About BETR Global
BETR Global is a geographically explicit global-scale multimedia contaminant fate model. The version of the model hosted on this site is coded in Visual Basic for Applications (VBA) and runs within Microsoft Excel with a graphical user interface. BETR Global has been developed and tested on 32-bit versions of Excel 2007 & Excel 2010. There are known incompatibilities between BETR Global 2.0 and Excel 2003 and the 64-bit version of Excel 2010.
Download and installation
The model and the DLL file that is required to generate visualizations of the outputs can be downloaded here as a zip archive. BETR Global is distributed under the GNU Public License. The program is free software. You are free to modify the source code, which is readily accessible through the Visual Basic Editor of Excel. The program is distributed with the hope that it will be useful, but without any warranty.
The model does not require any type of installation, but by default it assumes that all files are located in the directory C:\BETR\. Therefore, it is recommended that you extract the two files in the archive to C:\BETR\.
The two files in the zip archive are:
1) BETR Global V2.0.xlsm
This is the model and associated databases of environmental and chemical information. It is a macro-enabled Microsoft Excel spreadsheet. It has been developed and tested using Microsoft Excel 2007. For the model to operate, you must enable the macro functions of Excel 2007. Instructions for how to enable macros in Excel 2007 can be found here.
2) VbNc.dll
This is a pre-compiled dynamic link library (DLL) for Windows that was developed by Alexander Bruhns. You can read more about it at his website, NetCDF for Excel. BETR Global calls VbNc.dll to write outputs in NetCDF format. The NetCDF (.nc) files generated by BETR Global can be visualized as global maps using the Panoply data viewer provided by NASA. Other viewers for NetCDF data are also available, but BETR Global was developed using Panoply so it is recommended.
Researchers may be interested in the flexible implementation of the BETR contaminant fate modeling framework coded by Harald von Waldow, BETR-Research. BETR-Research is open-source software written in Python, and comes parameterized identically to BETR Global. It can be downloaded here.
BETR Global tutorial
After you download BETR Global and extract the files to C:\BETR\, we recommend you follow these example calculations. This tutorial will take between 1 and 2 hours to complete, and it will give you experience doing both steady-state and dynamic calculations using BETR Global and visualizing outputs using Panoply.
Environmental parametrization
Visualizations of environmental parameters in the BETR Global database including temperature and circulation patterns in the atmosphere and oceans can be found here.
References and further information
Scientific papers and reports describing the BETR Global and its application to various chemical pollutants can be found here. If you are trying to modify the model code or interpret detailed model outputs, you should consult the page describing the model's structure and naming conventions.