Mid-latitude Airborne Cirrus Properties Experiment

The NOAA Chemical Ionization Mass Spectrometer (NOAA-CIMS) is an in situ airborne spectrometer developed by NOAA. It was designed to provide high-precision measurements of reactive nitrogen and halogen species, including nitric acid, nitric oxide, and bromine chloride, in the upper atmosphere. It can also measure ozone and water vapor concentrations. NOAA-CIMS has a detection limit of 30 pptv and a temporal resolution of 1 second.

The Small Ice Detector 3 (SID-3) is an in situ airborne particle imager developed by the University of Hertfordshire. It measures high-resolution angular scattering patterns of individual cloud particles to determine particle size distribution and number concentration. It operates at 532 nm and detects particles from 5 to 50 μm. SID-3 provides number concentration measurements typically every 1 second and particle size distribution measurements every 10 seconds.

The Video Ice Particle Sampler (VIPS) is an in situ airborne electro-optical instrument. It continuously collects and images cloud particles as small as 3 μm. Cloud particles are collected on a looped belt and imaged by a high-resolution video camera. Particle imagery is recorded at 30 Hz with a resolution of 1.12 μm per pixel. VIPS also provides particle size distribution and concentration.

The Uncrewed Aerial System (UAS) Laser Hygrometer (ULH) is an in situ airborne hygrometer developed at the Jet Propulsion Laboratory (JPL). It was designed to measure water vapor in the upper troposphere and lower stratosphere from a UAS. It uses a continuous 1370-nm laser beam and two mirrors to detect water vapor concentration around the aircraft. ULH can provide data rates up to 20 Hz, enabling a spatial resolution of 10 meters or less. It has a detection limit of less than 1 ppmv.

The Single Particle Soot Photometer (SP2) is an in situ laser-induced photometer developed by Droplet Measurement Technologies. SP2 measures the black carbon (BC) mass in individual aerosol particles and their optical and physical properties. The device detects aerosol particles with diameters of 200-400 nm and can analyze up to 25,000 particles per second. It operates at a sampling rate of 1 Hz and uses a wavelength of 1.06 μm. It can be used on airborne or ground-based platforms and paired with a Humidified-Dual SP2 (HD-SP2).

The Cloud Particle Imager (CPI) is an airborne imager developed by SPEC Inc. It captures high-resolution (2.3 μm pixel size) images of cloud particles passing through its sampling volume. It uses a charge-coupled device (CCD) camera operating at 810 nm to record images and can capture up to 74 frames per second at a refresh rate of 40 Hz. The images from CPI can be used to determine microphysical properties such as particle size and shape.

The High Volume Precipitation Spectrometer (HVPS) is an in situ airborne particle imager manufactured by SPEC Inc. It uses a 128-photodiode array to capture images of precipitation particles. These images can be used to determine particle shape, size, and concentration. HVPS-3 has a pixel resolution of 150 μm and a maximum field of view of 1.92 cm.

The 2D-Stereo Particle Probe (2D-S) is an in situ airborne optical imaging device developed by SPEC Inc. It uses two diode-laser beams to create stereo images of cloud particles via linear-array shadowing. These images enable determination of cloud particle size distribution, particle number concentration, and ice or liquid water content. 2D-S has a resolution of 10 µm and can measure hydrometeors from 25 to 1280 µm.

The Closed-path Laser Hygrometer (CLH) is an in situ airborne tunable diode laser hygrometer developed by the University of Colorado and the Jet Propulsion Laboratory (JPL). It uses second-harmonic absorption spectroscopy to measure atmospheric water vapor. It operates at 1.37 μm and has a measurement frequency of 0.8 Hz.

The NOAA Dual-Beam UV-Absorption Ozone Photometer (NOAA-O3) is an in situ optical balloon-borne and airborne instrument that measures ozone concentrations in the troposphere and lower stratosphere. It operates at 254 nm, enabling calculation of ozone number density from the precise ozone absorption cross section at that wavelength. It has a sampling rate of 2 Hz and a horizontal resolution of 100 to 200 meters during typical research flights.

The Harvard Halogens Instrument (HAL) is an in situ airborne fluorescence analyzer developed by Harvard University. It uses chemical titration-resonance fluorescence to detect chlorine monoxide (ClO) and thermal dissociation-chemical titration-resonance fluorescence to detect chlorine nitrate (ClONO2). HAL operates at 118.9 nm and reports data every 35 seconds. It measures ClO and ClONO2 mixing ratios with precisions of 3 pptv and 10 pptv, respectively.

The Nucleation-mode Aerosol Size Spectrometer (NMASS) is an airborne, in situ spectrometer that measures particle size distribution and cloud condensation nuclei (CCN). NMASS includes five parallel condensation nucleus counters (CNCs) that sample particles from 3 to 60 nm in diameter. It can be mounted on various aircraft and is ideal for sampling cirrus clouds in the upper atmosphere. NMASS provides rapid measurements with a temporal resolution of 10 Hz.

Harvard Water Vapor (HWV) is an in situ airborne hygrometer developed at Harvard University that measures water vapor mixing ratios in the upper troposphere and lower stratosphere. HWV includes two instruments that use different methods to detect water vapor: the Lyman-α photo-fragment fluorescence instrument (LyA) and a tunable diode laser direct absorption instrument (HHH - Harvard Herriott Hygrometer). By combining both instruments, HWV can identify and reduce systematic errors during flight. It provides measurements of water vapor mixing ratio from 1 to 1000 ppmv at 1 Hz, with an accuracy of 5%.

The Diode Laser Hygrometer (DLH) is an in situ airborne hygrometer developed by NASA’s Langley Research Center (LaRC). It uses tunable diode laser absorption to detect atmospheric water vapor. DLH operates in the near-infrared at about 1.4 μm and has a measurement frequency of 100 Hz. It can deliver precise water vapor measurements even when flying through clouds.

The JPL Laser Hygrometer (JLH) is an in situ airborne hygrometer developed at the Jet Propulsion Laboratory (JPL). It uses a tunable diode laser operating at 1.37 μm to measure atmospheric water vapor in the upper troposphere and lower stratosphere. JLH has a minimum spatial resolution of 25 meters and a detection range of 1 to 500 ppmv. It typically samples at 1 Hz and provides measurements with a precision of 0.05 ppmv.

The Fast Cloud Droplet Probe (FCDP) is an in situ airborne cloud probe manufactured by SPEC Inc. The FCDP measures cloud droplet concentration and size by detecting light scattered by particles. It detects particles with diameters from 1.5 to 50 microns and typically records measurements at 1 Hz.

The Meteorological Measurement System (MMS) is an in situ airborne instrument that measures atmospheric state parameters. MMS provides high-resolution, accurate measurements of atmospheric pressure, temperature, and wind direction and speed immediately around the aircraft. Additional parameters that can be derived include potential temperature, true airspeed, turbulence dissipation rate, and Reynolds number. Measurements of all parameters are typically collected at a rate of 20 Hz.

The Focused Cavity Aerosol Spectrometer (FCAS) is an in situ airborne optical particle counter developed by Particle Measuring Systems, Inc. FCAS detects light scattered by individual aerosol particles to determine their size distribution. It detects aerosol particles from 0.06 to 2 μm and operates at altitudes up to 20 km. Typically, FCAS provides measurements every 10 seconds.

The Airborne Laser Infrared Absorption Spectrometer (ALIAS) is an in situ airborne spectrometer developed by the Jet Propulsion Laboratory. It can also be deployed on balloons. It uses mid-infrared (3.4–8 μm) absorption spectroscopy to measure atmospheric gases, including nitrous oxide (N2O), nitrogen dioxide (NO2), nitric acid (HNO3), hydrochloric acid (HCl), carbon monoxide (CO), and methane (CH4). ALIAS has a vertical resolution of 15 m and a time resolution of 3 seconds or less.

The Fast In-situ Stratospheric Hygrometer (FISH) is an in situ airborne or balloon-borne closed-path hygrometer. It uses the Lyman-alpha photofragment fluorescence technique to measure water vapor in the upper troposphere and lower stratosphere. It consists of a Lyman-alpha radiation source (121.6 nm) that excites OH molecules, which then emit radiation in the 285-330 nm range. The emitted radiation is detected by a photomultiplier tube (PMT), which is used to determine the water vapor mixing ratio. FISH has a measurement frequency of 1 Hz and a detection limit of 0.18-0.13 ppmv.

Particle Analysis by Laser Mass Spectrometry (PALMS) is a laser ionization mass spectrometer operated by NOAA. PALMS provides in situ measurements of aerosol particles and their chemical composition by using a UV laser pulse (193 nm) to generate ions. These ions are then analyzed with a time-of-flight mass spectrometer to produce the mass spectrum of each particle, which can be used to classify individual aerosol particles. PALMS has an aerosol size range of 0.2 to 3 microns and typically collects data at 1 to 10 Hz. It can be used for either airborne or laboratory aerosol measurements.