Verification of the Seecof-5 Summer 2011 Climate Outlook for the Territory of Serbia in Relation to Different Climatological Reference Periods

VERIFICATION OF THE SEECOF-5 SUMMER 2011 CLIMATE OUTLOOK FOR THE TERRITORY OF SERBIA IN RELATION TO DIFFERENT CLIMATOLOGICAL REFERENCE PERIODS

VERIFICATION OF THE SEECOF-5 SUMMER 2011 CLIMATE OUTLOOK FOR THE TERRITORY OF SERBIA IN RELATION TO THE 1961-1990 CLIMATOLOGICAL PERIOD

Temperature

According to the SEECOF-5 outlook, in the northern part of Serbia, the summer of 2011 was expected to be warmer than normal (temperature in the third tercile) with 50% probability, normal with 40% probability and below normal with 10% probability, compared to the 1961-1990 climatological reference period. In the rest of Serbia the normal temperature was expected with 40% probability, above normal with 40% probability and below normal with 20% probability. Meteorological monitoring showed that temperature was above normal in the whole of Serbia (according to the tercile method). The outlook of a hot summer was more correct for the northern part of Serbia, than for the rest of the country. According to the outlook, the probability of a cooler summer was very low (10-20%), which also came true for the whole Serbia.

Precipitation

The SEECOF-5 climate outlook for the summer of 2011 in Serbia did not show a clear signal concerning the precipitation over the country. The monitoring of precipitation showed dry summer conditions in most parts of Serbia, with the exception of mountainous areas of western Serbia and the eastern part of central Serbia, where the summer was in the normal category. The SEECOF 5 precipitation outlook did not suggest a dry summer in Serbia.

1 JJA 2011 JJA 2 011 Temperature according to percentile classification (terciles) Precipitation amount according to percentile classification (terciles) (Reference period 1961-1990) (Reference period 1961-1990)

PERCENTILES CATEGORIES PERCENTILES CATEGORIES

>66 WET >66 WARM

33-66 NORMAL 33-66 NORMAL

<33 COLD <33 DRY

Picture 1. Monitoring of the summer of 2011 Picture 2. Monitoring of the summer of 2011 temperature in Serbia by using the tercile method, precipitation in Serbia by using the tercile in relation to the 1961-1990 reference period. method, in relation to the 1961-1990 reference period.

Analysis of the 2011 summer season in Serbia compared to the 1961-1990 reference period

Temperature

Mean summer temperature anomalies (compared to the 1961-1990 reference period) were positive in all of Serbia, and ranged from 1.1 to 2.4 ˚C. According to the percentile method, mean summer temperatures were in the extremely hot category in most parts of Serbia, except in certain areas where it was very warm.

JJA 2011 JJA 2011. Temperature anomaly Temperature according to percentille classification (Reference period 1961-1990) (Reference period 1961-1990)

(° C ) PERCENTILES CATEGORIES

>98 EXTREMELY WARM 4

3 91-98 VERY WARM

2 76-90 WARM 1

25-75 NORMAL 0

-1 10-24 COLD

-2 2-9 VERY COLD -3

EXTREMELY COLD -4 <2

-5

Picture 3. Mean seasonal temperature anomaly in Picture 4. Assessment of mean seasonal Serbia during the summer of 2011, compared to temperature in Serbia during the summer of 2011 the 1961-1990 climatological reference period. by using the percentile method, compared to the 1961-1990 climatological reference period.

The maximum daily temperature in Serbia during the summer of 2011 was measured in the country’s far south, at the Leskovac station, and amounted up to 39.4˚ C, while the lowest daily temperature, measured at Mount Kopaonik (1710mnv) on June 26, was only 1.9˚ C. During the summer of 2011, the number of summer days with maximum daily temperature above 25˚C in Serbia was 9 to 15 days (in Sjenica, southwestern Serbia) higher than normal. The number of tropical days with maximum temperature above 30˚C was 12 to 25 days (5 to 8 days at the mountains) larger than normal. The number of tropical nights, with minimum temperature above 20˚C, was above average in whole Serbia, except in the far southeast, where it was around normal. The largest anomalies occurred in the northern parts of the country (in Belgrade 15, and in Zrenjanin 13 tropical nights).

3 JJA 2011 JJA 2011 Summer days anomaly Tropical days anomaly ( Refence period 1961-1990 ) (Reference period 1961-1990)

25 25

20 20

15 15

10 10

5 5

0 0

Picture 5. Number of summer days anomaly Picture 6. Number of tropical days anomaly during the summer of 2011, in relation to the during the summer of 2011, in relation to the 1961-1990 normal. 1961-1990 normal.

If the summer temperatures measured at stations in Serbia during the 1949- 2011 period were sorted in descending order, the following table, showing that the summer of 2011 was one of the warmest in the order (its position ranging from the third to the twelfth place, with the exception of Zajecar, where it took the eighteenth place), would be obtained:

STATION 2011 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 PALIC 9 2003 2007 1992 2002 1994 1952 1950 2000 2011 1998 2008 2009 1963 2010 1988 1995 1999 1993 1957 1951 SOMBOR 11 2003 1952 1950 2000 2007 1992 1994 2002 2008 2009 2011 1998 1963 2010 1988 1995 1951 1957 1993 2006 KIKINDA 12 2003 1992 2007 2000 1952 1950 2002 1994 1963 2008 2009 2011 2010 1998 1993 1957 1995 1951 2001 1988 BECEJ 3 2003 2007 2011 1992 2008 2009 2002 2000 1994 1998 1952 1950 2010 1999 2006 1963 1995 1951 2004 1957 NOVI SAD 10 2003 1950 1952 2000 2007 1992 1963 2002 1994 2011 1988 2008 2009 2010 1951 1998 1957 1958 1993 1971 ZRENJANIN 10 2003 1950 2007 1952 1992 2000 2002 1963 2008 2011 1994 2009 2010 1998 1957 1951 1988 1993 1958 2001 VRSAC 8 2007 1952 2003 1950 2000 1992 1963 2011 2008 2002 1998 2010 2009 1994 1957 1953 1951 2001 1999 1988 LOZNICA 4 2003 2007 2000 2011 1992 1952 2008 2002 1994 1998 2010 1988 2009 1963 1950 2004 1999 2001 1957 1987 S.MITROVICA 8 2003 1952 1950 2000 2007 1992 1963 2011 1994 2002 2008 2010 1998 1957 2009 1951 1958 1999 1988 1960 VALJEVO 4 2003 2007 2000 2011 1952 2010 2008 1950 1998 1992 1963 2009 2002 1994 1988 1958 1987 1993 1957 2006 BEOGRAD 6 2003 2007 2000 1950 2008 2011 1952 1992 1963 1998 2010 2002 1994 2009 1988 1993 1957 1995 1958 1987 KRAGUJEVAC 7 2007 1950 2003 1952 2000 2008 2011 1963 2002 1998 2010 2009 1994 1993 1992 2001 1958 1996 1957 1951 SM.PALANKA 7 2007 2003 1952 1950 2000 1963 2011 1998 1992 2008 2002 1988 1994 2010 2009 1993 1958 1951 1953 1987 V.GRADISTE 9 2003 2007 1950 1952 2000 1963 2008 2002 2011 2010 1992 2009 1998 1953 1994 1958 1954 1988 1951 1957 NEGOTIN 7 2007 2003 2000 2002 2010 2008 2011 1988 2009 1993 1992 1952 1950 2001 1998 1996 1994 1999 1958 1987 ZLATIBOR 8 2007 2003 1952 1950 2000 1998 2008 2011 1992 2010 2009 1988 1994 1963 2002 1958 2001 1993 1954 1987 SJENICA 6 2007 2003 1952 1950 1998 2011 2000 2010 1988 2008 2009 2002 1999 1954 1994 1987 1963 1957 2001 1992 POZEGA 7 2003 2007 1952 2002 1998 2010 2011 2000 1963 2008 2009 1958 1988 1953 1957 1954 1999 2001 1994 1993 KRALJEVO 8 2007 2003 1952 1950 2000 1998 1963 2011 1958 2002 1993 2008 1994 2010 2009 1988 1954 2001 1951 1992 KURSUMLIJA 4 2007 2003 1952 2011 1963 2010 1988 2002 2000 2008 2009 1987 1958 1954 1998 2001 1992 1953 1996 1956 KRUSEVAC 8 2007 2003 1952 1950 2000 1998 2009 2011 1963 2008 2010 1958 2002 1994 1993 1951 1996 1953 2001 1988 CUPRIJA 8 1950 1952 2007 2003 2000 1963 1998 2011 2008 1992 2010 1951 1994 2002 1953 1958 1993 2009 1954 2001 NIS 7 2007 1952 2003 1950 1998 2000 2011 1963 2008 2010 1958 1993 1994 1953 1951 1992 1996 1954 2009 2002 LESKOVAC 9 2007 1952 2003 1950 1963 1958 2000 2010 2011 1998 2008 1996 1993 1951 1954 1957 1953 2002 1992 1972 ZAJECAR 18 2007 1950 2000 2003 1952 1998 2002 2010 1996 1988 1958 1994 2008 1992 1963 1993 1999 2011 2001 1987 DIMITROVGRAD 9 1950 1952 2007 2003 1958 1963 2000 2008 2011 1998 2010 1954 1951 1987 1996 1953 1993 1957 2002 1988 VRANJE 10 2007 1950 1952 2003 2000 1963 1998 1958 1993 2011 2008 1996 2010 1954 1988 1951 2001 1994 1992 1987 1949 1950-1969 1970-1989 1990-1999 2000-2009 2010-2011

Picture 7. Descending order of hottest summers for the 1949-2011 period, measured at the stations in Serbia (20 warmest summers per each station)

4 Mean summer air temperature anomalies from the 1961-1990. normal Beograd - period 1949-2011. 4.0 2010-2011 2000-2009 3.5 1990-1999 3.0 1970-1989 1950-1969 2.5 2011 1949

2.0

1.5 C) from the 1961-1990. normal 1961-1990. the from C) o

1.0

0.5 Anomaly Tsr ( 0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 20032007200019502008201119521992196319982010200219942009198819931957199519581987 3.5 3.5 3.0 2.7 2.5 2.5 2.5 2.4 2.3 2.3 2.2 2.1 2.1 2.0 1.7 1.5 1.3 1.3 1.2 1.2 24.6 24.5 24.1 23.7 23.5 23.5 23.5 23.4 23.4 23.3 23.2 23.1 23.1 23.0 22.7 22.5 22.3 22.3 22.3 22.2 Ordinal year - year - anomaly Tsr (oC) from the 1961-1990. normal - Tsr Picture 8. Descending order of 20 hottest summers in Belgrade for the 1949-2011 period

Mean summer air temperature anomalies from the 1961-1990. normal Beograd - period 1888-2011. 4.0 2010-2011 2000-2009 3.5 1990-1999 1970-1989 3.0 1950-1969 1930-1949 2011 2.5 1910-1929 1888-1909 2.0

1.5 C) from the 1961-1990. normal 1961-1990. the from C) o

1.0

0.5 Anomaly Tsr ( 0.0 1 2 3 4 5 6 7 8 9 1011121314151617181920 20031946200720001950200820111952199219631998192820101931200219941927200919881942 3.5 3.5 3.5 3.0 2.7 2.5 2.5 2.5 2.4 2.3 2.3 2.3 2.2 2.1 2.1 2.1 2.0 2.0 1.7 1.7 24.6 24.5 24.5 24.1 23.7 23.5 23.5 23.5 23.4 23.4 23.3 23.3 23.2 23.2 23.1 23.1 23.0 23.0 22.7 22.7

Ordinal year - year - anomaly Tsr (oC) from the 1961-1990. normal - Tsr Picture 9. Descending order of 20 hottest summers in Belgrade during the 1888-2011 period

5 central Serbia in the first half of July. The second heat wave was registered in the third decade of August, and its maximum duration was up to 13 days. In Vojvodina, the August heat wave lasted shorter, while it was not recorded at all in the far east of Serbia.

Precipitation

Summer precipitation sums in Serbia in 2011 were below the average value for the 1961-1990 normal period (the percentage achieved was from 45% to 98% of the average). According to the percentile method, summer precipitation sums in northwestern, western and the parts of eastern Serbia were in dry to extremely dry categories, while in the other parts of the country, they were in the normal category.

JJA 2011 JJA 2011. Precipitation in percent of normal Precipitation amount according to percentille classification (Reference period 1961-1990) (Reference period 1961-1990)

( % ) PERCENTILES CATEGORIES 400 >98 EXTREMELY WET 350

300 91-98 VERY WET 275

250 76-90 WET 225

200

175 25-75 NORMAL

150

125 10-24 DRY 100

75 2-9 VERY DRY 50

25 <2 EXTREMELY DRY 0

Picture 11. Assessment of precipitation sums for Picture 10. Precipitation sum for the summer of the summer of 2011 in Serbia by using the 2011 in Serbia in percentages from the 1961-1990 percentile method, for the 1961-1990 reference normal. period.

The maximum daily precipitation of 82.1mm was measured on Crni Vrh Mountain (1037m), eastern Serbia, on July 30, 2011, thus exceeding the former July daily precipitation maximum for that station.

During the summer of 2011, the number of days with precipitation higher than or equal to 1mm was 1 to 12 days lower than the 1961-1990 period average. The biggest discrepancy of 12 days occurred in the parts of western Serbia.

6 JJA 2011 Days with precipitation ≥ 1mm anomaly (Reference period 1961-1990)

-2

-4

-6

-8

-10

-12

Picture 12. Discrepancy between the number of days during the summer of 2011with precipitation higher than or equal to 1mm and the 1961-1990 period average.

Analysis of the 2011 summer season for Serbia compared to the 1971-2000 climatological reference period

Temperature

Anomalies of mean summer temperatures from normal (in relation to the 1971-2000 reference period) were positive in entire Serbia, and ranged from 1.1 to 2.1˚C (picture 13). According to the percentile method (compared to the 1971-2000 reference period), most of the country was in the very hot category, parts of northern and eastern Serbia were in the hot category, while three stations were in the extremely hot category. Monitoring according to the tercile method (for the 1971-2000 reference period, Picture 15) showed that temperature on the whole Serbian territory was in the hot category (just as for the 1961-1990 period).

7 JJA 2011 Temperature anomaly (Reference period 1971-2000)

( ° C )

-1

-2

-3

-4

-5

Picture 13. Mean seasonal temperature anomalies in Serbia during the summer of 2011 from the 1971- 2000 normal.

JJA 2011 JJA 2011 Temperature according to percentille classification Temperature according to percentile classification (terciles) (Refrerence period 1971-2000) (Reference period 1971-2000)

PERCENTILES CATEGORIES PERCENTILES CATEGORIES

>98 EXTREMELY WARM

91-98 VERY WARM >66 WARM

76-90 WARM

25-75 NORMAL 33-66 NORMAL

10-24 COLD

2-9 VERY COLD <33 COLD

<2 EXTREMELY COLD

Picture 14. Assessment of air temperature in Picture 15. Assessment of temperature in Serbia Serbia for the summer of 2011 by using the for the summer of 2011 by using the tercile percentile method, compared to the 1971-2000 method, compared to the 1971-2000 reference reference period. period.

Two heat waves were recorded on the Serbian territory during the summer of 2011 (Heat wave definition: period of 6 or more consecutive days in which the maximum temperature is minimum 5.1˚C higher than the average maximum temperature for each of those days during the 1971-2000 period). The first heat wave was recorded at two stations in mid July, and it lasted 8 days. The second heat wave occurred in the third decade of August, and its maximum duration was up to 10 days. In Vojvodina (northern Serbia), the August heat wave lasted shorter, while it was not recorded at all in the far east of Serbia.

Precipitation

Monitoring of the precipitation for the summer of 2011 by using the achieved percentage from the 1971-2000 normal method showed that there was a deficit of precipitation in almost entire Serbia (Picture 16). The precipitation sum (for the 1971-2000 period) ranged from normal to extremely dry category, according to the percentile method (Picture 17). The analysis of the summer precipitation by employing the tercile method (Picture 18) showed that it was dry in most part of the country, with the exception of the mountainous area of western Serbia and the eastern part of central Serbia, where precipitation was in the normal category (the same as in the 1961-1990 period).

JJA 2011 Precipitation in percent of normal (Reference period 1971-2000)

( % )

400

350

300

275

250

225

200

175

150

125

100

Picture 16. Summer precipitation sums in Serbia in 2011 in achieved percentages from the 1971-2000 normal.

JJA 2011 JJA 2011 Precipitation amount according to percentille classification Precipitation amount according to percentile classification (terciles) (Reference period 1971-2000) (Reference period 1971-2000)

PERCENTILES CATEGORIES PERCENTILES CATEGORIES

>98 EXTREMELY WET

91-98 VERY WET >66 WET

76-90 WET

25-75 NORMAL 33-66 NORMAL

10-24 DRY

2-9 VERY DRY <33 DRY

<2 EXTREMELY DRY

Picture 17. Assessment of precipitation sum in Picture 18. Assessment of precipitation sum in Serbia during the summer of 2011 by using the Serbia during the summer of 2011 by using the percentile method, in relation to the 1971-2000 tercile method, in relation to the 1971-2000 reference period. reference period.

Analysis of the 2011 summer season for Serbia compared to the 1981-2010 reference period

Temperature

Anomalies of air temperatures during the summer of 2011 in relation to the 1981-2010 reference period were positive in entire Serbia and ranged from 0.1 to 1.4˚C (Picture 19). According to the percentile method, most part of the country was in the hot or very hot category, while some parts of northern and eastern Serbia were in the normal category (Picture 20). According to the tercile method (Picture 21), mean summer temperatures were in the hot category in entire Serbia (the same as in the 1961-1990 and 1971-2000 periods).

JJA 2011 Temperature anomaly (Reference period 1981-2010)

( ° C )

-1

-2

-3

-4

-5

Picture 19. Mean seasonal temperature anomalies in Serbia during the summer of 2011 from the 1981-2010 normal.

JJA 2011 JJA 2011 Temperature according to percentille classification Temperature according to percentile classification (terciles) (Refrerence period 1981-2010) (Reference period 1981-2010)

PERCENTILES CATEGORIES PERCENTILES CATEGORIES

>98 EXTREMELY WARM

91-98 VERY WARM >66 WARM

76-90 WARM

25-75 NORMAL 33-66 NORMAL

10-24 COLD

2-9 VERY COLD <33 COLD

<2 EXTREMELY COLD

Picture 20. Assessment of air temperature in Picture 21. Assessment of air temperature in Serbia Serbia for the summer of 2011 by using the for the summer of 2011 by using the tercile percentile method, compared to the 1981-2010 method, compared to the 1981-2010 reference reference period. period.

Two heat waves were recorded on the Serbian territory during the summer of 2011 (Heat wave definition: period of 6 or more consecutive days in which the maximum temperature is minimum 5.1˚C higher than the average maximum temperature for each of those days during the 1981-2010 period). The first heat wave was recorded at one station in the second decade of July, and it lasted 8 days. The second heat wave occurred in the third decade of August, it was recorded at three stations and lasted 6 days.

Precipitation

Summer precipitation sums were below average value, just as in the 1961- 1990 and 1971-2000 periods. Only one station in the east of the country recorded precipitation surplus (the same as for the 1971-2000 period) of 9% (Picture 22). The percentile method analysis showed that a larger part of Serbia was within the normal limits (compared to the 1981-2010 reference period), while the other areas were below normal (Picture 23). According to the tercile method analysis (in relation to the 1981-2010 period, Picture 24), a larger part of the country was in the dry category, while the area with normal values expanded (to the parts of central, eastern and northeastern Serbia) in comparison to the other two periods.

11 JJA 2011 Precipitation in percent of normal (Reference period 1971-2000)

(%)

400 350 300 275 250 225 200 175 150 125 100 75 50 25 0

Picture 22. Precipitation sums in Serbia during the summer of 2011 in percentages from the 1981-2010 normal.

JJA 2011 JJA 2 011 Precipitation amount according to percentille classification Precipitation amount according to percentile classification (terciles) (Reference period 1981-2010) (Reference period 1981-2010)

PERCENTILES CATEGORIES PERCENTILES CATEGORIES

>98 EXTREMELY WET

91-98 VERY WET >66 WET

76-90 WET

25-75 NORMAL 33-66 NORMAL

10-24 DRY

2-9 VERY DRY <33 DRY

<2 EXTREMELY DRY

Picture 23. Assessment of seasonal precipitation Picture 24. Assessment of seasonal precipitation sums in Serbia during the summer of 2011 by sums in Serbia during the summer of 2011 by using the percentile method, in relation to the using the tercile method, in relation to the 1981- 1981-2010 reference period. 2010 reference period.

During the summer of 2011, there was no significant rise in water level of Serbian rivers. In August 2011, water levels of Serbian rivers varied within the domain of low and very low values. New historically lowest water levels were recorded in the Velika Morava river basin.