Heat Index
- The India Meteorological Department (IMD) is planning to introduce a ‘heat index’ warning system in Delhi and other parts of the country.
What is Heat Index
- An index that combines air temperature and relative humidity in shaded areas to put forward a human perceived equivalent temperature.
- There are different terms given to Heat Index:
- Felt Air Temperature
- Apparent Temperature
- Real Feel
- The concept Head Index was developed in 1978 by George Winterling
- US National Weather Service adopted it in 1979
What are Recent Studies of IMD Suggests?
- The IMD has conducted a study on the impact of meteorological factors on heatwaves and the “heat wave hazard zonation” of the country.
- According to "Hot Weather Analysis over India," IMD revealed that the mechanism by which heat impacts humans is complex; it is a result of the interactions between temperature, radiation, wind, and humidity.
What is a Heatwave?
- Heat waves are prolonged periods of excessively hot weather that may be accompanied by high humidity, often leading to a range of negative impacts on human health and the environment.
- The heat wave is considered if the maximum temperature of a station reaches at least 40°C for Plains and at least 30°C for Hilly regions.
How to Determine Heat Index?
- It can be calculated using a H index graph or using a H index formula when relative humidity and temperature are known.
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Factors Responsible for Delhi’s Higher Temperature than its Actual Value
- Urban Heat Island Effect
- Air Pollution
- Lack of Water Bodies in Close Proximity
Difference between Hazard, Risk, Vulnerability and Disasters
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What are the different alerts as per the Heat Index?
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