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== Ingredients ==
The [[DPRA Heat Module]] for the [[Heat Overlay]] can be used for heat stress calculations, based on geographical features and locale parameters. The final result is the [[Pet result type (Heat Overlay)|physiological equivalent temperature]], which is a measure of temperature which takes into account factors which can change the experience and effects of temperature.
 
The module performs these calculations in accordance with the {{Heat DPRA Report}}.
 
[[File:Overview_Heat_Module.jpg|500px]]
==Input factors==
The calculation of the Heat Stress Overlays takes into account:
The calculation of the Heat Stress Overlays takes into account:
* Meteorological circumstances such as:
* Meteorological circumstances such as:
** Sun angles, [[altitude]] and [[azimuth]], dependent on date and time of day and project location.
** Sun angles, [[Sun_altitude_(Heat_Overlay)|altitude]] and [[Sun_azimuth_(Heat_Overlay)|azimuth]], dependent on date and time of day and project location.
** air temperatures, ([[hourly]], [[daily minimum]] and [[maximum]]);
** Air temperatures, ([[Hourly_temperature_(Heat_Overlay)|hourly]], [[Daily_temperature_min_(Heat_Overlay)|daily minimum]] and [[Daily_temperature_max_(Heat_Overlay)|maximum]]);
** global radiation
** Global radiation, ([[Hourly_radiation_(Heat_Overlay)|hourly]] and [[Daily_avg_radiation_(Heat_Overlay)|average]]);
** relative humidity
** Relative humidity ([[Hourly_humidity_(Heat_Overlay)|hourly]]);
** wind speeds, measured and [[calculated by translation]].
** Wind speeds ([[Wind_speed_(Heat_Overlay)|hourly]] and [[Daily_avg_wind_speed_(Heat_Overlay)|daily average]]).
** Wind direction ([[Wind_direction_(Heat_Overlay)|hourly]])
* Spatial situation, such as:
* Spatial situation, such as:
** Land use, for fraction vegetation and rate of evaporation ([[Bowen ratio]]).
** Land use, for fraction vegetation and rate of evaporation ([[Bowen_ratio_(Heat_Overlay)|Bowen ratio]]).
** Terrain, foliage and building heights
** Terrain, [[Foliage_crown_factor_(Heat_Overlay)|foliage]] and building heights
 
==Calculation of Physiological Equivalent Temperature==
To calculate the Physiological Equivalent Temperature (PET), we first have to determine which formula (''sun'' or ''shade/night'') should be used.
It is selected by:
* Day or night? Determined by the [[Sun_altitude_(Heat_Overlay)|sun altitude angle]];
* Is a cell shaded? Calculated by the [[Shade_calculation_model_(Heat_Overlay)|shade calculation model]];
 
===PET sun===
The following factors influence the [[PET_formulas_(Heat_Overlay)|Physiological Equivalent Temperature]] for locations directly in the sun:
* The [[Temperature_atmosphere_result_type_(Heat_Overlay)|atmospheric temperature]], calculated by the [[Temperature_formulas_(Heat_Overlay)#Atmospheric Temperature formula|atmospheric temperature formula]];
* The [[Hourly_radiation_(Heat_Overlay)|hourly global radiation]] from the sun, supplied as weather station data;
* The [[Wind_speed_result_type_(Heat_Overlay)|wind speed]] at 1.2 meter above ground, calculate by the [[Wind_calculation_model_(Heat_Overlay)|wind speed calculation model]];
* The Wet-Bulb temperature, calculated by the [[Temperature_formulas_(Heat_Overlay)#Wet-bulb_Temperature_formula|Wet Bulb temperature formula]];
* The [[Sun_altitude_(Heat_Overlay)|sun altitude]], calculated automatically based on the project area, date and time of day;
* The [[Bowen_ratio_(Heat_Overlay)|Bowen ratio]], an attribute obtained from Buildings or Terrain on that specific location;
* The [[Sky_view_result_type_(Heat_Overlay)|sky view factor]], calculated by the [[Sky_view_factor_calculation_model_(Heat_Overlay)|sky view factor calculation model]].
 
===PET shade and night===
The following factors influence the [[PET_formulas_(Heat_Overlay)|Physiological Equivalent Temperature]] for locations directly in the shade or at night:
* The [[Temperature_atmosphere_result_type_(Heat_Overlay)|atmospheric temperature]], calculated by the [[Temperature_formulas_(Heat_Overlay)#Atmospheric Temperature formula|atmospheric temperature formula]];
* The [[Wind_speed_result_type_(Heat_Overlay)|wind speed]] at 1.2 meter above ground, calculate by the [[wind_calculation_model_(Heat_Overlay)|Wind speed calculation model]];
* The Wet-Bulb temperature, calculated by the [[Temperature_formulas_(Heat_Overlay)#Wet-bulb_Temperature_formula|Wet Bulb temperature formula]];
* The [[Sky_view_result_type_(Heat_Overlay)|sky view factor]], calculated by the [[Sky_view_factor_calculation_model_(Heat_Overlay)|sky view factor calculation model]].
* The diffuse radiation, calculated by the [[Diffuse_radiation_formula_(Heat_Overlay)|diffuse radiation formula]].
 
==Required information==
In order to configure the [[Heat Overlay]] accurately additional data needs to be loaded in:
* [[Dates (Heat Overlay)|Date(s) and time of day]]. Also multiple consecutive days can be used. Each day-hour combination will become a result.
* Daily [[Weather station (Heat Overlay)|weather station]] data
* Hourly weather station data
* [[Foliage height calculation model (Heat Overlay)|Foliage height]]s (although a [[foliage crown factor (Heat Overlay)|means of estimation]] is available)


== Setup ==
==See also==
Generally, the steps required to use the Heat Stress Overlay are as followed:
* [[Getting started (Heat Overlay)]]
# Determine the location and area of interest and generate a project for that area.
* [[Heat Overlay Wizard (Heat Overlay)]]
# Add the Heat stress overlay
* [[Calculation models and formulas (Heat Overlay)]]
# Configure for which date you want to generate results for. This can be one day or multiple consecutive days when using the Heat Overlay Wizard.
 
<!--
==Getting started with the Heat Module==
In order to get acquainted with configuring the Heat Overlay, follow our [[Tutorial_Heat_Overlay_(Heat_Overlay) |Heat Overlay Tutorial]] and/or the instructions on our . The process of configuring the Heat Overlay can be guided by the [[|Heat Overlay configuration wizard]].
 
====Date and time of day====
# Select a day for which you want to generate results. You can also choose to select multiple consecutive days when using the Heat Overlay Wizard.
# Configure per day which hours you want to generate results for. Each day-hour combination will become a result. This result is stored as a time-frame to relate it back to the day and time.
# Configure per day which hours you want to generate results for. Each day-hour combination will become a result. This result is stored as a time-frame to relate it back to the day and time.


===Generated sun parameters===
====Generated sun parameters====
For each day, and for each time of day, the following will be automatically generated when using the wizard:
For each day, and for each time of day, the following will be automatically generated when using the wizard:
# The day and time pairs, along with the project location, will be used to automatically calculate the sun altitude and azimuth angles for each day-time pair.  
# The day and time pairs, along with the project location, will be used to automatically calculate the sun altitude and azimuth angles for each day-time pair.  
# The sun daily motion factor is a parameter used in the atmospheric temperature formula. It will be automatically selected from the sun motion factor table, based on the date (column) and time of day (row).
# The [[Sun_daily_motion_(Heat_Overlay)|sun daily motion factor]] is a parameter used in the atmospheric temperature formula. It will be automatically selected from the sun motion factor table, based on the date (column) and time of day (row).


====Daily Values====
====Weather station data====
Next, manually determine which weather station you want to use as a reference. Download the historical hourly weather data for that station and use certain columns as input.
Next, manually determine which weather station you want to use as a reference. Download the historical hourly weather data for that station and use the data from certain columns as input.
In a nutshell, using the weather data, you have to supply:
In a nutshell, using the weather data, you have to supply:
# the minimum and maximum temperature of the day;
 
# the average wind speed, measured at the height of 10 meters;
*'''Daily Values'''
# global sun radiation during sun hours;
# The [[Daily_temperature_min_(Heat_Overlay)|minimum]] and [[Daily_temperature_max_(Heat_Overlay)|maximum temperature]] of the day;
====Hourly Values====
# The [[Daily_avg_wind_speed_(Heat_Overlay)|average wind speed]], measured at the height of 10 meters;
For each time of day, for each day selected:
# The [[Daily_avg_radiation_(Heat_Overlay)|average global sun radiation]] during sun hours;
# The hourly temperature and humidity;
*'''Hourly Values'''
# The hourly sun radiation, as an average of the current and previous hour;
# The [[Hourly_temperature_(Heat_Overlay)|hourly temperature]];
# The hourly wind speed;
# The [[Hourly_humidity_(Heat_Overlay)|hourly humidity]];
# The [[Hourly_radiation_(Heat_Overlay)|hourly sun radiation]], as an average of the current and previous hour;
# The [[Wind_speed_(Heat_Overlay)|hourly wind speed]];
# The [[Wind_direction_(Heat_Overlay)|hourly wind direction]];


====Foliage Height====
====Foliage Height====
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* Buildings with [[Function|functions]] related to foliage. The [[Foliage_height_calculation_model_(Heat_Overlay)|foliage height calculation model]] will determine the foliage height using the height of the vegetation (as buildings) and the foliage crown factor attribute;
* Buildings with [[Function|functions]] related to foliage. The [[Foliage_height_calculation_model_(Heat_Overlay)|foliage height calculation model]] will determine the foliage height using the height of the vegetation (as buildings) and the foliage crown factor attribute;
* Areas with as foliage height attribute, defining the foliage height for a whole area;
* Areas with as foliage height attribute, defining the foliage height for a whole area;
* [[GeoTiff]], defining a foliage height value for each cell in its raster.
* [[GeoTIFF]], defining a foliage height value for each cell in its raster.
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{{HeatOverlay model attribute nav}}

Latest revision as of 09:28, 2 March 2023

The DPRA Heat Module for the Heat Overlay can be used for heat stress calculations, based on geographical features and locale parameters. The final result is the physiological equivalent temperature, which is a measure of temperature which takes into account factors which can change the experience and effects of temperature.

The module performs these calculations in accordance with the DPRA Heat stress report.

Overview Heat Module.jpg

Input factors

The calculation of the Heat Stress Overlays takes into account:

Calculation of Physiological Equivalent Temperature

To calculate the Physiological Equivalent Temperature (PET), we first have to determine which formula (sun or shade/night) should be used. It is selected by:

PET sun

The following factors influence the Physiological Equivalent Temperature for locations directly in the sun:

PET shade and night

The following factors influence the Physiological Equivalent Temperature for locations directly in the shade or at night:

Required information

In order to configure the Heat Overlay accurately additional data needs to be loaded in:

See also