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NISAR:TheNASA-ISROSARMission

Sinkholes SinkholeactivityisamajornaturalhazardinCentralFlorida,causing $200 million per year in property damage. Inlimestone areas sinkholes form after circulatinggroundwater has dissolved the rock under the surface.When a cavity has grown too big to support the overlyingland, a sinkhole opens. Catastrophic collapses are likelypreceded by subtle subsidence of the land surface by an

inch or less over periods of weeks to years. NISAR is anadvanced radar system that can measure grounddisplacements of a fraction of an inch. With a repeatinterval of 12 days and a spatial resolution of 100 squarefeet. NISAR can potentially identify surface movementindicativeofundergroundactivitybeforeasinkholeforms.

ObservingHazardsandtheEnvironmentofFloridaFlorida

Florida’smildclimate,beautifulbeaches,exoticlandscape,andabundantwildlifemakeitapopulardestinationfortouristsfromacrosstheglobe.Florida’sresiliencytothreatstothesenaturalwonderscanbenefitfromNISAR’sobservationsofsinkholes,hurricanes,flooding,andthehealthoftheEverglades.

Florida’s Delicate Environment

Florida’sbeautyistheresultofthebalancebetweenlow-lyingcoastalareas,wetlands,andtheshallowoceancombinedwiththesubtropicalclimate.Whenhumanssettledalongthecoast,theyweresubjectedtothehazardsassociatedwithrisingseas,coastalerosionandriskfromstormsurgesandflooding.Meanwhileunderthesurface,newlyintroducedsaltwatercaninfiltrateintotheporouslimestone,threateningthewatersupplyandcoastalecosystems.MonitoringthesehazardsandthechangingenvironmentisvitalforthepreservationofFlorida.

The NISAR Mission – Reliable, Consistent Observations TheNASA–ISROSyntheticApertureRadar(NISAR)mission,acollaborationbetweentheNationalAeronauticsandSpaceAdministration(NASA)andtheIndianSpaceResearchOrganization(ISRO),willprovideall-weather,day/nightimagingofnearlytheentirelandandicemassesoftheEarthrepeated4-6timespermonth.NISAR’sorbitingradarswillimageatresolutionsof5-10meterstoidentifyandtracksubtlemovementoftheEarth’slandanditsseaice,andevenprovideinformationaboutwhatishappeningbelowthesurface.Itsrepeatedsetofhighresolutionimagescaninformresourcemanagementandbeusedtodetectsmall-scalechangesbeforetheyarevisibletotheeye.

Photos(clockwise):USGS,FEMA,NOAA,NPS

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Rising Sea Levels The hazards in Florida’s coastal areas, particularly stormsurges associated with hurricanes and nuisance floodingduringhightides,areexacerbatedbyrisingseas.Morethan10%oftheState’spopulationof21millionliveatelevations4” or less above the high tide level. The southeast Floridacounties,collaboratingthroughtheregionalClimateChangeCompact,arepreparing their cities for12”-26”higher seasby2060,requiringsignificantpublic investments.Thisdoesnot include measures to secure the water supply, and itremains unknown when wells will turn salty. Long-termplanning is difficult because the sea level projections are

uncertain. What is known is that Florida’s fate is closelylinkedtothefateofthepolaricesheetsandtoGreenlandinparticular. A 1% reduction of the mass of the ice sheetswouldleadtoglobalsealevelriseof2feet.Theicesheetsarelosingmassbymeltingatthesurfaceandbyacceleratedflow of the glaciers. The upcoming NISAR mission willprovidefrequentandregularmeasurementsofthespeedofthe polar glaciers to determine whether the glaciers areaccelerating. These observations will inform sea levelprojections and better planning for low-lying Floridacounties.

NationalAeronauticsandSpaceAdministration Formoreinformation,visithttp://nisar.jpl.nasa.gov/applications

JetPropulsionLaboratory/CaliforniaInstituteofTechnology/Pasadena,California/www.jpl.nasa.gov

TheEvergladeswetland,alsoknownastheRiverofGrass,notonlyprovidesarefugeforthesouthFlorida’sresidentsanduniquewildlife,butitisalsoadriverforthetourismindustryandprotectslow-lyingterrainfromtheadvancingocean.Evergladesrestorationandconservationisatopenvironmentalpriorityatboththestateandfederallevel.TheupcomingNISARmissionwillcontributeinthemonitoringofthehydrologicalsystemandhowthewaterflowsfromLakeOkeechobeetoFloridaBay.Thesatelliteiswell-suitedtodetectchangesinthewaterlevelbetweentwoconsecutiveimages,andwillprovideatimeseriesofthewaterlevelacrosstheentirewetland.Right:SatelliteradarinterferogramofsouthFloridafromtwoimagesacquiredinfall2015bytheEuropeansatelliteSentinel-1A.Onecolorcyclerepresentsa3cmchangeinwaterlevel.ThewhitearrowshowswhereflowishaltedbytheTamiamitrail.

Wetlands

Whenahurricaneapproaches,FloridiansrelyonforecastsbytheNationalHurricaneCenterforpersonaldecisionsabouttheirsafety.Whereastheforecastsofthehurricanetrackshaveimprovedsignificantlyoverthepastdecade,intensityforecastsremaindifficult.Overtheopenoceans,in-situobservationsaresparse.NISAR’sall-weatherday/nightradarinstrumentcanmeasurehowtheoceansurfacehasbeenagitatedbytheforcefulwinds,providingsurfacewindspeedinformationtobettermodelandforecasthurricanes. Synthetic Aperture Radar image (left) and optical satellite images (right) ofHurricane Katrina on August 2005 were acquired by the European SpaceAgency’s satellite Envisat. The radar senses the ocean surface,whereas theopticalscannersensesthetopoftheclouds.Theeyeofthehurricaneappearsdarkintheradarimage,becausethewindislessforcefulinthisarea.

Hurricanes

Credit:EuropeanSpaceAgency

Credit:S.-H.HongandS.Wdowinski