Seasonal stratospheric intrusion of ozone in the upper troposphere over India

Chakraborty, T.; Beig, G.

doi:10.5194/angeo-28-2149-2010

Cited by 31 publications

(20 citation statements)

References 36 publications

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“…Mandal et al (1998) analysed observations from ozone-sondes and an MST radar, and attributed the enhanced ozone mixing ratios in the upper troposphere to STT through the indistinct tropopause over southern India. Fadnavis et al (2010) combined satellite-borne measurements (TES and MLS) with simulations performed by the MOZART model and showed significant influences of STT over India, in particular during winter and spring/premonsoon. Venkat used satellite observations to estimate the effect of STE associated with tropical cyclones over the northern Indian Ocean.…”

Section: Introductionmentioning

confidence: 99%

Secondary ozone peaks in the troposphere over the Himalayas

et al. 2017

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Abstract. Layers with strongly enhanced ozone concentrations in the middle-upper troposphere, referred to as secondary ozone peaks (SOPs), have been observed in different regions of the world. Here we use the global ECHAM5/MESSy atmospheric chemistry model (EMAC) to (i) investigate the processes causing SOPs, (ii) explore both their frequency of occurrence and seasonality, and (iii) assess their effects on the tropospheric ozone budget over the Himalayas. The vertical profiles of potential vorticity (PV) and a stratospheric ozone tracer (O 3 s) in EMAC simulations, in conjunction with the structure of SOPs, suggest that SOPs over the Himalayas are formed by stratosphereto-troposphere transport (STT) of ozone. The spatial distribution of O 3 s further shows that such effects are in general most pronounced in the northern part of India. Model simulated ozone distributions and backward air trajectories show that ozone rich air masses, associated with STT, originate as far as northern Africa and the North Atlantic Ocean, the Middle East, as well as in nearby regions in Afghanistan and Pakistan, and are rapidly (within 2-3 days) transported to the Himalayas. Analysis of a 15-year (2000-2014) EMAC simulation shows that the frequency of SOPs is highest during the pre-monsoon season (e.g. 11 % of the time in May), while no intense SOP events are found during the July-October period. The SOPs are estimated to enhance the tropospheric column ozone (TCO) over the central Himalayas by up to 21 %.

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Section: Introductionmentioning

confidence: 99%

Secondary ozone peaks in the troposphere over the Himalayas

et al. 2017

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“…The ozone concentrations in the extra-tropical lower stratosphere show a maximum in late winter/early spring as driven by the Brewer-Dobson circulation (e.g., Fortuin and Kelder, 1998;Metz et al, 2005). Fadnavis et al (2010) indicated ozone stratospheric intrusion during winter and pre-monsoon season over the Indian re- (Fig. 13).…”

Section: Stratosphere-troposphere Exchangementioning

confidence: 99%

Tropospheric ozone maxima observed over the Arabian Sea during the pre-monsoon

Jia¹,

Ladstätter-Weißenmayer²,

Hou

et al. 2017

Atmos. Chem. Phys.

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Abstract. An enhancement of the tropospheric ozone column (TOC) over Arabian Sea (AS) during the pre-monsoon season is reported in this study. The potential sources of the AS spring ozone pool are investigated by use of multiple data sets (e.g., SCIAMACHY Limb-Nadir-Matching TOC, OMI/MLS TOC, TES TOC, MACC reanalysis data, MOZART-4 model and HYSPLIT model). Three-quarters of the enhanced ozone concentrations are attributed to the 0-8 km height range. The main source of the ozone enhancement is considered to be caused by long-range transport of ozone pollutants from India ( ∼ 50 % contributions to the lowest 4 km, ∼ 20 % contributions to the 4-8 km height range), the Middle East, Africa and Europe (∼ 30 % in total). In addition, the vertical pollution accumulation in the lower troposphere, especially at 4-8 km, was found to be important for the AS spring ozone pool formation. Local photochemistry, on the other hand, plays a negligible role in producing ozone at the 4-8 km height range. In the 0-4 km height range, ozone is quickly removed by wet deposition. The AS spring TOC maxima are influenced by the dynamical variations caused by the sea surface temperature (SST) anomaly during the El Niño period in 2005 and 2010 with a ∼ 5 DU decrease.

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“…The DO 3 /DCO measured within the O3R corresponds to photochemically aged tropospheric air. Further northwestwards (608Á64.58E near the Northern Hemisphere SWJ) O 3 CO are highly anticorrelated (R 0 (0.73) with an almost linear relationship and a large negative slope ( (1.3 ppbv/ppbv) indicating the import of stratospheric air-masses as the most likely dominant process controlling the O 3 distribution (Zahn et al, 2002;Fadnavis et al, 2010 …”

Section: Mozaic Air-mass Characterisationmentioning

confidence: 99%

An upper tropospheric ‘ozone river’ from Africa to India during the 2008 Asian post-monsoon season

Tocquer

Barret

Mari

et al. 2015

Tellus B: Chemical and Physical Meteorology

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A B S T R A C TWe have used ozone data from the Infrared Atmospheric Sounding Interferometer to follow an event of ozoneenriched air-masses in the upper troposphere from eastern Africa to northern India. The ozone transport (hereafter called 'ozone river' or O3R) occurred during the Asian post-monsoon season in 2008 and was associated with Rossby wave propagation. The persistence of the O3R in a narrow channel was confirmed by MOZAIC airborne data over the northwestern Indian coast. The regions of origin of the O3R were identified by a transport analysis based on the Lagrangian model FLEXPART. The Lagrangian simulations combined with potential vorticity fields indicate that stratospheric intrusions are not likely to be the most important contributor to the observed O 3 enhancements. A high-resolution Eulerian model, Meso-NH, with tagged tracers was used to discriminate between African biomass burning, lightnings and Indian anthropogenic pollution as potential sources of precursors for the O3R. Lightning NOx emissions, associated with convective clouds over Africa, were found to be the principal contributor to the ozone enhancement over the Indian Ocean taking advantage of a northeastward jet. This case study illustrates African lightning emissions as an important source for enhanced O 3 in the upper troposphere over the Indian Ocean region during the post-monsoon season.

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Seasonal stratospheric intrusion of ozone in the upper troposphere over India

Cited by 31 publications

References 36 publications

Secondary ozone peaks in the troposphere over the Himalayas

Secondary ozone peaks in the troposphere over the Himalayas

Tropospheric ozone maxima observed over the Arabian Sea during the pre-monsoon

An upper tropospheric ‘ozone river’ from Africa to India during the 2008 Asian post-monsoon season

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