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951.
Joseph A. Burns 《Icarus》1981,45(2):263-274
An extended photometric time series in the J and K bands of Neptune has a complex appearance which appears to require the simultaneous presence of three periodicities plus related harmonics in the (J-K) color. The most apparent of the fundamental periods is N1 = 17.73 hr. The two others are at N2 = 18.56 and N3 = 18.29 hr and may be the result of amplitude modulation of a previously reported period of 18.42 hr. We interpret the presence of multiple periodicity as indicating that distinct systems of zonal winds exist on the planet. We argue that these wind systems are probably confined to moderate or high latitudes on the basis of recent omages of the planet taken in a spectral region of strong CH4 absorption, and, by analogy to the zonal wind systems that exist in Jupiter's atmosphere, deduce a period of rotation for the body of the planet of 18.2 ± 0.4 hr. Zonal wind contrasts of up to 109 m sec?1 are implied in the atmosphere of Neptune by these observations. 相似文献
952.
The loss rate of fast electrons (with an energy much higher than the energy of the plasma electron thermal motion), when they
leave a magnetic cavern during a disturbance of the magnetic field azimuthal symmetry, is studied. The cases of point and
volume sources of fast particles have been considered. The plasma density in the cavern is supposed to be low, so that collisions
of fast electrons with plasma particles can be neglected. The effect of the electric field on particle motion is neglected
because it is assumed that the electric charge particles outgoing from the cavern is compensated by the counter current of
plasma conductivity electrons. The dependence of the loss value on the harmonic number and the amplitude of the cavern boundary
radius disturbance has been obtained. 相似文献
953.
D. D. Polozhentsev H. I. Potter J. A. Zelaya R. C. Zalles 《Astrophysics and Space Science》1991,177(1-2):215-218
In 1982 a Bolivia-USSR astronomical observatory began its activities near Tarija, Bolivia. Observations of 200 000 faint stars, 2822 bright stars (m6) and Halley's comet have been made with the expedition's astrograph. 相似文献
954.
R. A. Gulyaev 《Solar physics》1971,18(3):410-416
Cinematographic observations of the slitless flash spectrum near the D3 helium line were performed in Yurgamysh at the total solar eclipse of September 22, 1968. The intensity distribution of the D3 line was obtained with a height resolution of 44 km within the height interval between –3400 and +1700 km above the limb. The absorption line D3 on the disk near the limb was discovered. 相似文献
955.
Barbara J. Thompson Sarah E. Gibson Peter C. Schroeder David F. Webb Charles N. Arge Mario M. Bisi Giuliana de Toma Barbara A. Emery Antoinette B. Galvin Deborah A. Haber Bernard V. Jackson Elizabeth A. Jensen Robert J. Leamon Jiuhou Lei Periasamy K. Manoharan M. Leila Mays Patrick S. McIntosh Gordon J. D. Petrie Simon P. Plunkett Liying Qian Peter Riley Steven T. Suess Munetoshi Tokumaru Brian T. Welsch Thomas N. Woods 《Solar physics》2011,274(1-2):29-56
We present an overview of the data and models collected for the Whole Heliosphere Interval, an international campaign to study the three-dimensional solar?Cheliospheric?Cplanetary connected system near solar minimum. The data and models correspond to solar Carrington Rotation 2068 (20 March??C?16 April 2008) extending from below the solar photosphere, through interplanetary space, and down to Earth??s mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. The solar and inner heliospheric data showed structure consistent with the declining phase of the solar cycle. A closely spaced cluster of low-latitude active regions was responsible for an increased level of magnetic activity, while a highly warped current sheet dominated heliospheric structure. The geospace data revealed an unusually high level of activity, driven primarily by the periodic impingement of high-speed streams. The WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum. 相似文献
956.
A possible suture between an old craton in West Africa and the Arabian—Nubian shield is marked by a persistent zone of Phanerozoic weakness. This zone extends between the Nile and Niger deltas and passes through the Qattara embayment, along the Bahariya fault, through the Kufra basin, between the Tibesti and Jabal al Uwaynat massifs, through the Bahr el Ghazal and Lake Chad areas, and along the Benoue trough. 相似文献
957.
A. Baran R. Oreiro A. Pigulski F. Pérez Hernández A. Ulla M. D. Reed C. Rodríguez-López P. Moskalik S.-L. Kim W.-P. Chen R. Crowe M. Siwak L. Armendarez P. M. Binder K.-J. Choo A. Dye J. R. Eggen R. Garrido J. M. González Pérez S. L. Harms F.-Y. Huang D. Kozie H.-T. Lee J. MacDonald L. Fox Machado T. Monserrat J. Stevick S. Stewart D. Terry A.-Y. Zhou S. Zoa 《Monthly notices of the Royal Astronomical Society》2009,392(3):1092-1105
958.
This paper analyzed forest land use change in Trans-Boundary Laos–China Biodiversity Conservation Area which is called Namha National Biodiversity Conservation Areas (Namha NBCAs), with 1992 and 2002 TM (ETM). Based on GIS and statistical methods, the intensity, state index of land use change and transfer matrix were used to study spatio- temporal land use change in the region. The results showed that the area of forest land decreased greatly, also the area of bamboo and grassland decreased. The other way round, the area of unstocked forest, slash and burn and rice paddy land increased. As a whole, the intensity of forest land change was higher, but others were lower. From the transfer matrix, most of the forest land changed into unstocked forest and urban area, some to slash and burn. The grassland and bamboo were mainly transferred to forest and unstocked forest. The unstocked forest land mostly came from forest land and grassland. It was showed there were three main causes of the land use change namely: opium poppy cultivation, rubber plantation and also ecotourism activities and finally some policies were developed in order to address the land use change in the study areas. 相似文献
959.
960.
New results of the numerical modeling of the response of the outer atmosphere of the Sun to an impulsive heating are presented.
Features of the general process are considered both for powerful and weak solar flares. For the most powerful flares it is
necessary to take into account the effect of a saturation of the heat flow. Though for the most powerful solar flares the
saturation of a thermal flow is not such large, the influence of this effect is important for cases of powerful flares on
red dwarf stars, strongly limiting the input of the thermal energy downwards. The response of the atmosphere, which consists
of the chromosphere, the transition region and the corona, to weak heating is characterized by creation no one as usually
but two ascending coronal flows. The occurrence of the additional flow at coronal heights is caused by the inhomogeneous initial
heating of the outer atmosphere. Some types of soft X-ray and UV-jets can be associated with such additional flow.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献