松辽盆地宋芳屯油田扶杨油层孔隙结构及其影响因素

通过镜下观察,宋芳屯油田扶杨油层孔隙类型较多,以粒间孔为主。细管压力曲线上看,曲线较陡,分选差,孔隙结构特征参数总体上较差,与孔隙度、渗透率有一定的关系,大的孔隙对渗透率的贡献最大。扶杨油层的孔隙结构较复杂主要由于成岩作用影响,压实作用使孔隙空间显著缩小,胶结作用和自生粘土矿物生长使孔隙进一步缩小和复杂化,后期的溶蚀作用使孔隙空间增加。     

CORS系统下GPS-RTK在山区地形测绘中的应用

GPS-RTK技术是测绘行业的一次历史性革命,它以高效精准的定位方式应用于测绘行业的各个领域。本文以北京市昌平区鹞子峪山区测绘1∶500数字地形图为例,对在CORS系统下GPS-RTK在数字化测绘中的应用进行相关介绍。     

岭参数确定的研究

中文阐述了多种岭参数确定方法的原理,如岭迹法、L曲线法、两步解法、GCV法和双h公式法,应用数据编程比较了各种岭参数计算方法所得的结果及对最小二乘估计的改进效果.结果表明,L-曲线法易于确定岭参数,是一种确定岭参数的良好方法.此外,两步解作为另一种解算病态问题的方法,不仅要明显优于LS估计,并且改善了L-曲线法的计算结...     

大气重力波触发的Rayleigh－Taylor不稳定性的时空演变

对大气重力波触发的赤道电离层Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性的时空演变进行了数值模拟．结果表明,重力波能在Ｆ区底部触发Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性,这种等离子体不稳定扰动穿过Ｆ峰,到达Ｆ区顶部,形成等离子体泡结构．等离子体泡出现向西倾斜和分岔等特征．当夜Ｆ区较高时,产生等离子体泡的时间仅１９００ｓ．数值模拟结果证实了重力波触发．Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性的理论,解释了大量电离层观测现象．     

Characterization of diurnal cycles in ZTD from a decade of global GPS observations

The diurnal cycle of the tropospheric zenith total delay (ZTD) is one of the most obvious signals for the various physical processes relating to climate change on a short time scale. However, the observation of such ZTD oscillations on a global scale with traditional techniques (e.g. radiosondes) is restricted due to limitations in spatial and temporal resolution. Nowadays, the International GNSS Service (IGS) provides an important data source for investigating the diurnal and semidiurnal cycles of ZTD and related climatic signals. In this paper, 10 years of ZTD data from 1997 to 2007 with a 2-hour temporal resolution are derived from global positioning system (GPS) observations taken at 151 globally distributed IGS reference stations. These time series are used to investigate diurnal and semidiurnal oscillations. Significant diurnal and semidiurnal oscillations of ZTD are found for all GPS stations used in this study. The diurnal cycles (24 hours period) have amplitudes between 0.2 and 10.9 mm with an uncertainty of about 0.5 mm and the semidiurnal cycles (12 h period) have amplitudes between 0.1 and 4.3 mm with an uncertainty of about 0.2 mm. The larger amplitudes of the diurnal and semidiurnal ZTD cycles are observed in the low-latitude equatorial areas. The peak times of the diurnal cycles spread over the whole day, while the peak value of the semidiurnal cycles occurs typically about local noon. These GPS-derived diurnal and semidiurnal ZTD signals are similar with the surface pressure tides derived from surface synoptic pressure observations, indicating that atmospheric tides are the main driver of the diurnal and semidiurnal ZTD variations.     

On the size distribution of ice-supersaturated regions in the upper troposphere and lowermost stratosphere

In order to determine typical sizes of ice-supersaturated regions (ISSRs) in the upper troposphere and lowermost stratosphere we set up the frequency distribution of path lengths flown by MOZAIC aircraft within ISSRs. The mean path length is about 150 km with a standard deviation of 250 km. We analyse the influence of a selection bias (viz. that large ISSRs are more often crossed by aircraft than small ones) on the obtained path length statistics and derive a mathematical equation that relates the path length distribution to the underlying size distribution of ISSRs, assuming that they have circular shape. We solve the equation (by trial and error) and test the result using numerical simulations. Surprisingly, we find that there may be many more very small ISSRs than apparent from the data such that the true mean diameter of the ISSRs may be of the order a few kilometres only. The relevance of the result is discussed and dedicated research flights to measure the true extension of ISSRs are recommended.     

江苏潮滩沉积物激光粒度仪与移液管-筛析分析结果的对比

激光粒度仪的广泛应用带来了与历史数据的对比问题,因此需要建立激光粒度仪与早期分析结果之间的关系。根据江苏海岸潮滩沉积物样品的激光粒度仪和移液管-筛析法分析,对粒度参数、粒度组分等进行了对比,对两种方法的差异进行了分析。结果表明,对于江苏潮滩沉积物粒度参数中平均粒径的激光粒度仪与移液管-筛析分析结果之间有良好的线性关系;筛分法测得的粗颗粒物质较激光法偏少,而移液管法法测得的细颗粒物质较激光法偏多;将样品分类之后再进行两种方法所获粒度参数的回归分析,相关性得以提高,说明不同粒度组成的沉积物对分析结果的对比有不同的影响。两种方法之间的换算关系不仅与研究区域有关,而且与沉积物本身的粒度组成有关。     

Equations of kinetic and available potential energy evolution in wave-number frequency space

The equations of kinetic and available potential energy for the analysis of the growth and decay of atmospheric waves in wave-number-frequency space are derived. The effects of linear and nonlinear interactions of waves in the velocity and temperature fields, the conversions between the available potential and kinetic energies, and the Reynolds and molecular stresses on wave growth and decay are discussed.     

南疆盆地沙尘气溶胶光学特性及我国沙尘天气强度划分标准的研究

依据气溶胶光学厚度测量原理,利用布设于塔里木盆地腹地塔中和盆地西南边缘和田气象站的2部CE318自动跟踪太阳光度计于2002年6月至2003年11月期间的探测结果,结合地面气象实测资料,分析了南疆盆地大气气溶胶的光学特性。同时结合我国已有的沙尘气溶胶光学特性的研究成果,初步提出了依据气溶胶光学厚度判断沙尘天气强度的标准。结果表明:塔中、和田气溶胶光学厚度随波长的增大多呈现减小趋势,塔中个别季节有些例外;2站气溶胶光学厚度的日变化基本保持对称的抛物线形,在春、夏季尤为明显;Angstrom浑浊度系数β的拟合曲线显示β随能见度增大而减小,波长指数α随能见度的变化趋势说明弱沙尘天气下,大气中主要弥漫着小粒径的气溶胶颗粒,而强沙尘天气则以大粒径为主;沙尘气溶胶光学厚度随晴空、浮尘、扬沙、沙尘暴依次增加;沙尘天气发生时,气溶胶光学厚度的临界值基本为晴空值的两倍,沙漠地区气溶胶光学厚度≥1.1206,北京≥0.3174。而发生沙尘暴的阈值则有很大不同,沙漠区气溶胶光学厚度至少 > 3.0,北京由于大气污染等因素,其判断沙尘暴发生的阈值为1.9982。另外笔者认为AOD与水平能见度之比值能够较全面地考虑水平和垂直两个方向的要素变化,衡量沙尘天气强度更具有合理意义,值得更深一步的探讨。     

落锤震源不同参数激发的数值模拟研究

本文通过研究落锤震源的物理模型,利用有限元方法,对震源激发到子波形成的全过程进行数值模拟研究。从激发参数角度,分别对软地表（土壤）和硬地表（岩石）条件下的不同落锤震源参数的激发进行数值模拟,分析不同震源参数对子波能量和频谱的影响,并比较不同地表岩性介质对震源参数变化的响应。同时将模拟结果同已有的数据采集研究和实验研究进行对比,以说明其有效性。研究结果显示落锤震源的激发效果同重锤质量、冲击速度、基板大小和基板材料的关系,为浅地表地震勘查中落锤震源参数的选择提供了参考依据。