The decrease in mid-stratospheric tropical ozone since 1991
While global stratospheric O<sub>3</sub> has begun to recover, there are localized regions where O<sub>3</sub> has decreased since 1991. Specifically, we use measurements from the Halogen Occultation Experiment (HALOE) for the period 1991–2005 and the NASA Aura Microwave Limb...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2015-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/15/4215/2015/acp-15-4215-2015.pdf |
| _version_ | 1818241829985845248 |
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| author | G. E. Nedoluha D. E. Siskind A. Lambert C. Boone |
| author_facet | G. E. Nedoluha D. E. Siskind A. Lambert C. Boone |
| author_sort | G. E. Nedoluha |
| collection | DOAJ |
| description | While global stratospheric O<sub>3</sub> has begun to recover, there are localized
regions where O<sub>3</sub> has decreased since 1991. Specifically, we use
measurements from the Halogen Occultation Experiment (HALOE) for the period
1991–2005 and the NASA Aura Microwave Limb Sounder (MLS) for the period
2004–2013 to demonstrate a significant decrease in O<sub>3</sub> near
~ 10 hPa in the tropics. O<sub>3</sub> in this region is very
sensitive to variations in NO<sub><i>y</i></sub>, and the observed decrease can be
understood as a spatially localized, yet long-term increase in NO<sub><i>y</i></sub>. In
turn, using data from MLS and from the Atmospheric Chemistry Experiment
(ACE), we show that the NO<sub><i>y</i></sub> variations are caused by decreases in
N<sub>2</sub>O which are likely linked to long-term variations in dynamics. To
illustrate how variations in dynamics can affect N<sub>2</sub>O and O<sub>3</sub>, we
show that by decreasing the upwelling in the tropics, more of the N<sub>2</sub>O
can photodissociate with a concomitant increase in NO<sub><i>y</i></sub> production (via
N<sub>2</sub>O + O(<sup>1</sup>D) → 2NO) at 10 hPa. Ultimately, this can cause an
O<sub>3</sub> decrease of the observed magnitude. |
| first_indexed | 2024-12-12T13:35:34Z |
| format | Article |
| id | doaj.art-a634fb5edce944ff88a067e7419fc5d0 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-12T13:35:34Z |
| publishDate | 2015-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-a634fb5edce944ff88a067e7419fc5d02022-12-22T00:22:58ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242015-04-011584215422410.5194/acp-15-4215-2015The decrease in mid-stratospheric tropical ozone since 1991G. E. Nedoluha0D. E. Siskind1A. Lambert2C. Boone3Naval Research Laboratory, Washington, D. C., USANaval Research Laboratory, Washington, D. C., USAJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USADepartment of Chemistry, University of Waterloo, Waterloo, Ontario, CanadaWhile global stratospheric O<sub>3</sub> has begun to recover, there are localized regions where O<sub>3</sub> has decreased since 1991. Specifically, we use measurements from the Halogen Occultation Experiment (HALOE) for the period 1991–2005 and the NASA Aura Microwave Limb Sounder (MLS) for the period 2004–2013 to demonstrate a significant decrease in O<sub>3</sub> near ~ 10 hPa in the tropics. O<sub>3</sub> in this region is very sensitive to variations in NO<sub><i>y</i></sub>, and the observed decrease can be understood as a spatially localized, yet long-term increase in NO<sub><i>y</i></sub>. In turn, using data from MLS and from the Atmospheric Chemistry Experiment (ACE), we show that the NO<sub><i>y</i></sub> variations are caused by decreases in N<sub>2</sub>O which are likely linked to long-term variations in dynamics. To illustrate how variations in dynamics can affect N<sub>2</sub>O and O<sub>3</sub>, we show that by decreasing the upwelling in the tropics, more of the N<sub>2</sub>O can photodissociate with a concomitant increase in NO<sub><i>y</i></sub> production (via N<sub>2</sub>O + O(<sup>1</sup>D) → 2NO) at 10 hPa. Ultimately, this can cause an O<sub>3</sub> decrease of the observed magnitude.http://www.atmos-chem-phys.net/15/4215/2015/acp-15-4215-2015.pdf |
| spellingShingle | G. E. Nedoluha D. E. Siskind A. Lambert C. Boone The decrease in mid-stratospheric tropical ozone since 1991 Atmospheric Chemistry and Physics |
| title | The decrease in mid-stratospheric tropical ozone since 1991 |
| title_full | The decrease in mid-stratospheric tropical ozone since 1991 |
| title_fullStr | The decrease in mid-stratospheric tropical ozone since 1991 |
| title_full_unstemmed | The decrease in mid-stratospheric tropical ozone since 1991 |
| title_short | The decrease in mid-stratospheric tropical ozone since 1991 |
| title_sort | decrease in mid stratospheric tropical ozone since 1991 |
| url | http://www.atmos-chem-phys.net/15/4215/2015/acp-15-4215-2015.pdf |
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