最新刊期
卷 17 ， 期 3 ， 2013
- 摘要：Using full utilization of the high temporal and spatial resolution Environmental Satellite （ EnviSat） Advanced Synthetic Aperture Radar （ ASAR） data,we implemented a high-precision estimation of the annual calving area of Antarctic ice shelves,as well as an interpretation of the calving type. With EnviSat ASAR data which 40 times repeatedly covered the whole Antarctic coastline,we detected the location,type and occurrence time of iceberg calving events,and conducted statistical analysis on the temporal and spatial variation data with respect to the calving frequency and calving area of Antarctic ice shelves from August 2005 to August 2011. The results showed that （ 1） from 2005 to 2011,the mean annual calving area of Antarctica was 2969. 7 km 2 ,with a large varying amplitude of annual calving area and a slight decrease of the annual calving frequency; （ 2） the calving events of Antarctic ice shelves mainly occur from January to March,and most frequently in February; （ 3） the Wilkes Land located in East Antarctica is currently the area where iceberg calving occurs most frequently. The three major ice shelves,Ross,Filchner-Ronne and Amery ice shelf,are stable and calving events are rare. Ice shelves in the Queen Maud Land located in East Antarctica is relatively stable; （ 4） the frequency of iceberg calving with special scale less than 100 km 2 accounts for 94. 1% of total frequency,and ignoring them will lead to an underestimation of the annual calving area of Antarctic ice shelves by 20. 7% to 92. 9% ; （ 5） the rift-opening calving （ R-calving ） whose main driving force is internal glacial stress is more frequent than the melt-related calving （ M-calving） whose main driving force is the external atmospheric and oceanic factors,but the difference is not that large （ about 10%） .关键词：Antarctica;ice shelf;iceberg calving;ENVISAT;ASAR
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发布时间：2021-06-10 - 摘要：Sea ice concentration is an important parameter for polar sea ice monitoring. Currently,the highest resolution micro-wave-detected sea ice concentration gridded product is provided by University of Bremen,which is derived by the Arctic Radiation and Turbulence Interaction Study （ ARTSIST） Sea Ice （ ASI） algorithm based on 89 GHz Advanced Microwave Scanning Radiometer for Earth Observing System （ AMSR-E） data. For the purpose of providing the first generation Chinese sea ice remote sensing product for polar regions,we implemented a series of experiments including the interpolation algorithm,tie-points,and the weather filter based on the ASI algorithm for AMSR-E 89 GHz data. The main parameters,tie-points threshold value of pure ice （ P1 ） and pure water （ P0 ） of ASI algorithm in the Arctic region were statistically analyzed throughout year 2009. The results showed that the yearly average value of P1 was 10. 0 K,and that of P0 was 46. 67 K in the pure ice and pure water typical regions of Arctic. The retrieved values of ice concentration is sensitive to P1 and P0 when the differences of tie-points value are larger than 2 K. The effects of P1 and P0 on the ice concentration also changed for different P values. The calculation fomula was amended based on the statistic tie points. The sea ice concentration inversion fields in Arctic region of whole 2009 was o btained and compared with the products of University of Bremen. Furthermore,12 cloud-free samples were selected from the visible band of Moderate-resolution Imaging Spectroradiometer （ MODIS） image in Bering Sea and Chukchi Sea,and the derived sea ice concentration of MODIS data is averaged in the AMSR-E grid to validate the AMSR-E sea ice concentration. The comparisons of these samples showed that the error of our results is slightly less than that of University of Bremen’s product with the spatial average error and spatial average absolute error of 3. 84% and 10. 83% ,respectively.关键词：AMSR-E;ice concentrations;retrieval algorithm;validation;polar region
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发布时间：2021-06-10 - 摘要：The purpose of this research is to assess the accuracy of sea ice concentrations derived from AMSR-E data using ship observations from the 26 th Chinese National Antarctic Research Expedition （ CHINARE） and Landsat-7 ETM + Imagery in Antarctic. The comparison of AMSR-E sea ice concentrations with ship observational data indicated a general linear relationship between the two types of observations （ R2 = 0 . 816） ,but two types of data didn’t match each other quite well. AMSR-E tended to underestimate sea ice concentrations （ compared to ETM + ice concentrations） ,with average ice concentration biases ranging from - 5. 33% to - 21. 5% and corresponding Root Mean Square Errors （ RMSEs） ranging from 13. 7% to 33. 8% . For the Landsat-7 ETM + sea ice type classification,the l argest errors occurred in areas of new ice; in such areas,new ice was recognized as seawater by AMSR-E owing to its emission of passive microwave radiation,which is different to that emitted from other first-year ice.关键词：sea ice concentration;Landsat-7 ETM + imagery;ship observations;Antarctic
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发布时间：2021-06-10 - 摘要：The interannual variations of the Arctic total column ozone in springs from 1979 to 2011 are analyzed using measurements of the Total Ozone Unit （ TOU） onboard the second generation polar orbiting meteorological satellite of China,Fengyun-3 （ FY-3/TOU） and other satellite instruments. It is found that the interannual variations are very distinct and are connected with the stratospheric temperatures （ with a correlation coefficient of 0. 75） . The daily and monthly variability of Arctic ozone are very different in the anomalous years. The chemical impact is pronounced in the strongest ozone loss years （ 1997 and 2011） ,but not obvious in the weakest ozone loss years （ 1999 and 2010） . The daily variations in the weak ozone loss years could be regulated by weather system processes. The Arctic ozone variations are modulated by the atmospheric circulation,accounting for change of the Artic O scillation （ AO） ,polar vortex and stratospheric temperature. When the AO index is positive and the polar vortex is stronger with colder stratosphere,the Arctic ozone loss is larger. When AO index is negative and polar vortex is weaker with a warmer strato- sphere,the Arctic ozone loss is smaller.关键词：TOU;ozone;FY-3 satellite;polar vortex;circulation
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发布时间：2021-06-10 - 摘要：Surface albedo in the Arctic is one of the most important factors influencing the polar heat budget. The impact of variations of the Arctic sea ice albedo on the heat budget of the earth-atmosphere system and on global climate change is significant. I n this paper,the surface albedo in the Arctic was derived using the Level-1B （ L1B） data from the advanced very high resolution radiometer （ AVHRR） onboard the National Oceanic and Atmospheric Administration （ NOAA） polar-orbiting satellites. We applied narrow-to-broadband conversion,anisotropic correction,atmospheric correction,and cloud detection to the satellite data,and o btained broadband surface albedo products in clear conditions with a 4 km spatial resolution. Comparisons between the AVHRR albedo products and in situ measurements collected during the Surface Heat Budget of the Arctic Ocean （ SHEBA） project showed a bias of - 0. 07 and a standard deviation of 0. 05 during the spring-winter season. Monthly averaged NOAA / AVHRR surface albedo data from 2008 to 2010,combined with in situ measurements from the fourth Chinese Arctic research expedition,were used to study the variation of the Arctic sea ice albedo. The influence of snowfall and ice ridges on the variation of surface albedo was a nalyzed. The albedo decreased significantly and rapidly by about 0. 3 when the snow was melting. Comparing between the albedo variations in the rough multi-year ice area and smooth first-year ice area shows an albedo difference of 0. 2 during the melting s eason. The results indicate that the melting of snow and ice was the dominant factor for the variation of the Arctic albedo.关键词：NOAA /AVHRR;Arctic;albedo;snowfall;ice ridge
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发布时间：2021-06-10 - 摘要：This paper introduced several important issues on applying ground-based automatic sun-sky radiometer CE318 for aerosol remote sensing in Polar Region. Due to extremely low temperature and special weather condition like big wind in Polar R egion,scientists usually meet some particular problems when performing aerosol remote sensing based on direct sun and diffused sky light measurements. Following sun-sky radiometer CE318 measurements at polar region,this paper discussed （ 1） the importance and application of temperature correction to aerosol optical depth measurements in polar region; （ 2） temperature effects when performing instrument calibration in polar region using Langley plot method; （ 3） using diffused sky light in the retrieval of aerosol microphysical and optical properties to choose observation geometry. These studies can provide reference for performing ground-based aerosol remote sensing using automatic sun-sky radiometer in Polar Regions,and support satellite remote sensing of polar aerosol as well as assessment of its climate effects.关键词：polar region;aerosol;remote sensing;temperature correction;instrument calibration;Retrieval
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发布时间：2021-06-10 - 摘要：Remote sensing information products utilizing the multi-source,multi-scale,multi-temporal,multi-type remote sensing satellite data and ground observation data become important research topics. The various classification and gradation rules of data products from different remote sensing satellites in different countries have difficulty in meeting the requirements of the integration of multi-source and multi-type geographic information. The main products series as well as the classification and gradation rules for both domestic and abroad usage were investigated in this paper. A new classification and gradation rule for remote sensing s atellite data products in China was provided following the principles of efficiency,science,integrality compatibility,maneuverability,and extendibility. The classification rule was based on the spectral character and data acquisition method,whereas the g radation rule was based on the processing level of remote satellite data. The uniform classification and gradation rule was built. The rule could keep up with the correlative international standards that is still on progress. The rule included major remote sensing satellite data products at present and could conveniently build a mapping mechanism with other classification and gradation rules. Its scalability can meet the requirements of classification and gradation for new products in the future. The rule provided the basis for research on the indicator system of classification and gradation and for the development of correlative national standards.关键词：remote sensing satellite data products;classification;gradation;indicator system;standardization
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发布时间：2021-06-10 - 摘要：Doppler radar is capable of providing wind field information of precipitation echoes,and this makes it a powerful tool for the study of mesoscale weather processes. Assuming the change of radar reflectivity in a short time comply with the Lagrangian conservation,this paper proposes a new wind field retrieval method by which both radar reflectivity echoes and radial velocity data are used in the retrieval. Avoiding to assume the distribution of radial velocity in the retrieval,this method is theoretically applicable to all kinds of wind fields. This method is applied in two wind field simulation experiments,which use two temporally consecutive reflectivity echoes motions,and errors are generated. Error analysis shows that the retrieval results are more reliable when random error of the echo motion is less than 40% . Additionally,this method is used to analyze two mesoscale weather processes. The agreement between the wind retrieval results and the actual wind field structure proves the feasibility of this method in practice.关键词：Doppler radar;radial velocity;reflectivity factor;wind field retrieval;real weather processes retrieval analysis
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发布时间：2021-06-10 - 摘要：A new Moderate Resolution Imaging Spectroradiometer （ MODIS） and Landsat reflectance fusion method is proposed based on the Spatial and Temporal Adaptive Reflectance Fusion Model （ STARFM） and super-resolution reconstruction,which fuse observed MODIS and Landsat images to produce a Landsat synthetic reflectance image at the prediction date. Super-resolution r econstruction via sparse representation is first applied to enhance the resolution of a MODIS image. The results show that this o peration can enhance the spatial details of the original MODIS image and can improve the prediction accuracy of the STARFM algorithm. On the other hand,considering the problem of"temporal smoothing"attributed to large differences between two input pairs of MODIS and Landsat images,this method adds a patch-based selection strategy to the original STARFM algorithm. This strategy constrains each prediction of STARFM to use only one pair of MODIS and Landsat images at a base date. The optimal prediction of each patch is then selected from two images,which are predicted by two input pairs of MODIS and Landsat images. The results show that the proposed method outperforms the original STARFM algorithm in terms of prediction accuracy.关键词：data fusion;STARFM;super-resolution reconstruction;high-spatial and high-temporal resolution;Landsat;MODIS
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发布时间：2021-06-10 - 摘要：In the present study,an improved weighted iterative spectral mixture cycle called WLSMA is proposed based on the spectral unmixing method. First,this method divides the hyperspectral image into many regions and from each subregion endmembers are extracted automatically. Second,the extracted endmembers are clustered to distinguish different endmember classes from the overall type of spectra. We select the most representative endmember spectra from each class within the clustered results and process the optimal spectra using window convolution to establish an endmember spectrum sample library based on In-CoB. Third, an iterative spectral mixture cycle is applied to the image by introducing the compensation weighting matrix into the abundance e stimation. The results of the AVIRIS data set indicate that WLSMA,which combines Fisher’s principle and iterative spectral m ixture theory,increases the separability between similar minerals without a large amount of prior information,and offers greater flexibility and the possibility to improve the understanding and modeling of real-world data.关键词：hyperspectral remote sensing;weight spectral unmixing;Fisher principal analysis;iterative spectral mixture cycle;mineral mapping
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发布时间：2021-06-10 - 摘要：An improved method for Persistent Scatterer （ PS） detection was presented in this paper. Based on the time series of SAR amplitude data,the PS Candidates （ PSCs） were first selected using both amplitude threshold and amplitude dispersion index threshold. The true PSs were then screened out from the PS Candidate （ PSC） set by an iterative process based on phase stability a nalysis. The deformation values of the true PSs were finally estimated. The experiments of PS detection and deformation extraction were performed using 16 high resolution SAR images collected by the X-band radar sensor onboard the German satellite T erraSAR-X covering Shanghai. The test results demonstrated that the PS points detected by the improved method were more accurate and reliable than those identified by traditional methods. The maximum subsidence rate in the investigated area reached - 51 mm / a and the average subsidence rate was - 15. 8 mm / a. The subsidence rate error derived by PSI was ± 4. 45 mm / a compared with ground-based measurements derived by precise leveling. This confirms that the PSI technique is reliable for extracting regional ground subsidence using the proposed method.关键词：persistent scatterer detection;amplitude;amplitude dispersion index;spatial correlation of interferogram phase;d eformation
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发布时间：2021-06-10 - 摘要：Aimed at various kinds of original gaps on zoned heterogeneous spatial data in distributed environment,this paper p roposes a three-relational matrix （ 3RM） model. The model is divided into two phases. The first phase partitions the spatial computed unit using mapping rule or unified code and clusters the features of the zoned heterogeneous spatial data into groups. The s econd phase deals with the gaps in each spatial computed unit. The 3RM model focuses on the description and discrimination methods of the physical gaps on the zoned boundary. Based on the feature topology relation,attributive relation,and precision,the 3RM processing matrices are established. Meanwhile,38 kinds of potential gaps in the zoned boundary of the linear and regional spatial objects are discovered,and respective processing methods are put forward. Finally,the actual distributed and zoned heterogeneous land use data are used in the gap-processing experiment using the 3RM model. The result indicates that the 3RM gap-p rocessing model can deal effectively with various gaps in the actual zoned data and strongly support the seamless spatial analysis in distributed environment.关键词：zoned spatial data;distributed and heterogeneous;gap processing;seamless integration
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发布时间：2021-06-10 - 摘要：Snow-depth retrieval from passive microwave remote-sensing data has always been an active research area,though there are still several problems that need to be solved. Due to its concision and expansibility,the National Aeronautics and Space Administration （ NASA） algorithm has become the most widely used among the existing snow-depth retrieval algorithms. However,this algorithm still has its limitations: first,since it is based on linear fitting,the NASA algorithm needs to be re-fitted when we need to accurately measure snow depth greater than 1 m. Second,because the difference between the 19 GHz and 37 GHz brightness temperature measurements is completely saturated at different snow-depth ranges,the NASA algorithm will underestimate snow depth. In order to make improvements to these existing algorithms,the research in this article has attempted to develop a new algorithm of snow-depth retrieval based on the Ant Colony Optimization. Moreover,with respect to the underestimation of snow depth of the NASA algorithm,this article introduces 10. 7 GHz brightness temperature measurements taken by AMSR-E. Simulations from the Microwave Emission Model of Layered Snowpacks （ MEMLS） and the brightness temperature measurements of A MSR-E are applied to the snow-depth retrieval experiment. The retrieval accuracy of the algorithm is evaluated using the field-measured data and the AMSR-E Snow Water Equivalent （ SWE） product. Our results indicate that both of the algorithms produce accurate results,and the inversion results have improved to a certain extent compared to the AMSR-E product.关键词：snow depth;positive microwave remote sensing;ant colony optimization;NASA algorithm;AMSR-E
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发布时间：2021-06-10 - 摘要：The potential ancient graves in Northern Xinjiang of China almost appear into two types of circular marks: blob and ring marks with the faint boundary contrast on high resolution satellite imagery in Google Earth. In this paper,we proposed a circle detection method based on the local orientation using Genetic Algorithm （ GA） to extract them. Ours bases on the local orientation instead of the edge intensity,which was computed by the dominant component of the edge orientation histogram which is robust a gainst varying edge response. In our method,GA was used for robustness of circle detection against the shape disconnectedness, occlusions and other noises. We also used the geometric characteristic of the edge orientations at crossings of two circles to reduce the search space of GA for circle detection. The study was carried out on the unexcavated archaeological sites in the Northern X injiang of China. We compared our method to Hough Transform （ HT） method as the traditional robust circle detection. The r esults demonstrate that our method is much more robust against weak edge response and does not incur thresholds that are difficult to adjust automatically.关键词：ancient graves;soil marks;circle detection;edge orientation histogram;genetic algorithm
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发布时间：2021-06-10 - 摘要：This paper presents a method for the fusion of the airborne Light Detection and Ranging （ LiDAR） Canopy Height Model （ CHM） and the hyperspectral Compact Airborne Spectrographic Imager （ CASI） data （ CASI + CHM） to take advantage of vertical structural and spectral information as well as to evaluate the classification capacity of fusion data. Tree species in a natural temperate forest were successfully identified and compared with CASI data. Based on the vertical information obtained by using LiDAR, forest gap pixels were masked,whereas canopy pixels were acquired. In addition to the mean heights of tree species,training samples were extracted using the first derivative of a spectral curve with curve matching technology. Classification accuracies were compared between the fused data and data without CHM. The results show that the total accuracy and kappa coefficient （ 83. 88% ,0. 80） of CASI + CHM is better than those of CASI data alone （ 76. 71% ,0. 71） ,with the mapping accuracy and user accuracy of dominant species reaching a range of 78. 43% —89. 22% and 75. 15% —95. 65% ,respectively. These results are also better than those obtained through CASI data alone （ 68. 51% —84. 69% and 63. 34% —95. 45% ） . The proposed method for tree species i dentification in a natural temperate forest is feasible with fused LiDAR and hyperspectral data.关键词：LiDAR;hyperspectra;fusion;spectral derivative;support vector machine;classification of tree species
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发布时间：2021-06-10 - 摘要：<正>《遥感学报》创刊于1997年,是随着中国遥感事业的发展而成长起来的综合性学术期刊,也是目前中国遥感与数字地球领域的权威学术期刊。创刊以来,《遥感学报》结合中国遥感事业不同时期的重点和需要,刊登了大量国内最新科研成果和国家重点支持的研究项目的成果论文,对中国遥感科学技术的发展和人才培养发挥了巨大作用。该学报致力于报道遥感领域
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发布时间：2021-06-10 - 摘要：<正>2013-04-20 11:00中国四川省芦山县震区1:3000航空影像图1:3000 aerial image of Lushan earthquake on April 20,2013 in Sichuan China 2013年中国四川芦山"4·20"7.0级强烈地震发生后,中国科学院遥感与数字地球研究所立即启动了遥感应急响应预案。遥感飞机自4月20日9:50先后起飞4个架次,获取了震中周边50km范围,约5000km2,0.6m分辨率
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发布时间：2021-06-10
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