Signature of the Atlantic Meridional Overturning Circulation in the North Atlantic Dynamic Sea Level

The dynamic sea level (DSL) is closely linked to the Atlantic Meridional Overturning Circulation (AMOC) through the geostrophic balance, and is an important fingerprint of the variability and change of the AMOC. The primary goal of this proposal is to systematically investigate the AMOC-DSL relationship in various model integrations, to utilize the long-term DSL observations to detect decadal to multi-decadal variability and long-term trend of the AMOC, and to assimilate the DSL information into the predictability and decadal prediction studies of the AMOC. To achieve the goal, we will use a set of state-of-the-art ocean and climate models, in particular, a consistent data-model framework developed at the Geophysical Fluid Dynamics Laboratory (GFDL) of NOAA, to investigate the robust and accurate relationship between the AMOC and the DSL in the North Atlantic and along the east coast of the U.S. We will compare and combine the DSL data from the high-quality tide gauge records and satellite altimetry, with various model integrations including ocean climate reanalysis, hindcasts, model control and historical runs, and simulations under different external forcings. The objectives are a) to investigate the different sensitivity of the coastal DSL north and south of Cape Hatteras to the AMOC; b) to identify robust DSL patterns in the ocean interior associated with the variability and change of the AMOC; c) to reconstruct the AMOC during the past century based on the DSL information and the AMOC-DSL relationship; and d) to improve prediction and projection skills of the AMOC, the DSL in the North Atlantic, and regional and global climates.

The project will be accomplished through innovative research and educational activities. Through collaborative work with colleagues at GFDL and the University of Arizona, and interactions with students and the general public, this project will make significant contribution to the scientific community and the education of future climate scientists and the general public. The results from this proposal will be made available to broader ocean, climate variability and change and sea level rise research communities, local governments and policymakers. They will contribute to the Coupled Model Intercomparison Project (CMIP5), the Coordinated Ocean-ice Reference Experiments (CORE), and the model development community at GFDL.

This proposal targets and is closely relevant to the following competition: ESS – Atlantic Meridional Overturning Circulation (AMOC): Mechanisms & Decadal Predictability. The NOAA’s long-term goals, as outlined in NOAA’s Next-Generation Strategic Plan, include improved scientific understanding of the changing climate system and its impacts, and assessments of current and future states of the climate system that identify potential impacts and inform science, service, and stewardship decisions. We anticipate that the outcome of this project will meet NOAA’s goals by deepening our understanding of the long-term variability and change of the AMOC, revealing the robust AMOC-DSL relationship in past, current and future climates, and providing reliable decadal predictions and long-term projections of the AMOC. The proposal will also generate near-term predictions and long-term projections about the AMOC-induced sea level rise along the eastern U.S. coast. The results would be valuable for the coastal communities and policy-makers to design sustainable coastal planning, and therefore are in line with NOAA’s missions (comprehensive ocean and coastal planning and management).