Note: This page contains sample records for the topic cloud motion vector from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

MISR Level 3 Cloud Motion Vector  

MISR Level 3 Cloud Motion Vector Level 3 Wednesday, November 7, 2012 ... A new version, F02_0002, of the MISR L3 CMV (Cloud Motion Vector) data product is now available. This new release provides finer ... coverage. These enhancements are the result of reorganizing motion vector information present in the recent Level 2 Cloud product as ...

2013-07-10

2

Cloud Motion Vectors from MISR using Sub-pixel Enhancements  

NASA Technical Reports Server (NTRS)

The operational retrieval of height-resolved cloud motion vectors by the Multiangle Imaging SpectroRadiometer on the Terra satellite has been significantly improved by using sub-pixel approaches to co-registration and disparity assessment, and by imposing stronger quality control based on the agreement between independent forward and aft triplet retrievals. Analysis of the fore-aft differences indicates that CMVs pass the basic operational quality control 67% of the time, with rms differences - in speed of 2.4 m/s, in direction of 17 deg, and in height assignment of 290 m. The use of enhanced quality control thresholds reduces these rms values to 1.5 m/s, 17 deg and 165 m, respectively, at the cost of reduced coverage to 45%. Use of the enhanced thresholds also eliminates a tendency for the rms differences to increase with height. Comparison of CMVs from an earlier operational version that had slightly weaker quality control, with 6-hour forecast winds from the Global Modeling and Assimilation Office yielded very low bias values and an rms vector difference that ranged from 5 m/s for low clouds to 10 m/s for high clouds.

Davies, Roger; Horvath, Akos; Moroney, Catherine; Zhang, Banglin; Zhu, Yanqiu

2007-01-01

3

Comparison of MISR and Meteosat-9 cloud-motion vectors  

NASA Astrophysics Data System (ADS)

Stereo motion vectors (SMVs) from the Multiangle Imaging SpectroRadiometer (MISR) were evaluated against Meteosat-9 cloud-motion vectors (CMVs) over a one-year period. In general, SMVs had weaker westerlies and southerlies than CMVs at all latitudes and levels. The E-W wind comparison showed small vertical variations with a mean difference of -0.4 m s-1, -1 m s-1, -0.7 m s-1 and corresponding rmsd of 2.4 m s-1, 3.8 m s-1, 3.5 m s-1for low-, mid-, and high-level clouds, respectively. The N-S wind discrepancies were larger and steadily increased with altitude, having a mean difference of -0.8 m s-1, -2.9 m s-1, -4.4 m s-1 and rmsd of 3.5 m s-1, 6.9 m s-1, 9.5 m s-1at low, mid, and high levels. The best overall agreement was found in marine stratocumulus off Namibia, while differences were larger in the Tropics and convective clouds. The SMVs were typically assigned to higher altitudes than CMVs. Attributing each observed height difference to MISR and/or Meteosat-9 retrieval biases will require further research; nevertheless, we already identified a few regions and cloud types where CMV height assignment seemed to be the one in error. In thin mid- and high-level clouds over Africa and Arabia as well as in broken marine boundary layer clouds the 10.8-?m brightness temperature-based heights were often biased low due to radiance contributions from the warm surface. Contrarily, low-level CMVs in the South Atlantic were frequently assigned to mid levels by the CO2-slicing method in multilayer situations. We also noticed an apparent cross-swath dependence in SMVs, whereby retrievals were less accurate on the eastern side of the MISR swath than on the western side. This artifact was traced back to sub-pixel MISR co-registration errors, which introduced cross-swath biases in E-W wind, N-S wind, and height of 0.6 m s-1, 2.6 m s-1, and 210 m.

Lonitz, Katrin; HorváTh, ÁKos

2011-12-01

4

The MISR Cloud Motion Vector Product: 10 years of height resolved, cloud-track winds  

NASA Astrophysics Data System (ADS)

By utilizing multiple camera views and fast image matching algorithms to identify common features and determine feature motion, the MISR instrument on NASA’s Terra satellite has now collected 10 years of height-resolved, cloud-track, vector winds using a single, globally consistent algorithm. MISR cloud-track winds are packaged within the new MISR Cloud Motion Vector product, reported on mesoscale domains of 70.4 km × 70.4 km and referenced to stereoscopically derived heights above the earth ellipsoid with a nominal precision of 230 m. Importantly, from the standpoint of climate research, the stereo height assignment and wind retrieval are largely insensitive to instrument calibration changes and independent of a priori assumptions because the product algorithms depend only on patterns of observed brightness variability. We will describe comparisons with other wind observations, including geostationary cloud drift winds, raob winds, and scatterometer surface winds that demonstrate the quality of the MISR winds. We will also show the coverage and resolution advantages that MISR provides relative to these other datasets. Additionally, we will analyze agreement and discrepancies between MISR winds and reanalysis winds.

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

2010-12-01

5

MISR 17.6 KM Gridded Cloud Motion Vectors: Overview and Assessment  

NASA Technical Reports Server (NTRS)

The MISR (Multi-angle Imaging SpectroRadiometer) instrument on the Terra satellite has been retrieving cloud motion vectors (CMVs) globally and almost continuously since early in 2000. In February 2012 the new MISR Level 2 Cloud product was publicly released, providing cloud motion vectors at 17.6 km resolution with improved accuracy and roughly threefold increased coverage relative to the 70.4 km resolution vectors of the current MISR Level 2 Stereo product (which remains available). MISR retrieves both horizontal cloud motion and height from the apparent displacement due to parallax and movement of cloud features across three visible channel (670nm) camera views over a span of 200 seconds. The retrieval has comparable accuracy to operational atmospheric motion vectors from other current sensors, but holds the additional advantage of global coverage and finer precision height retrieval that is insensitive to radiometric calibration. The MISR mission is expected to continue operation for many more years, possibly until 2019, and Level 2 Cloud has the possibility of being produced with a sensing-to-availability lag of 5 hours. This report compares MISR CMV with collocated motion vectors from arctic rawinsonde sites, and from the GOES and MODISTerra instruments. CMV at heights below 3 km exhibit the smallest differences, as small as 3.3 m/s for MISR and GOES. Clouds above 3 km exhibit larger differences, as large as 8.9 m/s for MISR and MODIS. Typical differences are on the order of 6 m/s.

Mueller, Kevin; Garay, Michael; Moroney, Catherine; Jovanovic, Veljko

2012-01-01

6

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

7

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

8

Operational Cloud-Motion Winds from Meteosat Infrared Images  

Microsoft Academic Search

The displacement of clouds in successive satellite images reflects the atmospheric circulation at various scales. The main application of the satellite-derived cloud-motion vectors is their use as winds in the data analysis for numerical weather prediction. At low latitudes in particular they constitute an indispensible data source for numerical weather prediction.This paper describes the operational method of deriving cloud-motion winds

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

1993-01-01

9

Wind estimates from cloud motions: Phase 1 of an in situ aircraft verification experiment  

NASA Technical Reports Server (NTRS)

An initial experiment was conducted to verify geostationary satellite derived cloud motion wind estimates with in situ aircraft wind velocity measurements. Case histories of one-half hour to two hours were obtained for 3-10km diameter cumulus cloud systems on 6 days. Also, one cirrus cloud case was obtained. In most cases the clouds were discrete enough that both the cloud motion and the ambient wind could be measured with the same aircraft Inertial Navigation System (INS). Since the INS drift error is the same for both the cloud motion and wind measurements, the drift error subtracts out of the relative motion determinations. The magnitude of the vector difference between the cloud motion and the ambient wind at the cloud base averaged 1.2 m/sec. The wind vector at higher levels in the cloud layer differed by about 3 m/sec to 5 m/sec from the cloud motion vector.

Hasler, A. F.; Shenk, W. E.; Skillman, W.

1974-01-01

10

Impact of assimilation of INSAT cloud motion vector (CMV) wind for the prediction of a monsoon depression over Indian Ocean using a mesoscale model  

NASA Astrophysics Data System (ADS)

The present study utilized the Penn State/NCAR mesoscale model (MM5), to assimilate the INSAT-CMV (Indian National Satellite System-Cloud Motion Vector) wind observations using analysis nudging to improve the prediction of a monsoon depression which occurred over the Arabian Sea, India during 14 September 2005 to 17 September 2005. NCEP-FNL analysis has been utilized as the initial and lateral boundary conditions and two sets of numerical experiments were designed to reveal the impact of assimilation of satellite-derived winds. The model was integrated from 14 September 2005 00 UTC to 17 September 2005 00 UTC, with just the NCEP FNL analysis in the NOFDDA run. In the FDDA run, the NCEP FNL analysis fields were improved by assimilating the INSAT-CMV (wind speed and wind direction) as well as QuickSCAT sea surface winds during the 24 hour pre-forecast period (14 September 2005 00 UTC to 15 September 2005 00 UTC) using analysis nudging. The model was subsequently run in the free forecast mode from 15 September 2005 00 UTC to 17 September 2005 12 UTC. The simulated sea level pressure field from the NOFDDA run reveals a relatively stronger system as compared to the FDDA run. However, the sea level pressure fields corresponding to the FDDA run are closer to the analysis. The simulated lower tropospheric winds from both experiments reveal a well-developed cyclonic circulation as compared to the analysis.

Xavier, V. F.; Chandrasekar, A.; Singh, Devendra

2006-12-01

11

Application of Automatic Method to Estimating High-Level Cloud Motion Wind in Operational System and the Characteristics of the Resultant Wind Vectors.  

National Technical Information Service (NTIS)

In order to apply the automatic method for calculating the high-level cloud motion winds to the operational system at the Meteorological Satellite Center (MSC), the improvement of the algorithm for calculating the high-level wind was carried out, and the ...

T. Ohshima

1988-01-01

12

Study to determine cloud motion from meteorological satellite data  

NASA Technical Reports Server (NTRS)

Processing techniques were tested for deducing cloud motion vectors from overlapped portions of pairs of pictures made from meteorological satellites. This was accomplished by programming and testing techniques for estimating pattern motion by means of cross correlation analysis with emphasis placed upon identifying and reducing errors resulting from various factors. Techniques were then selected and incorporated into a cloud motion determination program which included a routine which would select and prepare sample array pairs from the preprocessed test data. The program was then subjected to limited testing with data samples selected from the Nimbus 4 THIR data provided by the 11.5 micron channel.

Clark, B. B.

1972-01-01

13

Using raw MPEG motion vectors to determine global camera motion  

Microsoft Academic Search

This paper presents a simple and effective method to determine global camera motion using raw MPEG-1 motion vectors information obtained straight form real MPEG-1 streams such as those of the new HITACHI MP-EG1A digital camcorder. The simple approach we have experimented with robustly fits a global affine optic flow model to the motion vectors. Other more robust methods are also

Maurizio Pilu

1998-01-01

14

A Fourier approach to cloud motion estimation  

NASA Technical Reports Server (NTRS)

A Fourier technique is described for estimating cloud motion from pairs of pictures using the phase of the cross spectral density. The method allows motion estimates to be made for individual spatial frequencies, which are related to cloud pattern dimensions. Results obtained are presented and compared with the results of a Fourier domain cross correlation scheme. Using both artificial and real cloud data show that the technique is relatively sensitive to the presence of mixtures of motions, changes in cloud shape, and edge effects.

Arking, A.; Lo, R. C.; Rosenfield, A.

1977-01-01

15

Using raw MPEG motion vectors to determine global camera motion  

NASA Astrophysics Data System (ADS)

This paper presents a simple and effective method to determine global camera motion using raw MPEG-1 motion vectors information obtained straight form real MPEG-1 streams such as those of the new HITACHI MP-EG1A digital camcorder. The simple approach we have experimented with robustly fits a global affine optic flow model to the motion vectors. Other more robust methods are also proposed. In order to cope with the group-of-frames (GOF) discontinuity of the MPEG stream, B frames are used backward to determine the 'missing link' to a previous GOF thereby ensuring continuity of the motion estimation across a reasonable number of frames. As a tested, we have applied the method to the image mosaicing problem, for which interesting results have been obtained. Although several other methods exists to perform camera motion estimation, the approach presented here is particularly interesting because exploits 'free' information present in MPEG streams and bypass the highly expensive correlation process.

Pilu, Maurizio

1998-01-01

16

Generation method of normal vector from disordered point cloud  

Microsoft Academic Search

The normal vector generation from point cloud plays a vital role in 3D laser scanning data processing. An effective generation method of normal vector from disordered point cloud is proposed in the paper. In the proposed method, disordered point cloud is firstly projected on the 2D plane via cylindrical surface. After establishing the triangle grids, the unit normal vector of

Zheng De-hua; Xu Jia; Chen Ren-xi

2009-01-01

17

Atmospheric Motions from Sodium Cloud Drifts  

Microsoft Academic Search

Horizontal motions from 25 sodium cloud experiments are examined in the alti- tude range from 70 to 190 km. The outstanding characteristics of the apparent motion are pro- nounced velocity oscillations in the 70- to 130-km layer; they reach a maximum near 105 km and attenuate at greater heights. A quiescent zone appears from 140 to 190 km, where, despite

Adam Kochanski

1964-01-01

18

New fast algorithms for the estimation of block motion vectors  

Microsoft Academic Search

Two algorithms for block motion estimation that produce performance similar to that of exhaustive search but with computation reduced by a factor of 8 or 16 are presented. The algorithms are based on motion-field and pixel subsampling. A subsampled motion field is first determined by estimating the motion vectors for a fraction of the blocks. The motion vectors for these

Bede Liu; Andre Zaccarin

1993-01-01

19

Motion Vector Refinement for High-Performance Transcoding  

Microsoft Academic Search

In transcoding, simply reusing the motion vectors extracted from an incoming video bit stream may not result in the best quality. In this paper, we show that the incoming motion vectors become nonoptimal due to the reconstruction errors. To achieve the best video quality possible, a new motion estimation should be performed in the transcoder. We propose a fast-search adaptive

Jeongnam Youn; Ming-ting Sun; Chia-wen Lin

1999-01-01

20

Thunderstorm-associated cloud motions as computed from 5-minute SMS pictures. [Synchronous Meteorological Satellite  

NASA Technical Reports Server (NTRS)

The five-minute rapid-scan imagery from the Synchronous Meteorological Satellite is employed to study cloud motions associated with the Omaha tornado of May 6, 1975. Cloud-motion vectors derived from automated and man-machine interactive systems provide an account of the mesoscale phenomena. In addition to the geostationary satellite data, aerial photography obtained during a cloud-truth mission is used in the severe storm investigation. For tracking overland cumuli with short half-lives, a three-minute scan interval appears necessary for the satellite imagery.

Tecson, J. J.; Umenhofer, T. A.; Fujita, T. T.

1977-01-01

21

Motion/imagery secure cloud enterprise architecture analysis  

NASA Astrophysics Data System (ADS)

Cloud computing with storage virtualization and new service-oriented architectures brings a new perspective to the aspect of a distributed motion imagery and persistent surveillance enterprise. Our existing research is focused mainly on content management, distributed analytics, WAN distributed cloud networking performance issues of cloud based technologies. The potential of leveraging cloud based technologies for hosting motion imagery, imagery and analytics workflows for DOD and security applications is relatively unexplored. This paper will examine technologies for managing, storing, processing and disseminating motion imagery and imagery within a distributed network environment. Finally, we propose areas for future research in the area of distributed cloud content management enterprises.

DeLay, John L.

2012-05-01

22

Wind estimates from cloud motions: Preliminary results from phases 1, 2, and 3 of an in situ aircraft verification experiment  

NASA Technical Reports Server (NTRS)

Low level aircraft equipped with Inertial Navigation Systems (INS) were used to define the vertical extent and horizontal motion of a cloud and to measure the ambient wind field. A high level aircraft, also equipped with an INS, took photographs to describe the horizontal extent of the cloud field and to measure cloud motion. The aerial photographs were also used to make a positive identification in a satellite picture of the cloud observed by the low level aircraft. The experiment was conducted over the tropical oceans in the vicinity of Florida, Puerto Rico, Panama and in the Western Gulf of Mexico. Results for tropical cumulus clouds indicate excellent agreement between the cloud motion and the wind at the cloud base. The magnitude of the vector difference between the cloud motion and the cloud base wind is less than 1.3 m/sec for 67% of the cases with track lengths of 1 hour or longer. The cirrus cloud motions agreed best with the mean wind in the cloud layer with a vector difference of about 1.6 m/sec.

Hasler, A. F.; Shenk, W. E.; Skillman, W. C.

1975-01-01

23

Building Mosaics from Video using MPEG Motion Vectors.  

National Technical Information Service (NTIS)

In this paper, we present a novel way of creating mosaics from an MPEG video sequence. Two original aspects of our work are that (1) we explicitly compute camera motion between frames and (2) we deduce the camera motion directly from the motion vectors en...

D. DeMenthon D. S. Doermann R. C. Jones

1999-01-01

24

Recovery of lost or erroneously received motion vectors  

Microsoft Academic Search

A technique using boundary matching to compensate for lost or erroneously received motion vectors in motion-compensated video coding is proposed. This technique, called the boundary matching algorithm, produces noticeably better results than those reported previously. It is first assumed that the displaced frame differences have no error. Then, this assumption is relaxed by proposing an algorithm (the extended boundary matching

W. M. Lam; A. R. Reibman; B. Liu

1993-01-01

25

Proper motion study of the Magellanic Clouds using SPM material  

NASA Astrophysics Data System (ADS)

Absolute proper motions are determined for stars and galaxies to V = 17.5 over a 450 square-degree area that encloses both Magellanic Clouds. The proper motions are based on photographic and CCD observations of the Yale/San Juan Southern Proper Motion program. Multiple, local relative proper motion measures are combined in an overlap solution using photometrically selected Galactic disk stars to define a global relative system that is then transformed to absolute using external galaxies and Hipparcos stars to tie into the ICRS. The resulting catalog of 1.4 million objects is used to derive the mean absolute proper motions of the Large Magellanic Cloud and the Small Magellanic Cloud; (?_{?} cos ?, ?_{?})_{LMC} = (+1.89,+0.39)±(0.27,0.27) mas yr^{-1} and (?_{?} cos ?, ?_{?})_{SMC} = (+ 0.98,-1.10)±(0.30,0.29) mas yr^{-1}. These mean motions are based on best-measured samples of 3822 LMC stars and 964 SMC stars. A more precise determination can be made for the proper motion of the SMC relative to the LMC; (?_{?} cos ?, ?_{?})_{SMC-LMC} = (-0.91, -1.49)±(0.16,0.15) mas yr^{-1}. This differential value is combined with measurements of the proper motion of the LMC taken from the literature to produce new absolute proper motion determinations for the SMC, as well as an estimate of the total velocity difference of the two clouds to within 54 km s^{-1}.

Vieira, K.; Girard, T.; van Altena, W.; Zacharias, N.; Casetti-Dinescu, D.; Korchagin, V.; Platais, I.; Monet, D.; López, C.

2011-10-01

26

Clouds on Neptune: Motions, Evolution, and Structure  

NASA Technical Reports Server (NTRS)

The aims of our original proposal were these: (1) improving measurements of Neptune's circulation, (2) understanding the spatial distribution of cloud features, (3) discovery of new cloud features and understanding their evolutionary process, (4) understanding the vertical structure of zonal cloud patterns, (5) defining the structure of discrete cloud features, and (6) defining the near IR albedo and light curve of Triton. Towards these aims we proposed analysis of existing 1996 groundbased NSFCAM/IRTF observations and nearly simultaneous WFPC2 observations from the Hubble Space Telescope. We also proposed to acquire new observations from both HST and the IRTF.

Sromovsky, Larry A.; Morgan, Thomas (Technical Monitor)

2001-01-01

27

Rapid ray motions in barium plasma clouds and auroras  

NASA Technical Reports Server (NTRS)

On two evenings in 1968, anomalous field-aligned brightenings or emission enhancements of up to 3X were observed to move rapidly through three different Ba(+) clouds over Andoya, Norway. Similar effects were observed in Ba(+) clouds released from rockets launched from Poker Flat, Alaska, on March 21, 1973 and on March 22, 1980. On these occasions, auroras on or near the Ba(+) L shell also exhibited active rapid ray motions, which prompts the assumption that the two phenomena are related and the expectation that an explanation of the rapid ray motions in the Ba(+) clouds would lead to a better understanding of the physics of auroral ray motions and the auroral atmosphere. Seven possible mechanisms to produce the observed moving emission enhancements are discussed. The observations provide strong evidence for the existence of transient electric fields of order 100 mV/m at altitudes as low as 200 km during active aurora with rapid ray motions.

Wescott, E. M.; Hallinan, T. J.; Stenbaek-Nielsen, H. C.; Swift, D. W.; Wallis, D. D.

1993-01-01

28

Proper motion study of the Magellanic Clouds using SPM data  

NASA Astrophysics Data System (ADS)

This investigation has made use of plate and CCD material of the Yale-San Juan Southern Proper Motion program, to obtain a catalog of absolute proper motions in an area of 450 square-degree that encloses the Magellanic Clouds and includes 1,448,438 objects. The main goal has been to obtain an independent measurement of the mean proper motion of the Large and Small Magellanic Clouds, in view of the most recent space-based proper motions which challenge the standard picture of the Clouds as a binary system of galaxies that travel in a bound orbit around the Galaxy. Locally measured relative proper motions were assembled together on a very precise extended relative reference frame, defined by the mean motion of photometrically selected Galactic Disk stars. External galaxies and the Hipparcos Catalogue were used to transform the proper motions into the ICRS. Two samples of 3822 LMC stars and 964 SMC stars were selected from the catalog to measure the mean proper motion of the Magellanic Clouds. The results obtained are: (mualpha cos delta, mudelta) LMC +/- (1.89, +0.39) + (0.27, 0.27) mas yr-1and (mualpha cos delta, mudelta) SMC = (0.98, - 1.01)+/-(0.30, 0.29) mas yr -1. We have also obtained a much more precise proper motion of the SMC with respect to the LMC: (mualpha cos delta, mu delta)SMC--LMC = (-0.91, -1.49) +/- (0.16, 0.15) mas yr-1, which was used to obtain new independent and more precise proper motions for the SMC, based on more accurate LMC proper motions of other authors, and also to measure the relative velocity of SMC with respect to LMC within 54 km s-1, similar in precision to other ground- and space-based works. After comparison with previous results and the analysis of the orbit of the Clouds obtained from our proper motions, we conclude that our numbers are consistent with the Clouds being born and formed as separate entities, which later joined in a temporary binary state for the past few Gigayears, being recently disrupted by the Milky Way in their most recent perigalaticon passage about 200 Myr ago. The Clouds orbits are marginally bound to the Milky Way, possibly following a very ellongated but still periodic orbit around the Galaxy.

Vieira Villarreal, Rosa Katherine

29

The role of the harmonic vector average in motion integration  

PubMed Central

The local speeds of object contours vary systematically with the cosine of the angle between the normal component of the local velocity and the global object motion direction. An array of Gabor elements whose speed changes with local spatial orientation in accordance with this pattern can appear to move as a single surface. The apparent direction of motion of plaids and Gabor arrays has variously been proposed to result from feature tracking, vector addition and vector averaging in addition to the geometrically correct global velocity as indicated by the intersection of constraints (IOC) solution. Here a new combination rule, the harmonic vector average (HVA), is introduced, as well as a new algorithm for computing the IOC solution. The vector sum can be discounted as an integration strategy as it increases with the number of elements. The vector average over local vectors that vary in direction always provides an underestimate of the true global speed. The HVA, however, provides the correct global speed and direction for an unbiased sample of local velocities with respect to the global motion direction, as is the case for a simple closed contour. The HVA over biased samples provides an aggregate velocity estimate that can still be combined through an IOC computation to give an accurate estimate of the global velocity, which is not true of the vector average. Psychophysical results for type II Gabor arrays show perceived direction and speed falls close to the IOC direction for Gabor arrays having a wide range of orientations but the IOC prediction fails as the mean orientation shifts away from the global motion direction and the orientation range narrows. In this case perceived velocity generally defaults to the HVA.

Johnston, Alan; Scarfe, Peter

2013-01-01

30

Fast motion vector estimation by using spatiotemporal correlation of motion field  

Microsoft Academic Search

Motion vector (MV) estimation plays an important role in motion compensated video coding. In this research, we first examine a stochastic MV model which enables us to exploit the strong correlation of MVs in both spatial and temporal domains in a given image sequence. Then, a new fast stochastic block matching algorithm (SBMA) is proposed. The basic idea is to

Sungook Kim; Junavit Chalidabhongse; C.-C. J. Kuo

1995-01-01

31

OGLE3 Magellanic Clouds High proper motion stars (Poleski+, 2011)  

NASA Astrophysics Data System (ADS)

We present the results of a search for High Proper Motion (HPM) stars, i.e., the ones with pm>100mas/yr, in the direction to the Magellanic Clouds. This sky area was not examined in detail as the high stellar density hampers efforts in performing high-quality astrometry. (4 data files).

Poleski, R.; Soszynski, I.; Udalski, A.; Szymanski, M. K.; Kubiak, M.; Pietrzynski, G.; Wyrzykowski, L.; Ulaczyk, K.

2011-10-01

32

The Proper Motion of the Large Magellanic Cloud Using HST  

Microsoft Academic Search

We present a measurement of the systemic proper motion of the Large Magellanic Cloud (LMC) from astrometry with the High Resolution Camera (HRC) of the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). We observed LMC fields centered on 21 background QSOs that were discovered from their optical variability in the MACHO database. The QSOs are distributed

Nitya Kallivayalil; Roeland P. van der Marel; Charles Alcock; Tim Axelrod; Kem H. Cook; A. J. Drake; M. Geha

2006-01-01

33

A study on the motion vector prediction schemes for AVS  

NASA Astrophysics Data System (ADS)

The motion vector prediction (MVP) is an important part of video coding. There have been numerous workings on the topic done by researchers before. In this paper, a continue study on MVP of video coding based on the workings of predecessors is made. The video sequences with various motion characteristics are further investigated. The characteristics of motion vectors of objects in video scenes are discussed briefly. Then, summarizing these characteristics, two MVP schemes for a new coding standard, Audio and Video Standard (AVS), are proposed. In these schemes, current block"s MV can be predicted based on statistical correlation of MVs of spatial contiguous neighbor blocks. A correlation criterion is employed to measure how correlated between two MVs. With the correlation criterion, the correlated MVs of neighbor blocks are determined. Then, the predicted MV of current block can be obtained with some simple algebraic operations on determined MVs. The two proposed schemes, as the alternative ones of median predictor, are suitable for different video sequences with different motion characteristics, respectively. The experimental results show that the bit rate savings are achieved with these schemes in most of typical video sequences, compared with the median predictor implemented in AVS.

Qi, Honggang; Gao, Wen; Ma, Siwei; Zhao, Debin

2005-07-01

34

Digital video steganalysis using motion vector recovery-based features.  

PubMed

As a novel digital video steganography, the motion vector (MV)-based steganographic algorithm leverages the MVs as the information carriers to hide the secret messages. The existing steganalyzers based on the statistical characteristics of the spatial/frequency coefficients of the video frames cannot attack the MV-based steganography. In order to detect the presence of information hidden in the MVs of video streams, we design a novel MV recovery algorithm and propose the calibration distance histogram-based statistical features for steganalysis. The support vector machine (SVM) is trained with the proposed features and used as the steganalyzer. Experimental results demonstrate that the proposed steganalyzer can effectively detect the presence of hidden messages and outperform others by the significant improvements in detection accuracy even with low embedding rates. PMID:22781241

Deng, Yu; Wu, Yunjie; Zhou, Linna

2012-07-10

35

The effect of wind and moisture gradients on the arbitrary assignment of cloud motions to a vertical coordinate system in two Sesame cases  

NASA Technical Reports Server (NTRS)

Satellite-derived cloud motion 'wind' vectors (CMV) are increasingly used in mesoscale and in global analyses, and questions have been raised regarding the uncertainty of the level assignment for the CMV. One of two major problems in selecting a level for the CMV is related to uncertainties in assigning the motion vector to either the cloud top or base. The second problem is related to the inability to transfer the 'wind' derived from the CMV at individually specified heights to a standard coordinated surface. The present investigation has the objective to determine if the arbitrary level assignment represents a serious obstacle to the use of cloud motion wind vectors in the mesoscale analysis of a severe storm environment.

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

1984-01-01

36

New MISR Cloud Data  

... are provided for 70% of clouds observed by MISR with vector RMS difference from atmospheric motion vectors from other sources ranging from ... m/s. Cloud top heights are provided for 80% of clouds with RMS differences of less than 1 km (the same as for the existing Level 2 Stereo ...

2013-08-06

37

Object Tracking Algorithm Based on Meanshift Algorithm Combining with Motion Vector Analysis  

Microsoft Academic Search

Mean shift algorithm doesn't use the targetpsilas motion direction and speed information in process of object tracking. When the targetpsilas speed is so fast it easily fails to track the target. So a new object tracking algorithm combining Mean shift algorithm with Motion Vector analysis is proposed in this paper. By statistical analysis of the motion vector get from video

Tian Gang; Hu Rui-Min; Wang Zhong-Yuan; Zhu Li

2009-01-01

38

Temporal prediction of block motion vectors with local ambiguity-based adaptivity  

Microsoft Academic Search

The computational burden of full search block matching algorithms for motion estimation in video coding can be reduced through exploitation of spatial and temporal correlation of the motion vectors. This paper describes a simple adaptive temporal prediction scheme for block motion vectors. The first-order temporal predictor determines the center of the search area for a conventional block match, but with

Stephen O'Halek; Ken D. Sauer

1994-01-01

39

Fast motion vector estimation by using spatiotemporal correlation of motion field  

NASA Astrophysics Data System (ADS)

Motion vector (MV) estimation plays an important role in motion compensated video coding. In this research, we first examine a stochastic MV model which enables us to exploit the strong correlation of MVs in both spatial and temporal domains in a given image sequence. Then, a new fast stochastic block matching algorithm (SBMA) is proposed. The basic idea is to select a set of good MV candidates and choose from them the one which satisfies a certain spatio-temporal correlation rule. The proposed algorithm reduces matching operations to about 2% of that of the full block matching algorithm (FBMA) with only 2% increase of the sum of absolute difference (SAD) in motion compensated residuals. The excellent performance of the new algorithm is supported by extensive experimental results.

Kim, Sungook; Chalidabhongse, Junavit; Kuo, C.-C. Jay

1995-04-01

40

Influence of shear motion on evolution of molecular clouds in the spiral galaxy M 51  

NASA Astrophysics Data System (ADS)

We have investigated the dynamics of the molecular gas and the evolution of giant molecular associations (GMAs) in the spiral galaxy M 51 with the Nobeyama Radio Observatory 45-m telescope. The velocity components of the molecular gas perpendicular and parallel to the spiral arms are derived at each spiral phase from the distribution of the line-of-sight velocity of the CO gas. In addition, the shear motion in the galactic disk is determined from the velocity vectors at each spiral phase. It is revealed that the distributions of the shear strength and of GMAs are anti-correlated. GMAs exist only in the area of the weak shear strength and further on the upstream side of the high shear strength. GMAs and most giant molecular clouds (GMCs) exist in the regions where the shear critical surface density is smaller than the gravitational critical surface density, indicating that they can stably grow by self-gravity and the collisional agglomeration of small clouds without being destroyed by shear motion. These factors indicate that the shear motion is an important factor in evolution of GMCs and GMAs.

Miyamoto, Yusuke; Nakai, Naomasa; Kuno, Nario

2014-04-01

41

On the normal vector estimation for point cloud data from smooth surfaces  

Microsoft Academic Search

Reliable estimation of the normal vector at a discrete data point in a scanned cloud data set is essential to the correct implementation of modern CAD\\/CAM technologies when the continuous CAD model representation is not available. A new method based on fitted directional tangent vectors at the data point has been developed to determine its normal vector. A local Voronoi

Daoshan Ouyang; Hsi-yung Feng

2005-01-01

42

The cost of data dependence in motion vector estimation for reconfigurable platforms  

Microsoft Academic Search

Motion vector estimation is frequently performed as a prelude to the exploitation of temporal redundancies in video applications. As a result, a large volume of work has been done to develop techniques to avoid the heavy memory access requirements of full search motion vector estimation. Often, these approaches introduce data dependence to the algorithm, leading to memory accesses which cannot

Su-Shin Ang; George Constantinides; Wayne Luk; Peter Cheung

2006-01-01

43

Improvement of image deblurring for opto-electronic joint transform correlator under projective motion vector estimation  

NASA Astrophysics Data System (ADS)

In this paper we propose an efficient algorithm to improve the performance of image deblurring based on opto-electronic joint transform correlator (JTC) that is capable of detecting the motion vector of a space camera. Firstly, the motion vector obtained from JTC is divided into many sub-motion vectors according to the projective motion path, which represents the degraded image as an integration of the clear scene under a sequence of planar projective transforms. Secondly, these sub-motion vectors are incorporated into the projective motion Richardson–Lucy (RL) algorithm to improve deblurred results. The simulation results demonstrate the effectiveness of the algorithm and the influence of noise on the algorithm performance is also statically analyzed.

Xiao, Xiao; Zhao, Hui; Zhang, Yang

2014-06-01

44

Atmospheric Motion Vectors Derived via a New Nested Tracking Algorithm Developed for the GOES-R Advanced Baseline Imager (ABI)  

NASA Astrophysics Data System (ADS)

A new Atmospheric Motion Vector (AMV) nested tracking algorithm has been developed for the Advanced Baseline Imager (ABI) to be flown on NOAA's future GOES-R satellite. The algorithm has been designed to capture the dominant motion in each target scene from a family of local motion vectors derived for each target scene. Capturing this dominant motion is achieved through use of a two-dimensional clustering algorithm that segregates local displacements into clusters. The dominant motion is taken to be the average of the local displacements of points belonging to the largest cluster. This approach prevents excessive averaging of motion that may be occurring at multiple levels or at different scales that can lead to a slow speed bias and a poor quality AMV. A representative height is assigned to the dominant motion vector through exclusive use of cloud heights from pixels belonging to the largest cluster. This algorithm has been demonstrated to significantly improve the slow speed bias typically observed in AMVs derived from satellite imagery. Meteosat SEVERI imagery is serving as an important GOES-R ABI proxy data source for the development, testing, and validation of the GOES-R AMV algorithms given its similarities (spectral coverage, pixel resolution, and scanning rate) and performance (spectral noise, navigation/registration) to the future GOES-R ABI. The new GOES-R AMV algorithm is also being applied to the instrumentation on the current operational GOES series of satellites and is expected to replace the heritage AMV algorithm being used in NESDIS operations today. Plans at NOAA/NESDIS also include using the new GOES-R AMV algorithm to generate AMVs from the future VIIRS instrument on the NPP satellite. Details of the GOES-R ABI AMV algorithm and the validation results will be presented and discussed.

Daniels, J.; Bresky, W.; Wanzong, S.; Velden, C.

2012-12-01

45

Comparison of Kalpana-1 atmospheric motion vectors with other observations  

NASA Astrophysics Data System (ADS)

The operational derivation of atmospheric motion vectors (AMVs) using infrared (10.5-12.5 ?m) and water vapor (6.3-7.1 ?m) channels of successive geostationary satellite images started in the 1980s. Subsequently, AMVs have become an important component for operational numerical weather prediction throughout the globe for the last decade or so. In India, at the Space Applications Centre, Indian Space Research Organisation, the operational derivation of AMVs (infrared winds and water vapor winds) from the Indian geostationary satellite Kalpana-1 has been initiated a few years back. Recently, an L-band radar lower atmosphere wind profiler (LAWP) has been installed at the National Atmospheric Research Laboratory, Gadanki located at (13.58°N, 79.28°E) for continuous high-resolution wind measurements in the lower atmosphere. In this study, a comparison of Kalpana-1 AMVs with wind measurements from LAWP and radiosonde has been carried out for a period of one and a half years. The performances of Kalpana-1 AMVs are also assessed by a separate comparison of Meteosat-7 AMVs, derived at the European Organisation for the Exploitation of Meteorological Satellites, with wind measurements from LAWP and radiosonde. Both sets of comparison show that AMVs from Kalpana-1 and Meteosat-7 are comparable over the Indian Ocean region.

Deb, S. K.; Kaur, Inderpreet; Kishtawal, C. M.; Pal, P. K.

2014-02-01

46

Registration of motion-distorted interlaced images captured by a scanning vector imaging sensor  

Microsoft Academic Search

We present an algorithm to realign images distorted by motion and vibrations captured in cameras that use a scanning vector sensor with an interlaced scheme. In particular, the method is developed for images captured by a staggered time delay and integration camera distorted by motion. The algorithm improves the motion-distorted image by adjusting its fields irrespective of the type of

A. Avrin; A. Stern; N. S. Kopeika

2006-01-01

47

An adaptive mode-driven spatiotemporal motion vector prediction for wavelet video coding  

NASA Astrophysics Data System (ADS)

The three-dimensional subband/wavelet codecs use 5/3 filters rather than Haar filters for the motion compensation temporal filtering (MCTF) to improve the coding gain. In order to curb the increased motion vector rate, an adaptive motion mode driven spatiotemporal motion vector prediction (AMDST-MVP) scheme is proposed. First, by making use of the direction histograms of four motion vector fields resulting from the initial spatial motion vector prediction (SMVP), the motion mode of the current GOP is determined according to whether the fast or complex motion exists in the current GOP. Then the GOP-level MVP scheme is thereby determined by either the S-MVP or the AMDST-MVP, namely, AMDST-MVP is the combination of S-MVP and temporal-MVP (T-MVP). If the latter is adopted, the motion vector difference (MVD) between the neighboring MV fields and the S-MVP resulting MV of the current block is employed to decide whether or not the MV of co-located block in the previous frame is used for prediction the current block. Experimental results show that AMDST-MVP not only can improve the coding efficiency but also reduce the number of computation complexity.

Zhao, Fan; Liu, Guizhong; Qi, Yong

2010-07-01

48

A Method of Measuring the Axial Secular Motion Temperature of Trapping Large Size Ion Clouds  

NASA Astrophysics Data System (ADS)

A large cloud of 40Ca+ is successfully trapped and manipulated in a linear ion trap. The axial length of the ion cloud is measured under a series of end-cap voltages. We propose a method of measuring the axial secular motion temperature of the ion cloud by analyzing its image on an electron-multiplying CCD. The method is based on the Boltzmann equation that the axial density distribution of ions at secular motion temperature T satisfies. The axial secular motion temperature of the ion cloud is also obtained by measuring the Doppler broadened line width. For the same trapping parameters, the axial secular motion temperature by analyzing the image of ion cloud is 840 K and by fitting the experimental resonance line profile is 700 K.

Yang, Yu-Na; Liu, Hao; He, Yue-Hong; Li, Hai-Xia; Chen, Yi-He; She, Lei; Chen, Liang; Li, Jiao-Mei

2013-03-01

49

Quality Assessment of Atmospheric Motion Vectors Over the Indian Ocean  

NASA Astrophysics Data System (ADS)

Because conventional observations over the oceans are not available, especially during tropical cyclones, multi-spectral atmospheric motion vectors (AMVs) estimated from geostationary satellites are routinely assimilated in the numerical weather prediction models at different operational centres across the globe. The derived AMVs are generally validated with radiosonde observations available over land at synoptic hours; however, over the ocean there is a limited scope to assess the quality of AMVs. Over ocean, AMVs can be validated with radiosonde data available from opportunistic ships or using dropsonde data available from aircrafts. In this study, the accuracy of the AMVs derived from the geostationary satellites Kalpana-1 and Meteosat-7 is evaluated over the oceanic region. Radiosonde data available from a ship cruise held in the Bay of Bengal during the period 09 July-08 August 2012 and from the Cal/Val site situated at Kavaratti Island (72.62°E, 10.57°N) in the southern Indian Ocean are used to assess the AMV accuracy. In this study, 83 radiosonde profiles are used to validate the Kalpana-1 AMVs, to allow a better understanding of AMV errors over the Indian Ocean. The RMSVD of Kalpana-1 AMVs for the high-, mid- and low-levels are found to be 7.9, 9.4 and 5.3 m s-1, respectively, while the corresponding RMSVD for Meteosat-7 AMVs are 9.1, 5.5 and 3.7 m s-1. A similar accuracy is observed when the AMVs are validated against the NCEP analyses collocated with the nearest radiosonde locations. The high RMSVD and bias for Kalpana-1 AMVs at the mid-level and Meteosat-7 AMVs at the high-level are associated with the limitation of satellite winds to resolve the upper-level easterly jet in conjunction with errors in the height assignment. This study could help the numerical modellers to assign appropriate observation error over this region during the assimilation of AMVs into the NWP models.

Kaur, Inderpreet; Deb, S. K.; Kishtawal, C. M.; Pal, P. K.

2014-02-01

50

Clouds  

NSDL National Science Digital Library

First, the Project Atmosphere Canada offers a module to educate primary and secondary students about cloud formation and characteristics (1). The website outlines key points and offers a more in-depth discussion of water vapor, cloud formation, convection, air motion, severe weather, and more. The second website, by Scholastic, supplies many pdf documents of activities and lesson plans for all types of weather phenomena including clouds (2). Students can learn about condensation, discover what makes up a cloud, and find a key identifying the cloud types. Next, USA Today offers an online tutorial of the differing characteristics of clouds (3). Users can learn about Mammatus clouds, contrails, cloud seeding, and other cloud-related topics. At the fourth website, visitors can view meteorologist Dan Satterfield's amazing cloud photographs (4). Educators may find useful materials to supplement their lectures. Next, NASA's Climate and Radiation Branch furnishes "information on the fantastic variety of cloud forms and structures, and their implications for climate" (5). While the website is still being constructed, users can find useful information about the Bounded Cascades Fractal Cloud model, animations, and definitions of inhomogeneous cloud terminology. The sixth website, created by the National Center for Atmospheric Research and the University Corporation for Atmospheric Research, addresses how clouds impact our lives, how they cause chaos, and how they form (6). The enlightening descriptions are packed with colorful images and short quizzes. Next, The Australian Government's Bureau of Meteorology describes the useful of clouds as an indicator of weather conditions (7). After learning how moist air can form clouds, individuals can view images of the ten most common cloud types. Lastly, Enchanted Learning offers a table of the cloud types with their abbreviation, appearance, composition, and altitude along with explanations of cloud formation and the atmosphere (8). Educators can find simple activities dealing with cloud types and the water cycle.

51

Effect of GOES-R Image Navigation and Registration Errors on Atmospheric Motion Vectors  

NASA Technical Reports Server (NTRS)

High temporal frequency imagery from geostationary satellites allows for the continuous monitoring of rapidly changing atmospheric constituents such as smoke, dust, water vapor and clouds. The image sequences are often used to quantify the displacement of image features such as water vapor and clouds to produce atmospheric motion vectors (AMVs) which are used as diagnostic tools and also assimilated into numerical weather forecast models. The basic principle behind the determination of AMVs is the calculation of the physical displacement of features from one image (time) to the next. This process assumes that the features being tracked do not change as a function of time, usually requiring the use of short time interval imagery to minimize substantial change in size and shape of the features being tracked. High spatial resolution imagery also is required for reliable feature identification. While these image resolution and temporal sampling requirements often provide major drivers for space-based instrument design requirements, accurate image navigation and registration, INn (between a sequence of images), is also critical to the derivation of useful AMVs. In this paper and poster to be presented at the conference, the image navigation and registration (INR) accuracy expected for the Advanced Baseline Imager (ABI) on the GOES-R series of satellites will be discussed in light of its impact on AMV accuracy. Significant satellite platform and modeling enhancements are planned which should significantly improve INn performance of the GOES-R instruments. Some of these improvements have been demonstrated for the GOES-13 satellite which was launched in summer of 2006. An analysis of GOES-13 INR data, from the special satellite check out period, will be used in the assessment.

Jedlovec, Gary

2008-01-01

52

Novel block matching algorithm using predictive motion vector for video object tracking based on color histogram  

Microsoft Academic Search

Block matching motion estimation plays significant role for video processing and Computer Vision. Various methods based on mean shift and particle trackers are used to track the object on video sequence. Block matching algorithm is normally used for video compression technique. A novel, simple and fast block matching algorithm has been proposed using predictive motion vector for object tracking. Color

N. G. Chitaliya; A. I. Trivedi

2011-01-01

53

Observation of Hysteresis of the Ion Cloud Motion in an rf Trap  

NASA Astrophysics Data System (ADS)

Variations of the hysteresis of the rf detection signals corresponding to the axial motion of an ion cloud in a Paul trap versus the detection voltage, operation parameters and number of ions have been observed. The features are explained by an extended pseudopotential model with an octupole potential correction and an effective potential from the ion cloud.

Gao, Ke-lin; Luo, Xue-li; Zhu, Xi-wen; Yan, Min; Li, Jiao-mei

1997-08-01

54

Feasibility and Error Analysis of Cloud Motion Wind Extraction from Near-Simultaneous Multiangle MISR Measurements  

Microsoft Academic Search

Satellite wind measurements represent an invaluable contribution to the description of the flow field over the oceans. Conventional cloud-tracking techniques suffer from the inability to simultaneously determine wind speed and height. Currently, the uncertainty in the independently calculated heights is the major factor limiting the accuracy of cloud motion winds. Near-simultaneous multiangle imagery from the multiangle imaging spectro- radiometer (MISR)

Ákos Horváth; Roger Davies

2001-01-01

55

Insitu aircraft verification of the quality of satellite cloud winds over oceanic regions  

NASA Technical Reports Server (NTRS)

A five year aircraft experiment to verify the quality of satellite cloud winds over oceans using in situ aircraft inertial navigation system wind measurements is presented. The final results show that satellite measured cumulus cloud motions are very good estimators of the cloud base wind for trade wind and subtropical high regions. The average magnitude of the vector differences between the cloud motion and the cloud base wind is given. For cumulus clouds near frontal regions, the cloud motion agreed best with the mean cloud layer wind. For a very limited sample, cirrus cloud motions also most closely followed the mean wind in the cloud layer.

Hasler, A. F.; Skillman, W. C.

1979-01-01

56

Temporal prediction of block motion vectors with local ambiguity-based adaptivity  

NASA Astrophysics Data System (ADS)

The computational burden of full search block matching algorithms for motion estimation in video coding can be reduced through exploitation of spatial and temporal correlation of the motion vectors. This paper describes a simple adaptive temporal prediction scheme for block motion vectors. The first-order temporal predictor determines the center of the search area for a conventional block match, but with substantially reduced search radius. The abbreviated search reduces computation by about 75% for blocks whose motion is successfully predicted. Adaptivity is introduced through the notion of ambiguity in the predicted block match. Those blocks whose matching cost function shows too great an ambiguity in the neighborhood of the best match are instead estimated by the conventional full search. While performance of the algorithm is dependent on sequence content, it offers an attractive choice in the computational cost/performance tradeoff for simple motion compensation.

O'Halek, Stephen; Sauer, Ken D.

1994-09-01

57

University Navstar Consortium GPS Site Motion Vector/Crustal Velocity Archive  

NSDL National Science Digital Library

The University Navstar Consortium (UNAVCO) Boulder facility has developed a Global Positioning System (GPS) Site Motion Vector Archive. Precise motions of points on the Earth, made with continuous or episodic GPS measurements, are being used to study tectonic processes including plate motions, plate boundary zone deformation, earthquakes, and volcanic eruptions. This archive of GPS velocities contains project information, maps, links, data, and metadata from both regional and global GPS analyses and showcases the work conducted by university and other research investigators. The archive also contains a global plate motion model velocity calculator and an interactive map tool. Velocity data are also accessible via a Distributed Ocean Data Sets (DODS) server.

Meertens, Charles

2001-03-23

58

Turbulent fluid motion 2: Scalars, vectors, and tensors  

NASA Technical Reports Server (NTRS)

The author shows that the sum or difference of two vectors is a vector. Similarly the sum of any two tensors of the same order is a tensor of that order. No meaning is attached to the sum of tensors of different orders, say u(sub i) + u(sub ij); that is not a tensor. In general, an equation containing tensors has meaning only if all the terms in the equation are tensors of the same order, and if the same unrepeated subscripts appear in all the terms. These facts will be used in obtaining appropriate equations for fluid turbulence. With the foregoing background, the derivation of appropriate continuum equations for turbulence should be straightforward.

Deissler, Robert G.

1991-01-01

59

Retrieving microphysical properties and air motion of cirrus clouds based on the doppler moments method using cloud radar  

NASA Astrophysics Data System (ADS)

Radar parameters including radar reflectivity, Doppler velocity, and Doppler spectrum width were obtained from Doppler spectrum moments. The Doppler spectrum moment is the convolution of both the particle spectrum and the mean air vertical motion. Unlike strong precipitation, the motion of particles in cirrus clouds is quite close to the air motion around them. In this study, a method of Doppler moments was developed and used to retrieve cirrus cloud microphysical properties such as the mean air vertical velocity, mass-weighted diameter, effective particle size, and ice content. Ice content values were retrieved using both the Doppler spectrum method and classic Z-IWC (radar reflectivity-ice water content) relationships; however, the former is a more reasonable method.

Zhong, Lingzhi; Liu, Liping; Deng, Min; Zhou, Xiuji

2012-05-01

60

Arctic PBL Cloud Height and Motion Retrievals from MISR and MINX  

NASA Technical Reports Server (NTRS)

How Arctic clouds respond and feedback to sea ice loss is key to understanding of the rapid climate change seen in the polar region. As more open water becomes available in the Arctic Ocean, cold air outbreaks (aka. off-ice flow from polar lows) produce a vast sheet of roll clouds in the planetary boundary layer (PBl). The cold air temperature and wind velocity are the critical parameters to determine and understand the PBl structure formed under these roll clouds. It has been challenging for nadir visible/IR sensors to detect Arctic clouds due to lack of contrast between clouds and snowy/icy surfaces. In addition) PBl temperature inversion creates a further problem for IR sensors to relate cloud top temperature to cloud top height. Here we explore a new method with the Multiangle Imaging Spectro-Radiometer (MISR) instrument to measure cloud height and motion over the Arctic Ocean. Employing a stereoscopic-technique, MISR is able to measure cloud top height accurately and distinguish between clouds and snowy/icy surfaces with the measured height. We will use the MISR INteractive eXplorer (MINX) to quantify roll cloud dynamics during cold-air outbreak events and characterize PBl structures over water and over sea ice.

Wu, Dong L.

2012-01-01

61

Stratiform clouds and their interaction with atmospheric motion  

NASA Technical Reports Server (NTRS)

The spatial patterns of stratocumulus cloud frequency for the continental United States and adjacent oceans were routinely obtained from surface cloud observations every six hours. These frequencies were correlated with upper air patterns at 850, 700, and 500 mb. Significant frequency maxima were found near trough axes over marine areas during relatively stationary large-scale wave patterns. These maxima tended to occur to the east of trough axes. Over continental regions, there was little relationship between stratocumulus and synoptic-scale flows patterns, probably because of the short lifetime of cloud over land. A summary of these findings is included.

Clark, John H. E.; Shirer, Hampton N.

1993-01-01

62

Adaptive quarter-pel motion estimation and motion vector coding algorithm for the H.264/AVC standard  

NASA Astrophysics Data System (ADS)

We present an adaptive quarter-pel (Qpel) motion estimation (ME) method for H.264/AVC. Instead of applying Qpel ME to all macroblocks (MBs), the proposed method selectively performs Qpel ME in an MB level. In order to reduce the bit rate, we also propose a motion vector (MV) encoding technique that adaptively selects a different variable length coding (VLC) table according to the accuracy of the MV. Experimental results show that the proposed method can achieve about 3% average bit rate reduction.

Jung, Seung-Won; Park, Chun-Su; Ha, Le Thanh; Ko, Sung-Jea

2009-11-01

63

Registration of motion-distorted interlaced images captured by a scanning vector imaging sensor  

NASA Astrophysics Data System (ADS)

We present an algorithm to realign images distorted by motion and vibrations captured in cameras that use a scanning vector sensor with an interlaced scheme. In particular, the method is developed for images captured by a staggered time delay and integration camera distorted by motion. The algorithm improves the motion-distorted image by adjusting its fields irrespective of the type of motion that occurs during the exposure. The algorithm performs two tasks: estimation of the field relative motion during the exposure by a normal least-squares estimation technique and improvement of the degraded image from such motion distortion. The algorithm uses matrix computations; therefore it has a computation advantage over algorithms based on the technique of searching for a match. The algorithm is successfully demonstrated on both simulated and real images.

Avrin, A.; Stern, A.; Kopeika, N. S.

2006-08-01

64

PROPER-MOTION STUDY OF THE MAGELLANIC CLOUDS USING SPM MATERIAL  

SciTech Connect

Absolute proper motions are determined for stars and galaxies to V = 17.5 over a 450 deg{sup 2} area that encloses both Magellanic Clouds. The proper motions are based on photographic and CCD observations of the Yale/San Juan Southern Proper Motion program, which span a baseline of 40 years. Multiple, local relative proper-motion measures are combined in an overlap solution using photometrically selected Galactic disk stars to define a global relative system that is then transformed to absolute using external galaxies and Hipparcos stars to tie into the ICRS. The resulting catalog of 1.4 million objects is used to derive the mean absolute proper motions of the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC); ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}){sub LMC} = (1.89, + 0.39) {+-} (0.27, 0.27) masyr{sup -1} and ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}){sub SMC} = (0.98, - 1.01) {+-} (0.30, 0.29) masyr{sup -1}. These mean motions are based on best-measured samples of 3822 LMC stars and 964 SMC stars. A dominant portion (0.25 mas yr{sup -1}) of the formal errors is due to the estimated uncertainty in the inertial system of the Hipparcos Catalog stars used to anchor the bright end of our proper motion measures. A more precise determination can be made for the proper motion of the SMC relative to the LMC; ({mu}{sub {alpha}cos {delta}}, {mu}{sub {delta}}){sub SMC-LMC} = (-0.91, - 1.49) {+-} (0.16, 0.15) masyr{sup -1}. This differential value is combined with measurements of the proper motion of the LMC taken from the literature to produce new absolute proper-motion determinations for the SMC, as well as an estimate of the total velocity difference of the two clouds to within {+-}54 km s{sup -1}. The absolute proper-motion results are consistent with the Clouds' orbits being marginally bound to the Milky Way, albeit on an elongated orbit. The inferred relative velocity between the Clouds places them near their binding energy limit and, thus, no definitive conclusion can be made as to whether or not the Clouds are bound to one another.

Vieira, Katherine; Girard, Terrence M.; Van Altena, William F.; Casetti-Dinescu, Dana I.; Korchagin, Vladimir I.; Herrera, David, E-mail: kvieira@cida.v, E-mail: terry.girard@yale.ed, E-mail: william.vanaltena@yale.ed [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

2010-12-15

65

Proper-motion Study of the Magellanic Clouds Using SPM Material  

NASA Astrophysics Data System (ADS)

Absolute proper motions are determined for stars and galaxies to V = 17.5 over a 450 deg2 area that encloses both Magellanic Clouds. The proper motions are based on photographic and CCD observations of the Yale/San Juan Southern Proper Motion program, which span a baseline of 40 years. Multiple, local relative proper-motion measures are combined in an overlap solution using photometrically selected Galactic disk stars to define a global relative system that is then transformed to absolute using external galaxies and Hipparcos stars to tie into the ICRS. The resulting catalog of 1.4 million objects is used to derive the mean absolute proper motions of the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC); (??cos ?, ??)LMC = (1.89, + 0.39) ± (0.27, 0.27) masyr-1 and (??cos ?, ??)SMC = (0.98, - 1.01) ± (0.30, 0.29) masyr-1. These mean motions are based on best-measured samples of 3822 LMC stars and 964 SMC stars. A dominant portion (0.25 mas yr-1) of the formal errors is due to the estimated uncertainty in the inertial system of the Hipparcos Catalog stars used to anchor the bright end of our proper motion measures. A more precise determination can be made for the proper motion of the SMC relative to the LMC; (??cos ?, ??)SMC-LMC = (-0.91, - 1.49) ± (0.16, 0.15) masyr-1. This differential value is combined with measurements of the proper motion of the LMC taken from the literature to produce new absolute proper-motion determinations for the SMC, as well as an estimate of the total velocity difference of the two clouds to within ±54 km s-1. The absolute proper-motion results are consistent with the Clouds' orbits being marginally bound to the Milky Way, albeit on an elongated orbit. The inferred relative velocity between the Clouds places them near their binding energy limit and, thus, no definitive conclusion can be made as to whether or not the Clouds are bound to one another.

Vieira, Katherine; Girard, Terrence M.; van Altena, William F.; Zacharias, Norbert; Casetti-Dinescu, Dana I.; Korchagin, Vladimir I.; Platais, Imants; Monet, David G.; López, Carlos E.; Herrera, David; Castillo, Danilo J.

2010-12-01

66

Colour Object recognition combining Motion Descriptors, Zernike Moments and Support Vector Machine  

Microsoft Academic Search

Fourier descriptors have been used successfully in the past to grey-level images, rigid bodied object. Here we used motion descriptors (MD) introduced recently by Gauthier et al., combined with Zernike Moments (ZM), in order to perform a recognition task in colour images. The feature vector for the MD obtained for each object appears to be unique and can be used

Fethi SMACH; Cédric LEMAITRE; Johel MITERAN; Jean Paul GAUTHIER; Mohamed ABID

2006-01-01

67

A point cloud segmentation method based on vector estimation and color clustering  

Microsoft Academic Search

For automatic processing of point clouds, the segmentation is a key but difficult step. Many researchers have tried to develop segmentation methods including edge-based segmentation, surface-based segmentation and color-based segmentation, and so on. In this paper, we present a point data segmentation method based on normal vector estimation and color clustering. The main workflow of this method is made by

Qingming Zhan; Liang Yu; Yubing Liang

2010-01-01

68

Edge Block Detection and Motion Vector Information Based Fast VBSME Algorithm  

NASA Astrophysics Data System (ADS)

Compared with previous standards, H. 264/AVC adopts variable block size motion estimation (VBSME) and multiple reference frames (MRF) to improve the video quality. Full search motion estimation algorithm (FS), which calculates every search candidate in the search window for 7 block type with multiple reference frames, consumes massive computation power. Mathematical analysis reveals that the aliasing problem of subsampling algorithm comes from high frequency signal components. Moreover, high frequency signal components are also the main issues that make MRF algorithm essential. As we know, a picture being rich of texture must contain lots of high frequency signals. So based on these mathematical investigations, two fast VBSME algorithms are proposed in this paper, namely edge block detection based subsampling method and motion vector based MRF early termination algorithm. Experiments show that strong correlation exists among the motion vectors of those blocks belonging to the same macroblock. Through exploiting this feature, a dynamically adjustment of the search ranges of integer motion estimation is proposed in this paper. Combing our proposed algorithms with UMHS almost saves 96-98% Integer Motion Estimation (IME) time compared to the exhaustive search algorithm. The induced coding quality loss is less than 0.8% bitrate increase or 0.04dB PSNR decline on average.

Liu, Qin; Huang, Yiqing; Goto, Satoshi; Ikenaga, Takeshi

69

Earthquake slip vectors and estimates of present-day plate motions  

NASA Technical Reports Server (NTRS)

Two alternative models for present-day global plate motions are derived from subsets of the NUVEL-1 data in order to investigate the degree to which earthquake slip vectors affect the NUVEL-1 model and to provide estimates of present-day plate velocities that are independent of earthquake slip vectors. The data set used to derive the first model excludes subduction zone slip vectors. The primary purpose of this model is to demonstrate that the 240 subduction zone slip vectors in the NUVEL-1 data set do not greatly affect the plate velocities predicted by NUVEL-1. A data set that excludes all of the 724 earthquake slip vectors used to derive NUVEL-1 is used to derive the second model. This model is suitable as a reference model for kinematic studies that require plate velocity estimates unaffected by earthquake slip vectors. The slip-dependent slip vector bias along transform faults is investigated using the second model, and evidence is sought for biases in slip directions along spreading centers.

Demets, Charles

1993-01-01

70

Integration of Multiple Motion Vectors Over Space: An fMRI Study of Transparent Motion Perception  

Microsoft Academic Search

Visual scenes are frequently composed of objects that move in different directions. To segment such scenes into distinct objects or image planes, local motion cues have to be evaluated and integrated according to criteria of global coherence. When several populations of coherently moving random dots penetrate each other, the visual system tends to assign them to different planes—perceived as transparent

Lars Muckli; Wolf Singer; Friedhelm E. Zanella; Rainer Goebel

2002-01-01

71

A Convective Vorticity Vector Associated With Tropical Convection: A 2D Cloud-Resolving Modeling Study  

NASA Technical Reports Server (NTRS)

Although dry/moist potential vorticity is a useful physical quantity for meteorological analysis, it cannot be applied to the analysis of 2D simulations. A convective vorticity vector (CVV) is introduced in this study to analyze 2D cloud-resolving simulation data associated with 2D tropical convection. The cloud model is forced by the vertical velocity, zonal wind, horizontal advection, and sea surface temperature obtained from the TOGA COARE, and is integrated for a selected 10-day period. The CVV has zonal and vertical components in the 2D x-z frame. Analysis of zonally-averaged and mass-integrated quantities shows that the correlation coefficient between the vertical component of the CVV and the sum of the cloud hydrometeor mixing ratios is 0.81, whereas the correlation coefficient between the zonal component and the sum of the mixing ratios is only 0.18. This indicates that the vertical component of the CVV is closely associated with tropical convection. The tendency equation for the vertical component of the CVV is derived and the zonally-averaged and mass-integrated tendency budgets are analyzed. The tendency of the vertical component of the CVV is determined by the interaction between the vorticity and the zonal gradient of cloud heating. The results demonstrate that the vertical component of the CVV is a cloud-linked parameter and can be used to study tropical convection.

Gao, Shou-Ting; Ping, Fan; Li, Xiao-Fan; Tao, Wei-Kuo

2004-01-01

72

Cometary cloud in the solar system and the Resibois--Prigogine singular invariants of motion  

SciTech Connect

A relation between nonintegrability of nonlinear dynamical systems with a continuous Fourier spectrum and irreversibility is investigated in terms of the Lie-algebraic formalism. Resibois and Prigogine's singular invariants of motion play an essential role. As an application of the formalism, we solve the restricted three-body problem for the case of nearly parabolic motion of the third body. This gives a model of the motion of a comet in the solar system. The results indicate that there is (deterministic) chaos in the motion of a comet in a nearly parabolic orbit. A possible physical implication of the chaotic motion is the existence of a cometary cloud surrounding the solar system. The theoretical results are compared with numerical results, and show good agreement.

Petrosky, T.Y.

1987-09-01

73

Stratiform clouds and their interaction with atmospheric motion  

NASA Technical Reports Server (NTRS)

During 1989 and 1990, the researchers saw the publication of two papers and the submission of a third for review on work supported primarily by the previous contract, NAS8-36150; the delivery of an invited talk at the SIAM Conference on Dynamical Systems in Orlando, Florida; and the start of two new projects on the radiative effects of stratocumulus on the large-scale flow. The published papers discuss aspects of stratocumulus circulations (Laufersweiler and Shirer, 1989) and the Hadley to Rossby regime transition in rotating spherical systems (Higgins and Shirer, 1990). The submitted paper (Haack and Shirer, 1990) discusses a new nonlinear model of roll circulations that are forced both dynamically and thermally. The invited paper by H. N. Shirer and R. Wells presented an objective means for determining appropriate truncation levels for low-order models of flows involving two incommensurate periods; this work has application to the Hadley to Rossby transition problem in quasi-geostrophic flows (Moroz and Holmes, 1984). The new projects involve the development of a multi-layered quasi-geostrophic channel model for study of the modulation of the large-scale flow by stratocumulus clouds that typically develop off the coasts of continents. In this model the diabatic forcing in the lowest layer will change in response to the (parameterized) development of extensive fields of stratocumulus clouds. To guide creation of this parameterization scheme, researchers are producing climatologies of stratocumulus frequency and the authors correlate these frequencies with the phasing and amplitude of the large-scale flow pattern. Researchers discuss the above topics in greater detail.

Clark, John H. E.; Shirer, Hampton N.

1990-01-01

74

Noninvasive evaluation of contractile behavior of cardiomyocyte monolayers based on motion vector analysis.  

PubMed

A noninvasive method for the characterization of cardiomyocyte contractile behavior is presented. Light microscopic video images of cardiomyocytes were captured with a high-speed camera, and motion vectors (which have a velocity dimension) were calculated with a high spatiotemporal resolution using a block-matching algorithm. This method could extract contraction and relaxation motions of cardiomyocytes separately and evaluate characteristics such as the beating rate, orientation of contraction, beating cooperativity/homogeneity in the monolayer, and wave propagation of impulses. Simultaneous phase-contrast imaging and calcium (Ca2+) fluorescence measurements confirmed that the timing of the maximum shortening velocity of cardiomyocytes correlated well with intracellular Ca2+ transients. Based on our analysis, gap junction inhibitors, 1-heptanol (2?mM) or 18-?-glycyrrhetinic acid (30??M), resulted in clear changes in beating cooperativity and the propagation pattern of impulses in the cardiomyocyte monolayer. Additionally, the time dependence of the motion vector length indicated a prolonged relaxation process in the presence of potassium (K+) channel blockers, dl-sotalol (1??M), E-4031 (100?nM), or terfenadine (100?nM), reflecting the prolonged QT (Q wave and T wave) interval of cardiomyocytes. Effects of autonomic agents (acetylcholine or epinephrine [EPI]) or EPI and propranolol on cardiomyocytes were clearly detected by the alterations of beating rate and the motion vector length in contraction and relaxation processes. This method was noninvasive and could sensitively evaluate the contractile behavior of cardiomyocytes; therefore, it may be used to study and/or monitor cardiomyocyte tissue during prolonged culture periods and in screens for drugs that may alter the contraction of cardiomyocytes. PMID:21851323

Hayakawa, Tomohiro; Kunihiro, Takeshi; Dowaki, Suguru; Uno, Hatsume; Matsui, Eriko; Uchida, Masashi; Kobayashi, Seiji; Yasuda, Akio; Shimizu, Tatsuya; Okano, Teruo

2012-01-01

75

Transverse motion of high-speed barium clouds in the ionosphere  

NASA Technical Reports Server (NTRS)

Simulation results, based on a field-line-integrated, two-dimensional, electrostatic model, are presented for the motion of a barium cloud injected transverse to the geomagnetic field in the ionosphere at high speeds. It is found that the gross evaluation of injected plasma clouds depends on the initial conditions, as well as the nature of the background coupling. For a massive (mass of about 10 kg), orbital (velocity of about 5 km/s) release in the F region (350-450 km), it is found that plasma clouds can drift tens of kilometers across the magnetic field in tens of seconds after ionization. This type of release is similar to those which are planned for the Combined Release and Radiation Effects Satellite mission.

Mitchell, H. G., Jr.; Fedder, J. A.; Huba, J. D.; Zalesak, S. T.

1985-01-01

76

Dipole–dipole induced global motion of Rydberg-dressed atom clouds  

NASA Astrophysics Data System (ADS)

We consider two clouds of ground-state alkali atoms in two distinct hyperfine ground states. Each level is far off-resonantly coupled to a Rydberg state, which leads to dressed ground states with a weak admixture of the Rydberg state properties. Due to this admixture, for a proper choice of the Rydberg states, the atoms experience resonant dipole–dipole interactions that induce mechanical forces acting on all atoms within both clouds. This behaviour is in contrast to the dynamics predicted for bare dipole–dipole interactions between Rydberg superatoms, where only a single atom per cloud is subject to dipole–dipole induced motion (Möbius et al 2013 Phys. Rev. A 88 012716).

Genkin, M.; Wüster, S.; Möbius, S.; Eisfeld, A.; Rost, J. M.

2014-05-01

77

Characterizing uncertainty in the motion, future location and ash concentrations of volcanic plumes and ash clouds  

NASA Astrophysics Data System (ADS)

Forecasting the location and airborne concentrations of volcanic ash plumes and their dispersing clouds is complex and knowledge of the uncertainty in these forecasts is critical to assess and mitigate the hazards that could exist. We show the results from an interdisciplinary project that brings together scientists drawn from the atmospheric sciences, computer science, engineering, mathematics, and geology. The project provides a novel integration of computational and statistical modeling with a widely-used volcanic particle dispersion code, to provide quantitative measures of confidence in predictions of the motion of ash clouds caused by volcanic eruptions. We combine high performance computing and stochastic analysis, resulting in real time predictions of ash cloud motion that account for varying wind conditions and a range of model variables. We show how coupling a real-time model for ash dispersal, PUFF, with a volcanic eruption model, BENT, allows for the definition of the variability in the dispersal model inputs and hence classify the uncertainty that can then propagate for the ash cloud location and downwind concentrations. We additionally analyze the uncertainty in the numerical weather prediction forecast data used by the dispersal model by using ensemble forecasts and assess how this affects the downwind concentrations. These are all coupled together and by combining polynomical chaos quadrature with stochastic integration techniques, we provide a quantitative measure of the reliability (i.e. error) of those predictions. We show comparisons of the downwind height calculations and mass loadings with observations of ash clouds available from satellite remote sensing data. The aim is to provide a probabilistic forecast of location and ash concentration that can be generated in real-time and used by those end users in the operational ash cloud hazard assessment environment.

Webley, P.; Patra, A. K.; Bursik, M. I.; Pitman, E. B.; Dehn, J.; Singh, T.; Singla, P.; Stefanescu, E. R.; Madankan, R.; Pouget, S.; Jones, M.; Morton, D.; Pavolonis, M. J.

2013-12-01

78

Motion compensation by block matching and vector postprocessing in subband coding of TV signals at 15 Mbit/s  

NASA Astrophysics Data System (ADS)

This work deals with a new coding method for transmitting TV signals at 15 Mbit/s. The coding scheme is based upon sub-band decomposition by Pseudo-QMF filtering and motion compensation. In that context we have studied the influence on the overall system of various strategies in the motion compensation block. More precisely, in the case of a motion compensation by block matching, the influence of overlapping between the blocks has been first considered. A new non-linear post processing scheme of the displacement vector is also presented which smoothed pretty well the vector field and reduced significantly the vector coding bit rate. Finally various methods of vector coding have been designed and compared.

Lallauret, Fabrice; Barba, Dominique

1991-11-01

79

Radial Hermite Operators for Scattered Point Cloud Data with Normal Vectors and Applications to Implicitizing Polygon Mesh Surfaces for Generalized CSG Operations and Smoothing  

Microsoft Academic Search

We describe a new technique for fitting scattered point cloud data. Given a scattered point cloud of 3D data points and associated normal vectors, our new method produces an implicit volume model whose zero level isosurface interpolates the given points and associated normal vectors. In this paper, we concentrate on certain application of these new volume modeling techniques. We take

Gregory M. Nielson

2004-01-01

80

Feature extraction and wall motion classification of 2D stress echocardiography with support vector machines  

NASA Astrophysics Data System (ADS)

Stress echocardiography is a common clinical procedure for diagnosing heart disease. Clinically, diagnosis of the heart wall motion depends mostly on visual assessment, which is highly subjective and operator-dependent. Introduction of automated methods for heart function assessment have the potential to minimise the variance in operator assessment. Automated wall motion analysis consists of two main steps: (i) segmentation of heart wall borders, and (ii) classification of heart function as either "normal" or "abnormal" based on the segmentation. This paper considers automated classification of rest and stress echocardiography. Most previous approaches to the classification of heart function have considered rest or stress data separately, and have only considered using features extracted from the two main frames (corresponding to the end-of-diastole and end-of-systole). One previous attempt [1] has been made to combine information from rest and stress sequences utilising a Hidden Markov Model (HMM), which has proven to be the best performing approach to date. Here, we propose a novel alternative feature selection approach using combined information from rest and stress sequences for motion classification of stress echocardiography, utilising a Support Vector Machines (SVM) classifier. We describe how the proposed SVM-based method overcomes difficulties that occur with HMM classification. Overall accuracy with the new method for global wall motion classification using datasets from 173 patients is 92.47%, and the accuracy of local wall motion classification is 87.20%, showing that the proposed method outperforms the current state-of-the-art HMM-based approach (for which global and local classification accuracy is 82.15% and 78.33%, respectively).

Chykeyuk, Kiryl; Clifton, David A.; Noble, J. Alison

2011-03-01

81

The primer vector in linear, relative-motion equations. [spacecraft trajectory optimization  

NASA Technical Reports Server (NTRS)

Primer vector theory is used in analyzing a set of linear, relative-motion equations - the Clohessy-Wiltshire equations - to determine the criteria and necessary conditions for an optimal, N-impulse trajectory. Since the state vector for these equations is defined in terms of a linear system of ordinary differential equations, all fundamental relations defining the solution of the state and costate equations, and the necessary conditions for optimality, can be expressed in terms of elementary functions. The analysis develops the analytical criteria for improving a solution by (1) moving any dependent or independent variable in the initial and/or final orbit, and (2) adding intermediate impulses. If these criteria are violated, the theory establishes a sufficient number of analytical equations. The subsequent satisfaction of these equations will result in the optimal position vectors and times of an N-impulse trajectory. The solution is examined for the specific boundary conditions of (1) fixed-end conditions, two-impulse, and time-open transfer; (2) an orbit-to-orbit transfer; and (3) a generalized rendezvous problem. A sequence of rendezvous problems is solved to illustrate the analysis and the computational procedure.

1980-01-01

82

Cloud shadow speed sensor  

NASA Astrophysics Data System (ADS)

Changing cloud cover is a major source of solar radiation variability and poses challenges for the integration of solar energy. A compact and economical system is presented that measures cloud shadow motion vectors to estimate power plant ramp rates and provide short-term solar irradiance forecasts. The cloud shadow speed sensor (CSS) is constructed using an array of luminance sensors and a high-speed data acquisition system to resolve the progression of cloud passages across the sensor footprint. An embedded microcontroller acquires the sensor data and uses a cross-correlation algorithm to determine cloud shadow motion vectors. The CSS was validated against an artificial shading test apparatus, an alternative method of cloud motion detection from ground-measured irradiance (linear cloud edge, LCE), and a UC San Diego sky imager (USI). The CSS detected artificial shadow directions and speeds to within 15° and 6% accuracy, respectively. The CSS detected (real) cloud shadow directions and speeds with average weighted root-mean-square difference of 22° and 1.9 m s-1 when compared to USI and 33° and 1.5 m s-1 when compared to LCE results.

Fung, V.; Bosch, J. L.; Roberts, S. W.; Kleissl, J.

2014-06-01

83

CLOUDS.  

National Technical Information Service (NTIS)

This report is an in-depth Users Manual for the ANSI FORTRAN computer program CLOUDS. CLOUDS is designed in two major blocks: cloud field generation and cloud-free line-of-sight (CFLOS) calculation. The cloud field generation block models observed cloud f...

M. K. Seager

1979-01-01

84

Non-drifting limb angle measurement relative to the gravitational vector during dynamic motions using accelerometers and rate gyros  

Microsoft Academic Search

A method for estimating limb orientation, during static, quasi-static, and dynamic motions, by using a combination of gyroscopes and accelerometers is presented. The method uses two tri-axis accelerometers and one single axis rate gyro to calculate an estimate of angle relative to the gravitational vector independently from the rotational accelerations. This unbiased inclination estimate is blended with the angular velocity

Andrew J. Petruska; Sanford G. Meek

2011-01-01

85

Non-drifting limb angle measurement relative to the gravitational vector during dynamic motions using accelerometers and rate gyros  

Microsoft Academic Search

A method for estimating limb orientation, during static, quasi-static, and dynamic motions, by using a combina- tion of gyroscopes and accelerometers is presented. The method uses two tri-axis accelerometers and one single axis rate gyro to calculate an estimate of angle relative to the gravitational vector independently from the rotational accelerations. This unbiased inclination estimate is blended with the angular

Andrew J. Petruska; Sanford G. Meek

2011-01-01

86

Comparison of General Relativistic and Pseudo-Newtonian Description of Magellanic-Clouds Motion in the Field of Milky way  

NASA Astrophysics Data System (ADS)

We test precision of the Cosmological Paczynski-Wiita (CPW) potential reflecting properties of the Schwarzschild-de Sitter (SdS) spacetimes in modeling dynamical phenomena related to galaxy motion. We consider a simplified model of Magellanic Clouds moving in the field of Milky Way as test particles. Time evolution of their position along trajectories obtained in the CPW framework using the notion of Newtonian time is compared to the one obtained in the fully general relativistic (GR) approach when the time evolution is expressed in terms of time related to the location of Earth in the Galaxy field. The differences in the position-evolution of the Magellanic Clouds obtained in the CPW and GR approaches are given for appropriately chosen values of the Milky Way mass. It is shown that the integrated relativistic corrections represent 10-5 part of the Newtonian CPW predictions for the orbital characteristics of the motion and slightly grow with Galaxy mass growing, being at least by one order higher than the local scaling GR corrections. The integrated orbital GR corrections thus could be important only in very precise modeling of the motion of Magellanic Clouds. The CPW framework is used to show that, quite surprisingly, the influence of the cosmological constant on the Magellanic Clouds motion can be strong and significantly alters the trajectories of Magellanic Clouds and time evolution along them. The relative contribution of the cosmological constant is 10-1 or higher. It is most profoundly demonstrated by the increase of the binding mass that represents 22% for Small Magellanic Cloud and even 47% for Large Magellanic Cloud, putting serious doubts on gravitational binding to the Milky Way in the later case.

Stuchlík, Zden?k; Schee, Jan

2012-04-01

87

ON THE INTERPRETATION OF RECENT PROPER MOTION DATA FOR THE LARGE MAGELLANIC CLOUD  

SciTech Connect

Recent observational studies using the Hubble Space Telescope have derived the center-of-mass proper motion (CMPM) of the Large Magellanic Cloud (LMC). Although these studies carefully treated both rotation and perspective effects in deriving the proper motion (PM) for each of the sampled fields, they did not consider the effects of local random motion in the derivation. This means that the average PM of the fields (i.e., the observed CMPM) could significantly deviate from the true CMPM, because the effect of local random motion cannot be close to zero in making the average PM for the small number of fields ({approx}10). We discuss how significantly the observationally derived CMPM can deviate from the true CMPM by applying the same method as used in the observations for a dynamical model of the LMC with a known true CMPM. We find that the deviation can be as large as {approx}50 km s{sup -1} ({approx}0.21 mas yr{sup -1}), if the LMC has a thick disk and a maximum circular velocity of {approx}120 km s{sup -1}. We also find that the deviation depends both on the total number of sampled fields and on the structure and kinematics of the LMC. We therefore suggest that there is a possibility that the observed CMPM of the LMC deviates from the true one to some extent. We also show that a simple mean of PM for a large number of LMC fields ({approx}1000) can be much closer to the true CMPM.

Bekki, Kenji [ICRAR, M468, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

2011-03-20

88

vectors  

NSDL National Science Digital Library

The word vector comes from the Latin term vehere, to carry. In Biology, a vector is an agent which carries disease, such as a mosquito carrying infected blood from one patient to the next. In physics, a vector is a quantity which has both a magnitude and a direction associated with it. The most commonly used example of vectors in everyday life is velocity. When you drive your car, your speedometer tells you the speed of your car, but it doesn't tell you where you are going. The combination of both where you are going and how fast you are going there is your car's velocity.

Joiner, David; The Shodor Education Foundation, Inc.

89

Clouds  

NSDL National Science Digital Library

Clouds comprise a wonderful focus for classroom study. They're ubiquitous, ever-changing, scientifically interesting and, most importantly for teachers, they're cheap. The material presented here includes sections on cloud formation, cloud types, cloud pictures, other cloud-related phenomena, and a glossary.

Wozniak, Carl

90

Real-time prediction of respiratory motion using a cascade structure of an extended Kalman filter and support vector regression  

NASA Astrophysics Data System (ADS)

The motion of thoracic and abdominal tumours induced by respiratory motion often exceeds 20 mm, and can significantly compromise dose conformality. Motion-adaptive radiotherapy aims to deliver a conformal dose distribution to the tumour with minimal normal tissue exposure by compensating for the tumour motion. This adaptive radiotherapy, however, requires the prediction of the tumour movement that can occur over the system latency period. In general, motion prediction approaches can be classified into two groups: model-based and model-free. Model-based approaches utilize a motion model in predicting respiratory motion. These approaches are computationally efficient and responsive to irregular changes in respiratory motion. Model-free approaches do not assume an explicit model of motion dynamics, and predict future positions by learning from previous observations. Artificial neural networks (ANNs) and support vector regression (SVR) are examples of model-free approaches. In this article, we present a prediction algorithm that combines a model-based and a model-free approach in a cascade structure. The algorithm, which we call EKF–SVR, first employs a model-based algorithm (named LCM–EKF) to predict the respiratory motion, and then uses a model-free SVR algorithm to estimate and correct the error of the LCM–EKF prediction. Extensive numerical experiments based on a large database of 304 respiratory motion traces are performed. The experimental results demonstrate that the EKF–SVR algorithm successfully reduces the prediction error of the LCM–EKF, and outperforms the model-free ANN and SVR algorithms in terms of prediction accuracy across lookahead lengths of 192, 384, and 576 ms.

Hong, S.-M.; Bukhari, W.

2014-07-01

91

Real-time prediction of respiratory motion using a cascade structure of an extended Kalman filter and support vector regression.  

PubMed

The motion of thoracic and abdominal tumours induced by respiratory motion often exceeds 20 mm, and can significantly compromise dose conformality. Motion-adaptive radiotherapy aims to deliver a conformal dose distribution to the tumour with minimal normal tissue exposure by compensating for the tumour motion. This adaptive radiotherapy, however, requires the prediction of the tumour movement that can occur over the system latency period. In general, motion prediction approaches can be classified into two groups: model-based and model-free. Model-based approaches utilize a motion model in predicting respiratory motion. These approaches are computationally efficient and responsive to irregular changes in respiratory motion. Model-free approaches do not assume an explicit model of motion dynamics, and predict future positions by learning from previous observations. Artificial neural networks (ANNs) and support vector regression (SVR) are examples of model-free approaches. In this article, we present a prediction algorithm that combines a model-based and a model-free approach in a cascade structure. The algorithm, which we call EKF-SVR, first employs a model-based algorithm (named LCM-EKF) to predict the respiratory motion, and then uses a model-free SVR algorithm to estimate and correct the error of the LCM-EKF prediction. Extensive numerical experiments based on a large database of 304 respiratory motion traces are performed. The experimental results demonstrate that the EKF-SVR algorithm successfully reduces the prediction error of the LCM-EKF, and outperforms the model-free ANN and SVR algorithms in terms of prediction accuracy across lookahead lengths of 192, 384, and 576 ms. PMID:24909152

Hong, S-M; Bukhari, W

2014-07-01

92

The Impact of Satellite Atmospheric Motion Vectors in the GMAO GEOS-5 Global Data Assimilation System  

NASA Technical Reports Server (NTRS)

The impact of satellite-derived atmospheric motion vectors (AMVs) on numerical weather forecasts is examined using the GEOS-5 global atmospheric data assimilation system. Cycling data assimilation experiments, including twice-daily 5-day forecasts, are conducted for two 6-week periods during the 2010 Atlantic hurricane season and 2010-2011Northern Hemisphere winter season. Results from a control experiment that includes all AMVs and other data types assimilated operationally in GEOS-5 are compared with those from an experiment in which the GEOS-5 AMVs (only) are replaced by ones produced by the U. S. Navy?s NAVDAS-AR atmospheric data assimilation system. The Navy AMVs are assimilated in their entirety as well as in various subset combinations. The primary objective of these experiments is to determine whether aspects of the NAVDAS-AR data selection and quality control procedure, especially the use of carefully averaged ("super-ob?) wind vectors and large volume of AMVs, explain the typically larger beneficial impact of these data in the Navy system as compared with most other forecast systems. Adjoint-based observation impact calculations are assessed and compared with traditional metrics such as forecast geopotential height anomaly correlations and observation-minus-forecast departures. Results so far indicate that that the greater number of NRL AMVs is primarily responsible for their larger impact, although superobing also appears to be beneficial. Map views show that the impact obtained from assimilation of the NRL AMVs is more uniformly beneficial, perhaps due to the averaging of individual observations in creating the super-obs. While the NRL AMVs have a much larger impact in GEOS-5 than do the control AMVs, their impact is still smaller than in the Navy forecast system, suggesting that the mix of observations may play an important role in modulating the impact of any one data type. At the same time, reducing the number of satellite radiances assimilated in GEOS-5 does not significantly alter the impact of the AMVs

Gelaro, R. D.; Merkova, D.; Tai, King-Sheng; McCarty, W.

2012-01-01

93

Operational retrieval of cloud-top heights using MISR data  

Microsoft Academic Search

Due to its unique nine-angle configuration, the Multi-angle Imaging SpectroRadiometer (MISR) can retrieve cloud parameters such as cloud-motion vectors and cloud-top heights using a purely geometrical technique that involves locating the same cloud features at different viewing angles. The geometrical nature of this technique means that the retrievals are relatively insensitive to the absolute instrument calibration. Fast stereo-matching algorithms have

Catherine Moroney; Roger Davies; Jan-Peter Muller

2002-01-01

94

Parallel Implementations of Block-Based Motion Vector Estimation for Video Compression on Four Parallel Processing Systems  

Microsoft Academic Search

Parallel algorithms, based on a distributed memory machine model, for an exhaustive search technique for motion vector estimation in video compression are being designed and evaluated. Results from the execution on a 16,384 processor MasPar MP-1 (an SIMD machine), a 140 node Intel Paragon XP\\/S and a 16 node IBM SP2 (two M IMD machines), and the 16 processor PASM

Min Tan; Janet M. Siegel; Howard Jay Siegel

1999-01-01

95

On the bulk motion of the ion clouds formed by the AMPTE solar wind/magnetosheath releases  

SciTech Connect

A principal objective of the Active Magnetospheric Particle Tracer Explorers mission was to release lithium and barium ion clouds that were initially sufficiently mass dense to strongly perturb the ambient solar wind or magnetosheath flow. A key property of these release clouds was that their spatial and temporal scales were smaller than, or of the order of, the Larmor scales of all the ion species involved. A one-dimensional hybrid simulation study conducted by Chapman and Schwartz (1987) showed that momentum could be transferred locally from the oncoming protons to the majority of the release ions, which are associated with the diamagnetic cavity produced by the release, via the quasi-steady boundary layer that forms at the cavity edge. The direction of motion of these snowploughed release ions and the field structure that accelerates them is just that of the oncoming protons. The remainder of the release cloud is photoionized outside of the diamagnetic cavity, and as a consequence of the pickup interaction of these ions in the oncoming proton flow the protons are deflected from their ambient flow direction in the release cloud vicinity. This deflected direction of the oncoming proton flow, just upstream of the snowplough fields, then defines the direction of motion of the snowploughed release ions, which eventually comprise the release ion cloud that is observed from the ground. This transverse component to the direction of the release ion cloud motion suggested by the above simple picture is qualitatively consistent with ground-based observations of the barium releases. Here this simple model for the snowplough dynamics is discussed quantitatively for the particular conditions of the various lithium and barium releases.

Chapman, S.C. (Queen Mary Coll., London (England))

1989-01-01

96

FAST MOTIONS OF GALAXIES IN THE COMA I CLOUD: A CASE OF DARK ATTRACTOR?  

SciTech Connect

We note that nearby galaxies having high negative peculiar velocities are distributed over the sky very inhomogeneously. A part of this anisotropy is caused by the 'Local Velocity Anomaly', i.e., by the bulk motion of nearby galaxies away from the Local Void. However, half of the fast-flying objects reside within a small region known as the Coma I cloud. According to Makarov and Karachentsev, this complex contains 8 groups, 5 triplets, 10 pairs, and 83 single galaxies with a total mass of 4.7 Multiplication-Sign 10{sup 13} M{sub Sun }. We use 122 galaxies in the Coma I region with known distances and radial velocities V{sub LG} < 3000 km s{sup -1} to draw the Hubble relation for them. The Hubble diagram shows a Z-shaped effect of infall with an amplitude of +200 km s{sup -1} on the nearby side and -700 km s{sup -1} on the back side. This phenomenon can be understood as the galaxy infall toward a dark attractor with a mass of {approx}2 Multiplication-Sign 10{sup 14} M{sub Sun} situated at a distance of 15 Mpc from us. The existence of a large void between the Coma and Virgo clusters also probably affects the Hubble flow around the Coma I.

Karachentsev, Igor D.; Nasonova, Olga G. [Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhniy Arkhyz, Karachei-Cherkessia 369167 (Russian Federation); Courtois, Helene M., E-mail: ikar@luna.sao.ru, E-mail: h.courtois@ipnl.in2p3.fr, E-mail: phiruzi@gmail.com [Universite de Lyon, Universite Lyon 1, CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne (France)

2011-12-20

97

Hurricane Debby - An illustration of the complementary nature of VAS soundings and cloud and water vapor motion winds. [Visible Infrared Spin Scan Radiometer Atmospheric Sounder  

NASA Technical Reports Server (NTRS)

The utility of VISSR Atmospheric Sounder (VAS) temperature and moisture soundings and cloud and water vapor motion winds in defining a storm and its surroundings at subsynoptic scales has been examined using a numerical analysis and prognosis system. It is shown that the VAS temperature and moisture data, which specify temperature and moisture well in cloud-free areas, are complemented by cloud and water vapor motion data generated in the cloudy areas. The cloud and water vapor 'winds' provide thermal gradient information for interpolating the soundings across cloudy regions. The loss of analysis integrity due to the reduction of VAS sounding density in the cloudy regions associated with synoptic activity is ameliorated by using cloud and water vapor motion winds. The improvement in numerical forecasts resulting from the addition of these data to the numerical analysis is recorded.

Le Marshall, J. F.; Smith, W. L.; Callan, G. M.

1985-01-01

98

Clouds  

NSDL National Science Digital Library

Students learn about the varieties of clouds, what they look like and how they can affect our lives. Introduction: Have you ever wondered what kind of cloud makes rain, or which one makes fog? Have you ever wondered if there are clouds that mean the weather if going to be good or not? Today, we're going to learn about three different clouds that may ...

Doxey, Ms.

2010-03-26

99

Roll tracking effects of G-vector tilt and various types of motion washout  

NASA Technical Reports Server (NTRS)

In a dogfight scenario, the task was to follow the target's roll angle while suppressing gust disturbances. All subjects adopted the same behavioral strategies in following the target while suppressing the gusts, and the MFP-fitted math model response was generally within one data symbol width. The results include the following: (1) comparisons of full roll motion (both with and without the spurious gravity tilt cue) with the static case. These motion cues help suppress disturbances with little net effect on the visual performance. Tilt cues were clearly used by the pilots but gave only small improvement in tracking errors. (2) The optimum washout (in terms of performance close to real world, similar behavioral parameters, significant motion attenuation (60 percent), and acceptable motion fidelity) was the combined attenuation and first-order washout. (3) Various trends in parameters across the motion conditions were apparent, and are discussed with respect to a comprehensive model for predicting adaptation to various roll motion cues.

Jex, H. R.; Magdaleno, R. E.; Junker, A. M.

1978-01-01

100

Edge Block Detection and Motion Vector Information Based Fast VBSME Algorithm  

Microsoft Academic Search

Compared with previous standards, H. 264\\/AVC adopts variable block size motion estimation (VBSME) and multiple reference frames (MRF) to improve the video quality. Full search motion estimation algorithm (FS), which calculates every search candidate in the search window for 7 block type with multiple reference frames, consumes massive computation power. Mathematical analysis reveals that the aliasing problem of subsampling algorithm

Qin Liu; Yiqing Huang; Satoshi Goto; Takeshi Ikenaga

2008-01-01

101

Simultaneous spectrophotometric determination of nitroaniline isomers after cloud point extraction by using least-squares support vector machines  

NASA Astrophysics Data System (ADS)

Cloud point extraction has been used for the preconcentration of m-nitroaniline, o-nitroaniline and p-nitroaniline and later simultaneous spectrophotometric determination using polyethylene glycol tert-octylphenyl ether (Triton X-100) as surfactant. The resolution of a ternary mixture of the nitroaniline isomers (after extraction by cloud point) by the application of least-squares support vector machines (LS-SVM) was performed. The chemical parameters affecting the separation phase and detection process were studied and optimized. Under the optimum experimental conditions (i.e. pH 7.0, Triton X-100 = 0.6%, equilibrium time 20 min and cloud point 75 °C), calibration graphs were linear in the range of 0.2-20.0, 0.1-15.0 and 0.1-17.0 ?g ml -1 with detection limits of 0.08, 0.05 and 0.06 ?g ml -1 for m-nitroaniline, o-nitroaniline and p-nitroaniline, respectively. The experimental calibration matrix was designed with 21 mixtures of these chemicals. The concentrations were varied between calibration graphs concentrations of nitroaniline isomers. The root mean square error of prediction (RMSEP) for m-nitroaniline, o-nitroaniline and p-nitroaniline were 0.0146, 0.0308 and 0.0304, respectively. This procedure allows the simultaneous determination of nitroaniline isomers in synthetic and real matrix samples good reliability of the determination was proved.

Niazi, Ali; Ghasemi, Jahanbakhsh; Yazdanipour, Ateesa

2007-11-01

102

Primer vector theory applied to the linear relative-motion equations. [for N-impulse space trajectory optimization  

NASA Technical Reports Server (NTRS)

Prime vector theory is used in analyzing a set of linear relative-motion equations - the Clohessy-Wiltshire (C/W) equations - to determine the criteria and necessary conditions for an optimal N-impulse trajectory. The analysis develops the analytical criteria for improving a solution by: (1) moving any dependent or independent variable in the initial and/or final orbit, and (2) adding intermediate impulses. If these criteria are violated, the theory establishes a sufficient number of analytical equations. The subsequent satisfaction of these equations will result in the optimal position vectors and times of an N-impulse trajectory. The solution is examined for the specific boundary conditions of: (1) fixed-end conditions, two impulse, and time-open transfer; (2) an orbit-to-orbit transfer; and (3) a generalized renezvous problem.

Jezewski, D.

1980-01-01

103

Clouds  

NSDL National Science Digital Library

In this scenario-based, problem-based learning (PBL) activity, students investigate cloud formation, cloud classification, and the role of clouds in heating and cooling the Earth; how to interpret TRMM (Tropical Rainfall Measuring Mission) images and data; and the role clouds play in the Earthâs radiant budget and climate. Students assume the role of weather interns in a state climatology office and assist a frustrated student in a homework assignment. Learning is supported by a cloud in a bottle and an ice-albedo demonstration, a three-day cloud monitoring outdoor activity, and student journal assignments. The hands-on activities require two 2-liter soda bottles, an infrared heat lamp, and two thermometers. The resource includes a teacher's guide, questions and answer key, assessment rubric, glossary, and an appendix with information supporting PBL in the classroom.

104

NPS state vector analysis and relative motion plotting software for STS-51  

NASA Astrophysics Data System (ADS)

This thesis outlines the objectives, structure, and operation of the software designed to meet requirements set forth by Development Test Objective 700-6 for the space shuttle Discovery mission STS-51. The primary goals were the comparison of state vector information produced by GPS sources and Discovery's inertial navigation computer, and the real-time display of relative position and rendezvous information between Discovery and a retrievable shuttle pallet satellite. In-flight and postflight examination of GPS and inertial state vectors provided the first step in the development of GPS as an on-orbit navigation system. Analysis of the Orbiter and target satellite state vectors produced real-time graphical displays of operationally significant data to the Discovery's flight crew during rendezvous and proximity operations.

Barker, Lee A.

1994-03-01

105

The relationship between large-scale vertical motion, highly reflective cloud, and sea surface temperature in the tropical Pacific region  

NASA Technical Reports Server (NTRS)

Vertical motion fields at 850 mbar over the tropical Pacific region are calculated from the 1963-1973 mean wind fields for 4 months of the year and for October 1972, the peak month in the 1972-1973 El Nino event. These vertical motion fields are derived using the projective separation technique, which has the unique property of separating vertical motion into components due to meridional wind convergence and zonal wind convergence. This separation permits investigation of the response of the Hadley and Walker circulations to annual and interannual variation of the sea surface temperature in the tropical Pacific. The large-scale features of the computed vertical motion fields are in agreement with those of highly reflective clouds, which indicate the locations of deep convection. Examination of the annual cycle of the vertical motion and its components shows no strong variation of the Walker circulation with the east-west gradient of sea surface temperature. On the other hand, a strong correlation is found between meridional overturning in the eastern Pacific and the local equatorial sea surface temperature: during El Nino events, the eastern and central Pacific contribution to the Hadley circulation tends to increase.

Zimmermann, Peter H.; Newell, Reginald E.; Selkirk, Henry B.

1988-01-01

106

Influence of the cosmic repulsion on the MOND model of the Magellanic Cloud motion in the field of Milky Way  

NASA Astrophysics Data System (ADS)

It has been recently shown that the cosmic repulsion can have a highly significant influence on the motion of Magellanic Clouds (MC) in the gravitational field of Milky Way, treated in the framework of the Cold Dark Matter (CDM) halo model. However, there is an alternative to the CDM halo explanation of the rotation curves in the periphery of spiral galaxies, based on MOdified Newtonian Dynamics (MOND). Therefore, we study the role of the cosmic repulsion in the framework of the MOND theory applied to determine the MC motion. Our results demonstrate that in the MOND framework the influence of the cosmic repulsion on the motion of both Small and Large MC is also highly significant, but it is of a different character than in the framework of the CDM halo model. Moreover, we demonstrate that the MC motion in the framework of the CDM halo and MOND models is subtantially different and can serve as a test of these fundamentally different approaches to the explanation of the phenomena related to galaxies and the motion of satellite galaxies.

Schee, J.; Stuchlík, Z.; Petrásek, M.

2013-12-01

107

THIRD-EPOCH MAGELLANIC CLOUD PROPER MOTIONS. I. HUBBLE SPACE TELESCOPE/WFC3 DATA AND ORBIT IMPLICATIONS  

SciTech Connect

We present proper motions for the Large and Small Magellanic Clouds (LMC and SMC) based on three epochs of Hubble Space Telescope data, spanning a {approx}7 yr baseline, and centered on fields with background QSOs. The first two epochs, the subject of past analyses, were obtained with ACS/HRC, and have been reanalyzed here. The new third epoch with WFC3/UVIS increases the time baseline and provides better control of systematics. The three-epoch data yield proper-motion random errors of only 1%-2% per field. For the LMC this is sufficient to constrain the internal proper-motion dynamics, as will be discussed in a separate paper. Here we focus on the implied center-of-mass proper motions: {mu} {sub W,LMC} = -1.910 {+-} 0.020 mas yr{sup -1}, {mu} {sub N,LMC} = 0.229 {+-} 0.047 mas yr{sup -1}, and {mu} {sub W,SMC} = -0.772 {+-} 0.063 mas yr{sup -1}, {mu} {sub N,SMC} = -1.117 {+-} 0.061 mas yr{sup -1}. We combine the results with a revised understanding of the solar motion in the Milky Way to derive Galactocentric velocities: v {sub tot,LMC} = 321 {+-} 24 km s{sup -1} and v {sub tot,SMC} = 217 {+-} 26 km s{sup -1}. Our proper-motion uncertainties are now dominated by limitations in our understanding of the internal kinematics and geometry of the Clouds, and our velocity uncertainties are dominated by distance errors. Orbit calculations for the Clouds around the Milky Way allow a range of orbital periods, depending on the uncertain masses of the Milky Way and LMC. Periods {approx}< 4 Gyr are ruled out, which poses a challenge for traditional Magellanic Stream models. First-infall orbits are preferred (as supported by other arguments as well) if one imposes the requirement that the LMC and SMC must have been a bound pair for at least several Gyr.

Kallivayalil, Nitya [Yale Center for Astronomy and Astrophysics, 260 Whitney Ave, New Haven, CT 06511 (United States)] [Yale Center for Astronomy and Astrophysics, 260 Whitney Ave, New Haven, CT 06511 (United States); Van der Marel, Roeland P.; Anderson, Jay [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)] [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Besla, Gurtina [Columbia Astrophysics Laboratory, 1027 Pupin Hall, MC 5247, New York, NY 10027 (United States)] [Columbia Astrophysics Laboratory, 1027 Pupin Hall, MC 5247, New York, NY 10027 (United States); Alcock, Charles, E-mail: nitya.kallivayalil@yale.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-02-20

108

Fourier Transform Ion Cyclotron Resonance Mass Resolution and Dynamic Range Limits Calculated by Computer Modeling of Ion Cloud Motion  

NASA Astrophysics Data System (ADS)

Particle-in-Cell (PIC) ion trajectory calculations provide the most realistic simulation of Fourier transform ion cyclotron resonance (FT-ICR) experiments by efficient and accurate calculation of the forces acting on each ion in an ensemble (cloud), including Coulomb interactions (space charge), the electric field of the ICR trap electrodes, image charges on the trap electrodes, the magnetic field, and collisions with neutral gas molecules. It has been shown recently that ion cloud collective behavior is required to generate an FT-ICR signal and that two main phenomena influence mass resolution and dynamic range. The first is formation of an ellipsoidal ion cloud (termed "condensation") at a critical ion number (density), which facilitates signal generation in an FT-ICR cell of arbitrary geometry because the condensed cloud behaves as a quasi-ion. The second phenomenon is peak coalescence. Ion resonances that are closely spaced in m/z coalesce into one resonance if the ion number (density) exceeds a threshold that depends on magnetic field strength, ion cyclotron radius, ion masses and mass difference, and ion initial spatial distribution. These two phenomena decrease dynamic range by rapid cloud dephasing at small ion density and by cloud coalescence at high ion density. Here, we use PIC simulations to quantitate the dependence of coalescence on each critical parameter. Transitions between independent and coalesced motion were observed in a series of the experiments that systematically varied ion number, magnetic field strength, ion radius, ion m/z, ion m/z difference, and ion initial spatial distribution (the present simulations begin from elliptically-shaped ion clouds with constant ion density distribution). Our simulations show that mass resolution is constant at a given magnetic field strength with increasing ion number until a critical value (N) is reached. N dependence on magnetic field strength, cyclotron radius, ion mass, and difference between ion masses was determined for two ion ensembles of different m/z, equal abundance, and equal cyclotron radius. We find that N and dynamic range depend quadratically on magnetic field strength in the range 1-21 Tesla. Dependences on cyclotron radius and ? m/z are linear. N depends on m/z as ( m/z)-2. Empirical expressions for mass resolution as a function of each of the experimental parameters are presented. Here, we provide the first exposition of the origin and extent of trade-off between FT-ICR MS dynamic range and mass resolution (defined not as line width, but as the separation between the most closely resolved masses).

Vladimirov, Gleb; Hendrickson, Christopher L.; Blakney, Greg T.; Marshall, Alan G.; Heeren, Ron M. A.; Nikolaev, Eugene N.

2012-02-01

109

Spatial heterodyne Stokes vector imaging of the motional Stark-Zeeman multiplet.  

PubMed

We present a general Stokes interferometer/polarimeter suitable for polarimetric imaging the elliptically polarized motional Stark-Zeeman multiplet. We also introduce a fully phase-heterodyne spatial multiplex variant of the system that has been used for imaging of Balmer alpha emission from the heating neutral beam in the KSTAR super-conducting tokamak in Korea. The polarimeter performance is illustrated using various polarization test targets. PMID:23126853

Howard, John; Chung, Jinil

2012-10-01

110

Vector constraints on western U.S. deformation from space geodesy, neotectonics, and plate motions  

NASA Technical Reports Server (NTRS)

The rate-of-slip vector on the San Andreas fault in central California estimated from geodetic and Holocene geological data is inconsistent with the prediction of rigid plate models such as RM2. This well-known 'San Andreas discrepancy' is diagnostic of plate deformation distributed both east of the fault in the Basin and Range and west of the fault along the California continental margin. Constraints on the integrated deformation rates across these two regions consistent with: (1) the kinematical boundary conditions imposed by the rigid plate model; (2) neotectonic and paleoseismic estimates of deformation rates; (3) ground-based geodetic measurements; and (4) rates of change observed by very long baseline interferometry along seven baselines to western U.S. sites are constructed. The space-geodetic data on Basin and Range extension taken over a 4-year interval are compatible with geological observations averaged over the Holocene; the best estimate of its integrated deformation rate, provided by the joint inversion of both data types, is 9.7 + or - 2.1 mm/yr, N 56 deg W + or - 10 deg, too small and in the wrong direction to account entirely for the San Andreas discrepancy. The integral of this deformation, estimated by subtracting the Basin and Range contribution from the discrepancy vector, requires significant right-lateral shear parallel to the San Andreas (13 + or - 5 mm/yr) and some compression perpendicular to it (9 + or - 3 mm/yr).

Minster, J. Bernard; Jordan, Thomas H.

1987-01-01

111

THE M31 VELOCITY VECTOR. I. HUBBLE SPACE TELESCOPE PROPER-MOTION MEASUREMENTS  

SciTech Connect

We present the first proper-motion (PM) measurements for the galaxy M31. We obtained new V-band imaging data with the Hubble Space Telescope ACS/WFC and the WFC3/UVIS instruments of three fields: a spheroid field near the minor axis, an outer disk field along the major axis, and a field on the Giant Southern Stream. The data provide five to seven year time baselines with respect to pre-existing deep first-epoch observations of the same fields. We measure the positions of thousands of M31 stars and hundreds of compact background galaxies in each field. High accuracy and robustness is achieved by building and fitting a unique template for each individual object. The average PM for each field is obtained from the average motion of the M31 stars between the epochs with respect to the background galaxies. For the three fields, the observed PMs ({mu}{sub W}, {mu}{sub N}) are, in units of mas yr{sup -1}, (- 0.0458, -0.0376) {+-} (0.0165, 0.0154), (- 0.0533, -0.0104) {+-} (0.0246, 0.0244), and (- 0.0179, -0.0357) {+-} (0.0278, 0.0272), respectively. The ability to average over large numbers of objects and over the three fields yields a final displacement accuracy of a few thousandths of a pixel, corresponding to only 12 {mu}as yr{sup -1}. This is comparable to what has been achieved for other Local Group galaxies using Very Long Baseline Array observations of water masers. Potential systematic errors are controlled by an analysis strategy that corrects for detector charge transfer inefficiency, spatially and time-dependent geometric distortion, and point-spread function variations. The robustness of the PM measurements and uncertainties are supported by the fact that data from different instruments, taken at different times and with different telescope orientations, as well as measurements of different fields, all yield statistically consistent results. Papers II and III of this series explore the implications of the new measurements for our understanding of the history, future, and mass of the Local Group.

Sohn, Sangmo Tony; Anderson, Jay; Van der Marel, Roeland P., E-mail: tsohn@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2012-07-01

112

Motion.  

ERIC Educational Resources Information Center

This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

Brand, Judith, Ed.

2002-01-01

113

ULTRAVIOLET INDUCED MOTION OF A FLUORESCENT DUST CLOUD IN AN ARGON DIRECT CURRENT GLOW DISCHARGE PLASMA  

SciTech Connect

Dusty plasmas consist of electrons, ions, neutrals and nm-?m sized particles commonly referred to as dust. In man-made plasmas this dust may represent impurities in a tokamak or plasma etching processing. In astrophysical plasmas this dust forms structures such as planetary rings and comet tails. To study dusty plasma dynamics an experiment was designed in which a 3:1 silica (<5 ?m diameter) and fl uorescent dust mixture was added to an argon DC glow discharge plasma and exposed to UV radiation. This fl uorescent lighting technique offers an advantage over laser scattering (which only allows two-dimensional slices of the cloud to be observed) and is simpler than scanning mirror techniques or particle image velocimetry. Under typical parameters (P=150 mTorr, V anode= 100 V, Vcathode= -400 V, Itotal < 2mA) when the cloud is exposed to the UV light (100W, ? = 365 nm) the mixture fl uoresces, moves ~2mm towards the light source and begins rotating in a clockwise manner (as seen from the cathode). By calibrating a UV lamp and adjusting the relative intensity of the UV with a variable transformer it was found that both translational and rotational velocities are a function of UV intensity. Additionally, it was determined that bulk cloud rotation is not seen when the dust tray is not grounded while bulk translation is. This ongoing experiment represents a novel way to control contamination in man-made plasmas and a path to a better understanding of UV-bathed plasma systems in space..

Hvasta, M.G.; and Zwicker, A.

2008-01-01

114

Investigation of cloud/water vapor motion winds from geostationary satellite  

NASA Technical Reports Server (NTRS)

Work has been primarily focussed on three tasks: (1) comparison of wind fields produced at MSFC with the CO2 autowind/autoeditor system newly installed in NESDIS operations; (2) evaluation of techniques for improved tracer selection through use of cloud classification predictors; and (3) development of height assignment algorithm with water vapor channel radiances. The contract goal is to improve the CIMSS wind system by developing new techniques and assimilating better existing techniques. The work reported here was done in collaboration with the NESDIS scientists working on the operational winds software, so that NASA funded research can benefit NESDIS operational algorithms.

Nieman, Steve; Velden, Chris; Hayden, Kit; Menzel, Paul

1993-01-01

115

A Benchmark for Cloud Tracking Wind Measurements  

NASA Astrophysics Data System (ADS)

Cloud tracking has been the primary method of measuring wind speeds in planetary atmospheres through Earth- and space- based remote sensing. Latest developments of automated feature tracking software are able to harvest thousands of wind vectors out of a sequence of high-resolution images acquired with an appropriate temporal separation. However, unlike satellite-based cloud-tracking measurements of Earth, these planetary measurements cannot easily be validated against in-situ data, which makes the interpretation difficult when different cloud-tracking schemes do not agree on their results. To address the issue of data validation, we run multiple automated cloud-tracking software independently developed at multiple institutions on synthetic wind data generated using a General Circulation Model. Our simulations calculate the advection of tracer distributions to represent cloud motions as done by Sayanagi and Showman (2007, Icarus 187, p520-539). The motions of tracers are measured using cloud-tracking software to derive wind vector fields, which will be compared against the model "truth." We test the performance of cloud-tracking software for different wind scenarios. Our first test wind field contains a simple zonal jet. The second test scenario is a large vortex like Jupiter’s Great Red Spot. The third test case has waves propagating alongside a zonal jet. We compare the results returned from different cloud-tracking schemes and discuss what approaches work better at measuring winds. In addition to verifying the wind vector field measurements, we also address the accuracy and validity of eddy momentum flux measurements by tracking clouds. The difficulties of such measurements are discussed by Salyk et al. (2006, Icarus 185, p430-442), and we re-examine the issue using our synthetic wind data. From our experiments, we aim to establish a standard benchmark of cloud tracking measurements for planetary mission applications.

Sayanagi, K. M.; Mitchell, J.; Ingersoll, A. P.; Ewald, S. P.; Marcus, P. S.; de Pater, I.; Wong, M. H.; Choi, D. S.; Sussman, M.; Ogohara, K.; Imamura, T.; Kouyama, T.; Takagi, M.; Satoh, N.; Del Genio, A. D.; Barbara, J.; Sanchez-Lavega, A.; Hueso, R.; García-Melendo, E.; Simon-Miller, A. A.

2010-12-01

116

Low-power motion vector estimation using iterative search block-matching methods and a high-speed non-destructive CMOS image sensor  

Microsoft Academic Search

In this paper, motion vector (MV) estimation methods with high-speed intermediate pictures for low-power video compression are proposed. The intermediate pictures are obtained by a special type of CMOS image sensor. An adaptive iterative-search block matching is proposed to obtain precise MVs of video-rate pictures from high-speed intermediate pictures with the reduced computational complexity. The sensor captures high-speed intermediate pictures

Dwi Handoko; Shoji Kawahito; Yoshiaki Tadokoro; Akira Matsuzawa

2002-01-01

117

ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair)  

SciTech Connect

This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

Christopher Williams; Mike Jensen

2012-11-06

118

Nowcasting of cloud cover with MSG  

NASA Astrophysics Data System (ADS)

In this poster, an algorithm is shown to detect water and ice clouds seperately and forecast their developement for the next timesteps. It is based on Meteosat SEVIRI (Spinning Enhanced Visible and Infrared Imager) data from almost all channels with a timestep of 15 minutes. In order to derive cloud cover, optical depth and height of ice clouds the "Cirrus Optical properties derived from CALIOP and SEVIRI during day and night" (COCS) algorithm (Kox 2012) was used. For the determination of water clouds a cloud mask was developed. For a most accurate forecast the detected clouds are divided into two groups, convective and advective, and afterwards treated seperately. The forecast of advective clouds basically takes place with the pyramidal matcher ("optical flow" technique, Zinner et al. 2008) by determining a motion vector field from two consecutive images. The clouds are then classified as objects with similar properties (optical depth, temperature) and a forecast for each object separately is then performed. For the detection of convective clouds the tracking and nowcasting algorithm Cb-TRAM (CumulonimBus TRacking And Monitoring, Zinner et al. 2008) is used, which divides convection into three stages. The further development und thus the forecast of these clouds is dependent of the current stage. Appications to selected case studies will be shown.

Sirch, Tobias; Bugliaro, Luca

2014-05-01

119

Realistic modeling of ion cloud motion in a Fourier transform ion cyclotron resonance cell by use of a particle-in-cell approach.  

PubMed

Using a 'Particle-In-Cell' approach taken from plasma physics we have developed a new three-dimensional (3D) parallel computer code that today yields the highest possible accuracy of ion trajectory calculations in electromagnetic fields. This approach incorporates coulombic ion-ion and ion-image charge interactions into the calculation. The accuracy is achieved through the implementation of an improved algorithm (the so-called Boris algorithm) that mathematically eliminates cyclotron motion in a magnetic field from digital equations for ion motion dynamics. It facilitates the calculation of the cyclotron motion without numerical errors. At every time-step in the simulation the electric potential inside the cell is calculated by direct solution of Poisson's equation. Calculations are performed on a computational grid with up to 128 x 128 x 128 nodes using a fast Fourier transform algorithm. The ion populations in these simulations ranged from 1000 up to 1,000,000 ions. A maximum of 3,000,000 time-steps were employed in the ion trajectory calculations. This corresponds to an experimental detection time-scale of seconds. In addition to the ion trajectories integral time-domain signals and mass spectra were calculated. The phenomena observed include phase locking of particular m/z ions (high-resolution regime) inside larger ion clouds. A focus was placed on behavior of a cloud of ions of a single m/z value to understand the nature of Fourier transform ion cyclotron resonance (FTICR) resolution and mass accuracy in selected ion mode detection. The behavior of two and three ion clouds of different but close m/z was investigated as well. Peak coalescence effects were observed in both cases. Very complicated ion cloud dynamics in the case of three ion clouds was demonstrated. It was found that magnetic field does not influence phase locking for a cloud of ions of a single m/z. The ion cloud evolution time-scale is inversely proportional to magnetic field. The number of ions needed for peak coalescence depends quadratically on the magnetic field. PMID:17944004

Nikolaev, Eugene N; Heeren, Ron M A; Popov, Alexander M; Pozdneev, Alexander V; Chingin, Konstantin S

2007-01-01

120

Invariant conformal vectors in space-times admitting a group of G/sub 3/ of motions acting on spacelike orbits S/sub 2/  

SciTech Connect

The paper deals with four-dimensional space-times admitting locally a three-dimensional group of motions G/sub 3/ acting on two-dimensional spacelike orbits S/sub 2/. The local existence problem for conformal vectors invariant under G/sub 3/ is shown to be equivalent to the local existence problem for Killing vectors of a given two-dimensional pseudo-Riemannian metric g. This problem is explicitly solved in terms of the Gaussian curvature R of g and two of its scalar differential concomitants. The results are applied to the case of dust-filled space-times, where an exhaustive list of metrics has been obtained by using the algebraic computing language Sm-smcapsp-smcaps.-smcaps The metrics are either homogeneous, self-similar, or Friedmann models.

Bona, C.

1988-11-01

121

A Vector-Dyadic Development of the Equations of Motion for n-Coupled Flexible Bodies and Point Masses.  

National Technical Information Service (NTIS)

The equations of motion for a system of coupled flexible bodies, rigid bodies, point masses, and symmetric wheels were derived. The equations were cast into a partitioned matrix form in which certain partitions became nontrivial when the effects of flexib...

H. P. Frisch

1975-01-01

122

Developing a Standardized Testing Procedure for Cloud Tracking Wind Measurement Methods  

NASA Astrophysics Data System (ADS)

We present preliminary results of our effort to develop a standardized benchmark test for cloud tracking wind measurement methods. Various algorithms have been developed over the years to measure wind speeds in planetary atmospheres through Earth- and space- based remote sensing. However, unlike satellite-based cloud-tracking measurements of Earth, these planetary measurements cannot easily be validated against in-situ data, which makes the interpretation difficult when different cloud-tracking schemes do not agree on their results. To address the issue of data validation, we run multiple automated cloud-tracking algorithms independently developed at multiple institutions on synthetic wind data generated using a General Circulation Model. Our simulations calculate the advection of tracer distributions to represent cloud motions as done by Sayanagi and Showman (2007, Icarus 187, p520-539). The motions of tracers are measured using cloud-tracking software to derive wind vector fields, which will be compared against the model "truth." In our synthetic wind/cloud fields, the tempo-spatial scales of the winds and clouds are separately controlled so that the robustness of cloud tracking tools can be assessed against various conditions. Our setup enables measuring the performance of cloud-tracking software using two metrics. The first metric is the ratio between characteristic length scale of cloud morphology Lcloud and the size of smallest eddies successfully resolved by a cloud-tracking method LLeddy, ? = Lcloud/L_{Leddy}. The second performance metric is the ratio between the temporal interval between image acquisitions Timaging and the characteristic lifetime of clouds Tcloud, ? = Timaging/T_cloud. These metrics are designed to compare the abilities of tracking algorithms to resolve cloud motions against the absolute theoretical limit; note that both metrics have the maximum value of 1.0 as cloud tracking methods cannot resolve features that change in less than the temporal and spatial scales of the clouds. Our study is supported by a grant from the NSF Planetary Astronomy program.

Sayanagi, K. M.; Barbara, J. M.; Bourque, B.; Choi, D. S.; De Pater, I.; Del Genio, A. D.; Ewald, S.; Garcia-Melendo, E.; Heavens, N. G.; Hueso, R.; Imamura, T.; Ingersoll, A. P.; Kouyama, T.; Liu, T.; Marcus, P. S.; Mitchell, J.; Ogohara, K.; Read, P. L.; Sanchez-Lavega, A.; Simon-Miller, A. A.; Sussman, M.; Takagi, M.; Wong, M. H.; Young, R. M.

2012-12-01

123

MISR Level 2 TOA/Cloud Stereo parameters (MIL2TCST_V1)  

NASA Technical Reports Server (NTRS)

The MISR Top-of-Atmosphere (TOA)/Cloud Stereo geophysical parameters include stereoscopically-derived cloud motion vectors (winds), cloud-top heights, and an accompanying cloud mask. The Stereo product geophysical parameters include a stereoscopically-derived cloud mask and cloud height on a 1.1 km grid. It also includes cloud motion vectors on a 70.4 km grid. The three types of stereo heights are: the BestWind heights are only calculated for those regions where the associated wind vectors passed the quality tests. Therefore, they have sparse coverage but since the wind correction is included, these contain our 'best guess' as to what the true heights are. The WithoutWind heights are calculated assuming a constant wind vector of zero. They have almost complete coverage and therefore form a nice 'pretty picture' of the relative cloud heights over small areas. The RawWind heights are a diagnostic product as they are calculated using all available wind vectors (even the bad ones). It is therefore recommended that one only use the Best and Without wind products. It is important to remember that the stereo matchers pick up the layer of maximum contrast, which is not necessarily the same as the highest cloud so all the stereo heights are keyed to this level of maximum contrast. Therefore, higher and thinner cirrus layers may not be detected by any of the height fields. [Location=GLOBAL] [Temporal_Coverage: Start_Date=2000-02-24; Stop_Date=] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1.1 km; Longitude_Resolution=1.1 km; Horizontal_Resolution_Range=1 km - < 10 km or approximately .01 degree - < .09 degree; Temporal_Resolution=about 15 orbits/day; Temporal_Resolution_Range=Daily - < Weekly].

Diner, David J. (Principal Investigator)

124

MISR Level 2 TOA/Cloud Stereo parameters (MIL2TCST_V2)  

NASA Technical Reports Server (NTRS)

The MISR Top-of-Atmosphere (TOA)/Cloud Stereo geophysical parameters include stereoscopically-derived cloud motion vectors (winds), cloud-top heights, and an accompanying cloud mask. The Stereo product geophysical parameters include a stereoscopically-derived cloud mask and cloud height on a 1.1 km grid. It also includes cloud motion vectors on a 70.4 km grid. The three types of stereo heights are: the BestWind heights are only calculated for those regions where the associated wind vectors passed the quality tests. Therefore, they have sparse coverage but since the wind correction is included, these contain our 'best guess' as to what the true heights are. The WithoutWind heights are calculated assuming a constant wind vector of zero. They have almost complete coverage and therefore form a nice 'pretty picture' of the relative cloud heights over small areas. The RawWind heights are a diagnostic product as they are calculated using all available wind vectors (even the bad ones). It is therefore recommended that one only use the Best and Without wind products. It is important to remember that the stereo matchers pick up the layer of maximum contrast, which is not necessarily the same as the highest cloud so all the stereo heights are keyed to this level of maximum contrast. Therefore, higher and thinner cirrus layers may not be detected by any of the height fields. [Temporal_Coverage: Start_Date=2000-02-24; Stop_Date=] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1.1 km; Longitude_Resolution=1.1 km; Temporal_Resolution=about 15 orbits/day].

Diner, David J. (Principal Investigator)

125

Local boundary layer, vertical motions measured with 1290 MHz profiler and Ceilometer cloud heights over a high altitude location in the central Himalaya  

NASA Astrophysics Data System (ADS)

Manora peak is a high altitude station (about 2 km, amsl) in the central Himalays, well above planetary boundary layer, hence the observations of clouds and study of the local boundary over the station is essential to understand the dynamics caused by mountains and meteorology of the region. Vaisala Radar Wind Profiler (RWP) to measure the winds and vertical motions in the lowest 4 km of the troposphere, and to find the cloud heights a Vaisala Ceilometer (VCEIL) were installed and operated at the ARM mobile facility site (AMF1) ARIES, Nainital (29.50N, 79.50E, ~2 km amsl), under the Indo-US collaborative field programme termed as Regional Aerosols Warming Experiment-Ganges Valley Aerosol Experiment (RAWEX-GVAX). Observations with RWP commenced since November 2011, whereas Ceilometer had been operational since June 2011 and collected data during monsoon and the campaign ended in March 2012. RWP is an active remote sensing device that operates unattended and provides continuous, real-time observations with excellent spatial and temporal (60 m) resolution. RWP observations do not show significant variations in the local boundary layer within the season e.g. winter months and spring, but 200m about 500m variation from winter to spring. Over the entire period of observation, anabatic winds are found usually in the forenoon and sinking motions in the evening hours mostly within 1 ms-1. VCEIL is a self-contained, ground-based, active remote-sensing device designed to measure cloud-base height to a maximum of 7.6 km and potential backscatter signals by aerosols. In case of the Ceilometer, cloud height varies from day to day, but the observed values during monsoon months of 2011, range between 400 m to 3000 m, above ground level. In addition, the observations made with micro pulse Lidar, Doppler Lidar and the co-located facilities for meteorological parameters, will be utilized to understand the lower atmospheric dynamics over the mountains. Details will be discussed during the presentation.

Singh, N.; Naja, M. K.; Dumka, U. C.; Phanikumar, D.; Pant, P.; Sagar, R.; Satheesh, S.; Krishnamoorthy, K.; Kotamarthi, V. R.

2012-12-01

126

Low Cloud Type over the Ocean from Surface Observations. Part III: Relationship to Vertical Motion and the Regional Surface Synoptic Environment.  

NASA Astrophysics Data System (ADS)

Composite large-scale dynamical fields contemporaneous with low cloud types observed at midlatitude Ocean Weather Station (OWS) C and eastern subtropical OWS N are used to establish representative relationships between low cloud type and the synoptic environment. The composites are constructed by averaging meteorological observations of surface wind and sea level pressure from volunteering observing ships (VOS) and analyses of sea level pressure, 1000-mb wind, and 700-mb pressure vertical velocity from the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalysis project on those dates and times of day when a particular low cloud type was reported at the OWS.VOS and NCEP results for OWS C during summer show that bad-weather stratus occurs with strong convergence and ascent slightly ahead of a surface low center and trough. Cumulus-under-stratocumulus and moderate and large cumulus occur with divergence and subsidence in the cold sector of an extratropical cyclone. Both sky-obscuring fog and no-low-cloud typically occur with southwesterly flow from regions of warmer sea surface temperature and differ primarily according to slight surface convergence and stronger warm advection in the case of sky-obscuring fog or surface divergence and weaker warm advection in the case of no-low-cloud. Fair-weather stratus and ordinary stratocumulus are associated with a mixture of meteorological conditions, but differ with respect to vertical motion in the environment. Fair-weather stratus occurs most commonly in the presence of slight convergence and ascent, while stratocumulus often occurs in the presence of divergence and subsidence.Surface divergence and estimated subsidence at the top of the boundary layer are calculated from VOS observations. At both OWS C and OWS N during summer and winter these values are large for ordinary stratocumulus, less for cumulus-under-stratocumulus, and least (and sometimes slightly negative) for moderate and large cumulus. Subsidence interpolated from NCEP analyses to the top of the boundary layer does not exhibit such variation, but the discrepancy may be due to deficiencies in the analysis procedure or the boundary layer parameterization of the NCEP model. The VOS results suggest that decreasing divergence and subsidence in addition to increasing sea surface temperature may promote the transition from stratocumulus to trade cumulus observed over low-latitude oceans.

Norris, Joel R.; Klein, Stephen A.

2000-01-01

127

Probability Based Search Motion Estimation Algorithm  

Microsoft Academic Search

We propose probabilistic method to determine motion vector (MV) for block matching algorithm (BMA). Proposed method allow us to exploit random distribution of motion vector in successive video frames for selection of initial search points for first iteration and refinement stage used in further iteration tracks motion vector in continuously changing video sequence. In our proposed algorithm due to adaptive

Deepak J. Jayaswal; M. A. Zaveri

2009-01-01

128

The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. III - Air-motions and precipitation growth in a warm-frontal rainband  

NASA Astrophysics Data System (ADS)

Doppler radar data and airborne cloud microphysical measurements obtained in the CYCLES Project indicate that a warm-frontal rainband in an extratropical cyclone was characterized by a precipitation process in which clouds at low levels were enhanced by a mesoscale updraft. Ice particles, apparently formed in shallow convective cells aloft, then drifted downward, undergoing aggregation just above the melting layer. This study demonstrates the crucial role of the low-level mesoscale updraft in condensing a sufficient amount of cloud water for particles to accrete as they fell through the lower portion of the frontal cloud.

Houze, R. A., Jr.; Rutledge, S. A.; Matejka, T. J.; Hobbs, P. V.

1981-03-01

129

The Mesoscale and Microscale Structure and Organization of Clouds and Precipitation in Midlatitude Cyclones. III: Air Motions and Precipitation Growth in a Warm-Frontal Rainband.  

NASA Astrophysics Data System (ADS)

Doppler radar data and airborne cloud microphysical measurements obtained in the CYCLES PROJECT indicate that a warm-frontal rainband in an extratropical cyclone was characterized by a precipitation process in which clouds at low levels were enhanced by a mesoscale updraft. Ice particles, apparently formed in shallow convective cells aloft and then drifted downward, undergoing aggregation just above the melting layer. This study demonstrates the crucial role of the low-level mesoscale updraft in condensing a sufficient amount of cloud water for particles to accrete as they fell through the lower portion of the frontal cloud.

Houze, Robert A., Jr.; Rutledge, Steven A.; Matejka, Thomas J.; Hobbs, Peter V.

1981-03-01

130

Local Cloud structure from HST-GHRS.  

NASA Astrophysics Data System (ADS)

Echelle spectra at high resolution (?/{DELTA}?= 90,000) of the nearby stars ? Aql (Altaie r), ? Lyr (Vega), ? Cen and ? Cas, have been obtained with the Goddard High-Resolution Spectrograph (GHRS) on board the Hubble Space Telescope (HST), during the cycles 1 and 3. In all but one spectra, interstellar Fe II and Mg II absorption lines are detected at the exact Doppler shifts expected for the Local Interstellar Cloud (LIC) velocity vector, providing new confirmations of this vector. These new results are combined with observations of ? CMa (Sirius), ? Aur (Capella), ? Pic, G191-B2B, ? PsA (Fomalhaut) and ? Leo, also obtained with the GHRS. For these targets too, absorption lines are detected at the expected LIC Doppler shift. ? Cen is exceptional, since its spectrum shows gas about 3km/s faster than the 26km/s velocity compatible with all other stars, confirming that towards this direction a faster second cloud, or a faster extension of the LIC, is present in the immediate vicinity of the Sun. From the measured LIC column-densities a first rough schematic view of its contours in the galactic plane can be drawn. The distance to the cloud surface is estimated depending on the actual neutral H density. At least 7 (resp. 5) cloudlets, or masses of gas with different individual motions, do exist within a sphere of 12 (resp. 7) pc radius (LIC included). We also provide upper limits on Vega and Altaie r circumstellar Fe II.

Lallement, R.; Ferlet, R.; Lagrange, A. M.; Lemoine, M.; Vidal-Madjar, A.

1995-12-01

131

Multiple description coding of motion fields for robust video transmission  

Microsoft Academic Search

In many video-coding standards, the motion vector field is one of the most important data in the compressed bitstream, and its loss can lead to severe degradation in the decoded picture quality. We propose the multiple description motion coding (MDMC) algorithm to enhance the robustness of the motion vector field against transmission errors. In MDMC, the motion vector field is

Chang-su Kim; Sang-Uk Lee

2001-01-01

132

A Sharper View of Venus:Strategies For Precise Cloud Tracking of Venus' Lower Cloud Deck  

NASA Astrophysics Data System (ADS)

We have observed the nightside of Venus at 2.3 microns using both IRTF on Mauna Kea and APO in New Mexico during the past two inferior conjuctions. Using IRTF we observed over a ten day span for 3-hours each day, which is sufficient to determine the major cloud motions. More recently by using both APO and IRTF we achieved a 5-hour temporal baseline each day over six days of observation. We see the lower cloud deck of Venus (48-52 km) backlit by 2.3 micron thermal radiation emanating from the surface and the lower atmosphere. These observations have allowed us to derive cloud-level wind speeds, and identify transient features in the observed Venusian wind field. We have adapted feature-tracking algorithms from several terrestrial remote sensing applications (e.g., Wu Inter. J. Remote Sensing, 1997, 2003; Bhat IEEE Trans. on PAMI, 20, 1998; Evans, IEEE Proc. of IGRSS, 1999) in order to track cloud movement. While this is still a work in progress, we show wind vector fields based on these algorithms and discuss their potential advantages and shortfalls. Our observations typically consist of many (a few thousand) short exposures of Venus during each twilight opportunity. These sequences lend themselves to image restoration processing by iterative blind deconvolution. We present restorations implemented using "IDAC" (Jefferies and Christou, ApJ, 415, 1993), a code that is distributed through the Center for Adaptive Optics at UC Santa Cruz. The use of IDAC has significantly increased the resolution of our ground based observations of Venus. This increases the accuracy of our wind speed measurements to the point were we can look for meridional motion. We will be presenting our most recent results and vector fields. This work supported by NASA's Infrared Telescope Facility and by the NASA Planetary Astronomy Program.

Tavenner, Tanya; Young, E. F.; Murphy, J.; Coyote, S.; Bullock, M.; Rafkin, S.

2006-09-01

133

An Example of Vector Algebra in Navigation.  

ERIC Educational Resources Information Center

A technique is illustrated for solving relative motion problems using a maneuvering board and vector algebra. The technique can be used to visually illustrate properties of vector algebra in a non-theoretical context. (MP)

Kjeseth, Steve

1979-01-01

134

Planetary and Satellite Motion  

NSDL National Science Digital Library

This Physics Classroom page explains how to conceptualize the motion of a satellite in orbit as the motion of a projectile. Several diagrams illustrate the ideas in the text; one shows the force and acceleration vectors on a satellite at different places in its orbit.

2012-11-29

135

Physclips: Circular Motion  

NSDL National Science Digital Library

This web page provides a multimedia introduction to circular motion. It includes topics such as acceleration, velocity, vectors, the Earth's rotation, and nonuniform circular motion. Short video clips and diagrams are integrated with text to promote understanding of important concepts. This tutorial is part of the PhysClip collection of web-based resources on introductory mechanics, electricity, and magnetism.

Wolfe, Joe

2009-10-14

136

Hierarchical variable block size motion estimation technique for motion sequence coding  

NASA Astrophysics Data System (ADS)

Motion-compensated coding, which exploits the temporal redundancies in the moving image, is one of the most popular techniques currently used. Recently, a variable block size (VBS) motion estimation technique has been proposed to improve the performance of the motion- compensated transform coding (MCTC). This technique allows larger blocks to be used when smaller blocks provide little gain, saving the bit rates especially for areas containing more complex motion. However, there have been few efforts to investigate an efficient VBS motion structure for reducing the motion vector coding rates further. Hence, a new VBS motion estimation technique based on a hierarchical structure is proposed that improves the motion vector encoding efficiency and reduces the number of motion vectors to be transmitted as well. Specifically, the gain/cost motion estimation technique with the selective motion prediction is utilized for the topmost level motion vector search, exploiting the redundancies among the neighboring motion vectors. Also, a restricted search with respect to the topmost level motion vector enables more flexible and efficient motion vector encoding for the remaining lower level blocks. Intensive simulations on several moving image sequences show that the MTC employing the VBS motion estimation provides a performance improvement of 0.7 to 1.0 dB, in terms of peak SNR, compared with the fixed block size motion estimation.

Kim, Jong-Won; Lee, Sang U.

1994-08-01

137

An eigenspace-based approach for human fall detection using Integrated Time Motion Image and multi-class Support Vector Machine  

Microsoft Academic Search

Falls are a major health hazard for the elderly and a serious obstacle for independent living. Since falling causes dramatic physical-psychological consequences, development of intelligent video surveillance systems is so important due to providing safe environments. To this end, this paper proposes a novel approach for human fall detection based on combination of integrated time motion images and eigenspace technique.

Homa Foroughi; Hadi Sadoghi Yazdi; Hamidreza Pourreza; Malihe Javidi

2008-01-01

138

Physclips: Vectors  

NSDL National Science Digital Library

This website provides an introduction to vectors. It includes topics such as magnitude and direction, components, unit vectors, vectors in three dimensions, vector addition and subtraction, and scalar and vector products. Animations, still images, graphs, and diagrams are used to illustrate important concepts. This tutorial is part of the PhysClips collection of web-based resources on introductory mechanics, electricity, and magnetism.

Wolfe, Joe

2009-01-20

139

Robust motion-compensated video upconversion  

Microsoft Academic Search

The quality of field-rate conversion improves significantly with motion-compensation techniques. It becomes possible to interpolate new fields at their correct temporal position. This results in smooth motion portrayal without loss of temporal resolution. However, motion vectors are not always valid for every pixel or object in an image. Therefore, visible artifacts occur wherever such wrong vectors are used on the

Olukayode Anthony Ojo; Gerard de Haan

1997-01-01

140

Vector reconstruction from firing rates  

Microsoft Academic Search

In a number of systems including wind detection in the cricket, visual motion perception and coding of arm movement direction in the monkey and place cell response to position in the rat hippocampus, firing rates in a population of tuned neurons are correlated with a vector quantity. We examine and compare several methods that allow the coded vector to be

Emilio Salinas; L. F. Abbott

1994-01-01

141

Cold, Clouds, and Snowflakes  

NSDL National Science Digital Library

Snow and ice are both precipitation, that is, the processes that remove water from clouds. Clouds, regions of the atmosphere with high relative humidity, are made of droplets of water and perhaps bits of ice. Even though water is much denser than air, these droplets and ice crystals are small enough to be suspended by random upward air motion. When these droplets or crystals join together, gravity overcomes the suspending force and we have precipitation. In this lesson, students will investigate NASA satellite data to determine geographical areas where wintry precipitation may have occurred based on cloud top temperature. They will explore the relationship between the amount of water vapor and the temperature of clouds, as well as snowflake shapes and cloud temperature.

142

Cloud track wind using synergism of backscatter lidar and sky digital picture  

NASA Astrophysics Data System (ADS)

Cloud altitude measurements by a 532nm backscatter Lidar and time lapsed digital photography are combined to monitor the cloud velocity profile. The cloud images are recorded in time steps of two seconds by a Nikon D100 digital camera through a 63° solid angle while the Lidar was measuring the cloud altitude. The images are recorded in 8 bits gray scale JPG format in an array of 2240×1488 pixels. To measure the angular displacement of different parts of the cloud, each image is meshed into an array of 44×29 cells, each cell contains 50×50 pixels. The grayscale density cross correlations between similar cells of successive images are computed using a MATLAB code developed by us for this application. The output products are the direction and the amount of displacement of each cell, in pixels. combining the results on cloud displacement with Lidar measurements enable to calculate the velocity vector in each cell. The resolution in velocity is about 1 ms-1 and 2° in direction. The calculation technique also is tested by simulating the cloud motion by moving the image pixels with a computer generated Gaussian velocity distribution.

Khalesifard, Hamid R.; Abdi, Farhad; Flamant, Pierre H.

2005-10-01

143

Cloud Interactions  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 1 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

This image was acquired during mid-spring near the North Pole. The linear water-ice clouds are now regional in extent and often interact with neighboring cloud system, as seen in this image. The bottom of the image shows how the interaction can destroy the linear nature. While the surface is still visible through most of the clouds, there is evidence that dust is also starting to enter the atmosphere.

Image information: VIS instrument. Latitude 68.4, Longitude 258.8 East (101.2 West). 38 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2004-01-01

144

A vector-dyadic development of the equations of motion for N-coupled flexible bodies and point masses. [spacecraft trajectories  

NASA Technical Reports Server (NTRS)

The equations of motion for a system of coupled flexible bodies, rigid bodies, point masses, and symmetric wheels were derived. The equations were cast into a partitioned matrix form in which certain partitions became nontrivial when the effects of flexibility were treated. The equations are shown to contract to the coupled rigid body equations or expand to the coupled flexible body equations all within the same basic framework. Furthermore, the coefficient matrix always has the computationally desirable property of symmetry. Making use of the derived equations, a comparison was made between the equations which described a flexible body model and those which described a rigid body model of the same elastic appendage attached to an arbitrary coupled body system. From the comparison, equivalence relations were developed which defined how the two modeling approaches described identical dynamic effects.

Frisch, H. P.

1975-01-01

145

Cooperative Phenomena in the Perception of Motion Direction,  

National Technical Information Service (NTIS)

A percept of global coherent motion can result from the combination of many different localized motion vectors. We report evidence of hysteresis in the perception of this global motion, obtained with random-dot cinematograms. The hysteresis characteristic...

D. Williams G. Phillips

1987-01-01

146

Project Physics Reader 1, Concepts of Motion.  

ERIC Educational Resources Information Center

As a supplement to Project Physics Unit 1, 21 articles are presented in this reader. Concepts of motion are discussed under headings: motion, motion in words, representation of movement, introducing vectors, Galileo's discussion of projectile motion, Newton's laws of dynamics, the dynamics of a golf club, report on Tait's lecture on force, and bad…

Harvard Univ., Cambridge, MA. Harvard Project Physics.

147

A Comparison of Several Techniques to Assign Heights to Cloud Tracers.  

NASA Astrophysics Data System (ADS)

Satellite-derived cloud-motion vector (CMV) production has been troubled by inaccurate height assignment of cloud tracers, especially in thin semitransparent clouds. This paper presents the results of an intercomparison of current operational height assignment techniques. Currently, heights are assigned by one of three techniques when the appropriate spectral radiance measurements are available. The infrared window (IRW) technique compares measured brightness temperatures to forecast temperature profiles and thus infers opaque cloud levels. In semitransparent or small subpixel clouds, the carbon dioxide (CO2) technique uses the ratio of radiances from different layers of the atmosphere to infer the correct cloud height. In the water vapor (H2O) technique, radiances influenced by upper-tropospheric moisture and IRW radiances are measured for several pixels viewing different cloud amounts, and their linear relationship is used to extrapolate the correct cloud height. The results presented in this paper suggest that the H2O technique is a viable alternative to the CO2 technique for inferring the heights of semitransparent cloud elements. This is important since future National Environmental Satellite, Data, and Information Service (NESDIS) operations will have to rely on H20-derived cloud-height assignments in the wind field determinations with the next operational geostationary satellite. On a given day, the heights from the two approaches compare to within 60 110 hPa rms; drier atmospheric conditions tend to reduce the effectiveness of the H2O technique. By inference one can conclude that the present height algorithms used operationally at NESDIS (with the C02 technique) and at the European Satellite Operations Center (ESOC) (with their version of the H20 technique) are providing similar results. Sample wind fields produced with the ESOC and NESDIS algorithms using Meteosat-4 data show good agreement.

Nieman, Steven J.; Schmetz, Johannes; Menzel, W. Paul

1993-09-01

148

Cloud Spirals and Outflow in Tropical Storm Katrina  

NASA Technical Reports Server (NTRS)

On Tuesday, August 30, 2005, NASA's Multi-angle Imaging SpectroRadiometer retrieved cloud-top heights and cloud-tracked wind velocities for Tropical Storm Katrina, as the center of the storm was situated over the Tennessee valley. At this time Katrina was weakening and no longer classified as a hurricane, and would soon become an extratropical depression. Measurements such as these can help atmospheric scientists compare results of computer-generated hurricane simulations with observed conditions, ultimately allowing them to better represent and understand physical processes occurring in hurricanes.

Because air currents are influenced by the Coriolis force (caused by the rotation of the Earth), Northern Hemisphere hurricanes are characterized by an inward counterclockwise (cyclonic) rotation towards the center. It is less widely known that, at high altitudes, outward-spreading bands of cloud rotate in a clockwise (anticyclonic) direction. The image on the left shows the retrieved cloud-tracked winds as red arrows superimposed across the natural color view from MISR's nadir (vertical-viewing) camera. Both the counter-clockwise motion for the lower-level storm clouds and the clockwise motion for the upper clouds are apparent in these images. The speeds for the clockwise upper level winds have typical values between 40 and 45 m/s (144-162 km/hr). The low level counterclockwise winds have typical values between 7 and 24 m/s (25-86 km/hr), weakening with distance from the storm center. The image on the right displays the cloud-top height retrievals. Areas where cloud heights could not be retrieved are shown in dark gray. Both the wind velocity vectors and the cloud-top height field were produced by automated computer recognition of displacements in spatial features within successive MISR images acquired at different view angles and at slightly different times.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82o north and 82o south latitude every nine days. This image covers an area of about 380 kilometers by 1970 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbit 30324 and utilize data from blocks 55-68 within World Reference System-2 path 22.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology.

2005-01-01

149

Cloud Fun  

NSDL National Science Digital Library

Learners complete a series of hands-on and investigative activities to explore cumulus clouds. Learners observe cumulus clouds outside, read a book about how cumulus clouds differ from other clouds, and create a list of words that describe cumulus clouds. Then, learners create their own cumulus cloud out of white paper and complete the Cloud Fun Student Activity sheet that includes a description of the cloud and what the weather was like on the day the cloud was observed. Learners will use their five senses to describe their clouds. Clouds can be displayed in the classroom or assembled into a class book. This lesson guide includes brief background information about cumulus clouds, adaptations for younger and older learners, and extension ideas.

Program, The G.

2006-01-01

150

Vector Voyage!  

NSDL National Science Digital Library

In this activity, students will use vector analysis to understand the concept of dead reckoning. Students will use vectors to plot their course based on a time and speed. They will then correct the positions with vectors representing winds and currents.

Integrated Teaching And Learning Program

151

Vector Voyage!  

NSDL National Science Digital Library

In this activity, students will use vector analysis to understand the concept of dead reckoning. Students will use vectors to plot their course based on a time and speed. They will then correct the positions with vectors representing winds and currents.

White, Jeff; Lippis, Matt; Axelrad, Penny; Yowell, Janet; Zarske, Malinda S.

2004-01-01

152

Hierarchical variable block size motion estimation technique for motion sequence coding  

NASA Astrophysics Data System (ADS)

Recently, a variable block size (VBS) motion estimation technique has been employed to improve the performance of the motion compensated transform coding (MCTC). This technique allows larger blocks to be used when smaller blocks provide little gain, saving the bit rates especially for areas containing more complex motion. However, there has been little effort in investigating an efficient VBS motion structure for reducing the motion vector coding rates further. Hence, in this paper, a new VBS motion estimation technique based on a hierarchical structure is proposed, which improves the motion vector encoding efficiency and reduces the number of motion vectors to be transmitted as well. Intensive computer simulations on several moving image sequences show that the MCTC employing the VBS motion estimation provides a performance improvement of 0.7 to approximately 1.0 dB, in terms of PSNR, compared to the fixed block size motion estimation.

Kim, Jong-Won; Lee, Sang U.

1993-10-01

153

Interstellar molecular clouds  

NASA Astrophysics Data System (ADS)

The physical properties of the molecular phase of the interstellar medium are studied with regard to star formation and the structure of the Galaxy. Most observations of molecular clouds are made with single-dish, high-surface precision radio telescopes, with the best resolution attainable at 0.2 to 1 arcmin; the smallest structures that can be resolved are of order 10 to the 17th cm in diameter. It is now believed that: (1) most of the mass of the Galaxy is in the form of giant molecular clouds; (2) the largest clouds and those responsible for most massive star formation are concentrated in spiral arms; (3) the molecular clouds are the sites of perpetual star formation, and are significant in the chemical evolution of the Galaxy; (4) giant molecular clouds determine the evolution of the kinematic properties of galactic disk stars; (5) the total gas content is diminishing with time; and (6) most clouds have supersonic internal motions and do not form stars on a free-fall time scale. It is concluded that though progress has been made, more advanced instruments are needed to inspect the processes operating within stellar nurseries and to study the distribution of the molecular clouds in more distant galaxies. Instruments presently under construction which are designed to meet these ends are presented.

Bally, J.

1986-04-01

154

Graph Matching Motion Model  

NSDL National Science Digital Library

The Graph Matching Motion Model shows the graph of position as a function of time, and the motion diagram, for a particular object that experiences one-dimensional motion with constant acceleration. Using the sliders, try to match the motion of the red object to that of the blue object - this should also get the two position versus time graphs to match. Then, predict what the velocity and acceleration graphs look like, by sliding the end points of the red lines up or down to give correct straight-line graphs. The Graph Matching Motion model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_graph_matching.jar file will run the program if Java is installed.

Duffy, Andrew

2010-05-02

155

Cloud Protocols  

NSDL National Science Digital Library

The purpose of this activity is to observe the type and cover of clouds including contrails. Students observe which of ten types of clouds and how many of three types of contrails are visible and how much of the sky is covered by clouds (other than contrails) and how much is covered by contrails. Intended outcomes are that students learn how to make estimates from observations and how to categorize specific clouds following general descriptions for the categories. They will learn the meteorological concepts of cloud heights, types, and cloud cover and learn the ten basic cloud types. Supporting background materials for both student and teacher are included.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

156

PRESENT-DAY PLATE MOTIONS  

Microsoft Academic Search

A data set comprising 110 spread- ing rates, 78 transform fault azimuths, and 142 earthquake slip vectors has been inverted to yield a new instantaneous plate motion model, designated Relative Motion 2 (RM2). The model represents a considerable improvement over our previous estimate, RM1 (Minster et al., 1974). The mean averaging interval for the spreading rate data has been reduced

J. Bernard Minster; Thomas H. Jordan

1978-01-01

157

Present-Day Plate Motions.  

National Technical Information Service (NTIS)

A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to le...

J. B. Minster T. H. Jordan

1977-01-01

158

Motion-Compensated 3-D Subband Coding with Multiresolution Representation of Motion Parameters  

Microsoft Academic Search

This paper concentrates on the aspects of motion estimation and representation in the framework of motion-compensated 3-D subband coding. The motion vector field (MVF) is estimated hierarchically, based on a description obtained from a decimated field of support points. Displ acements in between these points are interpolated. The motion parameters are encoded by use of a 3-D Laplacian pyramid structure,

Jens-rainer Ohm

1994-01-01

159

Analysis and forecast experiments incorporating satellite soundings and cloud and water vapor drift wind information  

NASA Technical Reports Server (NTRS)

A system for assimilating conventional meteorological data and satellite-derived data in order to produce four-dimensional gridded data sets of the primary atmospheric variables used for updating limited area forecast models is described. The basic principles of a data assimilation scheme as proposed by Lorenc (1984) are discussed. The design of the system and its incremental assimilation cycles are schematically presented. The assimilation system was tested using radiosonde, buoy, VAS temperature, dew point, gradient wind data, cloud drift, and water vapor motion data. The rms vector errors for the data are analyzed.

Goodman, Brian M.; Diak, George R.; Mills, Graham A.

1986-01-01

160

The Influence of Shear Motion on Evolution of Giant Molecular Associations  

NASA Astrophysics Data System (ADS)

The evolution of Giant Molecular Clouds (GMCs) and Giant Molecular Associations (GMAs) is one of the keys to understand massive star formation in a galaxy and hence evolution of the galaxy. It has been considered that GMCs and GMAs are formed in spiral arms. Recently, however, GMCs are found not only in the spiral arms but also in the inter-arms. It is suggested that the GMCs in the inter-arms might be formed by the shear motion. However, the relation between molecular clouds and the kinetic shear motion in the clouds is still speculation, because the kinetic shear has not been directly measured in a galaxy. We have investigated the dynamics of the molecular gas and the evolution of GMAs in the spiral galaxy M51 with the NRO 45-m telescope. The velocity components of the molecular gas perpendicular and parallel to the spiral arms were derived at each spiral phase from the distribution of the line-of-sight velocity of the CO gas. The shear motion in the galactic disk was determined from the velocity vectors at each spiral phase. It was revealed that the distributions of the shear strength and of GMAs are anti-correlated. In addition, GMAs can grow up just in regions where the gravitational critical density is larger than the critical shear density. This result suggests that the evolution of GMAs is heavily affected by the shear.

Miyamoto, Y.; Nakai, N.; Kuno, N.

2014-03-01

161

Optical Structure and Proper-Motion Age of the Oxygen-rich Supernova Remnant 1E 0102-7219 in the Small Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We present new optical emission-line images of the young SNR 1E 0102-7219 in the SMC obtained with the ACS on HST. This object is a member of the oxygen-rich class of SNRs showing strong oxygen, neon, and other metal-line emissions in its optical and X-ray spectra, and an absence of hydrogen and helium. The progenitor of 1E 0102-7219 may have been a Wolf-Rayet star that underwent considerable mass loss prior to exploding as a Type Ib/c or IIL/b supernova. The ejecta in this SNR are generally fast-moving (V>1000 km s-1) and emit as they are compressed and heated in the reverse shock. In 2003 we obtained optical [O III], H?, and continuum images with the ACS Wide Field Camera. The [O III] image through the F475W filter captures the full velocity range of the ejecta and shows considerable high-velocity emission projected in the middle of the SNR that was Doppler-shifted out of the narrow F502N bandpass of a previous WFPC2 image from 1995. Using these two epochs separated by ~8.5 yr, we measure the transverse expansion of the ejecta around the outer rim in this SNR for the first time at visible wavelengths. From proper-motion measurements of 12 ejecta filaments, we estimate a mean expansion velocity for the bright ejecta of ~2000 km s-1 and an inferred kinematic age for the SNR of ~2050+/-600 yr. The age we derive from HST data is about twice that inferred by Hughes et al. from X-ray data, although our 1 ? error bars overlap. Our proper-motion age is consistent with an independent optical kinematic age derived by Eriksen et al. in 2003 using spatially resolved [O III] radial-velocity data. We derive an expansion center that lies very close to conspicuous X-ray and radio hot spots, which could indicate the presence of a compact remnant (neutron star or black hole). Based on observations with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555.

Finkelstein, Steven L.; Morse, Jon A.; Green, James C.; Linsky, Jeffrey L.; Shull, J. Michael; Snow, Theodore P.; Stocke, John T.; Brownsberger, Kenneth R.; Ebbets, Dennis C.; Wilkinson, Erik; Heap, Sara R.; Leitherer, Claus; Savage, Blair D.; Siegmund, Oswald H.; Stern, Alan

2006-04-01

162

Cloud Formation, Sea-Air-Land Interaction, Mozambique, Africa  

NASA Technical Reports Server (NTRS)

This rare depiction of the physical interactions of air land and sea in cloud formation was seen over Mozambique (12.0S, 40.5E). Moist low air, heated as it moves over land, rises and forms clouds. Even the coastal islands have enough heat to initiate the process. Once begun, the circulation is dynamic and the descending motion suppresses cloud formation on either side of the cloud stream. As clouds move inland, they rise to follow the land upslope.

1991-01-01

163

Position, Velocity, and Acceleration in Uniform Circular Motion  

NSDL National Science Digital Library

This applet displays the position, velocity, and acceleration vectors for an object moving in uniform circular motion. The vectors are shown on different graphs. The graphs can be set to display constant motion or they can be paused and moved through the motion step by step.

Sternin, Edward

2006-04-14

164

Neural networks in human motion tracking - An experimental study  

Microsoft Academic Search

A novel application of neural networks is proposed for tracking the motion of a walking pedestrian. First, the motion is summarized by trajectories consisting of sequences of state vectors, each vector defining a 2D shape contour as well as the position of the pedestrian in image coordinates. Next, the task of tracking the motion is conducted in the context of

Li-qun Xu; David C. Hogg

1997-01-01

165

Simple building reconstruction from LIDAR point cloud  

Microsoft Academic Search

This paper presents a method for simple regular building reconstruction from LIDAR point cloud. At First, TIN model of the extracted building point from discrete LIDAR point cloud is built. Those points in triangle facet which having the similar normal vector value are clustered into the same plane point set. Then, every plane point set is fitted into plane using

Qihong Zeng; Jiazhen Lai; Xianhua Li; Jianhua Mao; Xuefeng Liu

2008-01-01

166

Bidirectional motion tracking for video indexing  

Microsoft Academic Search

Motion is recognized as one of the most essential video object (VO) features in indexing video contents. Previously, we directly exploited macroblock motion vectors (MVs) of MPEG bitstream without performing full decoding to extract motion trajectories of VOs. However, the performance of VO segmentation based on MVs is constrained by the limited information extracted from the MV field, since it

How-Lung Eng; Kai-Kuang Ma

1999-01-01

167

Motion Sickness  

MedlinePLUS

... people traveling by car, train, airplanes and especially boats. Motion sickness can start suddenly, with a queasy ... motion sickness. For example, down below on a boat, your inner ear senses motion, but your eyes ...

168

Complex Clouds  

article title:  Multi-layer Clouds Over the South Indian Ocean     ... Larger Image The complex structure and beauty of polar clouds are highlighted by these images acquired by the Multi-angle Imaging ...

2013-04-16

169

Cloud Computing  

SciTech Connect

Chicago Matters: Beyond Burnham (WTTW). Chicago has become a world center of "cloud computing." Argonne experts Pete Beckman and Ian Foster explain what "cloud computing" is and how you probably already use it on a daily basis.

Pete Beckman and Ian Foster

2009-12-04

170

Cloud Computing  

Microsoft Academic Search

Computing as you know it is about to change, your applications and documents are going to move from the desktop into the cloud. I'm talking about cloud computing, where applications and files are hosted on a \\

Shivaji P. Mirashe; N. V. Kalyankar

2010-01-01

171

Multiscale Cloud System Modeling  

NASA Technical Reports Server (NTRS)

The central theme of this paper is to describe how cloud system resolving models (CRMs) of grid spacing approximately 1 km have been applied to various important problems in atmospheric science across a wide range of spatial and temporal scales and how these applications relate to other modeling approaches. A long-standing problem concerns the representation of organized precipitating convective cloud systems in weather and climate models. Since CRMs resolve the mesoscale to large scales of motion (i.e., 10 km to global) they explicitly address the cloud system problem. By explicitly representing organized convection, CRMs bypass restrictive assumptions associated with convective parameterization such as the scale gap between cumulus and large-scale motion. Dynamical models provide insight into the physical mechanisms involved with scale interaction and convective organization. Multiscale CRMs simulate convective cloud systems in computational domains up to global and have been applied in place of contemporary convective parameterizations in global models. Multiscale CRMs pose a new challenge for model validation, which is met in an integrated approach involving CRMs, operational prediction systems, observational measurements, and dynamical models in a new international project: the Year of Tropical Convection, which has an emphasis on organized tropical convection and its global effects.

Tao, Wei-Kuo; Moncrieff, Mitchell W.

2009-01-01

172

The Physics Classroom: Vectors - Fundamentals and Operations  

NSDL National Science Digital Library

This interactive tutorial provides comprehensive help and practice in understanding vector quantities. It is organized into six sections: vector direction, vector addition, resultants, components, vector resolution, and component addition. It closes with relative velocity and riverboat problems, plus a discussion of the interdependence of perpendicular components of motion. Each section explains a topic and provides exercises for learner self-assessment. Images, animations, and graphs are placed throughout to illustrate the concepts. Editor's Note: Fluency in vector operations requires practice, and this tutorial provides it. Additional guidance is offered by clicking "Student Extras" at the top of the tutorial page.

Henderson, Tom

173

Cloning vector  

DOEpatents

A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.

Guilfoyle, R.A.; Smith, L.M.

1994-12-27

174

Cloud Types  

NSDL National Science Digital Library

This resource describes cloud formation and explains atmospheric processes such as convection, evaporation, and transpiration. The discussion includes how clouds form, some of their properties, and how precipitation is triggered. A multimedia interactive feature explains how clouds are named and identified. Questions for discussion are provided.

2005-01-01

175

Cloud Types  

NSDL National Science Digital Library

This tutorial explains common cloud classifications and the Latin root words that have been adapted to create the various names of clouds. The classification is subdivided into high-, low-, and mid-level types, clouds with vertical development, and other, less common types. Each description is accompanied by an example photograph.

2005-03-10

176

Enhanced Cloud Disruption by Magnetic Field Interaction  

NASA Astrophysics Data System (ADS)

We present results from the first three-dimensional numerical simulations of moderately supersonic cloud motion through a tenuous, magnetized medium. We show that the interaction of the cloud with a magnetic field perpendicular to its motion has a great dynamical impact on the development of instabilities at the cloud surface. Even for initially spherical clouds, magnetic field lines become trapped in surface deformations and undergo stretching. The consequent field amplification that occurs there and, in particular, its variation across the cloud face then dramatically enhance the growth rate of Rayleigh-Taylor unstable modes, hastening the cloud disruption. Animations and color images from this work have been posted at http://www.msi.umn.edu/Projects/twj/mhd3d/.

Gregori, G.; Miniati, Francesco; Ryu, Dongsu; Jones, T. W.

1999-12-01

177

Cloud Fun  

NSDL National Science Digital Library

In this activity, each student will be given the opportunity to create their own cumulus cloud out of white paper and mount it on blue paper. Students will also complete the Cloud Fun Student Activity Sheet that includes a description of the cloud and what the weather was like on the day the cloud was observed. Uses commonly available or inexpensive materials (blank wall chart paper, newspaper, construction paper, glue, markers or pencils). This is the 1st of 3 sets of learning activities that are companion activities to the Elementary GLOBE children's book, Do You Know That Clouds Have Names? Includes a teacher implementation guide.

178

Vortices in dust clouds under microgravity: A simple explanation.  

PubMed

Clouds of dust particles in radio frequency discharges often show a periodic vortexlike motion, especially near the edges of the electrodes or near the tip of an electrostatic probe. These vortices often last as long as the discharge is powered. In a previous paper we have followed a small number of individual dust particles in a discharge under microgravity conditions, moving under the influence of forces computed by means of a self-consistent two-dimensional hydrodynamic model, and interacting via a screened Coulomb potential. The resulting motion showed the vortexlike rotation. In this paper we discuss this phenomenon in more detail, using a simplified model with harmonic forces, but extending the simulations to three dimensions. Stable vortices are observed, which show a more chaotic behavior than in the two-dimensional situation. Particles frequently jump up and down between two counterrotating vortices. The generation of the vortices can be ascribed to a nonzero rotation of the net global force vector field, which is the sum of the ion drag force, the electric force, and the thermophoretic force in case of the experiments. Comparison of experimental data with simulations using a model potential may open a way to unravel the forces inside a cloud of dust particles. PMID:14682994

Goedheer, W J; Akdim, M R

2003-10-01

179

Resynchronization of motion compensated video affected by ATM cell loss  

Microsoft Academic Search

Techniques for resynchronizing motion-compensation-based coders and strategies for the recovery of lost motion vectors are discussed. Leaky-difference resynchronization yields perceptually pleasing video sequences even at fairly high cell loss rates. Future study is needed to determine optimal data-dependent or network-state-dependent conditional resynchronization strategies. Lost motion vectors can be predicted accurately with either the median of intraframe neighboring vectors or the

Paul Haskell; D. Messerschmitt

1992-01-01

180

Motion Commotion  

NSDL National Science Digital Library

Students learn why and how motion occurs and what governs changes in motion, as described by Newton's three laws of motion. They gain hands-on experience with the concepts of forces, changes in motion, and action and reaction. In an associated literacy activity, students design a behavioral survey and learn basic protocol for primary research, survey design and report writing.

Integrated Teaching And Learning Program

181

Microphysical modeling of clouds in Titan's atmosphere  

NASA Astrophysics Data System (ADS)

Theoretical arguments point to and recent observations confirm the existence of clouds in Titan's atmosphere, yet we possess very little data on their size, composition, location and formation mechanism. A time- dependent microphysical model is used to study the evolution of ice clouds in Titan's atmosphere. The model simulates nucleation, condensational growth, evaporation, coagulation, and transport of particles in a column of atmosphere. Voyager temperature and density profiles are used to create Titan conditions. Additional data is provided through lab measurements, particularly the nucleation parameters for ethane, methane, and tholin combinations (where tholin refers a laboratory-created analog for Titan's haze particles). A variety of cloud compositions are studied, including pure ethane clouds, pure methane clouds, and mixed methane- ethane clouds (all with tholin cores). Model results are run through a radiative transfer model to determine the impact of the clouds on Titan's albedo. The abundance of methane cloud particles is limited by the number of ethane nuclei rather than the number of tholins. The condensation of methane onto these mixed cloud particles is sufficient to keep the methane close to saturation. Typical methane supersaturations are of order 0.06 on the average, however dynamically induced temperature changes can produce time varying supersaturations. Cloud production does not require a continuous surface source of methane. However, clouds produced by mean motions are not the visible methane clouds seen in recent HST and ground-based observations. Ethane clouds in the troposphere almost instantaneously nucleate methane to form mixed clouds. However, a thin ethane ‘haze’ remains just above the tropopause for some scenarios and the mixed clouds at the tropopause remain ?50% ethane by mass. Also, evaporation of methane on the mixed cloud particles near the surface leaves a thicker layer of ethane cloud particles at ˜10 km. Short-lived optically thick clouds can be created sporadically by dynamically driven atmospheric cooling. Horizontal quasi-barotropic motions are more likely to drive the supersaturation creating these clouds than are vertical motions. We expect to find these optically thick, mostly methane clouds at the pole where they can be observed by the VIMS, ISS and CIRS instruments on the Cassini orbiter. Additional instruments on the Cassini orbiter, such as UVIS and the Cassini Radar, will provide useful constraints on the input parameters in our microphysics model.

Barth, Erika L.

2004-12-01

182

EDITORIAL: Focus on Cloud Physics FOCUS ON CLOUD PHYSICS  

NASA Astrophysics Data System (ADS)

Cloud physics has for a long time been an important segment of atmospheric science. It is common knowledge that clouds are crucial for our understanding of weather and climate. Clouds are also interesting by themselves (not to mention that they are beautiful). Complexity is hidden behind the common picture of these beautiful and interesting objects. The typical school textbook definition that a cloud is 'a set of droplets or particles suspended in the atmosphere' is not adequate. Clouds are complicated phenomena in which dynamics, turbulence, microphysics, thermodynamics and radiative transfer interact on a wide range of scales, from sub-micron to kilometres. Some of these interactions are subtle and others are more straightforward. Large and small-scale motions lead to activation of cloud condensation nuclei, condensational growth and collisions; small changes in composition and concentration of atmospheric aerosol lead to significant differences in radiative properties of the clouds and influence rainfall formation. It is justified to look at a cloud as a composite, nonlinear system which involves many interactions and feedback. This system is actively linked into a web of atmospheric, oceanic and even cosmic interactions. Due to the complexity of the cloud system, present-day descriptions of clouds suffer from simplifications, inadequate parameterizations, and omissions. Sometimes the most fundamental physics hidden behind these simplifications and parameterizations is not known, and a wide scope of view can sometimes prevent a 'microscopic', deep insight into the detail. Only the expertise offered by scientists focused on particular elementary processes involved in this complicated pattern of interactions allows us to shape elements of the puzzle from which a general picture of clouds can be created. To be useful, every element of the puzzle must be shaped precisely. This often creates problems in communication between the sciences responsible for shaping elements of the puzzle, and those which combine them. Scales, assumptions and the conditions used in order to describe a particular single process of interest must be consistent with the conditions in clouds. The papers in this focus issue of New Journal of Physics collectively demonstrate (i) the variation in scientific approaches towards investigating cloud processes, (ii) the various stages of shaping elements of the puzzle, and (iii) some attempts to put the pieces together. These papers present just a small subset of loosely arranged elements in an initial stage of puzzle creation. Addressed by this issue is one of the important problems in our understanding of cloud processes—the interaction between cloud particles and turbulence. There is currently a gap between the cloud physics community and scientists working in wind tunnels, on turbulence theory and particle interactions. This collection is intended to narrow this gap by bringing together work by theoreticians, modelers, laboratory experimentalists and those who measure and observe actual processes in clouds. It forms a collage of contributions showing various approaches to cloud processes including: • theoretical works with possible applications to clouds (Bistagnino and Boffetta, Gustavsson et al), • an attempt to construct a phenomenological description of clouds and rain (Lovejoy and Schertzer), • simplified models designed to parameterize turbulence micro- and macro-effects (Celani et al, Derevyanko et al), • focused theoretical research aimed at particular cloud processes (Ayala et al, parts I and II, Wang et al), • laboratory and modeling studies of complex cloud processes (Malinowski et al). This collage is far from being complete but, hopefully, should give the reader a representative impression of the current state of knowledge in the field. We hope it will be useful to all scientists whose work is inspired by cloud processes. Focus on Cloud Physics Contents The development of ice in a cumulus cloud over southwest England Yahui Huang, Alan M Blyth, Philip R A Brown, Tom W Choularton,

Falkovich, Gregory; Malinowski, Szymon P.

2008-07-01

183

Fast full search motion estimation algorithm using various matching scans in video coding  

Microsoft Academic Search

To reduce the amount of computation in a full search (FS) algorithm for fast motion estimation, we propose a novel and fast FS motion estimation algorithm. The computational reduction without any degradation in the predicted image comes from fast elimination of impossible motion vectors. We obtain faster elimination of inappropriate motion vectors using efficient matching units from localization of the

Jong-Nam Kim; Sung-Cheal Byun; Byung-Ha Ahn

2001-01-01

184

Navigational Vectors  

NSDL National Science Digital Library

This is a high school instructional unit that features nine lessons relating to vectors. Users build understanding of vector properties as they learn airplane navigation. Problem-based learning activities include reading real-time weather maps, tracking airplanes flying in U.S. skies, calculating vector components, analyzing effects of wind velocity, and completing training similar to a private pilot certification program. The unit culminates with a pilot flight test. Participants also have access to help from experts at the Polaris Career Center. Comprehensive teacher guides, student guides , reference materials, and assessments are included. This resource was developed by the Center for Innovation in Science and Engineering Education (CIESE). Participation is cost-free with teacher registration.

2008-12-10

185

Efficient motion field representation using JBIG approach for video compression  

NASA Astrophysics Data System (ADS)

In this study, a simple and efficient scheme to improve the compression ratio of the block-based motion fields in the video compressing is proposed. In the proposed scheme, each motion field is represented by a small set of coded motion vectors and a binary bitmap. Some of the motion vectors in a motion field, named as significant motion vectors (SMVs), have the property of being significantly different from the motion vectors of their spatial or temporal adjacent blocks. Instead of coding all the motion vectors in a motion field, only the SMVs need to be coded in the proposed scheme. For each block in a frame, one bit, corresponding to its position on the binary bitmap, is used to record if the motion vector is significant or not. And then, the joint bilevel image experts group (JBIG) image coding standard is applied on the bitmap to improve the bit-rate. The experimental results reveal that more than half of the motion vectors are non-significant and can be omitted on coding procedure. Although there exists an overhead of JBIG coded binary bitmap, the coding improvement ratio of the proposed scheme is over 40% on average when comparing with the conventional variable length coding (VLC) scheme.

Tseng, Shou-Yi

2002-09-01

186

Vector carpets  

SciTech Connect

Previous papers have described a general method for visualizing vector fields that involves drawing many small ``glyphs`` to represent the field. This paper shows how to improve the speed of the algorithm by utilizing hardware support for line drawing and extends the technique from regular to unstructured grids. The new approach can be used to visualize vector fields at arbitrary surfaces within regular and unstructured grids. Applications of the algorithm include interactive visualization of transient electromagnetic fields and visualization of velocity fields in fluid flow problems.

Dovey, D.

1995-03-22

187

Operational implications of a cloud model simulation of space shuttle exhaust clouds in different atmospheric conditions  

NASA Technical Reports Server (NTRS)

A three-dimensional cloud model was used to characterize the dominant influence of the environment on the Space Shuttle exhaust cloud. The model was modified to accept the actual heat and moisture from rocket exhausts and deluge water as initial conditions. An upper-air sounding determined the ambient atmosphere in which the cloud would grow. The model was validated by comparing simulated clouds with observed clouds from four actual Shuttle launches. Results are discussed with operational weather forecasters in mind. The model successfully produced clouds with dimensions, rise, decay, liquid water contents, and vertical motion fields very similar to observed clouds whose dimensions were calculated from 16 mm film frames. Once validated, the model was used in a number of different atmospheric conditions ranging from very unstable to very stable. Wind shear strongly affected the appearance of both the ground cloud and vertical column cloud. The ambient low-level atmospheric moisture governed the amount of cloud water in model clouds. Some dry atmospheres produced little or no cloud water. An empirical forecast technique for Shuttle cloud rise is presented and differences between natural atmospheric convection and exhaust clouds are discussed.

Zak, J. A.

1989-01-01

188

Segmentation and recognition of motion capture data stream by classification  

Microsoft Academic Search

Three dimensional human motions recorded by motion capture and hand gestures recorded by using data gloves generate variable-length data streams. These data streams usually have dozens of attributes, and have dieren t variations for similar motions. To segment and recognize motion streams, a classication- based approach is proposed in this paper. Classication feature vectors are extracted by utilizing singular value

Chuanjun Li; Punit R. Kulkarni; B. Prabhakaran

2007-01-01

189

Cloud Types  

NSDL National Science Digital Library

This table provides a quick reference to cloud types. Clouds are divided into groups mainly based on the height of the cloud's base above the Earth's surface. The table further divides the types according to group, atmospheric layer, and base height. Links to additional information are embedded in the text, and users can select beginner, intermediate, or advanced levels of difficulty. A Spanish translation is available.

190

Cloud Computing  

Microsoft Academic Search

Cloud computing is an emerging computing and business model where users can gain access to their applications from anywhere\\u000a through their connected devices. The proliferation of intelligent mobile devices, high speed wireless connectivity, and rich\\u000a browser-based Web 2.0 interfaces have made this shared network-based cloud computing model possible. Cloud Computing is very\\u000a much driven by the increasingly unmanageable IT complexity.

George Wang

2009-01-01

191

Investigating Clouds  

NSDL National Science Digital Library

This field activity has two parts: Elementary school students are asked to draw and verbally describe clouds and are given web access to cloud pictures. High school students are taken outdoors to describe cloud height, shape, and cover; and wind speed before answering questions. The activity is part of the Atmospheric Visualization Collection (AVC), which focuses on data from the Atmospheric Radiation Measurement (ARM) program.

2003-05-09

192

Vectorial elements for the Galactic disc tide effects in cometary motion  

NASA Astrophysics Data System (ADS)

The classical Matese-Whitman theory of Oort Cloud comet perturbations has been revisited and extended. An explicit solution for the motion of the mean ascending node is given; it involves an elliptic integral of the third kind. Equations of the mean orbit are formulated in terms of the Cartesian components of the Laplace and angular momentum vectors (vectorial elements). The equations are solved in terms of elliptic functions and the solution is free of the ambiguity related to the orientation of the perihelion that was present in previous work. The Cartesian equations of motion for the vectorial elements form a Hamiltonian system of the Lie-Poisson type. This allows them to be integrated numerically by means of Hamiltonian splitting methods. The formulae of such an integrator are derived with a Hamiltonian function split into two parts.

Breiter, S.; Ratajczak, R.

2005-12-01

193

Investigation of arc cloud lines  

NASA Technical Reports Server (NTRS)

The natural mechanisms that lead to the development of deep convective storms through the integration of radio scan satellite data with research aircraft observations is discussed. The aircraft measurements are designed to provide detailed air motion and thermodynamic data near and in the arc cloud line region at the same time GOES rapid scan data is taken. Inspection of the data indicates: (1) Arc cloud lines are important in both the production of convergence and vorticity, and in the interaction with intense thunderstorms which may act to trigger tornado activity. (2) The lateral extent of the vertical motion field compared to the cloud scale indicates that the main driving force for the initial cloud development along the arc-line is controlled by the thunderstorm outflow(s) interacting with the convectively unstable air of the environment. (3) Arc cloud lines and their associated DSL region can pose extreme hazards to aircraft operations. (4) An arc cloud line's major threat to space shuttle operations lie in its ability to generate new thunderstorm activity along the shuttle glide path.

Purdom, J. F. W.; Sinclair, P. C.

1984-01-01

194

Diurnal polar motion  

NASA Technical Reports Server (NTRS)

An analytical theory is developed to describe diurnal polar motion in the earth which arises as a forced response due to lunisolar torques and tidal deformation. Doodson's expansion of the tide generating potential is used to represent the lunisolar torques. Both the magnitudes and the rates of change of perturbations in the earth's inertia tensor are included in the dynamical equations for the polar motion so as to account for rotational and tidal deformation. It is found that in a deformable earth with Love's number k = 0.29, the angular momentum vector departs by as much as 20 cm from the rotation axis rather than remaining within 1 or 2 cm as it would in a rigid earth. This 20 cm separation is significant in the interpretation of submeter polar motion observations because it necessitates an additional coordinate transformation in order to remove what would otherwise be a 20 cm error source in the conversion between inertial and terrestrial reference systems.

Mcclure, P.

1973-01-01

195

A cloud model simulation of space shuttle exhaust clouds in different atmospheric conditions  

NASA Technical Reports Server (NTRS)

A three-dimensional cloud model was used to characterize the dominant influence of the environment on the Space Shuttle exhaust cloud. The model was modified to accept the actual heat and moisture from rocket exhausts and deluge water as initial conditions. An upper-air sounding determined the ambient atmosphere in which the cloud could grow. The model was validated by comparing simulated clouds with observed clouds from four actual Shuttle launches. The model successfully produced clouds with dimensions, rise, decay, liquid water contents and vertical motion fields very similar to observed clouds whose dimensions were calculated from 16 mm film frames. Once validated, the model was used in a number of different atmospheric conditions ranging from very unstable to very stable. In moist, unstable atmospheres simulated clouds rose to about 3.5 km in the first 4 to 8 minutes then decayed. Liquid water contents ranged from 0.3 to 1.0 g kg-1 mixing ratios and vertical motions were from 2 to 10 ms-1. An inversion served both to reduce entrainment (and erosion) at the top and to prevent continued cloud rise. Even in the most unstable atmospheres, the ground cloud did not rise beyond 4 km and in stable atmospheres with strong low level inversions the cloud could be trapped below 500 m. Wind shear strongly affected the appearance of both the ground cloud and vertical column cloud. The ambient low-level atmospheric moisture governed the amount of cloud water in model clouds. Some dry atmospheres produced little or no cloud water. One case of a simulated TITAN rocket explosion is also discussed.

Chen, C.; Zak, J. A.

1989-01-01

196

Shapes of Bubbles and Drops in Motion.  

ERIC Educational Resources Information Center

Explains the shape distortions that take place in fluid packets (bubbles or drops) with steady flow motion by using the laws of Archimedes, Pascal, and Bernoulli rather than advanced vector calculus. (WRM)

O'Connell, James

2000-01-01

197

Motion warping  

Microsoft Academic Search

We describe a simple technique for editing captured or keyframed animation based on warping of the motion parameter curves. The animator interactively defines a set of keyframe-like constraints which are used to derive a smooth deformation that preserves the fine structure of the original motion. Motion clips are combined by overlapping and blending of the parameter curves. We show that

Andrew P. Witkin; Zoran Popovic

1995-01-01

198

Zero-gravity cloud physics.  

NASA Technical Reports Server (NTRS)

The first results of an ongoing preliminary-concept and detailed-feasibility study of a zero-gravity earth-orbital cloud physics research facility are reviewed. Current planning and thinking are being shaped by two major conclusions of this study: (1) there is a strong requirement for and it is feasible to achieve important and significant research in a zero-gravity cloud physics facility; and (2) some very important experiments can be accomplished with 'off-the-shelf' type hardware by astronauts who have no cloud-physics background; the most complicated experiments may require sophisticated observation and motion subsystems and the astronaut may need graduate level cloud physics training; there is a large number of experiments whose complexity varies between these two extremes.

Hollinden, A. B.; Eaton, L. R.; Vaughan, W. W.

1972-01-01

199

Cloud Control  

ERIC Educational Resources Information Center

Your learning curriculum needs a new technological platform, but you don't have the expertise or IT equipment to pull it off in-house. The answer is a learning system that exists online, "in the cloud," where learners can access it anywhere, anytime. For trainers, cloud-based coursework often means greater ease of instruction resulting in greater…

Weinstein, Margery

2012-01-01

200

Cloud Computing  

Microsoft Academic Search

Computing as you know it is about to change, your applications and documents\\u000aare going to move from the desktop into the cloud. I'm talking about cloud\\u000acomputing, where applications and files are hosted on a \\

Shivaji P. Mirashe; N. V. Kalyankar; Benjamin Blau; Nikolay Borissov; Thomas Meinl; Wibke Michalk; Jochen Stößer

2009-01-01

201

Low Clouds  

article title:  Indian Ocean Clouds     View Larger Image This image of clouds over the southern Indian Ocean was acquired on July 23, 2007 by one of the backward (northward)-viewing ... NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed ...

2013-04-19

202

Arctic mixed-phase summer clouds: Lessons from ASCOS  

NASA Astrophysics Data System (ADS)

As part of the 2007-2009 International Polar Year, the 2008 Arctic Summer Cloud and Ocean Study (ASCOS) experiment gathered detailed observations of the autumn central Arctic troposphere, boundary layer and surface energy budget, with an emphasis on how mixed-phase clouds impact the system. This presentation provides an overview of results from ASCOS examining the interactions between thermodynamics, boundary layer structure and dynamic motions generated within mixed-phase clouds. Over the Arctic Ocean, mixed-phase clouds in the lower troposphere occur frequently. These clouds exert the largest, most critical component on the surface energy budget via interactions with radiative fluxes. The surface cloud-radiative effect has the potential to control the sign and magnitude of the surface energy residual (positive - melting, or negative - freezing) and the boundary layer stability. Despite a common near-neutrally stratified boundary layer up to below ~ 500 m, mixed-phase clouds were most frequently found to be decoupled from the surface. Cloud-generated vertical motions produced via radiative divergence near cloud top produce mixing across the cloud layer and into the sub-cloud layer. The extent at which these motions couple with the surface mixed-layer correlates positively with liquid water path, cloud base height and cloud thickness; all of these factors affect the strength of vertical motions produced by the cloud layer. Persistence of the cloud is attributed to moisture inversions co-located with temperature inversions, often characterizing the upper third of the cloud layers. In-cloud vertical velocity characteristics derived from cloud radar shows a unique vertical structure that corresponds with the thermodynamic structure within the cloud. Despite cloud penetration within the stable, yet moist, temperature inversion, we show that peak cloud-generated vertical velocity overturning time scales are surprisingly similar and coherent across three levels within cloud; additionally velocity overturning time scales are similar regardless of coupling between the cloud-surface system. These findings help to better understand the resilience of Arctic mixed-phase clouds.

Tjernström, Michael; Sedlar, Joseph; Brooks, Ian; Persson, Ola; Shupe, Matthew

2014-05-01

203

Ionization and expansion of barium clouds in the ionosphere  

NASA Technical Reports Server (NTRS)

A recently envelope 3D model is used here to study the motion of the barium clouds released in the ionosphere, including the ionization stage. The ionization and the expansion of the barium clouds and the interaction between the clouds and the background ions are investigated using three simulations: a cloud without a directional velocity, a cloud with an initial velocity of 5 km/s across the B field, and a cloud with initial velocity components of 2 km/s both along and across the B field.

Ma, T.-Z.; Schunk, R. W.

1993-01-01

204

Plate motion  

SciTech Connect

The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

Gordon, R.G. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

205

Angular Motion of Spinning Almost Symmetric Missiles.  

National Technical Information Service (NTIS)

An almost symmetric missile is a missile whose zero-spin pitch and yaw frequencies are 'nearly' equal. The angular motion of a spinning almost symmetric missile can be described by five rotating modal vectors. Two of these vectors vanish when the frequenc...

C. H. Murphy

1978-01-01

206

Characteristic nature of vertical motions observed in Arctic mixed-phase stratocumulus  

NASA Astrophysics Data System (ADS)

Over the Arctic Ocean, little is known on cloud-generated buoyant overturning vertical motions within mixed-phase stratocumulus clouds. Characteristics of such motions are important for understanding the diabatic processes associated with the vertical motions, the lifetime of the cloud layer and its micro- and macrophysical characteristics. In this study, we exploit a suite of surface-based remote sensors over the high-Arctic sea ice during a weeklong period of persistent stratocumulus in August 2008 to derive the in-cloud vertical motion characteristics. In-cloud vertical velocity skewness and variance profiles are found to be strikingly different from observations within lower-latitude stratocumulus, suggesting these Arctic mixed-phase clouds interact differently with the atmospheric thermodynamics (cloud tops extending above a stable temperature inversion base) and with a different coupling state between surface and cloud. We find evidence of cloud-generated vertical mixing below cloud base, regardless of surface-cloud coupling state, although a decoupled surface-cloud state occurred most frequently. Detailed case studies are examined, focusing on three levels within the cloud layer, where wavelet and power spectral analyses are applied to characterize the dominant temporal and horizontal scales associated with cloud-generated vertical motions. In general, we find a positively correlated vertical motion signal amongst vertical levels within the cloud and across the full cloud layer depth. The coherency is dependent upon other non-cloud controlled factors, such as larger, mesoscale weather passages and radiative shielding of low-level stratocumulus by one or more cloud layers above. Despite the coherency in vertical velocity across the cloud, the velocity variances were always weaker near cloud top, relative to cloud middle and base. Taken in combination with the skewness, variance and thermodynamic profile characteristics, we observe vertical motions near cloud top that behave differently than those from lower within the cloud layer. Spectral analysis indicates peak cloud-generated w variance timescales slowed only modestly during decoupled cases relative to coupled; horizontal wavelengths only slightly increased when transitioning from coupling to decoupling. The similarities in scales suggests that perhaps the dominant forcing for all cases is generated from the cloud layer, and it is not the surface forcing that characterizes the time- and space scales of in-cloud vertical velocity variance. This points toward the resilient nature of Arctic mixed-phase clouds to persist when characterized by thermodynamic regimes unique to the Arctic.

Sedlar, J.; Shupe, M. D.

2014-04-01

207

Walter Fendt Physics Applets: Projectile Motion  

NSDL National Science Digital Library

This Java applet demonstrates projectile motion. Set the initial speed, height, and mass of the projectile, the initial angle of the velocity, and the gravitational constant -- and view the resulting motion. Display options available include force vectors and potential/kinetic energies. This resource is part of a large collection of physics applets available in a wide range of languages.

Fendt, Walter

2007-02-05

208

Ice in Volcanic Clouds  

NASA Astrophysics Data System (ADS)

It is widely recognized that lightning activity in thunderstorm clouds is associated with ice in the clouds. In volcanic plumes the lower electrical discharges near the vent are clearly not associated with ice; however, the electrical discharges from the upper volcanic clouds very likely are associated with ice. There is ample water in volcanic plumes and clouds. The explosive volcanic eruption is produced by volatile components in the rising magma. Researchers estimate that the water content of the volatiles is up to 99% by mole; other gases are mainly sulfur and chlorine species. These volatiles carry with them a wide range of hot magma melts and solids, importantly silicate particles and tephra. The more massive components fall out near the vent carrying with them much of the heat from the plume; these large components are not in thermodynamic equilibrium with the gases, ash, and lapilli; thus the heat removed does not lower the temperature of the materials carried aloft in the plume. Upward motion is initially provided by the thrust from the volcanic eruption, then by buoyancy of the hot plume. The rising plume is cooled by entrainment of environmental air, which contains water, and by adiabatic expansion; the plume transitions into a volcanic cloud. Further lifting and cooling produces supercooled water droplets (T ~ -5 C) in a limited zone (z ~ 9 km) before the fast updraft (~ 60 m/s) rapidly transforms them into ice. Computer models of volcanic clouds that include water and ice microphysics indicate that the latent heat of condensation is not significant in cloud dynamics because it occurs in a region where buoyancy is provided by the original hot plume material. The latent heat of ice formation occurs at higher and colder levels and seems to contribute to the final lifting of the cloud top by ~1.5km. Laboratory results indicate that the fine silicate ash particles, which are abundant, are good ice nuclei, IN. Because of the abundance of the silicate ash, modelers conclude that there are many small ice particles in a volcanic clouds compared to thunderstorm clouds where the scarcity of IN produce fewer but larger ice particles. Another microphysical difference is that in the water phase (drops or ice surface) adsorption of sulfur and chlorine gases is enhanced and the freezing temperature lowered. During diffusion growth of ice particles sulfur dioxide can be incorporated in the ice. The sulfur dioxide sequestered by the ice can be converted to sulfate and transported into the stratosphere and released when the ice sublimates. Do these microphysical differences significantly alter the electrical charging mechanisms that exist in thunderstorm clouds? Observations of the lightning discharges associated with the upper regions of volcanic clouds seem to indicate that the charging mechanisms are essentially the same.

Few, A. A.

2010-12-01

209

Characteristic nature of vertical motions observed in Arctic mixed-phase stratocumulus  

NASA Astrophysics Data System (ADS)

Over the Arctic Ocean, little is known, observationally, on cloud-generated buoyant overturning vertical motions within mixed-phase stratocumulus clouds. Characteristics of such motions are important for understanding the diabatic processes associated with the vertical motions, the lifetime of the cloud layer and its micro- and macrophysical characteristics. In this study, we exploit a suite of surface-based remote sensors over the high Arctic sea ice during a week-long period of persistent stratocumulus in August 2008 to derive the in-cloud vertical motion characteristics. In-cloud vertical velocity skewness and variance profiles are found to be strikingly different from observations within lower-latiatude stratocumulus, suggesting these Arctic mixed-phase clouds interact differently with the atmospheric thermodynamics (cloud tops extending above a stable temperature inversion base) and with a different coupling state between surface and cloud. We find evidence of cloud-generated vertical mixing below cloud base, regardless of surface-cloud coupling state, although a decoupled surface-cloud state occurred most frequently. Detailed case studies are examined focusing on 3 levels within the cloud layer, where wavelet and power spectral analyses are applied to characterize the dominant temporal and horizontal scales associated with cloud-generated vertical motions. In general, we find a positively-correlated vertical motion signal across the full cloud layer depth. The coherency is dependent upon other non-cloud controlled factors, such as larger, mesoscale weather passages and radiative shielding of low-level stratocumulus by multiple cloud layers above. Despite the coherency in vertical velocity across the cloud, the velocity variances were always weaker near cloud top, relative to cloud mid and base. Taken in combination with the skewness, variance and thermodynamic profile characteristics, we observe vertical motions near cloud-top that behave differently than those from lower within the cloud layer. Spectral analysis indicates peak cloud-generated w variance timescales slowed only modestly during decoupled cases relative to coupled; horizontal wavelengths only slightly increased when transitioning from coupling to decoupling. The similarities in scales suggests that perhaps the dominant forcing for all cases is generated from the cloud layer, and it is not the surface forcing that characterizes the time and space scales of in-cloud vertical velocity variance. This points toward the resilient nature of Arctic mixed-phase clouds to persist when characterized by thermodynamic regimes unique to the Arctic.

Sedlar, J.; Shupe, M. D.

2013-11-01

210

Animating Motion  

NSDL National Science Digital Library

This lesson challenges students to apply their knowledge of object motion by animating sequences of hand-rendered pictures that model a set of physical conditions. The challenges include animating the orbital motion of planets and satellites, the effects of gravity on a falling body, and motions of objects in inertial (moving) frames of reference. The lesson was created by a high school physics teacher to help learners build quantitative reasoning skills in preparation for understanding kinematics.

Latham, Ted

2004-07-16

211

Cloud Games  

NSDL National Science Digital Library

Play these two matching games from the Web Weather for Kids site to pair cloud images with their names/types! Developed by the University Corporation for Atmospheric Research, this site requires Java.

Programs, University C.

2010-01-01

212

VLSI recursive motion estimator chip set  

Microsoft Academic Search

The design of a VLSI chip set implementing a recursive motion estimator (ME) for video applications is described. This chip set can be used to compress the information of a full-motion video source for applications where low-bit-rate or very-low-bit-rate coding is required. The ME block provides for a set of motion vectors describing the displacement of two consecutive frames. The

S. Brofferio; M. Monti; V. Rampa; M. Taliercio

1990-01-01

213

CLOUD CONDENSATION NUCLEI MEASUREMENTS WITHIN CLOUDS  

EPA Science Inventory

Measurements of the spectra of cloud condensation nuclei (CCN) within and near the boundaries of clouds are presented. Some of the in-cloud measurements excluded the nuclei within cloud droplets (interstitial CCN) while others included all nuclei inside the cloud (total CCN). The...

214

Motion Simulator  

NASA Technical Reports Server (NTRS)

Visitors to StenniSphere can feel the motion of a ride to Mars with a ride on StenniSphere's full motion simulator. The simulator is the only attraction at StenniSphere for which there is a charge. Adult rides are $4 and children ride for $3. Group discounts are also available.

2000-01-01

215

Kepler Motion  

NSDL National Science Digital Library

This website, from the National Taiwan Normal University, provides a demonstration of Kepler's laws of planetary motion. The site offers a description of all three laws and a brief history of Johann Kepler and his discoveries. The applet can be adjusted to display several different variables of planetary motion to simulate each law effectively.

Hwang, Fu-Kwun

2008-10-28

216

Interaction of a neutral cloud moving through a magnetized plasma  

NASA Technical Reports Server (NTRS)

Current collection by outgassing probes in motion relative to a magnetized plasma may be significantly affected by plasma processes that cause electron heating and cross field transport. Simulations of a neutral gas cloud moving across a static magnetic field are discussed. The authors treat a low-Beta plasma and use a 2-1/2 D electrostatic code linked with the authors' Plasma and Neutral Interaction Code (PANIC). This study emphasizes the understanding of the interface between the neutral gas cloud and the surrounding plasma where electrons are heated and can diffuse across field lines. When ionization or charge exchange collisions occur a sheath-like structure is formed at the surface of the neutral gas. In that region the crossfield component of the electric field causes the electron to E times B drift with a velocity of the order of the neutral gas velocity times the square root of the ion to electron mass ratio. In addition a diamagnetic drift of the electron occurs due to the number density and temperature inhomogeneity in the front. These drift currents excite the lower-hybrid waves with the wave k-vectors almost perpendicular to the neutral flow and magnetic field again resulting in electron heating. The thermal electron current is significantly enhanced due to this heating.

Goertz, C. K.; Lu, G.

1990-01-01

217

Tectonic Plate Motion  

NSDL National Science Digital Library

The representation shows the direction of motion of the Earth's major plates as measured through NASA's satellite laser ranging (SLR) technology. A series of world maps, accompanying text, and the subsequent links explain this technology in great detail. One can click on the Index Map for Satellite Laser Ranging site Velocity and see the vectors (arrows) that indicate the direction and rate of movement of Earth's plates in much more detail. Accompanying text gives a more detailed explanation of what each sub map is showing.

218

The meteorology of giant planets revealed through automated cloud feature tracking  

Microsoft Academic Search

We examine the meteorology of the giant planets using our automated cloud feature tracker. Through pattern recognition and correlation optimization, our software returns a dense, regular grid of wind vectors ideal for further analysis, in contrast with an irregular grid of relatively sparse vectors returned using manual (hand-eye) cloud tracking. We measure the winds in and around Jupiter's Great Red

David Sanghun Choi

2009-01-01

219

Cloud level winds from the Venus Express Monitoring Camera imaging  

NASA Astrophysics Data System (ADS)

Six years of continuous monitoring of Venus by European Space Agency's Venus Express orbiter provides an opportunity to study dynamics of the atmosphere our neighbor planet. Venus Monitoring Camera (VMC) on-board the orbiter has acquired the longest and the most complete so far set of ultra violet images of Venus. These images enable a study the cloud level circulation by tracking motion of the cloud features. The highly elliptical polar orbit of Venus Express provides optimal conditions for observations of the Southern hemisphere at varying spatial resolution. Out of the 2300 orbits of Venus Express over which the images used in the study cover about 10 Venus years. Out of these, we tracked cloud features in images obtained in 127 orbits by a manual cloud tracking technique and by a digital correlation method in 576 orbits. Total number of wind vectors derived in this work is 45,600 for the manual tracking and 391,600 for the digital method. This allowed us to determine the mean circulation, its long-term and diurnal trends, orbit-to-orbit variations and periodicities. We also present the first results of tracking features in the VMC near-IR images. In low latitudes the mean zonal wind at cloud tops (67 ± 2 km following: Rossow, W.B., Del Genio, A.T., Eichler, T. [1990]. J. Atmos. Sci. 47, 2053-2084) is about 90 m/s with a maximum of about 100 m/s at 40-50°S. Poleward of 50°S the average zonal wind speed decreases with latitude. The corresponding atmospheric rotation period at cloud tops has a maximum of about 5 days at equator, decreases to approximately 3 days in middle latitudes and stays almost constant poleward from 50°S. The mean poleward meridional wind slowly increases from zero value at the equator to about 10 m/s at 50°S and then decreases to zero at the pole. The error of an individual measurement is 7.5-30 m/s. Wind speeds of 70-80 m/s were derived from near-IR images at low latitudes. The VMC observations indicate a long term trend for the zonal wind speed at low latitudes to increase from 85 m/s in the beginning of the mission to 110 m/s by the middle of 2012. VMC UV observations also showed significant short term variations of the mean flow. The velocity difference between consecutive orbits in the region of mid-latitude jet could reach 30 m/s that likely indicates vacillation of the mean flow between jet-like regime and quasi-solid body rotation at mid-latitudes. Fourier analysis revealed periodicities in the zonal circulation at low latitudes. Within the equatorial region, up to 35°S, the zonal wind show an oscillation with a period of 4.1-5 days (4.83 days on average) that is close to the super-rotation period at the equator. The wave amplitude is 4-17 m/s and decreases with latitude, a feature of the Kelvin wave. The VMC observations showed a clear diurnal signature. A minimum in the zonal speed was found close to the noon (11-14 h) and maxima in the morning (8-9 h) and in the evening (16-17 h). The meridional component peaks in the early afternoon (13-15 h) at around 50°S latitude. The minimum of the meridional component is located at low latitudes in the morning (8-11 h). The horizontal divergence of the mean cloud motions associated with the diurnal pattern suggests upwelling motions in the morning at low latitudes and downwelling flow in the afternoon in the cold collar region.

Khatuntsev, I. V.; Patsaeva, M. V.; Titov, D. V.; Ignatiev, N. I.; Turin, A. V.; Limaye, S. S.; Markiewicz, W. J.; Almeida, M.; Roatsch, Th.; Moissl, R.

2013-09-01

220

The mean-square error optimal linear discriminant function and its application to incomplete data vectors  

NASA Technical Reports Server (NTRS)

In many pattern recognition problems, data vectors are classified although one or more of the data vector elements are missing. This problem occurs in remote sensing when the ground is obscured by clouds. Optimal linear discrimination procedures for classifying imcomplete data vectors are discussed.

Walker, H. F.

1979-01-01

221

Fusion of LIDAR Data and Large-scale Vector Maps for Building Reconstruction  

Microsoft Academic Search

LIDAR data contains plenty of height information, while vector maps preserve accurate building boundaries. From the viewpoint of data fusion, we integrate LIDAR data and large-scale vector maps to perform building modeling. The proposed scheme comprises six major steps: (1) preprocessing of LIDAR data and vector maps, (2) extraction of point clouds that belong to a building, (3) construction of

Liang-Chien Chen; Chih-Yi Kuo; Jiann-Yeou Rau; Chi-Heng Hsieh

222

Leadership and Self-Propelled Behavior Based Autonomous Virtual Fish Motion  

Microsoft Academic Search

This paper presents a method of shoal motion with an effective leadership of autonomous virtual fish. Shoal motion is led by a leader and computed by five steering behavior vectors including cohesion, separation, velocity, escape and goal vectors. Through experiments, we demonstrate that a leader of the motion simulation has great effect in leadership and great accuracy to guide the

Seongah Chin; Chung-yeon Lee; Seongdong Kim

2008-01-01

223

Our World: Cool Clouds  

NASA Video Gallery

Learn how clouds are formed and watch an experiment to make a cloud using liquid nitrogen. Find out how scientists classify clouds according to their altitude and how clouds reflect and absorb ligh...

224

A cross octagonal search algorithm for fast block motion estimation  

Microsoft Academic Search

A cross octagonal search algorithm (COSA) is proposed in this paper to perform block motion estimation in video sequence compression. In contrast with the classical fast block motion algorithm, cross and octagonal search pattern is adopted in search process in this algorithm. Based on the characteristic of motion vector's cross center biased distribution, the correlation of the ending points in

Liang Yaling; Liu Jing; Du Minghui

2005-01-01

225

Motion compensation for video compression using control grid interpolation  

Microsoft Academic Search

A new class of motion compensation methods that are based on control grid interpolation (CGI) for use in video compression is described. The predominant motion compensation method, block matching, is shown to be a special case of CGI. A new CGI method is presented that produces a smooth motion vector field, preserving continuity and connectivity in the prediction image. When

G. J. Sullivan; R. L. Baker

1991-01-01

226

Curious About Clouds  

NSDL National Science Digital Library

What are the characteristics of the 3 main types of clouds, and what weather does each of these clouds produce? 3 Main Types of Clouds Use this website to start learn about the 3 main types of clouds: Cumulus, Stratus, and Cirrus Use your cloud graphic organizer and fill in the three main types of clouds along with information describing them. Clouds Weather Video Watch this video to learn how clouds are formed and what happens ...

Stewart, Ms.

2010-03-24

227

Cloud denoising  

NASA Astrophysics Data System (ADS)

We address the issue of cloud removal from images. Typically a cloud on an image is not uniform and we develop methods that do denoising on a local level. In this paper we present preliminary studies of such methods and also a method for image fusion. The procedure is based on the use of a denoising pixel-level measure. The measure is defined through a 1-D Pseudo Wigner Distribution (PWD) applied to non-overlapping N-pixel window slices of the original image. The method is illustrated with different set of artificial and natural cloudy or foggy images, which are partially occluded by clouds in different regions. Another advantage of the present approach is its reduced computational cost in comparison with other methods based on a full 2-D implementation of the PWD.

Gabarda, Salvador; Cristobal, Gabriel; Galleani, Lorenzo; Cohen, Leon

2004-05-01

228

Neptune's clouds  

NASA Technical Reports Server (NTRS)

The bright cirrus-like clouds of Neptune change rapidly, often forming and dissipating over periods of several to tens of hours. In this sequence Voyager 2 observed cloud evolution in the region around the Great Dark Spot (GDS). The surprisingly rapid changes which occur separating each panel shows that in this region Neptune's weather is perhaps as dynamic and variable as that of the Earth. However, the scale is immense by our standards -- the Earth and the GDS are of similar size -- and in Neptune's frigid atmosphere, where temperatures are as low as 55 degrees Kelvin (-360 F), the cirrus clouds are composed of frozen methane rather than Earth's crystals of water ice. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications

1999-01-01

229

Vector Addition Model  

NSDL National Science Digital Library

The Vector Addition model allows the user to practice vector addition of two vectors in two dimensions. You are given the magnitude and direction of the two vectors, and your goal is to fill in the nine values in the table (showing the x-component, y-component, and length) of the two vectors, and the resultant vector that is the sum of the first two vectors. The Vector Addition was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_addition.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-25

230

Cloud Formation  

NSDL National Science Digital Library

This Classroom Connectors lesson plan teaches students how clouds are formed through the condensation of water vapor. This includes learning about climate types and how they change, the greenhouse effect, how clouds affect weather and climate, and condensation. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

231

Motion Sickness  

MedlinePLUS

... vestibular sense detects motion while their eyes are fixed on motionless surroundings. Avoid alcohol. Take over the ... better to keep your eyes focused on a fixed object. Drive. Concentrating on the road helps you ...

232

Projectile Motion  

NSDL National Science Digital Library

Blast a Buick out of a cannon! Learn about projectile motion by firing various objects. Set the angle, initial speed, and mass. Add air resistance. Make a game out of this simulation by trying to hit a target.

Simulations, Phet I.; Dubson, Michael; Adams, Wendy

2004-06-01

233

Magnetic Fields in Molecular Clouds  

NASA Astrophysics Data System (ADS)

Maps of far-infrared and submillimeter polarization vectors have typically been examined one-at-a-time for magnetic field structure related to processes such as gravitational collapse, differential rotation, expanding H II regions, or tidal stripping. The same maps can be used to determine angular dispersion due to turbulence in molecular clouds, where the turbulent dispersion is distinguished from dispersion due to curvature of the large-scale structure or the apparent dispersion due to measurement error. Taking into account the differences between the dispersion due to magneto-hydrodynamic waves in the arms of the Galaxy and dispersion due to turbulence in molecular clouds, one can infer field strengths in dense clouds using a method analogous to that used by Chandresekhar & Fermi to determine field strengths in the Galactic plane. With an accurate archive of flux and polarization maps one can also determine three-dimensional cloud shapes and field orientations, or look for correlations between fields in molecular clouds and fields in the surrounding medium.

Hildebrand, R. H.

2009-12-01

234

Vectors: Tip to Tail  

NSDL National Science Digital Library

In this lesson students will learn the characteristics and appropriate use of vectors. They will find the magnitude and direction of vectors, they will add and subtract vectors and use an interactive website to practice what they have learned.

Linamen, Sharon

2012-07-23

235

Consciousness disintegrates without conscious vectors.  

PubMed

Consciousness is discontinuous. The transition from the raw output of parallel, distributed processors into the unified, serial content of consciousness is not instantaneous. Consciousness is divided into discrete cycles, yet appears to be continuous. The continuity requires temporal integration. The simplest mechanism is the calculation of the direction and magnitude of change from one conscious cycle to the next and then the fusion of these conscious vectors with the content of subsequent cycles. This mechanism, while putative, has supporting evidence. It is based on the same mechanism as motion vision, in which motion vectors are calculated in MT/V5 and then fused with discrete images. Moreover, it is based on the known separation of cognitive timing in the brain, in which temporal integrity is maintained in the prefrontal cortex (PFC) and the rest of the content of consciousness is maintained in the rest of the cortex. In fact, limited activity of the PFC matches the predicted effects of the absence of conscious vectors: thoughts strobe and consciousness disintegrates into a series of discrete cycles. The PFC, for example, is one of the primary brain regions deactivated during dreaming, when thoughts shift without any awareness of the transitions. In addition, the PFC is immature in infants, when there is no memory of the experience of consciousness because there is no temporal integrity to assemble the discrete cycles into a coherent experience. Without temporal integration, the human brain is an advanced biological computer, but is not sentient. PMID:17630226

Bodovitz, Steven

2008-01-01

236

Diagnosis of the Net Cloud Mass Flux in Gate  

Microsoft Academic Search

A diagnostic analysis of the net cloud mass flux for the mean state of Phase III is presented. In the upper troposphere, the environmental mass flux is shown to be slightly larger than the adiabatic sinking motion required by radiative cooling. At the outflow layer of tall clouds, if the moistening effect due to detrainments is balanced primarily by the

Yi-Leng Chen

1985-01-01

237

Are Bred Vectors The Same As Lyapunov Vectors?  

NASA Astrophysics Data System (ADS)

Regional loss of predictability is an indication of the instability of the underlying flow, where small errors in the initial conditions (or imperfections in the model) grow to large amplitudes in finite times. The stability properties of evolving flows have been studied using Lyapunov vectors (e.g., Alligood et al, 1996, Ott, 1993, Kalnay, 2002), singular vectors (e.g., Lorenz, 1965, Farrell, 1988, Molteni and Palmer, 1993), and, more recently, with bred vectors (e.g., Szunyogh et al, 1997, Cai et al, 2001). Bred vectors (BVs) are, by construction, closely related to Lyapunov vectors (LVs). In fact, after an infinitely long breeding time, and with the use of infinitesimal ampli- tudes, bred vectors are identical to leading Lyapunov vectors. In practical applications, however, bred vectors are different from Lyapunov vectors in two important ways: a) bred vectors are never globally orthogonalized and are intrinsically local in space and time, and b) they are finite-amplitude, finite-time vectors. These two differences are very significant in a dynamical system whose size is very large. For example, the at- mosphere is large enough to have "room" for several synoptic scale instabilities (e.g., storms) to develop independently in different regions (say, North America and Aus- tralia), and it is complex enough to have several different possible types of instabilities (such as barotropic, baroclinic, convective, and even Brownian motion). Bred vectors share some of their properties with leading LVs (Corazza et al, 2001a, 2001b, Toth and Kalnay, 1993, 1997, Cai et al, 2001). For example, 1) Bred vectors are independent of the norm used to define the size of the perturba- tion. Corazza et al. (2001) showed that bred vectors obtained using a potential enstro- phy norm were indistinguishable from bred vectors obtained using a streamfunction squared norm, in contrast with singular vectors. 2) Bred vectors are independent of the length of the rescaling period as long as the perturbations remain approximately linear (for example, for atmospheric models the interval for rescaling could be varied between a single time step and 1 day without affecting qualitatively the characteristics of the bred vectors. However, the finite-amplitude, finite-time, and lack of orthogonalization of the BVs introduces important differences with LVs: 1) In regions that undergo strong instabilities, the bred vectors tend to be locally domi- 1 nated by simple, low-dimensional structures. Patil et al (2001) showed that the BV-dim (appendix) gives a good estimate of the number of dominant directions (shapes) of the local k bred vectors. For example, if half of them are aligned in one direction, and half in a different direction, the BV-dim is about two. If the majority of the bred vectors are aligned predominantly in one direction and only a few are aligned in a second direction, then the BV-dim is between 1 and 2. Patil et al., (2001) showed that the regions with low dimensionality cover about 20% of the atmosphere. They also found that these low-dimensionality regions have a very well defined vertical structure, and a typical lifetime of 3-7 days. The low dimensionality identifies regions where the in- stability of the basic flow has manifested itself in a low number of preferred directions of perturbation growth. 2) Using a Quasi-Geostrophic simulation system of data assimilation developed by Morss (1999), Corazza et al (2001a, b) found that bred vectors have structures that closely resemble the background (short forecasts used as first guess) errors, which in turn dominate the local analysis errors. This is especially true in regions of low dimensionality, which is not surprising if these are unstable regions where errors grow in preferred shapes. 3) The number of bred vectors needed to represent the unstable subspace in the QG system is small (about 6-10). This was shown by computing the local BV-dim as a function of the number of independent bred vectors. Convergence in the local dimen- sion starts to occur at about 6 BVs, and is essentially

Kalnay, E.; Corazza, M.; Cai, M.

238

Present-day plate motions  

NASA Technical Reports Server (NTRS)

A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to less than 3 My. A detailed comparison of RM2 with angular velocity vectors which best fit the data along individual plate boundaries indicates that RM2 performs close to optimally in most regions, with several notable exceptions. On the other hand, a previous estimate (RM1) failed to satisfy an extensive set of new data collected in the South Atlantic Ocean. It is shown that RM1 incorrectly predicts the plate kinematics in the South Atlantic because the presently available data are inconsistent with the plate geometry assumed in deriving RM1. It is demonstrated that this inconsistency can be remedied by postulating the existence of internal deformation with the Indian plate, although alternate explanations are possible.

Minster, J. B.; Jordan, T. H.

1977-01-01

239

Vectors in Use in a 3D Juggling Game Simulation  

ERIC Educational Resources Information Center

The new representations enabled by the educational computer game the "Juggler" can place vectors in a central role both for controlling and measuring the behaviours of objects in a virtual environment simulating motion in three-dimensional spaces. The mathematical meanings constructed by 13 year-old students in relation to vectors as objects, as a…

Kynigos, Chronis; Latsi, Maria

2006-01-01

240

Rate-distortion optimization between the hierarchical variable block size motion estimation and motion sequence coding  

NASA Astrophysics Data System (ADS)

Recently, a variable block size (VBS) motion estimation technique has been employed to improve the performance of the motion compensated transform coding (MCTC). This technique allows larger blocks to be used when smaller blocks provide little gain, saving the bit rates, especially for areas containing more complex motion. However, the employment of the VBS motion estimation technique addresses a new optimization issue for the motion compensated coding (MCC), since an increased bit rate should be allocated to the VBS motion vectors. That is, the rate allocation between the motion vector encoding and the displaced frame difference (DFD) coding is an important issue. Hence, in this paper, a rate-distortion (R-D) optimization between the hierarchical VBS motion estimation and DFD coding is described. First, to make the R-D search feasible, the hierarchical VBS motion structures age grouped into two-level model structures and an efficient R-D search method is proposed. Next, a solution for the control of the VBS motion information, based on Lagrange multiplier method, is introduced. Intensive computer simulation employing the MCTC technique shows that an overall improvement up to 1.0 dB, compared to the fixed block size motion estimation, is obtained.

Kim, Jong-Won; Lee, Sang U.

1995-04-01

241

Earth Exploration Toolbook Chapter: Analyzing Plate Motion Using EarthScope GPS Data  

NSDL National Science Digital Library

DATA: EarthScope GPS Data. TOOLS: Spreadsheet, Google Maps. SUMMARY: Learn how GPS monuments make precise measurements of Earth's surface. Graph motion data and map velocity vectors to explore tectonic motion and surface deformation in the Pacific Northwest.

242

Use of Vestibular Models for Design and Evaluation of Flight Simulator Motion.  

National Technical Information Service (NTIS)

Quantitative models for the dynamics of the human vestibular system are applied to the design and evaluation of flight simulator platform motion. An optimal simulator motion control algorithm is generated to minimize the vector difference between perceive...

S. R. Bussolari L. R. Young A. T. Lee

1988-01-01

243

Clouds and Dust Storms  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 2 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

This image was acquired during mid-spring near the North Pole. The linear water-ice clouds are now regional in extent and often interact with neighboring cloud system, as seen in this image. The bottom of the image shows how the interaction can destroy the linear nature. While the surface is still visible through most of the clouds, there is evidence that dust is also starting to enter the atmosphere.

Image information: VIS instrument. Latitude 68.4, Longitude 180 East (180 West). 38 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2004-01-01

244

Diagnostics of vector magnetic fields  

NASA Technical Reports Server (NTRS)

It is shown that the vector magnetic fields derived from observations with a filter magnetograph will be severely distorted if the spatially unresolved magnetic structure is not properly accounted for. Thus the apparent vector field will appear much more horizontal than it really is, but this distortion is strongly dependent on the area factor and the temperature line weakenings. As the available fluxtube models are not sufficiently well determined, it is not possible to correct the filter magnetograph observations for these effects in a reliable way, although a crude correction is of course much better than no correction at all. The solution to this diagnostic problem is to observe simultaneously in suitable combinations of spectral lines, and/or use Stokes line profiles recorded with very high spectral resolution. The diagnostic power of using a Fourier transform spectrometer for polarimetry is shown and some results from I and V spectra are illustrated. The line asymmetries caused by mass motions inside the fluxtubes adds an extra complication to the diagnostic problem, in particular as there are indications that the motions are nonstationary in nature. The temperature structure appears to be a function of fluxtube diameter, as a clear difference between plage and network fluxtubes was revealed. The divergence of the magnetic field with height plays an essential role in the explanation of the Stokes V asymmetries (in combination with the mass motions). A self consistent treatment of the subarcsec field geometry may be required to allow an accurate derivation of the spatially averaged vector magnetic field from spectrally resolved data.

Stenflo, J. O.

1985-01-01

245

Iridescent Clouds  

Microsoft Academic Search

IN addition to the particulars given in NATURE for December 18, 1884 (p. 148) of the brilliantly-coloured clouds, the following observations made here may be interesting. They were visible every day from the 6th to the 13th instant, except it be on the 9th, and at all times of the day, but only strikingly noticeable near sunrise and sunset. The

T. W. Backhouse

1885-01-01

246

Deep Convective Clouds  

NSDL National Science Digital Library

Convective clouds are clouds that develop vertically appearing like big stacks of clouds. One very common example is cumulonimbus clouds. Convective clouds are commonly connected to stormy weather. Monthly Cloud Coverage for Deep Convective Cloud data can be used to predict patterns in weather. The specific pattern associated with this data is tracking and predicting thunderstorms. In this lesson, the students will take a look at the Monthly Cloud Coverage for Deep Convective Cloud data, and name one month of the year 'Thunderstorm Season' for their continent.

247

Guelph Physics Tutorials: Vectors  

NSDL National Science Digital Library

This page offers a straightforward tutorial on the fundamentals of vector operations. It is an illustrated guide to vector subtraction/addition, vector resolution, and multiplication of two vectors. It could serve as textbook supplementation or as content support for science teachers.

2008-08-15

248

Vector-Borne Diseases  

NSDL National Science Digital Library

This online encyclopedia article discusses vector-borne diseases. It defines vectors as the transmitters of disease-causing organisms that carry the pathogens from one host to another. The article reviews the biological range of vectors, the transmission and types of vector-borne diseases, patterns of occurrence and existing control measures.

Artsob, Harvey; Health, Encyclopedia O.

249

Estimating Cloud Cover  

ERIC Educational Resources Information Center

The purpose of this activity was to help students understand the percentage of cloud cover and make more accurate cloud cover observations. Students estimated the percentage of cloud cover represented by simulated clouds and assigned a cloud cover classification to those simulations. (Contains 2 notes and 3 tables.)

Moseley, Christine

2007-01-01

250

Brownian Motion  

NSDL National Science Digital Library

This simulation, part of the American Institute of Physics online exhibit on Einstein, shows the motion of a small particle due to bombardment by gas or liquid molecules. A trace of the path is also included, showing the famous "random walk."

2008-04-16

251

Brownian Motion.  

ERIC Educational Resources Information Center

Explains the phenomenon of Brownian motion, which serves as a mathematical model for random processes. Topics addressed include kinetic theory, Einstein's theory, particle displacement, and others. Points out that observations of the random course of a particle suspended in fluid led to the first accurate measurement of atomic mass. (DH)

Lavenda, Bernard H.

1985-01-01

252

Spring Motion  

NSDL National Science Digital Library

Created by Lang Moore and David Smith for the Connected Curriculum Project, the purposes of this module are to investigate a mathematical model for spring motion and to study the effect of increased damping. This is one within a much larger set of learning modules hosted by Duke University.

Moore, Lang; Smith, David

2010-06-09

253

Mondrian Motion  

Microsoft Academic Search

In this paper we develop a framework for motion estimation and stereo matching that allows explicit reasoning about occlusion relationships between untextured surface patches. We begin by studying a simplified problem, namely a Mondrian Worldthat consists of uniformly colored rectangles translating with constant velocities at different depths. We present methods for infer- ring the extent, velocity, and relative depth of

Timothy Bahls; Daniel Scharstein; Richard Szeliski

254

Projectile Motion  

NSDL National Science Digital Library

In this interactive simulation adapted from University of Colorado’s Physics Education Technology project, learn about projectile motion by firing various objects from a virtual cannon into the air. Experiment with the settings and try to hit a target.

Foundation, Wgbh E.

2007-04-19

255

Reliable camera motion estimation from compressed MPEG videos using machine learning approach  

NASA Astrophysics Data System (ADS)

As an important feature in characterizing video content, camera motion has been widely applied in various multimedia and computer vision applications. A novel method for fast and reliable estimation of camera motion from MPEG videos is proposed, using support vector machine for estimation in a regression model trained on a synthesized sequence. Experiments conducted on real sequences show that the proposed method yields much improved results in estimating camera motions while the difficulty in selecting valid macroblocks and motion vectors is skipped.

Wang, Zheng; Ren, Jinchang; Wang, Yubin; Sun, Meijun; Jiang, Jianmin

2013-05-01

256

Sast digital image stabilization using one bit transform based sub-image motion estimation  

Microsoft Academic Search

This paper presents a fast image sequence stabilization system that uses one bit transform (IBT) matching based global motion estimation and Kalman filtering based global motion correction. In order to facilitate a fast motion estimation process, image frames are initially converted into a single bit-plane representation using the IBT, and then motion vectors are evaluated matching the IBTs of two

A. Aysun Yeni; Sarp Ertürk

2005-01-01

257

A Novel Indexing Approach for Efficient and Fast Similarity Search of Captured Motions  

Microsoft Academic Search

Indexing of motion data is important for quickly searching similar motions for sign language recognition and gait analysis and reha- bilitation. This paper proposes a simple and ecien t tree structure for indexing motion data with dozens of attributes. Feature vectors are ex- tracted for indexing by using singular value decomposition (SVD) prop- erties of motion data matrices. By having

Chuanjun Li; B. Prabhakaran

2006-01-01

258

Vector Acoustics, Vector Sensors, and 3D Underwater Imaging  

NASA Astrophysics Data System (ADS)

Vector acoustic data has two more dimensions of information than pressure data and may allow for 3D underwater imaging with much less data than with hydrophone data. The vector acoustic sensors measures the particle motions due to passing sound waves and, in conjunction with a collocated hydrophone, the direction of travel of the sound waves. When using a controlled source with known source and sensor locations, the reflection points of the sound field can be determined with a simple trigonometric calculation. I demonstrate this concept with an experiment that used an accelerometer based vector acoustic sensor in a water tank with a short-pulse source and passive scattering targets. The sensor consists of a three-axis accelerometer and a matched hydrophone. The sound source was a standard transducer driven by a short 7 kHz pulse. The sensor was suspended in a fixed location and the hydrophone was moved about the tank by a robotic arm to insonify the tank from many locations. Several floats were placed in the tank as acoustic targets at diagonal ranges of approximately one meter. The accelerometer data show the direct source wave as well as the target scattered waves and reflections from the nearby water surface, tank bottom and sides. Without resorting to the usual methods of seismic imaging, which in this case is only two dimensional and relied entirely on the use of a synthetic source aperture, the two targets, the tank walls, the tank bottom, and the water surface were imaged. A directional ambiguity inherent to vector sensors is removed by using collocated hydrophone data. Although this experiment was in a very simple environment, it suggests that 3-D seismic surveys may be achieved with vector sensors using the same logistics as a 2-D survey that uses conventional hydrophones. This work was supported by the Office of Naval Research, program element 61153N.

Lindwall, D.

2007-12-01

259

The high-velocity clouds and the Magellanic Clouds  

NASA Astrophysics Data System (ADS)

From an analysis of the sky and velocity distributions of the high-velocity clouds (HVCs) we show that the majority of the HVCs has a common origin. We conclude that the HVCs surround the Galaxy, forming a metacloud of ˜ 300 kpc in size and with a mass of ˜ 3× 109 M?, and that they are the product of a powerful ``superwind'' (about 1058 ergs), which occurred in the Magellanic Clouds about 570 Myr ago as a consequence of the interaction of the Large and Small Magellanic Clouds. The HVCs might be magnetic bubbles of semi-ionized gas, blown from the Magellanic Clouds around 570 Myr ago, that circulate largely through the halo of the Galaxy as a stream or flow of gas. On the basis of the connection found between the HVCs and the Magellanic Clouds, we have constructed a theoretical model with the purpose of computing the orbits of a sample of test particles representing the HVCs, under the gravitational action of the Galaxy and the Magellanic Clouds. The orbits of the Large and Small Magellanic Clouds have been traced backwards in time to estimate the position and velocity of the Clouds at the time of the collision between the two Clouds, and to infer the initial conditions of the HVCs. The model can reproduce the main features of position and velocity distributions of the HVCs, like the overall structure and kinematics of the Magellanic Stream. The initial velocities of the HVCs were the result of velocities of expansion that permitted the escape of the HVCs from the Magellanic Clouds plus the systemic velocity of the Magellanic Clouds at the time of the collision. With these initial conditions, the Galactic gravitational potential induced differential rotations or shearing motions that elongated the cloud of HVCs in the orbital direction, forming the rear and front parts of the Magellanic stream. The population of HVCs is centered around the Magellanic Clouds. The eccentric position of the Sun within the cloud of HVCs explains the asymmetries between the sky distributions of the HVCs of the northern Galactic hemisphere and those of the southern Galactic hemisphere. In the light of the model we analyze the effects that the passage of the HVC flow through the Galactic disk has produced on the interstellar medium. The effects of the HVC flow can account for many observational details such as the Galactic warp, HI shells and supershells in the gaseous layer of the outer parts of the Milky Way. The Galactic disk was target of numerous impacts of HVCs in the course of the last 400 Myr, accumulating mass at the average rate of approximately 0.6 M? per year. The events of this period may be regarded as landmarks in the evolutionary history of the Milky Way.

Olano, C. A.

2004-09-01

260

Vectorization of Monte Carlo particle transport  

SciTech Connect

Fully vectorized versions of the Los Alamos National Laboratory benchmark code Gamteb, a Monte Carlo photon transport algorithm, were developed for the Cyber 205/ETA-10 and Cray X-MP/Y-MP architectures. Single-processor performance measurements of the vector and scalar implementations were modeled in a modified Amdahl's Law that accounts for additional data motion in the vector code. The performance and implementation strategy of the vector codes are related to architectural features of each machine. Speedups between fifteen and eighteen for Cyber 205/ETA-10 architectures, and about nine for CRAY X-MP/Y-MP architectures are observed. The best single processor execution time for the problem was 0.33 seconds on the ETA-10G, and 0.42 seconds on the CRAY Y-MP. 32 refs., 12 figs., 1 tab.

Burns, P.J.; Christon, M.; Schweitzer, R.; Lubeck, O.M.; Wasserman, H.J.; Simmons, M.L.; Pryor, D.V. (Colorado State Univ., Fort Collins, CO (USA). Computer Center; Los Alamos National Lab., NM (USA); Supercomputing Research Center, Bowie, MD (USA))

1989-01-01

261

Method and system for non-linear motion estimation  

NASA Technical Reports Server (NTRS)

A method and system for extrapolating and interpolating a visual signal including determining a first motion vector between a first pixel position in a first image to a second pixel position in a second image, determining a second motion vector between the second pixel position in the second image and a third pixel position in a third image, determining a third motion vector between one of the first pixel position in the first image and the second pixel position in the second image, and the second pixel position in the second image and the third pixel position in the third image using a non-linear model, determining a position of the fourth pixel in a fourth image based upon the third motion vector.

Lu, Ligang (Inventor)

2011-01-01

262

Types of Clouds  

NSDL National Science Digital Library

This is a basic lesson on clouds. Very nice photos of cumulus and cumulonimbus clouds are presented on the page as well as a description of all major cloud types and their associated weather. Two activities are presented. One invites the learner to create a cloud, while the other involves creating a collage of cloud images along with information about the weather associated with each cloud type.

Friend, Duane

263

Projectile Motion  

NSDL National Science Digital Library

Students are introduced to the concept of projectile motion, of which they are often familiar from life experiences,such as playing sports such as basketball or baseball, even though they may not understand the physics involved. Students use tabletop-sized robots to build projectile throwers and measure motion using sensors. They compute distances and velocities using simple kinematic equations and confirm their results through measurements by hand. To apply the concept, students calculate the necessary speed of an object to reach a certain distance in a hypothetical scenaro: A group of hikers stranded at the bottom of a cliff need food, but rescuers cannot deliver it themselves, so they must devise a way to get the food to the hikers.

Applying Mechatronics to Promote Science (AMPS) GK-12 Program,

264

Bad Clouds  

NSDL National Science Digital Library

This information is designed to belie the misconception that the capacity of air to hold water vapor is temperature dependent and that air can become saturated with water vapor. The temperature of a cloud droplet or ice crystal will be nearly the same as that of the air, so people imagine that somehow the air was to blame. But, if the other gases of the air were removed, leaving everything else the same, condensation and evaporation would proceed as before and the air was irrelevant to the behavior of the water molecules. It is therefore not correct to assign the behavior of water to an invented holding capacity of the air.

Fraser, Alistair

265

Orbital Motion  

NSDL National Science Digital Library

Authored by Eleanor Kopsian of Franklin Frazier, this is an activity intended to help students understand orbital motion and Kepler's Laws through a comparison of a circle and an ellipse and the application of Kepler's Law of Elliptical Orbits. The lesson contains objectives, vocabulary, needed materials, strategies, handouts, conclusions, evaluation questions and references. Although simple in design, this can still be a very useful resource for an instructor looking to enhance or create new curriculum.

Kopsian, Eleanor

2009-05-27

266

Cloud Infrastructure & Applications - CloudIA  

NASA Astrophysics Data System (ADS)

The idea behind Cloud Computing is to deliver Infrastructure-as-a-Services and Software-as-a-Service over the Internet on an easy pay-per-use business model. To harness the potentials of Cloud Computing for e-Learning and research purposes, and to small- and medium-sized enterprises, the Hochschule Furtwangen University establishes a new project, called Cloud Infrastructure & Applications (CloudIA). The CloudIA project is a market-oriented cloud infrastructure that leverages different virtualization technologies, by supporting Service-Level Agreements for various service offerings. This paper describes the CloudIA project in details and mentions our early experiences in building a private cloud using an existing infrastructure.

Sulistio, Anthony; Reich, Christoph; Doelitzscher, Frank

267

FIRE_AX_CMS_CLOUD  

FIRE_AX_CMS_CLOUD Project Title:  FIRE II ASTEX Discipline:  ... Order: ASDC Order Tool Parameters:  Cloud Amount Order Data:  ASDC Order Tool:  Order Data ... Sets Guide Readme Files:  Readme CMS_CLOUD (PS) CMS Cloud Info CMS Cloud Data ...

2014-05-06

268

Vector Addition Patterns Model  

NSDL National Science Digital Library

The Vector Addition Patterns model illustrates the tail-to-tip method of adding vectors. The table at the bottom shows the components and lengths of the vectors. You can also rotate the vectors and trace out some interesting patterns. The Vector Addition Patterns model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_addition_patterns.jar file will run the program if Java is installed.

Duffy, Andrew

2010-05-02

269

Reduced Vector Preisach Model  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

270

Vector-valued wavelets and vector filter banks  

Microsoft Academic Search

In this paper, we introduce vector-valued multiresolution analysis and vector-valued wavelets for vector-valued signal spaces. We construct vector-valued wavelets by using paraunitary vector filter bank theory. In particular, we construct vector-valued Meyer wavelets that are band-limited. We classify and construct vector-valued wavelets with sampling property. As an application of vector-valued wavelets, multiwavelets can be constructed from vector-valued wavelets. We show

Xiang-Gen Xia; B. W. Suter

1996-01-01

271

Ice Clouds in Martian Arctic (Accelerated Movie)  

NASA Technical Reports Server (NTRS)

Clouds scoot across the Martian sky in a movie clip consisting of 10 frames taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander.

This clip accelerates the motion. The camera took these 10 frames over a 10-minute period from 2:52 p.m. to 3:02 p.m. local solar time at the Phoenix site during Sol 94 (Aug. 29), the 94th Martian day since landing.

Particles of water-ice make up these clouds, like ice-crystal cirrus clouds on Earth. Ice hazes have been common at the Phoenix site in recent days.

The camera took these images as part of a campaign by the Phoenix team to see clouds and track winds. The view is toward slightly west of due south, so the clouds are moving westward or west-northwestward.

The clouds are a dramatic visualization of the Martian water cycle. The water vapor comes off the north pole during the peak of summer. The northern-Mars summer has just passed its peak water-vapor abundance at the Phoenix site. The atmospheric water is available to form into clouds, fog and frost, such as the lander has been observing recently.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

272

The Leo Cloud: Our Local Bubble Laboratory  

NASA Astrophysics Data System (ADS)

We present observations of an ultra-cold cloud of interstellar medium toward Leo. New large area, high resolution observations made with the Galactic Arecibo L-band Feed Array HI (GALFA-HI) Survey toward the Leo cloud have allowed us to inspect it with unprecedented sensitivity. Using stellar absorption results of sodium and calcium we can bracket the distance to this cloud to be further than 11 pc, but nearer than 45 pc, with a hint that it may also be in front of Regulus, at 24 pc. The vast extent of this cloud, at 15 degrees tip-to-tail, allows us to determine its 3-space motion using the perspective rotation method. We also present absorption line results to many background stars, which show an startlingly tight correlation between Leo cloud HI column and sodium column, perhaps indicating the Arecibo beam, about 4000 AU at this distance, is getting down to the scale at which the cloud is homogeneous. We also show clear soft X-ray shadowing results, which demonstrate that significant X-rays are generated both in front of and behind the Leo cloud.

Goldston Peek, Joshua; Heiles, C.; Peek, K. M. G.; Meyer, D.

2010-05-01

273

Estimating Conical Motion From Magnetometer Measurements  

NASA Technical Reports Server (NTRS)

Method of digital processing of outputs of magnetometer mounted on scientific instrument or other assembly provides estimates of parameters of slow oscillatory motion of assembly at constant or nearly constant frequency, in which motion one axis of assembly describes elliptical cone about nominal fixed or nearly fixed axis. Conceived for use in estimating rotational-and-vibrational motion of small instrumented satellite and 20-km-long tether anchored at lower end to Space Shuttle. Applicable to almost any situation in which assembly moves conically about known axis while measuring known vector.

Polites, M. E.

1993-01-01

274

Rotating Motion  

NSDL National Science Digital Library

In these problems, two people ride on a merry-go-round (radius fixed at 10 m..it's big!). One rider tosses a ball toward the other. The period of motion can be varied as can the initial velocity of the ball, relative to rider. One of the problems is to select the initial velocity of the ball so that it passes through center of the merry-go-round. Another is for the rider who throws the ball to catch it him/herself after exactly half a rotation.

Christian, Wolfgang; Belloni, Mario

2008-02-19

275

Understanding Singular Vectors  

ERIC Educational Resources Information Center

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

James, David; Botteron, Cynthia

2013-01-01

276

Raven—Vector Editing  

Microsoft Academic Search

\\u000a Raven is used to create fully scalable vector art appropriate for logos or t-shirt designs. Unlike the bitmaps you have used\\u000a in previous chapters, Raven uses vectors. A vector is an object defined by points in space, lines connecting those points together, and color that fills the shape in between\\u000a those lines. Vectors are defined mathematically and are drawn in

Mike Peutz

277

Investigation of water vapor motion winds from geostationary satellites  

NASA Technical Reports Server (NTRS)

Water vapor imagery from geostationary satellites has been available for over a decade. These data are used extensively by operational analysts and forecasters, mainly in a qualitative mode (Weldon and Holmes 1991). In addition to qualitative applications, motions deduced in animated water vapor imagery can be used to infer wind fields in cloudless regimes, thereby augmenting the information provided by cloud-drift wind vectors. Early attempts at quantifying the data by tracking features in water vapor imagery met with modest success (Stewart et al. 1985; Hayden and Stewart 1987). More recently, automated techniques have been developed and refined, and have resulted in upper-level wind observations comparable in quality to current operational cloud-tracked winds (Laurent 1993). In a recent study by Velden et al. (1993) it was demonstrated that wind sets derived from Meteosat-3 (M-3) water vapor imagery can provide important environmental wind information in data void areas surrounding tropical cyclones, and can positively impact objective track forecasts. M-3 was repositioned to 75W by the European Space Agency in 1992 in order to provide complete coverage of the Atlantic Ocean. Data from this satellite are being transmitted to the U.S. for operational use. Compared with the current GOES-7 (G-7) satellite (positioned near 112W), the M-3 water vapor channel contains a superior horizontal resolution (5 km vs. 16 km ). In this paper, we examine wind sets derived using automated procedures from both GOES-7 and Meteosat-3 full disk water vapor imagery in order to assess this data as a potentially important source of large-scale wind information. As part of a product demonstration wind sets were produced twice a day at CIMSS during a six-week period in March and April (1994). These data sets are assessed in terms of geographic coverage, statistical accuracy, and meteorological impact through preliminary results of numerical model forecast studies.

Velden, Christopher S.; Nieman, Steven J.; Wanzong, Steven

1994-01-01

278

Support vector domain description  

Microsoft Academic Search

This paper shows the use of a data domain description method, inspired by the support vector machine by Vapnik, called the support vector domain description (SVDD). This data description can be used for novelty or outlier de- tection. A spherically shaped decision boundary around a set of objects is constructed by a set of support vectors describing the sphere boundary.

David M. J. Tax; Robert P. W. Duin

1999-01-01

279

Visual simulation of clouds  

Microsoft Academic Search

Clouds present serious problems to standard computer image generation techniques because clouds do not have well-defined surfaces and boundaries. In addition, clouds contain varying degrees of translucence, and their amorphous structure can change with time. Although several approaches to cloud simulation have produced impressive results, they have relied on complex mathematical models which produce high computation costs for a single

Geoffrey Y. Gardner

1985-01-01

280

Stabilizing Motion Tracking Using Retrieved Motion Priors  

Microsoft Academic Search

In this paper, we introduce a novel iterative motion track- ing framework that combines 3D tracking techniques with motion retrieval for stabilizing markerless human motion capturing. The basic idea is to start human tracking without prior knowledge about the performed actions. The resulting 3D motion sequences, which may be corrupted due to track- ing errors, are locally classified according to

Andreas Baak; Bodo Rosenhahn; Meinard Müller; Hans-peter Seidel

2009-01-01

281

Clouds and climate change  

NASA Astrophysics Data System (ADS)

As concern grows over the possibility of altering the Earth's climate, a major uncertainty exists in computer models used to study the Earth's atmosphere, regarding our current understanding of clouds and our ability to simulate their effect on climate. A number of recent observations and computer simulation studies, however, have shed light on the important role of clouds in determining the present and future climate of our atmosphere.Data from the National Aeronautics and Space Administration's (NASA's) Earth Radiation Budget Experiment have been used to obtain an accurate picture of how clouds affect our present global climate system [Ramanathan, 1989]. The effect of clouds on solar and thermal radiation entering and leaving our climate is known as cloud forcing. Low clouds generally cool the Earth's surface, while high clouds warm the climate system. For the entire planet, however, the cooling effect of low clouds is stronger than the warming effect from high clouds, so that overall, clouds cool the climate.

Kiehl, Jeffrey T.

282

Multiple description motion coding algorithm for robust video transmission  

Microsoft Academic Search

This paper proposes a novel algorithm for robust transmission of video sequences, based on the multiple description motion coding (MDMC). In the MDMC, the motion vector field is encoded into two descriptions, which are transmitted over distinct channels to the decoder. The decoder is designed to provide an acceptable quality prediction image, even if one of the descriptions is lost

Chang-Su Kim; Sang-Uk Lee

2000-01-01

283

Recursive Estimation of Motion, Structure, and Focal Length  

Microsoft Academic Search

We present a formulation for recursive recoveryof motion, pointwise structure, and focal length from featurecorrespondences tracked through an image sequence.In addition to adding focal length to the state vector, severalrepresentational improvements are made over earlierstructure from motion formulations, yielding a stable andaccurate estimation framework which applies uniformly toboth true perspective and orthographic projection. Resultson synthetic and real imagery illustrate the...

Ali Azarbayejani; Alex P. Pentland

1995-01-01

284

A New Spatio-Temporal Fast Motion Estimation Algorithm  

Microsoft Academic Search

A new spatio-temporal approach is proposed for fast block motion estimation in video coding. The approach exploits the existing correlation of the spatio- temporal block neighborhood by utilizing the frequency of appearance of the neighborhood's motion vectors. Extensive simulations show that the proposed algorithm performs close to the full search algorithm (in terms of quality) with a significant computational gain.

V. Fotopoulos; A. N. Skodras

2007-01-01

285

Low-complexity motion estimation for VLBR video coders  

Microsoft Academic Search

A significant improvement of block-based motion estimation strategies is presented, which supports fast computation and VLBR coding. For each block, a spatio-temporal context is defined based on nearest neighbors in the current and previous frames, and a prediction list is built. Then, the best matching vector within the list is chosen as an estimation of the block motion. An additional

Francesco G. B. De Natale; Fabrizio Granelli; Gianni Vernazza

2002-01-01

286

Numerical modeling of altocumulus cloud layers  

NASA Astrophysics Data System (ADS)

Altocumulus (Ac) clouds are predominantly water clouds and typically less than several hundred meters thick. Ac cloud heights are mid-level, from 2 to 8 km. Ac clouds cover large portions of the Earth and play an important role in the Earth's energy budget through their effects on solar and infrared radiation. A two-dimensional cloud resolving model (CRM) and a one-dimensional turbulent closure model (TCM) are used to study Ac clouds with idealized initial conditions. An elevated mixed layer model (MLM) is developed and the results for the MLM are compared with results for CRM. The impacts of large-scale vertical motion, and solar and IR radiation, the utility of the TCM, the mixed layer characteristics and circulation of Ac layers, the turbulent kinetic energy (TKE) budget, and effects of relative humidify (RH) above the cloud are studied with a series of numerical simulations using the CRM and TCM. The results show that weak large-scale vertical motion may allow for a long lifetime of Ac clouds. In the nocturnal case, feedbacks between the liquid water path (LWP), IR radiation, and entrainment lead to an Ac layer with a nearly steady structure and circulation. The solar radiation in the diurnal case leads to decreases in the LWP, circulation intensity, and entrainment rate during the day. The comparison of TCM and CRM simulations suggests that TCM simulations can portray the basic characteristics of Ac clouds. The Ac convective layer includes mainly the cloud region and a shallow subcloud layer. In the Ac convective layers, the updrafts are wide and weak, whereas the downdrafts are narrow and strong. The updrafts are associated with regions of large cloud water mixing ratio, and the downdrafts with the regions of small cloud water mixing ratio. In Ac layers, the TKE is as large as in stratocumulus-topped-boundary-layer (STBL). The TKE is produced by buoyancy in the cloud region, dissipated by viscous dissipation, and redistributed upward and downward through turbulent transport. The Ac clouds become deeper when the RH above the cloud is high and can be maintained even if the RH above cloud is very low. The results and observations suggest that Ac layers are approximately well-mixed and similar to STBL. Therefore, an elevated MLM has been developed and tested for Ac layers. The Ac MLM uses a method for determining the entrainment rate at the mixed layer top that is used in many MLMs of the STBL. At the mixed layer base, the Ac mixed-layer model detrains at a rate that keeps the ratio of buoyant consumption of TKE in the subcloud layer to buoyant production in the cloud layer less than or equal to a critical value. The MLM results were good compared to the CRM results for cloud thickness, and fair for the LWP. The mixed layer magnitudes of conservative variables and flux profiles for the MLM agree reasonably to the results for the CRM.

Liu, Shuairen

1998-07-01

287

Cloud-Level Winds on Venus  

NASA Astrophysics Data System (ADS)

We have observed the nightside of Venus at 2.3 microns during a 10 day period with the IRTF on Mauna Kea. Each morning observation covered a 3-hour span, sufficient to determine the major cloud motions for each day. These observations have allowed us to construct movies of lower cloud motion, derive cloud-level winds, and identify transient features in the observed Venusian wind field. The lower cloud deck of Venus (48-52 km), is backlit by 2.3 micron thermal radiation emanating from about 35 km. We acquired both spectra and K-filter images centered at 2.26 microns with the SpeX instrument on the IRTF. By allowing the spectrometer slit to drift over the disk of Venus, we obtained spectral image cubes from 0.8 to 2.5 microns simultaneously with the images. By taking the sharpest 5% of those images in our data set we are typically able to achieve 0.5 arcsec resolution over the disk, or 220km resolution at the equator. In this talk we will present our processed images, cloud-motion movies, and derived wind speeds. Comparisons with previous ground-based (Crisp et al. 1991) and spacecraft (Carlson et al. 1991) datasets will be made, and the implications of our results for understanding the atmospheric circulation in Venus' lower cloud levels. This work was supported by NASA's Infrared Telescope Facility and by the NASA Planetary Astronomy Program. Carlson, R.W. et al., Science, 253, 1541-1548, 1991.; Crisp, D., et al., Science, 253, 1538-1541, 1991.

Tavenner, T.; Young, E. F.; Murphy, J.; Bullock, M. A.; Coyote, S.; Rafkin, S.

2005-08-01

288

The Oort cloud  

NASA Technical Reports Server (NTRS)

Views of the large-scale structure of the solar system, consisting of the Sun, the nine planets and their satellites, changed when Oort demonstrated that a gigantic cloud of comets (the Oort cloud) is located on the periphery of the solar system. The following subject areas are covered: (1) the Oort cloud's mass; (2) Hill's cloud mass; (3) angular momentum distribution in the solar system; and (4) the cometary cloud around other stars.

Marochnik, Leonid S.; Mukhin, Lev M.; Sagdeev, Roald Z.

1991-01-01

289

CERES CLoud Effects  

NSDL National Science Digital Library

This computer-generated animation depicts the Clouds and the Earth's Radiant Energy System (CERES) instrument in operation. CERES measures the energy at the top of the atmosphere and estimates energy levels in the atmosphere and at the Earth's surface. Using information from very high resolution cloud-imaging instruments on the same spacecraft, CERES also will determine cloud properties, including cloud amount, altitude, thickness, and the size of the cloud particles.

1997-06-06

290

Optimum instantaneous impulsive orbital injection to attain a specified asymptotic velocity vector.  

NASA Technical Reports Server (NTRS)

A nalysis of the necessary conditions of Battin for instantaneous orbital injection, with consideration of the uniqueness of his solution, and of the further problem which arises in the degenerate case when radius vector and asymptotic vector are separated by 180 deg. It is shown that when the angular separation between radius vector and asymptotic velocity vector satisfies theta not equal to 180 deg, there are precisely two insertion-velocity vectors which permit attainment of the target asymptotic velocity vector, one yielding posigrade, the other retrograde motion. When theta equals to 180 deg, there is a family of insertion-velocity vectors which permit attainment of a specified asymptotic velocity vector with a unique insertion-velocity vector for every arbitrary orientation of a target unit angular momentum vector.

Bean, W. C.

1971-01-01

291

SinoCor: motion correction in SPECT  

NASA Astrophysics Data System (ADS)

Motion is a serious artifact in Cardiac nuclear imaging because the scanning operation takes a long time. Since reconstruction algorithms assume consistent or stationary data the quality of resulting image is affected by motion, sometimes significantly. Even after adoption of the gold standard MoCo(R) algorithm from Cedars-Sinai by most vendors, heart motion remains a significant challenge. Also, any serious study in quantitative analysis necessitates correction for motion artifacts. It is generally recognized that human eye is a very sensitive tool for detecting motion. However, two reasons prevent such manual correction: (1) it is costly in terms of specialist's time, and (2) no such tool for manual correction is available currently. Previously, at SPIE-MIC'11, we presented a simple tool (SinoCor) that allows sinograms to be corrected manually or automatically. SinoCor performs correction of sinograms containing inter-frame patient or respiratory motions using rigid-body dynamics. The software is capable of detecting the patient motion and estimating the body-motion vector using scanning geometry parameters. SinoCor applies appropriate geometrical correction to all the frames subsequent to the frame when the movement has occurred in a manual or automated mode. For respiratory motion, it is capable of automatically smoothing small oscillatory (frame-wise local) movements. Lower order image moments are used to represent a frame and the required rigid body movement compensation is computed accordingly. Our current focus is on enhancement of SinoCor with the capability to automatically detect and compensate for intra-frame motion that causes motion blur on the respective frame. Intra-frame movements are expected in both patient and respiratory motions. For a controlled study we also have developed a motion simulator. A stable version of SinoCor is available under license from Lawrence Berkeley National Laboratory.

Mitra, Debasis; Eiland, Daniel; Abdallah, Mahmoud; Bouthcko, Rostyslav; Gullberg, Grant T.; Schechtmann, Norberto

2012-02-01

292

Plate Motions  

NSDL National Science Digital Library

To prepare for this exercise students read the Chapter on plate tectonics in their text book. In class, they are given a color isochron map of the sea floor. They are given 4 tasks: Answer basic questions about the timing and rate of opening of the N. and S. Atlantic; Determine what has happened to the oceanic crust that is created on the eastern side of the East Pacific Rise; Determine what type of plate boundary existed on the western edge of the N. America plate before the San Andreas Fault and when this transition occurred; and Reconstruct the motion of the plates over the last 40 Ma assuming that the surface area of the Earth has not changed.

Nunn, Jeffrey

293

Rotations with Rodrigues' vector  

NASA Astrophysics Data System (ADS)

The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

Piña, E.

2011-09-01

294

Cloud microphysical budget associated with torrential rainfall during the landfall of severe tropical storm Bilis (2006)  

NASA Astrophysics Data System (ADS)

Effects of vertical wind shear, radiation, and ice clouds on cloud microphysical budget associated with torrential rainfall during landfall of severe tropical storm Bilis (2006) are investigated by using a series of analysis of two-day grid-scale sensitivity experiment data. When upper-tropospheric upward motions and lower-tropospheric downward motions occur on 15 July 2006, the removal of vertical wind shear and ice clouds increases rainfall contributions from the rainfall type (CM) associated with positive net condensation and hydrometeor loss/convergence, whereas the exclusion of cloud radiative effects and cloud-radiation interaction reduces rainfall contribution from CM. The elimination of vertical wind shear and cloud-radiation interaction increases rainfall contribution from the rainfall type (Cm) associated with positive net condensation and hydrometeor gain/divergence, but the removal of cloud radiative effects and ice clouds decreases rainfall contribution from Cm. The enhancements in rainfall contribution from the rainfall type (cM) associated with negative net condensation and hydrometeor loss/convergence are caused by the exclusion of cloud radiative effects, cloud-radiation interaction and ice clouds, whereas the reduction in rainfall contribution from cM results from the removal of vertical wind shear. When upward motions appear throughout the troposphere on 16 July, the exclusion of all these effects increases rainfall contribution from CM, but generally decreases rainfall contributions from Cm and cM.

Wang, Donghai; Liu, Ying; Zhu, Ping; Yin, Jinfang; Li, Xiaofan; Tao, Wei-Kuo

2013-04-01

295

Gradient Vector Flow Fast Geometric Active Contours  

Microsoft Academic Search

Abstract—In this paper, we propose an edge-driven bidirectional geometric flow for boundary extraction. To this end, we combine the geodesic active contour flow [3] and the gradient vector flow external force for snakes,[25]. The resulting motion equation is considered within a level set formulation [19], can deal with topological changes,and important shape deformations. An efficient numerical,schema,is used for the flow

Nikos Paragios; Olivier Mellina-gottardo; Visvanathan Ramesh

2003-01-01

296

De gennes narrowing describes the relative motion of protein domains.  

PubMed

The relative motion of structural domains is essential for the biological function of many proteins. Here, by analyzing neutron scattering data and performing molecular dynamics simulations, we find that interdomain motion in several proteins obeys the principle of de Gennes narrowing, in which the wave vector dependence of the interdomain diffusion coefficient is inversely proportional to the interdomain structure factor. Thus, the rate of interdomain motion is inversely proportional to the probability distribution of the spatial configurations of domains. PMID:24785076

Hong, Liang; Smolin, Nikolai; Smith, Jeremy C

2014-04-18

297

de Gennes Narrowing Describes the Relative Motion of Protein Domains  

NASA Astrophysics Data System (ADS)

The relative motion of structural domains is essential for the biological function of many proteins. Here, by analyzing neutron scattering data and performing molecular dynamics simulations, we find that interdomain motion in several proteins obeys the principle of de Gennes narrowing, in which the wave vector dependence of the interdomain diffusion coefficient is inversely proportional to the interdomain structure factor. Thus, the rate of interdomain motion is inversely proportional to the probability distribution of the spatial configurations of domains.

Hong, Liang; Smolin, Nikolai; Smith, Jeremy C.

2014-04-01

298

The Essential Visibility Graph: An Approach to Global Motion Planning for Autonomous Mobile Robots  

Microsoft Academic Search

An approach to global motion planning for autonomous mobile robots has been developed on the basis of traversability vectors (t-vectors). Through the overall course of this research it was found that t-vectors provide a utility, efficiency and mathematical stability for collision detection and visibility that cannot be matched by commonly used algebraic approaches in static and dynamic environments. This paper

Jason A. Janét; Ren C. Luo; Michael G. Kay

1995-01-01

299

Role of Gravity Waves in Determining Cirrus Cloud Properties  

NASA Technical Reports Server (NTRS)

Cirrus clouds are important in the Earth's radiation budget. They typically exhibit variable physical properties within a given cloud system and from system to system. Ambient vertical motion is a key factor in determining the cloud properties in most cases. The obvious exception is convectively generated cirrus (anvils), but even in this case, the subsequent cloud evolution is strongly influenced by the ambient vertical motion field. It is well know that gravity waves are ubiquitous in the atmosphere and occur over a wide range of scales and amplitudes. Moreover, researchers have found that inclusion of statistical account of gravity wave effects can markedly improve the realism of simulations of persisting large-scale cirrus cloud features. Here, we use a 1 -dimensional (z) cirrus cloud model, to systematically examine the effects of gravity waves on cirrus cloud properties. The model includes a detailed representation of cloud microphysical processes (bin microphysics and aerosols) and is run at relatively fine vertical resolution so as to adequately resolve nucleation events, and over an extended time span so as to incorporate the passage of multiple gravity waves. The prescribed gravity waves "propagate" at 15 m s (sup -1), with wavelengths from 5 to 100 km, amplitudes range up to 1 m s (sup -1)'. Despite the fact that the net gravity wave vertical motion forcing is zero, it will be shown that the bulk cloud properties, e.g., vertically-integrated ice water path, can differ quite significantly from simulations without gravity waves and that the effects do depend on the wave characteristics. We conclude that account of gravity wave effects is important if large-scale models are to generate realistic cirrus cloud property climatology (statistics).

OCStarr, David; Singleton, Tamara; Lin, Ruei-Fong

2008-01-01

300

Index Sets and Vectorization  

SciTech Connect

Vectorization is data parallelism (SIMD, SIMT, etc.) - extension of ISA enabling the same instruction to be performed on multiple data items simultaeously. Many/most CPUs support vectorization in some form. Vectorization is difficult to enable, but can yield large efficiency gains. Extra programmer effort is required because: (1) not all algorithms can be vectorized (regular algorithm structure and fine-grain parallelism must be used); (2) most CPUs have data alignment restrictions for load/store operations (obey or risk incorrect code); (3) special directives are often needed to enable vectorization; and (4) vector instructions are architecture-specific. Vectorization is the best way to optimize for power and performance due to reduced clock cycles. When data is organized properly, a vector load instruction (i.e. movaps) can replace 'normal' load instructions (i.e. movsd). Vector operations can potentially have a smaller footprint in the instruction cache when fewer instructions need to be executed. Hybrid index sets insulate users from architecture specific details. We have applied hybrid index sets to achieve optimal vectorization. We can extend this concept to handle other programming models.

Keasler, J A

2012-03-27

301

Airborne observations of electric fields around growing and decaying cumulus clouds  

NASA Technical Reports Server (NTRS)

Airborne electric field data were gathered in an atmospheric electrification study near Cape Canaveral, FL. A Learjet 36A was instrumented with eight electric field meters (mills) and five different particle probes. The local electric field enhancements at each field mill site were determined under lab conditions and verified using in-flight data. The overdetermined system of eight equations (one for each field mill) was solved using a weighted least squares algorithm to compute the magnitude and direction of the ambient electric field. The signal processing system allowed the measured data to be expressed in terms of earth coordinates, regardless of the attitude of the aircraft. Thus, it was possible to take maximum advantage of the Learjet's speed and maneuverability in studying the electric field structure in the vicinity of the clouds. Data gathered while circling just outside the boundary of a growing cumulus cloud show a nonsymmetric pattern of electric field strength. Field intensity grew rapidly over a period of less than 10 minutes. The observed direction of the ambient electric field vector can be explained by an ascending motion of the charge centers of a classic tripole model of a thunderstorm.

Giori, K. L.; Nanevicz, J. E.

1991-01-01

302

Limits to Cloud Susceptibility  

NASA Technical Reports Server (NTRS)

1-kilometer AVHRR observations of ship tracks in low-level clouds off the west coast of the U S. were used to determine limits for the degree to which clouds might be altered by increases in anthropogenic aerosols. Hundreds of tracks were analyzed to determine whether the changes in droplet radii, visible optical depths, and cloud top altitudes that result from the influx of particles from underlying ships were consistent with expectations based on simple models for the indirect effect of aerosols. The models predict substantial increases in sunlight reflected by polluted clouds due to the increases in droplet numbers and cloud liquid water that result from the elevated particle concentrations. Contrary to the model predictions, the analysis of ship tracks revealed a 15-20% reduction in liquid water for the polluted clouds. Studies performed with a large-eddy cloud simulation model suggested that the shortfall in cloud liquid water found in the satellite observations might be attributed to the restriction that the 1-kilometer pixels be completely covered by either polluted or unpolluted cloud. The simulation model revealed that a substantial fraction of the indirect effect is caused by a horizontal redistribution of cloud water in the polluted clouds. Cloud-free gaps in polluted clouds fill in with cloud water while the cloud-free gaps in the surrounding unpolluted clouds remain cloud-free. By limiting the analysis to only overcast pixels, the current study failed to account for the gap-filling predicted by the simulation model. This finding and an analysis of the spatial variability of marine stratus suggest new ways to analyze ship tracks to determine the limit to which particle pollution will alter the amount of sunlight reflected by clouds.

Coakley, James A., Jr.

2002-01-01

303

Motion Estimation for Frame-Rate Reduction in H.264 Transcoding  

Microsoft Academic Search

This paper proposes a transcoding method for frame rate reduction in H.264 video coding standard. H.264 adopts various block types and multiple reference frames for motion compensation. When frames are skipped to reduce frame rates in transcoder, it is not easy to estimate optimum motion vectors and block types in H.264. A simple and effective block-adaptive motion vector resampling (BAMVR)

Il-hong Shin; Yung-Lyul Lee; Hyun Wook Park

2004-01-01

304

Descriptor for spatial distribution of motion activity for compressed video  

NASA Astrophysics Data System (ADS)

In this paper we present a new descriptor for spatial distribution of motion activity in video sequences. We use the magnitude of the motion vectors as a measure of the intensity of motion cavity in a macro-block. We construct a matrix Cmv consisting of the magnitudes of the motion vector for each macro-block of a given P frame. We compute the average magnitude of the motion vector per macro-block Cavg, and then use Cavg as a threshold on the matrix C by setting the elements of C that are less than Cavg to zero. We classify the runs of zeros into three categories based on length, and count the number of runs of each category in the matrix C. Our activity descriptor for a frame thus consists of four parameters viz. the average magnitude of the motion vectors and the numbers of runs of short, medium and long length. Since the feature extraction is in the compressed domain and simple, it is extremely fast. We have tested it on the MPEG-7 test content set, which consists of approximately 14 hours of MPEG-1 encoded video content of different kinds. We find that our descriptor enables fast and accurate indexing of video. It is robust to noise and changes in encoding parameters such as frame size, frame rate, encoding bit rate, encoding format etc. It is a low-level non-semantic descriptor that gives semantic matches within the same program, and is thus very suitable for applications such as video program browsing. We also find that indirect and computationally simpler measures of the magnitude of the motion vectors such as bits taken to encode the motion vectors, though less effective, also can be used in our run-length framework.

Divakaran, Ajay; Sun, Huifang

1999-12-01

305

The interstellar cloud surrounding the Sun: a new perspective  

NASA Astrophysics Data System (ADS)

Aims: We offer a new, simpler picture of the local interstellar medium, made of a single continuous cloud enveloping the Sun. This new outlook enables the description of a diffuse cloud from within and brings to light some unexpected properties. Methods: We re-examine the kinematics and abundances of the local interstellar gas, as revealed by the published results for the ultraviolet absorption lines of Mg II, Fe II, and H I. Results: In contrast to previous representations, our new picture of the local interstellar medium consists of a single, monolithic cloud that surrounds the Sun in all directions and accounts for most of the matter present in the first 50 parsecs around the Sun. The cloud fills the space around us out to about 9 pc in most directions, although its boundary is very irregular with possibly a few extensions up to 20 pc. The cloud does not behave like a rigid body: gas within the cloud is being differentially decelerated in the direction of motion, and the cloud is expanding in directions perpendicular to this flow, much like a squashed balloon. Average H I volume densities inside the cloud vary between 0.03 and 0.1 cm-3 over different directions. Metals appear to be significantly depleted onto grains, and there is a steady increase in depletion from the rear of the cloud to the apex of motion. There is no evidence that changes in the ionizing radiation influence the apparent abundances. Secondary absorption components are detected in 60% of the sight lines. Almost all of them appear to be interior to the volume occupied by the main cloud. Half of the sight lines exhibit a secondary component moving at about -7.2 km s-1 with respect to the main component, which may be the signature of a shock propagating toward the cloud's interior.

Gry, Cécile; Jenkins, Edward B.

2014-07-01

306

'Striated Delta' Clouds As Tracers Of Inertia-Gravity Wave Emission From Upper Jets And Extratropical Cyclones  

NASA Astrophysics Data System (ADS)

'Striated Delta' cloud formations are frequently tracers of upper-tropospheric inertia-gravity wave disturbances near the jet stream, coincident with rapid extratropical cyclogenesis (Feren, 1995). The investigation of source mechanisms in this context is important for better understanding of how and where large-amplitude inertia-gravity waves are generated, which propagate energy throughout the atmosphere and transfer it to the mean flow through breaking or attenuation processes. A seasonal study of twenty-eight Striated Delta events in the Australia/New Zealand region during May to September 2009 is analysed in the high-resolution ECMWF YOTC dataset. Mean composite analyses show that Striated Deltas occur in an upper-tropospheric environment of strong horizontal divergence, strong parcel accelerations, strong vertical motion and geostrophic imbalance. Synoptically, the Striated Delta cases occur in the poleward jet exit region near the axis of inflexion between an upstream upper trough and a downstream upper ridge. This is consistent with findings of previous studies regarding the synoptic environment characteristic of gravity wave generation. A Q-vector partitioning analysis suggests that flow curvature and advection of shear are the two greatest components to synoptic scale vertical motion forcing. The Q-Vector analysis also explains the characteristic triangular shape of the Striated Delta cloud formation. It is hypothesised that strong parcel accelerations due to curvature of the flow, as well as air parcel deceleration in the jet streak exit region, are responsible for the generation of inertia-gravity waves evident in the banding of Striated Delta clouds. Furthermore, deep convection is favoured in the poleward jet exit region by the ageostrophic circulation and is also thought to play a role in the generation of waves and the modulation of wavelengths. A distinct and interesting Striated Delta and extratropical cyclogenesis event from September 2009 is simulated in high-resolution in the Weather Research and Forecasting (WRF) Model, and the wave source dynamics investigated further. Feren, G., 1995: The "Striated Delta" Cloud System - A satellite imagery precursor to major cyclogenesis in the Eastern Australian-Western Tasman Sea region. Wea. Forecasting, 10, 286-309.

Morgan, A. L.; Reeder, M. J.

2012-12-01

307

Flexi vector cloning.  

PubMed

A protocol for ligation-dependent cloning using the Flexi Vector method in a 96-well format is described. The complete protocol includes PCR amplification of the desired gene to append Flexi Vector cloning sequences, restriction digestion of the PCR products, ligation of the digested PCR products into a similarly digested acceptor vector, transformation and growth of host cells, analysis of the transformed clones, and storage of a sequence-verified clone. The protocol also includes transfer of the sequence-verified clones into another Flexi Vector plasmid backbone. Smaller numbers of cloning reactions can be undertaken by appropriate scaling of the indicated reaction volumes. PMID:18988018

Blommel, Paul G; Martin, Peter A; Seder, Kory D; Wrobel, Russell L; Fox, Brian G

2009-01-01

308

Society for Vector Ecology  

NSDL National Science Digital Library

Formed in 1968, the Society for Vector Ecology (SOVE) is dedicated to studying "all aspects of the biology, ecology, and control of arthropod vectors and the interrelationships between the vectors and the disease agents they transmit." Comprised of researchers and operational and extension personnel around the globe, SOVE tracks and studies the biological organisms that transmit diseases. The SOVE Website contains information related to the Society (e.g., mission, history), its publications (journal, newsletter -- both .pdf format), and professional opportunities (conferences, employment). Several dozen links to additional vector ecology resources are provided.

2008-09-12

309

Streaming instabilities in multicomponent interstellar clouds  

SciTech Connect

Streaming instabilities in interstellar clouds have been investigated. It is pointed out that the motion of a lighter dust species relative to a plasma containing a heavier dust species can give rise to low frequency electrostatic fluctuations. The dust ion acoustic and dust acoustic waves can become unstable in such plasmas. The instability regions are influenced by the presence of background dust. Since interstellar clouds have relative motions in many cases and contain dust species, therefore the present results indicate the presence of an electrostatic dust ion acoustic wave and dust acoustic wave in such systems. The results have been applied to interstellar medium using particular data and comparisons have been made with previous works.

Shan, S. Ali; Sajid, M. [Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Saleem, H. [Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); National Centre for Physics (NCP), Quaid-i-Azam University, Islamabad (Pakistan)

2008-07-15

310

Aircraft penetrations of arc cloud lines  

NASA Technical Reports Server (NTRS)

Results of a NOAA/NASA research field program (1982-1983) which focused on dynamic and thermodynamic characterization of arc cloud lines are discussed. The program combines research aircraft flights with rapid-scan (3-minute interval) GOES imagery and covers the subcloud layer above and below the density surge line. Strong differences in the dynamic characteristics of air are noted to exist within and above the density surge line (DSL); air motions within the DSL are much more turbulent, with stronger upward and downward motions, than in the subcloud layer above the DSL. The arc cloud lines and the associated DSL regions are concluded to pose an extreme potential hazard to aircraft and Space Shuttle operations.

Sinclair, P. C.; Purdom, J. F. W.

1984-01-01

311

Dual-FOV Raman and Doppler lidar studies of aerosol-cloud interactions: Simultaneous profiling of aerosols, warm-cloud properties, and vertical wind  

NASA Astrophysics Data System (ADS)

For the first time, colocated dual-field of view (dual-FOV) Raman lidar and Doppler lidar observations (case studies) of aerosol and cloud optical and microphysical properties below and within thin layered liquid water clouds are presented together with an updraft and downdraft characterization at cloud base. The goal of this work is to investigate the relationship between aerosol load close to cloud base and cloud characteristics of warm (purely liquid) clouds and the study of the influence of vertical motions and turbulent mixing on this relationship. We further use this opportunity to illustrate the applicability of the novel dual-FOV Raman lidar in this field of research. The dual-FOV lidar combines the well-established multiwavelength Raman lidar technique for aerosol retrievals and the multiple-scattering Raman lidar technique for profiling of the single-scattering extinction coefficient, effective radius, number concentration of the cloud droplets, and liquid water content. Key findings of our 3 year observations are presented in several case studies of optically thin altocumulus layers occurring in the lower free troposphere between 2.5 and 4 km height over Leipzig, Germany, during clean and polluted situations. For the clouds that we observed, the most direct link between aerosol proxy (particle extinction coefficient) and cloud proxy (cloud droplet number concentration) was found at cloud base during updraft periods. Above cloud base, additional processes resulting from turbulent mixing and entrainment of dry air make it difficult to determine the direct impact of aerosols on cloud processes.

Schmidt, Jörg; Ansmann, Albert; Bühl, Johannes; Baars, Holger; Wandinger, Ulla; Müller, Detlef; Malinka, Aleksey V.

2014-05-01

312

PhET Teacher Activities: Vectors Simulations Lab  

NSDL National Science Digital Library

This virtual lab was developed by a high school teacher specifically for use with the PhET simulation "Motion in 2D". It provides explicit direction for using the simulation to explore vector quantities, vector addition, and calculating resultants. In the last half of the activity, students demonstrate understanding by performing specific calculations, then using the simulation to check their work. The lesson includes printable student data tables. The associated simulation (which must be running to complete this activity) is available from PhET at: Motion in 2D.

Bires, Chris

2013-02-05

313

Hierarchical image sequence coding with tree-structured vector quantization  

NASA Astrophysics Data System (ADS)

The paper presents two different approaches to image sequence coding which exploit the spatial frequency statistics as well as the spatial and temporal correlation present in the video signal. The first approach is the pyramidal decomposition of the Motion Compensated Frame Difference (MCFD) signal in the frequency domain and the subsequent coding by unbalanced Tree Structured Vector Quantizers (TSVQ) designed to match the statistics of the frequency bands. The type of TSVQ used in this study possess the advantage of low computational complexity with coding performance comparable to full-search vector quantization. The second approach is similar except that the order of motion estimation/compensation and pyramidal decomposition are interchanged.

Bayazit, Ulug; Pearlman, William A.

1993-10-01

314

An Adaptive Block Size Phase Correlation Motion Estimation using Smart Multireference Frames Selection in Frequency Domain  

Microsoft Academic Search

The multiple reference frame motion compensation (MRMC) supported by H.264 makes use of redundancy between multiple frames to enhance the coding efficiency over the techniques which use a single reference frame motion compensation. However, searching the motion vectors in multiple frames is computationally expensive. This paper proposes a smart MRMC selection technique, which has a lower search complexity without sacrificing

Yasser Ismail; M. Elgamel; J. L. Tecpanecatl-Xihuitl; M. Bayoumi

2007-01-01

315

EFFECT OF SPATIAL VARIABILITY OF GROUND MOTION ON BRIDGE FRAGILITY CURVES  

Microsoft Academic Search

This paper examines the impact of stochastic spatial variability of seismic ground motion on the seismic response of long, multi-span, reinforced concrete bridges. The spatially varying ground motion time histories at the structural supports are generated using a variation of the spectral representation method that considers ground motion to be a stochastic vector process. According to this methodology, acceleration time

Masanobu Shinozuka

316

PSC Meteorology Program Cloud Boutique  

NSDL National Science Digital Library

Plymouth State College (PSC) provides the PSC Meteorology Program Cloud Boutique Website to "provide explanations of and access to detailed pictures of some basic cloud forms." Spectacular images and brief descriptions of high clouds (cirrus, cirrocumulus, and cirrostratus), middle clouds (altocumulus and altostratus), low clouds (cumulus, stratocumulus, stratus, and fog), multi-layer clouds (nimbostratus and cumulonimbus), and orographic clouds (lenticular and cap), among others are included. The site is an excellent general cloud reference.

317

High velocity clouds in nearby disk galaxies  

NASA Technical Reports Server (NTRS)

Clouds of neutral hydrogen in our galaxy with the absolute value of v greater than 100 km/s cover approximately 10 percent of the sky to a limiting column density of 1 x 10(exp 18) cm(exp -2). These high velocity clouds (HVCs) may dominate the kinetic energy of neutral hydrogen in non-circular motion, and are an important though poorly understood component of galactic gas. It has been suggested that the HVCs can be reproduced by a combination of three phenomena: a galactic fountain driven by disk supernovae which would account for most of the HVCs, material tidally torn from the Magellanic Clouds, and an outer arm complex which is associated with the large scale structure of the warped galactic disk. We sought to detect HVCs in external galaxies in order to test the galactic fountain model.

Schulman, Eric; Bregman, Joel N.; Roberts, Morton S.; Brinks, Elias

1993-01-01

318

Limited range of motion  

MedlinePLUS

Limited range of motion is a term meaning that a joint or body part cannot move through its normal range of motion. ... Motion may be limited because of a problem within the joint, swelling of tissue around the joint, ...

319

Cloud Computing for radiologists.  

PubMed

Cloud computing is a concept wherein a computer grid is created using the Internet with the sole purpose of utilizing shared resources such as computer software, hardware, on a pay-per-use model. Using Cloud computing, radiology users can efficiently manage multimodality imaging units by using the latest software and hardware without paying huge upfront costs. Cloud computing systems usually work on public, private, hybrid, or community models. Using the various components of a Cloud, such as applications, client, infrastructure, storage, services, and processing power, Cloud computing can help imaging units rapidly scale and descale operations and avoid huge spending on maintenance of costly applications and storage. Cloud computing allows flexibility in imaging. It sets free radiology from the confines of a hospital and creates a virtual mobile office. The downsides to Cloud computing involve security and privacy issues which need to be addressed to ensure the success of Cloud computing in the future. PMID:23599560

Kharat, Amit T; Safvi, Amjad; Thind, Ss; Singh, Amarjit

2012-07-01

320

Self Motion Perception and Motion Sickness  

NASA Technical Reports Server (NTRS)

The studies conducted in this research project examined several aspects of motion sickness in animal models. A principle objective of these studies was to investigate the neuroanatomy that is important in motion sickness with the objectives of examining both the utility of putative models and defining neural mechanisms that are important in motion sickness.

Fox, Robert A. (Principal Investigator)

1991-01-01

321

"Electrostructural Phase Changes" In Charged Particulate Clouds: Planetary and Astrophysical Implications  

NASA Astrophysics Data System (ADS)

There is empirical evidence that freely-suspended triboelectrostatically charged particulate clouds of dielectric materials undergo rapid conversion from (nominally) monodispersed "aerosols" to a system of well-defined grain aggregates after grain motion or fluid turbulence ceases within the cloud. In United States Microgravity Laboratory Space Shuttle experiments USML-1 and USML-2, it was found that ballistically-energized grain dispersions would rapidly convert into populations of filamentary aggregates after natural fluid (air) damping of grain motion. Unless continuously disrupted mechanically, it was impossible to maintain a non-aggregated state for the grain clouds of sand-size materials. Similarly, ground- based experiments with very fine dust-size material produced the same results: rapid, impulsive "collapse" of the dispersed grains into well-defined filamentary structures. In both ground-based and microgravity experiments, the chains or filaments were created by long-range dipole electrostatic forces and dipole-induced dielectric interactions, not by monopole interactions. Maintenance of the structures was assisted by short-range static boundary adhesion forces and van der Waals interactions. When the aggregate containers in the USML experiments were disturbed after aggregate formation, the quiescently disposed filaments would rearrange themselves into fractal bundles and tighter clusters as a result of enforced encounters with one another. The long-range dipole interactions that bring the grains together into aggregates are a product of randomly-distributed monopole charges on the grain surfaces. In computer simulations, it has been shown that when the force vectors of all the random charges (of both sign) on a grain are resolved mathematically by assuming Coulombic interaction between them, the net result is a dipole moment on individual grains, even though the grains are electrically neutral insofar as there is no predominance, on their surface, of one charge sign over another. The random charges of both sign derive from natural grain-to-grain interactions that produce triboelectrification via charge exchange every time grain surfaces make contact with one another. The conversion from a random distribution of grains (upon which there are randomly distributed charges) into an organization of electrostatically-ordered aggregates, can be regarded (within the framework of granular-material science) as an "electrical or Coulombic phase change" of the particulate cloud. It is not totally dissimilar from the more normal phase-change concept in which, for example, a gas with long free-path-molecules suddenly becomes a solid as a result of structural ordering of the molecules (notably, also the result of electronic forces, albeit at a different scale). In both the gas-to-solid case, and the aerosol-to-aggregate case, the same materials and charges are present before and after the phase change, but their arrangement now has a higher degree of order and a lower-energy configuration. An input of energy into the system is required to reverse the situation. The aggregates in the USML experiments were observed to undergo at least two phase changes as noted above. The point about phase changes, and by implication, the "electrostructural" reorganizations in particulate clouds, is the following: (a) they can occur very rapidly, almost spontaneously, above a critical cloud density, (b) in going from a higher energy state to a lower energy state, they convert to a denser system, (c) energy must be required to reverse the situation, implying that energy is released during the high-to-low energy phase change. In applying this information to natural particulate clouds, some inferences can be made (it is stressed that reference is still to dielectric materials attracted by dipole forces). There are several natural settings to which the USML observations apply, and to which the phase-change implications likewise apply. Dense clouds of triboelectrically-charged, kinetically-energized grains are

Marshall, J. R.

1999-09-01

322

Diagnosing the severe thunderstorm environment by mesoscale cloud tracking - A new approach and new information  

NASA Technical Reports Server (NTRS)

A new method for cloud tracking and observing storm development using satellite imagery in a cloud relative mode is presented. This method changes the analyst's function to one of monitoring cloud growth and changes over a finite time period and identifying portions of the cloud that are suitable for use as trackers. It is shown how many problems previously encountered by meteorologists in mesoscale cloud tracking can be overcome by using the cloud relative technique to determine mesoscale flow fields whose heights are determined using stereographic techniques. By separating growth and decay from cloud motion in a cumulus field using the method and accurately defining cloud heights, vertical wind shears within mesoscale domains may be defined. When this information is used to study the relative velocity of flows at different levels with respect to a developing or mature storm, improved insight into storm behavior can be achieved.

Purdom, J. F. W.; Vonder Haar, T. H.; Stewart, J. K.; Leary, N. E.

1984-01-01

323

Personal Cloud Computing Security Framework  

Microsoft Academic Search

Cloud computing is an evolving term these days. It describes the advance of many existing IT technologies and separates application and information resources from the underlying infrastructure. Personal Cloud is the hybrid deployment model that is combined private cloud and public cloud. By and large, cloud orchestration does not exist today. Current cloud service is provided by web browser or

Sang-Ho Na; Jun-Young Park; Eui-nam Huh

2010-01-01

324

Head in the Clouds  

NSDL National Science Digital Library

In this activity, learners create a CloudSpotter wheel and record the different types of clouds they observe twice daily over several days. Use this activity to teach learners how to identify different types of clouds as well as improve their observation skills. If possible, plan this lesson within four days of an upcoming cold front. This will help maximize the variety of clouds the learners will observe. This resource also includes tips about foggy weather safety.

Service, National W.

2013-04-10

325

Stability of Horndeski vector-tensor interactions  

NASA Astrophysics Data System (ADS)

We study the Horndeski vector-tensor theory that leads to second order equations of motion and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably simple and consists of only 2 terms for the vector field, namely: the standard Maxwell kinetic term and a coupling to the dual Riemann tensor. Furthermore, the vector sector respects the U(1) gauge symmetry and the theory contains only one free parameter, M2, that controls the strength of the non-minimal coupling. We explore the theory in a de Sitter spacetime and study the presence of instabilities and show that it corresponds to an attractor solution in the presence of the vector field. We also investigate the cosmological evolution and stability of perturbations in a general FLRW spacetime. We find that a sufficient condition for the absence of ghosts is M2 > 0. Moreover, we study further constraints coming from imposing the absence of Laplacian instabilities. Finally, we study the stability of the theory in static and spherically symmetric backgrounds (in particular, Schwarzschild and Reissner-Nordström-de Sitter). We find that the theory, quite generally, do have ghosts or Laplacian instabilities in regions of spacetime where the non-minimal interaction dominates over the Maxwell term. We also calculate the propagation speed in these spacetimes and show that superluminality is a quite generic phenomenon in this theory.

Beltrán Jiménez, Jose; Durrer, Ruth; Heisenberg, Lavinia; Thorsrud, Mikjel

2013-10-01

326

Optical currents in coherent and partially coherent vector fields  

NASA Astrophysics Data System (ADS)

We present the results of computer simulation of spatial distribution of the Poynting vector and illustrate motion of microparticles in spatially inhomogeneously polarized fields. The influence of phase relations and the degree of mutual coherence of superposing waves in the arrangements of two-wave and four-wave superposition on the characteristics of microparicle's motion has been analyzed. The prognosis of prospects of the study of temporal coherence using the proposed approach is made.

Angelsky, O. V.; Maksimyak, P. P.; Zenkova, C. Yu.; Gorsky, M. P.; Gorodynska, N. V.

2010-09-01

327

LCD motion blur reduction: a signal processing approach.  

PubMed

Liquid crystal displays (LCDs) have shown great promise in the consumer market for their use as both computer and television displays. Despite their many advantages, the inherent sample-and-hold nature of LCD image formation results in a phenomenon known as motion blur. In this work, we develop a method for motion blur reduction using the Richardson-Lucy deconvolution algorithm in concert with motion vector information from the scene. We further refine our approach by introducing a perceptual significance metric that allows us to weight the amount of processing performed on different regions in the image. In addition, we analyze the role of motion vector errors in the quality of our resulting image. Perceptual tests indicate that our algorithm reduces the amount of perceivable motion blur in LCDs. PMID:18270104

Har-Noy, Shay; Nguyen, Truong Q

2008-02-01

328

Hyperphysics: The Cloud Chamber  

NSDL National Science Digital Library

This Hyperphysics webpage contains a short description of the Wilson cloud chamber and two photographs by Wilson himself of cloud chamber tracks. Links provides information about various methods of detecting radiation and also about the muon, an elementary particle that was first detected in a cloud chamber. The text on this page is written at a level of a student of introductory physics.

Nave, Carl R.

2008-11-26

329

Bad Meteorology: Bad Clouds  

NSDL National Science Digital Library

This site provides an explanation for cloud formation and seeks to correct myths or misconceptions about how clouds form. Water vapor, condensation, and evaporation are discussed in the context of dew-point temperature and saturation. Educators and anyone explaining cloud formation will find hints on how to present the correct information and avoid misinforming their audiences.

Fraser, Alistair

330

Point Cloud Collision Detection  

Microsoft Academic Search

In the past few years, many efficient rendering and surface reconstruction algorithms for point clouds have been de- veloped. However, collision detection of point clouds has not been considered until now, although this is a prerequisite to use them for interactive or animated 3D graphics. We present a novel approach for time-critical collision detection of point clouds. Based solely on

Jan Klein; Gabriel Zachmann

2004-01-01

331

Clouds in Planetary Atmospheres  

NASA Technical Reports Server (NTRS)

In the terrestrial atmosphere clouds are familiar as vast collections of small water drops or ice cyrstals suspended in the air. The study of clouds touches on many facets of armospheric science. The chemistry of clouds is tied to the chemistry of the surrounding atmosphere.

West, R.

1999-01-01

332

Complex Vector Formalism of Harmonic Oscillator in Geometric Algebra: Particle Mass, Spin and Dynamics in Complex Vector Space  

NASA Astrophysics Data System (ADS)

Elementary particles are considered as local oscillators under the influence of zeropoint fields. Such oscillatory behavior of the particles leads to the deviations in their path of motion. The oscillations of the particle in general may be considered as complex rotations in complex vector space. The local particle harmonic oscillator is analyzed in the complex vector formalism considering the algebra of complex vectors. The particle spin is viewed as zeropoint angular momentum represented by a bivector. It has been shown that the particle spin plays an important role in the kinematical intrinsic or local motion of the particle. From the complex vector formalism of harmonic oscillator, for the first time, a relation between mass and bivector spin has been derived in the form . Where, is the angular velocity bivector of complex rotations, is the velocity of light. The unit vector acts as an operator on the idempotents and to give the eigen values The constant represents two fold nature of the equation corresponding to particle and antiparticle states. Further the above relation shows that the mass of the particle may be interpreted as a local spatial complex rotation in the rest frame. This gives an insight into the nature of fundamental particles. When a particle is observed from an arbitrary frame of reference, it has been shown that the spatial complex rotation dictates the relativistic particle motion. The mathematical structure of complex vectors in space and spacetime is developed.

Muralidhar, K.

2014-03-01

333

Multiclass core vector machine  

Microsoft Academic Search

Even though several techniques have been proposed in the literature for achieving multi- class classication using Support Vector Ma- chine(SVM), the scalability aspect of these approaches to handle large data sets still needs much of exploration. Core Vector Ma- chine(CVM) is a technique for scaling up a two class SVM to handle large data sets. In this paper we propose

S. Asharaf; M. Narasimha Murty; Shirish Krishnaj Shevade

2007-01-01

334

Support Vector Data Description  

Microsoft Academic Search

Data domain description concerns the characterization of a data set. A good description covers all target data but includes no superfluous space. The boundary of a dataset can be used to detect novel data or outliers. We will present the Support Vector Data Description (SVDD) which is inspired by the Support Vector Classifier. It obtains a spherically shaped boundary around

David M. J. Tax; Robert P. W. Duin

2004-01-01

335

Fuzzy learning vector quantization  

Microsoft Academic Search

In this paper, a new supervised competitive learning network model called fuzzy learning vector quantization (FLVQ) which incorporates fuzzy concepts into the learning vector quantization (LVQ) networks is proposed. Unlike the original algorithm, the FLVQ's learning algorithm is derived from optimizing an appropriate fuzzy objective function which takes into accounts of two goals, namely, minimizing the network output error which

Fu-Lai Chung; Tong Lee

1993-01-01

336

Cloud Scaling Properties and Cloud Parameterization  

NASA Technical Reports Server (NTRS)

Cloud liquid and cloud traction variability is studied as a function of horizontal scale in the ECMWF forecast model during several 10-day runs at the highest available model resolution, recently refined from approximately 60 km (T213) down to approximately 20 km (T639). At higher resolutions, model plane-parallel albedo biases are reduced, so that models may be tuned to have larger, more realistic, cloud liquid water amounts, However, the distribution of cloud liquid assumed -within- each gridbox, for radiative and thermodynamic computations, depends on ad hoc assumptions that are not necessarily consistent with observed scaling properties, or with scaling properties produced by the model at larger scales. To study the larger-scale cloud properties, ten locations on the Earth are chosen to coincide with locations having considerable surface data available for validation, and representing a variety of climatic regimes, scaling exponents are determined from a range or scales down to model resolution, and are re-computed every three hours, separately for low, medium and high clouds, as well as column-integrated cloudiness. Cloud variability fluctuates in time, due to diurnal, synoptic and other' processes, but scaling exponents are found to be relatively stable. various approaches are considered for applying computed cloud scaling to subgrid cloud distributions used for radiation, beyond simple random or maximal overlap now in common use. Considerably more work is needed to compare model cloud scaling with observations. This will be aided by increased availability of high-resolution surface, aircraft and satellite data, and by the increasing resolution of global models,

Cahalan, R. F.; Morcrette, J. J.

1998-01-01

337

Velocity and Vorticity Measurements of Jupiter's Great Red Spot Using Automated Cloud Feature Trackers  

Microsoft Academic Search

We have produced mosaics of the Great Red Spot (GRS) using images taken by Galileo in May 2000, and have measured the winds of the GRS using an automated algorithm that does not require manual cloud tracking. Our technique yields a high-density, regular grid of wind velocity vectors that is advantageous over a limited number of scattered wind vectors that

David S. Choi; D. Banfield; P. J. Gierasch; A. P. Showman

2006-01-01

338

Self-Motion Perception and Motion Sickness  

NASA Technical Reports Server (NTRS)

Motion sickness typically is considered a bothersome artifact of exposure to passive motion in vehicles of conveyance. This condition seldom has significant impact on the health of individuals because it is of brief duration, it usually can be prevented by simply avoiding the eliciting condition and, when the conditions that produce it are unavoidable, sickness dissipates with continued exposure. The studies conducted examined several aspects of motion sickness in animal models. A principle objective of these studies was to investigate the neuroanatomy that is important in motion sickness with the objectives of examining both the utility of putative models and defining neural mechanisms that are important in motion sickness.

Fox, Robert A.

1991-01-01

339

Vector generator scan converter  

DOEpatents

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

Moore, J.M.; Leighton, J.F.

1988-02-05

340

Vector theories in cosmology  

SciTech Connect

This article provides a general study of the Hamiltonian stability and the hyperbolicity of vector field models involving both a general function of the Faraday tensor and its dual, f(F{sup 2},FF-tilde), as well as a Proca potential for the vector field, V(A{sup 2}). In particular it is demonstrated that theories involving only f(F{sup 2}) do not satisfy the hyperbolicity conditions. It is then shown that in this class of models, the cosmological dynamics always dilutes the vector field. In the case of a nonminimal coupling to gravity, it is established that theories involving Rf(A{sup 2}) or Rf(F{sup 2}) are generically pathologic. To finish, we exhibit a model where the vector field is not diluted during the cosmological evolution, because of a nonminimal vector field-curvature coupling which maintains second-order field equations. The relevance of such models for cosmology is discussed.

Esposito-Farese, Gilles; Pitrou, Cyril; Uzan, Jean-Philippe [GRECO, Institut d'Astrophysique de Paris, UMR 7095-CNRS, Universite Pierre et Marie Curie-Paris 6, 98bis boulevard Arago, F-75014 Paris (France); Institute of Cosmology and Gravitation, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); GRECO, Institut d'Astrophysique de Paris, UMR 7095-CNRS, Universite Pierre et Marie Curie-Paris 6, 98bis boulevard Arago, F-75014 Paris (France) and Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa)

2010-03-15

341

Frame concealment algorithm for stereoscopic video using motion vector sharing  

Microsoft Academic Search

Stereoscopic video is one of the simplest forms of multi view video, which can be easily adapted for communication applications. Much current research is based on colour and depth map stereoscopic video, due to its reduced bandwidth requirements and backward compatibility. Existing immersive media research is more focused on application processing than aspects related to transfer of immersive content over

Chaminda T. E. R. Hewage; Stewart Worrall; Safak Dogan; Ahmet M. Kondoz

2008-01-01

342

Magnetic structures inside boundary layers of magnetic clouds  

NASA Astrophysics Data System (ADS)

We analyze 23 magnetic cloud boundary layers (BLs) in Feb. 1995-Oct. 1998 and find that: (1) the distribution functions of fluctuations in the southward field component inside the boundary layer, ?BzL, is very different from ?BzS in the background solar wind and ?BzM inside the cloud, with the enhancement in the fluctuation amplitude and the variation of the magnitude and direction of the average field. (2) in the maximum variance plane (MVP) composed of the maximum and medium variance directions, the walk of the tips of the magnetic field vectors in the BL could be classified into two types based on: (a) field vectors vibrate along a circle arc, which is possibly related with Alfven fluctuations inside the BL; (b) field vectors walk randomly in the MVP, which could be correlated with the turbulence inside the BL. (3) In the ?-? plane, fields inside the BL exhibits a `U' or inverse `U' shape with a spacing of about 180 degree in the azimuthal angle, which indicate the existence of a field reverse region and are often associated with the Alfvenic fluctuations. The results above suggest that the cloud's BL owns the magnetic structure different from that in the solar wind and cloud body, which is a manifestation for the interaction of the magnetic cloud (MC) with the solar wind (SW).

Wei, Fengsi; Liu, Rui; Feng, Xueshang; Zhong, Dingkun; Yang, Fang

2003-12-01

343

Speed tuning of motion segmentation and discrimination  

NASA Technical Reports Server (NTRS)

Motion transparency requires that the visual system distinguish different motion vectors and selectively integrate similar motion vectors over space into the perception of multiple surfaces moving through or over each other. Using large-field (7 degrees x 7 degrees) displays containing two populations of random-dots moving in the same (horizontal) direction but at different speeds, we examined speed-based segmentation by measuring the speed difference above which observers can perceive two moving surfaces. We systematically investigated this 'speed-segmentation' threshold as a function of speed and stimulus duration, and found that it increases sharply for speeds above approximately 8 degrees/s. In addition, speed-segmentation thresholds decrease with stimulus duration out to approximately 200 ms. In contrast, under matched conditions, speed-discrimination thresholds stay low at least out to 16 degrees/s and decrease with increasing stimulus duration at a faster rate than for speed segmentation. Thus, motion segmentation and motion discrimination exhibit different speed selectivity and different temporal integration characteristics. Results are discussed in terms of the speed preferences of different neuronal populations within the primate visual cortex.

Masson, G. S.; Mestre, D. R.; Stone, L. S.

1999-01-01

344

Cloud microstructure studies  

NASA Technical Reports Server (NTRS)

Over two thousand individual cloud droplet size distributions were measured with an optical cloud particle spectrometer flown on the NASA Convair 990 aircraft. Representative droplet spectra and liquid water content, L (gm/cu m) were obtained for oceanic stratiform and cumuliform clouds. For non-precipitating clouds, values of L range from 0.1 gm/cu m to 0.5 gm/cu m; with precipitation, L is often greater than 1 gm/cu m. Measurements were also made in a newly formed contrail and in cirrus clouds.

Blau, H. H., Jr.; Fowler, M. G.; Chang, D. T.; Ryan, R. T.

1972-01-01

345

Seasonal Cloud Cover Variations  

NSDL National Science Digital Library

This lesson is designed to help students gain knowledge in using the MY NASA DATA Live Access Server (LAS) to specify and download a microset of data, then to use the data to determine the seasonal cloud coverage and the occurrence of different cloud types, by percent, in the North Carolina (or their local area). Students will identify different cloud types and determine their seasonality. They will graph the data and explore whether there is a correlation between season, cloud cover and type of cloud most prevalent during each season. The lesson provides detailed procedure, related links and sample graphs, follow-up questions and extensions, and Teacher Notes.

2010-03-14

346

Dispersion of Magnetic Fields in Molecular Clouds  

NASA Astrophysics Data System (ADS)

Chandrasekhar & Fermi (1953) used the dispersion of starlight polarization vectors about contours of Galactic latitude to determine the strength of the magnetic field in the arms of the Galaxy. The same technique, the Chandrasekhar Fermi (CF) method, has been applied to estimates of field strengths in the relatively dense medium of molecular clouds. The basis for deriving field strengths from dispersion measurements is the same for observations of Galactic arms or molecular clouds: in either case dispersion decreases as the field strengthens. But in the case of the Galactic arms, the dispersion is due to magnetohydrodynamic (MHD) waves; the displacements are perpendicular to the direction of propagation. In the case of turbulent dispersion in molecular clouds, there is no preferred direction. The turbulent component can be in any orientation and may have structure due to effects such as differential rotation, gravitational collapse, or expanding H II regions. Consequently, dispersion measured about mean fields, assumed straight, may be much larger than should be attributed to MHD waves or turbulence. Dispersion measured about model large-scale fields that give approximate fits to a polarization map will result in better estimates but still give inaccurate values of the turbulent component. Here we describe a method for determining magnetic field dispersion about local structured fields, without assuming any model for the large-scale field. To do this, we use the second-order structure function of the measured polarization vectors to separate the turbulent component of the dispersion from the large-scale field. Our study incorporates the effect on the measured dispersion of signal integration through the thickness of the cloud as well as across the area subtended by the telescope beam. Our method provides accurate, independent estimates of the turbulent to mean magnetic field strength ratio. We discuss applications to the molecular clouds Orion, M17, and DR21.

Vaillancourt, John E.; Hildebrand, R. H.; Houde, M.

2009-05-01

347

Dispersion of Magnetic Fields in Molecular Clouds  

NASA Astrophysics Data System (ADS)

Chandrasekhar & Fermi (1953) used the dispersion of starlight polarization vectors about contours of Galactic latitude to determine the strength of the magnetic field in the arms of the Galaxy. The same technique, the Chandrasekhar-Fermi (CF) method, has been applied to estimates of field strengths in the relatively dense medium of molecular clouds. The basis for deriving field strengths from dispersion measurements is the same for observations of Galactic arms or molecular clouds: in either case dispersion decreases as the field strengthens. But in the case of the Galactic arms, the dispersion is due to magnetohydrodynamic (MHD) waves; the displacements are perpendicular to the direction of propagation. In the case of turbulent dispersion in molecular clouds, there is no preferred direction. The turbulent component can be in any orientation and may have structure due to effects such as differential rotation, gravitational collapse, or expanding H II regions. Consequently, dispersion measured about mean fields, assumed straight, may be much larger than should be attributed to MHD waves or turbulence. Dispersion measured about model large-scale fields that give approximate fits to a polarization map will result in better estimates but still give inaccurate values of the turbulent component. Here we describe a method for determining magnetic field dispersion about local structured fields, without assuming any model for the large-scale field. To do this, we use the second-order structure function of the measured polarization vectors to separate the turbulent component of the dispersion from the large-scale field. Our study incorporates the effect on the measured dispersion of signal integration through the thickness of the cloud as well as across the area subtended by the telescope beam. Our method provides accurate, independent estimates of the turbulent to mean magnetic field strength ratio. We discuss applications to the molecular clouds Orion, M17, and DR21.

Vaillancourt, John E.; Houde, M.; Hildebrand, R. H.

2010-01-01

348

A Hierarchical Modeling Study of the Interactions Among Turbulence, Cloud Microphysics, and Radiative Transfer in the Evolution of Cirrus Clouds  

NASA Technical Reports Server (NTRS)

This project used a hierarchy of cloud resolving models to address the following science issues of relevance to CRYSTAL-FACE: What ice crystal nucleation mechanisms are active in the different types of cirrus clouds in the Florida area and how do these different nucleation processes influence the evolution of the cloud system and the upper tropospheric humidity? How does the feedback between supersaturation and nucleation impact the evolution of the cloud? What is the relative importance of the large-scale vertical motion and the turbulent motions in the evolution of the crystal size spectra? How does the size spectra impact the life-cycle of the cloud, stratospheric dehydration, and cloud radiative forcing? What is the nature of the turbulence and waves in the upper troposphere generated by precipitating deep convective cloud systems? How do cirrus microphysical and optical properties vary with the small-scale dynamics? How do turbulence and waves in the upper troposphere influence the cross-tropopause mixing and stratospheric and upper tropospheric humidity? The models used in this study were: 2-D hydrostatic model with explicit microphysics that can account for 30 size bins for both the droplet and crystal size spectra. Notably, a new ice crystal nucleation scheme has been incorporated into the model. Parcel model with explicit microphysics, for developing and evaluating microphysical parameterizations. Single column model for testing bulk microphysics parameterizations

Curry, Judith; Khvorostyanov, V. I.

2005-01-01

349

Homogeneous ice nucleation and supercooled liquid water in orographic wave clouds  

Microsoft Academic Search

This study investigates ice nucleation mechanisms in cold lenticular wave clouds, a cloud type characterized by quasi-steady-state air motions and microphysical properties. It is concluded that homogeneous ice nucleation is responsible for the ice production in these clouds at temperatures below about -33[degrees]C. The lack of ice nucleation observed above -33[degrees]C indicates a dearth of ice-forming nuclei, and hence heterogeneous

Andrew J. Heymsfield; Larry M. Miloshevich

1993-01-01

350

Inhibition and facilitation of apparent motion by real motion.  

PubMed

Observers viewed a CRT display which contained both real and apparent motion. When the apparent motion was in the same direction as the real motion, the strength of the apparent motion was enhanced. Real motion in the opposite direction completely cancelled apparent motion. However, the appearance of the real motion was not affected by apparent motion. PMID:6636545

Green, M

1983-01-01

351

An inquiry into the cirrus-cloud thermostat effect for tropical sea surface temperature  

Microsoft Academic Search

In this paper, we investigate the relative importance of local vs remote control on cloud radiative forcing using a cumulus ensemble model. It is found that cloud and surface radiation forcings are much more sensitive to the mean vertical motion assoicated with large scale tropical circulation than to the local SST (sea surface temperature). When the local SST is increased

C.-H. Suil

1994-01-01

352

Movie of High Clouds on Jupiter  

NASA Technical Reports Server (NTRS)

Jupiter's high-altitude clouds are seen in this brief movie made from seven frames taken by the narrow-angle camera of NASA's Cassini spacecraft. This is the first time a movie sequence of Jupiter has been made that illustrates the motions of the high-altitude clouds on a global scale.

The images were taken at a wavelength that is absorbed by methane, one chemical in Jupiter's lower clouds. So, dark areas are relatively free of high clouds, and the camera sees through to the methane in a lower level. Bright areas are places with high, thick clouds that shield the methane below.

Jupiter's equator and Great Red Spot are covered with high-altitude, hazy clouds.

The movie covers the time period between Oct. 1 and Oct. 5, 2000, latitudes from 50 degrees north to 50 degrees south, and a 100-degree sweep of longitude. Those factors were the same for a Cassini movie of cloud motions previously released (PIA02829), but that movie used frames taken through a blue filter, which showed deeper cloud levels and sharper detail. Features in this methane-filter movie appear more diffuse.

Among the nearly stationary features are the Red Spot and some bright ovals at mid-latitudes in both hemispheres. These are anticyclonic (counter-clockwise rotating) storms. They are bright in the methane band because of their high clouds associated with rising gas. They behave differently from terrestrial cyclones, which swirl in the opposite direction. The mechanism making the Red Spot and similar spots stable apparently has no similarity to the mechanism which feeds terrestrial cyclones.

Some small-scale features are fascinating because of their brightness fluctuations. Such fluctuations observed in the methane band are probably caused by strong vertical motions, which form clouds rapidly, as in Earth's thunderstorms. Near the upper left corner in this movie, a number of smaller clouds appear to circulate counterclockwise around a dark spot, and these clouds fluctuate in brightness, so they may be candidates for lightning storms.

A pattern of lighter areas between darker patches can be seen in the darkest band a little north of the bright equatorial region. This may be tied to a wave-like temperature variation across the planet. If confirmed, this would be the first time such large-scale stratospheric temperature waves have been visibly linked to variations in haze thickness.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

2000-01-01

353

Impact of the ice phase on a mesoscale convective system: Implication of cloud parameterization and cloud radiative properties  

SciTech Connect

This study attempts to provide further understanding of the effect of the ice phase on cloud ensemble features which are useful for improving GCM cumulus parameterization. In addition, cloud model results are used to diagnose the radiative properties of anvils in order to assess cloud/radiation interaction and its feedback on the larger-scale climate for the future work. The heat, moisture and mass budget analyses of a simulated squall line system indicate that, at least for this type of system, the inclusion of the ice phase in the microphysics does not considerably change the net cloud heating and drying effects and the feedback on the large-scale motion. Nonetheless, its impact on the radiative properties of clouds significantly influences not only the squall line system itself, but also the larger-scale circulation due to the favorable stratification for long-lasting anvil clouds. The water budget suggests a simple methodology to parameterize the microphysical effect without considering it as a model physics module. Further application of the water budget might also be used to parameterize the cloud transport of condensates in the anvil cloud region, which allows the GCM columns to interact with each other. The findings of this study suggest that the ice phase could be ignored in the cloud parameterization in order to save significant amounts of computational resources and to simplify the model physics. More scientific effort should, however, be focused on the effect of the ice phase to further explore cloud feedback on the large-scale climate through the radiative process. The cloud/radiation interaction and its feedback on the larger-scale climate will be addressed in a companion study by coupling the radiative transfer model with the cloud model. 19 refs., 13 figs.

Chin, H.N.S.; Bradley, M.M.; Molenkamp, C.R.; Grant, K.E.; Chuang, C.

1991-08-01

354

Approximation and visualization of large-scale motion of protein surfaces.  

PubMed

We present a method for the approximation and real-time visualization of large-scale motion of protein surfaces. A molecular surface is represented by an expansion of spherical harmonic functions, and the motion of protein atoms around their equilibrium positions is computed by normal mode analysis. The motion of the surface is approximated by projecting the normal mode vectors of the solvent-accessible atoms to the spherical harmonic representation of the molecular surface. These surface motion vectors are represented by a separate spherical harmonic expansion. Representing the surface geometry and the surface motion vectors by spherical harmonic expansions allows variable-resolution analysis and real-time display of the large-scale surface motion. This technique has been applied to interactive visualization, interactive surface manipulation, and animation. PMID:8527417

Duncan, B S; Olson, A J

1995-08-01

355

The Cloud Radar System  

NASA Technical Reports Server (NTRS)

Improvement in our understanding of the radiative impact of clouds on the climate system requires a comprehensive view of clouds including their physical dimensions, dynamical generation processes, and detailed microphysical properties. To this end, millimeter vave radar is a powerful tool by which clouds can be remotely sensed. The NASA Goddard Space Flight Center has developed the Cloud Radar System (CRS). CRS is a highly sensitive 94 GHz (W-band) pulsed-Doppler polarimetric radar that is designed to fly on board the NASA high-altitude ER-2 aircraft. The instrument is currently the only millimeter wave radar capable of cloud and precipitation measurements from above most all clouds. Because it operates from high-altitude, the CRS provides a unique measurement perspective for cirrus cloud studies. The CRS emulates a satellite view of clouds and precipitation systems thus providing valuable measurements for the implementation and algorithm validation for the upcoming NASA CloudSat mission that is designed to measure ice cloud distributions on the global scale using a spaceborne 94 GHz radar. This paper describes the CRS instrument and preliminary data from the recent Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE). The radar design is discussed. Characteristics of the radar are given. A block diagram illustrating functional components of the radar is shown. The performance of the CRS during the CRYSTAL-FACE campaign is discussed.

Racette, Paul; Heymsfield, Gerald; Li, Lihua; Tian, Lin; Zenker, Ed

2003-01-01

356

THE CALIFORNIA MOLECULAR CLOUD  

SciTech Connect

We present an analysis of wide-field infrared extinction maps of a region in Perseus just north of the Taurus-Auriga dark cloud complex. From this analysis we have identified a massive, nearby, but previously unrecognized, giant molecular cloud (GMC). Both a uniform foreground star density and measurements of the cloud's velocity field from CO observations indicate that this cloud is likely a coherent structure at a single distance. From comparison of foreground star counts with Galactic models, we derive a distance of 450 +- 23 pc to the cloud. At this distance the cloud extends over roughly 80 pc and has a mass of {approx} 10{sup 5} M{sub sun}, rivaling the Orion (A) molecular cloud as the largest and most massive GMC in the solar neighborhood. Although surprisingly similar in mass and size to the more famous Orion molecular cloud (OMC) the newly recognized cloud displays significantly less star formation activity with more than an order of magnitude fewer young stellar objects than found in the OMC, suggesting that both the level of star formation and perhaps the star formation rate in this cloud are an order of magnitude or more lower than in the OMC. Analysis of extinction maps of both clouds shows that the new cloud contains only 10% the amount of high extinction (A{sub K} > 1.0 mag) material as is found in the OMC. This, in turn, suggests that the level of star formation activity and perhaps the star formation rate in these two clouds may be directly proportional to the total amount of high extinction material and presumably high density gas within them and that there might be a density threshold for star formation on the order of n(H{sub 2}) {approx} a few x 10{sup 4} cm{sup -3}.

Lada, Charles J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lombardi, Marco [European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748, Garching (Germany); Alves, Joao F., E-mail: clada@cfa.harvard.ed, E-mail: mlombard@eso.or, E-mail: jalves@caha.e [Calar Alto Observatory, C/Jesus Durban Remon, 2-2, 04004 Almeria (Spain)

2009-09-20

357

Vector Mesons at HERA  

SciTech Connect

The rich experimental landscape of exclusive vector meson production at the high energy electron-proton collider HERA is reviewed, with emphasis on the transition from soft to hard diffraction and perturbative QCD interpretations.

Favart, L

2009-03-23

358

Diffractive vector meson production  

NASA Astrophysics Data System (ADS)

This is a brief introduction to diffractive vector meson production, both exclusive ?p?V and large momentum transfer ?p?VX processes. I overview the theoretical basis for the perturbative description and some recent developments.

Enberg, R.

2005-06-01

359

Baculovirus as vaccine vectors.  

PubMed

Application of viral vectors derived from human viruses to mediate immune response in animals and humans has been greatly hampered by the problems associated with pre-existing immunity and associated toxicities. Among few non-human viral vectors, baculovirus has now evolved as a novel tool for vaccine vector development. With broad tissue tropism and expanded bio-safety profile suitably supplemented with intrinsic immunostimulatory properties, baculovirus has now attained a niche position in the arena of vaccine development. Recombinant envelope-modified baculovirus equipped with novel shuttle promoters for in vivo transduction has shown promising results in several animal models. Baculovirus mediated induction of systemic and mucosal immune responses through intranasal or oral administration has now open an entirely new way for the development of new generation vaccines. Gaining additional insight into the baculovirus biology and its interaction with non-native hosts will certainly promote this human-friendly virus as a potential vector for clinical applications. PMID:20394572

Madhan, Selvaraj; Prabakaran, Mookkan; Kwang, Jimmy

2010-06-01

360

Poynting-vector filter  

DOEpatents

A determination is made of frequency components associated with a particular bearing or location resulting from sources emitting electromagnetic-wave energy for which a Poynting-Vector can be defined. The broadband frequency components associated with a specific direction or location of interest are isolated from other components in the power spectrum that are not associated with the direction or location of interest. The collection of pointing vectors can be used to characterize the source.

Carrigan, Charles R. (Tracy, CA)

2011-08-02

361

Scanning Cloud Radar Observations at the ARM sites  

NASA Astrophysics Data System (ADS)

Recently, the DOE Atmospheric Radiation Measurement (ARM) program upgraded its fixed and mobile facilities with the acquisition of state-of-the-art scanning, dual-wavelength, polarimetric, Doppler cloud radars. The scanning ARM cloud radars (SACR's) are the most expensive and significant radar systems at all ARM sites and eight SACR systems will be operational at ARM sites by the end of 2013. The SACR's are the primary instruments for the detection of 3D cloud properties (boundaries, volume cloud fractional coverage, liquid water content, dynamics, etc.) beyond the soda-straw (profiling) limited view. Having scanning capabilities with two frequencies and polarization allows more accurate probing of a variety of cloud systems (e.g., drizzle and shallow, warm rain), better correction for attenuation, use of attenuation for liquid water content retrievals, and polarimetric and dual-wavelength ratio characterization of non-spherical particles for improved ice crystal habit identification. Examples of SACR observations from four ARM sites are presented here: the fixed sites at Southern Great Plains (SGP) and North Slope of Alaska (NSA), and the mobile facility deployments at Graciosa Island, Azores and Cape Cod, Massachusetts. The 3D cloud structure is investigated both at the macro-scale (20-50 km) and cloud-scale (100-500 m). Doppler velocity measurements are corrected for velocity folding and are used either to describe the in-cloud horizontal wind profile or the 3D vertical air motions.

Kollias, P.; Clothiaux, E. E.; Shupe, M.; Widener, K.; Bharadwaj, N.; Miller, M. A.; Verlinde, H.; Luke, E. P.; Johnson, K. L.; Jo, I.; Tatarevic, A.; Lamer, K.

2012-12-01

362

Cloud Computing in Virtual Environments  

Microsoft Academic Search

In this paper we present the basis of a new middleware service that provisions clouds for virtual organizations (VOs).This service makes use of a virtual environment's inherent ability to render objects to represent clouds with real clouds. These clouds are created on demand by avatars and tagged to provide a rudimentary semantic that can be used for searching. Clouds are

Kristen Hardwick; John Fisher; Ben Sterrett; Christine Minor; Sebastien Goasguen

2009-01-01

363

New techniques in 3D scalar and vector field visualization  

SciTech Connect

At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.

Max, N.; Crawfis, R.; Becker, B.

1993-05-05

364

Introduction to Clouds  

NSDL National Science Digital Library

This site gives students an opportunity to explore storm clouds and climate change through the use of National Aeronautic and Space Administration (NASA) climate research data obtained through satellite imaging. The challenge is to investigate actual scientific research data on clouds and storms, and make the resulting observations and interpretations available to NASA research scientists for review. The interactive site will allow students to discover what the major types of clouds produced by storms are and whether these clouds help to cool or warm the Earth's surface. Storms are the major producers of clouds in the Earth's atmosphere, so students investigate the relationship between the types of clouds in order to make their conclusions.

365

Energy Aware Clouds  

NASA Astrophysics Data System (ADS)

Cloud infrastructures are increasingly becoming essential components for providing Internet services. By benefiting from economies of scale, Clouds can efficiently manage and offer a virtually unlimited number of resources and can minimize the costs incurred by organizations when providing Internet services. However, as Cloud providers often rely on large data centres to sustain their business and offer the resources that users need, the energy consumed by Cloud infrastructures has become a key environmental and economical concern. This chapter presents an overview of techniques that can improve the energy efficiency of Cloud infrastructures. We propose a framework termed as Green Open Cloud, which uses energy efficient solutions for virtualized environments; the framework is validated on a reference scenario.

Orgerie, Anne-Cécile; de Assunção, Marcos Dias; Lefèvre, Laurent

366

Light vector mesons in the nuclear medium  

NASA Astrophysics Data System (ADS)

The light vector mesons (?,?, and ?) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the ? meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to e+e-. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The ?-meson mass spectrum was extracted after the ? and ? signals were removed in a nearly model-independent way. Comparisons were made between the ? mass spectra from the heavy targets (A>2) with the mass spectrum extracted from the deuterium target. With respect to the ?-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion.

Wood, M. H.; Nasseripour, R.; Weygand, D. P.; Djalali, C.; Tur, C.; Mosel, U.; Muehlich, P.; Adams, G.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Battaglieri, M.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Blaszczyk, L.; Bouchigny, S.; Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Casey, L.; Chen, S.; Cheng, L.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dickson, R.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Fradi, A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hanretty, C.; Hardie, J.; Hassall, N.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Kellie, J. D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Kossov, M.; Krahn, Z.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Livingston, K.; Lu, H. Y.; MacCormick, M.; Markov, N.; Mattione, P.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Sabatié, F.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shvedunov, N. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S.; Stepanyan, S. S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Williams, M.; Wolin, E.; Yegneswaran, A.; Zana, L.; Zhang, B.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2008-07-01

367

GPS constraints on Africa (Nubia) and Arabia plate motions  

Microsoft Academic Search

We use continuously recording GPS (CGPS) and survey-mode GPS (SGPS) observations to determine Euler vectors for relative motion of the African (Nubian), Arabian and Eurasian plates. We present a well-constrained Eurasia-Nubia Euler vector derived from 23 IGS sites in Europe and four CGPS and three SGPS sites on the Nubian Plate (-0.95 +\\/- 4.8°N, -21.8 +\\/- 4.3°E, 0.06 +\\/- 0.005°

S. McClusky; R. Reilinger; S. Mahmoud; D. Ben Sari; A. Tealeb

2003-01-01

368

Three Clouds Activity  

NSDL National Science Digital Library

The University of Michigan's educational site called Windows to the Universe (last mentioned in the January 6, 1999 Scout Report for Science and Engineering) has added many new lessons to their content. Highlights of these include two activities centered around cloud formation. The Three Clouds uses items such as a jugs and jars, a plastic bag, an aquarium thermometer, and an overhead projector to explore how clouds form and the relationship between the hydrosphere and human activity.

1995-01-01

369

Ammonia Clouds on Jupiter  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on the image for movie of Ammonia Ice Clouds on Jupiter

In this movie, put together from false-color images taken by the New Horizons Ralph instrument as the spacecraft flew past Jupiter in early 2007, show ammonia clouds (appearing as bright blue areas) as they form and disperse over five successive Jupiter 'days.' Scientists noted how the larger cloud travels along with a small, local deep hole.

2007-01-01

370

Cryptographic Cloud Storage  

NASA Astrophysics Data System (ADS)

We consider the problem of building a secure cloud storage service on top of a public cloud infrastructure where the service provider is not completely trusted by the customer. We describe, at a high level, several architectures that combine recent and non-standard cryptographic primitives in order to achieve our goal. We survey the benefits such an architecture would provide to both customers and service providers and give an overview of recent advances in cryptography motivated specifically by cloud storage.

Kamara, Seny; Lauter, Kristin

371

Cloud Infrastructure Security  

Microsoft Academic Search

\\u000a Cloud computing can help companies accomplish more by eliminating the physical bonds between an IT infrastructure and its\\u000a users. Users can purchase services from a cloud environment that could allow them to save money and focus on their core business.\\u000a At the same time certain concerns have emerged as potential barriers to rapid adoption of cloud services such as security,

Dimiter Velev; Plamena Zlateva

2010-01-01

372

Nonrigid Motion Analysis: Articulated and Elastic Motion  

Microsoft Academic Search

Motion of physical objects in the world is, in general, nonrigid. In robotics and computer vision, the motion of nonrigid objects is of growing interest to researchers from a wide spectrum of disciplines. The nonrigid objects being studied may be generally categorized into three groups according to the degree of deformation of body parts: articulated, elastic, and fluid. In articulated

Jake K. Aggarwal; Quin Cai; Wen-hung Liao; Bikash Sabata

1998-01-01

373

Microbiologists search the clouds  

NASA Astrophysics Data System (ADS)

On 22 May, a team of microbiologists used a prototype cloud-catcher mounted on a research plane to collect samples from low-lying cumulus clouds near Oxford, England. The researchers, from the University of East London (UEL), are investigating whether an active and self-sustaining ecosystem exists in clouds, and whether airborne microbes may play an active role in forming clouds and causing rainfall.While scientists have known that microorganisms, including bacteria, fungal spores, and algae, can survive and possibly reproduce in the atmosphere, the challenge, according to the UEL researchers, is to accurately detect, identify, and analyze microbial communities.

Showstack, Randy

374

Dynamics of a Jet\\/Cloud Collision in Astrophysics and in the Laboratory  

Microsoft Academic Search

HH 110 is an extraordinary stream of shocked gas that forms when a highly supersonic jet from a young star impacts a dense dark cloud at an oblique angle. Previous spectra of this source fail by a factors of ~ 5 to reach the thermal broadening limit, which is required to distinguish bulk motion, turbulence, and thermal motions from one

Patrick Hartigan; Adam Frank; John Foster; Paula Rosen; Robert Carver; Jacob Palmer; Bernie Wilde; Rob Coker; Fred Hansen; Brent Blue; Robin Williams

2007-01-01

375

On the Kinematics of Undulator Girder Motion  

SciTech Connect

The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.

Welch, J; /SLAC; ,

2011-08-18

376

Perceptual asynchrony for motion  

PubMed Central

Psychophysical experiments show that two different visual attributes, color and motion, processed in different areas of the visual brain, are perceived at different times relative to each other (Moutoussis and Zeki, 1997a). Here we demonstrate psychophysically that two variants of the same attribute, motion, which have the same temporal structure and are processed in the same visual areas, are also processed asynchronously. When subjects were asked to pair up–down motion of dots in one half of their hemifield with up-right motion in the other, they perceived the two directions of motion asynchronously, with the advantage in favor of up-right motion; when they were asked to pair the motion of white dots moving against a black background with that of red dots moving against an equiluminant green background, they perceived the luminant motion first, thus demonstrating a perceptual advantage of luminant over equiluminant motion. These results were not affected by motion speed or perceived motion “streaks.” We thus interpret these results to reflect the different processing times produced by luminant and equiluminant motion stimuli or by different degrees of motion direction change, thus adding to the evidence that processing time within the visual system is a major determinant of perceptual time.

Lo, Yu Tung; Zeki, Semir

2014-01-01

377

On helical vortex motions of moist air  

NASA Astrophysics Data System (ADS)

Two results that are fundamentally different from what takes place in a dry atmosphere have been obtained for adiabatic motions of unsaturated moist air: (1) the steady helical motion of moist air with collinear velocity and vorticity vectors everywhere is dynamically impossible; (2) the spontaneous amplification (generation) of helicity in a moist air due to baroclinicity is dynamically and thermodynamically feasible. In the absence of helicity flux through the boundary of the domain occupied by air flows, the difference between the values of integral helicity H at time instant t delaying at a small time interval from the initial instant t 0 (at which the instantaneous state of air motion is isomorphic either to a steady Beltrami flow or to an irrotational flow) and the initial value of H increases proportionally to ( t - t 0)4. The nonzero value of the proportionality factor is ensured by the difference in values of the Poisson ratio for dry air and water vapor, respectively.

Kurgansky, M. V.

2013-09-01

378

Contextual motion field-based distance for video analysis  

Microsoft Academic Search

In this work, we propose a general method for computing distance between video frames or sequences. Unlike conventional appearance-based\\u000a methods, we first extract motion fields from original videos. To avoid the huge memory requirement demanded by the previous\\u000a approaches, we utilize the “bag of motion vectors” model, and select Gaussian mixture model as compact representation. Thus,\\u000a estimating distance between two

Yadong Mu; Shuicheng Yan; Thomas S. Huang; Bingfeng Zhou

2008-01-01

379

Computational-complexity scalable motion estimation for mobile MPEG encoding  

Microsoft Academic Search

Complexity scalability algorithms are important for mobile consumer devices using MPEG video coding, because they offer a trade-off between picture quality and the embedded available computational performance. This paper presents a new scalable three-stage motion estimation technique, which includes preprocessing of frames in display order and approximation of motion-vector fields using multiple temporal references. A quality refinement of the approximation

Stephan Mietens; C. Hentschel

2004-01-01

380

Valles Marineris cloud trails  

NASA Astrophysics Data System (ADS)

Distinctive cloud trails are identified in Mars Reconnaissance Orbiter Mars Color Imager (MARCI) images over specific locations associated with Valles Marineris and Noctis Labyrinthus and at perihelion solar longitudes (LS = 230°-260°). High-contrast surface shadows are well defined, as cast from their eastern margins, supporting altitude and optical depth determinations. These relatively high altitude clouds (40-50 km) exhibit narrow latitudinal widths (25-75 km) in comparison to extended longitudinal dimensions (400-1000 km). MARCI multispectral imaging of cloud surface shadows in five wavelength channels (260, 320, 437, 546, and 653 nm) yields the wavelength dependence of cloud extinction optical depth, revealing a range of small cloud particle sizes (reff = 0.2-0.5 ?m) and moderate cloud optical depths (0.03-0.10 visible and 0.1-0.2 ultraviolet). Local time and temporal sampling characteristics of MARCI cloud images indicate that these clouds develop very rapidly in afternoon hours (1300-1500 LT), reach their full longitudinal extents within <2 h time scales, and often reoccur on successive afternoons. Mars Global Surveyor Mars Orbital Camera imaging in previous Mars years indicates these clouds are annually repeating. These observed characteristics suggest a cloud formation mechanism that is specific to ˜50 km horizontal and vertical scales, transports water vapor and dust upward from lower levels, exists during the afternoon, and is likely associated with the mesoscale atmospheric circulations induced by the near-equatorial canyons of Mars. Cloud particles formed in such updrafts would then be rapidly transported westward in the strong retrograde zonal circulation of the subsolar middle atmosphere in this season.

Clancy, R. Todd; Wolff, Michael J.; Cantor, Bruce A.; Malin, Michael C.; Michaels, Timothy I.

2009-11-01

381

Conceptualizing Mathematics "Motion Problems"  

ERIC Educational Resources Information Center

Describes an instructional method in secondary school mathematics applicable to physics instruction, to develop conceptual understanding of motion word problems. Distance, rate, and time are defined, used as variables and considered with relative motion as a unifying concept. (JM)

McKeough, William J.

1970-01-01

382

Relation of Cloud Occurrence Frequency, Overlap, and Effective Thickness Derived from CALIPSO and CloudSat Merged Cloud Vertical Profiles.  

National Technical Information Service (NTIS)

A cloud frequency of occurrence matrix is generated using merged cloud vertical profile derived from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR). The matrix contains vertical profiles of cloud occurrence frequ...

B. A. Wielicki F. G. Rose P. Minnis S. Kato S. Sun-Mack W. F. Miller Y. Chen

2009-01-01

383

Continuous Motion Morphing  

Microsoft Academic Search

We present an extension to a previous morphing method for human motion. It works on motion capture data that is segmented into movement elements. Our new timewarping algorithm accepts time-dependent continuous functions as input for the morphing coecients without introducing foot sliding. It is designed for creating new natural looking motions from given prototype motions. We employ a zero-moment-point criterion

Johannes Mezger; Winfried Ilg; Martin Giese

384

Force and Motion  

NSDL National Science Digital Library

Explore interactive sites and sites with information about putting objects into motion with different forces. 1. Read the top two sections about Motion and Force and then answer questions #1 and #2 on your worksheet. Force and Motion Information 2. Scroll down and read the section about inertia. Force and Motion Information Then click the box that says "law of inertia" and learn more about inertia on this page. Newton s Laws Now answer #3 ...

Benson, Carrie

2013-01-31

385

Biosafety of lentiviral vectors.  

PubMed

The characteristics of lentiviral vectors (stable integration in non-dividing and dividing cells, long-term expression of the transgene, absence of immune response) make them ideal gene transfer vehicula for future gene therapy. However, the most potent lentiviral vectors are derived from highly pathogenic human viruses, such as HIV. We describe how the field has engineered lentivectors with increasing biosafety both for the lab worker and for the patient. The risk associated with state-of-the-art lentivectors is therefore minimal, although a psychological barrier to use these vectors in the clinic may still have to be overcome. Due to their increased performance, care should be taken to avoid accidental transduction of the lab worker with potential hazardous genes. The precautions which have to be taken are described in detail. PMID:14683448

Debyser, Zeger

2003-12-01

386

MPLNET Version 3 Cloud Algorithm  

NASA Astrophysics Data System (ADS)

The Micropulse Lidar Network version 3 cloud detection algorithm is described. Differences between the new cloud algorithm and the previous version are highlighted. The algortihm uses thresholds in the derivative of the attenuated calibration profile to identify low-level clouds and the signal uncertainty to identify higher clouds. Cirrus clouds are identified using the cloud top temperature derived from NCEP reanalysis. To demonstrate the performance of the new algorithm, a multiyear vertical distribution of clouds is shown from measurements at the Goddard Space Flight Center (Greenbelt, MD) and Singapore sites. Seasonal and diurnal statistics on the cloud base, apparent top, temperature, phase, optical thinkness, and frequency of occurrence are featured.

Lewis, J. R.; Campbell, J. R.; Welton, E. J.

2013-12-01

387

Stereoscopic Motion Tracking System  

Microsoft Academic Search

A Stereoscopic Motion Tracking System is being developed for use with a video game system for rehabilitation of children affected by Cerebral Palsy. Two cameras will be used to track the (x, y) locationof a motion, using stereoscopic principles this data will be used to calculate the Z locationof the motion. This data will be collected for the duration of

A. Calderon; M. Dembele; B. Hossain; Y. Noor; S. Ovsiew

2011-01-01

388

Plates and their motions  

NASA Technical Reports Server (NTRS)

Work on plate motions published in 1983-1986 and in early 1987 is reviewed. Models for these motions, including global ones for driving forces and local ones for subduction history and back-arc spreading, are addressed. The problem of reference frames, both hotspot and paleomagnetic, is discussed. The assessment of errors in plate motion studies is reviewed.

Jurdy, Donna M.

1987-01-01

389

Objects in Motion  

ERIC Educational Resources Information Center

One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

Damonte, Kathleen

2004-01-01

390

Relative-Motion Microworld.  

National Technical Information Service (NTIS)

A relative-motion microworld has been designed to aid high-school students in understanding the concepts of relative motion and frames of reference. Relative motion and frames of reference are usually introduced in a high-school physics or mathematics cou...

L. E. Morecroft

1985-01-01

391

Motion signal processing  

Microsoft Academic Search

Techniques from the image and signal processing domain can be successfully applied to designing, modifying, and adapting ani- mated motion. For this purpose, we introduce multiresolution mo- tion filtering, multitarget motion interpolation with dynamic time- warping, waveshaping and motion displacement mapping. The techniques are well-suited for reuse and adaptation of existing mo- tion data such as joint angles, joint coordinates

Armin Bruderlin; Lance Williams

1995-01-01

392

Dizziness and Motion Sickness  

MedlinePLUS

Dizziness and Motion Sickness Dizziness and Motion Sickness Patient Health Information News media interested in covering the latest from AAO-HNS/F ... other respiratory infections If you are subject to motion sickness: ?Do not read while traveling ?Avoid sitting in ...

393

On the origin of the Orion and Monoceros molecular cloud complexes  

NASA Technical Reports Server (NTRS)

A detailed model for the origin of the Orion and Monoceros cloud complexes is presented, showing that a single high-velocity H I cloud-galaxy collision can explain their main observed features. The collision generates massive shocked layers, and self-gravity can then provide the conditions for the transformation of these layers into molecular clouds. The clouds formed by the collision maintain the motion of their parental shocked gas and reach positions located far away from the plane. According to this model, both the Orion and Monoceros complexes were formed some 60 million yr ago, when the original shocked layer was fragmented by Galactic tidal forces.

Franco, J.; Tenorio-Tagle, G.; Bodenheimer, P.; Rozyczka, M.; Mirabel, I. F.

1988-01-01

394

Clues About Clouds  

NSDL National Science Digital Library

In this weather activity which requires adult supervision, learners will get a chance to make a cloud right here on Earth! They learn about the different ingredients a cloud needs in order to form, and then duplicate the process that usually takes place thousands of feet above their heads.

Cosi

2009-01-01

395

Smoke Above Clouds  

NASA Technical Reports Server (NTRS)

Aerosols in the atmosphere alter the radiative balance of the Earth by reflecting or absorbing solar radiation. Spaceborne measurements of clouds and aerosols advected over the southeastern Atlantic Ocean indicate that the greater the cloud cover below the aerosols, the more likely the aerosols are to heat the planet.

Remer, Lorraine A.

2009-01-01

396

Canopy In The Clouds  

NSDL National Science Digital Library

Canopy In The Clouds is a free educational research focused on providing innovative and immersive earth and life science educational media from the perspective of a tropical montane clouds forest. All information on the website is peer-reviewed for accuracy and continually updated.

397

The Stories Clouds Tell  

NSDL National Science Digital Library

This book is a basic guide to the study of clouds. It features descriptions, photographs, and diagrams of various types of clouds. The book is accompanied by a set of slides. It was produced as part of Project ATMOSPHERE, an educational initiative of the American Meteorological Society.

Lemone, Margaret

2005-03-10

398

Cloud Resolving Modeling  

NASA Technical Reports Server (NTRS)

One of the most promising methods to test the representation of cloud processes used in climate models is to use observations together with cloud-resolving models (CRMs). CRMs use more sophisticated and realistic representations of cloud microphysical processes, and they can reasonably well resolve the time evolution, structure, and life cycles of clouds and cloud systems (with sizes ranging from about 2-200 km). CRMs also allow for explicit interaction between clouds, outgoing longwave (cooling) and incoming solar (heating) radiation, and ocean and land surface processes. Observations are required to initialize CRMs and to validate their results. This paper provides a brief discussion and review of the main characteristics of CRMs as well as some of their major applications. These include the use of CRMs to improve our understanding of: (1) convective organization, (2) cloud temperature and water vapor budgets, and convective momentum transport, (3) diurnal variation of precipitation processes, (4) radiative-convective quasi-equilibrium states, (5) cloud-chemistry interaction, (6) aerosol-precipitation interaction, and (7) improving moist processes in large-scale models. In addition, current and future developments and applications of CRMs will be presented.

Tao, Wei-Kuo

2007-01-01

399

FIRE Arctic Clouds Experiment  

Microsoft Academic Search

An overview is given of the First ISCCP Regional Experiment Arctic Clouds Experiment that was conducted dur- ing April-July 1998. The principal goal of the field experiment was to gather the data needed to examine the impact of arctic clouds on the radiation exchange between the surface, atmosphere, and space, and to study how the surface influ- ences the evolution

J. A. Curry; P. V. Hobbs; M. D. King; D. A. Randall; P. Minnis; G. A. Isaac; J. O. Pinto; T. Uttal; A. Bucholtz; D. G. Cripe; H. Gerber; C. W. Fairall; T. J. Garrett; J. Hudson; J. M. Intrieri; C. Jakob; T. Jensen; P. Lawson; D. Marcotte; L. Nguyen; P. Pilewskie; A. Rangno; D. C. Rogers; K. B. Strawbridge; F. P. J. Valero; A. G. Williams; D. Wylie

2000-01-01

400

SoundCloudNav  

NSDL National Science Digital Library

For people who like to use SoundCloud to control their musical selections while working, this helpful plug-in will be a welcome find. SoundCloudNav will allow users to explore different tracks and manipulate them as they see fit. This version is compatible with all computers utilizing Google Chrome.

2012-05-10

401

Project Foggy Cloud I.  

National Technical Information Service (NTIS)

Foggy Cloud I was a series of experiments in observation, modification, and treatment of fog and stratus clouds conducted at or near the Arcata-Eureka airport, Humboldt County, Calif., from late March through mid-November 1968. A wide range of propsective...

E. A. Blomerth R. S. Clark H. E. Cronin J. R. Ennis R. L. Lininger

1970-01-01

402

Cloud Physics: The Basics  

NSDL National Science Digital Library

This website from the Oklahoma Weather Modification Program encourages students to initiate a debate on the controversy surrounding the issue of inducing or enhancing precipitation. The exercise describes the two basic tenets of cloud seeding: the Static Phase Hypothesis and the Dynamic Phase Hypothesis. Also provided are links to a weather and climate glossary and further information about clouds and precipitation.

Klatt, Michael L.

2008-01-14

403

OGLE-III. Magellanic Clouds stellar proper motions (Poleski+, 2012)  

NASA Astrophysics Data System (ADS)

The OGLE-III project observed the MCs between 2001 and 2009 with 1.3-m Warsaw telescope, which is situated at the Las Campanas Observatory, Chile. The observatory is operated by the Carnegie Institution for Science. (4 data files).

Poleski, R.; Soszynski, I.; Udalski, A.; Szymanski, M. K.; Kubiak, M.; Pietrzynski, G.; Wyrzykowski, L.; Ulaczyk, K.

2012-06-01

404

Dynamics and Cloud Structure of Neptune  

NASA Astrophysics Data System (ADS)

A 4-year gap in detailed observation of one of the most active planets in our solar system can be ended by our proposed multispectral WFPC2 imaging of Neptune over a period of 2 Neptune rotations. Our objectives are {1} mapping the two- dimensional distribution of Neptune's discrete cloud features and zonal bands with sufficiently dense longitudinal sampling to insure detection of any Great Dark Spot, or other major storm system, up to 35degrees N, {2} characterizing Neptune's circulation by tracking cloud motions during two densely sampled half-rotations that ensure reliable target identification, and {4} characterizing the vertical structure of clouds by imaging with filters that select varying amounts of Rayleigh scattering and methane absorption and by capturing their center-to-limb variations during intensely sampled feature transits. To enhance the characterization of cloud structure we will also propose coordinated groundbased IRTF and Keck observations, both using adaptive optics at near IR wavelengths that provide access to additional strong methane and hydrogen absorption bands. The proposed HST observations use the same filters as in 1996 and 1998, as well as additional filters, permitting detailed comparisons with previous observations.

Sromovsky, Lawrence

2002-07-01

405

Singularly perturbed vector fields  

NASA Astrophysics Data System (ADS)

A geometrically invariant concept of singularly perturbed systems of ordinary differential equations (singularly perturbed vector fields) is proposed in this paper. Singularly perturbed vector fields can be represented locally as singularly perturbed systems (for corresponding coordinate system choice. The paper focuses on possible ways of fast and slow directions/manifolds evaluations. A special algorithm for the evaluation is proposed. The algorithm is called as a global quasi-linearization procedure. A practical application of the proposed algorithm for numerical simulations is the main issue of the paper.

Bykov, V.; Goldfarb, I.; Gol'dshtein, V.

2006-12-01

406

Computing and Partitioning Cloud Feedbacks using Cloud Property Histograms  

NASA Astrophysics Data System (ADS)

In this study we propose a novel technique for computing cloud feedbacks using histograms of cloud fraction as joint functions of cloud top pressure and optical depth generated by the International Satellite Cloud Climatology Project (ISCCP) simulator, which was incorporated into the climate models that took part in the Cloud Feedback Model Intercomparison Project. We use a radiative transfer model to compute top of atmosphere (TOA) flux sensitivities to cloud fraction perturbations in each bin of the ISCCP simulator histogram, which we refer to as a cloud radiative kernel. Multiplying the cloud radiative kernel histogram with the histogram of actual cloud top fraction changes per unit of global warming simulated by each model produces an estimate of cloud feedback. Both the spatial structures and globally integrated values of cloud feedbacks computed in this manner agree remarkably well with those computed by adjusting the change in cloud radiative forcing for clear-sky effects as in Soden et al. (2008). The technique allows us to quantitatively partition cloud feedbacks into contributions from changes in cloud amount, height, and optical depth. We show that rising clouds are the dominant contributor to the positive LW cloud feedback, and that the extra-tropical contribution is approximately 70% as large as the tropical contribution. In the ensemble mean, the positive impact of rising clouds is 50% larger than the negative impact of reductions in cloud amount on LW cloud feedback, but the degree to which reductions in cloud fraction offset the effect of rising clouds varies considerably across models. In contrast, reductions in cloud fraction make a large and virtually unopposed positive contribution to SW cloud feedback, though the inter-model spread is greater than for any other individual feedback component. In general, models exhibiting greater reductions in subtropical marine boundary layer cloudiness tend to have larger positive SW cloud feedbacks, in agreement with previous studies. Overall reductions in cloud amount have twice as large an impact on SW fluxes as on LW fluxes such that the net cloud amount feedback is moderately positive, with no models analyzed here having a negative net cloud amount feedback. Finally, we find that although global mean cloud optical depth feedbacks are generally smaller than the other components, they are the dominant process at high latitudes, a perhaps surprising result considering one might expect increases in total cloud amount associated with the poleward shift of the storm track to dominate. This locally large negative optical depth feedback arises due to a combination of increased cloud water content and changes in phase from ice to liquid.

Zelinka, M. D.; Klein, S. A.; Hartmann, D. L.

2011-12-01

407

Image to Point Cloud Method of 3D-MODELING  

NASA Astrophysics Data System (ADS)

This article describes the method of constructing 3D models of objects (buildings, monuments) based on digital images and a point cloud obtained by terrestrial laser scanner. The first step is the automated determination of exterior orientation parameters of digital image. We have to find the corresponding points of the image and point cloud to provide this operation. Before the corresponding points searching quasi image of point cloud is generated. After that SIFT algorithm is applied to quasi image and real image. SIFT algorithm allows to find corresponding points. Exterior orientation parameters of image are calculated from corresponding points. The second step is construction of the vector object model. Vectorization is performed by operator of PC in an interactive mode using single image. Spatial coordinates of the model are calculated automatically by cloud points. In addition, there is automatic edge detection with interactive editing available. Edge detection is performed on point cloud and on image with subsequent identification of correct edges. Experimental studies of the method have demonstrated its efficiency in case of building facade modeling.

Chibunichev, A. G.; Galakhov, V. P.

2012-07-01

408

Prebiotic chemistry in clouds  

NASA Technical Reports Server (NTRS)

The chemical evolution hypothesis of Woese (1979), according to which prebiotic reactions occurred rapidly in droplets in giant atmospheric reflux columns was criticized by Scherer (1985). This paper proposes a mechanism for prebiotic chemistry in clouds that answers Scherer's concerns and supports Woese's hypothesis. According to this mechanism, rapid prebiotic chemical evolution was facilitated on the primordial earth by cycles of condensation and evaporation of cloud drops containing clay condensation nuclei and nonvolatile monomers. For example, amino acids supplied by, or synthesized during entry of meteorites, comets, and interplanetary dust, would have been scavenged by cloud drops containing clay condensation nuclei and would be polymerized within cloud systems during cycles of condensation, freezing, melting, and evaporation of cloud drops.

Oberbeck, Verne R.; Marshall, John; Shen, Thomas

1991-01-01

409

Cloud Model Bat Algorithm  

PubMed Central

Bat algorithm (BA) is a novel stochastic global optimization algorithm. Cloud model is an effective tool in transforming between qualitative concepts and their quantitative representation. Based on the bat echolocation mechanism and excellent characteristics of cloud model on uncertainty knowledge representation, a new cloud model bat algorithm (CBA) is proposed. This paper focuses on remodeling echolocation model based on living and preying characteristics of bats, utilizing the transformation theory of cloud model to depict the qualitative concept: “bats approach their prey.” Furthermore, Lévy flight mode and population information communication mechanism of bats are introduced to balance the advantage between exploration and exploitation. The simulation results show that the cloud model bat algorithm has good performance on functions optimization.

Zhou, Yongquan; Xie, Jian; Li, Liangliang; Ma, Mingzhi

2014-01-01

410

SMILES ice cloud products  

NASA Astrophysics Data System (ADS)

Upper tropospheric water vapor and clouds play an important role in Earth's climate, but knowledge of them, in particular diurnal variation in deep convective clouds, is limited. An essential variable to understand them is cloud ice water content. The Japanese Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on board the International Space Station (ISS) samples the atmosphere at different local times allowing the study of diurnal variability of atmospheric parameters. We describe a new ice cloud data set consisting of partial Ice Water Path and Ice Water Content. Preliminary comparisons with EOS-MLS, CloudSat-CPR and CALIOP-CALIPSO are presented. Then, the diurnal variation over land and over open ocean for partial ice water path is reported. Over land, a pronounced diurnal variation peaking strongly in the afternoon/early evening was found. Over the open ocean, little temporal dependence was encountered. This data set is publicly available for download in HDF5 format.

MilláN, L.; Read, W.; Kasai, Y.; Lambert, A.; Livesey, N.; Mendrok, J.; Sagawa, H.; Sano, T.; Shiotani, M.; Wu, D. L.

2013-06-01

411

Integrated video motion estimator with Retinex-like pre-processing for robust motion analysis in automotive scenarios: algorithmic and real-time architecture design  

Microsoft Academic Search

The paper presents a novel technique for robust motion analysis in real automotive scenarios based on integrated Retinex-like\\u000a pre-processing algorithm with block matching video motion estimator. Both algorithmic and real-time hardware design issues\\u000a are discussed. The benefits of the proposed technique are manifold: the entire system is more robust; the estimated motion\\u000a vectors are more reliable and less dependent on

Stefano Marsi; Sergio Saponara

2010-01-01

412

Precipitation growth in convective clouds. [hail  

NASA Technical Reports Server (NTRS)

Analytical solutions to the equations of both the growth and motion of hailstones in updrafts and of cloud water contents which vary linearly with height were used to investigate hail growth in a model cloud. A strong correlation was found between the hail embyro starting position and its trajectory and final size. A simple model of the evolution of particle size distribution by coalescence and spontaneous and binary disintegrations was formulated. Solutions for the mean mass of the distribution and the equilibrium size distribution were obtained for the case of constant collection kernel and disintegration parameters. Azimuthal scans of Doppler velocity at a number of elevation angles were used to calculate high resolution vertical profiles of particle speed and horizontal divergence (the vertical air velocity) in a region of widespread precipitation trailing a mid-latitude squall line.

Srivastava, R. C.

1981-01-01

413

Vector Addition with Integer Components  

NSDL National Science Digital Library

The Vector Addition with Integer Components model allows the user to split a vector into its components, and practice finding the magnitude and direction of a vector if you know the components. In this simulation the x and y components of each vector are all integers. In the "Find components" mode, you are given the magnitude and direction of the vector, and your goal is to find the x-component and the y-component of the vector. In the "Find magnitude and direction" mode, you are given the two components, and you need to find the magnitude and direction of the vector. The Vector Addition with Integer Components model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_components_integer.jar file will run the program if Java is installed.

Duffy, Andrew

2010-05-02

414

Massively parallel vector processing computer  

SciTech Connect

This patent describes a vector processing node for a computer of the type having a network of simultaneously operating vector processing nodes interconnected by bidirectional external busses for conveying parallel data words between the vector processing nodes. The vector processing node comprising: a bi-directional first bus for conveying parallel data words; a bi-directional second bus for conveying parallel data words; vector memory means connected for read and write access through the second bus for storing vectors comprising sequences of parallel data words conveyed on the second bus; vector processing means connected to the second bus for transmitting parallel data words to and receiving parallel data words from the vector memory means for generating output vectors comprising functions of input vectors stored in the vector memory means and for storing the output vectors in the vector memory means; and control means including a computer processor connected to the first bus, external port means controlled by the computer processor and connected between the first bus and the external busses, and local port means controlled by the computer processor connected between the first and second busses, for transmitting parallel data words to and receiving parallel data words from the first bus, the second bus, the external busses, and the vector memory.

Call, D.B.; Mudrow, A.; Johnson, R.C.; Bennion, R.F.

1990-01-02

415

On the fractal structure of molecular clouds  

NASA Astrophysics Data System (ADS)

We present a new method to analyze the structure of observed molecular cloud images which is the generalization of the Allan-variance method traditionally used in the stability and drift analysis of instrumentation and electronic devices. Applied to integrated intensity maps of two molecular cloud data sets, the method shows, together with an analysis of the phases of the cloud images, the observed structures to be well characterized by what is called a fractional Brownian motion (fBm)-structure in the context of fractal images. An fBm-structure results from a power law power spectrum of the image and a completely random distribution of the image phases. The power law index beta of the power spectrum derived for two sample clouds turns out to be close to 2.8. For an fBm-structure, the power spectral index beta determines other fractal measures such as the traditionally used box-counting dimension and the fractal dimension describing iso-intensity contours via their area-perimeter relation. We use a large data set covering observations at both large and small angular scales available for the Polaris Flare (Heithausen et al. \\cite{heithausen1998}) as the sample cloud to test these concepts. The area-perimeter dimension independently measured for this cloud %, d=1.6, is consistent with beta =2.8. The fBm-concept allows easy generation of realistic density representations for model clouds, to be used in radiative transfer and other cloud simulations. In a second step, we show that an ensemble of randomly positioned clumps with a power law mass spectrum dN/dM ~ M(-alpha ) gives an fBm-image. The power spectral index beta , the mass spectral index alpha , and the power law index of the mass-size relation M ~ L(gamma ) turn out to be related: beta =gamma (3-alpha ). The value of gamma derived via this relation and the independently determined values for alpha and beta is consistent with the value directly determined for the sample cloud. Our analysis confirms the recent suggestion by Elmegreen & Falgarone (\\cite{elmegreen1996}) that the mass distribution in molecular clouds is closely connected with their fractal structure, although the detailed form of the relation depends on the fractal structure model used. We discuss the implications of these results, obtained for the 2-dimensional observed images, for the underlying 3-dimensional cloud density structure. With some extrapolating assumptions on the 3-dim structure, they imply that the 3-dimensional structure is very much broken up, with the surface growing proportional to the volume. Clearly, additional information on the velocity structure, and in particular its physical link to the assumed fBm-density structure, is needed to describe the relevant properties of molecular cloud line shapes and line radiative transfer. The fBm-structure model allows an estimate on the observability of molecular cloud structure down to much smaller angular scales than presently reachable, e.g. with interferometric observations. It turns out that, due to the steepness of the image power spectrum, these will be extremely difficult. Only the next generation large mm-wave array will bring such observations into the regime of the feasible.

Stutzki, J.; Bensch, F.; Heithausen, A.; Ossenkopf, V.; Zielinsky, M.

1998-08-01

416

Structure from planar motion.  

PubMed

Planar motion is arguably the most dominant type of motion in surveillance videos. The constraints on motion lead to a simplified factorization method for structure from planar motion when using a stationary perspective camera. Compared with methods for general motion, our approach has two major advantages: a measurement matrix that fully exploits the motion constraints is formed such that the new measurement matrix has a rank of at most 3, instead of 4; the measurement matrix needs similar scalings, but the estimation of fundamental matrices or epipoles is not needed. Experimental results show that the algorithm is accurate and fairly robust to noise and inaccurate calibration. As the new measurement matrix is a nonlinear function of the observed variables, a different method is introduced to deal with the directional uncertainty in the observed variables. Differences and the dual relationship between planar motion and planar object are also clarified. Based on our method, a fully automated vehicle reconstruction system has been designed. PMID:17076405

Li, Jian; Chellappa, Rama

2006-11-01

417

Singular Vectors' Subtle Secrets  

ERIC Educational Resources Information Center

Social scientists use adjacency tables to discover influence networks within and among groups. Building on work by Moler and Morrison, we use ordered pairs from the components of the first and second singular vectors of adjacency matrices as tools to distinguish these groups and to identify particularly strong or weak individuals.

James, David; Lachance, Michael; Remski, Joan

2011-01-01

418

Vector potential methods  

NASA Technical Reports Server (NTRS)

Vector potential and related methods, for the simulation of both inviscid and viscous flows over aerodynamic configurations, are briefly reviewed. The advantages and disadvantages of several formulations are discussed and alternate strategies are recommended. Scalar potential, modified potential, alternate formulations of Euler equations, least-squares formulation, variational principles, iterative techniques and related methods, and viscous flow simulation are discussed.

Hafez, M.

1989-01-01

419

Techniques for Vector Quantization.  

National Technical Information Service (NTIS)

The second year of AFOSR support at the University of California, Santa Barbara has allowed us to make significant strides in exploring the potential of vector quantization for source coding. Some of this work is described in the attached list of referenc...

A. Gersho

1984-01-01

420

A New Approach to Using a Cloud-resolving Model to Study the Interactions Between Clouds, Precipitation and Aerosols  

NASA Technical Reports Server (NTRS)

Numerical cloud models, which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Because cloud-scale dynamics are treated explicitly, uncertainties stemming from convection that have to be parameterized in (hydrostatic) large-scale models are obviated, or at least mitigated, in cloud models. Global models will use the non-hydrostatic framework when their horizontal resolution becomes about 10 km, the theoretical limit for the hydrostatic approximation. This juncture will be reached one to two decades from now. Over the past generation, voluminous datasets on atmospheric convection have been accumulated from radar, instrumented aircraft, satellites, and rawinsonde measurements in field campaigns, enabling the detailed evaluation of models. Improved numerical methods have resulted in more accurate and efficient dynamical cores in models. Improvements have been made in the parameterizations of microphysical processes, radiation, boundary-layer effects, and turbulence; however, microphysical parameterizations remain a major source of uncertainty in all classes of atmospheric models. In recent years, exponentially increasing computer power has extended cloud-resolving-model integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as l0,OOO km in two-dimensions, and 1,OOO x 1,OOO km2 in three-dimensions. Cloud models now provide statistical information useful for developing more realistic physically-based parameterizations for climate models and numerical weather prediction models. A review of developments and applications of cloud models in the past, present and future will be presented in this talk. In particular, a new approach to using cloud-resolving models to study the interactions between clouds, precipitation and aerosols will be presented.

Tao, Wei-Kuo

2005-01-01

421

A New Approach to using a Cloud-Resolving Model to Study the Interactions between Clouds, Precipitation and Aerosols  

NASA Technical Reports Server (NTRS)

Numerical cloud models, which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Because cloud-scale dynamics are treated explicitly, uncertainties stemming from convection that have to be parameterized in (hydrostatic) large-scale models are obviated, or at least mitigated, in cloud models. Global models will use the non-hydrostatic framework when their horizontal resolution becomes about 10 km, the theoretical limit for the hydrostatic approximation. This juncture will be reached one to two decades from now. Over the past generation, voluminous datasets on atmospheric convection have been accumulated from radar, instrumented aircraft, satellites, and rawinsonde measurements in field campaigns, enabling the detailed evaluation of models. Improved numerical methods have resulted in more accurate and efficient dynamical cores in models. Improvements have been made in the parameterizations of microphysical processes, radiation, boundary-layer effects, and turbulence; however, microphysical parameterizations remain a major source of uncertainty in all classes of atmospheric models. In recent years, exponentially increasing computer power has extended cloud-resolving-model integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 square kilometers in three-dimensions. Cloud models now provide statistical information useful for developing more realistic physically-based parameterizations for climate models and numerical weather prediction models. A review of developments and applications of cloud models in the past, present and future will be presented in this talk. In particular, a new approach to using cloud-resolving models to study the interactions between clouds, precipitation and aerosols will be presented.

Tao, Wei-Kuo

2005-01-01

422

A New Approach to using a Cloud-Resolving Model to Study the Interactions between Clouds, Precipitation and Aerosols  

NASA Technical Reports Server (NTRS)

Numerical cloud models, which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Because cloud-scale dynamics are treated explicitly, uncertainties stemming from convection that have to be parameterized in (hydrostatic) large-scale models are obviated, or at least mitigated, in cloud models. Global models will use the non-hydrostatic framework when their horizontal resolution becomes about 10 kilometers, the theoretical limit for the hydrostatic approximation. This juncture will be reached one to two decades from now. Over the past generation, voluminous datasets on atmospheric convection have been accumulated from radar, instrumented aircraft, satellites, and rawinsonde measurements in field campaigns, enabling the detailed evaluation of models. Improved numerical methods have resulted in more accurate and efficient dynamical cores in models. Improvements have been made in the parameterizations of microphysical processes, radiation, boundary-layer effects, and turbulence; however, microphysical parameterizations remain a major source of uncertainty in all classes of atmospheric models. In recent years, exponentially increasing computer power has extended cloud-resolving-model integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-kilometer scales are resolved in horizontal domains as large as 10,000 kilometers in two dimensions, and 1,000 x 1,000 square kilometers in three-dimensions. Cloud models now provide statistical information useful for developing more realistic physically-based parameterizations for climate models and numerical weather prediction models. A review of developments and applications of cloud models in the past, present and future will be presented in this talk. In particular, a new approach to using cloud-resolving models to study the interactions between clouds, precipitation and aerosols will be presented.

Tao, Wei-Kuo

2005-01-01

423

Reconstructing tethered satellite skiprope motion by bandpass filtering magnetometer measurements  

NASA Technical Reports Server (NTRS)

This paper presents a unique scheme for reconstructing tethered satellite skiprope motion by ground processing satellite magnetometer measurements. The measurements are modified based on ground knowledge of the earth's magnetic field and passed through bandpass filters tuned to the skiprope frequency. Skiprope motion is then deduced from the steady-state outputs of the filters. Simulation results are presented which verify the scheme and show it to be robust. The concept is not just limited to tethered satellites. Indeed, it can be applied whenever there is a need to reconstruct the coning motion of a body about a known axis, given measurements of a known vector in body-fixed axes.

Polites, M. E.

1992-01-01

424

Motion-oriented video sequence interpolation using digital image warping  

NASA Astrophysics Data System (ADS)

We present a warping prediction scheme for motion compensated interpolation of image sequences by using the motion vectors transmitted to the decoder. In order to achieve the very low bit-rate, a method based on the Hermite form of the cubic polynomial curve segment for the reconstruction of skipped frame is developed so that the number of transmitted frames can be reduced. The principal idea is to reconstruct all picture elements at a certain time instant of their motion trajectory. Experimental results are presented to illustrate the subject quality of the reconstructed video frames.

Lee, Jun-Ye; Chau, Yawgeng A.; Jou, I.-Chang; Ju, Rong-Hauh

1995-04-01

425

Motion coherence affects human perception and pursuit similarly  

NASA Technical Reports Server (NTRS)

Pursuit and perception both require accurate information about the motion of objects. Recovering the motion of objects by integrating the motion of their components is a difficult visual task. Successful integration produces coherent global object motion, while a failure to integrate leaves the incoherent local motions of the components unlinked. We compared the ability of perception and pursuit to perform motion integration by measuring direction judgments and the concomitant eye-movement responses to line-figure parallelograms moving behind stationary rectangular apertures. The apertures were constructed such that only the line segments corresponding to the parallelogram's sides were visible; thus, recovering global motion required the integration of the local segment motion. We investigated several potential motion-integration rules by using stimuli with different object, vector-average, and line-segment terminator-motion directions. We used an oculometric decision rule to directly compare direction discrimination for pursuit and perception. For visible apertures, the percept was a coherent object, and both the pursuit and perceptual performance were close to the object-motion prediction. For invisible apertures, the percept was incoherently moving segments, and both the pursuit and perceptual performance were close to the terminator-motion prediction. Furthermore, both psychometric and oculometric direction thresholds were much higher for invisible apertures than for visible apertures. We constructed a model in which both perception and pursuit are driven by a shared motion-processing stage, with perception having an additional input from an independent static-processing stage. Model simulations were consistent with our perceptual and oculomotor data. Based on these results, we propose the use of pursuit as an objective and continuous measure of perceptual coherence. Our results support the view that pursuit and perception share a common motion-integration stage, perhaps within areas MT or MST.

Beutter, B. R.; Stone, L. S.

2000-01-01

426

Observed linkages between the northern annular mode/North Atlantic Oscillation, cloud incidence, and cloud radiative forcing  

NASA Astrophysics Data System (ADS)

The signature of the northern annular mode/North Atlantic Oscillation (NAM/NAO) in the vertical and horizontal distribution of tropospheric cloudiness is investigated in CloudSat and CALIPSO data from June 2006 to April 2011. During the Northern Hemisphere winter, the positive polarity of the NAM/NAO is marked by increases in zonally averaged cloud incidence north of ~60°N, decreases between ~25 and 50°N, and increases in the subtropics. The tripolar-like anomalies in cloud incidence associated with the NAM/NAO are largest over the North Atlantic Ocean basin/Middle East and are physically consistent with the NAM/NAO-related anomalies in vertical motion. Importantly, the NAM/NAO-related anomalies in tropospheric cloud incidence lead to significant top of atmosphere cloud radiative forcing anomalies that are comparable in amplitude to those associated with the NAM/NAO-related temperature anomalies. The results provide observational evidence that the most prominent pattern of Northern Hemisphere climate variability is significantly linked to variations in cloud radiative forcing. Implications for two-way feedback between extratropical dynamics and cloud radiative forcing are discussed.

Li, Ying; Thompson, David W. J.; Huang, Yi; Zhang, Minghong

2014-03-01

427

Clouds in GEOS-5  

NASA Technical Reports Server (NTRS)

The GEOS-5 atmospheric model is being developed as a weather-and-climate capable model. It must perform well in assimilation mode as well as in weather and climate simulations and forecasts and in coupled chemistry-climate simulations. In developing GEOS-5, attention has focused on the representation of moist processes. The moist physics package uses a single phase prognostic condensate and a prognostic cloud fraction. Two separate cloud types are distinguished by their source: "anvil" cloud originates in detraining convection, and large-scale cloud originates in a PDF-based condensation calculation. Ice and liquid phases for each cloud type are considered. Once created, condensate and fraction from the anvil and statistical cloud types experience the same loss processes: evaporation of condensate and fraction, auto-conversion of liquid or mixed phase condensate, sedimentation of frozen condensate, and accretion of condensate by falling precipitation. The convective parameterization scheme is the Relaxed Arakawa-Schubert, or RAS, scheme. Satellite data are used to evaluate the performance of the moist physics packages and help in their tuning. In addition, analysis of and comparisons to cloud-resolving models such as the Goddard Cumulus Ensemble model are used to help improve the PDFs used in the moist physics. The presentation will show some of our evaluations including precipitation diagnostics.

Bacmeister, Julio; Rienecker, Michele; Suarez, Max; Norris, Peter

2007-01-01

428

Community Cloud Computing  

NASA Astrophysics Data System (ADS)

Cloud Computing is rising fast, with its data centres growing at an unprecedented rate. However, this has come with concerns over privacy, efficiency at the expense of resilience, and environmental sustainability, because of the dependence on Cloud vendors such as Google, Amazon and Microsoft. Our response is an alternative model for the Cloud conceptualisation, providing a paradigm for Clouds in the community, utilising networked personal computers for liberation from the centralised vendor model. Community Cloud Computing (C3) offers an alternative architecture, created by combing the Cloud with paradigms from Grid Computing, principles from Digital Ecosystems, and sustainability from Green Computing, while remaining true to the original vision of the Internet. It is more technically challenging than Cloud Computing, having to deal with distributed computing issues, including heterogeneous nodes, varying quality of service, and additional security constraints. However, these are not insurmountable challenges, and with the need to retain control over our digital lives and the potential environmental consequences, it is a challenge we must pursue.

Marinos, Alexandros; Briscoe, Gerard

429

Nighttime Clouds in Martian Arctic (Accelerated Movie)  

NASA Technical Reports Server (NTRS)

An angry looking sky is captured in a movie clip consisting of 10 frames taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander.

The clip accelerates the motion. The images were take around 3 a.m. local solar time at the Phoenix site during Sol 95 (Aug. 30), the 95th Martian day since landing.

The swirling clouds may be moving generally in a westward direction over the lander.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

430

Planar motion, complex numbers, and falling leaves: An intriguing minilab  

Microsoft Academic Search

We stress the importance of a hands-on component in intermediate-level physics instruction. The place of model building in mechanics is illustrated by studying planar motion using complex numbers instead of vectors. A related minilab is described and analyzed.

Eugenia Etkina; Brian Holton; George Horton

1998-01-01

431

Model based human motion tracking using probability evolutionary algorithm  

Microsoft Academic Search

A novel evolutionary algorithm called probability evolutionary algorithm (PEA), and a method based on PEA for visual tracking of human motion are presented. PEA is inspired by estimation of distribution algorithms and quantum-inspired evolutionary algorithm, and it has a good balance between exploration and exploitation with very fast computation speed. The individual in PEA is encoded by the probability vector,

Shuhan Shen; Minglei Tong; Haolong Deng; Yuncai Liu; Xiaojun Wu; Kaoru Wakabayashi; Hideki Koike

2008-01-01

432

Perturbed motions of a rigid body close to regular precession  

Microsoft Academic Search

A study is made of the perturbed rotational motions of a rigid body close to regular precession in the Lagrange case. It is assumed that the angular velocity of the body is sufficiently high, and its axis is close to the dynamic symmetry axis of the body; it is also assumed that two projections of the perturbation moment vector onto

L. D. Akulenko; D. D. Leshchenko; F. L. Chernousko

1986-01-01

433

Motionally-induced electromagnetic fields generated by idealized ocean currents  

Microsoft Academic Search

Using the induction equation, we investigate the generation of electromagnetic fields by the motional electromagnetic induction due to ocean currents. In this paper, solutions are presented for a linear induction equation for the magnetic flux density vector which contains prescribed time-independent oc