Walker - 1967 - A geography of Italy

CLIM ATE
further south) and there are two rainy
periods, one in autiunn and the other
either in spring (mainly in the north and
the interior) or in winter (mainly on the
coastlands further south).
The significance o f mean annual rainfall
figures for stations in Italy should be
assessed with caution. Both in England
and Italy they vary from about 500 mm
in the driest areas to about 2000 mm in
the wettest, but such a crude comparison
masks a contrast in the effectiveness of
the rainfall from the farmer’s point of
view. Firstly, the rainfall in Italy is obviously
much more seasonal in character.
This is not necessarily a misfortune. In
fact, the greater incidence in the cool
season is most opportune; the same totals
distributed throughout the year would
serve only to increase the proportion
of moisture lost by evaporation in the
summer and to soak the subsoil less
thoroughly in winter. Secondly, the rainfall
in Italy occurs more frequently than
in England in the form o f short, heavy
showers which are conducive to soil
erosion and are particularly destructive
when accompanied by hail, as is often
the case with convectional storms and
with cold front distiurbances. Furthermore,
such brief rainy spells merely
punctuate much longer periods o f strong
insolation and intense evaporation.
Thirdly, Italy’s rainfall is unreliable
both in its seasonal incidence and in the
annual totals received. For example, Milan
received 466 mm in 96 days in 1921,
and 1782 mm in n o days in 1951; for
the same years the totals for the three
I E HI iz I3Z I2ninrnxm u -too
BORMIO
7 2 8 mm.
TAORMINA
7 3 2 mm.
- 50
■100
- 5 0
-100
- 50
-100
■50
Fig. II. Seasonal distribution of rainfall in
millimetres for Bormio (type i onfig. i2),Milan
(type 2), Rome (type 3) and Taormina (type 4)
57