TITLE:
A Structural Overview through GR(s) Models Characteristics for Better Yearly Runoff Simulation
AUTHORS:
Safouane Mouelhi, Khaoula Madani, Fethi Lebdi
KEYWORDS:
Time Step; Runoff-Rainfall; GR(s) Models; Yearly; Monthly; Daily
JOURNAL NAME:
Open Journal of Modern Hydrology,
Vol.3 No.4,
October
7,
2013
ABSTRACT: In rainfall-runoff modelling, a monthly timescale and an annual one are sufficient for the management of deductions. However, to simulate the flow at a large time-step (annual), we generally precede the use of a model working for a finer time-step (daily) while aggregating the desired outputs. The finest time-steps are considered, apriori, as the most performant. By passing from one time-step to another, and in order to work in the desired time-step (annual) and calculate the potential gains or loss, this article proposed a comparative study between the aggregation method of outputs of a modal working at a finer time step, and a method in which we use a conceived model from the beginning. To ensure this comparative and empirical approach, the choice has been focused on (GRs) models to a daily time-step (GR4J), monthly time step (GR2M) and annual time step (GR1A). The modelling platform used is the same for all three models taking into account the specificities of each one: the same data sample, the same optimization method, and the same function criterion are used during the construction of these models. Due to the moving between these time steps, results show that the best way to simulate the annual flow is to use an appropriate and designed modal initially conceived to this time step. Indeed, this simulation seems to be less effective when using a model at a finer time-step (daily).