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1.
This paper presents a method to calculate finite-time Lyapunov exponents (FTLEs) for experimental time series using numerical simulation to approximate the local Jacobian of the system at each time step. This combined numerical–experimental approach to the calculation of FTLE is applicable to any physical system which can be numerically approximated. By way of example, the method is applied to the problem of vessel capsize. 相似文献
2.
Evolution of the spin of Venus 总被引：1，自引：0，他引：1
Evolutionary sequences of the Venusian sidereal rotation period, and of its obliquity, under the action of solar gravitational torques on the body of the planet and on its atmosphere are here presented. They show that Venus initial configuration in the early history of the solar system may well have been of rotation period between 33 and 48 days with an angle of obliquity of about 170°. 相似文献
3.
Byron McKavanagh Bruce Boreham Kevin McCue Gary Gibson Jennifer Hafner George Klenowski 《Pure and Applied Geophysics》1995,144(1):39-57
Digital seismograms continuously recorded from 1988 to 1992 by two stations of the RESNOM seismic network in northern Baja
California, Mexico, were used to search for probable shear-wave anisotropic characteristics in the region of the Cerro Prieto
fault. Shear-wave splitting was identified in many of the three-component records analyzed. We measured the polarization direction
of the leadingS wave inside theS-wave window as well as the delay times between fast and slow phases on those records displaying shear-wave splitting. For
station CPX, which is nearest the Imperial Valley region to the north, the preferred polarization direction found in this
study (azimuth 180°±10°) coincides with the direction of the regional maximum compressive stress determined for the region.
This polarization direction can be interpreted in terms of the “Extensive Dilatancy Anisotropy” model as the effect of vertical
parallel aligned cracks. The preferred polarization direction measured at LMX, however, gives an azimuth of 45°±5°. Thus,
it appears that faults and fractures aligned oblique to the main tectonic trend have a greater influence on the anisotropic
characteristics of the crust south of Cerro Prieto volcano than that of the regional stress field. Time delays between slow
and fastS waves observed at CPX appear constant from 1988 to 1992 while delays measured at LMX for the same interval indicate a small
increase with time which cannot be attributed to azimuthal variations of paths. 相似文献
4.
An estimate is derived of the solar gravitational torque on the thermal atmospheric tide of Venus. The value obtained is compared with the computed torque on the body of the planet itself caused by viscous coupling between it and the superrotating atmosphere. The comparison suggests that the solar thermal torque and the viscous torque are effective in the maintenance of the four-day superrotation of the Venusian atmosphere.UMIST, Department of Physics 相似文献
5.
In the fall of 2009 the City of Satellite Beach (City), Florida, authorized a study designed to assess municipal vulnerability to rising sea level and facilitate discussion of potential adaptation strategies. The project is one of the first in Florida to seriously address the potential consequences of global sea level rise, now forecast to rise a meter or more by the year 2100. Results suggest the tipping point between relatively benign impacts and those that disrupt important elements of the municipal landscape is +?2 ft (0.6 m) above present. Seasonal flooding to an elevation of +?2 ft is forecast to begin around 2050 and thus the City has about 40 years to formulate and implement an adaptation plan. As an initial step, the Comprehensive Planning Advisory Board, a volunteer citizen committee serving as the City??s local planning authority, has recommended a series of updates and revisions to the City??s Comprehensive Plan. If approved by the City Council and Florida??s Department of Community Affairs, the amendments will provide a legal basis for implementing specific policies designed to reduce the City??s vulnerability to sea level rise. 相似文献
6.
C. Goyet R. Healy S.J. McCue D.M. Glover 《Deep Sea Research Part I: Oceanographic Research Papers》1997,44(12):1945-1955
We have combined the available total CO2, temperature, salinity and oxygen data from the TTO, SAVE and WOCE programs in the Atlantic Ocean to parameterize TCO2 below 500 m depth as a function of potential temperature, salinity and apparent oxygen utilization. We then use the Levitus data set of temperature, salinity and oxygen to compute the TCO2 profiles at the resolution of the Levitus data set on a 1° × 1° grid with a vertical resolution of 33 layers, more densely spaced in the upper 1500 m than below. Depending on the method used to interpolate the data (along isopycnals or vertically by station), the estimated random uncertainty of the computed TC02 values in the Atlantic Ocean throughout the water column below the wintertime mixed layer depth ranges from ± 7.1 μmol kg−1 to t 5.9 μmol kg−1. 相似文献
7.
Lydie Herfort Tawnya D. Peterson Fredrick G. Prahl Lee Ann McCue Joseph A. Needoba Byron C. Crump G. Curtis Roegner Victoria Campbell Peter Zuber 《Estuaries and Coasts》2012,35(3):878-891
The localized impact of blooms of the mixotrophic ciliate Myrionecta rubra in the Columbia River estuary during 2007–2010 was evaluated with biogeochemical, light microscopy, physiological, and molecular data. M. rubra affected surrounding estuarine nutrient cycles, as indicated by high and low concentrations of organic nutrients and inorganic nitrogen, respectively, associated with red waters. M. rubra blooms also altered the energy transfer pattern in patches of the estuarine water that contain the ciliate by creating areas characterized by high primary production and elevated levels of fresh autochthonous particulate organic matter, therefore shifting the trophic status in emergent red water areas of the estuary from net heterotrophy towards autotrophy. The pelagic estuarine bacterial community structure was unaffected by M. rubra abundance, but red waters of the ciliate do offer a possible link between autotrophic and heterotrophic processes since they were associated with elevated dissolved organic matter and showed a tendency for enhanced microbial secondary production. Taken together, these findings suggest that M. rubra red waters are biogeochemical hotspots of the Columbia River estuary. 相似文献
8.
During 1976 and 1977, 120 earthquakes occurred in South Australia which were large enough to be recorded by the University of Adelaide seismograph network, and subsequently located. Only four epicentres lie outside the recognised seismic zones of the Adelaide Geosyncline, Eyre Peninsula and the Southeast Zone; only four of the earthquakes had magnitudes (ML) greater than 4. Fault‐plane solutions for three of the events within the Geosyncline suggest a direction of principal stress which is a northeast southwest compression. 相似文献
9.
Global epicentre maps show that the majority of earthquakes are inter-plate, although moderate to large earthquakes do occur intra-plate, i.e. within the plates. The seismicity of the Australian continent is typical of intra-plate environments and a magnitude ML 6 earthquake has an average return period of about 5 years. Recordings of Australian intra-plate earthquakes are investigated here to characterise their frequency content, peak acceleration and duration.Due to lack of quality strong motion records of large intra-plate earthquakes at short distances, synthetic seismograms are commonly used for testing structural behaviour. An empirical Green's Function method (Geophys. Res. Lett., 5 (1978), 1–4; Proceedings of the Third International Microzonation Conference, Seattle, USA, vol. 1, (1982), pp. 447–458.) is chosen to simulate a large earthquake by summation in time of a number of smaller earthquakes or sub-events, each given a slightly different origin time to represent more realistically the propagation of a rupture along an assumed fault plane. In the first instance, recordings on rock of the magnitude ML 2.3 aftershock of the 29 December 1989 Newcastle earthquake were used as sub-events to simulate the main shock of magnitude ML 5.6. Validation studies for events recorded elsewhere in Australia are also considered.The response spectra of such synthetic events will be compared with the recommended spectra developed empirically from a statistical analysis of strong motion data for magnitude 5.4–6.5 intra-plate earthquakes recorded in other parts of the world and normalised to a peak ground velocity of 50 mm/s which is typical for a return period of 500 years in Australia (Australasian Structural Engineering Conference, Auckland, New Zealand, (1998), pp. 439–444.). Preliminary results from this comparison with the response spectra recommended for the Building Code of Australia show that the synthetic waveforms produced by this method are realistic and can be used to represent ground motion during typical Australian intra-plate earthquakes. 相似文献
10.
Although the largest earthquake since European settlement in South Australia occurred near Beachport in the Southeast in 1897, the recorded activity since then, even with the establishment of the University of Adelaide Seismograph Network and the Bureau of Mineral Resources station at Bellfield in the Victorian Grampians, has been small. Most of the known epicentres lie within the boundary of the Lower Cretaceous sediments marking the edge of the Otway Basin and there is some correlation with the belt of recent volcanism in the Mt Gambier‐Mt Burr region. 相似文献