Beschreibung:
<jats:p>Abstract. Projections of sea level rise (SLR) will lead to increasing coastal impacts
during extreme sea level events globally; however, there is significant
uncertainty around short-term coastal sea level variability and the attendant
frequency and severity of extreme sea level events. In this study, we
investigate drivers of coastal sea level variability (including extremes)
around Australia by means of historical conditions as well as future changes
under a high greenhouse gas emissions scenario (RCP 8.5). To do this, a
multi-decade hindcast simulation is validated against tide gauge data. The
role of tide–surge interaction is assessed and found to have negligible
effects on storm surge characteristic heights over most of the coastline. For
future projections, 20-year-long simulations are carried out over the
time periods 1981–1999 and 2081–2099 using atmospheric forcing from four
CMIP5 climate models. Changes in extreme sea levels are apparent, but there
are large inter-model differences. On the southern mainland coast all models
simulated a southward movement of the subtropical ridge which led to a small
reduction in sea level extremes in the hydrodynamic simulations. Sea level
changes over the Gulf of Carpentaria in the north are largest and positive
during austral summer in two out of the four models. In these models, changes to
the northwest monsoon appear to be the cause of the sea level response. These
simulations highlight a sensitivity of this semi-enclosed gulf to changes in
large-scale dynamics in this region and indicate that further assessment of
the potential changes to the northwest monsoon in a larger multi-model
ensemble should be investigated, together with the northwest monsoon's effect on extreme sea levels.
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