East Asian rainy season
Encyclopedia
The East Asian rainy season, commonly called the plum rain (Chinese
: 梅雨, méiyǔ; ; ), is caused by precipitation
along a persistent stationary front
known as the Meiyu front for nearly two months during the late spring
and early summer
between eastern China
, Taiwan
, South Korea
, and Japan
. The wet season
ends during the summer when the subtropical ridge
becomes strong enough to push this front north of the region.
The weather front forms when the moist air over the Pacific meets the cooler continental air mass
. The front and the formation of frontal depressions
along it brings precipitation to Japan, Korea, eastern China, and Taiwan. As the front moves back and forth depending on the strength of cool and warm air masses, there is often prolonged precipitation and sometimes flooding in eastern China
. However, in the years that it does not rain as much as usual, a drought might result. The rainy season ends when the warm air mass associated with the subtropical ridge is strong enough to push the front north and away.
in the air during this season encourages the formation of mold
and rot
not only on food but on fabrics as well.
Environmentally, heavy rains encourage mudslides and flooding in all areas affected. The most rain in a one-hour period as recorded in Japan was in Nagasaki
in 1982 with 153 mm. The highest overall recorded rainfall during the rainy season in Japan 2003, Miyazaki Prefecture
recorded rains of 8670 mm.
)") on account of the timing. The enka
artist Eiichi Ōtaki produced a popular song by this name, and a WW2 Japanese naval ship
was also given this name.
The rains in the middle of November - Early December are often called Sazanka Tsuyu, literally "rainy season of the Camellia
" on account of the timing with the blossoming of the seasonal flower.
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
: 梅雨, méiyǔ; ; ), is caused by precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
along a persistent 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...
known as the Meiyu front for nearly two months during the late spring
Spring (season)
Spring is one of the four temperate seasons, the transition period between winter and summer. Spring and "springtime" refer to the season, and broadly to ideas of rebirth, renewal and regrowth. The specific definition of the exact timing of "spring" varies according to local climate, cultures and...
and early summer
Summer
Summer is the warmest of the four temperate seasons, between spring and autumn. At the summer solstice, the days are longest and the nights are shortest, with day-length decreasing as the season progresses after the solstice...
between eastern China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, 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...
, South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
, and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. The wet season
Wet season
The the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...
ends during the summer when 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...
becomes strong enough to push this front north of the region.
Formation
An east-west zone of disturbed weather during spring along this front stretches from the east China coast, initially across Taiwan and Okinawa, later, when it has shifted to the north, eastward into the southern peninsula of South Korea and Japan. The rainy season usually lasts from May to June in Taiwan and Okinawa, from June to July (approximately 50 days) in Japan and Korea and from July to August in Eastern China (especially the Chang Jiang and Huai He regions).The weather front forms when the moist air over the Pacific meets the cooler continental air mass
Air mass
In meteorology, an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of square miles, and adopt the characteristics of the surface below them. They are classified according to latitude and their continental or maritime...
. The front and the formation of frontal depressions
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
along it brings precipitation to Japan, Korea, eastern China, and Taiwan. As the front moves back and forth depending on the strength of cool and warm air masses, there is often prolonged precipitation and sometimes flooding in eastern China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. However, in the years that it does not rain as much as usual, a drought might result. The rainy season ends when the warm air mass associated with the subtropical ridge is strong enough to push the front north and away.
Effects
The high humidityHumidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
in the air during this season encourages the formation of mold
Mold
Molds are fungi that grow in the form of multicellular filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeasts...
and rot
ROT
The aviation term ROT stands for rate one turn, also known as a standard rate turn. All aircraft must be able to perform a standard rate turn....
not only on food but on fabrics as well.
Environmentally, heavy rains encourage mudslides and flooding in all areas affected. The most rain in a one-hour period as recorded in Japan was in Nagasaki
Nagasaki
is the capital and the largest city of Nagasaki Prefecture on the island of Kyushu in Japan. Nagasaki was founded by the Portuguese in the second half of the 16th century on the site of a small fishing village, formerly part of Nishisonogi District...
in 1982 with 153 mm. The highest overall recorded rainfall during the rainy season in Japan 2003, Miyazaki Prefecture
Miyazaki Prefecture
is a prefecture of Japan located on the island of Kyushu. The capital is the city of Miyazaki.- History :Historically, after the Meiji Restoration, Hyūga Province was renamed Miyazaki Prefecture....
recorded rains of 8670 mm.
Japan
In Japan, the season is occasionally called Samidare (written: 五月雨 literally "5th month Rain (in Japanese traditional calendarLunar calendar
A lunar calendar is a calendar that is based on cycles of the lunar phase. A common purely lunar calendar is the Islamic calendar or Hijri calendar. A feature of the Islamic calendar is that a year is always 12 months, so the months are not linked with the seasons and drift each solar year by 11 to...
)") on account of the timing. The enka
Enka
is a popular Japanese music genre considered to resemble traditional Japanese music stylistically. Modern enka, however, is a relatively recent musical form which arose in the context of such postwar expressions of modern Japanese nonmaterial nationalism as nihonjinron, while adopting a more...
artist Eiichi Ōtaki produced a popular song by this name, and a WW2 Japanese naval ship
Japanese destroyer Samidare
was the sixth of ten destroyers, built for the Imperial Japanese Navy under the Circle One Program .-History:The Shiratsuyu class destroyers were modified versions of the , and were designed to accompany the Japanese main striking force and to conduct both day and night torpedo attacks against the...
was also given this name.
The rains in the middle of November - Early December are often called Sazanka Tsuyu, literally "rainy season of the Camellia
Camellia sasanqua
The Christmas Camellia is a species of Camellia native to the evergreen coastal forests of southern Japan in Shikoku, Kyūshū and many other minor islands as far south as Okinawa. It is usually found growing up to an altitude of 900 metres.It is an evergreen shrub growing to 5 m tall...
" on account of the timing with the blossoming of the seasonal flower.