Circulation Types and Their Influence on the Interannual Variability
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between the atmospheric circulation and the rainfall in Greece, namely the
interannual variability, as well as any long-term trends and extremes.
2 The Spatial Distribution of Precipitation in Greece
In order to study the spatial distribution of precipitation in Greece, daily and monthly
precipitation data from 20 stations distributed evenly over Greece (Fig. 1) was used
that covers a 40-years period from January 1958 to December 1997.
Kriging interpolation methods were employed to describe the spatial patterns of
precipitation. It should be noted that the interpolated values based on the Kriging
methods, over the mountainous regions as well as over the Eastern Aegean Sea and
western Turkey are less certain because there are no stations in these areas and thus,
should be considered with caution. This should be kept in mind for all the following
maps in this study.
Meridional Aegean Sea (Cyclades) has long been recognised as the driest region
in Greece (Fig. 2). Of more practical importance is the fact that in many parts of the
region the annual average rainfall does not exceed the 400 mm. In contrast, the Ionian
Island and western Greece reveals a remarkable maximum of more than 900 mm per
year. Precipitation is unevenly distributed throughout seasons with the winter being
the rainiest season. During winter the spatial distribution of rainfall amount (Fig.3)
42,,~----------------------------------------,
40-1
t38 l
37 1
36
35
r
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Fig. 2. Geographical distribution of annual precipitation amounts in mm/year