Fast temperature fluctuation measurements for the determination of CT2 are usually performed by fine wire sensors (resistance wire or thermocouple) or they are based on the virtual temperature measurements of sonic anemometers. The former are mostly used in short time scientific experimental setup, the latter in more long term operational measurement programs. Both assemblies have been working reliably and became more and more user- friendly over the past decades such that accurate and adequate results are often taken as granted. Unfortunately, the instrumental characteristics and configuration of just these devices can have a significant influence on the determined spectra and the derived structure parameters under certain conditions. Especially more or less undocumented device-internal algorithms, unnoticed changes in technical specifications and numerical aspects may lead to unexpected results.
Based on the LITFASS-2009 data and on laboratory investigations, the influence of resolution and accuracy of temperature measurements on the magnitude, the quality and the availability of derived CT2 values shall be illustrated by some typical examples. Based on this, consequences for experimental design and setup, device selection and configuration, analysis algorithms and data interpretation shall be discussed briefly.