【作者】 柏春广；

【导师】 王建；

【作者基本信息】 南京师范大学 ， 自然地理学， 2003， 博士

【摘要】 风暴潮频率在全球气候变暖后的可能变化已引起了广泛的关注，而目前研究者们通过模拟与观测所获得的结论并不一致，基于此，本文从地质时期气候冷暖变化与热带气旋频率变化之间的关系对这一问题作了验证与探讨。 论文通过对位于江苏中部东台梁垛河闸的现代潮汐沉积的半个月的连续野外观测和定期观测以及对采集样品的粒度、落淤量、CaCO₃含量、磁化率、沉积纹层的数目、各层的厚度、颗粒的磨圆度等的变化情况的室内分析，认为江苏中部淤泥质潮滩沉积中的细砂泥互层层理是半日潮的产物，但由于滩面上水次数及层理保存状况等的影响，实际的层理数往往少于潮汐涨落次数。大、中、小潮期间形成的薄互层层理的物质组成及层理厚度存在明显的区别。潮滩上某些部位存在的厚互层层理则是半月天文潮的产物。通过对梁垛河闸9711号台风的现场观测并结合目前已有的风暴潮沉积的研究，分析了风暴潮沉积在构造和结构上的特点，从而建立了正常潮滩沉积中风暴潮沉积的识别标志，同时在野外观测中还发现即使在风暴潮期间，高潮滩上部仍存在只有淤积没有侵蚀的地带。 为区分风暴潮沉积是由台风引致还是由寒流或冷锋引致，对长期处于淤积状态的江苏中部大丰县斗龙港附近潮滩，采集了一年中每月小潮期间滩面表层泥样，并在启东茅家港滩面分别采集了6月、9月与12月的表层泥样，在实验室中，对这些样品进行孢粉等分析，认为在以粉砂、泥为主的潮滩沉积中，孢粉种类百分比，尤其是木本种类占孢粉总种类的百分比是判别季节性潮滩的重要指标，通过启东茅家港工程建设区淤积状况的观测记录对这一判别指标进行了验证。 对于古代风暴潮发生频率的分析，则需找到一个在某一时段内连续的或者相对连续的潮汐纹层剖面，经过多次的野外考察与比选，最后选择盐城上冈砖瓦厂为研究区，采集了W、M、E三个柱状沉积剖面，分析其岩性特征，找出其岩性对比关系，进行¹⁴C年代测定，并结合有孔虫和颗石藻的分析，判定研究的层段为全新世中期温暖期的潮滩沉积；分析其中的潮汐层理特征和沉积的周期性，取样分析沉积物的粒度、磁化率及孢粉特征；依据以泥为主的潮滩沉积剖面中每隔10～20厘米就有规律地出现的一层砂的分析结果，判定这一沉积特征为季节性的潮滩沉积旋回；观察沉积剖面中的风暴潮事件的记录状况，估算出剖面中记录的与9711号台风风暴潮强度相当的风暴潮的发生频率为2-4年一遇，而依据梁垛河闸多年的现代年最高潮位资料，采用耿贝尔曲线拟合法计算出的9711号台风所引致的风暴潮频率为12年一遇，即全新世中期温暖期的台风风暴潮的频率比现在大。据此推测全球变暖后，台风风暴潮的频率将会增加。更多还原

【Abstract】 The possible influence of the global warming to storm surge frequency has been one of the concerned questions at present for researchers. Some of them consider that the frequency will increase according to the results of observation and simulation, but some others don’t agree to it. To verify the speculated conclusions, the coastal storm surge frequency in middle Jiangsu province during the warm period ofmiddle Holocene is discussed in this thesis.To make clear the mechanism of silt-mud couplets in tidal flat, the flat of Dongtai, Jiangsu province is selected as a typical place for researching. Materials deposited in 8 sites in this place were collected continuously during half a month, and sediments in these sites were also sampled several times in a year. Field observation and lab experiments prove that the tidal sediments show both of daily and half-monthly periods. In a half-month cycle, the couplet’s thickness varied regularly from thinner to thicker, which corresponds to neap tide-spring tide.The field observation of the sediments of storm surge produced by No. 11 typhoon in 1997 shows that sedimentation rate of storm surge sediments are greater than that of normal astronomical tide sediments, and the grain size shows relative coarse with poor sorting. Vertical sequences of the storm sediment show parallel bedding and overlapped by hummock bedding. These characteristics provide good basis for building the index of storm surge deposit. In this field observation we also find an important fact that, even during storm surge period, high tidal flat can still be in sedimentation in some place, no erosion occurred.To tell the typhoon storm surges from cold wave storm surges, 12 monthly sedimentary samples are collected from the modern tidal flat surface at Dafeng, Jiangsu. Palynological analysis of these samples indicates that the seasonal palynological features of the tidal flat sediment are very obvious and some palynological indexes, such as taxonpercentage of Arboreal, Herbaceous pollen and spore, are good indicators to tell the seasonality of the tidal flat deposits. A sedimentary sequence formed between 1984-1994 is used to check this method. Checking result suggests that this method is acceptable and the Taxon percentage of Arboreal pollen is the best indicator for the seasonality of tidal flat deposits.Three column sections have been collected from Shanggang, Yancheng to analysis the storm surge frequency during the warm stage in middle Holocene. The results of lithology, dating age by 14C, foraminifera assemblages, calcareous nannofossils and palynological features indicate that the deposits were tidal flat deposits formed in the warm period of middle Holocene. The researches of the rhythmites of thicker silt layers and the characteristics of storm deposits show that the storm surge frequency is once every 2-4 years, yet modern storm surge with equivalent intensity occurs one time every 12 years. So the storm surge frequency in the warm period in middle Holocene is higher than that of today and we can speculate that the frequency will increase with global warming.更多还原