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- Author or Editor: F. Einaudi x
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Abstract
A rigorous stability analysis of a saturated atmosphere is carried out and is compared with the parcel method. It is shown that the stability parameter n̄ω 2 (the Brunt-Väisälä frequency) one obtains by the two methods is identical. It is further shown that the replacement of the dry adiabatic by the wet adiabatic lapse rate in studying the stability of a saturated atmosphere is inadequate in certain circumstances. In particular, for an atmosphere at rest with negative temperature gradients, such a replacement may lead to erroneous prediction of instability. Similarly, for an atmosphere with a background wind, the same replacement will lead to underestimation of stability for sufficiently negative temperature gradients.
Abstract
A rigorous stability analysis of a saturated atmosphere is carried out and is compared with the parcel method. It is shown that the stability parameter n̄ω 2 (the Brunt-Väisälä frequency) one obtains by the two methods is identical. It is further shown that the replacement of the dry adiabatic by the wet adiabatic lapse rate in studying the stability of a saturated atmosphere is inadequate in certain circumstances. In particular, for an atmosphere at rest with negative temperature gradients, such a replacement may lead to erroneous prediction of instability. Similarly, for an atmosphere with a background wind, the same replacement will lead to underestimation of stability for sufficiently negative temperature gradients.
Abstract
During the 1978 PHOENIX experiment at the Boulder Atmospheric Observatory in Colorado, the presence of atmospheric gravity waves was detected by various independent remote sensing instruments. Fluctuations in the zenith atmospheric radiation were measured at 22.235 and 55.45 GHz in the water vapor and oxygen absorption bands and compared with corresponding fluctuations of surface pressure and the height of FM-CW radar echo returns. These fluctuations are explained, qualitatively and quantitatively, in terms of an internal gravity wave generated by wind shear above the boundary layer. The analysis shows that the oscillations at 22.235 GHz are essentially due to fluctuations of water vapor in the antenna beam while those at 55.45 GHz are due to temperature variations.
Abstract
During the 1978 PHOENIX experiment at the Boulder Atmospheric Observatory in Colorado, the presence of atmospheric gravity waves was detected by various independent remote sensing instruments. Fluctuations in the zenith atmospheric radiation were measured at 22.235 and 55.45 GHz in the water vapor and oxygen absorption bands and compared with corresponding fluctuations of surface pressure and the height of FM-CW radar echo returns. These fluctuations are explained, qualitatively and quantitatively, in terms of an internal gravity wave generated by wind shear above the boundary layer. The analysis shows that the oscillations at 22.235 GHz are essentially due to fluctuations of water vapor in the antenna beam while those at 55.45 GHz are due to temperature variations.
