The Airborne Southern Hemisphere Ozone Experiment (ASHOE) aimed to investigate the causes of ozone loss in the lower stratosphere and its impact on atmospheric processes in the Southern Hemisphere. ASHOE involved a single deployment in 1994 across New Zealand, Hawaii, Fiji, and the Pacific Ocean. NASA ER-2 collected in situ and remotely sensed ozone measurements, aerosol properties, and trace gases, complemented by ground-based lidar and ozonesonde observations. ASHOE was funded jointly by NASA and NOAA and took place alongside the Measurements for Assessing the Effects of Stratospheric Aircraft (MAESA) investigation.
1994-03-18 — 1994-11-04
Moffett Field, California, Christchurch, New Zealand, Hawaii, Fiji
austral fall, austral spring, austral winter, boreal fall
The NASA Goddard Tropospheric Ozone Lidar (TROPOZ) is a mobile, ground-based lidar that is part of the Tropospheric Ozone Lidar Network (TOLNet). It employs the differential absorption lidar (DIAL) technique to measure ozone at wavelengths of 289 nm and 299 nm. TROPOZ has a range resolution of 15 meters, a repetition rate of 50 Hz, and can produce ozone profiles from 0.35 to 16 km above ground level.
Earth Science > Atmosphere > Air Quality > Tropospheric Ozone
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.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Pressure
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
Earth Science > Atmosphere > Atmospheric Temperature > Upper Air Temperature > Vertical Profiles
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 ACATS is now retired and has been replaced by the Uncrewed Aerial Systems (UAS) Chromatograph for Atmospheric Trace Species (UCATS).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 Multi-sample Aerosol Collection System (MACS) is an in situ airborne aerosol sampling system. It consists of a two-stage impact collector, which allows for the collection of aerosol particles on electron microscope grids for further analysis. MACS can collect particles as small as 0.02 μm for altitudes up to 60,000 feet. MACS can collect around 24 samples per flight.
The Microwave Temperature Profiler (MTP) is an airborne microwave radiometer developed by the Jet Propulsion Laboratory and later modified by NCAR. It measures brightness temperature from oxygen molecules at 56.363 GHz, 57.612 GHz, and 58.363 GHz. These measurements are converted into air temperature through a statistical retrieval process. It samples across 10 viewing angles and has a vertical resolution of 150 m near the aircraft. MTP provides profiles every 17 seconds with about 4 km of horizontal spacing.
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
The Multiple-Angle Aerosol Spectrometer Probe (MASP) is an in situ airborne spectrometer. It measures the light intensity of scatter aerosol particles at 780 nm wavelength across multiple angles to determine particle size and concentration. It can detect particles within the 0.3 to 20 micron size range. MASP typically has a time resolution of 10 seconds.
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 Focused Cavity Aerosol Spectrometer (FCAS) is an in situ airborne optical particle counter developed by Particle Measuring Systems, Inc. FCAS detects light scattered by individual aerosol particles to determine their size distribution. It can detect aerosol particles ranging from 0.06 to 2 μm in size and operate at altitudes up to 20 km. Typically, FCAS provides measurements every 10 seconds.
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 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 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 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 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.
Harvard Water Vapor (HWV) is an in situ airborne hygrometer developed at Harvard University that measures water vapor mixing ratios in the upper troposphere and lower stratosphere. HWV includes two instruments with different methods for detecting water vapor: the Lyman-α photo-fragment fluorescence instrument (LyA) and a tunable diode laser direct absorption instrument (HHH -Harvard Herriott Hygrometer). By combining both instruments, HWV can identify and reduce systematic errors during flight. It provides measurements of water vapor mixing ratio from 1 to 1000 ppmv at 1 Hz and with an accuracy 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
Earth Science > Atmosphere > Atmospheric Water Vapor
The NOAA Frost Point Hygrometer (FPH) is a balloon-borne sensor that collects profile measurements of atmospheric water vapor. It employs the chilled-mirror principle to determine the frost or dew point temperature up to 28 km in the atmosphere. FPH takes measurements with a vertical resolution of 5-10 m and a temporal resolution of 1-2 seconds.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Dew Point Temperature
NOx/NOxy is an in situ chemiluminescence instrument that measures nitrogen oxides and ozone in the atmosphere. It offers a spatial resolution better than 100 meters at typical DC-8 research flight speeds. NOx/NOxy can be used on ground-based, airborne, and shipborne platforms, enabling it to support various atmospheric chemistry and air quality studies.
Earth Science > Atmosphere > Air Quality > Nitrogen Oxides
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 Scanning High-resolution Interferometer Sounder (S-HIS) is an airborne cross-track scanning interferometer developed by the Space Science and Engineering Center at the University of Wisconsin-Madison. It measures emitted thermal radiation between 3.3 and 18 microns with high spectral resolution. These measurements help derive atmospheric profiles of temperature and water vapor in clear-sky conditions. S-HIS has a spatial resolution of 2 km and a swath width of 40 km at an altitude of 20 km at nadir. It operates at a sampling frequency of 0.5 seconds and has an absolute radiance accuracy of 0.2 K.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
Earth Science > Atmosphere > Atmospheric Temperature
Earth Science > Atmosphere > Atmospheric Water Vapor
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 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 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 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.
