User manual
Usage of the tool is simple. In order to assess the heat stress in the AST and to see the effect of interventions the user has to:
- Select or draw and define several interventions
- Click on the button ‘bereken hittestress’ (WAT STAAT ER PRECIES? WELKE TAAL?
- Click either the buttons
- PET for situation before interventions,
- PET-reduction
- PET for situation before interventions,
To provide an indication of the Urban heat Stress in the public urban space, the AST presents the comfort temperature as PET (Physiological Equivalent temperature) index values in °C. In addition to this, AST presents the effect of interventions on reducing the PET.
PET is only one of many possible indicators for urban heat stress. In the Netherlands the PET has been chosen as one of the main indicators for urban heat stress and a standardized way [JK1] [LvZ2] [LvZ3] [LvZ4] [JK5] to to calculate this PET has been chosen and has been described by (Koopman et al., 2020). For all Dutch urban areas PET values, for a hot summer day, are freely available at www.klimaateffectlas.nl. The PET values presented are the average PET values from 12:00 until 17:59 for this summer day.
The PET values give an indication of the heat stress people would be exposed to at each m2 of the urban area as presented in following table 1, which combines different levels of heat stress to PET values. The publication (Spanjar et al, 2020), [JK6] provides the following short introduction to explain PET:
| People experience heat stress when too much heat is absorbed by the body (Epstein & Moran, 2006). It can cause a decrease in mental and manual performance, have negative effects on social behaviour, cause heat exhaustion and heat stroke, and may even lead to death (Bell, 1981; Epstein & Moran, 2006; Pilcher et al., 2002). In humans it can be measured by the Physiological Equivalent Temperature (PET) index and this is the most commonly used climate comfort index when measuring outdoors (Coccolo et al., 2016; Matzarakis et al., 2014). The PET-index is expressed in degrees Celsius (°C). |
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PET (°C) Physiological Stress Grade
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AST uses the calculations steps below to asses the PET values in a raster of 1*1[LvZ9] [JK10] m2*2m2 in the project area. Roofs and water are excluded from the calculations, as people are not expected to be there. To provide a logical outcome while keeping the required calculations simple, AST calculates for each raster pixel the differences between the local PET value and a local minimal PET value (in an area of 2km2). For the raster pixels at which an intervention is planned, this PET difference is multiplied with the expected reduction factor (see table). This gives the expected PET reduction in °C. This methodology was chosen in order to calculate in a simple way the effect of interventions which would overlay earlier heat reducing features or cooler situations (like shadow of existing trees/buildings and existing green), without presenting a double effect of the old and new interventions.
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- Assessment of the minimum PET value in the 2km2 surrounding the project area (including the project area). è PET_minumum
- For each rasterpoint raster point with an intervention define the maximum reduction factor of the PET: RF_PET. If interventions overlap only the maximum RF is applied.
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The results for overlapping and non-overlapping interventions and for interventions overlapping current head reducing features appear logical. In some situations, old heat reducing features (like the shadow of building) might be slightly visible in color differences, but they result only in small differences (up to several degrees) as compared to the 6 °C PET-difference between two classes of heat stress. Users should understand the simplicity of the model and the fact that only rough estimations of heat stress reduction can be given as the effect of the interventions on the PET is also dependent on many local characteristics and situation of the people who should feel the difference in comfort temperature. Such local information is not available nor part of the PET map which is used as input for the PET in the AST.
User manual
The user manual is simple. In order to assess the heat stress in the AST and to see the effect of interventions the user has to:
- Select or draw and define several interventions
- Click on the button ‘bereken hittestress’ (WAT STAAT ER PRECIES? WELKE TAAL?
- Click either the buttons
- PET for situation before interventions,
- PET-reduction
- PET for situation before interventions,
[JK1]Link to rapport van rivm.
[LvZ2]https://www.sciencedirect.com/science/article/pii/S0360132320303644
[LvZ3]https://edepot.wur.nl/528690
[LvZ4]Dit zijn links naar Engelse (wetenschappelijke) bronnen voor hetzelfde verhaal.
[JK5]Dank luuk, link heb ik toegevoegd
[JK6]Cool towns heat stress protocol ,(Spanjar et al, 2020)
Nu link naar project dir, Link naar document later toevoegen (Luc)
[JK7]Dit in een kader en met verwijzing naar Protocol
Ok! De definitieve link naar het protocol hebben we nog niet. [LvZ8]
[LvZ9]2x2 toch?
[JK10]Reinder???