Aerosol particle measurements taken during the airborn ARISTO 2016 campaign.

Several different types of measurements of particle size and concentration
were compared during the 2016 Airborne Research Instrumentation Testing
Opportunity (ARISTO) campaign.  The scanning mobility particle
sizer (SMPS) measured number-size distributions for mobility diameters
between ~20-350 nm or ~8-110 nm, depending on the mobility analyzer
chosen.  Also included were two stand-alone condensation particle
counters (CPC) for determining size-integrated particle
concentrations.  A wing-mounted and a rack-mounted Ultra-High
Sensitivity Aerosol Spectrometer (UHSAS) were used to measure size
distributions between 60 and 1000 nm.  Lastly, two different
sampling inlets were used to investigate performance and observe any
systematic biases.  Most sampling occurred during cloud-free
summer conditions in the western United States.  Number
concentrations from the two CPCs typically agreed within 12% once the
flows in the ultrafine particle counter were corrected as a function of
pressure.  As expected, the size-integrated number concentrations
from the SMPS and UHSAS were generally less than those of the CPCs, as the
former cover only part of the total range of particle sizes measured by
the CPCs.  Integrated number concentrations from the wing-mounted
and rack-mounted UHSAS generally agreed within 20% for all diameter ranges
analyzed.  The overlap region between the SMPS and the UHSAS
showed reasonable agreement of +/- 20%.  Some of the uncertainty
regarding these measurement comparisons originates from a variety of
factors, including sampling frequency, particle refractive index,
differences between physical and mobility diameters, and counting
efficiency uncertainties in the UHSAS optical cavity, especially for the
smallest diameters (60-100 nm).