"Recent Developments in SAR Remote Sensing"
Synthetic aperture radar (SAR) data provide unique
information about
Earth's surface and vegetation cover, including critical
data for natural
hazards and resource assessments. The ability to optimize
viewing geometry
and acquire data independent of cloud cover and illumination
conditions
provides detailed information about vegetation for assessing
changes in
land cover, biomass and forest regrowth. Interferometric
SAR measurements
can be used to generate topographic data sets, monitor
surface topographic
change, and measure glacier ice velocity.
Single-frequency, single-polarization interferometry data
continue to be
acquired by the European Remote-sensing Satellites (ERS),
Japanese Earth
Resources Satellite (JERS), and Canadian Radarsat. Recent
large scale
mapping activities such as the Antarctic Mapping Mission
and Global Rain
Forest Mapping Project have shown the value of these
sensors as important
complements to optical and passive microwave monitoring
tools.
NASA's SAR Program has focussed on demonstration of advanced
SAR sensors
using Shuttle and aircraft platforms. These have led
to several new
mission concepts including a Topography and Topographic
Change Mission,
Cold Land Processes Mission, and Vegetation Recovery
Mission. NASA has also
partnered with the National Imagery and Mapping Agency
to use SAR
interferometry to generate a digital topographic map
of 80% of Earth's land
mass as part of the Shuttle Radar Topography Mission.