Meteorological drought characterization using severity-areafrequency curves, in San Luis Potosi Valley of Mexico

Abstract

This work is composed of three sections. The first briefly discusses general ideas about droughts, including definitions and types. The second section provides a detailed presentation of the procedure suggested to estimate severity-area-frequency curves (SAF). The third part describes a numerical application for the valley of the city of San Luis Potosi , Mexico. The
proposed sequence consists of five basic stages: (1) compilation and selection of records to be used, (2) spatial interpolation of records, (3) calculation of annual rainfall deficits, (4) probabilistic processing of annual deficits and (5) construction of SAF curves. The temporal and spatial characteristics of the droughts are essential to understand their behavior and evolution in a watershed or specific region. The procedure for a regional estimation of the SAF curves was established using one of the simplest indices to characterize droughts and a basic spatial interpolation technique. This included the use of the generalized extreme values
distribution to obtain predictions that define the frequency of these curves. Lastly, conclusions are formulated which point out the usefulness of SAF curves to compare droughts between regions and to interpret years of historical drought. The simplicity of the proposed method is also shown and the first stage is indicated as the most critical.