长波天波授时可行性分析

为扩展现有长河二号系统的授时覆盖范围,提出利用天波实现远距离授时。结合实测数据以及长波天波场强和时延理论算法,分析了天波场强和时延随传播路径及昼夜变化的规律,并通过天地波场强的对比验证了利用天波授时的可行性。     

在大数据背景下看TAS分类的不足及可能的解决方案

火山岩TAS分类是国际地质科学联合会在1989年第28届国际地质大会上通过的,迄今已经40年了。该分类对推进岩石学和地球化学的研究起了积极的作用,规范了岩石(尤其火山岩)的命名,方便了学术界的交流。但是,不能不承认,早先的研究,由于分析方法、分析技术以及数据量的限制,是存在某些局限性的。现在,全球已积累了海量的数据,应当有条件对火山岩的分类做一个新的探讨了。文中讨论了TAS分类的初衷、分类的原则及存在的问题,推出了新的TAS分类方案。早先的分类一共划分了15个岩区,新的方案压缩为10个,其中9个保留了早先的命名,新增一个碱流岩区。新的TAS图最大的变化在碱性岩系列,在新的TAS图中,碱性岩系列呈"人"字形分布,把粗玄岩系列封闭起来,弥补了早先的TAS分类在酸性岩部分的不足,还发现TAS图理论上可能存在的一些问题。本文的探讨是初步的,只是抛砖引玉,希望能够引起学术界的关注,开启利用大数据方法对TAS分类的新的研究。     

Ultraviolet radiation in overcast sky at the surface

Based on the analysis of one year of observation data of solar radiation at the ground in Beijing in 1990, a simple empirical formula for calculating UV radiation in overcast sky is established. The formula is Qlw/Quvo = A1S Ao, where Quv and Quvo are monthly mean daily sums of UV exposure in overcast sky and clear sky, respectively. S is the daily sunshine hours. The calculated results agree well with the observed. The maximum and minimum relative biases are 9.9% and 0.1%, respectively, and the yearly relative bias is 2.9%. The ratio of ultraviolet radiation of overcast sky to clear sky in 1990 is between 44.6% and 61.8%, and the yearly average is 53.9%. Thus, almost half of the UV energy is lost in the atmosphere in overcast sky in 1990.     

云量定量测算

现行云量观测各种误差较大，本文提出了天空（即天空视野）为半球形，把无法器测的云量转换成可以器测的云块视高度和视宽度角的测量，利用数学方法定量计算云量，以减小观测误差，提高观测精度。     

STUDYING THE SKY RADIANCE AND DEGREE OF POLARIZATION AND SOUNDING THE OPTICAL CHARACTERISTICS OF ATMOSPHERIC AEROSOL

The sky radiance and degree of polarization with multiple scattering process considered were calculated inthis paper by solving vector form radiative transfer equation iteratively. Numerical experiment for simultaneouslyretriving the size distribution (SD) and the complex refractive index (CRI) of aerosol particle was conductedwith the degree of polarization of skylight (DPS) and the library method used. It is shown from the resultsthat the real part of CRI is always sensitive to DPS. But situation is somewhat complicated for the imaginarypart of CRI. Therefore, it is expected that the real part of CRI can be retrieved from DPS and its imaginarypart should be retrieved as the particle is large in size. In this paper, seven sets of DPS measurements on 6 January,1990 in Beijing were given and the optical characteristics of aerosol were retrieved.     

[1H] and [13C]NMR studies on the importance of aromatic structures in fulvic and humic acids

To obtain information on the contribution of aromatic fragments to the chemical structure of humic substances, we carried out a study on the [¹H]NMR and [¹³C]NMR spectra of humic and fulvic acids and their oxidative degradation products extracted from an Andosol soil.[¹H]NMR spectra of all organic fractions present considerable adsorption between 7.4 and 8.8 ppm, due to the presence of aromatic protons.The percentages of aromatic protons in respect to the total amount of protons are as follows: FA 20%, HA 19%, degraded FA < 12%, degraded HA 14%. The values indicate that the contribution of aromatic structures to the humic substances is significant, also considering that they are highly substituted.The degraded fractions contain smaller amounts of aromatic protons, because degradation causes the opening of the aromatic rings. Thus results obtained from the degradation do not seem to be reliable for defining the importance of aromatic structures in humic substances.Also the [¹³C]NMR spectra show signals in the aromatic region which derive from unsubstituted carbon atoms, while signals originating from tertiary carbon atoms merge with the noise. We believe that, at present, [¹H]NMR spectroscopy is more suited for studying the role played by aromatic compounds in organic soil fractions.     

消除CCD天光背景的一种组合式分割方法

基于迭代阈值法和统计模型提出了一种新的组合式分割方法，该方法精确地描述了天光背景的分布情况，既能够精确确定图像分割的最优阈值，有效地消除天光背景的影响，又可以精确地估计出天光的平均强度，有利于天体亮度的精确计算及暗星的探测。     

华东地区大气臭氧总量的变化特点

分析了１９９３年１２月至１９９４年１１月的大气臭氧总量资料并与同纬度全球平均值进行比较，分析了大气臭氧总量的年变化、日变化和季节变化。结果表明，臭氧总量的年变化中有双峰特征，它的日变化则以中午时较高，早晚较低；季节变化以春季高，冬季低，与大气透明度的关系较为密切     

应用二向性反射分布函数进行反照率的精确计算和邻近象元效应校正(英文)

该文讨论二向性反射分布函数（ＢＲＤＦ）在遥感领域中两方面的应用：（１）晴天大气层顶部的反照率的确定，（２）二向性反射分布函数对邻近象元点扩散函数和大气订正的影响。大气层顶部的光谱反照率是从多角度成象光谱辐射计（ＭＩＳＲ）提取的重要参数，其精度主要取决于我们对不同情况表面建立更好的ＢＲＤＦ模型。该文论述一种与９个ＭＩＳＲ二向性反射观测值相匹配的半经验函数的算法，并可进而通过数值积分产生４个光谱波段的晴天大气层顶部的光谱反照率。结果显示反照率的绝对精度对可见光波段可高于１％，对近红外波段可高于２％。采用一种简化的辐射通量模型，我们的工作显示邻近象元点扩散函数（ＰＳＦ）的形状取决于下垫面表面的ＢＲＤＦ。在给定与中心象元的偏移（ｘ，ｙ）的条件下邻近象元的点扩散函数，由和沿观察方向的散射相函数的传输加权的乘积的积分给定。     

矿井全方位钻孔测斜仪的数值计算与误差校正

本文论述了矿井全方位钻孔测斜仪的测量原理，数值计算方法和误差分析校正