NCAR’s Gulfstream V jet made its first flight during T-Rex.  Scientists aboard will collect data at the tops of storms and lower edge of the stratosphere, altitudes out of reach of most research aircraft. The aircraft’s range will enable scientists to survey remote ocean regions in a single flight to learn more about interactions between the oceans and atmosphere.

Installing the Initial Instrument Suite and Beginning Operations for the NSF/NCAR Gulfstream-V (G-V) [highlight]

2006 heralded the debut of nation's most advanced research aircraft, NCAR's G-V. This cutting edge observational platform will meet the scientific needs of many disciplines and user communities, focusing on Chemistry and Climate, Chemical Cycles, Studies of the Upper Troposphere/Lower Stratosphere, Air Quality, and Mesoscale Weather. After an initial instrument upload period in early FY 2006, five small research projects were supported under the umbrella of the Progressive Science flight program. Following the Progressive Science missions, the aircraft was configured to support the Terrain-Induced Rotor Experiment (T-REX). The successful completion of these programs showcased new capabilities the G-V brings to the scientific community and demonstrated a new and exciting paradigm for conducting airborne research.

1. Progressive Science Missions
2. T-Rex Campaign
3. Improving the G-V Capabilities
4. G-V Instrumentation and Development
1. HAIS
2. HIAPER Cloud Radar

Progressive Science Missions

Late 2005 led off with Progressive Science flights designed to test the capabilities of the new aircraft while supporting a group of initial science projects. EOL was able to take advantage of the satellite communications and networking capabilities installed on the G-V by feeding aircraft data streams into existing tools like Google Maps, Google Earth, and the “aeros” display program developed by EOL's Computing, Data and Software Facility. Real-time access to the flight tracks and in situ measurements was just a mouse click away.  Scientists and students, on the ground at NCAR or at their home institutions, participated in the direction of the aircraft and helped shape the missions during these projects.

T-Rex Campaign

The primary research area for the T-Rex Campaign was 900 miles from the G-V home base at the Jefferson County (Jeffco) Airport. The airplane demonstrated the utility of its range as it was based at Jeffco for the duration of the project, resulting in significant efficiencies in project support and cost containment.

The G-V flew at altitudes of up to 45,000 feet, through waves in the upper troposphere and lower stratosphere. It joined aircraft from the University of Wyoming and the United Kingdom, which flew at lower elevations and gave scientist additional views of the mountain waves, rotors and valley phenomena. Researchers on the G-V released dropsondes to collect data on the rotors and mountain waves, and the aircraft also carried an array of trace-gas sensors that helped track air parcels as they moved through the waves. One of the surprises was that the G-V encountered less turbulence at high altitudes than forecast by models, especially during cases when strong wave breaking was predicted.

Improving the G-V Capabilities

Two significant upgrade efforts are scheduled for the G-V in 2007:

• Oct-Jan 07: install under-wing pylons and canisters and modify the airframe to accept some of the early "HAIS" (HIAPER Airborne Instrumentation Solicitation) instruments being developed for the G-V; and
• July-Sept 07: install the large (20-inch diameter) under-wing pods, the large windows, and the instrument cooling system.

The available HAIS instruments will be installed and test-flown in January 2007, along with other supplementary instruments being developed at NCAR.

To accomplish the above tasks on a certified aircraft will require interaction with the aircraft manufacturer regarding possible effects on performance, substantial engineering and construction efforts, and working with the FAA at each step. The modifications to the aircraft will require that we meet the requirements for obtaining a Supplemental Type Certificate (STC). As a result of these projects, we will be able to include instruments designed for standard instrument canisters, to include large instruments such as the HIAPER Cloud Radar in under-wing pods, to make radiation measurements from sensors mounted on the upper tail surface and below the aircraft, and to operate optical instruments that view through large windows. These upgrades therefore move us much closer to being able to realize the designed capabilities of the aircraft for accommodating comprehensive suites of instruments for research projects.

Instrumentation Development

There are three categories of instrumentation on the G-V: The “HAIS” instruments developed under UCAR contracts after investigators were selected in response to a special NSF solicitation, the “GAP” instruments being developed at NCAR to add key components not included among the HAIS projects, and the state-parameter instrumentation installed soon after delivery of the aircraft to provide basic and routine measurement capabilities.

HAIS Instrumentation

The HAIS instruments are being developed by groups outside NCAR/EOL for delivery and operation on the G-V. In FY2007, we expect to receive delivery of eleven of these instruments, some quite complex in nature, so acceptance and testing of these instruments will be a major commitment during this year. Two test-flight periods are planned, the first in January 2007 (discussed above) and the second sometime in the fall of 2007. These will be   opportunities to determine if the instruments can operate as designed on the aircraft, can meet certification requirements, and so can be accepted from the developers.

GAP instrumentation

The second set of instrument-development projects is being conducted within EOL. Thirteen instruments being developed or purchased include sensors for: water vapor (TDL), condensed water content, icing rate, cloud droplet size distribution, aerosol size distributions, an all-weather gust pod for wind measurement, a laser velocimeter, and a counterflow virtual impactor. These will all be installed and tested on the G-V in FY2007.

The largest “GAP” project being undertaken at NCAR/EOL is the design and fabrication of a pod-based, single wavelength (W-band) Doppler radar system suitable for deployment on the G-V. The radar is planned to reside in one of the new 20”-diameter “NCAR” under-wing pods and will serve in both cloud microphysics and cloud dynamics studies. The project deliverables are a W-band radar system capable of functioning in a HIAPER wing pod and complete system documentation. This documentation will include copies of all specifications, schematic diagrams, parts lists, mechanical drawings and engineering analyses.
In FY06, EOL staff prepared the preliminary design document and presented the design at the 2006 IEEE International Geoscience and Remote Sensing Symposium (IGARSS) held in Denver, CO during a special “NCAR Town Hall Meeting” session in August, 2006. A revised design document was presented at the PDR in mid-August that was attended by 15 engineers and scientists, of which 7 were from institutions outside NCAR.

The radar is expected to be completed by June 2008. For FY’07, the following activities are planned:

• 1. Write sub-system specifications for key components including the antenna, radome, and transmitter. Use these specifications as part of the procurement process.
• 2. Define and document all required signals, both internal and external to the radar, and identify connectors and wiring.
• 3. Hold a Critical Design Review, prior to procurement of parts – milestone December 2006.
• 4. Complete the detailed design of the radar receiver/exciter.

Parts of this report were previously published in the UCAR Quarterly, Spring 2006.