Atmos. Chem. Phys. Discuss., 9, 14873-14899, 2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Hydrogen soil deposition at an urban site in Finland
M. Lallo, T. Aalto, J. Hatakka, and T. Laurila
Finnish Meteorological Institute, Helsinki, Finland

Abstract. Hydrogen deposition velocities (v_d) were estimated by field chamber measurements and model simulations. A closed-chamber method was used for soil deposition studies in Helsinki, Finland, at an urban park inhabited by broad-leaved trees. Radon tracer method was used to estimate the v_d in nighttime when photochemical reactions were minimal and radon gas was concentrated to shallow boundary layer due to exhalation from soil. A two-dimensional atmospheric model was used for calculation of respective v_d values and radon exhalation rate. v_d and radon exhalation rates were lower in winter than in summer according to all methods. The radon tracer method and two-dimensional model results for hydrogen deposition velocity were in the range of 0.13 mm s−1 to 0.90 mm s−1 (radon tracer) and 0.12 mm s−1 to 0.61 mm s−1 (two-dimensional). The soil chamber results for v_d were 0.00 mm s−1 to 0.70 mm s−1. Both models and chamber measurements revealed relation between one week cumulative rain sum and deposition velocity. Lower v_d values were usually measured in high soil moisture conditions. Precipitation occurring a few days before chamber measurements decreased v_d values. The snow cover also lowered v_d.

Citation: Lallo, M., Aalto, T., Hatakka, J., and Laurila, T.: Hydrogen soil deposition at an urban site in Finland, Atmos. Chem. Phys. Discuss., 9, 14873-14899, doi:10.5194/acpd-9-14873-2009, 2009.
Search ACPD
Discussion Paper
    Final Revised Paper