SODAR Calibration for turbulence profiling in TMT site testing
Abstract
As part of the Thirty Meter Telescope (TMT) site testing program, several instruments have been deployed to characterize the turbulence profiles of the candidate sites. To make such measurements in the boundary layer (height < 1,000m) we have installed several SODARs. Initially conceived to make 3-dimensional wind speed profiles, this instrument is also capable of measuring the temperature fluctuation constant CT2. Such a measurement requires calibration to become quantitative. We present in this paper a new calibration method that relies on additional kinetic heat flux measurements. This method is the first method to be fully portable to any other SODARs and does not rely on another turbulence profiler for cross calibration. This method will be used to calibrate all TMT SODAR data.