Propagation of Gravity Wave Packets in the Lower Atmosphere Observed by the SOUSY-Svalbard Radar

F.S. Kuo；Jürgen Röttger；H.Y. Lue

Chinese Journal of Physics

41卷4期（2003 / 08 / 01）

309 - 325

英文

The height profiles of the vertical atmospheric motion are analyzed to obtain the vertical phase and group velocities of the atmospheric gravity wave motion. The data were taken during the period between October 22 and October 31 in 2000 using the SOUSY Svalbard Radar. The altitude range of the measurements is between 2.4km and 17.4km. Most of the wave packets in the Range-Time-Intensity (RTI) plots show that the vertical phase and group velocities are in opposite directions (Type 1 wave packets), a typical characteristic of the propagation of atmospheric gravity waves in the linear regime. There are also a significant number of shorter-lasting wave packets showing that the vertical phase and group velocities are in the same direction (Type 2 wave packets). Numerical simulations indicate that a Type 2 wave-packet may be either a result of the Doppler shift effect or created by nonlinear wave-wave interactions. It is shown that the characteristic horizontal wavelength of the linear gravity wave packet can be deduced from the measurement of the vertical components of the phase and group velocities if the horizontal background wind is known.