Introduction to Heatwave Meteorology
A heatwave is a wave that occurs when the weather temperature is usually hot and prolonged compared to the normal day's expected heat. Heatwaves may extend up to several days and weeks and the crucial causes of weather-related mortality, affecting both developing and developed countries at the same time. The heatwave meteorology research states that heat waves occur when the daily maximum temperature for more than five continuous days exceeds the maximum temperature by 9 degrees Fahrenheit.
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Intensity and Frequency of Heatwaves
All around the world, the intensity and frequency of heatwaves are keenly observed with the occurring climatic changes. Such weather circumstances may be characterized by low or high humidity; it may cause aggravate drought, health effects of heat-related stress, including dehydration, heat exhaustion, and heatstroke.
Impact of Heatwaves on Environment
Heat Waves can be very dangerous and harmful if people are not prepared for disastrous circumstances. According to the weather forecast heatwave met office, records were broken of over 8000 temperatures in July 2012 in the United States, giving rise to the number of deaths due to the heatwaves.
The World Health Organization (WHO) evaluated that in the year between 2000 and 2016, numerous public exposure to the heatwaves has been increased to 125 million people. In 2003, the heatwave destroyed a maximum of 70,000 people. Lastly, in the year 2010 in Russian Federation, 40,000 people were killed due to the heatwave.
Heatwaves also give rise to health effects that can sometimes be untreatable, and it is discussed below:
A. Mortality
Heatwave is not an issue because it affects global warming, but it is problematic from a mortality point of view. As the mortality rate rapidly increases with experiencing the heatwaves, it will worsen as the heatwave gets more extreme. Some studies state that the winter milder condition will minimize the mortality rates, resulting in a balance or even a decreasing number of deaths.
Agency for health care research and quality reports that 6,200 Americans are admitted into the hospitals each summer due to the excessive heat waves. It is intolerable for elderly persons, and in the year 2003, Europeans lost 70,000 people due to the heatwave.
B. Power Breakdown:
Electricity spike is the other issue caused due to heatwaves. The excessive usage of air conditioners can create a power breakdown, aggravating the problem. The electricity demand is due to the hot and humid temperatures, which are sometimes intolerable at their peaks. When the heatwaves keep extending for more than three days or more, the thermal mass of the buildings detains the heat from the previous days and prevents the nighttime temperature from cooling down. As a result of more air usage, conditioner leads to high electricity consumption causing the electricity outage.
What Causes a Heatwave?
Heatwaves are the result of the surrounding air. Usually, air surrounds the globe in large persuading winds; therefore, it is permitted to warm the atypical temperatures due to sunlight if surrounded by one region. Often the air is surrounded due to high-pressure systems. These systems compel the air downwards, in effect acting as a large-cap. The air is being surrounded and covered. It cannot rise into the cooler upper temperature, which further prevents the dropping rainfall.
How to Stay Safe At Heatwave Meteorology Circumstances
Drink an enormous amount of water during a heatwave
Do not stay in a car for a prolonged time unless it has an air conditioner working in it.
To wear appropriate clothes.
Do not expose much to the sun. Avoid taking sunbathes as sunburn makes it difficult for the public to cool off.
Heatwaves are dangerously unsafe and risk to the people with more population.
Heatwaves are not credited to the same hazardous level as cyclones and tornadoes. Due to the lack of precaution, many underestimate its effects and aggravate the problem. It is especially a risk to the public having susceptible to pre-existing conditions.
FAQs on Heatwave
1. What is a heatwave and what causes it to occur?
A heatwave is a prolonged period of excessively hot weather, which may be accompanied by high humidity, relative to the expected climate conditions for that area at that time of year. The primary meteorological cause is a high-pressure system that settles over an area. This system acts like a dome, trapping air and compressing it, which causes it to warm. The sinking air also prevents cloud formation, leading to more direct sunlight and further increasing temperatures over several days.
2. How does the India Meteorological Department (IMD) declare a heatwave in different parts of India?
The India Meteorological Department (IMD) uses specific temperature criteria to declare a heatwave, which vary by region. A heatwave is generally declared if the condition persists for at least two consecutive days. The main criteria are:
- For Plains: The maximum temperature must reach at least 40°C.
- For Hilly Regions: The maximum temperature must reach at least 30°C.
- For Coastal Regions: The maximum temperature must reach at least 37°C.
A 'severe' heatwave is declared if the temperature is 6.5°C or more above the normal temperature, or if the actual maximum temperature reaches or exceeds 47°C.
3. What is the difference between a heatwave and a normal spell of hot summer weather?
While both involve high temperatures, a heatwave is different from a typical hot day in three key ways:
- Duration: A heatwave is a prolonged event, lasting for several consecutive days, whereas a hot spell can be just one or two days.
- Intensity: A heatwave is defined by temperatures that are significantly above the historical average for a specific location and time of year, not just subjectively hot.
- Impact: The extended duration of a heatwave creates cumulative stress on human health, power grids, water resources, and agriculture, which is far more severe than the impact of a single hot day.
4. How does climate change influence the frequency and intensity of heatwaves?
Climate change significantly increases the likelihood and severity of heatwaves. As global average temperatures rise due to greenhouse gas emissions, the baseline temperature becomes higher. This means that natural temperature variations more easily and frequently cross the threshold into 'extreme heat'. Furthermore, climate change can alter atmospheric circulation patterns, such as the jet stream, making it more likely for high-pressure systems (heat domes) to stall over a region for extended periods, leading to longer and more intense heatwaves.
5. What are the major environmental and economic impacts caused by a heatwave?
Heatwaves have severe environmental and economic consequences. Environmental impacts include increased risk of wildfires, severe stress on water bodies leading to water shortages, and damage to natural ecosystems and biodiversity. Economic impacts are widespread, including major losses in agriculture due to crop failure, a surge in electricity demand for cooling that can strain power grids and cause outages, and a significant decrease in labour productivity, especially in outdoor sectors like construction and farming.
6. Why are urban areas often hotter than surrounding rural areas during a heatwave?
Urban areas experience higher temperatures than their rural surroundings due to the Urban Heat Island (UHI) effect, which is intensified during a heatwave. This happens because cities have a high concentration of materials like concrete, asphalt, and dark rooftops that absorb and retain more solar radiation than natural surfaces like soil and vegetation. Additionally, the lack of green spaces (which provide cooling through transpiration) and waste heat generated from vehicles, air conditioners, and industrial processes all contribute to making cities significantly hotter.
7. Which regions in India are most vulnerable to heatwaves and what are the geographical factors involved?
The most vulnerable regions in India form a core heatwave zone across the northwestern, central, and east-central parts of the country, including states like Rajasthan, Punjab, Haryana, Delhi, Uttar Pradesh, and parts of Madhya Pradesh and Maharashtra. The key geographical factors making these areas prone to heatwaves are:
- Continental Location: These regions are far from the moderating influence of the sea, leading to greater temperature extremes.
- Pre-Monsoon Dryness: The period from March to June is characterized by dry land and clear skies, allowing for maximum solar heating.
- Air Mass Influence: The prevailing hot, dry continental air masses from the west and northwest dominate the weather during this season before the onset of the monsoon.
8. What are some of the key safety measures and precautions students should know to handle a heatwave?
To stay safe during a heatwave, it is important to take several precautions. The most important is to stay hydrated by drinking plenty of water, even if you don't feel thirsty. Other key measures include:
- Avoiding outdoor activities during the hottest part of the day (typically noon to 4 PM).
- Wearing lightweight, light-coloured, and loose-fitting cotton clothes.
- Using a hat, umbrella, or damp cloth to protect your head from direct sun when outside.
- Recognizing the signs of heat stress, such as dizziness, heavy sweating, and nausea, and seeking a cool place or medical help immediately if they occur.
