The dependence of the β coefficient of REA system with dynamic deadband on atmospheric conditions

We simulated the REA system with dynamic deadband to study numerical value and the effect of atmospheric conditions on the empirical constant β which relates vertical flux to concentration difference between updrafts and downdrafts. We found that the value of β depends only weakly on the friction velocity and atmospheric stability. In agreement with previous studies, the median value obtained for a system with dynamic deadband proportional to 0.5 times the running mean of the standard deviation of vertical wind speed was β = 0.42 ± 0.03. For a single half-hour measurement one has to consider the large uncertainty of ±0.2. According to our study, the dynamic deadband enables the use of a constant value of β in flux calculation.