geographia - Studia

T. TUDOSE, F. MOLDOVAN
in the Great Plains, a gradual transition to a maximum during the night is noticeable, while
in the low plains, the maximum is recorded in the morning (at 6 a.m. local time).
Pavai and others (2007), using three-hourly messages from 174 Romanian
meteorological stations for 17 summer seasons (1990-2007), determines the diurnal
variations of the relative frequency of rainfall and lightning discharges. For North-Western
Romania, he identifies a maximum of rainfall during afternoon in the hills, depressions
and valleys, and during late evening in the plains.
This paper tries to establish the monthly and annual diurnal variation of significant
rains, as well as their duration, setting a starting point for the identification of areas where
this phenomenon happens more frequently, as well as for the future analysis of other
parameters (average intensity, highest intensity, torrential nature).
2. DATA AND METHODS
Significant rains are represented by liquid precipitations, torrential or not,
registered by the recording rain gauge during summer season, which meet certain
conditions regarding the average and maximal intensity, and the amount of water fell
(Instructions for meteorological stations, 1995):
- highest intensity > 0.04 mm/minute;
- average intensity > 0.02 mm/minute or a recorded amount of water > 2.5 mm/m 2 .
Month
Met.
station
50
Monthly frequency and summer amount of rainfall recorded at the analyzed
meteorological stations (%)
I II III IV V VI VII VIII IX X XI XII
Table 1
Sum of
period
IV-X
Satu Mare 6.4 5.4 5.7 7.6 10.2 11.8 11.4 10.4 8.8 7.1 7.1 8.1 67.3
Supuru
de Jos
5.5 4.5 5.3 8.7 10.4 14.4 12.1 10.9 8.5 6.1 6.7 7.0 71.0
Baia
Mare
8.1 5.8 6.6 7.4 8.9 10.8 10.0 9.2 8.1 7.1 8.3 9.7 61.5
Sighetu
Marm.
6.2 5.0 6.0 7.7 10.1 12.0 12.5 10.4 9.2 6.8 6.5 7.6 68.7
Ocna
Şugatag
5.7 4.8 6.1 7.7 11.1 12.9 13.3 10.6 8.1 6.6 6.2 7.0 70.2
Cluj-N. 4.6 3.7 4.8 9.3 11.2 14.8 15.3 10.9 8.4 5.5 5.8 5.6 75.5
Dej 6.6 4.7 5.9 8.7 9.7 13.1 11.9 10.4 8.2 6.1 7.0 7.7 68.1
Zalău 5.3 4.3 5.4 8.5 11.5 14.6 12.4 10.7 8.6 5.6 6.6 6.7 71.9
BistriŃa 6.4 4.5 5.3 8.8 9.9 12.9 13.3 9.8 8.9 6.5 6.4 7.3 70.1
Vlădeasa 6.4 5.1 5.6 7.1 9.9 14.2 13.4 10.6 8.9 6.0 6.1 6.7 47.1 *
Iezer 5.6 4.9 6.6 8.7 10.4 12.3 12.1 9.4 8.9 7.9 6.8 6.5 42.6 *
*Sum of period VI-IX
For the study, we used data concerning significant rains from TM 13 annual table
from 11 meteorological stations in North-Western Romania: Satu Mare and Supuru de Jos
(in the plain), Baia Mare, Sighetu MarmaŃiei and Ocna Şugatag (in Baia Mare and Maramureş