Evidence of NOx production within or upon ice particles in the Greenland snowpack

NOx and NOy were determined in the interstitial air of surface snow and in ambient air at Summit, Greenland. NOx levels in interstitial air were 3 to >10 times those in ambient air, and were generally greater than ambient NOy levels. [NOy] in interstitial air varied diurnally in a manner consiste...

Full description

Bibliographic Details
Main Authors: Honrath, R E, Peterson, Matthew C, Guo, S, Dibb, Jack E., Shepson, P B, Campbell, Bradley M
Format: Text
Language:unknown
Published: University of New Hampshire Scholars' Repository 1999
Subjects:
Online Access:https://scholars.unh.edu/earthsci_facpub/110
https://scholars.unh.edu/cgi/viewcontent.cgi?article=1109&context=earthsci_facpub
Description
Summary:NOx and NOy were determined in the interstitial air of surface snow and in ambient air at Summit, Greenland. NOx levels in interstitial air were 3 to >10 times those in ambient air, and were generally greater than ambient NOy levels. [NOy] in interstitial air varied diurnally in a manner consistent with photochemical generation within the snowpack. These observations imply that photochemical reactions occurring within or upon the ice crystals of surface snow produced NOx from a N-reservoir compound within the snow. Average [NOX]:[HNO3] and [NOx]:[NOy] ratios in ambient air above the snow were elevated relative to other remote sites, indicating that NOx release within the snowpack may have altered NOX levels in the overlying atmospheric boundary layer. We suggest that the observed release of NOx may have been initiated by photolysis of nitrate, present in relative abundance in surface snow at Summit. Such a process may affect levels of nitrate and other compounds in surface snow, the overlying atmosphere, and glacial ice, and its potential role in cirrus cloud chemistry should be investigated.