Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality

Ceilometers are ground-based, remote-sensing sensors that provide measurements of cloud ceilings and vertical visibility. They use either a laser beam or another light source to detect backscatter of clouds, precipitation, and aerosols. Ceilometers can provide detailed and accurate measurements in all types of weather conditions and have low operating costs. Ceilometers are typically used in boundary layer and cloud research applications.

The Pandora Spectrometer System is a ground-based UV-VIS spectrometer used to measure column amounts of trace gases in the atmosphere. It uses total optical absorption spectroscopy for retrievals of ozone, nitrogen dioxide, formaldehyde, and other trace gases. Pandora operates in the 280-525 nm spectral region at a resolution of 0.6 nm. It can make both direct sun and all-sky radiance measurements and has an overall measurement time of 80 seconds. Pandora is a part of a network of identical instruments known as the Pandonia Global Network.

Generic-Atmospheric State (Gen-AtmsState) refers to non-specific instruments on a platform used for measurements of atmospheric state parameters. These are typically in situ sensors that measure temperature, pressure, humidity, and wind speed/direction. Types of atmospheric state instruments include thermometers, hygrometers, barometers, and anemometers.

The NASA Micro-Pulse Lidar Network (MPLNET) is a global ground-based network of Micro-Pulse Lidar (MPL) systems that has been active since 1999. MPLNET provides continuous measurements of aerosol and cloud vertical structure as well as boundary layer height from the surface up to 30 km. The MPL systems operate at a wavelength range of 523-532 nm and have a vertically-resolved spatial resolution of 30 to 75 m depending on the station. Many of the MPLNET sites are co-located with sites in the NASA Aerosol Robotic Network (AERONET) to help reduce errors in retrievals.

Generic-Chemistry Related Sensors (Gen-Chemistry) refers to non-specific instruments on a platform used for atmospheric chemistry measurements. These are typically in situ analyzers that measure various chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratio, composition, particle size, optical properties, and particle size distribution.

The AErosol RObotic NETwork (AERONET) is a federated network of ground-based remote sensing aerosol sensors established by NASA and the PHOtométrie pour le Traitement Opérationnel de Normalisation Satellitaire (PHOTONS) in 1993. Each AERONET site consists of a CIMEL Electronique sunphotometer that provides measurements of sun irradiance and sky radiances. These measurements can be used to retrieve aerosol properties such as aerosol optical depth and extinction. The sunphotometers operate across nine wavelengths (340, 380, 440, 500, 675, 870, 937, 1020, and 1640 nm) and provide aerosol measurements approximately every 15 min. AERONET sites are located across the world, making it possible to map around 90% of the Earth’s surface.

The Nittany Atmospheric Trailer & Integrated Validation Experiment (NATIVE) is a mobile research facility used for satellite validation, air quality monitoring, and pollution transport and deposition. The NATIVE payload includes in situ trace instruments, passive and active remote sensing instruments, and several meteorological probes. It is owned and operated by Pennsylvania State University.

Ozonesondes are in situ balloon-borne instruments used to measure ozone concentration profiles. An ozonesonde consists of an electrochemical ozone sensor connected with a meteorological radiosonde to collect ozone, temperature, pressure, and humidity measurements as it ascends through the atmosphere. It provides ozone profile measurements at a resolution of 100 to 150 m. Ozonesondes have a typical measurement rate of 0.1 Hz and can collect profiles up to around 35 km.

This data will be added in future versions

This description will added in a future version.

The Atmospheric Vertical Observations of CO2 in the Earth’s Troposphere (AVOCET) is an airborne in situ spectrometer developed by NASA’s Langley Research Center (LaRC). AVOCET uses a differential, non-dispersive infrared spectrometer to provide high-resolution measurements of carbon dioxide (CO2). It operates at the 4.26 μm CO2 absorption band and has a measurement frequency of 5 Hz. AVOCET has been deployed in several field investigations since the early 1990s and has participated in over 450 science flights.

Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentration. CPCs measure aerosol concentration by condensing fluid onto the particles, allowing them to grow to more detectable sizes for optical scattering. Typically, CPCs can detect particles with a size range of 7 nm-3 μm, can measure particle concentrations up to 100,000 particles/cc, and can provide measurements at 1-second intervals. CPCs are manufactured by TSI Incorporated and can be deployed on airborne, shipborne, and ground-based platforms.

The Particle Into Liquid Sampler (PILS) is an in situ aerosol sampler manufactured by Brechtel Manufacturing Inc. PILS can be utilized by both ground-based and airborne platforms to collect continuous measurements of ambient aerosol bulk composition. The particles sampled by PILS are mixed with saturated water vapor to produce droplets that are analyzed by either an ion chromatograph (IC) or a total organic carbon detector (TOC). PILS can measure aerosol particles with a size range of 70 nm to 2.5 μm and has a time resolution of 3 min for airborne measurements and 15 min for ground-based.

The Difference Frequency Generation Absorption Spectrometer is an instrument designed to measure formaldehyde in the atmosphere. It measures the gas using an infrared laser. The instrument uses two lasers that operate at 1562nm and 1083nm. The instrument was used in multiple campaigns, and has since been replaced by the Compact Atmospheric Multispecies Spectrometer (CAMS).

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 Thermal-Dissociation Laser Induced Fluorescence (TD-LIF) is an in situ airborne sensor developed at UC Berkeley. It uses a combination of the TD and LIF techniques to measure nitrogen dioxide (NO2), peroxynitrates, nitric acid (HNO3), and other stable organic nitrates in the atmosphere. TD-LIF operates at the 585 nm wavelength and has a typical measurement frequency of 1 Hz.

The Scanning Mobility Particle Sizer (SMPS) is an in situ airborne or ground-based aerosol sensor manufactured by TSI Incorporated. SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles to determine the size distribution. It also measures the number of aerosol particles by using a condensation particle counter (CNC). It can detect particles within the size range of 10-1000 nm and can provide measurements typically around 10 seconds per scan.

LI-COR Gas Analyzer is an in situ gas analyzer manufactured by LI-COR. They can be deployed on aircraft, research vessels, vehicles, balloons, and ground-based platforms. They provide measurements of various trace gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O). Most models use Optical Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to collect measurements. LI-COR gas analyzers have a typical measurement rate of 1 Hz and an operating temperature range of -25 to 45 degrees Celsius.

The Proton Transfer Mass Spectrometer (PTR-MS) is an in situ airborne and ground-based spectrometer designed by the University of Innsbruck in Austria. It measures volatile organic compounds (VOCs) without sample preparation at very low concentrations. PTR-MS uses chemical ionization mass spectroscopy allowing for fast and highly sensitive detection of VOCs. It has a 0.5 to 1 s signal integration time.

The Optical Particle Counter is an instrument based on the principle of light scattering from particles. It is a real time instrument that is typically used to measure particles above 0.05 μm in diameter.

The Differential Absorption Carbon monOxide Measurements (DACOM) is an airborne in situ spectrometer system. It uses the differential absorption technique and an infrared tunable diode laser (TDL) to collect measurements of nitrous oxide (N2O), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) in the atmosphere. DACOM operates across the 4.7, 4.5, and 3.3 μm wavelengths to access the absorption lines for CO, N2O, and CH4. It has a measurement frequency of 5 Hz and a precision of about 1 ppbv.

The Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) is an in situ spectrometer manufactured by Droplet Measurement Technologies. It can be utilized on both airborne and ground-based platforms to measure aerosol size distribution and concentration. UHSAS determines the particle size by detecting the peak light signals of the aerosol particles which are illuminated by a 1054 nm laser. UHSAS can sample particles within the 60 - 1000 nm size range and has a sampling frequency of 10 Hz.

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 Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. APS measures aerodynamic particles in the 0.5-20 μm size range. It also measures the light-scattering intensity of the particles in the 0.37-20 μm optical size range. APS provides particle size distributions for 52 channels at a typical sampling time of 1 second. It uses a laser diode operating at 655 nm and has a size resolution of 0.02 μm at 1 μm. APS can be deployed on aircraft, ships, or ground-based platforms.

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 Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties such as size distribution, number concentration, and scattering and absorption coefficient. LARGE consists of multiple instruments including the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Particle-Into-Liquid Sampler (PILS), Particle Soot Absorption Photometer (PSAP), Cloud and Aerosol Spectrometer (CAS), Cloud Imaging Probe (CIP), and additional cloud and aerosol sensors. The LARGE instruments operate across the 450-700 nm wavelength range, can detect particles in the size range between 0.003-20μm, and have a measurement frequency of 1 Hz. It is typically used for airborne measurements, but it also can be deployed on ground-based platforms such as vehicles.

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 Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It uses Beer's Law to measure the change in light transmission of aerosol particles. These measurements can be used to derive aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a temporal resolution of 1 second. It is typically deployed on aircraft, but it can be deployed on other platforms such as ships and vehicles.

Nephelometers are in situ airborne or ground-based optical sensors. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate across three wavelengths: 450 nm, 550 nm, and 700 nm, and have a typical time resolution of 1 Hz.

This data will be added in future versions.

Generic-Chemistry Related Sensors (Gen-Chemistry) refers to non-specific instruments on a platform used for atmospheric chemistry measurements. These are typically in situ analyzers that measure various chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratio, composition, particle size, optical properties, and particle size distribution.

This data will be added in future versions

The Nittany Atmospheric Trailer & Integrated Validation Experiment (NATIVE) is a mobile research facility used for satellite validation, air quality monitoring, and pollution transport and deposition. The NATIVE payload includes in situ trace instruments, passive and active remote sensing instruments, and several meteorological probes. It is owned and operated by Pennsylvania State University.

The Pandora Spectrometer System is a ground-based UV-VIS spectrometer used to measure column amounts of trace gases in the atmosphere. It uses total optical absorption spectroscopy for retrievals of ozone, nitrogen dioxide, formaldehyde, and other trace gases. Pandora operates in the 280-525 nm spectral region at a resolution of 0.6 nm. It can make both direct sun and all-sky radiance measurements and has an overall measurement time of 80 seconds. Pandora is a part of a network of identical instruments known as the Pandonia Global Network.

Generic-Atmospheric State (Gen-AtmsState) refers to non-specific instruments on a platform used for measurements of atmospheric state parameters. These are typically in situ sensors that measure temperature, pressure, humidity, and wind speed/direction. Types of atmospheric state instruments include thermometers, hygrometers, barometers, and anemometers.

The NASA Micro-Pulse Lidar Network (MPLNET) is a global ground-based network of Micro-Pulse Lidar (MPL) systems that has been active since 1999. MPLNET provides continuous measurements of aerosol and cloud vertical structure as well as boundary layer height from the surface up to 30 km. The MPL systems operate at a wavelength range of 523-532 nm and have a vertically-resolved spatial resolution of 30 to 75 m depending on the station. Many of the MPLNET sites are co-located with sites in the NASA Aerosol Robotic Network (AERONET) to help reduce errors in retrievals.

Generic-Chemistry Related Sensors (Gen-Chemistry) refers to non-specific instruments on a platform used for atmospheric chemistry measurements. These are typically in situ analyzers that measure various chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratio, composition, particle size, optical properties, and particle size distribution.

The AErosol RObotic NETwork (AERONET) is a federated network of ground-based remote sensing aerosol sensors established by NASA and the PHOtométrie pour le Traitement Opérationnel de Normalisation Satellitaire (PHOTONS) in 1993. Each AERONET site consists of a CIMEL Electronique sunphotometer that provides measurements of sun irradiance and sky radiances. These measurements can be used to retrieve aerosol properties such as aerosol optical depth and extinction. The sunphotometers operate across nine wavelengths (340, 380, 440, 500, 675, 870, 937, 1020, and 1640 nm) and provide aerosol measurements approximately every 15 min. AERONET sites are located across the world, making it possible to map around 90% of the Earth’s surface.

The Atmospheric Vertical Observations of CO2 in the Earth’s Troposphere (AVOCET) is an airborne in situ spectrometer developed by NASA’s Langley Research Center (LaRC). AVOCET uses a differential, non-dispersive infrared spectrometer to provide high-resolution measurements of carbon dioxide (CO2). It operates at the 4.26 μm CO2 absorption band and has a measurement frequency of 5 Hz. AVOCET has been deployed in several field investigations since the early 1990s and has participated in over 450 science flights.

Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentration. CPCs measure aerosol concentration by condensing fluid onto the particles, allowing them to grow to more detectable sizes for optical scattering. Typically, CPCs can detect particles with a size range of 7 nm-3 μm, can measure particle concentrations up to 100,000 particles/cc, and can provide measurements at 1-second intervals. CPCs are manufactured by TSI Incorporated and can be deployed on airborne, shipborne, and ground-based platforms.

The Particle Into Liquid Sampler (PILS) is an in situ aerosol sampler manufactured by Brechtel Manufacturing Inc. PILS can be utilized by both ground-based and airborne platforms to collect continuous measurements of ambient aerosol bulk composition. The particles sampled by PILS are mixed with saturated water vapor to produce droplets that are analyzed by either an ion chromatograph (IC) or a total organic carbon detector (TOC). PILS can measure aerosol particles with a size range of 70 nm to 2.5 μm and has a time resolution of 3 min for airborne measurements and 15 min for ground-based.

The Difference Frequency Generation Absorption Spectrometer is an instrument designed to measure formaldehyde in the atmosphere. It measures the gas using an infrared laser. The instrument uses two lasers that operate at 1562nm and 1083nm. The instrument was used in multiple campaigns, and has since been replaced by the Compact Atmospheric Multispecies Spectrometer (CAMS).

The Thermal-Dissociation Laser Induced Fluorescence (TD-LIF) is an in situ airborne sensor developed at UC Berkeley. It uses a combination of the TD and LIF techniques to measure nitrogen dioxide (NO2), peroxynitrates, nitric acid (HNO3), and other stable organic nitrates in the atmosphere. TD-LIF operates at the 585 nm wavelength and has a typical measurement frequency of 1 Hz.

The Scanning Mobility Particle Sizer (SMPS) is an in situ airborne or ground-based aerosol sensor manufactured by TSI Incorporated. SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles to determine the size distribution. It also measures the number of aerosol particles by using a condensation particle counter (CNC). It can detect particles within the size range of 10-1000 nm and can provide measurements typically around 10 seconds per scan.

LI-COR Gas Analyzer is an in situ gas analyzer manufactured by LI-COR. They can be deployed on aircraft, research vessels, vehicles, balloons, and ground-based platforms. They provide measurements of various trace gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O). Most models use Optical Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to collect measurements. LI-COR gas analyzers have a typical measurement rate of 1 Hz and an operating temperature range of -25 to 45 degrees Celsius.

The Proton Transfer Mass Spectrometer (PTR-MS) is an in situ airborne and ground-based spectrometer designed by the University of Innsbruck in Austria. It measures volatile organic compounds (VOCs) without sample preparation at very low concentrations. PTR-MS uses chemical ionization mass spectroscopy allowing for fast and highly sensitive detection of VOCs. It has a 0.5 to 1 s signal integration time.

The Optical Particle Counter is an instrument based on the principle of light scattering from particles. It is a real time instrument that is typically used to measure particles above 0.05 μm in diameter.

The Differential Absorption Carbon monOxide Measurements (DACOM) is an airborne in situ spectrometer system. It uses the differential absorption technique and an infrared tunable diode laser (TDL) to collect measurements of nitrous oxide (N2O), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) in the atmosphere. DACOM operates across the 4.7, 4.5, and 3.3 μm wavelengths to access the absorption lines for CO, N2O, and CH4. It has a measurement frequency of 5 Hz and a precision of about 1 ppbv.

The Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) is an in situ spectrometer manufactured by Droplet Measurement Technologies. It can be utilized on both airborne and ground-based platforms to measure aerosol size distribution and concentration. UHSAS determines the particle size by detecting the peak light signals of the aerosol particles which are illuminated by a 1054 nm laser. UHSAS can sample particles within the 60 - 1000 nm size range and has a sampling frequency of 10 Hz.

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 Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. APS measures aerodynamic particles in the 0.5-20 μm size range. It also measures the light-scattering intensity of the particles in the 0.37-20 μm optical size range. APS provides particle size distributions for 52 channels at a typical sampling time of 1 second. It uses a laser diode operating at 655 nm and has a size resolution of 0.02 μm at 1 μm. APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is optical method for counting atmospheric aerosol particles.

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 Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties such as size distribution, number concentration, and scattering and absorption coefficient. LARGE consists of multiple instruments including the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Particle-Into-Liquid Sampler (PILS), Particle Soot Absorption Photometer (PSAP), Cloud and Aerosol Spectrometer (CAS), Cloud Imaging Probe (CIP), and additional cloud and aerosol sensors. The LARGE instruments operate across the 450-700 nm wavelength range, can detect particles in the size range between 0.003-20μm, and have a measurement frequency of 1 Hz. It is typically used for airborne measurements, but it also can be deployed on ground-based platforms such as vehicles.

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 Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It uses Beer's Law to measure the change in light transmission of aerosol particles. These measurements can be used to derive aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a temporal resolution of 1 second. It is typically deployed on aircraft, but it can be deployed on other platforms such as ships and vehicles.

Nephelometers are in situ airborne or ground-based optical sensors. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate across three wavelengths: 450 nm, 550 nm, and 700 nm, and have a typical time resolution of 1 Hz.

GEOstationary Coastal and Air Pollution Events (GEO-CAPE) Airborne Simulator (GCAS) is an airborne push-broom instrument consisting of two spectrometers. It was developed by the Radiometric Calibration and Flight Development Laboratory at Goddard Space Flight Center (GSFC) as a simulator for the GEO-CAPE mission. The first spectrometer in GCAS operates in the ultraviolet to visible (300-490 nm) range for air quality observations of nitrogen dioxide (NO2), ozone (O3), formaldehyde (HCHO), and other trace gases. The second spectrometer operates in the visible to near-infrared (480-900 nm) to provide measurements of ocean color. GCAS has a typical spatial resolution of 250m across track and 500m along track at an altitude of 9 km and has a frame rate of 12 Hz.

The Airborne Compact Atmospheric Mapper (ACAM) is a remote-sensing airborne spectrometer designed at NASA's Goddard Space Flight Center (GSFC). It utilizes two thermally stabilized spectrometers to collect measurements of nitrogen dioxide, sulfur dioxide, ozone, formaldehyde, and aerosols in the ultraviolet, visible, and near-infrared spectral range (310-900 nm). ACAM typically operates at a spatial resolution of 30 m and a temporal resolution of 10 Hz. Measurements from ACAM can be used for calibration and validation of observations from the Aura satellite.

The Second Generation High Spectral Resolution Lidar (HSRL-2) is an airborne lidar developed by the NASA Langley Research Center. HSRL-2 measures aerosol backscatter at the 355, 532, and 1064 nm wavelengths and aerosol extinction at the 355 and 532 nm wavelengths. It has a horizontal resolution of 1-2 km and a vertical resolution of 15 m, and it takes measurements roughly every 0.5 seconds. It replaced the High Spectral Resolution Lidar (HSRL).

The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) is an airborne pushbroom spectrometer developed by Ball Aerospace through support by NASA’s Earth Science Technology Office. GeoTASO measures nadir backscattered solar radiation in the ultraviolet (290-400 nm) and visible (415-695 nm) wavelengths. These measurements can be used to determine aerosols and trace gases in the atmosphere such as ozone, formaldehyde, and nitrogen dioxide. GeoTASO has a spatial resolution of about 250 m x 250 m and has an integration time of 0.25 s.

The Atmospheric Vertical Observations of CO2 in the Earth’s Troposphere (AVOCET) is an airborne in situ spectrometer developed by NASA’s Langley Research Center (LaRC). AVOCET uses a differential, non-dispersive infrared spectrometer to provide high-resolution measurements of carbon dioxide (CO2). It operates at the 4.26 μm CO2 absorption band and has a measurement frequency of 5 Hz. AVOCET has been deployed in several field investigations since the early 1990s and has participated in over 450 science flights.

The Polarized Imaging Nephelometer (PI-Neph) is an in situ airborne nephelometer designed and built at the Laboratory of Aerosols, Clouds and Optics (LACO) at the University of Maryland Baltimore County (UMBC). PI-Neph measures the ambient scattering coefficient and phase matrix of aerosols to validate satellite observations of aerosols. It measures simultaneously across the 473 nm, 532 nm, and 671 nm wavelengths and at a scattering angle range of 2 to 178 degrees. PI-Neph has a typical measurement frequency of 12 or 36 seconds.

Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentration. CPCs measure aerosol concentration by condensing fluid onto the particles, allowing them to grow to more detectable sizes for optical scattering. Typically, CPCs can detect particles with a size range of 7 nm-3 μm, can measure particle concentrations up to 100,000 particles/cc, and can provide measurements at 1-second intervals. CPCs are manufactured by TSI Incorporated and can be deployed on airborne, shipborne, and ground-based platforms.

The Particle Into Liquid Sampler (PILS) is an in situ aerosol sampler manufactured by Brechtel Manufacturing Inc. PILS can be utilized by both ground-based and airborne platforms to collect continuous measurements of ambient aerosol bulk composition. The particles sampled by PILS are mixed with saturated water vapor to produce droplets that are analyzed by either an ion chromatograph (IC) or a total organic carbon detector (TOC). PILS can measure aerosol particles with a size range of 70 nm to 2.5 μm and has a time resolution of 3 min for airborne measurements and 15 min for ground-based.

The Difference Frequency Generation Absorption Spectrometer is an instrument designed to measure formaldehyde in the atmosphere. It measures the gas using an infrared laser. The instrument uses two lasers that operate at 1562nm and 1083nm. The instrument was used in multiple campaigns, and has since been replaced by the Compact Atmospheric Multispecies Spectrometer (CAMS).

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 Thermal-Dissociation Laser Induced Fluorescence (TD-LIF) is an in situ airborne sensor developed at UC Berkeley. It uses a combination of the TD and LIF techniques to measure nitrogen dioxide (NO2), peroxynitrates, nitric acid (HNO3), and other stable organic nitrates in the atmosphere. TD-LIF operates at the 585 nm wavelength and has a typical measurement frequency of 1 Hz.

The Scanning Mobility Particle Sizer (SMPS) is an in situ airborne or ground-based aerosol sensor manufactured by TSI Incorporated. SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles to determine the size distribution. It also measures the number of aerosol particles by using a condensation particle counter (CNC). It can detect particles within the size range of 10-1000 nm and can provide measurements typically around 10 seconds per scan.

LI-COR Gas Analyzer is an in situ gas analyzer manufactured by LI-COR. They can be deployed on aircraft, research vessels, vehicles, balloons, and ground-based platforms. They provide measurements of various trace gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O). Most models use Optical Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to collect measurements. LI-COR gas analyzers have a typical measurement rate of 1 Hz and an operating temperature range of -25 to 45 degrees Celsius.

The Proton Transfer Mass Spectrometer (PTR-MS) is an in situ airborne and ground-based spectrometer designed by the University of Innsbruck in Austria. It measures volatile organic compounds (VOCs) without sample preparation at very low concentrations. PTR-MS uses chemical ionization mass spectroscopy allowing for fast and highly sensitive detection of VOCs. It has a 0.5 to 1 s signal integration time.

The Optical Particle Counter is an instrument based on the principle of light scattering from particles. It is a real time instrument that is typically used to measure particles above 0.05 μm in diameter.

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 Differential Absorption Carbon monOxide Measurements (DACOM) is an airborne in situ spectrometer system. It uses the differential absorption technique and an infrared tunable diode laser (TDL) to collect measurements of nitrous oxide (N2O), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) in the atmosphere. DACOM operates across the 4.7, 4.5, and 3.3 μm wavelengths to access the absorption lines for CO, N2O, and CH4. It has a measurement frequency of 5 Hz and a precision of about 1 ppbv.

The Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) is an in situ spectrometer manufactured by Droplet Measurement Technologies. It can be utilized on both airborne and ground-based platforms to measure aerosol size distribution and concentration. UHSAS determines the particle size by detecting the peak light signals of the aerosol particles which are illuminated by a 1054 nm laser. UHSAS can sample particles within the 60 - 1000 nm size range and has a sampling frequency of 10 Hz.

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 Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. APS measures aerodynamic particles in the 0.5-20 μm size range. It also measures the light-scattering intensity of the particles in the 0.37-20 μm optical size range. APS provides particle size distributions for 52 channels at a typical sampling time of 1 second. It uses a laser diode operating at 655 nm and has a size resolution of 0.02 μm at 1 μm. APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is optical method for counting atmospheric aerosol particles.

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 Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties such as size distribution, number concentration, and scattering and absorption coefficient. LARGE consists of multiple instruments including the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Particle-Into-Liquid Sampler (PILS), Particle Soot Absorption Photometer (PSAP), Cloud and Aerosol Spectrometer (CAS), Cloud Imaging Probe (CIP), and additional cloud and aerosol sensors. The LARGE instruments operate across the 450-700 nm wavelength range, can detect particles in the size range between 0.003-20μm, and have a measurement frequency of 1 Hz. It is typically used for airborne measurements, but it also can be deployed on ground-based platforms such as vehicles.

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 Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It uses Beer's Law to measure the change in light transmission of aerosol particles. These measurements can be used to derive aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a temporal resolution of 1 second. It is typically deployed on aircraft, but it can be deployed on other platforms such as ships and vehicles.

Nephelometers are in situ airborne or ground-based optical sensors. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate across three wavelengths: 450 nm, 550 nm, and 700 nm, and have a typical time resolution of 1 Hz.

GEOstationary Coastal and Air Pollution Events (GEO-CAPE) Airborne Simulator (GCAS) is an airborne push-broom instrument consisting of two spectrometers. It was developed by the Radiometric Calibration and Flight Development Laboratory at Goddard Space Flight Center (GSFC) as a simulator for the GEO-CAPE mission. The first spectrometer in GCAS operates in the ultraviolet to visible (300-490 nm) range for air quality observations of nitrogen dioxide (NO2), ozone (O3), formaldehyde (HCHO), and other trace gases. The second spectrometer operates in the visible to near-infrared (480-900 nm) to provide measurements of ocean color. GCAS has a typical spatial resolution of 250m across track and 500m along track at an altitude of 9 km and has a frame rate of 12 Hz.

The Airborne Compact Atmospheric Mapper (ACAM) is a remote-sensing airborne spectrometer designed at NASA's Goddard Space Flight Center (GSFC). It utilizes two thermally stabilized spectrometers to collect measurements of nitrogen dioxide, sulfur dioxide, ozone, formaldehyde, and aerosols in the ultraviolet, visible, and near-infrared spectral range (310-900 nm). ACAM typically operates at a spatial resolution of 30 m and a temporal resolution of 10 Hz. Measurements from ACAM can be used for calibration and validation of observations from the Aura satellite.

The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) is an airborne pushbroom spectrometer developed by Ball Aerospace through support by NASA’s Earth Science Technology Office. GeoTASO measures nadir backscattered solar radiation in the ultraviolet (290-400 nm) and visible (415-695 nm) wavelengths. These measurements can be used to determine aerosols and trace gases in the atmosphere such as ozone, formaldehyde, and nitrogen dioxide. GeoTASO has a spatial resolution of about 250 m x 250 m and has an integration time of 0.25 s.

The Second Generation High Spectral Resolution Lidar (HSRL-2) is an airborne lidar developed by the NASA Langley Research Center. HSRL-2 measures aerosol backscatter at the 355, 532, and 1064 nm wavelengths and aerosol extinction at the 355 and 532 nm wavelengths. It has a horizontal resolution of 1-2 km and a vertical resolution of 15 m, and it takes measurements roughly every 0.5 seconds. It replaced the High Spectral Resolution Lidar (HSRL).

The Langley Mobile Ozone Lidar (LMOL) is an active remote sensor that utilizes a laser to measure atmospheric ozone and aerosols. LMOL is housed in a trailer so that it is easily transferred to different locations. The laser has a 287 nm and a 292 nm wavelength for ozone retrievals and a 527 nm wavelength for other aerosol retrievals. In addition, it has a 70 ns pulse width and a 7.5 m range resolution. LMOL is part of the Tropospheric Ozone Lidar Network (TOLNet), which is operated by NASA.

The NASA Goddard Tropospheric Ozone Lidar (TROPOZ) is a mobile, ground-based lidar that is part of the Tropospheric Ozone Lidar Network (TOLNet). It uses the differential absorption lidar (DIAL) technique to measure ozone at 289 nm and 299 nm. TROPOZ has a range resolution of 15 m, a repetition rate of 50 Hz, and can generate ozone profiles from 0.35 to 16 km above ground level.

The Nittany Atmospheric Trailer & Integrated Validation Experiment (NATIVE) is a mobile research facility used for satellite validation, air quality monitoring, and pollution transport and deposition. The NATIVE payload includes in situ trace instruments, passive and active remote sensing instruments, and several meteorological probes. It is owned and operated by Pennsylvania State University.

The Tropospheric Ozone Lidar Network (TOLNet) is an interagency initiative among NASA, NOAA, and USEPA starting in 2011. TOLNet provides highly time-resolved measurements of tropospheric ozone profiles that support air quality research and satellite validation. TOLNet consists of six different sensors across the United States: Jet Propulsion Laboratory’s Table Mountain tropospheric Ozone DIfferential Absorption Lidar (JPL-TMO DIAL), NOAA’s Earth System Research Laboratory Tunable Optical Profiler for Aerosol and oZone (TOPAZ), University of Alabama in Huntsville’s Rocket-city Ozone Quality Evaluation in the Troposphere (RO3QET), Goddard Space Flight Center’s TROPospheric OZone-DIfferential Absorption Lidar (TROPOZ DIAL), Langley Research Center’s Langley Mobile Ozone Lidar (LMOL), and Environment and Climate Change Canada’s Autonomous Mobile Ozone LIDAR Instrument for Tropospheric Experiments (AMOLITE). The mobile systems within TOLNet can be deployed in the field to provide collocated measurements of ozone with balloon and airborne sensors.

Ceilometers are ground-based, remote-sensing sensors that provide measurements of cloud ceilings and vertical visibility. They use either a laser beam or another light source to detect backscatter of clouds, precipitation, and aerosols. Ceilometers can provide detailed and accurate measurements in all types of weather conditions and have low operating costs. Ceilometers are typically used in boundary layer and cloud research applications.

The NASA Goddard Tropospheric Ozone Lidar (TROPOZ) is a mobile, ground-based lidar that is part of the Tropospheric Ozone Lidar Network (TOLNet). It uses the differential absorption lidar (DIAL) technique to measure ozone at 289 nm and 299 nm. TROPOZ has a range resolution of 15 m, a repetition rate of 50 Hz, and can generate ozone profiles from 0.35 to 16 km above ground level.

The Pandora Spectrometer System is a ground-based UV-VIS spectrometer used to measure column amounts of trace gases in the atmosphere. It uses total optical absorption spectroscopy for retrievals of ozone, nitrogen dioxide, formaldehyde, and other trace gases. Pandora operates in the 280-525 nm spectral region at a resolution of 0.6 nm. It can make both direct sun and all-sky radiance measurements and has an overall measurement time of 80 seconds. Pandora is a part of a network of identical instruments known as the Pandonia Global Network.

Generic-Atmospheric State (Gen-AtmsState) refers to non-specific instruments on a platform used for measurements of atmospheric state parameters. These are typically in situ sensors that measure temperature, pressure, humidity, and wind speed/direction. Types of atmospheric state instruments include thermometers, hygrometers, barometers, and anemometers.

The NASA Micro-Pulse Lidar Network (MPLNET) is a global ground-based network of Micro-Pulse Lidar (MPL) systems that has been active since 1999. MPLNET provides continuous measurements of aerosol and cloud vertical structure as well as boundary layer height from the surface up to 30 km. The MPL systems operate at a wavelength range of 523-532 nm and have a vertically-resolved spatial resolution of 30 to 75 m depending on the station. Many of the MPLNET sites are co-located with sites in the NASA Aerosol Robotic Network (AERONET) to help reduce errors in retrievals.

Generic-Chemistry Related Sensors (Gen-Chemistry) refers to non-specific instruments on a platform used for atmospheric chemistry measurements. These are typically in situ analyzers that measure various chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratio, composition, particle size, optical properties, and particle size distribution.

The AErosol RObotic NETwork (AERONET) is a federated network of ground-based remote sensing aerosol sensors established by NASA and the PHOtométrie pour le Traitement Opérationnel de Normalisation Satellitaire (PHOTONS) in 1993. Each AERONET site consists of a CIMEL Electronique sunphotometer that provides measurements of sun irradiance and sky radiances. These measurements can be used to retrieve aerosol properties such as aerosol optical depth and extinction. The sunphotometers operate across nine wavelengths (340, 380, 440, 500, 675, 870, 937, 1020, and 1640 nm) and provide aerosol measurements approximately every 15 min. AERONET sites are located across the world, making it possible to map around 90% of the Earth’s surface.

This data will be added in future versions

This data will be added in future versions

The Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties such as size distribution, number concentration, and scattering and absorption coefficient. LARGE consists of multiple instruments including the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Particle-Into-Liquid Sampler (PILS), Particle Soot Absorption Photometer (PSAP), Cloud and Aerosol Spectrometer (CAS), Cloud Imaging Probe (CIP), and additional cloud and aerosol sensors. The LARGE instruments operate across the 450-700 nm wavelength range, can detect particles in the size range between 0.003-20μm, and have a measurement frequency of 1 Hz. It is typically used for airborne measurements, but it also can be deployed on ground-based platforms such as vehicles.

The Scanning Mobility Particle Sizer (SMPS) is an in situ airborne or ground-based aerosol sensor manufactured by TSI Incorporated. SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles to determine the size distribution. It also measures the number of aerosol particles by using a condensation particle counter (CNC). It can detect particles within the size range of 10-1000 nm and can provide measurements typically around 10 seconds per scan.

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.

Generic-Atmospheric State (Gen-AtmsState) refers to non-specific instruments on a platform used for measurements of atmospheric state parameters. These are typically in situ sensors that measure temperature, pressure, humidity, and wind speed/direction. Types of atmospheric state instruments include thermometers, hygrometers, barometers, and anemometers.

Nephelometers are in situ airborne or ground-based optical sensors. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate across three wavelengths: 450 nm, 550 nm, and 700 nm, and have a typical time resolution of 1 Hz.

The Condensation Nuclei Counter (CNC) is optical method for counting atmospheric aerosol particles.

Generic-Chemistry Related Sensors (Gen-Chemistry) refers to non-specific instruments on a platform used for atmospheric chemistry measurements. These are typically in situ analyzers that measure various chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratio, composition, particle size, optical properties, and particle size distribution.

The Atmospheric Vertical Observations of CO2 in the Earth’s Troposphere (AVOCET) is an airborne in situ spectrometer developed by NASA’s Langley Research Center (LaRC). AVOCET uses a differential, non-dispersive infrared spectrometer to provide high-resolution measurements of carbon dioxide (CO2). It operates at the 4.26 μm CO2 absorption band and has a measurement frequency of 5 Hz. AVOCET has been deployed in several field investigations since the early 1990s and has participated in over 450 science flights.

This data will be added in future versions

Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentration. CPCs measure aerosol concentration by condensing fluid onto the particles, allowing them to grow to more detectable sizes for optical scattering. Typically, CPCs can detect particles with a size range of 7 nm-3 μm, can measure particle concentrations up to 100,000 particles/cc, and can provide measurements at 1-second intervals. CPCs are manufactured by TSI Incorporated and can be deployed on airborne, shipborne, and ground-based platforms.

The Particle Into Liquid Sampler (PILS) is an in situ aerosol sampler manufactured by Brechtel Manufacturing Inc. PILS can be utilized by both ground-based and airborne platforms to collect continuous measurements of ambient aerosol bulk composition. The particles sampled by PILS are mixed with saturated water vapor to produce droplets that are analyzed by either an ion chromatograph (IC) or a total organic carbon detector (TOC). PILS can measure aerosol particles with a size range of 70 nm to 2.5 μm and has a time resolution of 3 min for airborne measurements and 15 min for ground-based.

The Difference Frequency Generation Absorption Spectrometer is an instrument designed to measure formaldehyde in the atmosphere. It measures the gas using an infrared laser. The instrument uses two lasers that operate at 1562nm and 1083nm. The instrument was used in multiple campaigns, and has since been replaced by the Compact Atmospheric Multispecies Spectrometer (CAMS).

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 Thermal-Dissociation Laser Induced Fluorescence (TD-LIF) is an in situ airborne sensor developed at UC Berkeley. It uses a combination of the TD and LIF techniques to measure nitrogen dioxide (NO2), peroxynitrates, nitric acid (HNO3), and other stable organic nitrates in the atmosphere. TD-LIF operates at the 585 nm wavelength and has a typical measurement frequency of 1 Hz.

The Scanning Mobility Particle Sizer (SMPS) is an in situ airborne or ground-based aerosol sensor manufactured by TSI Incorporated. SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles to determine the size distribution. It also measures the number of aerosol particles by using a condensation particle counter (CNC). It can detect particles within the size range of 10-1000 nm and can provide measurements typically around 10 seconds per scan.

LI-COR Gas Analyzer is an in situ gas analyzer manufactured by LI-COR. They can be deployed on aircraft, research vessels, vehicles, balloons, and ground-based platforms. They provide measurements of various trace gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O). Most models use Optical Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to collect measurements. LI-COR gas analyzers have a typical measurement rate of 1 Hz and an operating temperature range of -25 to 45 degrees Celsius.

The Proton Transfer Mass Spectrometer (PTR-MS) is an in situ airborne and ground-based spectrometer designed by the University of Innsbruck in Austria. It measures volatile organic compounds (VOCs) without sample preparation at very low concentrations. PTR-MS uses chemical ionization mass spectroscopy allowing for fast and highly sensitive detection of VOCs. It has a 0.5 to 1 s signal integration time.

This data will be added in future versions

The Optical Particle Counter is an instrument based on the principle of light scattering from particles. It is a real time instrument that is typically used to measure particles above 0.05 μm in diameter.

The Differential Absorption Carbon monOxide Measurements (DACOM) is an airborne in situ spectrometer system. It uses the differential absorption technique and an infrared tunable diode laser (TDL) to collect measurements of nitrous oxide (N2O), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) in the atmosphere. DACOM operates across the 4.7, 4.5, and 3.3 μm wavelengths to access the absorption lines for CO, N2O, and CH4. It has a measurement frequency of 5 Hz and a precision of about 1 ppbv.

The Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) is an in situ spectrometer manufactured by Droplet Measurement Technologies. It can be utilized on both airborne and ground-based platforms to measure aerosol size distribution and concentration. UHSAS determines the particle size by detecting the peak light signals of the aerosol particles which are illuminated by a 1054 nm laser. UHSAS can sample particles within the 60 - 1000 nm size range and has a sampling frequency of 10 Hz.

The Cloud Absorption Radiometer (CAR) is an airborne multi-wavelength scanning radiometer developed by Goddard Space Flight Center (GSFC). CAR provides measurements of scattered radiance and bidirectional reflectance of the surface across 14 spectral bands in the visible and near-infrared wavelengths (0.34-2.30 µm). It also acquires imagery of cloud and Earth surface features. CAR has a scan rate of 1.67 Hz (100 rpm) and has a spatial resolution of 4m at nadir for an altitude of 200m above ground level.

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 Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. APS measures aerodynamic particles in the 0.5-20 μm size range. It also measures the light-scattering intensity of the particles in the 0.37-20 μm optical size range. APS provides particle size distributions for 52 channels at a typical sampling time of 1 second. It uses a laser diode operating at 655 nm and has a size resolution of 0.02 μm at 1 μm. APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is optical method for counting atmospheric aerosol particles.

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 Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties such as size distribution, number concentration, and scattering and absorption coefficient. LARGE consists of multiple instruments including the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Particle-Into-Liquid Sampler (PILS), Particle Soot Absorption Photometer (PSAP), Cloud and Aerosol Spectrometer (CAS), Cloud Imaging Probe (CIP), and additional cloud and aerosol sensors. The LARGE instruments operate across the 450-700 nm wavelength range, can detect particles in the size range between 0.003-20μm, and have a measurement frequency of 1 Hz. It is typically used for airborne measurements, but it also can be deployed on ground-based platforms such as vehicles.

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 Cloud Imaging Probe (CIP) is an in situ airborne optical array probe manufactured by Droplet Measurement Technologies. CIP records cloud particle images by capturing the shadow of the particles as they pass through the laser. It also provides information on the particle size distribution and cloud liquid water content. CIP has a typical resolution of 25 μm and can measure particles in the size range of 12.5 μm - 1.55 mm.

The Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It uses Beer's Law to measure the change in light transmission of aerosol particles. These measurements can be used to derive aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a temporal resolution of 1 second. It is typically deployed on aircraft, but it can be deployed on other platforms such as ships and vehicles.

Nephelometers are in situ airborne or ground-based optical sensors. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate across three wavelengths: 450 nm, 550 nm, and 700 nm, and have a typical time resolution of 1 Hz.

Ozonesondes are in situ balloon-borne instruments used to measure ozone concentration profiles. An ozonesonde consists of an electrochemical ozone sensor connected with a meteorological radiosonde to collect ozone, temperature, pressure, and humidity measurements as it ascends through the atmosphere. It provides ozone profile measurements at a resolution of 100 to 150 m. Ozonesondes have a typical measurement rate of 0.1 Hz and can collect profiles up to around 35 km.

Radiosondes are a balloon-borne instrument package used to collect profile measurements of pressure, temperature, humidity, and winds. These sensors are connected to a radio transmitter that sends the measurements to a ground receiver typically operating in the 400-406 MHz range. They typically provide measurements at 1-6 seconds, depending on the type and manufacturer of the radiosonde. Radiosondes are used for weather forecasting, ground truth satellite data, atmospheric research, and input for weather prediction models.