The TExas and FLorida UNderflights Experiment (TEFLUN) was a NASA-led project that provided ground validation measurements for the Tropical Rain Measuring Mission (TRMM). TEFLUN had two deployments, often referred to as TEFLUN-A and TEFLUN-B. TEFLUN-A took place in April and May of 1998 near and along areas of the Texas coast. NASA’s ER-2 and SPEC Inc.’s Learjet collected airborne measurements, while ground instrumentation provided ground truth data for validation. TEFLUN-B occurred in August and September of the same year in areas near and along the Florida coast. A similar sampling strategy was used, with NASA’s ER-2, DC-8, and the University of North Dakota’s Citation aircraft providing airborne measurements along with ground instrumentation for validation. TEFLUN-B was also carried out in close coordination with NASA’s CAMEX-3 project.
The X-Band Polarimetric Doppler Weather Radar (XPOL) is a ground-based, transportable polarimetric radar manufactured by ProSensing. XPOL measures reflectivity, Doppler velocity, and polarimetric radar parameters to characterize precipitation and clouds. XPOL operates at a 9.41 GHz frequency and has a typical beam width of 1.4 degrees. It has a selectable range resolution of 15-150 meters.
The Ultra-High Frequency (UHF) Wind Profiler is a ground-based Doppler radar. It measures electromagnetic signals to detect wind speed and direction. UHF Wind Profilers operate at the 300-1000 MHz frequency range. Due to operating at a high frequency, they allow for high-resolution wind measurements within the boundary layer.
S-band radars are ground-based or shipborne radars that operate at the frequency range of 2-4 GHz. They provide measurements of radar reflectivity, Doppler velocity, and other radar parameters to characterize precipitation and clouds. They are not easily attenuated making them useful for near and far-range weather observations.
The ER-2 Doppler Radar (EDOP) is an airborne X-band radar designed to operate on the nose of the ER-2 aircraft. It measures radar reflectivity, Doppler velocity, and spectrum width to characterize precipitation systems. EDOP operates at a 9.6 GHz frequency and provides data at a rate of 2 Hz. It has a typical gate spacing of 75 m and a beamwidth of 2.9 degrees. EDOP has been replaced by the EXRAD radar.
The NPOESS Aircraft Sounder Testbed - Microwave (NAST-M) is an airborne microwave radiometer operated by the Massachusetts Institute of Technology (MIT). It measures brightness temperature, which can be used to retrieve water vapor profiles in the atmosphere. It consists of two radiometers: one operating across eight channels between 50-57 GHz and the other across nine at 118 GHz. In 2003, NAST-M was upgraded with two additional radiometers at 183 and 425 GHz to enhance water vapor retrievals and detect small hydrometeors. NAST-M has a spatial resolution of 2.6 km and a cross-track swath width of 100 km at a flight altitude of 20 km. Its typical integration time is 100 ms.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Temperature
The Multispectral Atmospheric Mapping Sounder (MAMS) is an airborne multispectral scanner developed by modifying NASA’s Thematic Mapping Sensor (TMS). MAMS captures reflected radiances in eight visible/near-infrared (VNIR) bands and thermal emissions in four infrared bands. It was built to study weather-related phenomena such as storm system structure, cloud-top temperature, and upper atmospheric water vapor. MAMS operates within the 0.42-12.56 μm spectral range over 12 channels. It has a horizontal resolution of 100 meters and a swath width of approximately 37 kilometers at a flight altitude of 20 kilometers. MAMS scans at a rate of 6.25 Hz.
The Lightning Instrument Package (LIP) is an in situ airborne system that detects electric fields. LIP uses eight electric field mills and a conductivity probe to measure the three-dimensional components of electric fields in thunderstorms around it. LIP has a sampling frequency of 0.02 seconds and an accuracy of 2.5%.
Earth Science > Atmosphere > Atmospheric Electricity > Electric Field
The Submillimeter Limb Sounder (SLS) was a passive heterodyne radiometer designed for high-altitude balloons and aircraft. It measured thermal emission spectra around 640 GHz to detect chlorine monoxide (ClO), hydrogen chloride (HCl), and ozone (O3), and at 604 GHz for nitric acid (HNO3) and nitrous oxide (N2O). It had a field of view of 0.3 degrees, resulting in a vertical resolution of 1.5 km at an altitude of 25 km. SLS completed a full scan in approximately 300 seconds.
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 within the spectral range of 3.7-16.1 µm and has a spectral resolution of 0.25 cm-1. It features 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
The Advanced Microwave Precipitation Radiometer (AMPR) is an airborne passive microwave radiometer. AMPR provides calibrated brightness temperatures, which can be used to determine cloud and precipitation characteristics. It operates across four microwave channels: 10.7, 19.35, 37.1, and 85.5 GHz. These frequencies are sensitive to precipitation, making AMPR well-suited for studying rain events. It has a surface footprint size ranging from 640 m (85.5 GHz) to 2.8 km (10.7 GHz).
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
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 Millimeter-wave Imaging Radiometer (MIR) was a passive airborne cross-track scanning radiometer developed by NASA. MIR measured brightness temperature across nine channels and was used for studying clouds, precipitation, and atmospheric water vapor. MIR operated near and around the following frequencies: 89, 150, 183, 220, and 325 GHz. It had an angular swath of 100 degrees and a sampling interval of 3 seconds. MIR usually operated on NASA ER-2 aircraft before being retired.
Earth Science > Spectral/engineering > Infrared Wavelengths > Brightness Temperature
Earth Science > Atmosphere > Precipitation
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
Earth Science > Atmosphere > Clouds
Earth Science > Atmosphere > Atmospheric Water Vapor
Dropsondes, also known as dropwindsondes, are in situ instruments designed to be released from aircraft. They are equipped with Global Positioning System (GPS) receivers and sensors to collect profile measurements of pressure, temperature, humidity, wind speed, and wind direction. Dropsondes are important during field investigations because they enable researchers to collect vertical profiles in remote locations and during severe weather conditions. Typically, dropsondes have a vertical resolution of 5 meters and provide wind speed and direction measurements every 0.25 seconds, while temperature, pressure, and humidity are recorded every 0.5 seconds.
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
The Cloud Particle Imager (CPI) is an airborne imager developed by SPEC Inc. CPI captures high-resolution (2.3 μm pixel size) images of cloud particles that pass through its sampling volume. It uses a charge-coupled device (CCD) camera operating at 810 nm to record images and can capture up to 74 frames per second with a refresh rate of 40 Hz. The images from CPI can be used to determine microphysical properties such as particle size and shape.
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.
The Rosemount Icing Detector (RICE) is an in-situ airborne probe developed by Rosemount Inc. It uses magnetostrictive oscillation to detect shifts in frequency caused by ice accumulation on the sensing cylinder. These frequency changes correlate with the rate of ice buildup, which helps determine liquid water content. RICE typically samples every second.
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 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 High Volume Precipitation Spectrometer (HVPS) is an in situ airborne particle imager manufactured by SPEC Inc. It uses a 128-photodiode array to capture images of precipitation particles. These images can be used to determine the particles' shape, size, and concentration. HVPS-3 has a pixel resolution of 150 μm and a maximum field of view of 1.92 cm.
The Next Generation Weather Radar (NEXRAD) is a network of high-resolution, S-band radars operated by the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the United States Air Force. NEXRAD measures the magnitude of the returned energy to provide reflectivity, velocity, and spectrum width observations, which can be processed to create mosaic maps of precipitation. NEXRAD radars typically operate with a 0.9-degree beamwidth, 0.25 to 1 km spatial resolution, and a maximum range of 230 to 460 km. Currently, over 160 NEXRAD radars are operating across the United States and some overseas locations.
The Cloud and Aerosol Particle Characterization (CAPAC) is an in situ airborne instrument package that measures cloud and aerosol particle properties. It includes three instruments: a Forward Scattering Spectrometer Probe model 300 (FSSP-300), a Two-Dimensional Optical Array Probe (2D-P), and a CAPAC video camera. It measures particle size from 0.3 micrometers to 6.4 millimeters and shape for particles between 40 micrometers and 6.4 millimeters in diameter. These measurements are used to determine particle size distribution, surface area, and water content in both ice and liquid form. CAPAC has a spatial resolution of 2 km at an aircraft speed of 200 m/sec and a temporal resolution of 0.1 Hz.
The Multicenter Airborne Coherent Atmospheric Wind Sensor (MACAWS) is an airborne lidar system developed by NASA Marshall Flight Center (MSFC), NOAA Environmental Technology Laboratory (ETL), and the Jet Propulsion Laboratory (JPL). It measures lidar backscatter to determine vertical wind profiles, two-dimensional wind fields, and aerosol backscatter in both clear and cloudy conditions. It operates at a nominal wavelength of 10.6 μm with a line-of-sight resolution of 300 meters. It has a coverage range of 10 to 30 km and can achieve a vertical resolution of up to 12.5 km.
Earth Science > Atmosphere > Atmospheric Winds > Wind Profiles > Line Of Sight Winds
The Lidar Atmospheric Sensing Experiment (LASE) is an airborne lidar system developed at NASA's Langley Research Center (LaRC). LASE uses the differential absorption lidar technique to provide profile measurements of water vapor and aerosols in the atmosphere. LASE operates at the 815 nm wavelength and has a measurement frequency of 5 Hz. For aerosol scattering profiles, LASE has a horizontal resolution of 200 m and a vertical resolution of 30 m. It has a horizontal resolution of 5 km and a vertical resolution of 0.2 km for water vapor measurements.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
Dropsondes, also known as dropwindsondes, are in situ instruments designed to be released from aircraft. They are equipped with Global Positioning System (GPS) receivers and sensors to collect profile measurements of pressure, temperature, humidity, wind speed, and wind direction. Dropsondes are important during field investigations because they enable researchers to collect vertical profiles in remote locations and during severe weather conditions. Typically, dropsondes have a vertical resolution of 5 meters and provide wind speed and direction measurements every 0.25 seconds, while temperature, pressure, and humidity are recorded every 0.5 seconds.
Earth Science > Atmosphere > Atmospheric Temperature
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 Lightning Instrument Package (LIP) is an in situ airborne system that detects electric fields. LIP uses eight electric field mills and a conductivity probe to measure the three-dimensional components of electric fields in thunderstorms around it. LIP has a sampling frequency of 0.02 seconds and an accuracy of 2.5%.
Earth Science > Atmosphere > Atmospheric Electricity > Electric Field
The Polarimetric Scanning Radiometer (PSR) is an airborne passive microwave imaging radiometer developed by Georgia Tech and NOAA. It captures polarimetric microwave emission images of Earth to analyze ocean and land surface features, precipitation, ice, and clouds. PSR operates across four microwave channels: 10.7 GHz, 18.7 GHz, 37 GHz, and 89 GHz. The PSR/A version includes an extra dual-polarimetric channel at 21.5 GHz. Operating at an altitude of 22,000 feet above sea level, PSR has a spatial resolution ranging from 0.3 to 2.2 km, depending on the frequency band and scan mode.
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
The Airborne Vertical Atmospheric Profiling System (AVAPS) is an airborne system that uses dropsondes and Global Positioning System (GPS) receivers to gather in situ profiles of atmospheric parameters. It provides profile measurements of temperature, pressure, and humidity every 0.5 seconds, and atmospheric wind measurements every 0.25 seconds. AVAPS has a vertical resolution of approximately 10 meters and can launch dropsondes every 20 seconds. Developed by the National Center for Atmospheric Research (NCAR) for the NASA Global Hawk, it can also be deployed on other aircraft such as the DC-8 and P-3.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
Earth Science > Atmosphere > Atmospheric Temperature
The Airborne Multichannel Microwave Radiometer (AMMR) was a passive, remote airborne microwave radiometer. It measured thermal microwave emissions in terms of brightness temperature. AMMR consisted of an array of radiometers operating at the following frequencies: 10, 18.7, 21, 37, and 92 GHz. It had a typical sampling rate of 1 second and a spatial resolution of 1-2 km at the surface.
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
The Airborne Rain Mapping Radar (ARMAR) is an airborne Ku-band Doppler radar developed by the Jet Propulsion Laboratory (JPL). It was designed to simulate the Tropical Rainfall Measuring Mission (TRMM) satellite mission for algorithm development and calibration. ARMAR operates at 13.8 GHz to measure the return power of microwave energy, which is used to determine velocity and reflectivity. It can also serve as a radiometer to measure brightness temperature. ARMAR typically scans across the track at 20-degree angles but can operate at a fixed angle. It has a horizontal resolution of 800 m and a swath width of 9 km at a flight altitude of 12 km.
The Diode Laser Hygrometer (DLH) is an in situ airborne hygrometer developed by NASA’s Langley Research Center (LaRC). It uses tunable diode laser absorption to detect water vapor in the atmosphere. DLH operates in the near-infrared range at about 1.4 μm and has a measurement frequency of 100 Hz. It can deliver precise measurements of water vapor even when flying through clouds.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity > Relative Humidity
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
The JPL Surface Acoustic Wave (SAW) Hygrometer is an in situ airborne microhygrometer developed by the Jet Propulsion Laboratory (JPL). It uses a SAW device to detect condensation for dewpoint or frostpoint temperature measurements. The JPL SAW hygrometer is two orders of magnitude more sensitive to condensation compared to chilled-mirror hygrometers, allowing for a faster response to humidity changes. JPL SAW Hygrometer has a temporal resolution of up to 0.1 seconds.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Temperature > Upper Air Temperature > Dew Point Temperature
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Dew Point Temperature
The S-band Polarimetric (S-POL) Doppler radar is a ground-based transportable radar operated by the National Center for Atmospheric Research (NCAR). It is a dual-polarization radar that provides radar measurements to characterize precipitation and convective systems. S-Pol operates at 2.7-2.9 GHz frequency and has a beam width of 0.92 degrees. S-Pol has a range of 150-675 m and a gate spacing of 37.5-150 m.
The Ultra-High Frequency (UHF) Wind Profiler is a ground-based Doppler radar. It measures electromagnetic signals to detect wind speed and direction. UHF Wind Profilers operate at the 300-1000 MHz frequency range. Due to operating at a high frequency, they allow for high-resolution wind measurements within the boundary layer.
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
The Cloud Particle Imager (CPI) is an airborne imager developed by SPEC Inc. CPI captures high-resolution (2.3 μm pixel size) images of cloud particles that pass through its sampling volume. It uses a charge-coupled device (CCD) camera operating at 810 nm to record images and can capture up to 74 frames per second with a refresh rate of 40 Hz. The images from CPI can be used to determine microphysical properties such as particle size and shape.
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.
The Rosemount Icing Detector (RICE) is an in-situ airborne probe developed by Rosemount Inc. It uses magnetostrictive oscillation to detect shifts in frequency caused by ice accumulation on the sensing cylinder. These frequency changes correlate with the rate of ice buildup, which helps determine liquid water content. RICE typically samples every second.
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 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 High Volume Precipitation Spectrometer (HVPS) is an in situ airborne particle imager manufactured by SPEC Inc. It uses a 128-photodiode array to capture images of precipitation particles. These images can be used to determine the particles' shape, size, and concentration. HVPS-3 has a pixel resolution of 150 μm and a maximum field of view of 1.92 cm.
