Transcript Document

Computers and
Weather forecasting
Weather forecasting
Menu
Explanation
Weather station
Radiosonde
Overview picture
Satellites
Data collection
Radar
Weather ships
Sensors
Data logging
The Grid System
Weather forecasting
Supercomputers
Parallel Processing
Software
Pressing Weather forecasting on any slide
will bring you back to this menu
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.
This is a picture of a supercomputer
Weather forecasting
Weather forecasters are helped by
several things. These include:1. The computer’s advice
2. Information from radar
3. Information from satellite pictures
The computer makes millions of calculations.
The sums are called differential equations
Before the computer can do the calculations,
data has to be collected first.
Weather 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.
Weather forecasting
Satellites
Radio-sonde
Weather
stations
Radar
Weather ship
and weather buoys
Weather forecasting
Supercomputer
Satellites
Radio-sonde
Weather
stations
Radar
Weather ship
and weather buoys
Supercomputer
Aviation
Shipping
Global forecast services
Weather forecasting
Forecaster
National and International
Forecast Services up to
7 days ahead.
Satellites
Radio-sonde
Weather
stations
Radar
Weather ship
and weather buoys
Supercomputer
Aviation
Shipping
Global forecast services
Weather forecasting
Forecaster
National and International
Forecast Services up to
7 days ahead.
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
Weather 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.
Weather forecasting
The measurements needed include:1. Temperature .. Air, surface and subsurface temp.
2. Atmospheric Pressure
3. Wind speed
4. Wind direction
5. Humidity
6. Rainfall
7. Sunshine
Weather forecasting
These are some of the sensors used to collect data.
Weather forecasting
Data logging is the capture and
storage of data for future use.
All the measurements from the sensors are
stored because:• The computer processes the data in batches
• People need to refer back to weather data for
many reasons
So data logging is used in weather forecasting.
Weather forecasting
The next slides explain more about data
collection.
To jump to the details of the computers, click
on the computer.
Weather forecasting
Radiation from the sun
Formation of
rain and
snow
Formation of
clouds
Radiation from
the atmosphere
Mountain
effects
Evaporation and
heat exchange
Radiation from
the earth
Sea
Weather forecasting
Friction
The atmosphere is split up into a 3-D grid.
Each land based grid is about 60km.
The vertical grid you just saw only had 5 levels.
The Met Office uses far more, some computer
models work on 40 vertical levels.
For the global forecasts the horizontal grid is 60km
For UK forecasts the
horizontal grid is 15km.
Weather forecasting
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
Sea
Weather forecasting
Sea
Weather stations are used here.
Weather forecasting
A weather station sends signals back to the Met
Office computer.
The instruments measure
pressure, temperature and
humidity.
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
Weather forecasting
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
her forecasting
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.
Photo courtesy of the British Atmospheric Data Centre
Weather forecasting
UTC =
Universal Time
Co-ordinated
All over the world, radiosondes are released
at midday and midnight UTC.
Weather forecasting
UTC = Universal Time Co-ordinated
Hawaii 2 am
Atlantic
Daylight
9 am
UTC is also known as GMT
Greenwich Mean Time
Baghdad
3 pm
West Australian
Standard 7 pm
Here are some of the times when the radiosondes
are released to correspond with the ones in Britain at midday.
Weather forecasting
We need to measure pressure, temperature,
wind speed and wind directions as well as
rainfall, cloud cover,etc
Minisondes
are used 5 km
here.
Sea
Everest is 8.85 Kms high.
So we have shown you a very high mountain!
Weather forecasting
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
Weather forecasting
We need to measure pressure, temperature,
wind speed and wind directions as well as
rainfall, cloud cover,etc
Aeroplanes
send data
too.
Sea
Weather forecasting
10 km
We need to measure pressure, temperature,
wind speed and wind directions as well as
rainfall, cloud cover,etc
36,000km
Satellites
send data
too.
Sea
Weather forecasting
The Geostationary satellites are
36,000 Km above earth.
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.
• Polar orbiting. These orbit the earth about 14
times a day. They orbit at 1000 km above the
earth.
Weather 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
Weather forecasting
Picture courtesy of the European Organisation
for the Exploitation of Meteorological Satellites
and photo courtesy of Dundee University.
The satellite’s signals are received by
antennae.
©Eumetsat 2003
Meteosat: a
geostationary
satellite. It sends
microwave signals
back to earth.
The URL ( Uniform Resource Locator )
www.sat.dundee.ac.uk/tour.html will tell you
more about satellites if you are interested
Weather forecasting
This is a Polar Orbiting Satellite
The satellite can take readings across the entire
earth during the course of one day.
Weather forecasting
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.
Sea
Radar systems are used here.
Weather forecasting
Radar measurements let the forecaster and the
computer know if the radar has seen rain clouds.
This is a
radar
station.
The computer and the
forecaster receive data from
the radar systems.
Weather forecasting
There is a network of
radar systems
covering Britain.
There are also buoys taking weather
measurements in the sea
Sea
Weather forecasting
There are weather ships out to sea
This is a Weather ship.
Thanks to www.gdfcartophily.co.uk
Buoys are used at sea
more than weather
ships these days.
They send their data
automatically back to
the computer.
Weather forecasting
The Meteorological Office uses supercomputers.
These are the largest computers in the world.
The Met Office has re-located (moved) to Exeter
from Bracknell.
Bracknell is near London.
Exeter is in the South West
of England.
There will be a new
supercomputer
in the Met Office’s new
location at Exeter.
• Bracknell
• Exeter
Weather forecasting
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).
We store Gigabytes (one thousand million bytes 109)
of data on the Hard drives in our school.
Supercomputers have stores for Terabytes of data.
A Terabyte is
one million, million bytes, 1012 bytes.
Weather forecasting
A supercomputer is a very large computer, which
works very, very fast. It is about 1000 times more
powerful than a PC
It usually has many
processors working in
parallel to achieve the
fast processing time.
The Met Office supercomputers are
Massively Parallel Processor machines.
Weather forecasting
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.
Weather forecasting
When a computer uses
several processors in parallel
it is known as
parallel processing.
Parallel processing splits jobs up and gives
different processors tasks. These all have to be
brought together.
Parallel processing is difficult to program
Weather forecasting
How does parallel processing work?
.
A
B
C
D
1*7
2*7
3*7
4*7
Let’s give four processors A, B, C, D a sum each
7
Weather forecasting
14
21
28
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.
Weather forecasting
Massively Parallel Processor machines.
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.
MPP systems use a distributed hierarchy of memory.
This just means that they have to have a system of
accessing the memory available.
Weather forecasting
Software consists of programs, routines and
procedures which can be run on a computer
system.
There are two types of software,
• application
• system
Weather forecasting
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.
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.
Weather forecasting
Application software in Weather Forecasting.
The Met Office calls their application software
they use for weather forecasting the Unified
Model.
It is modelling software.
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.
Weather forecasting
Systems software in Weather Forecasting
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.
Weather 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.
Weather forecasting
I would like to thank the Met Office for
all their help and for permission to use
their photographs throughout this
presentation.
Copyright Helen ap Derwen Yewlett
Weather forecasting