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On the processes influencing the vertical distribution of ozone over the central Himalayas: Analysis of yearlong ozonesonde observations
https://orcid.org/0000-0002-8840-5699
https://orcid.org/0000-0002-4597-1690
https://orcid.org/0000-0002-3135-9556
Abstract First yearlong (2011) balloon-borne measurements of ozone vertical distribution (EN-SCI 2ZV7 ECC Ozonesonde) and meteorological parameters (iMet-1-RSB 403 MHz GPS Radiosonde) over Nainital (79.5°E, 29.4°N, 1958 m amsl) in the central Himalayas are presented. Lower tropospheric ozone shows a prominent seasonality with highest levels during spring (∼70–110 ppbv in May) and lowest levels during summer-monsoon (∼20–50 ppbv), which is consistent with the ground-based observations. The lower tropospheric ozone minimum coincides with highest values of relative humidity (80–100%) during the summer-monsoon. However, ozone mixing ratios in the middle-upper troposphere show less pronounced and different seasonality. Influences of subtropical jets are observed (wind speed: ∼40–80 m s−1) in the middle-upper troposphere, particularly during winter. A stratospheric intrusion event during winter is observed, which enhances the ozone levels by ∼180% in the middle-upper troposphere. A noticeable feature of secondary ozone peaks (∼140–250 ppbv) is observed in the middle troposphere (∼8–12 km), more frequently during spring. Ozone levels in 2–4 km altitude range are higher by 19.9 ± 4.6 ppbv during the springtime high fire activity period over the northern India. Moreover, the lower tropospheric ozone levels over Nainital during spring are found to be considerably (∼30 ppbv) higher than those over Ahmedabad in the western India. This ozone enhancement is attributed mainly to the regional pollution of the Indo-Gangetic Plain (IGP) supplemented with the northern Indian biomass burning. It is suggested that regional photochemistry and biomass burning processes play controlling role in the lower troposphere, while, the middle-upper tropospheric variations are driven by dynamical processes including advection and stratospheric intrusion.
Highlights First yearlong ozonesonde-radiosonde observations over the central Himalayas. Stratospheric intrusion enhances ozone significantly in middle-upper troposphere. Influence of northern Indian biomass burning on ozone distribution. Invaluable data for evaluation of models and satellite products.
On the processes influencing the vertical distribution of ozone over the central Himalayas: Analysis of yearlong ozonesonde observations
https://orcid.org/0000-0002-8840-5699
https://orcid.org/0000-0002-4597-1690
https://orcid.org/0000-0002-3135-9556
Abstract First yearlong (2011) balloon-borne measurements of ozone vertical distribution (EN-SCI 2ZV7 ECC Ozonesonde) and meteorological parameters (iMet-1-RSB 403 MHz GPS Radiosonde) over Nainital (79.5°E, 29.4°N, 1958 m amsl) in the central Himalayas are presented. Lower tropospheric ozone shows a prominent seasonality with highest levels during spring (∼70–110 ppbv in May) and lowest levels during summer-monsoon (∼20–50 ppbv), which is consistent with the ground-based observations. The lower tropospheric ozone minimum coincides with highest values of relative humidity (80–100%) during the summer-monsoon. However, ozone mixing ratios in the middle-upper troposphere show less pronounced and different seasonality. Influences of subtropical jets are observed (wind speed: ∼40–80 m s−1) in the middle-upper troposphere, particularly during winter. A stratospheric intrusion event during winter is observed, which enhances the ozone levels by ∼180% in the middle-upper troposphere. A noticeable feature of secondary ozone peaks (∼140–250 ppbv) is observed in the middle troposphere (∼8–12 km), more frequently during spring. Ozone levels in 2–4 km altitude range are higher by 19.9 ± 4.6 ppbv during the springtime high fire activity period over the northern India. Moreover, the lower tropospheric ozone levels over Nainital during spring are found to be considerably (∼30 ppbv) higher than those over Ahmedabad in the western India. This ozone enhancement is attributed mainly to the regional pollution of the Indo-Gangetic Plain (IGP) supplemented with the northern Indian biomass burning. It is suggested that regional photochemistry and biomass burning processes play controlling role in the lower troposphere, while, the middle-upper tropospheric variations are driven by dynamical processes including advection and stratospheric intrusion.
Highlights First yearlong ozonesonde-radiosonde observations over the central Himalayas. Stratospheric intrusion enhances ozone significantly in middle-upper troposphere. Influence of northern Indian biomass burning on ozone distribution. Invaluable data for evaluation of models and satellite products.
On the processes influencing the vertical distribution of ozone over the central Himalayas: Analysis of yearlong ozonesonde observations
https://orcid.org/0000-0002-8840-5699
https://orcid.org/0000-0002-4597-1690
https://orcid.org/0000-0002-3135-9556
Abstract First yearlong (2011) balloon-borne measurements of ozone vertical distribution (EN-SCI 2ZV7 ECC Ozonesonde) and meteorological parameters (iMet-1-RSB 403 MHz GPS Radiosonde) over Nainital (79.5°E, 29.4°N, 1958 m amsl) in the central Himalayas are presented. Lower tropospheric ozone shows a prominent seasonality with highest levels during spring (∼70–110 ppbv in May) and lowest levels during summer-monsoon (∼20–50 ppbv), which is consistent with the ground-based observations. The lower tropospheric ozone minimum coincides with highest values of relative humidity (80–100%) during the summer-monsoon. However, ozone mixing ratios in the middle-upper troposphere show less pronounced and different seasonality. Influences of subtropical jets are observed (wind speed: ∼40–80 m s−1) in the middle-upper troposphere, particularly during winter. A stratospheric intrusion event during winter is observed, which enhances the ozone levels by ∼180% in the middle-upper troposphere. A noticeable feature of secondary ozone peaks (∼140–250 ppbv) is observed in the middle troposphere (∼8–12 km), more frequently during spring. Ozone levels in 2–4 km altitude range are higher by 19.9 ± 4.6 ppbv during the springtime high fire activity period over the northern India. Moreover, the lower tropospheric ozone levels over Nainital during spring are found to be considerably (∼30 ppbv) higher than those over Ahmedabad in the western India. This ozone enhancement is attributed mainly to the regional pollution of the Indo-Gangetic Plain (IGP) supplemented with the northern Indian biomass burning. It is suggested that regional photochemistry and biomass burning processes play controlling role in the lower troposphere, while, the middle-upper tropospheric variations are driven by dynamical processes including advection and stratospheric intrusion.
Highlights First yearlong ozonesonde-radiosonde observations over the central Himalayas. Stratospheric intrusion enhances ozone significantly in middle-upper troposphere. Influence of northern Indian biomass burning on ozone distribution. Invaluable data for evaluation of models and satellite products.
On the processes influencing the vertical distribution of ozone over the central Himalayas: Analysis of yearlong ozonesonde observations
Ojha, N. (author) / Naja, M. (author) / Sarangi, T. (author) / Kumar, R. (author) / Bhardwaj, P. (author) / Lal, S. (author) / Venkataramani, S. (author) / Sagar, R. (author) / Kumar, A. (author) / Chandola, H.C. (author)
Atmospheric Environment ; 88 ; 201-211
2014-01-13
11 pages
Article (Journal)
Electronic Resource
English