scholarly journals Springtime photochemical ozone production observed in the upper troposphere over east Asia

2002 ◽  
Vol 108 (D3) ◽  
Author(s):  
Y. Miyazaki ◽  
K. Kita ◽  
Y. Kondo ◽  
M. Koike ◽  
M. Ko ◽  
...  
Keyword(s):  
East Asia ◽  
Ozone Production ◽  
Upper Troposphere ◽  
Photochemical Ozone

Unexpected Fast Monoterpene Oxidation In Eastern China

2021 ◽  
Author(s):  
Haichao Wang
Keyword(s):  
Eastern China ◽  
Field Measurements ◽  
Ozone Production ◽  
Nitrate Radical ◽  
Peroxy Radicals ◽  
Ozone Pollution ◽  
Volatile Organic ◽  
Secondary Aerosols ◽  
Photochemical Ozone

<p>Monoterpene plays an important role in the formation of secondary aerosols and ozone in the troposphere. However, the field characterization of monoterpene chemistry in ozone pollution is still very sparse. Here we report fast daytime oxidation of monoterpene by hydroxyl radical, nitrate radical and ozone based on field measurements in Eastern China. We find fast monoterpene oxidation produces peroxy radicals efficiently and enhances the photochemical ozone production largely with an additional 8.6 ppb of ozone production per day on average (14%), whose effect was even more important than that of isoprene chemistry in the analyzed dataset. We propose that the reduction of anthropogenic volatile organic compounds should be much more stringent in the presence of high monoterpenes to alleviating ozone pollution.</p>

scholarly journals Characterising the seasonal and geographical variability in tropospheric ozone, stratospheric influence and recent changes

2019 ◽  
Vol 19 (6) ◽  
pp. 3589-3620 ◽  
Author(s):  
Ryan S. Williams ◽  
Michaela I. Hegglin ◽  
Brian J. Kerridge ◽  
Patrick Jöckel ◽  
Barry G. Latter ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Lower Stratosphere ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Data Availability ◽  
Ozone Production ◽  
Upper Troposphere ◽  
The World

Abstract. The stratospheric contribution to tropospheric ozone (O3) has been a subject of much debate in recent decades but is known to have an important influence. Recent improvements in diagnostic and modelling tools provide new evidence that the stratosphere has a much larger influence than previously thought. This study aims to characterise the seasonal and geographical distribution of tropospheric ozone, its variability, and its changes and provide quantification of the stratospheric influence on these measures. To this end, we evaluate hindcast specified-dynamics chemistry–climate model (CCM) simulations from the European Centre for Medium-Range Weather Forecasts – Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model and the Canadian Middle Atmosphere Model (CMAM), as contributed to the International Global Atmospheric Chemistry – Stratosphere-troposphere Processes And their Role in Climate (IGAC-SPARC) (IGAC–SPARC) Chemistry Climate Model Initiative (CCMI) activity, together with satellite observations from the Ozone Monitoring Instrument (OMI) and ozone-sonde profile measurements from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) over a period of concurrent data availability (2005–2010). An overall positive, seasonally dependent bias in 1000–450 hPa (∼0–5.5 km) sub-column ozone is found for EMAC, ranging from 2 to 8 Dobson units (DU), whereas CMAM is found to be in closer agreement with the observations, although with substantial seasonal and regional variation in the sign and magnitude of the bias (∼±4 DU). Although the application of OMI averaging kernels (AKs) improves agreement with model estimates from both EMAC and CMAM as expected, comparisons with ozone-sondes indicate a positive ozone bias in the lower stratosphere in CMAM, together with a negative bias in the troposphere resulting from a likely underestimation of photochemical ozone production. This has ramifications for diagnosing the level of model–measurement agreement. Model variability is found to be more similar in magnitude to that implied from ozone-sondes in comparison with OMI, which has significantly larger variability. Noting the overall consistency of the CCMs, the influence of the model chemistry schemes and internal dynamics is discussed in relation to the inter-model differences found. In particular, it is inferred that CMAM simulates a faster and shallower Brewer–Dobson circulation (BDC) compared to both EMAC and observational estimates, which has implications for the distribution and magnitude of the downward flux of stratospheric ozone over the most recent climatological period (1980–2010). Nonetheless, it is shown that the stratospheric influence on tropospheric ozone is significant and is estimated to exceed 50 % in the wintertime extratropics, even in the lower troposphere. Finally, long-term changes in the CCM ozone tracers are calculated for different seasons. An overall statistically significant increase in tropospheric ozone is found across much of the world but particularly in the Northern Hemisphere and in the middle to upper troposphere, where the increase is on the order of 4–6 ppbv (5 %–10 %) between 1980–1989 and 2001–2010. Our model study implies that attribution from stratosphere–troposphere exchange (STE) to such ozone changes ranges from 25 % to 30 % at the surface to as much as 50 %–80 % in the upper troposphere–lower stratosphere (UTLS) across some regions of the world, including western Eurasia, eastern North America, the South Pacific and the southern Indian Ocean. These findings highlight the importance of a well-resolved stratosphere in simulations of tropospheric ozone and its implications for the radiative forcing, air quality and oxidation capacity of the troposphere.

scholarly journals Diagnosis of Photochemical Ozone Production Rates and Limiting Factors in Continental Outflow Air Masses Reaching Fukue Island, Japan: Ozone-Control Implications

2016 ◽  
Vol 16 (2) ◽  
pp. 430-441 ◽  
Author(s):  
Yugo Kanaya ◽  
Hiroshi Tanimoto ◽  
Yoko Yokouchi ◽  
Fumikazu Taketani Fumikazu Taketani ◽  
Yuichi Komazaki ◽  
...  
Keyword(s):  
Ozone Production ◽  
Limiting Factors ◽  
Production Rates ◽  
Air Masses ◽  
Ozone Control ◽  
Photochemical Ozone ◽  
Continental Outflow

scholarly journals Dominant Modes of Tropospheric Ozone Variation over East Asia from GOME Observations

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yi Liu ◽  
Yuli Zhang ◽  
Yong Wang ◽  
Chuanxi Liu ◽  
Zhaonan Cai ◽  
...  
Keyword(s):  
East Asia ◽  
Tropospheric Ozone ◽  
Asian Summer Monsoon ◽  
Principal Component ◽  
Total Variance ◽  
Ozone Production ◽  
The Tibetan Plateau ◽  
Westerly Jet ◽  
Sign Distribution ◽  
Subtropical Westerly Jet

The variation in tropospheric ozone over East Asia was analyzed using tropospheric column ozone data measured by the Global Ozone Monitoring Experiment (GOME) satellite. An empirical orthogonal function (EOF) analysis was carried out to derive the dominant modes of the variation in the tropospheric ozone volume-mixing ratio (TOVMR). The EOF1 mode, which explained 61.5% of the total variance, showed a same-sign distribution over all of East Asia, with a belt of enhanced ozone concentrations around 40°N. The principal component of EOF1 (PC1) suggested that photochemical ozone production together with Brewer-Dobson circulation and subtropical westerly jet plays important roles in modulating the seasonal variation of the TOVMR; ozone-rich air produced by photochemical processes was transported from the stratosphere to the troposphere by BD circulation and this ozone-rich air was then blocked by the subtropical westerly jet and accumulated north of the jet. The EOF2 mode explained 29.2% of the total variance with an opposite-sign pattern on the north and south side of 35°N. When anticyclonic circulation transported ozone-poor air from the upwelling area over the Bay of Bengal towards the Tibetan Plateau during the onset of the Asian summer monsoon, tropospheric ozone in this region decreased dramatically.

Summertime surface ozone variation over East Asia in CCMI

2020 ◽  
Author(s):  
Jieun Wie ◽  
Hyo-Jin Park ◽  
Hyomee Lee ◽  
Byung-Kwon Moon
Keyword(s):  
East Asia ◽  
Climate Model ◽  
Southern Oscillation ◽  
Surface Ozone ◽  
Eastern China ◽  
Empirical Orthogonal Functions ◽  
Ozone Production ◽  
Shortwave Radiation ◽  
Horizontal Wind ◽  
Second Mode

<p>The concentration of surface ozone in East Asia is high due to strong solar radiation, but decreases in areas affected by summer monsoons. This study analyzes the summer surface ozone variations in East Asia using meteorological and atmospheric chemistry variables in 12 models participating in Chemistry-Climate Model Initiative (CCMI) for the period of 1979 to 2010. The concentration of 850 hPa ozone was identified two modes by Empirical Orthogonal Functions (EOF) analysis. The first mode is an increase in all regions over East Asia, mainly in eastern China. This mode was associated with downward wind, weak horizontal wind speed, increase in temperatures, decrease in precipitation. The second mode showed high ozone concentrations in eastern China and low in northern Japan. In eastern China, temperatures and precipitation are decreased, and shortwave radiation reaches the surface is increased. In addition, the concentration of nitrogen oxides and carbon monoxide and the net ozone production are increased. The second mode was highly correlated with El Nino-Southern Oscillation (ENSO) and western North Pacific subtropical high (WNPSH) indices and was found to be closely associated with East Asian summer monsoons.</p><p> </p><p>Acknowledgements: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2019R1A2C1008549). We acknowledge the modeling groups for making their simulations available for this analysis, the joint WCRP SPARC/IGAC Chemistry–Climate Model Initiative (CCMI) for organizing and coordinating the model simulations and data analysis activity, and the British Atmospheric Data Centre (BADC) for collecting and archiving the CCMI model output.</p>

scholarly journals Impact of model resolution on chemical ozone formation in Mexico City: application of the WRF-Chem model

2010 ◽  
Vol 10 (18) ◽  
pp. 8983-8995 ◽  
Author(s):  
X. Tie ◽  
G. Brasseur ◽  
Z. Ying
Keyword(s):  
Mexico City ◽  
Urban Areas ◽  
Air Pollutants ◽  
Emission Inventory ◽  
Meteorological Conditions ◽  
Transport Processes ◽  
Ozone Production ◽  
Model Resolution ◽  
Coarse Resolution ◽  
Photochemical Ozone

Abstract. The resolution of regional chemical/dynamical models has important effects on the calculation of the distributions of air pollutants in urban areas. In this study, the sensitivity of air pollutants and photochemical ozone production to different model resolutions is assessed by applying a regional chemical/dynamical model (version 3 of Weather Research and Forecasting Chemical model – WRF-Chemv3) to the case of Mexico City. The model results with 3, 6, 12, and 24 km resolutions are compared to local surface measurements of CO, NOx, and O3. The study shows that the model resolutions of 3 and 6 km provide reasonable simulations of surface CO, NOx, and O3 concentrations and of diurnal variations. The model tends to underestimate the measurements when the resolution is reduced to 12 km or less. The calculated surface CO, NOx, and O3 concentrations at 24 km resolution are significantly lower than measured values. This study suggests that the ratio of the city size to the threshold resolution is 6 to 1, and that this ratio can be considered as a test value in other urban areas for model resolution setting. There are three major factors related to the effects of model resolution on the calculations of O3 and O3 precursors, including; (1) the calculated meteorological conditions, (2) the spatial distribution for the emissions of ozone precursors, and (3) the non-linearity in the photochemical ozone production. Model studies suggest that, for the calculations of O3 and O3 precursors, spatial resolutions (resulting from different meteorological condition and transport processes) have larger impacts than the effect of the resolution associated with emission inventories. The model shows that, with coarse resolution of emission inventory (24 km) and high resolution for meteorological conditions (6 km), the calculated CO and O3 are considerably improved compared to the results obtained with coarse resolution for both emission inventory and meteorological conditions (24 km). The resolution of the surface emissions has important effects on the calculated concentration fields, but the effects are smaller than those resulting from the model resolution. This study also suggests that the effect of model resolution on O3 precursors leads to important impacts on the photochemical formation of ozone. This results directly from the non-linear relationship between O3 formation and O3 precursor concentrations. Finally, this study suggests that, considering the balance between model performance and required computation time on current computers, the 6 km resolution is an optimal resolution for the calculation of ozone and its precursors in urban areas like Mexico City.

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