The Met Office's Marine Automatic Weather Stations (MAWS) network consists of 11 moored buoys and seven systems on lightships and islands. Nine of the buoys are in open-ocean locations — seven to the west of the British Isles and two (which are owned jointly with the French Met. Service Meteo-France) in the Bay of Biscay — and two are in coastal inshore waters.
Each buoy contains two cross-linked Automatic Weather Stations (AWS) which measure air pressure; air and sea temperature; humidity; wind speed and direction, and wave height and period. This cross-linking is designed to make the buoys systems resilient to individual component failures — the buoys have demonstrated their resilience very well over the last 10 years. They are solar powered using twin panels, but will run for around three months on batteries alone. Out of the water each buoy is 6 m tall, 3 m in diameter, and weighs 4.5 tonnes.
The buoys are designed to operate in the extreme environment of the north eastern Atlantic. During winter 2007/8 our moored buoy network recorded several extreme wave events. In December the K3 buoy measured a significant wave height of 18.2 m and in March K2 measured a wave height of 17.6 m — the two highest wave events ever recorded by the network. The maximum wave heights (crest to trough) were probably several times higher than the significant wave height. Observations suggest the incidence of severe wave conditions in the north-east Atlantic is increasing and the buoy network provides key time series to monitor these changes.
The stations transmit their observations hourly — 24 hours a day, 365 days a year. The data are currently used to help us:
Lightships are permanently-moored ships that have light beacons mounted on them. Some also have Automatic Weather Stations. The lightship systems take the same range of measurements as the moored buoys, with the addition of visibility.
We also operate Automatic Weather Stations on three remote Scottish Islands — Foula, North Rona and Sule Skerry.
The island systems make most of the same measurements as the other systems, but because they are land based they do not measure sea temperature or waves.
Data from Foula is particularly useful for assessing the suitability of conditions to deploy pilots on to the oil supertankers prior to berthing at the Sullom Voe terminal.
Hourly observations from the network can be found online.
Produced daily around 0730 UTC.