Remote Sensing of Applications in Hydrology

Abstract

Remote sensing is the science of observing and analyzing an area, object, or phenomenon based on data collected by sensors physically separated from the target. The sensors are mounted on platforms such as ground‐based, airplane, or satellite platforms. Physical radiation transfer is the foundation for remote sensing. Typically, the observation is of radiation reflected or emitted from the object of interest. There are two types of remote sensing: active and passive. In active remote sensing, the object is illuminated by radiation of a known wavelength (or frequency); the backscatter from the object is recorded by the sensor. In passive remote sensing, the sensor records radiation generated from natural sources, such as the sun, or radiation emitted from the earth or atmosphere. Radiation that the sensor receives has a spectral response that reveals properties of the atmosphere and object of interest. By extending remote sensing applications to improve the spatial and temporal resolution of certain key water resource variables, scientists can better understand and quantify water resource processes.