Vertical Observations and Analysis of PM2.5, O3, and NOx at Beijing and Tianjin from Towers during Summer and Autumn 2006

During the period between 18 August and 22 September 2006, an ultraviolet photometric O3 analyzer, a NO-NO2-NOx chemiluminescence analyzer, and a quartz micro-oscillating-scale particle concentration analyzer were simultaneously used for monitoring at three different heights each at Beijing (325-m tower) and Tianjin (255-m tower). These towers belong to the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences (CAS) and to the Tianjin Municipal Meteorological Bureau, respectively. These measurements were used to continuously measure the atmospheric O3 and NOx volume-by-volume concentrations and the PM2.5 mass concentration within a vertical gradient. When combined with meteorological data and information on the variation of vertical characteristics of the various atmospheric pollutants in the two cities, analysis shows that these two cities were seriously polluted by both PM2.5 and O3 during summer and autumn. The highest daily-average concentrations of PM2.5 near the ground in Beijing and Tianjin reached 183 μg m-3 and 165 μg m-3, respectively, while the O3 concentrations reached 52 ppb and 77 ppb, and NOx concentrations reached 48 ppb and 62 ppb for these two cities, respectively. The variations in the daily-average concentrations of PM2.5 between Beijing and Tianjin were demonstrated to be consistent over time. The concentrations of PM2.5 measured in Beijing were found to be higher than those in Tianjin. However, the overall O3 concentrations near the ground in Tianjin were higher than in Beijing. NOx concentrations in Tianjin were consistently lower than in Beijing. It was also found that PM2.5 pollution in Beijings atmosphere may also be affected by the pollutants originating in and delivered from Tianjin, and that Ti     

民勤干旱区冬季浓雾形成的边界层条件分析

利用民勤县气象站过程地面小时观测资料、逐日08时和20时每隔50 m探空资料和NECP再分析资料,对2015年11月9—13日出现在干旱区民勤县的一次罕见浓雾天气过程进行了研究分析。结果表明:前期降水后地面相对湿度增大,为大雾形成提供了必要的水汽条件,稳定的高低层环流配置提供了大雾形成的稳定层结和弱风条件。雾层的厚度和强度与近地面逆温层的强度和厚度、边界层高度、水汽垂直运动以及夜间地气温差绝对值密切相关,边界层高度越高,逆温层越厚,雾层越厚;逆温层越强,夜间地气温差绝对值越小,雾层越强。高空环流形势稳定少动,近地层强逆温层、稳定等温层以及饱和湿层长时间维持,导致此次大雾强度和持续时间异常罕见。     

云南剑川近场横波特征及其与构造的关系

通过对1982年7月3日云南剑川Ms5．4级地震的余震震群近场记录的研究，为该地区存在横波分裂现象及上部地壳存在裂隙各向异性提供了直接的证据．剑川地区地震记录波形复杂，纵、横波视周期差异较大．横波快波偏振主要集中在NE45°和NW55°两个方向．7月20日ML4．8级强余震前后横波快波偏振取向变化显著，各台横波偏振方向震前彼此相对独立；震后整体上趋于有序．前者反映了地震发生前由于震源区应力集中在附近空间形成的应力分布的差异；后者显示出地震发生后由于震源区集中应力的释放带来的上述应力差异在一定空间范围的解除．该结果表明震源附近地区地震横波分裂特征不仅携带着地震处于相对平静期应力场的静态信息，而且也携带着地震发生前后应力场时、空动态变化的重要信息．文中还讨论了剑川地区构造对S波分裂的影响．     

台风“威马逊”近海加强及引发广西异常暴雨分析

利用MICAPS常规资料、中尺度自动站资料以及NCEP、ECMWF等数值预报产品资料,采用天气学诊断分析方法,对1409号超强台风"威马逊"近海加强、造成广西异常暴雨的成因进行分析。结果表明:1"威马逊"经过的海域温度异常偏高,西南季风急流增强,以及垂直风切变小,有利于"威马逊"近海加强;2"威马逊"与季风急流在海南文昌近海相遇,促使台风中心附近潜热能持续增大,暖心结构更趋于完整,是"威马逊"强度突然加强的重要原因;3充沛的水汽输送和水汽辐合、强烈的上升运动是造成"威马逊"异常暴雨的重要原因。     

定量模拟分析船体与空气枪间的安全距离

海洋地震勘探过程中,水中放置的空气枪与船体之间须保持一定安全距离,否则引起船载设施和仪器剧烈抖动,影响船舶设施和仪器的安全运行,甚至更严重情况下,有可能造成船体的损坏.利用海水压力脉冲与船体受到的冲击压力关系,结合建立的空气枪震源子波模型模拟近场震源子波,可计算出船体与空气枪间的安全距离.研究结果表明,根据震源子波模型模拟的近场子波主峰值,总容量150in3G枪、300 in3相干G枪及760 in3相干G枪的安全距离分别为3.90、6.57 m和9.13 m.由此可知,空气枪与船体间距离只有大于安全距离,才能避免船体大的振动或设备免遭损害,保证海洋地震勘探有效、安全的进行.     

"百合"台风近海加强成因分析

利用卫星云图、常规观测资料对“百合”台风减弱为低压后在台湾海峡南部海面强度再次加强，又发展成强热带风暴的过程分析诊断结果表明：“百合”台风近海加强的主要原因是台风上层强辐散流场的叠加，加强了台风环流的垂直上升运动；台湾海峡南部的暖洋区的增暖增湿、中低层辐合流场的加强和低层适度冷空气的侵入对台风的加强也起了一定的作用．     

灌河口潮间带及其入海河段秋季大型底栖动物生态学研究

2011年10月对灌河口及其入海河段中潮带进行了11个站位的大型底栖动物调查,共发现大型底栖动物10种,均为软体动物。潮间带优势种为光滑河篮蛤(Potamocorbula laevis),总平均丰度为92个/m2,总平均生物量为20.9 g/m2;入海河段优势种为中华拟蟹守螺(Cerithidea sinensis),总平均丰度为180个/m2,总平均生物量为52.5 g/m2。与邻近海域相比,大型底栖动物物种数、丰度、H’等都较低。相关性分析表明有机污染物敌敌畏、OCPs、SVOCs和重金属镉、汞、锌和总铬的浓度对生物量、丰度和H’有着显著或较大影响。研究表明,灌河沿岸4个化学工业园的排污及沿岸码头建设等对该海域产生了较大的人为扰动,已不适宜部分大型底栖动物的生存,需进行跟踪调查监测及时制定该海域生态保护、修复规划。     

基阶和高阶瑞雷波频散曲线反演对比分析

通过瑞雷波频散曲线反演,可以建立近地表横波速度模型。瑞雷波频散曲线具有多个模态,一般情况下,基阶模态是具有最大能量的模态。目前对瑞雷波频散曲线的反演大多数是基于基阶模态,对于高阶模态的反演比较少。通过对基阶和高阶瑞雷波频散曲线反演对比分析,认为高阶模态和基阶模态频散曲线反演有比较好的一致性趋势,相对而言高阶模态频散曲线反演的横波速度比基阶要高;高阶和基阶模态能量加权反演,不仅保留了频散曲线基阶模态能量强,勘探深度深的特点,而且对浅层低速层也具有更好的响应,可有效提高反演的精度。     

Base isolation for near‐fault motions

Three analytical studies of base‐isolated structures are carried out. First, six pairs of near‐fault motions oriented in directions parallel and normal to the fault were considered, and the average of the response spectra of these earthquake records was obtained. This study shows that in addition to pulse‐type displacements, these motions contain significant energy at high frequencies and that the real and pseudo‐velocity spectra are quite different. The second analysis modelled the response of a model of an isolated structure with a flexible superstructure to study the effect of isolation damping on the performance of different isolation systems under near‐fault motion. The results show that there exists a value of isolation system damping for which the superstructure acceleration for a given structural system attains a minimum value under near‐fault motion. Therefore, although increasing the bearing damping beyond a certain value may decrease the bearing displacement, it may transmit higher accelerations into the superstructure. Finally, the behaviour of four isolation systems subjected to the normal component of each of the near‐fault motions were studied, showing that EDF type isolation systems may be the optimum choice for the design of isolated structures in near‐fault locations. Copyright © 2001 John Wiley & Sons, Ltd.     

上海地区地磁转换函数变化及其与近震的关系

计算分析了上海地区佘山台１９７７年１月－１９８６年１２月和崇明台１９８３年１月－１９８９年９月的地磁周期Ｔ＝９－２００ｍｉｎ的复转换函数Ａ的模│Ａ│，总方差σｚ和帕金森林矢量或韦氏矢量，并将其在上海地区９０－３００ＫＭ范围内４次５－６级近震发生时的烨变化进行了研究。结果表明周期为１５、２０和３５ｍｉｎ的│Ａ│和σｚ值在震前明显异常，帕金森矢量或韦氏矢量在震前指向震中，震后回到正常位置，在此基础上，