The Terra/Aqua Experiment was a NASA field investigation to improve the calibration of MODIS on the Terra and Aqua satellites. It consisted of two deployments in the boreal spring of 2001 (TX-2001) and the boreal winter of 2002 (TX-2002) across the Gulf of Mexico and parts of Texas and Oklahoma. NASA ER-2 was equipped with the MODIS Airborne Simulator (MAS), the Scanning High-resolution Interferometer Sounder (S-HIS), the Cloud Physics Lidar (CPL), the NPOESS Aircraft Sounder Testbed-Interferometer (NAST-I), and additional cameras to retrieve cloud and radiative properties and imagery for calibrating MODIS data products. During the 2002 deployment, ER-2 flew over the Department of Energy’s Atmospheric Radiation Measurement (ARM) Cloud and Radiation Testbed (CART) in the southern Great Plains to collect additional calibration ground-truth data.
The MODIS Airborne Simulator (MAS) is an airborne multispectral spectrometer that simulates the Moderate-Resolution Imaging Spectrometer (MODIS) satellite instrument. MAS operates over 50 spectral channels spanning 0.55 to 14.2 μm, producing 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 RC-10 Mapping Camera was an airborne imaging system built by Wild Heerburg. It was a metric mapping camera with a shutter intervalometer for capturing stereo imagery. It operated across the 510 to 900 nm spectral range and had a typical resolution of 1.5 to 4 meters. The camera featured a 9x9 image format and was mounted in the Q-bay, nose pod, and both left and right wing pods of NASA’s ER-2 aircraft.
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 are used to derive atmospheric profiles of temperature and water vapor under 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
Video cameras capture footage of various phenomena for research. They are used on aircraft to provide continuous views of weather and terrain below the flight path. Video cameras are also employed to verify the aircraft's flight track. Additionally, they are deployed at field sites to monitor changes in vegetation, land cover, clouds, air quality, glaciers, and other Earth science phenomena.
The NPOESS Aircraft Sounder Testbed - Interferometer (NAST-I) is an airborne infrared interferometer operated and maintained by NASA Langley Research Center (LaRC). It uses Fourier transform spectroscopy to measure brightness temperature and radiance. NAST-I operates in the 3.7-16.1 µm spectral range with a spectral resolution of 0.25 cm-1. It has a spatial resolution of 2.6 km and a cross-track swath width of 46 km at a flight altitude of 20 km. A complete scan cycle for NAST-I takes approximately 12.2 seconds.
Earth Science > Atmosphere > Atmospheric Temperature > Atmospheric Temperature Indices
Earth Science > Atmosphere > Atmospheric Temperature
Video cameras capture footage of various phenomena for research. They are used on aircraft to provide continuous views of weather and terrain below the flight path. Video cameras are also employed to verify the aircraft's flight track. Additionally, they are deployed at field sites to monitor changes in vegetation, land cover, clouds, air quality, glaciers, and other Earth science phenomena.
The RC-10 Mapping Camera was an airborne imaging system built by Wild Heerburg. It was a metric mapping camera with a shutter intervalometer for capturing stereo imagery. It operated across the 510 to 900 nm spectral range and had a typical resolution of 1.5 to 4 meters. The camera featured a 9x9 image format and was mounted in the Q-bay, nose pod, and both left and right wing pods of NASA’s ER-2 aircraft.
The Cloud Physics Lidar (CPL) is an airborne lidar system designed to provide multi-wavelength measurements of cirrus and sub-visual cirrus clouds, as well as aerosols. It measures lidar backscatter at three wavelengths: 355 nm, 532 nm, and 1064 nm. These measurements can be used to determine cloud optical depth, particle size distribution, extinction profiles, aerosol layers, and other properties. CPL has a vertical resolution of 30 m and a typical horizontal resolution of 200 m. It has a measurement sampling rate of 1 Hz.
The MODIS Airborne Simulator (MAS) is an airborne multispectral spectrometer that simulates the Moderate-Resolution Imaging Spectrometer (MODIS) satellite instrument. MAS operates over 50 spectral channels spanning 0.55 to 14.2 μm, producing 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 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 are used to derive atmospheric profiles of temperature and water vapor under 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
Ceilometers are ground-based remote-sensing instruments that measure cloud ceilings and vertical visibility. They use a laser or another light source to detect backscatter from clouds, precipitation, and aerosols. Ceilometers provide detailed, precise measurements in all weather conditions and are cost-effective to operate. They are commonly used in boundary-layer and cloud research.
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.
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
The Ultra-High Frequency (UHF) wind profiler is a ground-based Doppler radar that measures electromagnetic signals to determine wind speed and direction. UHF wind profilers operate in the 300-1000 MHz frequency range. Their high operating frequency enables high-resolution wind measurements within the boundary layer. NOAA operates a network of radar wind profilers as part of the NOAA Profiler Network (NPN).
The Raman Lidar (RL) is a ground-based lidar system operated by the Department of Energy’s (DoE) Atmospheric Radiation Measurement (ARM) User Facility. It detects Raman backscatter at 355 nm to provide profiles of water vapor, temperature, and aerosol and cloud optical properties. It also detects Raman backscatter from water vapor at 408 nm and from molecular nitrogen at 387 nm to help derive aerosol optical properties and water vapor mixing ratios. It has a range resolution of 7.5 m, a time resolution of 10 seconds, and a pulse repetition frequency of 30 Hz. RL can deliver profile measurements from approximately 200 m to 10 km above ground level.
The Millimeter-Wavelength Cloud Radar (MMCR) is a ground-based radar developed by the NOAA Environmental Technology Laboratory (ETL) for the Department of Energy (DoE) Atmospheric Radiation Measurement (ARM) sites. MMCR provides long-term observations of radar reflectivity, Doppler velocity, spectrum width, and other radar parameters for precipitating and nonprecipitating clouds up to 20 km above ground level (AGL). It is a vertically pointing, single-polarization radar operating at approximately 35 GHz. MMCR has a beamwidth of 0.2 degrees and typical vertical resolutions of 45 and 90 meters.
Microwave radiometers (MWRs) are ground-based instruments manufactured by Radiometrics Corporation and operated by the Atmospheric Radiation Measurement (ARM) Research Facility. MWRs measure brightness temperature at 23.8 and 31.4 GHz to determine column amounts of water vapor and liquid water in the atmosphere. MWRs have a field of view (FOV) ranging from about 5.9 to 4.5 degrees, depending on the channel, and typically have a time resolution of 20 seconds for sky-view observations.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
Earth Science > Atmosphere > Atmospheric Water Vapor
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 Atmospheric Emitted Radiance Interferometer (AERI) is a ground-based passive interferometer developed by the University of Wisconsin Space Science and Engineering Center (UW-SSEC) for the Department of Energy (DoE) Atmospheric Radiation Measurement (ARM) Program. It uses Fourier transform spectroscopy to measure downwelling thermal infrared emissions from the atmosphere. These measurements provide profiles of atmospheric temperature and water vapor and help detect trace gases. AERI operates across the 3.3-19 μm spectral range and up to 25 μm for the extended-range version of the instrument. It has an optimal vertical resolution of 100 meters and completes a full-sky scan about every 20 seconds.
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
The Micropulse Lidar (MPL) is a ground-based lidar system used for cloud detection. It measures lidar backscatter at 532 nm to retrieve cloud properties, including cloud top and base heights. It can also detect aerosols. MPL has a vertical resolution of 15 m and a maximum range of 18 km. MPL can operate autonomously and typically provides 10-second averaged data.
Earth Science > Spectral/engineering > Lidar > Lidar Depolarization Ratio
The Total Sky Imager (TSI) is a ground-based optical instrument developed by Yankee Environmental Systems (YES), Inc. TSI provides full-color, hemispheric images of the sky during daylight hours using a charge-coupled device (CCD) imager. It also measures fractional sky cover and sun obscuration caused by clouds. TSI can be mounted on mobile platforms such as trailers and research vehicles, enabling it to collect cloud cover data at different locations during field studies.
Sunphotometers are passive optical sensors that measure the amount of sunlight. They are pointed directly at the sun to measure direct sunlight, not sunlight scattered by aerosols. These measurements can be used to determine aerosol optical depth by applying Beer’s Law. Sunphotometers have been deployed on aircraft, research vessels, and field sites for aerosol research and monitoring.
The Multifilter Rotating Shadowband Radiometer (MFRSR) is a ground-based passive radiometer that measures the global and diffuse components of solar irradiance. It measures solar irradiance across six narrowband channels and one broadband channel. The nominal wavelengths of the narrowband channels are 415, 500, 615, 673, 870, and 940 nm. MFRSR typically samples every 20 seconds and takes measurements at four shadowband positions: nadir, first side-band, sun-blocked, and second side-band. MFRSR is deployed at several of the Department of Energy’s Atmospheric Radiation Measurement (ARM) User Facility sites.
