thumb|right|An [[Antarctic Automatic Weather Stations Project AWS in Antarctica]]
An automatic weather station (AWS) is an automated version of the traditional weather station, either to save human labor or to enable measurements from remote areas. The system may report in near real time via the Argos System, LoRa and the Global Telecommunications System, or save the data for later recovery.
In the past, automatic weather stations were often placed where electricity and communication lines were available. Nowadays, the solar panel, wind turbine and mobile phone technology have made it possible to have wireless stations that are not connected to the electrical grid or hardline telecommunications network.
- Thermometer for measuring temperature
- Anemometer for measuring wind speed
- Wind vane for measuring wind direction
- Hygrometer for measuring humidity
- Barometer for measuring atmospheric pressure
Some stations can also have
- Ceilometer for measuring cloud height
- Present weather sensor and/or visibility sensor
- Rain gauge for measuring liquid-equivalent precipitation
- Ultrasonic snow depth sensor for measuring depth of snow
- Pyranometer for measuring solar radiation
Unlike manual weather stations, automated airport weather stations cannot report the class and amount of clouds. Also, precipitation measurements are difficult, especially for snow, as the gauge must empty itself between observations. For present weather, all phenomena that do not touch the sensor, such as fog patches, remain unobserved. The change in instrumentation, enclosure and location can lead to a jump in, for example, the measured temperature or precipitation values, which can lead to erroneous estimates of climate trends. This change, and related non-climatic changes, have to be removed by homogenization.
Data-logger
thumb| Data-logger for automatic weather station
The data-logger is the heart of the Automatic Weather Station.<br />
In high quality weather stations, the data-logger may be designed by the supplier to be the perfect solution for a particular meteorological client.
Indeed, usually data-loggers found in the market don't fit the requirement in terms of power consumption, inputs, communication, protection against animals (ants, rats, etc.), humidity, salty air, sand, etc.<br />
The main functions of a data-logger are:
- Measurement: the data-logger collects the information from every sensor and archives it.
- Calculation: the data-logger processes most of the meteorological data for the users (avg, min, max...).
- Data storage: the data-logger saves all the data either on its own memory or on uSD memory card.
- Power supply: the data-logger manages the power supply of the Automatic Weather Station, using a solar panel for instance.
- Communication: the data-logger manages the communication protocols with the remote server. The different communication protocols are usually GSM, GPRS, RTC, WiFi, uSD, and RS-232.
Enclosures
thumb|Enclosure with solar panel for data-logger of weather station
Enclosures used with automatic weather stations are typically weather proof fiberglass, ABS or stainless steel, With ABS being the cheapest, cast aluminium paint or stainless steel the most durable and fiberglass being a compromise. The AWS can be programmed to alert authorities in case of severe weather events.
The accuracy of automatic weather stations varies, largely due to the stations being automated. This causes issues concerning the placement of the station, the margin of error from the installed sensors, frequency of maintenance and calibration errors, much more apparent when there is no involvement from actual professionals from the meteorological field.
See also
- Remote Automated Weather Station
- Automated airport weather station
- Personal weather station
- Mesonet
- Cooperative Observer