Resurrecting vintage paper seismic records

Marine seismic data has been collected for several decades in both academia and industry. Early single channel acquisitions were often, if at all, recorded on magnetic media that are generally no longer supported for replay. Although seismic data over 10 years old has limited quality compared to modern acquisition, thousands of survey km of hard copy records remains world wide in areas with no recent coverage. In addition, many processed multi-channel datasets are now not available as digital files for a variety of reasons. Rising interest in continental margin geology in response to climate change priorities and the UNCLOS submission requirements of maritime states has created a demand to re-use these older records where the cost of new or re-acquisition is not pragmatic. Through creating digital SEG-Y files from images of these records they can be reprocessed and re-interpreted. This paper investigates the practicalities of paper seismic record re-use and measures the performance of a typical conversion option as an indicator of the validity of the concept. Examples of applications of the process illustrate what can be achieved and the limitations that exist so that users can make an informed choice of whether to resurrect their information.     

耐盐基因转化蓝藻Synechococcus sp. PCC 7942研究

将从极端耐盐的假单胞杆菌中克隆得到的3个基因，即转录调控因子基因，NADH脱氢酶Ⅱ基因和磷酸甘油磷酸酯酶基因转入淡水蓝藻Synechococcus sp.PCC 7942中，使受体藻对NaCl的耐受性从低于2．5％显著提高到4．5％，进一步证明了这3个基因确定与生物的耐盐性密切相关。本实验为进一步培育耐盐经济作物奠定了基础。     

大沽河口悬浮泥沙遥感模式实验研究

河口悬浮泥沙反射率渡谱特性研究是悬浮泥沙遥感定量分析的基础工作。不同水域悬浮泥沙物质成份、粒径分布和浓度的不同,其相应的反射率波谱特性也有所差异。对此,国内外尚未建立起具有普适型的算法模式,用以处理不同水域的悬浮泥沙遥感问题。鉴于此,我们于1991年9月6～11日对胶州湾大沽河口区进行了现场悬浮泥沙波谱特性实验。由此建立了大沽河口悬浮泥沙落度SSC与陆地卫星TM_3和TM_4渡段相应的光谱反射率之间的数学模式。经过相关分析和误差分析的检验证明,由模式计算所得结果是令人满意的。     

基于空间ETL实现VCT数据交换共享

本文在外部数据交换基础上,提出基于空间ETL的数据交换共享方式。采用VCT格式作为统一的数据交换格式,结合ETL数据流动的思想,对数据进行处理。本文以Geodatabase到VCT的相互转换为例,采用ArcGIS组件开发,从而实现GIS空间数据的交换共享。     

基于中国植被数据的陆面覆盖及其对陆面过程模拟的影响

本文基于中国1:100万植被图、马里兰大学AVHRR森林覆盖资料和中国753个气象站点40年的降水气温资料, 发展了一套用于气候模拟的中国陆面覆盖资料(Chinese land cover derived from vegetation map, 简称CLCV)。该套资料与CLM(Community Land Model)原来所用的MODIS (Moderate Resolution Imaging Spectroradiometer) 陆面覆盖资料相比有较大不同: 其中裸土比例减少了14.5%, 森林、灌木、草原和农作物比例分别增加了3.3%、4.8%、4.4%和0.3%, 冰川、湖泊和湿地比例分别增加了0.4%、0.8%和0.6%。将CLCV和MODIS资料分别与全国土地资源概查汇总结果分省统计资料和基于中国1 km土地利用图的土地利用资料比较表明, CLCV与两者较为接近。最后, 利用CLM模式分别采用CLCV与MODIS陆面覆盖资料在中国区域内进行数值模拟, 结果显示, 使用CLCV资料所模拟的蒸散增加了约7.7 mm/a; 地表反照率、 感热和径流分别减小了约0.7%、 0.3 W/m2和7.6 mm/a; 与MODIS卫星反演地表反照率和GRDC (Global Runoff Data Centre) 径流资料比较表明, 利用CLCV资料所模拟的地表反照率有一定改进, 并能基本模拟出径流分布趋势。     

Reflectance spectra of analog anorthosites: Implications for lunar highland mapping

Lunar highland region and associated craters are mostly composed of anorthosite. In the present study, we studied the reflectance spectra of terrestrial anorthosites collected from Sittampundi Anorthosites Complex, which is considered as equivalent (simulant) of lunar highland anorthosites. The objective of the study is to interpret diagnostic spectral features of analog anorthosite for remotely exploring lunar highland region. Reflectance spectra of anorthosites were measured under two different environments, such as controlled field and laboratory conditions. In these two procedures, the laboratory spectra give clear, diagnostic spectral information in the present study. Reflectance spectra captured under 350-2500 nm covering UV, Visible, NIR, and SWIR part of the electromagnetic spectrum. The spectral characteristics of anorthosites measured under various parts of electromagnetic spectrum have diagnostic absorption features at 380-387, 700-740, 930-1100, 1160-1200, 1415, 1920, 2200 and 2330 nm correspondingly due to plagioclase UV absorption, Fe³⁺ electron transition absorption, Fe²⁺ pyroxene and olivine absorption, OH/Mn³⁺ crystal transition absorption, pyroxene absorption, Al-OH absorption and Mg-OH absorption. Mineralogical and chemical analyses were carried out for four anorthosites and compared with the results of chemical component of lunar anorthosite. The percentage of plagioclase content, relative abundance of low and high calcium pyroxene and olivine in different anorthosite samples are correlated with the albedo range, absorption shape, absorption centers and band depth. The similarity in the diagnostic spectral features of the anolog anorthosite with lunar anorthosites could be effectively utilized for remotely mapping the lunar highland region.     

Performance of the stereoscopic system of the HEGRA imaging air erenkov telescopes: Monte Carlo simulations and observations

Based on the Monte Carlo simulations we have studied the performance of the HEGRA system of imaging air erenkov telescopes (IACTs) in its present configuration of 4 IACTs as well as in its future final configuration of 5 IACTs. Here we present the results on the basic characteristics of the IACT system which are used in the standard data analysis procedure, i.e., the collection areas, the detection rates, the angular resolution, the energy resolution, and the γ/hadron-separation efficiency. By comparing several key Monte Carlo predictions with experimental results it is possible to check the accuracy of the simulations. The Monte Carlo results concerning hadron-nuclear showers are tested with the recorded cosmic ray events and the results concerning photon-induced showers are tested with a large data sample of γ-rays observed from BL Lac object Mkn 501 during its high flaring activity in 1997. Summarizing the simulations and current observations we give the basic recommendations of using the instrument and the major values of its sensitivity.     

不连续植被二向性反射的几何光学与辐射传输一体化综合模型初探

本文论述作者对不连续植被冠层与辐射间相互作用机理研究的最新进展,提出了建立不连续植被二向性反射分布函数的几何光学与辐射传输一体化综合模型的设想和基本理论。该综合模型的建立以Li-Strahler间隙概率模型为基础,在大尺度上用纯几何光学模型反映植被的结构特征,在适于辐射传输模型的尺度上则以冠层内的间隙概率处理叶丛的截获辐射与散射。本文详细说明了冠层内任意高度的间隙率模型,也介绍了多次散射的建模方法。     

一种大地电磁成像技术

文中将层析成像技术中广泛采用的广义脉冲谱技术应用了解大地电磁 维反演成像问题,实现了电阻率剖面成像.由于在做有限元二维止演的同时,就完成了Frechet导函数的计算,从而提高了反演的速度。文中给出了模型、实例的计算,均取得了较好的效果.     

一种新的针对反射波的逆时偏移真振幅成像条件

真振幅成像是一种代表性的定量估计模型参数扰动高波数部分的地震波成像方法.经典的真振幅成像方法在高频近似和理想照明假设条件下求取显式对角Hessian逆矩阵作为偏移振幅加权算子,用以校正波传播过程中的几何扩散效应,得到模型参数扰动的带限估计.真振幅保真成像方法在利用逆时偏移（RTM）框架实现时会产生低波数噪声,影响对高波数参数估计的精度.本文给出了一种新的基于RTM框架的真振幅保真成像条件,该成像条件针对反射波数据,在高频近似下散射模式对应正问题及Bayes反问题框架下导出.与传统基于高频渐进反演的波动方程成像方法类似,利用本文提出RTM成像条件能够保证计算结果与高频近似下反演结果的一致性.同时,利用本文提出RTM真振幅成像条件能够在成像过程中自动保真的消除传统真振幅RTM算法中存在低波数噪声,模型数值实验结果验证了本文方法的正确性和有效性.