The International Soil Moisture Network - An observational network for soil moisture product validations

In situ soil moisture measurements are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. On a worldwide basis the number of meteorological networks measuring soil moisture is still limited and their data lack standardization of technique and protocol. In response to this, the International Soil Moisture Network (ISMN) was initiated to serve as a centralized data hosting facility where globally available in situ soil moisture measurements from operational networks and validation campaigns are collected, harmonized, and made available to users through a web interface, while downloads are provided according to common standards for data and metadata. Currently the network contains data of 16 networks with more than 400 stations and is rapidly expanding. As the ISMN is fed and utilized by the scientific community it will become a valuable resource for validating and improving satellitederived soil moisture products and studying climate related