Dynamic Sea-Level Simulation for Southeast Asia in the CMIP6 HighResMIP models: Mean biases and Changes by the end of the 21st Century

TitleDynamic Sea-Level Simulation for Southeast Asia in the CMIP6 HighResMIP models: Mean biases and Changes by the end of the 21st Century
Publication TypeConference Paper
Year of Publication2020
AuthorsSamanta D, Jevrejeva S, Karnauskas KB, Goodkin N, Horton BP
Conference NameAmerican Geophysical Union Fall Meeting
Date Published12/2020
Conference LocationOnline
Abstract

Southeast Asia consists of several low-lying small islands, highly populated coastal cities, and extensive coastal ecosystems, and therefore is extremely vulnerable to the impacts of future sea-level rise. The contribution of ocean dynamic to future sea-level rise across Southeast Asia remains highly uncertain because of the coarse horizontal model resolutions (~100 km or lower). Here, we use the latest High-Resolution Model Intercomparison Project (HighResMIP) of the Coupled Model Intercomparison Project Phase 6 (CMIP6) to study the present and future dynamic sea-level. We chose HighResMIP models that included a historical period and at least shared socioeconomic pathways (SSP) 5-8.5 future scenario. The higher horizontal resolution (up to 25 km) of HighResMIP models better simulates the distribution of heat, salt, and mass in the ocean, which reflects in the dynamical sea-level simulation. We examine: (1) the mean biases of dynamic sea-level of these HighResMIP models with observations during the satellite era and noted a significant improvement over the low-resolution models; and (2) the changes in ocean dynamic sea-level by the end of 21st century for SSP5-8.5, SSP3-7.0, and SSP2-4.5 scenarios. Despite intermodel diversity in the possible changes in dynamic sea-level change, there is an overall agreement in the spatial pattern and rise across the region. For example, we suggest a significant rise in dynamic sea-level along the coast of Southeast Asia of ~ 0.2 m under SSP5-8.5 by 2100. Adding the thermosteric component to this dynamic sea-level results in a further rise of ~0.3 m by the end of the 21st century (~0.5 m in total). The dynamic sea-level simulations for Southeast Asia provide an insight into their contribution to future sea-level and will be instrumental for further ocean modelling studies.