Skip to main content
U.S. flag

An official website of the United States government

Gravitational and solid-Earth deformation response to ocean dynamic loading amplifies local sea-level change

Presentation Date
Friday, December 15, 2023 at 2:10pm - Friday, December 15, 2023 at 6:30pm
MC - Poster Hall A-C - South



Ocean dynamic sea level (DSL) is the deviation of sea surface height from the geoid due to ocean dynamics, and changes in DSL is an important component of spatial variations in sea-level change. Future DSL changes are typically predicted using the ocean model component of climate models forced by greenhouse gas emissions scenarios into the future, for example following pathways prescribed by the Coupled Model Intercomparison Project (CMIP). However, most climate and global ocean models do not include gravitational, rotational, and deformation (GRD) effects of the solid Earth which modify relative sea level as mass is redistributed around the surface of the Earth. GRD effects have commonly been applied to predicting regional sea level originating from land ice mass change but have been applied less to other contributors to sea-level change. Here we use a 1-d viscoelastic sea-level/GRD model to calculate the GRD response to the mass loading caused by changes in DSL, using ocean model projections of DSL through 2100 from the CMIP archive. We find that the GRD response to DSL typically adds an additional 10-20% sea-level change to DSL changes, with most of that effect coming from changes in self-gravitation, followed by elastic adjustment of the lithosphere. However, significant deviations from this typical amplification occur due to the differing spatial scales of DSL changes and GRD effects, as well as the influence of rotational effects. We identify how GRD effects are conceptually similar to the self-attraction and loading term accounted for in tidal models. For ocean models excluding such calculations, the GRD response to DSL changes should be subsequently calculated to avoid an underestimation of ~15% in the sea-level change associated with DSL.

Funding Program Area(s)