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91.
92.
Sonya J. Larocque Bernard Hétu & Louise Filion 《Geografiska Annaler: Series A, Physical Geography》2001,83(4):191-201
Slushflows are rare phenomena in southeastern Canada. Here we report for the first time the occurrence of slushflows in a subalpine environment in eastern Canada (Mt. Albert, Gaspé Peninsula, Québec). Because nothing is known of their frequency- magnitude in the area, we reconstructed the chronology of slushflow events over the past century using dendrogeomorphic techniques based on impact scars, reaction wood and traumatic resin ducts. Slushflows contributed to the formation of a tongue-shaped accumulation of 17900 m2 at the outlet of a firstorder drainage basin. The slushflow boulder tongue was composed of heterogeneous-sized, angular and unoriented clasts, which are markedly different from the sediments of an adjacent alluvial fan. Although movements were initiated above the subalpine forest limit, slushflows induced forest fragmentation along the treed slope. Three slushflow events were identified over the past century, in 1925, 1964 and 1988, respectively, which indicate exceptional initiation conditions and considerable geomorphic activity of individual events. 相似文献
93.
Maxime Le Goff Bernard Henry Lucien Daly 《Physics of the Earth and Planetary Interiors》1992,70(3-4):201-204
A statistical method is proposed for the smoothing of polar wander paths and for giving their confidence limits by the mean of successive ellipses. The method is fully parametrical and is based on the relations between the inertia matrix and the parameters of the Fisher distribution, from which a bivariate form is deduced. An elementary tensorial calculation gives the parameters of the confidence ellipse around a vectorial weighted mean, for any unimodal set of vectors. This model can also be used for other statistical tests, wherever the rotational symmetry hypothesis is not consistent (i.e. the fold test). 相似文献
94.
Bernard Henry 《Physics of the Earth and Planetary Interiors》1992,70(3-4):214-218
We present a model that is applicable to the relatively frequent case of rocks in which the magnetic fabric is dominated by uniaxial paramagnetic minerals, and in which the deformation (pure shear) corresponds to the March-Fernandez model. Borradaile et al.'s procedure for the isolation of the magnetic fabric of monocrystals of anisotropic components allows us to obtain the magnetic properties equivalent to those of all the component minerals if they should be artificially aligned. In the case of real component minerals with similar shape parameters, χ (dependent on dimension ratio), these properties will correspond to those of a theoretical equivalent mineral. Therefore, finite strain and orientation tensors may be determined from magnetic fabric measurements of such polymineralic rocks. 相似文献
95.
The product spectra of gravity and barometric pressure in Europe 总被引:11,自引:0,他引:11
D. E. Smylie Jacques Hinderer Bernd Richter Bernard Ducarme 《Physics of the Earth and Planetary Interiors》1993,80(3-4):135-157
A total of 111 000 hourly values of gravity and barometric pressure from stations in Europe is analysed. The data consist of two sets of records from Brussels, an early set of 36 000 h length and a more recent set of 21 000 h length, a set of records from Bad Homburg of 24 000 h length, and a set of records from Strasbourg of 30 000 h length. All of the gravity measurements were made with similar superconducting instruments and the pressure data were recorded simultaneously at each superconducting gravimeter site. The four sets of records have different time bases, and to bring out common features and suppress individual station systematic errors, the product spectrum is introduced. Spectral density estimates are first computed for a common spectral window for each record, and the product spectrum is formed by multiplying individual spectral estimates across records. The cumulative distribution function is found for the product spectrum and confidence intervals are calculated from it by iteration. The product spectrum in gravity reveals a triplet of resonances in the subtidal band which are shown by an automated computer search to be uniquely associated with the translational modes of the solid inner core. The product spectrum in barometric pressure clearly reveals the first 10 solar heating tides in the atmosphere, but otherwise does not show common features with the gravity product spectrum. In particular, the triplet of resonances in the subtidal band of the gravity product spectrum do not show up in the product spectrum of barometric pressure, climinating the atmosphere as their source. 相似文献
96.
Using estimates of the masses of nearly 1000 CMEs observed by SOLWIND from Howardet al. (1985), we re-plot the numbers of CMEs as a function of CME mass on a log-linear plot. The plot is significant in that it shows a linear trend over more than a decade of CME masses. The plot indicates a simple form for the distribution of the CME masses and allows an easy determination of the total mass ejected into the solar wind in the form of CMEs. We find that approximately 16% of the solar wind at solar maximum can be comprised of CME mass. There is no indication that the numbers of low-mass CMEs increase in number above the trend set by the more massive ones. Specifically, there is no increase in the numbers of small CMEs such that the whole of the solar wind can be comprised of them. 相似文献
97.
As a consequence of the Taylor–Proudman balance, a balance between the pressure, Coriolis and buoyancy forces in the radial and latitudinal momentum equations (that is expected to be amply satisfied in the lower solar convection zone), the superadiabatic gradient is determined by the rotation law and by an unspecified function of r, say, S(r), where r is the radial coordinate. If the rotation law and S(r) are known, then the solution of the energy equation, performed in this paper in the framework of the ML formalism, leads to a knowledge of the Reynolds stresses, convective fluxes, and meridional motions. The ML-formalism is an extension of the mixing length theory to rotating convection zones, and the calculations also involve the azimuthal momentum equation, from which an expression for the meridional motions in terms of the Reynolds stresses can be derived. The meridional motions are expanded as U
r(r,)=P
2(cos)2(r)/r
2+P
4(cos)4(r)/r
2 +..., and a corresponding equation for U
(r,). Here is the polar angle, is the density, and P
2(cos), P
4(cos) are Legendre polynomials. A good approximation to the meridional motion is obtained by setting 4(r)=–H2(r) with H–1.6, a constant. The value of 2(r) is negative, i.e., the P
2 flow rises at the equator and sinks at the poles. For the value of H obtained in the numerical calculations, the meridional motions have a narrow countercell at the poles, and the convective flux has a relative maximum at the poles, a minimum at mid latitudes and a larger maximum at the equator. Both results are in agreement with the observations. 相似文献
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