Trouble understanding Urban Weather Generator inputs and calculation of wind speed for modeling air source heat pump

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Dear energy modeling community,

I wanted to kindly reach out here to ask for some technical guidance with my implementation of the Urban Weather Generator (UWG) tool, which I see is now managed by Ladybug Tools. My apologies if the topic of urban microclimate analysis through a specific external tool like the UWG is outside the scope of this forum, but I felt that because my use of UWG here is more a question of how heating and cooling loads in EnergyPlus are specifically influenced by variations in outdoor conditions through the urban heat island effect, that my question would still be relevant and of interest here.

The problem is that while the UWG runs, I find that the tool is not picking up variation in windspeed, along with some other key weather file outputs.

Because I struggle with grasping the Grasshopper environment, I chose to implement the Urban Weather Generator tool using the pure python script from this GitHub repository, which I see is managed by Ladybug Tools:

https://github.com/ladybug-tools/uwg

To demonstrate the issue I am encountering with the UWG tool, I tried to take a base case reference TMY3 EPW file for New York City – Central Park and use UWG to modify the ‘bldheight’, ‘blddensity’, ‘vertohor’, ‘grasscover’, and ‘treecover’ parameters. I tried to modify these parameters in two “extreme” test cases where I create a heavily developed test case to be compared with a much less developed test case, to compare how the output microclimate-adjusted EPW would be influenced, with the expectation that I would see significant variation in my weather file outputs of interest: outdoor drybulb temperature, outdoor relative humidity, and windspeed.

Here is how I am implementing the code, first starting with my “very green microclimate” (Test 1):

from uwg import UWG

# Define the .epw, .uwg paths to create an uwg object.
epw_path = r"C:/Users/MyName/Downloads/USA_NY_New.York-Central.Park.725033_TMY3.epw"

new_epw_name = r"C:/Users/MyName/Downloads/USA_NY_New.York-Central.Park.725033_TMY3_test1.epw"

# Initialize the UWG model by passing parameters as arguments, or relying on defaults
model = UWG.from_param_args(epw_path=epw_path, new_epw_name=new_epw_name, bldheight=3, blddensity=0.05,
                            vertohor=0.08, grasscover=0.65, treecover=0.30, zone='4A')

model.generate()
model.simulate()

# Write the simulation result to a file.
model.write_epw()

I then create the microclimate-adjusted EPW file for my “extremely developed microclimate” (Test 2):

new_epw_name = r"C:/Users/MyName/Downloads/USA_NY_New.York-Central.Park.725033_TMY3_test2.epw"

# Initialize the UWG model by passing parameters as arguments, or relying on defaults
model = UWG.from_param_args(epw_path=epw_path, new_epw_name=new_epw_name, bldheight=50, blddensity=0.91,
                            vertohor=3.5, grasscover=0.05, treecover=0.03, zone='4A')

model.generate()
model.simulate()

# Write the simulation result to a file.
model.write_epw()

The code runs, but when I open the output microclimate-adjusted weather files (.epw) and plot the time series data, I see that while the UWG tool noticeably captured variation in outdoor temperature and relative humidity, there is no variation at all in windspeed between both test ... (more)