CoAuthors

Ben Hamlington (NASA Jet Propulsion Laboratory, USA); Steve Nerem (University of Colorado Boulder, United States); Thomas Frederikse (NASA Jet Propulsion Laboratory, USA)

It is well known that regional sea level is influenced by multiple processes operating on a range of timescales. Separating the relative contributions of each of these processes has important implications for our ability to understand both contemporary and future sea level change. With available observations, it is now possible to conduct sea level budget studies--similar to those done on global scales--on a regional level. Here, we focus on the time period from 1993 to present, starting from trends measured by satellite altimeters and tide gauges and then quantifying the contributions from relevant processes. We show that after identifying steric expansion, mass redistribution, large-scale ocean dynamics, GIA, and localized land motion as the major components of relative regional sea level change, extended observations of each component allow for budget closure within bounds of uncertainty. To account for relative sea level change measured by tide gauges, co-located GPS stations provide rates of vertical land motion which are primarily influenced by GIA in addition to more localized uplift due to mass redistribution. Comparisons between regional relative sea level from tide gauges and open ocean altimetry as well as steric measurements provide the foundation for the ocean dynamics and steric components of the budget, respectively. The results of this study highlight the advancements in the understanding that can be obtained regarding regional sea level variability as a result of the improved observational network that is available over the past decades.