TechnicalEnglishForInformationScienceandElectronicEngineering0Unit15RemoteSensing1PartIAnOverviewofRemoteSensing2NewWordstether拴，束縛topographic地形的，地形學的novelty新奇，新鮮事物reconnaissance偵察oblique傾斜的perspective透視圖，透視的emergence出現Earth-orbiting繞地球軌道運轉的astronaut宇航員emit放射，射出categorize分類photon光子analogous類似的viceversa反之亦然accelerate加速descriptive描述性的ultraviolet紫外線，紫外的nanometer納米（10

9m）micrometer微米（10

6m）infrared紅外線，紅外的3NewWordsvapor汽，蒸汽ozone臭氧transparent透明的tune調諧line-of-sight視線radiant輻射的meteorological氣象的opaque不透明的impede妨礙，阻止vegetation植物decimal十進制的ingredient成分，因素informative提供消息的tint色彩discern辨別，看清楚radiometer輻射計quantitatively定量地imagingradiometer輻射成像儀spectrometer分光光度計grating光柵4NewWordsprism棱鏡spectroradiometer

分光光譜儀resolution分辨率trace痕跡、微量species種，類scatterometer

散射計lidar

激光雷達aerosol煙，霧constituent成分altimeter高度計51Thetechnologyofmodernremotesensingbeganwiththeinventionofthecameramorethan150yearsago.Althoughthefirst,ratherprimitivephotographsweretakenas“stills”ontheground,theideaandpracticeoflookingdownattheEarth’ssurfaceemergedinthe1840swhenpicturesweretakenfromcamerassecuredtotetheredballoonsforpurposesoftopographicmapping.19世紀40年代，為了繪制地形圖，當照相機被放在系留氣球上來拍攝照片，俯視地球表面的想法和實踐開始了61Perhapsthemostnovelplatformattheendofthe19thcenturyisthefamedpigeonfleetthatoperatedasanoveltyinEurope.ByWorldWarI,camerasmountedonairplanesprovidedaerialviewsoffairlylargesurfaceareasthatprovedinvaluableinmilitaryreconnaissance.Fromthenuntiltheearly1960s,theaerialphotographremainedthesinglestandardtoolfordepictingthesurfacefromaverticalorobliqueperspective.72Satelliteremotesensingcanbetracedtotheearlydaysofthespaceageandactuallybeganasadualapproachtoimagingsurfacesusingseveraltypesofsensorsfromspacecraft.Withtheemergenceofthespaceprograminthe1960s,Earth-orbitingastronautsactedmuchliketouristsbytakingphotosoutthewindowoftheirspacecraft.83Theterm“remotesensing”isnowcommonlyusedtodescribethescience,andart,ofidentifying,observing,andmeasuringanobjectwithoutcomingintodirectcontactwithit.Thisprocessinvolvesthedetectionandmeasurementofradiationofdifferentwavelengthsreflectedoremittedfromdistantobjects,bywhichtheobjectsmaybeidentifiedandcategorizedbyclass,substance,andspatialdistribution.1這一過程包含檢測和測量從遠處目標反射回來或發射出來的不同波長的輻射，由這些輻射，可按種類、物質、空間分布對目標進行識別和分類。94RadiationUnlessithasatemperatureofabsolutezero(

273

C)anobjectreflects,absorbs,andemitsenergyinauniqueway,andatalltimes.Thisenergy,calledelectromagnetic(EM)radiation,isemittedinwavesthatareabletotransmitenergyfromoneplacetoanother.104Forexample,trees,air,theSun,theEarth,andallthestarsandplanetsarereflectingandemittingawiderangeofelectromagneticwaves.Thesewavesoriginatefrombillionsofvibratingelectrons,atoms,andmolecules,whichemitandabsorbelectromagneticradiationinuniquecombinationsofwavelengths.2

這些波是由億萬個振動的電子、原子、分子發出的，它們以獨特的波長組合發出和吸收電磁輻射。114Theamountofelectromagneticradiationanobjectemitsdependsprimarilyonitstemperature.Thehigherthetemperatureofanobject,thefasteritselectronsvibrateandtheshorteritspeakwavelengthofemittedradiation.125ElectromagneticspectrumThefundamentalunitofelectromagneticphenomenaisthephoton,thesmallestpossibleamountofelectromagneticenergyofaparticularwavelength.Photons,whicharewithoutmass,moveatthespeedoflight–300,000km/secintheformofwavesanalogoustothewaywavespropagatethroughtheoceans.獨個光子能以波的形式運動，速度可達光速300,000km/sec，就像波浪在海洋中傳播一樣。135Theenergyofaphotondeterminesthefrequencyoflight.Thegreatertheenergyofthephoton,thegreaterthefrequencyoflight,andviceversa146TheentirearrayofelectromagneticwavescomprisestheEMspectrum.Thewavesarecalledelectromagneticbecausetheyconsistofcombinedelectricandmagneticwavesthatresultwhenachargedparticle(electron)accelerates.TheEMspectrumisdividedintoregionswithdescriptivenames.156Atthehighfrequencyendaregammaraysandx-rays.Radiationintheultravioletregionextendsfromabout1nanometertoabout0.36micrometers.Itisconvenienttomeasurethemid-regionsofthespectruminthesetwounits:micrometers(mm),aunitoflengthequivalenttoone-millionthofameter,ornanometers(nm),aunitoflengthequivalenttoone-billionthofameter.166Thevisibleregionoccupiestherangebetween0.4and0.7mm.Theinfrared(IR)regionspansbetween0.7and100mm.Atshorterwavelengths(near0.7mm)infraredradiationcanbedetectedbyspecialfilm,whileatlongerwavelengthsitisfeltasheat.177Longerwavelengthintervalsaremeasuredinunitsrangingfrommillimeters(mm)throughmeters(m).Themicrowaveregionspreadsacross1mmto1m;thisincludesalloftheintervalsusedbyradarsystems,whichgeneratetheirownactiveradiationdirectedtowardsandreflectedfromtargetsofinterest.Thelowestfrequencyregion–beyond1m–isassociatedwithradiowaves.雷達系統自己主動產生輻射，發射到感興趣目標并從感興趣目標反射回來。188AbsorptionbandsandatmosphericwindowsSometypesofelectromagneticradiationeasilypassthroughtheatmosphere,whileothersdonot.Theabilityoftheatmospheretoallowradiationtopassthroughvarieswiththewavelength/typeoftheradiation.Thegasesthatcompriseouratmosphereabsorbradiationincertainwavelengthswhileallowingradiationwithdifferingwavelengthstopassthrough.199TheareasoftheEMspectrumthatareabsorbedbyatmosphericgasessuchaswatervapor,carbondioxide,andozoneareknownasabsorptionbands.Absorptionbandshavealowtransmissionvalueassociatedwithaspecificrangeofwavelengths.能夠被水蒸汽，二氧化碳和臭氧等大氣層氣體吸收的電磁波譜區域稱為吸收帶。2010Incontrasttotheabsorptionbands,thereareareasoftheelectromagneticspectrumwheretheatmosphereistransparenttospecificwavelengths.Thesewavelengthbandsareknownasatmospheric“windows”sincetheyallowtheradiationtoeasilypassthroughtheatmospheretoEarth’ssurface.2111Mostremotesensinginstrumentsonaircraftorspace-basedplatformsoperateinoneormoreofthesewindowsbymakingtheirmeasurementswithdetectorstunedtospecificfrequencies(wavelengths)thatpassthroughtheatmosphere.3大多數裝在飛機或太空平臺上的遙感儀器工作在一個或多個這樣的“窗口”范圍里，這是通過將其檢測裝置調諧在能穿透大氣層的特定頻率（波長）上而實現的。2211Whenaremotesensinginstrumenthasaline-of-sightwithanobjectthatisreflectingsunlightoremittingheat,theinstrumentcollectsandrecordstheradiantenergy.Whilemostremotesensingsystemsaredesignedtocollectreflectedradiation,somesensors,especiallythoseonmeteorologicalsatellites,directlymeasureabsorptionphenomena.2311TheatmosphereisnearlyopaquetoEMradiationinpartofthemid-IRandallofthefar-IRregions.Inthemicrowaveregion,bycontrast,mostofthisradiationmovesthroughunimpeded,soradarwavesreachthesurface.2412Pixels,bits,andcolorUsingradiowaves,datafromEarth-orbitingsatellitesaretransmittedonaregularbasistoproperlyequippedgroundstations.Asthedataarereceivedtheyaretranslatedintoadigitalimagethatcanbedisplayedonacomputerscreen.Satelliteimageryismadeupoftinysquares,eachofadifferentgrayshadeorcolor.Thesesquaresarecalledpixelsandrepresenttherelativereflectedlightenergyrecordedforthatpartoftheimage.2513Eachpixelrepresentsasquareareaonanimagethatisameasureofthesensor’sabilitytoresolveobjectsofdifferentsizes.Forexample,theEnhancedThematicMapperontheLandsat7satellitehasamaximumresolutionof15meters;therefore,eachpixelrepresentsanarea15m

15m,or225m2.Higherresolutionmeansthatthesensorisabletodiscernsmallerobjects.Byaddingupthenumberofpixelsinanimage,youcancalculatetheareaofascene.Forexample,ifyoucountthenumberofgreenpixelsinafalsecolorimage,youcancalculatethetotalareacoveredwithvegetation.2614Spacecraftsuseastringof8binarynumbers,whichcanrangefrom00000000to11111111(0to255inthedecimalsystem).With8-bitdata,wecanassignthedarkestpointinanimageto0,andthebrightestpointintheimageto255.Thisproduces256shadesofgraybetweenblackandwhite.Itisthesebinarynumbersthatthespacecraftsendsbackforeachpixelineveryrowandcolumn–andittakesacomputertokeeptrackofeverynumberforeverypixel.2715Anotheressentialingredientinmostremotesensingimagesiscolor.Whilevariationsinblackandwhiteimagerycanbeveryinformative,thenumberofdifferentgraytonesthattheeyecanseparateislimitedtoabout20to30steps.Ontheotherhand,theeyecandistinguish20,000ormorecolortints,enablingsmallbutoftenimportantvariationswithinthetargetmaterialsorclassestobediscerned.2816Sincedifferentbands(orwavelengths)haveadifferentcontrast,computerscanbeusedtoproduceacolorimagefromablackandwhiteremotesensingdataset.Computerscreenscandisplaythreedifferentimagesusingbluelight,greenlightandredlight.Thecombinationofthesethreewavelengthsoflightwillgeneratethecolorimagethatoureyescansee.2916Thisisaccomplishedbydisplayingblackandwhitesatelliteimagescorrespondingtovariousbandsineitherblue,green,orredlighttoachievetherelativecontrastbetweenthebands.Finally,whenthesethreecolorsarecombined,acolorimage–calledafalsecolorimage–isproduced.3017RemotesensingmethodsTherearetwotypesofremotesensinginstruments–passiveandactive.3118Passiveinstrumentsdetectnaturalenergythatisreflectedoremittedfromtheobservedscene.Passiveinstrumentssenseonlyradiationemittedbytheobjectbeingviewedorreflectedbytheobjectfromasourceotherthantheinstrument.Reflectedsunlightisthemostcommonexternalsourceofradiationsensedbypassiveinstruments.Scientistsuseavarietyofpassiveremotesensors.被動儀器只感知被觀測物體發出的輻射或來自某個源而不是儀器的被物體反射的輻射32191.Radiometer:Aninstrumentthatquantitativelymeasurestheintensityofelectromagneticradiationinsomebandofwavelengthsinthespectrum.Usuallyaradiometerisfurtheridentifiedbytheportionofthespectrumitcovers;forexample,visible,infrared,ormicrowave.4

輻射計通常又按其覆蓋的頻譜范圍來區分，例如可見光、紅外、微波。33202.ImagingRadiometer:Aradiometerthatincludesascanningcapabilitytoprovideatwo-dimensionalarrayofpixelsfromwhichanimagemaybeproducediscalledanimagingradiometer.Scanningcanbeperformedmechanicallyorelectronicallybyusinganarrayofdetectors.34213.Spectrometer:Adevicedesignedtodetect,measure,andanalyzethespectralcontentoftheincidentelectromagneticradiationiscalledaspectrometer.Conventionally,imagingspectrometersusegratingsorprismstodispersetheradiationforspectraldiscrimination.35224.Spectroradiometer:Aradiometerthatcanmeasuretheintensityofradiationinmultiplewavelengthbands.Oftentimesthebandsareofahighspectralresolution–designedfortheremotesensingofspecificparameterssuchasseasurfacetemperature,cloudcharacteristics,oceancolor,vegetation,tracechemicalspeciesintheatmosphere,etc.5

這些頻帶經常具有高分辨率，是為特定參數的遙感而設計的，如海面溫度、云地特性、植被、大氣層的微量化學成分等。3623Activeinstrumentsprovidetheirownenergy(EMradiation)toilluminatetheobjectorscenetheyobserve.6主動儀器提供自己的能量（電磁輻射）來照射要觀察的對象或場景。3723Theysendapulseofenergyfromthesensortotheobjectandthenreceivetheradiationthatisreflectedorbackscatteredfromthatobject.Scientistsusemanydifferenttypesofactiveremotesensors.38241.Radar(RadioDetectionandRanging):Radarusesatransmitteroperatingateitherradioormicrowavefrequenciestoemitelectromagneticradiationandadirectionalantennaorreceivertomeasurethetimeofarrivalofreflectedorbackscattredpulsesofradiationfromdistantobjects.7Distancetotheobjectcanbedeterminedsinceelectromagneticradiationpropagatesatthespeedoflight.雷達用一個工作在射頻或微波頻率的發射機來發出電磁輻射，用一個方向性天線或接收器來測量從遠處目標反射或反向散射回來的輻射脈沖的到達時間。39252.Scatterometer:Ascatterometerisahighfrequencymicrowaveradardesignedspecificallytomeasurebackscatteredradiation.Overoceansurfaces,measurementsofbackscatteredradiationinthemicrowavespectralregioncanbeusedtoderivemapsofsurfacewindspeedanddirection.40263.Lidar(LightDetectionandRanging):Alidarusesalasertotransmitalightpulseandareceiverwithsensitivedetectorstomeasurethebackscatteredorreflectedlight.Distancetotheobjectisdeterminedbyrecordingthetimebetweenthetransmittedandbackscatteredpulsesandusingthespeedoflighttocalculatethedistancetraveled.Lidarscandetermineatmosphericprofilesofaerosols,clouds,andotherconstituentsoftheatmosphere.41274.LaserAltimeter:Alaseraltimeterusesalidartomeasuretheheightoftheinstrumentplatformabovethesurface.ByindependentlyknowingtheheightoftheplatformwithrespecttothemeanEarth’ssurface,thetopographyoftheunderlyingsurfacecanbedetermined.42PartIIUsingRemoteSensingtoMonitorGlobalChange43NewWordsinduce感應，遭致wetland濕地hydrologic水文的regime政權，體制，情態marsh沼澤，濕地swamp沼澤，進退兩難之地mangrove紅樹fringe加邊，加飾邊nutrient營養habitat棲息地fur-bearinganimal毛皮動物buffer緩沖erosion腐蝕，侵蝕canal運河，溝渠diversion轉移sediment沉淀物，沉積levee大堤compound復合eustatic

（全球）海面升降的predominant占主導地位的44NewWordspertinent相關的，切題的scenario情節，劇本，方案outpace趕過，超越hydrology水文學drainage排水dynamics動力學salinity鹽度zonation

成帶，分區linkage聯合，結合thematic題目的，主旋律的monotypic單型的portrayal描繪，肖像biomass生物量responsive應答的，回答的inundation洪水，大水contour等高線elevationcontour海拔等高線quadrangle四邊形standarddeviation標準差moisture濕氣，水份451Toproperlyrespondtonaturalandhuman-inducedstressestowetlands,resourcemanagersmustconsidertheirfunctionsandvalues.Remotesensingisanimportanttoolformonitoringwetlandresponsestochangesinthehydrologicregimeandwaterqualitycausedbyglobalclimatechangeandsea-levelrise.監控濕地對于全球氣候變化和海平面上升造成的在水文情勢和水質方面的變化的反應462Extensivemarshes,swamps,andmangroveforestsfringemostoftheU.S.coastline.Besidesbeinganimportantsourceofnutrients,coastalwetlandsarenurseriesforfishandshrimpandhabitatformanybirdsandfur-bearinganimals.Theyarealsovitaltocoastalrecreation,maintainwaterquality,andserveasabufferagainstshoreerosion.1

它們對沿海休閑也是重要的，并且能保持水質，成為防止海岸侵蝕的屏障。473IntheUnitedStates,widespreadwetlandlosshasresultedfromthefillingofmarshlands,constructionofcanalsandwaterways,anddiversionofriversedimentsoffshore.2在美國，濕地萎縮是由沼澤的填充，開挖水渠、河道，河流淤泥向海面轉移造成的。483Soilconservationpracticesandflood-controlstructuressuchasdamsandleveesarepreventingsedimentsfromreachingwetlands.Furthercompoundingthesehuman-inducedstresses,theeustaticsea-levelrisehasseriousimplicationsforcoastalwetlands.Predominantly,thesealevelisrisinggloballyfrom1mmto2mmyearly;however,increasingratesarepredictedtocauseabouta50cmriseinsealevelbytheyear2100.493Theseproblemsareespeciallypertinenttocoastalwetlandswheretherateofelevationrisemayonlybeabout10cmforeachkilometertraversedinland.Ifthegreenhouseeffectisconfirmedaspartoftheglobalclimatechangescenario,eventheselevelswillbeoutpaced.3

這些問題特別切合于海岸濕地，在那里橫跨內陸每一公里的海拔高度上升可能只有10厘米。如果溫室效應被證實是全球氣候變化的部分原因，還要超出這些（上升的）水平。504Coastalhydrologyisdominatedbysurfacetopography,surfacedrainage,soilcharacter,andlocaltidaldynamics.Withanincreasingrateofsea-levelrise,tidaldynamicswilldominatethehydrologychangeswithinlow-lyingcoastalwetlands.海岸水文地理學受控于表面形貌學，地表水系，土壤特征和本地潮汐動態學。514Impactstothesewetlandswillincludechangesinsoilsalinitylevels,floodingdurationandfrequency,andwaterquality.Forecastsofhowthesechangeswillaffectthepresentandfuturewetlandspecieszonationareneeded.Tomaketheseforecasts,itisnecessarytofirstidentifytherelationshipbetweenwetlandtypeandhydrology..524RemotesensingstudiesconductedbyUSGSscientistsfocusedonintegratingground-basedandsatellitemeasurementstodeveloptoolsformeasuringandmonitoringfactorscriticaltodeterminingtheselinkages.4美國地理調查局科學家們所進行的遙感研究集中于將地面和衛星測量結合起來，開發測量和監視對確定這些聯系極為重要的工具。534Theyalsodevelopedtechniquesforgeneratingcoastaltopographytosimulatefuturewetlandchangesbasedonuncoveredlinkagesandsea-levelrisescenarios545Wetlandtypes

AprogressiveclassificationofamarshandforestsystemcombiningdatafromLandsatThematicMapper(TM),colorinfraredphotography,andERS-1satelliteradarwasdevelopedthatimprovedclassificationaccuracyandresultedinadetailedidentificationofdifferenceswithinanearlymonotypicblackmarshinFlorida.5結合從LandsatTM衛星、彩色紅外照片、ERS-1衛星雷達上獲取的數據，構建了沼澤和森林體系的累進分類，改進了分類精度，導致佛羅里達州幾乎單一黑色的沼澤地中有差異地區的細致區分。555Thesetypesofimprovementsinclassifyingcoastallandcoversarenecessarybeforeanaccurateportrayalofthelinkbetweenvegetationcharacteristicsandhydrologycanbemade.566VegetationbiomassVegetationindexesrelatedtobiomassmeasuresweregeneratedfrompassivemicrowavedataandLandsatTMdata.TheopticalTMvegetationindexbasedonredandnear-infraredwavelengthsisprimarilylinkedtochangesingreenbiomass.576Themicrowavevegetationindexbasedonmeasuringenergyemittedat6cmand21cmmicrowavewavelengthsisprimarilyresponsivetothevegetationwatercontent.Theimagesarenoticeablysimilar.Ifthemicrowaveinstrumentprovestobeanadequateestimatorofbiomassinthesewetlands,amonitoringprogramcouldbedevelopedaroundthisall-weather,day-and-nightsensor.587MonitoringfloodingSatelliteradarwasusedtomaptidalflooding,acriticalcontrolofcoastalvegetationdistribution.Radarimagestakenduringatimeofnear-continuousrecordingsofgroundbas