Some aspects of the wind ‘Koshava’ in the lower troposphere over Belgrade

Abstract

‘Koshava’ is a gusty wind of moderate to strong intensity, blowing from a south-easterly direction, over Serbia, Romania and Bulgaria. It is caused by the interaction between the synoptic circulation and the orography of the Carpathian and the Balkan mountains. This paper analyses wind data from an area where the influence the ‘Koshava’ wind is high during periods of maximum duration of ‘Koshava’. The focus of the paper is the examination of urban and suburban effects on ‘Koshava’ and the correlation between the instantaneous maximum wind speed and the hourly mean values. Various empirical distributions are fitted to the daily maximum wind speed and the best fit for each season and site is proposed. The vertical structure of the lower troposphere above a suburban site during the longest period of consecutive days of ‘Koshava’, which occurred in January and February 1972, is considered.