四种海水透明度现场测量方法的对比分析及发展趋势研究

随着海洋探测的不断发展,海水透明度作为海水光学性质的一个重要参量,也越来越受到人们的关注。文章对比分析了4种海水透明度现场测量方法:透明度盘法~([1])、光纤式高光谱剖面测量法~([2])、激光衰减测量法~([3])和基于双光路原理的海水IOPs高光谱测量法~([4]),主要分析了4种方法的测量原理,对比各自的优缺点,并提出了海水透明度测量未来发展设想。     

巴黎气候会议对全球长期目标的新发展

巴黎气候会议（COP21）达成了包括《巴黎协定》在内的重要成果,丰富和深化了应对气候变化的一揽子长期目标。1.5℃温升控制目标意味着全球管控气候风险的政治意愿得到强化,减缓温室气体排放的路径得到初步勾勒。在未来的科学评估和政治谈判中,全球各区域甚至是各个排放大国的排放空间、排放路径和减缓需求将会进一步清晰化和定量化,还会丰富和深化自上而下的国际气候合作规则,结合当前以国家自主决定贡献（INDC）为特征的、主要以自下而上方式推进全球气候治理的新模式,将对发展中国家、尤其是发展中排放大国的排放配额与发展空间产生重要影响,并进一步影响各国制定其国家贡献目标与行动的自主性。     

滇西牟定—香格里拉电性剖面及深部构造

通过对滇西NW—SE向牟定—香格里拉大地电磁测深剖面的反演并结合地质构造、小震精定位资料,综合分析了剖面经过地区的深部构造.在滇西北地区深部发育一规模巨大的近水平产出地壳高导层,此高导层从香格里拉一直延伸到永胜盆地以东,沿剖面水平延伸超过200km.地壳高导层又可分为两段,两段高导层在剖面上形成两个香蕉型相连的复合形态,高导层之上的高阻体则形成两个碗型相连的复合结构,碗型内部有向东倾斜的相对低阻带存在.滇西北地区整体构造格架可以解译为一套两个主推覆面构成的叠瓦式推覆系统,两个主推覆面高低起伏形成总长度超过250km的底部滑脱带.第一个主推覆面的长度超过150km,并在丽江东部上翘到接近地表,小金河断裂是其延伸到地表的主要破裂带.第二个主推覆面长度超过120km,过程海断裂后上翘并在永胜以东地区出露地表.根据反向低阻带影像,可以推断推覆体反冲构造发育,在玉龙山至丽江以东和永胜盆地西缘至平川盆地东缘形成两处冲起构造.推覆面在剖面上呈现出平缓-陡峭-再平缓-再陡峭的断坪和断坡相间的阶梯状结构.     

The numerical and empirical evaluation of chimneys considering soil structure interaction and high-temperature effects

During the past strong ground motions, chimneys constructed according to international standards are representative of similar structures at industrial areas throughout the world, including those collapsed or moderately damaged in earthquake-prone regions. This is due to the specialty of structural characteristics and the special loads acting on the structure such as earthquakes, wind and differences in the level of temperature, etc. In this context, the researchers and designers should focus on the dynamic behavior of chimneys especially under high temperature and seismic effects. For this purpose, the main focus of this study is to evaluate the dynamic response of a chimney under the above-mentioned effects considering soil-structure interaction (SSI). A 52 m steel chimney in Yeşilyurt township of Samsun City in Turkey was studied. The in-situ model testing and numerical models were compared. Before the commissioning of the chimney, a series of tests was realized to define its dynamic characteristics in case of no-heat and after the fabric got to work, the same tests were repeated for the same sensor locations to understand the heat effect on the dynamic response of the chimney. The ambient vibration tests are proven to be fast and practical procedures to identify the dynamic characteristics of those structures. The dynamic testing of the towers promises a widespread use, as the identification of seismic vulnerability of such structures becomes increasingly important. The data presented in this study are considered to be useful for the researchers and engineers, for whom the temperature and SSI effects on steel chimneys are a concern. Using the modal analysis techniques, presented finite element simulation for the soil/pile foundation-chimney interaction system is verified. The results of modal analyses using numerical solutions are shown to have acceptable accuracy compared with results obtained by in-situ test. The present study also aims to provide designers with material examples about the influence of these on the seismic performance of steel chimneys by means of reflecting the changes in the dynamic behavior.     

新疆东准噶尔花岗岩类岩石高温高压弹性波速度及其对地壳结构的约束

应用超声波反射-透射法,在最高压力为1.0 GPa（室温）,最高温度为700℃（1.0 GPa）的条件下对新疆东准噶尔地区的卡拉麦里花岗岩带和野马泉岩体的典型花岗岩类岩石（碱长花岗岩、碱性花岗岩、花岗闪长岩、二长花岗岩和石英闪长岩）的纵波速度（V_P）和横波速度（V_S）进行了测量.结果显示,在常温、压力0.4~1.0 GPa条件下,东准噶尔地区花岗岩类岩石的V_P和V_S均随压力呈线性增加,说明在这个压力段岩石中的微裂隙已基本闭合.室温、1.0 GPa时花岗岩类岩石的V_P是5.79~6.84 km·s^-1,V_S是3.26~3.85 km·s^-1.依据压力与V_P及压力与V_S的线性关系,拟合得到常温常压下花岗岩类岩石的纵波和横波压力系数分别是0.1568~0.4078 km/（s·GPa）和0.0722~0.3271 km/（s·GPa）,V_P0和V_S0分别是5.62~6.47 km·s^-1和3.15~3.75 km·s^-1.恒压1.0 GPa、室温到700℃条件下,花岗岩类岩石的V_P和V_S均随温度的升高呈线性降低,温度系数分别为（-3.41~-4.96）×10^-4 km/（s·℃）和（-0.88~-3.22）×10^-4 km/（s·℃）.利用实验获得的花岗岩类岩石的V_P0、V_S0及温度系数和压力系数,结合东准噶尔地区的地热资料,建立了V_P和V_S随深度变化的剖面.将获得的V_P和V_S-深度剖面与该区地球物理探测结果对比,发现东准噶尔地区的碱长花岗岩、碱性花岗岩、二长花岗岩和部分花岗闪长岩的V_P和V_S与该区上地壳速度吻合很好,同时这几种岩石的平均泊松比也与上地壳泊松比一致,因此我们认为这几种类型的岩石是该区上地壳的重要组成部分.另外,石英闪长岩的V_P和V_S均符合中地壳的速度,可能为中地壳中的一种岩石.     

The effects of asymmetric potential vorticity forcing on the instability of South Asia High and Indian summer monsoon onset

Based on the theory of potential vorticity(PV),the unstable development of the South Asia High(SAH)due to diabatic heating and its impacts on the Indian Summer Monsoon(ISM)onset are studied via a case diagnosis of 1998.The Indian Summer Monsoon onset in 1998 is related to the rapidly strengthening and northward moving of a tropical cyclone originally located in the south of Arabian Sea.It is demonstrated that the rapid enhancement of the cyclone is a consequence of a baroclinic development characterized by the phase-lock of high PV systems in the upper and lower troposphere.Both the intensification of the SAH and the development of the zonal asymmetric PV forcing are forced by the rapidly increasing latent heat released from the heavy rainfall in East Asia and South East Asia after the onsets of the Bay of Bengal(BOB)monsoon and the South China Sea(SCS)monsoon.High PV moves southwards along the intensified northerlies on the eastern side of the SAH and travels westwards on its south side,which can reach its northwest.Such a series of high PV eddies are transported to the west of the SAH continuously,which is the main source of PV anomalies in the upper troposphere over the Arabian Sea from late spring to early summer.A cyclonic curvature on the southwest of the SAH associated with increasing divergence,which forms a strong upper tropospheric pumping,is generated by the anomalous positive PV over the Arabian Sea on 355 K.The cyclone in the lower troposphere moves northwards from low latitudes of the Arabian Sea,and the upper-layer high PV extends downwards and southwards.Baroclinic development thus occurs and the tropical low-pressure system develops into an explosive vortex of the ISM,which leads to the onset of the ISM.In addition,evolution of subtropical anticyclone over the Arabian Peninsula is another important factor contributing to the onset of the ISM.Before the onset,the surface sensible heating on the Arabian Peninsula is very strong.Consequently the subtropical anticyclone which dominated the Arabian Sea in spring retreats westwards to the Arabian Peninsula and intensifies rapidly.The zonal asymmetric PV forcing develops gradually with high PV eddies moving southwards along northerlies on the eastern side of the anticyclone,and a high PV trough is formed in the middle troposphere over the Arabian Sea,which is favorable to the explosive barotropic development of the tropical cyclone into the vortex.Results from this study demonstrate that the ISM onset,which is different from the BOB and the SCS monsoon onset,is a special dynamical as well as thermodynamic process occurring under the condition of fully coupling of the upper,middle,and lower tropospheric circulations.     

中国西北地区旱涝年南亚高压异常特征

利用1961年1月1日至2010年12月31日NCEP/NCAR再分析数据和站点观测资料,统计分析表明：中国西北区域重旱年典型特征为3、4月南亚高压中心均出现偏西约40°;偏旱年典型特征为3月至4月出现中心位置西移之后东撤,4月至5月出现西移,或4月偏东40°;偏涝年典型特征为7月至8月东西振荡幅度大;西北区域多雨年典型特征为5月中心位置位于孟加拉湾海域,9月明显出现南亚高压东部型,12月位置偏西40°。面积距平最明显的特征是重旱年、偏旱年南亚高压面积偏小,偏涝年、多雨年南亚高压面积偏大,同样也可以看到重旱年4月南亚高亚异常特征十分明显。强度和面积与西北区域降水很好的相关性主要存在于2—4月。     

从页岩气革命看中国资源勘探的战略方向

美国页岩油气开发的巨大成功不仅对美国乃至世界油气供应格局产生明显影响,而且对地下资源勘探开发思路有重大启示.首先,向低品位资源开发能使可用资源的数量成倍增加;其次,找油找矿思路的拓宽可导致新区新领域的开拓;第三,实现上两点必须有技术水平创新式发展.中国矿产资源发展的战略方向亦应强调向多种低品位资源的开拓,提高选矿水平,推进资源的综合勘探开发利用.为此,要积极持续地进行找矿新思路、新领域和新技术研究.     

基于参考线圈和变步长自适应的磁共振信号噪声压制方法

核磁共振地下水探测仪的灵敏度高,接收到的纳伏级磁共振探测信号极易受到强工频谐波噪声的干扰,导致信号特征参数提取的准确度降低,影响反演解释的水文地质参数结果.为了解决这一难题,基于相关抵消的原理,针对全波磁共振信号,设计带有参考线圈的90°移相自适应噪声抵消系统,理论计算了参考线圈相对于探测线圈的距离,提出变步长LMS算法进行噪声压制.仿真结果表明,在不同的信号强度及不同的信噪比下,当信号与工频谐波干扰频谱不重合时,采用设计的自适应噪声抵消系统和变步长算法,信噪比可以提高到5.94 dB以上,初始振幅、弛豫时间特征参数的拟合误差在2.8%以内;当信号与工频谐波干扰频谱重合时,采用双向自适应滤波算法,信噪比可以达到5dB以上,初始振幅、弛豫时间特征参数的拟合误差在10%以内,可以满足实际应用的要求;实测数据处理进一步证明了方法的有效性.     

地震散射波的高精度数值模拟与振幅分析

随着地震勘探要求和技术的不断提高,散射波地震勘探方法逐渐引起人们的重视,尤其在构造复杂地区的高精度勘探中,散射波理论具有广泛的应用前景.本文在讨论了现阶段几种散射波数值模拟方法的利弊后,设计了一种基于微扰论的FK域积分法,在散射场的二次震源和空间能量衰减处理两方面做了改进,其计算精度和效率均得到了提高.此外,采用该算法针对散射波动力学进行了正演模拟试算,从扰动介质空间分布和扰动量两个角度定量地分析了散射波振幅动力学方面的特征.在此基础上得到了五个经验常数,并给出了对应的计算公式和物理意义,通过这五个常数可以划分散射波不同形态的动力学特征.