Springtime daily variations in lower-tropospheric ozone over east Asia: the role of cyclonic activity and pollution as observed from space with IASI

Abstract. We use satellite observations from IASI (Infrared Atmospheric Sounding Interferometer) on board the MetOp-A satellite to evaluate the springtime daily variations in lower-tropospheric ozone over east Asia. The availability of semi-independent columns of ozone from the surface up to 12 km simultaneously with CO columns provides a powerful observational data set to diagnose the processes controlling tropospheric ozone enhancement on synoptic scales. By combining IASI observations with meteorological reanalyses from ERA-Interim, we develop an analysis method based only on IASI ozone and CO observations to identify the respective roles of the stratospheric source and the photochemical source in ozone distribution and variations over east Asia. The succession of low- and high-pressure systems drives the day-to-day variations in lower-tropospheric ozone. A case study analysis of one frontal system and one cut-off low system in May 2008 shows that reversible subsiding and ascending ozone transfers in the upper-troposphere–lower-stratosphere (UTLS) region, due to the tropopause perturbations occurring in the vicinity of low-pressure systems, impact free and lower-tropospheric ozone over large regions, especially north of 40° N, and largely explain the ozone enhancement observed with IASI for these latitudes. Irreversible stratosphere–troposphere exchanges of ozone-rich air masses occur more locally in the southern and southeastern flanks of the trough. The contribution to the lower-tropospheric ozone column is difficult to dissociate from the tropopause perturbations generated by weather systems. For regions south of 40° N, a significant correlation has been found between lower-tropospheric ozone and carbon monoxide (CO) observations from IASI, especially over the North China Plain (NCP). Considering carbon monoxide observations as a pollutant tracer, the O3–CO correlation indicates that the photochemical production of ozone from primary pollutants emitted over such large polluted regions significantly contributes to the ozone enhancements observed in the lower troposphere via IASI. When low-pressure systems circulate over the NCP, stratospheric and pollution sources play a concomitant role in the ozone enhancement. IASI's 3-D observational capability allows the areas in which each source dominates to be determined. Moreover, the studied cut-off low system has enough potential convective capacity to uplift pollutants (ozone and CO) and to transport them to Japan. The increase in the enhancement ratio of ozone to CO from 0.16 on 12 May over the North China Plain to 0.28 over the Sea of Japan on 14 May indicates photochemical processing during the plume transport.

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Quantifying impacts of crop residue burning in the North China Plain on summertime tropospheric ozone over East Asia

Atmospheric Environment ◽

10.1016/j.atmosenv.2018.09.018 ◽

2018 ◽

Vol 194 ◽

pp. 14-30 ◽

Cited By ~ 1

Author(s):

Mingliang Ma ◽

Kaixu Bai ◽

Fengxue Qiao ◽

Runhe Shi ◽

Wei Gao

Keyword(s):

East Asia ◽

Tropospheric Ozone ◽

Crop Residue ◽

North China Plain ◽

North China ◽

The North ◽

The North China Plain ◽

Crop Residue Burning

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The combined effect of two westerly jet waveguides on heavy haze in the North China Plain in November and December 2015

10.5194/acp-2019-826 ◽

2019 ◽

Author(s):

Xiadong An ◽

Lifang Sheng ◽

Qian Liu ◽

Chun Li ◽

Yang Gao ◽

...

Keyword(s):

East Asia ◽

Rossby Wave ◽

South China ◽

North China Plain ◽

North China ◽

Combined Effect ◽

The North ◽

Westerly Jet ◽

The North China Plain ◽

Subtropical Westerly Jet

Abstract. Severe haze occurred in the North China Plain (NCP) from November to December 2015, with a wide spatial range and long duration. In this paper, the combined effect of two westerly jet waveguides on haze in the NCP was investigated based on visibility observational data and NCEP/NCAR reanalysis data. The results showed that the two Rossby waveguides within the westerly jet originating from the Mediterranean were responsible for the haze formation in the NCP. The Rossby wave propagated eastward along the subtropical westerly jet and the polar front jet, causing an anomalous anticyclone over the Sea of Japan and anticyclonic wind speed shear at 850 hPa over the NCP, which enhanced the anomalous descending air motion in the middle and lower troposphere and subsequently resulted in a stable atmosphere. Furthermore, the Rossby wave weakened the East Asia trough and Ural ridge, and strengthened the anomalous southerly wind at 850 hPa over the coastal areas of east China, decelerating the East Asia winter monsoon. The above meteorological conditions modulated haze accumulation in November and December 2015. Meanwhile, continuous rainfall related to ascending motion due to Rossby wave propagation along the subtropical westerly jet occurred in a large area of southern China. The latent heat released by rainfall acted as a heat source, inducing convection over South China. This further strengthened the ascending motion over South China so that the descending motion over the NCP was maintained, favoring the maintenance of severe haze. This study is of great significance to elucidate the formation and maintenance mechanism of large-scale haze in the NCP in late fall and boreal winter.

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Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-2843-2015 ◽

2015 ◽

Vol 15 (5) ◽

pp. 2843-2866 ◽

Cited By ~ 21

Author(s):

K. Ding ◽

J. Liu ◽

A. Ding ◽

Q. Liu ◽

T. L. Zhao ◽

...

Keyword(s):

East Asia ◽

Forest Fires ◽

North China Plain ◽

North China ◽

Anthropogenic Sources ◽

Free Troposphere ◽

Transport Pathways ◽

Upper Troposphere ◽

The North ◽

The North China Plain

Abstract. East Asia has experienced rapid development with increasing carbon monoxide (CO) emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality around the world. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in the East China Sea and the Sea of Japan from 2003 to 2005 are examined with spaceborne Measurements of Pollution in the Troposphere (MOPITT) data, in combination with aircraft measurements from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. High CO abundances of 300–550 ppbv are observed in MOZAIC data in the free troposphere during these episodes. These are among the highest CO abundances documented at these altitudes. On average, such episodes with CO over 400 ppbv (in the 2003 and 2004 cases) and between 200 and 300 ppbv (in the 2005 case) may occur 2–5 and 10–20% in time, respectively, in the respective altitudes over the region. Correspondingly, elevated CO is shown in MOPITT daytime data in the middle to upper troposphere in the 2003 case, in the lower to middle troposphere in the 2004 case, and in the upper troposphere in the 2005 case. Through analyses of the simulations from a chemical transport model GEOS-Chem and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases. In the 2003 case, emissions from large forest fires near Lake Baikal dominated the elevated CO, which had been rapidly transported upward by a frontal system from the fire plumes. In the 2004 case, anthropogenic CO from the North China Plain experienced frontal lifting and mostly reached ~ 700 hPa near the East China Sea, while CO from biomass burning over Indochina experienced orographic lifting, lee-side-trough-induced convection, and frontal lifting through two separate transport pathways, leading to two distinct CO enhancements around 700 and 300 hPa. In the 2005 case, the observed CO of ~ 300 ppbv around 300 hPa originated from anthropogenic sources over the Sichuan Basin and the North China Plain and from forest fires over Indochina. The high CO was transported to such altitudes through strong frontal lifting, interacting with convection and orographic lifting. These cases show that topography affects vertical transport of CO in East Asia via different ways, including orographic uplifting over the Hengduan Mountains, assisting frontal lifting in the North China Plain, and facilitating convection in the Sichuan Basin. In particular, topography-induced lee-side troughs over Indochina led to strong convection that assisted CO uplifting to the upper troposphere. This study shows that the new daytime MOPITT near-infrared (NIR) and thermal-infrared (TIR) data (version 5 or above) have enhanced vertical sensitivity in the free troposphere and may help qualitative diagnosis of vertical transport processes in East Asia.

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Lower tropospheric ozone over the North China Plain: variability and trends revealed by IASI satellite observations for 2008–2016

10.5194/acp-2018-413 ◽

2018 ◽

Author(s):

Gaëlle Dufour ◽

Maxim Eremenko ◽

Matthias Beekmann ◽

Juan Cuesta ◽

Gilles Foret ◽

...

Keyword(s):

Tropospheric Ozone ◽

North China Plain ◽

North China ◽

Satellite Observations ◽

Emissions Reduction ◽

Nox Emissions ◽

So2 Emissions ◽

Emission Reductions ◽

The North ◽

The North China Plain

Abstract. China, and especially the North China Plain (NCP), is a highly polluted region. Emission reductions have been applied since about 10 years, starting with SO2 emissions in 2006 and with NOx emissions in 2010. Recent studies show a decrease of NO2 tropospheric column since 2013 and attributed to the NOx emissions reduction. Quantifying how these emission reductions translates to the ozone concentrations remains. In this study, we use the lower tropospheric (LT) columns (surface-6 km asl) derived from the IASI satellite instrument to describe the variability and trend of LT ozone over the NCP for 2008–2016. Deseasonalized monthly timeseries show two distinct periods: a first period (2008–2012) with no significant trend (

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Springtime variability of lower tropospheric ozone over Eastern Asia: contributions of cyclonic activity and pollution as observed from space with IASI

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-9203-2015 ◽

2015 ◽

Vol 15 (6) ◽

pp. 9203-9252

Author(s):

G. Dufour ◽

M. Eremenko ◽

J. Cuesta ◽

C. Doche ◽

G. Foret ◽

...

Keyword(s):

Carbon Monoxide ◽

East Asia ◽

Tropospheric Ozone ◽

Lower Troposphere ◽

Temporal Distribution ◽

Low Pressure ◽

Eastern Asia ◽

Air Masses ◽

North East ◽

Low Pressure Systems

Abstract. We use satellite observations from IASI (Infrared Atmospheric Sounding Interferometer) on board the MetOp-A satellite to evaluate the springtime daily variability of lower tropospheric ozone at the scale of Eastern Asia. Lower tropospheric partial columns from surface to 6 km are retrieved from IASI with a maximum of sensitivity between 3 and 4 km. We focus our analysis on the month of May 2008 for which tropospheric ozone presents typically amongst the largest concentrations along the year. We combine IASI observations with meteorological reanalyses from ERA-Interim in order to investigate the processes that control the spatial and temporal distribution of lower tropospheric ozone, especially in case of ozone enhancement. The succession of low- and high-pressure systems drives the day-to-day variability of lower tropospheric ozone over North East Asia. The analysis of two episodes with ozone enhancement at the synoptic scale of East Asia shows that the reversible subsiding and ascending ozone transfers in the UTLS region occurring in the vicinity of low-pressure systems and related to tropopause height affect the upper and lower tropospheric ozone over large regions, especially north to 40° N and largely explain the ozone enhancement observed with IASI for these latitudes. Irreversible downward transport of ozone-rich air masses from the UTLS to the lower troposphere occurs more locally. Its contribution to the lower tropospheric ozone column is difficult to dissociate from the tropopause perturbations induced by the weather systems. For regions south to 40° N, a significant correlation between lower tropospheric ozone and carbon monoxide (CO) observations from IASI has been found, especially over North China Plain (NCP). Considering carbon monoxide observations as pollutant tracer, the O3-CO correlation indicates that the photochemical production of ozone from primary pollutants emitted over such large polluted regions significantly contributes to the ozone enhancements observed with IASI in the lower troposphere. When low-pressure systems circulate over NCP, stratospheric and pollution sources play a concomitant role in the ozone enhancements. Moreover, in that case, evidence of pollutant export from NCP towards the east is shown. Finally, we show that semi-independent columns of ozone from the surface up to 12 km associated with CO columns from IASI constitute a powerful observational dataset to investigate the processes controlling tropospheric enhancement of ozone at synoptic scales.

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Correcting model biases of CO in East Asia: impact on oxidant distributions during KORUS-AQ

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-14617-2020 ◽

2020 ◽

Vol 20 (23) ◽

pp. 14617-14647

Author(s):

Benjamin Gaubert ◽

Louisa K. Emmons ◽

Kevin Raeder ◽

Simone Tilmes ◽

Kazuyuki Miyazaki ◽

...

Keyword(s):

East Asia ◽

North China Plain ◽

North China ◽

Climate Models ◽

Liaoning Province ◽

Late Winter ◽

Model Errors ◽

The North ◽

Chemistry Research ◽

The North China Plain

Abstract. Global coupled chemistry–climate models underestimate carbon monoxide (CO) in the Northern Hemisphere, exhibiting a pervasive negative bias against measurements peaking in late winter and early spring. While this bias has been commonly attributed to underestimation of direct anthropogenic and biomass burning emissions, chemical production and loss via OH reaction from emissions of anthropogenic and biogenic volatile organic compounds (VOCs) play an important role. Here we investigate the reasons for this underestimation using aircraft measurements taken in May and June 2016 from the Korea–United States Air Quality (KORUS-AQ) experiment in South Korea and the Air Chemistry Research in Asia (ARIAs) in the North China Plain (NCP). For reference, multispectral CO retrievals (V8J) from the Measurements of Pollution in the Troposphere (MOPITT) are jointly assimilated with meteorological observations using an ensemble adjustment Kalman filter (EAKF) within the global Community Atmosphere Model with Chemistry (CAM-Chem) and the Data Assimilation Research Testbed (DART). With regard to KORUS-AQ data, CO is underestimated by 42 % in the control run and by 12 % with the MOPITT assimilation run. The inversion suggests an underestimation of anthropogenic CO sources in many regions, by up to 80 % for northern China, with large increments over the Liaoning Province and the North China Plain (NCP). Yet, an often-overlooked aspect of these inversions is that correcting the underestimation in anthropogenic CO emissions also improves the comparison with observational O3 datasets and observationally constrained box model simulations of OH and HO2. Running a CAM-Chem simulation with the updated emissions of anthropogenic CO reduces the bias by 29 % for CO, 18 % for ozone, 11 % for HO2, and 27 % for OH. Longer-lived anthropogenic VOCs whose model errors are correlated with CO are also improved, while short-lived VOCs, including formaldehyde, are difficult to constrain solely by assimilating satellite retrievals of CO. During an anticyclonic episode, better simulation of O3, with an average underestimation of 5.5 ppbv, and a reduction in the bias of surface formaldehyde and oxygenated VOCs can be achieved by separately increasing by a factor of 2 the modeled biogenic emissions for the plant functional types found in Korea. Results also suggest that controlling VOC and CO emissions, in addition to widespread NOx controls, can improve ozone pollution over East Asia.

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Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-28019-2014 ◽

2014 ◽

Vol 14 (20) ◽

pp. 28019-28077

Author(s):

K. Ding ◽

J. Liu ◽

A. Ding ◽

Q. Liu ◽

T. L. Zhao ◽

...

Keyword(s):

East Asia ◽

Biomass Burning ◽

North China Plain ◽

North China ◽

Free Troposphere ◽

Transport Pathways ◽

Upper Troposphere ◽

The North ◽

The North China Plain ◽

The Sichuan Basin

Abstract. East Asia has experienced rapid development with increasing CO emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in East Asia from 2003 to 2005 are examined with spaceborne Measurements Of Pollution In The Troposphere (MOPITT) data, in combination with aircraft measurements from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. High CO abundances of 300–550 ppbv were observed in MOZAIC data in the free troposphere during these episodes. These are among the highest CO abundances documented at these altitudes. Correspondingly, elevated CO was shown in MOPITT daytime data in the middle to upper troposphere in the 2003 case, mostly in the lower to middle troposphere in the 2004 case, and in the upper troposphere in the 2005 case. Through analyses of the simulations from a chemical transport model GEOS-Chem and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases. In the 2003 case, CO from large forest fires near Lake Baikal dominated the elevated CO, which had been rapidly transported upward by a~frontal system from the fire plumes. In the 2004 case, anthropogenic CO from the North China Plain experienced frontal lifting and mostly reached ~ 700 hPa near the East China Sea, while CO from biomass burning from Indochina experienced orographic lifting, leeside-trough induced convection, and frontal lifting through two separate transport pathways, leading to two distinct CO enhancements around 700 hPa and 300 hPa. In the 2005 case, high CO of ~ 300 ppbv, observed in the MOZAIC data around 350 hPa, originated from the anthropogenic source over the vicinity of the Sichuan basin and biomass burning from Indochina, after convection and strong frontal lifting. These cases show that topography affects vertical transport of CO in East Asia via different ways, including orographic uplifting over the Hengduan Mountains, assisting frontal lifting in the North China Plain, and facilitating convection in the Sichuan basin. In particular, topography-induced leeside troughs over Indochina lead to strong convection that assisted CO uplifting to the upper troposphere. This study shows that the new daytime MOPITT near-infrared (NIR) and thermal-infrared (TIR) data (version 5 or above) have enhanced vertical sensitivity and may help qualitative diagnosis of vertical transport processes in East Asia.

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