Impacts of atmospheric aerosols and air pollution in Northern Eurasia and their dynamics

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1 Impacts of atmospheric aerosols and air pollution in Northern Eurasia and their dynamics Irina N. Sokolik School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta, GA, USA

2 Why Northern Eurasia? The world s largest sources of major aerosol types and air pollutants => strong regional and global signals (via long-range transport, teleconnection) Distinct trends in sources and spatial and temporal variability (due to region-specific climatic, economical and political changes) The regional nature of tropospheric aerosols

3 Climate radiative forcing of atmospheric aerosols can enhance or rival warming caused by GHGs Intergovernmental Panel on Climate Change (IPCC, 2007) Global mean radiative forcing (W/m2): 2005 relative to 1750 Direct radiative forcing by individual aerosol components (W/m2): Sulfates -0.4 (+/- 0.2) Nitrates -0.1 (+/-0.2) Fossil fuel OC (+/ ) Fossil fuel BC +0.2 (+/- 0.15) Biomass burning (+/-0.12) Dust -0.1 (+/-0.2) from -0.3 to +0.1 Complexity of tropospheric aerosols: different types (distinct sources, varying emissions, differing physical and chemical processes, fine and coarse size modes) short lifetime (up to a few weeks) heterogeneous distribution of sources and varying transport pathways aging (changes during transport) anthropogenic vs. natural aerosols light absorbing vs. light nonabsorbing aerosols many parameters are needed to characterize aerosols

4 Aerosols are hard to model AeroCom intercomparison of GCMs With some tuning, most GCMs can reproduce the global annual mead AOD Kinne et al. (2006)

5 Aerosols in Earth system models External and internal mixtures of main aerosol types Evolving size distribution and composition Max Planck Institute Earth System Model (MPI-ESM), Stier et al. (2006)

6 Global annual mean aerosol optical depth retrieved from MPI-ESM vs. AVHRR Max Planck Institute Earth System Model (MPI-ESM), Stier et al. (2006) Mishchenko et al.(2006) Over oceans only Only cloud-free sky AOD = natural + anthropogenic aerosols

7 Global dimming paradigm: aerosol-induced reduction in downward surface solar radiation Trend (%/10YR) Data of global (direct+diffuse) solar radiation from 160 FSU actinometric stations, ; Abakumova et al. (1996)!!!! Net effect of {Aerosols +clouds +H2O} + surface albedo

8 Solar dimming impact on soil moisture trends Robock and Li (2007): Aerosol induced-dimming controls soil moisture increases (cannot be explained by precipitation and T alone) Small effect of CO2 trends

9 Qian et al. (2003) Dimming and brightening in China

10 Regional to global linkages Sources of BC? Koch and Hansen (2005): Industrial and biofuel combustion in Southern Asia are a major source of BC in the Arctic Stohl (2006): Europe and northern Asia are the main sources Asian Dust ->Arctic Boreal Biomass burning -> Arctic Frequency and intensity?

11 Trends in aerosol optical depth in the Arctic Barrow, Alaska

12 Emissions of PM from stationary sources in 1988 (thousand tons) Data from Annual Bulletins on Air Pollution in the USSR cities and Industrial Centres, ; Shahgedanova and Burt (1994) Western Siberia Eastern Siberia Kazakhstan

13 Aerosols-energy-hydrological cycle linkages Direct and indirect radiative effect Effects on precipitation (via clouds) Deposition of light absorbing aerosols (soot and dust) on snow/ice (via snow/ice albedo feedback)

14 Dust effect on precipitation REFERENCE COMMENTS CONCLUSION Yin et al.(2002) Wurzler et al. (2000) Air parcel modeling dust promotes precipitation Rosenfeld et al. (2001) Case study of NOAA-AVHRR and TRMM data of Saharan dust Dust suppresses precipitation Rudich et al. (2002) Case study of NOAA-AVHRR data of Aral dust Aral dust promotes precipitation Miller et al.(2004) Modeling study using NASA GISS AGCM (resolution 4 0 x5 0 ), considered only surface radiative forcing mechanism, no dust-cloud interactions Dust promotes precipitation locally over desert regions Sokolik et al.

15 Climatology of Asian dust A combined effect of variability of met parameters and land cover/land use change Kurosaki et al. (2006)

16 Kurosaki and Sokolik Asian Dust Data Bank

17 Kurosaki and Sokolik Asian Dust Data Bank

18 Long-range transport of Asian dust from TOMS AI and MODIS AOD The perfect dust storm in 2001 MODIS AOD > 0.4 Apr 6 Apr 7 Apr 8 Apr 9 Apr 10 Apr 11 Apr 12 TOMS AI > 1.7 Apr 7 Apr 8,9 Apr 6 Apr 10 Apr 11 Apr 12 Darmenova et al.(2005)

19 Asian Dust Data Bank

20 Coupled regional modeling system Terrestrial preprocessor Adjustable water/land cover mask to reproduce different historical LULC scenarios in Central and East Asia; Data base of land properties for dust emission Mesoscale Model WRF (RegCM) Flexible nesting capability (down to 1 km) Driven by assimilated winds (NCEP or ECMWF) Radiative feedback Dust/cloud/precipitation coupling Dust Module DuMo Physically based-dust production schemes (coupled with the land model) Physically based-treatments of sizeresolved dust composition

21 Aerosol - ecosystem-hydrological cycle linkages Decrease surface SW radiation and increase LW radiation Aerosols Decrease SW direct radiation but may increase SW diffuse radiation => alter photosynthetically active radiation (PAR) ( nm) Positive or negative feedbacks? Other important processes: aerosol deposition on vegetation; aerosol impacts on O3 and rain acidity, etc.

22 Acid rain Forest area and growing stock at risk from sulfur and nitrogen depositions in Russia (Nilsson and Shvidenko, 1999) Forested area (in million ha) Sulfur Growing stock (in billion m 3 ) European Russia Asian Russia Total Nitrogen European Russia Asian Russia Total

23 Adverse impacts of aerosols on human well-being Health impact Particle size Fine aerosol particles are responsible for causing the greatest harm to human health. Inhaled deep into the lungs, they can cause breathing and respiratory problems, irritation, inflammation and cancer Agriculture impacts Aerosols cause decrease in solar radiation in the photosynthetically active region ( µm) reducing photosynthesis Reduction in productivity Deposition of particles on the plants shields solar radiation

24 NEESPI FRC AAAP Venue: School of Earth and Atmospheric Sciences (EAS) Georgia Institute of Technology, Atlanta, USA Leaders: Irina Sokolik, Robert Dickinson, Judith Curry Two-fold Objectives: Conduct, facilitate, and promote research aimed at improved understanding of interactions between changing aerosols, air pollutants and the Earth systems in Northern Eurasia Education and training

25 NEESPI FRC on Atmospheric Aerosol and Air Pollution 14 funded proposals relevant to aerosol/air pollution studies Science foci: Impact of wind-blown desert dust on ecosystem functioning, precipitation, and energy budget Climate, fires and emissions Impact of aerosols on hydrological cycle in the Arctic (IPY endorsed) Air quality and human health: Trans-Siberian observations (TROICA), POLLEN (allergic pollen in Europe) Many (???) NEESPI-related projects

26 The roles of aerosols in the Earth system Many challenges of do-it- all models Only TOA forcing is included in IPCC Impact on the radiative energy balance Impact on socioeconomic systems and human wellbeing Impact on clouds and precipitation Aerosol Impact on ecosystem functioning Impact on major biogeochemical cycles Impact on atmospheric composition and chemistry

27 Summary Climate change and population development in the 21th century are expected to cause increases in atmospheric aerosol concentrations. There is a clear need for improved knowledge of interactions between changing atmospheric aerosols and the Earth Systems to increase confidence in our understanding of how and why the climate and environment have changed and to develop improved predictive capabilities for integrated assessments of climate change in the future.

28 Focus of NEESPI Aerosol- and air pollution-induced interactions and feedbacks in the land biosphere-atmosphere system and their role in climate change What are the key aerosol- and air pollution-induced processes and feedbacks that have been affecting the energy, water and carbon fluxes over Northern Eurasia (their mechanisms, temporal and spatial scales)? How will the future changes in terrestrial ecosystem dynamics, climate and human factors affect the above processes in Northern Eurasia?