The codes are for generating bicontinuous medium for graupel and snowflake, and other given shapes.

@ Guanglin Tang, 2016.08.19, Texas A&M University
[email protected]

Software requirements:

Python
gmsh

Tested for anaconda python/2.7.11 and gmsh/2.9.3-linux

Usage:

1) For graupel generation:
Run
#-----------------------------#
./graupel.py 1.0 0.5 1.2 20 >graupel.txt
#-----------------------------#
where arguments mean:
1.0 ~ C
0.5 ~ a
1.2 ~ lambda
20  ~ Number of points
defined in
Wang, P. K. (1982). Mathematical description of the shape of conical hydrometeors. Journal of the atmospheric sciences, 39(11), 2615-2622.

Then
#-----------------------------#
./randMedium.py graupel.txt 0.2 1 0.5 100 1 >graupel_0.5.dat
#-----------------------------#
where arguments mean:
0.2 ~ tretrahedron size
1   ~ number of separated parts (larger than 1 in case of aggregates)
0.5 ~ density
100 ~ k (inversely proportational to grain size)
1   ~ lp (variance of k)

For detail, see
Xu, X., Tsang, L., & Yueh, S. (2012). Electromagnetic models of co/cross polarization of bicontinuous/DMRT in radar remote sensing of terrestrial snow at X-and Ku-band for CoReH2O and SCLP applications. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 5(3), 1024-1032.

graupel_0.5.dat can be inputed to IGOM code.

In order to convert .dat file to .stl file, run
#-----------------------------#
./dat2stl.py graupel_0.5.dat >graupel_0.5.stl
#-----------------------------#

2) For snowflake generation:
Run
#-----------------------------#
./fractalCrystal.py >snowflake.dat
#-----------------------------#
change beta, a1, a2 and L for your need (See Yang and Liou 1998 Fig 1b(left)).

Then similarly,
#-----------------------------#
./randMedium.py snowflake.dat 0.2 1 0.5 100 1 >graupel_0.5.dat
#-----------------------------#

3) For generation from other shpes (must be in .dat or .msh):
Run
#-----------------------------#
./randMedium.py anyShape.dat 0.2 1 0.5 100 1 >graupel_0.5.dat
or
./randMedium.py anyShape.msh 0.2 1 0.5 100 1 >graupel_0.5.dat
#-----------------------------#