AEROSOLS. DR S D ATTRI DY. DIRECTOR GENERAL INDIA METEOROLOGICAL DEPARTMENT NEW DELHI (INDIA)

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1 AEROSOLS DR S D ATTRI DY. DIRECTOR GENERAL INDIA METEOROLOGICAL DEPARTMENT NEW DELHI (INDIA) sdattri@gmail.com; sd.attri@imd.gov.in 9 th Meeting of the CAS MG, Geneva, April, 2014

2 WHY STUDY AEROSOLS? Reduce/Increase GHG s Warming, Affect Cloud and Rain, Interfere with Remote Sensing Active in Atmospheric Chemistry, Supply Minerals to Ocean Biosphere, Affect Well- Being of Organisms on both Land and Sea: Contain Spores, Microbes and Viruses, Acids and other stuff.

3 SIGNIFICANCE OF AEROSOLS One of the most significant and uncertain aspects of climate change projections, regarding both their direct and indirect effects. Play a significant role in human health issues and in environmental effects caused by biomass burning, dust storms and volcanic eruptions and at shorter timescales in NWP.

4 CAIPEEX IITM J. R. Kulkarni 4 PNAS Nadine Unger of NASA's Goddard Institute for Space Studies (GISS) in New York City offers a more intuitive way to understand what's changing the Earth's climate. Rather than analyzing impacts by chemical species, scientists have analyzed the climate impacts by different economic sectors.

5 Observations Radiation Aerosols Surface Met. Upper Air Met. Atmospheric Chemistry GHG Climate Change Fluxes Soil temperature Ecosystem Water flowdischarge Crop Related Observations Evaporation Glaciers Ocean related parameters Cryosphere Health data

6 AR-3 AR-4 The RF of the total aerosol effect in the atmosphere, which includes cloud adjustments due to aerosols, is 0.9 [ 1.9 to 0.1] Wm 2 (medium confidence), and results from a negative forcing from most aerosols and a positive contribution from BC absorption of solar radiation. (Source: IPCC, AR5) Radiative Forcing Estimates AR-5

7 EFFECTS OF AEROSOL Direct effect: scattering/absorbing sunlight Semi-direct effect: aerosol absorption heats atmospheric layer warmer air lower relative humidity less/no cloud Indirect effect: modifying cloud properties brightness (first) effect lifetime (second) effect

8 TYPES AND SOURCES OF AEROSOLS Type Sources Dust Desert, bare soil Sulfuric aerosol Fossil fuel burning, ocean phytoplankton Sea salt Ocean spray Smoke Forest fires Organic carbon Fossil fuel burning, forest fires Natural Volcanic dust Sea salt Dust Sources Forest fires Anthropogenic Sources

9 LIFETIMES OF AEROSOLS Aitken nuclei hours to days Accumulation mode weeks Coarse mode hours to days Ultrafine minutes to hours

10 GLOBAL PARTICLE PRODUCTION (SEINFELD AND PANDIS) Source Estimate Flux (Tg/yr) Particle Size Category Primary Soil dust (mineral aerosol) Mainly coarse Sea salt Coarse Volcanic dust Coarse Biological debris Coarse Secondary Sulfates from biogenic gases Fine Sulfates from volcanic SO Fine Organic matter from biogenic VOC Fine Nitrates from NOx Fine and coarse Total Natural Best estimate 3100 Anthropogenic Primary Industrial dust etc. (except soot) Fine and coarse Soot 5-20 Mainly fine Secondary Sulfates from SO Fine Biomass burning Fine Nitrates from NOx Mainly coarse Organics from anthropogenic VOC 5-25 Fine Total anthropogenic Best estimate 450 Total Best estimate 3600

11 AEROSOLS VERSUS GHG S Aerosols are wide- spread, localized, transitory and highly variable on all space and time scales Atmospheric GHG s are globally distributed in a vastly more homogeneous manner and vary in time mostly on seasonal and longer time scales. Distributions of CO 2 and N 2 O are spatially homogeneous due to a long lifetime. A - 11

12 PRESENT MAIN FOCI OF RESEARCH Aerosol Processes: Sources, Sinks, Transport, Components of Types, Relation of Size/Shape/Composition Direct /Indirect Radiative Forcing Effects on Remote Sensing Biosphere/ Atmosphere Interactions Health Hazards A - 12

13 CAS FOCUS ON AEROSOLS Publication of Recommendations for a Composite Surface- Based Aerosol Network, GAW Report No Provision of long-term sustained and consistent observations of aerosol properties through existing aerosol networks, complementing satellite and environmental agencies. Observational gaps and filling, standardization of measurement methods and data archiving protocols, improved data quality and an improved data delivery/data management system to multiple users, including researchers. To foster aerosol-related process studies, satellite validation, model development and validation, assimilation of observational data into operational models, and the creation of a comprehensive aerosol climatology on a global scale. To join networks like AERONET, SKYNET and MPLNET

14 CAS FOCUS ON AEROSOLS (Contd ) Measurements and reporting of PM2.5 and PM10 BC Measurements to continue, in collaboration with WHO and also by participation in the Climate and Clean Air Coalition (CCAC). Joint publication with UNEP of the Integrated Assessment of Black Carbon and Tropospheric Ozone and the publication by the Aerosol SAG on recommendations for reporting black carbon measurements in Atmos. Chem. Phys in 2013

15 GLOBAL TARGETS (PM 2.5) Spatial distributions of (a) mean annual PM2.5 concentration (μgm -3 ) and percentage of clear days per year with mean daily PM2.5 exceeding (b) 37.5 μgm -3 (WHO IT-3), (c) 50 μgm -3 (WHO IT-2) and (d) 75 μgm -3 (WHO IT-1) during Mar 2000 Feb 2010 over the Indian Subcontinent. Dey et al 2012

16 GLOBAL HOTSPOTS OF AEROSOLS Global distribution of MODIS aerosol optical depth at 0.55 μm showing aerosol hotspots for (a) MarchApril-May; (b) June-July-August; (c) SeptemberOctoberNovember; and (d) DecemberJanuary-February 2005

17 AEROSOL HOT SPOTS IN THE GLOBE MODIS AOD at 500 nm for September Kaufman et al., 2002, Nature

18 THE DESERT AEROSOL Global Phenomenon with Regional Implications. The Desert Aerosol Global Phenomenon with Regional Implications. Sub- Tropical Sources: Sahara and its Boundary Regions, ME, Saudi, Indian Deserts; South- African and Australian Deserts Middle & High Latitude Sources: Mongolia, Siberia, Gobi, Afghanistan

19 MEASURING AEROSOLS Remote Sensing Satellite (MODIS, MISR, TOMS, CALIPSO etc.) Aircraft Ground-based Radiometers instruments that quantify the amount of electromagnetic radiation (light). In-situ Aircraft Aerosol Spectrometer Samplers

20 GLOBAL MONITORING NETWORKS Remote sensing Satellites AERONET, SKYNET, GAW-PFR (Precision Filter Radiometers), German AOD network, SibRad (Siberia), PolarAOD, GALION: GAW Aerosol Lidar Observations Network, AD-Net (Asian Dust), LALINET (Latin America Lidar network), EARLINET (European Aerosol Research Lidar Network), MPLNET (Micro Pulse Lidar Network- Network for the Detection of Atmospheric Composition Change: NOAA) In-situ Observations: Light scattering, Light absorption, Number concentration, Mass concentration

21 AEROSOL MONITORING NETWORK (INDIA-SKYNET) 1. New Delhi 2. N. Delhi (1 Reference) 3. Ranichauri 4. Varanasi 5. Nagpur 6. Pune 7. Port Blair 8. Vizag 9. Guwahati 10. Kolkatta 11. Jodhpur 12. Rohtak 13. Trivandrum All these 12 locations will be equipped with Nephelometer, BC Monitors, Aerosol LIDAR and Chemical Characterization of Aerosols.

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23 18:30 23:30 09:30 14:30 19:30 00:30 05:30 15:30 20:30 01:30 11:30 16:30 21:30 07:30 12:30 17:30 22:30 03:30 13:30 EFFECT OF DUST STORM PM10 PM2.5 PM10 and PM2.5 increased drastically at Delhi with the arrival of duststorm Particulate Matter ( g/m 3 ) (a) Jodhpur (a) Delhi AOD 500 nm Mar, 19 Mar, 20 Mar, 21 Mar, 22 Mar, 23 (b) Jodhpur Angstrom Exponent Mar, 19 Mar, 20 Mar, 21 Mar, 22 Mar, (c) Jodhpur SSA at 500 nm AOD 500 nm Mar, 19 Mar, 20 Mar, 21 Mar, 22 Mar, 23 (b) Delhi Angstrom Exponent Mar, 19 Mar, 20 Mar, 21 Mar, 22 Mar, (c) Delhi SSA at 500 nm Mar, 19 Mar, 20 Mar, 21 Mar, 22 Mar, 23 Mar, 19 Mar, 20 Mar, 21 Mar, 22 Mar, 23 During the dust event, exceptionally high values of AOD and low values of Angstrom Exponent (close to 0) were noticed. SSA decreased during dust event Direct irradiance showed unusual and strong attenuation, reducing to 50.5 Wm -2 on March 20 as compared with Wm -2 on March 19 Variation of SW Direct Aerosol Radiative Forcing at Surface, TOA and Atmosphere during Dust Event at Jodhpur and Delhi

24 DIRECT AEROSOL RADIATIVE FORCING Minimum surface DARF and maximum atmosphere DARF are observed during summer season. Minimum surface DARF in June (approx. 100 Wm -2 ), Max atmosphere DARF in June (approx 70 Wm -2 )

25 AEROSOL BLACK CARBON Originates from the incomplete combustion of biomass or fossil fuel. It is produced only by combustion processes (natural or anthropogenic) and not by any known atmospheric reactions. Lifetime: of the order of days to weeks depending on the meteorology. Found from the Arctic to Antarctica. second most important contributor to global warming!

26 CARBONACEOUS AEROSOL soot elemental carbon formed in flames little spectral dependence carbon-only brown carbon : sugars alcohols aromatics di/tri acids ketoacids hydroxyacids

27 BLACK CARBON IMPLICATIONS Black carbon in the lower atmosphere are harmful air pollutants that have substantial regional and global climate impacts. They disturb tropical rainfall and regional circulation patterns such as the Asian monsoon, affecting the livelihoods of millions of people.

28 AEROSOL BLACK CARBON (Environmental impact) BC impact on the surface of snow and ice masses - reduces the surface albedo - increase melting - trigger albedo feedback - changes the glacier mass balance - contribute to glacier retreat

29 BLACK CARBON MEASUREMENT PROGRAMME Proposed IMD Stations Will start functioning in 2014

30 CHALLENGES Need to characterize aerosol mass/number concentration size distribution: ~10 nm to 10 m chemical composition: >hundreds compounds mixing state interactions with clouds Highly variable in space and time Regional and global aerosol forcing Large-scale Aerosol transport processes Aerosol solar dimming Possible aerosol microphysics effects on monsoon clouds and precipitation

31 AEROSOL MEASUREMENT Aerosol Optical Parameters (In Network) Multiwavelength Aerosol Optical Depth Single Scattering Albedo Phase Function / Asymmetry Parameter (Back /forward scat.) Aerosols size distribution, Spectrally dependent Refractive Index, Partition of spherical/non-spherical particles Vertical Distribution of Aerosols (LIDAR Observations) Light absorption coefficient / BC measurement Light scattering coefficient at various wavelengths Hemispheric backscattering coefficient at various wavelengths Radiative Forcing Other Continuous Aerosol Measurements (At Global Scale) Size resolved physical properties (Mass concentration, number concentration) and Cloud condensation nuclei at 0.5% supersaturation Intermittent Measurement Detailed size fractionated chemical composition of aerosols CCN spectra (various supersaturations) / Hygroscopic Growth

32 EFFECTIVE MONITORING PROGRAM Focused and relevant objectives. Appropriate design of monitoring network (Spatial Scale). Long-term commitment in terms of monitoring and assessment. High quality data collection and management. Careful analysis and interpretation of the result. Review, feedback and adaptation. Continually examine, interpret and present monitoring data.

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