Synonyms: 
WAS

Programmable Flask Package Whole Air Sampler

The PFP whole air sampler provides a means of automated or manual filling of glass flasks, twelve per PFP. The sampler is designed to remove excess water vapor from the sampled air and compress it without contamination into ~1-liter volumes. These flasks are analyzed at the NOAA’s Global Monitoring Division laboratory for trace gasses and at  the INSTAR’s Staple Isotope Lab laboratory for isotopes of methane. More than 60 trace gases found in the global atmosphere can be measured at mole fractions that range from parts-per-million (10-6), e.g., carbon dioxide, down to parts-per-quadrillion (10-15), e.g., HFC-365mfc.  The chemical species monitored include N2O, SF6, H2, CS2, OCS, CO2, CH4, CO, CFCs, HCFCs, HFCs, Solvents, Methyl Halides, Hydrocarbons and Perfluorocarbons.

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Medusa Whole Air Sampler

Medusa collects 32 cryogenically dried, flow and pressure controlled samples per flight. The samples are collected by an automated sampler into 1.5 L glass flasks that integrate over 25-s (1 e-fold) periods. Medusa provides discretely-sampled comparisons for onboard in situ O2/N2 ratio and CO2 measurements and unique measurements of Ar/N2 and 13C, 14C, and 18O isotopologues of CO2. The complementary measurements allow ground-truthing of onboard instrument measurements in a laboratory setting, where analysis conditions can often be more stringently controlled and carefully monitored. Isotope and argon measurements can provide additional information about land and ocean controls over the carbon cycle, and about the age and source of the air sampled.

Medusa consists of an onboard computer, two pressure controllers, two
 pumps, three multi-position selector
valves, and a host of other hardware that
control and direct the air samples. All air
is dried by passing it through traps
immersed in a -78 C dry ice bath, adjusted to match atmospheric pressure
at sea level, and then automatically isolated in a flask. Medusa flasks are analyzed on a sector-magnet mass spectrometer and a LiCor non-dispersive infrared CO2 analyzer by the Scripps O2 Program at Scripps Institution of Oceanography.

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Advanced Whole Air Sampler

90 samples/flight
–7 x 10 sample + 1 x 8 sample + 2 x 6 sample modules

New canisters/valves/manifold design/control system

Fill times
–14 km 30 – 40 sec
–16 km 40 – 50 sec
–18 km 50 – 60 sec
–20 km 100 – 120 sec (estimated)

Analysis in UM lab: GC/MS; GC/FID; GC/ECD; GC/RGD

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Whole Air Sampler

The Whole Air Sampler (WAS) collects samples from airborne platforms for detailed analysis of a wide range of trace gases. The compounds that are typically measured from the WAS includes trace gases with sources from industrial midlatitude emissions, from biomass burning, and from the marine boundary layer, with certain compounds (e.g. organic nitrates) that have a unique source in the equatorial surface ocean. The use of a broad suite of tracers with different sources and lifetimes provides powerful diagnostic information on air mass history and chemical processing that currently is only available from measurements from whole air samples. Previous deployments of the whole air sampler have shown that the sampling and analytical procedures employed by our group are capable of accessing the wide range of mixing ratios at sufficient precision to be used for tracer studies. Thus, routine measurement of species, such as methyl iodide, at <= 0.1 x 10-12 mole fraction, or NMHC at levels of a few x 10-12 mole fraction are possible. In addition to the tracer aspects of the whole air sampler measurements, we measure a full suite of halocarbon species that provide information on the role of short-lived halocarbons in the tropical UT/LS region, on halogen budgets in the UT/LS region, and on continuing increasing temporal trends of HFCs (such as 134a), HCFCs (such as HCFC 141b), PFCs (such as C2F6), as well as declining levels of some of the major CFCs and halogenated solvents. The measurements of those species that are changing rapidly in the troposphere also give direct indications of the age and origin of air entering the stratosphere.

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Whole Air Sampler

The UC-Irvine research group proposes to collect whole air samples aboard the NASA DC-8 aircraft during the 2012 campaign of the Southeast Asia Composition, Cloud, Climate Coupling Regional Study (SEAC4RS) field mission. More than 70 trace gases will be identified and quantified at our Irvine laboratory, including C2-C10 NMHCs, C1-C2 halocarbons, C1-C5 alkyl nitrates, and selected sulfur compounds. This will be achieved using our established technique of airborne whole air sampling followed by laboratory analysis using gas chromatography (GC) with flame ionization detection (FID), electron capture detection (ECD), and mass spectrometric detection (MSD). Our experimental procedures will build on those that have been successfully employed for numerous prior NASA field missions, for example PEMTropics B, TRACE-P, INTEX-A and B, and ARCTAS.

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