Final&Exam&Review&Material&GEOG/GEOL&4093/5093&Things&I&expect&you&to&know&• How&InSAR&works.&&– How&can&it&detect&precise&relaJve&displacement&– Why&is&it&only&relaJve?&• How&alJmetry&works&• How&scaMerometry&works&• How&GRACE&works&• Spectral&signatures:&DefiniJon&and&importance&• What&is&BRDF&and&why&we&need&to&know&it&• RelaJve&SpaJal&resoluJon&of&various&sensors&(i.e.&which&ones&are&on&the&order&of&a&meter,&15‐80&meters,&100‐500&meters,&one&km,&tens&of&km&• What&is&the&Earth&Observing&system&(objecJves,&how&they&would&be&achieved)&– What&is&the&funcJon&of&the&EOSDIS&– Pathfinder&projects&• Current&and&planned&missions.&What&they&do,&and&how&they&work&• All&of&the&instruments&on&Terra.&What&their&funcJon&is,&what&parts&of&the&spectrum&they&operate&in&• Key&sensors,&and&how&they&work&for&observing&the&following&phenomena&– Clouds&(coverage&and&verJcal&disJrbuJon)&– Aerosols&(spaJal&extent&and&verJcal&distribuJon&– Components&of&the&energy&budget&(outgoing&and&incoming&radiaJon)&– Earth&DeformaJon&and&movement&of&glaciers&– Rain&– Snow&(area&and&water&equivalent)&– Sea&ice&– Soil&moisture&– Geological&mapping&– Health&and&extent&of&vegetaJon&cover.&&– Winds&over&the&ocean&– Ocean,&land,&and&ice&sheet&topography&– Surface&temperatures&Pass 1: Before Motion Pass 2: After Motion Phase Difference Repeat&Pass&Inteferometric&SAR&InSAR‐Derived&Displacement&Phase Difference of ¼ wavelength Example: C-Band InSAR Wavelength = ~ 5.6 cm Phase shift of ¼ wavelength (π/2) = difference in travel time of ~1.25 cm/2 Corresponds to a displacement of 0.625 cm InSAR can measure relative displacements of a few mm from space This is the equivalent of the distance of a human hair from about 600 m awaySatellite&Baselines&Satellite Position 1 Satellite Position 1 Phase Shift between two signals caused by path difference Path Difference Ground In reality, satellites don’t repeat exactly the same orbit, there is some offset that changes the phase of the return signalInterferogram&Showing&Displacement&from&Landers&Earthquake&in&1992&One&cycle&of&color&corresponds&to&2.8&cm&of&displacement&Al4metry&Provides&precise&elevaJon&of&a&surface&by&measuring&travel&Jme&of&a&pulse&(lidar&or&radar)&to&a&surface&hsat&=&ct/2;&&&Hsfc&=&Hsat&‐&hsat&&&&Hsat&=&height&of&satellite&above&Earth&c& &=&speed&of&light&t& &=&pulse&travel&Jme&Hsfc& &=&height&of&surface&above&Earth’s¢er&Hsat& &=&height&of&satellite&above&Earth’s¢er&Range&ResoluJon&Δh&=&cτ/2&Δh &=&range&resoluJon&&&τ &=&pulse&duraJon&• How is the global Earth system changing? • What are the primary causes of change in the Earth system? • How does the Earth system respond to natural and human-induced changes? • What are the consequences for human civilization? • How will the Earth system change in the future? • Understand and improve predictive capability for changes in the ozone layer, climate forcing, and air quality associated with changes in atmospheric composition • Enable improved predictive capability for weather and extreme weather events • Quantify global land cover change and terrestrial and marine productivity and improve carbon cycle and ecosystem models • Quantify the key reservoirs and fluxes in the global water cycle and improve models of water cycle change and fresh water availability • Understand the role of oceans, atmosphere, and ice in the climate system and improve predictive capability for its future evolution • Characterize and understand Earth surface changes and variability of Earth’s gravitational and magnetic fields • Expand and accelerate the realization of societal benefits from Earth system science High&Level&Earth&Science&QuesJons&and&ObjecJves&at&NASA&Earth Observing System (EOS) Artists impression of Spot 5 The overarching goal of the Earth Observing System (EOS) Program is to determine the extent, causes, and regional consequences of global climate change The extent (e.g. the change in average temperature and the time scale over which it will occur) is presently unknown Causes have a natural component and a human-induced component Both must be understood to determine how to alter human behavior appropriately to avoid climate changes that prove most detrimental to the environmentEarth Observing System (EOS) Goals& &Develop&an&understanding&of&the&total&earth&system,&and&the&effects&of&natural&and&human&induced&changes&on&the&global&environment& &Expand&scien4fic&knowledge&of&the&earth&system&using&NASA’s&unique&capabili4es&from&the&vantage&points&of&space,&aircraG,&and&in&situ&plaHorms& &Disseminate&informa4on&about&the&earth&system& &Support&na4onal&and&interna4onal&environmental&policy&recommenda4ons&Mission&objec4ves& &Create&an&integrated&scien4fic&observing&system&that&will&enable&mul4disciplinary&study&of&earth&system&science& &Develop&a&comprehensive&data&and&informa4on&system,&including&a&data&retrieval&and&processing&system& &Acquire&and&assemble&a&global&database&emphasizing&remote&sensing&measurements&from&space&over&a&decade&or&more& &Improve&predic4ve&models&of&the&Earth&System&&Artists impression of Spot 5Artists impression of Spot 5 XArtists impression of Spot 5Artists impression of Spot 5Artists impression of Spot 5Artists impression of Spot 5Services provided by EOSDIS Artists impression of Spot 5 User Support – through 8 Distributed Active Archive Centers (DAACs) Data Archive, Management and Distribution Information Management – Date Gateway that provides “one-stop-shopping” Product Generation – Data product generation from EOS data products Spacecraft Command and Control – Space craft and instrument planning and scheduling, and command and control Data Capture and Telemetry Processing – Capture all data from all EOS spacecraft and process them to remove telemetry errors and make available to NOAA in 3 hoursArtists impression of Spot 5 NOAA/NASA Polar Pathfinder Programs The Pathfinder program was jointly created by NASA and NOAA through the Earth Observing System (EOS) Program Office The focus of the Pathfinder Program is to determine how existing satellite based data sets could be processed and used to study global change
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