In my doctoral thesis, I’m using the urban cooling model and have chosen to explore the limits of the land use I’m incorporating in terms of its cooling capacity. The concept is to conduct simulations of the same land use under various Tair (air temperature) and UHI (Urban Heat Island) effect conditions. Strangely, the results remain consistent beyond 28 degrees Celsius, regardless of how elevated I set the air temperature and UHI effect. I’m puzzled by this, and I’m wondering if anyone can provide an explanation? I attached screenshots of the graph of the average cooling capacity under different conditions.
Hi @EAM07 , great question. In this model the Cooling Capacity is not a function of baseline air temperature or UHI, rather it is a function of the landcover and evapotranspiration, and optionally, building intensity. I’m referring to equation 106 in the User’s Guide to reach this conclusion. Urban Cooling Model — InVEST® documentation
In reality evapotranspiration is surely a function of air temperature, but since the model is simple, it treats these two inputs as independent. Perhaps you might wish to try scenarios where evapotranspiration varies as well?
I have a another question regarding the urban cooling model. In this same study, I try to remove the forest that is next to one part of the industrial park I’m working so I can investigate the impact of the surroundings, but according to the model, whether there’s a forest or a bare land next to the industrial park, has no impact on the industrial park itself. Can you explain this? And is it normal to have the same temperature values, with or without a forest nearby?
I think it all comes down to the parameter values you have assigned to the different landcover classes, forest vs. bare land. Differences in those parameters should be reflected in the results. Often it’s useful to explore some of the intermediate results, such as the cooling capacity, heat mitigation index, or others, to understand where the changes are or aren’t manifesting.
I played around with the parameters to see if in the shapefile, the impact of the forest will appear. However, the cooling capacity of the parcels that are near the forest does not change. I find it weird that the values of the cooling capacity of these parcels are different than the values in the intermediate file. Is this normal?
I attached the file so you can see what I’m talking about, the dark cresent on the the right is an industrial park, and on the left side of it, there’s a forest in the north and a city in the south. The cooling capacity inside the industrial park is the same everywhere, although I would speculate higher values in the northern part because of its proximity to the forest. This is clear in the CC intermediate file, but in the shapefile the value is almost the same everywhere. There is also a river on the right side of the industrial park, I was wondering if this is maybe cancelling out the impact of the forest? Any thoughts? Thanks again
@EAM07 , The shapefile output is a summary of the values in the raster layers. For example, the column in the shapefile called “avg_cc” is the average of all the cooling capacity pixels in that polygon/parcel. Vector format data, like a shapefile, cannot show variation within a single polygon. It is only good for comparing one polygon to another. Instead, the raster data shows the continuous variation across the landscape, as you noted.
