The Alaskan shelf: Hydrographic,sedimentary and geochemical environment | G.D. Sharma, 1979. Springer-Verlag,Berlin, 498 pp., DM 59.00     

Robert E. Burns 《Earth》1982,18(1):80-81

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THE SUN BELT-SNOW BELT: A CASE OF SLOPPY REGIONALIZING     

Clyde E. Browning  Wil Gesler 《The Professional geographer》1979,31(1):66-74

The Sun Belt has become a part of the American vocabulary without a careful examination of its validity as a region. This analysis, using a variety of techniques and variables taken from the topics of federal involvement, economic well-being, and population change, concludes that the Sun Belt does not emerge as a distinct and homogeneous region. The Snow Belt would be better expressed as the Core (the old Manufacturing Belt).  相似文献   

“An oasis for us”: ‘in-between’ spaces of training for people with mental health problems in the Scottish Highlands     

Chris Philo  Hester Parr  Nicola Burns 《Geoforum》2005,36(6):778-791

Training and Guidance (TAG) units in the Scottish Highlands are sites that people with mental health problems can access for training and learning activities designed to prepare them for (re-)entry into the labour market. These units also perform other, perhaps more intangible, roles in assisting trainees to cope with their mental health problems, thereby offering a supportive setting with therapeutic dimensions (albeit one not explicitly configured as delivering therapy). In this paper we explore the ‘in-between’ quality of the TAG units as spaces that might be said to possess dual economic and social roles. Using primarily qualitative evidence, we investigate both sets of roles, debating the extent to which the economic and social imperatives complement or contradict one another. The paper contributes to critical commentary on how ‘workfare’ initiatives articulate with the experiences and concerns of disabled trainees, the novelty arising in part from centralising the material spaces at the heart of such initiatives.  相似文献   

Stable isotope study of cave percolation waters in subtropical Brazil: Implications for paleoclimate inferences from speleothems     

Francisco W. Cruz  Jr.  Ivo Karmann  Oduvaldo Viana  Jr.  Stephen J. Burns  Jos A. Ferrari  Mathias Vuille  Alcides N. Sial  Marcelo Z. Moreira 《Chemical Geology》2005,220(3-4):245-262

We analyze the interannual monthly variability of oxygen isotope ratios in data from IAEA stations along the Atlantic coast of South America between 23° and 34° S to evaluate the influence of parameters such as temperature, rainfall amount and moisture source contribution on meteoric water recharging two karst systems in subtropical Brazil. In addition, a 2 year monitoring program performed on soil and cave drip and rimstone pool waters from sampling sites with contrasting discharge values and located at 100 and 300 m below the surface in the Santana Cave System (24°31′ S; 48°43′ W), is used to test the influence of hydrologic and geologic features on the temporal variations of seepage water δ¹⁸O.

Interannual monthly variations in δ¹⁸O of rainfall reflect primarily regional changes in moisture source contribution related to seasonal shifts in atmospheric circulation from a more monsoonal regime in summer (negative values of δ¹⁸O) to a more extratropical regime in winter (positive values of δ¹⁸O). Variations in groundwater δ¹⁸O indicate that the climatic signal of recent rainfall events is rapidly transmitted through the relatively deep karst aquifer to the cave drip waters, regardless of location of collection in the cave. In addition, the data also suggest that water replenishment in the system is triggered by the increase in hydraulic head during periods when recharge exceeds the storage capacity of the soil and epikarst reservoirs. Significant perturbations in the groundwater composition, characterized by more positive values of δ¹⁸O, are probably connected to an increased Atlantic moisture contribution associated with extratropical precipitation. This implies that the δ¹⁸O of speleothems from caves in this region may be a suitable proxy for studying tropical–extratropical interactions over South America, a feature that is intrinsically related to the global atmospheric circulation.  相似文献   

Shallow Drainage Flows   总被引：1，自引：1，他引：0  

L. Mahrt  Dean Vickers  Reina Nakamura  M. R. Soler  Jielun Sun  Sean Burns  D.H. Lenschow 《Boundary-Layer Meteorology》2001,101(2):243-260

Two-dimensional sonic anemometers and slowresponse thermistors were deployedacross a shallow gully during CASES99. Weak gully flow of a few tenths of m s^-1 anda depth of a few metres develops in the earlyevening on most nights with clear skies.Flow down the gully developed sometimes evenwhen the opposing ambient wind exceeded10 m s^-1 at the top of the60–m tower. Cold air drainage fromlarger-scale slopes flows over the top ofthe colder gully flow. The gully flowand other drainage flows are generally eliminated in the middle of the night in conjunctionwith flow acceleration abovethe surface inversion layer and downwardmixing of warmer air and highermomentum. As the flow decelerates later inthe night, the gully flow may re-form.The thin drainage flows decouple standard observational levels of3–10 m from the surface.Under such common conditions, eddy correlationflux measurements cannot be used toestimate surface fluxes nor even detect thethin gully and drainage flows. The gentlegully system in this field program is typical ofmuch of the Earths land surface.  相似文献   

Argon auroral emissions     

G. B. Burns  P. F. B. Williams  R. P. Lowe  W. J. R. French  P. A. Greet  D. P. Monselesan 《Journal of Atmospheric and Solar》2002,64(18)

Argon is the third most abundant constituent of the atmosphere, but has not been previously detected by any ground-based optical remote sensing method. We report observation of argon emissions at λ840.82 and λ842.46 nm during intense aurora. These are most likely excited by direct electron impact. The maximum argon intensity observed is 270 R. Argon is the fifth elemental emission conclusively observed in geo-aurora, joining N, O, H and He.  相似文献   

An example of a highly bioturbated,storm‐influenced shoreface deposit: Upper Jurassic Ula Formation,Norwegian North Sea     

Greg M. Baniak  Murray K. Gingras  Beverly A. Burns  S. George Pemberton 《Sedimentology》2014,61(5):1261-1285

Integrated ichnological and sedimentological analyses of core samples from the Upper Jurassic Ula Formation in the Norwegian Central Graben were undertaken to quantify the influence of storm waves on sedimentation. Two main facies associations (offshore and shoreface) that form a progradational coarsening upward succession are recognizable within the cores. The offshore deposits are characterized by massive to finely laminated mudstones and fine‐grained sandstones, within a moderately to highly bioturbated complex. The trace fossil assemblage is dominated by deposit‐feeding structures (for example, Planolites, Phycosiphon and Rosselia) and constitutes an expression of the proximal Zoophycos to distal Cruziana ichnofacies. The absence of grazing behaviours and dominance of deposit‐feeding ichnofossils is a reflection of the increased wave energies present (i.e. storm‐generated currents) within an offshore setting. The shoreface succession is represented by highly bioturbated fine‐grained to medium‐grained sandstones, with intervals of planar and trough cross‐bedding, thin pebble lags and bivalve‐rich shell layers. The ichnofossil assemblage, forming part of the Skolithos ichnofacies, is dominated by higher energy Ophiomorpha nodosa ichnofossils and lower energy Ophiomorpha irregulaire and Siphonichnus ichnofossils. The presence of sporadic wave‐generated sedimentary structures and variability in ichnofossil diversity and abundance attests to the influence of storm‐generated currents during deposition. As a whole, the Ula Formation strongly reflects the influence of storm deposits on sediment deposition; consequently, storm‐influenced shoreface most accurately describes these depositional environments.  相似文献   

The angular momenta of solar system bodies: Implications for asteroid strengths     

Joseph A. Burns 《Icarus》1975,25(4):545-554

The angular momentum H is plotted versus mass M for the planets and for all asteroids with known rotation rates and shapes, primarily taken from D. C. McAdoo and J. A. Burns [Icarus18, 285–293 (1973)]. An asteroid's angular momentum is derived from its rotation rate as determined by the period of its lightcurve, its shape as indicated by the lightcurve amplitude, and where possible its size as given by polarimetry or radiometry. The asteroid is assumed to be rotating about its axis of maximum moment of inertia. As previously found by F. F. Fish [Icarus7, 251–256 (1967]) and W. K. Hartmann and S. M. Larson [Icarus7, 257–260 (1967)], H is approximately proportional to $\text{M}{}^{\mathrm{<mtext>5</mtext><mtext>3</mtext>}}$, which shows that the asteroids and most planets spin with nearly the same rate. The very smallest asteroids on the plot deviate from the above reaction, usually containing excess angular momentum. This suggests that collisions have transferred substantial angular momentum to the smallest asteroids, perhaps causing their internal stress states to be substantially modified by centrifugal effects.The forces produced by gravitation are then compared to centrifugal effects for a rotating, triaxial ellipsoid of density 3 g cm^?3. For all asteroids with known properties the gravitational attraction is shown to be larger than the centrifugal acceleration of a particle on the surface: thus the observed asteroid regoliths are gravitationally bound. Poisson's equation for the gravitational potential is investigated and it is shown by mathematical and physical arguments that any arbitrarily shaped ellipsoid with the attractive surface force boundary condition found above will have only attractive internal forces. Thus the internal stress states in asteroids are always compressive so that asteroids could be internally fractured without losing their integrity.  相似文献   

Ionospheric Day-to-Day Variability Around the Whole Heliosphere Interval in 2008     

Wenbin Wang  Jiuhou Lei  Alan G. Burns  Liying Qian  Stanley C. Solomon  Michael Wiltberger  Jiyao Xu 《Solar physics》2011,274(1-2):457-472

Ionospheric F2 peak electron densities (NmF2) measured at ten ionosonde stations have been analyzed to investigate ionospheric day-to-day variability around the Whole Heliosphere Interval (WHI) in 2008 (Day of Year (DOY) 50?–?140). The ionosonde data showed that there was significant global day-to-day variability in NmF2. This variability had 5-, 7-, 9-, 11-, 13.5-, and 16?–?21-day periodicities. At middle latitudes, the ionosphere appeared to respond directly to the solar-wind and interplanetary-magnetic-field (IMF) induced geomagnetic-activity forcing, with the day-to-day variability having the same periods as those in the solar-wind/IMF and geomagnetic activity. At the geomagnetic Equator, the ionosphere had a strong 7-day periodicity, corresponding to the same periodicity in the IMF B _z component. In the equatorial anomaly region, the ionosphere showed more complicated day-to-day variability, dominated by the 9-day periodicity. In addition, there were also periodicities of 11 days and 16?–?21 days in the ionosonde data at some stations. The ionosonde data were compared with the Coupled Magnetosphere Ionosphere Thermosphere (CMIT) simulations that were driven by the observed solar-wind and IMF data during the WHI. The CMIT simulations showed similar ionospheric daily variability seen in the data. They captured the positive and negative responses of the ionosphere at middle latitudes during the first corotating interaction region (CIR) event in the WHI. The response of the model to the second CIR event, however, was relatively weak.  相似文献   

Upscaling facies models to preserve connectivity of designated facies     

Erick R. Burns  Larry R. Bentley  Rene Therrien  Clayton V. Deutsch 《Hydrogeology Journal》2010,18(6):1357-1373

An upscaling algorithm has been developed that generates an irregular coarse grid that preserves flow connectivity by applying a rule-based upscaling algorithm to a fine-scale facies distribution. The algorithm is demonstrated using stochastically generated paleo-fluvial facies distributions. First, an irregular grid honoring the channel facies is created, followed by computation of effective anisotropic parameters for all coarse-grid cells. For the apparent layer-cake geometry of overbank deposits seen in outcrop, two local upscaling methods are compared: (1) the layered system approximation and (2) the mode. To assess upscaling performance, flow simulations for the original and upscaled grids are compared. The horizontal layered approximation (arithmetic mean) performs poorly, over-predicting lateral connectivity where even infrequent disconnection becomes important. Performance of the mode as an upscaling algorithm depends on the probability that a coarse-grid cell will be dominated by a single facies, and it performs surprisingly well because the upscaled grid-generation algorithm honors the channels, informing the upscaling process. Lastly, the irregular coarse grid was compared to a uniform coarse grid, showing superior performance with the irregular grid. The reduction in grid size achieved by irregular-grid generation will be a function of the geometrical complexity of the geologic objects to be honored.  相似文献