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Ocean waves and storm surges in the Adriatic Sea: intercomparison
between the present and doubled CO2 climate scenariosProgress
in coupled meteo-oceanic predictions in the mediterranean region
Lionello P., A. Nizzero, E. Elvini
This study attemps to estimate the effect of the CO2 doubling
on the frequency and intensity of high wind waves and storm surge
events in the Adriatic Sea. The meteorological forcings have been
derived from two 30-year long time slice experiments, that simulate
the global atmospheric circulation in the present and the doubled
CO2 climate scenarios. These time slice experiments
were carried out by DMI using the ECHAM-4 model at T106 resolution.
Unfortunately, the resolution of the T106 wind is inadequate for
the simulation of the wave field and the storm surge in the Adriatic
Sea, and it results in a huge underevaluation of the extreme events.
In this study, the regional surface wind fields have been derived
from the T106 sea level pressure fields by statistical downscaling.
The downscaled wind fields have been used to force a wave and
a ocean model during the two 30-year long simulations of the present
and doubled CO2 climate scenarios.
The downscaled wind fields produce a large improvement with respect
to the T106 fields, but a systematic underestimation with respect
to the observed wave height and surge levels remains present.
This shortcoming of the analysis might prevent the identification
of very high events.
Consequently, the extreme value analysis of the results of the
present climate simulation produces values lower than observed,
and obviously, the same systematic bias is expected in the evaluation
of the future climate.
Some caution is therefore necessary in the interpretation of the
results of this study.
Anyway, the comparison between the present and future climate
simulations, shows no substantial variation in the extreme surge
level and a decrease of the extreme wave height.
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