These factsheets clearly describe and illustrate the processes involved in global weather and climate, providing the most up-to-date answers and information.

1. Clouds

The current classification of clouds is based upon those originated by Luke Howard (1772-1864), a London pharmacist and amateur meteorologist. In 1803 Howard, wrote a book entitled The modifications of clouds and named the various cloud structures he had studied.

2. Thunderstorms

Most thunderstorms are associated with towering clouds known as cumulonimbus. These clouds usually form on warm sunny days or on a cold front, if conditions are right. Moist air near the ground rises as it warms and if cooled sufficiently cumulus clouds form at the condensation level.

3. Water in the atmosphere

When a jug full of iced drink is taken out of the refrigerator, water droplets condense on the outside of the container. This happens because the jug is at a lower temperature than the dew point of the air. 'Dew point' is defined as the temperature at which the air, when cooled, will just become saturated.

4. Climate of the British Isles

The United Kingdom lies in the latitude of predominantly westerly winds where depressions and fronts move bands of cloud and rain eastwards or north-eastwards across the North Atlantic. Between the depressions there are often small mobile anticyclones bringing welcome fair weather.

5. White Christmas

Snow at Christmas is deep-seated in British culture, and many of us long for the likes of the scenes depicted on traditional Christmas cards. The interest in snowy Christmases has its origins in the colder climate of 1550-1850 when Britain was in the grip of the 'Little Ice Age'.

6. The Beaufort scale

It is often said that Francis Beaufort, of the British Royal Navy, was the first to devise a scale of wind force - towards the start of the 19th century. However, in reality he was not the originator of such a scale. A similar one was in use at least a century earlier - and probably long before that.

7. Climate of South West England

The counties included in this area are Cornwall, Devon and Somerset, together with the Isles of Scilly. This factsheet contains a brief description of the landscape and topography and statistics on temperature, sunshine, rainfall, snowfall and wind.

8. The shipping forecast

The Met Office was established as the Meteorological Department of the Board of Trade in 1854 when Captain, later Vice-Admiral, Robert FitzRoy became its first head. FitzRoy introduced the first storm warning service for shipping in 1861.

9. Weather extremes

We can all recall weather we have experienced which seemed extreme or remarkable. The Met Office, and others around the world, keep records of extremes of temperature, sunshine, rainfall, snow, wind and atmospheric pressure. A number are summarised here.

10. Air masses and weather fronts

Air masses are parcels of air that bring distinctive weather features, the air making up an air mass is very uniform in temperature and humidity. Air masses are separated by transition zones or boundaries that may be more sharply defined - these are called fronts.

11. Interpreting weather charts

On a weather chart, lines joining places with equal sea-level pressures are called isobars. Charts showing isobars are useful because they identify features such as anticyclones (areas of high pressure), depressions (areas of low pressure), troughs and ridges which are associated with particular kinds of weather.

12. National Meteorological Archive

In April 1914, at a meeting of the Meteorological Committee, the Met Office, then called The Meteorological Office, accepted responsibility of custodian of appropriate Public Records. To this day the archive remains part of the Met Office.

13. Upper air observations

Knowledge of temperature, humidity and wind at levels well above the ground, form an essential part of the meteorologist's basic data. The state of the upper air can be obtained in many ways, but the main one is by observations from balloon-borne equipment.

14. Microclimates

A microclimate is the distinctive climate of a small-scale area, such as a garden, park, valley or part of a city. The weather variables in a microclimate, such as temperature, rainfall, wind or humidity, may be subtly different to the conditions prevailing over the area as a whole.

15. Weather radar

The word radar is an acronym, from RAdio Detection And Ranging. Although some primitive work on radio location had been carried out in the United Kingdom as early as 1904, it wasn't until the mid 1930s that any serious development work on radar was instigated.

16. World climates

The climate of a locality is the synthesis of the day-to-day values of the meteorological elements that affect the locality. The main climatic elements are precipitation, temperature, humidity, sunshine, wind velocity.

17. Weather observations over land

Meteorological observations are made for a variety of reasons. The aim of all these observations is, essentially, to provide data and are a valuable source of information, which is used in a variety of different ways.

18. Weather satellites

Satellites provide a wealth of observations of the Earth's atmosphere and surface which in principle provide good coverage. Typically more than 105 measurements for a specific satellite observation type are received every day at operational weather centres.

19. Take flight

Flight has always captured the human imagination. Since ancient times people have reflected deeply on the starry heavens above and wondered at the secrets it may hold. It was recognised early on that opening up the skies to flight by human invention would not only create many opportunities for travel and navigation, but also enable closer scientific study of the atmosphere and, in so doing, allow for our assertion of a degree of intellectual control over it.

20. From Sorcery to supercomputers

A brief history of key developments in meteorology as illustrated by Treasures from the National Meteorological Archive collections.

21. History

This shorter history of the Met Office is draws heavily upon the work of the late Malcolm Walker. For more detail on all aspects of the history of the meteorological Office to 2010 we would recommend Walker, M. History of the Meteorological Office, CUP, 2012.



Historical Factsheets

The following factsheets looking at aspects of meteorological history and the history of the Met Office are also available:

Pioneers: British Antarctic Expedition 1910 - 1913

Robert Falcon Scott  and four of his companions died during their return from the South Pole in 1912. In the months prior to the polar trek the men were engaged in a range of scientific research projects. This factsheet highlights Met Office involvement in the expedition.

Remember: The Met Office in World War One and World War Two

The Met Office played an important role in both world wars. This factsheet looks at the work of various parts of the office during both conflicts and includes a section focusing on the pivotal role played by the weather in the run up to D-Day.

All information originating from the Met Office is subject to Crown Copyright and is available under the terms of the Open Government Licence

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