Deposition velocity of H2: a new algorithm for its dependence on soil moisture and temperature

We derive an analytical expression for the deposition velocity of H2 on soil, vd, which explicitly describes the dependence of vd on the average soil moisture, and temperature, T. It is based on the solution of the equation for vertical diffusion in a two-layer soil model consisting of a dry top layer of a depth, δ, free of H2 removal, and a moist deeper layer with a uniform H2 removal rate constant. The dependence of δ on is derived from modelled vertical profiles of Θw. The resulting dependence of vd on is compared to the previously used vd() derived from a single-layer model, i.e. one without a dry top layer, and with a set of vd from field measurements. The implications are discussed.