中国地震台网数字化改造的进展   总被引：12，自引：0，他引：12       下载免费PDF全文

刘瑞丰  吴忠良  阴朝民  陈运泰  庄灿涛 《地震学报》2003,25(5):535-540

介绍了九五期间（1996~2000年）中国地震台网数字化改造的进展和首都圈数字地震台网（1999~2001年）的建设情况，重点介绍了国家数字地震台网、区域数字地震台网和流动数字地震台网的台站分布、仪器配备和主要任务．   相似文献   

兰州地区深部电性结构的初步研究   总被引：1，自引：0，他引：1  

杨长福  林长佑  王书明  陈军营 《地震研究》2003,26(4):350-354

利用兰州地区现有的大地电磁资料，对该区的深部电性结构进行了初步研究。结果表明，兰州地区各地质构造单元的电性差异较明显，与区域构造有较好的对应性。  相似文献   

地震灾害现场救援搜索策略与搜索方法有关问题的讨论   总被引：13，自引：3，他引：13  

顾建华  陈维锋  郝清源 《国际地震动态》2003,(6):6-12

对地震灾害现场的搜索策略和搜索方法等有关问题进行了讨论，推荐了常用的搜索策略，对不同搜索方法的利弊进行了分析；对搜索方法的使用也做了讨论。通过讨论，文章就搜索分队的组成、任务、装备和部署等提出了建议。  相似文献   

地震视应力用于震后趋势快速判定的可能性   总被引：29，自引：0，他引：29  

陈学忠  王小平  王林瑛  张天中 《国际地震动态》2003,(7):1-4

对多次强震的地震视应力进行了计算，将各次强震的地震视应力的高低与强震发生后的后续地震的强度进行联系，探索它们之间的关系，进而提出将地震视应力用于强震震后趋势预测的可能性。对多次强震的地震视应力与其后续地震强度的关系的分析结果表明，低视应力的强震的后续地震的强度一般较低，即低视应力的强震发生后，震区发生较强的后续地震的可能性较小。  相似文献   

Characteristics of the atmospheric heat source and moisture sink over the Qinghai-Tibetan Plateau during the second TIPEX of summer 1998 and their impact on surrounding monsoon   总被引：2，自引：0，他引：2  

L. X. Chen  F. Schmidt  W. Li 《Meteorology and Atmospheric Physics》2003,83(1-2):1-18

Summary ?Using the data of 6 automatic heat balance observation (AWS) stations and a data set of 52 surface observation stations over the Qinghai-Tibetan Plateau (“the Plateau”) and surroundings, the horizontal distribution is studied of “apparent atmospheric heat sources” 〈Q ₁〉 and of “apparent atmospheric moisture sinks” 〈Q ₂〉. The AWS stations were established during the period May to August 1998 of the Tibetan Plateau Meteorological Experiment (second TIPEX) by a cooperation of China and Japan. For this period the Plateau mean of 〈Q ₁〉 is positive. Its value of 74 W/m² is a little greater than a climate value and than values from MONEX and the first TIPEX in 1979, respectively. Also the corresponding 〈Q ₂〉 is positive. Hence during that time the Plateau is a heat source and a moisture sink. A day-to-day change of 〈Q ₁〉 and 〈Q ₂〉 is more pronounced over the middle and east part of the Plateau than over the west part. Diagnostics accompanied by numerical simulations are used to study the daily relationship between 〈Q ₁〉 over the Plateau and the weather over China and Asia for this summer. The results suggest that 〈Q ₁〉 may affect precipitation over northern China and position of the west Pacific subtropical high. Abnormal southward retreat of this Pacific high seems to have caused the second flood over the middle and lower Yangtse river basin in July. Received May 20, 2001; revised February 2, 2002  相似文献   

Numerical simulation of a South China Sea typhoon Leo (1999)   总被引：6，自引：0，他引：6  

K.-H. Lau  Z.-F. Zhang  H.-Y. Lam  S.-J. Chen 《Meteorology and Atmospheric Physics》2003,83(3-4):147-161

Summary ?A South China Sea typhoon, Leo (1999), was simulated using the Penn State/NCAR mesoscale model MM5 with the Betts-Miller convective parameterization scheme (BMEX). The simulation had two nested domains with resolutions at 54 and 18 km, and the forecast duration was 36 hours. The model was quite successful in predicting the track, the rapid deepening, the central pressure, and the maximum wind speed of typhoon Leo as verified with reports from the Hong Kong Observatory (HKO). The structure of the eye, the eye wall, and the spiral convective cloud band simulated in the model are found to be comparable to corresponding features identified in satellite images for the storm, and also with those reported by other authors. A trajectory analysis was performed. Three kinds of trajectory were found: (1) spirally rising trajectories near the eye wall; (2) spirally rising/descending trajectories in the convective/cloud free belt; (3) straight and fast rising trajectories in a heavy convection zone along one of the cloud bands on the periphery of the tropical cyclone. Both the HKO and the U.S. Joint Typhoon Warning Center (JTWC) reported the rapid deepening of Leo started around 00 UTC 29 April. In the model, the eye was first formed in the lower troposphere, and it extended to the upper troposphere within a few hours. We speculate that the spin-up of cyclonic rotation in the low-level eye enhanced the positive vorticity along the low-level eye wall. The positive vorticity was then transported to the upper troposphere by convection, leading to an extension and growth of the eye into the upper troposphere. To examine the impact of convective parameterization scheme (CPS) on the simulation, the Grell scheme (GLEX) was also tested. The GLEX predicted a weaker typhoon with a wilder eye that extended not as high up in the upper troposphere as BMEX. The different structures of the eye between the BMEX and GLEX suggest that the mesoscale features of the eye are dependent on the convection. In other words, the vertical and horizontal distribution of convective heating is essential to the development and structure of the eye. Received December 18, 2001; accepted May 7, 2002 Published online: March 20, 2003  相似文献   

Influence of Changes in the Prevailing Synoptic Conditions on the Response of Aerosol Characteristics to Land- and Sea-Breeze Circulations at a Coastal Station     

K. Krishna Moorthy  Preetha S. Pillai  S. Suresh Babu 《Boundary-Layer Meteorology》2003,108(1):145-161

The changes in the response of near surfaceaerosol properties to land- and sea-breezecirculations, associated with the changes in the prevailing synoptic meteorological conditions, are examined for a tropical coastal station. Aerosol properties are nearly similar in both the breeze regimes (land and sea) during seasons of marine airmass while they are distinct during seasons of continental airmass. As the prevailing winds shift from continental to marine and the ambient weather changes from winter conditions to the humid monsoon season, the submicron mode, which dominated the aerosol mass-size distribution, is largely suppressed and the dominance of the super micron mode increases. During periods of continental air mass (winter), the aerosol loading is significantly higher in the land-breeze regime, (particularly in the submicron range) but as the winds shift to marine, the loading initially becomes insensitive to the breeze regimes and later becomes higher in the sea-breeze regime, particularly in the super micron range.  相似文献   

陆面过程模式的改进及其检验   总被引：11，自引：0，他引：11  

周锁铨  代刊  陈涛  屠其璞  陈万隆 《气象学报》2003,61(3):275-290

文中对陆面过程模式 (BATS)进行了改进 ,改进后的模式能较好地模拟地表物理量的年、季和日变化 ,它有两方面的特点 :采用热扩散方程模拟 7层土壤温度 ,模拟的温度可与实测值进行比较 ;在BATS的地表径流方案中 ,考虑了空间不均匀性的一般地表径流 (GVIC)过程 ,研究结果表明 :⑴模式能很好地模拟各层土壤温度的年、季和日变化。冬季土壤温度下层高于上层 ,而在夏季上层高于下层 ,这种上下层温度的转换时间大约在 4和 10月份 ,这与实测土壤温度的年变化非常一致。较为准确地模拟了各层土壤温度日变化的时滞效应。⑵用南京和武汉站的资料 ,将BATS地表径流方案模拟的地表水分分量与GVIC方案进行比较 ,BATS地表径流方案模拟的地表水分分量 ,与总水量的平衡相差较大 ,而GVIC模拟的效果相对较好 ,地表总水量基本上与降水总量达到了平衡  相似文献   

华南中尺度暴雨数值预报的不确定性与集合预报试验   总被引：50，自引：0，他引：50  

陈静  薛纪善  颜宏 《气象学报》2003,61(4):432-446

利用非静力MM5模式,分析了不同积云对流参数化方案对华南暖区暴雨数值预报的不确定性影响,进行了中尺度暴雨模式扰动集合预报试验。不同对流参数化方案的对流凝结加热引起不同的局地温度扰动,通过大气内部的热力动力过程,导致垂直速度的差异,进而影响网格尺度和次网格尺度降水时间、地点和强度。后续降水再通过凝结潜热释放形成新的扰动源。不同积云对流参数化方案还可引起扰动源能量传播方式不同,最终使模拟大气的动力和热力结构有差异。针对物理过程的不确定性,使用两种模式扰动方法构造集合预报扰动模式,第一种方法是随机组合不同积云对流参数化方案和边界层方案,第二种方法是扰动Grell积云对流参数化方案中主要参数振幅。集合预报结果表明,第一种方法的集合预报效果优于第二种方法,仅扰动参数振幅值似乎还不足以反映华南暴雨预报的不确定性。单一的确定性预报在暴雨落区和强度方面的可信度不稳定,集合产品能给华南暴雨过程提供更有用价值的指导预报,具有较高的应用价值。  相似文献   

利用数字图像处理技术提高地震剖面图像信噪比   总被引：1，自引：2，他引：1  

陈凤  李金宗  黄建明  李冬冬 《地球物理学进展》2003,18(4):758-764

提出了利用数字图像处理技术提高地震剖面信噪比的新方法，首先根据数字图像处理要求的格式，对地震剖面数据进行转换，得到地震剖面图像，分析了地震数据特点和初步地震图像的实验结果后，设计了新的预处理方法——“二维沿层滤波”，在此基础上，利用可以计算帧间运动速度及其变化都较大的改进的光流分析技术，计算出多幅地震剖面对应点的偏移量，然后应用图像积累技术对这多幅地震剖面进行积累，实现对三维地震数据体提高信噪比的处理，该方法充分利用了三维地震信息，不但可以提高整个数据体的信噪比，而且可以减少信号能量的损失，并保持原来的信号能量关系，使地震剖面的质量得到明显提高，为地震解释奠定良好的基础。  相似文献