AMeDAS (''A''utomated ''Me''teorological ''D''ata ''A''cquisition ''S''ystem), commonly known in Japanese as "アメダス" (''amedasu''), is a high-resolution surface observation network developed by the

Japan Meteorological Agency The , abbreviated JMA, is an agency of the Ministry of Land, Infrastructure, Transport and Tourism. It is charged with gathering and providing results for the public in Japan that are obtained from data based on daily scientific observation an ...

(JMA) used for gathering regional weather data and verifying forecast performance. The system began operating on 1 November 1974, and currently comprises 1,300 stations throughout Japan (of which over 1,100 are unmanned), with an average separation of . Observations at manned stations cover weather, wind direction and

speed In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quanti ...

, types and amounts of

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

types Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Typ ...

and base heights of clouds,

visibility The visibility is the measure of the distance at which an object or light can be clearly discerned. In meteorology it depends on the transparency of the surrounding air and as such, it is unchanging no matter the ambient light level or time of ...

, air temperature,

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

sunshine duration Sunshine duration or sunshine hours is a climatological indicator, measuring duration of sunshine in given period (usually, a day or a year) for a given location on Earth, typically expressed as an averaged value over several years. It is a gene ...

, and

atmospheric pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...

. All of these (except weather, visibility and cloud-related meteorological elements) are observed automatically. At unmanned stations, observations are performed every 10 minutes. About 700 of the unmanned stations observe precipitation, air temperature, wind direction and speed, and sunshine duration, while the other stations observe only precipitation. For about 280 stations (manned or unmanned) located in areas of heavy snowfall, snow depth is also observed. All the observational data is transmitted to the AMeDAS Center at JMA Headquarters in Tokyo on a

real time Real-time or real time describes various operations in computing or other processes that must guarantee response times within a specified time (deadline), usually a relatively short time. A real-time process is generally one that happens in defined ...

basis via dedicated telephone lines. The data is then delivered to the whole country after a quality check. As well as weather conditions, AMeDAS is also used in the observation of

natural disaster A natural disaster is "the negative impact following an actual occurrence of natural hazard in the event that it significantly harms a community". A natural disaster can cause loss of life or damage property, and typically leaves some econ ...

s. Temporary observation points are set up in areas where there are signs of

volcanic eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...

s or earthquakes.

External links

Japan Meteorological Agency observations descriptions
Geography of Japan Japan Meteorological Agency Meteorological data and networks Meteorological instrumentation and equipment Science and technology in Japan {{Climate-stub

See also

External links