When regular torrential showers change the weather for good, it is a new lease of life. Monsoon season runs from June to September, and during that time India gets 70 to 80 percent of its annual rainwater.
Two consecutive years of drought in and , for instance, led to crop failures, school closures, drinking-water shortages and over reported deaths from heatstroke. The prevalence of farmer suicides in India is tragic but not surprising. Reuters explains that bad monsoons cause India to import more food, resulting in inflation.
A bad monsoon, and even predictions for a bad monsoon, can also dissuade foreign investors from targeting India. There are other areas of economic concern related to monsoons.
Thanks to modern irrigation technologies, shifts in the timing of the monsoon no longer mean famine, but they do affect the Indian government's bottom line. The South Asian monsoon is a system of winds that reverse direction at roughly the same time every year. As they move up and down the Indian subcontinent, these winds carry fresh water to hundreds of millions of farmers. Consequently, the usually highly predictable monsoon rains are the lifeblood of agriculture throughout the Indian subcontinent.
The monsoon has two phases. The first carries moisture from the Arabian Sea up through the Indian subcontinent. It begins in June and covers most of India with rain until September. In late September, these winds reach the Himalayas and make an abrupt about-face. From late October to December, the monsoon glides back down over the subcontinent on its way to the Indian Ocean.
The two-phase pattern of the winds defines Indian agriculture, so when the pattern shifts even slightly, it can have real implications for food production. In the past, seasonal fluctuation was a matter of life or death for Indian farmers. A bad year meant widespread famine.
Today, the situation is somewhat different. Powered by. A monsoon is a seasonal change in the direction of the prevailing, or strongest, winds of a region.
Monsoons cause wet and dry seasons throughout much of the tropics. Monsoons are most often associated with the Indian Ocean. Monsoons always blow from cold to warm regions. The summer monsoon and the winter monsoon determine the climate for most of India and Southeast Asia.
Summer Monsoon. The summer monsoon is associated with heavy rainfall. It usually happens between April and September. The summer monsoon brings a humid climate and torrential rainfall to these areas. India and Southeast Asia depend on the summer monsoon. Agriculture , for example, relies on the yearly rain. Many areas in these countries do not have large irrigation systems surrounding lakes, rivers, or snowmelt areas. Aquifer s, or supplies of underground water, are shallow.
The summer monsoon fills well s and aquifers for the rest of the year. The start of rains in early June marked the end of the dry winter and the onset of the wet summer monsoon. Mumbai, India, during monsoon rainfall. Image: Indranibasu. Monsoons produce the very wet summers and dry winters that occur on nearly all of the tropical continents.
A monsoon is not a storm like a hurricane or a summer thunderstorm, but a much larger pattern of winds and rain that spans a large geographic area — a continent or even the entire globe. Weather and climate are very different in the tropics and mid-latitudes, and it is not just a matter of the tropics being warmer. In Europe, North America, and other mid-latitude regions, temperatures undergo large changes over the seasonal cycle; weather events in these regions last a few days as high- and low-pressure systems drift slowly eastward, rearranging the locations of warmer and colder air masses as they go.
This might make it cool and rainy one day and warm and sunny the next. The seasonal cycle over tropical continents is marked by an oscillation between dry and wet periods brought about by monsoons. Weather events in the tropics — such as typhoons, thunderstorms, and other rainstorms — are actually embedded within the much larger monsoons. Billions of people live in the monsoon climates of South Asia, Africa, and the tropical Americas, and every spring they wait for monsoon rains that will end the winter dryness even though they might also cause disastrous floods.
There is often too little water or too much. However, monsoons are not the same throughout the tropics, because the specific locations of continents and oceans influence the regional patterns of winds and rain. Classic conditions for strong monsoons are found where the Indian Ocean and the Pacific Ocean meet.
This region includes India and South Asia to the north of the equator and Australia south of the equator. Strong swings between wet summers and dry winters are found in those places as the ITCZ moves back and forth across the equator. The South Asian monsoon, which includes the Indian monsoon, is especially strong because the Himalayas and other mountains block dry air in the north from getting to the humid monsoon region. The seasonally wet and dry region just south of the Sahara Desert in West Africa and the Sahel is another classic monsoon region.
Monsoons occur in the Americas too, but tend to be weaker than in other regions. The animated map below shows how precipitation varies through a typical year.
Notice that most precipitation occurs in the tropics and swings north and south of the equator with the seasons. This seasonal shift in the location of tropical precipitation indicates a shift in the location of the ITCZ and is the reason why there are distinct wet and dry seasons on tropical continents. Patterns of precipitation through the year Image: University of Oregon.
From December until February, the monsoon rains move south of the equator towards Australia while South Asia experiences dry monsoon conditions. There is even an East Asian monsoon that brings summer rain to China, Japan, and Korea, but it is caused by a different type of wind pattern associated with the jet stream. Monsoons bring large amounts of rain to a location, often leading to large-scale vegetation growth. Image: University of Oregon.
Monsoon winds in the tropical parts of North America, Central America, and South America cause the amount of rainfall to vary with the seasons, even in areas where precipitation is plentiful and rainforests thrive. From June to August, which are summer months in the Northern Hemisphere, there is more rainfall north of the equator in Costa Rica, Nicaragua, Panama, and western Mexico. From December to February there is more rainfall south of the equator in Brazil. The North American monsoon does bring moisture from the warm waters of the Pacific into the U.
Southwest, but its peak rainfall occurs in Mexico, and the U. These areas are typically dry but can receive enough rainfall to quell a wildfire if moist monsoon winds blow in summer. An area of summer rainfall along the U. East Coast is associated with what some might call a mid-latitude version of monsoon rainfall.
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