SOFIA flight pattern: SOFIA will mostly sample the tropopause region of the Earth atmosphere at
cruise altitude, and initially along many profiles in and out of Northern California. SOFIA will fly about 4 times a week about 8-10 hours. At the beginning, these flights will usually
take off around 9 p.m. and land around 5 a.m., out of Moffett Field, CA.
The flight directions are random, but a significant
proportion of the flights will head northwest, over the
northern Pacific. In special circumstances it is possible that part of a flight could be in daylight, but in general there will only be night flights, and
sometimes takeoffs and landings will occur around sunset or sunrise. This last point is especially true for summer flights since the nights are about the same length of time as a typical mission. However, there will be little or no time at altitude (37,000 feet and higher) with the sun above the horizon.
The flight legs may be anywhere from about 20
minutes to as much as 4 hours long, and are almost always curved
(arcs) to follow the rotation of the celestial sphere. The altitudes
will start usually at 39,000 feet and climb to 41,000 and often
higher as fuel is burned off. There will be a 2-month deployment to
New Zealand for southern sky viewing every year after the first
couple of years.
This flight pattern is well suited for Earth Science research. Observations from the Upper Deck on SOFIA could help answer key science questions and issues as defined in the Earth Science Enterprise Strategic Plan.
Earth Sciences Fundamental Questions :
Potential contributions of measurements based on the SOFIA Upper Deck to the following programs:
- How is the Earth changing and what are the consequences for life on Earth?
- How is the global Earth system changing?
- What are the primary causes of change in the Earth system?
- How does the Earth system respond to natural and human-induced changes?
- How will the Earth system change in the future?
Beyond Earth Sciences, a SOFIA Upper Deck Research Facility could contribute to the following questions as well:
- the Global Water and Energy Cycle
- the Carbon cycle
- Atmospheric Chemistry
- Weather and Short-Term Climate Forecasting
- Long-Term climate Change
- Geodynamics and Other Solid Earth Activities
- Astrobiology Fundamental Question "What is the future of life on Earth and beyond?"
- Astrobiology Goal 6 - "Understand the principles that will shape the future of life, both on Earth and beyond. Elucidate the drivers and effects of ecosystem change as a basis for projecting likely future changes on timescales ranging from decades to millions of years"
- Sun Earth Connections Roadmap Quest II - How do the Earth and planets respond? Solar interactions with the Earth's Atmosphere and Space Environment. Comparative Space Environment."
- Sun Earth Connections Roadmap Quest III - "What are the impacts for humanity? Space Weather, changes of Earth's atmosphere, habitability of Space"
Upper Troposphere Lower Stratosphere (UTLS):
SOFIA will fly frequently through the tropopause, with a cruising altitude in the lower stratosphere. Key issues in this region of the atmosphere are:
The graph below is adapted from Stohl et al. (JGR, Vol. 108, No. D12, 8516, 2003).
- Stratosphere-Troposphere Exchange occurs frequently, but models fail to correctly reproduce it.
- What drives water vapor concentration in the stratosphere?
- What chemistry occurs in the tropopause? What is the influence of convective influence and how does it affect the radical and ozone budgets?
- What are the radiation properties of thin clouds and aerosols. What chemical reactions occur on the surfaces of these clouds?
Gas and aerosol collection:
Aerosol collection and gas sampling are possible over long time baselines for studies of global climate change. SOFIA gives the opportunity to monitor gases at nighttime, important for odd-nitrogen chemistry.
Polar Mesospheric Clouds:
Polar mesospheric clouds (PMC), also known as noctilucent clouds, are created by ice crystals in the mesosphere. Observation from aircraft would allow the identification of PMC structure over spatial scales not possible from the ground and not yet done by spacecraft. By determining the variation in the cloud brightness with viewing angle we can infer the size of the scattering particles. The airborne observations will also add to the science attempted through the NASA AIM satellite intended for the study of PMCs and planned for launch in September 2006.
Airglow and gravity waves:
Gravity wave structure in OH airglow can be observed over long baselines and long timescales.
Other science objectives may well be achieved, the topic of discussion at the first SOFIA Upper Deck Science Opportunities Workshop (June 22-23, 2004).