Abstract:
A study of the fogs at Sofia, Bulgaria is carried out by the means of proposed Cherni vrah-Sofia Stability Index. By measuring the strength of static stability of the atmospheric layer over Sofia, this index depends only on the surface air temperatures at stations Sofia, Mladost and Cherni vrah and hence it is potentially useful in operational practice. By using the standard weather observations during 01/01/1992-17/12/2014 period, a simple statistical relationship between our index and horizontal visibility in Sofia is established. It is statistically correctly found that while the fogs in Sofia correspond to higher values of the index, the absence of fog favours the lower index values. This general conclusion is supported by a case study investigation of the typical for Sofia fog episode.