Mountain waves seen from space
Nov 19, 1999
Large-scale waves in the atmosphere and stratosphere - generally known as gravity waves and mountain waves - play a large role in the dynamics of various trace gases and can also pose safety hazards to high-altitude aircraft. Although atmospheric physicists have known about these waves for many years, difficulties in obtaining high-altitude experimental data has limited their knowledge of the effect. Now Stephen Eckermann from the Naval Research Laboratory in Washington, DC and Peter Preusse from the University of Wuppertal in Germany have measured stratospheric mountain waves from space.
Eckermann and Preusse analysed data from the cryogenic infrared spectrometer and telescope for the atmosphere (CRISTA), which was flown on the Space Shuttle Atlantis in 1994. They discovered that the gravity waves caused by the flow of air over mountains can exist as high as 45 km, which is well into stratosphere (Science 286 1534). The CRISTA instrument mapped the waves by measuring temperature fluctuations in the stratosphere. The results revealed gravity waves connected to the Andes, the Alps and central Eurasia - some of the largest mountain chains in the world.
"It is exciting that they have found experimental evidence of what we have only previously predicted," said James Denholm-Price, a climate modeller from Kingston University in the UK. The research also has implications for global climate models and weather forecasting.