WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe
Chemical modelling studies have been conducted over north-western Europe in summer conditions, showing that night-time dinitrogen pentoxide (N<sub>2</sub>O<sub>5</sub>) heterogeneous reactive uptake is important regionally in modulating particulate nitrate a...
| Main Authors: | , , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-02-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/15/1385/2015/acp-15-1385-2015.pdf |
| _version_ | 1817993531363426304 |
|---|---|
| author | D. Lowe S. Archer-Nicholls W. Morgan J. Allan S. Utembe B. Ouyang E. Aruffo M. Le Breton R. A. Zaveri P. Di Carlo C. Percival H. Coe R. Jones G. McFiggans |
| author_facet | D. Lowe S. Archer-Nicholls W. Morgan J. Allan S. Utembe B. Ouyang E. Aruffo M. Le Breton R. A. Zaveri P. Di Carlo C. Percival H. Coe R. Jones G. McFiggans |
| author_sort | D. Lowe |
| collection | DOAJ |
| description | Chemical modelling studies have been conducted over north-western
Europe in summer conditions, showing that night-time dinitrogen
pentoxide (N<sub>2</sub>O<sub>5</sub>) heterogeneous reactive uptake is important
regionally in modulating particulate nitrate and has a~modest
influence on oxidative chemistry. Results from Weather Research and
Forecasting model with Chemistry (WRF-Chem) model
simulations, run with a detailed volatile organic compound (VOC)
gas-phase chemistry scheme and the Model for Simulating Aerosol
Interactions and Chemistry (MOSAIC) sectional aerosol scheme,
were compared with a series of airborne gas and particulate
measurements made over the UK in July 2010. Modelled mixing ratios of
key gas-phase species were reasonably accurate (correlations with
measurements of 0.7–0.9 for NO<sub>2</sub> and O<sub>3</sub>). However
modelled loadings of particulate species were less accurate
(correlation with measurements for particulate sulfate and ammonium
were between 0.0 and 0.6). Sulfate mass loadings were particularly low
(modelled means of 0.5–0.7 μg kg<sup>−1</sup><sub>air</sub>,
compared with measurements of
1.0–1.5 μg kg<sup>−1</sup><sub>air</sub>). Two flights from the
campaign were used as test cases – one with low relative humidity (RH)
(60–70%), the other with high RH (80–90%). N<sub>2</sub>O<sub>5</sub>
heterogeneous chemistry was found to not be important in the low-RH
test case; but in the high-RH test case it had a strong effect and
significantly improved the agreement between modelled and measured
NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub>. When the model failed to capture
atmospheric RH correctly, the modelled NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub>
mixing ratios for these flights differed significantly from the
measurements. This demonstrates that, for regional modelling which
involves heterogeneous processes, it is essential to capture the
ambient temperature and water vapour profiles.
<br><br>
The night-time NO<sub>3</sub> oxidation of VOCs across the whole region
was found to be 100–300 times slower than the daytime OH
oxidation of these compounds. The difference in contribution was less
for alkenes (× 80) and comparable for dimethylsulfide (DMS). However the
suppression of NO<sub>3</sub> mixing ratios across the domain by
N<sub>2</sub>O<sub>5</sub> heterogeneous chemistry has only a very slight,
negative, influence on this oxidative capacity. The influence on
regional particulate nitrate mass loadings is stronger. Night-time
N<sub>2</sub>O<sub>5</sub> heterogeneous chemistry maintains the production of
particulate nitrate within polluted regions: when this process is
taken into consideration, the daytime peak (for the 95th percentile)
of PM<sub>10</sub> nitrate mass loadings remains around
5.6 μg kg<sup>−1</sup><sub>air</sub>, but the night-time minimum
increases from 3.5 to 4.6 μg kg<sup>−1</sup><sub>air</sub>. The
sustaining of higher particulate mass loadings through the night by
this process improves model skill at matching measured aerosol nitrate
diurnal cycles and will negatively impact on regional air quality,
requiring this process to be included in regional models. |
| first_indexed | 2024-04-14T01:41:02Z |
| format | Article |
| id | doaj.art-0f2eb9bee9f54f1887f47e2918380fbb |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-14T01:41:02Z |
| publishDate | 2015-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-0f2eb9bee9f54f1887f47e2918380fbb2022-12-22T02:19:45ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242015-02-011531385140910.5194/acp-15-1385-2015WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western EuropeD. Lowe0S. Archer-Nicholls1W. Morgan2J. Allan3S. Utembe4B. Ouyang5E. Aruffo6M. Le Breton7R. A. Zaveri8P. Di Carlo9C. Percival10H. Coe11R. Jones12G. McFiggans13School of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth Sciences, University of Melbourne, Victoria 3010, AustraliaDepartment of Chemistry, University of Cambridge, Cambridge, UKCETEMPS – Dipartimento di Fisica, Universita di L'Aquila, L'Aquila, ItalySchool of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKAtmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland,Washington, USACETEMPS – Dipartimento di Fisica, Universita di L'Aquila, L'Aquila, ItalySchool of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKSchool of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKDepartment of Chemistry, University of Cambridge, Cambridge, UKSchool of Earth, Atmospheric & Environmental Sciences, University of Manchester, Manchester, UKChemical modelling studies have been conducted over north-western Europe in summer conditions, showing that night-time dinitrogen pentoxide (N<sub>2</sub>O<sub>5</sub>) heterogeneous reactive uptake is important regionally in modulating particulate nitrate and has a~modest influence on oxidative chemistry. Results from Weather Research and Forecasting model with Chemistry (WRF-Chem) model simulations, run with a detailed volatile organic compound (VOC) gas-phase chemistry scheme and the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) sectional aerosol scheme, were compared with a series of airborne gas and particulate measurements made over the UK in July 2010. Modelled mixing ratios of key gas-phase species were reasonably accurate (correlations with measurements of 0.7–0.9 for NO<sub>2</sub> and O<sub>3</sub>). However modelled loadings of particulate species were less accurate (correlation with measurements for particulate sulfate and ammonium were between 0.0 and 0.6). Sulfate mass loadings were particularly low (modelled means of 0.5–0.7 μg kg<sup>−1</sup><sub>air</sub>, compared with measurements of 1.0–1.5 μg kg<sup>−1</sup><sub>air</sub>). Two flights from the campaign were used as test cases – one with low relative humidity (RH) (60–70%), the other with high RH (80–90%). N<sub>2</sub>O<sub>5</sub> heterogeneous chemistry was found to not be important in the low-RH test case; but in the high-RH test case it had a strong effect and significantly improved the agreement between modelled and measured NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub>. When the model failed to capture atmospheric RH correctly, the modelled NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> mixing ratios for these flights differed significantly from the measurements. This demonstrates that, for regional modelling which involves heterogeneous processes, it is essential to capture the ambient temperature and water vapour profiles. <br><br> The night-time NO<sub>3</sub> oxidation of VOCs across the whole region was found to be 100–300 times slower than the daytime OH oxidation of these compounds. The difference in contribution was less for alkenes (× 80) and comparable for dimethylsulfide (DMS). However the suppression of NO<sub>3</sub> mixing ratios across the domain by N<sub>2</sub>O<sub>5</sub> heterogeneous chemistry has only a very slight, negative, influence on this oxidative capacity. The influence on regional particulate nitrate mass loadings is stronger. Night-time N<sub>2</sub>O<sub>5</sub> heterogeneous chemistry maintains the production of particulate nitrate within polluted regions: when this process is taken into consideration, the daytime peak (for the 95th percentile) of PM<sub>10</sub> nitrate mass loadings remains around 5.6 μg kg<sup>−1</sup><sub>air</sub>, but the night-time minimum increases from 3.5 to 4.6 μg kg<sup>−1</sup><sub>air</sub>. The sustaining of higher particulate mass loadings through the night by this process improves model skill at matching measured aerosol nitrate diurnal cycles and will negatively impact on regional air quality, requiring this process to be included in regional models.http://www.atmos-chem-phys.net/15/1385/2015/acp-15-1385-2015.pdf |
| spellingShingle | D. Lowe S. Archer-Nicholls W. Morgan J. Allan S. Utembe B. Ouyang E. Aruffo M. Le Breton R. A. Zaveri P. Di Carlo C. Percival H. Coe R. Jones G. McFiggans WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe Atmospheric Chemistry and Physics |
| title | WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe |
| title_full | WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe |
| title_fullStr | WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe |
| title_full_unstemmed | WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe |
| title_short | WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe |
| title_sort | wrf chem model predictions of the regional impacts of n sub 2 sub o sub 5 sub heterogeneous processes on night time chemistry over north western europe |
| url | http://www.atmos-chem-phys.net/15/1385/2015/acp-15-1385-2015.pdf |
| work_keys_str_mv | AT dlowe wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT sarchernicholls wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT wmorgan wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT jallan wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT sutembe wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT bouyang wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT earuffo wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT mlebreton wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT razaveri wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT pdicarlo wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT cpercival wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT hcoe wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT rjones wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope AT gmcfiggans wrfchemmodelpredictionsoftheregionalimpactsofnsub2subosub5subheterogeneousprocessesonnighttimechemistryovernorthwesterneurope |