The objective of this project is to develop a statistical model that integrates a range of observational data to improve estimates and projections of vertical land motion (VLM). The approach will leverage and expand a mature statistical technique designed to incorporate disparate sources of observational data and model output to produce rate and robust uncertainty estimates of VLM. The framework will be used to produce the highest resolution possible - as determined by the research in this project - VLM estimates over differing spatial domains, targeting the production of estimates along the U.S. East Coast at sub-kilometer resolution at Department of Defense (DoD) installations, and on a global scale for a point-based set of global DoD installations, tide gauges and on a one-degree or higher resolution coastal grid.

The traditional approaches used to estimate VLM and the available direct observations of VLM all come with limitations that impact the ability to understand current rates and project future contributions. Combining established statistical models with available observations, model outputs, proxy reconstructions, and reanalysis data provides a path to improving upon available estimates by incorporating a wide variety of data streams covering relevant space and time scales. Specifically, leveraging a Bayesian Hierarchical Model framework, Global Navigation Satellite System, Interferometric Synthetic Aperture Radar, satellite altimeter (both radar and laser), proxy relative sea level reconstructions from saltmarsh sediment cores and other natural archives, tide gauge and groundwater data can be integrated alongside modeled glacial isostatic adjustment contributions in a mathematically coherent and consistent manner to isolate the localized rate of VLM. This framework will provide robust estimates of uncertainty, and will also allow for indirect measures of the drivers of coastal VLM to be included, such as groundwater recharge and depletion, which is essential for understanding the non-linearity of VLM and how to project estimated rates into the future.

This project will provide consistent screening-level estimates of VLM both for the region of focus (U.S. East Coast) and on global scales to match the scope of the DoD mission. The deliverables of this project are designed for seamless integration into the Defense Regional Sea Level (DRSL) database. As currently developed, the DRSL database provides consistent information on future sea-level rise across all installations. The project team has constructed this project with a strong view toward implementation into the DRSL database, recognizing that providing estimates for only specific regions would lead to installations without information. The approach takes advantage of the rich information that is already available as opposed to devoting resources to developing additional data products that cannot meet the specific need of generating estimates that are representative of future VLM along the coasts. This work also has the potential to advance the state of knowledge of data assimilation and data integration, as well as the understanding of the physical processes that drive VLM across time and space scales.