The Smoke/Sulfates, Clouds, and Radiation (SCAR) experiment was a NASA field study focused on the atmospheric effects of aerosols from sources like biomass burning and urban emissions. SCAR included three deployments: SCAR-Atlantic (SCAR-A), SCAR-California (SCAR-C), and SCAR-Brazil (SCAR-B). SCAR-A studied urban and industrial aerosols over the mid-Atlantic region in July 1993. Both SCAR-C and SCAR-B examined smoke aerosols from biomass burning over the Pacific Northwest and Central Brazil during the boreal fall of 1994 and the austral winter of 1995. The NASA ER-2, equipped with the MODIS Airborne Simulator (MAS) and the Airborne Visible/Infrared Imaging Spectrometer - Classic (AVIRIS-C), collected measurements to validate MODIS fire and aerosol products. Additional aerosol and cloud property data were gathered using the University of Washington C-131A aircraft and ground-based sunphotometers. SCAR was funded by NASA’s Radiation Sciences Program.
Sulfates, Clouds and Radiation - Atlantic, Sulfates, Clouds and Radiation - America, Smoke, Clouds and Radiation - Brazil, Smoke, Clouds and Radiation - California, SCAR-A, SCAR-B, SCAR-C
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.
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.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Pressure
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
Earth Science > Atmosphere > Atmospheric Temperature > Surface Temperature > Air Temperature
Generic-Radiometers refer to non-specific radiometers on a platform. These are typically passive microwave radiometers that measure brightness temperature. Radiometers can be used to retrieve temperature and water vapor profiles, soil moisture content, ocean salinity, precipitation and cloud properties, and vegetation.
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
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 Scanning Mobility Particle Sizer (SMPS) is an in situ aerosol sensor that can be operated on airborne or ground-based platforms, manufactured by TSI Incorporated. SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles, which helps determine the size distribution. It also counts the number of aerosol particles using a condensation particle counter (CPC). It detects particles in the size range of 10-1000 nm and typically takes about 10 seconds to complete each scan.
Earth Science > Atmosphere > Aerosols
Earth Science > Atmosphere > Aerosols > Chemical Composition
The Passive-Cavity Aerosol Spectrometer Probe (PCASP) is an in situ airborne optical spectrometer manufactured by Droplet Measurement Technologies. It detects light scattered by particles to determine aerosol size distribution and concentration within the 0.1 to 3.0 μm range. PCASP operates at a wavelength of 632 nm and typically samples at 10 Hz.
The Particule Volume Matter (PVM-100A) is an in situ airborne cloud probe manufactured by Gerber Scientific. It measures liquid water content and the effective radius of cloud droplets by measuring the scattering intensity proportional to the droplets' density and particle surface area density. PVM-100A operates at 780 nm and has a measurement rate of up to 5000 Hz. It can measure droplets in the size range of 3-50 μm diameter. The ground-based model of this instrument is PVM-100.
The Cloud Absorption Radiometer (CAR) is an airborne multichannel scanning radiometer developed by the Goddard Space Flight Center (GSFC). CAR provides measurements of scattered radiance and bidirectional surface reflectance across 14 spectral bands in 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, at an altitude of 200 meters above ground.
Earth Science > Atmosphere > Clouds > Cloud Radiative Transfer
The 2D-C/P Hydrometeor Imaging Probe (2D-C/P) is an in situ, airborne instrument that captures images of hydrometeors. It records these images by detecting the illuminated or shadowed states of the photodiode array as the shadow of the hydrometeors passes over. 2D-C/P also offers measurements of particle size distribution, cloud droplet concentration, and hydrometeor shape. Typically, 2D-C/P probes have an image resolution of 25 micrometers and can image hydrometeors with diameters up to 1600 micrometers.
The Condensation Nuclei Counter (CNC) is optical method for
counting atmospheric aerosol particles.
Earth Science > >
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 King Probe is an in situ airborne cloud instrument developed by Warren King (Commonwealth Scientific and Industrial Research Organisation) and manufactured by Particle Measuring Systems (PMS) and Droplet Measurement Technologies (DMT). The King Probe measures cloud liquid water content (LWC) by detecting the heat released when water droplets vaporize. It operates at a constant temperature of approximately 100°C and has a data output rate of 1 to 10 Hz. The probe is commonly used in studies of cloud microphysics and aircraft icing.
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 University of Washington-Georgia Tech Lidar System is an airborne lidar system that uses a downward-pointing, neodymium-doped yttrium aluminum garnet (Nd-YAG) laser. It was designed by Georgia Tech to be mounted on the University of Washington C-131A research aircraft. It is frequency doubled to operate at both 532 nm and 1064 nm wavelengths, allowing it to measure lidar backscatter to retrieve profiles of aerosol optical properties. It has a pulse repetition rate of 10 Hz and a digitization rate of 25 or 50 ns, providing a vertical resolution of 7.5 and 15 meters, respectively. Its horizontal resolution ranges from 40 to 80 meters.
Nephelometers are in situ optical sensors that can be airborne or ground-based. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate at three wavelengths: 450 nm, 550 nm, and 700 nm, with a typical time resolution of 1 Hz.
The MODIS Airborne Simulator (MAS) is an airborne multispectral spectrometer designed to simulate the satellite instrument Moderate-Resolution Imaging Spectrometer (MODIS). MAS operates over 50 spectral channels in the 0.55 to 14.2 μm range, providing high-resolution images of clouds and surface features. It has a horizontal spatial resolution of 50 meters and a swath width of about 36 kilometers at an altitude of 20 km at nadir. Its scan rate is 6.25 Hz, with each scan line containing 716 pixels.
The Airborne Visible/Infrared Imaging Spectrometer - Classic (AVIRIS-C) is a passive imaging spectrometer developed at the Jet Propulsion Laboratory (JPL). It collects visible and infrared images across 224 spectral channels in the 380 to 2510 nm range. It has a horizontal resolution of 20 m and a swath width of 12 km at an altitude of 20 km. It operates at a scan rate of 12 Hz. AVIRIS-C has been replaced by AVIRIS-Next Generation (AVIRIS-NG), but it still remains in use.
Sunphotometers are passive optical sensors that measure the amount of sunlight. They are pointed directly at the sun to measure direct sunlight and not sunlight scatter from aerosols. These measurements can be used to determine the aerosol optical depth by following Beer’s Law. Sunphotometers have been deployed on aircraft, research vessels, and field sites for aerosol research and monitoring.
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 includes a CIMEL Electronique sunphotometer that measures sun irradiance and sky radiances. These measurements are used to determine aerosol properties such as aerosol optical depth and extinction. The sunphotometers operate at nine wavelengths (340, 380, 440, 500, 675, 870, 937, 1020, and 1640 nm) and provide aerosol data approximately every 15 minutes. AERONET sites are distributed worldwide, enabling mapping of about 90% of the Earth’s surface.
The MODIS Airborne Simulator (MAS) is an airborne multispectral spectrometer designed to simulate the satellite instrument Moderate-Resolution Imaging Spectrometer (MODIS). MAS operates over 50 spectral channels in the 0.55 to 14.2 μm range, providing high-resolution images of clouds and surface features. It has a horizontal spatial resolution of 50 meters and a swath width of about 36 kilometers at an altitude of 20 km at nadir. Its scan rate is 6.25 Hz, with each scan line containing 716 pixels.
The Cloud Lidar System (CLS) was an airborne lidar system that operated on the ER-2 aircraft. It measured lidar backscatter to determine the height structure of clouds, cloud thickness, and other cloud properties. CLS was also used to determine aerosol properties. It used a Nd-YAG operating at 1064 and 532 nm and had a pulse repetition frequency of 10 Hz. CLS had a horizontal resolution of 20 m and a vertical sampling resolution of 7.5 m.
The Airborne Visible/Infrared Imaging Spectrometer - Classic (AVIRIS-C) is a passive imaging spectrometer developed at the Jet Propulsion Laboratory (JPL). It collects visible and infrared images across 224 spectral channels in the 380 to 2510 nm range. It has a horizontal resolution of 20 m and a swath width of 12 km at an altitude of 20 km. It operates at a scan rate of 12 Hz. AVIRIS-C has been replaced by AVIRIS-Next Generation (AVIRIS-NG), but it still remains in use.
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.
Nephelometers are in situ optical sensors that can be airborne or ground-based. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate at three wavelengths: 450 nm, 550 nm, and 700 nm, with a typical time resolution of 1 Hz.
