Age of stratospheric air is a well established metric for the stratospheric transport circulation.
Rooted in a robust theoretical framework, this approach offers the benefit of being deducible …

The age of air is an important transport diagnostic that can be derived from trace gas
measurements and compared to global chemistry climate model output. We describe a new …

We have developed in situ and flask sampling systems for airborne measurements of
variations in the O 2/N 2 ratio at the part per million level. We have deployed these …

Fossil fuels contain small amounts of helium, which are co-released into the atmosphere
together with carbon dioxide. However, a clear build-up of helium in the atmosphere has not …

We analyzed air samples collected on board a C-130 cargo aircraft over the western North
Pacific from May 2012 to March 2020 for atmospheric δ (O 2/N 2) and CO 2 amount fraction …

The upper troposphere and lower stratosphere (UTLS) region during the summer monsoon
season over North America (NAM) is influenced by the transport of air from a variety of …

The circulation of the stratosphere transports important trace gases, including ozone, and
can be thought of as having a fast horizontal mixing component and a slow meridional …

Systematic measurements of the atmospheric Ar/N 2 ratio have been made at ground-based
stations in Japan and Antarctica since 2012. Clear seasonal cycles of the Ar/N 2 ratio with …

Tropospheric helium variations are tightly linked to CO 2 due to the co-emission of He and
CO 2 from natural-gas burning. Recently, Birner et al.(2022a) showed that the global …

The atmospheric He/N 2 ratio is expected to increase due to the emission of He associated
with fossil fuels and is expected to also vary in both space and time due to gravitational …