Linear Stability Analysis and Boundary Layer Fluxes of Trace Gases and Aerosols
Abstract
One of the important factors that drive the characteristics of local meteorological phenomena is the vertical transport of turbulent kinetic energy from the earth's surface to higher layers within the troposphere. The instability-induced upward dispersion of turbulence increases the vertical ascension of eddy viscosity and introduces additional Reynold's stresses that affect gradients in the atmosphere, which ultimately controls the heating/cooling rates within different layers. Turbulent kinetic energy can also be introduced within the atmosphere due to vertical shears, which generate vorticity. The relative effects of the buoyancy due to instability and vertical shear are quantified by the Richardson number. Radiosonde data were obtained to extract temperature profiles for various times over a fixed region and used as input to a linear stability analysis. The Boussinesq approximation was also applied where the effects of density between layers was disregarded except for buoyancy. The hydrodynamic linear stability analysis was performed with the appropriate set of boundary conditions. The computed eigenvalues are associated with the amplification rates of normal modes of disturbances embedded in the troposphere, which through momentum exchange encourage instabilities to grow and spread vertically. Distributions of normalized perturbation frequencies associated with disturbances were generated and a frequency-averaged amplification rate was computed for each temperature profile. The average amplification rate was used to quantify the strength of the instability and was correlated with a shape factor used to characterize each temperature profile. The fluxes of chemically and radiatively important trace gases and aerosols were determined from the radiosonde data and correlations were made between the out flowing of these influential atmospheric constituents and the shape factors derived from the vertical temperature profiles.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2006
- Bibcode:
- 2006AGUSMGC33A..03W
- Keywords:
-
- 1616 Climate variability (1635;
- 3305;
- 3309;
- 4215;
- 4513);
- 1635 Oceans (1616;
- 3305;
- 4215;
- 4513);
- 3305 Climate change and variability (1616;
- 1635;
- 3309;
- 4215;
- 4513);
- 3307 Boundary layer processes