Mechanism of spring high oxidant episode— A meteorological analysis in and around the Hokuriku district, Japan

Kato, Hisashi; Fujita, Shin-ichi; Nishinomiya, Shaw

doi:10.1016/0960-1686(90)90237-h

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…In Japan, the springtime ozone maximum is usually attributed to significant contribution of the vertical stratospheric ozone intrusion to the ground level ozone. Kato et al [1990], Ueda and Carmichael [1995] conducted field observations and performed numerical simulation for the observed springtime ozone episodes. They concluded that the combined effects of the photochemical ozone and the high background ozone of stratospheric origin are the causes of the episodes.…”

Section: Resultsmentioning

confidence: 99%

Effects of Asian air pollution transport and photochemistry on carbon monoxide variability and ozone production in subtropical coastal south China

Chan

Lam

et al. 2002

J.‐Geophys.‐Res.

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[1] Surface ozone and carbon monoxide (CO) measured from a relatively remote coastal station in Hong Kong are analyzed to study the effects of pollutant transport and associated ozone production on CO and ozone variations in the subtropical south China region. CO and ozone concentrations show a common minimum in summer and in the maritime air masses from the South China Sea and Pacific Ocean. They have higher values in other seasons and in the continental air masses that have passed over mainland Asia and the East Asian coast. CO shows the maximum monthly median of 457-552 ppbv in winter while ozone shows a maximum of 40-50 ppbv in autumn and a distinct peak of 41-43 ppbv in spring. The CO concentrations especially in the continental air masses (median of 277 to 428 ppbv) are very high when compared with measurements in most parts of the world. This suggests that the south China region is under the strong influence of pollutant transport from the Asian continent and East Asian coast. Ozone and CO show strong positive correlations in the polluted maritime air masses and from late spring to early autumn (May-September) with the linear regression slopes of the ozone-CO plot from 0.08 to 0.22 (with respective standard errors from 0.01 to 0.03). The strong correlations and slopes plus the high CO levels indicate that there is substantial ozone production from pollution in the polluted maritime air masses and in the late spring to early autumn period.

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Section: Resultsmentioning

confidence: 99%

Effects of Asian air pollution transport and photochemistry on carbon monoxide variability and ozone production in subtropical coastal south China

Chan

Lam

et al. 2002

J.‐Geophys.‐Res.

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“…During spring, there is an increasing frequency of stratospheric intrusion events compared with other seasons (Danielson, 1968;Chung and Dunn, 1985;Kato et al, 1990). It has been suggested that the spring maximum is caused by a gradual accumulation of ozone and precursors over the winter when the lifetimes of ozone and precursors are significantly longer than in summer (Penkett et al, 1993;Liu et al, 1987).…”

Section: Introductionmentioning

confidence: 97%

The Characteristics of Tropospheric Ozone Seasonality Observed from Ozone Soundings at Pohang, Korea

Kim

Lee

2006

Environ Monit Assess

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This paper presents the first analysis of vertical ozone sounding measurements over Pohang, Korea. The main focus is to analyze the seasonal variation of vertical ozone profiles and determine the mechanisms controlling ozone seasonality. The maxima ozone at the surface and in the free troposphere are observed in May and June, respectively. In comparison with the ozone seasonality at Oki (near sea level) and Happo (altitude of 1840 m) in Japan, which are located at the same latitude as of Pohang, we have found that the time of the ozone maximum at the Japanese sites is always a month earlier than at Pohang. Analysis of the wind flow at the surface shows that the wind shifts from westerly to southerly in May over Japan, but in June over Pohang. However, this wind shift above boundary layer occurs a month later. This wind shift results in significantly smaller amounts of ozone because the southerly wind brings clean wet tropical air. It has been suggested that the spring ozone maximum in the lower troposphere is due to polluted air transported from China. However, an enhanced ozone amount over the free troposphere in June appears to have a different origin. A tongue-like structure in the time-height cross-section of ozone concentrations, which starts from the stratosphere and extends to the middle troposphere, suggests that the ozone enhancement occurs due to a gradual migration of ozone from the stratosphere. The high frequency of dry air with elevated ozone concentrations in the upper troposphere in June suggests that the air is transported from the stratosphere. HYSPLIT trajectory analysis supports the hypothesis that enhanced ozone in the free troposphere is not likely due to transport from sources of anthropogenic activity.

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“…This spring ozone maximum has two possible causes: It may be due to intrusion of stratospheric ozone, or it may be of anthropogenic origin. Stratospheretroposphere exchanges accompanying active cyclones and then the descent of stratospheric air following anticyclones have been reported to enhance springtime ozone concentrations at the surface (Wakamatsu et al, 1989;Murao et al, 1990aMurao et al, , 1990bKato et al, 1990;Oltmans and Levy, 1992;Carmichael et al, 1998).…”

Section: Springtime Ozone Maximummentioning

confidence: 99%

Characterization of ozone in the middle troposphere over Japan from 6-year observation at the summit of Mount Fuji (3776m)

Tsutsumi¹

2018

Pap. Meteor. Geophys.

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Tropospheric ozone was continuously measured at the summit of Mt. Fuji (3776 m a.s.l.) for 6 years (1992-1998). Although mountain sites are usually influenced by mountain-valley winds, the small variance of the averaged diurnal ozone variation (0.77 ppbv) indicates that air at the summit of Mt. Fuji was hardly influenced by the boundary layer. Thus, the observations suggest some characteristic features of ozone in the middle troposphere over Japan. Annual variation at the summit was characterized by a bimodal seasonal cycle with maxima in May and October and minima in August and December. The summer minimum, which causes the seasonal cycle to be bimodal, resulted from summertime dominance of ozone-depleted maritime air at the summit. In June, however, air with a low water-vapor mixing ratio, high potential vorticity (PV), and enhanced ozone (> 60 ppbv) was occasionally observed; these characteristics suggest that this air mass originated in the stratosphere or the upper troposphere. The small ozone variation during winter may be due to the suppression of its photochemical destruction and strong zonal winds, which cause the ozone distribution to be zonally homogeneous in the middle troposphere in winter. In addition, the infrequency of ozone intrusions from the stratosphere in winter may also contribute to the small wintertime variation. The annual course of daily mean ozone at the summit was synchronized with that of clear-sky solar radiation from late autumn to early spring, and both minima occurred in late December; this correspondence suggests that solar radiation controls observed ozone levels at the summit during this part of the year. In spring, daily mean ozone increased simultaneously with daily solar radiation, and the ozone concentration was not correlated with PV; this result suggests that the spring ozone maximum results mainly from photochemical ozone production. However, the possibility that indirect stratospheric ozone intrusions or aged stratospheric ozone contribute to the spring ozone maximum cannot be ruled out. The ozone concentration at the summit of Mt. Fuji increased during the 6-year observation period at the rate of 0.49 ppbv year −1 , but the increasing trend was not significant at the 95% confidence level.

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Mechanism of spring high oxidant episode— A meteorological analysis in and around the Hokuriku district, Japan

Cited by 11 publications

References 8 publications

Effects of Asian air pollution transport and photochemistry on carbon monoxide variability and ozone production in subtropical coastal south China

Effects of Asian air pollution transport and photochemistry on carbon monoxide variability and ozone production in subtropical coastal south China

The Characteristics of Tropospheric Ozone Seasonality Observed from Ozone Soundings at Pohang, Korea

Characterization of ozone in the middle troposphere over Japan from 6-year observation at the summit of Mount Fuji (3776m)

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