Axial Cyclone Cloud-water Collector

The AC3 was designed at NASA Langley inspired by a previous Straub and Collett (2004) version. The probe samples in-situ cloud water by separating droplets from the main airflow.  This is accomplished by imparting swirl on an axial flow following an in-line stator, and collecting droplets that have impacted on the probes outer walls. Cloud-water is then transferred into the aircraft cabin using teflon tubing and manually collected into vials. Cloud-water can then be analyzed by a number of laboratory analytical techniques including ion-chromatography, pH electrodes, or total organic content. The probe utilizes a shutter to inhibit sample contamination by aerosols.    

Instrument Type: 
Aircraft: 
C-130 - WFF, P-3 Orion - WFF, HU-25 Falcon - LaRC
Point(s) of Contact: 

Langley Cloud Probes

The LARGE group operates a suite of probes to measure in-situ cloud microphysical properties. Probes are typically mounted at an under-wing or wing-tip position in unperturbed air. The package of probes can be tailored to specific science objectives or mounting-point availability considerations. The following probes are available:

CAPS (Cloud, Aerosol, Precipitation Spectrometer), Droplet Measurement Technologies.  The CAPS contains individual sensors.  The CAS (Cloud Aerosol Spectrometer) measures size distributions of clouds and aerosols between 0.5-50µm diameter using forward-scattered light intensity from a 658nm laser. Response is calibrated with glass beads. The CIP (Cloud Imaging Spectrometer) measures size distributions of droplet and precipitation particles between 15-150µm diameter recording shadows on an optical array. The CIP is calibrated using a spinning disk. A hotwire is also used to measure total liquid-water-content. Each probe utilizes a local measurment of airspeed, temperature, and static pressure for quantification and has de-icing capability.
CDP (Cloud Droplet Probe), Droplet Measurement Technologies. The CDP measures droplet and aerosol size distributions between 2-50µm diameter using forward-scattering from a 658nm laser.  The probe is calibrated with glass beads and has de-icing capability.
WCM-2000 (Science Engineering Associates).  Measures Liquid Water Content (LWC) using two independent hotwire elements, Total Water Content (TWC) using a scoop sensor, and an element oriented parallel with the airstream as a control to establish the background response at that specific airspeed, temperature, and pressure.  Ice Water Content (IWC) is calculated as the difference between TWC and LWC. Each element operates by maintaining a constant temperature, and the current necessary to maintain that temperature is related directly with water content.  
 

Instrument Type: 
Aircraft: 
DC-8 - AFRC, P-3 Orion - WFF, C-130 - WFF, HU-25 Falcon - LaRC
Point(s) of Contact: 

Langley Aerosol Mass Spectrometer

Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (AMS) operated by the Langley Aerosol Research Group Experiment (LARGE).  Provides fast-response non-refractory submicron aerosol mass concentrations (e.g., organics, sulfate, nitrate, ammonium, and chloride) and tracer m/z fragments (e.g., m/z44, m/z55, etc.).   

Instrument Type: 
Aircraft: 
DC-8 - AFRC, P-3 Orion - WFF, HU-25 Falcon - LaRC, C-130 - WFF
Point(s) of Contact: 

HU25 ACTIVATE Upper Probes

Aerosol Cloud Meteorology Interactions Over the Western Atlantic Experiment (ACTIVATE)

NASA’s Aerosol Cloud me

Probing the Hazy Mysteries of Marine Clouds

A new NASA airborne science mission will take researchers on coordinated flights above, through and below the clouds over the western North Atlantic Ocean.

NASA Embarks on Five U.S. Expeditions Targeting Air, Land and Sea

NASA is sending five airborne campaigns across the United States in 2020 to investigate fundamental processes that ultimately impact human lives and the environment, from snowstorms along the East Coast to ocean eddies off the coast of San Francisco.

Langley Aerosol Research Group Experiment

Langley Aerosol Research Group Experiment (LARGE).  The "classic" suite of instrumenation measures in-situ aerosol micrphysical and optical properties. The package can be tailored for specific science objectives and to operate on a variety of aircraft. Depending on the aircraft, measurments are made from either a shrouded single-diffuser "Clarke" inlet, from a BMI (Brechtel Manufacturing Inc.) isokinetic inlet, or from a HIML inlet. Primary measurements include:

1.) total and non-volatile particle concentrations (3nm and 10nm nominal size cuts),
2.) dry size distributions from 3nm to 5µm diameter using a combination of mobilty-optical-aerodynamic sizing techniques,
3.) dry and humidified scattering coefficients (at 450, 550, and 700nm wavelength), and
4.) dry absorption coefficients (470, 532, and 670nm wavelength). 

LARGE derived products include particle size statistics (integrated number, surface area, and volume concentrations for ultrafine, accumulation, and coarse modes), dry and ambient aerosol extinction coefficients, single scattering albedo, angstrom exponent coefficients, and scattering hygroscopicity parameter f(RH).

Aircraft: 
DC-8 - AFRC, C-130 - WFF, P-3 Orion - WFF, HU-25 Falcon - LaRC, King Air B-200 - LaRC
Point(s) of Contact: 

Diode Laser Hygrometer

The DLH has been successfully flown during many previous field campaigns on several aircraft, most recently ACTIVATE (Falcon); FIREX-AQ, ATom, KORUS-AQ, and SEAC4RS (DC-8); POSIDON (WB-57); CARAFE (Sherpa); CAMP2Ex and DISCOVER-AQ (P-3); and ATTREX (Global Hawk). This sensor measures water vapor (H2O(v)) via absorption by one of three strong, isolated spectral lines near 1.4 μm and is comprised of a compact laser transceiver and a sheet of high grade retroflecting road sign material to form the optical path. Optical sampling geometry is aircraft-dependent, as each DLH instrument is custom-built to conform to aircraft geometric constraints. Using differential absorption detection techniques, H2O(v) is sensed along the external path negating any potential wall or inlet effects inherent in extractive sampling techniques. A laser power normalization scheme enables the sensor to accurately measure water vapor even when flying through clouds. An algorithm calculates H2O(v) concentration based on the differential absorption signal magnitude, ambient pressure, and temperature, and spectroscopic parameters found in the literature and/or measured in the laboratory. Preliminary water vapor mixing ratio and derived relative humidities are provided in real-time to investigators.

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Measurements: 
Aircraft: 
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