Open AccessFactors influencing the retention of hydrogen peroxide and molecular oxygen in rime ice
Author(s) -
Snider Jefferson R.,
Huang Jun
Publication year - 1998
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/97jd02847
Subject(s) - hard rime , hydrogen peroxide , ice crystals , precipitation , materials science , hydrogen , clear ice , volatilisation , analytical chemistry (journal) , chemistry , environmental chemistry , meteorology , geology , arctic ice pack , sea ice , climatology , antarctic sea ice , physics , organic chemistry
Vertical transport of many atmospheric trace gases is modulated by retention in solid (ice phase) precipitation during the impaction and freezing (i.e., riming) of supercooled cloud droplets. Here we report field measurements of the concentrations of both hydrogen peroxide (H 2 O 2 ) and molecular oxygen (O 2 ) in rime ice. Gas retention efficiencies, defined as the ratio of the observed concentration divided by the equilibrium concentration predicted by Henry's law, are presented. Rime ice collections were conducted in a wind tunnel using 3.2‐ and 9.5‐mm impaction cylinders. Velocities were varied between 9 and 20 m/s and ice substrate temperatures were colder than −3.5°C. Averaged values of the retention efficiencies for H 2 O 2 and O 2 were 0.05 and 0.32, respectively. Also discussed are direct measurements of H 2 O 2 volatilization obtained by monitoring increases in gaseous H 2 O 2 associated with droplet impingement and freezing on an impaction grid placed upstream of a gas sampling inlet. The observed relationships between retention and the time interval between droplet impaction suggest that H 2 O 2 and O 2 are volatilized subsequent to droplet freezing and prior to burial by continued riming. A comparison of the timescales that are expected to govern retention indicates that solute diffusivities in the solidified droplets are ∼10 −12 m 2 s −1 .