Prather Research Group

Calculating Kappa from Koehler Theory in R Programming Language

The following script, implemented in the R programming language (http://www.r-project.org/), calculates the hygroscopicity parameter "kappa" for critical supersaturation dry diameter data pairs. This script is modified from Markus Petters’ interactive data language (IDL) script (http://www4.ncsu.edu/~mdpetter/findkappa.pro), which is based on Petters and Kreidenweis (2007), to run on R.

findkappa.r finds the kappa from a dry diameter and critical supersaturation data pair.

Convert your dry diameter and critical supersaturation data pairs into a file called “input.csv” with headers as specified in the findkappa.r script and the columns being time, dry diameter and critical supersaturation.

References:

Petters, M.D and Kreidenweis, S.M., A single parameter representation of hygroscopic growth and cloud condensation nucleus activity, Atmospheric Chemistry and Physics, 7(8), 1961-1971, 2007.



ATOFMS Database Software: The YAADA Toolkit for Matlab

Single particle mass spectrometry datasets can be vast and highly detailed.  Our group uses a toolkit built specially for ATOFMS data by Jonathan O. Allen called YAADA (Yet Another ATOFMS Data Analyzer).  Databases are constructed in a series of data tables, which can be searched independently using unique particle identifiers.  YAADA is open source and is implemented in the Matlab environment. Find more information at www.yaada.org.