 |
| Titel |
Regular, Fast and Accurate Airborne In-Situ Methane Measurements Around the Tropopause |
| VerfasserIn |
Christoph Dyroff, Armin Rauthe-Schöch, Tanja J. Schuck, Andreas Zahn |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250079874
|
|
|
|
|
|
| Zusammenfassung |
| We present a laser spectrometer for automated monthly measurements of methane (CH4)
mixing ratios aboard the CARIBIC passenger aircraft. The instrument is based on a
commercial fast methane analyzer (FMA, Los Gatos Res.), which was modified for
fully unattended employment. A laboratory characterization was performed and the
results with emphasis on the precision, cross sensitivity to H2O, and accuracy are
presented.
An in-flight calibration strategy is described, that utilizes CH4 measurements obtained
from flask samples taken during the same flights. By statistical comparison of the
in-situ measurements with the flask samples we derive a total uncetrainty estimate of
~ 3.85 ppbv (1Ïă) around the tropopause, and ~ 12.4 ppbv (1Ïă) during aircraft ascent and
descent.
Data from the first two years of airborne operation are presented that span a large part of
the northern hemispheric upper troposphere and lowermost stratosphere, with occasional
crossings of the tropics on flights to southern Africa. With its high spatial resolution and high
accuracy this data set is unprecedented in the highly important atmospheric layer of the
tropopause. |
|
|
|
|
|
|