Gaseous deposition to snow 1. Experimental study of SO/sub 2/ and NO/sub 2/ depositon

Journal Article · Thu Aug 20 04:00:00 EDT 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JD092iD08p09779· OSTI ID:6247489

Valdez, M P; Bales, R C; Stanley, D A; Dawson, G A

A series of 48 laboratory experiments has determined depth profiles of S(IV) and S(VI) accumulation in snow exposed to 20--140 ppb SO/sub 2/ for 6-12 hours. Surface deposition velocity, calculated from the amount of sulfur taken up, divided by the gas--phase concentration, averaged 0.06 cm s/sup -1/. Snow held near -2 /sup 0/C had an average deposition velocity of 0.04 cm s/sup -1/, with new snow having a value about double that for older, metamorphosed snow (0.05 versus 0.02 cm s/sup -1/). Snow held near 0 /sup 0/C had an average deposition velocity of 0.07 cm s/sup -1/, and snow held below zero, but with surface melting due to sunlight, had a value of 0.06 cm s/sup -1/. When sunlight and temperature allowed draining of meltwater, deposition velocities were much higher (0.14 cm s/sup -1/). Deposition velocities for snow at -2 /sup 0/C were as much as 60% higher for measurements over 6 hours versus 10--12 hours. Penetration of sulfur into the snow was generally about 7 cm for colder experiments and only 4 cm for snow with more liquid water present. Uptake of SO/sub 2/ by snow is apparently determined largely by the liquid-water-to-air ratio in the snowpack. SO/sub 2/ and ozone concentrations had only small effects on deposition velocity. Most sulfur in the snow was found as S(VI), even in the absence of ozone, indicating that another oxidant is readily available, especially in new snow. Sunlight had no effect on uptake, other than increasing the liquid-water-to-air ratio by surface melting of the snow. Four measurements of NO/sub 2/ deposition to snow were also made; uptake was small, with deposition velocities averaging 0.005 cm s/sup -1/ in the dark and 0.012 cm s/sup -1/ in the sunlight. copyrightAmerican Geophysical Union 1987

• Research Organization: Department of Atmospheric Sciences, University of Arizona, Tucson
• OSTI ID: 6247489
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:D8; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
ATMOSPHERIC PRECIPITATIONS
CHALCOGENIDES
CHEMICAL COMPOSITION
DEPOSITION
MELTING
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
OZONE
PHASE TRANSFORMATIONS
POLLUTION
QUANTITY RATIO
RADIATIONS
SNOW
SOLAR RADIATION
STELLAR RADIATION
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
TEMPERATURE EFFECTS
VELOCITY