field was determined complete to degree and order 90 with the use of the JPL Cray T3D Supercomputer. The gravity field shows unprecedented high correlation with topography and resolution of features to the 2OOkm resolution. In the procedure for solving the gravity field, other information is gained as well, and, for example, we discuss results for the Venus ephemeris, Love number, pole orientation of Venus, and atmospheric densities. Of significance is the Love number solution which indicates a liquid core for Venus. The ephemeris of Venus is determined to an accuracy of 0.02 mm/s (tens of meters in position), and the rotation period to 243.0194 +/- 0.0002 days.

  8. Airborne electromagnetic imaging of discontinuous permafrost

    USGS Publications Warehouse

    Minsley, B.J.; Abraham, J.D.; Smith, B.D.; Cannia, J.C.; Voss, C.I.; Jorgenson, M.T.; Walvoord, M.A.; Wylie, B.K.; Anderson, L.; Ball, L.B.; Deszcz-Pan, M.; Wellman, T.P.; Ager, T.A.

    2012-01-01

    The evolution of permafrost in cold regions is inextricably connected to hydrogeologic processes, climate, and ecosystems. Permafrost thawing has been linked to changes in wetland and lake areas, alteration of the groundwater contribution to streamflow, carbon release, and increased fire frequency. But detailed knowledge about the dynamic state of permafrost in relation to surface and groundwater systems remains an enigma. Here, we present the results of a pioneering ???1,800 line-kilometer airborne electromagnetic survey that shows sediments deposited over the past ???4 million years and the configuration of permafrost to depths of ???100 meters in the Yukon Flats area near Fort Yukon, Alaska. The Yukon Flats is near the boundary between continuous permafrost to the north and discontinuous permafrost to the south, making it an important location for examining permafrost dynamics. Our results not only provide a detailed snapshot of the present-day configuration of permafrost, but they also expose previously unseen details about potential surface-groundwater connections and the thermal legacy of surface water features that has been recorded in the permafrost over the past ???1,000 years. This work will be a critical baseline for future permafrost studies aimed at exploring the connections between hydrogeologic, climatic, and ecological processes, and has significant implications for the stewardship of Arctic environments. ?? 2012 by the American Geophysical Union.

  9. Mapping suspected buried channels using gravity: Examples from southwest Michigan

    SciTech Connect

    Keighley, K.E.; Atekwana, E.A.; Sauck, W.A. . Dept. of Geology)

    1994-04-01

    This study documents the successful application of the gravity method in mapping suspected buried bedrock valleys at three sites in southwest Michigan. The first site is located in Benton Harbor, Berrien County. Gravity surveys were conducted along the Jean Klock Park as part of an ongoing coastal research study of the Lake Michigan shoreline. Previous Ground Penetrating Radar (GPR) studies at this site had suggested the presence of a buried valley. The results of the gravity survey confirmed the existence of a buried valley approximately 30--40 m deep and at least 2,000 m wide, which is in good agreement with information from drill cores suggesting a possible ancient river system. A detailed gravity survey was conducted at the second site located in Schoolcraft Township, Kalamazoo County, where the heavy use of pesticides has resulted in the contamination of the upper aquifers. Preliminary results suggest the presence of a broad shallow valley at least 25 m deep. Gravity surveys at the third site located southeast of the Kavco Landfill, Barry County also suggests the presence of a buried valley oriented NE-SW, confirming the interpretations of an earlier electrical resistivity study. It is possible that this channel controls groundwater flow and facilitates the transport of contaminants from the landfill to the surrounding areas.

  10. Meeting Review: Airborne Aerosol Inlet Workshop

    NASA Technical Reports Server (NTRS)

    Baumgardner, Darrel; Huebert, Barry; Wilson, Chuck

    1991-01-01

    Proceedings from the Airborne Aerosol Inlet Workshop are presented. The two central topics of discussion were the role of aerosols in atmospheric processes and the difficulties in characterizing aerosols. The following topics were discussed during the working sessions: airborne observations to date; identification of inlet design issues; inlet modeling needs and directions; objectives for aircraft experiments; and future laboratory and wind tunnel studies.

  11. Airborne Relay-Based Regional Positioning System

    PubMed Central

    Lee, Kyuman; Noh, Hongjun; Lim, Jaesung

    2015-01-01

    Ground-based pseudolite systems have some limitations, such as low vertical accuracy, multipath effects and near-far problems. These problems are not significant in airborne-based pseudolite systems. However, the monitoring of pseudolite positions is required because of the mobility of the platforms on which the pseudolites are mounted, and this causes performance degradation. To address these pseudolite system limitations, we propose an airborne relay-based regional positioning system that consists of a master station, reference stations, airborne relays and a user. In the proposed system, navigation signals are generated from the reference stations located on the ground and are relayed via the airborne relays. Unlike in conventional airborne-based systems, the user in the proposed system sequentially estimates both the locations of airborne relays and his/her own position. Therefore, a delay due to monitoring does not occur, and the accuracy is not affected by the movement of airborne relays. We conducted several simulations to evaluate the performance of the proposed system. Based on the simulation results, we demonstrated that the proposed system guarantees a higher accuracy than airborne-based pseudolite systems, and it is feasible despite the existence of clock offsets among reference stations. PMID:26029953

  12. Airborne Oceanographic Lidar (AOL) (Global Carbon Cycle)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This bimonthly contractor progress report covers the operation, maintenance and data management of the Airborne Oceanographic Lidar and the Airborne Topographic Mapper. Monthly activities included: mission planning, sensor operation and calibration, data processing, data analysis, network development and maintenance and instrument maintenance engineering and fabrication.

  13. Global Test Range: Toward Airborne Sensor Webs

    NASA Technical Reports Server (NTRS)

    Mace, Thomas H.; Freudinger, Larry; DelFrate John H.

    2008-01-01

    This viewgraph presentation reviews the planned global sensor network that will monitor the Earth's climate, and resources using airborne sensor systems. The vision is an intelligent, affordable Earth Observation System. Global Test Range is a lab developing trustworthy services for airborne instruments - a specialized Internet Service Provider. There is discussion of several current and planned missions.

  14. A Simple Method for Collecting Airborne Pollen

    ERIC Educational Resources Information Center

    Kevan, Peter G.; DiGiovanni, Franco; Ho, Rong H.; Taki, Hisatomo; Ferguson, Kristyn A.; Pawlowski, Agata K.

    2006-01-01

    Pollination is a broad area of study within biology. For many plants, pollen carried by wind is required for successful seed set. Airborne pollen also affects human health. To foster studies of airborne pollen, we introduce a simple device--the "megastigma"--for collecting pollen from the air. This device is flexible, yielding easily obtained data…

  15. Airborne Visible Laser Optical Communications Program (AVLOC)

    NASA Technical Reports Server (NTRS)

    Ward, J. H.

    1975-01-01

    The design, development, and operation of airborne and ground-based laser communications and laser radar hardware is described in support of the Airborne Visible Laser Optical Communication program. The major emphasis is placed on the development of a highly flexible test bed for the evaluation of laser communications systems techniques and components in an operational environment.

  16. Airborne EM for geothermal and hydrogeological mapping

    NASA Astrophysics Data System (ADS)

    Menghini, A.; Manzella, A.; Viezzoli, A.; Montanari, D.; Maggi, S.

    2012-12-01

    Within the "VIGOR" project, aimed at assessing the geothermal potential of four regions in southern Italy, Airborne EM data have been acquired, modeled and interpreted. The system deployed was SkyTEM, a time-domain helicopter electromagnetic system designed for hydrogeophysical, environmental and mineral investigations. The AEM data provide, after data acquisition, analysis, processing, and modeling, a distribution volume of electrical resistivity, spanning an investigation depth from ground surface of few hundred meters, depending on resistivity condition. Resistivity is an important physical parameter for geothermal investigation, since it proved to be very effective in mapping anomalies due to hydrothermal fluid circulation, which usually has high salt content and produces clayey alteration minerals. Since the project required, among other issues, to define geothermal resources at shallow level, it was decided to perform a test with an airborne electromagnetic geophysical survey, to verify the advantages offered by the system in covering large areas in a short time. The geophysical survey was carried out in Sicily, Italy, in late 2011, over two test sites named "Termini" and "Western Sicily". The two areas were chosen on different basis. "Termini" area is covered by extensive geological surveys, and was going to be investigated also by means of electrical tomography in its northern part. Since geological condition of Sicily, even at shallow depth, is very complex, this area provided a good place for defining the resistivity values of the main geological units outcropping in the region. "Termini" survey has been also an occasion to define relations between resistivity distribution, lithological units and thermal conductivity. The "Western Sicily" area cover the main thermal manifestations of