New concepts for space-borne Tsunami early warning using microwave sensors

Off-shore detection of tsunami waves is a critical component of an effective tsunami warning system (TWS). Even more critical is the off-shore detection of local tsunamis, namely tsunamis that strike coastal areas within minutes from the triggering quake. In this presentation we propose two new concepts for tsunami detection. NESTRAD (Near-Space Tsunami Radar) consists of a real aperture radar accommodated inside a stationary stratospheric airship providing continuous monitoring of tsunamigenic oceanic trenches. G-SAR consists of one or two geosynchronos satellites carrying a radar designed for SAR applications. We also propose a concept for a passive radar on a very small LEO platform, using GNSS signals for altimetry and reflectometry (based on the PARIS concept, Martin-Neira, 1993). However, a large constellation of such passive sensors is necessary to assure the required temporal coverage