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71.
The Scripps Orbit and Permanent Array Center (SOPAC) has completed development for the UNAVCO community of first-generation GPS Seamless Archive (GSAC) software. The GSAC is a virtual archive composed of an assembly of agencies and investigators exchanging information about their respective GPS-related data holdings in a well defined, cohesive manner. The superset of this published information is collected and ingested into centralized databases administered currently by two data brokers (Retailers), who make the data available to the public in a seamless manner. There are three user interfaces available: the interactive GSAC Wizard, a command-line Unix-style executable called gsac-client, and a front door HTTP service called the GSAC Retailer Service Interface. Each user interface provides access to the data collections of 6 different GPS archives (GSAC Wholesalers) in North America. Together these archives have published more than 2 million GPS data files pertaining to over 10,000 different geodetic monuments. These datasets are composed in large part of data collected by US scientists and their collaborators over the period 1986 to the present in Western North America and other tectonically active regions around the globe, as well as the holdings of two IGS global data centers. In this article, we describe how the three GSAC user interfaces provide the community a powerful set of tools for seamlessly mining information and collecting data files from a distributed network of GPS archives.The GPS Toolbox is a column dedicated to highlighting algorithms and source code utilized by GPS Engineers and scientists. If you have an interesting program or software package you would like to share with our readers, please pass it along; e-mail it to us at gps-toolbox@ngs.noaa.gov. To comment on any of the source code discussed here, or to download source code, visit our website at . This column is edited by Stephen Hilla, National Geodetic Survey, NOAA, Silver Spring, Maryland, and Mike Craymer, Geodetic Survey Division, Natural Resources Canada, Ottawa, Ontario, Canada. 相似文献
72.
SOPAC Web site (http://sopac.ucsd.edu) 总被引:1,自引:0,他引:1
73.
The variation in mycosporine‐like amino acid (MAA) concentration in the soft coral Heteroxenia fuscescens in relation to changes in ultraviolet radiation (UVR) regimes was investigated at the Gulf of Eilat, northern Red Sea. Solar radiation (300–700 nm) was measured for different depths and seasons. The UVR irradiance was measured to a depth of 25 m on the reef. The mean attenuation coefficient for UV‐B measured in winter was twofold that of the summer value. Separation of H. fuscescens extracts by reverse‐phase isocratic high‐performance liquid chromatography revealed a single MAA compound, palythine (λmax = 320 nm). Possible seasonal changes in MAAs in colonies of H. fuscescens along a depth gradient were examined on different dates. Palythine concentrations in the colonies were significantly higher in summer than in the other seasons particularly in shallow water. Possible changes in MAA content in colonies of H. fuscescens as a result of UVR protection, were determined by experiments conducted for periods of 1 week, 1 month and 3 months, at a depth of 5 m. In these experiments colonies were removed from the natural substrate and placed underwater, protected from UVR by a PVC filter. Significant differences between UV‐exposed and protected colonies of H. fuscescens were found only in the 3‐month experiment conducted during the summer. These findings demonstrate that UVR is an important environmental factor regulating MAA biosynthesis in the soft coral H. fuscescens. 相似文献
74.
Volcanic eruptions are usually preceded by measurable signals of growing unrest, the most evident of which are the increase in seismicity and ground deformation. It is also important to identify precursors of a possible renewal of the volcanic activity and to distinguish between an eruptive activity characterized by an intrusion (with the related destructive power) and a migration of magma stored in the main conduits. The 2005–2006 eruption at Mt. Augustine (Alaska, USA) is a good example of a massive migration of magmatic fluids from depth (about 1 km b.s.l.) under the effect of gas overpressure. The movements, recorded by High Rate GPS (HRGPS) data (15 s of sampling and processing rate) from the stations deployed on the volcano, define the dimensions and the characteristics of the shallow plumbing system. In this study, we propose a model of the different stages preceding the effusive phase (the ‘precursory phase’), where gas overpressure in the body of the volcano opens the terminal conduit. 相似文献
75.
Gottfried Grünthal Dietrich Stromeyer Kurt Wylegalla Rainer Kind Rutger Wahlström Xiaohui Yuan Günter Bock 《Journal of Seismology》2008,12(3):413-429
The area south and east of the Baltic Sea has very minor seismic activity. However, occasional events occur as illustrated
by four events in recent years, which are analysed in this study: near Wittenburg, Germany, on May 19, 2000, M
w = 3.1, near Rostock, Germany, on July 21, 2001, M
w = 3.4 and in the Kaliningrad area, Russia, two events on September 21, 2004 with M
w = 4.6 and 4.7. Locations, magnitudes (M
L and M
w) and focal mechanisms were determined for the two events in Germany. Synthetic modeling resulted in a well-confined focal
depth for the Kaliningrad events. The inversion of macroseismic observations provided simultaneous solutions of the location,
focal depth and epicentral intensity. The maximum horizontal compressive stress orientations obtained from focal mechanism
solutions, approximately N–S for the two German events and NNW–SSE for the Kaliningrad events, show a good agreement with
the regionally oriented crustal stress field. 相似文献
76.
77.
Stefan Gottlöber Ewa L. okas Anatoly Klypin Yehuda Hoffman 《Monthly notices of the Royal Astronomical Society》2003,344(3):715-724
Presented here are high spatial and spectral resolution Chandra X-ray observations of the famous interacting galaxy pair, the Mice, a system similar to, though less evolved than, the well-known Antennae galaxies. Previously unpublished ROSAT High Resolution Imager data of the system are also presented.
Starburst-driven galactic winds outflowing along the minor axis of both galaxies (but particularly the northern one) are observed, and spectral and spatial properties, and energetics are presented. That such a phenomenon can occur in such a rapidly evolving and turbulent system is surprising, and this is the first time that the very beginning – the onset, of starburst-driven hot gaseous outflow in a full-blown disc–disc merger has been seen.
Point-source emission is seen at the galaxy nuclei, and within the interaction-induced tidal tails. Further point-source emission is associated with the galactic bar in the southern system. A comparison of the source X-ray luminosity function and of the diffuse emission properties is made with the Antennae and other galaxies, and evidence of a more rapid evolution of the source population than the diffuse component is found. No evidence for variability is found between the Chandra and previous observations. 相似文献
Starburst-driven galactic winds outflowing along the minor axis of both galaxies (but particularly the northern one) are observed, and spectral and spatial properties, and energetics are presented. That such a phenomenon can occur in such a rapidly evolving and turbulent system is surprising, and this is the first time that the very beginning – the onset, of starburst-driven hot gaseous outflow in a full-blown disc–disc merger has been seen.
Point-source emission is seen at the galaxy nuclei, and within the interaction-induced tidal tails. Further point-source emission is associated with the galactic bar in the southern system. A comparison of the source X-ray luminosity function and of the diffuse emission properties is made with the Antennae and other galaxies, and evidence of a more rapid evolution of the source population than the diffuse component is found. No evidence for variability is found between the Chandra and previous observations. 相似文献
78.
J. M. Lamarre J. L. Puget F. Bouchet P. A. R. Ade A. Benoit J. P. Bernard J. Bock P. De Bernardis J. Charra F. Couchot J. Delabrouille G. Efstathiou M. Giard G. Guyot A. Lange B. Maffei A. Murphy F. Pajot M. Piat I. Ristorcelli D. Santos R. Sudiwala J. F. Sygnet J. P. Torre V. Yurchenko D. Yvon 《New Astronomy Reviews》2003,47(11-12):1017
The High Frequency Instrument (HFI) of Planck is the most sensitive CMB experiment ever planned. Statistical fluctuations (photon noise) of the CMB itself will be the major limitation to the sensitivity of the CMB channels. Higher frequency channels will measure galactic foregrounds. Together with the Low Frequency Instrument, this will make a unique tool to measure the full sky and to separate the various components of its spectrum. Measurement of the polarization of these various components will give a new picture of the CMB. In addition, HFI will provide the scientific community with new full sky maps of intensity and polarization at six frequencies, with unprecedented angular resolution and sensitivity. This paper describes the logics that prevailed to define the HFI and the performances expected from this instrument. It details several features of the HFI design that has not been published up to now. 相似文献
79.
The complementary mild-slope equation (CMSE) is a depth-integrated equation, which models refraction and diffraction of linear time-harmonic water waves. For 2D problems, it was shown to give better agreements with exact linear theory compared to other mild-slope (MS) type equations. However, no reference was given to 3D problems. In contrast to other MS-type models, the CMSE is derived in terms of a stream function vector rather than in terms of a velocity potential. For the 3D case, this complicates the governing equation and creates difficulties in formulating an adequate number of boundary conditions. In this paper, the CMSE is re-derived using Hamilton's principle from the Irrotational Green–Naghdi equations with a correction for the 3D case. A parabolic version of it is presented as well. The additional boundary conditions needed for 3D problems are constructed using the irrotationality condition. The CMSE is compared with an analytical solution and wave tank experiments for 3D problems. The results show very good agreement. 相似文献
80.