Urban cooling, Cooling capacity calculation method

[Olivier]

Hello NatCap team,

I’m starting to use the UC model (InVEST V3.11.0). I was able to test the model and it’s working fine. My LULC layer is 10m*10m and the building footprints are well defined (which helps to assess building intensity).
However I’ve a question related to the “cooling capacity calculation method” parameter.
The model allows to decide to use “weigheted factors” (my run 1) or “building intensity” (my run 2).
I’ve tried both and the results are quit different visually (on QGIS) and quantitatively:
For run 1 my “avg_cc” average is 0.48.
For run 2 my “avg_cc” average is 0.93.

So here is my question : Is there a way to decide which calculation method to choose? In other words, which one is the most accurate calculation method?

You can see below illustrations of the results (run 1 and 2 have the same symbology to be able to compare the results).

Google Earth photo:

Heat (red) to cool (blue) island layer created by Québec ministry team. This layer helped me to check that my biophysical table were well done:

Run 1 (weighted factor):

Run 2 (building intensity):

Thanks in advance for your answer and thanks for the great models you create!

Olivier

[jesseG]

Hi @Olivier ,

Thanks for your question and for using InVEST!

This likely should be described more clearly in the UI. If you give the User Guide a careful read, you may be able to glean that in fact the “weighted factors” method is intended for modeling daytime impacts (as it uses ET, shade, and albedo) whereas the “building intensity” method is meant for modeling night time conditions (based upon stored heat released by built infrastructure that’s warmer than the ambient air). This would explain the differences in your results. Most UC studies are concerned with daytime primarily, so I’d guess that’s what you want to use, at least initially.

Please let us know if you have more questions.

-Jesse