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structure of vegetation on the Earth’s terrestrial surface and its 
influence on habitat, agricultural and timber resources, fire 
behavior, and economic value; (3) mapping soil moisture with a 
horizontal resolution (several meters) that is not otherwise 
attainable; (4) characterizing the contributions of ground water, 
surface water, soil moisture, and snow pack to the global fresh 
water budget, etc. 
2.8 Near-real-time InSAR processing for hazards 
monitoring 
To characterize and monitor landscape change and ground 
surface deformation associated with natural hazards with 
InSAR imagery, a system is needed that can automatically 
process and manage large amounts of SAR data. In addition, the 
system should be capable of cataloging, archiving, and 
retrieving the processed InSAR images and associated products. 
A Web-based Graphical User Interface (GUI) that is 
independent of computer platforms can be used to interface the 
InSAR processing system so that InSAR processing and 
deformation map generation are accomplished through a few 
simple steps of a shopping-basket procedure. The automated 
InSAR processing system and the associated GUI can lay out 
the foundation for real-time processing of InSAR images to 
monitor ground surface deformation due to earthquake, volcano, 
or °th er processes. Because more satellite radar sensors and 
radar satellite constellations will become available in the next 
decade, the automated SAR/InSAR processing system for 
hazard monitoring is of paramount importance for near-real- 
time decision support. 
3. CONCLUSION 
InSAR is one of the fastest growing fields in Earth science and 
remote sensing. The precise land surface topography and the 
time-transient variability provided by InSAR systems will 
accelerate development of predictive models that can anticipate 
the behavior of many natural hazards such as volcanic eruptions, 
earthquakes, landslides, and others. In addition, InSAR will 
provide tools to better characterize the contribution of ground 
water, surface water, soil moisture, and snow to the global fresh 
water budget and the role of glaciers and ice sheets in sea-level 
rise and global warming. Furthermore, InSAR will offer the 
capability of imaging the three-dimensional structure of 
vegetation on a global scale for improved characterization and 
management of the Earth’s resources. With more and more 
operational SAR sensors available for rapid data acquisitions, 
armed with state-of-the-art information technologies such as 
data-mining and grid computation, InSAR will continue to 
address and provide solutions to many scientific questions 
related to natural hazard monitoring and characterization. 
Acknowledgments. ERS-1/-2 and Radarsat-1 SAR images are 
copyrighted by the European Space Agency (ESA) and 
Canadian Space Agency (CSA), respectively, and were 
provided by the Alaska Satellite Facility (ASF) and ESA. This 
work was supported by funding from the National Aeronautics 
and Space Administration (NASA), the U.S. Geological Survey 
(USGS) Land Remote Sensing Program, the USGS Volcano