Assessing the Webb-Pearman-Leuning Formula in Estimating CO2 Flux at a Tropical Coast

Abstract

The Webb-Pearman-Leuning (WPL) formula is used to minimize the overestimate CO flux by open-path gas analyzer and eddy covariance methods. However, its effectiveness for tropical coastal waters with high air water vapor content requires investigation. This paper assesses the WPL correction on CO flux measurement over the tropical coastal water using three calculation methods: standard (including WPL and other correction methods), raw, and WPL. The results showed that the standard method yielded CO flux of –0.10 µmol m s, which is 60% lower than the raw. The WPL-CO flux (–0.07 µmol m s) is also lower than the raw (–0.25 µmol m s) by 0.17 µmol m s. The WPL formula serves its purpose in minimizing the CO flux overestimation but uses caution with the formula as it can change positive-negative flux signs, especially with temperature and water vapor corrections.