Turbulent transport dissimilarities of particles, momentum, and heat

The turbulent transport of particles is normally assumed to be similar to the momentum (or heat) transport, both in observations and simulations. However, observations from the boundary layer reinforcement experiment conducted at the Pingyuan County Meteorological Bureau, Shandong Province, China, showed dissimilar turbulent transports for momentum, heat, and particles. Our results reveal the prevalence of ejection and sweep motions in the transport of momentum and heat but not in that of particles. For momentum transport, sweep motion is more efficient, and the contribution of ejection (sweeps) motion is higher during the day (night) for heat transport. Momentum transport may be affected by pollutants during heavy pollution episodes (HPEs), whereas heat transport is affected by pollutants at night during HPEs. The sink/source differences lead to differences in particle transport for different HPEs. Furthermore, the momentum motion does not transport heat and particles in the same manner, particularly during HPEs. Compared to heat and momentum transport, the transport of particles is not significantly affected by stability. The turbulent transport of momentum is often smaller than that of particles and heat. Therefore, certain dissimilarities exist in the turbulent transport of momentum, heat, and particles. Overall, these findings found by the observations shed some light on the turbulent transport of particles in mesoscale models, and the turbulent transport dissimilarities between momentum, heat, and particles have an important impact on correcting and obtaining an accurate particle flux.