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11.
John Ryks Jonathan Kilgour Jesse Whitehead Amy Whetu James Whetu 《New Zealand geographer》2019,75(3):152-162
During the 1990s, the township of Pōkeno was held up as an example of a declining rural Aotearoa/New Zealand. By‐passed from the national state highway, it lost its status as a service hub and drastic measures were introduced to revitalise the town, including renaming the town “ Jenniferann.com .” Pōkeno has since undergone an unlikely transformation, with foreign investment and its location within an extended Auckland commuter zone meaning that the township has grown exponentially. This article describes the transformation of Pōkeno and uncovers what has been missing from discussions about Pōkeno's reinvention, namely, the place of mana whenua. 相似文献
12.
Characterization of chromophoric dissolved organic matter (CDOM) in the Baltic Sea by excitation emission matrix fluorescence spectroscopy 总被引:11,自引:0,他引:11
Piotr Kowalczuk Joanna Sto-Egiert William J. Cooper Robert F. Whitehead Michael J. Durako 《Marine Chemistry》2005,96(3-4):273-292
Chromophoric dissolved organic matter (CDOM) is the major light absorber in the Baltic Sea. In this study, excitation emission matrix (EEM) fluorescence spectra and UV–visible absorption spectra of CDOM are reported as a function of salinity. Samples from different locations and over different seasons were collected during four cruises in 2002 and 2003 in the Baltic Sea in both Pomeranian Bay and the Gulf of Gdansk. Absorption by CDOM decreased with increased distance from the riverine source and reached a relatively stable absorption background in the open sea. Regression analysis showed that fluorescence intensity was linearly related to absorption by CDOM at 375 nm and aCDOM(375) absorption coefficients were inversely related to salinity. Analysis of CDOM-EEM spectra indicated that a change in composition of CDOM occurred along the salinity gradient in the Baltic Sea. Analysis of percent contribution of respective fluorophore groups to the total intensity of EEM spectra indicated that the fluorescence peaks associated with terrestrial humic components of the CDOM and total integrated fluorescence decreased with decreasing CDOM absorption. In contrast, the protein-like fraction of CDOM decreased to a lesser degree than the others. Analysis of the percent contribution of fluorescence peak intensities to the total fluorescence along the salinity gradient showed that the contribution of protein-like fluorophores increased from 2.6% to 5.1% in the high-salinity region of the transect. Fluorescence and absorption changes observed in the Baltic Sea were similar to those observed in similar transects that have been sampled elsewhere, e.g. in European estuaries, Gulf of Mexico, Mid-Atlantic Bight and the Cape Fear River plume in the South Atlantic Bight, although the changes in the Baltic Sea occurred over a much smaller salinity gradient. 相似文献
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14.
J. A. Whitehead 《地球物理与天体物理流体动力学》2013,107(1):161-180
AbstractExperimental and theoretical results are described for the moving flame experiment, where a heat source moves under a horizontal, annular channel filled with liquid mercury. The physical range under discussion consists of the creep flow limit, in which inertial forces are less than viscous forces. A mean surface flow was observed on the mercury. This flow was up to four times greater than the heater speed, and in an opposite direction. The ratio of mean flow to heater speed was theoretically and experimentally found to be proportional to the square of the thermal amplitude, in agreement with a special limit of Davey's earlier results. The basic flow here, as contrasted to those flows analyzed by earlier theories, appears to be generated by surface tension. However, the Reynolds stress mechanism which generates the mean flow is the same. Some experimental flows were so rapid that the range of validity of the present, as well as some earlier theories, was exceeded. The present theory suggests that the higher order nonlinearities may have cancellative effects, which implies that the present and some earlier theories are valid beyond their normal range of validity. 相似文献
15.
Increasing reliance on natural gas (methane) to meet global energy demands holds implications for atmospheric CO2 concentrations. Analysis of these implications is presented, based on a logistic substitution model viewing energy technologies like biological species invading an econiche and substituting in case of superiority for existing species. This model suggests gas will become the dominant energy source and remain so for 50 years, peaking near 70 percent of world supply. Two scenarios of energy demand are explored, one holding per capita consumption at current levels, the second raising the global average in the year 2100 to the current U.S. level. In the first (efficiency) scenario concentrations peak about 450 ppm, while in the second (long wave) they near 600 ppm. Although projected CO2 concentrations in a methane economy are low in relation to other scenarios, the projections confirm that global climate warming is likely to be a major planetary concern throughout the twenty-first century. A second finding is that data on past growth of world per capita energy consumption group neatly into two pulses consistent with longwave theories in economics. 相似文献
16.
R. Milne J. D. Deans E. D. Ford P. G. Jarvis J. Leverenz D. Whitehead 《Boundary-Layer Meteorology》1985,32(2):155-175
Estimates of hourly transpiration from a 16–17 yr old Sitka spruce forest were calculated from the Penman-Monteith combination equation and compared with estimates from an eddy correlation/energy balance method.Canopy conductances were estimated from stomatal conductances measured using null balance diffusion porometers and took account of canopy variations of stomatal conductance and needle area index.Vertical heat fluxes were measured by the eddy correlation method; transpiration fluxes were then estimated from an energy balance of the forest.There was not a 1:1 relationship between the estimates of transpiration from the two methods. The major sources of error were concluded to be (i) difficulties of estimating the variation in stomatal conductance and leaf area through the canopy, (ii) errors in the value of total leaf area index, and (iii) errors in stomatal conductance measurements.The eddy correlation method was suggested as the more useful for future studies of the variation of forest transpiration in time or space, because the Penman-Monteith equation requires extensive biological measurements. 相似文献
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19.
R. E. Whitehead 《Mineralium Deposita》1973,8(2):148-160
The varying response of Fe and Mn to changes in pH and Eh suggests that their ratio may be a sensitive indicator of changes in environment of deposition of sedimentary rocks. A volcanic-sedimentary model for the deposition of a massive stratiform sulphide deposit in northern New Brunswick is proposed and the physico-chemical nature of the various environments discussed. The disposition of the Mn:Fe ratios in sedimentary rocks surrounding the sulphide deposit is entirely consistent with the proposed model.
Zusammenfassung Die unterschiedliche Reaktion von Fe und Mn auf Veränderungen in pH und Eh weist darauf hin, daß ihr Verhältnis ein empfindlicher Indikator für Milieuänderungen bei der Ablagerung von Sedimentgestein sein könnte. Für den Absatz einer massiven schichtförmigen Sulfidlagerstätte im nördlichen Brunswick wird ein vulkano-sedimentäres Modell vorgeschlagen und die physikalisch-chemische Natur der verschiedenen Milieus besprochen. Die Verteilung der unterschiedlichen Fe:Mn-Verhältnisse in dem die Sulfidlagerstätte umgebenden Sedimentgestein deckt sich völlig mit dem angenommenen Modell.相似文献
20.
WORLD DELTAS AND THEIR EVOLUTION 总被引:1,自引:0,他引:1
H. Jesse Walker 《地理学报》1999,(1):30-41
In August 1998, an international symposium on the world deltas was held in New Orleans, Louisiana, USA. This symposium attracted discussion about more than 25 deltas from around the world with emphasis placed on those that are most densely populated and impacted by humans. Keynote papers printed details about the physical, biological, engineering and socioeconomic aspects of six deltas including the Mississippi, Nile, Ganges-Brahmaputra, Rhine-Meuse, Changjiang and Po. The main purpose of this symposium was to inform scientists, engineers and decision-makers about information that is currently available and to provide them a basis for working in such environments. 相似文献