Simultaneous Northern Hemisphere AR tracking for direct STT ozone flux comparison

Develop a methodology to simultaneously track all atmospheric rivers across the Northern Hemisphere and compute the associated dry intrusions and stratosphere-to-troposphere transport ozone flux, in order to directly compare the atmospheric-river-associated STT ozone flux to the total Northern Hemisphere STT ozone flux.

Background

The paper quantifies stratosphere-to-troposphere transport (STT) of ozone associated with atmospheric rivers (ARs) using MERRA-2 data, focusing on December events over the northeastern Pacific from 2004–2014. It computes composites and area-integrated ozone fluxes in dry intrusions trailing ARs and estimates the fraction of Northern Hemisphere (NH) STT ozone flux attributable to ARs, finding up to 13% based on regional tracking and up to ~32% by rough global extrapolation.

However, the analysis tracks only one AR at a time over the NE Pacific and relies on approximations to relate AR-associated fluxes to the NH total. To obtain a direct, comprehensive comparison of AR-associated STT ozone flux versus the total NH STT ozone flux, the authors state that simultaneous tracking of all ARs in the NH is needed, which they explicitly reserve for future work.

References

In order to compare the AR dry intrusion contribution directly to the total STT $\mathrm{O}_{3}$ flux in the NH, we would need to track all ARs in the NH simultaneously -- a specific task that we reserve for future work.

— Ozone Anomalies in Dry Intrusions Associated with Atmospheric Rivers  (2402.10205 - Hall et al., 2024) in Section o3flux_discussion (Composite STT O3 flux as a function of AR IVT and in comparison to other work)