Application of the ‘Hess-Brezowsky’ Classification to the Identification of Extreme Precipitations in Northern Part of Moldova

Due to climate change, important attention was paid to the precipitations amounts over Moldavia's northern part. To point out the rainy air-circulation types was used the ‘Hess-Brezowsy’ Grosswetterlagen system (HBGWL) with 29 types of classifying European synoptic regimes of the 2000 to 2018 period at the reference weather stations of Bacău (184 m), Botoșani (161 m), Ceahlău-Toaca (1897 m), Iași (102 m), and Suceava (350 m). The highest amounts of precipitations annually from 2000 to 2018 in Romania's northeastern part were associated with the retrogressive cyclones. Therefore, on a background of the northeastern, cyclonic type (NEZ), there were recorded 53.45 mm, followed by High Scandinavia-Iceland, the ridge over Central Europe (HNFA), with 48.14 mm, and those from East in cyclonic type, with 44.03 mm. All the high over Central Europe (HM) weather types were associated with the lowest precipitations, only 1.71 mm. Also, small amounts of precipitations in the southwestern and south background, both of them into an anti-cyclonic type (SWA, SA), with 2.56 mm, respectively, 2.92 mm. Semestrial, the most important amounts of precipitations in the northeastern part of Romania were attributed to the retrogressive cyclones in the Eastern part of Romania and the ridges over the northern part of Europe. So, associated with EZ, during the 2000 to 2018 period, in the cold semester were recorded 28.43 mm and 27.66 mm within NEZ. During the warm semester, the highest amounts of precipitations were recorded within the HNFA type, with 42.75 mm, followed by Highs over the British Isles (HB) – 25.44 mm. The lowest values were associated with the southerly and southwesterly, both into an anti-cyclonic type (SA, SWA).