BATISTA, M. S.; http://lattes.cnpq.br/5476987432541216; BATISTA, Myrla de Souza.
Résumé:
The main purpose of hydrologic modelling is the simulation of the water cycle
processes. These processes are complex owing to their variability, particularly at large
river basins. Distributed models which may consider these variabilities of the system have
been designed recently. However, even with such models the simulations contain
uncertainties due to the parameterization, poor quality data, model structure and model
user. In this sense, this research intend to analyze the uncertainties in the simulated runoffs
at various catchments in the upper Paraíba river basin, with the distributed model NAVMO
considering different basin divisions and databases, an aspect not yet investigated
regionally. The analyses were carried out in relation to previous work with the model,
calibrated for the region divided into 61 sub-basins and used to simulate long-time series of
runoff with other basin divisions (10, 21, 31 and 40) and four databases consisting of 16,
18, 35 and 80 rainfall stations. In addition, the sensitive parameters of the model were
calibrated with the region divided into 31 sub-basins and used to simulate long-term time
series of runoff with other basin divisions (10, 21, 40 and 61), which served as the basis for
investigating the uncertainties in the simulations, and for comparisons. The investigations
were carried out by analyzing the statistical properties of the simulated series such as: the
sum of annual simulated values, the double mass curve, the coefficient of determination,
the sum of squared differences, the parametric t-test and F-test, the Wilcoxon test and
fitting typical distributions of probability (e.g., Gama, Pearson III, Normal, Gumbel and
GEV). The results showed that the simulations were sensitive to the basin divisions, model
parameterization and rainfall data. In addition, the uncertainties decreased as the number of
basin divisions and quality of the rainfall data increased. Moreover, the results were
affected by the model structure in relation to the drainage system and rainfall database,
which vary depending on the division of the region.