Constraining the atmospheric hydrogen budget through spatiotemporal patterns in models and observations

Atmospheric hydrogen is an important atmospheric constituent, affecting the oxidative capacity of the atmosphere and indirectly causing a climate warming effect through its chemical interactions. To quantify these effects, and that of future hydrogen emissions from anthropogenic activity, requires understanding hydrogen’s atmospheric budget. We aim to constrain this budget using spatial and temporal patterns of hydrogen, its sources, and sinks, derived from observations and a multi-model comparison.

As part of the Climate Impacts of a HYdrogen economy: the pathWAY to knowledge (HYway) project, emissions-driven simulations of present-day hydrogen have been conducted in several climate and chemistry transport models. Variation in the meridional, vertical and seasonal patterns of hydrogen concentration across these models arise due to differences in the corresponding patterns of each budget term. By comparing the hydrogen concentration patterns in observational data to that of the models and their budget terms, we attempt to constrain the magnitude of each budget term. These constraints are determined from basic statistical analysis and simple box modelling approaches.

We thus present an analysis of the spatial and temporal patterns of atmospheric hydrogen and its sources and sinks, derived from observational and model data, and estimation of the magnitude of budget terms.