1. Biogenic Sulfate in the Arctic and its Contribution to Aerosol Growth and IN Activation A.L. Norman NETCARE Meeting Nov. 19, 2013 Atmospheric & Environmental Physics The University of Calgary

2. Atmospheric & Environmental Physics Group A.L. Norman O. Rempillo (PDF) M. A. Seguin (PDF) N. Pak (MSc) C. Teng (BSc) J. Roberts (BSc) & R. Ghahremaninenez- hadgeharelar (PhD) M. Alam (PhD) V. Wasiuta (PhD) P.S. Stainton (MSc)

3. Sulfur Isotope Apportionment aerosols - largest uncertainty in climate prediction clouds & precipitation - link weather & climate Research Questions: biogenic sulfate: -what role does it play in aerosol growth? -is it important to IN activation? BIOGENIC ANTHROPOGENIC SEA SALT

4. DMS Methane Sulfonic Acid SO 4 2- New Aerosol Addition Abstraction SO 2 Low Albedo Clouds High Albedo Clouds Aerosol Growth

5. DMS Methane Sulfonic Acid SO 4 2- New Aerosol Addition Abstraction SO 2 Cascade Impactor High Volume Sampler Aerosol Growth DMS Sampler

6.  34 S (‰) = [( 34 S/ 32 S) x / ( 34 S/ 32 S) VCDT - 1] ISOTOPE SOURCE APPORTIONMENT Sea Salt Sulfate DMS Volcanic Degassing Methanesulfonic Acid (MSA) Anthropogenic S Aerosol S Isotope Variations in the Arctic -20 -10 0 +10 +20  34 S (% o ) Smoking Hills

7.  34 S ( ‰ )

8. Alert Aerosols: Winter (JFM) non sea salt  34 S

9. Trends in Anthropogenic & Biogenic Sulfate at Alert Year Satellite Observations

11. Effective Ice Radius (  m) Antrhropogenic Sulphate (ng/m 3 ) Cloud Fraction Increases when anthropogenic sulphate is lower More deposition at high concentration? Effective Ice Radius Increases as anthro- pogenic sulphate Increases Consistent with Growth of ice nuclei Spring & Summer

12. NSS sulphate contributes to growth but does biogenic sulphate ACTIVATE ice nuclei?

13. Objectives for Netcare Understand the decoupling of MSA and biogenic sulfate aerosols in late May early June using size segregated aerosol sampling. Use isotope apportionment to quantify anthropogenic, biogenic and sea salt sulfate in precipitation and ice fog. These data will inform models of aerosol growth

14. ACKNOWLEDGEMENTS CCAR EC

15. Questions? Photo: V. Wasiuta

16. MODIS Satellite Data: Go-Cart Sulphate Optical Depth >70 o N

17. … but decreases with cloud fraction In summer (maybe) Biogenic Sulphate increases with cloud fraction in spring Contributes to CCN? In 2001 when the proportion of biogenic sulphate is maximum