An automatic weather station (AWS) is a facility that measures, records, and transmits meteorological variables autonomously and continuously, without the need for a human observer on site. AWSs have revolutionised meteorological observation by enabling unprecedented spatial and temporal coverage, with data every 10 minutes (or less) around the clock.
Sensors and variables
A standard AWS includes sensors for: temperature and humidity (thermohygrometer in a ventilated screen), atmospheric pressure (digital barometer), wind (anemometer and wind vane at 10 m), precipitation (tipping-bucket or weighing rain gauge), solar radiation (pyranometer), and in advanced stations: ceilometer, visibility sensor, precipitation type detector, and ground state sensor.
Data is transmitted in real time via GPRS/3G/4G, satellite, or radio to the meteorological service's data centre, where it undergoes automatic quality control checks before being incorporated into numerical weather prediction models. AWSs operate on solar power and batteries, allowing installation in remote locations (mountain summits, islands, desert areas).
In Spain, AEMET operates a network of more than 800 AWSs distributed across the entire territory, complemented by over 2,500 stations in the collaborative climatological network. This network is the backbone of Spanish meteorological observation. See also: barometer, thermometer, meteorological lidar.