PartMC  2.6.1
Input File Format: Aerosol Weighting Function

Read an aero_weight from a spec file.

Parameters
[in,out]fileSpec file.
[in,out]aero_weightAerosol weight.

For efficiency the aerosol population can be weighted so that the true number distribution $n(D)$ is given by

\[ n(D) = w(D) c(D) \]

where $w(D)$ is a fixed weighting function, $c(D)$ is the computational (simulated) number distribution, and $D$ is the diameter. Thus a large value of $w(D)$ means that relatively few computational particles are used at diameter $D$, while a small value of $w(D)$ means that relatively many computational particles will be used at that diameter.

The aerosol weighting function is specified by the parameters:

  • weight (string): the type of weighting function — must be one of: "none" for no weighting ( $w(D) = 1$); "power" for a power-law weighting ( $w(D) = D^\alpha$), or "mfa" for the mass flow algorithm weighting ( $w(D) = D^{-3}$ with dependent coagulation particle removal)
  • if the weight is power then the next parameter is:
    • exponent (real, dimensionless): the exponent $\alpha$ in the power law relationship — setting the exponent to 0 is equivalent to no weighting, while setting the exponent negative uses more computational particles at larger diameters and setting the exponent positive uses more computational particles at smaller diameters; in practice exponents between 0 and -3 are most useful

See also: