1. Computers and Weather forecasting WeatherWeather forecasting

2. Menu Weather forecasting Explanation OverviewOverview picture DataData collection Sensors Data logginglogging The Grid SystemSystem WeatherWeather station Radiosonde Satellites Radar WeatherWeather ships Supercomputers Parallel ProcessingProcessing Software Pressing Weather forecasting on any slide will bring you back to this menu

3. During the last two decades the Met Office has used state-of-the-art supercomputers for numerical weather prediction and more recently, also for predictions of global climate. WeatherWeather forecasting This is a picture of a supercomputer

4. WeatherWeather forecasting Weather forecasters are helped by several things. These include:- The computer makes millions of calculations. 1. The computer’s advice 2. Information from radar 3. Information from satellite pictures The sums are called differential equations Before the computer can do the calculations, data has to be collected first.

5. WeatherWeather forecasting Collecting data on the weather is very important. Without the data, the computer could not do the calculations that enable it to make weather predictions. The next slide shows where the data comes from. It also shows where the forecasts are sent. Always remember that the forecasters are highly trained people and they use their judgement and expertise to make their forecast based on the information the computer gives them and the information from the radar and the satellite pictures.

6. Supercomputer Radio-sonde Weather ship and weather buoys Satellites Radar WeatherWeather forecasting Weather stations

7. Forecaster Supercomputer Global forecast services Aviation Shipping National and International Forecast Services up to 7 days ahead. Radio-sonde Weather ship and weather buoys Satellites Radar WeatherWeather forecasting Weather stations

8. Forecaster Supercomputer Global forecast services Aviation Shipping National and International Forecast Services up to 7 days ahead. Radio-sonde Weather ship and weather buoys Satellites Radar WeatherWeather forecasting Weather stations

9. WeatherWeather forecasting Data is collected continuously for the computer from the following:- 1. Weather stations 2. Automated weather stations 3. Satellites 4. Radar 5. Radiosondes 6. Weather ships 7. Mini-radiosondes 8. Radar 9. Aeroplanes 10. Drifting buoys

10. WeatherWeather forecasting The data measurements are made by sensors A sensor is a transducer which responds to some physical property such as pressure, temperature, rate of flow. A transducer is an electronic component which converts energy from one form to another. We want the transducers to send signals to the computer in the Met. Office.

11. 1. Temperature.. Air, surface and subsurface temp. 2. Atmospheric Pressure 3. Wind speed 4. Wind direction 5. Humidity 6. Rainfall WeatherWeather forecasting 7. Sunshine The measurements needed include:-

12. WeatherWeather forecasting These are some of the sensors used to collect data.

13. WeatherWeather forecasting Data logging is the capture and storage of data for future use. All the measurements from the sensors are stored because:- So data logging is used in weather forecasting. The computer processes the data in batches People need to refer back to weather data for many reasons

14. WeatherWeather forecasting The next slides explain more about data collection. To jump to the details of the computers, click on the computer.

15. Mountain effects Formation of clouds Formation of rain and snow Friction Radiation from the earth Radiation from the atmosphere Radiation from the sun Evaporation and heat exchange The atmosphere is split up into a 3-D grid. Each land based grid is about 60km. Sea WeatherWeather forecasting

16. The vertical grid you just saw only had 5 levels. The Met Office uses far more, some computer models work on 40 vertical levels. WeatherWeather forecasting For UK forecasts the horizontal grid is 15km. For the global forecasts the horizontal grid is 60km

17. Sea We need to measure pressure, temperature, wind speed and wind directions as well as rainfall, cloud cover,etc in as many grid spaces as possible WeatherWeather forecasting

18. Sea WeatherWeather forecasting Weather stations are used here.

19. A weather station sends signals back to the Met Office computer. The instruments measure pressure, temperature and humidity. WeatherWeather forecasting Some weather stations are automated. These send their measurements back to the computerdirectly. Picture thanks to Sparholt school who have a great web site www.hants.gov.uk/sparsholtschoolscentre

20. We need to measure pressure, temperature, wind speed and wind directions as well as rainfall, cloud cover,etc Radiosondes are used up here. 20 km Sea WeatherWeather forecasting

21. A radiosonde sends signals back to the Met Office computer. They are attached to a balloon carrying instruments. The instruments measure pressure, temperature and humidity. By measuring the track of the radiosonde, the wind direction and speed can be calculated. WeatherWeather forecasting Photo courtesy of the British Atmospheric Data Centre

22. All over the world, radiosondes are released at midday and midnight UTC. UTC = Universal Time Co-ordinated WeatherWeather forecasting

23. UTC = Universal Time Co-ordinated Hawaii 2 am Atlantic Daylight 9 am Baghdad 3 pm West Australian Standard 7 pm UTC is also known as GMT Greenwich Mean Time Here are some of the times when the radiosondes are released to correspond with the ones in Britain at midday. WeatherWeather forecasting

24. Sea We need to measure pressure, temperature, wind speed and wind directions as well as rainfall, cloud cover,etc Minisondes are used here. 5 km Everest is 8.85 Kms high. So we have shown you a very high mountain! WeatherWeather forecasting

25. A minisonde system takes measurements at 5Km above sea level. Both radiosondes and minisondes use radio waves to transmit the data readings to the computers WeatherWeather forecasting

26. Sea We need to measure pressure, temperature, wind speed and wind directions as well as rainfall, cloud cover,etc Aeroplanes send data too. 10 km WeatherWeather forecasting

27. Sea We need to measure pressure, temperature, wind speed and wind directions as well as rainfall, cloud cover,etc Satellites send data too. 36,000km WeatherWeather forecasting The Geostationary satellites are 36,000 Km above earth.

28. There are two types of satellites. Geostationary. These stay in the same spot. They orbit the earth at exactly the same speed as the earth rotates. They are very high above earth - 36,000 km. 5 geostationary satellites are enough to give global coverage. WeatherWeather forecasting Polar orbiting. These orbit the earth about 14 times a day. They orbit at 1000 km above the earth.

29. WeatherWeather forecasting A Geostationary satellite stays in the same place with respect to earth all the time A Polar orbiting satellite moves above the earth’s surface

30. WeatherWeather forecasting Picture courtesy of the European Organisation for the Exploitation of Meteorological Satellites and photo courtesy of Dundee University. The URL ( Uniform Resource Locator ) www.sat.dundee.ac.uk/tour.html will tell you more about satellites if you are interested Meteosat: a geostationary satellite. It sends microwave signals back to earth. The satellite’s signals are received by antennae. ©Eumetsat 2003

31. This is a Polar Orbiting Satellite WeatherWeather forecasting The satellite can take readings across the entire earth during the course of one day.

32. Sea WeatherWeather forecasting Radar systems are used here. Radar stands for radio detection and ranging. Radio waves are transmitted, when they hit a rain cloud they bounce back to earth and measurements can be taken.

33. WeatherWeather forecasting There is a network of radar systems covering Britain. This is a radar station. The computer and the forecaster receive data from the radar systems. Radar measurements let the forecaster and the computer know if the radar has seen rain clouds.

34. Sea WeatherWeather forecasting There are weather ships out to sea There are also buoys taking weather measurements in the sea

35. This is a Weather ship. WeatherWeather forecasting Buoys are used at sea more than weather ships these days. They send their data automatically back to the computer. Thanks to www.gdfcartophily.co.uk

36. WeatherWeather forecasting The Meteorological Office uses supercomputers. These are the largest computers in the world. There will be a new supercomputer in the Met Office’s new location at Exeter. The Met Office has re-located (moved) to Exeter from Bracknell. Bracknell is near London. Exeter is in the South West of England. Bracknell Exeter

37. WeatherWeather forecasting We store Gigabytes (one thousand million bytes 10 9 ) of data on the Hard drives in our school. Supercomputers have stores for Terabytes of data. A Terabyte is one million, million bytes, 10 12 bytes. A supercomputer is a very large computer, which works very, very fast. It is about 1000 times more powerful than a PC. It also has an enormous store (memory).

38. WeatherWeather forecasting A supercomputer is a very large computer, which works very, very fast. It is about 1000 times more powerful than a PC The Met Office supercomputers are Massively Parallel Processor machines. It usually has many processors working in parallel to achieve the fast processing time.

39. Massively Parallel Processor machines use Parallel processing Parallel processing is the simultaneous use of several processors to perform a single job. A job may be split into a number of tasks each of which may be processed by any available processor. WeatherWeather forecasting

40. WeatherWeather forecasting Parallel processing splits jobs up and gives different processors tasks. These all have to be brought together. When a computer uses several processors in parallel it is known as parallel processing. Parallel processing is difficult to program

41. WeatherWeather forecasting How does parallel processing work?. 287 14 21 1*7 A 2*7 B 4*7 3*7 CD Let’s give four processors A, B, C, D a sum each

42. WeatherWeather forecasting If processor A did all four sums it would take longer. Parallel processing is very complicated to program but it does make it faster to do loads and loads of sums.

43. Massively Parallel Processor machines. MPP systems use a distributed hierarchy of memory. This just means that they have to have a system of accessing the memory available. MPP systems rely on very high bandwidth communications to move data between memory and between different processors so that they are all kept busy during program execution. WeatherWeather forecasting

44. WeatherWeather forecasting Software consists of programs, routines and procedures which can be run on a computer system. There are two types of software, application system

45. Application software is designed to carry out a task (such as keeping accounts, or editing text) which would need to be done even if computers didn’t exist. WeatherWeather forecasting System software is designed to control the operation of a computer. An operating system is an example of systems software. An operating system is the software that controls the overall running of the computer. Operating systems handle the Input/Output operations, interrupts, user requests.

46. The Met Office calls their application software they use for weather forecasting the Unified Model. It is modelling software. WeatherWeather forecasting Application software in Weather Forecasting. The Unified model is run both for climate and operational weather forecasting. It uses a lot of computer time, even on the very latest supercomputers.

47. The computers at the Met Office use an operating system called Unicos/mk. Unicos/mk is an interactive system that can run batch work. It is based on UNIX, a very reliable network operating system. WeatherWeather forecasting Systems software in Weather Forecasting

48. WeatherWeather forecasting The weather forecasts are run in batch mode. Batch mode is when all the jobs or data to be processed are put together for processing and then run together. The batches are done by a piece of software produced by the same company CRAY that makes the computers. It is known as the NQS, the Network Queueing System.

49. WeatherWeather forecasting Copyright Helen ap Derwen Yewlett I would like to thank the Met Office for all their help and for permission to use their photographs throughout this presentation.