 Soil moisture was recently added to the list of essential climate variables, ECVs, which are deemed necessary for intergovernmental panel on climate change, IPCC, and United Nations Framework Convention on Climate Change, UNFCCC, needs. To ensure consistency and accuracy, soil moisture data must be collected from multiple sources, such as scatterometers and radiometers, with frequencies ranging from low to high. The C-band scatterometers on board the ERS and METOP satellites, along with multi-frequency radiometers SMMR, SSM slash I, TMI, AMSRE, and WINSAT, have already provided data for over 30 years. The challenge now is to combine these data into one consistent record. 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, funded by the European Space Agency, ESA, and will be further developed through the Climate Change Initiative, CCI, program of ESA. This article was authored by W. Wagner, W. Derigo, R. Dejeu, and others. We are article.tv, links in the description below.