月表橄榄石含量分布制图

全月表橄榄石作为月球形成演化的指示矿物,其含量分布是月球探测研究的热点。月球卫星多光谱或高光谱数据,为利用反射光谱反演全月表橄榄石含量提供了可能。利用51组由月壤特征协会(LSCC)得出的月壤反射波谱及相应的实验室实测橄榄石含量,建立了4个反射波谱与橄榄石含量回归模型,其余6组LSCC数据作为模型验证数据。在分别解算不同模型系数的基础上,结合LSCC验证数据,比较评价不同模型标准偏差和相关系数,以及橄榄石含量分布散点图,优选出利用光谱反射率数据反演月表橄榄石含量的模型。从而利用Clementine卫星UV/VIS/NIR 5个波段的反射光谱数据反演了全月表橄榄石含量分布,通过与Apollo登月采样点实际测量橄榄石含量进行比较,验证了其结果可靠性。     

一种月壤主要矿物组分含量反演的光谱解混方法

从月壤光谱中挖掘矿物含量信息是月球遥感探测的重要内容之一,矿物光谱混合规律复杂,光谱特征对测试环境、粒度、地形、背景极为敏感是难点。提出并试验了一种基于光谱分解反演矿物含量的方法。在光谱分解前采用光谱连续统去除突出光谱谱形,分解中综合运用了光谱反射峰(介于两个吸收谷之间的光谱曲线向上凸起的部分)与吸收谷,分解后采用Hapke模型修正光谱非线性混合的影响,在混合端元光谱、端元化学成分与粒度未知情况下,实现了对月壤四种主要矿物橄榄石、斜方辉石、单斜辉石、斜长石的43条混合光谱的盲分解与矿物含量反演,反演的残差、误差、线性拟合相关系数(反演含量与真实含量)均值分别为5.0 Vol%,14.4 Vol%,0.92。该方法与反演结果可为月球高光谱矿物识别与填图提供参考与依据。     

基于Sandmeier模型的月球KAGUYA卫星高光谱数据地形校正

月球是人类深空探测的前哨站。月球卫星光谱测量是月表岩矿成分分析的主要技术方法。鉴于月表比地球地形起伏还要显著,有必要开展月球卫星高光谱数据的地形校正。通过顾及宏观地形起伏和周围地形反射辐射的影响,建立适合月表的Sandmeier辐照度模型,并由此推到了月表反射率地形校正模型。以月球虹湾地区KAGUYA卫星Spectral Profiler(SP)高光谱数据为例,借助美国Lunar Orbiter Laser Altimeter(LOLA)高程数据,计算了试验区坡度、坡向,以及入射角、反射角、地形可见因子等地形校正参数,结合平坦月表接收的太阳直接辐照度,实现了月球虹湾地区经向SP数据的反射率校正。通过比较发现,校正后反射率像元数量统计直方图近似高斯分布,而且光照区的月表反射率得到了抑制,阴影区的月表反射率有所增强,有效地消除了月表起伏地形的影响。     

基于地面试验的嫦娥五号月球矿物光谱分析仪数据质量分析

探月工程三期项目将完成“绕、落、回”三个阶段中的采样返回任务,将在未来发射嫦娥五号(CE-5)探测器,执行月面着陆、采样并返回地球的任务。嫦娥五号月球矿物光谱分析仪(LMS)是探月工程三期重要的数据来源,通过LMS光谱数据分析识别月球表面物质的矿物组成,包括含水矿物,同时有助于判断岩石类型,辅助地层学分析。为月球的形成过程、月球地质演变及岩石-水交互作用的研究提供数据支撑。相比于嫦娥三号红外成像光谱仪,LMS将光谱范围从450～2 400 nm扩展到了480～3 200 nm,除了能探测月球表面主要矿物辉石、橄榄石等,还可以探测3 000 nm附近的羟基吸收峰特征,为月球表面是否存在“水”提供强有力的证据。此外,嫦娥五号月面工作任务将获取月表以下物质,LMS可以对月表采样前后的采样区域进行光谱探测,比较不同深度、不同风化程度下的月壤光谱特征,且与后期返回样品的实验室光谱对比分析。为保证LMS月面数据的可靠性,在探测器发射之前开展了LMS地面验证试验,采用多种矿物及矿物混合样品,在不同试验环境下获取LMS的探测数据,分析研究LMS的矿物成分探测能力,并结合标准比对仪器光谱进行光谱质量分析。计算了所有实验样品的光谱不确定度参数。除了具有低反射率的钛铁矿外,所有样品都具有高质量的光谱数据。同时,在相同条件下,LMS光谱特征与标准比对仪器得到的光谱数据相一致,表明LMS整体数据质量高。     

不同病虫害危害程度下云南松针叶光谱模拟及其生化参数敏感性分析

明确植被叶片反射率对生化参数敏感程度是遥感定量反演生化参数含量的前提。本文以不同健康状态下的云南松针叶光谱为例,基于查找表法(LUT)对针叶光谱模型LIBERTY的叶绿素和水分吸收系数进行了标定。提出了一种新的光谱合成方法和枯黄指数YI,解决LIBERTY模型不能有效拟合严重受害程度的云南松针叶反射光谱曲线的问题。并应用EFAST全局敏感性分析方法,利用标定后的LIBERTY模型定量分析了不同受害程度的针叶生化参数敏感性变化。结果表明:(1)标定后的LIBERTY模型能有效拟合健康针叶光谱(R~2=0.999,RMSE0.01)、轻度(R~2=0.991,RMSE0.02)和中度受害针叶光谱(R~2=0.992,RMSE0.03);但是严重受害针叶光谱模拟能力很差(R~2=0.803,RMSE0.1)。(2)新光谱合成方法能有效拟合严重受害光谱(R~2=0.991,RMSE0.03);枯黄指数(YI)能够定量分析受害程度。(3)随着受害程度加深,针叶反射率对叶绿素、水分参数敏感度降低,而基吸收、白化吸收等参数敏感度增大,且存在敏感波段。如在505~565和705~850 nm范围白化吸收对针叶反射率作用明显;对于严重受害针叶,除了叶绿素之外白化吸收对可见光区针叶反射率影响也非常显著;通过引入白化吸收先验知识,发现如果能进一步确定白化吸收情况,能够提高严重受害针叶叶绿素反演的精度。     

基于光谱吸收特征的土壤重金属反演及吸附机理研究（英文）

土壤中的重金属含量较少,难以在光谱曲线上表现出明显的特征,现有的土壤重金属反演实验多是通过统计的方法寻找重金属的敏感波段,不能准确解释土壤重金属的反演机理,难以建立土壤重金属反演的普适性模型,通过分析铁锰氧化物、有机质、粘土矿物在土壤光谱曲线上的吸收特征,深入研究了土壤重金属对可见光近红外光谱的影响,分析了褐土中的重金属反演机理。以徐州试验田为例,共采集80个土壤样本。首先,利用ASD地物光谱仪测定土壤样本的光谱反射率,并采用电感耦合等离子体质谱仪检测土壤样品中的Cr, Cd, Cu, Pb和Zn的含量。然后,土壤光谱经过包络线去除处理,与重金属相关的吸收峰在480, 1 780和2 200 nm附近,所显现的吸收峰主要受土壤中的铁锰氧化物、有机质、粘土矿物的影响。在吸收峰位置提取了光谱吸收特征的四个参数:Depth_(480), Depth_(1 780), Depth_(2 200)和Area_(2 200),分析了它们随五种重金属含量变化的增减趋势,发现四个参数数值与五种重金属含量有很强的相关性。分析单个变量反演重金属发现,参数Depth_(480)反演Cr和Pb的效果较好,参数Area_(2 200), Depth_(1 780)反演Cd, Cu和Zn的效果比较好。同时使用四个光谱吸收特征参数,利用最小二乘法、岭回归法、支持向量回归法求取回归系数,建立的五种重金属含量的反演模型比使用单变量建立的反演模型预测能力强且稳定,五种重金属Cr, Cd, Cu, Pb和Zn反演效果最好的验证集决定系数分别是0.71, 0.84, 0.92, 0.80, 0.89。结果表明,在此研究区域Cr和Pb容易被铁锰氧化物吸附,而Cd, Cu和Zn更容易被有机质、粘土矿物吸附。此研究为探究土壤光谱特征与土壤重金属含量之间的关系提供了参考。     

星载大气痕量气体差分吸收光谱仪狭缝函数研究

星载大气痕量气体差分吸收光谱仪是一种新型光学遥感仪器,具有分辨率高(0.3～0.5 nm)、宽光谱范围(240～710 nm)、大视场角(114°视场对应地面2 600 km)的特点,载荷采用推扫方式,可实现1日全球覆盖监测。载荷通过探测地球大气或地表反射、散射的紫外/可见光,利用差分吸收光谱技术来获取全球大气痕量气体(NO₂, SO₂, O₃等)分布和变化。定标是遥感数据定量应用的前提,同时为获取载荷光谱特性,需要在地面完成载荷的光谱定标。根据大气痕量气体差分吸收光谱仪视场角度大、谱段范围宽、空间和光谱分辨率高等特点,搭建了一套基于二维转台的光谱定标系统,此系统能够完成全视场光谱定标。光谱定标采用标准谱线法,光谱定标光源使用汞灯。光谱响应函数是描述光谱仪光谱响应特性的重要参数,根据光谱响应函数可以获取载荷的光谱分辨率,同时也是基于DOAS反演的关键输入参数,光谱响应函数的精度直接影响大气痕量气体的反演结果。根据载荷实际测试的光谱响应数据,选取了Gauss,Lorentz和Voigt三种函数作为待选的光谱响应函数。为对三种函数模型进行筛选,进行了两种筛选对比测试,首先分别用Gauss函数、Lorentz函数、Voigt函数对载荷的单色光响应数据进行拟合,以三种函数的拟合残差平方和作为评判标准,拟合结果表明Gauss函数作为狭缝函数拟合的残差平方和最小为0.01,Lorentz和Voigt函数作为狭缝函数拟合的残差平方和分别为0.033和0.021。从载荷单色光响应数据函数拟合的结果分析,Gauss函数可以作为载荷的光谱响应函数模型。为了进一步验证这一结论,进行了DOAS反演NO₂样气的实验,考察三种函数模型对反演的影响。在实验室开展了NO₂样气测试,大气散射光通过30*40cm的石英窗口入射到载荷狭缝,将NO₂样品池放置在载荷狭缝和石英窗口中间,获取的数据为NO₂样气吸收谱,随后充入N₂气体获取反演的参考谱,实验在晴朗天气下进行,并能够在较短时间内完成,可以减少外界天气条件对反演结果的影响。实验中NO₂样气浓度为8.481 2×1016 molec·cm-2,在利用DOAS进行反演时,设置仪器狭缝函数分别为Gauss,Lorentz和Voigt函数,分析三组不同的函数模型对应的NO₂浓度结果,根据反演结果的相对偏差对函数模型进行评价。实验结果表明Gauss函数作为狭缝函数反演结果的相对偏差最小为5.6%,Lorentz和Voigt函数作为狭缝函数的反演相对偏差分别为28%和15.1%。由光谱响应数据的拟合结果及样气反演结果表明,Gauss函数可以作为载荷的光谱响应函数模型。     

工矿业城市区域水质参数高光谱定量反演

工矿业城市区域易受工业活动、矿产开采影响,使其水环境遭受不同程度的破坏,以至于水体污染问题突出。当前常规水质监测主要采用“以点代面”的工作方式进行野外采样及其室内化验分析,然而环境复杂多变,空间差异大,导致调查点代表性受限,整体精度不高,效率低下,更难以实现区域性动态监测。以因矿兴市的矿业重镇湖北黄石大冶市为研究区,同步开展无人机高光谱航飞、地面光谱测量和水体样品采集测试,分别获得具有49个波段的高光谱影像数据和光谱分辨率为1 nm的水体光谱曲线,其中影像数据波谱范围为505~890 nm,光谱分辨率为7.78 nm,空间分辨率为30 cm。对获取的高光谱影像和光谱数据剔除异常值、光谱定标、辐射校正等预处理后,对比分析研究区内水体的不同光谱吸收、反射及光谱曲线形态特征信息,从而提取出高光谱影像和测量光谱的反射光谱曲线形态特征、去包络线后光谱曲线形态特征、三阶求导后光谱曲线形态特征和光谱四值编码共四大类25个光谱特征。采用皮尔森相关系数分析样品水质参数与光谱特征之间的相关性,以此筛选出存在显著相关的水质参数与光谱特征。在此基础上,采用逐步回归分析方法筛选出最大反射率及其波长位置、对称度、光谱编码Ⅲ、三阶导最大及最小值等光谱特征作为模型变量,构建出水质参数的多元线性反演模型,并对模型进行F检验和t检验。将检验后的反演模型推广运用于研究区内高光谱影像,获得尾矿库、河流、湖泊等典型区域的水质参数反演结果,从而实现“由点到面”水质参数信息的快速获取。结果显示水质参数pH、硬度（Ca2++Mg2+）、钾与氯离子比值（K+/Cl-）、镁与碱度比值[Mg2+/(HCO3-+CO2-₃)]的反演精度较高,其pH的判定系数R2最小为0.669,镁与碱度比值的判定系数R2最大为0.895,相对均方根误差均小于28%;而总溶解固体（TDS）反演精度较低,其判定系数R2仅为0.463,相对均方根误差达36.762%。提出了一种基于光谱曲线形态特征的高光谱遥感水质参数定量反演模型方法,实现了pH值、硬度、镁离子与碱度之比等水质参数的高光谱定量反演,为区域水环境动态监测提供了新方法。     

利用光谱吸收深度定量反演碳酸盐矿物的影响因素及应用分析

光谱吸收特征是矿物识别与定量反演的重要指标。为提高利用光谱吸收特征定量反演矿物精度,以方解石为代表,以线性混合光谱模型与连续统去除方法为基础,以连续统去除吸收深度(CRBD)为分析对象,按端元光谱在2.33 μm附近有无吸收特征对光谱进行分类,并分析每类数据与方解石混合光谱CRBD随丰度、反射率以及光谱特征等影响因素的变化规律,进而非线性拟合其变化范围并提出一种新的矿物含量表示方法。研究结果表明,端元丰度对CRBD值影响较大,方解石丰度越大,吸收特征越明显,CRBD值越大。同样,混合端元反射率与光谱特征对混合光谱CRBD值影响也较明显,当混合端元光谱在2.33 μm附近为无特征时,端元光谱反射率越小,CRBD随碳酸盐丰度变化上凸越明显,为反射峰特征时,端元光谱反射率越大,下凹越明显;混合端元在2.33 μm附近为吸收谷特征时,CRBD随碳酸盐丰度接近线性变化。通过交叉分析与多端元混合光谱CRBD变化分析发现,混合光谱CRBD随碳酸盐矿物丰度及混合端元反射率变化受限于一定范围,其上限拟合方程满足指数函数变化,下限拟合方程为三次多项式函数,且拟合精度较高,R2均高于0.99,RMSE低于0.005。为实现矿物含量的精确预测,根据拟合方程提出一种以变化范围替代定量值来表示碳酸盐矿物丰度分布的方法,实现碳酸盐矿物含量反演的范围表示。通过影响因素分析及范围表示法可为矿产监测、定量评估等提供新的表达方法,为建立具有普适性的地物定量反演模型提供理论参考。     

基于分子转-振光谱精细结构的火焰温度遥测方法

燃烧火焰温度是固体推进剂等重要参数,本文研究了基于分子转-振光谱精细结构的火焰温度遥测方法.根据分子转-振光谱线的展宽机制,研究了分子谱线线型.结合朗伯-比耳吸收定律,去除谱线中心受大气低温气体吸收影响较大的数据点后,利用谱线两翼的数据点进行谱线线型拟合,利用分子转-振光谱精细结构温度遥测方法将经拟合修正后数据反演火焰...     

Bouguer gravity anomaly of the Moon from CE-1 topography data: Implications for the impact basin evolution

In this study, the terrain correction for lunar free-air gravity anomaly (FAGA) is calculated in spherical coordinates based on the global topography data detected by the laser altimeter on Chang’E-1 (CE-1). The obtained lunar Bouguer gravity anomaly (BGA) reveals density irregularities of the interior mass. BGA is important in characterizing the mascon basins. According to the BGA of the Moon, the South Pole-Aitken (SPA) basin is considered the largest mascon basin on the Moon, and the feature of BGA in the basin implies the impacting direction. Further, the mascon basins seem to be classified into two types, Type Highland and Type Plain. For the mascon basins of Type Highland the dense materials mainly come from the shallow crust, which are associated with the basalt deposits. The other type, Type Plain, includes mascon basins whose major dense materials may be located deep at the lithosphere, corresponding to the uplifted mantle.     

The improvement of cross-calibration of IIM data and band selection for FeO inversion

Chang’E-1 (CE-1) Interference Imaging Spectrometer (IIM) dataset suffers from the weak response in the near infrared (NIR) bands, which are the important wavelength for retrieving the minerals and elements of the Moon. In this paper, the cross-calibration was implemented to the IIM hyperspectral data for improving the weak response in NIR bands. The results show that the cross-calibrated IIM spectra were consistent to the Earth-based telescopic spectra, which suggests that the cross-calibration yields acceptable results. For further validating the influence of the cross-calibration on the FeO inversion and searching the optimal bands to retrieve lunar FeO contents, four band selection schemes were designed to retrieve FeO using the original and cross-calibrated IIM spectra. By comparing the distribution patterns and histograms of the IIM derived FeO contents with the Clementine derived FeO, the IIM 891 nm band after cross-calibration showed a higher accuracy in the FeO inversion, hence most useful for lunar FeO inversion.     

Double lunar swing-by orbits revisited

The double lunar swing-by orbits are a special kind of orbits in the Earth-Moon system.These orbits repeatedly pass through the vicinity of the Moon and change their shapes due to the Moon’s gravity.In the synodic frame of the circular restricted three-body problem consisting of the Earth and the Moon,these orbits are periodic,with two close approaches to the Moon in every orbit period.In this paper,these orbits are revisited.It is found that these orbits belong to the symmetric horseshoe periodic families which bifurcate from the planar Lyapunov family around the collinear libration point L3.Usually,the double lunar swing-by orbits have k=i+j loops,where i is the number of the inner loops and j is the number of outer loops.The genealogy of these orbits with different i and j is studied in this paper.That is,how these double lunar swing-by orbits are organized in the symmetric horseshoe periodic families is explored.In addition,the 2n lunar swing-by orbits(n≥2)with 2n close approaches to the Moon in one orbit period are also studied.     

Absolute calibration of the Chang’E-1 IIM camera and its preliminary application

The interference imaging spectroradiometer (IIM) onboard the first lunar satellite of China “Chang’E-1” can now provide approximately global high spectral and spatial resolution reflectance spectra of the Moon. It is the essential instrument with which to accomplish one of the four missions of the first lunar satellite of China. As the current data provided by the Lunar Exploration Program Center and National Astronomical Observatories (NAOC) are not reflectance and the sensor response is inhomogeneous in the line direction, users can not use the current data directly. Moreover, due to the narrow band range, IIM data cannot cover the absorption peak of the mafic minerals of the Moon completely, which limits its ability for identifying minerals. The main objective of this study is to describe the methods for absolute calibration, correction and acquiring the absorption center of minerals for IIM data. The results from our study show that in the space domain the sensor response decreases toward the left, and in the spectral domain the response of the longer bands is more inhomogeneous than that of the shorter bands. After the calibration and correction, the reflectance of IIM matches the earth-based telescopic spectra well, which suggests the possible use of the processed data in the geological research. A high correlation was found between the absorption center and the wavelength at which the first derivative equals 0, i.e., the so-called Stagnation Point in the mathematical sense. In the end, we show a preliminary applied study of the two craters with diameter larger than 35 km using the calibrated data. The spectra of IIM data show that the lunar crust has compositional diversity within the km scale. Pure anorthosite may be found on the wall and floor of the Aristarchus crater with the map of absorption center, which indicates that anorthosite is ubiquitously present within the lunar crust. IIM, with its capacity to acquire lunar composition at the regional and global scale, will contribute to the research of lunar origin and evolution.     

Impacts of fast meteoroids and a plasma–dust cloud over the lunar surface

The possibility of the formation of a plasma–dust cloud in the exosphere of the Moon owing to impacts of meteoroids on the lunar surface is discussed. Attention is focused on dust particles at large altitudes of ~10–100 km at which measurements were performed within the NASA LADEE mission. It has been shown that a melted material ejected from the lunar surface owing to the impacts of meteoroids plays an important role in the formation of the plasma–dust cloud. Drops of the melted material acquire velocities in the range between the first and second cosmic velocities for the Moon and can undergo finite motion around it. Rising over the lunar surface, liquid drops are solidified and acquire electric charges, in particular, owing to their interaction with electrons and ions of the solar wind, as well as with solar radiation. It has been shown that the number density of dust particles in the plasma–dust cloud present in the exosphere of the Moon is ?10^?8 cm^?3, which is in agreement with the LADEE measurements.     

The interpretation of gravity anomaly on lunar Apennines

The lunar Apennines, located in the southeast of Mare Imbrium, is the largest range on the Moon. The gravity anomalies on profiles across the mountains reveal evidence of a great fault zone characteristic. The deep crustal structures of lunar Apennines are analyzed on the basis of topographic data from Chang’E-1 satellite and gravity data from Lunar Prospector. The inverted crust-mantle models indicate the presence of a lithosphere fault beneath the mountains. Inverted results of gravity and the hypothesis of lunar thermal evolution suggest that the lunar lithosphere might be broken ∼3.85 Ga ago due to a certain dynamic lateral movement and compression of lunar lithosphere. This event is associated with the history of magma filling and lithosphere deformation in the mountain zone and adjacent area. Moreover, the formation and evolution of Imbrium basin impose this effect on the process.     

Lunar terrain and mineral's abundance automatic analysis

The image is the important data in the lunar exploration. The main objective of this work is to detection lunar craters with the multi-information fuzzy logic method, and to quantify the image's terrain and the abundance of lunar surface minerals based on crater distribution law and soil characterization consortium data set with lunar surface reflectance. We implement image processing to recognize lunar crater and analysis lunar terrain; use lunar reflectance model to solve mineral reflectance question; joint commonly used look-up lunar reflectance tables and least squares to solve lunar surface reflectance questions; and calculate the minerals reflectance, region reflectance, and then estimate abundance of lunar surface soil minerals. An actual lunar image (Apollo 15 landsite, Clementine mission) of Mare region as an example, this method analysis results of the terrain and mineral's abundance are basically same with published literature. In the future, this method can be simple rapid in-time implemented in real-time lunar exploration.     

Mössbauer and VNIR study of dust generated from olivine basalt: application to Mars

Mössbauer spectroscopy of surface rocks, soil, and dust on Mars from the Mars Exploration Rovers (MER) suggests that the mineral olivine is widespread on the surface. Detection of the mineral by near-IR optical spectroscopy from Martian orbit indicates that it is found in relatively small isolated outcrops concentrated in the floors and rims of craters distributed around the ancient cratered highlands of Mars. To shed light on this apparent paradox, we have performed a detailed Mössbauer and visible-near-IR (VNIR) investigation of dust generated from Icelandic olivine basalt, which is a good Mössbauer analogue to the igneous rocks at Gusev crater on Mars. The results show that the amount of olivine relative to pyroxene can be underestimated by almost an order of a magnitude in VNIR reflectance spectra, most probably because of the longer effective optical path length in pyroxene compared to olivine.     

New features of the Moon revealed and identified by CLTM-s01

Previous analyses showed a clear asymmetry in the topography, geological material distribution, and crustal thickness between the nearside and farside of the Moon. Lunar detecting data, such as topography and gravity, have made it possible to interpret this hemisphere dichotomy. The high-resolution lunar topographic model CLTM-s01 has revealed that there still exist four unknown features, namely, quasi-impact basin Sternfeld-Lewis (20°S, 232°E), confirmed impact basin Fitzgerald-Jackson (25°N, 191°E), crater Wugang (13°N, 189°E) and volcanic deposited highland Yutu (14°N, 308°E). Furthermore, we analyzed and identified about eleven large-scale impact basins that have been proposed since 1994, and classified them according to their circular characteristics.