2014年一次渝东北大暴雨天气成因诊断分析

采用常规观测资料、NCEP 1°×1°再分析资料及自动站、SWAN、风廓线等资料对2014年8月31日至9月1日渝东北地区出现的一次大暴雨天气进行诊断分析,结果表明：①持续性的强降水产生于有利的环流形势下。华南地区副热带高压稳定维持,副高北侧高空低槽缓慢东移,与低空切变线形成了持续性的大尺度强迫作用,使得强降水长时间维持。②强西南暖湿气流与偏东冷流在渝东北地区交汇,锋生作用显著,暴雨期间锋区呈准静止状态,锋区对流层中低层显著的θse差动平流有利于锋区对流性不稳定增强。③风廓线雷达显示暴雨期间西南低空急流显著增强,1～3 km高度低空急流维持超过8 h,最大风速超过18 m〖DK〗·s-1,并存在显著的高空辐散、低空辐合。④地形对降水的增幅作用显著。TREC风场显示大巴山南麓维持西南气流,风向与山脉走向近乎垂直,地形的强迫抬升作用加大了山前降水,形成了与山脉走向基本一致的大暴雨区。     

长治地区干旱分析和降水预报

对长治、沁县等11个测站1960~2000年3~8月逐月降水资料进行统计分析,根据旱月出现个数、发生月份、干旱程度、持续时间和对农业生产危害程度,将长治地区的春旱和夏旱各分6个等级,从中寻找春夏两季干旱发生的规律。利用最优子集回归方法建立了春夏两季降水预报方程,对长治地区春夏两季降水定量预报进行了初步研究,并初步确定了影响长治地区春夏两季降水的主要因子是西北太平洋平均海温、长治县的地温等因子,2001~2004年预报准确率达87.5%。     

梯级水坝胁迫下东江鱼类产卵场现状分析

东江作为珠江流域重要支流之一,是香港地区以及珠江三角洲东部地区重要水源.鱼类不仅是河流生态系统重要组成也是其健康状况的重要指示生物.目前东江已经修建了一系列水坝,基于东江河流生态系统健康维持和管理的需要,有必要了解河流中鱼类产卵场的现状.据此,2010年3-10月对东江古竹江段的鱼苗(卵)进行了连续采集,目前鱼苗种类已鉴定到26种(属),主要优势种类为鰕鯱(63.0%)、赤眼鳟(16.8%)、尼罗罗非鱼(9.7%)、大眼鳜(2.0%)等;调查期间古竹江段鱼苗(卵)径流量初步估算为11.4×108尾(颗),东江鱼类主要繁殖期为4-9月.与东江历史资料及西江江段鱼类繁殖现状相比较,东江鱼类产卵场功能极度退化,不仅鱼类产卵规模已明显下降,并且东江古竹江段鱼苗中洄游性种类缺失;本次调查证明东江龙川江段原有的四大家鱼产卵场已经消失;通过典范对应分析分析表明,东江江段鱼类产卵繁殖对水文生态因子的响应程度较低,说明东江江段水文节律受梯级水坝影响程度大,偏离了鱼类产卵繁殖的生态需求.尼罗罗非鱼在东江古竹江段有暴发性繁殖现象,东江已经面临外来种的严峻威胁,分析认为梯级水坝的修建是导致罗非鱼暴发性增长的主要原因之一.根据目前东江鱼类产卵场现状,建议把鲢、鳙及广东鲂列入增殖放流的品种目录,加强人工增殖放流;从贯通鱼类洄游通道及修复产卵场的需求上考虑,建议在东江各水坝上补建鱼类过鱼通道.     

净化湖泊饮用水源的物理-生态工程实验研究

我国许多历史上水质优良的湖泊水源区已污染严重污染,净化饮用水源刻不容缓。本文介绍了自１９９１年以来太源进行的物理－生态工程的部分研究成果。着重介绍在太湖的重富营养湖湾－五里湖无锡中桥自来水厂水源区的静态和抽水动态实验。     

EY60回声探测仪在青海湖鱼类资源量评估中的应用

2006年8月16-18日通过使用回声探测仪(Simrad公司EY60型,200kHz换能器)对青海湖的鱼类资源进行了探测评估.结果表明:青海湖裸鲤(Gymnocypris przewalski)水平分布具不均匀性,有小型鱼群聚集现象;在不同的设定分区,鱼类密度在0.168-12.8ind./1000m~3之间,均值为1.16 ind./1000m~3;布哈河口鱼类较为密集,密度最大值为12.8ind./1000m~3.初步估算青海湖裸鲤达可捕规格(体长大于20cm)个体数量为6.5×10~7ind.,95%置信度区间为35.6×10~7-118.4×10~7ind.,应用资源密度体积法估算青海湖裸鲤的可捕资源量约为1 5275t.探测实验还证实,EY60回声探测仪在青海湖中进行鱼类资源评估时探测效果良好,分析软件Sonar5可以对鱼类个体自动识别、计数,便于进行鱼类资源量评估.     

中国典型季风海洋性冰川区雪坑中主要阴、阳离子的来源研究

Snowpacks samples were colleted from two glaciers： Baishui No.1 glacier and Hailuogou No.1 glacier in June, 2006. The method of sea-salt ions tracer, correlation analysis and trend analysis were used in this research in order to confirm the source of main ions, it is indicated that Na^＋ is mainly from marine moisture and other ions mainly originate from land dust. The non-marine source percent of Cl^-, NO3^- , SO4^2-, K^＋, Ca^2＋ and Mg^2＋ is 52%, 99%, 100%, 98%, 99.9% and 83%, respectively, in Hailuogou No.1 glacier, while the corresponding value in Baishui No.1 glacier is 68%, 99%, 100%, 98%, 99% and 59%. The non-marine source of ions is from dust of Central Asia arid regions carried by westerly circulation and the plateau borne-areas with Qinghai-Tibet Plateau winter monsoon in two glacial areas. However, the import of local dust in glacial area has made a great contribution to ions concentration in Baishui No.1 glacier, which accounts for the reason why the ions concentration in Baishui No.1 glacier is much higher than that of Hailuogou No.1 glacier. It is obvious that the source of each ion is different between Hailuogou No.1 glacier and Baishui No.1 glacier. There are three reasons which can explain it： firstly, the difference in the internal environment of glacial area, such as lithology, mountain-valley wind system, topographical relief and so on; secondly, the influence exerted by ions elution in snowpacks section, and ions elution in Hailuogou No.1 glacier is very strong; and thirdly, the difference caused due to varying ions transporting styles, deposition modes, chemical characteristics and post-ions-deposition process.     

无网格伽辽金法(EFGM)在边坡开挖问题中的应用

无网格伽辽金法（ＥＦＧＭ）只需节点信息,不需将节点连成单元,具有精度高、后处理方便等优点。文中论述如何将该法用于边坡开挖问题,并给出相关算例。     

薄层地震响应分析及识别技术

对薄层地震响应的振幅,频谱等特征进行了详细的分析,并分析了影响该地震的应波形特征的因素。同时,利用积分能谱技术对其进行处理,可以识别出薄层的厚度变化及透镜体的存在。实际应用表明,该项技术较常规的时频分析方法有更高的分辨能力。     

糜棱岩型金矿床地质特征

当糜棱岩中金元素的含量足以满足工业利用,即在糜棱岩中可圈出独立的金矿体时,这种金矿床便可称为糜棱岩型金矿床.糜棱岩型金矿床是"中国金矿床工业类型"中的重要类型之一.此类金矿床多分布在古老地块周边长期活动的构造带之中.介绍了糜棱岩型金矿床的赋矿岩系、控矿构造、矿床、矿体、矿石以及含金矿物等地质特征.同时,对金成矿地质环境及矿床成因等作了探讨     

Transtensional tectonism and its effects on the distribution of sandbodies in the Paleogene Baiyun Sag, Pearl River Mouth Basin, China

The Baiyun Sag, situated at the north continental slope of the South China Sea, is a main sub-unit in the Southern Depression Belt of the Pearl River Mouth Basin. In this Sag, the middle Eocene Wenchang and upper Eocene–lower Oligocene Enping Formations had developed in the evolution stage of continental faulted basin. Seismic stratigraphic sequences and fault structures revealed that the Baiyun Sag was short of long-reaching boundary faults, and that it was a rifted basin greatly influenced by basement faults rather than a typical half-graben. Different from the sags in Northern Depression Belt of the Pearl River Mouth Basin which controlled by large-scale NEE-strike faults, the Baiyun Sag had been controlled by two groups of NWW-strike en echelon fault belts with approximate opposite dips, which developed in the southwest and northeast of this Sag respectively and had played the roles of boundary faults. These en echelon faults, together with narrow synclines, partial flower structures and fluid diapirs, indicated the left-lateral transtensional activities, which had resulted in subsidence center departing to main faults and stretching S-shaped. Moreover, the en echelon faults had constructed many composite transfer zones of relay ramps, and controlled the distribution of sandbodies. The en echelon fault belts are located in accordance with Nw-striking Mesozoic basement faults. Hence the left-lateral transtensional activities were responsible for the Western Pacific Plate subducting and strike slip reactivation of the basement faults. Significantly, NW-striking basement faults had forcefully determined the development of not only the Baiyun Sag but also the Xingning Sag.