Spatial and Temporal Variations in Precipitation
and Aridity Index Series of Turkey
M. Tiirke~
Abstract
Annual and seasonal precipitation series and annual aridity index series of
Turkey were investigated with respect to spatial and temporal variations for
the period 1930-1993. Analysis of normalized precipitation anomalies was
also performed for the 1994-2000 period. Semi-arid and dry sub-humid
climatic conditions are dominant over the continental interiors and
continental Mediterranean region of Turkey. Normalized annual and winter
precipitation series have tended to decrease over a considerable part of
Turkey since the early 1970s. For the normalized annual and winter
precipitation anomaly series, wet conditions generally occurred during the
1940s, 1960s, late 1970s, early 1980s and mid-late 1990s, whereas dry
conditions generally dominated over the early-mid 1930s, early-mid 1970s,
mid-late 1980s, early 1990s, and 1999/2000 in most of Turkey. Spring
precipitation series generally indicated an upward trend from the mid 1940s
to the late 1960s at many stations and to 1980s at some stations. This period
was generally followed by a downward trend at many stations. Significant
decreasing trends showed up in the annual precipitation series of 15 stations
and in the winter precipitation series of 14 stations, mostly over the
Mediterranean rainfall region. Summer rainfall series have tended to increase
significantly at 7 stations. There has also been a general tendency from
humid conditions of around the 1960s towards dry sub-humid climatic
conditions in the aridity index values of many stations of Turkey. At some
stations over the Aegean part of the Mediterranean region, there has been a
significant change from humid conditions to dry sub-humid or semi-arid
climatic conditions.
Key Words: Turkey, Precipitation, Aridity Index, Seasonality, Variability,
Trend and Persistent.
and Aridity Index Series of Turkey
M. Tiirke~
Abstract
Annual and seasonal precipitation series and annual aridity index series of
Turkey were investigated with respect to spatial and temporal variations for
the period 1930-1993. Analysis of normalized precipitation anomalies was
also performed for the 1994-2000 period. Semi-arid and dry sub-humid
climatic conditions are dominant over the continental interiors and
continental Mediterranean region of Turkey. Normalized annual and winter
precipitation series have tended to decrease over a considerable part of
Turkey since the early 1970s. For the normalized annual and winter
precipitation anomaly series, wet conditions generally occurred during the
1940s, 1960s, late 1970s, early 1980s and mid-late 1990s, whereas dry
conditions generally dominated over the early-mid 1930s, early-mid 1970s,
mid-late 1980s, early 1990s, and 1999/2000 in most of Turkey. Spring
precipitation series generally indicated an upward trend from the mid 1940s
to the late 1960s at many stations and to 1980s at some stations. This period
was generally followed by a downward trend at many stations. Significant
decreasing trends showed up in the annual precipitation series of 15 stations
and in the winter precipitation series of 14 stations, mostly over the
Mediterranean rainfall region. Summer rainfall series have tended to increase
significantly at 7 stations. There has also been a general tendency from
humid conditions of around the 1960s towards dry sub-humid climatic
conditions in the aridity index values of many stations of Turkey. At some
stations over the Aegean part of the Mediterranean region, there has been a
significant change from humid conditions to dry sub-humid or semi-arid
climatic conditions.
Key Words: Turkey, Precipitation, Aridity Index, Seasonality, Variability,
Trend and Persistent.