The use of solar faculae in studies of the sunspot cycle     

G. M. Brown  D. R. Evans 《Solar physics》1980,66(2):233-243

Comparison of the long-term variation of photospheric faculae areas with that of sunspots shows that studies of faculae provide both complementary and supplementary information on the behaviour of the solar cycle. Detailed studies of the development of sunspots with respect to faculae show that there is a high degree of order over much of a given cycle, but marked differences from cycle to cycle. Within a cycle the relationship between spot and faculae areas appears to be similar for the N and S solar hemispheres, and over the early stages of a cycle it is directly related to the magnitude of the maximum sunspot number subsequently attained in that cycle.This result may well have predictive applications, and formulae are given relating the peak sunspot number to simple parameters derived from this early developmental stage. Full application to the current cycle 21 is denied due to the cessation of the Greenwich daily photoheliographic measurements, but use of the cruder weekly data suggests a maximum smoothed sunspot number of 150 ± 22.The effects of the incompatibility of the spot and faculae data, in that faculae are unobservable over a large fraction of the solar disc and also do not always develop associated spots, have been examined in a detailed study of two cycles and shown not to vitiate the results.Now at NOAA, Environmental Data Service, NGSTDC, Boulder, Colo. 80302, U.S.A.  相似文献   

Saturn's satellites: Nuar-infrared spectrophotometry (0.6–2.5 μm) of the leading and trailing sides and compositional implications     

Roger N. Clark  Robert H. Brown  Pamela D. Owensby  Alex Steele 《Icarus》1984,58(2):265-281

Near-infrared spectra, 0.65–2.5 μm, are presented for Tethys, Dione, Rhea, Iapetus, and Hyperion. Water ice absorptions at 2.0, 1.5, and 1.25 μm are seen in the spectra of all five objects (except the 1.25-μm band was not detected in spectra of Hyperion) and the weak 1.04-μm ice absorption is detected on the leading and trailing sides of Rhea, and the trailing side of Dione. Upper limits to the 1.04-μm ice band depth are <0.3% for the leading side of Dione; <0.7% for the leading side of Iapetus, and the trailing side of Tethys; <1% on the trailing side of Iapetus; and <5% on the leading side of Tethys. The leading-trailing side ice band depth differences on Saturn's satellites are similar to those for the Galilean satellites, indicating possible surface modification by magnetospheric charged particle bombardment. Limits are determined for the amount of particulates, trapped gases, and amonium hydroxide on the surface. The surfaces of Saturn's satellites (except the dark side of Iapetus) are nearly pure water ice, with probably less than about 1 wt% particulate minerals. The ice could be clathrates with as much as a few weight percent trapped gases. The upper limit of amonium hydroxide depends on the spectral data precision and varies from ～ 1 wt% NH₃ for the leading side of Rhea to ～ 10 wt% NH₃ for Dione.  相似文献   

Martian craters from earth     

Rodger W. Gordon 《Icarus》1976,29(1):153-154

Martian craters were evidently observed and described by E. E. Barnard in 1892–1893 and by John E. Mellish in 1915.  相似文献   

Further studies of ionospheric and geomagnetic effects of sudden impulses     

R.R. Brown  V.M. Driatsky 《Planetary and Space Science》1973,21(11):1931-1935

From riometer records for the sudden impulse event of 4 February 1969, it is shown that ionospheric absorption accompanying a sudden impulse has the same type of latitude and longitude variations found for sudden commencement events. In addition, an examination of magnetograms at College, Alaska shows that some positive sudden impulses may trigger negative bays around local midnight, similar to the recent results for sudden commencements.  相似文献   

An analytical iterative algorithm for the prediction of special satellite orbit points with the Brouwer orbit theory     

Robert A. Gordon 《Celestial Mechanics and Dynamical Astronomy》1973,7(2):280-290

Employing a direct recursive algorithm in relation with analytical theories will yield a considerable saving in computer time, as opposed to simulating a point by point integration through repeated evaluations of the orbit theory. As a case in point, we shall compute the set of osculating orbiting elements corresponding to special events within the revolution of an artificial satellite.  相似文献   

Neutral Air Wind Influences deduced from Solar Cycle Changes in the F2 region Equatorial Anomaly     

G. M. Brown 《Geophysical Journal International》1973,33(1):93-101

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DO CENTRAL CITIES AND SUBURBS HAVE SIMILAR DIMENSIONS OF NEED?     

Marilyn A. Brown 《The Professional geographer》1980,32(4):400-411

This paper examines the proposition that United States suburbs are gradually acquiring many of the traits and problems traditionally associated with inner cities. An analysis of direct and surrogate measures of community development need indicates that in 1970 the average central city had a greater percapita need than the average Chicago suburb. However, the dimensions of need of central cities and suburbs are quite similar. Close associations between minority race, poverty, and female-headed families exist in both central cities and suburbs, as do high residual correlations between population decline, elderly populations, and low levels of crowding.  相似文献   

Temperature minimum heating in solar flares by resistive dissipation of Alfvén waves     

A. Gordon Emslie  P. A. Sturrock 《Solar physics》1982,80(1):99-112

We examine the possibility that the strong heating produced at temperature-minimum levels during solar flares is due to resistive dissipation of Alfvén waves generated by the primary energy release process in the corona. It is shown how, for suitable parameters, these waves can carry their energy essentially undamped into the temperature-minimum layers and can then produce a degree of heating consistent with observations.Also Department of Applied Physics, Stanford University.  相似文献   

Delimitation of offshore areas: Hard labour and bitter fruits at UNCLOS III     

E.D. Brown 《Marine Policy》1981,5(3):172-184

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Development of airborne oil thickness measurements     

Brown CE  Fingas MF 《Marine pollution bulletin》2003,47(9-12):485-492

A laboratory sensor has now been developed to measure the absolute thickness of oil on water slicks. This prototype oil slick thickness measurement system is known as the laser-ultrasonic remote sensing of oil thickness (LURSOT) sensor. This laser opto-acoustic sensor is the initial step in the ultimate goal of providing an airborne sensor with the ability to remotely measure oil-on-water slick thickness. The LURSOT sensor employs three lasers to produce and measure the time-of-flight of ultrasonic waves in oil and hence provide a direct measurement of oil slick thickness. The successful application of this technology to the measurement of oil slick thickness will benefit the scientific community as a whole by providing information about the dynamics of oil slick spreading and the spill responder by providing a measurement of the effectiveness of spill countermeasures such as dispersant application and in situ burning.

This paper will provide a review of early developments and discuss the current state-of-the-art in the field of oil slick thickness measurement.  相似文献