Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub>
<p>Several global modelling studies have explored the effects of lightning-generated nitrogen oxides (LNO<span class="inline-formula"><sub><i>x</i></sub></span>) on gas-phase chemistry and atmospheric radiative transfer, but few have quantified LNO...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2024-12-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/24/14005/2024/acp-24-14005-2024.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850251398597312512 |
|---|---|
| author | A. K. Luhar A. C. Jones J. M. Wilkinson J. M. Wilkinson |
| author_facet | A. K. Luhar A. C. Jones J. M. Wilkinson J. M. Wilkinson |
| author_sort | A. K. Luhar |
| collection | DOAJ |
| description | <p>Several global modelling studies have explored the effects of lightning-generated nitrogen oxides (LNO<span class="inline-formula"><sub><i>x</i></sub></span>) on gas-phase chemistry and atmospheric radiative transfer, but few have quantified LNO<span class="inline-formula"><sub><i>x</i></sub></span>'s impact on aerosol, particularly when nitrate aerosol is included. This study addresses two key questions: (1) how does including nitrate aerosol affect properties such as tropospheric composition, and (2) how do these effects depend on lightning parameterisation and LNO<span class="inline-formula"><sub><i>x</i></sub></span> levels? Using the Met Office's Unified Model–United Kingdom Chemistry and Aerosol (UM–UKCA) global chemistry–climate model, which now includes a modal nitrate aerosol scheme, we investigate these effects with two lightning-flash-rate parameterisations. Our findings show that both nitrate aerosol and LNO<span class="inline-formula"><sub><i>x</i></sub></span> significantly impact tropospheric composition and aerosol responses. Including nitrate aerosol reduces global mean tropospheric OH by 5 %, decreases the tropospheric ozone burden by 4 %–5 %, increases methane lifetime by a similar amount, and alters the top-of-atmosphere (TOA) net downward radiative flux by <span class="inline-formula">−0.4</span> W m<span class="inline-formula"><sup>−2</sup></span>. The inclusion of nitrate also shifts the aerosol size distribution, particularly in the Aitken and accumulation modes. A 5.2 Tg N yr<span class="inline-formula"><sup>−1</sup></span> increase in LNO<span class="inline-formula"><sub><i>x</i></sub></span> from a zero baseline results in global aerosol increases of 2.8 % in NH<span class="inline-formula"><sub>4</sub></span>, 4.7 % in fine NO<span class="inline-formula"><sub>3</sub></span>, 12 % in coarse NO<span class="inline-formula"><sub>3</sub></span>, and 5.8 % in SO<span class="inline-formula"><sub>4</sub></span> mass burdens. This much LNO<span class="inline-formula"><sub><i>x</i></sub></span> increase causes relatively small positive changes in aerosol optical depth, TOA radiative flux, and cloud droplet number concentration compared to when nitrate is included. The results, based on a fast uptake rate for HNO<span class="inline-formula"><sub>3</sub></span> to produce NH<span class="inline-formula"><sub>4</sub></span>NO<span class="inline-formula"><sub>3</sub></span>, likely represent an upper limit on nitrate effects.</p> |
| format | Article |
| id | doaj-art-52fc852c80f24ffeb692cea58a564574 |
| institution | OA Journals |
| issn | 1680-7316 1680-7324 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj-art-52fc852c80f24ffeb692cea58a5645742025-08-20T01:57:54ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242024-12-0124140051402810.5194/acp-24-14005-2024Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub>A. K. Luhar0A. C. Jones1J. M. Wilkinson2J. M. Wilkinson3CSIRO Environment, Aspendale, Victoria 3195, AustraliaMet Office, Fitzroy Road, Exeter, EX1 3PB, UKMet Office, Fitzroy Road, Exeter, EX1 3PB, UKnow at: Forecast Department, European Centre for Medium-Range Weather Forecasts, Reading, RG2 9AX, UK<p>Several global modelling studies have explored the effects of lightning-generated nitrogen oxides (LNO<span class="inline-formula"><sub><i>x</i></sub></span>) on gas-phase chemistry and atmospheric radiative transfer, but few have quantified LNO<span class="inline-formula"><sub><i>x</i></sub></span>'s impact on aerosol, particularly when nitrate aerosol is included. This study addresses two key questions: (1) how does including nitrate aerosol affect properties such as tropospheric composition, and (2) how do these effects depend on lightning parameterisation and LNO<span class="inline-formula"><sub><i>x</i></sub></span> levels? Using the Met Office's Unified Model–United Kingdom Chemistry and Aerosol (UM–UKCA) global chemistry–climate model, which now includes a modal nitrate aerosol scheme, we investigate these effects with two lightning-flash-rate parameterisations. Our findings show that both nitrate aerosol and LNO<span class="inline-formula"><sub><i>x</i></sub></span> significantly impact tropospheric composition and aerosol responses. Including nitrate aerosol reduces global mean tropospheric OH by 5 %, decreases the tropospheric ozone burden by 4 %–5 %, increases methane lifetime by a similar amount, and alters the top-of-atmosphere (TOA) net downward radiative flux by <span class="inline-formula">−0.4</span> W m<span class="inline-formula"><sup>−2</sup></span>. The inclusion of nitrate also shifts the aerosol size distribution, particularly in the Aitken and accumulation modes. A 5.2 Tg N yr<span class="inline-formula"><sup>−1</sup></span> increase in LNO<span class="inline-formula"><sub><i>x</i></sub></span> from a zero baseline results in global aerosol increases of 2.8 % in NH<span class="inline-formula"><sub>4</sub></span>, 4.7 % in fine NO<span class="inline-formula"><sub>3</sub></span>, 12 % in coarse NO<span class="inline-formula"><sub>3</sub></span>, and 5.8 % in SO<span class="inline-formula"><sub>4</sub></span> mass burdens. This much LNO<span class="inline-formula"><sub><i>x</i></sub></span> increase causes relatively small positive changes in aerosol optical depth, TOA radiative flux, and cloud droplet number concentration compared to when nitrate is included. The results, based on a fast uptake rate for HNO<span class="inline-formula"><sub>3</sub></span> to produce NH<span class="inline-formula"><sub>4</sub></span>NO<span class="inline-formula"><sub>3</sub></span>, likely represent an upper limit on nitrate effects.</p>https://acp.copernicus.org/articles/24/14005/2024/acp-24-14005-2024.pdf |
| spellingShingle | A. K. Luhar A. C. Jones J. M. Wilkinson J. M. Wilkinson Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub> Atmospheric Chemistry and Physics |
| title | Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub> |
| title_full | Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub> |
| title_fullStr | Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub> |
| title_full_unstemmed | Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub> |
| title_short | Quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning NO<sub><i>x</i></sub> |
| title_sort | quantifying the impact of global nitrate aerosol on tropospheric composition fields and its production from lightning no sub i x i sub |
| url | https://acp.copernicus.org/articles/24/14005/2024/acp-24-14005-2024.pdf |
| work_keys_str_mv | AT akluhar quantifyingtheimpactofglobalnitrateaerosolontroposphericcompositionfieldsanditsproductionfromlightningnosubixisub AT acjones quantifyingtheimpactofglobalnitrateaerosolontroposphericcompositionfieldsanditsproductionfromlightningnosubixisub AT jmwilkinson quantifyingtheimpactofglobalnitrateaerosolontroposphericcompositionfieldsanditsproductionfromlightningnosubixisub AT jmwilkinson quantifyingtheimpactofglobalnitrateaerosolontroposphericcompositionfieldsanditsproductionfromlightningnosubixisub |