Scavenging calculation

Particles are scavenged by cloud droplets in the cloud, and by falling raindrops below the cloud. The change in concentration C is described by the exponential relation C=C0 exp (- λt)
 

\lambda _{icp}=\frac{4.2\times 10^{-7} E_{c}\cdot P}{d_{d}}

In-cloud scavenging

\lambda _{bcp}=\frac{4.2\times 10^{-7} E_{c}\cdot P}{d_{d}}

Below-cloud scavenging

 The in-cloud scavenging coefficient λicp and below-cloud scavenging coefficient λbcp depend on
dd drop diameter
Ec collection efficiency for precipitating cloud droplets
Ep collection efficiency for particles
P precipitation rate in mm/hr (at ground level)
 

Execution 

 
 

The net change of concentration can be calculated straightforwardly when using these parameterizations. However,  the collection efficiencies themselves are a function of droplet size and particle size distribution.

Used in 

 
 


                  Scavenging

        

Read more

Read also
 

Visit the NanoFASE Library for abstracts of deliverable reports.
 

Seinfeld, J. H., & Pandis, S. N. (2016). Atmospheric Chemistry and Physics, Wiley-Inter Science, Chapter 20 pp 856-859.

 

Contact

 

  

Astrid Manders

TNO, Netherlands