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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]

This paper analyzed the spatial and temporal variability of the rainy periods that occurred in the county of Maramureş. In this regard, daily precipitation data have been used from 4 weather stations, for the period 1961-2013. In the first stage the homogeneity of the daily data set has been analyzed, based on Pettitt, Standard normal homogeneity, Buishand and von Neumann tests, at the 1% significance level. The analyzed data belonged to Class 1 („useful"), as they reject the null hypothesis of 3 out of the 4 mentioned tests. Subsequently, the annual, monthly and seasonal number of rainy periods has been analyzed, the length of the periods, their frequency depending on length and their spatial and temporal variability. Based on the CurvExpert 1.37 program, the trend of the annual number of rainy periods depending on their duration was studied. The result was a total number of over 8100 periods, for the 4 stations. The number of rainy periods increases from the west to the east, once with the growth of land altitude. During a year may occur, on average, between 37-40 periods with an average length of 4-4.5 days. The length of the rainy periods varies between 2-35 days. The most periods are recorded in the intervals May-July and December-January. The most periods lasting ≥ 10 days, occurred in the decade 2001-2010 or 1961-1970. [ABSTRACT FROM AUTHOR]