最新刊期
卷 17 ， 期 5 ， 2013
- 摘要：As one of the most splendid achievements in civilian earth observation history,the Landsat program has launched six successful satellites that have accomplished a 40-year mission of continuous earth observation.Owing to the program’s excellent technical characteristics,scientific data archiving and distribution strategy,Landsat data have been widely applied in ecological and environmental monitoring,natural resource surveys,college education and government management.The eighth generation of Landsat series,Landsat Data Continuity Mission（LDCM） satellite,is scheduled to launch in February 2013 with two sensor p ayloads,an Operational Land Imager（OLI）,and a Thermal Infrared Sensor（TIRS）.Compared with the previous ETM +,OLI and TIRS have advanced band specifications,radiometric performance and scanning systems.OLI collects image data for nine spectral bands with a new blue band for coastal environment monitoring and a shortwave infrared band for cirrus cloud detection.TIRS is designed with two thermal infrared bands.After a successful launch,LDCM（renamed as Landsat 8） will extend the Landsat data record and carry on the mission of earth observation.关键词：Landsat;ETM +;LDCM /Landsat 8;OLI;TIRS
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发布时间：2021-06-10 - 摘要：Up-to-date Soil Moisture and Ocean Salinity（SMOS） level 1C（L1C） Brightness Temperatures（TB）,which are p rocessed with the operational prototype V5.04 and V5.05,are used to analyze the systematic biases between averaged TB measurements and simulations in Fields of View（FOV） from May 2010 to April 2012.The peak-to-peak variations in the biases are higher than 1 K in magnitude.Sun contaminations,including sun alias and sun tails,are strong sources of bias variations in the FOV.The sun correction in the level 1（L1） image reconstruction is imperfect.By using the antenna model in L1,seasonal variations in the biases and the heating of the instrument are observed.关键词：brightness temperature biases;temporal variation;ocean surface;antenna temperature;sun correction
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发布时间：2021-06-10 - 摘要：The mapping of grassland biomass is of fundamental importance for estimating carbon budgets and the optimal use of grassland resources.The High Accuracy Surface Model for Grassland Biomass Simulation（HASM-GB） model was developed to estimate grassland aboveground biomass in Inner Mongolia,China.The ground truth biomass data and Normalized Difference V egetation Index（NDVI） were used to predict maximum growing season biomass maps using the HASM-GB model.To evaluate the performance of HASM-GB,it was compared with three other methods: Satellite-Based Regression Model（REG）,Ordinary Kriging（OK）,and Regression Kriging（RK）.As expected from theory,HASM-GB generally performs better than REG,OK,and RK,with a lower estimation bias,mean absolute error,root mean square error and higher correlation coefficient for measured and simulated values.From the predicted grassland biomass maps,the aspatial method vegetation index-biomass relationship technique was directly used with the variable NDVI to estimate biomass,and the precision of the results depend largely on how closely the primary and secondary variables are related.The spatial variation of the biomass produced by this method is very similar to the spatial variation of NDVI,so the simulation result is sensitive to errors in NDVI data.The OK method cannot factor information regarding vegetation index.However,HASM-GB can consider both the spatial structure of the measured biomass values and the NDVI data affecting local spatial trends,and it also had a higher precision of interpolation than RK.Consequently,HASM-GB is shown to be relatively effective for simulating spatial patterns of grassland biomass.关键词：high accuracy surface modeling;grassland aboveground biomass;spatial pattern;remote sensing;normalized difference vegetation index
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发布时间：2021-06-10 - 摘要：Moisture is one of the most important parameters affecting soil polarization spectra,and is critical to soil remote sensing band selection and image interpretation. It also provides information required for soil investigation and analysis of physical and chemical properties. In this paper,we tested and analyzed the polarization spectra of soils with different moisture contents in the wavelength range of 350 nm to 2500 nm to study the relationship between soil spectral polarization data and soil moisture,to determine the spectral response and changes in soil moisture,and to establish models of the relationship between spectral data and soil moisture. We also designed an orthogonal test for the various factors that affect soil spectral polarization characteristics,in which we studied soil moisture,polarization angle, detected angle,and azimuth of the various factors and their interactions. The results showed that the most significant factors were soil moisture and the interaction of soil moisture and polarization angle,followed by the interaction between the detected angle and moisture, while the polarization angle had little impact on the soil polarization spectra.关键词：polarization;spectrum;soil moisture;Model;interactions
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发布时间：2021-06-10 - 摘要：We present an in-depth study on the rigorous imaging model of high-resolution remote sensing satellites. After a brief analysis of the generally established method and process of developing the rigorous imaging model of a spaceborne linear array CCD sensor,three improved rigorous imaging models are proposed for the SPOT 5 HRS / HRG,ALOS PRISM,ZY-3 TLC,and other typical high-resolution remote sensing satellite sensors. We also propose the design of a model validation method based on the bundle block adjustment. The correctness of the rigorous imaging improvement models is verified using three types of satellite images and ancillary data over the Dengfeng remote sensing test field. Experimental results confirm that the three improvement i maging models are correct and applicable for effectively realizing geopositioning and block adjustment of the satellite images.关键词：spaceborne linear-array CCD sensor;rigorous imaging model;bundle block adjustment;ZY-3 satellite
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发布时间：2021-06-10 - 摘要：Faced with the problem of unstable reliability in matching long-strip imagery of Chinese satellite,a matching algorithm is presented using the global Shuttle Radar Topography Mission（ SRTM） data as elevation control. First,this algorithm employs the block partition mechanism,and introduces Local Binary Pattern / Contrast（ LBP / C） operator to filter the interest points. Second, the global SRTM data is used to compute the true topographic relief within the image coverage. Based on the true topographic relief, the approximate epipolar line is constructed and the accuracy is analyzed. Third,on the pyramid level,two-dimensional correlation matching is executed to search for the optimal matches along the epipolar line. During the matching process,the geometry rectification method is applied to improve the accuracy of matching. Finally,on the original level,Multi-Photo Geometrically Constrained（ MPGC） matching algorithm is adopted to refine the matching result,and Random Sample Consensus（ RANSAC） is imbedded to eliminate mismatches. In order to ensure the distribution uniformity of matches,the region-growing algorithm is introduced. The main advantage of the proposed algorithm is that it can realize the automatic matching for long-strip imagery of different Ground Sample Distance（ GSD）,different visual angles in parallel environment. Through the comparison between the proposed method and the mainly existing methods,the results show that the matching accuracy is improved.关键词：long-strip;SRTM;image matching;Mapping Satellite-1;ZY-3
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发布时间：2021-06-10 - 摘要：Image registration is used to detect changes in lakes by using large volumes of remotely sensed images. Alaska is c overed by ice,snow,and lakes all year,which make it difficult to find valid Ground Control Points（ GCPs） using remotely sensed images. This adds to the difficulty of image registration used in lake change detection and analysis. Based on lake change regulation,we propose that the deepest point of a lake is the most stable point during changes in the shape of that lake,and that this point can be used as a GCP in image registration. The center point of a polygon has been applied to many fields. Compared with the centroid of a polygon,the center point of the Largest Inner Circle（ LIC） of a polygon is always in the interior of the polygon,and the distance from this point to all the edges of the polygon remains the furthest,which meets the requirements of numerous applications. The center point of a polygon can be computed using the Voronoi diagram of the polygon. After analyzing the Voronoi d iagram computing procedure for a simple polygon,this paper presents the Voronoi method of generating a complex polygon,and then analyzes the algorithm complexity. We use the proposed algorithm to seek the LIC of many lakes in Alaska. Results show that the proposed algorithm can compute the center points of all the LICs of the lakes with high efficiency and achieve perfect registration effect based on these points.关键词：Voronoi diagram;center point of the largest inner circle;complex polygon;Alaska
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发布时间：2021-06-10 - 摘要：Buffer analysis is a very important spatial function of Geographic Information System（ GIS）. However,its efficiency in terms of time and space when used to process massive amounts of geographic data is very limited. To solve this problem,we define an approximate representation form—equational buffer which uses a mathematical equation to simulate the boundary of a buffer in GIS. Using equational buffer,buffer analysis is converted from a process composed of complicated geometric calculations to a process composed of simple algebraic calculations,leading to increased computational efficiency. This paper introduces the definition,pattern,application method and performance of the equational buffer. We also apply the equational buffer in the process of d ata filtering when estimating the real-time traffic information of China’s highways based on floating car data,and the experiment result validates that equational buffers are highly efficient in processing massive amounts of geographic data.关键词：buffer analysis;buffer representation;data filtering;equational buffer;large geographic dataset
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发布时间：2021-06-10 - 摘要：It is difficult to detect city cloverleaf,which is arised from shortcomings in traditional remote sensing image and the lack of appropriate methods. This paper presents an effective approach to extract city cloverleaf interchange footprints and boundary based on laser scanning data. We developed a plane-based approach to segment the data in the profile area and built a point o rganization structure called advanced scanline profile neighborhood system to identify the seed points. Alpha-shape algorithm was introduced to segment the seed points and generate the point sets boundaries. The cloverleaf interchange boundary was located by three-dimensional contour analysis based on model description. The complete cloverleaf footprints were determined by region-growing algorithm in the end,and meanwhile,the final cloverleaf boundary was obtained. The experiment was performed on the LiDAR data collected on a urban city. The result shows integrity and validly of our function that can get accurate length,width and morphology measurements comparing with the manual measurements from the high resolution ortho image.关键词：urban cloverleaf interchange;LiDAR;scanline profile neighborhood structure;Alpha-shape algorithm
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发布时间：2021-06-10 - 摘要：Normalized Difference Vegetation Index（ NDVI） time series data are widely used to detect vegetation changes,identify vegetation phenology,and classify land cover. However,original NDVI data contain a great amount of noise that results from o bserving conditions. Therefore,noise should be detected and removed in practical applications. Generally,methods to remove noise and reconstruct high-quality NDVI time series data sets can be grouped into three types: threshold detection,filter,and curve fitting. Each method presets a certain number of parameters according to different land cover types or a specific study area,resulting in a lack of objective criteria to define noise. These three methods do not include noise detection when reconstructing NDVI data; thus,noise is removed based only on experience. In this paper,a noise detection method based on Dixon’s test is presented. The proposed method is suitable for a small sample. Through this method,we analyzed the statistical characteristics of NDVI data from the same period of different years for a given pixel. The outlier in the NDVI time series was then determined based on quality assessment data. The noise detection method was applied to two existing data reconstruction methods（ i. e.,changing weight filter and Savitzky-Golay filter methods） to reconstruct the NDVI data over 520 test pixels of 55 vegetation types and a region in Dongting Lake in China from 2001 to 2010. Dixon’s test reduces the dependence on a priori knowledge for the data reconstruction methods, and data quality can be improved effectively through the proposed noise detection method.关键词：NDVI;noise;Dixon’s test;data reconstruction
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发布时间：2021-06-10 - 摘要：In this paper,we present an on-orbit geometric calibration method for a ZY-1 02C panchromatic camera in order to i mprove the geometric precision of its images. First,starting from a rigorous geometric imaging model,the source and character of geometric errors are analyzed,and on this basis,the on-orbit geometric calibration model is then set up. Second,the calibration p arameters are partially calculated with an iterative strategy by dividing them into two groups: external and internal calibration p arameters. Finally,base on the model and proposed method,an on-orbit geometric calibration experiment for a ZY-1 02C p anchromatic camera is conducted using the reference data of Songshan Calibration Test Site. The results indicate that the on-orbit geometric calibration model and method are feasible and have high accuracy and reliability,which can significantly improve the positioning accuracy of ZY-1 02C panchromatic images with and without ground control. Moreover,the precision of the internal calibration is better than 0. 3 pixels.关键词：ZY-1 02C panchromatic camera;rigorous geometric imaging model;on-orbit geometric calibration;external calibration parameter;internal calibration parameter;positioning accuracy
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发布时间：2021-06-10 - 摘要：This paper presents a"global-local"remote sensing information extract model,which extracts and integrates the spatial and spectral characteristics within the images’ local area. The model can optimize the accuracy of extraction on the pixels with spectral fuzzy. The model can be briefly described into two steps: "global"prior classifier and"local"posteriori classifier. The"global"priori classifier will only classify pixels which are above certain accuracy thresholds,and the "local"posteriori classifier will further explore the information of the already classified pixels from the partial-classified results. The local information will be used to classify the unclassified pixels at the global scale. When extraction of Impervious Surface Area（ ISA） experiment,we used Support Vector Machine（ SVM） as a priori classifier,which is controlled by an accuracy threshold to output the partial-classified results. We also used an Adjust Minimize Distance Classifier（ AMDC） as the posteriori classifier,which integrates the spatial information within local area around the unclassified pixels to classify the pixels with high degree of difficulty of classification by only spectral information. The experiment on the Landsat TM5 image and corresponding National Land Cover Database（ NLCD） pro-d ucts as reference indicates that"global-local"model enhanced the accuracy from 80. 31%,which is provided by SVM model,to 82. 73%. Meanwhile,the accuracy of posteriori classifier was enhanced from 54. 27%（ SVM） to 59. 94%. The results proved that combine with spatial and spectral information is an effective way for ISA extraction and the"globle-local"model can improve the accuracy of ISA extraction and can obtain more spatially explicit results.关键词：global-local;impervious surface area;remote sensing;information extraction
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发布时间：2021-06-10 - 摘要：The unreliability of communication systems may result in bit error or loss in the auxiliary data received by ground s tations from satellites. In such cases,it is impossible to obtain accurate geometric parameters by interpreting and calculating from auxiliary data,which will impede SAR imaging processing. To resolve the problem of deficient imaging parameters in spaceborne SAR imaging processing,this paper proposes a joint estimation scheme of imaging parameters based on SAR echo data. In this proposed scheme,the Doppler centroid and Doppler chirp rate are estimated using SAR data. The over-determined equations of both Doppler parameters and imaging geometrical parameters are then established,which take advantage of the Doppler properties of the spaceborne SAR. The Doppler parameter estimates are used to resolve the appropriate geometric parameter equations. Lastly,SAR imaging processing is accomplished by using the Doppler parameter estimates and geometric parameter estimates. Experimental results show that reliable estimates of both Doppler and geometric parameters are obtained using the proposed method,effectively solving the problem of deficient imaging parameters in spaceborne SAR image processing.关键词：spaceborne SAR imaging;Doppler centroid estimation;Doppler chirp rate estimation;over-determined equations;i nversion of imaging geometrical parameters
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发布时间：2021-06-10 - 摘要：We compute the total increase of the brightness temperature（ T） from each of the five layers in an FY-2E IR1 w indow imagery which corresponds to 50% and 30% increments in the aerosol extinction coefficient within a half hour p eriod. We used the MODTRAN radiative transfer model under the U. S. standard atmosphere,and analyzed the contributions to the total increment in aerosol extinction coefficient in spring,and the level at which the layered increment in T caused by an increment in the aerosol extinction coefficient is absolutely maximal compared with the T values of other l evels. We describe a time difference technique based on atmospheric radiative transfer theory,aim to extract the weak aerosol tracer from the FY-2E infrared（ IR） window channel with a sensitivity of 0. 2 K for clear sky conditions. Both the simulation and case studies results show that we can obtain atmospheric motion vectors（ AMVs） in the arid and semi-arid dust outbreak region by tracking the movement of a weak aerosol tracer in the FY-2E infrared（ IR） window channel using the time difference technique when traditional cloud tracking does not work due to the lack of clouds. The results are in good a greement with the 850 hPa wind field acquired in National Centers for Environmental P rediction（ NCEP） reanalysis data.关键词：radiative transfer;time difference method;AMVs in clear regions;FY-2E;aerosol
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发布时间：2021-06-10 - 摘要：Nitrogen dioxide（ NO 2）,sulfur dioxide（ SO 2）,and smoke are major pollutants from coal-fired power plants. In this study,we evaluated the air quality in coal-fired power plants by using satellite observations of NO 2,SO 2,and Aerosol Optical Depth（ AOD）. We first compared and analyzed the different temporal and spatial resolutions of NO 2,SO 2,and AOD in the North China Plain. Five classification grades were assigned to each pollutant factor,and then different images were overlaid based on the different weights of the pollutants. Next,the air quality model for near-surface evaluation was established. Multi-factors were s elected for a comprehensive evaluation to avoid the disadvantages of a single factor or function relation and to improve evaluation accuracy. Results show that the proposed model can reflect the characteristics of power plants in different regions.关键词：coal-fired power plants;SO 2;NO 2;Aerosol Optical Depth（AOD）;air quality
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发布时间：2021-06-10 - 摘要：Forest ecosystems,which are major parts of the terrestrial biosphere,play an important role in terrestrial carbon cycling and storage. However,the accuracy of forest carbon-flux estimation is greatly influenced by the lack of forest disturbance data. Thus, we conduct a study in Wuning County in Southern China by adopting a time-series trajectory analysis technique to detect forest disturbances in 14 Landsat Thematic Mapper / Enhanced Thematic Mapper Plus images from 1986 to 2011. This technique not only identifies forest disturbance,but also provides vegetation recovery information. By analyzing the time-space disturbance characteristics of forest disturbance,we found that Wuning County has suffered from a significantly dramatic disturbance in the 1990s,most of which has occurred in low-elevation areas because of human activities. Compared with field observations,the Kappa coefficient of our disturbance products reaches 0. 80 with an overall accuracy of 89. 7%,thus indicating the significant potential of the technique for forest disturbance monitoring.关键词：forest disturbance;Landsat data;time series
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发布时间：2021-06-10 - 摘要：Multi-functional Transport Satellite-2（ MTSAT-2） geostationary satellite data is used to monitor snow cover over China. Moderate Resolution Imaging Spectroradiometer（ MODIS） snow cover products and station observations are used for comparison and validation. Angular correction and multi-temporal data combination are carried out first based on MTSAT-2 data characteristics. Snow cover algorithm is developed based on different indexes and thresholds. MODIS snow cover products are used to compare with MTSAT-2 snow cover images from January 1 to 31,2011. Station observations are used for the accuracy e valuation. From this work,it can be found that:（ 1） cloud-contamination percentage of MTSAT-2 snow cover is about 30%,while 60% for MODIS snow cover products during the period of January;（ 2） under clear-sky condition,the overall accuracy of M TSAT-2 and MODIS snow cover both reach higher than 92%. Under all-sky condition,overall accuracy of MTSAT-2 and M ODIS is about 65% and 35%,respectively;（ 3） monitoring snow cover using MTSAT-2 data can remove more cloud and obtain more information about the surface. This method can be used in monitoring snow cover China with high accuracy,which is significant to climate change research and disaster prevention.关键词：MTSAT-2;geostationary satellite;snow cover
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发布时间：2021-06-10 - 摘要：Based on a quantitative study of the incident angle effect of a wide-swath synthetic aperture radar（ SAR） image,this paper proposes a class-based correction method for such an effect. The method achieves sampling by using watershed segmentation and regional labeling technology as well as a class-based radiation correction of land-cover backscatter values based on the cosine Lambert’s law estimated through linear regression. Experimental results of the Envisat Advanced SAR（ C-band horizontal-transmitting,horizontal-receiving polarization） data show that an incident angle effect is exerted on radar backscatter; the higher the moisture content of the land-cover type is,the more obvious the incident angle effect is. The correction of incident angle effect with this proposed algorithm is better than order cosine correction.关键词：incident angle effect;watershed;quantitative study;Lambert’s cosine law;linear regression
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发布时间：2021-06-10 - 摘要：The sunshine percentage is an important index in the radiation research and the solar energy assessment. Taking Jiangxi Province for example,we discussed the possibility to use the data from geostationary meteorological satellite to stimulate the s unshine hour distribution. First,we collected the cloud of FY-2C of 2007 and 87 meteorological stations sunshine hour data of Jiangxi Province. Second,we used multiple liner regression and weight coefficient methods to create two inversion models. Third,we a cquired 5 km × 5 km spatial resolution hourly percentage sunshine grid data of Jiangxi Province. By comparing the inversion results with observations data from 17 stations which were not involved in creating models,we found that the relative error and the Mean Absolute Error（ MAE） of the two estimation models is smaller than Inverse Distance Weighted（ IDW） and Kriging for more than 50%. The MAE and the relative error of multiple liners method were 3. 40% and 8. 62% smaller than weight coefficient method 3. 47% and 8. 75%. Both RMSE and error distributions were the same. The inversion data of both methods were bigger than the validation data except for the 17: 00 sunshine hour data. The MAE,RMSIE and relative error of 8: 00 and 17: 00 are much higher than the other hours. Results based on the comprehensive analysis show that geostationary meteorological satellite data based on the FY2C can be used in sunshine hour inversion,and the MAE of the two estimation models are much better than the traditional IDW and Kriging methods. According to data in 2007,the multiple liner model is better than weight coefficient model.关键词：FY-2C;cloud classification;sunshine percentage;estimating
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发布时间：2021-06-10 - 摘要：The Outgoing Long-wave Radiation（ OLR） derived from the FY-3A /VIRR and NOAA19 /AVHRR satellites indicated the presence of some errors. To satisfy the needs of the operational and scientific studies,it was necessary to analyze the similarity and differences in the FY-3A / VIRR-OLR and the OLR derived from other satellites. Using the daily average OLR of FY-3A / VIRR as the test data,the daily average OLR of NOAA18 / AVHRR as the test source data,and using the methods to determine the correlation coefficient,deviation,root mean square error（ RMSE）,and relative error,the similarity and differences of the daily average OLR of the satellites FY-3A / VIRR and NOAA18 / AVHRR were analyzed. The results showed that the correlation coefficient was large and the deviation,RMSE and relative error were small for the majority of the two sets of data. However,the correlation coefficient was small,and the deviation,RMSE and relative error were large for a small proportion of the two sets of data. For example,on April 23,July 13,and October 13,2010,the correlation coefficient was 0. 63,0. 5,and 0. 3,respectively; the deviation was 7 Wm- 2,-5 Wm- 2,and-200 Wm- 2,respectively; the RMSE was 31,45,and 225 Wm- 2,respectively; and the relative error was 0. 12,0. 125,and 0. 85,respectively. The difference occurred mainly in the mountains and the tropical oceans,and the difference was larger in the warm season than in the cold season. The difference in the two sets of data may have also been caused by the stronger convective flow in the mountains and tropical oceans in the warm season. Because the FY-3A Satellite acquired the data in the morning and the NOAA18 Satellite acquired the data in the afternoon,there were different orbiting periods,which may have led to differences for the two sets of data.关键词：FY-3A/VIRR;NOAA18 /AVHRR;Outgoing Long-wave Radiation（OLR）;difference
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发布时间：2021-06-10 - 摘要：<正>2013年7月2日至10日,北京大学成功主办了第十届"定量遥感"暑期研究生精品课程班。本届课程班先后邀请了多名国内外知名专家学者讲授定量遥感课程,其中包括童庆禧院士、郭华东院士、丁一汇院士、"千人计划"入选者李召良研究员与李军教授、科技部国家遥感中心总工程师李加洪研究
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发布时间：2021-06-10
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