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Table 4-3. Disaster management cycle and the use of different types of data sets 341Phase Data Type Example Data SetsPreparednessand EarlyWarningUser-generatedSensorTwitter (food crisis, earthquake), web traffic (flu)Precipitation (PERSIAN, TRMM, planned GPM), evapotranspiration, soil moisture, temperature,vegetation density and water content (MODIS, LANDSAT, Sentinels), groundwater levels (GRACE)Impact andResponseUser-generatedSensorCDR, Flickr, Twitter, SMS trafficOptical imagery (LANDSAT, MODIS, DigitalGlobe, SPOT, Pleiades, RapidEye SkyBox, PlanetLabsetc.), thermal (LANDSAT, MODIS), radar (RADARSAT-1, TerraSAR, Alos, Sentinels, CARTOSAT),georeferenced videoMitigation, Riskand VulnerabilityModelingUser-generatedSensorCDR, emergency call content, FacebookNighttime Lights (NTL), Imagery, thermal, Radar, spatial video, Temporal Flood Inundation Mapping(GIEMS, DFO, etc.)institutional, publicGCM (Global Climate Model), Transportation data (subway, bike share), census, Landscan,Worldpop, Open Cities4.4.1. Preparedness and Early WarningBig data both from individuals and from various sensors(space-based, aerial or ground-based) can contribute toenhancement of early warning systems and disasterpreparedness.Using sensors to detect weather patterns has a wellestablishedhistory, and meteorological data collectionsdates back over a hundred years. For instance, it has beenuseful in predicting floods 342 , droughts 343 , fires 344 , andENSO (El Nino Southern Oscillation) driven drought 345 .Satellite imagery can also be used as a source for earlywarning for epidemics, by using spatial modeling tocorrelate disease cases with land use characteristics andcreating risk prediction maps to inform health agencies, ashas been done with malaria, Rift Valley fever 346 , andschistosomiasis 347 .By using “citizens as sensors” 348349 , often referred to ascrowdsourcing, many crises can be predicted before theyoccur, allowing for lead-time for evacuation and othercrucial preparations. For example, the UN Global PulseProgram was able to predict three separate food crises inIndonesia in 2012 by filtering tweets by using key wordsabout price and inflation 350 . Public health professionalshave also used online searches as an early warning to fluoutbreaks, as disease outbreaks correlate with queries of83disease for early detection 351 . Earth observation derivedimagery has also been combined with precisely geo-locatedfield users’ generated information in FLOODIS 352 , acollaborative European Community project. It aims atproducing alerts and management information on incomingand occurring floods events with high- accuracy, providing acentralised platform for emergency responders andcitizens.4.4.2. Impact and ResponseBoth individual data and sensor data can play a key role inthe immediate aftermath of a disaster in support ofhumanitarian aid allocation, in rapid damage assessmentand in the response phase in monitoring progress.Over the last decade, efforts from the major space data andspace-based information providers have focused mainly onthe response phase of disasters, including theestablishment of successful operational support servicessuch as the International Charter on Space and MajorDisasters 353 and the Sentinel Asia 354 that aim at providing aunified system of space data acquisition and derivedmapping products delivery to those affected by natural orman-made disasters. Traditional satellite imagery data canbe used for disaster impact assessment by surveying thespatial extent of impact for floods 355 , fires 356 , landslides 357 ,drought 358 , and more, when the right data and techniquesare employed. Satellite Earth observation offers unique