THE STORM OF NOVEMBER 1826 IN THE CANARY ISLANDS: POSSIBLY A TROPICAL CYCLONE?     

JOSÉ BETHENCOURT‐GONZÁLEZ  PEDRO DORTA‐ANTEQUERA 《Geografiska Annaler: Series A, Physical Geography》2010,92(3):329-337

This work analyses a storm that occurred in the Canary Islands early in November 1826. Through a study based on historical climate data, some of the adverse effects of the storm are described and some of the possible causes are discussed. The main goal of this work is to establish an approximate reconstruction of this historical event which will allow us to compare it to a recent meteorological event that had a great impact on the archipelago: “Tropical Storm Delta”, in November 2005. Studying and reviewing the origin of the 1826 storm verifies the hypothesis that extremely violent perturbations have not only occurred in the Canaries on other occasions, but that these past events were also more intense and had more serious consequences than Delta. Therefore, the idea that other tropical perturbations have occurred in the region of the Canary Islands before Delta is presented.  相似文献   

天山北坡"20080826"超级单体的Doppler雷达资料分析     

赵俊荣  晋绿生  郭金强 《干旱区地理》2010,33(1)

利用石河子C波段Doppler雷达资料,对2008年8月26日下午至傍晚发生在天山北坡带中部石河子垦区全区性的一次强对流天气过程进行分析,结果表明:引起这次全区性的强对流天气风暴具有超级单体风暴的特征.这个超级单体南边出现明显的出流边界,并位于弧形回波带的南部.组合反射率因子垂直剖面图上呈现出有界弱回波区、回波悬垂和有界弱回波区左侧的回波墙,最大回波强度出现在沿着回波墙的一个竖直的狭长区域,其值达到65 dBZ、位于回波墙中上部.在中低层径向速度图上,弧形回波带的北部出现辐合区,其东南部呈现出一个中尺度气旋,旋转速度达到20 m/s,风暴顶为强烈辐散,正负速度差值达52m/s,其中3 000～6 000 m之间表现最为典型;与中气旋对应的回波强度和回波顶高以及垂直液态含水量都在暴雨中心附近达到最大.50dBz的回波顶高达9.8 km、宽度约10 km,60 dBz的回波顶高达到8.7 km、宽度约7 km,65 dBz的回波顶高达到8.0 km、宽度约2 km,垂直液态含水量从16:16的8 kg/m跃增到17:34的70 kg/m,该超级单体的移动方向在盛行风向的右侧约30°,属于右移风暴.  相似文献   

地电场观测中地电暴的识别   总被引：3，自引：0，他引：3  

张振文  赵卫星  杨桐  史红军 《东北地震研究》2010,26(2):40-47

本文主要利用吉林省地震局6个地电场台站的数据,对观测中常见的地电暴干扰的识别进行了详细的阐述,指出地电暴有别于雷电干扰和震兆异常。  相似文献   

“0801南方雪灾”水汽通量与降水关系的SVD分析   总被引：2，自引：0，他引：2  

杨玮  何金海  王佳  王盘兴 《热带气象学报》2011,(5):697-702

利用2008年1月10日—2月2日的NCEP/NCAR逐日风场、比湿、地面气压资料以及中国地面国际交换站194站的逐日降水资料,分析我国“0801南方雪灾”期间水汽通量场的特征,结果表明我国南方是整层水汽通量及其散度的高值区。用奇异值分解（SVD）方法,分析了水汽输送通量异常场和降水异常场之间的关系,揭示出两对统计显著且天气意义清晰的耦合模态。其中,第一对模态的方差贡献率为81.50%,相应左、右奇异向量时间系数的相关系数为0.80,主要描述源自孟加拉湾及南海的西南风水汽输送异常增强并在我国川、滇、黔交界处及粤、闽、赣一带辐合时,长江以南大部分地区多雨;第二对模态方差贡献率为8.80%,相关系数为0.64,主要描述当中国大陆东部有源自西太平洋的水汽输送异常增强并在广西-浙江沿线区域辐合时,长江中下游流域多雨,但华南三省（广西、广东和福建）少雨。   相似文献   

蒙古气旋引发辽宁沙尘暴天气过程的数值模拟   总被引：2，自引：2，他引：0  

刘宁微  马雁军  刘晓梅  周德平  王扬锋  王若男 《中国沙漠》2011,31(1):217-222

从一次发生在辽宁,由蒙古气旋引发的沙尘暴过程入手,利用数值模拟手段,结合常规气象观测资料,围绕蒙古气旋的动力、热力特征以及如何促成此次沙尘暴的发生、发展和维持进行探讨。结果表明,高空气流的辐散抽吸是此次过程的主要起沙动力机制,由蒙古国中部向东南方向延伸至韩国南部的副热带西风急流为此次辽宁沙尘暴过程提供了充足的沙源。此外,蒙古气旋内部的垂直环流与控制辽宁地区的冷平流对此次沙尘暴和降温过程具有一定的触发与维持作用。  相似文献   

中国沙尘暴发生的气象危险度研究   总被引：5，自引：3，他引：2  

罗敬宁  郑新江  朱福康  咸迪  杨维西  屠志方  李梦先 《中国沙漠》2011,31(1):185-190

引入沙尘暴发生的气象危险度的概念,通过数学模型、实例计算和数据分析, 得到了定量的沙尘暴发生危险程度评价指标,并绘制了中国沙尘暴发生的气象危险度区划图。结果表明: ①新疆南部地区沙尘暴发生的危险度最大（气象危险度最高达到4级）,其次是内蒙古西部、甘肃北部部分地区（气象危险度最高达到3级）。 ②大风是沙尘暴发生的重要驱动力,每次沙尘天气过程中都伴随较强的风速,但是,沙尘暴天气过程越强,风速越大的现象并不明显。 ③通过绘制中国沙尘暴发生的气象危险度区划图,可以更好地刻画沙尘暴发生危险程度的空间分布特征,同时也为沙尘暴预报和灾害评价提供了重要参考。  相似文献   

纹层状细粒碳酸盐岩成因:以贵州习水吼滩剖面下奥陶统为例          下载免费PDF全文

孙永超  刘建波 《古地理学报》2016,18(5):743-758

纹层是组成层理的基本单位,既可以是低能深水沉积环境的产物,也可能形成于高能环境中。在受风暴影响的区域,微小的泥质颗粒能够在流动过程中发生絮凝形成絮粒并沉积下来形成纹层。贵州习水吼滩剖面下奥陶统桐梓组碳酸盐岩纹层发育,纹层中风暴沉积构造丰富,包括风暴侵蚀面和渠模等。基于细致的野外观察和室内沉积学研究,将在风暴作用影响下形成的纹层划分为5个类型:平行厚纹层、单向交错薄纹层、平行薄纹层、波状厚纹层和水平厚纹层。采用EDS元素面扫描方法,发现亮、暗纹层中都含有铝、硅和镁元素且分布都比较均匀,而暗纹层所含黏土矿物稍多,所以暗纹层中3种元素的含量比亮纹层的稍高。利用开尔文—赫姆霍兹不稳定性解释了亮、暗纹层的形成机制,即絮粒与未发生絮凝的微小颗粒在开尔文—赫姆霍兹不稳定性作用下交替沉积,其中以絮粒为主的纹层更容易发生重结晶形成亮纹层。根据各纹层不同的垂向结合序列划分出3种风暴序列,且从Ⅰ型到Ⅲ型风暴作用逐渐减弱。  相似文献   

Putting a spin on palaeotsunami deposits          下载免费PDF全文

James Goff  Bruce McFadgen  Catherine Chagué‐Goff  Kazuhisa Goto  Scott Nichol 《地球表面变化过程与地形》2016,41(9):1293-1296

Palaeotsunami research is a relatively young discipline and while considerable progress has been made in identifying the evidence of past events there are still difficulties on occasion in differentiating between palaeotsunami and palaeostorm deposits. This has tended to focus debate on the similarities and differences between deposits laid down by the two differing processes at the expense of alternative hypotheses. Although coastal research in New Zealand a decade ago drew attention to high elevation coarse sediment deposits laid down by waterspouts, it was largely ignored by the research community. Re‐analysis of a possible palaeotsunami deposit on a nearshore island in New Zealand, however, highlights the likelihood that this deposit, and perhaps many similar coastal ones, may have been laid down by waterspouts. In essence, the palaeotsunami–palaeostorm debate can no longer ignore waterspouts as an alternative hypothesis, but only time will tell how significant a contribution waterspouts have made to catastrophic coastal sedimentation. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Morphological response of a barrier island system on a catastrophic event: the AD 1634 North Sea storm          下载免费PDF全文

Mikkel Fruergaard  Aart Kroon 《地球表面变化过程与地形》2016,41(3):420-426

The AD 1634 North Sea storm is one of the most catastrophic storms along the Wadden Sea coast of Denmark. In this study we show how pre‐1634 storm morphology exerted a strong control on the resulting post‐storm coastal morphology. Erosional responses associated with the storm were barrier breaching, dune scarping and shoreface erosion and accretionary responses were washover deposition, shoreface healing and barrier‐island formation. Local sediment sources appeared to have a particularly strong influence on post‐storm coastal evolution and allowed a very rapid formation of a barrier shoal which resulted in several kilometres of coastal progradation. Sediment budgets suggest that formation of the barrier shoal was possible, but the sediment transport rates in the decades after the 1634 storm, must have been two to three times higher than present‐day rates. The study demonstrates that catastrophic storms are capable of moving large amounts of sediments over relatively short time‐periods and can create barrier shoals, whereas moderate storms mostly rework the shoal or barrier and create more local erosion and/or landward migration. Catastrophic storms substantially influence long‐term and large‐scale coastal evolution, and storms may positively contribute to the sediment budget and promote coastal progradation in coastal areas with longshore sediment convergence. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Geomorphological control on boulder transport and coastal erosion before,during and after an extreme extra‐tropical cyclone          下载免费PDF全文

Larissa A. Naylor  Wayne J. Stephenson  Helen C. M. Smith  Oliver Way  James Mendelssohn  Andrew Cowley 《地球表面变化过程与地形》2016,41(5):685-700

Extreme wave events in coastal zones are principal drivers of geomorphic change. Evidence of boulder entrainment and erosional impact during storms is increasing. However, there is currently poor time coupling between pre‐ and post‐storm measurements of coastal boulder deposits. Importantly there are no data reporting shore platform erosion, boulder entrainment and/or boulder transport during storm events – rock coast dynamics during storm events are currently unexplored. Here, we use high‐resolution (daily) field data to measure and characterize coastal boulder transport before, during and after the extreme Northeast Atlantic extra‐tropical cyclone Johanna in March 2008. Forty‐eight limestone fine‐medium boulders (n = 46) and coarse cobbles (n = 2) were tracked daily over a 0.1 km² intertidal area during this multi‐day storm. Boulders were repeatedly entrained, transported and deposited, and in some cases broken down (n = 1) or quarried (n = 3), during the most intense days of the storm. Eighty‐one percent (n = 39) of boulders were located at both the start and end of the storm. Of these, 92% were entrained where entrainment patterns were closely aligned to wave parameters. These data firmly demonstrate rock coasts are dynamic and vulnerable under storm conditions. No statistically significant relationship was found between boulder size (mass) and net transport distance. Graphical analyses suggest that boulder size limits the maximum longshore transport distance but that for the majority of boulders lying under this threshold, other factors influence transport distance. Paired analysis of 20 similar sized and shaped boulders in different morphogenic zones demonstrates that geomorphological control affects entrainment and transport distance – where net transport distances were up to 39 times less where geomorphological control was greatest. These results have important implications for understanding and for accurately measuring and modelling boulder entrainment and transport. Coastal managers require these data for assessing erosion risk. © 2016 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.  相似文献