Raindrop size spectra derived from RICO using TWOPASS, a MATLAB-based analysis program for optical array probe data

In this paper, we will use optical array probe (OAP) data from the recent Rain in Cumulus over the Ocean (RICO) experiment to illustrate features of TWOPASS. TWOPASS is a MATLAB based interactive processing and analysis software package that is designed to increase the accuracy of analyzing OAP data. It combines the best features of automatic analysis with efficient interactive hand editing. The hand editing system is based on a color graphical user interface that provides efficient, random access to any image, and allows the user to interactively obtain all of the image's characteristics. Furthermore, it allows the user the greatest flexibility in designing subsequent applications since the user is no longer required to access the raw OAP data once it has been edited. The software package and its utilities will be demonstrated at the conference. As an example, size spectra obtained in rainshafts emerging from trade wind cumulus clouds will be derived from the processed OAP data, and used to develop a Z-R relationship for clouds observed during RICO.