Natural Hazards Observer
| March 2005 | Volume XXIX | Number 4 |
Invited Comment
Remote Sensing Technology:
A Coming of Age
Author’s Note: July 13, 2004. It’s a balmy afternoon at the Natural Hazards Workshop in Boulder, Colorado. I have just presented at a plenary session on the Bam, Iran, earthquake (my contribution: building damage detection using satellite imagery) and am chatting afterwards to members of the disaster management community. As a remote sensing specialist, I am gratified to hear that “the eye in the sky” is now well and truly on their radar screen as a tool for disaster management. With the following invited comment, let me guide you through some of the momentous developments of the past few years that are bringing remote sensing technology to the fore.
The Millennium Heralds New Capabilities
The turn of the century marked a quantum leap forward for remote sensing. We said goodbye to the resolution-limited 1990s, where we could see the immense potential that this technology had to offer, but had yet to realize it, and where the best imagery of heavily damaged earthquake zones merely depicted a cluster of fuzzy bright areas. Although satellites such as Landsat helped us pinpoint hard hit areas, we could only dream of ascertaining detailed information about the number of collapsed buildings and severity of damage. But today, remote sensing has “come of age;” the dream has become a reality. This coming of age is a function of two major factors: technology push and user pull.
Technology Push
For disaster-related applications, resolution and accessibility are driving the technology push. Resolution refers to three domains crucial for this sort of analysis: spatial, temporal, and spectral. At this very moment, very high-resolution commercial satellites may be imaging your backyard. I am not promising that these satellites can read your vehicle license plate, but with a 60 centimeter resolution, the QuickBird imaging system can certainly pick vehicles out on the freeway. Analysts may even be able to discern automobiles from pickup trucks.
From a temporal perspective, areas are imaged more frequently as pointable systems are developed and new satellites are added to the global constellation. Although “real-time” imaging remains a push for the future, rapid download centers like the Center for Rapid Environmental Assessment and Terrain Evaluation offer twice-daily MODIS (moderate resolution imaging spectroradiometer) coverage for fire monitoring. For earthquake, tsunami, or hurricane damage assessment, QuickBird, Ikonos, or OrbView coverage is available within days. Delivery times for a disaster site will continue to fall as additional submeter resolution systems, such as Worldview and Pleiades, are launched. The Disaster Monitoring Constellation also promises rapid data acquisition for its member nations: the United Kingdom, China, Algeria, Nigeria, Vietnam, Turkey, and Thailand.
Spectrally, optical and radar systems are extremely complementary. Optical imagery captures the unfolding scene as it appears to the human eye while radar offers day and night coverage and can see through clouds. Over the next few years, radar will exhibit its own technology push. The COSMO-Skymed (Constellation of Small Satellites for Mediterranean Basin Observation) four-satellite constellation promises 1-meter data, a significant improvement on today’s 8.5-meter Radarsat data.
In regard to the role of data accessibility in this technology push, commercial satellite companies like DigitalGlobe recognize disaster response requirements and have worked hard to streamline the data acquisition and customer delivery processes. From personal experience, I have ordered imagery one day after a disaster and received it via rapid ftp download the following day. Although this timescale already supports postdisaster reconnaissance and response planning needs, new doors will be opened once the challenge of real-time user download is met.
From a policy perspective, several major international initiatives have also improved accessibility. In 2000, nations throughout the world committed to extend the use of space facilities for disaster response through the United Nations Charter on Space and Major Disasters. Members activate the charter after major events, and data providers collect and serve imagery from optical and radar systems including Ikonos, Spot, and Radarsat. To date, the charter has been activated more than 60 times, including in the aftermaths of the Southeast Asia tsunami, Hurricanes Frances and Ivan, floods in Argentina, and the Bam earthquake. The European Space Agency’s online Earth Watching Service complements this initiative by providing coverage from Landsat, ERS (European Radar Satellite), and JERS (Japanese Earth Resources Satellite) sensors. Closer to home, the Federal Emergency Management Agency Web site features remote sensing coverage of U.S. events.
User Pull
In recent years, the disaster management community has seen an increase in the deployment of remote sensing technologies for both natural and human-caused events. The benefits are multifaceted and include detailed visualization, regionwide assessment, safe surveying of dangerous areas, timely information about inaccessible locations, and a permanent record of perishable damage. The following examples are some of my favorites.
For natural disasters, such as earthquakes, hurricanes, and tsunamis, satellite imagery is beneficial as a data source and is being deployed in conjunction with conventional ground-based activities. For the 2003 Bam earthquake, I was personally involved in situation assessment activities, using high-resolution before and after images to generate citywide damage maps for reconnaissance teams. These are particularly useful for overseas events, where the outflow of information is slow or inaccurate. The imagery has since been used to estimate the number of collapsed structures, a capability that in the future could provide rapid casualty estimates.
The Earthquake Engineering Research Institute (EERI) was one of the first international reconnaissance teams to deploy remote sensing technology operationally as a tool for prioritizing field survey activities. The remote sensing driven VIEWS (visualizing the impacts of earthquakes with satellite images) system was first deployed to Bam, Iran, after the earthquake, where it guided the team to hard-hit areas and enabled them to track the progress of recovery efforts. VIEWS is a notebook-based system, developed for multihazard reconnaissance through funding from the Multidisciplinary Center for Earthquake Engineering Research. It integrates before and after satellite imagery with real-time GPS (global positioning system) readings and map layers and operates in conjunction with a digital video recorder and digital camera. It has since been deployed by the EERI Niigata earthquake reconnaissance team and by a joint United States-Thailand-Japan team in Thailand after the 2004 tsunami.
Remote sensing technologies were applied following Hurricane Charley to accelerate and streamline postwindstorm damage assessment. The Wind Science Engineering and Research Center at Texas Tech University has responded to more than 120 windstorms since 1970. In the past, damage was assessed via walking tours, with key indicators and the overall damage state logged manually on a spreadsheet. In this case, VIEWS provided a permanent visual record of perishable damage data for approximately 2,500 buildings per day, instead of the usual 20-100, saving money as well as time.
Following the World Trade Center attack, remote sensing and GIS (geographic information systems) activities were centralized at the Emergency Mapping and Data Center. Optical, lidar, and thermal imagery provided ground teams with a detailed overview of ground zero and the evolving cleanup operations. They provided firefighters with valuable new information about the relationship between fires and fuel sources beneath the debris pile and supported the strategic planning and evaluation of response activities. Overlaying a two-dimensional grid with optical imagery also created a reference system for tracking objects amongst the debris. A similar grid approach was employed in the regionwide search effort after the Columbia Space Shuttle disaster.
In addition to these response functions, remote sensing is also playing a role in preparedness activities. For example, the California Governor’s Office of Emergency Services recognizes the value of satellite imagery as a data source and is currently supporting the development of methodologies for updating HAZUS (Hazards U.S. loss-estimation software) databases. The operational deployment of earth observation products within decision support tools will become increasingly widespread in the years to come with the National Aeronautics and Space Administration (NASA) serving as a driving force. NASA’s “Disaster Management Program Element Plan: 2004-2008,” states the following goal: “enable partners’ beneficial use of Earth science research results, observations, models, and technologies to enhance decision support capabilities serving their disaster management and policy responsibilities.” Accordingly, NASA is currently funding projects to develop integrated systems solutions that assimilate remote sensing products into nationally-important decision support tools, such as HAZUS-MH (multihazard), SLOSH (Sea, Lake, and Overland Surges from Hurricanes), and FARSITE (Fire Area Simulator), used by federal, state, and local governments as well as nongovernmental organizations.
A Final Word
The coming of age that remote sensing is currently experiencing is being driven by a combination of technology push and user pull. The door is open for future technological pushes towards new constellations and real-time user download. I welcome stories about your deployment of satellite technology.
Beverley Adams
ImageCat Inc.
bja@imagecatinc.com
Internet Resources
http://www.imagecatinc.com/
ImageCat Inc.
http://www.mceer.buffalo.edu/
Multidisciplinary Center for Earthquake Engineering Research
http://www.eeri.org/lfe/recent_recon.html
Earthquake Engineering Research Institute Learning from Earthquakes program
http://www.digitalglobe.com/
DigitalGlobe (high-resolution satellite imagery provider)
http://www.sstl.co.uk/
Surrey Satellite Technology Ltd. (developer of the international satellite Disaster Monitoring Constellation)
http://www.spaceimaging.com/
Space Imaging (high-resolution satellite imagery provider)
http://aiwg.gsfc.nasa.gov/esappdocs/progplans/DM_Program_Plan_2004_v7.doc
NASA’s “Disaster Management Program Element Plan: 2004-2008”
http://www.disasterscharter.org/main_e.html
2000 Charter on Space and Major Disasters
http://www.gismaps.fema.gov/rs.shtm
FEMA Mapping and Analysis Center—Remote Sensing
http://earth.esa.int/ew/
European Space Agency Earth Watching service
Lessons Learned Information Sharing—LLIS.gov
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