4th Symposium on Lidar Atmospheric Applications 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, Ch. Kottmeier and U. Corsmeier Institute for Meteorology and Climate Research, KIT Karlsruhe, Germany 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Questions, which will be addressed Is it possible to visualize and identify different entrainment mechanisms in the atmospheric boundary layer? What is the entrainment zone? Are small-scale boundary layer height fluctuations linked to the current wind field? Is there a correlation between entrainment velocity and entrainment zone thickness? 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Introduction Entrainment Small-scale fluctuations Diurnal increase CBL 1 hour 5 to 22 UTC Kurz was zum Entrainment Schlagwörter – was ist bekannt, wo ist Bedarf? Was haben wir gemacht? Using the 2 µm Doppler lidar an aerosol backscatter as well as vertical wind information are available. We use the CSIP, 2005 data set (gently rolling terrain) 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Boundary layer height (BLH) determination 4 +1 automatically working algorithms for high resolution determination using aerosol backscatter information and vertical velocity variance 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Visualizing entrainment processes Entrainment at the edges of plumes 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Visualizing entrainment processes Entrainment due to large scale engulfment 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Concepts of entrainment zone thickness (EZT) Statistical concepts vs transition zone Kurz was Entrainmentzone ist strongly correlated transition zone is mostly wider all approaches show variations during the day, but no typical diurnal cycle 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Relationship between EZT and BLH Measured ratios corresponds to Δh 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Relationship between EZT and BLH Δh/h 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Correlation vertical wind no simple correlation connecting BLH lifting to updraft and vice versa deformation due to thermals variations reflect processes the air mass experienced upstreams 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Entrainment velocity Δh/h 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Conclusions Results from laboratory studies and simulations were comparable to atmospheric boundary layer measurements It is possible to visualize different entrainment processes using Doppler lidar Statistically concepts and the transition zone concept of the EZT differ but are correlated; mixing, and so entrainment, reaches deeper than varying tops of BLH There is no general relationship between EZT and BLH BLH short-time fluctuations are in principle not linked to the current vertical wind field There is a relationship between entrainment velocity and EZT 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Thanks Thanks for attention. For details please see manuscript. 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Additionally information 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

BLH from aerosol and turbulence profile 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Concepts of EZT Correlation of different statistically concepts (h0,h2 using Percentile analysis and σz standard deviation) Correlation of statistical concepts and transition zone 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

Visualizing entrainment processes 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Entrainment velocity 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Entrainment velocity 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier

K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier Entrainment velocity 4.4 Short time fluctuations of the convective boundary layer height and entrainment observed with Doppler lidar K. Träumner, A. Wieser, C. Kottmeier and U. Corsmeier