最新刊期
卷 ， 期 6 ， 2003
- 摘要：A key component of the surface energy balance over land is the albedo, defined as the ratio of the integrated total of reflected solar radiation to the integral of the incoming solar radiation. Climate is sensitive to albedo variation and its changes by natural variations and human activities. Predictions of climate change typically use a GCM linked to a land surface model. Land surface models, e. g. Biosphere Atmosphere Transfer Scheme（BATS）, estimate albedo of trees over snow roughly with the parameters of roughness length, Z 0, and snow depth, d . Based on their work, we further consider the difference in directional to hemisphere albedo for different solar zenith angle（ SZA ）, and leaf area index（ LAI ）dependence. In order to keep the basic feature of BATS model and add these two new features, we simplified geometric optical and radiative transfer（GORT）hybrid model to reach this purpose. In this paper, we take the conifer as an example. And we validate the model initially with observational data from MODIS and from BOREAS. Results show that: this model can simulate the observations well. This model can be rather simple to retrieve the albedo of remote sensing pixel. It can be a strong tool for understanding the climate system.关键词：GORT model;grid albedo;Directional gap probability;Openness
- 187
- |
- 347
- |
- 2
发布时间：2021-06-10 - 摘要：Starting with understanding the origin of the world,this paper points out a conceptual model of concrete and active theory object Point Resource System.Raw and compound Earth Observing Image Information（Remote Sensing GIS） is understood and processed according to the concept of Conformity Congregate Information Field and Discrete Object.Purposeful object information with definite boundary and position information is obtained by the size of the point source.What’s more,several application tools point resource vary scale model,point resource retrieval model and point resource earth surface characteristic model have been implemented to fulfill the extraction and process of mass data information until the procedure of info storage and info retrieve is formed.关键词：Point Resource System（PRS）;Conformitycongregate Information Field（CCIF）;Point Resource System Model（PRSM）
- 162
- |
- 140
- |
- 2
发布时间：2021-06-10 - 摘要：A methodology to build 3D urban visualization system is suggested,and optimized solutions to key problems are studied.Real estate data,cadastral data,and city planning data are the fundamental data.The data of buildings,roads,water system and topography are extracted,and they are used to build urban 3D visualization models.Texture data collected with digital camera are integrated with 3D building model to generate high resolution urban visualization data.Visualization procedures are developed with Visual C++6 0 and OpenGL to visualization the 3D data.With the help of this methodology,the 3D visualization system of Yangzhou Economic Development Region is constructed,and the efficiency of the methodology is proved.关键词：D urban visualization;GIS;digital city;optimize;3D model reconstruction
- 153
- |
- 186
- |
- 1
发布时间：2021-06-10 - 摘要：Through analysis of metadata standards from home and abroad,a metadata standard system for middle and small cities is suggested,it’s suitable for the building of fundamental urban GIS frameworks.The structure of the metadata database is designed,and a metadata system is developed with XML,so that the metadata can be managed and published.The metadata system has been successfully applied in building the fundamental GIS framework of Yangzhou Economic Development Region,and large volumes of spatial data has been seamlessly integrated to provide data service with the help of this system.关键词：metadata;XML;fundamental urban GIS framework;digital city
- 163
- |
- 456
- |
- 4
发布时间：2021-06-10 - 摘要：This paper describes another in flight method for satellite sensor absolute radiometric calibration, named irradiance based method which was used to calibrate the VIR channels of FY 1C with Dunhuang site. The inaccuracies of apparent reflectance computed by usual reflectance based method can be dependent on the aerosol scattering by assuming aerosol model. Irradiance based method substitute the measured ratio of diffusion to global irradiance to the aerosol scatter computed by radiance transfer code. Calibration results in five times show that the very good agreement with the reflectance based method for most dates confirm the validity of the irradiance based method. But the higher accuracy of the irradiance based method appears in the day when there is high aerosol.
- 197
- |
- 555
- |
- 21
发布时间：2021-06-10 - 摘要：Downward solar irradiance at the surface of the Earth is derived from the apparent satellite reflectance measurements from GMS 5 visible channel （0 4-1 1μm） based on a physical model of earth atmosphere system. The absorption and scattering of atmospheric molecule and aerosol on clear day are considered with standard mid latitude summer atmospheric model using the 6S, the scattering for other weather is abtained from the real time satellite albedo and the surface albedo acquired from the satellite measurements under clear sky condition. The effects of variations of aerosol and precipitable water on clear day to the surface solar irradiance are considered. Compared to the real time measurements by surface pyranometer, the correlation coefficient is as high as 95%, the deviation is about 10% of mean daily solar insolation. From the comparison, the accuracy of hourly solar irradiance estimated from GMS 5 in the text is improved.关键词：solar irradiance;GMS 5;observation;comparison;6S
- 154
- |
- 401
- |
- 10
发布时间：2021-06-10 - 摘要：As the key step of InSAR data processing, many phase unwrapping algorithms were introduced. But these algorithms had difficulties with high noisy interferogram. This paper introduced a new method based on netowrk flow algorithm in irregular network, out of regard for high interferometric coherence and neglecting low coherence data area. First, a new phase data set with high quality data is created. Delaunay triangulation network can be derived according to the positions of the high quality phases in the image and the residue of each triangulation in the network is calculated. According to the positions of the residues in the irregular network the flows are computed by the network flow algorithm, we can integrate along the flows and derive the unwrapped phases. Finally, we compare the unwrapped phase image computed by network flow method with the image by traditional path finding method. From the comparison, we can conclude that the network flow method can increase the accuracy of the phase unwrapping and decrease the error occured noise.关键词：Phase unwrapping;network flow algorithm;irregular network
- 211
- |
- 678
- |
- 9
发布时间：2021-06-10 - 摘要：In this paper, a new technique to solve the problem of bridge recognition from TM images is presented The algorithm takes advantage of the characteristics of TM images It uses morphology operators to collect candidate bridge objects in the segmented images; then chain code is used to represent these candidates and computer their parameters; and in the last step we recognize those true bridges according to some knowledge and make the result more rational by post processing The algorithm works fast and can work automatically, even though some man intervention can make it more robust The result is satisfying considering the low resolution of the TM images Results on the TM images of three different areas are given to demonstrate the efficiency of our method关键词：TM images;object recognition;morphology;chain code
- 176
- |
- 386
- |
- 14
发布时间：2021-06-10 - 摘要：For the traditional method of hyperplane segmentation, the location of hyperplane in data space was determined by statistical method. In the case of the statistical value of regions is smaller than thoes within the region, the statistical method was not effective. The character of genetic algorithm is global searching optimally. Taken this mathematical advantage, the location of Hyperplane could be located easily. In the paper, we use EOS/MODIS imagery data as an example to introduce this method in detail. We demonstrate that genetic algorithm can be used to produce segmentation result of remote sensing data. Using the parameters of the hyperplanes encoded in the chromosome, the region in which each training pattern point lies is determined by hyperplanes equation. Then the fitness is decided. After computing the fitness, the genetic operators of selection, crossover and mutation are applied to generate a new population of chromosomes. Then, after some process of this, the fitful hyperplane will be generated by this process. At last, the image was divided by the most fitful hyperplane equations. After the introduction of this method and its application, the comparative results with Maximum likelihood（ML）method in ERDAS IMAGINE 8.4 software package are given in section 4.As the paper shows, the genetic method is clearly better than ML method. It need to note that the realization is based on the Windows and Turbo c 2.0. We would have better results in VC++.based on Windows XP.关键词：genetic algorithm;remote sensing;hyperplane segmentation;location;EOS/MODIS data;classification accuracy
- 149
- |
- 220
- |
- 2
发布时间：2021-06-10 - 摘要：Aiming at the demand of Remote Sensing Investigation on Eco environment in Western China,this article synthetically utilizes the theory of Scenical Ecology,the theory of the service function of ecological system,the theory of the sustainable development and the technology of RS and GIS to study the process and integration of the RS data about eco environmental status in Western China.Based on that,the research staff develop the complex research about the constructional change of the landcover and eco elements in Western China,about the evaluation of the intensity of the desertification and water erosion,about the analysis of the ecological frail characteristic and temporal and spatial distribution law,about the evaluation of the eco environmental quality based on RS investigation and about the analysis of eco environmental RS in typical regions and the cause and countermeasure on the eco environmental change based on multi temporal RS data comparison.Furthermore,the author systematically reveals the law of the spatial distribution,spatial statistics and spatial characteristics in the form of quantitation.关键词：remote sensing;eco environmental investigation;western China
- 211
- |
- 1279
- |
- 8
发布时间：2021-06-10 - 摘要：By processing and analyzing space borne multi frequency microwave radiometry data acquired by SSM/I in different time, we aim at carrying out research on seasonal change of land cover characteristics in China. Through a short review on passive microwave remote sensing applications,we choose Normalized polarization index（ NDPI ） to describe land cover characteristics. Because NDPI is independent of surface temperature, it diminishes difference caused by acquiring time in data in various regions. It is also shown that NDPI is actually a normalized emissivity of different polarization. Its main influence factors are vegetation biomass and soil surface moisture. With biomass increasing, NDPI becomes smaller;with soil moisture increasing, NDPI increases also. Multi frequency SSM/I data acquired in April,July,October of 1997 and January of 1998（20 th and 24 th of every month ）were processed and analyzed. Then the SSM/I NDPI maps over land in China were put forward for the first time. These maps express seasonal change of land cover characteristics in China. By analyzing all of these data and maps, we found that specific land cover has specific NDPI value and NDPI value changes with season.It is concluded that the NDPI maps has great potential to monitor land cover characteristics. The general trend of NDPI is （from high to low）:desert, semi desert, plateau（grassland）, agricultural region and forest .The research illustrates that 19GHz NDPI is a good indicator of seasonal change of land cover characteristics. This paper also provides a new method to research on global change （such as vegetation and soil moisture change） because we have demonstrated in the paper that a NDPI map covering all of China can be formed by using only two day’s SSM/I data,and furthermore, this map is affected little by cloud and is independent of surface temperatrue.
- 221
- |
- 257
- |
- 8
发布时间：2021-06-10 - 摘要：The analysis of remote sensing indices to grasshopper outbreak is the base to develop the prediction model for grasshopper outbreak. A ratio based formulae for grasshopper outbread from Landsat 5 TM imagery, namely, RIG =（TM4+TM7）/TM6, was presented, according to the mechanism of remote sensing of grasshopper outbreak. The new algorithm（ RIG ） and two kinds of standard algorithms（the normalized difference vegetation index NDVI and the soil adjusted vegetation index SAVI ） were used to test significance levels for t tests of differences between mean Values of grasshopper site and non site respectively, combining with grasshopper outbreak information from field sampling in the region around Qinghai lake. The results showed that the RIG presented was superior to standard vegetation indices（ NDVI and SAVI ） used commonly at densities≥15 and≥25 grasshoppers/m 2; while inferior to NDVI and SAVI at densities≥5 grasshoppers/m 2. Therefore, the RIG is able to monitor grasshopper outbreak.关键词：remote sensing;grasshopper;in the region around Qinghai Lake
- 174
- |
- 348
- |
- 5
发布时间：2021-06-10 - 摘要：Human Earth System Science（HESS） is a new inter discipline between natural and social sciences to monitor, analyze, simulate, control and guide the behavior, evolution, distribution and effects of interaction systems between human and earth where they have lived and developed. The science and its applications to development of National Spatial Information Infrastructure（NSII） in China are separately presented in two parts of this pater. In the first part, as study achievements, a conceptual model, branch definition and an operational mode of HESS are introduced. The conceptual model describes the construction of the system and interactive relationships of its components. Four branches divided from HESS include regional, thematic, experimental and technical ones. The operational mode put the development and applications of the science into an iterative loop of decision making and routine activities. All of the achievements made to the development and applications of HESS have a solid theoretical basis and very bright future. In the second part, the ways to solve the problems of NSII development in China, guided by the theory of HESS as mentioned before, are demonstrated. The problems include objectives and application scopes, working boundaries, ways of data sharing and partnership formulation of NSII. Obviously, it is very significant for the development of NSII in China reasonably to deal with these kinds of problems.
- 134
- |
- 181
- |
- 1
发布时间：2021-06-10
- Postal code：100190
- Tel：010-58887052 Email：nrsb@aircas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备20021838号-9
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0