SOME KEY ISSUES ON THE APPLICATION OF SATELLITE REMOTE SENSING TO MINING AREAS

In order to apply Satellite Remote Sensing(RS) to minig areas,some key issues should be solved,Based on an introduction to relative studying background,related key issues are propsed and analyzed oriented to the devel-opment of RS information science and demands of mining aress ,Band selection and combination optimization of Landsat TM is discussed firstly,and it proved that the combination of Band 3 ,Band 4 and Band 5 has the largest informaiton amount in all three-band combination schemes by both N-dimensional entropy method and Genetic Algorithm(GA) ,After that the filtering of Radarsat image is disccussed ,Different filtering methods are experimented and compared,and adaptive methods are more efficient than others,Finally the classification of Satellite RS image is studied,and some new methods including classification by improved BPNN (Back Propagation Neural Network) and classification based on GIS and knowledge anre propsed.     

LAGEOS II perigee rate and eccentricity vector excitations residuals and the Yarkovsky-Schach effect

We have analysed LAGEOS II perigee rate and eccentricity vector excitation residuals over a period of about 7.8 years, adjusting and computing the satellite orbit with the full set of dynamical models included in the GEODYN II software code. The long-term behaviour of these orbital residuals appears to be characterised by several distinct frequencies which are a clear signature of the Yarkovsky-Schach perturbing effect. This non-gravitational perturbation is not included in the GEODYN II models for the orbit determination and analysis. Through an independent numerical analysis, and using the new LOSSAM model to represent the spin-axis behaviour of the satellite, we propagated the Yarkovsky-Schach effect on LAGEOS II perigee rate and compared the results obtained with the orbital residuals. We have thus been able to satisfactorily fit the amplitude of the Yarkovsky-Schach effect to the observed residuals. Our approach here has proven very successful with very positive results. We have been able to obtain a fractional reduction of about 40% of the post-fit rms with respect to the pre-fit value. When analysing the eccentricity vector residuals, we have been able to obtain a better result in the case of the real component, with a fractional reduction of the post-fit rms of about 49% of the initial value. The analysis of the effect's imaginary component in the eccentricity vector rate is more complicated and deserves additional scrutiny. In this case we need a deeper study which includes the analysis of other unmodelled and mismodelled effects acting on the imaginary component. The study performed in this paper will be of significant relevance not only for the geophysical applications involving LAGEOS II orbit analysis, but also for a refined re-analysis of the general relativistic precession produced by the Earth angular momentum, i.e., the Lense-Thirring effect.     

利用卫星遥感动态监测资料加快土地利用数据库的更新

烟台市福山区在1：1万土地利用数据库的基础上，利用法国SPOT-5卫星遥感监测资料对土地利用数据库进行更新，将历年的变更资料人数据库，统一更新到2002年度。高分辨率卫星遥感图像的应用能为土地信息系统的建设和数据库的更新提供多源、多尺度、实时、丰富的信息源，保证土地利用基础资料的现势性和可靠性。     

Cassini VIMS observations of the Galilean satellites including the VIMS calibration procedure

The Visual and Infrared Mapping Spectrometer (VIMS) observed the Galilean satellites during the Cassini spacecraft's 2000/2001 flyby of Jupiter, providing compositional and thermal information about their surfaces. The Cassini spacecraft approached the jovian system no closer than about 126 Jupiter radii, about 9 million kilometers, at a phase angle of <90°, resulting in only sub-pixel observations by VIMS of the Galilean satellites. Nevertheless, most of the spectral features discovered by the Near Infrared Mapping Spectrometer (NIMS) aboard the Galileo spacecraft during more than four years of observations have been identified in the VIMS data analyzed so far, including a possible ¹³C absorption. In addition, VIMS made observations in the visible part of the spectrum and at several new phase angles for all the Galilean satellites and the calculated phase functions are presented. In the process of analyzing these data, the VIMS radiometric and spectral calibrations were better determined in preparation for entry into the Saturn system. Treatment of these data is presented as an example of the VIMS data reduction, calibration and analysis process and a detailed explanation is given of the calibration process applied to the Jupiter data.     

Discovery of co2 ice and leading-trailing spectral asymmetry on the uranian satellite ariel

New 0.8- to 2.4-μm spectral observations of the leading and trailing hemispheres of the uranian satellite Ariel were obtained at IRTF/SpeX during 2002 July 16 and 17 UT. The new spectra reveal contrasts between Ariel’s leading and trailing hemispheres, with the leading hemisphere presenting deeper H₂O ice absorption bands. The observed dichotomy is comparable to leading-trailing spectral asymmetries observed among jovian and saturnian icy satellites. More remarkably, the trailing hemisphere spectrum exhibits three narrow CO₂ ice absorption bands near 2 μm. This discovery of CO₂ ice on one hemisphere of Ariel is its first reported detection in the uranian system.     

有线光纤电视综述

有线电视ＣＡＴＶ正在迅速深入千家万户。有线光纤电视网将是２１世纪地面的主要广播形式。“信息高速公路”是将电脑、电话、电视结合在一起的通信网络。有线光纤电视网是“信息高速公路”的重要组成部分之一     

The strength of the lunar lithosphere

A self-gravitating, elastic, spherical thick shell model is used to derive the present state of the lateral variations of density and stress differences within the lunar lithosphere. The model is allowed to deform under the load of an initial surface topography and internal density distribution, such that the resulting deformed body gives rise to the observed surface topography and gravity specified by the spherical harmonics of degree up to 70. Two main models are considered, Model A and Model B, with elastic lithospheres of thickness 300 and 210 km, respectively. Model A displays density perturbations of generally less than ±200 kg/m³ within the crustal layers, reducing rapidly to less than ±20 kg/m³ at the base of the lithosphere. The density perturbations in Model B are similar in the crust and marginally higher at the base of the lithosphere. The major stress differences in the mantle are associated with the mascon basins and are found to reach maximums of 8-10 MPa within the lower lithosphere (150-270 km) of Model A and maximums of 12-16 MPa at 150 to 180 km depth for Model B. A moderate correlation exists between the modeled stress distributions and shallow moonquake epicenters. However, the overall results of this study imply that other remnant stresses, due to processes other than density perturbations, exist and play a critical role in the large shallow moonquakes.     

辽宁省2000国家大地坐标框架的建立

2000国家大地坐标系是我国自主建立、适应现代空间技术发展趋势的地心坐标系。辽宁省2000国家大地坐标框架的建立,可以实现与国家现代测绘基准体系的无缝对接,对测绘事业的发展和基于全球导航卫星系统(GNSS)技术的高精度位置服务产生重大影响和作用。本文主要讲述了辽宁省2000国家大地坐标框架建设取得的进展,介绍了坐标框架建立过程中的关键技术应用以及对辽宁省测绘基准体系建设和测绘科技发展的推动作用。     

北斗反射信号海风探测数据分析与检定

利用导航卫星反射信号(GNSS-R)进行海风海浪探测为海洋气象提供了一种新的观测手段,数据分析及有效性检定是确定系统探测能力的重要过程.在描述北斗GEO卫星进行海风探测机理的基础上,利用北斗反射信号的相关时间进行了海风的反演.同时针对国家北斗应用项目"基于北斗导航卫星的大气海洋和空间监测预警应用示范工程"在山东进行试验和试运行期间产生的风速观测数据进行分析,并通过与标准数据的对比,确定了该方法的有效性.     

东亚夏季气溶胶—云—降水分布特征及其相互影响的资料分析

东亚季风气候受到自然因素和人类活动的共同影响,而人类活动因子中气溶胶的作用尤为关键,采用诊断分析的手段研究东亚地区气溶胶的特征及其与云和降水的相互关系具有重要的科学意义。本文利用MODIS(moderate-resolution imaging spectroradiometer)气溶胶和云资料以及TRMM(Tropical Rainfall Measuring Mission)降水数据,分析了东亚夏季气溶胶、云、降水的时空分布特征,研究了气溶胶与云和降水的相互关系。结果表明:中国四个典型地区(珠三角、长三角、四川盆地、京津唐)2001～2011年夏季(6～8月)平均气溶胶光学厚度(Aerosol Optical Depth, AOD)变化范围为0.40～0.68,云光学厚度平均值为18.7～23.6,水云云滴有效粒子半径在20.2～25.6 μm,冰云有效粒子半径在12.9～15.3 μm,云水路径为222.2～243.8 g m-2,降水强度平均值3.6～8.6 mm d-1;珠三角气溶胶光学厚度有显著降低趋势,年倾向为-3.31%,四川盆地云滴有效粒子半径(冰云、水云)和云水路径年变化趋势为-0.42%、-0.49%和-1.26%,京津唐夏季降水量年增幅为3.24%。气溶胶光学厚度和云光学厚度呈正相关,相关系数最大为0.77;在相对湿度较低(30%～50%)情况下,气溶胶光学厚度与云滴有效粒子半径呈负相关;气溶胶光学厚度与云水路径呈正相关,相关系数最大为0.92;相对于低污染情况(AOD<0.5),高污染情况(AOD>0.5)下出现大雨(>10 mm d-1)的频率增加了6.6%～19.1%,小雨(<1 mm d-1)的频率减少了0.72%～7.3%。在水汽含量较少的情况下,气溶胶的增加导致云滴有效粒子半径的减少;气溶胶增强了南方地区的对流性降水,抑制了北方地区层云降水。