More than 30 years of observations from an international suite of satellite altimeter missions continue to provide key data enabling research discoveries and a broad spectrum of operational and user-driven applications. These missions were designed to advance technologies and to answer scientific questions about ocean circulation, ocean heat content, and the impact of climate change on these Earth systems. They are also a valuable resource for the operational needs of oceanographic and weather forecasting agencies that provide information to shipping and fishing vessels and offshore operations for route optimization and safety, as well as for other decision makers in coastal, water resources, and disaster management fields. This time series of precise measurements of ocean surface topography (OST)—the “hills and valleys” of the ocean surface—reveals changes in ocean dynamic topography, tracks sea level variations at global to regional scales, and provides key information about ocean trends reflecting climate change in our warming world. Advancing technologies in new satellite systems allows measurements at higher spatial resolution ever closer to coastlines, where the impacts of storms, waves, and sea level rise on coastal communities and infrastructure are manifest. We review some collaborative efforts of international space agencies, including NASA, CNES, NOAA, ESA, and EUMETSAT, which have contributed to a collection of use cases of satellite altimetry in operational and decision-support contexts. The extended time series of ocean surface topography measurements obtained from these satellite altimeter missions, along with advances in satellite technology that have allowed for higher resolution measurements nearer to coasts, has enabled a range of such applications. The resulting body of knowledge and data enables better assessments of storms, waves, and sea level rise impacts on coastal communities and infrastructure amongst other key contributions for societal benefit. Although not exhaustive, this review provides a broad overview with specific examples of the important role of satellite altimetry in ocean and coastal applications, thus justifying the significant resource contributions made by international space agencies in the development of these missions.

The 10th Surface Water and Ocean Topography (SWOT) Applications Meeting, held one year after the satellite's launch, highlighted significant milestones in mission progress and showcased the innovative work of SWOT Early Adopters (EA) using mission data products. Over 100 participants from diverse sectors convened to discuss operational applications leveraging SWOT's unprecedented water surface measurements. The meeting emphasized applied science efforts to enhance hydrology and oceanographic models. This summary highlights the breadth of operational and private‐sector uses of SWOT data, emphasizing its potential to drive new innovations and deliver societal benefits, such as improved water resource management, flood prediction, and climate resilience.

A continuous global satellite radar altimetry data time series spanning 32 years has made significant advances in research and operational applications possible. The TOPEX/Poseidon satellite mission, launched in 1992, was intended to test technology and data systems to precisely measure height variations across the ocean-“ocean surface topography” (OST) -on a global scale from space. The mission performed so successfully that it was followed by the “Jason-series” satellites; Jason 1, Jason 2, Jason 3, and the newest, Sentinel 6 Michael Freilich, with more satellites in the series in preparation. These U.S.-European collaborations have significantly enhanced understanding of ocean and coastal dynamics and have made large-scale reservoir and lake observations since 1992. The 2022 launch of the Surface Water and Ocean Topography (SWOT) mission has further advanced knowledge of ocean dynamics and extends observations to high-resolution land surface water observations. OST data have been crucial in monitoring global sea level rise, understanding ocean circulation and heat content, and supporting coastal impact assessments and climate modeling. Beyond research, OST observations benefit operational oceanographic and water resource organizations and weather forecasting agencies worldwide. They inform shipping, fishery and marine operations, and decision-making and disaster management in coastal zones. The continuous OST record aids in analyzing trends, tracking sea-level rise, assessing ocean health, and supporting climate change mitigation strategies. Partnerships between NASA, the French space agency, Centre National d'Etudes Spatiales (CNES), NOAA, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Space Agency (ESA), and the European meteorological and EUMETSAT have been instrumental in developing an essential climate data record, providing substantial value to both research and operational communities. This talk, summarizing findings from [1], will highlight the OST time series' value and applications in ocean-focused operations and private sector use.

Thirty years of altimetry satellite observations have provided important information that enables research discoveries and aids in the development of user-driven applications. National and international space and operational agencies have committed substantial resources to developing and continuing observations of the ocean and large water bodies (lakes, reservoirs, large rivers) through collaboration in these missions. Over the next few years, NASA and other agencies will launch new research missions with technologies that will extend, expand, and evolve observations of ocean, coastal and inland waters. New discoveries and advances in societally relevant applications can be leveraged with increased spatial, temporal and spectral resolutions. We will highlight the use of data from these existing and planned missions for operational and applied user-driven applications and their societal benefits. Topics may include the use of existing, retrospective, and expected time series that contribute to applications such as marine operations, marine biology and biodiversity, coastal studies, hurricanes and other hazards, as well as hydrologic assessments, water resources management, and other surface water applications.

An international partnership of space agencies has contributed a continuous time series of more than thirty years of global satellite altimetry data. Beginning with TOPEX/Poseidon, and proceeding through the Jason 1, 2, and 3 satellite missions, Sentinel-6 Michael Freilich, and the newest Surface Water and Ocean Topography (SWOT) mission, this U.S./NASA, France and European partnership has enabled important research discoveries and has significantly aided in the development of several valuable operational and commercial, user-driven applications. Substantial resources have been committed over the decades by national space agencies to advance both the science and applications outcomes of these missions. Over the next decade NASA and partners will launch several new satellites with technologies that will extend and expand this constellation even further, providing a rich resource to support science and operational applications. New discoveries and advances in societally focused applications will be enabled by the increased spatial and temporal resolution of satellite remote sensing data that will continue to support ocean, coastal, and hydrology operations and decision makers. Here we highlight existing and potential uses of data from these missions for such applications for societal benefit. Applications areas include marine operations, fisheries and marine biodiversity, coastal planning, and water resource management. We share information on the NASA programs in place to advance and engage with these applied user communities, and on opportunities to collaborate in our efforts.

Planning is underway for development of the next NASA Mass Change satellite mission, as identified in the National Science Foundation’s 2017-2027 Decadal Survey for Earth Science and Applications from Space  (Decadal Survey). NASA has identified a Mass Change Designated Observable (MCDO) Study Team to evaluate satellite mission architectures that could optimally support a range of science and applications needs of user communities (both research and operational) of future mass change missions (i.e., successors to the GRACE and GRACE Follow On missions). The primary science objective of the MCDO, as identified in the Decadal Survey, is the continued measurement of changes in the Earth’s dynamic gravity field over time. The Decadal Survey also emphasizes applications of the mission data products as a major focus, in addition to science outcomes. Operational use and societal benefit derived from the GRACE and GRACE FO data and information products demonstrate the value of these missions. Applications include drought monitoring, quantification of groundwater depletion, flood prediction, and thermal expansion of the ocean, which contributes to sea level rise, to name a few. In order to effectively identify the observational product requirements of future gravity mission applications data users and to develop actionable objectives for mission design, a Mass Change Mission Applications survey was developed. Information on user needs, current uses, and capabilities derived from the survey have provided insights as to desired or required spatial scales, data latency, data formats, and technical capabilities of the users, as well as how to prioritize tradeoffs. The survey focused on evaluating the needs of a broad range of existing and potential user communities in order to incorporate these needs into mission design and architecture studies that are underway.The survey comprises general questions about requirements for a given application, and data use and demographic information to help characterize aspects of the user community. Analyses of the survey results are now being used to inform potential mission architecture designs, evaluate tradeoffs, and ensure that the data products are optimized for a broad user community.