HIPPO Global Phase I

The “Collaborative Research: HIAPER Pole-to-Pole Observations (HIPPO) of Carbon Cycle and Greenhouse Gases Study” will measure cross sections of atmospheric concentrations approximately pole-to-pole, from the surface to the tropopause, five times during different seasons over a three year period. A comprehensive suite of atmospheric trace gases pertinent to understanding the Carbon Cycle will be measured. HIPPO will transect the mid-Pacific ocean and return either over the Eastern Pacific, or over the Western Atlantic. The program will provide the first comprehensive, global survey of atmospheric trace gases, covering the full troposphere in all seasons and multiple years. EOL will provide the NSF/NCAR G-V for this project, and the PI is Prof. Steve Wofsy from Harvard University.

This phase of the HIPPO project is the first one of five. The next phase will take place in November 2009.

To accomplish the HIPPO objectives, the aircraft will fly the following missions:

• Rocky Mountain Metropolitan Airport, CO, USA -> Anchorage, AK, USA
• Anchorage, AK to the North Pole (up to 85 degrees North) round trip
• Anchorage, AK, USA -> Honolulu, HI, USA
• Honolulu, HI, USA -> Pago Pago, American Samoa
• Pago Pago, American Samoa -> Christchurch, NZ
• Christchurch, NZ -> South Pole (up to 67 degrees South) round trip
• Christchurch, NZ -> Papeete, Tahiti
• Papiete, Tahiti -> Easter Island, Chile
• Easter Island, Chile -> San Jose, CR
• San Jose, CR -> Rocky Mountain Metropolitan Airport, CO, USA

This route is 44,700 km (27,760 miles, 24,200 nautical miles) long and took 21 days. Images below (courtesy of Google, GoogleEarth project) show the actual GV tracks.

All of the flights are essentially direct point-to-point routes with ongoing altitude changes. It is planned to have two maximum altitude ascents per flight, one in the first half and one in the second half, depending on the ability of the ATC to support altitude changes. Most of the flight will be conducted below RVSM (29,000 - 27,000 ft in different FIRs) in order to allow the GV to go up and down constantly to collect data at different altitudes throughout the troposphere. Ideally the flight would take off and go to FL430 for 15 min, then descend below RVSM and proceed in a sawtooth pattern between FL270 and FL50 with a 1,500 ft/min climb/ascent rate, then climb to FL450 near the end of the flight for about 15 min, descend below RVSM again and proceed to the airport.

All flights will be followed by at least one no-flight, maintenance day and may be followed by a rest day ("hard down" day); see the operations schedule for details.