Remote Sensing of the Water Cycle
A section of Remote Sensing (ISSN 2072-4292).
The aim of the Section Remote Sensing of the Water Cycle is to contribute to merge together new observations and models for an integrated investigation of the terrestrial water cycle in all its components. This Section publishes original articles, letters, reviews, and communications with regard to the remote sensing of the water cycle and related fields. Special issues propositions are welcome especially when dealing with multidisciplinary approaches to water cycle understanding.
The water cycle is commonly thought to be the circular cycle of evaporation, condensation and precipitation. Although this is somewhat true, the reality is much more complicated since terrestrial ecosystems are involved and the soil-vegetation components are part of the circular mechanism through percolation, plant uptake, evapotranspiration, infiltration, runoff, and storage and flow of groundwater. Exchange of energy is also involved leading to temperature changes through storage and release of latent heat because of phase changes. These heat exchanges influence the climate of the Earth and need to be accounted for in climate models.
Enormous quantities of water are trapped in the polar ice caps, which contribute to the ocean and atmosphere circulation as well as to the balance of salty and fresh waters. The poles are now in constant modification under climate change conditions with unprecedented effects on the ecosystems and possible future influences on sea level height and the amount of freshwater in the oceans.
Glaciers are another freshwater storage that is rapidly changing with ice melting under the influence of increasing temperatures. Mountain ecosystems are then subject to rapid changes reverberating on plants and animals.
The evaporation purifies water thus contributing to make available freshwater for use of man and animals. The flow of liquid water and ice transports minerals and is also involved in reshaping the geological features of the Earth, through erosion and sedimentation.
Given the global as well as the regional character of the water cycle processes, remote sensing helps considerably in monitoring the mechanisms of the water cycle and their sudden or long time changes. It is in fact unthinkable to monitor all these complex and interacting processes using simply ground-based or airborne instruments and sensors. Satellite passive (radiometers in the infrared and microwave) and active (lidars and radars) sensors are essential in keeping the Earth under constant observations using a constellation of satellites in all kinds of orbits for measuring precipitation, soil moisture, atmospheric water vapor, winds, evaporation, ground water through gravity measurements and much more.
All the above mentioned satellites make available large long time datasets that start being of sufficient quality for climate studies. It is essential that the remote sensing community contributes to a synergic exploitation of these datasets for gaining a first-hand picture of the processes and their changes.
- Remote sensing of
- liquid and solid precipitation;
- water storage in the atmosphere, clouds and water vapor;
- evaporation, sublimation, condensation and evapotranspiration;
- soil moisture;
- infiltration, discharge, runoff and storage of water;
- water storage in ice and snow, glaciers, ice fields and snow fields;
- snow melt runoff;
- Satellite missions for the water cycle
- Water cycle, climate and ecosystems
- Radiometer and radar applications for the quantification of the water cycle components
- Synergy of remote sensing and models for the water cycle equation: P (precipitation) = E (evaporation) + R (runoff)