A Strategy for a Global In-Situ Soil Moisture Network

Soil moisture is more and more recognized by the international scientific community as a key variable in the description of hydrospheric processes (IGOS-P IGWCO 2004) and is recognized by the GCOS community as an emerging essential climatic variable (ECV) (GCOS, 2004). The need for a monitoring system in the terrestrial domain to measure soil moisture is therefore of increasing importance. The monitoring from space borne systems will enable global coverage but to be of real value these data need to be validated properly over large domains and longer time spans. Currently no global network exists of in-situ soil moisture measurements and soil moisture is only routinely measured in certain basins and areas in the world. The most complete collection of in situ soil moisture measurements, mostly gravimetric, is in the Global Soil Moisture Data bank (GSMDB) (Robock et al., 2000) and data from this database are frequently used for model validation purposes. The GSMDB data are retrospective in nature and new data come available with a time lag. Hence, these data are less usefull for validation purposes of new earth observation data. To establish a valuable global network the measurements needs to be congruent of nature to avoid cross calibration and data interpretation issues. Establishing and maintaining such a network needs considerable funding. Organisations that work in the area of hydrology and hydrometeorological measurements need to be aware of the importance and value of such measurements. Within this presentation an overview will be given of the rationale of the global in-situ measurement network, the envisaged measurement protocol and the funding opportunities and possibilities References [1] GCOS, 2004. Implementation Plan for the Global Observing System for Climate in Support of the UNFCC. WMO, OIC of UNESCO, UNEP and ICSU. [2] IGOS-P IGWCO, 2004. The Integrated Global Water Cycle Observations theme of the Integrated Global Observing Strategy for the Monitoring of our Environment from Space and from Earth. [3] Robock, A., K. Ya. Vinnikov, G. Srinivasa, J.K. Entin, S.E. Hollinger, N.A. Speranskaya, S. Liu and A. Namkhai, 2000. The global soil moisture data bank. Bull. Amer. Meteor. Soc., 81, 1281-1299