基于LDM的乡镇雨量数据分中心的设计与实现

针对河南省乡镇雨量数据库服务器和雨量查询WEB服务器在有降水过程时经常会因访问压力过大而出现网站瘫痪的情况,根据乡镇雨量数据时效性高的特点,鉴于LDM系统在数据传输过程中的时效性和完整性,建立了基于LDM系统的乡镇雨量数据分中心.乡镇雨量数据分中心由雨量入库软件、乡镇雨量数据库和雨量查询网站构成.使用结果表明,雨量入库软件能及时将获取的雨量数据文件入库;查询(历史或实时)雨量时,访问乡镇雨量中心的速度要快于访问省局乡镇雨量网站的速度.     

中国近54年来夏季极端降水事件特征研究

利用1960~2013年中国6~8月无缺测的571站逐日降水资料,定义7个极端降水指数,研究中国夏季极端降水事件特征。结果表明:(1)极端降水事件空间分布存在明显的区域性差异,长江中下游地区、华南地区、西北地区表现为增加趋势,东北地区、华北地区、西南部分地区表现为减少趋势;时间分布表现出具有显著的年际和年代际变化特征,极端降水事件有增加趋势,在20世纪90年代初期有明显转折。(2)M-K检验表现出极端降水事件在20世纪90年代初发生突变,突变前(后)偏弱(强)。(3)极端降水指数周期振荡不完全一致,准15年周期振荡为主,其次是准7年周期,最强振动出现在1998年。(4)除持续干期指数外,其他极端降水指数间存在较好的相关性。     

广州地区雷暴过程云-地闪特征及其环境条件

应用雷电定位系统和高空观测资料并结合雷达回波资料, 对广州地区雷暴过程云-地闪特征进行分析, 并就有、无云-地闪出现的两组不同对流天气过程的环境条件进行了比较研究。结果表明:广州地区的雷暴过程以负的云-地闪为主, 负云-地闪所占比例在90%以上。云-地闪发生频率与雷暴系统强度演变有直接联系, 对于同一系统来说, 随着系统回波强度的增强, 云-地闪发生的频率也增高。但不同系统中, 云-地闪发生频率有很大不同, 回波强(弱)的对流系统并不意味着云-地闪发生的频率就高(低)。有云-地闪记录的对流天气过程具有更大的垂直切变、更高的相对风暴螺旋度以及更多的对流抑制能量, 云-地闪现象更易于出现在更加有组织和更强的对流系统中。研究还发现广州及周边城市区域对雷暴系统回波强度及云-地闪现象可能有影响, 两个典型个例分析表明, 雷暴系统移经城市区域时回波强度减弱, 云-地闪发生频率减小, 雷暴移过城市区域后, 强度可重新加强, 云-地闪发生频率增大。     

风暴生命史雷达特征量反演

从风暴演变各阶段物理特征出发, 基于多普勒雷达观测的三维反射率因子, 定义物理量———单体重力势能。结果表明:单体重力势能是一个能够简洁、客观描述风暴单体整体强度的物理量; 利用该物理量可描述单体生命史为发展和减弱两个基本过程; 单体重力势能大小有助于辨别风暴类型和强度。同时, 生成和分析了风暴单体演变各阶段的反射率因子垂直廓线, 分析表明:在30~150 km的雷达观测范围内, 风暴单体的反射率因子垂直廓线 (降水廓线) 及其随时间的变化能较好地揭示风暴的垂直结构和生命史演变特征, 但没有用重力势能那样简洁。     

New biostratigraphic data from the Cretaceous Bolinxiala Formation in Zanda, southwestern Tibet of China, and their paleogeographic and paleoceanographic implications

Planktonic foraminiferal fossil assemblages identified from the Bolinxiala Formation in Bolin, Zanda, southwestern Tibet of China, determine its age from latest Albian to Maastrichtian. The fossil contents of the Bolinxiala Formation allow its correlation with successions across a platform-to-basin transect of the Late Cretaceous Tethyan Himalaya passive margin. The ocean anoxic event at the Cenomanian–Turonian transition (OAE2) is located at the Whiteinella archaeocretacaea biozone in Zanda, but lithologically it is characterized by grey and bioturbated limestone, implying that during the OAE2 the shallow-water environments of the Tethyan Himalayan carbonate platform remained oxic. Paleogeographic reconstruction indicates that the Upper Cretaceous Oceanic Red Beds (CORBs) in southern Tibet are restricted to the slope and basinal environments but they are entirely missing in the shelf environments. This phenomenon suggests the formation of CORBs by oxidation of Fe(II)-enriched anoxic deep ocean seawater at the chemocline that separated the oxic surface ocean from anoxic deep ocean. For depositional environments above the chemocline, no CORBs would be expected. Because of the chemocline instability across different sedimentary basins, CORBs may be significantly diachronous, consistent with the occurrence of CORBs documented from global sedimentary basins.     

论中国大陆复杂和混杂的碰撞带构造

中国大陆碰撞带是以结构复杂、形成过程复杂和物质成分趋于混杂为主要特征的。在构造特征上 ,表现为由构造岩片和混杂岩带所组成 ,形成扇状褶皱和对冲型逆掩断层。在剖面上常形成楔状(鳄鱼式 )构造 ,在平面上可构成嵌入构造 ,它们其实是两个板块在碰撞过程中互相挤压、缩短与穿插的、一个统一的三维共轭剪切断裂系统中的不同表现形式。绝大多数中国大陆碰撞带都不是一次形成的 ,而是经历了多期次、活动性质各不相同的、复杂的形成过程。为了进一步提高碰撞带的研究水平 ,应该把碰撞带及其两侧的板块当作一个整体来进行综合研究 ,应该大力加强碰撞带周邻板块的沉积古地理、生物古地理、古地磁学、地球化学和构造变形、变位资料的系统研究。碰撞作用时期是元素、岩石和构造单元趋于混杂的时期 ,而不是有利于元素、物质的分异和富集。碰撞带的主碰撞期形成的矿床是十分有限的。笔者推测有 4种类型的矿床可能将成为西部古碰撞带地区找矿的主要目标。     

Ecological efficiency of coal cities in China: evaluation and influence factors

Natural Hazards - China’s energy consumption and environmental problems are becoming increasingly urgent issues as the nation’s economy continues its rapid development. A further...     

江西东坪石英脉型黑钨矿矿床地质特征、控矿因素及找矿标志

东坪钨矿床是近年在赣北地区新发现的首个超大型石英脉型黑钨矿矿床,位于长江中下游成矿带幕阜山地区东坪-香炉山钨矿找矿远景区东部。矿床赋矿层位为新元古代双桥山群安乐林组浅变质岩系,北东向断裂及其两侧的次级裂隙为区内主要控矿构造、容矿构造,隐伏的燕山晚期黑云母二长花岗岩为成矿岩体,与区内钨多金属成矿关系密切的为石英脉状硅化;两个矿带的钨矿体均产于成矿岩体外接触带,呈现了石英脉型黑钨矿矿床典型的"五层楼"分带特征,矿石工业类型主要为黑钨矿矿石;明确了构造和岩浆岩等主要控矿因素;总结出地表微细裂隙云英岩化-黄铁矿化蚀变带、含硫化物石英细脉带、石英脉、重砂及地球化学异常为区内主要找矿标志。     

溶液和温度作用下膨润土防水毯的渗透性能

以颗粒状和粉末状膨润土防水毯(GCLs)为对象,运用GDS (global digital systems)全自动渗透仪开展渗透试验,研究CaCl_2溶液作用下GCLs渗透性能的温度效应,初步探讨其机理。试验表明:当水化液为0.05mol/L的CaCl_2溶液时,两种GCLs渗透系数随温度升高呈现增大趋势;当水化液为去离子水时,颗粒状GCL渗透系数随温度升高而减小,粉末状GCL渗透系数随温度升高而增大。去离子水情况下,膨润土吸附结合水量随温度升高而减小;CaCl_2溶液作用下,吸附结合水量较去离子水情况大幅降低。当CaCl_2溶液浓度一定时,膨润土膨胀指数随温度升高而略有增大;当温度一定时,膨润土膨胀指数随CaCl_2溶液浓度升高而显著减小。以去离子水进行试验时:颗粒状和粉末状GCLs渗透系数随温度的变化主要影响因素为凝胶态蒙脱石数量,其次为流体黏滞系数和吸附结合水量;颗粒状GCLs膨润土孔隙结构越不均匀,凝胶态蒙脱石数量的影响就越显著,导致渗透系数随温度升高而减小、固有渗透率随温度升高显著降低。以CaCl_2溶液进行试验时,两种GCLs渗透系数随温度变化的主要受流体黏滞系数和吸附结合水量的影响,而受凝胶态蒙脱石数量的影响较小。孔隙溶液性质、温度和膨润土类型均对GCLs的防渗性能具有重要影响。     

Investigation of inner-basin variation: Impact of large reservoirs on water regimes of downstream water bodies

Large dams and reservoirs alter not only the natural flow regimes of streams and rivers but also their flooding cycles and flood magnitudes. Although the effect of dams and reservoirs has been reported for some vulnerable locations, the understanding of the inner-basin variation with respect to the effects remains limited. In this study, we analyse the Three Gorges Dam (TGD) built on the Changjiang mainstream (Yangtze River) to investigate the dam effect variations in the system of interconnected water bodies located downstream. We investigated the effect of flow alterations along the downstream river network using discharge time series at different gauging stations. The river–lake interactions (referring to the interactions between the Changjiang mainstream and its tributary lakes i.e. the Dongting and Poyang lakes) and their roles in modifying the TGD effect intensity were also investigated in the large-scale river–lake system. The results show that the water storage of the tributary lakes decreased after the activation of the TGD. Severe droughts occurred in the lakes, weakening their ability to recharge the Changjiang mainstream. As a consequence, the effect of the TGD on the Changjiang flow increase during the dry season diminished quickly downstream of the dam, whereas its impact on the flow decrease during the wet season gradually exacerbated along the mainstream, especially at sites located downstream of the lake outlets. Therefore, when assessing dam-induced hydrological changes, special attention should be paid to the changes in the storage of tributary lakes and the associated effects in the mainstream. This is of high importance for managing the water resource trade-offs between different water bodies in dam-affected riverine systems.