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[weatherman] Over Hagerstown and Martinsburg tomorrow.

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[Narrator] Weather forecasters use them to create

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the nightly weather report. Airline
pilots use them to learn how to fly

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planes experts. Experts use them in virtually every industry and discipline. Their

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computer models. At NASA, scientists use
computer models to enhance our

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understanding of the Earth,
the solar system and the universe. NASA

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satellites orbiting the Earth relay
immense amounts of data back to

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scientists on the ground. Who can then
enter that data into computer model

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simulations. [Rosenzweig] We have then equations and
then we have computer code which solves

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those equations on a day-to-day basis.
[Narrator] NASA is the source for most of the

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research satellite observations of the
atmosphere land and oceans.

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[Webster] So the NASA scientists will look at the
observational data and make theoretical

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projections of what a model might look
like. And they will build a numerical

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model based on the data and then run
that on our computers and then compare

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that to reality. [Narrator] With rapid increases in
computer technology. Models are becoming

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evermore powerful and sophisticated.
Allowing us to simulate our complex

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environment in greater detail. NASA uses
a variety of weather models, such as the

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Goddard Earth observing system model or
GEOS-5. It creates an extraordinarily

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high-resolution realistic looking view
of our atmosphere.

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These Geos-5 simulations showcase
the model's ability to capture fine

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scale cloud features worldwide. Like the
swirling clouds in the Atlantic Ocean

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off the coast of North America. The goal
of weather models is to give the most

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accurate prediction of weather over the
next week to ten days. In 2005 when

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Hurricane Katrina formed over the
Atlantic Ocean, scientists wanted to

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understand the storm. How intense was it? What was its size and structure? And what

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would be its final path. NASA satellites
continuously monitored many aspects of

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the storm from wind speed, rainfall and
sea surface temperature to the storms

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three-dimensional structure. To get a
more complete picture of the storm and

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predict its evolution. Scientists entered
the data into a computer model. Then

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high-powered supercomputers capable of
trillions of calculations per second

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crunched the numbers. This process is
called data assimilation. Data

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assimilation is a two-step cycle that
repeats itself whenever new data becomes

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available. In the first step, the model
runs forward in time to provide an

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estimate of the atmosphere. In the second
step, this estimate gets corrected using

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observations. Then the cycle begins again
each step building upon the last and

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accumulating the information from
satellite and ground observations.

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Weather models are updated every six
hours to include the most current

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observations for the next forecast.
This approach prevents the model from

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straying too far from reality and acts
as a checksum balance system to achieve

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the most accurate forecast.

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While weather models for the conditions
for up to 10 days. Climate models predict

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trends over much longer periods of time.
[Webster] The climate models that are run at the

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NCCS are numerical expressions of the
various processes that make up the

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climate. This includes things like land
surface, movement of water in the ocean

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and movement of air in the atmosphere.
[Narrator] Just as in weather prediction, data

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simulation as a way of bringing all the
observations of the Earth together to

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provide an analysis of our climate. One
example of this technique is MERRA the

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Modern Era Retrospective Analysis for
Research and Application. MERRA

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incorporates data from the entire
satellite record over 30 years of data.

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Its results are data encyclopedia that
can be used for research and analysis.

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MERRA can help meteorologists understand
the variations associated with specific

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weather events in the past. While MERRA
gives us a climate picture across

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decades. The Goddard Institute for Space
Studies or GISS can extend that

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view across centuries. GISS models have
already unraveled average temperature

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trends over 200 years. New GISS simulations
will cover the last 1,000 years to

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verify the models accuracy. They'll also
look forward predicting climate trends

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to the end of the 21st century. With each
satellite launched we gain millions of

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measurements that tell us more about our
planet. Having so much more data will

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require increases in computing power to
synthesize this information into

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meaningful representations of the
climate system as a whole. [Webster] At Goddard

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Space Flight Center we have a tremendous
amount of observational data which is

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captured by our satellites. We have
probably the largest collection of Earth

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Scientists anywhere in the world. And we
have this new state-of-the-art computing

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center. So the combination of the
scientists, the data and the computing

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puts us in a unique position to enable
advances in weather climate research.

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[music]