Abstract
The aim of this paper is to investigate the trends and shifts of the circulation types over Romania for 50-year period (1961–2010) on seasonal basis. In order to achieve this, two objective catalogues, namely GWT and WLK, from COST733 Action were employed. Daily circulation types were grouped according to the cyclonicity and anticyclonicity and were used to calculate the seasonal occurrence frequency of cyclonic and anticyclonic types. The trend of seasonal time series was investigated by using Mann–Kendall test and the shifts points were determined by using Pettitt test. The results reveal that the occurrence frequency of anti-cyclonic types increases in summer and winter seasons and the occurrence frequency of cyclonic ones decreases for the summer season (for alpha = 0.05).
Highlights
The atmospheric circulation is the principal factor that determines the climate variability in Europe and in Romania
For the evaluation of air circulation over Romania, 18 262 cases that correspond to daily circulation types between 1 January 1961 and 31 December 2010, were analyzed
For the WLK circulation types the highest occurrence frequency of cyclonic types was obtained for spring and the highest occurrence frequency of anticyclonic types was obtained for autumn
Summary
The atmospheric circulation is the principal factor that determines the climate variability in Europe and in Romania. A variety of subjective or objective methodological approaches were applied for atmo-spheric circulation classification (Huth et al 2008, Philipp et al 2010). A few recent studies have reported considerable changes in the 1980s and 1990s in the persistence of air circulation over Europe for zonal circulation in winter (Werner et al 2000) and for all circulation types in summer (Kyselý 2002). One important application of circulation type classification is to quantify past, present, and future in the atmospheric circulation in terms of frequency and persistence (Huth et al 2008)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
