CalWater was a multi-year campaign conducted during the boreal winter over the Sierra Nevada mountain range from 2009 to 2015. NASA was a significant participant only in the 2015 deployment (CalWater 2015), providing the NASA ER-2 and various instruments. The primary goals of CalWater were to study how atmospheric rivers influence hydrometeorology and how aerosols affect clouds and precipitation processes. Measurements of aerosols, cloud properties, precipitation, and water vapor were gathered using airborne, ship-borne, and ground-based sensors. CalWater was a collaborative effort involving NOAA, the Department of Energy (DoE), the National Science Foundation (NSF), and NASA.
This campaign had multiple deployments from 2009-2015, but only the 2015 deployment is included in this inventory as NASA did not participate in earlier deployments.
The Tail Doppler Radar (TDR) is an airborne vertically scanning, pulse Dopper X-band radar operated by NOAA. It is installed on the tail of the research aircraft and is typically equipped on NOAA’s P-3 aircraft for hurricane and precipitation research missions. TDR measures radar reflectivity and Doppler wind velocities at the 9315 MHz frequency band. It has a horizontal beam width of 1.35 degrees and a range gate spacing of 150 or 300 meters.
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.
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 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 Airborne Visible/Infrared Imaging Spectrometer - Classic (AVIRIS-C) is a passive imaging spectrometer developed at the Jet Propulsion Laboratory (JPL). It collects visible and infrared images across 224 spectral channels in the 380 to 2510 nm range. It has a horizontal resolution of 20 m and a swath width of 12 km at an altitude of 20 km. It operates at a scan rate of 12 Hz. AVIRIS-C has been replaced by AVIRIS-Next Generation (AVIRIS-NG), but it still remains in use.
The High Altitude Monolithic Microwave integrated Circuit (MMIC) Sounding Radiometer (HAMSR) is an airborne microwave sounder developed by the Jet Propulsion Laboratory through the NASA Instrument Incubator Program. HAMSR measures brightness temperature, which can be used to derive three-dimensional profiles of temperature, water vapor, and cloud liquid water in the atmosphere. It operates across 25 spectral channels in three microwave bands (50-60 GHz, 118 GHz, 183 GHz) and has a sampling frequency of 5 seconds. HAMSR has a horizontal spatial resolution of 2 km at nadir and a field of view of approximately 40 km at an altitude of 20 km.
Earth Science > Atmosphere > Atmospheric Temperature
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 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.
Soil moisture probes are in situ ground-based sensors that measure soil water content. The most common type of soil moisture probes used for scientific research use dielectric permittivity techniques, such as capacitance or time-domain reflectometry sensors. These types of probes measure the charge-storage capacity of the soil to determine the soil moisture content. They typically operate at frequencies around 50 MHz and above to reduce sensitivity to salinity. Soil moisture probes provide continuous measurements and are relatively easy to deploy.
The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, allowing CCN particles to become detectable. The particles are then measured with an optical particle counter (OPC). CNC can detect particles from 0.75 to 10 μm in diameter and operates at a sampling rate of 1 Hz. It is suitable for both airborne and ground-based operations.
Rain gauges are ground-based instruments that measure liquid precipitation amounts directly over a specified period. Different rain gauges, such as tipping buckets and weighing gauges, collect and record data in various ways. Because of their small size and easy setup, rain gauges can be placed in different locations and are often used alongside other precipitation instruments like disdrometers to gather more details, such as precipitation rate and size distribution.
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.
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 Aethalometer is an in situ aerosol measuring device made by Magee Scientific. It can be used on both airborne and ground-based platforms. It collects aerosols through a filter tape and gauges the attenuation of transmitted light to assess black carbon particle levels. The Aethalometer works across seven optical wavelengths (370, 470, 520, 590, 660, 880, and 950 nm) and delivers data at a rate of 1 Hz. It has a measurement range of 0-500 μg per cubic meter and a resolution of 0.1 μg per cubic meter.
The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, allowing CCN particles to become detectable. The particles are then measured with an optical particle counter (OPC). CNC can detect particles from 0.75 to 10 μm in diameter and operates at a sampling rate of 1 Hz. It is suitable for both airborne and ground-based operations.
The NOAA Wide Swath Radar Altimeter (WSRA) is an airborne radar system developed by ProSensing. It measures radar backscatter to determine significant wave height, ocean wave spectra, wave topography, and rainfall rate. WSRA is typically flown on NOAA P-3D aircraft for hurricane missions. It operates at 16 GHz and has a sampling rate of 10 Hz. WSRA has a spatial resolution of 5.5-8 km in the along-track direction and 2 km in the across-track direction. It has a total swath width of 3 km.
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
W-band radars are highly sensitive radars used for atmospheric research. They operate around the 94-95 GHz frequency band, allowing for the detection of small water droplets. W-band radars are used for cloud and precipitation studies since they can provide more detailed observations than typical weather radars. They can be deployed on research vessels, aircraft, and mobile ground-based platforms.
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 Stepped Frequency Microwave Radiometer (SFMR) is a passive airborne C-band radiometer developed by ProSensing Inc. It measures brightness temperature across six frequency bands from 4.6 to 7.2 GHz. These measurements can be used to estimate rain rates and surface winds. SFMR is primarily employed for research missions involving hurricanes and tropical storms, notably by NOAA’s Hurricane Research Division (HRD). It has a spatial resolution of approximately 1.5 km and a temporal resolution of roughly 4 seconds.
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
The Tail Doppler Radar (TDR) is an airborne vertically scanning, pulse Dopper X-band radar operated by NOAA. It is installed on the tail of the research aircraft and is typically equipped on NOAA’s P-3 aircraft for hurricane and precipitation research missions. TDR measures radar reflectivity and Doppler wind velocities at the 9315 MHz frequency band. It has a horizontal beam width of 1.35 degrees and a range gate spacing of 150 or 300 meters.
The Airborne eXpendable BathyThermograph (AXBT) is an in situ sensor that measures ocean temperature and conductivity. It is deployed from an aircraft using a small parachute and floats to the ocean surface after impact. The floating portion of the instrument then releases a probe into the ocean that collects profile measurements to a depth of about 1000 meters. AXBT has a vertical descent of about 1.5 meters per second.
Sunphotometers are passive optical sensors that measure the amount of sunlight. They are pointed directly at the sun to measure direct sunlight and not sunlight scatter from aerosols. These measurements can be used to determine the aerosol optical depth by following Beer’s Law. Sunphotometers have been deployed on aircraft, research vessels, and field sites for aerosol research and monitoring.
A pyranometer is a ground-based or airborne radiation sensor that measures solar irradiance across a hemispherical field of view. It detects the amount of solar energy reaching the surface, capturing both direct and diffuse sunlight. Pyranometers operate within a spectral range of 280-3000 nm. They are most commonly used for solar monitoring, climate research, weather forecasting, agriculture, and energy management.
Earth Science > Atmosphere > Atmospheric Radiation > Solar Irradiance
Earth Science > Atmosphere > Atmospheric Radiation > Solar Radiation
Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentrations. CPCs determine aerosol levels by condensing fluid onto particles, causing them to grow to sizes detectable by optical scattering. Typically, CPCs can detect particles ranging from 7 nm to 3 μm, measure concentrations up to 100,000 particles per cubic centimeter, and provide readings every second. CPCs are manufactured by TSI Incorporated and can be used on airborne, shipborne, and ground-based platforms.
The Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It applies Beer's Law to measure the change in light transmission of aerosol particles. These measurements help determine aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a 1-second time resolution. It is usually deployed on aircraft, but it can also be used on ships and vehicles.
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.
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 Ka-band ARM Zenith Radar (KAZR) is a ground-based Doppler radar operated by the Department of Energy (DoE) Atmospheric Radiation Measurement (ARM) User Facility. It is a 35 GHz, zenith-pointing radar that provides vertical profiles of clouds by measuring radar reflectivity, Doppler velocity, and spectrum width. KAZR has a beamwidth of 0.3 degrees, a maximum range of 15 kilometers, and a spatial resolution of 30 meters. KAZR is available at several DoE ARM sites and can be deployed for mobile observations.
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 determine the column amounts of water vapor and liquid water in the atmosphere. MWR has a field of view (FOV) ranging from about 5.9 to 4.5 degrees depending on the channel and typically has a time resolution of 20 seconds for sky-view observations.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
Earth Science > Atmosphere > Atmospheric Water Vapor
W-band radars are highly sensitive radars used for atmospheric research. They operate around the 94-95 GHz frequency band, allowing for the detection of small water droplets. W-band radars are used for cloud and precipitation studies since they can provide more detailed observations than typical weather radars. They can be deployed on research vessels, aircraft, and mobile ground-based platforms.
The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, allowing CCN particles to become detectable. The particles are then measured with an optical particle counter (OPC). CNC can detect particles from 0.75 to 10 μm in diameter and operates at a sampling rate of 1 Hz. It is suitable for both airborne and ground-based operations.
The Total Sky Imager (TSI) is a ground-based, optical instrument developed by Yankee Environmental Systems (YES), Inc. TSI provides full-color, hemispheric images of the sky during the day using a charge-coupled device (CCD) imager. It also measures fractional sky cover and sun obscuration caused by clouds. TSI can be mounted on mobile platforms such as trailers and research vehicles, enabling it to collect cloud cover data in different locations during field studies.
The Micropulse Lidar (MPL) is a ground-based lidar system used for cloud detection. It measures lidar backscatter at 532 nm to retrieve cloud properties such as cloud top and base height. It can also be used for the detection of aerosols. MPL has a vertical resolution of 15 m and a maximum range of 18 km. MPL can operate autonomously and typically provides 10-second averaged data.
Earth Science > Spectral/engineering > Lidar > Lidar Depolarization Ratio
The High Spectral Resolution Lidar (HSRL) is an airborne lidar system developed at NASA Langley Research Center (LaRC). It uses the HSRL technique at 532 nm and the standard backscatter technique at 1064 nm to provide profile measurements of aerosol backscatter, extinction, and depolarization. The profiles of aerosol backscatter and depolarization typically have a vertical resolution of 30 m and a horizontal resolution of about 1 km. For the extinction profiles, the vertical resolution is 300 m with a horizontal resolution of approximately 6 km. HSRL is usually flown during investigations to validate observations from the CALIPSO spaceborne lidar.
Earth Science > Spectral/engineering > Lidar > Lidar Depolarization Ratio
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 with a size resolution of 0.013 mm at 0.2 mm. The TDMA is often combined with an Aerodynamic Particle Sizer (APS) to enable measurements of particles in the submicron range. A typical measurement sequence of TDMA takes approximately 45 minutes to complete.
Nephelometers are in situ optical sensors that can be airborne or ground-based. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate at three wavelengths: 450 nm, 550 nm, and 700 nm, with a typical time resolution of 1 Hz.
Ceilometers are ground-based remote sensing sensors that measure cloud ceilings and vertical visibility. They utilize a laser or another light source to detect backscatter from clouds, precipitation, and aerosols. Ceilometers provide detailed and precise measurements under all weather conditions and are cost-effective to operate. They are commonly used in boundary layer and cloud research.
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.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
Rosemount Pressure Probes are in situ airborne pressure sensors manufactured by Rosemount, Inc. They provide high-precision atmospheric pressure measurements and are typically used to gather flight-level meteorological observations. Rosemount Pressure Probes consist of various pressure transducers, gauges, and multivariable and coplanar transmitters.
Rosemount Temperature Probes are in situ airborne temperature sensors manufactured by Rosemount, Inc. They provide atmospheric temperature measurements and are typically used to collect flight-level meteorological observations. Rosemount Temperature Probes consist of temperature transmitters, thermocouple sensors, resistance temperature detectors, and other temperature sensors.
Earth Science > Atmosphere > Atmospheric Temperature > Upper Air Temperature
Earth Science > Atmosphere > Atmospheric Temperature
The Aircraft-Integrated Meteorological Measurement System (AIMMS) is an in situ airborne sensor developed by Aventech Research, Inc. It measures the aircraft's position, altitude, temperature, relative humidity, static pressure, and three-dimensional wind vector. The system includes an Inertial Measurement Unit (IMU), Global Positioning System (GPS), Air Data Probe (ADP), and a central processing module (CPM) for processing the GPS data. AIMMS provides data at a rate of up to 20 Hz and can operate in temperatures ranging from -20 to 50 degrees Celsius.
Earth Science > Atmosphere > Atmospheric Temperature > Upper Air Temperature
Earth Science > Atmosphere > Atmospheric Temperature
Video cameras capture video recordings of various phenomena for research purposes. They are used on aircraft to provide continuous views of weather and terrain below the flight path. Video cameras are also employed to verify the aircraft's flight track. Additionally, they are deployed at field sites to monitor changes in vegetation, land cover, clouds, air quality, glaciers, and other Earth science phenomena.
The Cloud Droplet Probe (CDP) is an in situ cloud probe manufactured by Droplet Measurement Technologies. It measures the particle size distribution and concentration for cloud particles in the 2-50 μm size range. CDP detects pulses of light scattered from a laser (658 nm) to count and size individual cloud droplets. CDP has a typical measurement rate of 1 Hz and can detect concentrations of up to 2000 particles per cubic centimeter.
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.
Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentrations. CPCs determine aerosol levels by condensing fluid onto particles, causing them to grow to sizes detectable by optical scattering. Typically, CPCs can detect particles ranging from 7 nm to 3 μm, measure concentrations up to 100,000 particles per cubic centimeter, and provide readings every second. CPCs are manufactured by TSI Incorporated and can be used on airborne, shipborne, and ground-based platforms.
The Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It applies Beer's Law to measure the change in light transmission of aerosol particles. These measurements help determine aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a 1-second time resolution. It is usually deployed on aircraft, but it can also be used on ships and vehicles.
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 Optical Particle Counter (OPC) is an optical device used to measure aerosol particle size and concentration. It determines particle size and concentration by detecting the intensity of scattered light. Most OPCs operate within the visible to near-infrared wavelengths (500-1100 nm) and have a time resolution of 1 second. They are typically used to measure particles larger than 0.5 μm in diameter. OPCs can be used for both airborne and ground-based applications.
The Passive-Cavity Aerosol Spectrometer Probe (PCASP) is an in situ airborne optical spectrometer manufactured by Droplet Measurement Technologies. It detects light scattered by particles to determine aerosol size distribution and concentration within the 0.1 to 3.0 μm range. PCASP operates at a wavelength of 632 nm and typically samples at 10 Hz.
The Particule Volume Matter (PVM-100A) is an in situ airborne cloud probe manufactured by Gerber Scientific. It measures liquid water content and the effective radius of cloud droplets by measuring the scattering intensity proportional to the droplets' density and particle surface area density. PVM-100A operates at 780 nm and has a measurement rate of up to 5000 Hz. It can measure droplets in the size range of 3-50 μm diameter. The ground-based model of this instrument is PVM-100.
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 a single instrument. CAPS measures the size distribution of aerosol, cloud, and liquid droplets for particles between 50-1600 μm in size, with a time resolution of 1 Hz. It can also capture images of cloud particles and provide measurements of temperature, pressure, and LWC.
A Tunable Diode Laser Absorption Spectrometer (TDLAS) is an in situ optical spectrometer used either on aircraft or on the ground. TDLAS detects the wavelength-dependent absorption of light to measure the concentrations of various trace gases. It can also identify the gas species' temperature, pressure, velocity, and mass flux when applicable. TDLAS typically has a time resolution of 1 second.
The Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) is an in situ spectrometer developed by Droplet Measurement Technologies. It can be used on both airborne and ground-based platforms to measure aerosol size distribution and concentration. UHSAS determines particle size by detecting the peak light signals from aerosol particles illuminated by a 1054 nm laser. It can sample particles in the 60–1000 nm size range and operates at a sampling frequency of 10 Hz.
The Single Particle Soot Photometer (SP2) is an in situ laser-induced photometer developed by Droplet Measurement Technologies. SP2 measures the black carbon (BC) mass in individual aerosol particles, along with their optical and physical properties that contain BC. The device detects aerosol particles with diameters of 200-400 nm and can analyze up to 25,000 particles per second. It operates at a sampling rate of 1 Hz and uses a wavelength of 1.06 μm. It can be used on airborne or ground-based platforms and paired with a Humidified-Dual SP2 (HD-SP2).
The SEA Model WCM-2000 Multi Element Water Content System (WCM-2000) is an in situ airborne sensor manufactured by Science Engineering Associates (SEA), Inc. It directly measures liquid water content (LWC) and total water content (TWC) within clouds. It can also be used to derive ice water content (IWC). WCM-2000 measures LWC and TWC in the range of 0 to 10 grams per cubic meter. It has a typical data rate of 1 Hz.
The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, allowing CCN particles to become detectable. The particles are then measured with an optical particle counter (OPC). CNC can detect particles from 0.75 to 10 μm in diameter and operates at a sampling rate of 1 Hz. It is suitable for both airborne and ground-based operations.
The Cloud Imaging Probe (CIP) is an in situ airborne optical array probe manufactured by Droplet Measurement Technologies. It captures cloud particle images by recording shadows as particles pass through a laser. Additionally, it provides data on particle size distribution and cloud liquid water content. CIP typically has a resolution of 25 μm and can measure particles ranging from 12.5 μm to 1.55 mm.
The Cloud Spectrometer and Impactor (CSI) is an in situ airborne probe that measures total condensed water (TCW) content in clouds. It combines a counterflow virtual impactor (CVI) with a lightweight cloud droplet probe. It can measure cloud particles ranging from 2 to 50 μm in size and has a typical sampling frequency of 1 second.
The Fast Cloud Droplet Probe (FCDP) is an in situ airborne cloud probe manufactured by SPEC Inc. The FCDP measures the concentration and size of cloud droplets by detecting light scattered by particles. It detects particles with diameters ranging from 1.5 to 50 microns and typically records measurements at 1 Hz.
Nephelometers are in situ optical sensors that can be airborne or ground-based. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate at three wavelengths: 450 nm, 550 nm, and 700 nm, with a typical time resolution of 1 Hz.
The Cloud and Aerosol Spectrometer (CAS) is an in situ airborne spectrometer manufactured by Droplet Measurement Technologies. It measures light scattering at 658 nm to determine aerosol and cloud particle size distributions from 0.51 to 50 μm. It also provides measurements of the refractive index and particle shape. CAS has a typical time resolution of 1 Hz and can measure concentrations greater than 1,000 particles per cubic meter.
Thermo Scientific Gas Analyzers are in situ gas analyzers manufactured by ThermoFisher Scientific. They provide precise measurements of various trace gases such as ozone, carbon dioxide, carbon monoxide, and sulfur dioxide. Thermo Scientific Gas Analyzers can be deployed on aircraft, research vessels, and ground-based platforms.
The 2D-Stereo Particle Probe (2D-S) is an in situ airborne optical imaging device developed by SPEC Inc. It uses two diode laser beams to create stereo images of cloud particles via linear array shadowing. These images allow for the determination of cloud particle size distribution, particle number concentration, and ice or liquid water content. 2D-S has a resolution of 10 µm and can measure hydrometeors ranging from 25 to 1280 µm.
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.
