Scientific Secretary of the National Institute of Meteorology and Hydrology,
Bulgarian Academy of Sciences - Bulgaria
Lightning is yet little understood, weather events on this planet. It is generated by the breakdown of electric fields in thunderstorm systems through discharges that can be cloud-to-cloud, cloud to ground or cloud-to-air.
Forecasting lightning has been described as trying to predict the impossible but, even so, general risk forecasts are produced on the basis of observed lightning activity, radar data, models, etc.
One of the greatest expectations are associated with the understanding of the thunderstorm electrical phenomena. There are different approaches and the present work will be dealt mainly with one of them-the inductive mechanism. During the last years the laboratory research show that the inductive mechanism for thunderstorm electrification (Proposed by John Mason 1968) including the interaction of water droplets with hailstones, leads to a considerable electric charge separated. The further model estimation has showed the significant role of the inductive mechanism in the last stages of the thunderstorm development.
The aims of the present work are to investigate the contributions of each one of the main cloud parameters to the change of the electric field intensity in the convective cloud, on the base of the inductive mechanism, using the Mason's model as a numerical tool for estimating these changes.
Reports in 2001 from the Intergovernmental Panel of Climate Change (IPCC), claimed that the produced carbon dioxide was already warming up the world and that if nothing was done it would have all sorts of disastrous consequences. There had been a slight increase in the temperature on the ground. But satellite measurements showed, that higher up in the so-called "free troposphere", things didn't seem to be getting much warmer. Anyhow, the status of the free troposphere became a very big deal. It is well known that the troposphere conditions determine the severity of the convective clouds. In this direction has been performed a special regionally study of the Sofia locally trends of the free troposphere balloon measured parameters. It will be of great profits to clear up the variability of the meteorological conditions and to be improved our understanding of the local peculiarities in the troposphere in a respect of the global variations.
It has been investigated the magnitude changes of the temperatures, dew point temperatures at the main isobar standard levels in the troposphere and lower stratosphere over Sofia and their tendency in the last 30 years, influenced by the global atmosphere changes.
On the base of the summary results, the most probably scenarios about the future thundercloud features have been taken in account during the further modeling with the Mason's mechanism. The derived results have been applied to predict a probably lightning activity in the later stages of such kind of thunderstorms. The results can be utilized jointly with noninductive mechanisms for evaluating the whole electric Cloud State basing on their micro and macro characteristics.
S. I. Kolev, C. P. R. Saunders:
Some New Results from Simple Modeling of Thunderstorm Electrification Using the
Inductive Mechanism; Bulgarian Journal of Meteorology and Hydrology, BJMN, Vol. 10, 1999, No. 3-4, pp. 86-93
Staytcho Kolev; 2001:
A PRELIMINARY STUDY OF THE VARIATIONS OF SOME TROPOSPHERE MEASURED PARAMETERS
OVER SOFIA;WMO; RA VI Seminar on Capacity Building and New technologies in Meteorology:
Challenges and Opportunities for the Balkan Countries Sofia, Bulgaria, 11-13 October 2001
Part of this work was supported by the Joint Agreement between The Royal Society of London and the Bulgarian Academy of Sciences.