The large coronal transient of 10 June 1973     

E. Hildner  J. T. Gosling  R. M. MacQueen  R. H. Munro  A. I. Poland  C. L. Ross 《Solar physics》1975,42(1):163-177

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The association of coronal mass ejection transients with other forms of solar activity   总被引：2，自引：0，他引：2  

R. H. Munro  J. T. Gosling  E. Hildner  R. M. MacQueen  A. I. Poland  C. L. Ross 《Solar physics》1979,61(1):201-215

Coronal mass ejection transients observed with the white light coronagraph on Skylab are found to be associated with several other forms of solar activity. There is a strong correlation between such mass ejection transients and chromospheric H activity, with three-quarters of the transients apparently originating in or near active regions. We infer that 40% of transients are associated with flares, 50% are associated with eruptive prominences solely (without flares), and more than 70% are associated with eruptive prominences or filament disappearances (with or without flares). Nine of ten flares which displayed apparent mass ejections of H-emitting material from the flare site could be associated with coronal transients. Within each class of activity, the more energetic events are more likely to be associated with an observable mass ejection.Now at Los Alamos Scientific Laboratories, Los Alamos, NM., U.S.A.The National Center for Atmospheric Research is sponsored by the National Science Foundation.  相似文献   

Past and future polar amplification of climate change: climate model intercomparisons and ice-core constraints   总被引：2，自引：2，他引：2  

V. Masson-Delmotte  M. Kageyama  P. Braconnot  S. Charbit  G. Krinner  C. Ritz  E. Guilyardi  J. Jouzel  A. Abe-Ouchi  M. Crucifix  R. M. Gladstone  C. D. Hewitt  A. Kitoh  A. N. LeGrande  O. Marti  U. Merkel  T. Motoi  R. Ohgaito  B. Otto-Bliesner  W. R. Peltier  I. Ross  P. J. Valdes  G. Vettoretti  S. L. Weber  F. Wolk  Y. YU 《Climate Dynamics》2006,26(5):513-529

Climate model simulations available from the PMIP1, PMIP2 and CMIP (IPCC-AR4) intercomparison projects for past and future climate change simulations are examined in terms of polar temperature changes in comparison to global temperature changes and with respect to pre-industrial reference simulations. For the mid-Holocene (MH, 6,000 years ago), the models are forced by changes in the Earth’s orbital parameters. The MH PMIP1 atmosphere-only simulations conducted with sea surface temperatures fixed to modern conditions show no MH consistent response for the poles, whereas the new PMIP2 coupled atmosphere–ocean climate models systematically simulate a significant MH warming both for Greenland (but smaller than ice-core based estimates) and Antarctica (consistent with the range of ice-core based range). In both PMIP1 and PMIP2, the MH annual mean changes in global temperature are negligible, consistent with the MH orbital forcing. The simulated last glacial maximum (LGM, 21,000 years ago) to pre-industrial change in global mean temperature ranges between 3 and 7°C in PMIP1 and PMIP2 model runs, similar to the range of temperature change expected from a quadrupling of atmospheric CO₂ concentrations in the CMIP simulations. Both LGM and future climate simulations are associated with a polar amplification of climate change. The range of glacial polar amplification in Greenland is strongly dependent on the ice sheet elevation changes prescribed to the climate models. All PMIP2 simulations systematically underestimate the reconstructed glacial–interglacial Greenland temperature change, while some of the simulations do capture the reconstructed glacial–interglacial Antarctic temperature change. Uncertainties in the prescribed central ice cap elevation cannot account for the temperature change underestimation by climate models. The variety of climate model sensitivities enables the exploration of the relative changes in polar temperature with respect to changes in global temperatures. Simulated changes of polar temperatures are strongly related to changes in simulated global temperatures for both future and LGM climates, confirming that ice-core-based reconstructions provide quantitative insights on global climate changes. An erratum to this article can be found at  相似文献   

A laboratory model of surface crust formation and disruption on lava flows through non-uniform channels     

Katharine V. Cashman  Ross C. Kerr  Ross W. Griffiths 《Bulletin of Volcanology》2006,68(7-8):753-770

Crust formation on basaltic lava flows dictates conditions of both flow cooling and emplacement. For this reason, flow histories are dramatically different depending on whether lava is transported through enclosed lava tubes or through open channels. Recent analog experiments in straight uniform channels (Griffiths et al. J Fluid Mech 496:33–62, 2003) have demonstrated that tube flow, dictated by a stationary surface crust, can be distinguished from a mobile crust regime, where a central solid crust is separated from channel walls by crust-free shear zones, by a simple dimensionless parameter ϑ, such that ϑ<25 produces tube flow and ϑ>25 describes the mobile crust regime. ϑ combines a previously determined parameter ψ, which describes the balance between the formation rate of surface solid and the shear strain that disrupts the solid crust, with the effects of thermal convection (described by the Rayleigh number Ra).Here we explore ways in which ϑ can be used to describe the behavior of basaltic lava channels. To do this we have extended the experimental approach to examine the effects of channel irregularities (expansions, contractions, sinuosity, and bottom roughness) on crust formation and disruption. We find that such changes affect local flow behavior and can thus change channel values of ϑ. For example, gradual widening of a channel results in a decrease in flow velocity that causes a decrease in ϑ and may allow a down-flow transition from the mobile crust to the tube regime. In contrast, narrowing of the channel causes an increase in flow velocity (increasing ϑ), thus inhibiting tube formation.We also quantify the fraction of surface covered by crust in the mobile crust regime. In shallow channels, variations in crust width (d _c) with channel width (W) are predicted to follow d _c∼W ^5/3. Analysis of channelized lava flows in Hawaii shows crustal coverage consistent with this theoretical result along gradually widening or narrowing channel reaches. An additional control on crustal coverage in both laboratory and basaltic flows is disruption of surface crust because of flow acceleration through constrictions, around bends, and over breaks in slope. Crustal breakage increases local rates of cooling and may cause local blockage of the channel, if crusts rotate and jam in narrow channel reaches. Together these observations illustrate the importance of both flow conditions and channel geometry on surface crust development and thus, by extension, on rates and mechanisms of flow cooling. Moreover, we note that this type of analysis could be easily extended through combined use of FLIR and LiDAR imaging to measure crustal coverage and channel geometry directly.Editorial responsibility: A. Harris  相似文献   

Solution of marble in the karst of the Pikikiruna range,Northwest Nelson,New Zealand   总被引：1，自引：0，他引：1  

Paul W. Williams  Ross K. Dowling 《地球表面变化过程与地形》1979,4(1):15-36

The paper reports the first research on karst solution processes and rates in New Zealand. The study area is an IHD representative basin in the northwest corner of the South Island in a mountain range consisting principally of Ordovician marble. The climate is sunny and warm (17°C) in summer and wet and cool (7°C) in winter. Average precipitation is 2,158 mm of which 525 mm evapotranspires, yielding a discharge of 51–75 l/s/km² in the river basin studied. Almost half of the catchment of 45.1 km² consists of karst which occurs mainly as a doline covered plateau at 600–900 m within which most drainage is subterranean. Water tracing is with fluorescein defined drainage patterns. Marble solution was established by estimating inputs, throughputs and outputs of water and dissolved calcium and magnesium in both autogenic and allogenic karst drainage systems. Particular attention was paid to estimating errors. Water samples for chemical analysis were taken irregularly for approximately one year, and a rating curve relating chemical load to discharge was established. The best estimate of solution loss from the basin yields a mean rate of 100 ±M24 m³/km²/a. Of this 80 per cent is derived from solution of marble by autogenic waters, mostly in the top 10–30 m of the marble outcrop. The remaining 20 per cent is accomplished by allogenic stream solution. Approximately 9.9 per cent of the dissolved calcium and magnesium load leaving the basin originates from non-karst rocks and 4.6 per cent is initially introduced by rainfall. River flows that are exceeded only 5 per cent of the time transport approximately 44 per cent of the annual dissolved load, while mean to low flows that occur for 75 per cent of the time transport 35 per cent of the annual solute load. This confirms the importance of low frequency-high magnitude events, but indicates also that in corrosion systems high frequency events of moderate to low magnitude can also accomplish significant work.  相似文献   

Radar measurements of wind and waves     

Klaus Hasselmann  W. Alpers  D. Barick  D. Crombie  C. Flachi  A. Fung  H. van Hutten  W. Jones  G. P. De Loor  B. Lipa  R. Long  D. Ross  C. Rufenach  W. Sandham  O. Shemdin  C. Teague  D. Trizna  G. Valenzuela  E. Walsh  F. Wentz  J. Wright 《Boundary-Layer Meteorology》1978,13(1-4):405-412

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On the relationship of radar backscatter to wind speed and fetch     

Duncan Ross  W. Linwood Jones 《Boundary-Layer Meteorology》1978,13(1-4):151-163

The physics of the interaction of electromagnetic waves with the ocean surface has been an active area of research for a number of years. We present here the results of satellite and aircraft experiments to investigate the ability of active microwave radars to infer surface wind speeds remotely. Data obtained from the recent National Aeronautics and Space Administration (NASA) Skylab experiment are compared with surface wind speeds measured by low-flying aircraft and ships-of-opportunity and found to give useful estimates of the oceanic wind field. We also investigate the influence of varying wave height on radar measurements of wind speed by measuring the backscattering cross-section for constant wind speed but variable wave conditions. We conclude that this effect is of little importance.  相似文献   

Major and trace element relationships in granodiorites and granites from Australia and South Africa     

Peter Kolbe  Stuart Ross Taylor 《Contributions to Mineralogy and Petrology》1966,12(2):202-222

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Copper-nickel-enriched ferromanganese nodules and associated crusts from the Bauer Basin,northwest Nazca plate   总被引：1，自引：0，他引：1  

Mitchell Lyle  Jack Dymond  G. Ross Heath 《Earth and Planetary Science Letters》1977,35(1):55-64

Analysis of a suite of ferromanganese nodules and crusts from the dredge Y73-3-22D in the Bauer Deep (13°40′S, 102°08′W) shows distinct differences between the nodules and crusts. Ultra-slow-scan X-ray diffraction shows that the nodules are more enriched in todorokite while the crusts are more enriched in δ MnO₂. Both have phillipsite and smectite as accessory minerals as well as minor amounts of apatite, barite, and quartz. Chemical analyses show that the nodules also have higher abundances of Mn, Ni, Cu, Zn, and Ba, while crusts are more enriched in Fe, Co, and Ca. We suggest that normal authigenic precipitation of ferromanganese oxyhydroxides from seawater controls the mineralogy and chemistry of the crusts, while nodule mineralogy and chemistry are governed by small-scale diagenetic reactions in the sediment. Todorokite may form because iron in the Fe-Mn oxyhydroxide material dispersed in the sediment reacts with amorphous silica to form iron-rich smectites. The remaining oxyhydroxide material recrystallizes as todorokite.  相似文献   

Stress dependence of recrystallized-grain and subgrain size in olivine   总被引：1，自引：0，他引：1  

John V. Ross  Hans G. Ave Lallemant  Neville L. Carter   《Tectonophysics》1980,70(1-2)

New experiments on Mt. Burnet dunite have been carried out to evaluate the effects of important physical parameters on recrystallized-grain size and subgrain size in olivine deforming under steady-state conditions. The experiments, done under both wet and dry conditions in a Griggs solid-pressure-medium apparatus, were conducted in constant strain rate, constant stress and stress relaxation modes at 10 kbar confining pressure, temperatures from 1000°C to 1300°C, strain rates from 10⁻⁴ to 10⁻⁸/sec and stress differences of from 0.5 to 10 kbar. For dunite deformed under wet conditions, recrystallized-grain size is slightly temperature-dependent but under dry conditions it is only stress-dependent with D = 137 σ^−1.27 for D in μm and σ in kbar. Subgrain sizes also depend only on stress; for the dry experiments d = 28 σ^−0.62 and for the wet ones d = 15 σ^−0.69. Subgrain sizes decrease with increasing stress but do not increase with decreasing stress and hence record only maximum stress levels. Recrystallized-grain sizes adjust to both increasing and decreasing stress levels, at minimal strains and times, and thus record the stress history. Because of this and of the inherent stability of recrystallized grains, this technique is regarded as more reliable than the subgrain size and free dislocation density and curvature methods for estimating stress magnitudes in tectonites having deformed in the steadystate.  相似文献