 Soil moisture was recently added to the list of essential climate variables, ECVs, which are necessary for climate change research and monitoring. To ensure consistency in accuracy, it is important to use multiple data sources such as scatterometers and radiometric radiometers. These instruments have been collecting data for over 30 years, and it is important to combine them into one consistent dataset. One potential solution is to merge the level 2 soil moisture data from each sensor. This approach has already been tested in the WACMOS project, and will be further developed under the European Space Agency's Climate Change Initiative Program. This article was authored by W. Wagner, W. Derigo, R. Dejeu, and others.