Calibración y aplicación del índice de aridez de De Martonne para el análisis del déficit hídrico como estimador de la aridez y desertificación en zona áridas

modelling aridity and determining the hydrologic balance are necessary in the planning of the use of water resources, particularly in areas with limited water availability. the purpose of this study was to adapt and calibrate the hydroclimatic aridity model of de martonne, modifying it to make it adequate for the study of the water balance in arid and semi-arid areas. a numerical analysis of the aridity index [a = 12pp/(t + 10)] was carried out in order to detect its sensitivity to rainfall and temperature gradients, where a is the aridity index of de martonne, pp is the monthly rainfall, and t is the average monthly temperature. a least squares analysis was used to select a polynomial function numerical model where x1 is the average temperature, x2 is the monthly rainfall, and a amod = f(t,pp) function is satisfied. the modified equation was assayed and correlated using data from weather stations located in the watersheds of la paz and comondú, baja california sur. la paz presented a monthly average index of 4.96, and comondú recorded a value of 5.16. the equation of the fitted model was idha = 0,176012 + 0,101391 * pp, where idha is the hydro-environmental availability index and pp is the monthly rainfall, with r2 = 94.83% and r = 0.97 indicating a close relationship between pp and idha. the modification applied to the de martonne index was numerically functional, with a high potential of application to hydrological studies of arid and semi-arid areas.