探地雷达探测地下管线技术与应用实例

根据探地雷达的探测原理及技术参数影响因素，提出了工作频率的选择方法。以广州和商丘两地的两个探测实例，介绍了如何根据管径、埋深确定天线频率、天线距、采样点距、时窗等探地雷达技术参数；并选择已知埋深的管线，对波速进行实地测定，以便在探地雷达剖面上对目标体的埋深作出精确解释。     

NCAR RegCM2对1991年夏季江淮流域异常降水事件中关键物理过程的模拟能力检验

选取1991年夏季江淮流域发生的持续性特大暴雨洪涝个例,利用NCAR第二代区域气候模式RegCM2对逐日降水过程及其关键物理因子进行了数值模拟.模式的侧边界条件由ECMWF的大尺度分析资料提供,模拟时间为1991年5-8月.模式范围包括东亚地区及相邻海域,水平分辨率为60 km×60 km,垂直方向为23层.试验结果显示,该模式能够合理地模拟出1991年夏季东亚地区的逐日降水过程,特别是在江淮流域发生的异常降水事件.对一些关键物理变量和过程时空结构的分析表明,大气垂直速度和水平散度的时间演变与江淮流域的5次降水事件一致;形成异常降水的水汽来源主要是大气的水平运动输送。西太平洋副热带高压控制着东亚夏季季风的进退,RegCM2能够模拟出西太平洋副高的南北位置移动。而且,模式能够较好地再现出对水汽输送至关重要的低空急流的逐日变化。     

中美大气化学联合考察实验结果的初步分析与比较

根据临安区域本底站观测资料分析结果得出,中国中纬度地区秋、冬季O₃及其前体物NO_x等浓度偏高,可以对农作物和地表生态系统产生影响.观测结果表明:近地层大气O₃浓度主要决定于地面总辐射量控制下的光化学反应过程;O₃的生成受到前体物NO_x的控制,但O₃与NO_x存在着明显的非线性关系.从PEM-WESTA和B的实验及1995年的观测资料表明,O₃的生成效率随着NO_x浓度的增大而减小.尽管O₃的生成速率秋季比冬季的大,但由于秋季较高的NO_x抑制了过氧基的生成,因此冬季O₃的累积量几乎可以和秋季相比拟.在临安观测的NMHC和NO_x的比值比国外同纬度地区测值要大.这说明在临安本底站O₃的光化学生成中,NMHC不是控制物种.从而提示我们,在这些季节临安O₃光化学产物能够被NO_x浓度所控制.中美大气化学联合考察(PEM-WEST-B)实验期间,台湾省的卡盯站SO₂的平均浓度为0.29ppb,O₃的平均浓度为42.2ppb,可以认为此值为低纬度海岛的本底值.1994年PEM-WEST-B实验期间临安站的观测资料和台湾省的卡盯站资料相比,临安站SO₂的浓度约为卡盯站SO₂浓度的50倍左右,从而可以看出人类活动对大气本底的显着影响.     

Theoretical relationship between SSA and MESA with both application

Ｉ．ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｇｕｌａｒｓｐｅｃｔｒａｌａｎａｌｙｓｉｓ（ＳＳＡ）,ａｓａｎｅｗｄｉａｇｎｏｓｔｉｃｍｅｔｈｏｄ,ｈａｓｂｅｎｅｘｔｅｎｓｉｖｅｌｙａｐｐｌｉｅｄｉｎｃｌｉｍａｔｉｃｄｉａｇｎｏｓｅｓａｎｄｐｒｅｄｉｃｔｉｏｎｗｉ...     

爆发性气旋的统计研究

用１９８０～１９８９年资料,统计了发生在北半球的爆发性气旋的若干特征,并通过不同区域,不同时间及强度的爆发性气旋发生的频率的对比,得到了一些有意义的结果。     

γ射线康普顿背散射扫描仪测量的信噪比研究

本文详细给出了ＣＢＳ测量中噪声的物理来源和降低噪声的有效措施,还对信噪比进行了定量的分析和讨论。     

A preliminary research establishing the present-time intraplate blocks movement model on the Chinese mainland based on GPS data

The Chinese mainland is regarded as the best area for studying the continental crustal movement and dynamics. In the past, based on the ground surface observation, it was very difficult to study the movement of the intraplate blocks within a range of larger space and a time scale of several years quantitatively. In this paper, a method of calculating the Euler vectors of present-time motion among blocks by using Cardan angles has been given completely based on two periods of GPS repetition measurement data of the National Ascending Plan of China (NAPC) — the study and application of current crustal movement and geodynamics in 1994 and 1996. A present-time blocks movement model on the Chinese mainland (PBMC-1), which describes the motion of seven blocks—Tibet, Chuan-Dian, Gan-Qing, Xinjiang, South China, North China and Heilongjiang block, is established preliminarily. The velocity field of the relative motion among the intraplate blocks and boundary motion in the Chinese mainland are firstly given within several years time scale. It is shown by the results calculated with the model that the velocity-rate of each block is reduced gradually from the south to north and from the west to east, and the motion direction changes gradually from NNE to E, even SEE or SE. The collision of Indian plate plays a leading role in the movement of the intraplate blocks in the Chinese mainland, while the motion manner and velocity-rate of block boundary zone (fracture zone) depend on the motion of every block again. The present-time motion of a time scale of several years computed with the model is not only largely consistent with the average motion of a time scale of several million years derived from geology, but also very coincident with the results of geophysical and astronomic observation. It is shown preliminarily that the observed results of space geodesy techniques such as GPS etc. are capable of discovering the crustal movement at present. This study is supported by the National Natural Science Foundation of China (NNSFC), National Ascending Plan of China (NAPC) and Chinese Joint Seismological Science Foundation (CJSSF).     

青藏高原东北隅似三联点构造特征

在大陆内部,对于一定尺度的构造块体,似三联点构造是一种普通的构造形式。由于大陆内部块体旋转的普遍性,似三联点构造可形成顺旋型和逆旋型两种构造型式。     

New paleomagnetic results from Ceno-Mesozoic volcanic rocks along southern rim of the Tarim Basin,China*

Paleomagnetic samples were collected from four localities located in the southern rim of the Tarim basin. The samples were taken from volcanic rocks erupted between Jurassic and Quaternary. Detailed analysis of all samples has been carried out with progressive thermal demagnetization. A characteristic remanence (ChRM) with higher unblocking temperature has been isolated from all samples. The pole position from the middle Jurassic is at 52.5°N, 187.9°E(dp = 3.7°,dm =6.5°); the directions of the ChRM of Cretaceous correspond to a paleopole at 69.7°N, 211.6°E (dp = 9.8°,dm = 15.9°); the Quaternary pole from the Pulu site is at 79. 9°N, 183.1°E(dp = 1.6°.dm =2.4°). On the basis of these new paleomagnetic data, tectonic evolution of Tarim block is presented.

     

胶东望儿山金矿带有限应变分析及其意义

望儿山金矿带中广泛发育变形石英颗粒。经三维有限应变分析表明,望儿山断裂曾经历过强烈的挤压作用,金矿体定位于断裂带的扩容空间,矿体附近付林参数普遍表现为拉伸型。构造岩有限应变椭球体拉伸轴,主要集中于ＮＥ—ＳＷ向,含矿热液在区域应力及岩浆热动力作用下,沿望儿山断裂带运移。成矿过程中,体系是开放的。