A computer model for forecasting ocean wave parameters at specific sites around the the New Zealand coast     

A. K. Laing 《新西兰海洋与淡水研究杂志》2013,47(4):517-533

An applications model for forecasting frequency‐directional wave spectra at any appropriately specified site is described. There are two stages to the calculations. Firstly, a spectrum is calculated based on results at nearby gridpoints from an ocean wave prediction model. This is then adjusted to make the spectrum consistent with the local wind history. Verifications of the model are made at sites off Cape Egmont and Great Barrier Island, North Island, New Zealand. These give encouraging results for the shape of the frequency spectrum, with reasonable skill evident in the energetic parts of the spectrum. The significant wave heights also agree well, with the model estimates explaining two thirds of the measured variance.  相似文献   

西藏帕里湖卫星遥感监测     

王治华  徐起德 《山地学报》2009,27(2)

为查明2004年和2005年夏季在中印边界附近发生的滑坡堰塞湖溃坝灾害,采用高分辨率为主的多时相卫星图像和“数字滑坡”技术对帕里河中段从形成堰寒湖到溃坝的整个过程进行了监测。监测结果表明位于喜马拉雅山脉西段的帕里湖为高原山地萎缩湖盆,滑坡筑坝形成堰塞湖至溃坝可分为4个阶段,估算溃坝前湖面的最大高程、最大面积和最大水繁分别达3907m、1．75km^2和6144×10^4 m^3,2005-06-26溃坝的下泄洪水量为3738×10^4 m^3。预测未来汛期帕里湖下游仍然存在崩塌滑坡活动及短暂堵江形成堰塞湖的可能性,但其规模将大多小于2004-2005年的灾害。在本次遥感监测的基础上,定期进行遥感监测,当帕里湖水面面积≥1．6km^2时,即通知下游作好撤离等避灾准备,是目前最经济有效的预警防灾措施。  相似文献   

Sediment source changes over the last 250 years in a dry-tropical catchment, central Queensland, Australia   总被引：2，自引：0，他引：2  

Andrew O. Hughes  Jon M. Olley  Jacky C. Croke  Lucy A. McKergow 《Geomorphology》2009,104(3-4):262-275

Rivers draining to the Great Barrier Reef are receiving increased attention with the realisation that European land use changes over the last  150 years may have increased river sediment yields, and that these may have adversely affected the reef environment. Mitigation of the effects associated with such changes is only possible if information on the spatial provenance and dominant types of erosion is known. To date, very few field-based studies have attempted to provide this information. This study uses fallout radionuclide (¹³⁷Cs and ²¹⁰Pb_ex) and geochemical tracing of river bed and floodplain sediments to examine sources over the last  250 years for Theresa Creek, a subcatchment of the Fitzroy River basin, central Queensland, Australia. A Monte Carlo style mixing model is used to predict the relative contribution of both the spatial (geological) sources and erosion types. The results indicate that sheetwash and rill erosion from cultivated basaltic land and channel erosion from non-basaltic parts of the catchment are currently contributing most sediment to the river system. Evidence indicates that the dominant form of channel erosion is gully headcut and sidewall erosion. Sheetwash and rill erosion from uncultivated land (i.e., grazed pasture/woodland) is a comparatively minor contributor of sediment to the river network. Analysis of the spatial provenance of floodplain core sediments, in conjunction with optical dating and ¹³⁷Cs depth profile data, suggests that a phase of channel erosion was initiated in the late nineteenth century. With the development of land underlain by basalt in the mid-twentieth century the dominant source of erosion shifted to cultivated land, although improvements in land management practices have probably resulted in a decrease in sediment yield from cultivated areas in the later half of the twentieth century. On a basin-wide scale, because of the limited spatial extent of cultivation, channel sources are likely to be the largest contributor of sediment to the Fitzroy River. Accordingly, catchment management measures focused on reducing sediment delivery to the Great Barrier Reef should focus primarily on decreasing erosion from channel sources.  相似文献   

Internal structure of a barrier beach as revealed by ground penetrating radar (GPR): Chesil beach, UK   总被引：1，自引：0，他引：1  

Matthew R. Bennett  Nigel J. Cassidy  Jeremy Pile 《Geomorphology》2009,104(3-4):218-229

Chesil Beach (Dorset) is one of the most famous coastal landforms on the British coast. The gravel beach is over 18 km long and is separated for much of its length from land by a tidal lagoon known as The Fleet. The beach links the Isle of Portland in the east to the mainland in the west. Despite its iconic status there is little available information on its internal geometry and evolutionary history. Here we present a three-fold model for the evolution of Chesil Beach based on a series of nine ground penetrating radar (GPR) traverses located at three sites along its length at Abbotsbury, Langton Herring and at Ferry Bridge. The GPR traverses reveal a remarkably consistent picture of the internal structure of this barrier beach. The first phase of evolution involves the landward transgression of a small sand and gravel beach which closed upon the coast leading to deposition of freshwater peat between 5 and 7 k yr BP. The second evolutionary phase involves the ‘bulking-out’ of the beach during continued sea level rise, but in the presence of abundant gravel supplied by down-drift erosion of periglacial slope deposits. This episode of growth was associated with a series of washover fans which accumulated on the landward flank of the barrier increasing its breadth and height but without significant landward transgression of the barrier as a whole. The final phase in the evolution of Chesil Beach involves the seaward progradation of the beach crest and upper beach face associated with continued sediment abundance, but during a still-stand or slight fall in relative sea level. This phase may provide further evidence of a slight fall in relative sea level noted elsewhere along the South Coast of Britain and dated to between 1.2 and 2.4 k yr BP. Subsequently the barrier appears to have become largely inactive, except for the reworking of sediment on the beach face during storm events. The case study not only refines the evolutionary picture of Chesil Beach, but illustrates the importance of the subtle interplay between relative sea level and sediment supply in the evolution of a barrier system. In addition, it also illustrates the potential of GPR in resolving the evolutionary history of gravel-rich coastal landforms such as Chesil Beach.  相似文献   

Water quality and coral bleaching thresholds: Formalising the linkage for the inshore reefs of the Great Barrier Reef, Australia   总被引：1，自引：0，他引：1  

Scott A. Wooldridge 《Marine pollution bulletin》2009,58(5):745-751

The threats of wide-scale coral bleaching and reef demise associated with anthropogenic climate change are widely known. Here, the additional role of poor water quality in lowering the thermal tolerance (i.e. bleaching ‘resistance’) of symbiotic reef corals is considered. In particular, a quantitative linkage is established between terrestrially-sourced dissolved inorganic nitrogen (DIN) loading and the upper thermal bleaching thresholds of inshore reefs on the Great Barrier Reef, Australia. Significantly, this biophysical linkage provides concrete evidence for the oft-expressed belief that improved coral reef management will increase the regional-scale survival prospects of corals reefs to global climate change. Indeed, for inshore reef areas with a high runoff exposure risk, it is shown that the potential benefit of this ‘local’ management imperative is equivalent to ∼2.0-2.5 °C in relation to the upper thermal bleaching limit; though in this case, a potentially cost-prohibitive reduction in end-of-river DIN of >50-80% would be required. An integrated socio-economic modelling framework is outlined that will assist future efforts to understand (optimise) the alternate tradeoffs that the water quality/coral bleaching linkage presents.  相似文献   

Purpose,policy, and practice: Intent and reality for on-ground management and outcomes of the Great Barrier Reef Marine Park     

《Marine Policy》2017

Notwithstanding a complex array of international, national, and local policies designed to protect biodiversity and manage human activities, the condition of Australia's Great Barrier Reef has been deteriorating. This trend indicates that policy settings are inadequate or the right policies have been prescribed but not effectively implemented. This study aimed to determine which policies influenced on-ground management of the Great Barrier Reef World Heritage Area and Marine Park, how they were implemented, and the challenges encountered by practitioners in applying policies. The research required content analysis of policy instruments relevant to various jurisdictional levels, and surveys and interviews with 19 key informants across jurisdictions and agencies. This study found that policy intent is not automatically translated into practice: international agreements are interpreted and reinterpreted along the policy pathway to on-ground management and, consequently, the aspirations of these agreements can be frustrated and their effectiveness diluted. Due to limits of jurisdictional responsibility, practitioners within the Great Barrier Reef Marine Park Authority are constrained in influencing key factors that impact on their capacity to address threats and manage outcomes. The major policy gap affecting management outcomes was the absence of a mechanism with which to manage cumulative impacts responsible for deterioration of key ecosystem processes and biodiversity. These findings highlight that effective policy implementation is a challenging task, limited by gaps between intentions and outcomes, inconsistencies, and conflicting agendas. An improved understanding of the policy implementation process and the policy-practitioner relationship is essential to enhancing links between policy and on-ground management.  相似文献   

TOGA-COARE IOP期间赤道西太平洋海表壁垒层的研究     

徐炳荣  林传兰  董如洲  厉善华 《海洋与湖沼》1998,29(6):632-639

根据“向阳红五号”调查船于１９９２－１９９３年ＴＯＧＡ－ＣＯＡＱＲＥ（Ｔｒｏｐｉｃａｌ Ｏｃｅａｎ ａｎｄ Ｇｌｏｂａｌ Ａｔｍｏｓｐｈｅｒｅ－Ｃｏｕｐｌｅｄ Ｏｃｅａｎ Ａｔｍｏｓｐｈｅｒｅ Ｒｅｓｐｏｎｓｅ Ｅｘｐｅｒｉｍｅｎｔ）强化观测期（ＩＯＰ）期间,在赤道西太平洋观测到的ＣＴＤ,海面气象等资料,计算了海表ｂａｒｒｉｅｒ ｌａｙｅｒ（壁垒层）厚度。并对该海区壁垒层厚度的变化特征及机制作初步  相似文献   

云南旅游业可持续发展障碍及对策   总被引：1，自引：0，他引：1  

明庆忠  管宁生 《热带地理》1998,18(4):350-355

针对云南旅游业发展的实际,指出了云南旅游业可持续发展存在着旅游业无烟工业,旅游业是抵投入,高产出的劳动密集型产业和旅游资源可永久利用等思想意识障碍,从业人员和管理人员素质低以及旅游者注重保护等行为障碍,缺乏统一规划引导和多头管理等管理体制上的障碍,还有生态环境障碍等,进而提出了要认真做好规划布局和分期分批地规范有序开发,提高公众认识水平,做好环境审计评价和管理工作,对旅游投资管理者进行资质审查与分  相似文献   

Oil and gas wells and their integrity: Implications for shale and unconventional resource exploitation     

《Marine and Petroleum Geology》2014

Data from around the world (Australia, Austria, Bahrain, Brazil, Canada, the Netherlands, Poland, the UK and the USA) show that more than four million onshore hydrocarbon wells have been drilled globally. Here we assess all the reliable datasets (25) on well barrier and integrity failure in the published literature and online. These datasets include production, injection, idle and abandoned wells, both onshore and offshore, exploiting both conventional and unconventional reservoirs. The datasets vary considerably in terms of the number of wells examined, their age and their designs. Therefore the percentage of wells that have had some form of well barrier or integrity failure is highly variable (1.9%–75%). Of the 8030 wells targeting the Marcellus shale inspected in Pennsylvania between 2005 and 2013, 6.3% of these have been reported to the authorities for infringements related to well barrier or integrity failure. In a separate study of 3533 Pennsylvanian wells monitored between 2008 and 2011, there were 85 examples of cement or casing failures, 4 blowouts and 2 examples of gas venting. In the UK, 2152 hydrocarbon wells were drilled onshore between 1902 and 2013 mainly targeting conventional reservoirs. UK regulations, like those of other jurisdictions, include reclamation of the well site after well abandonment. As such, there is no visible evidence of 65.2% of these well sites on the land surface today and monitoring is not carried out. The ownership of up to 53% of wells in the UK is unclear; we estimate that between 50 and 100 are orphaned. Of 143 active UK wells that were producing at the end of 2000, one has evidence of a well integrity failure.  相似文献   

CBERS-02B星数据在5•12汶川地震灾害监测中的应用——以唐家山堰塞湖动态监测为例     

王志一  甘甫平  李贤庆  孙瑜  王振坤 《国土资源遥感》2009,20(1):89-92

利用CBERS-02B星获取的多时相CCD数据，采用人机交互方式对唐家山堰塞湖进行水体信息提取,对湖泊面积变化进行统计分析，从而了解湖面的动态变化及发展趋势，为地质灾情评估与灾害防治提供了定量化依据。  相似文献