Multi-decadal sea-level changes from saltmarsh indicators and tide gauges

Estimates of mean sea-level changes at multi-decadal time scales rely on coastal tide gauge records that provide accurate measurements of relative sea level (RSL) with high temporal sampling. Despite most of the world coastlines are nowadays monitored by tide gauges, only a small subset of records spans more than 100 years, limiting our ability to quantify long-term mean sea-level changes and to unravel the underlying forcing mechanisms. In contrast, saltmarsh sediments record RSL during the last few hundred years with a decimetre accuracy and varying temporal resolution. We propose to consistently combine these two complementary sources of observations, taking advantage of the more accurate tide gauge measurements and longer saltmarsh time spans. Preliminary results on extended RSL records will be shown in this presentation and will be used to explore multi-decadal mean sea-level variability at the regional scale.