In:
Atmospheric Measurement Techniques, Copernicus GmbH, Vol. 11, No. 12 ( 2018-12-20), p. 6785-6801
Abstract:
Abstract. We developed a new lightweight stratospheric air sampler (LISA). The LISA
sampler is designed to collect four bag samples in the stratosphere during a
balloon flight for CO2, CH4 and CO mole fraction
measurements. It consists of four multi-layer foil (MLF) sampling bags, a
custom-made manifold, and a diaphragm pump, with a total weight of
∼2.5 kg. A series of laboratory storage tests were performed to assess the stability
of CO2, CH4 and CO mole fractions in both MLF and Tedlar
bags. The MLF bag was chosen due to its better overall performance than the
Tedlar bag for the three species CO2, CH4 and CO.
Furthermore, we evaluated the performance of the pump under low pressure
conditions to optimize a trade-off between the vertical resolution and the
sample size. The LISA sampler was flown on the same balloon flight with an AirCore in
Sodankylä, Finland (67.368∘ N, 26.633∘ E,
179 m a.s.l.), on 26 April and 4–7 September 2017. A total of 15
stratospheric air samples were obtained during the ascent of four flights.
The sample size ranges between 800 and 180 mL for the altitude between
12 and 25 km, with the corresponding vertical resolution ranging from
0.5 to 1.5 km. The collected air samples were analysed for
CO2, CH4 and CO mole fractions, and evaluated against
AirCore retrieved profiles, showing mean differences of 0.84 ppm for
CO2, 1.8 ppb for CH4 and 6.3 ppb for CO,
respectively. High-accuracy stratospheric measurements of greenhouse gas mole fractions are
useful to validate remote sensing measurements from ground and from space,
which has been performed primarily by comparison with collocated aircraft
measurements (0.15–13 km), and more recently with AirCore
observations (0–30 km). While AirCore is capable of achieving
high-accuracy greenhouse gas mole fraction measurements, it is challenging to
obtain accurate altitude registration for AirCore measurements. The LISA
sampler provides a viable low-cost tool for retrieving stratospheric air
samples for greenhouse gas measurements that is complementary to AirCore.
Furthermore, the LISA sampler is advantageous in both the vertical resolution
and sample size for performing routine stratospheric measurements of the
isotopic composition of trace gases.
Type of Medium:
Online Resource
ISSN:
1867-8548
DOI:
10.5194/amt-11-6785-2018
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2505596-3
