Abstract
Abstract. Coupled balloon-borne observations of Light Optical Aerosol Counter (LOAC), M10 meteorological global positioning system (GPS) sondes, ozonesondes, and GPS radio occultation data, are examined to identify gravity-wave (GW)-induced fluctuations on tracer gases and on the vertical distribution of stratospheric aerosol concentrations during the 2013 ChArMEx (Chemistry-Aerosol Mediterranean Experiment) campaign. Observations reveal signatures of GWs with short vertical wavelengths less than 4 km in dynamical parameters and tracer constituents, which are also correlated with the presence of thin layers of strong local enhancements of aerosol concentrations in the upper troposphere and the lower stratosphere. In particular, this is evident from a case study above Ile du Levant (43.02° N, 6.46° E) on 26–29 July 2013. Observations show a strong activity of dominant mesoscale inertia GWs with horizontal and vertical wavelengths of 370–510 km and 2–3 km respectively, and periods of 10–13 h propagating southward at altitudes of 13–20 km during 27–28 July. The European Centre for Medium-Range Weather Forecasts (ECMWF) analyses also show evidence of mesoscale inertia GWs with similar horizontal characteristics above the eastern part of France. Ray-tracing experiments indicate the jet-front system as the main source of observed GWs. Using a simplified linear GW theory, synthetic vertical profiles of dynamical parameters with large stratospheric vertical wind maximum oscillations of ±40 mms−1 are produced for the dominant mesoscale GW observed at heights of 13–20 km. Parcel advection method reveals signatures of GWs in the ozone mixing ratio and the tropospheric-specific humidity. Simulated vertical wind perturbations of the dominant GWs and small-scale perturbations of aerosol concentration (aerosol size of 0.2–0.7 µm) are revealed to be in phase in the lower stratosphere. Present results support the importance of vertical wind perturbations in the GW–aerosol relationship. Observed mesoscale GWs induce a strong modulation of the amplitude of tracer gases and the stratospheric aerosol background.
Highlights
Gravity waves (GWs) affect the dynamics of the middle atmosphere by momentum transport and momentum deposition, and mixing above the upper troposphere (UT), as well as chemistry and have an impact on the global circulation and climate (Fritts and Alexander, 2003; Geller et al, 2013; Ern et al, 2014)
High-resolution observations of the new balloon-borne Light Optical Aerosol Counter (LOAC) coupled with RS and ozonesonde observations are shown to capture short-scale wave-like structures in the UT and lower stratosphere (LS) during the 2013 Chemistry-Aerosol Mediterranean Experiment (ChArMEx)
A methodology and different complementary tools based on observations and modelling are proposed to describe GWs and to evaluate their effects on tracer constituents and the vertical distribution of aerosol concentration
Summary
Gravity waves (GWs) affect the dynamics of the middle atmosphere by momentum transport and momentum deposition, and mixing above the upper troposphere (UT), as well as chemistry and have an impact on the global circulation and climate (Fritts and Alexander, 2003; Geller et al, 2013; Ern et al, 2014). Analytical wave–tracer interaction models help to identify the nature of waves and to quantify ampli-. F. Chane Ming et al.: Gravity-wave effects on tracer gases and stratospheric aerosol concentrations tudes and effects of waves in the middle atmosphere from observations (Eckermann et al, 1998; Chane Ming et al, 2000; Xu et al, 2000). Chane Ming et al.: Gravity-wave effects on tracer gases and stratospheric aerosol concentrations tudes and effects of waves in the middle atmosphere from observations (Eckermann et al, 1998; Chane Ming et al, 2000; Xu et al, 2000) They are usually used to quantify perturbations induced by GWs on tracer constituents. Measuring constituent response using analytical wave–tracer interaction models remains an inexpensive alternative way to derive correct constituent backgrounds and wave-related quantities
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