Optimal estimation of the soil uptake rate of molecular hydrogen from the Advanced Global Atmospheric Gases Experiment and other measurements

X. Xiao*, R. G. Prinn, P. G. Simmonds, L. P. Steele, P. C. Novelli, J. Huang, R. L. Langenfelds, S. O'Doherty, P. B. Krummel, P. J. Fraser, L. W. Porter, R. F. Weiss, P. Salameh, R. H. J. Wang

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

41 Citations (Scopus)

Abstract

[1] Hydrogen (H-2), a proposed clean energy alternative, warrants detailed investigation of its global budget and future environmental impacts. The magnitudes and seasonal cycles of the major ( presumably microbial) soil sink of hydrogen have been estimated from high-frequency in situ AGAGE H-2 observations and also from more geographically extensive but low-frequency flask measurements from CSIRO and NOAA-GMD using the Kalman filter in a two-dimensional (2-D) global transport model. Hydrogen mole fractions exhibit well-defined seasonal cycles in each hemisphere with their phase difference being only about 3 months. The global production rate of H-2 is estimated to be 103 +/- 10 Tg yr(-1) with only a small estimated interannual variation. Soil uptake ( 84 +/- 8 Tg yr(-1)) represents the major loss process for H-2 and accounts for 81% of the total destruction. Strong seasonal cycles are deduced for the soil uptake of H-2. The soil sink is a maximum over the northern extratropics in summer and peaks only 2 to 3 months earlier in the Northern Hemisphere than in the Southern Hemisphere. Oxidation by tropospheric OH (18 +/- 3 Tg yr(-1)) accounts for 17% of the destruction, with the remainder due to destruction in the stratosphere. The calculated global burden is 191 +/- 29 Tg, indicating an overall atmospheric lifetime of 1.8 +/- 0.3 years. Hydrogen in the troposphere ( 149 +/- 23 Tg burden) has a lifetime of 1.4 +/- 0.2 years.

Original languageEnglish
Article number07303
Number of pages15
JournalJournal of Geophysical Research: Atmospheres
Volume112
Issue numberD7
DOIs
Publication statusPublished - 3 Apr 2007

Keywords

  • HYDROXYL RADICALS
  • NONMETHANE HYDROCARBONS
  • TROPOSPHERIC OZONE
  • METHYL CHLOROFORM
  • 2 DECADES
  • H-2
  • MODEL
  • CARBON
  • BUDGET
  • CO

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