Urban Energy Balance - SUEWS Advanced
The tutorial Urban Energy Balance - SUEWS Introduction should be completed first. This tutorial is designed to work with QGIS 3.x.
To explore the link between QGIS and SUEWS to include new site-specific information
To examine how it affects the energy fluxes
Overview of steps
Initially become familiar with SUEWS advanced which is a plugin that makes it possible for you to set all parameters that can be manipulated in SUEWS as well as execute the model on multiple grids (Urban Energy Balance - SUEWS Spatial).
Derive new surface information
Run the model
How to run SUEWS Advanced from the UMEP-plugin
Open the plugin which is located at UMEP -> Processor -> Urban Energy Balance -> Urban Energy Balance (SUEWS/BLUEWS, Advanced). This has most of the general settings (e.g. activate the snow module etc.) which are related to RunControl.nml.
Use the Input folder: C:/Users/your_user_name/AppData/Roaming/QGIS/QGIS3/ profiles/default/python/plugins/UMEP/suewsmodel/Input/. The AppData folder might be hidden on your system. Then you need change the settings in your File explorer to also show hidden files and folders. On an iOS system this folder is located at: /Library/Applications/QGIS/QGIS3/profiles/default/ python/plugins/UMEP/suewsmodel/Input/
Create or enter an Output directory of your choice.
From the Input folder - confirm the data are in there.
Tick in Obtain temporal… and set Temporal resolution of output (minutes) to 60.
Make sure that output files are created.
You can now close the SUEWS/BLUEWS (Advanced)-plugin again.
The default dataset included in Suews Simple has parameters calculated from a source area model to obtain the appropriate values for the input parameters. Roughness parameters such as roughness length (z0) and zero plane displacement length (zd) are calculated using morphometric models. Now you will explore the differences in fluxes using the default settings or using input parameters from the geodata included in the test datasets available for this tutorial. Download the zip-file (see below) and extract the files to a suitable location where you have both reading and writing capabilities.
Data for the tutorial can be downloaded here.
Ground and building DSM
DSM_LondonCity_1m.tif (m asl)
CDSM_LondonCity_1m.tif (m agl)
DEM (digital elevation model)
DEM_LondonCity_1m.tif (m asl)
They are all projected in UTM 31N (EPSG:32631). The three surface models originate from a LiDAR dataset. The land cover data is a mixture of Ordnance Survey and the LiDAR data.
Open the geodatasets. Go to Layer > Add layer > Add Raster Layer. Locate the files you downloaded before (see above). You can also drag and drop the data from the Browser-panel to the Layer-panel in QGIS.
A QGIS style file (landcoverstyle.qml) is available for the land cover grid. It can found in C:/Users/your_user_name/AppData/Roaming/QGIS/QGIS3/profiles/ default/python/plugins/UMEP/LandCoverReclassifier. Load it in the Layer > Properties > Symbology > Style (lower left) Load Style.
Click Apply before you close so that the names of the classes also load. You can also get the properties of a layer by right-clicking on a layer in the Layers-window.
If you have another land cover dataset you can use the LandCoverReclassifier in the UMEP pre-processor to populate with the correct values suitable for the UMEP plugin environment.
Now take a moment and investigate the different geodatasets. What is the spatial (pixel) resolution? How is ground represented (what values) in the CDSM?
Generating data from the geodatasets
Make certain that you have the four geodatafiles open. The file at the top of the layers window is the one that is shown on the canvas (figure below). You can swap their order using the layers window.
Open SUEWS Simple.
Begin by adding the test dataset again.
You will now update the building morphology parameters (top left panel in Suews Simple) by generating new values from the geodata. Click Open tool…
This is another plugin within UMEP that can be used to generate morphometric parameters
First, clear the map canvas from your two other plugin windows, e.g. as figure above.
If you use the default test data in SUEWS Simple - you can overwrite is as you go.
Locate the eddy covariance tower position on the Strand building, King’s College London. To find the position, consult Figure 1 (KSS) in Kotthaus and Grimmond (2014).
Use Select point on canvas and put a point at that location.
Generate a study area. Use 500 m search distance, 5 degree interval and click Generate study area. A circular area will be considered.
Enter the DSM and DEM files (i.e. the files you currently have in the viewer).
Use Kanda et al. (2013) as Roughness calculation method and build as File prefix.
In the folder you specified two additional files will be present (i) isotropic - averages of the morphometric parameters (ii) anisotropic - values for each wind sector you specified (5 degrees).
Close this plugin
Click on Fetch file from… in the building morphology panel.
Choose the isotropic file (just generated).
Do the same for vegetation (upper left panel, right). See figure below.
Instead of locating the point again you can use the existing point.
You still need to generate a separate study area for the vegetation calculation.
Examine the CDSM (vegetation file) in your map canvas. As you can see, this data has no ground heights (ground = 0). Therefore, this time Tick the box Raster DSM (only buildings) exist.
Enter the CDSM as your Raster DSM (only 3D objects).
If you see a warning that appears that your vegetation fractions between the morphology dataset and land cover dataset are large, you can ignore this for now since the land cover dataset also will change.
Repeat the same procedure for land cover as you did for buildings and vegetation but instead using the Land Cover Fraction (Point) plugin. Use lc as the File prefix
Enter the meteorological file (For Windows users: C:/Users/your_user_name/AppData/Roaming/QGIS/QGIS3/ profiles/default/python/plugins/UMEP/suewsmodel/Input/Kc_2011_data_60.txt), Year etc. This should be the same as the first run you made.
Now you are ready to run the model. Click Run.
Save your plots. Preferable you can zoom in on a couple of days for easier analysis later on.
You are now familiar with the full capabilities of the Suews Simple plugin. Your next task is to choose another location within the geodataset domain, generate data and run the model. Try to choose an area where the fraction of buildings and paved surfaces are low. Consider lowering the Population density to get more realistic model outputs. Compare the results for the different areas. When you are done, compare the fluxes beteen the two runs and try to identify and find explanations for the differences.
Grimmond CSB and Oke 1999: Aerodynamic properties of urban areas derived, from analysis of surface form. Journal of Applied Climatology 38:9, 1262-1292
Grimmond et al. 2015: Climate Science for Service Partnership: China, Shanghai Meteorological Servce, Shanghai, China, August 2015.
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Ward HC, L Järvi, S Onomura, F Lindberg, A Gabey, CSB Grimmond 2016 SUEWS Manual V2016a, http://urban-climate.net/umep/SUEWS Department of Meteorology, University of Reading, Reading, UK
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Ward HC, S Kotthaus, CSB Grimmond, A Bjorkegren, M Wilkinson, WTJ Morrison, JG Evans, JIL Morison, M Iamarino 2015b: Effects of urban density on carbon dioxide exchanges: observations of dense urban, suburban and woodland areas of southern England. Env Pollution 198, 186-200