NASA Scientists see Gravity Waves in Concentric Rings

NASA scientists have tracked gravity waves spreading upward for hundreds of miles and outward for thousands of miles in concentric rings, like ripples in a pond. The waves were created by a large convective storm in 2013 that also spawned a deadly tornado. The visualization shows near-simultaneous measurements of the gravity waves in the troposphere, stratosphere and ionosphere.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite detected gravity waves in the troposphere and stratosphere 12 hours before a deadly EF5 tornado in Moore, Oklahoma. Even stronger waves were detected 11 hours later during AIRS’ next pass. The tornado and waves were produced by a long-lived storm system.

In the ionosphere 250 miles (400 kilometers) above Earth's surface, the gravity waves appear as traveling ionospheric disturbances (TIDs) -- disturbances in the electron content of the region. These were observed in Total Electron Content measurements by ground-based GPS receivers throughout the south central United States. In the visualization, these ionospheric disturbances are shown in greens and yellows.

Gravity waves are formed when a disturbance causes air to be displaced into a region of different air density. There are many common causes for this besides storms -- for example, an air current strikes a mountain and is pushed upward. As gravity waves grow and propagate upward, they play important roles in the upper levels of the atmosphere. In the stratosphere, gravity waves help drive the atmospheric circulation and move ozone from the tropics to the poles.

Observations such as these at multiple heights in the atmosphere provide a unique perspective on how atmospheric layers are linked together. Understanding the spread of gravity waves improves global weather forecasting and space weather forecasting.