The terrestrial water cycle incorporates the transportation of water (solid/liquid/water vapour) within all land and atmospheric processes on the Earth. This includes precipitation, surface run-off, river flow, surface-water and groundwater storage and fluxes, and evapotranspiration, to name just a few. The study of this subject is key to many research areas, for example impacts on climate change, agriculture, ecology and biogeochemistry, as well as to practical human needs, such as irrigation and hydroelectricity. The processes involved in the terrestrial water cycle are highly complicated, as well as extremely variable. Standard in-situ measurements are often unable to capture this variability, as they are usually point measurements. Remote sensing offers the potential for large scale, high-resolution, multi-temporal, multi-sensor measurements, with the possibility of large amounts of data stretching over space and time. When combined with rapidly developing computational and modelling resources, remote sensing is an invaluable tool. This book presents numerous examples of how remote sensing can be applied in a way to aid in the study of some areas of the terrestrial water cycle. Specific topics covered include soil moisture, water vapour content, storm structure, sea surface temperature, precipitation, ocean colour, river dynamics, water clarity, ocean outfall plumes, diatom ocean phenology, river discharge, black water events and ocean signals. Remote sensing data types and techniques that are described include the derivation of spectral indices from multispectral satellite imagery, the use of data derived from satellite imagery as inputs for atmospheric correction, radar and lidar data, microwave and scatterometer data, spatial analysis of ocean properties and feature extraction and change detection.