NEW EVIDENCE FOR THE ROLE OF THE NORTH SEA – CASPIAN PATTERN ON THE TEMPERATURE AND
NEW EVIDENCE FOR THE
ROLE OF THE NORTH SEA –
CASPIAN PATTERN ON THE TEMPERATURE
AND PRECIPITATION REGIMES IN
CONTINENTAL CENTRAL TURKEY
BY
H. KUTIEL 1 AND M. TÜRKE≠ 2
1 Department
2
of Geography and Environmental Studies, University of Haifa, Haifa, Israel
Department of Geography, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
Kutiel, H. and Türke≠, M., 2005: New evidences for the role of
the North Sea – Caspian Pattern on the temperature and precipitation regimes in continental central Turkey. Geogr. Ann., 87
A(4): 501–513.
ABSTRACT. Monthly mean temperatures and
monthly precipitation totals at six stations from the
Cappadocian sub-region in the continental Central
Anatolia region of Turkey were analysed in order to
detect the response of the variability in the Cappadocian climate to the variability of the North Sea –
Caspian Pattern Index (NCPI). Most of this region is
classified as semi-arid according to various climate
classifications. Time series of the NCPI for the period 1958–1998, enabled each month from October to
April to be classified as belonging to the negative
phase NCP(–), positive phase NCP(+) or neutral conditions. Monthly temperature and precipitation series for each station were analysed separately for
both phases. Temperatures during NCP(–) were
found to be considerably higher than during
NCP(+). These results confirm previous results regarding the role of the NCP in controlling the temperature regime in that region. No significant differences were found in precipitation totals between
the two phases, but major differences were identified in their spatial structure.
Key words: temperature, precipitation, NCP, composite correlation maps, Cappadocia, Turkey.
Introduction
The North Sea – Caspian Pattern (NCP hereafter), an atmospheric teleconnection between these
two regions at the 500 hPa geopotential height level, at a monthly timescale, was recently defined by
Kutiel and Benaroch (2002). Kutiel et al. (2002)
analysed the impacts of this teleconnection on the
temperature and precipitation regimes in the BalGeografiska Annaler · 87 A (2005) · 4
kans, the Anatolian Peninsula and the Middle East.
The North Sea – Caspian Pattern Index (NCPI)
was defined and calculated. This index measures
the normalized pressure differences between the
two poles of the teleconnection. Months with normalized values above 0.5 were defined as belonging to the positive phase; whereas months with values below –0.5 were defined as belonging to the
negative phase; all the rest were defined as neutral.
The positive phase is characterized by an increased
northeasterly anomaly-circulation while an increased southwesterly anomaly-circulation is observed during the negative phase (Kutiel and Benaroch 2002).
The impact of the NCP was found to be very
clear, mainly on the temperature regimes of all stations analysed in the eastern Mediterranean. The
NCPI differentiates between temperatures better
than any other circulation index such as the North
Atlantic Oscillation Index (NAOI) or the Southern Oscillation Index (SOI) (Kutiel et al. 2002).
This teleconnection, which is active mainly from
October to April (Kutiel and Benaroch 2002), has
a major influence on the temperature regime in the
Anatolian Peninsula and the Middle East, and to a
lesser extent on the precipitation regime in these regions.
The region where the greatest impact on the temperature regime was found is continental central
Turkey. The average temperature differences in that
region between the negative phase (the warm phase)
and the positive phase (the cold phase) was 3.4°C at
Ankara and 3.5°C at Erzurum for the seven-month
period from October to April (Kutiel and Benaroch
2002). In other stations in Turkey, smaller tempera501
H. KUTIEL AND M. TÜRKE≠
Table 1. Climate types in the Middle Kızılırmak (Cappadocian) sub-region according to various climate classifications (Türke≠ et al.
2004)
Station
Kır≠ehir
Kayseri
Ürgüp
Nev≠ehir
Aksaray
Ni¢de
Erinç Aridity
Index (Im)
21.55
21.15
22.71
25.73
18.54
19.46
Climate
type
Semi-arid
Semi-arid
Semi-arid
Semi-humid
Semi-arid
Semi-arid
Thornthwaite
Moisture
Index (Lm)
–22.6
–22.4
–20.0
–17.8
–27.9
–26.2
ture differences between the two phases were found.
Even at Mu¢la, where the smallest temperature difference between the two phases was observed
(2.0°C), this is far greater than any temperature difference in that region attributed to the two phases of
the NAO or the SO (Kutiel et al. 2002).
The role of the NCP on the precipitation regime
in Turkey, is more complex. In southwestern Turkey, more abundant precipitation are associated
with NCP (–), whereas in northeastern Turkey the
opposite is true. As this region of central Turkey lies
in the transition between the two, therefore, we do
not expect to find large differences in the precipitation totals between the two phases. We do expect,
however, differences in the spatial characteristics
of precipitation associated with one or other phase
of the NCP.
The purposes of the present study are to focus on
the impacts of the NCP variability on the temperature and precipitation regimes for the Middle
Kızılırmak sub-region of continental Central
Anatolia (CAN hereafter) region in Turkey, in order to strengthen the postulation in Kutiel et al.
(2002) regarding the role of the NCP on these regimes in that part of the world.
Physical geography of the study area
Climate types
Climate types of the Cappadocian sub-region were
determined by three climate classifications (Türke≠
et al. 2004; Table 1).
Elements of the climatic water budget or balance
that are needed for determination of the climate indices, except Erinç’s Aridity Index (Im), were calculated for six stations by the approach used in the
WATBUG program, which was developed by Willmott (1977) for climatic water budgets. Monthly elements of the water budget required for making the
climatic classifications of the study area include: potential evapotranspiration (PE, in mm), which is ad502
Climate
type
Semi-arid
Semi-arid
Dry sub-humid
Dry sub-humid
Semi-arid
Semi-arid
UNCCD Aridity
Index (AI)
0.55
0.57
0.60
0.63
0.49
0.50
Climate
type
Dry sub-humid
Dry sub-humid
Dry sub-humid
Dry sub-humid
Semi-arid
Dry sub-humid
justed for length of day and number of days in
month; precipitation minus potential evapotranspiration (P–PE, in mm); change in soil water or moisture storage from preceding month (CST, in mm);
actual evapotranspiration (AE, in mm), which is
equal to the PE when water storage is at field capacity or P–PE has a positive value, and otherwise equal
to the sum of P and CST; soil moisture deficit (D, in
mm), which is equal to PE-AE; and soil moisture
surplus (S, in mm), which is equal to the positive P–
PE when water storage is at its capacity or higher.
Thornthwaite’s Moisture Index (Lm) (Thornthwaite
1948), is calculated as follows:
where S is the annual water surplus and D the deficit
(mm); PE is the annual potential evapotranspiration (mm). Annual water surplus and deficit are determined by summation of monthly surplus and
deficit amounts, respectively. Annual PE also
equals to the sum of adjusted monthly PE amounts.
Erinç’s Aridity Index (precipitation efficiency) (Im)
(Erinç 1965 is based on the precipitation and the
maximum temperature that causes the water deficiency by evaporation. The basic equation of Im is
defined as follows:
–
–
where P and T max equal the long-term average of
the annual precipitation total (mm) and of annual
maximum temperature (°C) respectively. Erinç
(1965) divided his index into six major classes by
comparing the results of the index with the spatial
distribution of vegetation formations over Turkey as
in Table 2.
Geografiska Annaler · 87 A (2005) · 4
ROLE OF NCP ON CLIMATE IN TURKEY
Table 2. Climate types corresponding to the Erinç Aridity Index (Im) and vegetation types (Türke≠
et al. 2004) according to Erinç (1965)
Im
Climate type
Vegetation type
<8
8–15
15–23
23–40
40–55
>55
Severe arid
Arid
Semi-arid
Semi-humid
Humid
Perhumid
Desert
Desert-like steppe
Steppe
Dry forest
Humid forest
Perhumid forest
For the purposes of the United Nations Convention to Combat Desertification (UNCCD),
arid, semi-arid and dry sub-humid climates were
defined as ‘areas, other than polar and sub-polar regions, in which the ratio of annual precipitation to
potential evapotranspiration falls within the range
from 0.05 to 0.65’ (UNCCD 1995). Following the
United Nations Environmental Programme
(UNEP 1993), an aridity index AI is defined as:
AI = P / PE
where P and PE are the annual precipitation and
potential evapotranspiration (mm) totals, respectively.
According to the Thornthwaite Moisture Index
(Thornthwaite 1948), semi-arid and dry sub-humid climate types are dominant over the sub-region (Table 1). Dry sub-humid climatic conditions
are concentrated only over the Nev≠ehir–Ürgüp
province. The Erinç Aridity Index (Im) depicts
similar climatic conditions to with Lm: semi-arid
and semi-humid climate types prevail over the
sub-region (Table 1). Semi-humid climate is concentrated only over the Nev≠ehir–Ürgüp province,
which is a very similar spatial pattern to with the
dry sub-humid climatic of the Thornthwaite Moisture Index over the same province. The AI produces more humid climatic conditions for Cappadocia
than the other two climate indices. Dry sub-humid
climate type is dominant at all stations except at
Aksaray in the south (Table 1). Dry sub-humid climatic conditions exhibit a large spatial coherence
over the sub-region except the semi-arid area that
covers the southwestern part of the Aksaray and
Ni¢de provinces.
Vegetation cover
Under the present semi-arid and dry sub-humid climate conditions, steppe is the dominant vegetation
Geografiska Annaler · 87 A (2005) · 4
type in Cappadocia with some dry forests. According to Atalay’s (2002) study, in which he classified
the ecological regions of Turkey, the Cappadocian
sub-region is located in the ‘dry forest/anthropogenic steppe sub-region’ of the CAN region. Oaks,
black pine and Scots pine were the main trees of the
region (Atalay 2002). However, major parts of
these forests have been cleared; only some small
forested areas are found on the slopes facing north.
The steppe formation is widespread on the destroyed dry forest areas. Mountain grass formation
is only found on the mountainous areas rising over
2000 m in the sub-region.
Data and methodology
We used two basic data sets for this study: (1) mean
monthly temperatures (°C) and monthly precipitation totals (mm) recorded by the Turkish State
Meteorological Service (TSMS), at six stations in
the Middle Kizilirmak sub-region (i.e. Cappadocia) during the same period (Tables 3 and 4); and
(2) the calendar of the NCP monthly phases for the
period 1958–1998 (Table 5, adapted after Kutiel
and Benaroch 2002). Detailed information for the
meta-data and the homogeneity analyses applied to
long-term precipitation and temperature series of
Turkey can be found in Türke≠ (1996, 1999) and in
Türke≠ et al. (2002). The location of the six stations
in the Middle Kizilirmak sub-region is shown in
Fig. 1.
For each station in each month, the averages of
the mean temperatures and the precipitation totals
were calculated separately for all cases defined as
NCP (–) or NCP (+), based on the calendar published by Kutiel and Benaroch (2002) in the same
way as done in Kutiel et al. (2002).
However as we expect also differences in the
spatial distribution of the precipitation, we prepared and analysed composite correlation maps
(CCM hereafter) of monthly totals. CCM were
503
H. KUTIEL AND M. TÜRKE≠
Table 3. Information on the six stations of the Middle Kızılırmak (Cappadocian) sub-region chosen for the present study
Station ID
Station
Kır≠ehir
Kayseri
Ürgüp
Nev≠ehir
Aksaray
Ni¢de
Station
Record period
Number
Longitude
Latitude
height (m)
Precipitation
Temperature
17160
17196
17835
17193
17192
17250
34°09'
35°29'
34°55'
34°42'
34°03'
34°41'
39°10'
38°45'
38°38'
38°37'
38°23'
37°58'
1007
1093
1060
1260
961
1211
1958–1998
1958–1998
1963–1998
1958–1998
1958–1998
1958–1998
1958–1998
1958–1998
1970–1998
1960–1998
1964–1998
1958–1998
Table 4. Long-term averages and standard deviations (STD) of monthly and annual mean temperatures (°C) at the six stations of the Middle
Kızılırmak (Cappadocian) sub-region, along with the standard errors (SE) at the 95% confidence level. These average mean temperatures were
used for determination of the climate types in the study area according to Thornthwaite’s classification and UNCCD Aridity Index
Months
Parameters
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
Annual
Kır≠ehir (1930–2002)
Average (°C)
STD (°C)
SE (°C)
–0.39
2.88
0.66
1.21
2.91
0.67
5.03
2.27
0.52
10.60 15.32
1.65 1.16
0.38 0.27
19.50
0.99
0.23
22.91
1.18
0.27
22.58
1.23
0.28
17.97
1.43
0.33
12.16
1.65
0.38
6.26
1.78
0.41
1.93
2.53
0.58
11.26
0.74
0.17
Kayseri (1938–2002)
Average (°C)
STD (°C)
SE (°C)
–1.97
3.37
0.82
–0.15
3.26
0.79
4.46
2.43
0.59
10.61 15.04
1.72 1.25
0.42 0.30
19.00
1.17
0.29
22.45
1.23
0.30
21.86
1.36
0.33
17.12
1.50
0.36
11.41
1.79
0.44
5.18
2.13
0.52
0.47
3.09
0.75
10.46
0.94
0.23
Ürgüp (1970–2002)
Average (°C)
STD (°C)
SE (°C)
–1.41
3.35
1.14
0.28
3.21
1.10
4.67
2.21
0.75
10.10 14.01
1.75 1.22
0.60 0.42
18.10
1.08
0.37
21.51
1.47
0.50
20.58
1.27
0.43
16.10
1.46
0.50
10.74
1.92
0.65
5.02
2.02
0.69
0.70
2.51
0.86
10.03
0.90
0.31
Nev≠ehir (1960–2002)
Average (°C)
STD (°C)
SE (°C)
–0.58
3.19
0.95
0.65
3.09
0.92
4.59
2.20
0.66
9.87 14.30
1.88 1.39
0.56 0.41
18.24
0.98
0.29
21.41
1.53
0.46
20.86
1.36
0.41
16.77
1.37
0.41
11.56
1.93
0.58
6.18
2.31
0.69
1.76
2.48
0.74
10.47
0.87
0.26
Aksaray (1964–2002)
Average (°C)
STD (°C)
SE (°C)
0.11
3.46
1.08
1.83
3.13
0.98
6.26
2.07
0.65
11.38 15.93
1.77 1.16
0.55 0.36
19.97
0.94
0.29
23.36
1.38
0.43
22.57
1.36
0.43
18.20
1.30
0.41
12.66
1.63
0.51
6.79
1.90
0.60
2.38
2.52
0.79
11.79
0.86
0.27
–0.60
3.07
0.73
0.83
2.99
0.71
4.72
2.44
0.58
10.43 15.04
1.67 1.43
0.40 0.34
19.11
1.17
0.28
22.45
1.20
0.29
22.14
1.24
0.29
17.70
1.47
0.35
12.03
1.67
0.40
6.23
1.94
0.46
1.62
2.81
0.67
10.97
0.82
0.20
Ni¢de (1935–2002)
Average (°C)
STD (°C)
SE (°C)
used in a series of studies worldwide in order to differentiate mainly between patchy and widespread
precipitation (e.g. Huff and Shipp 1969; Sharon
1974, 1978, 1979).
To draw a CCM, one needs first to calculate a
correlation matrix of all possible combinations of
any two stations. There are two main advantages in
using CCM over simple correlation maps. First, unlike simple correlation maps where each map represents the spatial distribution of the correlation of
a single station with all the others, and therefore, n
different maps are required for n stations, here only
504
one composite map is prepared for any number of
stations. Second, in simple correlation maps the
isolines are based on only (n–1) correlation values,
which may be insufficient in the case of few observations, and therefore the derived map may be less
reliable. In a CCM n*(n–1)+1 correlation values
are mapped, which makes the isolines more realistic and reliable. However, the use of CCM implies
the assumption of spatial homogeneity of the precipitation fields, an assumption that can be made
taking into account the relatively small size of the
study region.
Geografiska Annaler · 87 A (2005) · 4
ROLE OF NCP ON CLIMATE IN TURKEY
Table 5. Calendar of the months belonging to the negative (N) or positive (P) phases according to the NCPI for the months when the
NCP is mainly active (October–April) Blank cells represent neutral conditions (adapted from Kutiel and Benaroch 2002).
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
Jan.
Feb.
Mar.
Apr.
May–Sep.
N
N
N
P
N
N
P
P
P
N
P
P
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
N
N
P
N
N
N
N
P
P
P
P
P
P
N
N
N
N
P
N
N
P
P
N
N
N
N
N
P
P
N
N
P
N
N
P
N
N
P
N
P
N
P
P
P
P
P
N
N
N
N
P
P
N
N
P
P
P
N
N
P
P
N
P
N
N
P
P
P
P
N
N
P
N
N
P
P
N
N
P
P
P
N
P
N
P
P
N
Each map is centred on the self-correlation
(=1.000) and the other correlation values (of each
station with all other stations) are mapped according to their distance and orientation relative to that
station. This procedure is repeated for each station,
yielding a correlation map that demonstrates a perfect symmetry in regard to the central point. In the
case of a region and/or a season predominantly
characterized by widespread precipitation, one
should expect higher correlation values compared
to a region and/or a season predominantly characterized by localized convective precipitation. FurGeografiska Annaler · 87 A (2005) · 4
Oct.
Nov.
Dec.
P
N
P
P
N
P
N
N
N
P
P
N
N
P
P
N
N
P
N
N
N
P
N
P
P
P
P
P
N
P
N
P
P
P
N
P
N
P
N
P
N
N
N
N
P
P
P
N
P
P
P
N
N
N
P
N
P
P
P
N
P
P
P
P
N
P
P
N
N
thermore, if the precipitations adopt a preferred orientation of propagation, one should expect that
along this orientation the correlation values will decrease at a slower rate compared to other directions
(Sharon 1978). Therefore, the use of correlation
maps may serve as a useful tool in the study of the
structure, origin and propagation of storms. However, it should be emphasized that inherent variability of the precipitation totals among the stations
is not reflected in correlation maps. A full description of the methodology and the related assumptions can be found in Sharon (1974).
505
H. KUTIEL AND M. TÜRKE≠
Fig. 1. Location map of the Middle Kızılırmak (Cappadocian) sub-region in Turkey (top) and the six stations used in the present study
(bottom)
Results and discussion
Influence of the NCP variability on mean
temperatures
During the study period from October to April,
monthly mean temperatures are considerably
higher for all months at all stations during the
NCP(–) phase as compared with the NCP(+)
506
phase. Figure 2 presents an example of the mean
monthly temperature differences at Kayseri between both phases.
Table 6 lists the average temperatures at the six
Cappadocian stations during NCP(–) and
NCP(+). These differences vary between 3.4°C at
Kır≠ehir and 3.9°C at Nev≠ehir. The greatest differences at the seasonal scale are observed in JanGeografiska Annaler · 87 A (2005) · 4
ROLE OF NCP ON CLIMATE IN TURKEY
Kayseri
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Fig. 2. An example of mean monthly temperature differences between NCP(–) and NCP(+) at Kayseri. The mean monthly temperature is shown for reference
-2.0
-4.0
-6.0
Oct
Nov
Dec
Jan
NCP(-)
uary and February, 5.9°C and 4.5°C respectively,
whereas, the smallest differences are observed in
November and March, 2.6°C and 2.5°C respectively (Table 6). Figure 3 shows the spatial distribution of the temperature differences between
NCP(–) and NCP(+). Figure 3a (taken from Ku-
Mean
Feb
Mar
Apr
NCP(+)
tiel et al. 2002) presents the regional impact of the
NCP on the temperature regime; Fig. 3b shows
the differences in Turkey; and Fig. 3c focuses on
the Cappadocian region. From this series of
maps, one can conclude that the influence of the
NCP on the temperature regime in Turkey is prob-
Table 6. Composite mean temperatures (in °C) during NCP(–) and NCP(+), and long- term average temperatures (1958–1998) at the
six stations of the Middle Kızılırmak (Cappadocian) sub-region. The last column represents the mean seasonal (seven months) difference
for each station, while the last row represents the mean spatial (six stations) difference for each month
Station
Kır≠ehir (1958–1998)
Kayseri (1958–1998)
Ürgüp (1970–1998)
Nev≠ehir (1960–1998)
Aksaray (1964–1998)
Ni¢de (1958–1998)
Oct.
NCP(–)
Average
NCP(+)
NCP(–)
Average
NCP(+)
NCP(–)
Average
NCP(+)
NCP(–)
Average
NCP(+)
NCP(–)
Average
NCP(+)
NCP(–)
Average
NCP(+)
Mean spatial
difference
Geografiska Annaler · 87 A (2005) · 4
Nov.
Dec.
Jan.
Febr.
Mar.
Apr.
13.8
12.1
10.9
13.1
11.3
9.9
12.8
10.8
9.9
13.7
11.6
10.0
14.5
12.6
11.1
13.6
11.8
10.5
7.4
6.1
5.1
5.9
4.9
3.9
6.5
5.0
3.2
7.6
6.1
4.5
8.0
6.7
5.5
7.3
6.0
5.0
3.5
2.1
0.1
2.2
0.5
–2.0
2.6
0.7
–0.9
3.4
1.8
–0.5
4.0
2.4
0.2
3.4
1.8
–0.7
2.2
–0.2
–3.3
0.8
–1.9
–5.3
1.8
–1.3
–4.0
2.2
–0.5
–3.7
3.4
0.2
–2.9
2.1
–0.5
–3.9
3.3
1.0
–1.3
1.9
–0.3
–2.8
2.4
0.2
–1.9
2.9
0.6
–1.7
4.1
1.7
–0.1
2.8
0.5
–2.0
6.6
5.2
4.2
6.3
4.7
3.8
6.2
4.5
3.4
5.9
4.4
3.3
7.3
6.1
5.3
6.4
4.8
3.7
12.2
10.5
9.3
12.0
10.5
9.4
11.6
10.0
8.8
11.6
9.8
8.3
12.8
11.3
10.0
11.8
10.3
9.2
3.2
2.6
3.7
5.9
4.5
2.5
2.8
Mean
seasonal
difference
3.4
3.6
3.6
3.9
3.6
3.7
507
H. KUTIEL AND M. TÜRKE≠
a
b
c
Fig. 3. The spatial distribution of
the temperature differences between NCP(–) and NCP(+). Values indicate the mean difference
between NCP(–) and NCP(+) (in
°C) for the period October–April:
(a) in the region (after Kutiel et al.
2002);(b) in Turkey; (c) in Cappadociaca
508
Geografiska Annaler · 87 A (2005) · 4
ROLE OF NCP ON CLIMATE IN TURKEY
a
b
c
Fig. 4. The spatial distribution of
the precipitation differences between NCP(–) and NCP(+). Values show differences between
NCP(–) and NCP(+) as a percentage of the average precipitation in the period October–April:
(a) in the region (after Kutiel et
al. 2002); (b) in Turkey; (c) in
Cappadocia
Geografiska Annaler · 87 A (2005) · 4
509
H. KUTIEL AND M. TÜRKE≠
a
1.5
1.5
0.81
0.90
1.0
1.0
0.91
0.96 0.82
0.85
0.91 0.57
0.86
0.76
[degrees of latitude]
[degrees of latitude]
0.58
0.65 0.90
0.5
0.67
0.32 0.78
0.78 0.74
0.0
0.66 1.00 0.66
0.74 0.78
0.78 0.32
0.67
-0.5
0.86
0.57 0.91
0.76
0.5
0.85
0.51
0.96 0.83
0.48 0.70
0.0
0.81 1.00 0.81
0.70 0.48
0.83 0.96
0.51
-0.5
0.93
0.92 0.77
0.90 0.65
0.58
-1.0
0.81
0.90
-1.5
-1.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-2.0
-1.5
-1.0
-0.5
[degrees of longitude]
b
1.5
0.85
0.79 0.88
0.76
0.40 0.84
0.92
0.63
0.83
0.94 0.72
0.82 0.89
0.0
0.72 1.00 0.72
0.89 0.82
0.72 0.94
0.83
-0.5
0.92
0.84 0.40
0.63
0.5
0.77
0.92 0.86
0.82 0.84
0.0
0.77 1.00 0.77
0.84 0.82
0.86 0.92
0.77
-0.5
0.93
0.91 0.81
0.93
0.88 0.79
0.85
0.68
-1.0
0.57
0.79
-1.5
-1.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-2.0
-1.5
-1.0
-0.5
[degrees of longitude]
0.0
0.5
1.0
1.5
2.0
[degrees of longitude]
1.5
1.5
0.69
0.69
1.0
1.0
0.87
0.70 0.83
0.5
0.77
0.54 0.79
0.62
0.51 0.88
0.80
0.61
[degrees of latitude]
[degrees of latitude]
2.0
0.68
0.81 0.91
0.93
0.93
0.65 0.87
0.70
-1.0
0.89
0.93 0.53
0.38 0.73
0.0
0.50 1.00 0.50
0.73 0.38
0.53 0.93
0.89
-0.5
0.80
0.88 0.51
0.61
0.5
0.62
0.87
0.34 0.81
0.93
0.59
0.80
0.61 0.69
0.74 0.31
0.0
0.14 1.00 0.14
0.80
-0.5
0.31 0.74
0.69 0.61 6
0.93
0.81 0.34
0.83 0.70
0.87
0.59
0.79 0.54
0.77
0.87
-1.0
-1.0
0.69
0.69
-1.5
-1.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-2.0
-1.5
-1.0
-0.5
[degrees of longitude]
0.0
0.5
1.0
1.5
2.0
[degrees of longitude]
1.5
1.5
0.26
0.68
1.0
1.0
0.69
0.80 0.71
0.5
0.93
0.81 0.77
0.94
0.66
[degrees of latitude]
[degrees of latitude]
1.5
0.79
[degrees of latitude]
0.5
0.76
0.90
0.72 0.74
0.71 0.86
0.0
0.74 1.00 0.74
0.86 0.71
0.74 0.72
0.90
-0.5
0.94
0.77 0.81
0.66
0.5
0.11 0.52
0.87
-0.07
0.86
0.68
0.65 1.00 0.65
0.63 0.69
0.76 0.60
0.68
-0.5
0.84 0.78
0.37
0.86
-1.0
0.37
0.78 0.84
0.60 0.76
0.69 0.63
0.0
0.71 0.80
0.69
0.93
0.87
0.52 0.11
-0.07
-1.0
0.68
0.26
-1.5
-1.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
[degrees of longitude]
510
1.0
1.0
0.70
0.87 0.65
d
0.5
1.5
1.0
[degrees of latitude]
0.0
[degrees of longitude]
0.57
c
0.48
0.82 0.96
0.91
0.62
-1.0
0.62
0.77 0.92
0.93
0.48
1.0
1.5
2.0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
[degrees of longitude]
Geografiska Annaler · 87 A (2005) · 4
ROLE OF NCP ON CLIMATE IN TURKEY
e
1.5
1.5
0.75
0.43
1.0
1.0
0.5
0.59
0.66 0.84
0.57
0.84 0.84
0.89
0.77
[degrees of latitude]
[degrees of latitude]
0.80
0.80 0.93
0.73
0.71 0.90
0.67 0.81
0.0
0.85 1.00 0.85
0.81 0.67
0.90 0.71
0.73
-0.5
0.89
0.84 0.84
0.77
0.5
0.54
0.57
0.80
0.75 0.91
0.76 0.76
0.0
0.66 1.00 0.66
0.76 0.76
0.91 0.75
0.80
-0.5
0.94
0.71 0.60
0.93 0.80
0.80
-1.0
0.75
0.43
-1.5
-1.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-2.0
-1.5
-1.0
-0.5
[degrees of longitude]
f
1.5
1.0
1.5
2.0
0.94
1.0
0.53
0.72 0.28
0.84
0.42 0.70
0.86
0.76
[degrees of latitude]
0.5
0.86
0.44
0.34 0.59
0.0
0.36 1.00 0.36
0.59 0.34
0.44
0.86
-0.5
0.86
0.70 0.42
0.76
0.5
0.94 0.98
0.99
0.87
0.92
0.89
0.96 1.00 0.96
0.76 0.75
0.91 0.90
0.89
-0.5
0.87 0.87
0.94
0.92
-1.0
0.94
0.87 0.87
0.90 0.91
0.75 0.76
0.0
0.28 0.72
0.53
0.84
0.99
0.98 0.94
0.87
-1.0
0.77
0.94
-1.5
-1.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
-2.0
-1.5
-1.0
-0.5
[degrees of longitude]
0.0
0.5
1.0
1.5
2.0
[degrees of longitude]
1.5
1.5
0.75
0.66
1.0
1.0
0.88
0.88 0.77
0.5
0.74
0.58 0.61
0.90
0.90 0.81
0.91
0.85
[degrees of latitude]
[degrees of latitude]
0.5
1.5
1.0
[degrees of latitude]
0.0
[degrees of longitude]
0.77
g
0.54
0.84 0.66
0.59
0.70
-1.0
0.70
0.60 0.71
0.94
0.94
0.91 0.82
0.81 0.84
0.0
0.82 1.00 0.82
0.84 0.81
0.82 0.91
0.94
-0.5
0.91
0.81 0.90
0.85
0.5
0.56 1.00 0.56
0.60 0.62
0.84 0.61
0.79
-0.5
0.74
0.68 0.53
0.76
0.61 0.58
0.74
0.75
-1.0
0.79
0.61 0.84
0.62 0.60
0.0
0.77 0.88
0.88
0.90
0.75
0.53 0.68
0.74
0.76
-1.0
0.75
0.66
-1.5
-1.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
[degrees of longitude]
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
[degrees of longitude]
Fig. 5. Composite correlation maps of monthly precipitation during NCP(–) (left) and NCP(+) (right). Values inside circles indicate
the correlation coefficients between a pair of stations. Circle sizes are proportional to the correlation coefficients. Note that each value
appears twice in a perfect symmetry in regard to the central point. (a) October, (b) November, (c) December, (d) January, (e) February,
(f) March and (g) April. Scale on both axes is in degrees of longitude and latitude
ably more evident than elsewere in the Middle
East. In Turkey itself, the Central Anatolian Plateau is more affected by the NCP than the coastal
regions, and within Central Anatolia, the Cappadocian region is probably the core of that influence.
Geografiska Annaler · 87 A (2005) · 4
Influence of the NCP variability on precipitation
totals
As mentioned earlier, we did not expect very large
differences in the seasonal precipitation between
the two phases due to their location. However, in
511
H. KUTIEL AND M. TÜRKE≠
the three westernmost stations of Kır≠ehir, Aksaray
and Ni¢de, more precipitation accumulated during
NCP(–) whereas in the northeastern stations of
Nev≠ehir and Kayseri, the opposite is true. These
results fit perfectly with our previous results concerning the role of the NCP on precipitation totals
in Turkey (Kutiel et al. 2002). Figure 4 shows the
spatial distribution of the precipitation differences
between NCP(–) and NCP(+). Figure 4a (taken
from Kutiel et al. 2002) presents the regional impact of the NCP on the precipitation regime, Fig. 4b
shows the differences in Turkey, and Fig. 4c focuses on the Cappadocian region. From this series of
maps, one can conclude that in the western part of
the Middle East more rainfall is associated with the
negative phase of the NCP whereas the opposite is
true in the eastern Middle East. Turkey is divided
into two almost equal halves with western-southwestern Turkey benefiting from more rainfall during NCP(–), and eastern-northeastern Turkey during NCP(+). The Cappadocian region is located in
this transitional zone.
Influence of the NCP variability on precipitation
fields
Figure 5 illustrates the various monthly CCM during both phases. Each map comprises 31 correlation values (6 stations*5 correlations + 1 self-correlation).
There are noticeable differences between the
various months and the two phases. One should
keep in mind that high correlations among the stations indicate widespread uniform precipitation,
whereas low correlations indicate more localized
showers. In general, during the winter months of
December–February, correlations are lower than in
the transitional months of October and November
on the one hand and March and April on the other.
In October, November and March correlations are
higher during NCP(+) than during NCP(–), whereas the opposite is true in April. The highest correlations were found in March (during NCP(–)) and
in April (during NCP(+))
The correlation results for October and November are expected, as the southerly to southwesterly
rains bringing pressure systems during these
months are not as strong as the northerly systems.
The higher spatial correlations during NCP(–) in
December, January and February than during the
NCP(+) are also expected results for the Cappadocian region. We would also expect that the highest
correlations be obtained in March and April, be512
cause precipitation in these months is characterized
by both northerly and southerly sector weather patterns. However, rainfall occurrences in April are
most likely associated with the local convective
showers and thunderstorms, in addition to the frontal mid-latitude depressions effective in the region.
Maximum precipitation amounts in May or April
are explained by the additional contribution of local convective showers and thunderstorms, the socalled ‘Kırkikindi ya¢murları’ (forty-afternoon
rains), to the frontal mid-latitude depression activities in the spring (Türke≠ et al. 2004). Dry (rainy)
conditions in the region are closely related to the
anticyclonic (cyclonic) circulation types or pressure centres over Turkey and/or its near surroundings. Thus, the local convective activities in the
Cappadocian region in April (and possibly May)
may have weakened the dependence of the precipitation occurrence in the region to the northerly
weather patterns.
Conclusions
According to Thornthwaite’s Moisture Index and
the Erinç’s Aridity Index, semi-arid and dry subhumid or semi-humid climate types prevail in Cappadocia. Dry sub-humid or semi-humid climatic
conditions concentrate only over the Nev≠ehir–
Ürgüp province. On the other hand, the UNCCD
aridity index indicates more humid conditions than
those of the other two climate indices. Dry sub-humid climate is dominant at all stations except at Aksaray in the south. Steppe is the dominant vegetation cover in Cappadocia with sparse dry forests.
The main purposes of the present study were to
validate the role of the NCP on the temperature and
precipitation regimes in the continental Central
Anatolia region of Turkey, which was postulated in
Kutiel et al. (2002). The obtained results not only
confirm the previous results but also strengthen
them.
Regarding the temperature regime, all obtained
temperature differences between the two phases
are equal to or greater than the highest values reported in Kutiel et al. (2002). Additional research
is needed to identify the exact location where the
maximum impact of the NCP on the temperature
regime occurs, although without doubt this is in
central Turkey. On the other hand, the present study
proved again that the NCP is the major upper level
atmospheric circulation governing the temperature
regime in that part of the world.
Concerning the precipitation regime, the present
Geografiska Annaler · 87 A (2005) · 4
ROLE OF NCP ON CLIMATE IN TURKEY
results proved again that central Turkey is located
in the transitional region between southwestern
Turkey that benefits from more precipitation during
the NCP(–) phase, and northeastern Turkey that
benefits from more precipitation during the
NCP(+) phase. However, the present results demonstrate that precipitation related to each of the two
phases differs in spatial structure. These differences are more evident during the transitional months
of October–November and March–April. In other
words, the role of the NCP on the precipitation regime can be detected not only by a comparison of
the total accumulated rainfall, but also by a comparison of their spatial structure which is a result of
the type and origin of the circulation.
H. Kutiel, Department of geography and Environmental Studies, University of Haifa, Haifa 31905,
Israel
E-mail: [email protected]
M. Türke≠, Department of geography, Faculty of
Sciences and Arts, Çanakkale Onsekiz Mart University, 17020, Çanakkale, Turkey
E-mail: [email protected]
References
·
Atalay, I , 2002: Ecoregions of Turkey. Orman Bakanlı¢ı
·
Yayınları No. 163. Meta Basımevi. Bornova – Izmir. 266 p.
(in Turkish).
Erinç, S., 1965: An attempt on precipitation efficiency and a new
·
index. Istanbul Üniversitesi Co¢rafya Enstitüsü Yayımları
·
No. 41. Baha Matbaası. Istanbul. 51p. (in Turkish).
Huff, F.A. and Shipp, W.L., 1969: Spatial correlations of storm,
monthly and seasonal precipitation. Journal of Applied
Meteorology, 8: 542–550.
Geografiska Annaler · 87 A (2005) · 4
Kutiel, H. and Benaroch, Y., 2002: North Sea – Caspian Pattern
(NCP) – an upper level atmospheric teleconnection affecting
the Eastern Mediterranean: Identification and definition. Theoretical and Applied Climatology, 71: 17–28.
Kutiel, H., Maheras, P., Türke≠, M. and Paz, S., 2002: North Sea
– Caspian Pattern (NCP) – an upper level atmospheric teleconnection affecting the eastern Mediterranean – implications
on the regional climate. Theoretical and Applied Climatology,
72: 173–192.
Sharon, D., 1974: The spatial pattern of convective rainfall in Sukumaland, Tanzania – A statistical analysis. Archiv für Meteorologie und Geophysik Bioklimatologie, Ser. B, 22: 201–
218.
Sharon, D., 1978: Rainfall fields in Israel and Jordan and the effect of cloud seeding on them. Journal of Applied Meteorology, 17: 40–48.
Sharon, D., 1979: Correlation analysis of the Jordan Valley rainfall field. Monthly Weather Review, 107: 1042–1047.
Thornthwaite, C.W., 1948: An approach toward a rational classification of climate. Geography Review, 38: 55–94.
Türke≠, M., 1996: Spatial and temporal analysis of annual rainfall
variations in Turkey. International Journal of Climatology,
16: 1057–1076.
Türke≠, M., 1999: Vulnerability of Turkey to desertification with
respect to precipitation and aridity conditions. Turkish Journal of Engineering and Environmental Science, 23: 363–380.
·
Türke≠, M., Sümer, U.M. and Demir, I ., 2002: Re-evaluation of
trends and changes in mean, maximum and minimum temperatures of Turkey for the period 1929–1999. International
Journal of Climatology, 22: 947–977.
Türke≠, M., Kutiel, H. and Akgündüz, S., 2004: Climate of the
Middle Kizilirmak (Cappadocian) region in Turkey (submitted for publication).
UNCCD, 1995: The United Nations Convention to Combat Desertification in those Countries Experiencing Serious Drought
and/or Desertification, Particularly in Africa. United Nations
Environment Programme (UNEP). Geneva. 71 p.
UNEP, 1993: World Atlas of Desertification. United Nations Environment Programme (UNEP). London.
Willmott, C.J., 1977: WATBUG: A FORTRAN IV Algorithm for
Calculating the Climatic Water Budget. Water Resources
Center, University of Delaware. Newark, Delaware.
Manuscript received February 2005, revised and accepted August
2005.
513