Evaluation of points of vulnerability caused by the solar action in a drainage micro basin in the semiarid of Paraíba

Abstract

Points of vulnerability caused by the solar action had been evaluated in a drainage micro basin in the semiarid of Paraíba, during a translation from October, 2003 to September, 2004 in the “Estação Experimental Bacia Escola – CCA/UFPB”, in São João do Cariri-PB. Five points of determination in a toposequence had been defined and they had been analyzed according to: meteorological variables, potential evapotranspiration and dendrometry. The biggest incidence of global solar radiation, reflected radiation, absorbed radiation and insolation, had been verified in August, September, October, November and December, coinciding with the months of bigger taxes of evapotranspiration. The amplitude of annual variation of the cloudiness in the region is relatively small, varying from 5 to 8/10 during the year. It is advisable not to leave the soil uncovered, since the erosive factors are more intense in such situation. Key words: drainage micro basin, toposequence, vegetal cover, meteorological variables, erosion