1. Need help? Please let us know in the UMEP Community.

  2. Please report issues with the manual on the GitHub Issues.

  3. Please cite SUEWS with proper information from our Zenodo page.

2. Workflow of using SUEWS#

The following is to help with the model setup. Note that there are also starting tutorials for the version of SUEWS in UMEP. The version there is the same (i.e. the executable) as the standalone version so you can swap to that later once you have some familiarity.

2.1. Preparatory reading#

Read the manual and relevant papers (and references therein):

  • Järvi, L., Grimmond, C. S. B., Taka, M., Nordbo, A., Setälä, H., and Strachan, I. B. Development of the surface urban energy and water balance scheme (SUEWS) for cold climate cities. Geosci. Model Dev., 7(4):1691–1711, August 2014. doi:10.5194/gmd-7-1691-2014.

  • Järvi, L., Grimmond, C.S.B., and Christen, A. The surface urban energy and water balance scheme (SUEWS): Evaluation in Los Angeles and Vancouver. J. Hydrol., 411(3-4):219–237, December 2011. doi:10.1016/j.jhydrol.2011.10.001.

  • Ward, H.C., Kotthaus, S., Järvi, L., and Grimmond, C.S.B. Surface urban energy and water balance scheme (SUEWS): Development and evaluation at two UK sites. Urban Clim., 18:1–32, December 2016. doi:10.1016/j.uclim.2016.05.001.

See other publications with example applications

2.2. Decide what type of model run you are interested in#

Available in this release

SUEWS at a point or for an individual area


SUEWS for multiple grids or areas


SUEWS with Boundary Layer (BL)


SUEWS with snow


2.3. Download the program and example data files#

Visit the SUEWS download page to receive a link to download the program and example data files. Select the appropriate compiled version for your platform to download. There is also a python-based version in UMEP under the QGIS environment. For python users, SuPy - a python wrapper for SUEWS - is also available.

Note, as the definition of long double precision varies between computers (e.g. Mac vs Windows) slightly different results may occur in the output files.

Test/example files are shipped in the archive with the SUEWS executable, which are based on measurements of the London KCL site, 2011 data (denoted Kc11)

In the following, SS is the site code (e.g. Kc), ss the grid ID, YYYY the year and tt the time interval.





Meteorological input

Input file (60-min)


Meteorological input

Input file (5-min)


Initial conditions

Input - _YYYY.nml(+) file


Property look-up tables

Input text files containing all other input information


Sets model run

Input (located in options main directory)


Summary of model run

Output options


(Optional) 5-min

Output resolution output file


60-min resolution

Output output file


Daily state variables

Output (all years in one file)

(+) There is a second file InitialConditionsSSss_YYYY_EndOfRun.nml or InitialConditionsSSss_YYYY+1.nml in the input directory. At the end of the run, and at the end of each year of the run, these files are written out so that this information could be used to initialize further model runs.

2.4. Run the model for example data#

Before running the model with your own data, check that you get the same results as the test run example files provided. Copy the example output files elsewhere so you can compare the results. When you run the program it will write over the supplied files.

To run the model you can use Command Prompt (in the directory where the programme is located type the model name) or just double click the executable file.

Please see Troubleshooting if you have problems running the model.

2.5. Preparation of data#


If you need help preparing the data you can use some of the UMEP tools.

The information required to run SUEWS for your site consists of:

  • Continuous meteorological forcing data for the entire period to be modelled without gaps.

  • Knowledge of the surface and soil conditions immediately prior to the first model timestep.


    If these initial conditions are unknown, model spin-up can help; i.e. run the model and use the output at the end of the run to infer the conditions at the start of the main run). Spin-up is important for getting appropriate initial conditions for the model. An example of a spin-up can be found in Kokkonen et al. [2018].

  • The location of the site (latitude, longitude, altitude).

  • Information about the characteristics of the surface, including land cover, heights of buildings and trees, radiative characteristics (e.g. albedo, emissivity), drainage characteristics, soil characteristics, snow characteristics, phenological characteristics (e.g. seasonal cycle of LAI).


    For guidance on how to derive parameters related to LAI, albedo, surface conductance and surface roughness, the reader is referred to this link.

  • Information about human behaviour, including energy use and water use (e.g. for irrigation or street cleaning) and snow clearing (if applicable).


    The anthropogenic energy use and water use may be provided as a time series in the meteorological forcing file (by setting EmissionsMethod = 0) if these data are available or modelled based on parameters provided to the model, including population density, hourly and weekly profiles of energy and water use, information about the proportion of properties using irrigation and the type of irrigation (automatic or manual).

It is particularly important to ensure the following input information is appropriate and representative of the site:

  • Fractions of different land cover types and (less so) heights of buildings [Ward et al., 2016]

  • Accurate meteorological forcing data, particularly precipitation and incoming shortwave radiation [Kokkonen et al., 2018]

  • Initial soil moisture conditions [Best and Grimmond, 2014]

  • Anthropogenic heat flux parameters, particularly if there are considerable energy emissions from transport, buildings, metabolism, etc [Ward et al., 2016].

  • External water use (if irrigation or street cleaning occurs)

  • Snow clearing (if running the snow option)

  • Surface conductance parameterisation [Järvi et al., 2011, Ward et al., 2016]

SUEWS can be run either for an individual area or for multiple areas. There is no requirement for the areas to be of any particular shape but here we refer to them as model ‘grids’.

2.5.1. Preparation of site characteristics and model parameters#

The area to be modelled is described by a set of characteristics that are specified in the SUEWS_SiteSelect.txt file. Each row corresponds to one model grid for one year (i.e. running a single grid over three years would require three rows; running two grids over two years would require four rows). Characteristics are often selected by a code for a particular set of conditions. For example, a specific soil type (links to SUEWS_Soil.txt) or characteristics of deciduous trees in a particular region (links to SUEWS_Veg.txt). The intent is to build a library of characteristics for different types of urban areas. The codes are specified by the user, must be integer values and must be unique within the first column of each input file, otherwise the model will return an error.


The first column of SUEWS_SiteSelect.txt the is labelled ‘Grid’ and can contain repeat values for different years. See Input files for details. Note UMEP maybe helpful for components of this. Land cover#

For each grid, the land cover must be classified using the following surface types:


Surface type

File where characteristics are specified


Paved surfaces




Bare soil



Evergreen trees


Deciduous trees










The surface cover fractions (i.e. proportion of the grid taken up by each surface) must be specified in SUEWS_SiteSelect.txt. The surface cover fractions are critical, so make certain that the different surface cover fractions are appropriate for your site.

For some locations, land cover information may be already available (e.g. from various remote sensing resources). If not, websites like Bing Maps and Google Maps allow you to see aerial images of your site and can be used to estimate the relative proportion of each land cover type. If detailed spatial datasets are available, UMEP allows for a direct link to a GIS environment using QGIS. Anthropogenic heat flux (QF)#

You can either model QF within SUEWS or provide it as an input.

  • To model it population density is needed as an input for LUMPS and SUEWS to calculate QF.

  • If you have no information about the population of the site we recommend that you use the LUCY model [Allen et al., 2010, Lindberg et al., 2013] to estimate the anthropogenic heat flux which can then be provided as input SUEWS along with the meteorological forcing data.

Alternatively, you can use the updated version of LUCY called LQF, which is included in UMEP. Other information#

The surface cover fractions and population density can have a major impact on the model output. However, it is important to consider the suitability of all parameters for your site. Using inappropriate parameters may result in the model returning an error or, worse, generating output that is simply not representative of your site. Please read the section on Input files. Recommended or reasonable ranges of values are suggested for some parameters, along with important considerations for how to select appropriate values for your site. Data Entry#

To create the series of input text files describing the characteristics of your site, there are three options:

  1. Data can be entered directly into the input text files. The example (.txt) files provide a template to create your own files which can be edited with 5. A text editor directly.

  2. Use UMEP.

Note that in all txt files:

  • The first two rows are headers: the first row is the column number; the second row is the column name.

  • The names and order of the columns should not be altered from the templates, as these are checked by the model and errors will be returned if particular columns cannot be found.

  • Since v2017a it is no longer necessary for the meteorological forcing data to have two rows with -9 in column 1 as their last two rows.

  • “!” indicates a comment, so any text following “!” on the same line will not be read by the model.

  • If data are unavailable or not required, enter the value -999 in the correct place in the input file.

  • Ensure the units are correct for all input information. See Input files for a description of parameters.

In addition to these text files, the following files are also needed to run the model.

2.5.2. Preparation of the RunControl file#

In the RunControl.nml file the site name (SS) and directories for the model input and output are given. This means before running the model (even the with the example datasets) you must either

  1. open the RunControl.nml file and edit the input and output file paths and the site name (with a 5. A text editor) so that they are correct for your setup, or

  2. create the directories specified in the RunControl.nml file

From the given site identification the model identifies the input files and generates the output files. For example if you specify:

FileOutputPath = “C:\FolderName\SUEWSOutput\”

and use site code SS the model creates an output file:



The path separator differs between Windows (backslash: \) and Linux/Mac (slash, or forward slash: /).

If the file paths are not correct the program will return an error when run and write the error to the Error messages: problems.txt file.

2.5.3. Preparation of the Meteorological forcing data#

The model time-step is specified in RunControl.nml (5 min is highly recommended). If meteorological forcing data are not available at this resolution, SUEWS has the option to downscale (e.g. hourly) data to the time-step required. See details about the SSss_YYYY_data_tt.txt to learn more about choices of data input. Each grid can have its own meteorological forcing file, or a single file can be used for all grids. The forcing data should be representative of the local-scale, i.e. collected (or derived) above the height of the roughness elements (buildings and trees).

2.5.4. Preparation of the InitialConditions file#

Information about the surface state and meteorological conditions just before the start of the run are provided in the Initial Conditions file. At the very start of the run, each grid can have its own Initial Conditions file, or a single file can be used for all grids. For details see Initial Conditions file.

2.6. Run the model for your site#

To run the model you can use Command Prompt (in the directory where the programme is located type the model name) or just double click the executable file.

Please see Troubleshooting if you have problems running the model.

2.7. Analyse the output#

It is a good idea to perform initial checks that the model output looks reasonable.


Things to check

Leaf area index

Does the phenology look appropriate?
  • what does the seasonal cycle of leaf area index (LAI) look like?

  • Are the leaves on the trees at approximately the right time of the year?


Is the timing of diurnal cycles correct for the incoming solar radiation?
  • Although Kdown is a required input, it is also included in the output file. It is a good idea to check that the timing of Kdown in the output file is appropriate, as problems can indicate errors with the timestamp, incorrect time settings or problems with the disaggregation. In particular, make sure the sign of the longitude is specified correctly in SUEWS_SiteSelect.txt.

  • Checking solar angles (zenith and azimuth) can also be a useful check that the timing is correct.


Is the bulk albedo correct?
  • This is critical because a small error has an impact on all the fluxes (energy and hydrology).

  • If you have measurements of outgoing shortwave radiation compare these with the modelled values.

  • How do the values compare to literature values for your area?

2.8. Summary of files#

The table below lists the files required to run SUEWS and the output files produced. SS is the two-letter code (specified in RunControl.nml) representing the site name, ss is the grid identification (integer values between 0 and 2,147,483,647 (largest 4-byte integer)) and YYYY is the year. TT is the resolution of the input/output file and tt is the model time-step.

The last column indicates whether the files are needed/produced once per run (1/run), or once per day (1/day), for each year (1/year) or for each grid (1/grid):

[B] indicates files used with the CBL part of SUEWS (BLUEWS) and therefore are only needed/produced if this option is selected
[E] indicates files associated with ESTM storage heat flux models and therefore are only needed/produced if this option is selected

2.9. Get in contact#

For issues met in using SUEWS, we recommend the following ways to get in contact with the developers and the SUEWS community:

  1. Report issues on our GitHub page.

  2. Ask for help by joining the Email-list for SUEWS.