2022-07-01 16:01


Conference: Bucharest University Faculty of Physics 2019 Meeting

Section: Atmosphere and Earth Science; Environment Protection

The weather in Romania in asociation with Shapiro-Keyser Mediterranean extratropical cyclones

Mihaela BRÂNCUȘ (1,2), Bogdan ANTONESCU (1,3) and Sabina ȘTEFAN (1)

1) University of Bucharest, Faculty of Physics, P.O. BOX, MG-11, Magurele, Romania

2) Romanian National Meteorological Administration- RMC Oltenia, Craiova, Romania

3) National Institute of R&D for Optoelectronics, Măgurele, Romania


Shapiro-Keyser cyclone, strong winds, heavy precipitation

The Mediterranean cyclones and the associated frontal structures play an important role in the weather and climate of the Romanian territory, especially in the cold season. These cyclones often lead to large social and economic impact due to strong winds or heavy precipitation. In some cases these severe weather events are associated not with cold and warm fronts but with the occluded fronts. Such fronts begin to develop when an extratropical cyclone undergoes stage III of the Shapiro-Keyser conceptual model (Shapiro and Keyser, 1990). A climatology of Shapiro-Keyser Mediterranean cyclones that affected the Romanian territory in the cold season (October–March) was performed over a 10 years period (2008–2018). Surface maps and satellite images were used for the identification of the cyclone cases. A cyclone case was considered to be a Shapiro-Keyser Mediterranean cyclone if its minimum central pressure was less or equal to 1000 hPa and, during the mature stage, the bent-back front formed a spiral visible in the satellite images. During the analyzed period 30 cyclone cases were identified with a maximum of occurrence during 2009–2010 and 2012–2013 cold seasons (5 cases/year). Meteorological data recorded by the national weather stations network were used to analyze the effects (winds and precipitation) over the Romanian territory. The eastern and southern parts of Romanian territory were the most affected regions by the weather phenomena associated with this type of cyclones. Generally, in Dobrogea region were recorded the strongest wind gusts (with a peak of 38 ms-1), while the largest 24 h precipitation amounts were recorded especially in Moldova and Muntenia regions, but the maximum amount of 97.9 mm was in Transilvania region.


(1) Shapiro, M. A., and D. Keyser, 1990: Fronts, jet streams and the tropopause. Extratropical Cyclones, The Erik Palmén Memorial Volume, C. W. Newton and E. O. Holopainen, Eds., Amer. Meteor. Soc., 167–191.