TAU Cloud Microphysical Code: Method of Moments

Tel Aviv University Geophysics & Planetary Sciences

Cloud Parcel Model Documentation


The code uses the "bin" or "sectional" approach, which means that the drop size distribution is resolved into a number of size bins (in this case 35). It differs from most other microphysical codes in that it solves for two (or more) moments of the drop size distribution in each of the bins. This allows for a more accurate transfer of mass between bins and alleviates anomalous drop growth.

It is based on microphysical routines developed primarily at Tel Aviv University, but also at NOAA, Colorado State University, NCAR and Penn State University. The original components were developed by Tzivion et al. (1987), (1989), Feingold et al. (1988) with later applications and development documented in Reisin et al. (1996), Stevens et al. (1996), Feingold et al. (1999), Tzivion et al. (1999), Yin et al (2000) and Harrington et al. (2000). The main references can be found below. Users are urged to read the earlier references before using the code.

The software is provided "as-is." The code has no express or implied warranties and the authors of the code assume no responsibility or liability for unintended results, or damages stemming from its use.

Processes considered in this code:

  1. Activation of particles from a population of CCN considered to be composed of ammonium sulfate
  2. Growth of drops by condensation
  3. Growth of drops by collision-coalescence
  4. Breakup of drops
  5. Sedimentation

Note: These units are cgs, not MKS.


Tzivion, S., G. Feingold and Z. Levin, An efficient numerical solution to the stochastic coalescence equation, J. Atmos. Sci., 3139-3149, 1987.

Feingold, G., S. Tzivion and Z. Levin, The evolution of raindrop spectra with altitude 1: Solution to the stochastic collection/breakup equation using the method of moments, J. Atmos. Sci., Vol. 45, 3387-3399, 1988.

Tzivion, S., G. Feingold and Z. Levin, The evolution of raindrop spectra. Part II: collisional collection/breakup and evaporation in a rainshaft. J. Atmos. Sci., 46, 3312-3327, 1989.

Reisin, T., Z. Levin and S. Tzivion, Rain production in convective clouds as simulated in as axisymmetric model with detailed microphysics. Part I: Description of the model. J. Atmos. Sci., 53, 479-519, 1996.

Stevens, B., G. Feingold, R. L. Walko and W. R. Cotton, On elements of the microphysical structure of numerically simulated non-precipitating stratocumulus. J. Atmos. Sci., 53, 980-1006, 1996.

Tzivion, S., T. G. Reisin and Z. Levin: A numerical solution of the kinetic collection equation using high spectral grid resolution: A proposed reference. J. Computational Physics, 148, 527-544, 1999.

Reisin, T., Y. Yin, Z. Levin and S. Tzivion: Development of giant drops and high reflectivity cores in Hawaiian clouds: Numerical simulation using a kinematic model with detailed microphysics. Atmos. Res., 45, 275-297, 1998.

Harrington, J. Y., G. Feingold, and W. R. Cotton, Radiative impacts on the growth of a population of drops within simulated summertime Arctic stratus. J. Atmos. Sci., 57, 766-785, 2000.

Yin, Y., Z. Levin, T. G. Reisin and S. Tzivion,: The effects of giant cloud condensation nuclei on the development of precipitation in convective clouds - A numerical study. Atmos. Res., 53, 91-116, 2000.

Tzivion, S. T.G. Reisin and Z. Levin: A new formulation of the spectral multi-moment method for calculating the kinetic collection equation: more accuracy with fewer bins. J. Comp. Phys., 171, 418-422, 2001.

Tzivion, S., T. G. Reisin and Z. Levin: Numerical simulation of a Super Power Energy Tower. J. Fluid Dynamics, Vol. 9, No. 1, 736-749, 2001.

Feingold, G., and S. M. KreidenweisCloud processing of aerosol as modeled by a large eddy simulation with coupled microphysics and aqueous chemistry. J. Geophys. Res., 107, D23, 4687, doi:10.1029/2002JD002054, 2002.

Hill, A., A., S. Dobbie, and Y. Yin, The impact of aerosols on non-precipitating marine stratocumulus. I: Model description and prediction of the indirect effect. Q. J. R. Meteorol. Soc., 134: 1143-1154, 2008.