NASA - National Aeronautics and Space Administration

The Purdue PALMS-NG instrument measures single-particle aerosol composition using UV laser ablation to generate ions that are analyzed with a time-of-flight mass spectrometer.  The PALMS size range is approximately 150 to >3000 nm and encompasses most of the accumulation and coarse mode aerosol volume. Individual aerosol particles are classified into compositional classes.  The size-dependent composition data is combined with aerosol counting instruments from Aerosol Microphysical Properties (AMP), the Langley Aerosol Research Group Experiment (LARGE), and other groups to generate quantitative, composition-resolved aerosol concentrations.  Background tropospheric concentrations of climate-relevant aerosol including mineral dust, sea salt, and biomass burning particles are the primary foci for the ATom campaigns.  PALMS also provides a variety of compositional tracers to identify aerosol sources, probe mixing state, track particle aging, and investigate convective transport and cloud processing.

*_Standard data products_**: *

Particle type number fractions: sulfate/organic/nitrate mixtures, biomass burning, EC, sea salt, mineral dust, meteoric, alkali salts, heavy fuel combustion, and other. Sampling times range from 1-5 mins.

*_Advanced data products_**:*

Number, surface area, volume, and mass concentrations of the above particle types. Total sulfate and organic mass concentrations. Relative and absolute abundance of various chemical markers and aerosol sub-components: methanesulfonic acid, sulfate acidity, organic oxidation level, iodine, bromine, organosulfates, pyridine, and other species.

CRL can provide simultaneous water vapor, temperature, aerosol, and cloud profiles within the planetary boundary layer (PBL) from UWKA, NSF/NCAR C-130, and NOAA P-3. It uses a compact, lightweight transmitting-receiving system (12-inch telescope). Although the 50-mJ CRL laser limits water vapor measurement to short-range under high solar background conditions, past CRL measurements demonstrated that CRL measurements offer excellent measurements to characterize PBL structures from airborne platforms.   CRL enhances PBL observations at horizontal resolutions ranging from ~100 m to ~1 km and can revolutionize a range of atmospheric processes studies. These include: advancing our understanding of small-scale interactions between clouds and their environment, investigating air-sea and air-land interactions; documenting boundary layer structure over heterogeneous surfaces and under cloudy conditions; examining the mesoscale atmospheric environments and dynamics.

MARLi was an NSF-MRI funded new instrument development to provide water vapor, temperature, aerosol, and cloud profiles within the planetary boundary layer (PBL). MARLi was successfully flight-tested on the UWKA and the NSF/NCAR C-130 for over sixty-hours in the summer of 2016.  
MARLi transforms our capability to observe the atmosphere at horizontal resolutions ranging from ~100 m to ~1 km and can revolutionize a range of atmospheric processes studies. These include: advancing our understanding of small-scale interactions between clouds and their environment, investigating air-sea and air-land interactions; documenting boundary layer structure over heterogeneous surfaces and under cloudy conditions; examining the mesoscale atmospheric environments and dynamics.

CARE consists of three instruments: an Optical Particle AnaLyzer (OPAL), a second generation Cloud, Aerosol and Precipitation Spectrometer (CAPS), and a Precipitation Imaging Probe (PIP). CARE detects the size distributions of aerosol and cloud particles in the size range between 0.5 µm and 6.2 mm, provides information about particle shape and cloud phase, and allows the retrieval of refractive index of single particles in the size range between ~0.5 and 2 µm.

The Polarized Imaging Nephelometer is an in situ instrument designed and built at the Laboratory for Aerosols, Clouds and Optics (LACO) at the University of Maryland Baltimore County for the measurement of components of the aerosol phase matrix in high angular resolution between 2 to 178 deg scattering angles. The measured phase matrix provides extensive characterization of the scattering properties of the studied aerosols allowing for a very comprehensive set of aerosol scattering parameters. These measurements are essential for the validation of the new generation of aerosol remote sensors like the APS polarimeter in the Glory satellite, and for the construction of accurate models of real aerosol particles, specially the non-spherical ones.

The DASH-SP providse rapid measurements of size-resolved aerosol sub-saturated hygroscopic growth factors and the real part of aerosol refractive index. It has been deployed aboard the NASA DC-8 during the DC3 and SEAC4RS field campaigns.

Measures concentration and records images of cloud particles from approximately 50-1600 microns in diameter with a resolution of 25 microns per pixel. Measures cloud droplet and aerosol concentrations within the size range of 0.5-50 microns.

The three DMT instruments included in the CAPS are the Cloud Imaging Probe (CIP), the Cloud and Aerosol Spectrometer (CAS), and the Hotwire Liquid Water Content Sensor (Hotwire LWC).

The CIP, which measures larger particles, operates as follows. Shadow images of particles passing through a collimated laser beam are projected onto a linear array of 64 photodetectors. The presence of a particle is registered by a change in the light level on each diode. The registered changes in the photodetectors are stored at a rate consistent with probe velocity and the instrument’s size resolution. Particle images are reconstructed from individual “slices,” where a slice is the state of the 64-element linear array at a given moment in time. A slice must be stored each time interval that the particle advances through the beam a distance equal to the resolution of the probe. Optional grayscale imaging gives three levels of shadow recording on each photodetector, allowing more detailed information on the particles.

The CAS, which measures smaller particles, relies on light-scattering rather than imaging techniques. Particles scatter light from an incident laser, and collecting optics guide the light scattered in the 4° to 12° range into a forward-sizing photodetector. This light is measured and used to infer particle size. Backscatter optics also measure light in the 168° to 176° range, which allows determination of the real component of a particle’s refractive index for spherical particles.

The Hotwire LWC instrument estimates liquid water content using a heated sensing coil. The system maintains the coil at a constant temperature, usually 125 °C, and measures the power necessary to maintain this temperature. More power is needed to maintain the temperature as droplets evaporate on the coil surface and cool the surface and surrounding air. Hence, this power reading can be used to estimate LWC. Both the LWC design and the optional PADS software contain features to ensure the LWC reading is not affected by conductive heat loss.

A solar tracking Direct beam Irradiance Airborne Spectrometer (DIAS) is used for calculation of line of sight ozone and wavelength dependent aerosol optical depths.

The SP2 is a laser-induced incandescence instrument primarily used for measuring the refractory BC  (rBC) mass content of individual accumulation-mode aerosol particles. It is able to provide this data product independently of the total particle morphology and mixing state, and thus delivers detailed information not only about BC loadings, but also size distributions, even in exceptionally clean air. The instrument can also provide the optical size of individual particles containing rBC, and identify the presence of materials associated with the BC fraction (i.e. identify the rBC’s mixing state). Since its introduction in 2003, the SP2 has been substantially improved, and now can be considered a highly competent instrument for assessing BC loadings and mixing state in situ.  NOAA deploys multiple SP2s with different designs: the first was built for the WB-57F research aircraft. Two others are rack-mounted units customized at NOAA; one of the rack mounted units can be humidified, and has been deployed with a paired dry rack-mounted SP2 as the "Humidified-Dual SP2" (HD-SP2). The rack mounted units are suitable for in-cabin operations.