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Updated 21 Nov, 2016 10:33am

US launches next-generation weather satellite with hopes to revolutionise forecasting

At 6:42 on Saturday evening, the United States launched a revolutionary new weather satellite into space from Cape Canaveral, Florida.

When GOES-R arrives at orbit, it will see hurricanes and blizzards with higher resolution than any other US satellite of its kind. The scans will take less time and be transmitted faster. Severe storms will be more predictable through breakthrough lightning mapping.

The weather satellites that silently monitor the atmosphere over North America are approaching the end of their life spans. If they fail, the United States will be left without critical weather data. Scientists at NOAA and Nasa have been warning of this risk for years. In the late 1990s, they began designing instruments for the next generation of satellites.

GOES-R, the first in the new series to launch, will join a large constellation of US satellites that observe our planet’s weather and environment.

It is a game-changer for weather forecasting, but it’s also part of a bigger picture. GOES-R joins an international network of satellites that share data freely among nearly 200 countries. The United States provides data to other nations so they can generate precise forecasts and alert people to prepare for weather events. In turn, those countries share their data with the US National Weather Service.

Advance notice of crippling blizzards, long-range hurricane forecasts is possible because of the freely-provided weather data from Europe, China and Russia. It is a mutual understanding based on an unspoken tenet: Our well-being is important, and so is yours, and we can’t do this without one another.

The notion of sharing weather information dates to the late 1800s, when the knowledge was essential for maritime activity. More than a century later, an unfathomable amount of weather data is shared among 191 governments as members of the World Meteorological Organization, or WMO, an agency of the United Nations. The organisation’s role became crucial after the United States launched the first weather satellite in 1961 and other countries followed suit.

“That’s one of the big things that’s changed in my lifetime,” said Richard Rood, a professor of atmospheric science at the University of Michigan. “The US was originally the only global network, and then the Europeans, Japan and India all started launching their own satellites. We had to develop a data-sharing agreement.”

The international Space Age prompted WMO leaders from the United States and the USSR to create a World Weather Watch programme that allows any country to receive any meteorological data it needs to protect life and property. Global satellite data is critical to that objective. It is the backbone of forecast models, or numerical weather prediction. More than 90 per cent of the data ingested by the models comes from satellites around the world.

“People don’t think about why forecasting has improved,” said Cliff Mass, a professor of meteorology at the University of Washington. “If you look at the revolutions that made forecasting possible, numerical weather prediction is one of them, and satellites were the other.”

They measure how the atmosphere is flowing — its wind speed and direction — based on how clouds move over time. They can see long-wave radiation escaping from the ground and oceans, which is directly related to the temperature and moisture through the depths of the atmosphere. That information, along with “ground-truth” observations from thermometers and weather balloons, is used as a starting point for the forecast. And it can be used to nudge the model back to reality if it gets off-track.

Perhaps the most significant recent example of the satellite network’s role in weather forecasting was Hurricane Sandy in October 2012. After the storm took a disastrous left turn onto the East Coast, researchers at the European Centre for Medium-Range Weather Forecasts sought to determine how critical satellites were to its accurate prediction. Without the information from polar-orbiting satellites, which can observe the entire globe in 24 hours, the forecast “would have given no useful guidance 4-5 days ahead that the storm would make landfall on the New Jersey coast,” the study concluded.

“This goes beyond simply forecasting for the public,” said Rob Masters, the director of external relations for the WMO. “It’s a key source for long-term forecasting and in various sectors of our economy, the environment, health and transportation of all kinds.”

With the addition of GOES-R, the United States will have four satellites parked over the Atlantic and Pacific oceans to monitor weather in North America. But the new generation bears only slight resemblance to the old.

The “camera” instrument on GOES-R — called the Advanced — doubles the resolution of the current NOAA satellites. It can scan the whole hemisphere in five minutes, and if there’s a particularly dangerous weather pattern approaching, forecasters can scan a smaller region over the United States every 30 seconds.

Sudden bursts of lightning could mean thunderstorms are becoming severe. So, GOES-R has a lightning mapper to continuously monitor and transmit all of the lightning strikes across North America and the surrounding oceans.

All of this data will be fed into weather models to improve forecast accuracy. It could extend the lead time of tornado warnings and predict the location of flash flooding before it begins. In other words, it could save more lives not only in the United States, but abroad.

GOES-R is expected to go live in 2017. When it does, it will feed critical, lifesaving data into National Weather Service forecasts. It will also enter a decades-long tradition of international cooperation and humanitarian goodwill.

“This is probably the most complex technology that our species is involved in — weather prediction is,” Mass said. “And we do it together as one species. It’s one of our greatest successes.”

—By arrangement with The Washington Post

Published in Dawn, November 21st, 2016

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