Cirrus Regional Study of Tropical Anvils and Cirrus Layers Florida Area Cirrus Experiment

The Cloud Particle Imager (CPI) is an airborne imager manufactured by SPEC Inc. CPI collects high-resolution (2.3 μm pixel size) images of cloud particles that pass through its sample volume. It uses a charge-coupled device (CCD) camera that operates at 810 nm to record images and can take up to 74 frames per second with a refresh rate of 40 Hz. The imagery from CPI can be used to derive microphysical properties such as particle size and habit.

The Counterflow Virtual Impactor (CVI) is an in situ airborne instrument that samples cloud droplets. It samples cloud droplets by removing them from the surrounding air through inertial impaction. CVI is typically deployed with additional sensors to provide measurements of cloud particle concentration, cloud liquid water, and water vapor of the sample droplets. CVI can detect cloud droplets as small as 7 microns in diameter and has a typical time response of 1 second.

The High Volume Particle Sampler, also known as the High Volume Precipitation Spectrometer (HVPS), measures particle size distributions and obtains particle images in the size range of about 0.1 cm to 6 cm. It is an open-path instrument located on the outside of the aircraft, typically below the wing. A laser sheet throws a shadowgraph image of the hydrometeor (cloud droplets or ice crystals) in the sample volume on a photodiode array. As the hydrometeor moves through the sample volume, this optical array records the moving shape and a two-dimensional picture can be recorded. At an air speed of 100 m/s, the sample volume is 310 l/s. The recorded images can be analyzed for size distributions, number concentrations, and further cloud properties detailed below. Hydrometeors in the range of 0.3−19.2 mm can be fully recorded at a 150 μm resolution; larger particles can only be sized along the direction of flight. In order to keep the pixel resolution along the flight path constant, the system clock frequency is adjusted according to the detected True Air Speed (TAS) by the data system itself. The maximum clock frequency for the HVPS is 240 kHz. The HVPS data recorded during this project has 400 m m resolution along the flight path.

A Tunable Diode Laser Absorption Spectrometer (TDLAS) is an airborne or ground-based in situ optical spectrometer. TDLAS measures the wavelength-dependent absorption of light to determine the concentration of various trace gases. It can also determine the gas species' temperature, pressure, velocity, and mass flux when possible. TDLAS has a typical time resolution of 1 second.

The Forward Scattering Spectrometer Probe (FSSP) is an in situ airborne optical particle counter originally designed by Particle Measuring Systems, Inc. It provides particle size distribution by measuring the intensity of the light scattered by individual particles within the cloud. FSSP can detect particles within a diameter range of 0.5 to 47 μm. It operates at a wavelength of 633 nm and has a typical sampling frequency of 1 Hz.

The 2D-C/P Hydrometeor Imaging Probe (2D-C/P) is an in situ, airborne instrument that captures imagery of hydrometeors. It collects these images by recording the status (illuminated or shadowed) of the photodiode array as the shadow of the hydrometeors passes over. 2D-C/P also provides 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 Continuous Flow Diffusion Chamber (CFDC) is an in situ airborne optical particle counter (OPC). It utilizes vertical flow through two chambers with varying wall temperatures to grow ice particles within an OPC at the bottom of the instrument to determine particle size distribution. If conditions are steady, the CFDC can also measure flow rate, temperature, and humidity. CFDC measures the size distribution of aerosol particles between 0.4 and 20 mm. It measures particle counts every 0.2 seconds and particle spectra every 10 seconds.

The Cloud Integrating Nephelometer (CIN) is an in situ airborne nephelometer developed by Gerber Scientific. It measures the asymmetry parameter, optical extinction coefficient, and extinction-to-backscatter ratio of clouds. It operates at the 635 nm wavelength and can measure cloud particles within the 4-2500 μm size range. CIN has a typical measurement rate of 1 Hz and a measurement accuracy of 2% and 10% for the asymmetry parameter and optical extinction coefficient, respectively.

The Multi-sample Aerosol Collection System (MACS) is an in situ airborne aerosol sampling system. It consists of a two-stage impact collector, which allows for the collection of aerosol particles on electron microscope grids for further analysis. MACS can collect particles as small as 0.02 μm for altitudes up to 60,000 feet. MACS can collect around 24 samples per flight.

The Microwave Temperature Profiler (MTP) is an airborne microwave radiometer developed by the Jet Propulsion Laboratory and later modified by NCAR. It measures thermal emissions from oxygen molecules in the atmosphere to prove temperature profiles above, below, and at flight level. It operates between 55 to 59 GHz and provides profiles every 17 seconds with 4 km horizontal spacing. MTP has a vertical resolution of 150 m near the aircraft.

The Cloud Particle Imager (CPI) is an airborne imager manufactured by SPEC Inc. CPI collects high-resolution (2.3 μm pixel size) images of cloud particles that pass through its sample volume. It uses a charge-coupled device (CCD) camera that operates at 810 nm to record images and can take up to 74 frames per second with a refresh rate of 40 Hz. The imagery from CPI can be used to derive microphysical properties such as particle size and habit.

The NOAA Chemical Ionization Mass Spectrometer (NOAA-CIMS) is an in situ airborne spectrometer developed by NOAA. It was designed to provide high-precision measurements of reactive nitrogen and halogen species such as nitric acid, nitric oxide, and bromine chloride in the upper atmosphere. It can also provide measurements of ozone and water vapor concentrations. NOAA-CIMS has a detection limit of 30 pptv and a temporal resolution of 1 second.

The NOAA Pressure and Temperature (NOAA PT) is an in situ airborne probe that measures atmospheric pressure and temperature. It comprises a digital pressure temperature transducer and slow and fast responding temperature probes. NOAA PT provides measurements of both static and ram pressure and upper air temperature every second. It has an accuracy of 0.5 degrees for temperature and 0.5 mbars for pressure.

This data will be added in future versions

The Video Ice Particle Sampler (VIPS) is an in situ airborne electro-optical instrument. It continuously collects and images cloud particles as small as 3 μm. Cloud particle samples are collected on a looped belt where they are exposed to a high-resolution video camera. Particle imagery is recorded at 30 Hz and has an image resolution of 1.12 μm per pixel. VIPS also provides particle size distribution and concentration.

The Multiple-Angle Aerosol Spectrometer Probe (MASP) is an in situ airborne spectrometer. It measures the light intensity of scatter aerosol particles at 780 nm wavelength across multiple angles to determine particle size and concentration. It can detect particles within the 0.3 to 20 micron size range. MASP typically has a time resolution of 10 seconds.

The Cloud Aerosol and Precipitation Spectrometer (CAPS) is an in situ airborne spectrometer manufactured by Droplet Measurement Technologies. It combines the Cloud Imaging Probe (CIP), the Cloud and Aerosol Spectrometer (CAS), and the Hotwire Liquid Water Content (LWC) Sensor into one instrument. CAPS measures the size distribution of aerosol, cloud, and liquid droplets for particles between the sizes of 50-1600 μm at a time resolution of 1 Hz. It can also record images of cloud particles and provide measurements of temperature, pressure, and LWC.

The Particle Analysis by Laser Mass Spectrometry (PALMS) is a laser ionization mass spectrometer owned and operated by NOAA. PALMS provides in situ measurements of aerosol particles and their chemical composition by using a pulse from a UV laser (193 nm) to generate ions. These ions are then analyzed with a time-of-flight mass spectrometer to provide the mass spectrum of each particle which can be used to classify the individual aerosol particles. PALMS has an aerosol size range of 0.2 to 3 microns and has a typical data rate of around 1 to 10 Hz. It can be utilized for either airborne or laboratory measurements of aerosols.

Argus is a two-channel, tunable diode laser instrument that was developed at NASA Ames Research Center. Argus collects in situ measurements of carbon monoxide (CO), nitrous oxide (N2O), and methane (CH4) in the atmosphere by using second harmonic spectroscopy. Argus operates in the mid-infrared range (3.3 and 4.7 micrometers) and has an accuracy of about 3% for data rates of 0.1 to 0.5 Hz. Argus is ideal for small payload platforms such as balloons and uncrewed aerial vehicles (UAV) due to its lightweight and compact design.

The Solar Spectral Flux Radiometer (SSFR) is an airborne radiometer developed by the Ames Atmospheric Radiation Group. It provides remotely sensed measurements of solar spectral irradiance in the troposphere. SSFR operates across the 300-2150 nm wavelength range and has a spectral resolution of 8-12 nm. It has a typical data collection rate of 1 Hz and has a radiometric accuracy of 3%.

The High-Sensitivity Fast-Response CO2 Analyzer (Harvard CO2) is an in situ airborne spectrometer operated by Harvard University. It measures carbon dioxide (CO2) concentrations using a modified nondispersive infrared CO2 analyzer. CO2 mixing ratios are determined by measuring absorption at 4.26 μm. Harvard CO2 has a measurement sampling rate of 0.5 Hz and a precision of 0.05 ppm. Harvard is typically deployed on high-altitude aircraft like the ER-2, but it has been used for balloon-borne measurements.

The High Volume Particle Sampler, also known as the High Volume Precipitation Spectrometer (HVPS), measures particle size distributions and obtains particle images in the size range of about 0.1 cm to 6 cm. It is an open-path instrument located on the outside of the aircraft, typically below the wing. A laser sheet throws a shadowgraph image of the hydrometeor (cloud droplets or ice crystals) in the sample volume on a photodiode array. As the hydrometeor moves through the sample volume, this optical array records the moving shape and a two-dimensional picture can be recorded. At an air speed of 100 m/s, the sample volume is 310 l/s. The recorded images can be analyzed for size distributions, number concentrations, and further cloud properties detailed below. Hydrometeors in the range of 0.3−19.2 mm can be fully recorded at a 150 μm resolution; larger particles can only be sized along the direction of flight. In order to keep the pixel resolution along the flight path constant, the system clock frequency is adjusted according to the detected True Air Speed (TAS) by the data system itself. The maximum clock frequency for the HVPS is 240 kHz. The HVPS data recorded during this project has 400 m m resolution along the flight path.

The Closed-path Laser Hygrometer (CLH) is a tunable diode laser hygrometer that was developed by the University of Colorado along with the Jet Propulsion Laboratory (JPL). The CLH measures water vapor via second-harmonic absorption spectroscopy. It provides measurements approximately every 1.5 seconds and operates at the 1.37 μm wavelength.

The NOAA Dual-Beam UV-Absorption Ozone Photometer (NOAA-O3) is an in situ optical balloon-borne and airborne instrument that measures ozone concentrations in the troposphere and lower stratosphere. It operates at the 254 nm wavelength allowing it to calculate the ozone number density due to the accurate ozone absorption cross section at that wavelength. It has a sampling rate of 2 Hz and a horizontal resolution of 100 to 200 meters at typical research flight speeds.

The Aircraft Laser Infrared Absorption Spectrometer (ALIAS) is a high-resolution spectrometer developed by the Jet Propulsion Laboratory (JPL) to fly aboard the NASA ER-2. ALIAS takes real-time measurements of various nitrogen, carbon, and hydrogen compounds, including NO2, CH4, and HCl. Its ability to be flown at high altitudes paired with its fast sample rate makes the ALIAS an ideal instrument to study atmospheric chemistry processes within polar stratospheric clouds (PSCs).

The Nucleation-mode Aerosol Size Spectrometer (NMASS) is an airborne, in situ spectrometer used to measure particle size distribution and cloud condensation nuclei (CCN). NMASS consists of 5 parallel condensation nucleus counters (CNCs) that are used to sample particles within the 3 to 60 nm diameter range. It can be equipped on multiple types of aircraft and is ideal for sampling cirrus clouds in the upper atmosphere. NMASS provides fast time response measurements at a temporal resolution of 10 Hz.

The Focused Cavity Aerosol Spectrometer (FCAS) is an in situ airborne optical particle counter designed by Particle Measuring Systems, Inc. FCAS measures the light scattered by the individual aerosol particles to determine the particle size distribution. It can detect aerosol particles in the size range of 0.06 to 2 μm and can operate at altitudes up to 20 km. Typically, FCAS provides measurements at a sampling rate of 10 seconds.

The Forward Scattering Spectrometer Probe (FSSP) is an in situ airborne optical particle counter originally designed by Particle Measuring Systems, Inc. It provides particle size distribution by measuring the intensity of the light scattered by individual particles within the cloud. FSSP can detect particles within a diameter range of 0.5 to 47 μm. It operates at a wavelength of 633 nm and has a typical sampling frequency of 1 Hz.

Harvard Water Vapor (HWV) is an in situ airborne hygrometer developed at Harvard University that measures water vapor mixing ratios in the upper troposphere and lower stratosphere. HWV consists of two instruments with distinctly different methods for detecting water vapor: the Lyman-α photo-fragment fluorescence instrument (LyA) and a tunable diode laser direct absorption instrument (HHH -Harvard Herriott Hygrometer). By combining both instruments, HWV can identify and limit systematic errors while in flight. It provides measurements of water vapor mixing ratio from 1 to 1000 ppmv at a frequency of 1 Hz and with an accuracy of 5%.

The JPL Laser Hygrometer (JLH) is an in situ airborne hygrometer developed at the Jet Propulsion Laboratory (JPL). It uses a tunable diode laser that operates at 1.37 μm to measure atmospheric water vapor in the upper troposphere and lower stratosphere. JLH has a minimum spatial resolution of 25 m and a detection range of 1 to 500 ppmv. It has a typical sampling rate of 1 Hz and can provide measurements at a precision of 0.05 ppmv.

NOx/NOxy is an in situ chemiluminescence instrument. It provides measurements of nitrogen oxides and ozone in the atmosphere at a spatial resolution better than 100m for typical DC-8 research flight speeds. NOx/NOxy can be utilized on ground-based, airborne, and shipborne platforms allowing it to be used in various types of atmospheric chemistry and air quality studies.

The Meteorological Measurement System (MMS) is an in situ airborne instrument used for measuring atmospheric state parameters. MMS provides high-resolution and accurate measurements of atmospheric pressure, temperature, and wind direction/speed immediately around the plane. Additional parameters can be derived such as potential temperature, true airspeed, turbulence dissipation rate, and Reynolds number. Measurements of all parameters are typically collected at a rate of 20 Hz.

The Cloud Integrating Nephelometer (CIN) is an in situ airborne nephelometer developed by Gerber Scientific. It measures the asymmetry parameter, optical extinction coefficient, and extinction-to-backscatter ratio of clouds. It operates at the 635 nm wavelength and can measure cloud particles within the 4-2500 μm size range. CIN has a typical measurement rate of 1 Hz and a measurement accuracy of 2% and 10% for the asymmetry parameter and optical extinction coefficient, respectively.

The Cloud Radar System (CRS) is an airborne W-band polarimetric Doppler radar. CRS provides radar observations of clouds and precipitation from the surface up to the lower stratosphere. It has an operating frequency of 94 GHz and has a 150m range resolution. CRS has a typical vertical resolution of 100m and a gate spacing of 37.5m.

A dropsondes or 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 direction. Dropsondes are important during field investigations because they allow researchers to collect vertical profiles in remote locations and during severe weather events. Dropsondes typically have a vertical resolution of 5 m and provide measurements of wind speed/direction every 0.25 seconds and temperature, pressure, and humidity every 0.5 seconds.

The Meteorological Measurement System (MMS) is an in situ airborne instrument used for measuring atmospheric state parameters. MMS provides high-resolution and accurate measurements of atmospheric pressure, temperature, and wind direction/speed immediately around the plane. Additional parameters can be derived such as potential temperature, true airspeed, turbulence dissipation rate, and Reynolds number. Measurements of all parameters are typically collected at a rate of 20 Hz.

The JPL Laser Hygrometer (JLH) is an in situ airborne hygrometer developed at the Jet Propulsion Laboratory (JPL). It uses a tunable diode laser that operates at 1.37 μm to measure atmospheric water vapor in the upper troposphere and lower stratosphere. JLH has a minimum spatial resolution of 25 m and a detection range of 1 to 500 ppmv. It has a typical sampling rate of 1 Hz and can provide measurements at a precision of 0.05 ppmv.

The MODIS Airborne Simulator (MAS) is an airborne multispectral spectrometer designed to simulate the satellite instrument Moderate-Resolution Imaging Spectrometer (MODIS). MAS operates across 50 spectral channels in the 0.55 to 14.2 μm range to provide high-resolution imagery of clouds and surface features. MAS has a horizontal spatial resolution of 50 m and a swath width of about 36 km at an altitude of 20 km at nadir. It has a scan rate of 6.25 Hz with each scan line containing 716 pixels.

The Microwave Temperature Profiler (MTP) is an airborne microwave radiometer developed by the Jet Propulsion Laboratory and later modified by NCAR. It measures thermal emissions from oxygen molecules in the atmosphere to prove temperature profiles above, below, and at flight level. It operates between 55 to 59 GHz and provides profiles every 17 seconds with 4 km horizontal spacing. MTP has a vertical resolution of 150 m near the aircraft.

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 across three wavelengths: 355 nm, 532 nm, and 1064 nm. These measurements can be used to derive 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.

The Solar Spectral Flux Radiometer (SSFR) is an airborne radiometer developed by the Ames Atmospheric Radiation Group. It provides remotely sensed measurements of solar spectral irradiance in the troposphere. SSFR operates across the 300-2150 nm wavelength range and has a spectral resolution of 8-12 nm. It has a typical data collection rate of 1 Hz and has a radiometric accuracy of 3%.

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 Conical Scanning Submillimeter-wave Imaging Radiometer (CoSSIR) is a passive remote imaging radiometer. It has been flown on multiple aircraft since its development, including NASA’s ER-2 aircraft. CoSSIR was designed to take measurements of ice clouds and brightness temperatures. Its measurements can also be used to estimate water vapor profiles and snowfall rates. CoSSIR has a surface footprint of 1.4 km at nadir. It completes a scan cycle every 4.6 seconds. CoSSIR has 12 channels and operates in the 183-874 GHz range.

The Radiation Measurement System (RAMS) is an airborne passive radiometer that measures broadband solar irradiance. RAMS consists of two radiometers: the Total Solar Broadband Radiometer (TSBR) and the Fractional Solar Broadband Radiometer (FSBR). The TSBR operates in the 0.224 to 3.91 μm range while the FSBR operates between 0.68 to 3.3 μm. It has a response time of about 60 msec and can provide measurements about every 5 m for aircraft speeds around 75 m/s. RAMS is typically used for airborne operations, but it can be used to collect ground-based measurements as well.

The Multi-sample Aerosol Collection System (MACS) is an in situ airborne aerosol sampling system. It consists of a two-stage impact collector, which allows for the collection of aerosol particles on electron microscope grids for further analysis. MACS can collect particles as small as 0.02 μm for altitudes up to 60,000 feet. MACS can collect around 24 samples per flight.

Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentration. CPCs measure aerosol concentration by condensing fluid onto the particles, allowing them to grow to more detectable sizes for optical scattering. Typically, CPCs can detect particles with a size range of 7 nm-3 μm, can measure particle concentrations up to 100,000 particles/cc, and can provide measurements at 1-second intervals. CPCs are manufactured by TSI Incorporated and can be deployed on airborne, shipborne, and ground-based platforms.

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.

The Linear Etalon Imaging Spectral Array (LEISA) is an airborne infrared (IR) hyperspectral imager. It is the airborne of the LEISA satellite instrument and is used for calibration and validation. It operates across the 1 to 2.5 microns spectral range to collect IR imagery. It has a spatial resolution of 2 meters at a 1 km altitude and of 20 meters at a 10 km altitude. LEISA has a swath width of approximately 29 degrees.

The Aerosol Mass Spectrometer (AMS) is a spectrometer that measures the chemical composition and properties of sub-micron aerosol particles. AMS has a maximum data collection of 100 Hz and can detect particles with a size range of 40 nm to 1 micron. It operates by switching between mass spectrum (MS) mode and particle time-of-flight (PToF) mode to determine the chemical makeup of aerosol samples. The AMS can be deployed on aircraft, ships, mobile laboratories, or placed directly at a field site.

The Passive-Cavity Aerosol Spectrometer Probe (PCASP) is an in situ airborne optical spectrometer manufactured by Droplet Measurement Technologies. It measures the light scattered by particles to determine the aerosol size distribution and concentration in the 0.1 to 3.0 μm size range. PCASP operates at the 632 nm wavelength and has a typical sampling rate of 10 Hz.

The Cloud Aerosol and Precipitation Spectrometer (CAPS) is an in situ airborne spectrometer manufactured by Droplet Measurement Technologies. It combines the Cloud Imaging Probe (CIP), the Cloud and Aerosol Spectrometer (CAS), and the Hotwire Liquid Water Content (LWC) Sensor into one instrument. CAPS measures the size distribution of aerosol, cloud, and liquid droplets for particles between the sizes of 50-1600 μm at a time resolution of 1 Hz. It can also record images of cloud particles and provide measurements of temperature, pressure, and LWC.

The Microorifice Uniform Deposit Impactor (MOUDI) is an in situ airborne or ground-based sampler developed by the MSP Corporation. It is an eight-stage impactor used for high-accuracy aerosol sampling for gravimetric or chemical analysis. MOUDI has a sample flow rate of 30 liters per minute and can sample particles in the size range of 0.056-18 µm. It is used for applications such as air pollution research, engine emission testing, and aerosol analysis.

Broadband Radiometers (BBR) are modified versions of the Kipp & Zonen CM-22 pyranometers and CG-4 pyrgeometers. They have been modified to be more suitable for airborne platforms through different instrument housing and signal amplification. BBR measures solar irradiance in the 0.2-3.6 μm wavelength range and infrared (IR) irradiance in the 4.5-42 μm range. These measurements can be used to derive net irradiance, radiative forcing, absorption, and albedo. It has a typical sampling rate of 1 Hz and a hemispheric field-of-view.

The Solar Spectral Flux Radiometer (SSFR) is an airborne radiometer developed by the Ames Atmospheric Radiation Group. It provides remotely sensed measurements of solar spectral irradiance in the troposphere. SSFR operates across the 300-2150 nm wavelength range and has a spectral resolution of 8-12 nm. It has a typical data collection rate of 1 Hz and has a radiometric accuracy of 3%.

The Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. APS measures aerodynamic particles in the 0.5-20 μm size range. It also measures the light-scattering intensity of the particles in the 0.37-20 μm optical size range. APS provides particle size distributions for 52 channels at a typical sampling time of 1 second. It uses a laser diode operating at 655 nm and has a size resolution of 0.02 μm at 1 μm. APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is optical method for counting atmospheric aerosol particles.

The Forward Scattering Spectrometer Probe (FSSP) is an in situ airborne optical particle counter originally designed by Particle Measuring Systems, Inc. It provides particle size distribution by measuring the intensity of the light scattered by individual particles within the cloud. FSSP can detect particles within a diameter range of 0.5 to 47 μm. It operates at a wavelength of 633 nm and has a typical sampling frequency of 1 Hz.

The Tandem Differential Mobility Analyzer (TDMA) is an in situ airborne and ground-based analyzer that measures the physical properties of aerosol particles such as size distribution and concentration. It can measure particles in the size range of 0.013 to 0.75 mm at a size resolution of 0.013 mm at 0.2 mm. The TDMA is sometimes combined with an Aerodynamic Particle Sizer (APS) to allow measurements of particles in the submicron range. A typical measurement sequence of TDMA can take approximately 45 minutes to complete.

TSI Particle Probes are in situ particle counters and detectors manufactured by TSI Incorporated. They are used to detect aerosol particles and determine concentration and particle counts. TSI Particle Probes are typically combined with particle sizers, which can measure size distribution. TSI Particle Probes can be deployed on aircraft, research vessels, and ground-based platforms.

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 system that operates at around 35 GHz. MMCR has a beamwidth of 0.2 degrees and typical vertical resolutions of 45 and 90 meters.

The Scanning ARM Cloud Radar (SACR) is a ground-based Doppler radar system operated by the Department of Energy (DoE) Atmospheric Radiation Measurement (ARM) User Facility. It is a polarimetric Doppler radar consisting of three radar designs at different operating frequencies: X-SACR (9.71 GHz), Ka-SACR (35.3 GHz), and W-SACR (94 GHz). For each deployment location, two SACR radars are deployed with operating frequencies determined by atmospheric attenuation at the site. SACR provides measurements of radar reflectivity, Doppler velocity, spectrum width, and other polarimetric parameters at a gate spacing of 25 meters.

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.

This data will be added in future versions

The microwave radiometers (MWRs) are ground-based radiometers manufactured by Radiometrics Corporation and operated by the Atmospheric Radiation Measurement (ARM) Research Facility. MWR measures brightness temperature at 23.8 and 31.4 GHz to derive column-integrated amounts of water vapor and liquid water in the atmosphere. MWR has a field of view (FOV) from about 5.9 to 4.5 degrees depending on the channel and has a typical time resolution of 20 s for sky-view observations.

This data will be added in future versions.

The Precision Radiation Thermometer (PRT-5) is an in situ infrared temperature sensor. It makes non-contact infrared (8-14 μm) temperature measurements between -50 to 150 degrees Celsius with an accuracy of 0.5 degrees Celsius. It has a typical field of view of 2 degrees and a response time of either 0.3 Hz, 3 Hz, or 30 Hz. PRT-5 can be deployed on aircraft, vehicles, research vessels, and other ground-based platforms. It can be used for sea surface, ocean water, cloud, and air temperature measurements.

This data will be added in future versions

Broadband Radiometers (BBR) are modified versions of the Kipp & Zonen CM-22 pyranometers and CG-4 pyrgeometers. They have been modified to be more suitable for airborne platforms through different instrument housing and signal amplification. BBR measures solar irradiance in the 0.2-3.6 μm wavelength range and infrared (IR) irradiance in the 4.5-42 μm range. These measurements can be used to derive net irradiance, radiative forcing, absorption, and albedo. It has a typical sampling rate of 1 Hz and a hemispheric field-of-view.

This data will be added in future versions

The Total Sky Imager (TSI) is a ground-based, optical instrument that is manufactured by Yankee Environmental Systems (YES), Inc. TSI can provide full-color, hemispheric images of the sky during the day by using a charge-coupled device (CCD) imager. It also can provide measurements of fractional sky cover and sun obscuration by cloud. TSI can be mounted on mobile platforms such as trailers and research vehicles, allowing it to collect cloud cover measurements in various locations during a field investigation.

Ceilometers are ground-based, remote-sensing sensors that provide measurements of cloud ceilings and vertical visibility. They use either a laser beam or another light source to detect backscatter of clouds, precipitation, and aerosols. Ceilometers can provide detailed and accurate measurements in all types of weather conditions and have low operating costs. Ceilometers are typically used in boundary layer and cloud research applications.

The NASA S-band Dual Polarimetric Radar (NPOL) is a transportable, ground-based scanning dual polarimetric Doppler radar. As an active remote sensor, NPOL detects returned electromagnetic radiation to identify radar reflectivity, Doppler velocity, rainfall rate, particle size distribution, water contents, and precipitation type. Under typical operating conditions, NPOL has a beamwidth of 0.95° and a 150 km maximum range. NPOL is operationally equivalent to Doppler radars employed by the U.S. National Weather Service’s Next Generation Weather Radar (NEXRAD) network, but NPOL has the added advantage of being fully deployable.

The Multifilter Rotating Shadowband Radiometer (MFRSR) is a ground-based passive radiometer used to measure 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 has a typical sampling interval of 20 seconds and takes measurements at four different shadowband positions: nadir, first side-band, sun-blocked, and second side-band. MFRSR is deployed across several of the Department of Energy’s Atmospheric Radiation Measurement (ARM) User Facility sites.

The Surface-sensing Measurements for Atmospheric Radiative Transfer (SMART) is a ground-based remote instrument suite operated by NASA Goddard Space Flight Center (GSFC). It consists of several remote sensing instruments, such as a micro-pulse lidar, sun photometer, and broadband radiometers housed in a twenty-foot trailer. SMART provides measurements of solar spectral radiance, surface spectral bi-directional reflectance, albedo, and shortwave and longwave irradiance at a spectral resolution of 1 nm. It operates across the ultraviolet to microwave spectral range. SMART is part of the SMARTLabs mobile facilities.

Radiosondes are a balloon-borne instrument package used to collect profile measurements of pressure, temperature, humidity, and winds. These sensors are connected to a radio transmitter that sends the measurements to a ground receiver typically operating in the 400-406 MHz range. They typically provide measurements at 1-6 seconds, depending on the type and manufacturer of the radiosonde. Radiosondes are used for weather forecasting, ground truth satellite data, atmospheric research, and input for weather prediction models.

The ELectra DOppler RAdar (ELDORA) is an airborne radar system developed by the National Center for Atmospheric Research (NCAR) and France's Centre de Recherches en Physique de L'Environnement Terrestre et Planetaire (CRPE). It was designed to operate on the NCAR Electra aircraft, but it also operates on the Naval Research Lab (NRL) P-3 aircraft. It is an X-band (9.3-9.8 GHz) radar that measures radar reflectivity, Doppler velocity, and other radar parameters to characterize convective systems and clouds. ELDORA has a beamwidth of 1.8 degrees and a range resolution of 37.5 to 1200 meters, depending on radar configuration.

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.

The NPOESS Aircraft Sounder Testbed - Microwave (NAST-M) is an airborne microwave radiometer maintained 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 with one operating across 8 channels between 50-57 GHz and the other operating across 9 channels at 118 GHz. In 2003, NAST-M was upgraded with two additional radiometers operating at 183 and 425 GHz to improve water vapor retrievals and the detection of 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. It has a typical integration time of 100 ms.

The Research Scanning Polarimeter (RSP) is an airborne, passive polarimeter developed by SpecTIR Corporation. It measures total radiance and linear polarization across 9 spectral bands in the visible and infrared wavelengths (410-2250 nm). These measurements can be used to derive aerosol and cloud properties. RSP has a time resolution of 0.8 seconds, a field of view of 14 mrad, and a horizontal resolution of about 100 m at an altitude of 5 km.

The NPOESS Aircraft Sounder Testbed - Interferometer (NAST-I) is an airborne infrared interferometer maintained and operated by NASA Langley Research Center (LaRC). It uses Fourier transform spectroscopy to provide measurements of 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 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 period for NAST-I takes around 12.2 seconds.

The Far Infrared Sensor for Cirrus (FIRSC) is a remote passive airborne infrared spectrometer. It uses Fourier transform spectroscopy (FTS) to measure the infrared radiance of cirrus clouds. FIRSC operates across two channels with a wavenumber range of 10-35 per centimeter and 80-135 per centimeter. FIRSC has a field of view of 0.03 radians, a footprint of less than one kilometer, and a scan time of 4 seconds.

The POLarization and Directionality of the Earth’s Reflectances (POLDER) is a spaceborne passive radiometer that was onboard the Japan Aerospace Exploration Agency’s Advanced Earth Observing Satellite. POLDER has also been utilized in several airborne investigations to perform instrument calibration and to provide measurements of surface reflectance and solar radiation. POLDER has a ground spatial resolution of 7 km x 6 km at nadir and operates across eight discrete spectral bands (443 nm - 910 nm).