HEAT INDEX
CONTEXT:
- Next year, India to launch its own heat index next year to quantify heat hazard, generate impact-based heat wave alerts for specific locations.
WHAT IS HEAT INDEX ?
- The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.
- The heat index (HI) is an index that combines air temperature and relative humidity, in shaded areas, to posit a human-perceived equivalent temperature, as how hot it would feel if the humidity were some other value in the shade.
- The result is also known as the “felt air temperature”, “apparent temperature”, “real feel” or “feels like”.
- This has important considerations for the human body’s comfort. When the body gets too hot, it begins to perspire or sweat to cool itself off.
Differences from the US Heat Index
- One major difference between the heat index of the US and India’s heat hazard score is that the latter will consider other parameters that aggravate heat situations such as minimum temperature, wind, and exposure duration.
EFFECTS OF THE HEAT INDEX:
| Celsius | Notes |
| 27–32 °C | Caution: fatigue is possible with prolonged exposure and activity. Continuing activity could result in heat cramps. |
| 32–41 °C | Extreme caution: heat cramps and heat exhaustion are possible. Continuing activity could result in heat stroke. |
| 41–54 °C | Danger: heat cramps and heat exhaustion are likely; heat stroke is probable with continued activity. |
| over 54 °C | Extreme danger: heat stroke is imminent. |
- Exposure to full sunshine can increase heat index values by up to 8 °C (14 °F).
- The research article, published in the journal PLOS Climate, notes that the heat index figures recorded across Delhi in April last year are in the ‘danger’ category of the United States National Weather Service classification for heat index, based on the effect of heat on the human body.
- The ‘danger’ category points to the likelihood of heat cramps and heat exhaustion, along with possible heat stroke in case of continued activity. There is only one higher category of ‘extreme danger’ when heat stroke is “imminent,” according to the classification.
SYLLABUS: PRELIMS, ENVIRONMENT
SOURCE: WIKI
