APPARENT RESISTIVITY TEMPORAL VARIATION CHARAC-TERISTICS AFFECTED BY THE FIXED DISTURBANCE SOURCE ON SURFACE OF MEASURING AREA

Current leakage,metallic conductor,and local anomalous resistivity body are main disturbance sources which affect the successive observation of apparent resistivity in stations,besides the observing system failure.We construct a finite element model using a 3-layered horizontal medium to discuss the dynamic characteristics of disturbances caused by metal conductor and local anomalous resistivity body in the measuring filed.The numerical results show that low resistivity source which is located in areas where the sensitivity coefficient is positive will cause decline on apparent resistivity observation.While low resistivity source will cause increase when it is located in areas where the sensitivity coefficient is negative.Disturbance caused by high resistivity source is opposite to the one from low resistivity source.The general dynamic feature of disturbance is that the disturbance amplitude increases as the resistivity of shallow layer decreases,while the amplitude declines when the shallow layer's resistivity increases.For the measuring direction which has normal annual variation form,low resistivity source which is located in area where the sensitivity coefficient is positive will increase the annual variation amplitude,while it will reduce annual amplitude when it is in a negative sensitivity coefficient area.Annual amplitude changes caused by high resistivity source are opposite to the changes caused by low resistivity source.For the measuring direction which has abnormal annual variation form,dynamic annual feature is opposite to the one in direction of normal annual variation form.If the dynamic feature is opposite to the annual variation and disturbance amplitude is also greater than annual amplitude,the annual variation will change direction.Disturbance amplitude from metallic conductor is affected by the resistivity and cross-section area,the lower of the resistivity and the larger of the cross-section area,the greater of the disturbance amplitude.     

地质钻探技术与应用研究

钻探技术是取得地下实物资料、验证地下信息推断与解释、最终圈定矿体、计算储量、评估品位唯一的技术手段,是实现取得宏观影响大成果的重要技术支撑.我国钻探技术和装备水平与国外先进国家相比有很大的差距,但近些年来有了长足的发展.通过国家重大科学工程项目“中国大陆科学钻探工程”5158m“科钻一井”的实施,取得了一系列钻探技术成...     

西北太平洋海区年际至十年际海面变化尺度耦合与波动转型

利用多通道奇异谱分析(MSSA)等多尺度分析方法,对西北太平洋海区14个站位验潮序列的年际到十年际尺度海面波动的时空特征进行探讨.结果表明:2.5a周期和4.5a周期在振幅与相位上表现出与ENSO指数波动的尺度耦合,并存在显著的由低纬向高纬的振幅、能量递减的纬向传递特征.4.5a周期和8a周期与PDO变化同样表现出一定的尺度耦合波动,高纬各站位海面波动也表现出一定的自东向西的径向传递.在空间维上,PDO作用下的传播型波动的响应范围明显小于ENSO事件,反映了二者驱动机制的差异.该海区约在1973年和1998年左右发生过两次明显的海面波动转型,并与太平洋年代际涛动(PDO)存在一定关联.     

南海南部深水区低品质地震资料处理关键技术

中国南海南部深水区勘探前景广阔,但地震资料极其稀少且品质低。针对中国南海南部深水某区块原始地震资料采集于20世纪70年代、无导航文本、海底记录时间不确定、缺道严重及电缆短的品质限制,造成该区仅有的纸质成果剖面上多次波严重、信噪比低、地层构造形态模糊问题,探索出一套适合于工区地震资料处理的关键技术:采用导航重构技术解决无导航文本问题;采用自相关海底拾取技术解决海底记录不确定问题;采用限频F-K域插值技术解决缺道问题;采用组合法压制多次波技术解决因电缆短多次波难压制问题。最后处理效果表明关键技术的应用使该区地震资料处理取得了预期效果。这些技术成果不仅为我国南海南部深水的油气勘探提供较可靠的地震资料,同时为类似低品质地震资料的处理提供了可借鉴的思路和技术。     

南海西北部海区声速垂向及断面分布特征

根据南海西北部海区2012年2月实测的CTD资料计算出该海域的声速,给出了声速的垂向分布的几种类型和断面的分布状况以及它们的一些重要特征.并根据浅海声速跃层标准(ΔC/ΔH≥0.5/S),讨论了本海域声速跃层的分布状况.     

气候系统内极区热汇与热带海洋热源之间的相互作用(英)

The anomalous change of two polar sea ice and tropical ocean SST is a very important index for global climate monitoring and prediction. In this paper, the wave resonance principle is used to calculate month by month running cross couple correlation coefficient time series between sea ice in different sea area of two Polars, as well as between them and five elements of E1 Nino events, to analyze their variation features, and to find out their resonance periods. The resonance period of two waves is just the strongest interaction period.Some results are concluded as follows. 1) The Arctic sea ice to the Pacific-side (NPI1) and Atlantic-side (NP12) show a strong positive-negative feedback impact each other to the Antarctic Ross Sea ice (SPI2) with equal intensity. 2) Both NPI1 and NPI2 give a strong positive and negative feedback to the Antarctic Wedded Sea ice (SPI3) while it is rather weak in convercse status. It means that, the Arctic sea ice plays a leading and controlling role on the Wedded Sea ice. 3) SST of Nino 4 area in thecentral equatorial Pacific has a best resonance period with SPI2 with cycle period of 132 months. It closely relates to quasi-11 years oscillation period of both SST of Nino 4 area and SPI2. SST of Nino 4 has also a resonance period to SPI3 with cycle of 61 months. There also exist strong interaction periods between the Antarctic sea ice and other elements of ENSO event but weaker than SST of Nino 4 area.     

红河断裂带两侧地块地震震源参数研究

利用云南区域数字地震遥测台网资料,采用Brune圆位错模型对1998年12月至2006年8月云南境内M≥3地震和越南北部M>2地震测算震源参数。结果表明,红河断裂两侧活动块体的地震活动和震源参数存在较为明显的差异。就地震矩与震级的标度关系而言,滇西南块体与美国加州圣安德列斯断层和滇西实验场及其周边地区的结果一致,但与华南块体和越南北部地区有差异;从应力降的测算结果看,华南块体西缘的云南及越南北部地区的年均值为7.29MPa,滇西南块体为4.48MPa,两块体北部地震的应力降大于南部地区,应力降由北向南逐渐减小;就地震位错年均值而言,华南块体为12.3mm/a,滇西南块体为6.6mm/a。     

中国冰川径流的评估及其未来50 a变化趋势预测

基于中国冰川编目资料,应用冰川系统对气候变化响应的功能模型,按照几种不同升温率的气候背景,对全国各大流域冰川径流进行了评估,并对未来50 a冰川径流的变化趋势进行了预测.结果表明:1980年全国冰川总径流量615.7×108m3,在升温0.02 K.a-1及0.03 K.a-1情景下,2000年比1980年增大7.13%~10.8%,径流总量增至659.66×108m3~682.24×108m3;与此同时,冰川面积减少1.07%~1.62%,冰储量也减少1.14%~1.73%.2000—2030年全国冰川径流都将逐步增长,在2030年左右均达到了最高峰,径流增率ΔW/W0分别为9.6%及15.0%,总径流量分别为675.15×108m3,和707.91×108m3.2030年以后,全国冰川径流均开始从高峰缓慢回落,但直到2050年分别比初始径流量多8.6%及13.6%.因此,在2050年以前,特别是2030年前后是在上述气候情景下充分利用冰川融水的最好时机,但也是冰川洪水等灾害的多发期.就各流域来说,敏感型区径流高峰出现时间早而径流增率小,稳定型区则反之.如果出现极端的持续升温,如升温率为0.05 K.a-1,全国冰川径流增率可达26.5%,到21世纪末回落到1980年水平以下,而冰川储量损失达57%,届时中国西部生态环境将急剧恶化.