最新刊期
卷 ， 期 3 ， 1993
- 摘要：This paper presents new ideas and recent progress in our joint effort to model the interaction mechanism of radiant flux with discontinuous canopies. At the scale of a small volume in which leaves can be regraded as homogeneously distributed, some recently develop-ped RT （Radiative Transfer） theories are the btst to model the phenomenon by using descriptors such as leaf scattering characteristics, leaf size, volume density of leaf area, etc. However, at the scale of a stand or TM pixel, GO （Geometric Optical） models catch the basic features of such stands under sunlight, i.e., foliage are clustered into crowns and crowns cast shadows. Hence in present practi ce, simple pure GO models are the only models which can be applied for natural discontinuous canopies.However, pure GO models require signatures of sunlit and shaded crown surface and background as known parameters under given situation or to be determined in situ. This has been proven a major restricting factor in applications and model inversion. And it is also a drawback that these signatures have not been related to leaf descriptors, wavelength, and sky conditions.In this paper, we proposed an integrated GO-RT approach to model the radiation climate in a discontinuous canopy. A key link in this approcah is gap probability （Pgap） model which we developped earlier. Gap probability, on one hand, can be obtained through pure GO model which reflects the structure at the stand scale. On the other hand, gap probability within crown is closely related to the pro cess that radiation collides and is scattered by foliage at the scale of RT models. Hence it becomes a natural link between two kinds of models best at the corresponding scales.In Li and Straheler （1988）, Pgap was modeled at the ground only. In this paper, the way to model Pgap at any height within canopies is developed. Vertical distributions of sunlit crown surface and within-crown pathlength distributions for different canopy structures are demonstrated. Since the penetration depth of direct sunlight into canopies play an important role in many fields other than remote sensing, we present here the results at this early stage of our modeling work to share with our colleagues in China for comments and possible validations. The way to model multiple scattering is also suggested in this paper. The concept of "Qpenness（Kopen） distribution" is introduced, and the （Kopen） at ground has been applied to shrub sites in HAPEX-Ⅱ-Sahel experiment and got good results. （Franklin et al. submitted to Agricultural and Forest Meteor., Feb., 1993）. The approach is still under development, though the initial results are encouraging.
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发布时间：2021-06-10 - 摘要：In recent yrars, We were engaged in the dynamic remote sensing monitoring of the projects in the sea areas of Macao and Modaomen. In this work, a problem rose: how to extract the remote sensing image information about underwater objects and structures. As well known, in the fields of resources environment remote sensing, water environment remote sensing is more complicated than land resources remote sensing mainly due to the small range of brightness of the water image pixel and the image is of low density with low pirel brightness. Therefore, the purpose of ocean image process ing is emphasizing and identifying the imforma-tion of underwater objects from water. It is even more technically difficult to extract the remote sensing information of offshore projects, which in pratice needs comprehensive multib-ranch knowledge. In this paper, an inf ormatio n extraction method combining, computer processing and optical processing with remarkable effectiveness is described. For an esample, according to the practical requirement of the projects in the sea areas of Macao and Modamen, successful verification of model flow pattern is provided by means of remote sensing image information. Dydamic image information about the barriers for the reclamaion project in the sea area of Modaomen is provided as well. Fruitful social and economic profit is achieved.
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发布时间：2021-06-10 - 摘要：The research is to explore the utility of multisensor remote sensing data to survey and map the tropical forest vegetation distribution.Those multisensor remote sensing materials are: （1） Spot-1 XS 16-Feb-1988; （2） Landsat-5 TM 02-Feb-1988; （3） Landsat-1 MSS 02-Mar-1973; （4） aerial panchromatic black and white photographs Mar-1989.The satellite remote sensing data were processed through histogram equalization, principal components analysis and maximum likelihood classification, by using a IIS model 75 with S-600 software, linked to a micro-VAX as host compu ter. The tropical forest vegetation classification system for surveying and mapping with remote sensing is developed.According to tropical forest vegetation classification system, the remote sensing images were interpreted before some field sampling of remote sensing images were conducted. The method of analysis that combined the image feacture with the forest ecological law was used in this interpretation. The details of interest for this research were forest vegetation type, so the boundaries delineated by tracing details on a transparency superimpsed on the spot XS or Landsat TM composites. But the satellite images can not be used for the classification of all forest vegetation types. This is he reason t hat aerial photographs of special sites were used in this research.After interpretation, all details of relevant forest vegetation types from satellite images were transferred to base map （scale 1:200,000 and 1:50,000） for making the forest vegetation map of xishuangbanna Prefecture and nature reserves. The Preliminary map accuracy is 38%, by some field verification. The forest vegetation maps was completed and printed.The research both provides the important basic data for protection and management of the tropical forest vegetation in Xishuangbanna and reveals that remote sensing technique especially multisensor remote sensing method is an economic and efficient technique for surveying and mapping the tropical forest vegetation.关键词：热带森林植被;多种传感器信息;图像处理;制图
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发布时间：2021-06-10 - 摘要：Various kinds of vegetation index have been proposed to minimize soil background influences based on the existence of "soil line" for forest monitoring and crop production prediction. They can only minimize soil moisture inf luen ces on remote sensing data along one axis, "soil line", which fail when different soil types appear （in the direction perpendicular to "soil line"）. A twoaxis soil-ajusted vegetation index is presented here to diminish most soil background influences, and it is more suitable as a global monitoring vegetation index than other index. TWVI model has been applied successful in rice production prediction in South China.
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发布时间：2021-06-10 - 摘要：In growing season, from planting to havest of crop is a complicated process. There are many factors that influence the final yield which is a comprehensive response of various factors, such as environmental conditions, biological factors and agricultural management and techni-gue etc. Thus, remote sensing information or meteorological data doee not reflects the conditions of crop growth actually. In this paper, an example in Shunyi County, Beijing, is given, and a winter wheat yield comprehensive model is proposed. The model is combined Perpendicular Vegetation Index （PVI） with meteorological data. A grey-system model G （0, 2） and successive corrected methods were used to establish a remote sensing- meteorological model for estimating winter wheat yield. By using multitemporal NOAA-AVHRR imageries and air temperature, the average accuracy of yield estimation is improved 7% in comprehensive model than in PVI model only.
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发布时间：2021-06-10 - 摘要：Urban Geographic Information System （UGIS） is a G1S branch with development rapid, application wide and benefit significant. The results, which got from the analysis of the applied tasks, thematic contents, technical requirements and system structure of UGIS and the comparison between the different models of software development, shows that: the development of UGIS software tools play a very important role in wide applications of UGIS in China. As one of UGIS software tools, the software structure, main functions and technical features of Geos-cience Remot sensing Application Management System （GRAMS） developed by the authors are presented. Moreover, through some UGIS applied systems, as samples, the different applied models of UGIS software tools and their benefits are described in the paper.
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发布时间：2021-06-10 - 摘要：On the basic microwave radiation theory o f three layered media, the effects of various media and environment parameters on the oil film thickness were analysed and calculated. The method of determining parameters was discussed. Jt was tested and verified with open pool experiments. In condition of obtaining two parameters of antenna brightness temperature at sea-water area and the oil film area with single microwave radiometer （8mm） of fix antenna, the model of calculating the oil film thickness of s outh China sea with airborne remote sensing was developed. The measured results over sea were closed with calculated values of the model.
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发布时间：2021-06-10 - 摘要：Manually digitizing maps for GIS is tedious, time consuming and imprecise. It has been a "bottleneck" in building GIS database. A new algorithm of combining the tracing and topological building to build the topological relationship directly from thinned raster data is proposed in the paper. It makes use of the topological information, that can be easily obtained in the processing of tracing to optimize the algorithm model of topological building, so the efficiency will be greatly improved. Lastly, a new thought of using the connected area fill method to deal with the complex island polygon is also presented in the paper.
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发布时间：2021-06-10
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