Table 1.

Instruments with performance notes and references for principle of operation and flight-tested implementations. The two mixing ratios for HDO correspond to the range associated with the type of perturbative experiment under consideration, and with its naturally occurring abundance.

instrument	notes	references
aerosol generator	1 kg of liquid H2SO4 is sufficient to create approximately 3.0×107 m3 (100 m radius by 2 km length cylinder) of 15 μm2 cm−3 surface area density
H2O/HDO injector	10 kg of liquid H2O/HDO is sufficient to generate 10 ppmv enhancement over approximately 3.0×107 m3
aerosol counter	1054 nm scatterometer with 100 size bins can measure 0.06–1 μm particles, 3000 particles s−1	[73,74]
H2O	direct absorption in infrared with Herriot cell: 5% ± 0.2 ppmv accuracy; 2% precision in 1 s	[75]
HDO	mid-infrared integrated cavity output spectroscopy; SNR approximately 105 in 1 s at 10 ppmv, SNR approximately 5 at 1 s and 0.5 ppbv	[76,77]
LIDAR	532 nm micropulse Light Detection and Ranging (LIDAR), integrated to scan mechanism and mounted with clear view for hemispheric scan; range resolution 30/75 m, integration time 1 s	[78,79]
NO2	mid-infrared integrated cavity output spectroscopy; SNR approximately 40 in 1 s at 1 ppbv	[77,80–82]
HCl	mid-infrared integrated cavity output spectroscopy; SNR approximately 40 in 1 s at 1 ppbv	[77,80–82]
BrO	chemical conversion–atomic resonance scattering technique with flight-tested inlet design; SNR approximately 10 at 1 s and 10 pptv	[83,84]
ClO	chemical conversion–atomic resonance scattering technique with flight-tested inlet design; SNR approximately 10 at 1 s and 10 pptv	[83,85–87]
O3	accuracy 2% or better, precision 2% in 10 s