Variability in the distribution of ozone over land and marine regions in the Indian region S. Lal 1 , S. Venkataramani 1 , S. Srivastava 1 , S. Gupta 1 and M. Naja 2 1 Physical Research Laboratory, Ahmedabad, India 2 Aryabhatta Research Institute of Observational Sciences, Nainital, India shyam@prl.res.in
Current focus of tropospheric research is on chemistry- climate interactions especially over the Asian region Akimoto (2003) Science Sheel et al., AE, 2010 NOx emissions during 1990-2020 Monthly mean surface ozone (Gg NO 2 /yr), Streets et al. JGR 2003 increase from 2000 to 2100 1990 2000 2010 2020 based on average results of China 8273 13719 21906 32364 10 models. India 3481 5615 10842 22824 Prather et al., JGR 2003
Average Seasonal Wind Streamlines Winter DJF MAM SON JJA
Study of ozone and related trace gases at Ahmedabad Nainital New Delhi Mt. Abu Ahmedabad Time (IST) Tirupati Port Blair Ooty Thumba
Surface ozone at Ahmedabad – Longterm Trends 60 1400 hrs 1991 - 93 Average ozone (ppbv) 1954 - 55 40 20 Aver erage ge ozone mixing r one mixing ratio io 0 0 4 8 12 16 20 24 incr increased eased fr from om 14.7 14.7 ppb ppbv Time (IST) 60 dur during 1954 ing 1954-55 t 55 to o 25.3 25.3 ppb ppbv Monthly Average ozone (ppbv) 1400 hrs 1954 - 55 during 1 dur ing 1991 991-93, r 93, result esulting ing in in 1991 - 93 40 a linear a linear incr increase ease of of ~ 1.4%/y 1.4%/year ear 20 0 0 1 2 3 4 5 6 7 8 9 10 11 12 Month Naja and Lal, GRL , 1996
Diurnal variation of ozone at Mt. Abu (24.6N, 72.7E, 1680m amsl ) Mt Abu (1993-2000) Autumn (SON) [a] 4 Winter (DJF) Mauna Loa 2 O 3 (ppbv) 0 Mt Abu Observatory in the early 1990’s -2 -4 Spring (MAM) [b] 4 Summer (J_A) Mauna Loa 2 O 3 (ppbv) 0 -2 -4 0 6 12 18 24 Time (LST) Autumn and Winter : Winds from north Spring and Summer : Winds from south-west and south Naja et al., AE 2003
Regional and Local effects ~ 12-15 ppbv Monthly avg at Mt Abu (1993-97) Day time avg (12-14 hrs) at Ahmedabad (1991-95) Regional Best fit line for day time avg (12-14 hrs) at Ahmedabad Contribution Night time avg (01-03 hrs) at Ahmedabad (1991-95) ~ 5-10 ppbv Local (Amd) 100 Contribution 80 Avg Ozone (ppbv) 60 40 20 0 J F M A M J J A S O N D Months
Ozone at Mt. Abu (24.6N, 72.7E) and Nainital (29.4N,79.4E) Hourly Average (NTL - 2006) Nainital - 2006 Hourly Average (NTL - 2007) Nainital - 2007 Hourly Average (NTL - 2008) Nainital - 2008 Monhtly Average (Mt Abu) Maximum ozone : 100 100 Average Ozone (ppbv) 80 80 Mt. Abu - Autumn/Winter 60 60 Nainital - Spring/Summer 40 40 20 20 0 0 20 Startospheric Ozone European Emissions Model derived 15 South Asia Emissions 10 contributions (in ppbv) 5 for Nainital . 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Variations and levels of ozone and related trace gases are different over different parts of India suggesting diverse regional emission sources Kumar et al., JGR, 2010
CO-NOx Relation 40 30 CO/NOx 20 10 0 AHMEDABAD HISAR KANPUR CHINA US EUROPE Japan The slope (∆CO/∆NOx) is related to primary emission sources of these species. In high temperature combustion processes (e.g., use of fossil fuel in vehicles and power plants) these slope values are lower than those emitted from biofuel and biomass burning These results indicate that emission from biofuel combustion and biomass burning play major role in the observed distributions of various trace gases in India.
Ver tical distribution of ozone over Ahmedabad (June 2003- July 2007) Balloon 25 m Parachute Radio sonde ECC Ozone sonde (GPS) Effects of : Total ~ 80 balloon flights Regional Pollution - Spring and summer seasons Longrange Transport – Spring season in the free troposphere Marine - Monsoon season in the BL
Study of ozone and meteorological parameters over Bay of Bengal (BoB) and Arabian Sea (AS) Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) 30 25 Bhubneswer 9 My 5 May INDIA 4 My 20 29 A 20 M 22 M o N) 28 A 24 M Latitude ( 19 M 7 My 3 My Goa 15 Arabian Sea 26 M 28 M Bay of Bengal Chennai 27 A 30 A 30 M 2 A 1 A 25 A 23 A 6 A Kochi 10 4 A Trivandrum 19 A 21 A 12 A 8 A 5 10 A 0 55 60 65 70 75 80 85 90 95 Longitude ( o E) Bay of Bengal (18 March to 13 April,06) Arabian Sea (18 April to 11 May,06) 29 Ozone and radio sondes
Intrusion of land plume over North Bay of Bengal (N-BoB) and North Arabian Sea (N-AS)- ICARB 2006 S-BoB N-BoB NBoB - SBoB N-AS S-AS NAS – SAS Potential Source Contribution Function (PSCF) analysis Transport of ozone rich layer (60-90 ppbv) over N-BoB attributed to advection of air from Indo-Gangetic Plain. Srivastava et al., JGR (in press)
Measurements of ozone and related trace gases in different regions : A network of environmental observatories in India under ISRO GBP Nainital 29.4N,79.4E ~2.0 km Kullu Nainital Mt. Abu Agra Kanpur 24.6N,72.6E Mt. Abu Shillong ~1.7 km Kolkata Ahmedabad Bhubneshwar Nagpur Vishakhapatnam Hyderabad Ooty Mt Abu Observatory in the early 1990’s Anantpur Gadanki 11.4N,76.7E Port Blair ~ 2.5 km Thalassery Ooty Thumba
Summary : • Tropical Asian region - a natural photochemical laboratory. • Chemical changes are occurring due to rapid industrialization and economic growth. • Emission characteristics and transport pathways differ from region to region and from season to season. • Surrounding marine regions affected by transport for the continental polluted air. • There is a need for understanding types of emission sources, their budgets and chemical and transport processes for predicting future changes in this region.
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