The Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) was a NASA-led, multi-year campaign that studied marine boundary layer cloud systems and aerosols. ACTIVATE consisted of six deployments from 2020 to 2022 over the Western North Atlantic Ocean. NASA's B-200 and Falcon aircraft were equipped with remote and in situ sensors to collect measurements of marine cloud and aerosol properties within the boundary layer. ACTIVATE was part of the Earth Venture Suborbital-3 (EVS-3) program.
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.
Earth Science > Atmosphere > Atmospheric Temperature
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 Second Generation High Spectral Resolution Lidar (HSRL-2) is an airborne lidar developed by the NASA Langley Research Center. HSRL-2 measures aerosol backscatter at the 355, 532, and 1064 nm wavelengths and aerosol extinction at the 355 and 532 nm wavelengths. It has a horizontal resolution of 1-2 km and a vertical resolution of 15 m, and it takes measurements roughly every 0.5 seconds. It replaced the High Spectral Resolution Lidar (HSRL).
Earth Science > Atmosphere > Atmospheric Temperature
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 Continuous O3 Monitor uses ultraviolet beams to monitor the ozone in the air that is pulled into the instrument. The Continuous O3 Monitor has a high temporal resolution, and can take highly accurate measurements. The Continuous O3 Monitor is mounted to an aircraft. The instrument is manufactured by 2B Technologies.
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.
The Particle Into Liquid Sampler (PILS) is an in situ aerosol sampler manufactured by Brechtel Manufacturing Inc. PILS can be utilized by both ground-based and airborne platforms to collect continuous measurements of ambient aerosol bulk composition. The particles sampled by PILS are mixed with saturated water vapor to produce droplets that are analyzed by either an ion chromatograph (IC) or a total organic carbon detector (TOC). PILS can measure aerosol particles with a size range of 70 nm to 2.5 μm and has a time resolution of 3 min for airborne measurements and 15 min for ground-based.
Earth Science > Atmosphere > Aerosols > Chemical Composition
The Laser Aerosol Spectrometer (LAS) is an in situ airborne spectrometer manufactured by TSI, Inc. LAS provides measurements of particle size based on the light scattering of the sampled particles. It operates at 633 nm wavelength and has a particle size range of 0.09 to 7.5 μm. LAS can provide complete particle size distributions at a rate of 10 Hz. LAS is typically used as part of aerosol instrument suites such as NASA’s Langley Aerosol Research Group Experiment (LARGE) and NOAA’s Aerosol Microphysical Properties (AMP).
The Scanning Mobility Particle Sizer (SMPS) is an in situ airborne or ground-based aerosol sensor manufactured by TSI Incorporated. SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles to determine the size distribution. It also measures the number of aerosol particles by using a condensation particle counter (CNC). It can detect particles within the size range of 10-1000 nm and can provide measurements typically around 10 seconds per scan.
Earth Science > Atmosphere > Aerosols
Earth Science > Atmosphere > Aerosols > Chemical Composition
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.
Earth Science > Atmosphere > Aerosols > Chemical Composition
The Picarro gas concentration analyzer is an in situ airborne or ground-based sensor manufactured by Picarro, Inc. It uses Wavelength-Scanned-Cavity Ring Spectroscopy (WS-CRDS) to measure trace gases such as carbon dioxide, carbon monoxide, methane, and water vapor. For carbon dioxide measurements, the laser within Picarro operates at 1603 nm wavelength and 1651 nm wavelength for methane and water vapor measurements. Picarro has a typical sampling time of 2.5 seconds. Depending on the model, Picarro can also provide measurements of carbon isotopes for gas concentrations.
The Condensation Nuclei Counter (CNC) is optical method for
counting atmospheric aerosol particles.
Earth Science > >
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.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity > Relative Humidity
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
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 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.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Dew Point Temperature
The Cloud Imaging Probe (CIP) is an in situ airborne optical array probe manufactured by Droplet Measurement Technologies. CIP records cloud particle images by capturing the shadow of the particles as they pass through the laser. It also provides information on the particle size distribution and cloud liquid water content. CIP has a typical resolution of 25 μm and can measure particles in the size range of 12.5 μm - 1.55 mm.
The Fast Cloud Droplet Probe (FCDP) is an in-situ airborne cloud probe manufactured by SPEC Inc. FCDP measures the concentration and size of cloud droplets by detecting the amount of light scattered by the particles. It measures particles within the diameter size range of 1.5-50 microns and has a typical measurement frequency of 1 Hz.
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 Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It uses Beer's Law to measure the change in light transmission of aerosol particles. These measurements can be used to derive aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a temporal resolution of 1 second. It is typically deployed on aircraft, but it can be deployed on other platforms such as ships and vehicles.
Nephelometers are in situ airborne or ground-based optical sensors. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate across three wavelengths: 450 nm, 550 nm, and 700 nm, and have a typical time resolution of 1 Hz.
