Detecting a forced signal in satellite-era sea-level change

• Published in: Environmental Research Letters
• Main Authors: Richter, K., Meyssignac, B., Slangen, A., Melet, A., Church, J., Fettweis, Xavier, Marzeion, B., Agosta, Cécile, Ligtenberg, S., Spada, G., Palmer, M., Roberts, C., Champollion, N.
• Other Authors: Sphères - SPHERES
• Format: Article in Journal/Newspaper
• Language: English
• Published: Institute of Physics Publishing 2020
• Subjects: Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Ice Sheet
• Online Access: https://orbi.uliege.be/handle/2268/248321; https://orbi.uliege.be/bitstream/2268/248321/1/Richter%2bet%2bal_2020_Environ._Res._Lett._10.1088_1748-9326_ab986e.pdf; https://doi.org/10.1088/1748-9326/ab986e

peer reviewed In this study, we compare the spatial patterns of simulated geocentric sea-level change to observations from satellite altimetry over the period 1993-2015 to assess whether a forced signal is detectable. This is challenging, as on these time scales internal variability plays an important role and may dominate the observed spatial patterns of regional sea-level change. Model simulations of regional sea-level change associated with sterodynamic sea level, atmospheric loading, glacier mass change, and ice-sheet surface mass balance changes are combined with observations of groundwater depletion, reservoir storage, and dynamic ice-sheet mass changes. The resulting total geocentric regional sea-level change is then compared to independent measurements from satellite altimeter observations. The detectability of the climate-forced signal is assessed by comparing the model ensemble mean of the "historical" simulations with the characteristics of sea-level variability in pre-industrial control simulations. To further minimize the impact of internal variability, zonal averages were produced. We find that, in all ocean basins, zonally averaged simulated sea-level changes are consistent with observations within sampling uncertainties associated with simulated internal variability of the sterodynamic component. Furthermore, the simulated zonally averaged sea-level change cannot be explained by internal variability alone - thus we conclude that the observations include a forced contribution that is detectable at basin scales.