Using Citizen Sensing to Identify Heat-Exposed Neighbourhoods

Round 1

Reviewer 1 Report

This is a paper of significance  to urban planners and administrators.  Figure 5 is a good example of how useful information is displayed. The paper is well written with appropiate levels of detail in explanation.  The questions I had at the outset were mainly answered. 

I saw no comment on how different surfaces would absorb or reflect heat, and how that would influence data.  I can guess general answers but wondered which surfaces contributed to the hot spots (bitumen car parks for example).  I did notice that certain surfaces were mentioned as remedy for hot areas (Line 416).

Minor checking required (eg Line 29 "devises" should be "devices" according to my spelling and Line 289 "sufficient" rather than "sufficiently"

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is on an interesting topic for the journal and offers a valuable contribution to the international literature. but the following points need to be addressed:

• Please provide a better definition of heat waves, including also a discussion of how the heat wave interact with the Urban Heat Island phenomenon. There are many references in the literature on this topic. 
• In the introduction, it is said that Apparent Temperature is used as main metric, and then the Humidex Index is proposed. Please better clarify the use of Apparent Temperature and Humidex Index and better clarify why the second has been used.
• Please, clarify if the values included in Figure 4 are referred to the air temperature (wet bulb, dry bulb?) or to the apparent temperature. If the first is presented, it is not clear why the comparison is not given considering the apparent temperature.
• In the discussion, please give a better account of all the factors which could have generated the spatial distribution of the humidex index highlighted in figures 5, and 6. This would include also the role of urban geometry, urban materials and greenery.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The paper is well written and structured. The objectives are correctly identified and clear and can be framed in the recent researchers' attempt to appropriate the tools made available by the web. The methodology used is sufficiently rigorous and the results are consistent with the objectives. The only note concerns the invitation to better clarify what the authors have also expressed graphically with figure 3.

The workflow uses a 6-day sample equivalent to 144 total hours which, appropriately averaged over 24 hours, provide a raster of 24 surface representations. From this point on, the methodological procedure should be better clarified. Only the apparent temperature differences with respect to the threshold of 30 ° C are considered and, subsequently, these differences are added to constitute HDH. What happens if the consecutive days exceeding the critical threshold are more numerous than 6? Is a progressive average carried out?

Author Response

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Author Response File: Author Response.pdf