WindChill

Resumen

Identifies dangerous winter conditions that, depending on exposure times to the elements, can result in frostbite or hypothermia.

Debate

The formula the function uses to compute wind chill is as follows:

Wind Chill = 35.74 + (0.6215 * T) - (35.75 * WS^0.16) + (0.4275 * T * WS^0.16)

• T = Air Temperature in degrees Fahrenheit
• WS = Wind speed in miles per hour

For more information about how this function works, see the Wind Chill raster function.

The referenced raster dataset for the raster object is temporary. To make it permanent, you can call the raster object's save method.

Sintaxis

WindChill (temperature_raster, wind_speed_raster, {temperature_units}, {wind_speed_units}, {wind_chill_units})

Parámetro	Explicación	Tipo de datos
temperature_raster [temperature_raster,...]	Un ráster de una única banda en el que los valores de píxeles representan la temperatura ambiente del aire.	Raster
wind_speed_raster [wind_speed_raster,...]	A single-band raster where pixel values represent wind speed.	Raster
temperature_units	La unidad de medida asociada al ráster de temperatura de entrada. Las unidades de entrada disponibles son Celsius, Fahrenheit y Kelvin. (El valor predeterminado es Fahrenheit)	String
wind_speed_units	Defines the unit of measurement for the wind-speed raster: mph—Miles per hour km/h—Kilometers per hour m/s—Meters per second ft/s—Feet per second kn—Knots (El valor predeterminado es mph)	String
wind_chill_units	La unidad de medida asociada al ráster de salida. Las unidades de salida disponibles son Celsius, Fahrenheit y Kelvin. (El valor predeterminado es Fahrenheit)	String

Valor de retorno

Tipo de datos	Explicación
Raster	The output raster.

Muestra de código

WindChill example 1

Calculates wind chill based on the temperature and wind speed from the input raster.

from arcpy.sa import *
out_windchill_raster = WindChill("temperature.tif", "windspeed.tif", "",
                                 "km/h", "Celsius")
out_windchill_raster.save("C:/arcpyExamples/outputs/wind_chill_C.tif")

WindChill example 2

Calculates wind chill based on the temperature and wind speed from the input raster.

# Import system modules
import arcpy
from arcpy.sa import *

# Set the analysis environments
arcpy.env.workspace = "C:/arcpyExamples/data"

# Set the local variables
in_temperature_raster = "temperature.tif"
in_wind_speed_raster  = "windspeed.tif"

# Execute WindChill function
out_windchill_raster = WindChill(in_temperature_raster, in_wind_speed_raster,
                                 "", "knots", "Kelvin")
# Save the output
out_windchill_raster.save("C:/arcpyExamples/outputs/wind_chill_K.tif")