Morphological response of tidal marshes,flats and channels of the Outer Yangtze River mouth to a major storm

Systematic morphological changes of the coastline of the outer Yangtze River mouth in response to storms versus calm weather were documented by daily surveys of tidal marshes and flats between April 1999 and May 2001 and by boat surveys offshore during this and earlier periods. The largest single event during 1999 to 2001 was Typhoon Paibaian, which eroded the unvegetated tidal flat and lower marsh and led to accretion on the middle-to-upper marsh and in the subtidal channel. The greatest erosion of 21 cm occurred at the border between the marsh and the unvegetated flat due to the landward retreat of the marsh edge during the storm. Strong waves on the flats increased suspended sediment concentration by 10–20 times. On the upper marsh, where the frequency of submergence by astronomical tides is only 3%, Typhoon Paibian led to 4 cm of accretion, accounting for 57% of the net accretion observed over the 2-yr study. Typhoon Paibian led to 4 cm of accretion, accounting for 57% of the net accretion observed over the 2-yr study. Typhoon Paibian and other large storms in the 1990s caused over 50 cm of accretion along the deep axis of the river mouth outlet channel. During calm weather, when hydrodynamic energy was dominated by tides, deposition was centered on the unvegetated flats and lower, marsh with little deposition on the high marsh and erosion in the subtidal channel. Depositional recovery of the tidal flat from typhoon-induced erosion took only several days, whereas recovery of the subtidal channel by erosion took several weeks. A conceptual model for the morphological responses of tidal marshes, flats, and subtidal channels to storms and calm weather is proposed such that sediment continually moves from regions of highest near-bed energy towards areas of lower energy.     

海南JX地区高精度重磁资料综合地球物理解释

根据高精度重磁资料，经过计算机各种方法处理及综合分析，可以查明盆地内大的断裂、火成岩及局部的构造展布。同时指出，长流断裂的下降盘是油气勘探有意义的地区。     

贵州省近30a秋风的气候特征分析

利用1981—2010年30 a贵州省78站逐日日平均气温数据和NCEP/NCAR逐日的再分析资料,采用合成、EOF分解、傅立叶滤波等方法,分析了贵州省秋风的气候特征。结果表明:贵州省秋风天气强度有自西向东部或向东南部、东北部递减的分布规律。贵州省异常秋风过程次数的空间分布表现为全省各站呈同位相变化,进入2000年后,秋风过程次数由全省秋风偏弱偏少型转为全省秋风偏多偏强型。在环流场上,纬向西风在不断东移的过程中不断分裂出短波槽引导冷空气南下影响贵州,形成秋风天气过程,因而造成的秋风过程时间较长,强度较大。对秋风过程的环流场进行滤波表明:1波对于秋风过程有着十分显著的影响,而1波、2波在时间上的配合对于秋风过程也非常重要。     

Feasibility of central loop TEM method for prospecting multilayer water-filled goaf

With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic (TEM) method is favorable for prospecting conductive layers because of the coupling relationship between its field structure and formation. However, the shielding effect of conductive overburden would not only require a longer observation time when prospecting the same depth but also weaken the anomalous response of underlying layers. Through direct time domain numerical simulation and horizontal layered earth forward modeling, this paper estimates the length of observation time required to prospect the target, and the distinguishable criterion of multilayer water-filled goaf is presented with observation error according to the effect of noise on observation data. The observed emf curves from Dazigou Coal Mine, Shanxi Province can distinguish multilayer water-filled goaf. In quantitative inversion interpretation of observed curves, using electric logging data as initial parameters restrains the equivalence caused by coal formation thin layers. The deduced three-layer and two-layer water-filled goafs are confirmed by the drilling hole. The result suggests that when observation time is long enough and with the anomalous situation of underlying layers being greater than the observation error, the use of the central loop TEM method to prospect a multilayer water-filled goaf is feasible.     

北斗静态定位实验与精度分析

通过实际测试,将北斗和GPS进行对比,了解北斗静态定位的实际定位精度情况。按照E级网测试的结果表明,北斗和GPS定位的平面点位平均中误差分别为2．51mm和0．75mm,证明北斗系统和GPS的平面定位精度基本在同一量级上,能够满足静态定位测量的需要。     

江宁台多孔垂向地电阻率观测试验

为了提高地电阻率观测抑制地铁干扰的能力,江宁台新建了多孔垂向地电阻率观测。在观测中探讨完善了装置系数计算方法,解决了缺数问题,并通过比较同测区井下和垂向地电阻率观测数据,得出如下结论:(1)垂向观测由于布极方式较为特殊,其年变化幅度大于井下地电阻率观测同等极距;(2)与井下地电阻率观测相比,垂向地电阻率观测信噪比更高,具备更好的抗地铁干扰能力,以期为地电观测抗干扰的方法和技术应用提供基础;(3)垂向地电阻率观测建设中,可能需要重视电极的位置固定。     

黄河下游游荡段河道平面形态与河热变化趋势预测

黄河下游可道平面形态与河势演变,从２０世纪６０年代起,地貌界就用地图法和航片资料作过不同程度的研究。随着资料的不断积累,该项研究得到逐步的深化。“八五”期间,水利界又对主流线作了深入分析,结果表明：各家所得结论不同,需要作进一步的分析讨论。我们认为：从长远的角度来看,小浪底水库清水下泄期间,黄河下游游荡性可段不对称的河谷形态不会改变;在继承性新构造运动造成的地壳向南掀沉、科氏力和人类活动的综合影响     

Retrogressive Microstructures:A Key to Post Collisional Uplift and Extension Tectonics of Ultrahigh-Pressure Metamorphic Rocks from Dabie Orogenic Belt,China

ThereisanunanimousunderstandingthattheUHPmetamorphisminDabie-SuluareaswasformedduringtheTri-assiccollisioneventbetweentheYangtzeandNorthChinacratons(Congetal.,l994$Zhouetal-,l996;Liouetal.,l994)-Eclogiteisthemostimportantrocktypeamongtheul-trahigh-pressure(UHP)metamorphicrocks.Accordingtotheiroccurrencethereare3typesofeclogites:typeIisen-clavesinultramaficintrusionsandasmembersinthelayeredmafic-ultramaficcomplex(Jahnl998);typeIispodsorlay-ersinthehighlymetamorphicsupracrustals(mainlying…     

Advances in the Research of Impact of Decadal Solar Cycle on Modern Climate

Role of solar activity on modern climate change, particularly in the decadal scale is an important scientific issue. This paper reviews the recent observation of decadal solar signal in earth’s climate, with focus on the mechanism of solar radiation, ultraviolet radiation and cosmic rays on climate system ,and its validation. The paper points out that the assessment of uncertainty in observations, amplification process of the climate system, as well as possible future impact of solar extreme events are challenges in the present study. Finally, the keys of breakthrough are pointed, to provide a reference for future research.     

最小静校正量基准面校正技术在准噶尔盆地LN6井区应用

最小静校正量基准面技术在原理上优于水平基准面一步法校正,实际应用有多大的优势?以准噶尔盆地LN6井区为例,从基本原理、静校正量计算、速度建场,对最小静校正量基准面校正和水平基准面一步法校正进行对比。在构造圈闭目标识别过程中,使用最小静校正量基准面校正技术,构造精度上取得好的成果,提供部署预探井位一口。