AMeDAS the automated surface meteorological observation system.
2. OUTLINE OF
OBSERVATION SYSTEM
AMeDAS (Automated Meteorological Data
Acquisition System) was installed
1st of November 1974, since then over 1300 stations are working
throughout Japan. Observed meteorological elements are
precipitation
amount, wind direction and speed, temperature, sunshine duration
and
snow depth. These hourly data are acquired to the AMeDAS center
in Tokyo.
Together with other observation data, such as meteorological
satellite
and radar, AMeDAS data is used to support tailored forecast and
warning
to mitigate meteorological disasters. And archived historical
data and
statistics are meet the basic information for wide area of human
activities such as decision making, industrial production
planning and
farming schedule.
AMeDAS observation data
Precipitation amount
One hour amount is measured.
Statistics are 1 mm in unit but measured 0.5 mm in unit.
Wind direction and speed
Wind direction is an average of directions from 10 minutes
before observation time and digitized 1 to 16 (1:NNE,02:NE....15:NNW and 16:N)
In case of calm (wind speed is less than 1 m/s) direction is assign 0.
Wind speed is ten minutes average and 1 meter/second in unit.
Temperature
Observed in Celsius degree.
Sunshine duration
Observed by 0.1 hour in unit.
Hourly data
Basic observation data of AMeDAS to
provide daily and monthly statistics.
Precipitation amount and sunshine duration are obtained by difference
of accumulating counter and wind direction/speed and temperature are
measured value.
Daily data
Daily precipitation and sunshine
duration are accumulated value, and
wind speed and temperature are mean of hourly observations.Extremes
are one hour maximum precipitation amount, maximum wind speed and
maximum/minimum temperature obtained at intervals of 10 minutes.