Turbulent Fluxes and Thermal Convection in a Valley (SALVE)

1. Turbulent Fluxes and Thermal Convection in a Valley (SALVE) Thomas Foken1, Rafael Eigenmann1 Volkmar Wirth2, Björn Brötz2 Norbert Kalthoff3 (1) Dept. Micrometeorology, University of Bayreuth, (2) Institute for Atmospheric Physics, University of Mainz, (3) University and Research Centre Karlsruhe, Institute for Meteorology and Climate Research

2. The Energy Balance Network during COPS

3. WP1: Eddy covariance measurements • Analysis of Eddy covariance measurements (all sites!) • Footprint and internal boundary layers • Development of a quality code. Data transfer into the data bank Important results for other groups • Analysis with international compared software TK2 • Flux contribution of the relevant surface (in error bars) • Fluxes with error bars and quality code in (formated)

4. Analysis of eddy-covariance measurements (all sites!)

5. WP2: Closure of the surface energy balance • Standard investigation of energy balance closure • Influence of local circulations on energy balance closure • Correction of the energy balance closure Important results for other groups • Energy balance closure analysis for all sites • Energy balance closure correction according to the Bowen ratio • For Fußbach site exact correction with local circulations

6. WP3: Investigation of convection started from the ground • Selection of relevant days for further investigation and LES examples • Investigation of the convective events • Investigation of spectral characteristics for convection

7. Free convection Change of wind direction For the Kinzig valley a circulation system in the valley was found that changes the direction by 180° in the morning and the evening. In a short phase during the transition the wind velocity is nearly zero. Example: Station BT01ETGS (Fußbach), June 19, 2009, IOP 4a In this short phase when the wind velocity is nearly zero the conditions for free convection are given (z/L < -1). These conditions exist for about 30 % of the days (non-synoptical con-vection). Example: Station BT01ETGS (Fußbach), June 19, 2009, IOP 4a

8. Free convection • First results will be presented on: • EGU Vienna, poster session OA 2.1, April, 16 • AMS, Turbulence and Boundary Layer, Stockholm, June 9-13 Change of wind direction For the Kinzig valley a circulation system in the valley was found that changes the direction by 180° in the morning and the evening. In a short phase during the transition the wind velocity is nearly zero. Example: Station BT01ETGS (Fußbach), June 19, 2009, IOP 4a In this short phase when the wind velocity is nearly zero the conditions for free convection are given (z/L < -1). These conditions exist for about 20 % of the days (non-synoptical con-vection). Example: Station BT01ETGS (Fußbach), June 19, 2009, IOP 4a

9. WP3: Investigation of convection started from the ground • Selection of relevant days for further investigation and LES examples • Investigation of the convective events • Investigation of spectral characteristics for convection Important results for other groups • Selection of convective events for all sited (approx. 30% of all days in the valleys) • Dynamics of the generation of convection in the valley with supporting investigations by LES modeling