Radar returns to remote sensing through free, near-real-time global imagery
Satellite imagery has transformed how we assess changes in forest cover.
The standard optical sensors carried by Earth-orbiting satellites capture the energy from sunlight reflected off objects on the Earth’s surface. These sensors recognize levels of brightness and color in the reflectance, which enables users to distinguish between greener and browner vegetation, or row crops and savannah, as well as among objects, such as tree species, with different chemical properties.
They cannot, however, see though clouds. Clouds block the reflectance data from reaching the sensor, which limits the effectiveness of even high-resolution (3-5 meter) satellite data, such as Planet or DigitalGlobe, in rainy regions like the Amazon.
The Monitoring of the Andean Amazon Project (MAAP), which uses remote sensing data to highlight deforestation hotspots in the western Amazon and activities that cause forest loss, has addressed this challenge with an alternative, 80-year-old technology—radar.