Remote sensing instruments: Sensor types relevant to wetlands

Abstract

A wide range of sensors are available for providing information on wetlands, both in the past and in near real time. The Landsat series of sensors has been providing data since the 1970s, and these provide a unique record of the changing extents and states of water across the globe. Using these data, a number of regional or global maps of annual water inundation have been generated. Coarse resolution optical sensors such as MODIS provide more regular observations of water and have been used to better understand water flows and snow accumulation and melt across landscapes. Microwave sensors operating at X, C, and L band have also provided high to moderate resolution cloud free observations of wetlands on a regular basis since the early 1990s and are particularly useful to quantifying changes in wetland extent and dynamics, including in areas where forest cover is dense. Airborne and spaceborne LIDAR have mainly been used to retrieve information on the three-dimensional structure of vegetation. Stereo-optical data, lidar, and radar can also indicate the topography of the underlying surface, which is useful in hydrological modeling. A number of missions are anticipated to increase the amount of information on wetlands, with these including the Copernicus Sentinel missions.