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There are several groups all working within the Numerical Weather
Prediction area of the Met Office, all with the ultimate aim of improving
the numerical model that is used to forecast the weather; this in
turn increases the accuracy of the forecasts that are issued. The
model may be improved by better numerical techniques and representation
of the atmosphere, by making better use of existing observations or
by developing new observation types. |
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Numerical modelling is the representation of the atmosphere by a computer
model. By improving the model, more accurate weather forecasts can
be produced. Within this area you may learn more about the numerical
model, how physical processes are represented and how we produce operational
weather forecasts.
More about numerical
modelling |
| How observations are used |
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Observations are crucial to weather forecasting. Many thousand are
received each day and these are processed, quality controlled and
monitored. Within this area you may learn more about different observation
types, the daily coverage and the processing that is performed before
they are used. Another aspect is rerunning forecasts to determine
what effect particular observations had.
More about how
observations are used |
| Data analysis and assimilation |
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After observations have been processed and quality controlled they
then need to be incorporated, or assimilated, into the numerical model.
In doing this very important process, we get a representation of the
current state of the atmosphere, i.e. an analysis, from which a forecast
is obtained.
More about data analysis
and assimilation |
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Perhaps one of the greatest developments in weather forecasting over
the past 40 years has been the development of weather satellites.
A satellite image of current cloud conditions is a familiar sight
on TV weather forecasts but there is far more to satellite data than
simply producing photographs. Here you will learn about the many ways
that satellite data is used from an ever-growing range of instrumentation.
More about satellite
applications
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The observational work is based around two facilities; a group which
operates an aircraft and a group that operates a large range of
surface based instrumentation including a tethered kite balloon.
Both the aircraft and the balloon are heavily equipped with instrumentation
for determining standard meteorological parameters and more specialised
instrumentation for measuring turbulence, cloud, aerosol and radiation.
More about observational
research
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The main modelling tool is based on large eddy simulation (LES)
of flows down to turbulent scales. This relatively high resolution
model is developed for specific problems and validated using observational
data. It then provides a means to develop techniques ("parametrisations")
to enable low resolution models to treat the physics of particular
processes in a realsitic manner.
More about atmospheric
processes and parametrisations
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Typically, a numerical weather prediction model is only run once
from a given set of initial conditions to produce a single forecast.
However, despite the vast improvements in NWP models over the years,
large errors may still occur even over relatively short forecast
ranges. This is due to the chaotic nature of the atmosphere which
means that a small error in the initial conditions may lead to a
large error in the subsequent forecast, the so called 'butterfly
effect'. Because we can never know the exact truth of the initial
conditions, there will always be a degree of uncertainty in the
resulting forecast. To combact this, an ensemble suite of forecasts
may be run with each forecast having slightly different initial
conditions to reflect the uncertainty. The resulting forecasts may
be studied and the possible range of different scenarios evaluated.
This may be used to calculate a probability for a particular forecast
sequence.
More about ensemble
forecasts
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Some of the work performed is in conjunction with other meteorological
services or other research institutions. Occasionally, the Met Office
hosts international conferences or workshops.
More about external
collaboration |
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Much of the work is written up in technical notes and some is published
in various journals. A quarterly newsletter NWP Gazette is
also produced and an annual Scientific and Technical Review
is published alongside the Met Office Annual Report and Accounts.
More about publications
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