events in summer have been increasing. Wibig (2012) recorded a strong relationship
between hot weather and lack of precipitation. Over the year no significant changes
have been observed in the annual amounts of precipitation, but more interestingly, a
decreasing summer precipitation trend has been found. March is the only month where
a significant precipitation increase was detected.
In Hungary the general annual twentieth century warming of about 0.8
C (most
expressed in summer by increase of about 1
C) initiated an extended calculation of
extreme temperature and precipitation indices for the whole country using grids of
the basic variables daily temperature and precipitation (Lakatos et al. 2011). Countrywide the grid point average of hot days (Tmax >¼ 30
C) and warm nights
(Tmin >¼ 20
C) showed a remarkable increase beginning in the 1980s. Maps
allow for a better identification of the most sensitive regions of the country. These
maps coincide with the Austrian studies (Nemec et al. 2012) which state that
warming does not necessarily cause more heavy precipitation. Changes of the
annually greatest 1-day total rainfall between 1961 and 2009 vary from À15 to
+10 mm. This increase could be detected mainly in the regions east of the Danube.
Precipitation in general has decreased by 11 % in Hungary since 1901, especially
since the 1970s. This decrease in precipitation is especially pronounced in spring.
Although summer precipitation does not display a special negative trend drought
events with dry and warm months are immanent in the climate of Hungary. The
Hungarian plains are most affected, with drying occurring in late spring/early
summer and during late autumn.
Romania has experienced a warming of about 0.5
C in annual mean temperature since 1901, and in the south eastern region trends up to 1
C have been
estimated. Summer temperatures have been increasing since the 1970s with highest
positive anomalies in the Northeast and Southwest of the country. During the hot
summer of 2007 temperatures above 40
C have been recorded during periods with
maximum temperatures of 35
C (Busuioc et al. 2007). Winter temperatures have
been increasing more steadily during the last century leading to the warmest winter
in 2006/2007 with an anomaly of about +6
C. As stated previously, no uniform
long-term precipitation change pattern was detected in Romania. There are some
smaller regions with increases and decreases in other regions. Extreme precipitation
events and their variability have been studied by Cazacioc (2007) for 1961–1996.
On average, the daily maximum precipitation amount is highest in the southwestern mountainous region (up to 68 mm) whereas in central Romania rather
low rainfall of around 30 mm can be experienced. Maximum daily precipitation has
mainly decreased during this period, most significantly more or less only in the
south-western mountain region. On the other hand slight growing trends have been
found partly in western and north-western regions of Romania.
2.3.1 Global and European Trends
For at least the last 500 years, European winters were generally colder than those of
the twentieth century, except for two short periods around 1530 and 1730
2 Climate Change in Central and Eastern Europe
23
between hot weather and lack of precipitation. Over the year no significant changes
have been observed in the annual amounts of precipitation, but more interestingly, a
decreasing summer precipitation trend has been found. March is the only month where
a significant precipitation increase was detected.
In Hungary the general annual twentieth century warming of about 0.8
C (most
expressed in summer by increase of about 1
C) initiated an extended calculation of
extreme temperature and precipitation indices for the whole country using grids of
the basic variables daily temperature and precipitation (Lakatos et al. 2011). Countrywide the grid point average of hot days (Tmax >¼ 30
C) and warm nights
(Tmin >¼ 20
C) showed a remarkable increase beginning in the 1980s. Maps
allow for a better identification of the most sensitive regions of the country. These
maps coincide with the Austrian studies (Nemec et al. 2012) which state that
warming does not necessarily cause more heavy precipitation. Changes of the
annually greatest 1-day total rainfall between 1961 and 2009 vary from À15 to
+10 mm. This increase could be detected mainly in the regions east of the Danube.
Precipitation in general has decreased by 11 % in Hungary since 1901, especially
since the 1970s. This decrease in precipitation is especially pronounced in spring.
Although summer precipitation does not display a special negative trend drought
events with dry and warm months are immanent in the climate of Hungary. The
Hungarian plains are most affected, with drying occurring in late spring/early
summer and during late autumn.
Romania has experienced a warming of about 0.5
C in annual mean temperature since 1901, and in the south eastern region trends up to 1
C have been
estimated. Summer temperatures have been increasing since the 1970s with highest
positive anomalies in the Northeast and Southwest of the country. During the hot
summer of 2007 temperatures above 40
C have been recorded during periods with
maximum temperatures of 35
C (Busuioc et al. 2007). Winter temperatures have
been increasing more steadily during the last century leading to the warmest winter
in 2006/2007 with an anomaly of about +6
C. As stated previously, no uniform
long-term precipitation change pattern was detected in Romania. There are some
smaller regions with increases and decreases in other regions. Extreme precipitation
events and their variability have been studied by Cazacioc (2007) for 1961–1996.
On average, the daily maximum precipitation amount is highest in the southwestern mountainous region (up to 68 mm) whereas in central Romania rather
low rainfall of around 30 mm can be experienced. Maximum daily precipitation has
mainly decreased during this period, most significantly more or less only in the
south-western mountain region. On the other hand slight growing trends have been
found partly in western and north-western regions of Romania.
2.3.1 Global and European Trends
For at least the last 500 years, European winters were generally colder than those of
the twentieth century, except for two short periods around 1530 and 1730
2 Climate Change in Central and Eastern Europe
23