pyrcel.activation.arg2000

pyrcel.activation.arg2000(V, T, P, aerosols=[], accom=1.0, mus=[], sigmas=[], Ns=[], kappas=[], min_smax=False)

Computes droplet activation using a psuedo-analytical scheme.

This method implements the psuedo-analytical scheme of [ARG2000] to calculate droplet activation an an adiabatically ascending parcel. It includes the extension to multiple lognormal modes, and the correction for non-unity condensation coefficient [GHAN2011].

To deal with multiple aerosol modes, the scheme includes an expression trained on the mode std deviations, \(\sigma_i\)

\[S_\text{max} = 1 \bigg/ \sqrt{\sum \frac{1}{S^2_ ext{mi}}\left[H(f_i, g_i)\]

ight]}

This effectively combines the supersaturation maximum for each mode into a single value representing competition between modes. An alternative approach, which assumes the mode which produces the smallest predict Smax sets a first-order control on the activation, is also available

Parameters:

V, T, P : floats

Updraft speed (m/s), parcel temperature (K) and pressure (Pa)

aerosols

: list of AerosolSpecies

List of the aerosol population in the parcel; can be omitted if mus, sigmas, Ns, and kappas are present. If both supplied, will use aerosols.

accom

: float, optional (default=:const:constants.ac)

Condensation/uptake accomodation coefficient

mus, sigmas, Ns, kappas

: lists of floats

Lists of aerosol population parameters; must be present if aerosols is not passed, but aerosols overrides if both are present.

min_smax

: boolean, optional

If True, will use alternative formulation for parameterizing competition described above.

Returns:

smax, N_acts, act_fracs : lists of floats

Maximum parcel supersaturation and the number concentration/activated fractions for each mode

[ARG2000]

Abdul-Razzak, H., and S. J. Ghan (2000), A parameterization of aerosol activation: 2. Multiple aerosol types, J. Geophys. Res., 105(D5), 6837-6844, doi:10.1029/1999JD901161.

[GHAN2011]

Ghan, S. J. et al (2011) Droplet Nucleation: Physically-based Parameterization and Comparative Evaluation, J. Adv. Model. Earth Syst., 3, doi:10.1029/2011MS000074