Storm Surge Hazard in Canada   总被引：3，自引：2，他引：3  

Maurice Danard  Adam Munro  Tad Murty 《Natural Hazards》2003,28(2-3):407-434

Storm surges occur frequently in Canada mainlydue to extra-tropical cyclones (ETC'S) also referred to as winter storms. The hurricanes from the Gulf of Mexico can affect eastern Canada including Lakes Ontario and Erie regions, after they get modified and acquire some extra-tropical characteristics. Storm surges have occurred both on the Atlantic and Pacific coasts, in the Gulf of St.Lawrence, St.Lawrence Estuary, Bay of Fundy, Hudson Bay, James Bay, Northwest Passage, Beaufort Sea, the Great Lakes and other large lakes such as Lake Winnipeg.Squall lines which are embedded in the largerscale synoptic systems like the ETC'S could also generate storm surges (referred to as edge waves) in Lakes Huron, Erie and Ontario (edge waves are most prominent in Lake Michigan, but Canada has no territory touching this lake). The effect of climate change on storm surges in the Canadian water bodies could be two-fold. First, there may be some possible intensification of the weather systems and the associated wind fields resulting in bigger surges. Second, and probably even more relevant, is an east-west and north-south shift in the tracks of the weather systems, which could expose certain new areas to storm surge activity.A high priority for proper assessment of storm surge hazard is the production of maps showing inundation zones for storm surges that might occur in populated coastal areas. Such maps can be used to improve public awareness of tsunamis and for planning purposes (i.e., to reduce or avoid the risk).  相似文献   

On the ages of flood basalt events   总被引：2，自引：0，他引：2  

Vincent E Courtillot  Paul R Renne 《Comptes Rendus Geoscience》2003,335(1):113-140

We review available data constraining the extent, volume, age and duration of all major Phanerozoic continental flood basalts (CFB or traps) and oceanic plateaus (OP), together forming the group of large igneous provinces (LIP), going from the smallest Columbia flood basalts at ～16 Ma to the as yet ill-known remnants of a possible trap at ～360 Ma in eastern Siberia. The 16 traps (CFB and OP) reviewed form a rather unimodal distribution with an initial modal volume of the order of 2.5 Mkm³. Most provinces agree with a rather simple first order model in which volcanism may have lasted of the order of 10 Ma, often resulting in continental break-up, but where most of the volume was erupted in about 1 Ma or sometimes less. This makes CFBs/OPs (LIPs) major geodynamic events, with fluxes exceeding the total output of present day hot spots and even possibly exceeding over short times the entire crustal production of mid-ocean ridges. The proposed correlation between trap ages and the ages of several geological events, including mass extinctions and oceanic anoxia, is found to have improved steadily as more data have become available, to the point that the list of trap ages may coincide with many major divisions in the geological time scale. The four largest mass extinctions in the last 260 Ma coincide to the best resolution available with four traps, making a causal connection between the two through some form of catastrophic climatic perturbations the most likely hypothesis. The time sequence of LIPs appears to have been random and there is no robust evidence for long time trends in the corresponding crustal production rate over the last 260 Ma.  相似文献   

厄尔尼诺和拉尼娜事件循环演变过程的资料分析研究     

Chao Jiping  Yuan Shaoyu  Chao Qingchen  Tian Jiwei 《大气科学进展》2002,19(5):837-844

利用1955-2000年热带、副热带太平洋地区次表层温度距平资料,构造了温度距平极值深度分布曲面图,它很接近20°温度面的深度分布,因此有理由认为这一深度曲面很接近热带温跃层的深度面。在温度距平极值深度曲面上,分析了20世纪60年代后期以来所有El　Nino/La Nina事件正/负海温距平信号的分布和传播“轨迹”,发现如果以暖池次表层作为起点,则一般来说,暖水或冷水先是沿赤道极值深度面向东、向上传播或运动,到达赤道东太平洋海盆边界附近后,在那里停留几个月,然后转北运动,在北纬10度左右再折向西运动到西太平洋转向南返回到暖池,即在赤道北侧形成闭合回路。温度距平运动一圈需时2-4年。如果暖（冷）水的温度距平都很强,就会在2-4年的时间上出现两次相邻的El　Nino（La Nina）事件,但可能是由于大气或海洋环境条件不合适,温度距平的强度在运动过程中有时会减弱,就不能形成El　Nino（La Nina）事件,但暖（冷）水运动的“轨迹”仍可辨认。由于暖、冷水绕环路的运动交替出现,El Nino（La　Nina）爆发前,在赤道西太平洋出现正（负）距平信号的同时,在东太平洋北纬10度左右会有负（正）距平信号出现,并且当正（负）距平信号向东传播时,负（正）距平信号向西传播,在赤道上表现为2-4年间隔的El Nino（La Nina）交  相似文献   

东亚区域极端气候事件变化的数值模拟试验   总被引：62，自引：0，他引：62  

Gao Xuejie  Zhao Zongci  Filippo Giorgi 《大气科学进展》2002,19(5):927-942

使用ResCM2区域气候模式,嵌套澳大利亚CSIRO R21L9全球海气耦合模式,进行了温室效应（二氧化碳加倍）对东亚（主要是中国区域）极端气候事件影响的数值试验。控制试验的结果表明,区域模式能够较好地模拟中国区域的极端气候事件。对温室效应引起的它们的变化进行了信度检验,分析结果表明,温室效应将引起日最高和最低气温增加,日较差减小;使得高温天气增多,低温日数减少。降水日数和大雨日数在一些地区将增加。同时还会引起影响中国的台风活动的变化。  相似文献   

1991～1995年El Nio事件的数值模拟研究     

李清泉  丁一汇  赵宗慈 《应用气象学报》1997,(Z1)

该文利用一个简单的海－气耦合模式，从理论和数值试验方面研究了１９９１～１９９５年３次ＥｌＮｉｎｏ事件期间热带海洋中的热力和动力过程．利用１９９０年７月～１９９５年３月异常风应力强迫一个海洋模式，所得模拟结果和观测结果基本一致，可以清楚地看到３次暖过程．模拟结果的诊断分析表明，上述海表面温度明显而较快的变化主要是由水平平流作用、总上翻对距平温度垂直梯度的作用和热力阻尼决定的．西风异常在ＥｌＮｉｎｏ的发生、发展和衰亡过程中具有重要作用．  相似文献   

地质热事件—有机质—金属成矿作用的联系   总被引：7，自引：0，他引：7  

胡明安 《地质科技情报》1997,16(2):67-72

地质热事件引起有机质发生种种变化，也导致金属矿床的形成。地质热事件的性质不同，有机质变化的特点及成矿作用的类型也不尽相同。地质热事件与有机质的变化、金属成矿作用在发生时间、共生空间和形成原因诸方面均存在着密切的联系。  相似文献   

Chaos hides and generates order: An application to forecasting the next eruption of Vesuvius     

A. Palumbo 《Journal of Volcanology and Geothermal Research》1997,79(1-2)

The poissonian and non-fractal characters generally exhibited by the most intense natural events do not allow the application of the current exponential and power law long-term hazard predictive models, and have suggested searching for a new model. This has been set up also taking into account that the random sequence (representing disorder) of these events is linked to the duration of the stationary small ones (representing order). The model, proposed in terms of the orbit of a simple non-linear hazard function, simulates the large eruptions of Vesuvius quite well and permits estimation of the next subplinian eruption to occur there around A.D. 2030. A short range forecasting model based on the tidal triggering is also provided and discussed. When large tidally triggered M₂ term in the earthquakes at Vesuvius become significant at the 0.01 level the proposed long-term hazard model will yield a more accurate estimate of the above prediction.  相似文献   

青藏高原古地理环境研究   总被引：21，自引：2，他引：21  

李炳元  潘保田 《地理研究》2002,21(1):61-70

本文综述了最近 5 0年青藏高原古地理演化中一些基本问题研究进展。分析了中新世～上新世青藏古地理环境 ,高原在 3 6MaBP海拔不超过 10 0 0m ,此后强烈隆升。青藏高原最近三次冰期年代分别为 72 5～ 5 81、 2 89～ 136、 82～ 10kaBP ,冰期中不存在“大冰盖”。高原晚新生代重大古地理演化阶段和事件为 :38～ 2 2MaBP行星风系控制的热带 亚热带低地、 2 2～3 6MaBP古季风出现与主夷平面发育、 3 6～ 1 7MaBP高原强烈隆升与现代季风形成和现代河谷发育、 1 1～ 0 6MaBP高原抬升进入冰冻圈与大冰期出现、 0 15MaBP以来强烈隆升与高原内部干旱化。本文还讨论了高原古地理尚需深入研究的一些重大问题  相似文献   

Identifying elements of the plumbing system beneath Kilauea Volcano, Hawaii, from the source locations of very-long-period signals     

Javier Almendros  Bernard Chouet  Phillip Dawson  Timothy Bond 《Geophysical Journal International》2002,148(2):303-312

  相似文献   

天文地质学的发展与展望   总被引：2，自引：0，他引：2  

吴智勇  姜衍文 《地球科学进展》1996,11(1):24-29

天文地质学是天文学的地质学的边缘学科，是利用天文学的研究方法、观测资料的研究成果来探讨地球上各种地质现象成因和演化规律的科学，天文地质学的兴起是地球科学进入到成因研究阶段的产物，它的研究可望促进天文学和地质学的共同发展。本文简要介绍了这门新兴学科的发展过程、研究内容及发展趋势。  相似文献