The primary goal of this project is to develop new monthly estimates of changes in ocean heat and freshwater content. The ocean absorbs more than 90% of the excess heat associated with the Earth’s energy imbalance, and spatial patterns of sea level changes are regulated by both heat and freshwater content, emphasizing the. importance of this work. While observations of ocean temperature and salinity needed to determine heat and freshwater content are sparse, improvements can be made by systematically testing mapping methods, employed to obtain global fields from the observations, in ocean models and by including additional sources of data that need bias adjustments before usage. The project is designed to perform these types of method testing and bias corrections through collaborations with other groups on a national and international level. The outcomes of the project will help advance our understanding of past and future changes in ocean heat and freshwater content which is important for the health of the planet, economies, and communities. Sharing of data products and software and dissemination of the results will make the outcomes of the project openly available to the community. This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Opportunity. This Opportunity allows a single joint US/UK proposal to be sub