Hi @tng44,
I apologize if I do not fully understand your question.
To calculate HMi, the model amends CCi to account for the fact that large green spaces have a disproportionately large cooling effect on surrounding areas.
HMi is either:
- equal to CCi if the pixel (i) is unaffected by a large green space OR
- set to a distance-weighted average of CCi and a large green space if one is close enough to have an impact.
Zardo et. al. (https://doi.org/10.1016/j.ecoser.2017.06.016) did not consider the effect of albedo in their study. They did find that in areas >2 hectares (ha), ET had a greater effect relative to shading and albedo than it did in areas <2 ha. InVEST’s equations are intended to differentiate CC from HM. Both are affected by all three factors. Perhaps @chris could provide more insight as to the model’s construction.
If you have data or insights from your city of interest, you are welcome to use them to aid you in manually adjusting CC index weights, but we caution against changing them dramatically from the defaults without intimate knowledge of your particular city. My understanding is that this model has been tested more extensively in temperate climates and its parameters may need to be tweaked for use in tropical cities.
I hope this information is helpful to you.
-Jesse