The DISCOVER Project (Distributed Information Services for Climate and Ocean Products and Visualizations for Earth Research) is funded under the NASA Earth Science Research, Education and Applications Solutions Network (REASoN) program. The primary objective of DISCOVER is to provide carefully calibrated, long-term ocean and climate products suitable for the most demanding Earth research applications via easy-to-use display and data access tools. The products included in the project are global sea surface temperatures, ocean surface winds, atmospheric water vapor, and daily cumulative rain rates, all derived from both past and currently active satellite microwave sensors. A key element of DISCOVER is the merging of data from the multiple sensors on multiple platforms into geophysical data sets consistent in both space and time. This poster will introduce the DISCOVER merged microwave water vapor product and provide validation results. This water vapor product is being used in several important studies. A summary of the studies and outcomes will be shown.