monsoon Flashcards
What does monsoon mean?
The word Monsoon relates to a seasonal reversal in wind
direction.
This seasonal reversal in winds has a knock on impact upon
the weather that India experiences in terms of humidity,
cloud formation and precipitation.
How are winter monsoons caused?
The overhead sun has moved southwards causing the sea to get hotter than the land reversing the wind direction.
Cool, dry winds blow from the Asian interior. Any moisture has been lost over the Himalayas so India stays dry and experiences drought conditions.
How are summer monsoons caused?
Sun’s energy heats land to temperatures above 28°C (sometimes as high as 50 °C).
Ocean doesn’t heat as much as
1 kg of water takes 3 times more energy to heat than a solid
The ocean is moving so the whole depth needs to be heated for the temperature to change
The hot land heats the air above it so it rises producing a low pressure area
Moist, cooler ocean air is blown in to replace the rising air.
This air is then warmed so it rises, cools, condenses and forms clouds and therefore the monsoon rain
How do monsoons affect agriculture?
Cotton, Maize, Paddy, Soybean, Groundnut, Bajra and Sesame are among the major crops that rely on Monsoon rains. Dairy farms in India also depend on Southwest Monsoon to keep cows healthy and well-fed.
When the monsoon fails, it can have catastrophic impacts as low yields
increase prices leading to other issues (food shortages, poverty etc)
Large parts of the country do not have proper irrigation systems like surrounding lakes, rivers or snowmelt areas. Thus, agriculture largely depends on Monsoon rains, filling wells and aquifers for the rest of the year.
How do monsoons affect settlements?
Settlements have to be designed to cope with both the long dry season and the intense rain.
- Houses have wide overhanging eves – useful to protect against both sun and rain
- streets have deep and wide drains.
- Some houses are built on stilts to be above flood
water levels.
How do monsoons affect health?
Mosquitoes breed in the ephemeral water bodies created by the rains and malaria and dengue fever cases increase.
Typhoid is rare during the dry seasons but increases during the monsoon as foul drains and tanks overflow into fresh water. The same is true for a number of other gastrointestinal infections.
How do monsoons affect the industry?
Industry in Southeast Asia and India relies on Monsoon rains as a great deal of electricity here is produced by hydroelectric power plants, driven by water that is collected during the monsoons.
Electricity is supplied to various sectors and business houses, helping economies of these areas to develop.
Monsoons and climate change?
For many people in India it is the variability of rainfall on shorter time scales that has the biggest impacts – intense heavy rainfall leads to flooding; breaks in the monsoon of a week or more lead to water shortage and agricultural drought.
In 2002 for example, a break in the monsoon rains saw July receiving only about 50% of its normal rainfall, leading to cuts in agricultural output and declining GDP.
Monsoons and flooding?
Very heavy showers can cause great damage. In urban areas like Mumbai, flooding is a common phenomenon. In rural areas, mudslides caused by excessive rain can bury villages and destroy crops.
