Disaster, Recovery & Reconstruction: Using IFSAR and Satellites for Decision Support John Douglas and Carl H. Menges Apogee Imaging International, Web: www.apogee.com.au Abstract The human and economic costs from natural disasters are having an ever more dramatic impact on nations in the Asia-pacific region. Given this situation, it is imperative that governments are seen to be active in improving their disaster management planning, both politically and in practise. Spatial information from satellite and airborne sensors is a potentially powerful tool for assisting disaster management. The technology is under utilised by many countries in the Australasian region, where it could provide significant benefits in preparing for the most common and inevitable disaster events, such as flooding, drought and forest fire. Four distinct management phases can be identified in respect of a natural disaster: preparation, early-warning, emergency, and reconstruction. Remote sensing data has been shown in numerous research projects to observe disaster impacts after the event, and some studies have attempted to use the data for the early warning of landslides and floods, but little has been done to employ the technology to increase community and emergency services disaster-preparedness or assist in the operational procedures during the emergency situation. The lack of inclusion of remotely sensed data is justified to some degree because it does not yet represent a total solution, with limited acquisition opportunities and relatively high costs for large-scale applications. This presentation will demonstrate the benefits of spatial information in supporting the decision making process in each of the disaster management phases given the current and future sensor availability. 1. INTRODUCTION Disasters are becoming more frequent and have greater social/economic cost. While it is not universally accepted that climate change is responsible for the increasing number and severity of disasters, it is clear that the trend can not be ignored. Flooding, drought and big forest fire are the main natural disasters in Australasian and East Asian countries. Therefore, it is imperative to establish systems for mitigating these natural disasters. Disasters often impact large or remote geographic areas and present substantial communications and information challenges:
While existing international support networks are available to provide spatial resources and other information in case of emergencies, the ability to utilize such support efficiently is dependent on the level of preparedness by those affected by and managing the disaster. Considering the increasing frequency and magnitude of disasters, the approach to natural hazards requires a change of paradigm. One must shift from reactive action after an event has occurred to management of the risk and being prepared for such events. Up-to-date reference maps and images, personnel training in the effective use of geo-spatial data, ensuring a state of preparedness of all inhabitants, and establishing emergency protocols for communication are essential parts of disaster risk mitigation. With appropriate and timely information, everyone who may suffer from the consequences of events should be able to take the most appropriate action before, during and after a disaster and thus seriously limit damages. This paper explores the level of support spatial information can provide in the preparation, emergency response and recovery phases of floods and fire events, which constitute the major threat to the Australasian nations. Apogee Imaging International www.apogee.com.au supplies high resolution optical and radar satellite imagery, aerial IFSAR radar imagery, digital elevation models, and multispectral imagery and image processing services. Established in 1995 APOGEE is focussed on fast delivery and high fidelity data. Our core business is the supply of data for: Federal and State Government, Terrestrial and Maritime Surveillance, Corridor Mapping and Analysis, Support to the Petroleum and Mining Industries, Detailed Topographic Mapping, Emergency Services Support, Agribusiness, Natural Resource Monitoring, Major Construction projects, Local Government and Telecommunications Modelling. 2. SPATIAL INFORMATION FOR EMERGENCY SUPPORT 2.1 Existing International Support Networks Global Disaster Information Network (GDIN) “GDIN is a voluntary, independent, self-sustaining, non-profit association of nations, organizations, and professionals, from all sectors of society including NGO's, Industry, Academia, Governments, and International Organizations with an interest in sharing disaster information. The aim of GDIN is to provide the right information, in the right format, to the right people, in time to make the right decisions.” (http://www.gdin.org/) Sharing of information for disaster relief is a primary concern of GDIN. The organization was formed in response to frustration by experts, who either found it hard to find relevant, existing information in short order, or couldn't efficiently or cost effectively change existing information into more useful formats. The GDIN services include:
The International Charter was formed in November 2000 and aims at providing a unified system of space data acquisition and delivery to those affected by natural or man-made disasters through authorized users. Each member agency has committed resources to support the provisions of the Charter and thus is helping to mitigate the effects of disasters on human life and property.  Upon receipt of a request by an authorized user all space resources are mobilized to acquire data in response to an emergency event. Data acquisition and delivery takes place on an emergency basis, and a project manager, who is qualified in data ordering, handling and application, assists the user throughout the process. “The Charter is based on voluntary contributions, by all parties, of Earth observation satellite data. Its main purpose is to supply states or communities whose populations are exposed to risk or have been affected by a natural or technological disaster with data providing a basis for anticipating and managing potential or actual crises.” (http://www.disasterscharter.org) DMC “The Disaster Monitoring Constellation (DMC) was designed as a proof of concept constellation, capable of multispectral imaging of any part of the world every day. It is unique in that each satellite is independently owned and controlled by a separate nation, but all satellites have been equally spaced around a sun-synchronous orbit to provide daily imaging capability.” (http://www.dmcii.com)  The daily revisit capability is derived from the coordinated orbit placement and the large area coverage of 600x600km. DMC has agreed to participate in the International Charter and members provide 5% of capacity free to the imaging of disaster areas. 2.2 Spatial Information Support for flood mitigation Earth Observation (EO) can contribute to improve flood management. Space-derived information can be a valuable source of up-to-date geo-information for flood risk mapping (prevention), for flood forecasting (preparedness phase) and for the crisis and post-crisis phases dealing with flood extent mapping and damage assessment. It is impractical to acquire the flood area through field investigating. The methods to extract flood extent from remotely sensed images such as TM, FY-IB and NOAA AVHRR are explored by a few persons (Zhou et al. 1997). Microwave remotes sensing is very useful for monitoring flood events because it can obtain useful image without obstruction by cloudy conditions. It has been shown that flood extent can be automatically extracted from JERS SAR image in plain area (YangCunjian et al. 1998) and Radarsat data in combination with Landsat TM has been shown to allow the extraction of flood extent in mountainous areas (Yang Cunjian 1999). RADARSAT in particular offers a high turnaround interval, from when the data is acquired by the sensor, to when the image is delivered to the user on the ground. The land / water interface is quite easily discriminated with SAR data, allowing the flood extent to be delineated and mapped. The SAR data is most useful when integrated with a pre-flood image, to highlight the flood-affected areas, and then presented in a GIS with cadastral and road network information. Flood extent mapping conducted during and immediately after the disaster provides emergency planners, managers, and relief agencies with data and information necessary to respond to the immediate disaster recovery needs of citizens and communities. Satellite Earth observation technology can play role in the flood and waterlogging monitoring:
The DEM should provide information in regard to the bare surface rather than the tops of vegetation. This can be achieved with P-Band mapping from a SAR sensor as microwave radiation at this wavelength is insignificantly attenuated by vegetation. The Intermap IFSAR sensor with its new capability of polarimetric interferometry in P-Band is particularly suited to this task as the difference in scattering centre heights from the co- and cross-polarised signals of the two bands provides additional information to allow improved interpolation of absolute ground and vegetation height. To improve the capability of communities to withstand flood disasters, inundation potential maps provide valuable information for precaution, regulation, management, and mitigation measures against such disasters. For example, regulation policy can be ruled to ban land development of areas with high vulnerability to hazards. Emergency warning systems and response measures can be constructed and planned with information characterized in hazard potential maps. Structural measures can be designed with better capacities to sustain disaster demolition by locating areas of having high disaster risks from hazard maps. Flood insurance rate-zone maps can be generated based on regional flood vulnerability from inundation potential maps. Identification of safe areas and appropriate evacuation routes is important information for all inhabitants and high resolution satellite data, with a DEM, is an efficient tool for this purpose. Risk of landslides and trafficability of roads under severe conditions can be assessed. At present, Landsat ETM+ is a cost-effective tool for mapping landslide susceptibility, due to its relatively low cost and high spectral resolution. However, its spatial resolution remains a significant limitation. This limitation is avoided by utilizing high resolution multi-spectral data from sensors such as Orbview3, which allows small landslides to be mapped in detail. RADARSAT or other satellite SAR image pairs can be used to produce in-SAR models to monitor surface changes in the centimeter range. This is a powerful tool over areas of potential landslide, volcanoes and fault lines, to monitor subtle deformation and subsidence as early warnings of coming disasters. Satellite imagery forms an essential decision making tool in land management. In relation to disasters, this is of particular importance as natural assets can significantly reduce the impact of events. Mangrove forests, for example are able to absorb energy from a tsunami event. The risk of landslides is dramatically reduced if deforestation on steep slopes is prevented. The availability of images after a disaster has occurred is a good tool for experienced personnel. Its value, however, is greatly increased if comparable data has been acquired before the event to allow for change detection and prepare emergency staff in working with this data. Thus governments need to budget to acquire data over areas likely to be subjected to natural or man made disasters. After a disaster has occurred, a unique opportunity exists to plan the rebuilding of infrastructure and housing with consideration to the topographic features of the landscape. While the political difficulties are not solved by spatial information, it provides a decision making tool for more effective rebuilding of urban areas often planned in the 18 th century or earlier. 2.3 Spatial Information Support for fire risk mitigation Global hotspot maps are produced on a regular basis from AVHRR and MODIS data. These provide a valuable tool in the early detection of fire events. Satellite data is, however, not yet a operational tool during a fire as there are no geostationary medium resolution imaging satellites available. Increasing capabilities and availability of sensors will change this situation in the future. At present the existing ability to use spatial information to prepare for fire events is not fully utilized. Apogee Imaging International has been developing an image based tool for fire management called FIREYE™. FIREYE uses satellite and aerial data to build an accurate, geocoded 3-D image model of the fire scape. This “Virtual Landscape” can be used in pre-fire season planning and training, during a fire as a visualization tool in which other data can be fused, and for forensic discovery and learning post fire. Apogee and CISCO are partnered in this program working together to build a robust point-to-point delivery system for FIREYE, enabling interactive contact between fire fighters, command centres and the citizens threatened by the fire. Satellite data could be used to maintain up-to-date topographic and road maps, to map risk zones, identify road access problems in terms of fire risk and ability to turn a fire truck if necessary. Preparation of emergency personnel could be facilitated by the production of 3-D terrain models with inbuilt scenarios. This would be of particular value, where fire fighters from other areas, who lack local knowledge, have to be called upon. Personnel who have been familiarized with spatial information products are then in a position to fully utilize such information when disseminated during an emergency. 'Fire hazard categorization' is vital for emergency planning in order to minimize loss of lives and property. Recording hazard levels help in understanding the spatial distribution of fire susceptibility and vulnerable areas and assist in the 'Allocation' and 'Mobilization' of dynamic resources. Tracking of fire fighting efforts via a GPS feed would provide the command centre with a better overview to base decisions on as well as providing a mechanism to record the actions. This would provide a tool for improving future actions, when implemented as a scenario, as well as a legal record. 3. NEW RESOURCES FOR EMERGENCY SUPPORT The Availability of Spatial Information Support is improving with a greater number of sensors in space and on aircraft and an improved capacity of new sensors. According to a recent analysis by Forecast International, "The Market for Civil and Commercial Remote Sensing Satellites," approximately 170 remote sensing satellites will be manufactured between 2004 and 2013, 130 of which are slated for production within the next five years. The commercial and civil remote sensing market can be broken down into two categories: Geosynchronous Earth Orbit (GEO) systems and Low Earth Orbit (LEO) systems. The GEO systems carry a high cost because of their complex payload and are mostly used to monitor global climate and the weather conditions on Earth. As for LEO systems, the top unit producer is expected to be Surrey Satellite Technology Ltd (SSTL), which is projected to earn 11.9 percent of total unit production over the next 10 years. Surrey Satellite's Disaster Monitoring Constellation (DMC) is one of the major components in this category, simply because it offers a wealth of remote sensing knowledge and capabilities to nations that otherwise could not have developed such technology on their own in the near term. Following SSTL in terms of market share is the European favorite Astrium, which is expected to capture 8.8 percent and the Indian Space Research Organization, ISRO, with about 8.1 percent of the LEO market. Forecast International believes that faster data distribution rates and enhanced imagery processing and packaging services will drive the growth of the remote sensing market. Further, the prohibitive costs associated with high resolution images make them unobtainable for institutions with limited budgets. For this reason, Edwards said, "government agencies will remain the largest consumer of remote sensing goods and services until increased competition eventually brings prices down." TerraSAR-X is a next generation, high resolution satellite operating in the X-band at 9.65 GHz. The launch of the 1-ton satellite into a 500-km orbit is planned on a Russian/Ukrainian rocket for April 2006. TerraSAR-X will provide a continuous stream of remote sensing data for at least 5 years. The derived products will support numerous scientific and commercial applications. With innovative technology such as active antennas, the satellite is capable of producing 1m resolution data and wide area coverage of 100km swath width independent of weather and daytime. Radarsat 2 is to be launched next year with a fully polarimetric mode and a fine resolution mode of 3m. Amongst the optical satellites planned is RapidEye, a configuration of five high resolution satellites providing daily coverage of any part of the globe. Aerial remote sensing goes back even further than satellite remote sensing. However, it was not until recently that breakthroughs in system and software technology produced a surge in commercial remote sensing applications and experimentation. A range of sensors can be deployed using aerial platforms today. This includes standard photography of course as well as LIDAR, SAR, thermal and hyperspectral data. The increased accuracy of GPS positioning with precise systems on jet aircraft has allowed the achievement of high quality data with precise geometric information. The IFSAR system operated by Intermap can produce a georectified digital elevation model with0 .5 -5m vertical and 2m horizontal spatial resolution, independent of cloud cover at any time of the day or night. Intermap’s introduction of fully polarimetric P-Band interferometry in combination with x-band IFSAR is a capability that is not expected to be available on a space-borne system for some time to come. The advantage of P-Band is its ability to penetrate foliage and provide a true, rather than interpolated, DTM of the bare earth. IFSAR data is the system of choice to map in the tropics and other cloudy areas and where the client has a deadline for data collection. For example Intermap IFSAR can collect up to 100km2 of imagery and DEM in a minute for less than $100/km2. In the future High-Altitude Unpiloted Aerial Vehicles (HAUAVs), may become cost effective platforms for IFSAR, further reducing the cost and allowing loitering over a disaster for up to 24 hrs and real time transmission of data to the area impacted. Another application of HAUAV’s is maritime surveillance over remote areas such as Antartica. This technology also raises regulatory issues in relation to the commercial remote sensing business that collects, processes, and sells data and imagery. (http://www.space.edu/libraryresearch/Remote_sensing_article.html 4. CONCLUSION The number and severity of disasters is increasing and all governments have a responsibility to mitigate the associated risks to their citizens and their property. Given adequate preparation, the impact of events can be reduced significantly. The case being made here is that remotely sensed data is currently under utilized in preparing for disaster events despite the valuable contribution it could make. Spatial information derived from satellite and airborne sensors forms a crucial basis in the effort to adequately prepare for emergency situations. An outline has been provided to the use of spatial information for flood and fire risk mitigation. There is a significant commonality in the use of these data for those disaster events. An assessment of vulnerability combined with the preparation of escape routes and education of emergency personnel and the public at large is the most important near term requirement. Regular mapping of infrastructure, assets and land use are of key importance when an event occurs, as is the ability to correlate post-event data quickly and accurately for damage assessment and emergency response operations. A sudden influx of data after an event has occurred is of limited help without baseline data and without a broad base of emergency workers, who are trained to understand and use the data. Finally, one of the greatest difficulties is the delivery of the image data directly to the end user in the field when and where it is needed; this is what Apogee and CISCO are building for the near future.
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