The Stratospheric Photochemistry, Aerosols, and Dynamics Expedition (SPADE) was a NASA campaign that measured key chemical reaction rates involved in ozone formation and depletion. It was the first dedicated field mission to collect atmospheric data for the Atmospheric Effects of Stratospheric Aircraft (AESA) Program. SPADE included three deployments during the spring and fall of 1992 and 1993 across the western United States. NASA’s ER-2 aircraft was equipped with multiple sensors to detect and analyze trace gases and other chemicals in the upper atmosphere. Balloon soundings were also launched from nearby stations to collect similar data. SPADE was funded by NASA's Upper Atmosphere Research Program.
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.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
The Composition and Photodissociative Flux Measurement (CPFM) is an in situ airborne spectroradiometer used for the measurement of direct and scattered solar irradiance. It is based on a holographic, diffraction grating, and a 1024-element photodiode array detector. It measures the solar flux on a horizontal surface and the limb and apparent brightness below the flight level. CPFM operates in the 300-770 nm wavelength range. CPFM has also been used for ground-based measurements.
Earth Science > Atmosphere > Atmospheric Radiation > Solar Irradiance
The Airborne Laser Infrared Absorption Spectrometer (ALIAS) is an in situ airborne spectrometer developed by the Jet Propulsion Laboratory. It can also be deployed on balloons. It uses mid-infrared (3.4–8 μm) absorption spectroscopy to measure atmospheric gases such as nitrous oxide (N2O), nitrogen dioxide (NO2), nitric acid (HNO3), hydrochloric acid (HCl), carbon monoxide (CO), and methane (CH4). ALIAS has a vertical resolution of 15 m and a time resolution of 3 seconds or less.
The Multiple Axis Resonance Fluorescence Chemical Conversion Detector for ClO and BrO (ClO/BrO) is an in situ airborne analyzer operated by Harvard University. It provides measurements of chlorine monoxide (ClO) and bromine monoxide (BrO) in the upper troposphere and lower stratosphere. ClO and BrO are converted to chlorine (Cl) and bromine (Br) through the addition of nitric oxide (NO) in the sample air. Cl and Br concentrations are detected through resonance scattering in the vacuum ultraviolet (119 nm) to determine ClO and BrO concentrations. ClO/BrO has a detection limit greater than 1 pptv.
The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, allowing CCN particles to become detectable. The particles are then measured with an optical particle counter (OPC). CNC can detect 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 Meteorological Measurement System (MMS) is an in situ airborne instrument used to measure atmospheric state parameters. MMS provides high-resolution, accurate measurements of atmospheric pressure, temperature, and wind direction and speed immediately around the plane. Additional parameters that can be derived include potential temperature, true airspeed, turbulence dissipation rate, and Reynolds number. Measurements of all parameters are typically collected at a rate of 20 Hz.
The Airborne Tunable Laser Absorption Spectrometer (ATLAS) is an in situ airborne spectrometer developed by NASA. ATLAS uses second-harmonic absorption spectrometry to measure trace gases in the lower stratosphere, such as nitrous oxide, methane, carbon monoxide, and ozone. The laser inside ATLAS is tuned to the infrared absorption band of the target gas and is frequency modulated at 2 kHz, with second-harmonic detection happening at 4 kHz. ATLAS provides measurements with a time resolution of 1 second and a spatial resolution of about 200 meters when deployed on the ER-2 aircraft.
The High-Sensitivity Fast-Response CO2 Analyzer (Harvard CO2) is an in situ airborne spectrometer operated by Harvard University. It measures carbon dioxide (CO2) concentrations using a modified nondispersive infrared CO2 analyzer. CO2 mixing ratios are determined by measuring absorption at 4.26 μm. Harvard CO2 has a measurement sampling rate of 0.5 Hz and a precision of 0.05 ppm. Harvard is typically deployed on high-altitude aircraft like the ER-2, but it has been used for balloon-borne measurements.
The Lyman-alpha Hygrometer is an in situ hygrometer designed for deployment on airborne or ground-based platforms. It measures water vapor absorption at the Lyman-alpha wavelength (121.6 nm) of atomic hydrogen to determine the total water content in the atmosphere. It has a detection limit of 0.1 ppmv and a typical data acquisition rate of 1 second. The Lyman-alpha hygrometer provides water vapor measurements with an accuracy of 6% and a precision of 5%.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles > Water Vapor Mixing Ratio Profiles
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Total Precipitable Water
Earth Science > Atmosphere > Atmospheric Water Vapor
The NOAA Dual-Beam UV-Absorption Ozone Photometer (NOAA-O3) is an in situ optical balloon-borne and airborne instrument that measures ozone concentrations in the troposphere and lower stratosphere. It operates at a wavelength of 254 nm, enabling it to calculate ozone number density due to the precise ozone absorption cross section at that wavelength. It has a sampling rate of 2 Hz and a horizontal resolution of 100 to 200 meters during typical research flights.
Earth Science > Atmosphere > Air Quality > Tropospheric Ozone
The Harvard Hydroxyl Experiment (HOx) is an in situ laser-induced fluorescence (LIF) sensor developed by Harvard University. It uses LIF centered at 309 nm to measure hydroxyl radical (OH). The OH is then converted into its first electronic state using a tunable ultraviolet laser near 282 nm. The hydroperoxyl radical (HO2) is measured as OH after chemical titration with nitric oxide. HOx has a short integration time of less than 20 seconds.
The Forward Scattering Spectrometer Probe (FSSP) is an in situ airborne optical particle counter initially developed by Particle Measuring Systems, Inc. It determines particle size distribution by measuring the light intensity scattered by individual particles within the cloud. FSSP can detect particles ranging from 0.5 to 47 μm in diameter. It functions at a wavelength of 633 nm and typically samples at a rate of 1 Hz.
The Airborne Chromatograph for Atmospheric Trace Species (ACATS) was an in situ airborne four-channel gas chromatograph. It used electron capture detection (ECD) to measure various halocarbons and trace gases in the stratosphere. Measurements are provided every 125 or 250 seconds, depending on the gas species. ACATS is now retired and has been replaced by the Uncrewed Aerial Systems (UAS) Chromatograph for Atmospheric Trace Species (UCATS).
The Airborne Laser Infrared Absorption Spectrometer (ALIAS) is an in situ airborne spectrometer developed by the Jet Propulsion Laboratory. It can also be deployed on balloons. It uses mid-infrared (3.4–8 μm) absorption spectroscopy to measure atmospheric gases such as nitrous oxide (N2O), nitrogen dioxide (NO2), nitric acid (HNO3), hydrochloric acid (HCl), carbon monoxide (CO), and methane (CH4). ALIAS has a vertical resolution of 15 m and a time resolution of 3 seconds or less.
The Airborne Tunable Laser Absorption Spectrometer (ATLAS) is an in situ airborne spectrometer developed by NASA. ATLAS uses second-harmonic absorption spectrometry to measure trace gases in the lower stratosphere, such as nitrous oxide, methane, carbon monoxide, and ozone. The laser inside ATLAS is tuned to the infrared absorption band of the target gas and is frequency modulated at 2 kHz, with second-harmonic detection happening at 4 kHz. ATLAS provides measurements with a time resolution of 1 second and a spatial resolution of about 200 meters when deployed on the ER-2 aircraft.
The High-Sensitivity Fast-Response CO2 Analyzer (Harvard CO2) is an in situ airborne spectrometer operated by Harvard University. It measures carbon dioxide (CO2) concentrations using a modified nondispersive infrared CO2 analyzer. CO2 mixing ratios are determined by measuring absorption at 4.26 μm. Harvard CO2 has a measurement sampling rate of 0.5 Hz and a precision of 0.05 ppm. Harvard is typically deployed on high-altitude aircraft like the ER-2, but it has been used for balloon-borne measurements.
The Lyman-alpha Hygrometer is an in situ hygrometer designed for deployment on airborne or ground-based platforms. It measures water vapor absorption at the Lyman-alpha wavelength (121.6 nm) of atomic hydrogen to determine the total water content in the atmosphere. It has a detection limit of 0.1 ppmv and a typical data acquisition rate of 1 second. The Lyman-alpha hygrometer provides water vapor measurements with an accuracy of 6% and a precision of 5%.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles > Water Vapor Mixing Ratio Profiles
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Total Precipitable Water
Earth Science > Atmosphere > Atmospheric Water Vapor
The NOAA Dual-Beam UV-Absorption Ozone Photometer (NOAA-O3) is an in situ optical balloon-borne and airborne instrument that measures ozone concentrations in the troposphere and lower stratosphere. It operates at a wavelength of 254 nm, enabling it to calculate ozone number density due to the precise ozone absorption cross section at that wavelength. It has a sampling rate of 2 Hz and a horizontal resolution of 100 to 200 meters during typical research flights.
Earth Science > Atmosphere > Air Quality > Tropospheric Ozone
