Open-Source Numerical Model

An analytical approach emphasized as part of the GLEON CDI is numerical simulation (also called “Water Quality Modeling”).  Numerical simulation has long been the domain of engineers, requiring specialized skills to obtain and format the data necessary to drive the models, deep domain knowledge to adjust the many model parameters, and strong programming and quantitative skills to calibrate the models and manage/interpret the model output. Furthermore, some of the better numerical models are not open source, thus inhibiting their broad acceptance in the scientific community and discouraging the development of supporting technologies to automate their use and application. Through the GLEON CDI, we bring numerical modeling to the broader GLEON community. As described below, we are developing an open-source hydrodynamic-water quality model that conforms to ‘standardized’ data input/output, as well as ‘standardized’ communication between model components. We also deliver water quality simulations to distributed compute resources.

In order to pursue the aims of the larger project it is necessary for us to freely adapt and develop hydrodynamic models including 1D and 3D codes, and so we have been pursuing open-source hydrodynamic model options as freely available ‘drivers’ for the water quality model being developed. Based on our detailed review of model platforms available, we have chosen several hydrodynamic codes as being relevant to the larger CDI system, and a key 3D model chosen is the open-source code GETM. To date we have setup GETM on one lake in the GLEON network, Lake Kinneret.

New flexible WQ modeling library design

The short-term and long-term requirements of the lake ecological models are diverse. After significant consultation and review of available approaches that are currently adopted throughout the lake modeling community, a new model library design has been developed. Our new model, termed the ‘aquatic ecodynamics’ model library, has been designed as a flexible and modular solution to meet the diverse needs of the project and the wider modeling community. Further details of the framework are provided as schematic Figures (1-3). The framework was presented to an international lake ecosystem modeling workshop in Sep 2010:

Hipsey, M.R. Hanson, P. and Hamilton, D.P., 2010. Aquatic ecosystem modelling: a new framework for moving forward in the 21st century. Presentation at the 2010 Lake Ecosystem Modelling Workshop, Silkeborg, Denmark.

GLEON CDI model water quality lake hydrodynamic

Figure 1: Schematic outline of relationship of water quality model to a diverse range of lake hydrodynamic models.

GLEON CDI Aquatic Ecodynamics Model Library AEDML module modules

Figure 2: Outline of key modules and their relationships in the Aquatic Ecodynamics Model Library (AEDML).

GLEON CDI model coupling static hydrodynamic one-way

Figure 3a: Structural elements associated with the coupling between AEDML and various hydrodynamic models. Static (‘one-way’) coupling is indicated here.

GLEON CDI model coupling AEDML hydrodynamic dynamic two-way

Figure 3b: Structural elements associated with the coupling between AEDML and various hydrodynamic models. Dynamic (‘two-way’) coupling is indicated here.