994 resultados para 152-914B
Resumo:
本论文研究的创新之处是在高分辨率的地层层序上选定3米X3米的工作剖面,逐层采集标本,定量研究山旺中新世古气候的变化过程。主要有以下新的认识和结论: 植物化石的数量和种类在地层层序上的变化很大。第5层、第6层、第7层、第13层、第15层和第16层的标本丰富,可以进行CLAMP分析。 第5层、第6层和第7层的泥岩中保存有丰富的植物化石,运用荧光显微分析技术可以清晰地观察到泥岩中植物的气孔和表皮细胞形态。 山旺地区中新世年均温(MAT)在9.5℃和11.3℃之间。较热月份平均温度(WMMT)在19.9 ℃和22.4 ℃之间。生长季月数(GSL)为5.9--6.9个月。生长季节平均降水量(MGSP)为860--1770 mm。生长季月平均降水量(MMGSP)为152--253mm,生长季三个连续最湿的月份降水量(3-WET)为530--920mm,三个连续最旱的月份的降水量(3-DRY)为286--687mm。相对湿度(Rel. Hum)在73%以上,高达80%。特殊湿度(q-Specific Humidity)在5.9--6.7之间,热熵值(H-Enthalpy)为298.5--304.5。 气候参数在地层层序上存在变化。CLAMP分析的结论与最近亲缘种分析(NLR)的结论相似。CLAMP分析的年均温比现在山旺的年均温12.5℃低,比同层的线性分析结果低3℃。与海底有孔虫氧同位素的研究结论一致。山东山旺中新世古气候的研究可以作为中中新世全球气候变化研究的一个标尺。
Resumo:
Linear regression models are constructed to predict seasonal runoff by fitting streamflow to temperature, precipitation, and snow water content across a range of elevations. The models are quite successful in capturing the differences in discharge between different elevation watersheds and their interannual variations. This exercise thus provides insight into seasonal changes in streamflow at different elevation watersheds that might occur under a changed climate.
Resumo:
Scientific and anecdotal observations during recent decades have suggested that the structure and function of the coral reef ecosystems around St. John, U.S. Virgin Islands have been impacted adversely by a wide range of environmental stressors. Major stressors included the mass die-off of the long-spined sea urchin (Diadema antillarum) in the early 1980s, a series of hurricanes (David and Frederick in 1979, and Hugo in 1989), overfishing, mass mortality of Acropora species and other reef-building corals due to disease and several coral bleaching events. In response to these adverse impacts, the National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment, Biogeography Branch (CCMA-BB) collaborated with federal and territorial partners to characterize, monitor, and assess the status of the marine environment around the island from 2001 to 2012. This 13-year monitoring effort, known as the Caribbean Coral Reef Ecosystem Monitoring Project (CREM), was supported by the NOAA Coral Reef Conservation Program as part of their National Coral Reef Ecosystem Monitoring Program. This technical memorandum contains analysis of nine years of data (2001-2009) from in situ fish belt transect and benthic habitat quadrat surveys conducted in and around the Virgin Islands National Park (VIIS) and the Virgin Islands Coral Reef National Monument (VICR). The purpose of this document is to: 1) Quantify spatial patterns and temporal trends in (i) benthic habitat composition and (ii) fish species abundance, size structure, biomass, and diversity; 2) Provide maps showing the locations of biological surveys and broad-scale distributions of key fish and benthic species and assemblages; and 3) Compare benthic habitat composition and reef fish assemblages in areas under NPS jurisdiction with those in similar areas not managed by NPS (i.e., outside of the VIIS and VICR boundaries). This report provides key information to help the St. John management community and others understand the impacts of natural and man-made perturbations on coral reef and near-shore ecosystems. It also supports ecosystem-based management efforts to conserve the region’s coral reef and related fauna while maintaining the many goods and ecological services that they offer to society.