Portal de Periódicos da CAPES

Speciation and rate of photochemical NO and NO 2 production in Antarctic snow

2000; American Geophysical Union; Volume: 27; Issue: 3 Linguagem: Inglês

10.1029/1999gl010885

1944-8007

A. E. Jones, Rolf Weller, Eric Wolff, Hans‐Werner Jacobi,

Atmospheric and Environmental Gas Dynamics

Measurements were made of NO and NO 2 , in controlled experiments to investigate their production from snow. Throughout a diurnal cycle, measurements were made of ambient air and air from inside a snowblock. Enhanced concentrations of NO and NO 2 (up to 15 pptv and 32 pptv respectively) were measured inside the snowblock. The production rate inside the block varied with intensity of incident radiation, and reached a maximum of 1.1×10 6 molecs/cm³/s for NO and 2.1 × 10 6 molecs/cm³/s for NO 2 . A second experiment, in which the snowblock was alternately exposed to sunlight and then shaded, confirmed that the diurnal production was driven by photochemistry rather than some other diurnally varying factor. Concentrations of nitrate in the snowblock did not change as a result of 50 hours of experiments, confirming that if nitrate is the source reservoir, it can not be rapidly depleted. Snowpack production may contribute significantly to NO x concentrations in the Antarctic lower troposphere.