Precipitação Máxima Provável no estado do Tocantins: primeira aproximação pelo método estatístico de Hershfield

Abstract

Probable Maximum Precipitation (PMP) is defined as the biggest rain depth that is meteorologically possible to occur over a given region, associate to different duration time, without taking into account the long-term climate trends. This study aimed to obtain and spatialize the PMP for the Tocantins State, associated with twelve intervals of duration, between 10 and 1440 minutes, based on the Hershfield methodology. To proceed with the PMP mapping, the inverse-power-distance interpolator, considering as exponent 2, 3 and 5, was used, evaluating the following statistical precision: bias and mean average percentage error, both performed from the cross validation procedure. For the greatest rain duration time (1440 min), the PMP ranged from 411 to 768 mm, and for the smallest duration (10 min), the PMP ranged from 63 to 105 mm. In general, the PMP in the Tocantins State showed the biggest values in Bico do Papagaio (north) and southwest regions of the State. The inverse-square-distance presented the best performance among the interpolators tested for the PMP spatialization, with estimation errors considered acceptable.