NCAR / Scripps Airborne Flask Sampler

Short Name:

Medusa

HAIS Instrument:

Manufacturer or Builder:

Britton Stephens

TABS

Description

Model:

none

Measurements Provided:

Airborne flask samples of dried air preserved for subsequent laboratory analysis. Designed for O2, CO2, Ar/N2, 13CO2, C18O16O; can be used also for other species

Typical Sampling Rates:

32 flasks per flight, flasks integrate over ~ 1 minute.

General Description:

Medusa provides the capability for collecting samples of air integrated over 25-s (1 e-fold) sample periods. 32 cryogenically dried 1.5 L air samples can be collected in glass flasks by an automated sampler that controls the flow and pressure to the flasks. As used for example in the HIPPO campaign, Medusa provided discretely-sampled comparisons for onboard in situ O₂/N₂ ratio and CO₂ measurements and unique measurements of Ar/N₂ and ¹³C, ¹⁴C, and ¹⁸O isotopes 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, about the age and source of the air sampled, and about the convective activity of the troposphere.
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. HIPPO flasks were later analyzed on a sector-magnet mass spectrometer and a LI-COR non-dispersive infrared CO₂ analyzer by the Atmospheric Oxygen Research Group at Scripps Institution of Oceanography.
- The following photograph shows the system as used during the HIPPO multi-year campaign:

Measurement Characteristics:

Overall estimate of uncertainty: variable depending on sampled species
Response time: Samples are integrated over 25 s

Contacts

Lead Contact:

Britton Stephens

Alternate Contact:

Andrew Watt

Status/Plans

Current Location:

NCAR RAF

Operational Status:

requestable, ready for deployment

Data

Deployments:

START08

HIPPO

Serial Numbers

Property Tag and/or Serial Number:

Not Available

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Manufacturer or Builder:

TABS

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