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The paper analysis the precipitations associated to the cut-off lows and their regional distribution induced by the air circulation types and the position of cut-off lows in relation to the different regions of the country, in Romania in 2014. Cut-off lows have been identified using geopotential, air temperature and circulation maps at 500 and 300 hPa levels within the region of latitude 40 to 50 °N and longitude 15 to 35 °E. To establish the atmospheric circulation type for each cut-off event, HYSPLIT model was used (Draxler and Rolph, 2012). Based on the daily precipitation data for the year 2014 from 150 meteorological stations from Romania, divided into historical and geographical regions, the total amount of precipitation for each cut-off low event was determined. It was also calculated the monthly and annual amount of precipitation for each weather station and the ratio between the monthly (and annual) amount of precipitation and those associated to the cut-off lows. The most important findings are: 13 cases of cut-off lows were identified, the highest number in July (3 cases); in most of the cases the cut-off lows lasted for 2 days (5 cases), the longest case having 8 days; the most significant amounts of precipitation were recorded in May and April, and the highest value recorded exceeded 100 mm (125.7 mm in Banat region); masses of air reach in moisture advected from the south (S, SV, SE) and west (V, NV), recorded a high frequency; high percentages of precipitations induced by cut-off lows from the total rainfall of the year were recorded in the regions situated in the south, east, south-west and west part of Romania as a consequence of air circulation types generating cut-off lows existence. [ABSTRACT FROM AUTHOR]

The paper analyzes some characteristics of annual and seasonal amounts of rainfall recorded in 24 hours in Romania. Annual and seasonal frequency distribution of rainfall quantities registered in 24 hours, air circulation type regarding these events, and the return periods of the absolute maximum values have been analyzed. Annual and seasonal values of maximum 24-hour precipitation amount from 23 weather stations from Romania, located between 3 and 661 m, have been considered over a period of 55 years (1961-2015). First, the data sets were tested using homogeneity distribution test at 99 % of significance level provided by XLSTAT software. HYFRAN software and HYSPLIT model have been employed in order to calculate statistics based on frequency analysis and to identify the atmospheric circulation type, respectively. The main findings are: absolute maximum annual rainfall quantities vary between 65.3 and 224.0 mm, with the highest values (over 120 mm) in the east and south-east part of the country; most of the weather stations have the highest annual frequency between 25- 50 mm, while winter, spring, and autumn are characterized by high frequency of 0-25 mm amounts; for the winter season, the maximum 24-hour precipitation has never exceeded 75 mm, in spring and autumn they are under the 125 mm threshold, while in summer locally exceeded 200 mm; the return periods of maximum annual quantities of rainfall are generally ranging between 32.2 and 387 years, highlighting the continental climate of some regions of the country; four types of air circulation have been detected, more frequent from south and southwest part of the Europe, bringing warm and moist air masses. [ABSTRACT FROM AUTHOR]