Lateral moisture flow beneath a sandy hillslope without an apparent impeding layer     

James T. McCord  Daniel B. Stephens 《水文研究》1987,1(3):225-238

Part of a small drainage basin on the Sevilleta National Wildlife Refuge (about 25 km north of Socorro, NM) was intensively instrumented with soil monitoring equipment to estimate natural ground-water recharge. Soil-moisture data were analysed with special attention to characterizing the influence of topography on the direction of vadose water flow paths in fine to medium aeolian sand. Moisture content data were obtained by the neutron scattering technique, and hydraulic head data were obtained using tensiometers. In addition, tracer experiments were conducted on a sandy hillslope to delineate the flow paths of vadose water. The results indicate that there is a strong lateral component to unsaturated flow on a hillslope, even in the absence of apparent sublayers of much lower permeability. Darcian calculations estimate the long-term, steady, deep flux beneath a concave location to be about 4 per cent of an assumed mean annual precipitation of 20 cm. The deep soil water flux downward varied by several orders of magnitude during the 17 month period of record.  相似文献   

La plate-forme continentale du portugal et les provinces adjacentes: Analyse géomorphologique     

Daniel Jean Stanley 《Geo-Marine Letters》1982,2(1-2):109-109

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Electromagnetic induction fields in the deep ocean north-east of Hawaii: implications for mantle conductivity and source fields     

Alan D. Chave  R. P. Von  Herzen K. A. Poehls †  C. S. Cox 《Geophysical Journal International》1981,66(2):379-406

Summary. We have analysed a thirty-six day recording of the natural electric and magnetic field variations obtained on the deep ocean floor north-east of Hawaii. The electromagnetic fields are dominated by tides which have an appreciable oceanic component, especially in the east electric and north magnetic components. The techniques of data analysis included singular value decomposition (SVD) to remove uncorrelated noise. There are three degrees of freedom in the data set for periods longer than five hours, indicating a correlation of the vertical magnetic field and the horizontal components, suggesting source field inhomogeneity. Tensor response functions were calculated using spectral band averaging with both SVD and least squares techniques and rotated to the principal direction. One diagonal component, determined mainly by the north electric and east magnetic fields, is not interpretable as a one-dimensional induction phenomenon. The other diagonal term of the response function indicates a rapid rise in conductivity to 0.05 mho m⁻¹ near 160 km. No decrease in conductivity below this depth is resolvable. Polarization analysis of the magnetic field indicates moving source fields with a wavelength near 5000 km. Model studies suggest that the two dimensionality in the response function may be caused by motion in the ionospheric current system.  相似文献   

Far-infrared brightness temperature of Saturn's disk and rings     

R.R. Daniel  S.K. Ghosh  K.V.K. Iyengar  T.N. Rengarajan  S.N. Tandon  R.P. Verma 《Icarus》1982,49(2):205-212

We present far-infrared observations of Saturn in the wavelength band 76–116 μm, using a balloon-borne 75-cm telescope launched on 10 December 1980 from Hyderabad, India, when B′, the Saturnicentric latitude of the Sun, was 4°.3. Normalizing with respect to Jupiter, we find the average brightness temperature of the disk-ring system to be 90 ± 3° K. Correcting for the contribution from rings using experimental information on the brightness temperature of rings at 20 μm, we find T_D, the brightness temperature of the disk, to be 96.9 ± 3.5° K. The systematic errors and the correction for the ring contribution are small for our observations. We, therefore, make use of our estimate of T_D and earlier observations of Saturn when contribution from the rings was large and find that for wavelengths greater than 50 μm, there is a small reduction in the ring brightness temperature as compared to that at 20 μm.  相似文献   

Palaeomagnetism of a sequence of Upper Palaeozoic-Lower Mesozoic red beds from Argentina     

Ana M. Sinito  Daniel A. Valencio  Juan F. Vilas 《Geophysical Journal International》1979,58(2):237-247

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A search for energetic neutrons emitted during solar flares     

R. R. Daniel  G. S. Gokhale  G. Joseph  P. J. Lavakare  B. S. Sekhon 《Solar physics》1969,10(2):465-471

On the basis of solar flare forecasts, balloon flights were made from Hyderabad, India (vertical geomagnetic threshold rigidity of 16.9 GV), to detect the possible emission of high energy neutrons during solar flares. The detector comprised of a central plastic scintillator, completely surrounded by an anticoincidence plastic scintillator shield. The instrument responds to neutrons of about 15–150 MeV and gamma rays of about 5–30 MeV with about the same efficiency. The detector was flown to an atmospheric depth of 25 g cm^-2 on February 26, 1969; while the balloon was at ceiling a flare of importance 2B and one of 1N occurred. No perceptible flare associated increase in the counting rate was observed. Using the observed counting rates, an upper limit of 1.2 × 10^-2 neutrons cm^-2 sec^-1 is obtained for the first time for a flare of importance 2B for neutrons of energy 15–150 MeV. The corresponding upper limit for gamma rays of energy 5–30 MeV is found to be 10^-2 photons cm^-2 sec^-1. The neutron flux limits are compared with the recent calculations of Lingenfelter.  相似文献   

La raie rouge de l'oxygene dans la lumiere du ciel nocturne     

Daniel Barbier 《Studia Geophysica et Geodaetica》1960,4(4):350-360

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Palaeomagnetism of Upper Precambrian rocks of the La Tinta Formation, Argentina     

Daniel A. Valencio  Ana M. Sinito  Juan F. Vilas 《Geophysical Journal International》1980,62(3):563-575

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The energy spectrum of cosmic ray electrons between 10 and 1000 GeV     

K. C. Anand  R. R. Daniel  S. A. Stephens 《Astrophysics and Space Science》1975,36(1):169-175

Measurements made by the Bombay Group on the fluxes of cosmic ray electrons in the energy range 10–1000 GeV have been compared with those of other workers in the same energy domain with a view to understand the present confused situation on the existing observations at these high energies. Such an analysis clearly brings out the current situation in its true perspective and highlights the care and emphasis to be placed on future experimentation in this important field.  相似文献   

Transit or occultation?     

Daniel M. Popper 《Astrophysics and Space Science》1976,45(2):391-396

Published discussions of photometric observations of VZ Hya and CM Lac disagree as to whether the deeper eclipses are transits or occultations. The evolutionary histories of these systems are critically dependent on a resolution of the disagreement. The luminosity ratio of the components of VZ Hya, inferred from spectrograms, shows unequivocally that the deeper eclipse is a transit. The case of CM Lac is less definitive. While the photometric observations favor primary minimum as a transit, the ratio of the radii is close to unity, and neither the spectrograms nor the photometry leads to an unequivocal result. Some confusion in notation appearing in a discussion of the components of EI Cep is noted. In each of the three cases the observational evidence favors a straightforward evolutionary interpretation in which the more massive star is the larger.  相似文献