The Mediterranean storm track constitutes a well-defined branch of the North
Hemisphere storm track and is characterised by small but intense features and
frequent cyclogenesis. The goal of this study is to assess the level of
consensus among cyclone detection and tracking methods (CDTMs), to identify
robust features and to explore sources of disagreement. A set of 14 CDTMs has
been applied for computing the climatology of cyclones crossing the
Mediterranean region using the ERA-Interim dataset for the period 1979–2008 as
common testbed. Results show large differences in actual cyclone numbers
identified by different methods, but a good level of consensus on the
interpretation of results regarding location, annual cycle and trends of
cyclone tracks. Cyclogenesis areas such as the north-western Mediterranean,
North Africa, north shore of the Levantine basin, as well as the seasonality
of their maxima are robust features on which methods show a substantial
agreement. Differences among methods are greatly reduced if cyclone numbers
are transformed to a dimensionless index, which, in spite of disagreement on
mean values and interannual variances of cyclone numbers, reveals a consensus
on variability, sign and significance of trends. Further, excluding ‘weak’ and
‘slow’ cyclones from the computation of cyclone statistics improves the
agreement among CDTMs. Results show significant negative trends of cyclone
frequency in spring and positive trends in summer, whose contrasting effects
compensate each other at annual scale, so that there is no significant long-
term trend in total cyclone numbers in the Mediterranean basin in the
1979–2008 period
