Heat risk map of Riyadh

The dataset is used to assess the urban heat risk in the city of Riyadh using proxy variables to evaluate the environmental, infrastructural, and social dimensions of the city.

The environmental component was evaluated using the mean values of land surface temperature (LST), air temperature (T2m), and discomfort index (DI) across the districts of Riyadh. These factors, derived from data like MODIS LST and available WRF simulations, represented the degree of heat exposure in different regions. 

The infrastructural component of heat risk was evaluated by looking at the city's infrastructure, that is the building density per district. Buildings can act as "heat traps," thus higher building density suggests increased heat risk.

The social component considered demographic factors such as the percentage of the population over 65 old (OP) and under 14 years old (YP), which can indicate sensitivity to extreme heat conditions. 

To map the heat risk, these components were combined into a composite heat risk indicator. For this to be achieved, each parameter was reclassified into three categories (1-less, 2-moderate, and 3-high) using the quantile classification which is a data classification method that distributes a set of values into groups that contain an equal number of values. 

                                      LST  (°C)                   DI                     T2m  (°C)                <14 y.o. (%)             >65 y.o (%)                Buildings per sq. m.(BD)

1-Less risk                       <47.2                    <28                         <40.6                       <23                          <1                                      <66

2-Moderate risk       47.2 ≤ LST ≤ 47.9    28≤ DI ≤ 28.2     40.6 ≤ T2m ≤ 40.8       23≤ YP ≤28               1≤ OP ≤ 3                         66≤ BD ≤ 109

3-High risk                      >47.9                    >28.2                       >40.8                        >28                          >3                                     >109

LST: Land Surface Temperature; DI: Discomfort Index; T2m: Air temperature at 2m height; YP<14 y.o.: People under 14 years old; OP y.o.: Older people over 65 years old; 

Since the relative importance of each parameter is unknown, we considered that all parameters contributed equally to the composite heat risk index and the arithmetic values were aggregated. The final value for each district was then reclassified into three categories using the quantile classification method resulting in the final three categories of Urban Heat Risk (Less heat risk, Moderate heat risk, High heat risk)