|
| << vorige | volgende >> |
Tijdschrift beschrijving
Alle jaargangen van het bijbehorende tijdschrift
Alle afleveringen van het bijbehorende jaargang
Alle artikelen van de bijbehorende aflevering
Details van artikel 4 van 17 gevonden artikelen
| Titel: |
Constraints on N<sub>2</sub>O budget changes since pre-industrial time from new firn air and ice core isotope measurements |
| Auteur: |
S. Bernard T. Röckmann J. Kaiser J.-M. Barnola H. Fischer T. Blunier J. Chappellaz |
| Verschenen in: |
Atmospheric chemistry and physics |
| Paginering: | Jaargang 6 (2006) nr. 2 pagina's 493-503 |
| Jaar: |
2006 |
| Inhoud: |
A historical record of changes in the N<sub>2</sub>O isotope composition is important for a better understanding of the global N<sub>2</sub>O atmospheric budget. Here we have combined measurements of trapped gases in the firn and in ice cores of one Arctic site (North GReenland Ice core Project - NGRIP) and one Antarctic site (Berkner Island). We have performed measurements of the <sup>18</sup>O and position dependent <sup>15</sup>N isotopic composition of N<sub>2</sub>O. By comparing these data to simulations carried out with a firn air diffusion model, we have reconstructed the temporal evolution of the N<sub>2</sub>O isotope signatures since pre-industrial times. The decrease observed for all signatures is consistent from one pole to the other. Results obtained from the air occluded in the ice suggest a decrease of about -2.8, -2.4, -3.2 and -1.6 for δ<sup>15</sup>N, <sup>1</sup>δ<sup>15</sup>N, <sup>2</sup>δ<sup>15</sup>N and δ<sup>18</sup>O, respectively, since 1700 AD. Firn air data imply a decrease of about -1.1, -1.2, -1.0 and -0.6 for δ<sup>15</sup>N, <sup>1</sup>δ<sup>15</sup>N, <sup>2</sup>δ<sup>15</sup>N and δ<sup>18</sup>O, respectively, since 1970 AD. These results imply consistent trends from firn and ice measurements for δ<sup>15</sup>N and δ<sup>18</sup>O. The trends for the intramolecular distribution of <sup>15</sup>N are less well constrained than the bulk <sup>15</sup>N trends because of the larger experimental error for the position dependent <sup>15</sup>N measurements. The decrease in the heavy isotope content of atmospheric N<sub>2</sub>O can be explained by the increasing importance of agriculture for the present atmospheric N<sub>2</sub>O budget. |
| Uitgever: |
Copernicus GmbH (provided by DOAJ) |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 4 van 17 gevonden artikelen
| << vorige | volgende >> |