CR 22:147-159 (2002)  -  doi:10.3354/cr022147

ABSTRACT: This study investigates the variations of the cyclonic activity in the Mediterranean region that would be produced by doubling the CO₂ atmospheric content. The analysis is based on the SLP (sea-level pressure) fields produced by two 30 yr long time slice experiments of the ECHAM 4 model at T106 resolution, carried out by DMI, simulating the present and doubled CO₂ scenarios. The cyclonic activity in the Mediterranean region is similar in the 2 climate scenarios. The present climate is characterized with a slightly, but statistically significant, higher overall number of cyclones. The doubled CO₂ simulation is characterized with more extreme weather events, but the difference between the 2 scenarios is hardly significant. No variation in the regions of formation of the cyclones was clearly identified. An, admittedly small, number of cyclones of both scenarios was simulated using a limited area model (LAM) with 0.25° resolution. These simulations do not suggest that an increased model resolution should add new major findings to the results of this study, but the possibility that a climate change signal is not evident because of the coarse T106 model resolution remains open for further investigations. However, this study does not show a large change in the regime of the cyclones in the Mediterranean region due to the atmospheric CO₂ doubling.

KEY WORDS: Cyclones · Regional scenarios · Climate change · CO₂ doubling · Mediterranean region · Extreme events