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1.
H. G. Dawe 《The Photogrammetric Record》1969,6(34):335-347
This paper describes the planning and implementation of a very extensive aerial survey contract undertaken by Hunting Surveys on behalf of the Hong Kong Government. From photography carried out during January and February 1963, photogrammetric plotting at 1 : 600 and 1 : 1200 proceeded steadily over a period of 5 years to the point where all but the highest land in the Colony had been surveyed at one or other of these two large scales. The problems arising from the rather unique terrain conditions and the urban and industrial development of Hong Kong are dealt with mainly from the photographic and photogrammetric aspect but reference is made to the contribution of the Crown Lands and Survey Office of the Public Works Department of Hong Kong, who provided all ground control and undertook field verification. 相似文献
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钙稀土氟碳酸盐矿物中新多型体的HREM研究 总被引：1，自引：0，他引：1
利用高分辨电子显微术（ＨＲＥＭ）研究了钙稀土氟碳酸盐矿物系列中氟碳铈矿（Ｂ）／直氟碳钙铈矿（Ｓ）的混层结构。发现并确定了Ｂ＿５Ｓ＿２（ＩＨ，３Ｒ）、Ｂ＿５Ｓ＿４（３Ｒ，６Ｒ）和Ｂ＿（１８）Ｓ＿（１０）（ＩＨ）规则混层矿物中５种新多型的晶体结构类型、晶胞参数以及理论晶体化学式等。ＨＲＥＭ研究揭示出，在Ｂ＿ｍＳ＿ｎ（ｍ＞ｎ）型规则混层矿物新多型体的结晶过程中，成矿地质环境是复杂的。阐明了这些多型体是由该系列矿物中的氟碳铈矿（Ｂ）和直氟碳钙铈矿（Ｓ）结构单元层以不同比例沿ｃ轴方向的有序堆垛构成。 相似文献
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Natural gas can have two distinct origins, biogenic and thermogenic sources. This paper investigates the types and maturities of natural gas present in the SE Columbus basin, offshore Trinidad. The chemical composition and the isotope ratios of C and H were determined for approximately 100 samples of natural gas from eight areas within the SE Columbus basin. These compositions and isotopic data are interpreted to identify the origins of gas (biogenic, thermogenic) and maturity. The data showed that the gases in the SE Columbus basin are of both biogenic and thermogenic origin with a trend of mainly thermogenic to mixed to biogenic when moving from SW to NE across the basin. This trend suggests differential burial of the source rock. The presence of mixed gas indicates there was migration of gas in the basin resulting in deeper thermogenic gas mixing with shallow biogenic gas. 相似文献
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D. Heath Jones Will Saunders Matthew Colless Mike A. Read Quentin A. Parker Fred G. Watson Lachlan A. Campbell Daniel Burkey Thomas Mauch Lesa Moore Malcolm Hartley Paul Cass Dionne James Ken Russell Kristin Fiegert John Dawe John Huchra Tom Jarrett Ofer Lahav John Lucey Gary A. Mamon Dominique Proust Elaine M. Sadler Ken-ichi Wakamatsu 《Monthly notices of the Royal Astronomical Society》2004,355(3):747-763
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Khan R. Gamberg B. Power D. Walsh J. Dawe B. Pearson W. Millan D. 《Oceanic Engineering, IEEE Journal of》1994,19(4):540-548
Northern Radar's Cape Race Ground Wave Radar (GWR) system became operational in the fall of 1990. The radar facility has the potential to provide surveillance of over 160000 square kilometres of the Grand Banks off Newfoundland, from a coastal station. GWR is a multipurpose sensor capable of detecting ships, monitoring icebergs and sea-ice, and measuring surface currents and sea state. The radar system employs a frequency modulated interrupted continuous wave (FMICW) as the transmit waveform. This waveform uses a pulse compression technique that combines good range resolution and high maximum range with a relatively high duty cycle. In this paper, we describe the implementation of the FMICW waveform in a practical real time radar system. We also show some examples of vessel, iceberg, acid aircraft detection and tracking using the Cape Race facility. These examples demonstrate that the Cape Race GWR may be used as an effective tool to assist in the management, surveillance, and enforcement of Canadian interests in the Exclusive Economic Zone 相似文献
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Darrell R.J. Mullowney Corey J. MorrisEarl G. Dawe Katherine R. Skanes 《Marine Policy》2012,36(3):567-575
The Hawke Box trawling exclusion zone off southern Labrador is a 8610 km2 closed area implemented in 2003 to protect soft-shelled pre-recruit Snow Crab and juvenile cod from mortality imposed by shrimp trawling and other bottom-impact fisheries. This study utilizes survey, logbook, and observer data from the Snow Crab and Northern Shrimp fisheries to assess the effectiveness of the Hawke Box in protecting and possibly enhancing the Snow Crab resource off southern Labrador. The results indicate that the exclusion zone has failed to protect pre-recruit crabs largely due to a redistribution and intensification of directed Snow Crab effort inside the Box in the years following closure. This unexpected outcome resulted in a high level of fishery-induced mortality to pre-recruit crabs and masked any potential positive outcomes from the cessation of trawling. The shortcomings that contributed to the failure of this exclusion area are discussed in relation to the current state of knowledge on the effectiveness of marine protected areas in general as management tools for conserving aquatic resources. 相似文献
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The Canadian Species at Risk Act (SARA) was implemented in 2003. Since 2003, no fully marine Atlantic Canadian fish species has been listed and some observers are seriously questioning the extent to which SARA is effectively protecting marine fish species. Three species of wolffish found in North Atlantic waters were placed onto the SARA list in 2003 when it was implemented. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) originally listed these species in 2000 and 2001. The COSEWIC listings were based on catch-rate trends over large spatial scales from a relatively short time series of offshore research vessel survey data and status reports derived from research for an honours thesis. This case study of the wolffish listings draws on results from semi-structured interviews with key informants familiar with the listing and post-listing events, an analysis of existing documents and research on the SARA process, and on data from wolffish-focused Local Ecological Knowledge (LEK) interviews with commercial fish harvesters in the Northern Gulf of St. Lawrence. The results shed light on the wolffish listing process including perceptions of how the implementation of SARA has affected the process and prospects for listing fully marine species. The post-SARA listing developments in relation to wolffish, including harvesters' views about the listing are also explored. The results indicate mixed views about the benefits and problems associated with the requirement for public consultations and incorporation of stakeholder knowledge into the listing process under SARA. There is some evidence that the wolffish listing process has increased harvester stewardship and engagement and benefitted from their input into the safe release of wolffish. Finally, little attention has been paid by any of the stakeholder groups consulted to the potential future delisting of wolffish, arguably the most important goal of species conservation initiatives. Without delisting requirements or timelines set out in a species recovery plan it is impossible to establish concrete guidelines for recovery. 相似文献
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A software detection model has been developed to predict the returned Doppler spectrum for an iceberg target for ground-wave Doppler radars. This software model is based on proposed new estimates for the backscattered Doppler-dependent iceberg cross section for assumed iceberg models, as well as the backscattered Doppler spectrum from the ocean surface. The model includes estimates for forward and reverse transmission losses, based on classical spherical earth derivations. In addition, the transmission losses account for the effects of surface roughness through a modified surface impedance. Standard estimates for man-made and atmospheric noise have been considered in the detection model. A comparison between the results predicted by the detection model and data acquired during an experiment conducted at Byron Bay, Labrador, Canada has been effected. The hardware used for the experiment was an HF Doppler radar operating at 25.40 MHz. The transmitting antenna was a three-element Yagi array and the receiving antenna a 24-element narrow-beam linear array. By using iceberg ground truthing information the Doppler spectrum for individual icebergs was predicted using the software model. The predicted spectra were compared with the received spectra on a target signal-to-noise power ratio basis. The results of this comparison give a degree of confidence to the detection model and show that ground-wave radars are effective ice hazard remote sensors. 相似文献
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The response of the thermocline to changes in atmospheric forcing are explored in two 50-year hindcast North Pacific model runs. The model runs only differ in their resolution and horizontal viscosity values. The thermocline response is explored through a modal decomposition. The first baroclinic mode response is qualitatively similar in both model runs, with a somewhat smaller response in the lower resolution model. This mode is primarily wind driven. The second baroclinic mode shows a larger response at midlatitudes in the low-resolution model than in the higher resolution model. This is consistent with the presence of very large-scale baroclinic instability in the return flow of the subtropical gyre at low-resolution, and represents a spurious response of the ocean model to large horizontal viscosity. This spurious mode of decadal variability in the thermocline is maintained even when there is variability in atmospheric forcing. This result suggests that care must be taken in interpretation of the realism of mid-latitude modes of variability centered in western boundary current extensions of coupled ocean–atmosphere models. 相似文献