Tracking cyclones in regional model data: the future of Mediterranean storms

摘要

With the advent of regional climate modelling, there arehigh-resolution data available for regional climatological changestudies.Automatic tracking of cyclones in these datasets encountersproblems with high spatial resolution dueto cyclone substructure. Watershed segmentation, a technique fromimage analysis, has been used to obtain estimates for the spatialextent of cyclones, enabling better tracking and precipitation analysis.In this study we have used data from a 0.5° Regional Model (REMO)climatologicalmodel run for the period from 1961-2099, following the InternationalPanel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) B2forcing. The resulting hourly mean sea level pressure (MSLP) fields have beenanalysed for cyclone numbers and tracks in the Mediterranean region.According to the results, the total number of cyclones in the Mediterranean seemsto be increasing in the future, in spite of a general decrease of thenumbers of stronger systems. In Summer, the increase in each gridboxseems to be proportional to the total number of cyclones in that box,whereas in Winter there is a slight proportionaldecrease. As concerns track properties and precipitation estimatesalong tracks, no significant change could be detected.