Cause of substantial global mean sea level rise over 2014-2016
Event: 2023 Ocean Surface Topography Science Team Meeting
Session: Synergies between Argo, GRACE and Altimetry
Presentation type: Type Oral
Contribution: PDF file
Global mean sea level rise is one of the direct consequences of the actual global warming. This rise has been monitored for years by satellite altimetry missions which provide high quality data at nearly global coverage. This global rise is caused by global ocean warming (known as thermosteric sea level) and the continental freshwater discharge from land ice melting (i.e., Greenland and Antarctica ice sheets and mountain glaciers; known as barystatic sea level). On top of the background sea level trend, large interannual variability can occur which can be attributed to natural climate mode of variability (such as ENSO, PDO, etc). Since 2005 and at global scale, ocean warming and barystatic sea level can be assessed by complementary observing systems such as Argo profiles and GRACE/GRACE-FO data, respectively. In this study, we investigate the extreme El Nino events occurring in 2014-2016 and their imprints on the global mean sea level change by assessing all the different components of the sea level budget. Over 2014-2016, we find that the global mean sea level experiences a rise of 1.5 cm over 24 months. 20% of this rise can be attributed to global ocean warming and 80% to barystatic sea level rise. Half of the barystatic sea level rise can be attributed to terrestrial water changes in South America with a significant contribution from the Amazon basin (5mm).