The Mediterranean region is experiencing pronounced aridification and in
certain areas higher occurrence of intense precipitation.
In this work, we analyze the evolution of the rainfall probability
distribution in terms of precipitating days (or “wet-days”) and
all-days quantile trends, in Europe and the Mediterranean, using the
Looking at the form of wet-days quantile trends curves, we identify four
Two are predominant: in most of Northern Europe the rainfall quantiles
all intensify, while in the Mediterranean the low-medium quantiles are
mostly decreasing as extremes intensify.
The wet-days distribution is then modeled by a Weibull law with two
parameters, whose changes capture the four regimes.
Assessing the significance of the parameter changes over 1950–2020
shows that a signal on wet-days distribution has already emerged in
Northern Europe (where the distribution shifts to more intense
rainfall), but not yet in the Mediterranean, where the natural
variability is stronger.
We extend the results by describing the all-days distribution change as
the wet-days’, plus a contribution from the dry-days frequency change,
and study their relative contribution.
In Northern Europe, the wet-days distribution change is the dominant
driver, and the contribution of dry-days frequency change can be
neglected for wet-days percentiles above about 50\%.
In the Mediterranean, however, the contribution to all-days change of
wet-days distribution change is much smaller than the one of dry-days
Therefore, in the Mediterranean the increase of dry-days frequency is
crucial for all-days trends, even when looking at heavy precipitations.