简介:TobuildarapidandaccuratemethodforgreenhousevegetablelandinformationextractionusinganindexmodelderivedfromTMdigitaldataofQingzhouCity,ShandongProvince,basedonasystematicanalysisofthespectralcharacteristicsofdifferentlandusetypesinthestudyarea,asubsetoftheimagewasfirstmadetoeliminatethemountainousregionnotassociatedwithvegetabledistribution,andthenwaterbodypixelsweremasked.WiththistheV1indexmodelforgreenhousevegetablelandextractionwasdeveloped.TheindexmodelindicatedgreenhousevegetablelandforQingzhouinApril2002wasconcentratedinthesoutheastandaroundruralresidentialareas.Fielddatausedforanaccuracyevaluationshowedthatgreenhousehectaresdeterminedwithremotesensingwere95.9%accurate,andaccuracyforthespatialdistributionofgreenhousevegetablelandcrosscheckedwitharandomsamplewas96.3%.Therefore,thisapproachprovidedaneffectivemethodforgreenhousevegetablelandinformationextractionandhaspotentialsignificanceformanagementofgreenhousevegetableproductioninthestudyarea,aswellasNorthChina.
简介:摘要:本文利用单窗算法对攀枝花市的三个区两个县进行地表温度的反演,并且对结果进行了统计分析,以此来研究攀枝花市的热岛效应。
简介:Inthisstudy,weusedLandsatimagesandmeteorologicaldatatoexaminethespatiotemporaldistributionandvariabilityofseaiceinJiaozhouBay(JZB)between1986and2016.TheresultsshowthatJZBisnotalwayscoveredbyseaiceinwinter,butinsomeextremecases,seaicehascoveredmorethanone-thirdoftheseaareaofthebay.SeaiceinJZBhasgenerallyformedbetweenJanuary1andFebruary5,primarilyalongthecoast,andgraduallyexpandingtothecentralareaofthebay.Bothmeteorologicalandartificialfactorshaveplayedimportantrolesinmodulatingtheseaicedistribution.Wefoundseaicecoveragetohavebeenstronglycorrelatedwiththeaccumulatedfreezing-degreedaysninedaysbeforetheoccurrenceofseaice(R2=0.767).North-northwestsurfacewindshavedominatedthefreezingperiodofseawaterintheJZB,andwindspeedhasexertedamoresignificantinfluenceontheformationofseaicewhentheseaicecoveragehasbeengenerallysmall.Additionally,artificialfactorsbegantoaffecttheexpansionofseaiceinJZBsince2007.TheconstructionoftheJiao-Zhou-BayBridge(JZBB)isbelievedtohaveretardedwaterflowandreducedthetidalprism,therebyleadingtotheformationofanicebridgealongtheJZBB,whicheffectivelypreventsthesouthwardexpansionofseaice.
简介:Moreaccurateestimationofcropevapotranspiration(ETc)inaregionalscalehasalwaysbeenoneofthemostimportantchallenges.TemporalandspatialmonitoringofETcusingsatelliteimagescanhelptoenhanceaccuracyofestimations.Inthisstudy,the(ETc)ricemapswereproducedbyusingstatistical/experimentalmethodsbasedoncropcoefficient(Kc)mapsderivedfromvegetationindex(VI).Kcwasestimatedusingfourmethods,includinglinearrelationshipbetweenKcandVI(Kc-VI),calibratedmodelofKc-VI,linearrelationshipbetweenKcb(thebasalcropcoefficient)andVI(Kcb-VI),andcalibratedmodelofKcb-VI.TheresultsshowedthatcalibratedmodelofKc-VIhadabetterperformancecomparedtotheothermethods,withnormalizedrootmeansquareerrors(NRMSE),meanabsoluteerrorandrootmeansquareerrorbeing5.7%,0.05mm/dand0.06mm/d,respectively.(ETc)ricemapswereproducedbyusingcalibratedmodelofKc-VIandreferenceevapotranspiration(ET0)fromFAOPenman-Monteithmethod.TheNRMSEwas21.3%forusingFAOPenman-Monteithmethod.Therefore,calibratedKc-VImodelincombiningwithET0basedontheLandsat7ETM+imagescouldbeprovidedagoodestimationof(ETc)riceinregionalscale,andcanbeappliedtoestimatewaterrequirementduetothefreeandfacilitateaccess.
简介:
简介:Weplantoestimateglobalnetprimaryproduction(NPP)ofvegetationusingtheAdvancedEarthObservingSatellite-Ⅱ(ADEOS-Ⅱ)GlobalImager(GLI)multi-spectraldata.WederiveanNPPestimationalgorithmfromgroundmeasurementdataontemperateplantsinJapan.Bythealgorithm,weestimateNPPusingavegetationindexbasedonpatterndecomposition(VIPD)fortheMongolianPlateau.TheVIPDisderivedfromLandsatETM+multi-spectraldata,andtheresultingNPPestimationiscomparedwithgrounddatameasuredinasemi-aridareaofMongolia.TheNPPestimationderivedfromsatelliteremotesensingdataagreeswiththegroundmeasurementdatawithintheerrorrangeof15%whenallabove-groundvegetationNPPiscalculatedfordifferentvegetationclassifications.
简介:WemappedtheforestcoverofKhadimnagarNationalPark(KNP)ofSylhetForestDivisionandestimatedforestchangeoveraperiodof22years(1988-2010)usingLandsatTMimagesandotherGISdata.SupervisedclassificationandNormalizedDifferenceVegetationIndex(NDVI)imageclassificationapproacheswereappliedtotheimagestoproducethreecoverclasses,viz.denseforest,mediumdenseforest,andbareland.Thechangemapwasproducedbydifferencingclassifiedimageriesof1988and2010asbeforeimageandafterimage,respectively,inERDASIMAGINE.Errormatrixandkappastatisticswereusedtoassesstheaccuracyoftheproducedmaps.Overallmapaccuraciesresultingfromsupervisedclassificationof1988and2010imagerieswere84.6%(Kappa0.75)and87.5%(Kappa0.80),respectively.Forestcoverstatisticsresultingfromsupervisedclassificationshowedthatdenseforestandbarelanddeclinedfrom526ha(67%)to417ha(59%)and105ha(13%)to8ha(1%),respectively,whereasmediumdenseforestincreasedfrom155ha(20%)to317ha(40%).ForestcoverchangestatisticsderivedfromNDVIclassificationshowedthatdenseforestdeclinedfrom525ha(67%)to421ha(54%)whilemediumdenseforestincreasedfrom253ha(32%)to356ha(45%).BothsupervisedandNDVIclassificationapproachesshowedsimilartrendsofforestchange,i.e.decreaseofdenseforestandincreaseofmediumdenseforest,whichindicatesdenseforesthasbeenconvertedtomediumdenseforest.Areaofbarelandwasunchanged.Illicitfelling,encroachment,andsettlementnearforestscausedthedenseforestdeclinewhileshortandlongrotationplantationsraisedinvariousyearscausedtheincreaseinareaofmediumdenseforest.ProtectivemeasuresshouldbeundertakentocheckfurtherdegradationofforestatKNP.
简介:以2013年08月11日马鞍山市Landsat8影像为数据源,利用ENVI软件反演了马鞍山市雨山区和花山区的地表亮度温度,再将地表亮度温度值归一化处理,划分为强绿岛区、绿岛区、正常区、热岛区和强热岛区5个等级.分析了马鞍山市热岛效应空间分布情况,并结合归一化植被指数(NDVI)和归一化裸地与建筑用地指数(NDBBI)与地表温度的相关性对马鞍山市热岛效应进行分析.结果表明:(1)马鞍山市热岛效应强的地区位于雨山区沿长江南北向延伸,城市建设用地的地表温度明显高于其他用地;(2)地表温度与NDVI呈负相关,与NDBBI呈正相关;(3)城市化、下垫面变化、工业生产等是造成马鞍山市城市热岛效应强烈的主要原因.
简介:利用Landsat系列影像提取水体的方法有很多种,细小的水体漏提或误提现象严重,依靠单一的方法难以取得突破。本研究结合现有的方法提出一种新的思路:1)基于DEM数据提取河网数据;2)辅以河网缓冲区数据将Landsat8影像的1-7波段和全色波段用于多尺度分割,根据形状特征提取线状的细小水体;3)假设2.5m分辨率影像提取的结果为实际水体,与基于像元的MNDWI法进行对比。结果表明水体的总体提取精度提高11.7%,细小水体提取比例从13.3%上升到59.6%,因此本方法简单易行,有利于线状的细小水体提取,可在一定程度上减少山区细小水体的漏提,提高水体提取整体精度。
简介:Background:Treelinedynamicshaveinevitableimpactsontheforesttreelinestructureandcomposition.ThepresentresearchsoughttoestimatetreelinemovementandstructuralshiftsinresponsetorecentwarminginCehennemdere,Turkey.Afterimplementinganatmosphericcorrection,thegeo-shiftingofimageswasperformedtomatchimagestogetherforaperpixeltrendanalysis.WedevelopedanewapproachbasedontheNDVI,LST(landsurfacetemperature)data,airtemperaturedata,andforeststandmapsfora43-yearperiod.Theforesttreelineborderwasmappedontheforeststandmapsfor1970,1992,2002,and2013toidentifyshiftsinthetreelinealtitudes,andthenprofilestatisticswerecalculatedforeachperiod.Twentysampleplots(10×10pixels)wereselectedtoestimatetheNDVIandLSTshiftsacrosstheforesttimberlineusingper-pixeltrendanalysisandnon-parametricSpearman’scorrelationanalysis.Inaddition,thespatialandtemporalshiftsintreelinetreespecieswerecomputedwithintheselectedplotsforfourtimeperiodsontheforeststandmapstodeterminethepioneertreespecies.Results:Astatisticallysignificantincreasingtrendinallclimatevariableswasobserved,withthehighestslopeinthemonthlyaveragemeanJulytemperature(tau=0.62,ρ<0.00).Theresultantforeststandmapsshowedageographicalexpansionofthetreelineinboththehighestaltitudes(22m–45m)andthelowestaltitudes(20m–105m)from1970to2013.TheperpixeltrendanalysisindicatedanincreasingtrendintheNDVIandLSTvalueswithintheselectedplots.Moreover,increasesintheLSTwerehighlycorrelatedwithincreasesintheNDVIbetween1984and2017(r=0.75,ρ<0.05).CedruslibaniandJuniperuscommunisapp.weretwopioneertreespeciesthatexpandedandgrewconsistentlyonopenlands,primarilyonrocksandsoil-coveredareas,from1970to2013.Conclusion:Thepresentstudyilustratedthatforesttreelinedynamicsandtreelinestructuralchangescanbedetectedusingtwodata
简介:Swidden农业是在山区的大陆东南亚洲(MMSEA)的一个古老、普遍却争论的耕作惯例。在北老挝的高地,swidden农业几个世纪仍然是一种占优势的人主导的陆地使用类型。然而,自从mid-1990s,swidden系统经历了戏剧的转变。在swidden耕作的变化上的争论被连接到全球性关键的问题,例如陆地使用/盖住变化(LUCC),生物多样性损失和环境降级。自从从采伐森林和福雷斯特降级(整顿)减少排出物的实现,许多注意在热带对swidden农业全国地并且国际性地被给予了。然而,swidden农业的明确地空间的特征和在宏观的规模的这些转变的后果的知识是令人惊讶地少见的。在这研究,在在1990,2002,和2011的北老挝的swidden使用和休闲森林恢复的紧张借助于Landsat题目的Mapper(TM)被描出并且提高了题目的Mapper加(ETM+)用一条决定树分类途径的形象(30m),在swidden农业由时间空间的变化的分析列在后面。下次,年度连续TM/ETM+图象在20002010期间被用来描出燃烧并且收割的阶段的动力学。随后,在2000识别的烧的象素在下列年(20012011)里与他们的对应物分别地被作比较用时间系列调查时间的趋势,陆地使用频率,和swidden周期基于Landsat的规范的差别植被索引(NDVI)数据。最后,当swidden周期从1~11年变化了,休闲植被恢复过程被学习。结果显示出那:(1)从1990~2011,swidden农业的区域增加了54.98%,从1.54?
简介:摘要江苏海岸进退给沿海港口生产和建设带来了直接影响。江苏海岸带的淤涨、侵蚀危及到江苏里下河地区和沿海垦区洪水入海通道和挡潮海堤的安全,同时也影响到沿海港口建设和社会经济发展。作者长期在沿海进行工作和调研,本文利用卫片对海岸带水陆分界线的位置变化进行研究。结果表明,江苏沿海40年来淤涨898.171km2,侵蚀635.725km2,1983年前后海岸变化有明显的差异。本研究致力于掌握滩涂岸线的变化趋势和发展规律,探明排涝体系的规划路径,为巩固海堤和港口建设提供基础资料。
简介:利用Landsat8遥感影像数据,快速提取道路、水体、植物和建设用地等反映湿地景观健康状况的景观要素,并生成评价指标,构建由指标优化函数和综合评定函数组成的湿地景观健康评价模型,实现对苏州市湿地的景观健康评价。评价结果表明,健康等级好和较好的湿地大多位于市郊,这些湿地开放水体面积相对较大,不易受到人类活动的干扰。单块湿地内部的健康状况也有较大差异,湿地内部中心区域的健康状况普遍要比外围区域好。利用遥感影像评价湿地景观健康状况,可以快速完成大面积湿地的景观健康评价,可以为湿地管理部门提供湿地健康评价的应用工具与决策依据,也可以为下一步重要湿地的精细尺度评价打下基础。