Met Office

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The new building on the edge of Exeter

The Met Office (originally an abbreviation for Meteorological Office, but now the official name in itself), which has its headquarters at Exeter in Devon, is the United Kingdom's national weather service.

Established in 1854 as a small department within the Board of Trade under Robert FitzRoy as a service to mariners, the Met Office later became part of the Ministry of Defence. It currently holds a quasi-governmental role, being required to act commercially but also remaining an executive agency of the Ministry of Defence. A little known branch of the Met Office known as the Mobile Met Office accompany forward units in times of conflict advising the armed forces of the prevailing conditions for battle, particularly the RAF. The Hadley Centre for climate change research is also part of the Met Office.

One of the British stalwarts — the Shipping Forecast — is produced by the Met Office and broadcast on BBC Radio 4. The Shipping Forecast has long been of real interest to, and vital to the safety of, Mariners traversing the Sea Areas around the British Isles and its broadcast on radio is still avidly listened to. Less vitally, the Shipping Forecast has been the subject of both books and song lyrics.

In 2003 the Met Office moved its headquarters to Exeter from its previous location of Bracknell in Berkshire and it has a worldwide presence — including a forecasting centre in Aberdeen and offices in Gibraltar and on the Falklands. Other outposts lodge in establishments such as the Joint Centre for Mesoscale Meteorology (JCMM) at Reading University in Berkshire, the Joint Centre for Hydro-Meteorological Research (JCHMR) site at Wallingford in Oxfordshire and there is also a Met Office presence at many Army, Navy and Air Force bases within the UK and abroad.

The Met Office is also one of only two World Area Forecast Centres or WAFCs, and is referred to as WAFC London. The other WAFC is located in Kansas but known as WAFC Washington. WAFC data are used daily to safely and economically route aircraft, particularly on long-haul journeys. The data provide details of wind speed and direction, air temperature, cloud type and tops, and other features of interest to the aviation community, such as volcanic ash eruptions.

The Chief Executive of the Met Office is Mark Hutchinson.

[edit] Air quality forecasts

The Met Office issues air quality forecasts made using NAME, the Met Office's medium-to-long-range atmospheric dispersion model. It was originally developed as a nuclear accident model following the Chernobyl accident in 1986, but has since evolved into an all-purpose dispersion model capable of predicting the transport, transformation and deposition of a wide class of airborne materials. NAME is used operationally by the Met Office as an emergency response model as well as for routine air quality forecasting.

In the air quality forecasts, the level of pollution is described either as an index (ranging from 1 to 10) or as a banding (low, moderate, high or very high). These levels are based on the health effects of each pollutant as shown just below.

Index	Banding	Health Effect
1–3	Low	Effects are unlikely to be noticed even by individuals who know they are sensitive to air pollutants.
4–6	Moderate	Mild effects, unlikely to require action, may be noticed amongst sensitive individuals.
7-9	High	Significant effects may be noticed by sensitive individuals and action to avoid or reduce these effects may be needed (e.g. reducing exposure by spending less time in polluted areas outdoors). Asthmatics will find that their 'reliever' inhaler is likely to reverse the effects on the lung.
10	Very High	The effects on sensitive individuals described for 'High' levels of pollution may worsen.

The forecast is produced for a number of different pollutants and their typical health effects are shown in the following table.

Pollutant	Health Effects at High Level
Nitrogen dioxide Ozone Sulphur dioxide	These gases irritate the airways of the lungs, increasing the symptoms of those suffering from lung diseases.
Particulates	Fine particles can be carried deep into the lungs where they can cause inflammation and a worsening of heart and lung diseases