ediblecity (version 0.2.2)

UHI: Heat island effect

Description

The indicator calculates the urban heat island (UHI) using the DPRA guidelines of the Dutch government.

Usage

UHI(
  x,
  SVF,
  green_df = NULL,
  Qql = 6.11,
  Cair = 1007,
  Pair = 1.14,
  Tmax = 30.8,
  Tmin = 20,
  windspeed = 2.77,
  return_raster = FALSE,
  verbose = FALSE
)

Value

A 'stars' object with values of UHI. Or a numerical vector or summary statistic for UHI values. See params for more information on how to select each one.

Arguments

x

An 'sf' object with the urban model of your city and a 'land_use' column with categories of urban features.

SVF

A 'stars' object representing sky view factor. It can be computed, e.g. with SAGA's Sky View Factor algorithm and then loaded with stars::read_stars().

green_df

A dataframe of categories that are considered as urban green with two columns. 'land_uses' with the names of 'land_use' in 'x' to be considered as green; a 'pGreen' column with the percentage of green of that function. If NULL, categories and values of 'city_land_uses' dataset are considered.

Qql

A numerical value representing the average solar radiation in W/m2/hour.

Cair

A numerical value representing the air heat capacity in J.

Pair

A numerical value representing the air density in kg/m3.

Tmax

Averaged maximum temperature in ºC.

Tmin

Averaged minimum temperature in ºC.

windspeed

Averaged wind speed in m/s.

return_raster

If TRUE, the raster of UHI values is returned. Otherwise, a summary of raster values is returned.

verbose

If TRUE, returns a vector with UHI value in each cell.

Author

Josep Pueyo-Ros

Details

DEFAULT values are the values for 'city_example' dataset in August (averaged values from 2011-2020)

Examples

# Get a summary of the UHI
UHI(city_example, SVF)

# Get a 'stars' object representing UHI
uhi <- UHI(city_example, SVF, return_raster = TRUE)
plot(uhi)