Radar Definition Experiment

The Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR) is an airborne imaging radiometer designed to validate the Special Sensor Microwave Imager/Sounder (SSMIS) instrument. CoSMIR operates across nine spectral channels in the 50-183 GHz range to measure microwave brightness temperature. It has a surface footprint resolution of 1.4 km by 1.4 km at an altitude of 20 km at nadir. CoSMIR can perform both conical and cross-tracking scanning.

The Cloud Radar System (CRS) is an airborne W-band (94 GHz) polarimetric Doppler radar designed for the NASA ER-2 aircraft. CRS provides radar observations of clouds and precipitation from the surface to the lower stratosphere. It has a horizontal resolution of 150 m and a horizontal sampling interval of 50 m. Its vertical resolution is 100 m with a vertical sampling interval of 37.5 m.

The ER-2 X-Band Doppler Radar (EXRAD) is a dual-beam, X-band radar mounted on NASA’s ER-2 aircraft. It was initially intended to be used on the Global Hawk but was instead developed for the ER-2 to replace the ER-2 Doppler Radar (EDOP). EXRAD measures backscatter to determine radar reflectivity, Doppler velocity, and linear depolarization ratio. These measurements help to analyze the phase, orientation, size, and other properties of precipitation particles. EXRAD operates at 9.6 GHz and has a range resolution between 37.5 and 300 meters. It has a swath width of 28 km at an altitude of 20 km during scanning mode, with a typical sampling frequency of 0.25 seconds.

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).

The High-Altitude Wind and Rain Airborne Profiler (HIWRAP) is an airborne Ka- and Ku-band, dual-beam Doppler radar system. It measures radar reflectivity and 3-D wind fields within clouds and precipitation, making it ideal for research missions into hurricanes and severe storms. It was designed to operate at higher altitudes (~ 20 km) than previous airborne wind profilers, allowing for a better vertical profile of the troposphere. HIWRAP has a range resolution of 150 m and operates at the following frequencies: 13.5 GHz, 13.9 GHz, 33.7 GHz, and 35.6 GHz.

The Cloud Radar System (CRS) is an airborne W-band (94 GHz) polarimetric Doppler radar designed for the NASA ER-2 aircraft. CRS provides radar observations of clouds and precipitation from the surface to the lower stratosphere. It has a horizontal resolution of 150 m and a horizontal sampling interval of 50 m. Its vertical resolution is 100 m with a vertical sampling interval of 37.5 m.

The Airborne Multiangle SpectroPolariMetric Imager (AirMSPI) is a passive remote sensing, airborne pushbroom camera developed by the Jet Propulsion Laboratory (JPL) along with engineers from the University of Arizona and the University of Texas. AirMSPI operates across eight spectral bands (355, 380, 445, 470, 555, 660, 865, 935 nm) to deliver multiangle radiance and linear polarization imagery, which can be used to determine aerosol and cloud microphysical properties. AirMSPI has a spatial resolution ranging from 10 to 25 meters, depending on the scan mode, and typically captures images at a rate of 23 Hz. It was designed to be mounted on the nose of NASA’s ER-2 aircraft and has been used in several aerosol and cloud research missions.

The ER-2 X-Band Doppler Radar (EXRAD) is a dual-beam, X-band radar mounted on NASA’s ER-2 aircraft. It was initially intended to be used on the Global Hawk but was instead developed for the ER-2 to replace the ER-2 Doppler Radar (EDOP). EXRAD measures backscatter to determine radar reflectivity, Doppler velocity, and linear depolarization ratio. These measurements help to analyze the phase, orientation, size, and other properties of precipitation particles. EXRAD operates at 9.6 GHz and has a range resolution between 37.5 and 300 meters. It has a swath width of 28 km at an altitude of 20 km during scanning mode, with a typical sampling frequency of 0.25 seconds.

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).

The High-Altitude Wind and Rain Airborne Profiler (HIWRAP) is an airborne Ka- and Ku-band, dual-beam Doppler radar system. It measures radar reflectivity and 3-D wind fields within clouds and precipitation, making it ideal for research missions into hurricanes and severe storms. It was designed to operate at higher altitudes (~ 20 km) than previous airborne wind profilers, allowing for a better vertical profile of the troposphere. HIWRAP has a range resolution of 150 m and operates at the following frequencies: 13.5 GHz, 13.9 GHz, 33.7 GHz, and 35.6 GHz.

The Cloud Physics Lidar (CPL) is an airborne lidar system designed specifically to provide multi-wavelength measurements of cirrus clouds, sub-visual cirrus clouds, and 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 Enhanced MODIS Airborne Simulator (eMAS) is an airborne cross-track scanning spectrometer operated by the Airborne Sensor Facility (ASF) at NASA Ames Research Center. eMAS captures high-resolution imagery of cloud and surface features, which can be used to develop and test algorithms for MODIS satellite observations. It operates across 38 spectral channels covering wavelengths from 0.445 to 14.1 µm and has a scan rate of 6.25 Hz. eMAS offers a spatial resolution of 50 meters and a swath width of 37.25 kilometers at an altitude of 20 kilometers.

The Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR) is an airborne imaging radiometer designed to validate the Special Sensor Microwave Imager/Sounder (SSMIS) instrument. CoSMIR operates across nine spectral channels in the 50-183 GHz range to measure microwave brightness temperature. It has a surface footprint resolution of 1.4 km by 1.4 km at an altitude of 20 km at nadir. CoSMIR can perform both conical and cross-tracking scanning.

The Airborne Third Generation Precipitation Radar (APR-3) is an airborne Doppler dual-polarization radar. It measures Doppler velocity and radar reflectivity at three frequencies: 13.4 GHz, 35.6 GHz, and 94 GHz. These measurements are used to determine the vertical structures of clouds and precipitation characteristics. APR-3 has a horizontal resolution of 700-800 meters at an altitude of 10 km and a vertical resolution of 60 meters. It was developed by NASA's Jet Propulsion Laboratory (JPL) and replaced the APR-2.

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.