地球信息科学学报最新文献

{"title":"Indirect Measurement of Forest LAI to Deal with the Underestimation Problem Based on Beer-Lambert Law","authors":"H. Ronghai","doi":"10.3724/sp.j.1047.2012.00366","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00366","url":null,"abstract":"Leaf area index(LAI) defined as one half of the total green leaf area per unit ground surface area.It is an important parameter of canopy structure,because it relates to many biophysical and physiological processes of canopy,including photosynthesis,respiration,transpiration,carbon cycling,net primary productivity,precipitation interception,and energy exchange,etc.Accurate measurement of forest leaf area index by means of remote sensing has been an important task in remote sensing research.The direct method of LAI measurement is time-consuming,labor-intensive and may destroy plants.Compared to the direct method,indirect methods by means of optical methods are quicker and more efficient.These methods are all based on the Beer-Lambert law.As an important means to validate remote sensing LAI products,indirect LAI ground measurement is the basis and standard of remote sensing inversion.However,indirect ground measurement method based on Beer-Lambert law has serious underestimation problem in forest.The derivation of Beer's law was originally in uniform gas medium,when applied to discrete vegetation measurement on a pixel scale.Its applicability has not got enough attention and validation.In this paper,by theory analysis,we find that the underestimation of leaf area index comes from the spatial heterogeneity of foliage area volume density,extinction depth and leaf angle projection function G if Beer-Lambert law is applied to LAI measurements in forest.Quantitative assessment of impact on LAI measurement from non-random distribution of canopy was made.It was shown that non-random distribution of canopy may bring 20-40% measurement error of LAI.An important conclusion is that the simple correction of Beer-Lambert law has significant limitations on the in situ forest LAI measurement.This method is not a fundamental solution to this underestimation problem,and the theories and methods for LAI indirect measurement need to be changed.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69762584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring Spatio-Temporal Changes of Heat Island Effect in Beijing Based on HJ-1B","authors":"W. Liang","doi":"10.3724/sp.j.1047.2012.00474","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00474","url":null,"abstract":"The change of land surface temperature(LST)can reveal the heat environment of city,which leads to urban heat island(UHI).As a metropolis,Beijing has a serious urban heat island effect,so,analyzing and studying spatial and temporal changes of Beijing's urban heat island has a great significance.In this paper,we referenced image-based method to retrieve the land surface temperature using Environment Satellite image(HJ-1B) CCD/IRS as the main data source from 2008 to 2011,made preliminary validation on retrieval result using MODIS temperature products,then analyzed the annual and inter annual changes of urban heat island effect in Beijing.Further,we used thermal field variability index to make quantitative analyze of UHI.Finally,we analyzed the relationship among NDVI,NDBI and land use types.The results show that:(1) between 2008 and 2011,there is a significant heat island effect in Beijing.The heat island expanded from 2008 to 2010 but eased in 2011,the UHI were 5.2℃,5.2℃,9.2℃ and 8.2℃,respectively;(2) There is a significant heat island effect in four seasons of Beijing in 2010,the heat island in summer is the strongest,followed by spring and autumn,winter is the weakest,and the UHI were 8.2℃,9.4℃,9.2℃ and 4.3℃,respectively;(3) The quantitative distribution of UHI in Beijing from 2008 to 2011 showed that the UHI is mainly in urban,the heat island effect in the Southern of Fangshan District and Daxing District reduced year by year,the heat island effect of Changping District in 2011 is higher than in the previous three years,and vegetation and water formed urban cool island;(4) LST and NDVI are negatively correlated.LST and NDBI are positively correlated obviously,NDVI and NDBI have a significant impact on urban heat island,and urban heat island has a clear correction with land use types.So,increasing the city green area and water area can effectively slow down the heat island effect.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69762917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on Microwave Dielectric Properties of Different Salt Soils at L-Band","authors":"L. Baojiang","doi":"10.3724/sp.j.1047.2012.00376","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00376","url":null,"abstract":"Soil salinity caused by natural or human-induced processes is a severe environmental hazard all over the world.Approximately 955 M ha of soil have been affected by primary salinization worldwide,whereas secondary salinization affects approximately 77 M ha,with 58% of these in irrigated areas.This requires careful monitoring of soil salinity and mapping of the extent of salinized soils.Microwave remote sensing can significantly contribute to the detection of changes in salt-affected surface features.This paper describes a L-band resonant cavity technique at 1.43 GHz used to measure the complex dielectric constants of salt soils which contain NaCl,Na2SO4 and NaHCO3 respectively.The purpose of the new measurements is to evaluate the real components and imaginary components of dielectric constants as a function of water content,salinity and types of salts.The measurements on the dielectric properties of different salt soils show that the real components are strongly affected by soil moisture,for they increase with the increment of water content,whereas salinity has little influence on them,they tend toward constants.The imaginary components are not only dependent on water content and salinity but also on types of salts.Besides increasing with water content,the imaginary components of the three salt soils show different increasing trends with the increment of salt content.The value of imaginary component is e″ NaCIe″ NaHCO3e″ Na2SO4 under the condition of same saline concentration.Moreover,the slopes of the three salt soils vary with the change of water content that can distinguish the three salt soils.This study proves that L-band has a good sensitivity to soil salinity,and provides an experimental basis for the salt soil dielectric constant model building and future soil salinity monitoring using microwave remote sensing.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69762649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical Satellite Remote Sensing Capabilities Analysis of the Marine Oil Spill","authors":"Zhou Chenghu","doi":"10.3724/sp.j.1047.2012.00523","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00523","url":null,"abstract":"The marine oil spill impacts on the marine environment with the features of high frequency,wide range and great hazards.Using remote sensing for marine oil spill detection has become an important means.In this paper,we started with the spectral character of the marine oil spill,and established the relationship with the common optical satellite sensors.Then we analyzed the main physical parameters of the different optical satellites,including the spatial resolution,the time resolution,width and band number.The MODIS sensor and HJ-1 satellite has a strong monitoring capabilities of marine oil spill.Based on this,we used MODIS,BJ-1,HJ-1 and FY3 optical satellites images to monitor the marine oil spill accident occurred in the Bohai Sea in March 2006 and June 2011.The MODIS image can reflect the information of marine oil spill clearly in 2006 and 2011.The HJ-1 image can reflect the information of marine oil spill clearly in 2011,but the BJ-1 and FY-3 images cannot reflect the information of marine oil spill clearly in the two oil spill accidents.HJ-1,BJ-1and FY3 satellites in the band set are similar,but the BJ-1 and FY-3 satellites cannot reflect the information of marine oil spill.So in this article we compared the contrast of oil-water spectrum and the variance of the sea water spectrum using the MODIS remote sensing data.Experimental results show that,when the variance of the sea water spectrum is less than the contrast of oil-water spectrum in the MODIS band,the oil spill information can be shown on this band clearly.When the contrast of oil-water spectrum is less than or close to the variance of the sea water spectrum,the oil spill information cannot be shown on this band clearly.So through the above analysis,the MODIS sensor has a strong monitoring capacity on the spectral response of oil spill,spatial resolution,temporal resolution and the instance.This article has certain practical value of the optical satellite selected in marine oil spill remote sensing monitoring.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69762751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changing Characteristic of Land Surface Evapotranspiration and Soil Moisture in China during the Past 30 Years","authors":"Shao Quanqin","doi":"10.3724/sp.j.1047.2012.00001","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00001","url":null,"abstract":"The land surface evapotranspiration(ET) and soil moisture used in this paper were retrieved from land surface model(LSM) of NOAH.The variation of land surface ET and soil moisture was analyzed by statistics in six large regions and by four ecosystem types in China.Then the relationship between ET and soil moisture was discussed.The long term trend of land surface ET was increasing in China.The maximum ET occurred in July,while the minimum one was usually at the beginning/end of a year.The trend of ET in South-Central China,Southwest China,East China,Northeast China and Northwestern China was also increasing,agreed with the whole China.The long term variation trend of ET was decreasing in North China,where the maximum ET was 43.091 Billion Cubic Meters(BCM) in 1990.The relative ratio of evapotranspiration of forest was the highest among all the ecosystem types in Northeast,East,Southwest and South-Central China,while the highest one was grassland in North and Northwest China.To compare the amount of water used by evapotranspiration,the biggest forest ET was in Southwest and South Central China,the smallest was in Northwest China;the biggest grassland ET was in Southwest China,the smallest was in Northeast China;the biggest farmland ET was in East China,the smallest was in Northwest China;the biggest ET for desert and wet land was in Northwest and Northeast China respectively.The soil moisture was decreasing in most China regions except for that in Northwest China ever since 1980s,agreed with the whole China.The main impact factors of ET were vegetation fraction and soil moisture.There existed a good relationship between soil water content and evapotranspiration in rare vegetation covered regions.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis on Spatio-temporal Change and Driving Forces of Land Use in Tianjin Harbor","authors":"Fu Jingying","doi":"10.3724/sp.j.1047.2012.00270","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00270","url":null,"abstract":"In this paper,land use data of Tianjin harbor of four periods from 1987 to 2010 was obtained based on Landsat multispectral TM images.With the introduction of dynamic index of each land use type,dynamic index of land use change,conversion matrix and spatial pattern center of land use type,land use conversion in Tianjin harbor was analyzed quantitatively from the aspects of direction,extent,spatio-temporal differences and expansion pattern by support of GIS software.The results indicated that: from 1987 to 1995,Tianjin harbor was in the exploration stage after reform and opening-up with a low level of land use change;from 1995 to 2003,Tianjin harbor developed steadily while the construction land of port area expanded rapidly to the north;from 2003 to 2010,Tianjin harbor stepped into the specialization stage characterized by migration outside and land use type changed drastically during this period.For more than 20 years,Tianjin harbor presented an expansion pattern of along the coastline first to the north and land,then to the south and sea.Occupying of paddy fields and beaches,and sea reclamation are the main approaches of construction land expansion in Tianjin harbor.Meanwhile,extensive and irrational sea reclamation for land and aquaculture is prevalent in the study area.Research considered that port specialization development,national and regional policies and individual driving force were the principal factors that caused land use change of Tianjin harbor from the perspective of time and space.Harmonizing relationship between ecology,economy and regional development,optimizing port layout and promoting land use structure adjustment with the aim of ecological safety are the inevitable way to sustainable development.This article is of important significance in the full realization of port development pattern,the protection of precious port coastal resources,and the reasonable planning of land resources in port areas.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69762510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral Analysis of Different Degradation Level Alpine Meadows in 'Three-River Headwater' Region","authors":"Liu Jiyuan","doi":"10.3724/sp.j.1047.2012.00398","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00398","url":null,"abstract":"The 'Three-River Headwater' region at Qinghai Province is the source region of Yangtze River,Yellow River and Lancangjiang River.At here,grassland is the predominate ecosystem and alpine meadow is the main grassland type.In recent 30 years,large amount of grassland in this area suffered degradation,and therefore monitoring the alpine meadow degradation is important for grassland protection in the 'Three-River Headwater' region.The spectral characteristics of alpine meadow at different degradation levels are valuable information for alpine meadow classification and degradation monitoring through remote sensing.In this study,we measured the ground spectral data and surveyed grass samples in three sorts of alpine meadows at five degradation levels in August 2009 at the 'Three-River Headwaters' Region,Qinghai Province.Then we extracted and analyzed four characteristic values of the collected spectral data: the reflectance at 557675 and 760 nanometer and the red edge slopes.The result indicates that there are little differences among 557 nanometer's reflectance of the three sorts of alpine meadows at five degradation levels,but there are obvious differences among 675 nanometer's reflectance,760 nanometer's reflectance and the red edge slopes.We could distinguish the three sorts of alpine meadows at five degradation levels and make effective monitoring according to those differences.We also calculated the normalized differential vegetation index(NDVI) value of alpine meadow at five degradation levels based on their spectral data and related them with above ground biomass in this study.The result suggests that above ground biomass of alpine meadows at different degradation levels are well related to its 'red edge' slope and NDVI,with the determination coefficient of 0.93 and 0.87 respectively.Thus,these two parameters are useful for above ground biomass estimation based on remote sensing data.The 'red edge' slope of alpine meadows' reflectance not only could distinguish the three sorts of alpine meadows at five degradation levels effectively,but also has a better relationship with above ground biomass than NDVI value.Thus,'red edge' slope of alpine meadows' reflectance is essential for alpine meadows classification,degradation monitoring and biomass estimation.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69762978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Comparative Study of the Change Detection in Coastal Engineering Using BJ-1 Small Satellite Remote Sensing Data","authors":"Yang Xiaomei","doi":"10.3724/sp.j.1047.2012.00540","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00540","url":null,"abstract":"The coastal engineering exerts a great impact on the economic development and ecological environment of the seacoast.Thus,coastal engineering monitoring is a focus in coast zone remote sensing and monitoring.Since the 1980s,satellite remote sensing has become an indispensable technique in detecting the dynamic changes of coastal engineering.The accuracy of changes in coastal engineering is determined by the applicability of data obtained from remote sensing system and the feasibility of the methods in detecting the changes.As a satellite developed by China,the BJ-1 small satellite has already obtained numerous achievements in environment and disaster monitoring,urban management and construction and national land resource surveying.However,little has been investigated concerning the utilization of BJ-1 small satellite in monitoring the coast engineering.We compared various typical detection methods,and summarized a highly accurate and stable method in monitering the costal engineering with BJ-1 small satellite remote sensing data.Different detection methods were applied to investigate the changes in 2 key areas-Tianjin Port and Caofeidian Port costal engineering from 2006 to 2010 based on the characteristics of BJ-1 small satellite data,and evaluated the detected results.Our findings showed that among the detecting methods with BJ-1 remote sensing data,the maximum precision was obtained when waveband substitution technique was combined with SVM classification to detect the changes in costal engineering.The second precisest and stablest method was object-oriented analysis.These results indicate that,BJ-1 remote sensing data meet the requirements for accuracy in different costal engineering monitoring.Meanwhile,combination of waveband substitution and SVM classification technique,as well as object-oriented analysis,has the highest accuracy and stability in different costal engineering monitoring.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69763483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple Index Information Extraction of Marine Oil Spills","authors":"Cui Songxue","doi":"10.3724/sp.j.1047.2012.00265","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00265","url":null,"abstract":"The oil spills bring great damage to the marine ecological environment even taking decades to repair.Using remote sensing technologies for marine oil spill detection has become a major direction.In this paper,through analyzing the marine oil spill remote sensing detection methods,a new one based on the multivariate index of oil spill information extraction with the SAR data is proposed.First,segmenting the images,and then establishing the shape parameters,the texture feature indexes,and the physical indexes of the spots,the indexes weights were given based on the hierarchical analysis method.For each category index,on the image processing with the on-site validation information,select shape parameters,e.g.the perimeter-to-area ratio,complexity,to establish oil spill shape interpretive level.Choose the texture characteristics parameters from the gray level co-occurrence matrix,e.g.relevance,entropy and change,to establish the oil spill texture feature judgment level.Choose the physical characteristics,e.g.the standard deviation,RMS and contrast,to establish the oil spill physical parameters judgment level.Finally,by calculating the remote sensing information extraction index of the segmentations image dark spots,we can evaluate the credibility of the oil spill remote sensing information extraction,even get a significant basis for the oil spill identification.From the paper,oil spill in the SAR image performance mechanism,the image characteristics and the shape aspects can comprehensively reflect oil spill remote sensing detection characteristics,and the three combination confidence in the remote sensing monitoring has certain practical value.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69762492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on Forest Classification Based on Object Oriented Techniques","authors":"Wang Shikuan","doi":"10.3724/sp.j.1047.2012.00514","DOIUrl":"https://doi.org/10.3724/sp.j.1047.2012.00514","url":null,"abstract":"Since vegetation is an important indicator of global climate change,then the way to extract vegetation changing data should be put as the top priority.Especially,the extraction of sub-category information of forest vegetation has always been a difficult point in remote sensing image classification.And it is more difficult to extract sub-category information of the forest vegetation type only by taking advantage of the spectral information.As a widely-used method,object-oriented classification has been rapidly developed from the beginning of this century.Object-oriented classification method is mainly used in high-resolution remote sensing imagines,and it is applicable to medium resolution remote sensing images.This paper took Mentougou District,Beijing,which is mainly covered with forest vegetation,as the object of this research,and took HJ-1 image as the main data source then different buildings can be extracted by using the object-oriented classification method.By the reason of complicated terrain in this district,a hierarchical segmentation method was proposed in this research.Then different segmentation parameters could be set according to different buildings.Based on the spectral characteristic of the vegetation,appropriate characteristic parameters could be chosen and subordination function is constructed.After then,land cover types in this district could be extracted step by step and at the same time could be compared with those by the traditional maximum likelihood method.The result indicates that extraction accuracy of the forest vegetation sub-category data in this Mentougou District is 83% by using the object-oriented classification method.Compared with the traditional method,the extraction accuracy has been boosted a lot.","PeriodicalId":67025,"journal":{"name":"地球信息科学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69763193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}