Abstract. An 8-year climatological analysis (1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996) of lightning network data over Belo Horizonte, a large city located in Southeastern Brazil, and nearby surrounding areas has indicated a significant enhancement of approximately 100% in the negative flash density and of 50% in the positive flash density over and downwind of the city, compared with the other adjacent areas. A decrease of 25% in the percentage of positive flashes was also observed over and downwind of the city. No urban effect was evident in the peak current of both negative and positive flashes. These results are in agreement with the recent results obtained by Steiger et al. (2002) for Houston, except that the strength of the effect is twice larger than in Houston. The reason for this difference is not clear.

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About 160,000 strokes recorded in the state of Minas Gerais in the summer season of 1993 were analysed in terms of the dependence of the peak-current stroke intensity and stroke density on altitude and ground conductivity. Preliminary results will be presented and discussed in the context of measurements made in other countries.