Joint International Conference on Long-term Experiments ...

THE FREQUENCY OF DAYS WITH DIFFERENT TEMPERATURES IN THE
CRISUL REPEDE HYDROGRAPHICAL BASIN
Ana Cornelia Moza
University of Oradea, Faculty for Environmental Protection
ABSTRACT
The particularities of the air temperature’s regime are indicated by a series of elements,
calculated or extracted graphically from the four stations histograms. Some of these
elements are: frequency of frosty nights, frequency of frosty days, winter days, summer
days and tropical days. These elements were analyzed during 1970-2005 at all 4
stations.
INTRODUCTION
The air temperature presents a series of particularities: depending on the altitude,
described by the decrease of the air temperature with the rise of altitude, and depending
on the orientation and the gradient of the slopes, described by their different warming.
While describing the climate of a region, the focus is on monthly and annual
frequency of days and nights over or under certain characteristic limits, represented in
number of days.
Over the year, the air temperature drops below or rises above certain limits,
according to which there were assigned frosty nights, frosty days, winter days, summer
days and tropical days.
MATERIAL AND METHOD
In order to point out the characteristics of the temperature, the data during 1970-2005
were used, obtained from the observations made at the four meteorological stations
(Oradea, Săcueni, Borod, Stâna de Vale), situated both in plain areas and mountain
areas, so that they cover the entire researched area.
The number of days with certain temperatures is extracted from the meteorological
tables for every month. Adding the respective values and dividing the result to the
number of months in the investigated years, we obtain the average number of days in a
month with characteristic temperatures, which is graphically represented by bars.
RESULTS AND DISCUSSIONS
1. The frequency of frosty nights
In the cold season, the nocturnal cooling reaches the highest values, so that the
minimum air temperatures may drop below -10ºC, situation in which the nights are
considered frosty.
In the Crisul Repede hydrographical basin, the frequency of frosty nights rises
directly proportional to the altitude from 11-12 cases in Săcueni, Oradea, up to 52 cases
in Stâna de Vale ( because of the flow of cold air from surrounding peaks and its
stagnation on the bottom of the depression for several days in a row) (fig.1).
Through out a year, frosty nights are recorded at Stâna de Vale meteorological
station from October until April, while at the other stations (Borod, Oradea, Săcueni)
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