P-3 Orion - WFF

Vapor In-cloud Profiling Radar (VIPR), provides high-vertical-resolution water vapor soundings within the PBL. Importantly, VIPR implements for the first time the differential absorption radar (DAR) approach to provide sounding within the cloudy and precipitating volumes.

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.

SPEC has developed a Fast Cloud Droplet Probe (FCDP) with state-of-the-art electro-optics and electronics that utilizes forward scattering to determine cloud droplet distributions and concentrations in the range of 1.5 to 50 microns.  Though designed for cloud droplet measurements, the probe has also shown reliable measurements in ice clouds.  The new electronics include a temperature controlled fiber-coupled laser, FSSP-300 optics with pinhole limiting depth of field (Lance et al. 2010), a field programmable gate array (FPGA), 40 MHz analog-to-digital-converter (ADC) sampling, custom amplifiers, a very small and low power Linux based 400 MHz processor and a 16-Gigabyte flash drive that stores data at the probe.

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.

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.

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.).

Targeting Fourier Transform Spectrometer (FTS) measuring infrared spectra from 4.5 to 13.4 µm. AES was the airborne testbed for the EOS/Aura TES instrument and operated ~1994-2000.

The APR-3 is a three frequency (13, 35, and 94 GHz), Doppler, dual-polarization radar system. It has a downward looking antenna that performs cross track scans, covering a swath that is +/- 25 to each side of the aircraft path. Additional features include: simultaneous dual-frequency, matched beam operation, simultaneous measurement of both like- and cross-polarized signals at both frequencies, Doppler operation, and real-time pulse compression (calibrated reflectivity data can be produced for large areas in the field during flight, if necessary).