Future Heat Stress Indicators for Johannesburg and Ekurhuleni

This dataset is part of the scientific paper: Souverijns, N., De Ridder, K., Veldeman, N., Lefebre, F., Kusambiza-Kiingi, F., Memela, W., Jones, N.K.W., 2022. Urban heat in Johannesburg and Ekurhuleni, South Africa: A meter-scale assessment and vulnerability analysis. Urban Climate, 46, 101331. https://doi.org/10.1016/j.uclim.2022.101331

Heat stress indicators for present and future climates for the cities of Johannesburg and Ekurhuleni (South Africa).at 30m spatial resolution calculated with UrbClim (De Ridder et al., 2015) for the following scenarios:

- 2001-2020: present time (ERA5 input data)

- 2021-2040 RCP4.5 (CMIP5 ensemble)

- 2021-2040 RCP8.5 (CMIP5 ensemble)

- 2041-2060 RCP4.5 (CMIP5 ensemble)

- 2041-2060 RCP8.5 (CMIP5 ensemble)

For each of the 23 indicators, an overview image is available at high resolution. Furthermore, georeferenced GeoTiffs are available to visualize & analyse the indicators on the users preferred system. The indicators are available in EPSG4326/WGS84. A description of each indicator is given:

- Cooling degree hours: Annual number of hours during which the temperatures rises over 25°C, multiplied by the number of degrees the temperature rises above 25°C. This is an international standard to estimate the energy demand for air conditioning use.

- CSDI: Cold spell duration index. Annual number of days with at least six consecutive days when the night temperature < 10th percentile

- Heatwave days: Number of heatwave days per year calculated following the definition of the South African Weather Service. If the maximum temperature at a particular town is expected to meet or exceed 5 degrees C above the average maximum temperature of “the hottest month” for that particular place (this is 32°C for Johannesburg & Ekurhuleni), as well as persisting in that mode for 3 days or more (https://www.weathersa.co.za/home/weatherques)

- T2M_daily_mean_max: Average daily maximum temperature

- T2M_daily_mean_max_topography: Daytime Urban Heat Island corrected for topography

- T2M_daily_mean_min: Average daily minimum temperature

- T2M_daily_mean_min_topography: Nighttime Urban Heat Island corrected for topography

- T2M_dayover25: Annual number of days attaining a maximum temperature > 25°C

- T2M_dayover25_duetourban: Annual number of days attaining a maximum temperature > 25°C that are caused by urban canopy

- T2M_dayover30: Annual number of days attaining a maximum temperature > 30°C

- T2M_dayover30_duetourban: Annual number of days attaining a maximum temperature > 30°C that are caused by urban canopy

- T2M_max: Absolute maximum temperature

- T2M_mean: Absolute average temperature

- T2M_min: Absolute minimum temperature

- T2M_nightover20: Number of nights attaining a minimum temperature not dropping below 20°C

- T2M_nightover25: Number of nights attaining a minimum temperature not dropping below 25°C

- TN10P: Annual number of days when the night temperature < 10th percentile

- TN90P: Annual number of days when the night temperature > 90th percentile

- TN_max: Annual minimum nighttime warmest temperature

- TX10P: Annual number of days when the day temperature < 10th percentile

- TX90P: Annual number of days when the day temperature > 90th percentile

- TX_min: Annual maximum daytime coolest temperature

- WSDI: Warm Spell Duration Index. Annual number of days with at least six consecutive days when daytime temperatues > 90th percentile