首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
STUDYONMODELFORREMOTESENSINGESTIMATIONOFMAIZEYIELDLiuZhaoli(刘兆礼)HuangTieqing(黄铁青)WanEnpu(万恩璞)ZhangYangzhen(张养贞)ChangchunInsti...  相似文献   

2.
Through analysis of perpendicular vegetation index (PVI) from combination of visible and near-infrared spectrums reflecting the feature of crop reflectance, we come to the conclusion that the index can better indicate crop instantaneous photosynthesis whereas people generally regard it as the representation of crop leaf area index (LAI). Exploration of crop photosynthesis within a day and its period of duration leads to production of photosynthetic vegetation index (PST) that can reflect the whole crop accumulated photosynthesis, which means the total biomass produced by crop, moreover the method simulating PST is put forward by employment of multi-temporal spectrum parameters. On the basis of the achievements mentioned above, a new comprehensive model for remote sensing estimation of maize yield is established, which can comprehensively show major physiological actions of maize and the course of its yield formation, organically integrate various effective ways of crop yield estimation. It lays a solid foundation for carrying out remote sensing estimation of maize yield on a large scale.  相似文献   

3.
“West Jilin Porovince” in ths paper means Zhenlai,Baicheng,Taonan,Da‘an,Tongyu,Fuyu,Songyuan,Qian‘an ,Chandling,also includes Gongzhuling,Shuangliao,Lishu,Siping and Nong′an which have been suf-fered from desertification.In west Jilin Province there are three sand zones passing through,they are Xiang(Xianghai)-Wu(Wlan Tug)sand zone,Hai-Fent sand zone,and Tao′er River right band sand zone.The desertification area of west Jilin Province is 819 100ha,making up 12.5% of the total land area.Among desertification types,in Jilin Province light desertification is the major,then is medium dersertification,hevey desertification is the least.According to the compare-son of the interpretation results of the Landsat images of the 1980s and 1990s by remote sensing and GIS techniques,it can be seen that the diesertification area in west Jilin Province basically didn′t change on the whole,only increased 6130ha,making up 0.8% of the desertification area,change scale is less than 1%.Evidently,desertification is con-trolled mostly,but some areas are continuing deterioration.The desertification process of China can be divided into three types according to origin nature,they are sandy steppe desertification,fixed sand area(sand land) activation and dunes transfer invasion.Reasons of desertification of West Jilin Province are analyzed,they include natural factors(such as material source factors,chimate factors) and artificial factors(such as destroying grass to reclaim,steppe decreasing greatly,illegally feeling shelter forest stands,constructing reservoir to influence eco-environment etc.).Some sugges-tions are put forward as follows:establishing the social project for ecological reconstruction of degenerated land;intensify-ing planning and management of land use,reverting farmland into forestland or pasture in a planned way.The key desertifica-tion control is to depend mainly on policy and management,then control techniques.  相似文献   

4.
1IN~IOXChinaisabigagriculturalcountrywithaverylargePOPulation.ChinesegovernmentattacheSgreatimportancetomdproduction.Anobviousapplicationofsatelliteremotesensing,withitsregularsynOPticcoverage,istOmonitoragriculturalpefforrnance.CropyieldestimationhaSbeenoneofthemainapplicationsofspaceremotesensingtechnologysincethelaunchingofhighrefutionsatellite-Landsat.Forgaininginformationofcropsproductionintime,StatePlanning~ssionsetupanationalkeyprojectduringtheeighthfiveyearplanPened(1991--1995)c…  相似文献   

5.
This paper attempts to explore a new avenue of urban small-regional population estimation by remote sensing technology, creatively and comprehensively for the first time using a residence count method, area (density)method and model method, incorporating the application experienqe of American scholars in the light of the state of our country. Firstly, the author proposes theoretical basis for population estimation by remote sensing, on the basis of analysing and evaluating the history and state quo of application of methods of population estimation by remote sens-ing. Secondly, two original types of mathematical models of population estimation are developed on the basis of remote sensing data, taking Tianjin City as an example. By both of the mathematical models the regional population may be estimated from remote sensing variable values with high accuracy. The number of the independent variables in the lat-ter model is somewhat smaller and the collection of remote sensing data is somewhat easier, but the deviation is a little larger. Finally, some viewpoints on the principled problems about the practical application of remote sensing to popu-lation estimation are out forward.  相似文献   

6.
Surface roughness parameter is an important factor and obstacle for retrieving soil moisture in passive microwave remote sensing.Two statistical parameters,root mean square (RMS) height (s) and correlation length (l),are designed for describing the roughness of a randomly rough surface.The roughness parameter measured by traditional way is independence of frequency,soil moisture and soil heterogeneity and just the ″geometric″ roughness of random surface.This ″geometric″ roughness can not fully explain the scattered thermal radiation by the earth's surface.The relationship between ″geometric″ roughness and integrated roughness (contain both ″geometric″ roughness and ″dielectric″ roughness) is linked by empirical coefficient.In view of this problem,this paper presents a method for estimating integrated surface roughness from radiometer sampling data at different frequencies,which mainly based on the flourier relationship between power spectral density distribution and spatial autocorrelation function.We can obtain integrated surface roughness at different frequencies by this method.Besides "geometric" roughness,this integrated surface roughness not only contains "dielectric" roughness but also includes frequency dependence.Combined with Q/H model the polarization coupling coefficient can also be obtained for both H and V polarization.Meanwhile,the simulated numerical results show that radiometer with a sensitivity of 0.1 K can distinguish the different surface roughness and the change of roughness with frequency for the same rough surface.This confirms the feasibility of radiometer sampling method for estimating the surface roughness theoretically.This method overcomes the problem of ″dielectric″ roughness measurement to some extent and can achieve the integrated surface roughness within a microwave pixel which can serve soil moisture inversion better than the ″geometric″ roughness.  相似文献   

7.
The crop estimates by remote sensing, developing quickly in recent decades, is a up-to-date technique. Regionalization for large area crop estimates by remote sensing, a special applied regionalization, is the foundation of crop estimates in a large area by remote sensing. According to the actual demands of wheat yield estimation by remote sensing and wheat agroclimatic demarcation of China, this paper first puts forward some principles upheld in this regionalization and analyses its main bases. Secondly, it works out the classificatory schemes about the optimum temporal for estimating wheat yield by remote sensing, information sources of space remote sensing and landuse structure in China. Finally, According to the regionalization indices, this study divides the wheat plantable region of China into 14 regions of crop yield estimates and 31 subregions of crop yield estimates.  相似文献   

8.
Advances in Research on Soil Moisture by Microwave Remote Sensing in China   总被引:2,自引:0,他引:2  
Soil moisture is an important factor in global hydrologic circulation and plays a significant role in the research of hydrology, climatology, and agriculture. Microwave remote sensing is less limited by climate and time, and can measure in large scale. With these characteristics, this technique becomes an effective tool to measure soil moisture. Since the 1980s, Chinese researchers have investigated the soil moisture using microwave instruments. The active re- mote sensors are characteristic of high spatial resolution, thus with launch of a series of satellites, active microwave remote sensing of soil moisture will be emphasized. The passive microwave remote sensing of soil moisture has a long research history, and its retrieval algorithms were developed well, so it is an important tool to retrieve large scale moisture information from satellite data in the future.  相似文献   

9.
Land-cover survey in northeast China using remote sensing and GIS   总被引:1,自引:0,他引:1  
I.INTRODUCTIONWiththerapiddevelopmentofnationaleconomyandthegrowthofthepopulationsincethe1990s,therecomesnewdemandsforexploit...  相似文献   

10.
In view of the large quantities of areas,complex landform and dynamic change of resources and environ-ment in China,China has already funded abundantly a series of macro remote sensing investigation projects in land use cover change(LUCC) since 1990.Supported by the achievements of such projects,Chinese resources,environmental and remote sensing database(CRERS) was created.In this paper,we standardized the LUCC dataset of CRERS at scale of 1km,which facilitated the study of spatial features of LUCC in China.The analysis on the spatial features of LUCC and their causes of formation in China are based on the CRERS supported by the technologies of Geographic Information System(GIS) .The whole research was based on the grade index of land use,ecological environmental index and index of population density.Based on the correlation analysis,we found that the special features of LUCC were closely related with those of ecological environment and population density,which resulted form that areas with better ecological environ-ment and high production potential of land were easy and convenient for human being to live,which,furthermore,led to the aggravation of excessive exploitation of land resources there.  相似文献   

11.
1 INTRODUCTIONAsanimportantcomponentoftheglobalterres trialecosystems ,forestlinkstheatmosphere ,soilandwatertogetherthroughitspowerfulecologicalfunc tion .Inrecentyears,owingtotheglobalwarmingandhumaninfluence ,forestfireoccurmuchmorefrequently .Theannualf…  相似文献   

12.
Geothermalanomalyisaphenomenonthatundergroundtemperatureandgeothermalgradientincreasesmuchmoreintheareathanitssurroundings(Xia,1979).Abruptgeothermalanomalymeansthatundergroundtemperatureonsomespotsaswellastheaffectedtemperatureofsurroundingareaabr…  相似文献   

13.
1INTRODUCTIONResearchonglobalenvironmentalchange,especiallyglobalvegetationchange,hasbeenmoreandmoreemphasizedbyscientistsandgovernments.HoWever,theinvestigationofvegetationcoveredinlargeareaneedagreatdealoffundandlaal.Asthesatelliteremotesensingdatahavebeenavailablesinceearly1980s,thesedataarebeingemployedtowardstOtheimprovementofvegetationclassification.NOAA--AVHRRdatahavebeenmoreandmoreusedbyscientistsbecauseOfitsshorttemPOralrefution,largescope,inexpensivecostandbreadwavebands.On…  相似文献   

14.
Based on the in situ optical measurements in the Bohai Sea of China, which belongs to a typical case-2 water area, we studied the characteristics of DCM (deep chlorophyll maximum) such as its spatial distribution, vertical profile, etc. We found that when the depth of the chlorophyll maximum is comparatively small, even in turbid coastal water regions, there is always a good correlation between the concentrations of chlorophyll maximum and the satellite-received signals in blue-green spectral bands; the correlation is even better than that between the surface chlorophyll concentrations and the satellite-received signals. The strong correlation existing even in turbid coastal water regions indicates that an ocean color model to retrieve the concentration of DCM can be constructed for coastal waters if a comprehensive knowledge of the vertical distribution of chlorophyll concentration in the Bohai Sea of China is available.  相似文献   

15.
LAND RESOURCES SURVEY BY REMOTE SENSING AND ANALYSIS OF LAND CARRYING CAPACITY FOR POPULATION IN TUMEN RIVER REGIONLANDRESOUR...  相似文献   

16.
本文以土库曼斯坦马雷绿洲为研究区,建立土地利用程度指数模型,利用2期遥感图像进行土地利用分类,对不同土地利用类型赋予相应属性;用正六边形网格采样,计算每个网格单元的土地利用程度综合指数;利用Kriging方法,对整个研究区进行土地利用程度综合指数插值和预测,分析马雷绿洲土地利用程度。结果表明:(1)研究区可利用土地利用类型主要为草地、耕地和撂荒地,占研究区的50%左右,呈减少态势;(2)研究区土地利用程度由中心向外围呈带状分布,土地利用程度综合指数等值线0.5为研究区绿洲与荒漠分界;(3)研究区中等及以上土地利用程度面积以年均0.079%递减,主绿洲与荒漠的面积比也由2001年的45.14∶54.86分别降为2010年的42.06∶57.94,说明研究区生态环境有恶化的趋势;(4)低、较高、高土地利用程度自身转移率均大于80%,而较低、中等土地利用程度自身转移率在50%左右。本文得到了马雷绿洲土地利用程度空间分布及变化,对研究区社会经济的发展及生态环境的保护具有指导意义,其技术流程和方法对今后的相关研究有一定的借鉴意义。  相似文献   

17.
UAV remote sensing images have the advantages of high spatial resolution, fast speed, strong realtime performance, and convenient operation, etc., and have become a recently developed, vital means of acquiring surface information. It is an important research task for precision agriculture to make full use of the spectrum, texture, color and other characteristic information of crops, especially the spatial arrangement and structure information of features, to explore effective methods for the cla...  相似文献   

18.
Volcanic eruption is one of the most serious geological disasters, however, a host of facts have proven that the Changbai Mountains volcano is a modem dormant one and has ever erupted disastrously. With the rapid development of remote sensing technology, space monitoring of volcanic activities has already become possible, particularly in the application of thermal infrared remote sensing. The paper, through the detailed analysis of geothermal anomaly factors such as heat radiation, heat conduction and convection, depicts the monitoring principles by which volcano activities would be monitored efficiently and effectively. Reasons for abrupt geothermal anomaly are mainly analyzed, and transmission mechanism of geothermal anomaly in the volcanic regions is explained. Also, a variety of noises disturbing the transmission of normal geothermal anomaly are presented. Finally, some clues are given based on discussing thermal infrared remote sensing monitoring mechanism toward the volcanic areas.  相似文献   

19.
By establishing the interpreting elements, and applying supervised classification, the sandy desertification was interpreted and the desertified land areas of the counties in the western Jilin Province in 1986 and in 2000 were obtained. Taking Tongyu and Qian‘an as examples, the natural driving forces and man-made driving forces were analyzed. The paper comes the conclusions that the material sources and the warming and dry climate are the internal causes of potential land descrtification: the irrational human activities, such as destroying forest and reclaiming the grassland, are the external causes of potential land desertification; while more rational human activities, such as planting trees and restoring grassland can reverse the land desertification. Furthermore, the countermeasures and suggestions for the development of agriculture and animal husbandry in the western Jilin Province are put forward.  相似文献   

20.
Remote sensing technique, replacing conventional sonar bathymetry technique, has become an effective complementary method of mapping submarine terrain where special conditions make the sonar technique difficult to be carried out. At the same time, as one kind of data set, multispectral remote sensing data has the disadvantage of being influenced by the variable bottom types in shallow seawater, when it is applied in bathymetry. This paper puts forward a new method to extract water depth information fi‘om multispectral data, considering the bottom classification and the true water depth accuracy. That is the Principal Component Analysis (PCA) technique based on the bottom classification. By the least square regression with significance, the experiment near Qingdao City has obtained more satisfactory bathymetry accuracy than that of the traditional single-band method, with the mean absolute error about 2.57m.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号