Getting Started


The model is available pre-compiled for windows, linux and macintosh operating systems with several test-cases available from the Downloads tab. Source code and compilation instructions are available, accesible via our GitHub repository.


No specific installation steps are needed if you are using the precompiled binaries. Simply ensure the glm executable program file is in an accessible folder and the provided support dll’s are co-located in this folder.

Overview of Model Operation

The GLM simulation requires several “namelist” (nml) text files that described the model as outlined in the below figure. The model requires csv files for boundary conditions of meteorology and inflow/outflows

Model Operation

The model comes with a built-in plotting library that works on both windows and linux versions in addition to detailed outputs provided in NetCDF format, and the option to create custom csv output files. When the model is invoked with the plotting library called then a window will open and plot the model outputs in real-time as the model is running. For more info on plotting, see below.

Model Configuration

A GLM simulation is configured via the main “namelist” (nml) text file called glm2.nml. The key elements of this dile are depicted in the above image and summarised in detail in the below table.

The first block is compulsory, with the following variables that may be set :

Variable Name Description Type Options Default
sim_name title of simulation [string] 'lake'
Layer properties
max_layers maximum number of layers [integer] 500
min_layer_vol minimum layer volume (m3 * 1000) [real]
min_layer_thick minimum thickness of a layer (m) [real]
max_layer_thick maximum thickness of a layer (m) [real]
Light properties
Kw background light attenuation (/m) [real]
Mixing parameters
coef_mix_conv mixing efficiency - convective overturn [real]
coef_wind_stir mixing efficiency - wind stirring [real]
coef_mix_shear mixing efficiency - shear production [real]
coef_mix_turb mixing efficiency - unsteady turbulence effects [real]
coef_mix_KH mixing efficiency - hypolimnetic Kelvin-Helmholtz turbulent billows [real]
coef_mix_hyp mixing efficiency - hypolimnetic turbulence [real]
deep_mixing title of simulation [boolean] T/F .true.
Other options

EXAMPLE: &glm_setup sim_name = 'ALake Simulation' max_layers = 500 min_layer_vol = 0.025 min_layer_thick = 0.50 max_layer_thick = 1.500 !-- Light Parameters Kw = 0.6 !-- Mixing Parameters coef_mix_conv = 0.125 coef_wind_stir = 0.23 coef_mix_shear = 0.20 coef_mix_turb = 0.51 coef_mix_KH = 0.30 coef_mix_hyp = 0.5 ! non_avg = .true. ! deep_mixing = .true. ! mobility_off = .true. /











Example glm2.nml file configured to run a variety of GLM model setups is available on the examples page.

An example glm.nml file configured to run a simple GLM model setup (v1.4) is available below:

GLM control file -> (English version, please rename to glm.nml for use).

GLM control file -> (Español version, please rename to glm.nml for use).

Running the model on windows:

To run the model on windows you can make use of a file called “glm32.bat" or "glm64.bat” in the simulation directory to automate the running command. Within the bat file, make sure is setup correctly and points to the appropriate “bin” folder where the exe and dlls are located on your system. For example:


or if the in built plotting library is to be used then invoke the xdisp command line argument:

..\bin\glm32\glm.exe --xdisp

Running the model on linux:

To run the model on linux simply call the executable form your working simulation directoty. For example:


or if the in built plotting library is to be used then invoke the xdisp command line argument:

../bin/glm --xdisp

A simple tutorial on running GLM with the example simulations is available:

Remember to watch out the date format when you create or re-save a meteorological or inflow boundary condition csv file from Excel. Excel changes the date format to be its preferred style instead of the style that GLM requires YYYY-MM-DD so you must be sure to set that manually in the cell format properties of Excel before saving csv files.

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