Boundary-Layer Meteorology

, Volume 95, Issue 3, pp 437–456 | Cite as

Simulated Airborne Flux Measurements in a LES generated Convective Boundary Layer

  • M. Schröter
  • J. Bange
  • S. Raasch


One aim of past boundary-layer experiments with aircraft was the determination of areally averaged heat fluxes. In spite ofsophisticated instrumentation the measured fluxes extrapolated to the ground differed significantly from fluxes measured directly at ground stations. This studypresents simulated sensible heat flux measurements with aircraft flightsthrough a synthetic convective boundary layer created by a401 × 401 × 42 cubic-grid large eddy simulation (LES) with agrid spacing of 50 m. After some considerations with respect to necessary measurement lengths using results ofLenschow and Stankov (1986 – J. Atmos. Sci.43, 1198–1209), simulated measurementcampaigns were carried out in three modelruns. During each model run five sets ofmeasurement runs were carried out successively.During each set of runs 10 aircraftflew at 10 altitudes with a ground speedof 100 m s-1 simultaneously throughtime and space. In total, 150 legs were carried out, 15 at each flight level. The resulting`measured' heat fluxes were compared withthose of the `true' flux profiles obtaineddirectly from the ensemble-averagedLES-generated data. No significant systematic error between `measured' and `true' profiles was observed. Furthermore, the comparison of the resulting relative error with the theory ofLenschow and Stankov showed a good agreement at allmeasurement levels.

Large-eddy simulation Convective boundary layer Spectra Averaging Length Airborne Flux Measurements 


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Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • M. Schröter
    • 1
  • J. Bange
    • 1
  • S. Raasch
    • 1
  1. 1.Institute for Meteorology and ClimatologyUniversity of HannoverGermany

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