Global NEWS modeling Environment (GNE) and NEWS 2

NEWS 2

NEWS 2 is the latest version of the Global NEWS model. A full description of the overall structure and the nutrient form sub-models will be provided in a manuscript currently under review (Mayorga et al.) and another manuscript currently in press (Seitzinger et al., Global Biogeochemical Cycles). These manuscripts will be available soon from the Publications page in this web site.

GNE Overview

GNE (Global NEWS Modeling Environment, pronounced as "genie") is a code package that brings together all Global NEWS sub-models into a common framework. Specifically, it implements the NEWS 2 model. It also provides basic functionality for standard pre-processing of gridded GIS data to create basin-aggregated values for use in a model run. With GNE, anyone can run all the models, with choice on input data to use, output variables to export, models to run, etc.; individual nutrient forms can be run all at once or separately.

GNE is written in Python, a free, open source programming language available on all major operating systems. Model equations are largely coded using the NumPy add-on, which provides a simple array syntax similar to Matlab. While a key strength of Python is that itís fairly easy to learn and understand, no programming whatsoever is required to simply run the models; changes to the code will generally only be needed when modifying the underlying model equations and core coefficients.

GNE is also a generic Python framework that can be used to implement any lumped basin model that uses basin-aggregated input variables and outputs basin-aggregated variables. Model inputs and outputs are stored in simple (ASCII) text tables (CSV, or comma-separated variables format) that can be easily viewed in a spreadsheet program like Excel.

Audience and Documentation

The GNE User Manual and Introduction presentation described below are focused on Model Users rather than Model Developers or GNE Developers. Model Users only need to learn how to setup or change a model run using a set of text configuration files, and to organize input and output files in a regular, structured fashion. Python skills are not required. See the User Manual for more details on GNE user types.

The GNE User Manual (pdf) describes the NEWS 2 model implementation in GNE, focusing on Model Users. It includes extensive descriptions, instructions on running GNE at the command-line and sending run-time messages to log files, description of GNE components (folder organization, configuration and code files, input and output data), sample configuration files, complete descriptions of configuration file usage and syntax, Python and GNE installation instructions, a listing of Python online resources, and an overview of modeling steps and conventions as used in the Millennium Ecosystem Assessment scenarios project. The GNE Introduction presentation (powerpoint) provides a general overview of GNE, its functionality, code and data file organization, and usage. It complements the User Manual in providing a broader and more visual presentation.

See the User Manual also for links to Python and NumPy resources (appropriate versions, installation files, tutorials, use in scientific applications, etc), and brief installation instructions for GNE. Note that the GNE component that does "GIS pre-processing" (takes GIS rasters and creates basin properties) relies on ESRI ArcGIS geoprocessing and won't work if ArcGIS 9+ is not installed.

Some additional details on GNE and NEWS 2 are currently available at the CSDMS model repository.

Availability, Use Restrictions, and Contact Information

NEWS 2 model code consistent with the terminology presented in Mayorga et al. (in review), together with sample configuration and input and output files for the year 2000, are available here as a zip file, GlobalNEWS2model.zip (2.6 MB); see the included README.txt file first before using the NEWS 2 code and files. An earlier version of the model code was used to produce the results described in Mayorga et al. (in review) and Seitzinger et al. (in press).

The NEWS 2 model and GNE were developed by the Global NEWS group. We encourage its use for research and educational (non-commercial) purposes, but we request that active users contact us to inform us about how it is being applied. Such feedback and reporting will improve our continued development of the model code. Global NEWS is a work group of UNESCO's Intergovernmental Oceanographic Commission (IOC).

Use of NEWS 2 should be ackwnowledged by citing Mayorga et al (in review); Beusen et al. (2009) and Billen and Garnier (2007) should also be cited if the DSi model and the ICEP index, respectively, are also used.

For questions and additional information, please contact:
Emilio Mayorga, Ph.D. mayorga@apl.washington.edu
Applied Physics Laboratory, University of Washington, Seattle, WA USA