East Asian monsoon

East Asian monsoon

Discussion
Ask a question about 'East Asian monsoon'
Start a new discussion about 'East Asian monsoon'
Answer questions from other users
Full Discussion Forum
 
Encyclopedia
The East Asian monsoon is a monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...

al flow that carries moist air from the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

 and Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 to East Asia
East Asia
East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...

. It affects approximately one-third of the global population, influencing the climate of Japan (including Okinawa), the Koreas, Taiwan, Hong Kong, Macau, and much of mainland China. It is driven by temperature differences between the Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

n continent and the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

. The East Asian monsoon is divided into a warm and wet summer monsoon and a cold and dry winter monsoon. This cold and dry winter monsoon is responsible for the aeolian dust deposition and pedogenesis
Pedogenesis
Pedogenesis is the science and study of the processes that lead to the formation of soil ' and first explored by the Russian geologist Vasily Dokuchaev , the so called grandfather of soil science, who determined that soil formed over time as a consequence of...

 that resulted in the creation of the Loess Plateau
Loess Plateau
The Loess Plateau , also known as the Huangtu Plateau, is a plateau that covers an area of some 640,000 km² in the upper and middle reaches of China's Yellow River. Loess is the name for the silty sediment that has been deposited by wind storms on the plateau over the ages...

.

In most years, the monsoonal flow shifts in a very predictable pattern, with winds being southeasterly in late June, bringing significant rainfall to the Korean peninsula
Korean Peninsula
The Korean Peninsula is a peninsula in East Asia. It extends southwards for about 684 miles from continental Asia into the Pacific Ocean and is surrounded by the Sea of Japan to the south, and the Yellow Sea to the west, the Korea Strait connecting the first two bodies of water.Until the end of...

 and Japan (in Taiwan and Okinawa this flow starts in May). This leads to a reliable precipitation spike in July and August. However, this pattern occasionally fails, leading to drought and crop failure. In the winter, the winds are northeasterly and the monsoonal precipitation bands move back to the south, and intense precipitation occurs over southern China and Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...

.

The East Asian monsoon is known as jangma (장마) in Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...

. In Japan the monsoon boundary is referred to as the bai-u as it advances northward during the spring, while it is referred to as the shurin when the boundary retreats back southward during the autumn months. Over Japan and Korea, the monsoon boundary typically takes the form of a quasi-stationary front
Stationary front
A stationary front is a boundary between two different air masses, neither of which is strong enough to replace the other. On a weather map, this is shown by an inter-playing series of blue spikes pointing one direction and red domes pointing the other. They tend to remain essentially in the same...

 separating the cooler air mass associated with the Okhotsk High
Okhotsk High
Semi-permanent high pressure system that forms over the Sea of Okhotsk during the summer months. Its associated air mass is maritime polar, marked with frequent sea fog over ocean areas, and cool and moist conditions over land. It typically dominates the weather pattern over eastern Russia,...

 to the north from the hot, humid air mass associated with the subtropical ridge
Subtropical ridge
The subtropical ridge is a significant belt of high pressure situated around the latitudes of 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. It is characterized by mostly calm winds, which acts to reduce air quality under its axis by causing fog overnight, and haze during...

 to the south. After the monsoon boundary passes north of a given location, it is not uncommon for daytime temperatures to exceed 32 °C (90 °F) with dewpoints of 24 °C (75 °F) or higher.

See also


External links