Monsoon in the Vindhya, a mountain chain in central India

A monsoon is a periodic wind, especially in the Indian Ocean and southern Asia. The word is also used to label the season in which this wind blows from the southwest in India and adjacent areas that is characterized by very heavy rainfall, and specifically the rainfall that is associated with this wind. Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... The Vindhya Range is a range of hills in central India, which geographically separates The Indian subcontinent into northern India and Southern India. ... Wind is the quasi-horizontal movement of air (as opposed to an air current) caused by a horizontal pressure gradient force. ... World map showing location of Asia Asia is the central and eastern part of Eurasia, defined by subtracting Europe from Eurasia. ... A season is one of the major divisions of the year, generally based on broad climatic patterns. ... In meteorology, precipitation is any kind of water that falls from the sky as part of the weather. ...

History

The word "monsoon" appears to have originated from the Arabic word "موسم" (mausem), which means season. It is most often applied to the seasonal reversals of the wind direction along the shores of the Indian Ocean, especially in the Arabian Sea, that blow from the southwest during one half of the year and from the northeast during the other. Arabic (العربية al-arabiyyah, or less formally arabi) is the largest member of the Semitic branch of the Afro-Asiatic language family (classification: South Central Semitic) and is closely related to Hebrew and Aramaic. ... Map of the Arabian Sea. ...

The legendary Greek sailor Hippalus was traditionally held to have been the first to use the monsoon to speed across the Indian Ocean; the ancient name for the monsoon wind in this region is also called Hippalus. However, it is more likely that he was simply the first Greek to master the monsoon, as Yemeni sailors were trading with India long before his time. Hippalus was a Greek navigator who probably lived in the 1st century BCE. He is sometimes conjectured to have been the captain of the Greek explorer Eudoxus of Cyzicus ship. ...

Processes

Monsoons are caused by the fact that land heats up and cools down quicker than water. Thus, in summer, land reaches a higher temperature than the ocean. The hot air over the land tends to rise, creating an area of low pressure. This creates an extremely constant wind blowing toward the land. Associated rainfall is caused by the moist ocean air being diverted upward by mountains, which causes cooling, and in turn, condensation. A low, or a low pressure area, is a region of rising atmospheric air. ... In meteorology, precipitation is any kind of water that falls from the sky as part of the weather. ...

In winter, the land cools off quickly, but the ocean retains heat longer. The hot air over the ocean rises, creating a low pressure area and a breeze from land to ocean. Because the temperature difference between the ocean and land is less than in summer, the winter monsoon wind is not as constant.

Monsoons are similar to sea breezes, but they are much larger in scale, stronger, and are more constant. A sea breeze or seabreeze is a thermally-forced mesoscale (i. ...

Monsoon Systems

As monsoons have come to be better understood, the definition has been broadened to include almost all of the phenomena associated with the annual weather cycle within the tropical and subtropical continents of Asia, Australia, and Africa and the adjacent seas and oceans. It is within these regions that the most vigorous and dramatic cycles of weather events on Earth takes place. Composite satellite image showing the progress of a hurricane weather system approaching the east coast of America Weather comprises all the various phenomena that occur in the atmosphere of a planet. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ... Subtropical (or semitropical) areas are those adjacent to the tropics, usually roughly defined as the ranges 23. ... Africa is the worlds second-largest continent and second most populous. ... Earth, also known as the Earth, Terra, and (mostly in the 19th century) Tellus, is the third planet outward from the Sun. ...

Even more broadly, in the geological past, it is now understood, monsoon systems must have always accompanied the formation of supercontinents such as Pangea, with their extreme continental climates. In geology, a supercontinent is a land mass comprising more than one continental core, or craton. ... Map of Pangæa Pangaea (Greek for all lands) is the name Alfred Wegener used to refer to the supercontinent that existed during the Mesozoic era, before the process of plate tectonics separated the component continents. ... A continental climate is the climate typical of the middle-latitude interiors of the large continents of the Northern Hemisphere in the zone of westerly winds; similar climates exist along the east coasts (but not the west coasts) of the same continents, and also at higher elevations in certain other...

North American Monsoon

The North American monsoon occurs from mid July into September and affects Arizona, New Mexico, Nevada, Utah, Colorado, West Texas, and California. It pushes as far west as the Peninsular Ranges and Transverse Ranges of southern California but rarely reaches the coastal strip (a wall of desert thunderstorms only a half-hour's drive away is a common summer sight from the sunny skies along the coast). The North American monsoon is associated an area of high pressure called the subtropical ridge that moves northward during the monsoon season. At the surface, the monsoon is associated with a weak high that forms over the four corners region and a thermal low that forms over Baja California. The Bermuda high also plays some role in the monsoon. The placement of the high and low pressure areas causes the wind to shift from westerly to southerly. Moisture is drawn northward from the Gulf of California into northern Mexico and the Southwest United States. Rainfall during the monsoon occurs as thunderstorms over the southern Rocky Mountains and adjacent areas. This season of almost daily thunderstorms is often called the Southwest, Mexican or Arizona monsoon. It is also sometimes called the Desert Monsoon as a large part of the affected area is desert. As much as 70% of rainfall in the region occurs during the summer monsoon season. Many desert plants are adapted to take advantage of this wet season in the usually dry area. Because of the danger of being caught in the open when these storms suddenly appear, many golf courses in Arizona have thunderstorm warning systems. State nickname: The Grand Canyon State, The Copper State Other U.S. States Capital Phoenix Largest city Phoenix Governor Janet Napolitano (D) Official languages English Only State Area 295,254 km² (6th)  - Land 294,312 km²  - Water 942 km² (0. ... State nickname: Land of Enchantment Other U.S. States Capital Santa Fe Largest city Albuquerque Governor Bill Richardson Official languages English and Spanish Area 315,194 km² (5th)  - Land 314,590 km²  - Water 607 km² (0. ... State nickname: Silver State, Battle Born State (official) Other U.S. States Capital Carson City Largest city Las Vegas Governor Kenny Guinn (R) Official languages None Area 286,367 km² (7th)  - Land 284,396 km²  - Water 1,971 km² (0. ... State nickname: Beehive State Other U.S. States Capital Salt Lake City Largest city Salt Lake City Governor Jon M. Huntsman, Jr. ... This is the article on the state. ... West Texas is a region in Texas which has more in common geographically with the Southwestern United States than it does with East Texas and North Texas. ... State nickname: The Golden State Other U.S. States Capital Sacramento Largest city Los Angeles Governor Arnold Schwarzenegger (R) Official languages English Area 410,000 km² (3rd)  - Land 404,298 km²  - Water 20,047 km² (4. ... The Peninsular Ranges are a group of mountain ranges which stretch 900 miles from southern California to the southern tip of Baja California, part of the North American Coast Ranges that run along the Pacific coast from Alaska to Mexico. ... The Transverse ranges are a group of mountain ranges of southern California, part of the North American Coast Ranges that run along the Pacific coast from Alaska to Mexico. ... A high, or a high pressure area, is a region where the atmospheric pressure is greatest with relation to the surrounding area. ... For other terms of Four Corners, see Four Corners disambiguation The Four Corners is a region in the western United States located near the common border of four states: in clockwise order from the top-left, these are Utah, Colorado, New Mexico and Arizona. ... A low pressure area, or a low for short, is a region where the atmospheric pressure is lowest with relation to the surrounding area. ... Baja California is the northernmost state of Mexico; it is mostly located on the northern half of the Baja California peninsula. ... The Gulf of California (also known as the Sea of Cortez or Sea of Cortés; locally known in the Spanish language as Mar de Cortés or, much less frequently, Golfo de California) is a body of water that separates the Baja California Peninsula from the Mexican mainland. ... The Southwest region of the United States is drier than the adjoining Midwest in weather; the population is less dense and, with strong Spanish-American and Native American components, more ethnically varied than neighboring areas. ... A roll cloud associated with a heavy or severe thunderstorm over Enschede, The Netherlands. ... Rocky Mountain National Park (photo courtesy of NPS) The Rocky Mountains, often called the Rockies, are a broad mountain range in western North America. ...

Northeast Winter Monsoon (Asia)

In Asia, the northeastern winter monsoons take place from December to early March. The temperature over central Asia is lower, creating a zone of high pressure there. The jet stream in this region splits into the southern subtropical jet and the polar jet. The subtropical flow directs northeasterly winds to blow across south Asia, creating dry air streams which produce clear skies over India from the months of November to May. World map showing location of Asia Asia is the central and eastern part of Eurasia, defined by subtracting Europe from Eurasia. ... In many parts of the world, winter is associated with snow. ... December is the twelfth and last month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... March is the third month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... Jet streams are fast flowing, confined air currents found in the atmosphere at around 12 km above the surface of the Earth, just under the tropopause. ... For other uses, see November (disambiguation). ... This article is about the month of May. ...

Meanwhile, a low pressure system develops over northern Australia and winds are directed toward Australia.

During the Northeast Winter Monsoon, Australia and southeast Asia receive large amounts of rainfall.

Southwest Summer Monsoon

The Southwestern Summer Monsoons occur from June to September, after the winds shift during the months of March and May. An area of intense low pressure develops over central Asia, and the jet stream blows over this area. Summer is a season, defined by convention in meteorology as the whole months of June, July and August in the Northern hemisphere and the whole months of December, January and February in the Southern hemisphere. ... June is the sixth month of the year in the Gregorian Calendar and one of four with the length of 30 days. ... September is the ninth month of the year in the Gregorian Calendar and one of four Gregorian months with the length of 30 days. ...

The southeastern winds blow towards the area of low pressure over Asia, passing over Southeast Asia, which experiences large amounts of rainfall in this period. Meanwhile, the southwest monsoon is drawn towards the Himalayas, creating winds blowing rain clouds towards India, which receive up to 10,000 mm of rain in some areas. Location of Southeast Asia Southeast Asia is a subregion of Asia. ... The Himalaya is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau. ...

See also

• Climate of India

This article needs copyediting (checking for proper English spelling, grammar, usage, etc. ...

Reference and external links

• Initial text from the Goddard Space Flight Center's public domain Distributed Active Archive Center
• About the North American Monsoon - Arizona State University
• North American Monsoon Experiment
• Meet the Indian monsoons at PBS.org