182
Murat Tiirke~
1 Introduction
Increased frequencies and intensities of the drier conditions in about last twenty-five
years may have been related to dominance of the anticyclonic circulation during the
same time period, due to mainly increased atmospheric geopotential heights and
decreased cyclone activity over the Turkey region (Tiirke~, 1998a). Furthermore,
various climate models predict a decrease in precipitation for future changes over
many parts of sUbtropics including eastern Mediterranean Basin and Turkey,
particularly in the winter or generally during cool part of the year (ECSN, 1995;
UKMO, 1995; lacobeit, 1996; UKMOIDETR, 1999). In addition to the long-lasting
summer dryness of the Mediterranean type climate, considerable persistent dry
conditions during about last three decades and secular decreasing trends in the annual
and particularly in the winter precipitation totals make the natural and socio-economic
system of Turkey more vulnerable to the projected changes in the mean climate.
Projected changes in the climatic variability in addition to the mean climate and
changes in land use, which should be considered in the future especially with respect
to the land use management, regional planning, forestry and agricultural activities,
would also make the existing conditions progressively worse.
This presentation has been prepared mainly based on the author's previous
studies (Tiirke~, 1996a, 1996b, 1998a, 1998b and 1999) and on some new and
additional analyses, for the RICAMERA Workshop on the 'Development of a
concerted data assessment, assimilation and validation for "Global Change" research'
held at Casablanca - Morocco, February 21-24, 2001. The scope of the presentation
IS:
I. to give detail information on spatial distribution of mean precipitation totals,
precipitation variability and seasonality of precipitation, and to examine the arid
lands of Turkey by using an aridity index;
2. to evaluate the long-term variations including trend and persistence in normalized
precipitation and aridity index series, and periodicity in aridity index series of
Turkey, for the 1930-1993 period; and,
3. to analyse the spatial and temporal variations of normalized precipitation
anomalies, with respect to the dry (drier than normal) and wet (wetter than
normal) conditions for the 1994-2000 period over Turkey.
2 Data
The Turkish State Meteorological Service (TSMS) is responsible for the synoptic
(weather and upper air), climatological and marine meteorological observations, and
the weather and sea forecasts and warnings in Turkey. Aims and activities of the
TSMS can be summarized as follows: to open and operate all kinds of meteorological
stations or units over Turkey; to make various observations and weather forecasts for
all users and sectors; to support particularly to the sectors of agriculture, forest,
tourism, transport, energy, health and armed forces; to broadcast weather and sea
forecasts and warnings; and to make researches to describe and understand Turkey's
Murat Tiirke~
1 Introduction
Increased frequencies and intensities of the drier conditions in about last twenty-five
years may have been related to dominance of the anticyclonic circulation during the
same time period, due to mainly increased atmospheric geopotential heights and
decreased cyclone activity over the Turkey region (Tiirke~, 1998a). Furthermore,
various climate models predict a decrease in precipitation for future changes over
many parts of sUbtropics including eastern Mediterranean Basin and Turkey,
particularly in the winter or generally during cool part of the year (ECSN, 1995;
UKMO, 1995; lacobeit, 1996; UKMOIDETR, 1999). In addition to the long-lasting
summer dryness of the Mediterranean type climate, considerable persistent dry
conditions during about last three decades and secular decreasing trends in the annual
and particularly in the winter precipitation totals make the natural and socio-economic
system of Turkey more vulnerable to the projected changes in the mean climate.
Projected changes in the climatic variability in addition to the mean climate and
changes in land use, which should be considered in the future especially with respect
to the land use management, regional planning, forestry and agricultural activities,
would also make the existing conditions progressively worse.
This presentation has been prepared mainly based on the author's previous
studies (Tiirke~, 1996a, 1996b, 1998a, 1998b and 1999) and on some new and
additional analyses, for the RICAMERA Workshop on the 'Development of a
concerted data assessment, assimilation and validation for "Global Change" research'
held at Casablanca - Morocco, February 21-24, 2001. The scope of the presentation
IS:
I. to give detail information on spatial distribution of mean precipitation totals,
precipitation variability and seasonality of precipitation, and to examine the arid
lands of Turkey by using an aridity index;
2. to evaluate the long-term variations including trend and persistence in normalized
precipitation and aridity index series, and periodicity in aridity index series of
Turkey, for the 1930-1993 period; and,
3. to analyse the spatial and temporal variations of normalized precipitation
anomalies, with respect to the dry (drier than normal) and wet (wetter than
normal) conditions for the 1994-2000 period over Turkey.
2 Data
The Turkish State Meteorological Service (TSMS) is responsible for the synoptic
(weather and upper air), climatological and marine meteorological observations, and
the weather and sea forecasts and warnings in Turkey. Aims and activities of the
TSMS can be summarized as follows: to open and operate all kinds of meteorological
stations or units over Turkey; to make various observations and weather forecasts for
all users and sectors; to support particularly to the sectors of agriculture, forest,
tourism, transport, energy, health and armed forces; to broadcast weather and sea
forecasts and warnings; and to make researches to describe and understand Turkey's