AMeDAS the automated surface meteorological observation system.

1. CONTENTS
Annual report DVD-ROM contains AMeDAS(Automated Meteorological Data
Acquisition System) 10 Minute values data, hourly data, daily data,
voluntary observation data, monthly statistics data and ranking records.
There are three types of observation in AMeDAS.
4-meteorological element (temperature, precipitation amount,
wind direction and speed, sunshine duration)
Automated snow depth measuring.
Voluntary observation.

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.

Explanation of Snow depth data observed by automated measuring
and voluntary observation

Observation station index
Refer [ /AMEDAS/amdmaster.index ] files for details.

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.