Conceptual Experiments to Deepen our Understanding of Sensitivities in the Hydrogen Distribution and its Impacts.

Atmospheric hydrogen sources and sinks vary greatly with latitude and season. In particular, the major sink is deposition into soils for which there is a strong seasonality and inter-hemispheric asymmetry. However, it is understood that there is a positive global warming potential (GWP) when hydrogen is oxidised in the atmosphere.

We have formulated a conceptual model based on hydrogen fluxes that were calculated in a comprehensive atmospheric chemistry simulation as part of the HECTER project. We have used this model to extensively probe the sensitivities of the GWP and distribution of hydrogen to the time of year of emissions and their latitude, and to asymmetries in the atmosphere’s oxidising capacity. Examining these sensitives helps us to understand the discrepancies between different atmospheric chemistry models and with observations, and to further constrain uncertainties in the hydrogen GWP.