210
Murat Tiirke~
In 1999, a well-defined coherent region characterized with below normal and
much below normal precipitation conditions appeared over the southern half of Turkey
(Fig. 15c). Drier than normal precipitation conditions affected the Continental Eastern
Anatolia and Continental Mediterranean regions again. In this year, drier than and/or
near normal precipitation conditions were experienced almost in all months over most
of Turkey, except north-western parts.
In the year 2000, drier than normal precipitation conditions were evident over the
western regions of Turkey and persisted over the Continental Eastern Anatolia and
Continental Mediterranean regions (Fig. 15d). Much below normal precipitation
anomalies showed a spatial coherence over the Continental Eastern Anatolia and
Continental Mediterranean regions. Monthly assessment of the precipitation anomalies
indicated that drier than normal conditions generally dominated throughout the year
2000 over most of Turkey, except the Black Sea, eastern part of the Marmara and
Continental Central Anatolia. During the four-month period between October of 2000
and January of 2001, areas having below than normal precipitation covered most of
Turkey.
5 Discussion and Conclusions
Dry sub-humid climatic conditions extend over most of the Continental Central
Anatolia and Continental Mediterranean regions, some parts of the eastern
Mediterranean, and some parts of the Continental Eastern Anatolia region. Semi-arid
climatic conditions are dominant over the Konya sub-region of the Central Anatolia,
and over the eastern margin of the Eastern Anatolia region. In the arid lands of
Turkey, coefficients of variation are generally above 20 per cent annually and 30 per
cent in winter and spring, and above 45-50 per cent in autumn and summer.
Characteristic vegetation formations of semi-arid and dry sub-humid regions of
Turkey are generally steppe and steppe with sparse trees, and steppe with trees and dry
forests, respectively (Atalay, 1994). Anthropogenic steppes with dry forests are the
dominant vegetation formations over the semi-arid and dry sub-humid parts of the
Continental Eastern Anatolia region. These sparse vegetation covers protect and
stabilize the land surface and soil, except where the land is completely degraded, and
when climatic changes result in significant increase of aridity conditions, or decrease
of precipitation amounts, and water resources.
For the period 1930-1993, wet conditions in the annual and winter precipitation
series generally occurred during the 1940s, 1960s, late 1970s and early 1980s, whereas
dry conditions generally dominated over the early-mid 1930s, early-mid 1970s, midlate 1980s and early 1990s over most of Turkey. When the 1970-1993 period was
taken into account, it was found that severe and widespread dry conditions occurred
especially in the years of 1973, 1977, 1984, 1989 and 1990 (Tiirke~, 1996b).
Spring precipitation series of many stations generally indicated an upward trend
from the early 1940s to the late 1960s or to the 1980s and this period was generally
followed by a downward trend. The longer runs of dry anomalies were dominant
characteristics of the summer. Autumn precipitation series generally show a random
run of anomalies mostly with a stable mean at many stations, along with a some
Murat Tiirke~
In 1999, a well-defined coherent region characterized with below normal and
much below normal precipitation conditions appeared over the southern half of Turkey
(Fig. 15c). Drier than normal precipitation conditions affected the Continental Eastern
Anatolia and Continental Mediterranean regions again. In this year, drier than and/or
near normal precipitation conditions were experienced almost in all months over most
of Turkey, except north-western parts.
In the year 2000, drier than normal precipitation conditions were evident over the
western regions of Turkey and persisted over the Continental Eastern Anatolia and
Continental Mediterranean regions (Fig. 15d). Much below normal precipitation
anomalies showed a spatial coherence over the Continental Eastern Anatolia and
Continental Mediterranean regions. Monthly assessment of the precipitation anomalies
indicated that drier than normal conditions generally dominated throughout the year
2000 over most of Turkey, except the Black Sea, eastern part of the Marmara and
Continental Central Anatolia. During the four-month period between October of 2000
and January of 2001, areas having below than normal precipitation covered most of
Turkey.
5 Discussion and Conclusions
Dry sub-humid climatic conditions extend over most of the Continental Central
Anatolia and Continental Mediterranean regions, some parts of the eastern
Mediterranean, and some parts of the Continental Eastern Anatolia region. Semi-arid
climatic conditions are dominant over the Konya sub-region of the Central Anatolia,
and over the eastern margin of the Eastern Anatolia region. In the arid lands of
Turkey, coefficients of variation are generally above 20 per cent annually and 30 per
cent in winter and spring, and above 45-50 per cent in autumn and summer.
Characteristic vegetation formations of semi-arid and dry sub-humid regions of
Turkey are generally steppe and steppe with sparse trees, and steppe with trees and dry
forests, respectively (Atalay, 1994). Anthropogenic steppes with dry forests are the
dominant vegetation formations over the semi-arid and dry sub-humid parts of the
Continental Eastern Anatolia region. These sparse vegetation covers protect and
stabilize the land surface and soil, except where the land is completely degraded, and
when climatic changes result in significant increase of aridity conditions, or decrease
of precipitation amounts, and water resources.
For the period 1930-1993, wet conditions in the annual and winter precipitation
series generally occurred during the 1940s, 1960s, late 1970s and early 1980s, whereas
dry conditions generally dominated over the early-mid 1930s, early-mid 1970s, midlate 1980s and early 1990s over most of Turkey. When the 1970-1993 period was
taken into account, it was found that severe and widespread dry conditions occurred
especially in the years of 1973, 1977, 1984, 1989 and 1990 (Tiirke~, 1996b).
Spring precipitation series of many stations generally indicated an upward trend
from the early 1940s to the late 1960s or to the 1980s and this period was generally
followed by a downward trend. The longer runs of dry anomalies were dominant
characteristics of the summer. Autumn precipitation series generally show a random
run of anomalies mostly with a stable mean at many stations, along with a some