最新刊期
卷 ， 期 3 ， 2000
- 摘要：Cloud liquid water path （ L ） （i.e. vertically integrated cloud liquid water） is an important parameter in meteorology and in the study on cloud radiation interaction. It has already been demonstrated that the space borne microwave radiometer is a powerful tool for monitoring the distribution and variation of L on global scale. However, the L retrieval algorithm for on orbit SSM/I still has to be improved or renewed, and in parallel the algorithm is being developed for AMSR on board the ADEOS Ⅱ which will be launched in the near future. The aim of this work is to develop an algorithm for determining over ocean cloud L using the physico statistical method. A simple relationship is obtained between liquid water path and the difference of brightness temperatures （Δ T B） in cloudy and clear atmospheres from the simulation data with a radiative transfer model. In the algorithm, only the relationship L Δ T B in channel of vertically polarized 37 GHz （37 V） is used because it has smaller rms error. The T B at 37 V in ‘clear’ atmosphere is derived through a relationship with T B at 19.35 V obtained by regression of SSM/I observation data in really clear atmospheres. The L results retrieved from SSM/I measurements by the present algorithm and two other algorithms are compared to the ISCCP L data. It is shown that the present L retrieval algorithm yields quite reliable retrievals of cloud liquid water path.关键词：space borne microwave radiometer;cloud liquid water path;retrieval algorithm development
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发布时间：2021-06-10 - 摘要：A simulation model for the radar backscattering cross section of the sea surface has been developed based on the radar imaging mechanism of underwater bottom topography. The model consists of the Navier Stokes equation, the action balance equation and the radar backscatter model. The simulation model is solved numerically using the method of characteristics. The results of the simulation model have been used to study the optimal SAR parameters （frequency, polarization and incidence angle） for mapping underwater bottom topography. It is shown that long wavelengths are required. P band is the optimal band for mapping underwater bottom topography, followed by L, C and X bands. Although mapping underwater bottom topography is independent of the polarization, the VV polarization is the best choice because of its large signal to noise ratio. The incidence angles between 20° to 40° are needed to map underwater bottom topography by spaceborne SAR.关键词：simulation;underwater bottom topography;radar parameters
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发布时间：2021-06-10 - 摘要：Different land surface feature and physical characteristics cause anisotropy energy distribution. They influence on regional and global climate change because of snow wide distribution, high albedo and continuous seasonal change. Remote sensing which monitors the change of land surface feature and derives regional albedo is an effective measure. In this paper, we study dynamic distribution of snow and dynamic change of albedo through remote sensing technology.关键词：albedo;land surface feature models
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发布时间：2021-06-10 - 摘要：Reciprocity in the sense of “when the Sun and detector change position, the observed reflectance should remain the same”, its validity is tested using ADEOS POLDER level 2 data. Geometrically reciprocal （GR） pairs of data are selected from nearly a months observation of the sample region. It is found that some of these GR pairs have considerable non reciprocity, and ignoring this non reciprocity can cause up to 0.2’s uncertainty in the calculation of NDVI. Besides in ratio to wavelength, the magnitute of non reciprocity also shows a sign of correlation with NDVI and altitude. It seems that with IR bands and low NDVI , visible bands and high NDVI , IR bands and high altitude, the data show more non reciprocity.关键词：reciprocity;BRDF;POLDER
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发布时间：2021-06-10 - 摘要：Temperature and emissivity are defined for homogeneous and isothermal surfaces. However, natural land surfaces are neither homogeneous nor isothermal. The directional effects of thermal emission can not be neglected. We developed a model to describe the directional emission of vegetation canopies in thermal infrared band based on a conceptual model. The complex nonisothermal land surfaces are separated as homogeneous and isothermal components with distinct temperature in this model. A nonisothermal leaf canopy is modeled and inverted in this paper as an illustration. By statistical analysis of the inversion results, it is shown that this model is robust to noises. When a priori guesses for the component temperatures have errors of 2K and the noise equivalent temperature difference （ NE Δ T ） in the observations is about 0.29K, the mean inverted temperatures have biases of 0.08K and 0.24K for the top and bottom layer respectively. The standard deviations of the inversion results are 0.15K and 0.48K respectively.关键词：component temperature;emissivity;directional emission;inversion
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发布时间：2021-06-10 - 摘要：The general expression about \%SNR\% of Spatially Modulated Imaging Fourier Transform Spectrometer is deduced in detail, and Sagnac type Imaging Fourier Transform Spectrometer is chosen as analysis model. The relationship between affection factors and \%SNR\% is analyzed and corresponding conclusion is obtained.关键词：imaging Fourier transform spectrometer;SNR （signalnoiseratio）
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发布时间：2021-06-10 - 摘要：The change detection is one of the important topics in multitemporal remotely sensed data. The present paper introduces a method for multivariate change detection, which is based on the canonical correlation analysis and the orthogonal transformation. Moreover, an experiment with NOAA/AVHRR data is presented.\;Differing from traditional multivariate change detection schemes such as the principal component analysis （PCA）, this method takes two multivariate or multispectral satellite images as a whole set; each image set （of both） covers the same geographic locations and is typically acquired at different times. Then the twodate image sets are transformed into one set of new random multivariate by using the canonical transformation. By doing so the correlation between the spectral bands in the same image and in the twodate images are removed so that the actual changes in all bands can be simultaneously and accurately detected. This method has been tested for inundation detection of Poyang Lake of China during the summer 1998 flood along Chang Jiang. The results were very promising. The method has a great potential for automatic change detection by using the multisensor and multitemporal remotely sensed data.关键词：canonical correlation;canonical transformation;multivariate analysis;change detection;remote sensing imagery
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发布时间：2021-06-10 - 摘要：Remote Sensing Orthophotoquad （RSDOQ） has been widely used in the area of topographic map making and its revision, natural resource and environment surveying and monitoring, natural disaster mitigation and city planning etc.. However, for the generation of RSDOQ, DEM （Digital Elevation Model）is still needed to solve the issues of relief displacement for high resolution image （such as SPOT and IRS）. According to the characteristics of aerial image and space remote sensing image, and the difference among topographic relief, this paper proposed and developed new methods of RSDOQ generation without using DEM. The presented methods include integrated geometric rectification in flat area, locally adaptive geometric rectification in medium relief area, and point to point geometric rectification in high relief area. Only DRG （Digital Raster Graphics）, the scanned topographic man after geometric correction, is needed in our developed methods. Practical software has been developed and it will be used for the generation of digital orthophoto model （DOD） from remote sensing image in China.关键词：remote sensing images;Orthophoto model;rectification;fusion;registration
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发布时间：2021-06-10 - 摘要：An automatic approach of image registration is developed to register the multitemporal images of different sensors. A point in the coastline derived from SeaWiFS and AVHRR images is taken as a ground control point （GCP）, and the correlationrelaxation （CR） technique is employed to search the counterpart point of GCP. The correction of GCP values is guaranteed by a decision rule, which will improve the accuracy of registration. The relationship between the n th order bivariate transforms and the accuracy of registration is studied. The averages of RMS show that the larger number of GCP will lead to the more accurate image registration, while the high order bivariate transforms can not reduce that RMS of two images. The large number of GCP obtained by this method give a chance to study new transforms for geometric rectification to improve the accuracy of image registration. The approach described in the paper can be used in dynamic monitoring and integrating of Satellite data.关键词：image registration;satellite images;GCP;correlationrelaxation
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发布时间：2021-06-10 - 摘要：SAR images are subject to speckle effects which considerably reduce the detection of useful details within the scenes. Based on the analysis of the local speckle statistic characteristics of SAR image （such as relative standard deviation C u ） and algorithms of spatial filtering, an adaptive speckle filtering method is presented in this paper. Firstly, the special pixel neighborhood model is used in the selection of filtering windows, with which the filtering window is divided into 8 mutually exclusive sub windows and the central pixel is the only repetitions pixel in each sub window. Then, for every window to be filtered, the local relative standard deviation C i is calculated in all sub windows and used as the criteria to select the sub windows with C i<C u . Those selected sub windows are merged as a filtering area. Finally, recalculating relative standard deviation C x within the filtering area and different filter was used according to the difference of C x . In none of sub windows was selected or C x is larger than a threshold, the size of window should be reduced. If the size of window is 3 by 3 pixels, the central pixel should be replaced with the average of the nearest four pixels around it. The method was applied to both singlelook and multi look ERS 1/2 SAR images. The results show that the presented approach has the advantages both in speckle filtering and the preservation of image details.关键词：SAR;speckle;adaptive filtering;relative standard deviation;effective number of looks
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发布时间：2021-06-10 - 摘要：Due to the similarity of backscattering intensity of rocks, the general SAR data is not easy to make lithological classification on the earth surface. Polarimetric Radar records Stokes of Scattering Matrix of backscattering waves, which increases the classification precision. But meanwhile, the data fusion coming from the coherence of different polarizations in the polarimetric data produces more error for lithological classification. This paper divides the rock’s backscattering into three parts: Single Scattering, Double Scattering, and Cross Scattering The decomposition decreases the coherence of co polarization backscattering waves, enhances the backscattering difference of rocks, and shows the ability of lithological classification for polarimetric data. The polarimetric data used in this paper was obtained in October 1993, in the north of Xinjiang Province. With the statistic analysis, this paper builds the scatter plots for each kind of rocks, and input them into the Neural Network Classifier. The maximum precision is 94% and minimum error 1.06%.关键词：polarimetric SAR;target decomposition;lithological classification;scatter plot
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发布时间：2021-06-10 - 摘要：This paper studies the urban environment using remote sensing data with high spatial resolution airphotos and hyperspectral data. By using the ample spatial structural information contained in the high spatial resolution data and the fine spectral information contained in the hyperspectral data, a classification method based on edge detection and spectral analysis of the image was explored to classify the urban cover types on the per block bases. The result indicates that this method is effective for the study of whole urban environment.关键词：urban;edge detection;spectral analysis;classification
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发布时间：2021-06-10 - 摘要：The correlative relationship in the reflectance spectra, first derivative spectra of canopies and the chlorophyll content of early\|planted rice, late\|planted rice, and maize has been discussed. It shows that their correlative relationship is good, especially for the first derivative spectral data at the waveband 762 nm. Therefore, the same regression equation can be calculated for different crops. The linear regression equation has been built by using the first derivative spectral data of a part of samples at waveband 762 nm to estimate the chlorophyll content. Through the test of the other part of samples, it shows that the standard error is 0.272g/m\+2, and the estimated accuracy is about 80%.关键词：hyperspectral reflectance;chlorophyll content;derivative spectra
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发布时间：2021-06-10 - 摘要：Soil is an important resource on the Earth which provides materials and foods to people live on. The force and effects of the soil quality and quantity, both better and worse, touch the lives of local people. So the soil is too precious to be eroded away without trying to hold it in place and increase its productivity. The middle reaches of Ayeyarwaddy in Myanmar, is the most well known arid zone. The soil erosion and land retrogression are endangering the people’s lives. In this paper, we put forward a way of studying soil erosion and relations of soil erosion factors by integrated GIS and RS. Firstly, satellite images （TM and SPOT） have been integrated and the ground real conditions have been rectified. Secondly, according to the ecological environmental factors, the spatial database and Digital Elevation Model of the study area have been built. Finally, referring to National Universal Soil Loss Equation, the quantitation and distribution of the soil erosion, risks and changes have been obtained. By simulation and measuring, we study the relations in soil erosion and measurement, the relations in the soil erosion among forest type and crown, topography and the soil texture. Furthermore, we put on the rational spatial allocation of agriculture and forest. Thus, it is important and imperative to conserve the nature forest, close forest area, afforest in bare land, rationally utilize land and implement water and land conservation project as a way to control the soil erosion for ecological environment rehabilitation and the sustainable development.关键词：myanmar arid zone;Soil erosion;water and land conservation;environment rehabilitation
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发布时间：2021-06-10 - 摘要：Spatial Decision Support System （SDSS） is a new field developed on the basis of Geographic Information System （GIS） and Decision Support System （DSS）. Since the late 1980’s, more and more attention has been paid to the technology of SDSS in China as well as in the world. Through analyzing a large number of literature on the study of SDSS, it can be seen that presently people have many different understandings of SDSS. From authors’ point of view, only those systems which can provide decision makers spatial decision making schemes are deemed as SDSS and divided into three levels: general platform, domain tools and application systems. This paper will discuss the basic concepts and classification system of SDSS, architecture and operational modes of SDSS Platform （SDSSP）, and generation process of a SDSS application system, such as Spatial Decision support System for Agricultural Investment Planning in China （SDSS/AIPC）, supported by SDSSP.关键词：spatial decision support system （SDSS）;GIS;software platform;domain software tools;application system
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发布时间：2021-06-10
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