Space Technology for Global Water Resources Observations

Abstract

Since the launch of the Radar Altimeters on-board ERS-1 and TOPEX/POSEIDON 19 years ago, significant advances in all facets of Radar Altimetry have resulted in a high accuracy over the open ocean to the centimeter level. Over inland water bodies such as rivers, lakes and reservoirs, the measurements are tenfold less precise, however it is recognized by the scientific community that, with special processing algorithms which are constantly being improved, useable results are obtained to support observations of watershed systems. This paper reports upon the strategic outlook for exploiting the current and future potential of Radar Altimetry missions and other space-borne data products to monitor surface water storage. The scope of this technique is to monitor thousands of river and lake heights worldwide, with the access to almost two decades of historical data now permitting analysis of trends and identification of climate signatures.

The results illustrate the current capability and future potential of these approaches to derive a global picture of the Earth’s inland water resources, depicting each catchment basin, worldwide, and to identify both climate signatures and regions where human usage is depleting the resource beyond its capacity to recharge.

Important progress has been made recently in using Satellite data for hydrology, juxtaposed with in-situ data and the modelling effort. Particular attention is paid to the support of management and preservation of water resources, a key aspect of environmental security, by supplying to both scientists and managers accurate global datasets, for large scale, trans-boundary and local scale monitoring frameworks, particularly where and when there are no in-situ hydrological measurements available. Space borne measurements are global in nature, usually with a free and open access data policy, which is the case for the future operational observing “Sentinel” satellites of the European Global Monitoring for Environment and Security Programme, and as such their worldwide scientific exploitation contributes to peace and security.