Imaging of Earth’ Ecosystems with Synthetic Aperture Radar Technology
Josef Kellndorfer, Woods Hole Research Center
Remote sensing of our home planet can be likened to "Radiology of Patient Earth". Just like in medical imaging, we need a range of techniques, like X-rays, CAT scans, or MRI. The observation with cloud-penetrating, all-weather imaging Synthetic Aperture Radar (SAR) at medium (10-100 m) resolution has a long history, yet has not found its way into the mainstream operational monitoring in a way optical remote sensing has over the past 40 years. This is rapidly changing with the increased availability of SAR data from a variety of international missions. Open data policies for SAR data with operational observing strategies are now in place, foremost Europe’s C-band ( ~ 5 cm wavelength) Sentinal-1 mission. And, after 1978, NASA is poised to launch an L-band (~ 23 cm wavelength) SAR in cooperation with the Indian Space Agency (ISRO) in 2020. This talk provides an overview of recent research conducted with regional to global-scale SAR data in fusion with optical and lidar (i.e., laser) remote sensing data sets to generate invaluable data sets on terrestrial biomass, vegetation structure, and monitoring of ecosystem dynamics in the U.S. and across the tropics. These data sets are invaluable to further our understanding on the global carbon cycle on the one hand, but also find practical applications in policy frameworks for carbon emission reduction strategies from forest managements as discussed under a United Nations or emerging bi-lateral Climate treaties. We discuss how SAR processing obstacles of the past are overcome with modern SAR time-series processing techniques, and thus and how the cloud-free data streams from SAR observations are quickly evolving as an indispensable resource for continuous Earth observation in the future.