Gravity is typically thought of as an invisible force keeping us all inexorably Earthbound. But now a team of researchers from the National Center for Atmospheric Research (NCAR) has found a way to "watch" gravity waves move through the atmosphere towards space.
The Boulder, Colorado-based team, led by NCAR senior scientist Hanli Liu, developed a higher resolution version of the Whole Atmosphere Community Climate Model (WACCM), enabling them to pick up gravity waves at their source, whilst they're still quite small. The researchers then followed the rippling waves on their way into the upper atmosphere, where they dramatically swell and billow.
Liu commented: "We've never seen a global picture of gravity waves in the upper atmosphere before, either from observations or simulations, even though we have suspected their importance up there." He continued, "This is the first time we have been able to capture these waves with a computer model of the whole atmosphere."
Whereas the standard climate model only provides a blurry look at gravitational phenomena in the atmosphere, the latest version -- powered by the NCAR-Wyoming Supercomputing Center's Yellowstone system -- can track waves all the way down to 200km.
The findings, published in the journal *Geophysical Research Letters,*showed how gravity waves grow as they travel upwards. For instance, although the waves created by a tropical cyclone east of Australia started off fairly localised, they reached across the whole of the Pacific Ocean when tracked 100km above the Earth's surface.
Liu said: "For the middle and lower atmosphere, if you miss the gravity wave, you're not missing too much. But it's a different story in the upper atmosphere."
Liu and his colleagues hope the research will help to provide a clearer understanding of how gravity affects behaviour in the atmosphere on a global scale -- and how it can interfere with everything from satellites and GPS readings to radio transmissions.
Although the Sun is often thought to be the cause of these disturbances, a lull in recent solar storm activity has enabled scientists to study the ionosphere in closer detail. As a result, NCAR's new model may soon be able to accurately pinpoint how space weather affects the planet.
This article was originally published by WIRED UK
