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利用重建数据和模拟数据探讨中国东部1380—1429年雨涝期与气候系统内部变率之间的联系。结果显示:1380—1429年全球大多数区域发生了严重的旱涝事件,揭示了中国东部雨涝气候可能是对大尺度大气环流调整下的响应,可能与该时期赤道太平洋类La Niña海温分布、太平洋年代际振荡(PDO)冷位相、北大西洋年代际振荡(AMO)暖位相、北大西洋涛动(NAO)正位相相关。全球海气耦合模式尽管能够模拟出该时期非洲和欧洲区域的干湿空间分布状况,但模拟的中国东部、北美和南美的干湿状况与重建相反。其可能的原因或许是模式虽正确模拟出了NAO正位相及弱的印度洋偶极子(IOD)负位相,但无法正确刻画赤道太平洋类La Niña海温分布、北太平洋PDO冷位相及北大西洋AMO暖位相。 相似文献
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The current risk management approach for the Norwegian offshore petroleum industry came into effect in 2001 and has been stable with minor changes for 15 years. Relatively few new installations were slated for development until quite recently, and several new projects have been started in the last few years. The paper considers the risk management approach in the pre-FEED phase and builds on two case studies selected from the most recent cases. These case studies have been evaluated with respect to how uncertainties are considered in the early phase, based on the submission of the Plan for Development and Operation, their evaluations by authorities and the supporting documents. Both case studies involve new concepts for which there is no experience from similar environments and/or water depths. In spite of what could have been expected, the case studies conclude that uncertainties have not been in focus at all during concept development. This appears to be definitely the case for the licensees, but also to be the case for the authorities. Some suggestions are presented for what could have been considered by the licensees and authorities. 相似文献
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Peter M. Kiffney Jennifer P. Bull Michael C. Feller 《Journal of the American Water Resources Association》2002,38(5):1437-1451
ABSTRACT: Climate data from the Malcolm Knapp Research Forest (MKRF) in the Coast Range mountains of southwestern British Columbia were used to examine relationships between climate and hydrology and variations in the El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Air and water temperatures were higher and precipitation was lower during in‐phase or warm PDO/E1 Niño events than in other years. In contrast, in‐phase or cool PDO/La Niña years were generally cooler and wetter than other years. Precipitation and East Creek discharge were positively related to the Southern Oscillation Index (SOI) and negatively related to the PDO index. Conversely, air and water temperatures were negatively related to the SOI and positively related to the PDO index. Differences in precipitation and air temperature were also evident at longer time scales when separated by PDO phase. Because of drier conditions during in‐phase El Niño events, the flow of organic matter from East Creek to downstream portions of the channel network was lower compared to other years. This reduction has implications for downstream communities, as these subsidies provide a major source of energy for stream food webs. Therefore, short term and long term shifts in climate, discharge, and water temperature may have profound impacts on the ecology of Pacific Northwest (PNW) watersheds due to changes in a number of ecosystem processes such as altered flux of organic matter from headwater streams to larger rivers. 相似文献
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Yusaku?SakataEmail author Thallada?Bhaskar Md. Azhar?Uddin Akinori?Muto Toshiki?Matsui 《Journal of Material Cycles and Waste Management》2003,5(2):113-124
Dehalogenation is a key technology in the feedstock recycling of mixed halogenated waste plastics. In this study, two different methods were used to clarify the effectiveness of our proposed catalytic dehalogenation process using various carbon composites of iron oxides and calcium carbonate as the catalyst/sorbent. The first approach (a two-step process) was to develop a process for the thermal degradation of mixed halogenated waste plastics, and also develop dehalogenation catalysts for the catalytic dehydrochlorination of organic chlorine compounds from mixed plastic-derived oil containing polyvinyl chloride (PVC) using a fixed-bed flow-type reactor. The second approach (a single-step process) was the simultaneous degradation and dehalogenation of chlorinated (PVC) and brominated (plastic containing brominated flame retardant, HIPS–Br) mixed plastics into halogen-free liquid products. We report on a catalytic dehalogenation process for the chlorinated and brominated organic compounds formed by the pyrolysis of PVC and brominated flame retardant (HIPS–Br) mixed waste plastics [(polyethylene (PE), polypropylene (PP), and polystyrene (PS)], and also other plastics. During dehydrohalogenation, the iron- and calcium-based catalysts were transformed into their corresponding halides, which are also very active in the dehydrohalogenation of organic halogenated compounds. The halogen-free plastic-derived oil (PDO) can be used as a fuel oil or feedstock in refineries. 相似文献
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