Global Monitoring Division - ESRL-GMD
This story entered on 19th Sep, 2011 10:25:32 AM PST
The AirCore is a near-full column atmospheric sampling system, invented and patented by Dr. Pieter Tans of the Global Monitoring Division at NOAA/ESRL in Boulder, Colorado, and funded by NOAA's Unmanned Aircraft Systems program. The AirCore sampler is a long coil of stainless steel tubing that ascends on a helium balloon and fills with surrounding atmosphere during a parachute-controlled descent, collecting a sample from balloon burst (up to 100,000 ft) down to ground level, representing 99% of the atmosphere. The small and simple design of the AirCore makes it significantly more affordable and easier to deploy than other methods, such as glass flasks or heavy gas analyzers, which are very expensive to send to stratospheric altitudes. More information: http://www.esrl.noaa.gov/gmd/ccgg/aircraft/aircore.html
An AirCore sample can be analyzed in the laboratory for concentrations of trace atmospheric gases. The length of the tubing and short time to analysis minimizes mixing inside the tubing, so that each AirCore sample provides up to 100 measurements of carbon dioxide (CO2¬), methane (CH4), and carbon monoxide (CO) from top altitude to ground level. This is a much denser array of measurements than possible using comparable methods. These measurements are calibrated on the World Meteorological Organization scales (within 0.05% for CO2 and CH4, 5% for CO) and provide a ground-truth standard for comparison with total column measurements from either ground-based Fourier Transfer Spectrometers or satellites. A comparison of these in-situ measurements with spectral methods will be crucial to the calibration of satellites such as NASA’s Orbiting Carbon Observatory-2, scheduled to begin making CO2 measurements around the globe in 2013.
On September 10, 2011, NOAA and CIRES scientists and engineers teamed up with the non-profit group Edge of Space Sciences (EOSS) to launch three AirCore samplers of varying sizes and material coatings. The resulting data set shows excellent agreement between the three samples for CO2, CH4, and CO, and also characterizes some regions of atmospheric variability. The balloons had different burst altitudes ranging from 25 to 30 km (82,000 to 99,000 ft) and varied in their descent locations by 5 to 10 km (3 to 6 miles). These launches further demonstrate the capability of the AirCore to obtain precise and accurate near-full column measurements that can be compared with satellite measurements as well as provide stratospheric measurements of trace gases in a much more affordable and routine fashion than ever before.
Name: Anna Karion
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