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Workshop: Climate Change, Water Resources and Food Security in Kazakhstan
THE CURRENT TRENDS OF WINTER AIR TEMPERATURE AND PRECIPITATION CHANGES
IN WEST KAZAKHSTAN
Aliya Ospanova
[email protected] aRepublican State Enterprise “Kazhydromet”
The air temperature changes in a specific region can manifest itself in
various ways. Analysis of the regional climate changes and, primarily of its
extreme characteristics is of special interest.
The specific physiographic features of Kazakhstan have a significant
impact on formation of weather conditions under which favorable and
unfavorable weather events arise. Air temperature is a highly variable
meteorological value both in space and time. Therefore, it is essential to
evaluate fluctuations and future climate changes. The thermal regime in
Kazakhstan is mainly defined by radiation factors that change because of the
large latitudinal extent and physiographic heterogeneity. In this case, the
impact of air circulation, which manifests itself in the complicated
interchange of cold and warm air mass outflows and in their interaction in the
seasonal baric conditions, is also substantial. Combination of these factors
causes a wide variety of temperature conditions in West Kazakhstan.
The monthly mean air temperature data was recorded for the period
between 1971 and 2000 in 6 meteorological stations in West Kazakhstan
(Aktobe, Atyrau, Uralsk, Zhalpaktal, Zhambeity, Taipak), which are
relatively equally spaced in the territory. For winter months, air temperature
field anomalies were investigated using N.A.Bagrov’s criterion:
where
m – number of stations;
∆Тi – monthly mean air temperature anomaly at the station i;
σi – mean square deviation
Years with significant air temperature anomalies, annual course for air
temperature and distribution of precipitations for months with extremely cold
air temperature were also identified.
INTRODUCTION
At all stations, the maximum air temperature was observed in July while the
minimum temperature in January. The total annual precipitation range from 190 to
307 mm. The maximum amount of precipitation occurs in a warm period (average in
the area is 161 mm). In a cold period, it amounts 90 mm.
The average number of days with strong frosts was also calculated. The average
number of days with air temperature ≤ minus 25˚ ranges from 4 (at the Meteorological
Station (MS) Atyrau) to 18 days (at the MS Aktobe). The air temperature below ≤
minus 40 ˚С is rarely observed (0.1 day).
The absolute minimum temperatures in winter months range from minus 34 ˚С at the
MS Zhalpaktal to minus 48 ˚С at the MS Aktobe.
The analysis of time variation of the average monthly temperature showed that the
average monthly temperature decreases in December in the most part of the area (the
trend is minus 0.1 ˚С/10 years) whereas it increases in January and February
(coefficient of a linear trend is 0.1-0.9 ˚С/10 years).
The mean values of winter air temperature calculated by the selected series turned
out to be higher than the values mentioned in climatology directories by 1-2.8 ˚С.
The analysis of time variation of precipitation revealed that the decrease in
precipitation also occurs in December (coefficient of a linear trend is 0.2-
4 mm/10 years). In January and February precipitation increased by 1-3 mm/10 years
at the MS Atyrau, Aktobe, and Uralsk while it reduced by 1-2 mm/10 years at the other
stations in the same months but the decrease was not significant.
Table 1.The catalogue of the months and years with extremely cold (EC) air temperature
Table 2. Distribution of precipitations in the extremely cold months
RESULTS
Observed changes in regional temperature and precipitation are
physically related to one another. The research results suggest strong
relationship between precipitation and temperature. Precipitation tends
to be insufficient in extremely cold months (in 77 % of cases).
CONCLUSION
DATA Months Years Total
December
January
February
1976, 1978, 1984, 1997
1972, 1973, 1974, 1977, 1980, 1987, 1996
1971, 1976, 1982, 1994
4
7
4
Months Excess precipitations Shortage of precipitations
December
January
February
1978
1987
1971
1976, 1984, 1997
1972, 1974, 1977, 1980, 1996
1976, 1982
∑ 3 (23 %) 10 (77 %)
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
19
71
19
72
19
73
19
74
19
75
19
76
19
77
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
Tem
pe
ratu
re (
t °
C)
December January February
y = 0,1x - 13,3 R² = 0,1964
-25,0
-20,0
-15,0
-10,0
-5,0
0,0
19
71
19
73
19
75
19
77
19
79
19
81
19
83
19
85
19
87
19
89
19
91
19
93
19
95
19
97
19
99
20
01
20
03
20
05
20
07
20
09
t, °
С
Years
Figure 1. West Kazakhstan temperature trends by winter months 1970-2000
Figure 2. The number of frost days per year in Uralsk and Taypak from 1940 to 2010
Figure 3. The average monthly course for air temperature in February at the MS Taypak
