OTC

Approach

Most methodologies pertaining to thermal comfort studies involve the use/mapping of outdoor thermal comfort (OTC) indices at multiple spatial scales. These OTC indices can be based on empirical relationships observed between a combination of meteorological variables (air temperature, air humidity, and wind speed,…) and individual sensations of thermal comfort surveyed in controlled indoor or static settings (i.e. fixed wind speed and humidity in-situ). It can alternately be computed from the resolution of a complex set of physical equations representing the human body’s thermoregulation processes with its surroundings. A challenge, however, is that these indices – and derivation of thresholds related to thermal comfort and discomfort – often do not account for dynamic variations of OTC resulting from human agency. In this study, we thus propose to examine spatiotemporal patterns of Singapore pedestrians relative to prevailing microscale weather conditions in their everyday commute activities. We posit that variations in OTC sensation can be inferred through changes in walking patterns vis-à-vis prevailing weather patterns. For this purpose, we select two focus urban districts characterized by different social activities (residential versus mixed activities) and population (young active versus family). In each district, randomly selected pedestrians are (i.) tracked with the help of telecom GPS technologies, and (ii.) asked to answer to a series of survey questions related to their decision of walking at the time of the survey, route choices (e.g. between vegetated and naturally shaded routes versus artificially shaded routes), and preferred behavioural adaptation option under different weather conditions.

Findings

Some of the results for Singapore are:

  • Current meteorological stations in Singapore are inadequate for representing the microclimate (prevailing micro weather patterns). The network of meteorological stations does not necessarily represent the local climate zones (i.e. a typology of land use patterns with respect to their impacts on local atmospheric energy and dynamic processes). The meteorological stations are also located at too many different vertical heights to be directly exploitable. A complex downscaling and homogenisation of such observations have to be done in an urban area.
  • Although it has a great potential to assess the exposure of people to a given risk, non obtrusive GPS tracking experiments are still restricted in Singapore by law.
  • OTC surveys’ usual devices like the Kestrel 5400, cannot be used alone to measure the air and humidity temperature as well as the wind speed when conducting mobile atmospheric observations. The hysteresis of such an instrument can be up to 6 minutes. A network of meteorological sensors with different accuracy and time responses have to be built to appropriately measure the meteorological variables.

Outputs

  • A new type of OTC threshold for commuting people in the two districts studied.
  • A hierarchy of the behavioral adaptation strategy adopted by Singaporeans to thermal discomfort.
  • Better understanding on the linkage between walking activity and weather conditions in Singapore.

Links to other tasks

By providing insight on the thermal acceptability of the Singaporean population in different contexts (spaces and activity, here commutings) this research is directly linked with the assessment of OTC strategies at a local scale (project Juan, Lea, Gloria, Elliot).

Summary

This research project aims to increase knowledge on how the Singaporean population adapts to and accepts their thermal environment in their everyday life. This research will also contribute as a first move toward the construction of a non steady-state OTC index suitable for the Tropics.

 Fig 1. Outdoor Thermal Comfort related campaign in Singapore / Source: Lina Meisen Photography

Fig 1. Outdoor Thermal Comfort related campaign in Singapore / Source: Lina Meisen Photography

Population Survey

Approach

The Population Survey objectives are:

  1. Understand people’s environmental attitudes and beliefs about spending time outdoors (day or night).
  2. Understand people’s beliefs and awareness of urban warming.
  3. Evaluate people’s preferences for different mitigation strategies.
  4. Measure willingness to pay (WTP) for mitigation strategies.

To do so, we are implementing a monetary incentivised and anonymised online questionnaire for Singapore with a representative sample of 2000 respondents. We are using experimental methods typical of behavioural psychology and economics. The survey has three parts and in each of them, we want to evaluate: 1. Environmental attitudes, beliefs and level of awareness; 2. Preferences for different mitigation strategies and; 3. Economic valuation by the implementation of a Contingent Valuation Method to measure the WTP for mitigation strategies.

Expected outputs

  • Understand current awareness and beliefs of urban warming and outdoor habits.

  • Understand people’s perceptions of and preferences for mitigation strategies (population feedback).
  • Assess the willingness to pay for heat mitigation strategies. Estimate a total annual national monetary value of WTP.
  • Develop a statistical model to find the relationship between various parameters.
  • Visualise the spatial distribution of different parameters across Singapore.
  • Identify opportunities for public education and policy implications.
  Fig 1. Conceptual framework of the population survey campaign / Source: Lea Ruefenacht


Fig 1. Conceptual framework of the population survey campaign / Source: Lea Ruefenacht

Links to other tasks:

The Population Survey is a key part of the Cooling Singapore project, helping to develop an understanding of the human behavioural side of the Urban Heat Island effect (UHI) and Outdoor Thermal Comfort (OTC). There are 3 parts of the overall project that look at human aspects:

  • The OTC Measurement Study as on-site measurement and survey of OTC.
  • The Engagement Campaign as on-site workshops with residents.
  • The Population Survey as online survey with representative sample of population.

Summary

This survey joins efforts to understand the behavioural insights of UHI and OTC in Singapore along with the OTC Measurement Study and the Engagement Campaign. We want to evaluate to what extent information can have an impact on attitudes, awareness and beliefs towards urban warning. We are also interested in documenting residents’ preferences and their WTP for the mitigation strategies in order to help governmental agencies to design better public policies.

Engagement campaign

Approach

The impact of the urban heat island effect on the urban microclimate and thermal comfort is an important issue that will affect all residents of Singapore. Therefore, the Engagement Campaign aims to inform and increase awareness about the urban heat island (UHI) effect and outdoor thermal comfort (OTC) in Singapore.

The campaign’s main objectives are:

  1. Engage citizens to obtain direct feedback regarding their thermal perception and choices of actions taken in outdoor spaces
  2. Assess different measures to improve the thermal comfort of their neighborhood.

The campaign will be conducted in HDB estates in collaboration with the local NGO Participate in Design (PiD). A focus group of residents will be selected to participate in the workshops. The collected ideas and feedback during the workshops will be translated into possible strategies. The results will provide future planning and policy recommendations.

Links to other tasks

In parallel to the model-based approach (“Assessment of OTC strategies at local scale”), we also applied an empirical approach to assess the impact of the climate on people’s thermal comfort.

The Measurement Study is directly linked with the “Measurement Study” and the “Population Survey”.

Summary

The Engagement Campaign focuses on studying the relation between climate, urban space and people. The knowledge and insights gained from this campaign directly complemented the modelling and policy-directed research within Cooling Singapore. Citizen engagement is a powerful tool to unfold the qualitative factors of people’s understanding and awareness of the issues surrounding OTC.

 Fig 2. People engagement campaign in cooperation with the Singaporean NGO ‘Participate in Design’ Source: Participate in Design

Fig 2. People engagement campaign in cooperation with the Singaporean NGO ‘Participate in Design’ Source: Participate in Design

Measurement Study

Approach

The outdoor thermal comfort (OTC) has great influence on people’s habits and lifestyles. Therefore, the Measurement Study aims to improve the understanding of OTC in Singapore, especially the climatic and behavioural aspects. The study will investigate how the weather condition and people’s perception influence the use of outdoor spaces.

The main study objectives are:

  1. Identify people’s thermal perception,
  2. Evaluate people’s beliefs towards the environment, and
  3. Assess what physical and social activities people are willing to perform.

In this study, a field survey will be conducted to measure people’s personal condition, thermal perception, beliefs and outdoor activities. In parallel, on-site measurements from weather stations and handheld sensors will measure the weather condition (e.g., temperature, humidity and wind speed). Between 200 and 300 participants will be surveyed.

The collected data will allow for a better understanding of the relationship between quantitative data and qualitative feedback. The feedback will be translated into a statistical model in order to find relationships between the individual parameters. The results will be mapped and visualised in a thermal-activity map. These findings will provide useful information to assess the design of these spaces and its effect on human thermal comfort.

 Fig 3. Measurement Study in Punggol (February 2018), Source: Lina Meisen Photography 2018

Fig 3. Measurement Study in Punggol (February 2018), Source: Lina Meisen Photography 2018

Links to other tasks

In parallel to the model-based approach (“Assessment of OTC strategies at local scale”), we also applied an empirical approach to assess the impact of the climate on people’s thermal comfort.

The Measurement Study is directly linked with the “Engagement Campaign” and the “Population Survey”.

Summary

The Measurement study focuses on identifying the relationship between the climatic conditions, people’s thermal perception, and also people’s environmental attitudes and beliefs. The goal was to understand how these factors impact people’s decisions on what outdoor spaces to use and what physical activities to perform outdoors.