NAMMA Cloud Microphysics
Principal Investigator: Andrew Heymsfield, NCAR, heyms1@ucar.edu

This data set consists of data collected from two probes, the Cloud, Aerosol,
and Precipitation Spectrometer (CAPS) and the Precipitation Imaging Probe (PIP),
which are both manufactured by Droplet Measurement Technologies in Boulder, CO.  
The CAPS is a combination of two probes, the Cloud Imaging Probe (CIP) and the 
Cloud and Aerosol Spectrometer (CAS).  

The CIP and PIP are both two-dimensional optical array probes which record
images of particles that travel through their lasers.  The CIP has a resolution
of 25 microns per pixel and the PIP has a resolution of 100 microns per pixel.
The recorded images are then analyzed to produce a particle size distribution 
from 25 microns to 3 centimeters.  The CIP is used for particles smaller than 
1000 microns and the PIP is used for all larger particles.  This data set 
includes the combined particle size distributions and a small sample of images 
from each probe.  

The CAS probe measures particle size distributions from 0.55 to 52.5 microns.
It uses a forward-scattering measurement technique similar to the FSSP.  

Some bulk quantities (ice water content for the 2D probes, liquid water content
for the CAS) are derived from the particle size distributions for the convenience 
of data users.  However, they should be used with caution.  For example, the
liquid water content computation will be invalid in areas of pure ice or aerosol, 
and the ice water content values are not useful in the rain.

Further information on all probes is available at www.dropletmeasurement.com or 
in the following article:

Baumgardner D., H. Jonsson, W. Dawson, D. O’Connor, and R. Newton, 2001: 
The cloud, aerosol and precipitation spectrometer: A new instrument for 
cloud investigations. Atmos. Res., 59-60, 251–264.