Índice de reconhecimento de secas usando a evapotranspiração potencial diária em região semiárida.

Abstract

The water shortage in the Brazilian semiarid often became a limiting factor for urban, agricultural and industrial development, directly interfering with life and income of people. This study aimed to determine the dry recognition index in northeastern semiarid region, with reference to the daily potential evapotranspiration obtained by the Penman-Monteith method (FAO) and meteorological data observed in the basin of Piancó-Piranhas-Açu for a period 23, these data were acquired in the meteorological station of INMET located in the Irrigated Perimeter of São Gonçalo, Sousa-PB, with this was compared with the methods of Thornthwaite, Hargreaves and Blaney-Criddle, for annual, semi-annual, quarterly and monthly periods . Where its impacts were calculated using statistical methods of Mean Square Error Root and Bias Error Ages. Where nine of the 23 years were detected with dry, semi-annually the most severe drought occurred in the second half, being classified as dry extreme classes, separated by a quarter the last two were more severe droughts, while monthly its contents are very close in their Most of the results equivalent to more years of severe drought, starting in May. The Thornthwaite method was the one closest to the reference method, the most suitable for use in the region, where it is easy pet needing only meteorological data (temperature).