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 H 2 on soil, v d , which explicitly describes the dependence of v d 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 H 2 removal, and a moist deeper layer with a uniform H 2 removal rate constant. The dependence of δ on is derived from modelled vertical profiles of Θ w . The resulting dependence of v d on is compared to the previously used v d ( ) derived from a single-layer model, i.e. one without a dry top layer, and with a set of v d from field measurements. The implications are discussed.