Much of geomorphology depends on accurate topographic data. Satellites have transformed our ability to capture such data from planetary surfaces over the last 2 decades. Truly global datasets were only first released in the late 1990s; in 1997, a 5 arcminute dataset (roughly 10-km-wide pixels at the equator) was released, followed in the same year by a 30 arcsecond dataset (GTOPO30; roughly 1-km-wide pixels at the equator). The widespread use of global topographic datasets for geomorphic applications began with release of the Shuttle Radar Topography Mission's (SRTM) 3 arcsecond product in 2004 (roughly 90 m wide at the equator). SRTM data allowed, for example, the extraction of river profiles, slope maps at the hillslope scale, and floodplains. In the last decade, improvements in both the resolution and quality of topographic data have accelerated rapidly. Global 30 m data was released in 2009 (ASTER), followed by commercial 5 m (ALOS World 3D) and 12 m (TanDEM-X DEM) products in 2016. This chapter gives an overview of the history of satellite-derived topographic data products. It discusses the different instruments used and techniques available for generating topographic data from space. It then reviews the accuracy and availability of topographic datasets and discusses the implications for geomorphic research. Finally, it discusses the potential for future satellite missions to improve global topographic information.
|Name||Developments in Earth Surface Processes |