The Digital National Framework and Digital Photogrammetry at Ordnance Survey   总被引：1，自引：0，他引：1  

David A. Holland  & Lynne E. Allan 《The Photogrammetric Record》2001,17(98):291-301

Over recent months the Ordnance Survey, Britain's national mapping agency, has changed the way in which it uses photogrammetry to update its large scales topographic database. The nature of the database itself has also changed during the same period, as the concept of a "Digital National Framework" has developed. This paper describes the Digital National Framework, the topographic data captured by Ordnance Survey within this framework and the capture methods currently used. The paper concentrates on the use of photogrammetry in the update process, describing the methods of the past, the methods currently in production, and the outlook for photogrammetry within the Ordnance Survey in future.  相似文献   

Hydrography of the eastern tropical Pacific: A review   总被引：3，自引：10，他引：3  

Paul C. Fiedler  Lynne D. Talley 《Progress in Oceanography》2006,69(2-4):143

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Mitochondrial DNA analyses of narrow-barred Spanish mackerel (Scomberomorus commerson) suggest a single genetic stock in the ROPME sea area (Arabian Gulf, Gulf of Oman, and Arabian Sea)     

Hoolihan  John P.; Anandh  Prem; van Herwerden  Lynne 《ICES Journal of Marine Science》2006,63(6):1066-1074

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Remote Sensing of Mangrove Change Along the Tanzania Coast     

Yeqiao Wang  Gregory Bonynge  Jarunee Nugranad  Michael Traber  Amani Ngusaru  James Tobey  Lynne Hale  Robert Bowen  Vedast Makota 《Marine Geodesy》2003,26(1):35-48

This article contributes to the understanding of the changes in distribution and total area of mangrove forests along the mainland Tanzania coast over the past decade. Mangroves are recognized as critical coastal habitat requiring protection and special attention. The Tanzania coastline forms a suitable habitat for establishment of mangrove forests. Mangrove forests are distributed from Tanga in the north to Mtwara in the south covering approximately 109,593 hectares from 1988-1990 and about 108,138 hectares in 2000. The largest continuous mangrove stands are found in the districts of Rufiji, Kilwa, Tanga-Muheza, and Mtwara. Comparison of data between these two time periods shows that the geographic coverage of mangroves has no dramatic change in the past decade. The Tanzania Mangrove Management Project and other closely related programs and efforts pertaining to mangrove conservation contribute to direct restoration and natural regeneration of mangroves. This study documents the changes of mangroves and demonstrates that remote sensing and GIS offer important data and tools in the advancement of coastal resource management and ecosystem monitoring. Application of geographic information technologies is critical for improved coastal resources management and decision making for sustainable development in Tanzania.  相似文献   

Hydrological modelling using data from monthly GCMs in a regional catchment          下载免费PDF全文

Renji Remesan  Tim Bellerby  Lynne Frostick 《水文研究》2014,28(8):3241-3263

This study demonstrates the use of spatially downscaled, monthly general circulation model (GCM) rainfall and temperature data to drive the established HyMOD hydrological model to evaluate the prospective effects of climate change on the fluvial run‐off of the River Derwent basin in the UK. The evaluation results of this monthly hydrological model using readily available, monthly GCM data are consistent with studies on nearby catchments employing high‐temporal resolution data, indicating that useful hydro‐climatic planning studies may be possible using standard datasets and modest computational resources. HyMOD was calibrated against 5 km² gridded UK Climate Projections dataset data and then driven using monthly spatially interpolated (~5 km²) outputs from Hadley Centre Coupled Model, version 3 and the Canadian Centre for Climate Modelling and Analysis for Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC‐SRES) A2a and B2a covering the 2020s, 2050s and 2080s. Results for both GCMs project a decrease in annual run‐off in both GCM models and scenarios with higher values in the summer/autumn months, whereas an increase in the later winter months. Both Hadley Centre Coupled Model, version 3 and the Canadian Centre for Climate Modelling and Analysis show higher ranges of uncertainty during the winter season with higher values of run‐off associated with December in all three simulation periods and two scenarios. A seasonal comparison of run‐off simulations shows that both GCMs give similar results in summer and autumn, whereas disparities due to GCM uncertainties are more conspicuous in winter and spring. In this study, both the GCMs under A2a scenario have demonstrated the high possibility of time shift in monthly average peak run‐offs in the Derwent River by 2080s in comparison with the early 21st century. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Environmental variables and their association with faecal coliform and faecal streptococci densities at thirteen Sydney beaches     

Martin Krogh  Lynne Robinson 《Marine pollution bulletin》1996,33(7-12):239-248

Environmental variables and their association with faecal coliform and streptococci densities were investigated at a number of Sydney's metropolitan beaches. High variability in faecal coliform and faecal streptococci densities was observed at most beaches. The ability of the various models to explain the observed variation in faecal coliform or streptococci levels was relatively low, although they did provide an insight into the more influential environmental factors involved. Rainfall has the single most important effect on faecal coliform and streptococci densities at Sydney beaches. Whether this is due to increased stormwater runoff at the beaches, increased discharge through the outfalls (both the deepwater ocean outfalls and the few remaining shoreline outfalls), or a combination of both is unclear and is likely to depend on the individual beach being considered. Elevated levels of faecal coliforms and streptococci are still occasionally observed at some beaches, but these levels are usually not as high nor as frequent as they were prior to commissioning of the deepwater outfalls. The significant associations of current and plume entrapment with faecal coliform and streptococci densities at some Sydney beaches suggest that under certain conditions, effluent from the deepwater ocean outfalls can still influence faecal coliform and streptococci densities at these beaches.  相似文献   

Global Warming and Water Management: Water Allocation and Project Evaluation     

Robert Mendelsohn  Lynne L. Bennett 《Climatic change》1997,37(1):271-290

This paper explores the sensitivity of the benefits of alternative water allocation schemes and of project evaluation to global warming. If global warming shifts the mean of annual water supplies, there could be large impacts on the expected values of alternative water allocation schemes. The first section of the paper explores how well alternative schemes (such as market mechanisms, prior rights, or percentage flows) perform if the distribution of flows changes. In a case study of the Colorado River, market mechanisms and flow guarantees result in smaller impacts than rules which allocate inefficient percentages of flows to heterogeneous users. The second part of the paper explores the effect of a gradually changing distribution of flows on project evaluations. Project evaluation is sensitive to predicted future changes in mean flows. Project evaluation is not sensitive to changes in the variance of future flows unless the variance increase is large and the benefit measure is highly curvilinear. Because basin-specific changes in runoff from global warming are currently uncertain and much delayed, most project analyses will be unaffected by global warming. The most important response by water managers to climate change may simply be to closely monitor runoff and incorporate flexible rules in order to adapt their behavior to observed changes.  相似文献   

Multimolecular data processing and display in organic geochemistry: The evaluation of petroporphyrin GC-MS data     

Christian B. Eckardt  Lynne Dyas  Peter W. Yendle  Geoffrey Eglinton 《Organic Geochemistry》1988,13(4-6)

A novel method for handling and presenting multimolecular abundance data, derived from gas chromatographic-mass spectrometric analyses (GC-MS), is introduced. The method facilitates carbon number labeling of compounds, specifically in the case of porphyrins, by means of a porphyrin-index, which is part of a novel identification code for porphyrins. Identification code, relative abundance and structure information of each compound recognised are stored in a database, which affords a variety of characteristic displays and tables upon manipulation. The combined facilities allow the direct comparison of samples of different origin, maturity and/or palaeoenvironment. Correlation studies, such as oil/oil or oil/source rock, are also facilitated by comparison of characteristic “fingerprint” histogram patterns. The ability of the method is exemplified through analysis of the porphyrin distributions of Boscan oil, La Luna shale, Gilsonite bitumen and Serpiano shale.  相似文献   

The wavelength dependence of granulation (0.38–2.4 μm)     

F. Albregtsen  T. Lynne Hansen 《Solar physics》1977,54(1):31-33

Using 2 pinhole photometers the intensity of the undisturbed photosphere was recorded simultaneously in 6 and in 4 wavelength regions. The rms value of the intensity variation in each of the 10 wavelength regions decreases slightly with increasing value of the heliocentric angle; this result confirms recent observations by other authors and supports the critique of the results given by Edmonds (1964).We report the detection of a secondary maximum in the wavelength dependence of the intensity variation at 1.5 m.  相似文献   

Linking large-parallax Spitzer–CFHT–VLT astrometry of asteroids     

Mikael Granvik  Karri Muinonen  Lynne Jones  Bidushi Bhattacharya  Marco Delbo  Laura Saba  Alberto Cellino  Edward Tedesco  Don Davis  Victoria Meadows 《Icarus》2007,192(2):475-490

We show that the new ephemeris-space multiple-address-comparison (eMAC) method solves asteroid linking problems despite large parallaxes by applying the method to astrometric asteroid observation sets obtained nearly simultaneously with the Spitzer space telescope, the Canada–France–Hawaii Telescope (CFHT), and European Southern Observatory's Very Large Telescope (VLT). For main-belt asteroids, the parallax between Spitzer and the Earth-based telescopes is approximately one degree which is large as compared to a typical parallax for solely Earth-based telescopes in the arcseconds regime. In the eMAC method, we reduce the initially huge amount of possible linkages between observation sets by comparing samples of ephemerides that have been computed separately for all sets at, say, three common dates. If the non-zero ephemeris probability densities overlap at all common dates, we try to find an orbit solution for these so-called trial linkages. If there exists an orbit which reproduces all the astrometric observations assuming predefined observational errors, we call it a linkage. Known asteroids are independently identified among Spitzer, CFHT, and VLT astrometry, and comparing the identified observations to the linkages found shows that the method found all known correct linkages present in the data. In addition, we also found five previously unpublished linkages between Spitzer astrometry and Earth-based astrometry. Based on our simulations, we found virtually all Spitzer-related linkages between two single-night observation sets, and more than 99.4% of linkages between two single-night observation sets obtained by Earth-based observatories. Virtually all correct linkages consisting of at least three single-night sets were also detected. The results show that large-parallax discovery observations made from a spacecraft can be linked to Earth-based follow-up observations to ensure that the objects are not lost. Furthermore, we compute the heliocentric and Spitzer-centric distances as well as the corresponding solar phase angles at the dates of Spitzer observations. Based on comparisons to simulated geocentric observations, we also show that, for typical nearly-simultaneous observations, the parallax reduces the distance uncertainties by several orders of magnitude.  相似文献