Improving the Accuracy of Hydrodynamic Model Predictions Using Lagrangian Calibration

Neda Mardani,Richard Brown,Roy C Sidle,Helen Fairweather,Kabir Suara,Adrian Mccallum

doi:10.3390/w12020575

Abstract

While significant studies have been conducted in Intermittently Closed and Open Lakes and Lagoons (ICOLLs), very few have employed Lagrangian drifters. With recent attention on the use of GPS-tracked Lagrangian drifters to study the hydrodynamics of estuaries, there is a need to assess the potential for calibrating models using Lagrangian drifter data. Here, we calibrated and validated a hydrodynamic model in Currimundi Lake, Australia using both Eulerian and Lagrangian velocity field measurements in an open entrance condition. The results showed that there was a higher level of correlation (R2 = 0.94) between model output and observed velocity data for the Eulerian calibration compared to that of Lagrangian calibration (R2 = 0.56). This lack of correlation between model and Lagrangian data is a result of apparent difficulties in the use of Lagrangian data in Eulerian (fixed-mesh) hydrodynamic models. Furthermore, Eulerian and Lagrangian devices systematically observe different spatio-temporal scales in the flow with larger variability in the Lagrangian data. Despite these, the results show that Lagrangian calibration resulted in optimum Manning coefficients (n = 0.023) equivalent to those observed through Eulerian calibration. Therefore, Lagrangian data has the potential to be used in hydrodynamic model calibration in such aquatic systems.

Highlights

Hydrodynamic models are essential tools for estuarine and coastal management [1] and have been used in studies of water quality [2], sediment transport [3], and predicting the impact of different climatic scenarios on estuaries and coastal waters [4]
Topography, boundary conditions, time steps and modelling discretization and computational errors are the main sources of error that result in uncertainties in the models [8,9,10]
We focused on improving the accuracy of hydrodynamic modelling of estuaries using combined Eulerian and Lagrangian datasets

Summary

Introduction

Hydrodynamic models are essential tools for estuarine and coastal management [1] and have been used in studies of water quality [2], sediment transport [3], and predicting the impact of different climatic scenarios on estuaries and coastal waters [4]. These models play significant roles in flood forecasting, contaminant modelling, and changes to estuaries and coastal morphology [5,6,7]. Simplifying the dimensions and forcing terms to conserve computations [11], and inaccuracies in the input data, such as boundary conditions and bathymetry, can contribute uncertainties

Methods

Results

Discussion

Conclusion