FAAM Airborne Laboratory
Facility for Airborne Atmospheric Measurements Airborne Laboratory

The Shortwave Spectroradiometer (SWS) is a radiometer that measures absolute visible and near-infrared spectral radiance. It includes two Zeiss spectroradiometers to measure spectral radiance, which are used to determine cloud optical depth, particle size, and water path. One spectroradiometer operates in the 300-1100 nm wavelength range at a spectral resolution of 8 nm, while the other operates in the 900-2200 nm range at a resolution of 12 nm. SWS has a sampling frequency of 1 Hz. The Department of Energy’s Atmospheric Radiation Measurement (ARM) User Facility operated a ground-based SWS, and the Facility for Airborne Atmospheric Measurements (FAAM) operated an airborne version as part of the airborne laboratory.

The Microwave Airborne Radiometer Scanning System (MARSS) is a passive, along-track scanning microwave radiometer developed by the United Kingdom Met Office and Laboratoire de Me´te´orologie Dynamique du Centre Nationale de Recherche Scientifique (LMD CNRS). It measures brightness temperature across five channels, two at 89 and 157 GHz and three channels centered at the water vapor absorption line at 183 GHz. It is typically used for the calibration and validation of satellite observations. MARSS has a 3-second scan time and an accuracy of better than 1 K.

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-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-Micophysics Probes (Gen-Microphysics) refer to non-specific cloud probes on a platform used to measure cloud microphysics. These are typically in situ probes that measure the physical properties of clouds. These measurements can include particle size distribution, droplet growth, cloud optical thickness, liquid water content, droplet concentration, and cloud condensation nuclei.

The Dual-frequency Extension to In-flight Microwave Observing System (Deimos) is an airborne passive microwave radiometer developed by the UK Met Office. It measures brightness temperature at 23.8 and 50.1 GHz to study clouds, precipitation, and various surfaces, including sea, land, and ice. It has a scan period of 3 seconds and a half-power beamwidth of 10 degrees. Deimos is typically used on the FAAM Airborne Laboratory, alongside the Microwave Airborne Radiometer Scanning System (MARSS).

The Fourier Transformation Spectrometer (FTS) is a high-resolution spectrometer used both in airborne and ground-based applications. FTS measures the solar radiance reflected from the surface, which can be used to estimate levels of carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) in the atmosphere. It offers a spatial resolution of approximately 100m by 1000m and operates at a measurement frequency of 1 Hz during typical research flights.