| Title: |
Observational and model evidence for a prominent stratospheric influence on variability in tropospheric nitrous oxide |
| Authors: |
Nevison, Cynthia D.; Liang, Qing; Newman, Paul A.; Stephens, Britton B.; Dutton, Geoff; Lan, Xin; Commane, Roisin; Gonzalez, Yenny; Kort, Eric |
| Source: |
eISSN: 1680-7324 |
| Publication Year: |
2024 |
| Collection: |
Copernicus Publications: E-Journals |
| Description: |
The literature presents different views on how the stratosphere influences variability in surface nitrous oxide (N 2 O) and on whether that influence is outweighed by surface emission changes driven by the El Niño–Southern Oscillation (ENSO). These questions are investigated using a chemistry–climate model with a stratospheric N 2 O tracer; surface and aircraft-based N 2 O measurements; and indices for ENSO, polar lower stratospheric temperature (PLST), and the stratospheric quasi-biennial oscillation (QBO). The model simulates well-defined seasonal cycles in tropospheric N 2 O that are caused mainly by the seasonal descent of N 2 O-poor stratospheric air in polar regions with subsequent cross-tropopause transport and mixing. Similar seasonal cycles are identified in recently available N 2 O data from aircraft. A correlation analysis between the N 2 O atmospheric growth rate (AGR) anomaly in long-term surface monitoring data and the ENSO, PLST, and QBO indices reveals hemispheric differences. In the Northern Hemisphere, the surface N 2 O AGR is negatively correlated with winter (January–March) PLST. This correlation is consistent with an influence from the Brewer–Dobson circulation, which brings N 2 O-poor air from the middle and upper stratosphere into the lower stratosphere with associated warming due to diabatic descent. In the Southern Hemisphere, the N 2 O AGR is better correlated to QBO and ENSO indices. These different hemispheric influences on the N 2 O AGR are consistent with known atmospheric dynamics and the complex interaction of the QBO with the Brewer-Dobson circulation. More airborne surveys extending to the tropopause would help elucidate the stratospheric influence on tropospheric N 2 O, allowing for better understanding of surface sources. |
| Document Type: |
text |
| File Description: |
application/pdf |
| Language: |
English |
| Relation: |
https://acp.copernicus.org/articles/24/10513/2024/ |
| DOI: |
10.5194/acp-24-10513-2024 |
| Availability: |
https://doi.org/10.5194/acp-24-10513-2024; https://acp.copernicus.org/articles/24/10513/2024/ |
| Accession Number: |
edsbas.D7BF3215 |
| Database: |
BASE |