Significant increase of summertime ozone at Mt. Tai in Central Eastern China: 2003–2015

Abstract. Tropospheric ozone (O3) is a trace gas playing key roles in atmospheric chemistry, air quality and climate change. In contrast to North America and Europe, China has limited long-term records of surface O3 that can be used to establish trends. In this study, we compiled the available observations of O3 at Mt. Tai – the highest mountain over the North China Plain (NCP), and analyzed their seasonal and diurnal behavior as well as the trends over 2003–2015. The summertime climatological air mass transport pattern was established by back trajectory calculation and a subsequent cluster analysis. A significant increase of surface O3 (p < 0.01) in the summertime from 2003 to 2015 was derived from a linear regression analysis, with increasing rates of 1.7 ppbv yr−1 for June and 2.1 ppbv yr−1 for the July–August period. Analysis of satellite trace gas retrievals indicates that the O3 increase was mainly due to the increased emissions of O3 precursors, in particular volatile organic compounds (VOCs). An important finding is that the emissions of nitrogen oxides (NOx) have diminished since 2011, but the increase of VOCs appears to have enhanced the ozone production efficiency and contributed to the observed O3 increase in northern China. This study provides direct evidence that controlling NOx alone, in the absence of VOC controls, is not sufficient to reduce regional O3 levels in North China. In addition, the ozone observations at this regionally representative mountain site are ideal for evaluating global and regional scale chemical transport models.

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Significant increase of summertime ozone at Mount Tai in Central Eastern China

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-10637-2016 ◽

2016 ◽

Vol 16 (16) ◽

pp. 10637-10650 ◽

Cited By ~ 93

Author(s):

Lei Sun ◽

Likun Xue ◽

Tao Wang ◽

Jian Gao ◽

Aijun Ding ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Production Efficiency ◽

North China ◽

Climate Model ◽

Eastern China ◽

Linear Regression Analysis ◽

Ozone Production ◽

The North ◽

Short Period ◽

Central Eastern

Abstract. Tropospheric ozone (O3) is a trace gas playing important roles in atmospheric chemistry, air quality and climate change. In contrast to North America and Europe, long-term measurements of surface O3 are very limited in China. We compile available O3 observations at Mt. Tai – the highest mountain over the North China Plain – during 2003–2015 and analyze the decadal change of O3 and its sources. A linear regression analysis shows that summertime O3 measured at Mt. Tai has increased significantly by 1.7 ppbv yr−1 for June and 2.1 ppbv yr−1 for the July–August average. The observed increase is supported by a global chemistry-climate model hindcast (GFDL-AM3) with O3 precursor emissions varying from year to year over 1980–2014. Analysis of satellite data indicates that the O3 increase was mainly due to the increased emissions of O3 precursors, in particular volatile organic compounds (VOCs). An important finding is that the emissions of nitrogen oxides (NOx) have diminished since 2011, but the increase of VOCs appears to have enhanced the ozone production efficiency and contributed to the observed O3 increase in central eastern China. We present evidence that controlling NOx alone, in the absence of VOC controls, is not sufficient to reduce regional O3 levels in North China in a short period.

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Analysis of a Regional Scale Chemical-Transport Model to Investigate the Potential Capability of Satellites for Identifying a Widespread Air Pollution Event

10.20944/preprints201708.0020.v1 ◽

2017 ◽

Author(s):

Jason Welsh ◽

Jack Fishman

Keyword(s):

Transport Model ◽

Regional Scale ◽

Ozone Production ◽

Metropolitan Region ◽

Trace Gas ◽

Chemical Transport Model ◽

Satellite Measurements ◽

Pollution Event ◽

Surface O3 ◽

Good Agreement

We use a regional scale photochemical transport model to investigate the surface concentrations and column integrated amounts of ozone (O3) and nitrogen dioxide (NO2) during a pollution event that occurred in the St. Louis metropolitan region in 2012. These trace gases will be two of the primary constituents that will be measured by TEMPO, an instrument on a geostationary platform, which will result in a dataset that has hourly temporal resolution during the daytime and ~4 km spatial resolution. Although air quality managers are most concerned with surface concentrations, satellite measurements provide a quantity that reflects a column amount, which may or may not be directly relatable to what is measured at the surface. The model results provide good agreement with observed surface O3 concentrations, which is the only trace gas dataset that can be used for verification. The model shows that a plume of O3 extends downwind from St. Louis and contains an integrated amount of ozone of ~ 16 DU (1 DU = 2.69 x 1016 mol. cm-2), a quantity that is two to three times lower than what was observed by satellite measurements during two massive pollution episodes in the 1980s. Based on the smaller isolatable emissions coming from St. Louis, this quantity is not unreasonable, but may also reflect the reduction of photochemical ozone production due to the implementation of emission controls that have gone into effect in the past few decades.

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Analysis of a Regional Scale Chemical-Transport Model to Investigate the Potential Capability of Satellites for Identifying a Widespread Air Pollution Event

10.20944/preprints201708.0020.v2 ◽

2017 ◽

Author(s):

Jason Welsh ◽

Jack Fishman

Keyword(s):

Transport Model ◽

Regional Scale ◽

Ozone Production ◽

Metropolitan Region ◽

Trace Gas ◽

Chemical Transport Model ◽

Satellite Measurements ◽

Pollution Event ◽

Surface O3 ◽

Good Agreement

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Dynamics and composition of the Asian summer monsoon anticyclone

10.5194/acp-2017-420 ◽

2017 ◽

Cited By ~ 1

Author(s):

Klaus-Dirk Gottschaldt ◽

Hans Schlager ◽

Robert Baumann ◽

Duy S. Cai ◽

Veronika Eyring ◽

...

Keyword(s):

Summer Monsoon ◽

Atmospheric Chemistry ◽

Asian Summer Monsoon ◽

Monsoon Season ◽

Lower Troposphere ◽

Equatorial Region ◽

Ozone Production ◽

Trace Gas ◽

Asian Summer ◽

Southern Fringe

Abstract. This study places HALO research aircraft observations in the upper-tropospheric Asian summer monsoon anticyclone (ASMA) obtained during the Earth System Model Validation (ESMVal) campaign in September 2012 into the context of regional, intra-annual variability by hindcasts with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations demonstrate that tropospheric trace gas profiles in the monsoon season are distinct from the rest of the year. Air uplifted from the lower troposphere to the tropopause layer dominates the eastern part of the ASMA’s interior, while the western part is characterised by subsidence down to the mid-troposphere. Soluble compounds are being washed out when uplifted by convection in the eastern part, where lightning simultaneously replenishes reactive nitrogen in the upper troposphere. Net photochemical ozone production is significantly enhanced in the ASMA, contrasted by an ozone depleting regime in the mid-troposphere and more neutral conditions in autumn and winter. An analysis of multiple monsoon seasons in the simulation shows that stratospherically influenced tropopause layer air is regularly entrained at the eastern ASMA flank, and then transported in the southern fringe around the interior region. Observed and simulated tracer-tracer relations reflect photochemical O3 production, as well as in-mixing from the lower troposphere and the tropopause layer. The simulation additionally shows entrainment of clean air from the equatorial region by northerly winds at the western ASMA flank. Although the in situ measurements were performed towards the end of summer, the main ingredients needed for their interpretation are present throughout the monsoon season. A transition between two dynamical modes of the ASMA took place during the HALO ESMVal campaign. Transport barriers of the original anticyclone are overcome effectively when it splits up. Air from the fringe is stirred into the interiors of the new anticyclones and vice versa. Instabilities of this and other types occur quite frequently. Our study emphasises their paramountcy for the trace gas composition of the ASMA and its outflow into regions around the world.

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A comparison of atmospheric composition using the Carbon Bond and Regional Atmospheric Chemistry Mechanisms

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-6923-2013 ◽

2013 ◽

Vol 13 (3) ◽

pp. 6923-6969 ◽

Cited By ~ 2

Author(s):

G. Sarwar ◽

J. Godowitch ◽

B. Henderson ◽

K. Fahey ◽

G. Pouliot ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Atmospheric Chemistry ◽

Production Efficiency ◽

Fine Particles ◽

Secondary Organic Aerosols ◽

Organic Aerosols ◽

Ozone Production ◽

Atmospheric Composition ◽

Organic Nitrate ◽

Carbon Bond

Abstract. We incorporate the recently developed Regional Atmospheric Chemistry Mechanism (version 2, RACM2) into the Community Multiscale Air Quality modeling system for comparison with the existing 2005 Carbon Bond mechanism with updated toluene chemistry (CB05TU). Compared to CB05TU, RACM2 enhances the domain-wide monthly mean hydroxyl radical concentrations by 46% and nitric acid by 26%. However, it reduces hydrogen peroxide by 2%, peroxyacetic acid by 94%, methyl hydrogen peroxide by 19%, peroxyacetyl nitrate by 40%, and organic nitrate by 41%. RACM2 predictions generally agree better with the observed data than the CB05TU predictions. RACM2 enhances ozone for all ambient levels leading to higher bias at low (< 60 ppbv) concentrations but improved performance at high (>70 ppbv) concentrations. The RACM2 ozone predictions are also supported by increased ozone production efficiency that agrees better with observations. Compared to CB05TU, RACM2 enhances the domain-wide monthly mean sulfate by 10%, nitrate by 6%, ammonium by 10%, anthropogenic secondary organic aerosols by 42%, biogenic secondary organic aerosols by 5%, and in-cloud secondary organic aerosols by 7%. Increased inorganic and organic aerosols with RACM2 agree better with observed data. While RACM2 enhances ozone and secondary aerosols by relatively large margins, control strategies developed for ozone or fine particles using the two mechanisms do not differ appreciably.

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Analysis of a Regional Scale Chemical-Transport Model to Investigate the Potential Capability of Satellites for Identifying a Widespread Air Pollution Event

10.20944/preprints201708.0020.v3 ◽

2017 ◽

Author(s):

Jason Welsh ◽

Jack Fishman

Keyword(s):

Transport Model ◽

Regional Scale ◽

Correlation Coefficients ◽

Ozone Production ◽

Metropolitan Region ◽

Trace Gas ◽

Chemical Transport Model ◽

Satellite Measurements ◽

Pollution Event ◽

Good Agreement

We use a regional scale photochemical transport model to investigate the surface concentrations and column integrated amounts of ozone (O3) and nitrogen dioxide (NO2) during a pollution event that occurred in the St. Louis metropolitan region in 2012. These trace gases will be two of the primary constituents that will be measured by TEMPO (Tropospheric Emissions: Monitoring of Pollution), an instrument on a geostationary platform, which will result in a dataset that has hourly temporal resolution during the daytime and ~4 km spatial resolution. Although air quality managers are most concerned with surface concentrations, satellite measurements provide a quantity that reflects a column amount, which may or may not be directly relatable to what is measured at the surface. Our model results provide reasonably good agreement with observed surface O3 concentrations (correlation coefficients ranging from 0.69 to 0.87 at each of the nine monitoring stations in the St. Louis region), which is the only trace gas dataset that can be used for verification. The model shows that a plume of O3 extends downwind from St. Louis and contains an integrated amount of ozone of ~ 16 Dobson Units (DU; 1 DU = 2.69 x 1016 molecules cm-2), an amount lower than what was observed during two massive pollution episodes in the 1980s. Based on the smaller isolatable emissions coming from St. Louis, this quantity is not unreasonable, but may also reflect the reduction of photochemical ozone production due to the implementation of emission controls that have gone into effect since the 1980s.

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Extreme droughts/floods and their impacts on harvest derived from historical documents in Eastern China during 801–1910

10.5194/cp-2019-14 ◽

2019 ◽

Author(s):

Zhixin Hao ◽

Maowei Wu ◽

Jingyun Zheng ◽

Jiewei Chen ◽

Xuezhen Zhang ◽

...

Keyword(s):

North China ◽

Eastern China ◽

Regional Scale ◽

Extreme Drought ◽

Historical Documents ◽

Warm Climate ◽

Extreme Flood ◽

Historical Times ◽

The Impact

Abstract. Chinese historical documents recorded plenty of information related with climate change and grain harvest, which are helpful to explore the impacts of extreme drought/flood on crops and the implications on adaptation for agriculture to more extreme climate probability in the context of global warming. Here, we used the reconstructed extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents to investigate the connection between the occurrences of extreme drought/flood in eastern China and poor harvest during 801–1910. The results showed that more extreme droughts occurred in 801–870, 1031–1230, 1481–1530 and 1581–1650 over whole eastern China. On regional scale, more extreme droughts occurred in 1031–1100, 1441–1490, 1601–1650 and 1831–1880 in North China, 801–870, 1031–1120, 1161–1220 and 1471–1530 in Jianghuai, 991–1040, 1091–1150, 1171–1230, 1411–1470 and 1481–1530 in Jiangnan. The grain harvest was poor in periods of 801–940, 1251–1650 and 1841 to 1910, but bumper in periods of 951–1250 and 1651–1840 approximately. For entire period of 801–1910, more occurrence of extreme drought in any sub–region of eastern China could significantly reduce harvest in the long term average, but the connection between harvest and extreme flood seemed to be much weaker. The co–occurrence of extreme drought and extreme flood in different sub–regions in the same year had a greater impact on harvest yield. However, the connection between the occurrence of poor harvest and regional extreme drought was weak in the warm epoch of 920–1300 but strong in the cold epoch of 1310–1880, which implicated warm climate might weaken the impact of extreme drought on poor harvest during historical times.

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Near-ground ozone source attributions and outflow in central eastern China during MTX2006

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-7335-2008 ◽

2008 ◽

Vol 8 (24) ◽

pp. 7335-7351 ◽

Cited By ~ 73

Author(s):

J. Li ◽

Z. Wang ◽

H. Akimoto ◽

K. Yamaji ◽

M. Takigawa ◽

...

Keyword(s):

Transport Model ◽

Eastern China ◽

Regional Scale ◽

Horizontal Distribution ◽

Photochemical Reactions ◽

Ozone Production ◽

Chemical Transport Model ◽

Ozone Level ◽

Study Region ◽

Central Eastern

Abstract. A 3-D regional chemical transport model, the Nested Air Quality Prediction Model System (NAQPMS), with an on-line tracer tagging module was used to study the source of the near-ground (<1.5 km above ground level) ozone at Mt. Tai (36.25° N, 117.10° E, 1534 m a.s.l.) in Central Eastern China (CEC) during the Mount Tai eXperiment 2006 (MTX2006). The model reproduced the temporal and spatial variations of near-ground ozone and other pollutants, and it captured highly polluted and clean cases well. The simulated near-ground ozone level over CEC was 60–85 ppbv (parts per billion by volume), which was higher than values in Japan and over the North Pacific (20–50 ppbv). The simulated tagged tracer data indicated that the regional-scale transport of chemically produced ozone over other areas in CEC contributed to the greatest fraction (49%) of the near-ground mean ozone at Mt. Tai in June; in situ photochemistry contributed only 12%. Due to high anthropogenic and biomass burning emissions that occurred in the southern part of the CEC, the contribution to ground ozone levels from this area played the most important role (32.4 ppbv, 37.9% of total ozone) in the monthly mean ozone concentration at Mt. Tai; values reached 59 ppbv (62%) on 6–7 June 2006. The monthly mean horizontal distribution of chemically produced ozone from various ozone production regions indicated that photochemical reactions controlled the spatial distribution of O3 over CEC. The regional-scale transport of pollutants also played an important role in the spatial and temporal distribution of ozone over CEC. Chemically produced ozone from the southern part of the study region can be transported northeastwardly to the northern rim of CEC; the mean contribution was 5–10 ppbv, and it reached 25 ppbv during high ozone events. Studies of the outflow of CEC ozone and its precursors, as well as their influences and contributions to the ozone level over adjacent regions/countries, revealed that the contribution of CEC ozone to mean ozone mixing ratios over the Korean Peninsula and Japan was 5–15 ppbv, of which about half was due to the direct transport of ozone from CEC and half was produced locally by ozone precursors transported from CEC.

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Gaseous pollutants in Beijing urban area during the heating period 2007–2008: variability, sources, meteorological, and chemical impacts

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-8157-2011 ◽

2011 ◽

Vol 11 (15) ◽

pp. 8157-8170 ◽

Cited By ~ 85

Author(s):

W. Lin ◽

X. Xu ◽

B. Ge ◽

X. Liu

Keyword(s):

Production Efficiency ◽

Linear Regression Analysis ◽

Multiple Linear Regression Analysis ◽

Point Sources ◽

Ozone Production ◽

Urban Site ◽

Gaseous Pollutants ◽

Winter Period ◽

Heating Period ◽

Frequency Distributions

Abstract. Gaseous pollutants, NOy/NOx, SO2, CO, and O3, were measured at an urban site in Beijing from 17 November 2007 to 15 March 2008. The average concentrations (with ± 1σ) of NO, NO2, NOx, NOy, CO, SO2, and O3 were 29.0 ± 2.7 ppb, 33.7 ± 1.4 ppb, 62.7 ± 4.0 ppb, 72.8 ± 4.5 ppb, 1.99 ± 0.13 ppm, 31.9 ± 2.0 ppb, and 11.9 ± 0.8 ppb, respectively, with hourly maxima of 200.7 ppb, 113.5 ppb, 303.9 ppb, 323.2 ppb, 15.06 ppm, 147.3 ppb, and 69.7 ppb, respectively. The concentrations of the pollutants show "saw-toothed" patterns, which are attributable mainly to changes in wind direction and speed. The frequency distributions of the hourly mean concentrations of NOy, SO2, CO, and O3 can all be decomposed in the two Lorentz curves, with their peak concentrations representing background levels under different conditions. During the observation period, the average ratio NOx/NOy was 0.86 ± 0.10, suggesting that the gaseous pollutants in Beijing in winter are mainly from local emissions. Data of O3, NOz, and NOx/NOy indicate that photochemistry can take place in Beijing even in the cold winter period. Based on the measurements of O3, NOx, and NOy, ozone production efficiency (OPE) is estimated to be in the range of 0–8.9 (ppb ppb−1) with the mean(± 1σ) and median values being 1.1(± 1.6) and 0.5 (ppb ppb−1), respectively, for the winter 2007–2008 in Beijing. This low OPE would cause a photochemical O3 source of 5 ppb day−1, which is small but significant for surface O3 in winter in Beijing. Downward transport of O3-rich air from the free troposphere is the more important factor for the enhancement of the O3 level in the surface layer, while high NO level for the destruction of O3. The concentrations of SO2, CO, and NOx are strongly correlated among each other, indicating that they are emitted by some common sources. Multiple linear regression analysis is applied to the concentrations of NOy, SO2, and CO and empirical equations are obtained for the NOy concentration. Based the equations, the relative contributions from mobile and point sources to NOy is estimated to be 66 ± 30 % and 40 ± 16 %, respectively, suggesting that even in the heating period, mobile sources in Beijing contribute more to NOy than point sources.

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The impact of resolution on ship plume simulations with NO<sub>x</sub> chemistry

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-7505-2009 ◽

2009 ◽

Vol 9 (19) ◽

pp. 7505-7518 ◽

Cited By ~ 21

Author(s):

C. L. Charlton-Perez ◽

M. J. Evans ◽

J. H. Marsham ◽

J. G. Esler

Keyword(s):

Atmospheric Chemistry ◽

Production Efficiency ◽

Marine Boundary Layer ◽

Transport Model ◽

Climate Impact ◽

Ozone Production ◽

Finite Model ◽

Chemical Transport Model ◽

Realistic Representation ◽

The Impact

Abstract. A high resolution chemical transport model of the marine boundary layer is designed in order to investigate the detailed chemical evolution of a ship plume in a tropical location. To estimate systematic errors due to finite model resolution, otherwise identical simulations are run at a range of model resolutions. Notably, to obtain comparable plumes in the different simulations, it is found necessary to use an advection scheme consistent with the Large Eddy Model representation of sub-grid winds for those simulations with degraded resolution. Our simulations show that OH concentration, NOx lifetime and ozone production efficiency of the model change by 8%, 32% and 31% respectively between the highest (200 m×200 m×40 m) and lowest resolution (9600 m×9600 m×1920 m) simulations. Interpolating to the resolution of a typical global composition transport model (CTM, 5°×5°), suggests that a CTM overestimates OH, NOx lifetime and ozone production efficiency by approximately 15%, 55% and 59% respectively. For the first time, by explicitly degrading the model spatial resolution we show that there is a significant reduction in model skill in accurately simulating the aforementioned quantities due to the coarse resolution of these CTMs and the non-linear nature of atmospheric chemistry. These results are significant for the assessment and forecasting of the climate impact of ship NOx and indicate that for realistic representation of ship plume emissions in CTMs, some suitable parametrisation is necessary at current global model resolutions.

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