Post-depositional modification of NO(-)3 in snow layers at East Antarctica and at the headwater of Urumqi River
Acidic species, such as Nitrate, in polar snow and firn layers are "reversibly" deposited, and are sufficiently volatile to undergo significant post-depositional exchange between snow/firn and the atmosphere. Through comparison of the snowpit and snowpack nitrate concentrations from centra...
| Main Authors: | , , , |
|---|---|
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Polar Research Institute of China - PRIC
2000
|
| Subjects: | |
| Online Access: | http://library.arcticportal.org/2193/ http://library.arcticportal.org/2193/1/A200001002.pdf |
| Summary: | Acidic species, such as Nitrate, in polar snow and firn layers are "reversibly" deposited, and are sufficiently volatile to undergo significant post-depositional exchange between snow/firn and the atmosphere. Through comparison of the snowpit and snowpack nitrate concentrations from central East Antarctica and the headwater of Urumqi River, we conclude that the nitrate peaks in the uppermost surface snow layers in central Antarctica are not related to an atmospheric signal and must account for post-depositional effects. Such effects, however, are not found in the surface snowpack nitrate profiles from the headwater of Urumqi River. Two reasons may account for the post-depositional difference. At first, nitrate in the polar snow and firn layers appears to be hydrated ion, which can be taken up by the atmosphere, while at the headwater of Urumqi River it seems mainly as mineral ion, which assembles the behavior of aerosol-derived species that are "irreversibly" deposited and do not undergo significant post-depositional exchange with the atmosphere. Secondly, the chemical features of the snow and ice on the Antarctica are mainly determined by wet deposition, to the contrary, dry deposition is more significant at the headwater of Urumqi River than that on the East Antarctic Plateau |
|---|