5 resultados para Image of mathematics
em Publishing Network for Geoscientific
Resumo:
The study of the Neogene (Miocene to Holocene) stratigraphic record on the glaciated Atlantic margin of NW Europe has, to date, largely been undertaken on an ad-hoc basis. Whereas a systematic approach to understanding the stratigraphic development of Palaeogene and older strata has been undertaken in areas such as the North Sea, West of Shetland and Norway, the problem of establishing a Neogene framework has been only partly addressed by academia and the oil industry. In most cases where a Neogene stratigraphy has been constructed, this has been largely in response to problem solving and risk assessment in a restricted area. Nevertheless, in the past few years it has become increasingly apparent that there is a common history in the Neogene development of the passive Atlantic margin of NW Europe, between mid-Norway and SW Ireland. The inspection and interpretation of an extensive geophysical and geological database has identified several regionally significant and correlatable unconformities along this continental margin. Thus, a regional approach to the stratigraphical development of the Neogene succession on the glaciated European Atlantic margin is undertaken in this volume.
Resumo:
Aerial observations of light pollution can fill an important gap between ground based surveys and nighttime satellite data. Terrestrially bound surveys are labor intensive and are generally limited to a small spatial extent, and while existing satellite data cover the whole world, they are limited to coarse resolution. This paper describes the production of a high resolution (1 m) mosaic image of the city of Berlin, Germany at night. The dataset is spatially analyzed to identify themajor sources of light pollution in the city based on urban land use data. An area-independent 'brightness factor' is introduced that allows direct comparison of the light emission from differently sized land use classes, and the percentage area with values above average brightness is calculated for each class. Using this methodology, lighting associated with streets has been found to be the dominant source of zenith directed light pollution (31.6%), although other land use classes have much higher average brightness. These results are compared with other urban light pollution quantification studies. The minimum resolution required for an analysis of this type is found to be near 10 m. Future applications of high resolution datasets such as this one could include: studies of the efficacy of light pollution mitigation measures, improved light pollution simulations, economic and energy use, the relationship between artificial light and ecological parameters (e.g. circadian rhythm, fitness, mate selection, species distributions, migration barriers and seasonal behavior), or the management of nightscapes. To encourage further scientific inquiry, the mosaic data is freely available at Pangaea.
Resumo:
We describe the contemporary hydrography of the pan-Arctic land area draining into the Arctic Ocean, northern Bering Sea, and Hudson Bay on the basis of observational records of river discharge and computed runoff. The Regional Arctic Hydrographic Network data set, R-ArcticNET, is presented, which is based on 3754 recording stations drawn from Russian, Canadian, European, and U.S. archives. R-ArcticNET represents the single largest data compendium of observed discharge in the Arctic. Approximately 73% of the nonglaciated area of the pan-Arctic is monitored by at least one river discharge gage giving a mean gage density of 168 gages per 106 km2. Average annual runoff is 212 mm yr?1 with approximately 60% of the river discharge occurring from April to July. Gridded runoff surfaces are generated for the gaged portion of the pan-Arctic region to investigate global change signals. Siberia and Alaska showed increases in winter runoff during the 1980s relative to the 1960s and 1970s during annual and seasonal periods. These changes are consistent with observations of change in the climatology of the region. Western Canada experienced decreased spring and summer runoff.