Daily Current Affairs Update: 4th April, 2023

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.

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

What are the different alerts as per the Heat Index?