Impact of modified turbulent diffusion of PM<sub>2.5</sub> aerosol in WRF-Chem simulations in eastern China
<p>Correct description of the boundary layer mixing process of particle is an important prerequisite for understanding the formation mechanism of pollutants, especially during heavy pollution episodes. Turbulent vertical mixing determines the distribution of momentum, heat, water vapor and pol...
Guardado en:
| Autores principales: | , |
|---|---|
| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
|
| Materias: | |
| Acceso en línea: | https://doaj.org/article/ee45b78f4dff4f71861388891bf6923f |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| Sumario: | <p>Correct description of the boundary layer mixing process
of particle is an important prerequisite for understanding the formation
mechanism of pollutants, especially during heavy pollution episodes.
Turbulent vertical mixing determines the distribution of momentum, heat,
water vapor and pollutants within the planetary boundary layer (PBL).
However, what is questionable is that the turbulent mixing process of particles
is usually denoted by turbulent diffusion of heat in the
Weather Research and Forecasting model coupled with Chemistry (WRF-Chem).
With mixing-length theory, the turbulent diffusion relationship of particle
is established, embedded into the WRF-Chem and verified based on long-term
simulations from 2013 to 2017. The new turbulent diffusion coefficient is
used to represent the turbulent mixing process of pollutants separately,
without deteriorating the simulation results of meteorological parameters.
The new turbulent diffusion improves the simulation of pollutant
concentration to varying degrees, and the simulated results of PM<span class="inline-formula"><sub>2.5</sub></span>
concentration are improved by 8.3 % (2013), 17 % (2014), 11 % (2015)
and 11.7 % (2017) in eastern China, respectively. Furthermore, the
pollutant concentration is expected to increase due to the reduction of
turbulent diffusion in mountainous areas, but the pollutant concentration
did not change as expected. Therefore, under the influence of complex
topography, the turbulent diffusion process is insensitive to the simulation
of the pollutant concentration. For mountainous areas, the evolution of
pollutants is more susceptible to advection transport because of the
simulation of obvious wind speed gradient and pollutant concentration
gradient. In addition to the PM<span class="inline-formula"><sub>2.5</sub></span> concentration, the concentration of
CO as a primary pollutant has also been improved, which shows that the
turbulent diffusion process is extremely critical for variation of the
various aerosol pollutants. Additional joint research on other processes
(e.g., dry deposition, chemical and emission processes) may be necessary to
promote the development of the model in the future.</p> |
|---|