Nonlinear modulation of O3 and CO induced by mountain waves in the UTLS during TREX
Abstract
We analyse and explain distributions of trace gases, CO and O3, and potential temperature observed in aircraft measurements in the Upper Troposphere and Lower Stratosphere (UTLS) during the Terrain-Induced Rotor Experiment (TREX). These distributions show fluctuations with phases and amplitudes that are modulated and correlations that reverse sign along the horizontal path of the aircraft. It is demonstrated that the observed correlations and distributions of gas traces can be explained by reversible processes induced by interactions between mountain waves with different wavelengths. A wave with a large wave number displaces the air column, causing horizontal variations in the vertical gradients. The small waves evolving in these modulated gradients induce wave-signatures in O3 and CO, with amplitudes and phase relationships that depend on the vertical gradients encountered along the path of the aircraft. This explanation is confirmed by reconstructed tracer variations deduced under this dynamical hypothesis.Keywords
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.A31D0166M
- Keywords:
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- 0341 ATMOSPHERIC COMPOSITION AND STRUCTURE / Middle atmosphere: constituent transport and chemistry