Trace Gas Measurements in India S. Lal Physical Research Laboratory, Ahmedabad, India Indo-US Workshop Chennai July 12-16, 2006

Background The tropical atmosphere is a vast natural photochemical laboratory with intense solar radiation and higher amount of water vapour. It is also a region of strong upwelling and convection. Anthropogenic emissions of various trace gases are increasing due to rapid industrialization and urbanization specially in the Asian region. Increasing levels of pollutants (gases and particulate matter) can perturb the natural chemistry, radiation balance and can cause environmental and climatic changes.

IPCC 2001

Anthropogenic Emissions of Pollutants

China India Indonesia South Korea Japan NOx emissions during (Gg NO 2 /yr) Van Aardenne (1999) AE Anthropogenic emissions of NOx from Asia Industrial & power plants : 45% Transportation sector : 37% Biomass burning : 18% Streets et al. 2003, JGR

Tropospheric Ozone Production Loss  Balance  O 3 + h  O( 1 D) + O 2 HO + O 3  HO 2 + O 2 HO 2 + O 3  OH + 2O 2 NO + O 3  NO 2 + O 2 Dry Deposition Similar set of reactions for CH 4 and NMHCs

Environmental impact of O 3 exposure: Crop yields Human Health Lungs Respiration

Ozone is the only source of OH radicals which are known as ‘detergent’ in the troposphere. O 3 + h -> O( 1 D) + O 2 O( 1 D) + H 2 O -> 2OH Chemistry Radiation forcing Forster and Shine, 1997 Role in Chemistry and Climate

Mount Abu 1700m Gadanki Port Blair Trivandrum Ahmedabad ISRO-GBP : Monitoring of Ozone and Related Gases

An increase in surface level ozone concentration from to at 0.5%/year is found over Ahmedabad. Efficiency of O 3 production more at rural sites than at urban sites. Lower net surface ozone production (0.15 O 3 /CO) over the Indian region as compared to in US or Europe (0.35 O 3 /CO). Comparison with a 3D Model Model of Atmospheric Transport and Chemistry (MATCH) Naja and Lal, GRL 1996 Lal and Lawrence, GRL 2001

Measurements over the Bay of Bengal

Percentage compositions of C 2 -C 4 NMHCs At Ahmedabad, local emissions of various NMHCs play very important role while at Mt. Abu transport from the source regions is a key parameter in their distributions. Among all the NMHCs measured, propane dominates at Ahmedabad while it is ethane at Mt. Abu. Sahu and Lal, AE, 2006

NPL & CRRI PRL IITM NRSA AU IISc & AntpU SPL Routes For Feb Shadnagar/Hyderabad Distance Travelled ~ km Number of Stations ~ 150 Number of Participants ~ 50 ISRO GBP Land Campaign I - Feb. 2004

ISRO GBP Land Campaign II – Dec Indian Institutes and Universities participated

Transport and Transformation of Pollutants Higher levels of ozone at rural/ remote sites. Efficiency of O3 production more at rural sites than at urban sites. Dominance of fossil fuel combustion related emissions based on measured NMHCs and other gases.

Higher levels of ozone at rural/ remote sites. Dominance of Fossil fuel combustion related emissions based on first time measured NMHCs and other gases. No clear diurnal variation during foggy days LC-II, Dec Transport and transformation of pollutants

Increasing anthropogenic emissions : Impact on chemistry and climate GOME satellite

Akimoto (2003), Science

Brasseur et al., GRL 1998 Past and future changes in global tropospheric ozone NH Mid lat : Boundary Layer : 80 % (15 ppb) Free Troposphere : % (20-40 ppb) 1850 to to 2050 IPCC scenario IS92a ‘medium case’ CO : 1.7 fold increase NOx : 2.1 fold increase NMHCs : 2.4 fold increase Large (3-7 fold) changes in SE Asia and Africa

Focus of tropospheric research on chemistry-climate interactions over the Asian region Prather et al JGR 2003 “Understanding the processes that connect emissions (source precursors) to abundances and abundances to the climate forcings are essential for an accurate prediction of the future climate and an assessment of the impact of climate change and variations on the earth system.” SPARC-IGAC Stratospheric Processes and their Role in the Climate 2100

Future Plans

ISRO GBP - Ground based monitoring stations Longterm measurements of CO, NOx, O 3, SO 2, HCs etc will be made at selected sites to study their emission fluxes and changes in their concentrations. Mountain sites : Mt. Abu Nainital (Towers will also be useful) Remote/ : Port Blair Rural sites Gadanki Thumba Shillong Roorkee Urban sites : Ahmedabad Kanpur Bhubneswar/Visakhapatnam/Chennai Detailed measurements of trace gases will be made along with meteorological parameters (temperature, humidity, winds, solar and IR radiation etc.). Also these measurements will be supported by chemical-transport 3D models.

Satellite based measurements of key pollutants (like CO, O 3, aerosol) are needed to study future changes in this region. Low inclination satellite Limb and nadir viewing High resolution spectrometer  m. Trace gases measurements from space

Summary In view of the increasing levels of trace gases due to anthropogenic activities, there is a need to know their emissions and their impacts on environment and future climate. We plan to study levels and changes occurring due to natural as well as anthropogenic processes in different regions of India using ground based, aircraft and satellite based measurements. These observation will be supported by 3D model simulations.

Thanks