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Peter J. Rimmer 《GeoJournal》1999,48(1):43-65
There is a need to move from discussing the Asia-Pacific Rim's leading port cities as shipping centres measured by container
throughput. This shift in focus involves examining how different transport and telecommunications systems are interacting
with each other at an international scale under the power and control of major world operators. Using a three-level network
framework an attempt is made to illustrate and explain the formation of multilayered trade/communications corridors and hubs/headquarters
in the Asia-Pacific Rim since the mid-1980s and to identify the factors affecting them. From this examination of spatial structure
and corporate control three levels of cities in the Asia-Pacific Rim are recognised: first level cities with strong corporate
representation in container shipping, air cargo, air passenger and telecommunications; second level cities with marked corporate
representation in one but not all four modes; and third level cities with no marked corporate representation in any mode but
with strong throughput. The third level includes the Asia-Pacific Rim's ‘true’ port cities. Perhaps the ambiguous category
‘port city’ should be reserved for them.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Darren R. Gröcke Susan M. Rimmer Lois E. Yoksoulian Bruce Cairncross Harilaos Tsikos Jeroen van Hunen 《Earth and Planetary Science Letters》2009,277(1-2):204-212
The Early Jurassic Toarcian oceanic anoxic event (T-OAE) and concurrent negative carbon-isotope (δ13C) excursion have recently been attributed to either the release of methane (CH4) clathrates or thermogenic CH4 gas associated with the Karoo-Ferrar large igneous province (LIP) into coals and organic-rich shales. 12C-enriched thermogenic CH4 production associated with the Karoo-Ferrar would result in residual material being 12C-depleted nearer the intrusions. In this study, geochemical analyses (carbon isotopes, volatile matter (VM), vitrinite reflectance (Ro)) are reported for two coal transects associated with dykes intruding the No. 4L coal in the Highveld Coalfield, Karoo Basin, South Africa. VM decreases from over 35% to around 15% in one transect, and the second transect shows a less pronounced decrease (from > 25% to ~ 16%). Accompanying the decrease in VM content is an increase in Ro from background levels of around 0.7% to over 4% adjacent to the dyke; used as a palaeo-geothermometer, Ro values indicate background temperatures of ~ 100 °C increasing to > 300 °C close to the contact. Despite changes in VM and Ro, there are no significant changes in δ13C, certainly not of the magnitude that would be expected associated with large-scale thermogenic CH4 generation. These and other Gondwanan coals have low vitrinite and liptinite contents (components more prone to CH4 generation), in part explaining the modest decreases in VM adjacent to the dykes. This, combined with the relatively narrow metamorphic aureole surrounding the intrusions and the likelihood that at least some of the volatiles generated by the intrusion were trapped as coalbed CH4 or condensed as pyrolytic carbon, suggests only limited CH4 release. In addition, based on original estimates of moisture contents in these coals and the depth at time of intrusion (1,000–2,000 m) the dykes would have lost most of their energy heating and evaporating water, thus having very little remaining energy to generate thermogenic CH4. 相似文献
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THE PROBLEM OF COMPARING AND CLASSIFYING SEAPORTS 总被引:1,自引:0,他引:1
Peter J. Rimmer 《The Professional geographer》1966,18(2):83-91
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Ami Nishri Alon Rimmer Udi Wagner Zvi Rosentraub Peter Yeates 《Aquatic Geochemistry》2011,17(3):195-207
High resolution chemical data collected during summer 2003 indicate that the lower water mass (LWM) of the thermally stratified
Lake Kinneret (LK) can be subdivided into three layers: a benthic boundary layer (BBL), overlain by the hypolimnion (HYP),
and on top, the lower part of the metalimnion (ME-L). After onset of thermal stratification, the BBL is the first layer that
turns anoxic, followed shortly afterward by the ME-L, while the HYP remains oxic and has relatively higher pH until later
in summer. Thus, during the early summer, the HYP forms an oxygen-containing layer in-between two DO-deficient layers. Somewhat
later, the HYP is characterized by still having significant levels of nitrate NO3, while in both adjacent layers nitrate is already removed through denitrification. The mechanisms controlling the gradual
decline of dissolved oxygen (DO) in the HYP during the summer were studied. The seasonal mean lake-wide vertical eddy diffusion
coefficient in this layer, evaluated from heat flux measurements, is approximately 4 × 10−6 m2 s−1. The vertical oxygen flux due to diffusion from within the HYP toward its oxygen-deficient upper and lower boundaries accounts
for most of the slow summer decline in DO in this layer. A smaller portion of this decline can be attributed to in-layer respiratory
processes. The low turbidity, relatively high pH, and slow accumulation rate of NH4 in the HYP support the notion that the slower mineralization processes occurring in this layer result from relatively low
ambient concentrations of biodegradable organic matter, most probably due to the short residence time of the particles settling
through this layer. 相似文献
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Ice crystal clouds have an influence on the radiative budget of the earth; however, the exact size and nature of this influence has yet to be determined. A laboratory cloud chamber experiment has been set up to provide data on the optical scattering behaviour of ice crystals at a visible wavelength in order to gain information which can be used in climate models concerning the radiative characteristics of cirrus clouds. A PMS grey-scale probe is used to monitor simultaneously the cloud microphysical properties in order to correlate these closely with the observed radiative properties. Preliminary results show that ice crystals scatter considerably more at 90° than do water droplets, and that the halo effects are visible in a laboratorygenerated cloud when the ice crystal concentration is sufficiently small to prevent masking from multiple scattering. 相似文献