Observations of height-dependent pressure-perturbation structure of a strong mesoscale gravity wave

• Published in: Monthly weather review 1992-12, Vol.120 (12), p.2808-2820
• Main Authors: Starr, David O'C., Korb, C. L., Schwemmer, Geary K., Weng, Chi Y.
• Format: Article
• Language: English
• Subjects: Meteorology And Climatology
• ISSN: 0027-0644; 1520-0493
• DOI: 10.1175/1520-0493(1992)120<2808:OOHDPP>2.0.CO;2

Airborne observations using a downward-looking, dual-frequency, near-infrared, differential absorption lidar system provide the first measurements of the height-dependent pressure-perturbation field associated with a strong mesoscale gravity wave. A pressure-perturbation amplitude of 3.5 mb was measured within the lowest 1.6 km of the atmosphere over a 52-km flight line. Corresponding vertical displacements of 250-500 m were inferred from lidar-observed displacement of aerosol layers. Accounting for probable wave orientation, a horizontal wavelength of about 40 km was estimated. Satellite observations reveal wave structure of a comparable scale in concurrent cirrus cloud fields over an extended area. Smaller-scale waves were also observed. Local meteorological soundings are analyzed to confirm the existence of a suitable wave duct. Potential wave-generation mechanisms are examined and discussed. The large pressure-perturbation wave is attributed to rapid amplification or possible wave breaking of a gravity wave as it propagated offshore and interacted with a very stable marine boundary layer capped by a strong shear layer.