Theory of decametric radio emissions from Jupiter     

Ching S. Wu  Robert A. Smith  Jonas S. Zmuidzinas 《Icarus》1973,18(2):192-205

It is suggested that the Jovian decametric emissions (DAM) originate in a cyclotron instability of weakly relativistic electrons trapped in the Jovian magnetic field. The resulting radiation has a group velocity in the magnetosphheric plasma which may be of order 10²km/sec, and thus takes much more time to escape the magnetosphere than if the group velocity were at or near the speed of light. Therefore, the asymmetry of the Io phase with respect to sources east and west of the Earth-Jupiter line does not imply an asymmetric beaming of DAM; it is caused by the delay the waves experience in traversing the magnetosphere. The frequency drifts of milli- and decasecond bursts are also explained. It is found that the rotation of the magnetosphere can play an important role, since the observer views the propagation velocity of the waves as the sum of their group velocity and the velocity of the medium itself. The rotation velocity is in opposite directions, relative to the observer, for sources east and west of the Earth-Jupiter line; the resultant vector addition gives positive frequency drifts for decasecond bursts from the early and fourth sources, and negative drifts for bursts from the main and third sources. The negative drifts of millisecond bursts may be the result of large density gradients of plasma in a temporarily compressed magnetosphere.  相似文献   

Radio Astronomy Explorer (RAE)—I. Observations of terrestrial radio noise     

John R. Herman  Joseph A. Caruso  Robert G. Stone 《Planetary and Space Science》1973,21(3):443-461

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Annual General Meeting: February 5th, 1875     

Robert Etheridge 《Proceedings of the Geologists' Association. Geologists' Association》1875,4(4):205-212

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Faltenachsen in Überschiebungszonen     

Robert Balk 《International Journal of Earth Sciences》1953,41(1):90-103

English summary Near the eastern base of the Taconic Range, in extreme southwestern Vermont, a complex of chlorite slate is exposed in the position of the floor of a thrust along which a mass of dolomite-limestone has been pushed from the east against, and over, the slate. In addition to the common structure, exhibiting westward-overturned open folds, with slip cleavage dipping eastward, about parallel with the axial pianos, the slate displays a number of subsidiary shears or thrust zones having the same orientation as the principal thrust. In these zones, a strong lineation as well as axes of small folds plunge E—SE, parallel with the direction of propagation of the thrust blocks. The origin of the lineation and lamination is believed to be identical with that of corresponding structures in rolled steel and glass.However, the formation of folds with axes parallel to the direction of thrust requires an additional shear stress acting perpendicularly to the direction of thrusting. The inhomogeneous composition, strength, and mobility of the flooring rocks are pointed out, and it is suggested that unequal rates of yielding of local rock masses below the thrust block generated these supplementary stresses, producing slight movements of small masses sideways. That this is a reasonable explantation is shown by experiments on salt dome structure byEscher andKuenen, in which also axes of folds and lineation parallel with the direction of maximum forward propagation were produced.  相似文献   

The Transmission of Rayleigh Waves across an Ocean Floor with Two Surface Layers, Part II: Numerical     

Urs Hochstrasser  Robert Stoneley 《Geophysical Journal International》1937,4(S1):197-201

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On the geology of south-eastern Kincardineshire     

Robert Campbell 《Proceedings of the Geologists' Association. Geologists' Association》1912,23(5):295-298

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Geröllführende Schiefer und andere Trümmergesteine aus der Zentralzone der Ostalpen     

Schwinner  Robert 《International Journal of Earth Sciences》1929,20(3):211-244

Ohne Zusammenfassung  相似文献   

Value-added Impact of Geostationary Hyperspectral Infrared Sounders on Local Severe Storm Forecasts——via a Quick Regional OSSE     

Zhenglong LI  Jun LI  Pei WANG  Agnes LIM  Jinlong LI  Timothy J.SCHMIT  Robert ATLAS  Sid-Ahmed BOUKABARA  Ross N.HOFFMAN 《大气科学进展》2018,35(10):1217-1230

Accurate atmospheric temperature and moisture information with high temporal/spatial resolutions are two of the key parameters needed in regional numerical weather prediction(NWP) models to reliably predict high-impact weather events such as local severe storms(LSSs). High spectral resolution or hyperspectral infrared(HIR) sounders from geostationary orbit(GEO) provide an unprecedented source of near time-continuous, three-dimensional information on the dynamic and thermodynamic atmospheric fields—an important benefit for nowcasting and NWP-based forecasting. In order to demonstrate the value of GEO HIR sounder radiances on LSS forecasts, a quick regional OSSE(Observing System Simulation Experiment)framework has been developed, including high-resolution nature run generation, synthetic observation simulation and validation, and impact study on LSS forecasts. Results show that, on top of the existing LEO(low earth orbit) sounders, a GEO HIR sounder may provide value-added impact [a reduction of 3.56% in normalized root-mean-square difference(RMSD)] on LSS forecasts due to large spatial coverage and high temporal resolution, even though the data are assimilated every 6 h with a thinning of 60 km. Additionally, more frequent assimilations and smaller thinning distances allow more observations to be assimilated, and may further increase the positive impact from a GEO HIR sounder. On the other hand, with denser and more frequent observations assimilated, it becomes more difficult to handle the spatial error correlation in observations and gravity waves due to the limitations of current assimilation and forecast systems(such as a static background error covariance). The peak reduction of 4.6% in normalized RMSD is found when observations are assimilated every 3 h with a thinning distance of 30 km.  相似文献   

Optimal international technology cooperation for the low-carbon transformation     

Anselm Schultes  Marian Leimbach  Gunnar Luderer  Robert C. Pietzcker  Lavinia Baumstark  Nico Bauer 《Climate Policy》2018,18(9):1165-1176

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GIS diffusion in Uganda     

Sami Eria  Robert B. McMaster 《International journal of geographical information science》2017,31(5):884-906

Despite myriad studies having been carried out on the diffusion of geographical information systems (GIS) technology, only a limited number have been done within the context of developing countries. This paper addresses the research question, how did the diffusion of GIS technology occur in Uganda? Mixed methods were used for data collection, and analysis was performed using a theoretical framework called the diffusion of innovations (DOI). The results of the study showed that the adoption of GIS by institutions in Uganda occurred in a classic diffusion pattern consistent with diffusion theory. Adoption of GIS was promoted by its relative advantage over, and compatibility with, existing technologies. It was characterized by both heterophilous and homophilous communication channels, and influenced by change agents and champions. Its rate of adoption followed an S-shaped diffusion curve, and was hampered by bureaucracy, and patronage-based societal norms. This study makes a contribution to literature on GIS diffusion in developing countries.  相似文献