Joint International Conference on Long-term Experiments ...

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Figure no.3: Variation of the medium number of the
winter days (maximum temperature ≤0ºC) in the
Crisul Repede hydrographical basin during the
period 1970-2005
I II III IV V VI VII VIII IX X XI XII An
Borod
Oradea
Sacueni
Stâna de Vale
Throughout the year, the winter days can be produced from November until March at
low altitudes and from October to April at high altitudes. The number of winter days
from the Crisul Repede hydrographical basin reaches the highest value of 48.8 days at
Stâna de Vale meteorological station and the lowest value of 22.9 days in Oradea.
Throughout the year, the highest frequency of these days is recorded in January 13.9
days at Stâna de Vale, when the entire year’s highest value is reached, while the lowest
number of winter days is recorded in March at Oradea 0.8 days. Winter days also take
place in large numbers in February and December, while starting with March, along
with the general warming of the atmosphere, to drop significantly at plain stations and
starting with April to decrease almost totally at Stâna de Vale (1.1 days) (fig.3).
4. Average frequency of summer days (maximum temperature.≥25ºC)
High temperatures are usually recorded in case of anticyclone regime, described by the
invasion of dry continental air from medium latitudes or tropical air from Central Asia
or Northern Africa. In these conditions a very hot weather sets in, accompanied by dry
winds. Usually the summer days settle in during the April-October period.
An average number of 80-90 days per year are recorded in plain meteorological
stations, 61.1 days in depressions, while as the altitude increases, the average number of
days drops, reaching at 9.3 days at Stâna de Vale (fig.4).
Over the year, the maximum number of summer days is reached in July (17.8 days
at Borod, 22.8 days at Oradea, 21.7 days at Săcueni) at low altitudes and in August, at
high altitudes, (4 days at Stâna de Vale) (fig. 4). The favourable period for summer days
decreases with the rise of altitude, so that at low altitudes it lasts from March until
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