Supervisors info:
Τυρλής Ευάγγελος, Επίκουρος Καθηγητής, Τμήμα Φυσικής, ΕΚΠΑ
Summary:
This thesis aims to study the effect of large volcanic eruptions on the atmospheric circulation over the Eastern Mediterranean (EM) region during boreal summer. To this aim, we analyze data from climate model simulations from the Twentieth Century Reanalysis Project. Particularly, we have chosen to study the effects of one of the most influential volcanic eruptions, that of the Novarupta-Katmai volcano (South Alaska – 1912). The analysis involves the calculation of deviations from climatology for several selected atmospheric variables in a post volcanic eruption period.
The variables are studied at surface and isobaric levels of 850hPa, 500hPa, 200hPa, where monthly and weekly charts are examined for the summer period of 1912 and 1913, years with the strongest impact of the great volcanic eruption. During these summers, the minimum in the frequency of the Etesians was recorded for the entire 20th century. The high-pressure system over Europe and low-pressure system over the Middle East, which usually combine to provide a strong pressure gradient over the EM, appeared significantly weakened. Significant cooling over the EM was observed at low and mid-tropospheric levels, especially for 1913 when the volcanic impact intensified. In contrast, warming was observed in the upper troposphere and lower stratosphere.
Keywords:
Eastern Mediterranean, Etesians, Large Volcanic Eruption, climatology
