Scintillometry applied to urban studies: evaluation of scintillometer measurements made at a sub-urban site
Jose M. Galvez, University of Oklahoma, Norman, OK; and P. M. Klein and S. Arms
Scintillometry as a tool for measuring turbulent fluxes and dissipation has been explored since the 1970's. The main advantage of scintillometers over alternative turbulence measurement techniques arises from their ability to provide spatially representative quantities. This skill becomes particularly useful when sampling over irregular surfaces, such as urban canopies. A small aperture scintillometer was thus considered, among other instruments, to collect turbulent flux data during the ILREUM Urban Canopy Experiment.
As part of the preparations for this experiment, two short field campaigns were conducted in a sub-urban environment during the summers of 2007 and 2008. These campaigns had the purpose of evaluating the skill of the scintillometer on the measurement of turbulent fluxes and dissipation rates. This was done by comparing the scintillometer data with eddy-covariance measurements from several sonic anemometers. The latter were placed along the laser path to allow for the evaluation of the scintillometer path-averaging algorithm. The findings suggest that scintillometer fluxes are generally in agreement with eddy-covariance measurements. A limitation observed is a reduced sensitivity near neutral conditions, when scintillations are weak. Errors on the calculation of dissipation rates also peak during this period, in particular when inner scale values become lower than ~3.5 mm.
Joint Session 3, Measurements in the Urban Environment—II
Tuesday, 13 January 2009, 3:30 PM-5:30 PM, Room 124A
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