Um estudo de downscaling dinâmico de precipitação intrasazonal acoplado a modelo chuva-vazão na bacia hidrográfica alto-médio São Francisco

Abstract

RESUMOEste estudo mostra a aplicação de modelagem hidroclimática dinâmica (hydroclimate downscaling) de precipitação acoplada a um modelo hidrológico chuva-vazão, para as Bacias hidrográficas denominadas Cachoeira Manteiga e Porto da Extrema, localizadas na Bacia do Alto-Médio São Francisco no Estado de Minas Gerais. Ênfase foi dada à simulação na escala intrasazonal (mensal). Os resultados sugerem que a simulação de precipitação pode ser usada como variável de entrada em modelos de estimativa de vazão para períodos na escala de um mês, dando subsídio a um melhor aproveitamento dos recursos hídricos na bacia hidrográfica estudada. Estes ainda sugerem que a simulação de precipitação, quando corrigida pela técnica Probability Density Function (PDFs), é mais eficiente na estimativa de precipitação simulada quando comparada com a precipitação observada na bacia, resultando em uma melhor simulação de vazão afluente na bacia. Palavras-Chave: Simulação hidroclimática, modelo chuva-vazão, bacia hidrográfica. ABSTRACT: A STUDY OF INTRASEASONAL PRECIPITATION DYNAMIC DOWNSCALING COUPLED TO RAIN-STREAMFLOW MODEL AT THE ALTO-MÉDIO SÃO FRANCISCO HYDROGRAPHIC BASIN.This study shows the use of rainfall dynamic hydroclimate downscaling coupled to the rain-streamflow hydrological model for the hydrographic basins named Cachoeira Manteiga and Porto da Extrema, localized at Alto-Médio São Francisco Basin in Minas Gerais State. The emphasis was to simulate the intraseasonal scale (monthly). The results suggest that the rainfall simulation can be used as input data to streamflow estimation models for periods of monthly scale, allowing a more rational usage of the surface water resources in the hydrographic basin studied. It is also suggested that the rainfall data simulation, corrected by the Probability Density Function (PDF) technique, is more efficient to estimate rainfall comparing to observed rainfall in the basin thus resulting in a better simulation of the basin flow outlet.

Thornthwaite’s Climate Regionalization for the State of Tocantins, Brazil

“…The first one quantifies the occurrence of a trend for overestimation or underestimation. Meanwhile, a low MAPE value corresponds to greater the similarity observed value and the one calculated by cross-validation (LIMA; ALVES, 2009). The semivariogram model with the lowest MAPE value was selected to map the climatic indexes.…”

Aplicação do modelo hidrológico SMAP na determinação da produção de água em uma bacia hidrográfica costeira (Application of the SMAP hydrological model to determine water production in a coastal catchment area)

“…It is a conceptual and concentrated model that seeks to represent the storage and water flows in the basin through fictitious linear reservoirs. It is considered a model that requires the obtaining of few parameters and low computational demand (Castanharo et al, 2007, Lima;Alves, 2009). The model uses as input data, the total precipitation and evaporation heights in the desired time interval, the drainage area of the basin and the initial conditions of the basin (Lopes et al, 1982).…”

“…For the study, the hydrographic basin was subdivided into 14 sub-basins and 14 characteristic points and the estimation of the flows occurred through the model of hydrological simulations SMAP implemented in environment MATLAB. Lima and Alves (2009) evaluated the applicability of the SMAP in estimating the average flow for the Cachoeira Manteiga and Porto de Extrema hydrographic basins, located in the Upper São Francisco Basin (MG). In order to do so, it fed the model with simulated precipitation data by hydroclimate downscaling and performed automatic calibration, assuming as its objective the sum of the root of the quadratic error between the observed and calculated flows.…”