AIRCARB

Aircraft Carbon

1 July 2006 - 30 September 2008

Lead Scientist: Margaret Torn

Observatory: AAF (ARM Aerial Facility) - SGP (ARM Aerial Facility)

Airborne trace-gas measurements at ARM-SGP provided valuable data for addressing carbon-cycle questions highlighted by the US Climate Change Research Program and the North American Carbon Program. A set of carbon-cycle instruments and sample collection systems were added to an ARM-managed aircraft at ARM-SGP user facility. A separate (in-place) grant covered the cost of developing the instrument systems, analyzing the data, and ingesting all data to the ARM data archives. In the short-term (~1 y) we had two priorities. The first was to acquire the capability to measure continuous CO2 concentration profiles from the surface to mid-troposphere (i.e., 5-7 km). Such measurements facilitated calibration of the NASA Orbiting Carbon Observatory (OCO) and informed models to close carbon budgets. The second was to augment our flask-based collection of trace gases by sampling the NOAA flasks (e.g., for CO, CH4, and 13CO2) at more heights and by adding a sampler for 14CO2. This suite of trace gases, in combination with the CO2 profiles, provided a comprehensive data for inverse methods that infer ecosystem carbon exchange and quantify anthropogenic combustion emissions. Three other measurement systems were later included: (1) collection of large air volumes for 222Radon (as a tracer for atmospheric transport); (2) tunable diode laser for continuous CO and CH4 measurements; and (3) equipment for trapping water vapor for isotopic analysis. The latter was easiest to set up as a sampler held by a passenger. In general, having a seat available for a passenger to manually collect data would facilitate IOPs and deployment and testing of new instruments. The following airborne instruments and sampling systems for regular use began in FY05: (1) Continuous CO2 measurements using infrared gas analyzer; (2) Updated (12-flasks) version of the NOAA-CMDL flask sampling system used on the ARM aircraft; and (3) Simple 14CO2 radiocarbon flask sampler. The following airborne instruments and sampling systems were deployed for short IOPs in FY06 and FY07: (1) Large volume tedlar bags for air samples of atmospheric 222Radon; (2) Continuous CO and CH4 measurements with tunable diode laser; and (3) Manual trapping of water vapor by an aircraft passenger.