FREQUENCY AND TREND OF THE PRECIPITATION AMOUNTS OF THE RAINY PERIODS LASTING 2-4 DAYS, IN MARAMUREŞ, ROMANIA.

The paper analyzes the frequency and trend of the rainfall amounts of the rainy periods lasting 2, 3 and 4 days, which occurred at 4 weather stations in MaramureŠ County, in the period 1961-2016. The homogeneity of the daily data set has been analyzed, using the methodology described by Wijngaard et al. (2003), based on Pettitt, Standard normal homogeneity, Buishand and von Neumann tests, at the 99% significance level and for the frequency analysis, HYFRAN software was used. Subsequently, the frequency of the precipitation amounts of the mentioned periods was calculated, using the method of equal intervals. The cumulative amounts in 2-day intervals show the highest frequency for Class 1 (0.2-6.5 mm), with a probability of occurrence of 45-55%, the cumulative amounts in 3 days for Classes 1 (0.4-7.4 mm) and 2 (7.5-14.5 mm), with a probability of 22-37%, and the cumulative amounts in 4 days for Class 2 (9.9-17.8 mm), with a probability of 21-30%. The decadal distribution of periods accumulating exceptional amounts of precipitation, ≥50 mm, was then analyzed and it was established that the maximum risk interval of their occurrence is June-September. The frequency, trend, degree of assurance and variability of the maximum annual rainfall quantities of the mentioned periods were also studied. The return periods of maximum annual rainfall quantities registered in 2-4 days are ranging between 29.8 and 580 years. [ABSTRACT FROM AUTHOR]