Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone
We have studied the impact of the recently observed reaction NO+HO<sub>2</sub>→HNO<sub>3</sub> on atmospheric chemistry. A pressure and temperature-dependent parameterisation of this minor channel of the NO+HO<sub>2</sub>→NO<sub>2</sub&g...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2008-07-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/8/4061/2008/acp-8-4061-2008.pdf |
| _version_ | 1818521111090954240 |
|---|---|
| author | A. Kukui N. Butkovskaya M. P. Chipperfield M. J. Evans D. Cariolle G. Le Bras |
| author_facet | A. Kukui N. Butkovskaya M. P. Chipperfield M. J. Evans D. Cariolle G. Le Bras |
| author_sort | A. Kukui |
| collection | DOAJ |
| description | We have studied the impact of the recently observed reaction NO+HO<sub>2</sub>→HNO<sub>3</sub> on atmospheric chemistry. A pressure and temperature-dependent parameterisation of this minor channel of the NO+HO<sub>2</sub>→NO<sub>2</sub>+OH reaction has been included in both a 2-D stratosphere-troposphere model and a 3-D tropospheric chemical transport model (CTM). <br><br> Significant effects on the nitrogen species and hydroxyl radical concentrations are found throughout the troposphere, with the largest percentage changes occurring in the tropical upper troposphere (UT). Including the reaction leads to a reduction in NO<sub>x</sub> everywhere in the troposphere, with the largest decrease of 25% in the tropical and Southern Hemisphere UT. The tropical UT also has a corresponding large increase in HNO<sub>3</sub> of 25%. OH decreases throughout the troposphere with the largest reduction of over 20% in the tropical UT. The mean global decrease in OH is around 13%, which is very large compared to the impact that typical photochemical revisions have on this modelled quantity. This OH decrease leads to an increase in CH<sub>4</sub> lifetime of 5%. Due to the impact of decreased NO<sub>x</sub> on the OH:HO<sub>2</sub> partitioning, modelled HO<sub>2</sub> actually increases in the tropical UT on including the new reaction. The impact on tropospheric ozone is a decrease in the range 5 to 12%, with the largest impact in the tropics and Southern Hemisphere. Comparison with observations shows that in the region of largest changes, i.e. the tropical UT, the inclusion of the new reaction tends to degrade the model agreement. Elsewhere the model comparisons are not able to critically assess the impact of including this reaction. Only small changes are calculated in the minor species distributions in the stratosphere. |
| first_indexed | 2024-12-11T01:46:44Z |
| format | Article |
| id | doaj.art-07a7eaf5d66d48cb88221c4677191444 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-11T01:46:44Z |
| publishDate | 2008-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-07a7eaf5d66d48cb88221c46771914442022-12-22T01:24:53ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242008-07-0181440614068Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozoneA. KukuiN. ButkovskayaM. P. ChipperfieldM. J. EvansD. CariolleG. Le BrasWe have studied the impact of the recently observed reaction NO+HO<sub>2</sub>→HNO<sub>3</sub> on atmospheric chemistry. A pressure and temperature-dependent parameterisation of this minor channel of the NO+HO<sub>2</sub>→NO<sub>2</sub>+OH reaction has been included in both a 2-D stratosphere-troposphere model and a 3-D tropospheric chemical transport model (CTM). <br><br> Significant effects on the nitrogen species and hydroxyl radical concentrations are found throughout the troposphere, with the largest percentage changes occurring in the tropical upper troposphere (UT). Including the reaction leads to a reduction in NO<sub>x</sub> everywhere in the troposphere, with the largest decrease of 25% in the tropical and Southern Hemisphere UT. The tropical UT also has a corresponding large increase in HNO<sub>3</sub> of 25%. OH decreases throughout the troposphere with the largest reduction of over 20% in the tropical UT. The mean global decrease in OH is around 13%, which is very large compared to the impact that typical photochemical revisions have on this modelled quantity. This OH decrease leads to an increase in CH<sub>4</sub> lifetime of 5%. Due to the impact of decreased NO<sub>x</sub> on the OH:HO<sub>2</sub> partitioning, modelled HO<sub>2</sub> actually increases in the tropical UT on including the new reaction. The impact on tropospheric ozone is a decrease in the range 5 to 12%, with the largest impact in the tropics and Southern Hemisphere. Comparison with observations shows that in the region of largest changes, i.e. the tropical UT, the inclusion of the new reaction tends to degrade the model agreement. Elsewhere the model comparisons are not able to critically assess the impact of including this reaction. Only small changes are calculated in the minor species distributions in the stratosphere.http://www.atmos-chem-phys.net/8/4061/2008/acp-8-4061-2008.pdf |
| spellingShingle | A. Kukui N. Butkovskaya M. P. Chipperfield M. J. Evans D. Cariolle G. Le Bras Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone Atmospheric Chemistry and Physics |
| title | Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone |
| title_full | Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone |
| title_fullStr | Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone |
| title_full_unstemmed | Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone |
| title_short | Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone |
| title_sort | impact of the new hno3 forming channel of the ho2 no reaction on tropospheric hno3 nox hox and ozone |
| url | http://www.atmos-chem-phys.net/8/4061/2008/acp-8-4061-2008.pdf |
| work_keys_str_mv | AT akukui impactofthenewhno3formingchanneloftheho2noreactionontropospherichno3noxhoxandozone AT nbutkovskaya impactofthenewhno3formingchanneloftheho2noreactionontropospherichno3noxhoxandozone AT mpchipperfield impactofthenewhno3formingchanneloftheho2noreactionontropospherichno3noxhoxandozone AT mjevans impactofthenewhno3formingchanneloftheho2noreactionontropospherichno3noxhoxandozone AT dcariolle impactofthenewhno3formingchanneloftheho2noreactionontropospherichno3noxhoxandozone AT glebras impactofthenewhno3formingchanneloftheho2noreactionontropospherichno3noxhoxandozone |