Global Hawk - AFRC

The LIF-SO2 instrument detects sulfur dioxide at the single-part per trillion (ppt) level using red-shifted laser-induced fluorescence. It has operated on the WB-57 and Global Hawk aircraft in the UT/LS, as well as on the DC-8. Sulfur Dioxide is an important precursor for aerosols including nucleation of new particles globally and can be greatly enhanced in the stratosphere following explosive volcanic eruptions. An important implication of the Asian Monsoon is transport of aerosol precursors including SO2 into the lower stratosphere.

The Airborne Detector for Energetic Lightning Emissions (ADELE) detects gamma-rays and relativistic electrons associated with lightning and thunderstorm charging. The primary scientific target is terrestrial gamma-ray flashes (TGFs), brief (< 1 millisecond), extremely bright bursts of high energy radiation that have mostly been detected from satellites in low Earth orbit. TGFs are usually simultaneous with intra-cloud lightning, but only a small fraction of these lightning flashes seem to produce them. The cause of TGFs, their connection with lightning, and whether they are frequent enough to be a radiation hazard to airline passengers and crew are all unanswered questions.

ADELE is designed to study these events from close to their production site, where the signal can be much more intense than it is for the satellites 600 km away from the storm. On the AV-1 Globak Hawk in HS3, ADELE will pass above and near electrified storms in both the eyewall and rainband regions.  ADELE uses three scintillation detectors -- 5" and 1" diameter plastic scintillators and a 3" diameter lanthanum bromide scintillator.  The plastic detectors provide the ability to measure extremely high count rates without saturation, and the lanthanum bromide detector provides improved spectroscopic information on the energy distribution of the gamma rays.  All three detectors are enclosed in a single box in the interior of the Global Hawk, since the gamma radiation (100 keV up to about 50 MeV) is highly penetrating.

Hawkeye is a combination cloud particle probe. The instrument includes four probes in one.

Probe 1: The Fast Cloud Droplet Probe (FCDP) records individual particle statistics and digitizes waveform.

Probes 2-3: 2D-S 10-µm channel and 50-µm channel also trigger CPI.

Probe 4: 400 frame per second Cloud Particle Imager (CPI).

The Advanced Vertical Atmospheric Profiling System (AVAPS) is the dropsonde system for the Global Hawk. The Global Hawk dropsonde is a miniaturized version of standard RD-93 dropsondes based largely on recent MIST driftsondes deployed from balloons. The dropsonde provides vertical profiles of pressure, temperature, humidity, and winds. Data from these sondes are transmitted in near real-time via Iridium or Ku-band satellite to the ground-station, where additional processing will be performed for transmission of the data via the Global Telecommunications System (GTS) for research and operational use. The dispenser is located in zone 61 in the Global Hawk tail and is capable of releasing up to 88 sondes in a single flight.

mini-DOAS uses the Differential Optical Absorption Spectroscopy (DOAS) technique to identify and quantify trace gases using their narrow band absorptions.

This instrument studies:

1) the transport of short-lived halogenated species and their decay products to the stratosphere and the subsequent influence to the photochemistry and budget of Bromine (BrO) in the TTL.
2) the potential impact of halogen oxides to directly destroy UT/LS ozone.

32 samples/flight (ER-2); 50 samples/flight (WB57); 90 samples/flight (Global Hawk)

Updated control system with remote control capability

Fill times
–14 km 30 – 40 sec
–16 km 40 – 50 sec
–18 km 50 – 60 sec
–20 km 100 – 120 sec (estimated)

Analysis in UM lab: GC/MS; GC/FID; GC/ECD

HIRAD is a multi-frequency, hurricane imaging, interferometric single-pol passive C-band radiometer, operating from 4 GHz to 7 GHz, with both cross-track and along-track resolution that measures strong ocean surface winds through heavy rain from an aircraft or space-based platform. A one-dimensional thinned synthetic aperture array antenna is used to obtain wide-swath measurements with multiple simultaneous beams in a push-broom configuration. HIRAD features software beam forming with no moving parts, internal hot, cold, and noise diode based calibration, and continuous, gap-free imaging. Its swath width is approximately 60 degrees in either direction. There are two products: rain rate and wind speed.

The basis of the HIRAD design is the Stepped Frequency Microwave Radiometer (SFMR) that has successfully measured surface wind speed and rain rate in hurricanes from the NOAA Hurricane Research Division’s (HRD) P-3 aircraft. Unlike the SFMR that views only at nadir, the HIRAD provides wide-swath measurements between ± 40 degrees in incidence angle with a spot-beam spatial resolution of approximately 1-3 km. HIRAD would be able to provide high resolution hurricane imaging when used on an operational hurricane surveillance aircraft such as the NOAA HRD’s Gulfstream-IV.