DRY SPELLS IN THE BRAZILIAN CERRADOS REGI ON - FREQUENCY AND PROBABILITY OF OCCURRENCE

An analysis of daily precipitation data from 100 pluviometric stations in the Brazilian ''cerrados'' (savanna-like vegetation), using histor ical series of 20 or more years, was utilized to identify dry spells o f 10, 15 and 20 days. This information of the frequencial analysis was arranged using the Geographical Information System. The occurrence pr obability of dry spells, estimated by the distribution function of Gum bell & Weibull using recurrence intervals of 5 of 100 years, allowed i dentification of risk periods for conventional agriculture (nonirrigat ed). Therefore, it was possible to make a global analysis of this clim atic problem, which is critical for the agricultural production in the Brazilian ''cerrado'' ecosystem.