The Sea Level Acceleration and its Observation from Tide Gauces

Tide gauges form a unique data set of sea-level observations that covers the last 200 years and more. Based on these data, models of the sea-level change have been created with the aim of assessing the global rate of sea-level rise and its acceleration. Such global models play a crucial role for the understanding of the ongoing climate change but these are also the roots for realistic scenarios of future sea level. Unfortunately, the sparse distribution of the tide gauge sites and the presence of long period oscillations pose some limitations that could compromise the reliability of the results. In this dissertation I discuss the limits of using tide gauges data for the assessment of sea-level rise, with a focus on sea-level acceleration. The results confirm that long period oscillations, if not properly modeled, can bias the rate and the acceleration. Moreover, the limited number of observation points confined at coastlines can further disrupt the veracity of models. These findings are used to establish a new and more robust description of the century scale global mean sea level.