ABL Dynamics and Chemistry
Human beings, animals and plants are strongly influenced by wind, temperature and moisture conditions in the lower troposphere, the so-called Atmospheric Boundary Layer (ABL). It is also mainly within the ABL that atmospheric constituents such as carbon dioxide or ozone are emitted, dispersed, transported, transformed and deposited. As such, the crucial location of the ABL as a buffer layer between surface/vegetation processes and synoptic atmospheric conditions makes this field of research fundamental to studies of meteorology, atmospheric chemistry, hydrology and plant physiology.
Our investigations focus on understanding the underlying physics of the ABL driven by atmospheric turbulence and its interactions with the land surface and the free troposphere.
Special focus is placed on investigating the nocturnal and diurnal variability of the thermodynamic variables and atmospheric constituents from the surface to the top of the lower troposphere. We base our studies on a complete model hierarchy that ranges from conceptual models and three-dimensional models designed explicitly to solve problems of turbulence (DALES and DNS) to large scale chemistry transport models: see the model hierarchy figure currently develop, maintain and use at MAQ.
The modelling activities are strongly combined and supported by detailed analysis of observations and taking active participation in experimental campaigns (for instance CASES99, DOMINO09).
The knowledge obtained in these research studies is subsequently transferred to applications. The representation of boundary layer processes is included and evaluated in weather forecast (WRF and MM5) and climate models (TM5) in order to improve the physical and chemical descriptions of turbulent mixing, surface exchange and the interaction between the free troposphere and the ABL.
The specific subjects currently being treated at MAQ and related to the atmospheric boundary layer studies include:
- Wind diurnal and nocturnal variability (application to wind energy)
- Evaporation and cloud formation over heterogeneous land surface properties and transitional regimes: clear to cloudy; morning and afternoon transitions (application to weather forecasting, hydrology and climate studies)
- Nocturnal stable boundary-layer processes including fog formation, maintenance and dissipation (application to meteorology and reactant transport)
- Dispersion, transport and transformation of greenhouse gases and reactants (application to atmospheric chemistry and biometeorology)