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1.
Kirk D. Borne 《Earth Science Informatics》2010,3(1-2):5-17
The growth of data volumes in science is reaching epidemic proportions. Consequently, the status of data-oriented science as a research methodology needs to be elevated to that of the more established scientific approaches of experimentation, theoretical modeling, and simulation. Data-oriented scientific discovery is sometimes referred to as the new science of X-Informatics, where X refers to any science (e.g., Bio-, Geo-, Astro-) and informatics refers to the discipline of organizing, describing, accessing, integrating, mining, and analyzing diverse data resources for scientific discovery. Many scientific disciplines are developing formal sub-disciplines that are information-rich and data-based, to such an extent that these are now stand-alone research and academic programs recognized on their own merits. These disciplines include bioinformatics and geoinformatics, and will soon include astroinformatics. We introduce Astroinformatics, the new data-oriented approach to 21st century astronomy research and education. In astronomy, petascale sky surveys will soon challenge our traditional research approaches and will radically transform how we train the next generation of astronomers, whose experiences with data are now increasingly more virtual (through online databases) than physical (through trips to mountaintop observatories). We describe Astroinformatics as a rigorous approach to these challenges. We also describe initiatives in science education (not only in astronomy) through which students are trained to access large distributed data repositories, to conduct meaningful scientific inquiries into the data, to mine and analyze the data, and to make data-driven scientific discoveries. These are essential skills for all 21st century scientists, particularly in astronomy as major new multi-wavelength sky surveys (that produce petascale databases and image archives) and grand-scale simulations (that generate enormous outputs for model universes, such as the Millennium Simulation) become core research components for a significant fraction of astronomical researchers. 相似文献
2.
J.-F. Miao D. Chen K. Wyser K. Borne J. Lindgren M. K. S. Strandevall S. Thorsson C. Achberger E. Almkvist 《Meteorology and Atmospheric Physics》2008,99(1-2):77-103
Summary The performance of MM5 mesoscale model (Version 3.6.3) using different planetary boundary layer (PBL) and land surface model
(LSM) parameterizations is evaluated and compared using high temporal and spatial resolution G?TE2001 campaign data at local
scale (a few kilometers) over the Greater G?teborg area along the Swedish west coast during 7–20 May 2001. The focus is on
impact of PBL and LSM parameterizations on simulated meteorological variables important for air quality applications such
as global radiation, diurnal cycle of near-surface air temperature and wind, diurnal cycle intensity, near-surface vertical
temperature gradient, nocturnal temperature inversion, boundary layer height, and low-level jet (LLJ). The model performance
for daytime and nighttime and under different weather conditions is also discussed. The purpose is to examine the performance
of the model using different PBL and LSM parameterizations at local scale in this area for its potential applications in air
quality modeling. The results indicate that the influence of PBL and LSM parameterizations on simulated global radiation,
diurnal cycle of near-surface air temperature and wind speed, diurnal cycle intensity, vertical temperature gradient, nocturnal
temperature inversion and PBL heights, which are critical parameters for air quality applications, is evident. Moreover, the
intensity and location of LLJ are simulated well by all schemes, but there also exist some differences between simulated results
by using different PBL and LSM schemes. Therefore, the choice of PBL and LSM parameterizations is important for MM5 applications
to air quality studies.
Correspondence: Junfeng Miao, Department of Earth Sciences, G?teborg University, P.O. Box 460, 405 30 G?teborg, Sweden 相似文献
3.
Résumé Un modèle bidimensionnel dans le sens vertical est utilisé afin d'étudier et de simuler la circulation marine engendrée par la marée dans l'estuaire du Saint‐Laurent. A partir d'une schématisation de l'Estuaire et de conditions en niveaux d'eau et salinités aux extrémités aval et amont du domaine d'étude, ce modèle génère la répartition des hauteurs d'eau et les distributions longitudinales et verticales de vitesses et salinités. Les résultats permettent alors de déduire les circulations instantanées obtenues aux différentes heures de la marée. Celles‐ci mettent en évidence des phénomènes physiques caractéristiques de l'estuaire du Saint‐Laurent et qui ont été plusieurs fois observés. Parmi ceux‐ci, les processus les plus importants concernent les marées internes, la remontée d'eau profonde et les effets des gradients horizontaux de salinités sur les profils verticaux de vitesse. 相似文献
4.
5.
We present the results of our study of two collisions of binary elliptical galaxies, NGC 4782/4783 and NGC 2672/2673. Each pair has a high relative velocity (>500 km s–1 along the line-of-sight) but the two pairs differ in mass ratio (1 for the first pair, and 10 for the second). CCD images and velocities obtained from digital spectra are used to constrain simulations of the galaxy collisions. Once a solution has been found and its uniqueness verified, we derive the binary orbital elements, the orientation of the orbit in the sky, the time since pericenter, and the dynamical mass of the pair. This method provides a quantitative determination of galaxy masses on the scale of the binary separations free from uncertainties due to projection effects. We also derive accurate timing of the collision and information about the fate of the pairs (merger/escape). Among our conclusions, we find that the dumb-bell galaxy NGC 4782/4783 isnot a supermassive galaxy as claimed from the high relative velocity and the high central dispersions, but has a moderateM/L
B10. Its trajectory has been changed from hyperbolic to elliptical as a result of energy lost during the collision. NGC 2672/2673 provides an interesting example of how the collision probes the internal structure and dynamics of a galaxy. It also has a moderateM/L
B7.Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Inc., for the National Aeronautics and Space Administration, MA, U.S.A.Kitt Peak National Observatory, National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation, AR, U.S.A. 相似文献
6.
We present the current capabilities of a software tool to automatically detect coronal mass ejections (CMEs) based on time
series of coronagraph images: the solar eruptive event detection system (SEEDS). The software developed consists of several
modules: preprocessing, detection, tracking, and event cataloging. The detection algorithm is based on a 2D to 1D projection
method, where CMEs are assumed to be bright regions moving radially outward as observed in a running-difference time series.
The height, velocity, and acceleration of the CME are automatically determined. A threshold-segmentation technique is applied
to the individual detections to automatically extract an approximate shape of the CME leading edge. We have applied this method
to a 12-month period of continuous coronagraph images sequence taken at a 20-minute cadence by the Large Angle and Spectrometric
Coronagraph (LASCO) instrument (using the C2 instrument only) onboard the Solar and Heliospheric Observatory (SOHO) spacecraft. Our automated method, with a high computational efficiency, successfully detected about 75% of the CMEs
listed in the CDAW CME catalog, which was created by using human visual inspection. Furthermore, the tool picked up about
100% more small-size or anomalous transient coronagraph events that were ignored by human visual inspection. The output of
the software is made available online at . The parameters of scientific importance extracted by the software package are the position angle, angular width, velocity,
peak, and average brightness. Other parameters could easily be added if needed. The identification of CMEs is known to be
somewhat subjective. As our system is further developed, we expect to make the process significantly more objective. 相似文献
7.
Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies. 相似文献
8.
We present preliminary results of our programme aimed at the study of asample of ULIRGs on the basis of two-dimensional (integral field)optical spectroscopy and multi-frequency high spatial resolution HSTimaging. In particular, we show here results on Mrk 273 and IRAS 12112+0305recently obtained with the INTEGRAL system at the 4.2 m WHT. Abrief comparison with the HST images is also made. 相似文献
9.
D. Farrah M. Rowan-Robinson S. Oliver S. Serjeant K. Borne A. Lawrence R.A. Lucas H. Bushouse L. Colina 《Monthly notices of the Royal Astronomical Society》2001,326(4):1333-1352
We present HST WFPC2 V -band imaging for 23 ultraluminous infrared galaxies (ULIRGs) taken from the QDOT redshift survey. The fraction of sources observed to be interacting is 87 per cent. Most of the merging systems show a number of compact 'knots', whose colour and brightness differ substantially from their immediate surroundings. Colour maps for nine of the objects show a non-uniform colour structure. Features include blue regions located towards the centres of merging systems which are likely to be areas of enhanced star formation, and compact red regions which are likely to be dust shrouded starbursts or active galactic nuclei. The host galaxies of the quasi-stellar objects (QSOs) in the sample were found to be either interacting systems or ellipticals. Our data show no evidence that ULIRGs are a simple transition stage between galaxy mergers and QSOs. We propose an alternative model for ULIRGs based on the morphologies in our sample and previous N -body simulations. Under this model ULIRGs as a class are much more diverse than a simple transition between galaxy merger and QSO. The evolution of IR power source and merger morphology in ULIRGs is driven solely by the local environment and the morphologies of the merger progenitors. 相似文献
10.
C. Kumsap Corresponding author F. Borne D. Moss 《International journal of geographical information science》2013,27(6):723-744
The paper discusses an approach known as ‘distance‐decayed visibility’, implemented using GIS, to the composition of 3D scenes for static forest landscape visualization. The distance‐decay concept is employed to model a spatial interaction in terms of visibility between any observation points and vegetations visible from those points. The vegetation visibility is measured in level of detail where high visibility uses high level of detail and vice versa. The interaction is modelled mathematically using an exponential decay function. The point distribution of projected models on a 3D scene is calculated in GIS to assign an appropriate value of ‘visibility decay constant’ to relate the distance from the observation point to the vegetations with the level of detail of the vegetations in the function. The advantages of the technique as measured against the quantitative benchmarks of rendering time and the number of polygons computed are addressed. Although the forest landscape of the study area consists of a large number of vegetation models, the technique helps to model the relation of vegetation visibility and viewing distance so realistically that the technique yields the visual quality of the result 3D scene visually and statistically comparable to the finest resolution scene. 相似文献