Tropical Composition, Cloud and Climate Coupling

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 Cryogenic Frost Point Hygrometer (CFH) is a balloon-borne hygrometer developed by the University of Colorado. CFH uses the chilled-mirror principle to measure water vapor from the Earth's surface to the mid-stratosphere. It is more sensitive to water vapor compared to standard radiosondes, allowing it to measure dew point temperatures with an accuracy of 0.2 K. CFH collects measurements about every 2 seconds during the balloon’s flight and has a vertical resolution of about 50m in the troposphere to 100m in the stratosphere.

This data will be added in future versions.

This data will be added in future versions.

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 MODIS/ASTER Airborne Simulator (MASTER) is an airborne scanning spectrometer developed at NASA Ames Research Center (ARC) with Jet Propulsion Laboratory (JPL) to support validation of MODIS and ASTER retrieval algorithms. MASTER is maintained and operated by the Airborne Sensor Facility (ASF) at ARC. It provides visible-shortwave infrared and thermal infrared imagery and operates across 50 spectral channels in the 0.4-13 μm wavelength range. MASTER has a pixel spatial resolution of 5 to 50 meters and has a swath width of 1.87 to 37.25 km depending on the flight altitude. It has a typical scan rate of 6.25 Hz.

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 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 the emitted thermal radiation between 3.3 and 18 microns at high spectral resolution. These measurements can be used to derive atmospheric profiles of temperature and water vapor in 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 has a sampling frequency of 0.5 s and an absolute radiance accuracy of 0.2 K.

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 Advanced Microwave Precipitation Radiometer (AMPR) is an airborne passive microwave radiometer. AMPR provides calibrated brightness temperature, which can be used to derive cloud and precipitation properties. It operates across four microwave channels: 10.7, 19.35, 37.1, and 85.5 GHz. These frequencies are sensitive to precipitation, thus making AMPR well-suited for rain event studies.

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.

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 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 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.

This data will be added in future versions.

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.

This data will be added in future versions

a miniature, lightweight, low-power cloud particle spectrometer that measures droplets in the range of 2-50 µm in concentrations as high as 2000 particles/cm3

The Cloud Spectrometer and Impactor (CSI) combines the counterflow virtual impactor with a new lightweight cloud droplet probe to allow for detailed studies of total condensed water (TCW), liquid and ice, in clouds. The CSI can measure TCW from ~ 1 mg/m3 to several g/m3 depending on the configuration; in addition particle sizes from 2 to 50 μm are resolved with the droplet probe. The instrumentation can be mounted externally on most aircraft.

This data will be added in future versions

The GC-MS instrument is a combination of two instruments: a gas chromatograph and a mass spectrometer. It is used on airborne platforms to study atmospheric chemistry, specifically non-methane halocarbons and volatile organic compounds.

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 Single Particle Soot Photometer (SP2) is a laser-induced photometer manufactured by Droplet Measurement Technologies. SP2 provides measurements of the black carbon (BC) mass content of individual aerosol particles as well as the optical and physical properties of the particles containing BC. SP2 can be utilized on airborne or ground-based platforms and can be deployed with a paired Humidified-Dual SP2 (HD-SP2). It can detect aerosol particles with a diameter size of 200-400 nm and can measure 25,000 particles/second.

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.

This data will be added in future versions

The Whole Air Sampler (WAS) is an airborne in-situ instrument that collects samples of air for analysis of trace gases, such as nonmethane hydrocarbons (NMHCs), Halocarbons, Alkyl Nitrates, and various sulfur compounds that are present in the troposphere. Air samples collected via the WAS then undergo gas chromatography and mass spectrometry to determine which gasses are present in the sample. The WAS collects samples every minute, which enables scientists to get a clear picture of the chemical composition of the environment as research aircraft pass through.

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 PAN and Trace Hydrohalocarbon ExpeRiment (PANTHER) is an in situ airborne analyzer. It uses electron capture detection and gas chromatography techniques to measure various trace gases such as methane, peroxyacyl nitrate (PAN), and carbon monoxide. PANTHER has a sampling frequency of 60 to 120 seconds and has an accuracy of around 2% for most species except for PAN (10%). The development of PANTHER was funded through NASA’s Instrument Incubator Program and NOAA’s Climate and Global Change Program.

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 Airborne Compact Atmospheric Mapper (ACAM) is a remote-sensing airborne spectrometer designed at NASA's Goddard Space Flight Center (GSFC). It utilizes two thermally stabilized spectrometers to collect measurements of nitrogen dioxide, sulfur dioxide, ozone, formaldehyde, and aerosols in the ultraviolet, visible, and near-infrared spectral range (310-900 nm). ACAM typically operates at a spatial resolution of 30 m and a temporal resolution of 10 Hz. Measurements from ACAM can be used for calibration and validation of observations from the Aura satellite.

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 Charged-couple device (CCD) Actinic Flux Spectroradiometer (CAFS) is an in situ airborne spectroradiometer developed by the Atmospheric Radiation Investigations and Measurements (ARIM) laboratory at NCAR. CAFS measures spectrally resolved ultraviolet and visible actinic flux between 280-650 nm. These measurements can be used to derive the photolysis frequencies for several chemical compounds such as ozone, nitrogen dioxide, formaldehyde, and nitrate. CAFS has a temporal resolution of 1 Hz and a wavelength resolution of about 1.8 nm at 297 nm.

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 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.

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.

The NOAA Frost Point Hygrometer (FPH) is a balloon-borne sensor that collects profile measurements of atmospheric water vapor. It uses the chilled-mirror principle to measure the frost or dew point temperature up to 28 km in the atmosphere. FPH takes measurements at a vertical resolution of 5-10 m and a temporal resolution of 1-2 seconds.

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 2D-Stereo Particle Probe (2D-S) is an in situ airborne optical imaging probe developed by SPEC Inc. The 2D-S uses two diode laser beams to produce stereo cloud particle images through linear array shadowing. Through the imagery, cloud particle size distribution, particle number concentration, and ice/liquid water content can be determined. It has a resolution of 10 µm and can measure hydrometeors in the 25-1280 µm range.

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 Measurements of Atmospheric Carbon Dioxide Over Northwestern North America (MACDON-NA) is an in situ airborne gas analyzer. It is a modified LI-COR model 6252 infrared gas analyzer instrument that measures atmospheric carbon dioxide (CO2). The CO2 measurement is based on the difference in the absorption of infrared radiation passing through two gas sampling cells. MACDON-NA operates at the 4.26 μm wavelength and a constant pressure of 250 torr. It has a typical time response of 0.1 seconds.

This data will be added in future versions

This data will be added in future versions

The Thermal-Dissociation Laser Induced Fluorescence (TD-LIF) is an in situ airborne sensor developed at UC Berkeley. It uses a combination of the TD and LIF techniques to measure nitrogen dioxide (NO2), peroxynitrates, nitric acid (HNO3), and other stable organic nitrates in the atmosphere. TD-LIF operates at the 585 nm wavelength and has a typical measurement frequency of 1 Hz.

The Precipitation and Imaging Probe (PIP) measures the concentration and records images of cloud particles from approximately 500-30000 microns in diameter with a resolution of 100 microns per pixel.

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 Soluble Acidic Gases and Aerosols (SAGA) is an in situ airborne sampler owned and operated by the University of New Hampshire. It uses a mist chamber and ion chromatography to collect and analyze select aerosol species. It can provide samples of nitric acid, chloride, sulfates, nitrates, chloride, sodium, potassium, ammonium, and calcium. SAGA has a typical sampling frequency of 5 to 15 minutes and has a detection limit of 1 to 25 pptv depending on the sampled species.

The Differential Absorption Carbon monOxide Measurements (DACOM) is an airborne in situ spectrometer system. It uses the differential absorption technique and an infrared tunable diode laser (TDL) to collect measurements of nitrous oxide (N2O), carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) in the atmosphere. DACOM operates across the 4.7, 4.5, and 3.3 μm wavelengths to access the absorption lines for CO, N2O, and CH4. It has a measurement frequency of 5 Hz and a precision of about 1 ppbv.

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.

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 CalTech Chemical Ionization Mass Spectrometer (CIT-CIMS) is an in situ airborne single mass spectrometer. CIT-CIMS utilizes CF3O-ion chemistry and compact time-of-flight and triple quadrupole spectrometers to measure specific atmospheric trace gases such as nitric acid, hydrogen peroxide, and sulfur dioxide. It was designed with rapid scan capabilities, allowing it to operate at a high temporal resolution (10 Hz) and detect a wide mass range. CIT-CIMS is typically used for airborne observations, but it can be used for ground-based observations as well.

The Differential Absorption Lidar (DIAL) is an airborne lidar system designed at NASA’s Langley Research Center (LaRC). It uses four lasers to detect lidar backscatter to provide profile measurements of ozone and aerosols in the atmosphere. DIAL operates in the ultraviolet (289-300 nm) for ozone measurements and operates in the visible (572-600 nm) and infrared (1064 nm) for aerosols. It has a horizontal spatial resolution of approximately 15 km and has a measurement accuracy of 5 ppbv.

The Whole Air Sampler (WAS) is an airborne in-situ instrument that collects samples of air for analysis of trace gases, such as nonmethane hydrocarbons (NMHCs), Halocarbons, Alkyl Nitrates, and various sulfur compounds that are present in the troposphere. Air samples collected via the WAS then undergo gas chromatography and mass spectrometry to determine which gasses are present in the sample. The WAS collects samples every minute, which enables scientists to get a clear picture of the chemical composition of the environment as research aircraft pass through.

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 Charged-couple device (CCD) Actinic Flux Spectroradiometer (CAFS) is an in situ airborne spectroradiometer developed by the Atmospheric Radiation Investigations and Measurements (ARIM) laboratory at NCAR. CAFS measures spectrally resolved ultraviolet and visible actinic flux between 280-650 nm. These measurements can be used to derive the photolysis frequencies for several chemical compounds such as ozone, nitrogen dioxide, formaldehyde, and nitrate. CAFS has a temporal resolution of 1 Hz and a wavelength resolution of about 1.8 nm at 297 nm.

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 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 measure water vapor in the atmosphere. DLH operates in the near-infrared region at around 1.4 μm and has a measurement frequency of 100 Hz. It can provide accurate measurements of water vapor even while flying through clouds.

The Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties such as size distribution, number concentration, and scattering and absorption coefficient. LARGE consists of multiple instruments including the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Particle-Into-Liquid Sampler (PILS), Particle Soot Absorption Photometer (PSAP), Cloud and Aerosol Spectrometer (CAS), Cloud Imaging Probe (CIP), and additional cloud and aerosol sensors. The LARGE instruments operate across the 450-700 nm wavelength range, can detect particles in the size range between 0.003-20μm, and have a measurement frequency of 1 Hz. It is typically used for airborne measurements, but it also can be deployed on ground-based platforms such as vehicles.

The Airborne Second Generation Precipitation Radar (APR-2) is a cross-track scanning, dual-frequency airborne precipitation radar. It measures radar backscatter from rainfall to provide measurements of reflectivity, Doppler velocity, and linear depolarization ratio (LDR). APR-2 operates at 13.4 GHz and 35.6 GHz and has a pulse repetition frequency (PRF) of 5000 Hz. At a flight altitude of 11,000 feet, it has a horizontal resolution of 730 m at 13.4 GHz and 920 m at 35.6 GHz. APR-2 has a vertical resolution of 60 m and a ground swath width of 10 km.

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 Lidar Atmospheric Sensing Experiment (LASE) is an airborne lidar system developed at NASA 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 200m and a vertical resolution of 30m. It has a horizontal resolution of 5 km and a vertical resolution of 0.2 km for water vapor measurements.

The 2D-Stereo Particle Probe (2D-S) is an in situ airborne optical imaging probe developed by SPEC Inc. The 2D-S uses two diode laser beams to produce stereo cloud particle images through linear array shadowing. Through the imagery, cloud particle size distribution, particle number concentration, and ice/liquid water content can be determined. It has a resolution of 10 µm and can measure hydrometeors in the 25-1280 µm range.

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.