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 such as nitric acid, nitric oxide, and bromine chloride in the upper atmosphere. It can also provide measurements of 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 built 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 has a 5 to 50 μm detection range. 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 particle samples are collected on a looped belt where they are exposed to a high-resolution video camera. Particle imagery is recorded at 30 Hz and has an image 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 on UAS. It uses a continuous laser (1370 nm) beam and two mirrors to detect the water vapor concentration around the aircraft. ULH can provide data rates up to 20 Hz, allowing for a spatial resolution of 10 meters or less. It has a detection limit of less than 1 ppmv.

The Cloud Particle Imager (CPI) is an airborne imager developed by SPEC Inc. CPI captures high-resolution (2.3 μm pixel size) images of cloud particles that pass 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 with a refresh rate of 40 Hz. The images from CPI can be used to determine microphysical properties such as particle size and shape.

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 can detect aerosol particles ranging from 0.06 to 2 μm in size and operate at altitudes up to 20 km. Typically, FCAS provides measurements every 10 seconds.

The 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 about 1 to 10 Hz. It can be used for either airborne or laboratory aerosol measurements.

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, along with their optical and physical properties that contain BC. 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 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 the 1.37 μm wavelength 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 a wavelength of 254 nm, enabling it to calculate ozone number density due to 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 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 such as 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 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 the 118.9 nm wavelength and reports data every 35 seconds. It measures ClO and ClONO2 mixing ratios with a precision of 3 pptv and 10 pptv, respectively.

The Nucleation-mode Aerosol Size Spectrometer (NMASS) is an airborne, in situ spectrometer used to measure particle size distribution and cloud condensation nuclei (CCN). NMASS includes five parallel condensation nucleus counters (CNCs) that sample particles within the 3 to 60 nm diameter range. It can be mounted on various types of aircraft and is ideal for sampling cirrus clouds in the upper atmosphere. NMASS delivers 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 with different methods for detecting 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 and 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 water vapor in the atmosphere. DLH operates in the near-infrared range at about 1.4 μm and has a measurement frequency of 100 Hz. It can deliver precise measurements of water vapor 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 can provide measurements with a precision of 0.05 ppmv.

The Fast In-situ Stratospheric Hygrometer (FISH) is an in situ airborne or balloonborne 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) to excite OH molecules, which emit radiation in the 285-330 nm range. The emitted radiation is detected by a photomultiplier tube (PMT), which can be 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.

The Meteorological Measurement System (MMS) is an in situ airborne instrument used to measure atmospheric state parameters. MMS provides high-resolution, accurate measurements of atmospheric pressure, temperature, and wind direction and speed immediately around the plane. 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 Fast Cloud Droplet Probe (FCDP) is an in situ airborne cloud probe manufactured by SPEC Inc. The FCDP measures the concentration and size of cloud droplets by detecting light scattered by particles. It detects particles with diameters ranging from 1.5 to 50 microns and typically records measurements at 1 Hz.

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 allow for the 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 ranging from 25 to 1280 µm.

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 the particles' shape, size, and concentration. HVPS-3 has a pixel resolution of 150 μm and a maximum field of view of 1.92 cm.