Arctic Research of the Composition of the Troposphere from Aircraft and Satellites

The Research Scanning Polarimeter (RSP) is an airborne, passive polarimeter developed by SpecTIR Corporation. It measures total radiance and linear polarization across nine spectral bands spanning the visible and infrared wavelengths (410-2250 nm). These measurements can be used to determine aerosol and cloud properties. RSP has a time resolution of 0.8 seconds, a field of view of 14 mrad, and a horizontal resolution of approximately 100 meters at an altitude of 5 km.

The High Spectral Resolution Lidar (HSRL) is an airborne lidar system developed at NASA Langley Research Center (LaRC). It uses the HSRL technique at 532 nm and the standard backscatter technique at 1064 nm to provide profiles of aerosol backscatter, extinction, and depolarization. Aerosol backscatter and depolarization profiles typically have a vertical resolution of 30 m and a horizontal resolution of about 1 km. Extinction profiles have a vertical resolution of 300 m and a horizontal resolution of approximately 6 km. HSRL is usually flown during investigations to validate observations from the CALIPSO spaceborne lidar.

The Differential Mobility Analyzer (DMA) is an in situ device that measures particle electrical mobility to determine their size distribution. It primarily measures aerosols between 10 and 1,000 nm in diameter. The DMA can be used for airborne, ground-based, and laboratory measurements.

The Carbon monOxide by Attenuated Laser Transmission (COBALT) is an in situ airborne spectrometer developed by Los Gatos Research. It uses off-axis integrated cavity output spectroscopy (OA-ICOS) to measure carbon monoxide in the troposphere and at the tropopause. COBALT operates at a wavelength of 4.60 μm and has a typical sampling rate of 1 Hz. COBALT delivers measurements with a precision of 0.2 ppbv and does not require regular calibration.

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

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 chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratios, composition, particle size, optical properties, and particle size distribution.

The Optical Particle Counter (OPC) is an optical instrument that measures aerosol particle size and concentration. It determines particle size and concentration by detecting the intensity of scattered light. Most OPCs operate in the visible to near-infrared range (500-1100 nm) and have a time resolution of 1 second. They are typically used to measure particles larger than 0.5 μm in diameter. OPCs can be used for both airborne and ground-based applications.

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).

Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentrations. CPCs determine aerosol concentrations by condensing a fluid onto particles, causing them to grow to sizes detectable by optical scattering. Typically, CPCs detect particles from 7 nm to 3 μm, measure concentrations up to 100,000 particles per cubic centimeter, and provide readings every second. CPCs are manufactured by TSI Incorporated and can be used on airborne, shipborne, and ground-based platforms.

The Cloud Absorption Radiometer (CAR) is an airborne multichannel scanning radiometer developed by the Goddard Space Flight Center (GSFC). CAR measures scattered radiance and bidirectional surface reflectance across 14 spectral bands spanning the visible and near-infrared wavelengths (0.34-2.30 µm). It also captures imagery of cloud and surface features on Earth. CAR has a scan rate of 1.67 Hz (100 rpm) and a spatial resolution of 4 meters at nadir from an altitude of 200 meters above ground.

Broadband Radiometers (BBR) are modified versions of the Kipp & Zonen CM-22 pyranometers and CG-4 pyrgeometers. They have been adapted for use on airborne platforms through specialized instrument housings and signal amplification. BBR measures solar irradiance in the 0.2-3.6 μm wavelength range and infrared (IR) irradiance in the 4.5-42 μm range. These measurements can be used to derive net irradiance, radiative forcing, absorption, and albedo. It has a typical sampling rate of 1 Hz and a hemispheric field of view.

The Solar Spectral Flux Radiometer (SSFR) is an airborne radiometer developed by the Ames Atmospheric Radiation Group. It measures solar spectral irradiance in the troposphere. SSFR operates across 300-2150 nm and provides a spectral resolution of 8-12 nm. It typically collects data at 1 Hz and has a radiometric accuracy of 3%.

The Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. It measures aerodynamic particles in the 0.5-20 μm size range and light-scattering intensity in the 0.37-20 μm optical size range. The 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. The APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies and TSI, Inc. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, making CCN particles detectable. The particles are then measured by an optical particle counter (OPC). The CNC detects particles from 0.75 to 10 μm in diameter and operates at a sampling rate of 1 Hz. It is suitable for both airborne and ground-based operations.

The Tandem Differential Mobility Analyzer (TDMA) is an in situ airborne and ground-based analyzer that measures aerosol particle properties, including size distribution and concentration. It measures particles in the size range of 0.013 to 0.75 mm, with a size resolution of 0.013 mm at 0.2 mm. The TDMA is often combined with an Aerodynamic Particle Sizer (APS) to enable measurements of submicron particles. A typical TDMA measurement sequence takes approximately 45 minutes to complete.

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

The Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It applies Beer's Law to measure changes in light transmission caused by aerosol particles. These measurements help determine aerosol absorption and extinction. The PSAP operates at three wavelengths (467, 530, and 660 nm) and has a 1-second time resolution. It is typically deployed on aircraft but can also be used on ships and vehicles.

Spectrometers are instruments that separate and analyze the spectral components of a substance. They typically measure electromagnetic radiation that has been reflected, absorbed, or transmitted by a sample. Spectrometers operate across the ultraviolet to infrared spectrum. The most common types include optical, nuclear magnetic resonance, and mass spectrometers. They can be deployed on aircraft, research vessels, vehicles, and other ground-based platforms.

Thermo Scientific Gas Analyzers are in situ gas analyzers manufactured by ThermoFisher Scientific. They provide precise measurements of trace gases, including ozone, carbon dioxide, carbon monoxide, and sulfur dioxide. Thermo Scientific Gas Analyzers can be deployed on aircraft, research vessels, and ground-based platforms.

The Aethalometer is an in situ aerosol measurement device made by Magee Scientific. It can be used on both airborne and ground-based platforms. It collects aerosols on a filter tape and measures the attenuation of transmitted light to assess black carbon concentrations. The Aethalometer operates across seven optical wavelengths (370, 470, 520, 590, 660, 880, and 950 nm) and provides data at 1 Hz. It has a measurement range of 0-500 μg per cubic meter and a resolution of 0.1 μg per cubic meter.

The Airborne Tunable Laser Absorption Spectrometer (ATLAS) is an in situ airborne spectrometer developed by NASA. ATLAS uses second-harmonic absorption spectroscopy to measure trace gases in the lower stratosphere, including nitrous oxide, methane, carbon monoxide, and ozone. The laser in ATLAS is tuned to the infrared absorption band of the target gas and frequency-modulated at 2 kHz, with second-harmonic detection at 4 kHz. ATLAS provides measurements with a time resolution of 1 second and a spatial resolution of approximately 200 meters.

The Aerosol Mass Spectrometer (AMS) is an in situ spectrometer developed by Aerodyne Research. It uses quadrupole mass spectrometry to measure aerosol chemical composition and properties. It detects particles from 40 nm to 1 micron in size and offers a time resolution of up to 10 Hz. It can be installed on aircraft, research vessels, mobile laboratories, or other ground-based platforms.

The Airborne Tracking Sun Photometer (ATSP) is an airborne instrument that measures direct solar beam transmission. The ATSP captures solar beam transmission across multiple channels spanning wavelengths from 354 to 2139 nm. These measurements can be used to determine aerosol optical depth and other aerosol characteristics. Several versions of this instrument exist, including one developed by the NASA Ames Research Center.

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

The Measurements of Atmospheric Carbon Dioxide Over Northwestern North America (MACDON-NA) is an in situ airborne gas analyzer. It is a modified LI-COR model 6252 infrared gas analyzer that measures atmospheric carbon dioxide (CO2). The CO2 measurement is based on the difference in infrared radiation absorption between two gas sampling cells. MACDON-NA operates at a wavelength of 4.26 μm and a constant pressure of 250 torr. It has a typical response time of 0.1 seconds.

LI-COR Gas Analyzers are in situ gas analyzers manufactured by LI-COR. They can be deployed on aircraft, research vessels, vehicles, balloons, and ground-based platforms. They provide measurements of 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.

Gas Chromatography/Mass Spectrometry (GC-MS) is an in situ measurement technique used to analyze volatile organic compounds (VOCs) in the atmosphere. It uses gas chromatography to separate components of an air sample and mass spectrometry to ionize, identify, and quantify gas species. GC-MS is used to detect VOCs, halocarbons, hydrocarbons, and other pollutants. It can be used for ground-based or airborne operations.

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

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 chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratios, composition, particle size, optical properties, and particle size distribution.

The Proton Transfer Mass Spectrometer (PTR-MS) is an in situ spectrometer developed by the University of Innsbruck in Austria and used both on aircraft and on the ground. It detects volatile organic compounds (VOCs) without sample preparation at very low concentrations. PTR-MS employs chemical ionization mass spectrometry, enabling rapid, highly sensitive VOC detection. It has a signal integration time of 0.5 to 1 second.

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 detect reactive nitrogen species, including nitric acid and peroxyacetyl nitrate (PAN), in the lower atmosphere. GT-CIMS typically has a temporal resolution of 1 second and a detection limit of 10 pptv.

The PAN CIMS instrument, developed by Georgia Tech and NCAR (PAN-CIGAR) is an in situ airborne mass spectrometer. It detects seven peroxyacyl nitrate (PAN) species using thermal dissociation chemical ionization mass spectrometry (TD-CIMS). PAN-CIGAR provides simultaneous, semi-continuous measurements of PAN species with a time resolution of 2 seconds. It has a detection limit of approximately 1 pptv per second for most PAN species.

The Trace Organic Gas Analyzer (TOGA) is an in situ airborne analyzer that measures volatile organic compounds (VOCs) in the atmosphere. It combines fast gas chromatography and mass spectrometry to determine atmospheric mixing ratios of VOCs. It detects a wide range of VOCs with high precision (<3%) and accuracy (20% or better), with a time resolution of 40 seconds per 2-minute cycle.

The Peroxy Radical Chemical Ionization Mass Spectrometer (PerCIMS) is an in situ airborne spectrometer operated by NCAR. It measures peroxy radicals (HO2+RO2) by converting hydroperoxy (HO2) and organic peroxy (RO2) into sulfuric acid (H2SO4), followed by chemical ionization to produce bisulfate ions. Mass spectrometric detection then determines the concentrations of HO2 and HO2+RO2 in the troposphere. PerCIMS typically provides 1-minute averages, with HO2+RO2 values collected during the first half (0-6 s) of the minute and HO2 during the second half (30-36 s).

The Scanning Mobility Particle Sizer (SMPS) is an in situ aerosol sensor manufactured by TSI Incorporated. The SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles, thereby determining the size distribution. It also counts aerosol particles using a condensation particle counter (CPC). It detects particles in the 10-1000 nm size range and typically completes each scan in about 10 seconds. The SMPS can be used on airborne or ground-based platforms.

The Particle Into Liquid Sampler (PILS) is an in situ aerosol sampler manufactured by Brechtel Manufacturing Inc. PILS can be deployed on both ground-based and airborne platforms to collect continuous data on ambient aerosol bulk composition. The particles collected by PILS are mixed with saturated water vapor to form droplets that are analyzed by either an ion chromatograph (IC) or a total organic carbon detector (TOC). PILS can detect aerosol particles ranging from 70 nm to 2.5 μm in size and offers a time resolution of 3 minutes for airborne measurements and 15 minutes for ground-based 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 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 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 specific aerosol species. It can provide samples of nitric acid, chloride, sulfates, nitrates, sodium, potassium, ammonium, and calcium. SAGA has a typical sampling interval of 5 to 15 minutes and a detection limit of 1 to 25 pptv, depending on the species sampled.

NOx/NOxy is an in situ chemiluminescence instrument that measures nitrogen oxides and ozone in the atmosphere. It provides spatial resolution better than 100 meters at typical DC-8 research flight speeds. NOx/NOxy can be deployed on ground-based, airborne, and shipborne platforms, supporting a range of atmospheric chemistry and air quality studies.

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

A Tunable Diode Laser Absorption Spectrometer (TDLAS) is an in situ optical spectrometer used on aircraft or on the ground. TDLAS detects wavelength-dependent absorption of light to measure the concentrations of various trace gases. It can also determine the temperature, pressure, velocity, and mass flux of the gas species when applicable. TDLAS typically has a time resolution of 1 second.

The Thermal-Dissociation Laser Induced Fluorescence (TD-LIF) is an in situ airborne sensor developed at UC Berkeley. It combines 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 585 nm and typically measures at 1 Hz.

The Difference Frequency Generation Absorption Spectrometer (DFGAS) is an in situ airborne spectrometer developed by the National Center for Atmospheric Research (NCAR). It uses difference-frequency generation (DFG) at 3.5 μm by combining two infrared lasers at 1562 and 1083 nm to measure atmospheric formaldehyde. DFGAS collects measurements at 1-second intervals for approximately 60 to 120 seconds, depending on measurement requirements. DFGAS has since been replaced by the Compact Atmospheric Multispecies Spectrometer (CAMS).

The Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. It measures aerodynamic particles in the 0.5-20 μm size range and light-scattering intensity in the 0.37-20 μm optical size range. The 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. The APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies and TSI, Inc. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, making CCN particles detectable. The particles are then measured by an optical particle counter (OPC). The CNC detects particles from 0.75 to 10 μm in diameter and operates at a sampling rate of 1 Hz. It is suitable for both airborne and ground-based operations.

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 measure atmospheric concentrations of nitrous oxide (N2O), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). DACOM operates at 4.7, 4.5, and 3.3 μm to access absorption lines of CO, N2O, and CH4. It has a measurement frequency of 5 Hz and a precision of about 1 ppbv.

The Differential Absorption Lidar (DIAL) is an airborne lidar system developed at NASA’s Langley Research Center (LaRC). It uses four lasers to detect lidar backscatter and provide profiles of ozone and aerosols in the atmosphere. DIAL operates in the ultraviolet (289-300 nm) for ozone detection and in the visible (572-600 nm) and infrared (1064 nm) for aerosols. It has a horizontal spatial resolution of approximately 15 km and a measurement accuracy of 5 ppbv.

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 High Resolution Aerosol Mass Spectrometer (HR-AMS) is an in situ airborne mass spectrometer designed to measure aerosol composition and chemistry. It is a modified version of the Aerodyne Aerosol Mass Spectrometer developed by the University of Colorado. It measures the mass concentrations of aerosol particles ranging from 50 nm to 1 μm. HR-AMS determines aerosol composition by impaction at 600 °C, followed by electron ionization and mass spectral analysis. It has a sampling rate of 1 Hz.

The Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), developed by Droplet Measurement Technologies, is an in situ spectrometer that can be deployed on airborne and ground-based platforms to measure aerosol size distribution and concentration. It determines particle size by detecting peak light signals from aerosol particles illuminated by a 1054 nm laser. It samples particles in the 60–1000 nm size range and operates at a sampling frequency of 10 Hz.

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

The Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It applies Beer's Law to measure changes in light transmission caused by aerosol particles. These measurements help determine aerosol absorption and extinction. The PSAP operates at three wavelengths (467, 530, and 660 nm) and has a 1-second time resolution. It is typically deployed on aircraft but can also be used on ships and vehicles.

The Whole Air Sampler (WAS) is an airborne in situ instrument that collects air samples for analyzing trace gases, including nonmethane hydrocarbons (NMHCs), halocarbons, alkyl nitrates, and various sulfur compounds in the troposphere. Air samples collected by the WAS are then analyzed using gas chromatography and mass spectrometry to identify the gases present. The WAS collects samples every minute, allowing scientists to obtain a clear picture of the environment's chemical composition as research aircraft pass through.

Spectrometers are instruments that separate and analyze the spectral components of a substance. They typically measure electromagnetic radiation that has been reflected, absorbed, or transmitted by a sample. Spectrometers operate across the ultraviolet to infrared spectrum. The most common types include optical, nuclear magnetic resonance, and mass spectrometers. They can be deployed on aircraft, research vessels, vehicles, and other ground-based platforms.

The Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties, including size distribution, number concentration, and scattering and absorption coefficients. LARGE includes 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 over the 450-700 nm wavelength range, detect particles from 0.003 to 20 μm, and measure at 1 Hz. It is primarily used for airborne measurements but can also be deployed on ground-based platforms, such as vehicles.

The Aethalometer is an in situ aerosol measurement device made by Magee Scientific. It can be used on both airborne and ground-based platforms. It collects aerosols on a filter tape and measures the attenuation of transmitted light to assess black carbon concentrations. The Aethalometer operates across seven optical wavelengths (370, 470, 520, 590, 660, 880, and 950 nm) and provides data at 1 Hz. It has a measurement range of 0-500 μg per cubic meter and a resolution of 0.1 μg per cubic meter.

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 from 280 to 650 nm. These measurements can be used to derive photolysis frequencies for several chemical compounds, including 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 CalTech Chemical Ionization Mass Spectrometer (CIT-CIMS) is an in situ airborne single-mass spectrometer. CIT-CIMS uses CF3O-ion chemistry and compact time-of-flight and triple quadrupole spectrometers to measure specific atmospheric trace gases, including nitric acid, hydrogen peroxide, and sulfur dioxide. It was designed with rapid-scan capabilities, enabling operation at high temporal resolution (10 Hz) and detection across a wide mass range. CIT-CIMS is typically used for airborne observations but can also be employed for ground-based measurements.

Ozonesondes are in situ balloon-borne instruments that measure ozone concentration profiles. An ozonesonde consists of an electrochemical ozone sensor connected to a meteorological radiosonde, which collects 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 typically operate at a measurement rate of 0.1 Hz and can collect profiles up to around 35 km.

The Multi-Axis Differential Optical Absorption Spectrometer (MAX-DOAS) is a ground-based passive spectrometer that measures scattered solar light at multiple elevation angles to identify trace gases in the troposphere. MAX-DOAS is designed to minimize residual error in the ultraviolet and visible spectra, enabling detection in both clean and polluted environments. Typical MAX-DOAS instruments operate in the 300-700 nm spectral range with a spectral resolution of 0.4-1.5 nm, depending on the target species.

The UAF Cloud Polarization Lidar (CPL) is a ground-based lidar located at the Arctic Facility for Atmospheric Remote Sensing (AFARS) at the University of Alaska Fairbanks (UAF). It measures lidar backscatter and depolarization ratio using a ruby laser transmitter at 0.694 μm. The UAF CPL has a range resolution of 7.5 m and a time resolution of 10 seconds. It provides lidar depolarization ratio measurements with an accuracy of 0.02.