A Comparison of Two Sonic Anemometers and Fast-Response Thermometers

Abstract

In an experiment conducted at the Boulder Atmospheric Observatory (BAO), comparisons were made between two types of sonic anemometer and thermometer systems. One sonic anemometer was a single-axis system manufactured by Campbell Scientific, Inc., (SCI) and the other the type routinely used on the BAO tower. It is similar to the sensors manufactured by Applied Technologies, Inc., and AIR Inc. Two identical Campbell Scientific systems were mounted on each side or the BAO System and comparisons made over a range of atmospheric surface layer conditions. The means and standard deviation of the vertical wind component and temperature, along with the temperature flux from each system, showed good agreement. important differences in temperature fluctuation data due to the thermocouple filtering are noted. The effect of these differences on the measured heat fluxes and temperature variances is significant and discussed in some detail. It appears that the response of the CSI thermal mass to solar radiation was the major reason for the discrepancies.