Supercomputers are used to predict the weather

From VOA Learning English,

this is the Technology Report.

Many Americans start to closely follow weather reports

in the early fall.

During the Atlantic hurricane season,

predicting the strength and movement of

these huge storm systems is of crucial importance.

Thanks to new supercomputers,

meteorologists for the National Oceanic

and Atmospheric Administration (NOAA)

are getting better at predicting the weather

as far as six days out.

Hurricane Sandy hit the East Coast last October,

and caused deaths and widespread damage,

it was one of the costliest storm in U.S. history.

At the time, some people blamed meteorologists

for not correctly predicting the path of the storm.

But weather forecasting is extremely difficult, says Ben Kyger.

He is the Director of Central Operations

at NOAA's National Centers for Environmental Prediction

in College Park, Maryland.

"You’ve got major patterns in the atmosphere,

like the jet stream,

but you’ve also got little eddies, little currents,

little things happening all over the place.

All these little changes are interacting with each other,

continuously, all day long.

So if you look at it from above, from a satellite,

you see the atmosphere moving

and churning in big ways and little ways."

Ben Kyger says oceans are another issue

because they closely interact with the atmosphere

and have a huge effect on storms.

NOAA has spent about $20 million on two new supercomputers,

in an effort to improve the dependability of the forecasts.

"These computers generate the initial model guidance

that the whole forecast process depends on,

for all the weather information that you see,

with snowstorms, tornadoes, hurricanes,

how hot it’s going to be today

— all of your weather forecasts start

with what comes off of these supercomputers."

It takes a huge amount of computational power

to examine data from weather satellites,

ground stations and other sources.

It then take a lot of power to predict temperature,

air pressure, humidity and wind speed.

But human brains and experience

are still very important to the process.

Meteorologists at the National Centers

for Environmental Prediction scan the same data

that the supercomputers get before issuing a weather report.

"They are looking at lots of different models run of different computers,

and then they are creating that five-day forecast.

They use lots of scientific and subjective knowledge

from doing it year after year.

They know where the models are strong, where they’re weak

and they give us significantly better forecasts

than the models would do by themselves."

NOAA issues worldwide forecasts every six hours every day of the year.

The reports are free and are helpful for many countries

that cannot afford their own weather service.

NOAA continues working to improve its weather-forecasting abilities,

another upgrade of its weather-predicting supercomputers

is planed for as earlier as 2015.

And that is the Technology Report from VOA Learning English.

I'm June Simms.