Atmospheric Tomography Mission

The Chemical Ionization Mass Spectrometer was developed by NOAA. This instrument can take high-precision measurements of gases such as nitric acid, water vapor, and hydrochloric acid. This instrument was designed to take measurements accurately in the boundary layer. The detection limit for CIMS is in the parts-per-trillion range, and the temporal resolution is 50s.

The Laser Aerosol Spectrometer (LAS) is an in situ airborne spectrometer manufactured by TSI, Inc. LAS provides measurements of particle size based on the light scattering of the sampled particles. It operates at 633 nm wavelength and has a particle size range of 0.09 to 7.5 μm. LAS can provide complete particle size distributions at a rate of 10 Hz. LAS is typically used as part of aerosol instrument suites such as NASA’s Langley Aerosol Research Group Experiment (LARGE) and NOAA’s Aerosol Microphysical Properties (AMP).

The HR-AMS is an upgraded version of Aerodyne’s AMS instrument. HR-AMS has a high spatial resolution and a time-of-flight measurement technique. HR-AMS is a mass spectrometer that measures aerosols in the troposphere.

The Georgia Institute of Technology Chemical Ionization Mass Spectrometer (GT-CIMS) is an in situ airborne spectrometer. It uses a lower-pressure flow tube reactor to measure reactive nitrogen species such as nitric acid and peroxyacetyl nitrate (PAN) in the lower atmosphere. GT-CIMS has a typical temporal resolution of 1 second and a detection limit of 10 pptv.

The Trace Organic Gas Analyzer (TOGA) is an in situ airborne analyzer that measures volatile organic compounds (VOCs) in the atmosphere. It uses a combination of fast gas chromatography and mass spectroscopy to provide atmospheric mixing ratios of VOCs. It can detect a wide range of VOCs with high precision (<3%) and accuracy (20% or better) at a time resolution of 40 seconds for a 2-minute cycle.

The Programmable Flask Package (PFP) is a type of whole air sampler. This instrument consists of twelve glass flasks that can be filled with air. The samples collected by the PFP are sent to NOAA’s Global Monitoring Division and INSTAR’s Staple Isotope Lab where they are tested for trace gases. This instrument is used to monitor multiple types of trace gases.

The Picarro gas concentration analyzer is an in situ airborne or ground-based sensor manufactured by Picarro, Inc. It uses Wavelength-Scanned-Cavity Ring Spectroscopy (WS-CRDS) to measure trace gases such as carbon dioxide, carbon monoxide, methane, and water vapor. For carbon dioxide measurements, the laser within Picarro operates at 1603 nm wavelength and 1651 nm wavelength for methane and water vapor measurements. Picarro has a typical sampling time of 2.5 seconds. Depending on the model, Picarro can also provide measurements of carbon isotopes for gas concentrations.

The Quantum Cascade Laser System (QCLS) is an airborne and ground-based in situ spectrometer system designed by Harvard University and Aerodyne Research. QCLS consists of two instruments: the Harvard QCL DUAL instrument and the Harvard QCL CO2 instrument. QCL DUAL uses two thermoelectrically cooled QCL light sources to measure carbon monoxide (CO) at 4.59 microns and methane (CH4) and nitrous oxide (N2O) at 7.87 microns. QCL CO2 instrument uses a single QCL light source to measure carbon dioxide (CO2) concentrations at 4.32 microns. QCLS has a measurement frequency of 1 Hz.

The Cloud Aerosol and Precipitation Spectrometer (CAPS) is an in situ airborne spectrometer manufactured by Droplet Measurement Technologies. It combines the Cloud Imaging Probe (CIP), the Cloud and Aerosol Spectrometer (CAS), and the Hotwire Liquid Water Content (LWC) Sensor into one instrument. CAPS measures the size distribution of aerosol, cloud, and liquid droplets for particles between the sizes of 50-1600 μm at a time resolution of 1 Hz. It can also record images of cloud particles and provide measurements of temperature, pressure, and LWC.

The Soluble Acidic Gases and Aerosols (SAGA) is an in situ airborne sampler owned and operated by the University of New Hampshire. It uses a mist chamber and ion chromatography to collect and analyze select aerosol species. It can provide samples of nitric acid, chloride, sulfates, nitrates, chloride, sodium, potassium, ammonium, and calcium. SAGA has a typical sampling frequency of 5 to 15 minutes and has a detection limit of 1 to 25 pptv depending on the sampled species.

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

The Single Particle Soot Photometer (SP2) is a laser-induced photometer manufactured by Droplet Measurement Technologies. SP2 provides measurements of the black carbon (BC) mass content of individual aerosol particles as well as the optical and physical properties of the particles containing BC. SP2 can be utilized on airborne or ground-based platforms and can be deployed with a paired Humidified-Dual SP2 (HD-SP2). It can detect aerosol particles with a diameter size of 200-400 nm and can measure 25,000 particles/second.

The Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) is an in situ airborne sensor developed by Penn State University. ATHOS uses a laser-induced fluorescence (LIF) technique to measure hydroxide (OH) and hydroperoxyl (HO2) in the atmosphere. ATHOS operates near the 308 nm wavelength, has a pulse repetition frequency of 3 kHz, and has a typical time resolution of 20-30 s. It was designed to be equipped on NASA’s DC-8 aircraft and can collect measurements of OH and HO2 in clear sky and light cloud conditions.

The CalTech Chemical Ionization Mass Spectrometer (CIT-CIMS) is an in situ airborne single mass spectrometer. CIT-CIMS utilizes CF3O-ion chemistry and compact time-of-flight and triple quadrupole spectrometers to measure specific atmospheric trace gases such as nitric acid, hydrogen peroxide, and sulfur dioxide. It was designed with rapid scan capabilities, allowing it to operate at a high temporal resolution (10 Hz) and detect a wide mass range. CIT-CIMS is typically used for airborne observations, but it can be used for ground-based observations as well.

The Whole Air Sampler (WAS) is an airborne in-situ instrument that collects samples of air for analysis of trace gases, such as nonmethane hydrocarbons (NMHCs), Halocarbons, Alkyl Nitrates, and various sulfur compounds that are present in the troposphere. Air samples collected via the WAS then undergo gas chromatography and mass spectrometry to determine which gasses are present in the sample. The WAS collects samples every minute, which enables scientists to get a clear picture of the chemical composition of the environment as research aircraft pass through.

The PAN and Trace Hydrohalocarbon ExpeRiment (PANTHER) is an in situ airborne analyzer. It uses electron capture detection and gas chromatography techniques to measure various trace gases such as methane, peroxyacyl nitrate (PAN), and carbon monoxide. PANTHER has a sampling frequency of 60 to 120 seconds and has an accuracy of around 2% for most species except for PAN (10%). The development of PANTHER was funded through NASA’s Instrument Incubator Program and NOAA’s Climate and Global Change Program.

The Aerosol Microphysical Properties (AMP) is an in situ airborne instrument suite operated by NOAA. It consists of instruments such as the Nucleation-Mode Aerosol Size Spectrometer (NMASS), Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Laser Aerosol Spectrometer (LAS), and Coarse-Mode Aerosol Size Spectrometer (CMASS). AMP provides measurements of aerosol particle size distribution and particle number, size, and volume concentration. It can measure aerosols within the size range of 3 to 40,000 nm and provides measurements at 1 Hz resolution.

The NCAR Airborne Oxygen Instrument (AO2) is an in situ airborne instrument used to measure oxygen (O2) concentrations in the atmosphere. It collects these measurements by using the vacuum-ultraviolet absorption technique. AO2 can also provide measurements of carbon dioxide (CO2) concentrations. At typical flight speeds of 300 knots, AO2 has a corresponding horizontal resolution of 750 m and a vertical resolution of 40 m for 5-second measurements. It has a typical sampling rate of 2.5 seconds.

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 consists of 5 parallel condensation nucleus counters (CNCs) that are used to sample particles within the 3 to 60 nm diameter range. It can be equipped on multiple types of aircraft and is ideal for sampling cirrus clouds in the upper atmosphere. NMASS provides fast time response measurements at a temporal resolution of 10 Hz.

The Charged-couple device (CCD) Actinic Flux Spectroradiometer (CAFS) is an in situ airborne spectroradiometer developed by the Atmospheric Radiation Investigations and Measurements (ARIM) laboratory at NCAR. CAFS measures spectrally resolved ultraviolet and visible actinic flux between 280-650 nm. These measurements can be used to derive the photolysis frequencies for several chemical compounds such as ozone, nitrogen dioxide, formaldehyde, and nitrate. CAFS has a temporal resolution of 1 Hz and a wavelength resolution of about 1.8 nm at 297 nm.

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 measure water vapor in the atmosphere. DLH operates in the near-infrared region at around 1.4 μm and has a measurement frequency of 100 Hz. It can provide accurate measurements of water vapor even while flying through clouds.

The In Situ Airborne Formaldehyde (ISAF) is an airborne optical sensor developed at NASA Goddard Space Flight Center (GSFC). ISAF uses laser induced fluorescence (LIF) to measure formaldehyde throughout the troposphere and lower stratosphere. It operates at the 353 nm wavelength and has a sampling frequency of 1 Hz. ISAF can measure formaldehyde concentrations ranging from 10 pptv to hundreds of ppbv at an accuracy of 10%.

NOx/NOxy is an in situ chemiluminescence instrument. It provides measurements of nitrogen oxides and ozone in the atmosphere at a spatial resolution better than 100m for typical DC-8 research flight speeds. NOx/NOxy can be utilized on ground-based, airborne, and shipborne platforms allowing it to be used in various types of atmospheric chemistry and air quality studies.

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

The Uncrewed Aircraft Systems (UAS) Chromatograph for Atmospheric Trace Species (UCATS) is an in situ airborne instrument suite that measures trace gases in the atmosphere. It consists of three separate instruments: a three-channel gas chromatograph (GC), a dual-beam ozone photometer (OZ), and a tunable diode laser (TDL) spectrometer. The GC measures nitrous oxide (N2O) and sulfur hexafluoride (SF6) every 70 s and measures hydrogen (H2), methane (CH4), and carbon monoxide (CO) every 140 s. The OZ sensor operates at 254 nm and provides ozone measurements every 10 seconds. The TDL spectrometer operates at 1370 nm and provides water vapor measurements every 1 s. UCATS was designed to be operated on UAS, but it has been deployed on piloted aircraft as well.