WorldWideScience

Sample records for s-wacr horizon-to-horizon range-height

  1. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    Science.gov (United States)

    Debnath, Mithu; Valerio Iungo, G.; Ashton, Ryan; Brewer, W. Alan; Choukulkar, Aditya; Delgado, Ruben; Lundquist, Julie K.; Shaw, William J.; Wilczak, James M.; Wolfe, Daniel

    2017-02-01

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

  2. Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals

    Science.gov (United States)

    Lamer, K.; Tatarevic, A.; Jo, I.; Kollias, P.

    2014-04-01

    The scanning Atmospheric Radiation Measurement (ARM) cloud radars (SACRs) provide continuous atmospheric observations aspiring to capture the 3-D cloud-scale structure. Sampling clouds in 3-D is challenging due to their temporal-spatial scales, the need to sample the sky at high elevations and cloud radar limitations. Thus, a suggested scan strategy is to repetitively slice the atmosphere from horizon to horizon as clouds advect over the radar (Cross-Wind Range-Height Indicator - CW-RHI). Here, the processing and gridding of the SACR CW-RHI scans are presented. First, the SACR sample observations from the ARM Southern Great Plains and Cape Cod sites are post-processed (detection mask, gaseous attenuation correction, insect filtering and velocity de-aliasing). The resulting radial Doppler moment fields are then mapped to Cartesian coordinates with time as one of the dimensions. Next the Cartesian-gridded Doppler velocity fields are decomposed into the horizontal wind velocity contribution and the vertical Doppler velocity component. For validation purposes, all gridded and retrieved fields are compared to collocated zenith-pointing ARM cloud radar measurements. We consider that the SACR sensitivity loss with range, the cloud type observed and the research purpose should be considered in determining the gridded domain size. Our results also demonstrate that the gridded SACR observations resolve the main features of low and high stratiform clouds. It is established that the CW-RHI observations complemented with processing techniques could lead to robust 3-D cloud dynamical representations up to 25-30 degrees off zenith. The proposed gridded products are expected to advance our understanding of 3-D cloud morphology, dynamics and anisotropy and lead to more realistic 3-D radiative transfer calculations.

  3. Radio metric direction finding - A new approach to deep space navigation

    Science.gov (United States)

    Melbourne, W. G.; Curkendall, D. W.

    1977-01-01

    The paper explores an alternate technique for the determination of the angular position and velocity of deep-space probes, wherein the two-way range and Doppler measurements are abandoned for large portions of the mission in favor of differential one-way measurements. The spacecraft employs a wideband beacon rather than a coherent transponder, and differential measurements of one-way range and perhaps range rate are made between the spacecraft and each of three tracking stations. Advantages include the following: (1) Range measurements do not require the long horizon-to-horizon Doppler passes, so that the tracking stations can be released to support other functions of the deep space network. (2) Improved accuracy in the angular coordinates of the spacecraft can be obtained. (3) The need for an uplink is eliminated. A system implementation of the concept is developed that appears economically feasible and achieves a 0.05 microrad baseline accuracy

  4. A Perspective On The Earth From The Moon

    Science.gov (United States)

    Scott, David R.

    ``What was most significant about the lunar voyage was not that men set foot on the Moon, but that they set eye on the Earth''. This statement, by Mr. Norman Cousins, Editor of the Saturday Review, summarizes the most significant aspect of the first departure of humans from the environment in which they were born, and in which they must survive. Looking back at the Earth from the Moon, the view is both splendid and overwhelming. This small blue ball in the vastness of black space, dotted with millions of marvellous stars, is an oasis that we must understand and protect. For, if one searches the heavens, one will find no other island for life as we understand it. If we humans do not protect and nurture this environment, it will disappear - just as quickly as the Earth will disappear from behind an outstretched thumb of a man on the Moon. Everything that has meaning disappears: science, history, music, poetry, art, literature, all of it on this small, fragile, and precious little spot out there in the vastness of the universe. From the Moon, we see many new and fascinating visions of the Earth. These views change not only our perspective of the Earth but our value system as well. As an example, from the Earth, we see the Moon track across the sky from horizon to horizon, always the same face, always the same features. But from the Moon, we see the Earth at the same point in the sky, day after day, but always turning, showing us new faces and changing features as the hours pass. We become aware of how much the physical features of the Earth are interrelated. And in a sense, we can ``see the future'' as the Earth turns in our view. From the Moon we see the Earth as a ``whole'' - we see no borders, we see no boundaries, we see all humankind together and interrelated on this single small sphere. This perspective from the Moon makes us realize that the Earth is dynamic and alive and evolving for the human presence - and we realize that if we care not for the life of the

  5. An Empirical State Error Covariance Matrix Orbit Determination Example

    Science.gov (United States)

    Frisbee, Joseph H., Jr.

    2015-01-01

    is suspect. In its most straight forward form, the technique only requires supplemental calculations to be added to existing batch estimation algorithms. In the current problem being studied a truth model making use of gravity with spherical, J2 and J4 terms plus a standard exponential type atmosphere with simple diurnal and random walk components is used. The ability of the empirical state error covariance matrix to account for errors is investigated under four scenarios during orbit estimation. These scenarios are: exact modeling under known measurement errors, exact modeling under corrupted measurement errors, inexact modeling under known measurement errors, and inexact modeling under corrupted measurement errors. For this problem a simple analog of a distributed space surveillance network is used. The sensors in this network make only range measurements and with simple normally distributed measurement errors. The sensors are assumed to have full horizon to horizon viewing at any azimuth. For definiteness, an orbit at the approximate altitude and inclination of the International Space Station is used for the study. The comparison analyses of the data involve only total vectors. No investigation of specific orbital elements is undertaken. The total vector analyses will look at the chisquare values of the error in the difference between the estimated state and the true modeled state using both the empirical and theoretical error covariance matrices for each of scenario.

  6. Total Lightning Observations within Electrified Snowfall using Polarimetric Radar, LMA, and NLDN Measurements

    Science.gov (United States)

    Schultz, Christopher J.; Carey, Lawerence D.; Brunning, Eric C.; Blakeslee, Richard

    2013-01-01

    Four electrified snowfall cases are examined using total lightning measurements from lightning mapping arrays (LMAs), and the National Lightning Detection Network (NLDN) from Huntsville, AL and Washington D.C. In each of these events, electrical activity was in conjunction with heavy snowfall rates, sometimes exceeding 5-8 cm hr-1. A combination of LMA, and NLDN data also indicate that many of these flashes initiated from tall communications towers and traveled over large horizontal distances. During events near Huntsville, AL, the Advanced Radar for Meteorological and Operational Research (ARMOR) C-band polarimetric radar was collecting range height indicators (RHIs) through regions of heavy snowfall. The combination of ARMOR polarimetric radar and VHF LMA observations suggested contiguous layer changes in height between sloping aggregate-dominated layers and horizontally-oriented crystals. These layers may have provided ideal conditions for the development of extensive regions of charge and resultant horizontal propagation of the lightning flashes over large distances.

  7. Development of a scanning micro-pulse lidar for aerosol and cloud detection

    Science.gov (United States)

    Chen, Chao; Wang, Zhangjun; Meng, Xiangqian; Qu, Junle; Du, Libin; Li, Xianxin; Lv, Bin; Kabanov, V. V.

    2014-11-01

    A scanning micro-pulse lidar (MPL) was developed by Institute of Oceanographic Instrumentation, Shandong Academy of Sciences, which can be used for routine observations of optical properties, temporal and spatial variation of atmospheric aerosol and cloud in the lower troposphere. In addition to the optical system design, the design of 3 dimensional (3-D) scanning system controlled by servo motors is analyzed, including servo motor selection and mechanical design. Through the measurements in Qingdao, it is proved that 3-D scanning system can control the lidar azimuth/elevation scanning with high precision. The lidar has good performance and can provide time-height indication (THI), range-height indication (RHI) and plane-position indication (PPI) of lidar signals which can well reflect the temporal and spatial variation of atmospheric aerosol.

  8. Videosonde observations of tropical precipitating clouds developed over the Sumatera Island, Indonesia

    Science.gov (United States)

    Suzuki, Kenji; Nakagawa, Katsuhiro; Kawano, Tetsuya; Mori, Shuichi; Katsumata, Masaki; Yoneyama, Kunio

    2017-04-01

    During November-December 2015, as a pilot study of the Years of the Maritime and Continent (YMC), a campaign observation over the southwestern coastal land and adjacent sea of Sumatera Island, Indonesia was carried out to examine land-ocean coupling processes in mechanisms of coastal heavy rain. Our videosonde observations were conducted as a part of this campaign for the better understandings of microphysical features in tropical precipitating clouds developed over the Sumatera Island. Videosonde is one of strong tools to measure hydrometeors in clouds directly. It is a balloon-borne radiosonde that acquires images of precipitation particles via a CCD camera. The system has a stroboscopic illumination that provides information on particle size and shape. One of the advantages for the videosonde is to capture images of precipitation particles as they are in the air because the videosonde can obtain particle images without contact. Recorded precipitation particles are classified as raindrops, frozen drops (hail), graupel, ice crystals, or snowflakes on the basis of transparency and shape. Videosondes were launched from BMKG Bengkulu weather station (3.86°S,102.3°E). After the launch of a videosonde, the Range Height Indicator (RHI) scans by a C-band dual-polarimetric radar installed on R/V Mirai, which was approximately 50 km off Sumatera Island, were continuously performed, targeting the videosonde in the precipitating cloud. Eighteen videosondes were launched into various types of tropical precipitating clouds during the Pre-YMC campaign.

  9. Pegvisomant treatment in a 4-year-old girl with neurofibromatosis type 1

    DEFF Research Database (Denmark)

    Main, Katharina M; Sehested, Astrid; Feldt-Rasmussen, Ulla

    2006-01-01

    with acromegaly. We wanted to investigate whether pegvisomant was effective in a child with octreotide-resistant GH excess. CASE: A 4-year-old girl with neurofibromatosis type 1 and GH excess associated with optic glioma received pegvisomant injections (10 mg subcutaneously) with increasing intervals from daily...... to every 4th day. RESULTS: IGF-I and IGFBP-3 decreased from +6.9 and 4.6 standard deviation scores (SDS), respectively, to within normal range. Height velocity dropped from 12.4 SDS to mean -0.7 SDS (range: -5.0 to 5.0) and height SDS decreased from +1.3 to +0.6 (target height: +0.2). Random non......-fasting serum GH values were mean 5.0 mlU/l (range: 1.6-9.5). There was no change in fasting blood glucose (4.6-4.7 mmol/l) or glycosylated haemoglobin (5.5%) and no subjective or biochemical side effects. Repeated tests of thyroid, adrenal and gonadal function showed no alterations during the treatment period...

  10. Specific differential phase observations of multicell convection during natural and triggered lightning strikes at the International Center for Lightning Research and Testing

    Science.gov (United States)

    Hyland, P.; Biggerstaff, M. I.; Uman, M. A.; Hill, J. D.; Krehbiel, P. R.; Rison, W.

    2012-12-01

    During the summers of 2011-2012, a C-band polarimetric Shared Mobile Atmospheric Research and Teaching (SMART) radar from the University of Oklahoma was deployed to Keystone Heights, FL to study the relationship between cloud structure and the propagation of triggered and natural lightning channels. The radar was operated in Range-Height-Indicator (RHI) volume scanning mode over a narrow azimuthal sector that provided high spatial vertical resolution every 90 seconds over the rocket launch facility at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL. In this presentation, we will focus on observations collected in 2011. Seven successful triggers (with return strokes) out of 20 attempts were sampled by the SMART-R from June to August. Most of the trigger attempts occurred during the dissipating stages of convection with steady ground electric field values. Specific differential phase (KDP) showed evidence of ice crystal alignment due to strong electric fields within the upper portions of the convection over ICLRT around the time of launch attempts. Consecutive RHI sweeps over ICLRT revealed changes in KDP that suggested the building of electric fields and subsequent relaxation after a triggered flash. KDP signatures relative to other radar variables will also be investigated to determine the microphysical and convective nature of the storms in which natural and triggered lightning strikes occurred. Lightning Mapping Array (LMA) sources of the triggered flash channels showed a preference for horizontal propagation just above the radar bright band associated with the melting layer. This finding agrees with several past studies that used balloon soundings and found intense layers of charge near the 0°C isotherm. The propagation path also seemed to be related to the vertical distribution of KDP in some of the triggered flashes. A preferred path through areas of generally positive values of KDP suggests that triggered lightning

  11. A Novel Concept for Observing Land-Surface-Atmosphere Feedback Based on a Synergy of Scanning Lidar Systems

    Science.gov (United States)

    Wulfmeyer, V.; Turner, D. D.; Mauder, M.; Behrendt, A.; Ingwersen, J.; Streck, T.

    2015-12-01

    Improved simulations of land-surface-atmosphere interaction are fundamental for improving weather forecast and climate models. This requires observations of 2D fields of surface fluxes and the 3D structure of the atmospheric boundary layer simultaneously. A novel strategy is introduced for studying land-surface exchange and entrainment processes in the convective boundary layer (CBL) over complex terrain by means of a new generation of remote sensing systems. The sensor synergy consists of scanning Doppler lidar (DL), water-vapor differential absorption lidar (WVDIAL), and temperature rotational Raman lidar (TRRL) systems supported by surface in-situ measurements. The 2D measurements of surface fluxes are realized by the operation of a DL, a WVDIAL, and a TRRL along the same line-of-sight (LOS) in a range-height-indicator (RHI) mode whereas the other DL is performing a series of cross track RHI scans along this LOS. This new setup enables us to determine the friction velocity as well as surface sensible and latent heat fluxes by closing the complete set of Monin-Obukhov similarity relationships under a variety of surface layer stability conditions and different land cover and soil properties. As this closure is performed at all DL crossing points along the LOS, this is a strategy towards a 2D mapping of surface fluxes entirely based on remote sensing systems. Further details are presented at the conference. The second configuration is the simultaneous vertical profiling of vertical wind, humidity and temperature by DL, WVDIAL and TRRL so that latent heat and sensible heat flux profiles as well as a variety of different turbulent moments can be measured in the CBL. Consequently, by alternating of RHI scanning and vertical pointing modes, entrainment fluxes and surface fluxes can be measured almost simultaneously. This novel strategy has been realized for the first time during the Surface Atmospheric Boundary Layer Exchange (SABLE) campaign in the Kraichgau region

  12. Land-Atmosphere Feedback Experiment (LAFE) Science Plan

    Energy Technology Data Exchange (ETDEWEB)

    Wulfmeyer, Volker [University of Hohenheim; Turner, David [NOAA National Severe Storms Laboratory

    2016-07-01

    The Land-Atmosphere Feedback Experiment (LAFE; pronounced “la-fey”) deploys several state-of-the-art scanning lidar and remote sensing systems to the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains (SGP) site. These instruments will augment the ARM instrument suite in order to collect a data set for studying feedback processes between the land surface and the atmosphere. The novel synergy of remote-sensing systems will be applied for simultaneous measurements of land-surface fluxes and horizontal and vertical transport processes in the atmospheric convective boundary layer (CBL). The impact of spatial inhomogeneities of the soil-vegetation continuum on land-surface-atmosphere (LSA) feedback will be studied using the scanning capability of the instrumentation. The time period of the observations is August 2017, because large differences in surface fluxes between different fields and bare soil can be observed, e.g., pastures versus fields where the wheat has already been harvested. The remote sensing system synergy will consist of three components: 1) The SGP water vapor and temperature Raman lidar (SRL), the SGP Doppler lidar (SDL), and the National Center for Atmospheric Research (NCAR) water vapor differential absorption lidar (DIAL) (NDIAL) mainly in vertical staring modes to measure mean profiles and gradients of moisture, temperature, and horizontal wind. They will also measure profiles of higher-order turbulent moments in the water vapor and wind fields and profiles of the latent heat flux. 2) A novel scanning lidar system synergy consisting of the National Oceanic and Atmospheric Administration (NOAA) High-Resolution Doppler lidar (HRDL), the University of Hohenheim (UHOH) water-vapor differential absorption lidar (UDIAL), and the UHOH temperature Raman lidar (URL). These systems will perform coordinated range-height indicator (RHI) scans from just above the canopy level to the

  13. Direct Detection 1.6?m DIAL / Doppler Lidar for Measurements of CO2 Concentration and Wind Profiles (Invited)

    Science.gov (United States)

    Shibata, Y.; Nagasawa, C.; Abo, M.

    2013-12-01

    Knowledge of present carbon sources and sinks including their spatial distribution and their variation in time is one of the essential information for predicting future CO2 atmospheric concentration levels. Moreover, wind information is an important parameter for transport simulations and inverse estimation of surface CO2 flux. The differential absorption lidar (DIAL) and the Doppler wind lidar with the range resolution is expected to measure atmospheric CO2 profiles and wind profiles in the atmospheric boundary layer and lower troposphere from a ground platform. We have succeeded to develop a scanning 1.6 μm DIAL and incoherent Doppler lidar system for simultaneously measuring CO2 concentration and wind speed profiles. Our 1.6 μm DIAL system consists of the Optical Parametric Generator (OPG) transmitter that excited by the LD pumped Nd: YAG laser with high repetition rate (500 Hz) and the receiving optics that included the near-infrared photomultiplier tube with high quantum efficiency operating at the photon counting mode, a fiber Bragg grating (FBG) filter to detect a Doppler shift, and a 25 cm telescope [1] [2]. We had developed an optical parametric oscillator (OPO) system for 1.6 μm CO2 DIAL[3]. To achieve continuous tuning of the resonant OPO output without mode hopping, it is necessary to vary the OPO cavity length synchronously with the seed-frequency. On the other hand, the OPG does not require a cavity and instead rely on sufficient conversion efficiency to be obtained with a single pass through the crystal. The single-frequency oscillation of the OPG was achieved by injection seeding. The CO2-DIAL was operated with the range-height indicator (RHI) mode, and the 2-D measurement provided inhomogeneity in the boundary layer. Vertical CO2 concentration profiles and wind profiles were also measured simultaneously. The elevation angle was fixed at 52 deg and CO2 concentration profiles were obtained up to 1 km altitude with 200 m height resolution. Vertical