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The Urban Weather Generator engine for Urban Heat Island modelling

Project description

# Urban Weather Generator

[![Build Status](](

The Urban Weather Generator (uwg) is a Python application for modeling the [urban heat island effect]( Specifically, it morphs rural [EnergyPlus weather (.epw) files]( to reflect average conditions within the urban canyon using a range of properties including:

* Building geometry (including building height, ground coverage, window:wall area, and facade:site area)
* Building use (including program type, HVAC systems, and occupancy/equipment scheduling)
* Cooling system heat rejection to the outdoors (for Summer)
* Indoor heat leakage to the outdoors (for Winter)
* Urban materials (including the thermal mass, albedo and emissivity of roads, walls, and roofs)
* Anthropogenic heat from traffic (including traffic schedules)
* Vegetation coverage (both trees and shrubs)
* Atmospheric heat transfer from urban boundary and canopy layers

The [original Urban Weather Generator]( was developed by Bruno Bueno for [his PhD thesis at MIT]( Since this time, it has been validated 3 times and has been [enhanced by Aiko Nakano]( In 2016, Joseph Yang also [improved the engine and added a range of building templates](

This repository is a Python translation of the original [MATLAB Urban Weather Generator](

# Example
Here is a Python example that shows how to create and run an Urban Weather Generator object. The example script is available [at resources/]( Run it through your command prompt in the main uwg directory with the following: ```python -m resources.uwg_example```

from uwg import uwg

# Define the .epw, .uwg filenames to create an uwg object.
# uwg will look for the .epw file in the uwg/resources/epw folder,
# and the .uwg file in the uwg/resources/parameters folder.
epw_filename = "SGP_Singapore.486980_IWEC.epw" # .epw file name
param_filename = "initialize_singapore.uwg" # .uwg file name

# Initialize the UWG object and run the simulation
uwg_ = uwg(epw_filename, param_filename)

Here is the sample .uwg file used in the simulation above. The .uwg file is a a required input where the local building, urban, and geographic features are defined. These features are then used in the simulation to morph the .epw file. This file is available [at resources/initialize_singapore.uwg](

# =================================================
# =================================================

# Urban characteristics
bldHeight,10, # average building height (m)
bldDensity,0.5, # urban area building plan density (0-1)
verToHor,0.8, # urban area vertical to horizontal ratio
h_mix,1, # fraction of building HVAC waste heat set to the street canyon [as opposed to the roof]
charLength,1000, # dimension of a square that encompasses the whole neighborhood [aka. characteristic length] (m)
albRoad,0.1, # road albedo (0 - 1)
dRoad,0.5, # road pavement thickness (m)
kRoad,1, # road pavement conductivity (W/m K)
cRoad,1600000, # road volumetric heat capacity (J/m^3 K)
sensAnth,20, # non-building sensible heat at street level [aka. heat from cars, pedestrians, street cooking, etc. ] (W/m^2)
latAnth,2, # non-building latent heat (W/m^2) (currently not used)

# Climate Zone (Eg. City) Zone number
# 1A(Miami) 1
# 2A(Houston) 2
# 2B(Phoenix) 3
# 3A(Atlanta) 4
# 3B-CA(Los Angeles) 5
# 3B(Las Vegas) 6
# 3C(San Francisco) 7
# 4A(Baltimore) 8
# 4B(Albuquerque) 9
# 4C(Seattle) 10
# 5A(Chicago) 11
# 5B(Boulder) 12
# 6A(Minneapolis) 13
# 6B(Helena) 14
# 7(Duluth) 15
# 8(Fairbanks) 16


# Vegetation parameters
vegCover,0.2, # Fraction of the urban ground covered in grass/shrubs only (0-1)
treeCoverage,0.1, # Fraction of the urban ground covered in trees (0-1)
vegStart,4, # The month in which vegetation starts to evapotranspire (leaves are out)
vegEnd,10, # The month in which vegetation stops evapotranspiring (leaves fall)
albVeg,0.25, # Vegetation albedo
latGrss,0.4, # Fraction of the heat absorbed by grass that is latent (goes to evaporating water)
latTree,0.6, # Fraction of the heat absorbed by trees that is latent (goes to evaporating water)
rurVegCover,0.9, # Fraction of the rural ground covered by vegetation

# Traffic schedule [1 to 24 hour],
0.2,0.2,0.2,0.2,0.2,0.4,0.7,0.9,0.9,0.6,0.6,0.6,0.6,0.6,0.7,0.8,0.9,0.9,0.8,0.8,0.7,0.3,0.2,0.2, # Weekday
0.2,0.2,0.2,0.2,0.2,0.3,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.6,0.7,0.7,0.7,0.7,0.5,0.4,0.3,0.2,0.2, # Saturday
0.2,0.2,0.2,0.2,0.2,0.3,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.4,0.3,0.3,0.2,0.2, # Sunday

# Fraction of building stock for each DOE Building type (pre-80's build, 80's-present build, new)
# Note that sum(bld) must be equal to 1
0,0,0, # FullServiceRestaurant
0,0,0, # Hospital
0,0,0, # LargeHotel
0,0.4,0, # LargeOffice
0,0,0, # MediumOffice
0,0.6,0, # MidRiseApartment
0,0,0, # OutPatient
0,0,0, # PrimarySchool
0,0,0, # QuickServiceRestaurant
0,0,0, # SecondarySchool
0,0,0, # SmallHotel
0,0,0, # SmallOffice
0,0,0, # Stand-aloneRetail
0,0,0, # StripMall
0,0,0, # SuperMarket
0,0,0, # Warehouse

# =================================================
# =================================================

albRoof,0.5, # roof albedo (0 - 1)
vegRoof,0.1, # Fraction of the roofs covered in grass/shrubs (0-1)
glzR,0.5, # Glazing Ratio. If not provided, all buildings are assumed to have 40% glazing ratio
hvac,0, # HVAC TYPE; 0 = Fully Conditioned (21C-24C); 1 = Mixed Mode Natural Ventilation (19C-29C + windows open >22C); 2 = Unconditioned (windows open >22C)

# =================================================
# =================================================

# Simulation parameters,
Month,1, # starting month (1-12)
Day,1, # starting day (1-31)
nDay,31, # number of days to run simultion
dtSim,300, # simulation time step (s)
dtWeather,3600, # weather time step (s)

autosize,0, # autosize HVAC (1 for yes; 0 for no)
sensOcc,100, # Sensible heat per occupant (W)
LatFOcc,0.3, # Latent heat fraction from occupant (normally 0.3)
RadFOcc,0.2, # Radiant heat fraction from occupant (normally 0.2)
RadFEquip,0.5, # Radiant heat fraction from equipment (normally 0.5)
RadFLight,0.7, # Radiant heat fraction from light (normally 0.7)

#Urban climate parameters
h_ubl1,1000, # ubl height - day (m)
h_ubl2,80, # ubl height - night (m)
h_ref,150, # inversion height (m)
h_temp,2, # temperature height (m)
h_wind,10, # wind height (m)
c_circ,1.2, # circulation coefficient (default = 1.2 per Bruno (2012))
c_exch,1, # exchange coefficient (default = 1; ref Bruno (2014))
maxDay,150, # max day threshold (W/m^2)
maxNight,20, # max night threshold (W/m^2)
windMin,1, # min wind speed (m/s)
h_obs,0.1, # rural average obstacle height (m)

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