Hydrology

Hydrology is the scientific study of water in the environment, focusing on the distribution, movement, and properties of water on Earth. It encompasses various aspects of the water cycle. We explore how microwave radar technology is utilized to detect and measure water storage in different forms, such as snow (snow water equivalent), soil (soil moisture), vegetation (vegetation water content), and surface inundation. Microwave radar operates by transmitting signals at specific frequencies (most commonly L/C/X/Ku-band) to the land surface and receiving the scattered signals. These signals can be received at the same location (monostatic radar, such as Synthetic Aperture Radar, or SAR) or at different locations (bistatic radar, bistatic SAR, and reflectometry).

Microwave frequencies have the ability to pass through the atmosphere and interact directly with the vegetation and land surface. The scattered signals, including their amplitude and phase, depend on the dielectric constant of the reflecting surface, which is primarily influenced by the water content. By analyzing the returned signals, we can determine the electrical properties of the land surface and correlate them to water content. This radar remote sensing approach enables us to continuously monitor various water storages globally, such as soil moisture, snow water equivalent, and vegetation water content, therefore enhancing our understanding of the hydrologic cycle and the underlying physical processes.

Scientists in the Radar Science group have made important contributions in the general area of Hydrology remote sensing including in