The Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) was a NASA campaign conducted to quantify some of the key chemical reaction rates affecting ozone production and loss. It was the first dedicated field mission to acquire atmospheric measurements in support of the Atmospheric Effects of Stratospheric Aircraft (AESA) Program. SPADE consisted of 3 deployments during the boreal spring and fall of 1992 and 1993 across the western United States. NASA’s ER-2 aircraft was equipped with multiple sensors utilized to measure and analyze trace gases along with other chemicals present within the higher portions of Earth’s atmosphere. Balloon soundings were also launched from nearby stations to make similar observations. SPADE was funded by NASA's Upper Atmosphere Research Program.
The Meteorological Measurement System (MMS) is an in situ airborne instrument used for measuring atmospheric state parameters. MMS provides high-resolution and accurate measurements of atmospheric pressure, temperature, and wind direction/speed immediately around the plane. Additional parameters can be derived such as potential temperature, true airspeed, turbulence dissipation rate, and Reynolds number. Measurements of all parameters are typically collected at a rate of 20 Hz.
The Lyman-alpha Hygrometer measures the absorption by water vapor of vacuum-ultraviolet light at the Lyman-alpha wavelength of atomic hydrogen (121.6 nm). Air from outside the aircraft is brought to the absorption cell by a forward facing open-ended cone inlet (SCAI inlet) and exhausted through a scarf tube. The instrument ionizes the water molecules themselves as they pass through. Using a high intensity direct current discharge lamp, light at 121.6nm (called Lyman-alpha light) photodissociates water molecules producing excited OH radicals. Fluorescence is produced as the OH radical emits photons at 309nm. Making use of a phototube sensitive to this wavelength and a counter, the amount of OH can be calculated. The ambient air in the sample diminishes this signal by an amount proportional to the mixing ratio, so knowing the ambient pressure and temperature yields the mixing ratio from which the total water is determined. The instrument is periodically calibrated in flight by injecting a known amount of water vapor directly into the sample.
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 > Vapor Pressure
The Aircraft Laser Infrared Absorption Spectrometer (ALIAS) is a high-resolution spectrometer developed by the Jet Propulsion Laboratory (JPL) to fly aboard the NASA ER-2. ALIAS takes real-time measurements of various nitrogen, carbon, and hydrogen compounds, including NO2, CH4, and HCl. Its ability to be flown at high altitudes paired with its fast sample rate makes the ALIAS an ideal instrument to study atmospheric chemistry processes within polar stratospheric clouds (PSCs).
The Airborne Tunable Laser Absorption Spectrometer (ATLAS) is an in situ airborne spectrometer developed by NASA. ATLAS utilizes second-harmonic absorption spectrometry to measure trace gases in the lower stratosphere such as nitrous oxide, methane, carbon monoxide, and ozone. The laser within ATLAS is tuned to the infrared absorption band of the target gas and is frequency modulated at 2 kHz with the second-harmonic detection occurring at 4 kHz. ATLAS provides measurements at a time resolution of 1 s and has a spatial resolution of about 200 m when deployed on the ER-2 aircraft.
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 the 254 nm wavelength allowing it to calculate the ozone number density due to the accurate ozone absorption cross section at that wavelength. It has a sampling rate of 2 Hz and a horizontal resolution of 100 to 200 meters at typical research flight speeds.
Earth Science > Atmosphere > Air Quality > Tropospheric Ozone
The Meteorological Measurement System (MMS) is an in situ airborne instrument used for measuring atmospheric state parameters. MMS provides high-resolution and accurate measurements of atmospheric pressure, temperature, and wind direction/speed immediately around the plane. Additional parameters can be derived such as potential temperature, true airspeed, turbulence dissipation rate, and Reynolds number. Measurements of all parameters are typically collected at a rate of 20 Hz.
The Lyman-alpha Hygrometer measures the absorption by water vapor of vacuum-ultraviolet light at the Lyman-alpha wavelength of atomic hydrogen (121.6 nm). Air from outside the aircraft is brought to the absorption cell by a forward facing open-ended cone inlet (SCAI inlet) and exhausted through a scarf tube. The instrument ionizes the water molecules themselves as they pass through. Using a high intensity direct current discharge lamp, light at 121.6nm (called Lyman-alpha light) photodissociates water molecules producing excited OH radicals. Fluorescence is produced as the OH radical emits photons at 309nm. Making use of a phototube sensitive to this wavelength and a counter, the amount of OH can be calculated. The ambient air in the sample diminishes this signal by an amount proportional to the mixing ratio, so knowing the ambient pressure and temperature yields the mixing ratio from which the total water is determined. The instrument is periodically calibrated in flight by injecting a known amount of water vapor directly into the sample.
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 > Vapor Pressure
The Aircraft Laser Infrared Absorption Spectrometer (ALIAS) is a high-resolution spectrometer developed by the Jet Propulsion Laboratory (JPL) to fly aboard the NASA ER-2. ALIAS takes real-time measurements of various nitrogen, carbon, and hydrogen compounds, including NO2, CH4, and HCl. Its ability to be flown at high altitudes paired with its fast sample rate makes the ALIAS an ideal instrument to study atmospheric chemistry processes within polar stratospheric clouds (PSCs).
The Airborne Tunable Laser Absorption Spectrometer (ATLAS) is an in situ airborne spectrometer developed by NASA. ATLAS utilizes second-harmonic absorption spectrometry to measure trace gases in the lower stratosphere such as nitrous oxide, methane, carbon monoxide, and ozone. The laser within ATLAS is tuned to the infrared absorption band of the target gas and is frequency modulated at 2 kHz with the second-harmonic detection occurring at 4 kHz. ATLAS provides measurements at a time resolution of 1 s and has a spatial resolution of about 200 m when deployed on the ER-2 aircraft.
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 the 254 nm wavelength allowing it to calculate the ozone number density due to the accurate ozone absorption cross section at that wavelength. It has a sampling rate of 2 Hz and a horizontal resolution of 100 to 200 meters at typical research flight speeds.
Earth Science > Atmosphere > Air Quality > Tropospheric Ozone
The Lyman-alpha Hygrometer measures the absorption by water vapor of vacuum-ultraviolet light at the Lyman-alpha wavelength of atomic hydrogen (121.6 nm). Air from outside the aircraft is brought to the absorption cell by a forward facing open-ended cone inlet (SCAI inlet) and exhausted through a scarf tube. The instrument ionizes the water molecules themselves as they pass through. Using a high intensity direct current discharge lamp, light at 121.6nm (called Lyman-alpha light) photodissociates water molecules producing excited OH radicals. Fluorescence is produced as the OH radical emits photons at 309nm. Making use of a phototube sensitive to this wavelength and a counter, the amount of OH can be calculated. The ambient air in the sample diminishes this signal by an amount proportional to the mixing ratio, so knowing the ambient pressure and temperature yields the mixing ratio from which the total water is determined. The instrument is periodically calibrated in flight by injecting a known amount of water vapor directly into the sample.
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 > Vapor Pressure
The Aircraft Laser Infrared Absorption Spectrometer (ALIAS) is a high-resolution spectrometer developed by the Jet Propulsion Laboratory (JPL) to fly aboard the NASA ER-2. ALIAS takes real-time measurements of various nitrogen, carbon, and hydrogen compounds, including NO2, CH4, and HCl. Its ability to be flown at high altitudes paired with its fast sample rate makes the ALIAS an ideal instrument to study atmospheric chemistry processes within polar stratospheric clouds (PSCs).
The Airborne Tunable Laser Absorption Spectrometer (ATLAS) is an in situ airborne spectrometer developed by NASA. ATLAS utilizes second-harmonic absorption spectrometry to measure trace gases in the lower stratosphere such as nitrous oxide, methane, carbon monoxide, and ozone. The laser within ATLAS is tuned to the infrared absorption band of the target gas and is frequency modulated at 2 kHz with the second-harmonic detection occurring at 4 kHz. ATLAS provides measurements at a time resolution of 1 s and has a spatial resolution of about 200 m when deployed on the ER-2 aircraft.
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 the 254 nm wavelength allowing it to calculate the ozone number density due to the accurate ozone absorption cross section at that wavelength. It has a sampling rate of 2 Hz and a horizontal resolution of 100 to 200 meters at typical research flight speeds.
Earth Science > Atmosphere > Air Quality > Tropospheric Ozone
