1. AN IMPORTANT FINGERPRINT OF WILDFIRES ON THE EUROPEAN AEROSOL LOAD Francesca Barnaba, Federico Angelini, Gabriele Curci, Gian Paolo Gobbi CNR - Area Ricerca Tor Vergata 12 January 2010 CNR - Area Ricerca Tor Vergata 14 January 2010 ISAC-CNR, Rome, Italy f.barnaba@isac.cnr.it CETEMPS - Dip. Fisica Università dell’Aquila, Italy gabriele.curci@aquila.infn.it [Barnaba et al., ACPD 2011] EGU 2011, 4 April, Vienna

2. … but a “bimodal” cycle is observed AOT Data Counts AOT anomaly AEROSOL OPTICAL THICKNESS (AOT) IN ROME DOES NOT PERFECTLY FOLLOW A “SINUSOIDAL” YEARLY CYCLE … http://aeronet.gsfc.nasa.gov/ ROME [Yu et al., JGR 2003 ] AOT is expected to have a “sinusoidal” yearly cycle

3. AOT “BIMODALITY” IS A MORE GENERAL FEATURE OVER EUROPE AOT and FFAOT @ 550 nm from MISR satellite instrument also shows significant deviation from “sinusoidal” yearly cycle. AOT max: April & Jul-Aug 2002-2007 average

4. WILDFIRES IN EASTERN EUROPE ARE MOSTLY CONCENTRATED IN EARLY SPRING & SUMMER Example: MODIS Fire Counts 2006 Spring Summer These fires are mostly related to human activities (crops, forestry, …)

5. WE COMBINE SATELLITE DATA AND TRAJECTORY MODEL TO ESTIMATE THE IMPACT OF WILDFIRES ON EUROPEAN AOT 1.MISR AOT & Fine Fraction AOT (< 0.35 µm), λ = 550 nm, 0.5° x 0.5° Level 3 Monthly 2.MODIS, 0.5° x 0.5° Level 3 Monthly mean: –Fire Counts, FC (counts/km 2 /day) –Fire Radiative Power, FRP (MW) 3.HYSPLIT Lagrangian trajectory model (http://ready.arl.noaa.gov) q n1 T n1 n2 T n2 FRP n2 FRP n1 Target Region Combining 2 and 3 we derive a Fire Weighted Trajectory Density (FWTD) 5 days

6. MONTHLY FIRE WEIGHTED TRAJECTORY DENSITY (FWTD) 2002-2007 JANFEBMARAPR MAYJUNJULAUG SEPOCTNOVDEC

7. FWTD YEARLY CYCLE IN PHASE WITH AOT & FFAOT MISR AOT 2002-2007 average MISR FFAOT (~ no dust/sea salt) FWTD LARGER INTER-ANNUAL VARIABILITY @ MAX

8. IMPACT OF EASTERN EUROPE FIRES IS UBIQUITOUS. PORTUGAL FIRES LIMITED TO SOUTH-WESTERN EUROPE Q1 Q2 Q3 Q4 Eastern Europe (Q3) Fires WMed (Q1) Fires

9. CONTRIBUTION OF WILDFIRES TO FINE FRACTION AOT (FFAOT): ESTIMATED FROM DIFFERENCE WITH “SINUSOIDAL” FIT OBSERVED MISR FFAOT FFAOT_RB (fit) FFAOT_WF = FFAOT – FFAOT_RB “Reconstructed” FFAOT

10. CONTAMINATION FROM INTERCONTINENTAL TRANSPORT FROM NORTH AMERICA SIGNIFICANT ONLY IN SOUTH-WESTERN EUROPE IN SPRING MISR FFAOT JULY 2002-2007 average MISR FFAOT FFAOT_RB (fit) FFAOT – FFAOT_RB

11. CONCLUDING REMARKS A step forward toward a comprehensive long-term (2002-2007) evaluation of wildfires impact (mostly from agricultural & forestry practices) on European aerosol load: previous studies focused on episodic events. A combination of satellite observations and trajectory modelling show that fires (mostly from Eastern EU and European Russia) contribute to a continent-wide haze. In spring and summer, 10-30% of Fine Fraction AOT over Europe is related to wildfires. Clear target for mitigation: biomass energy production and air quality To be done: Evaluation of the impact on PM at the ground (air quality) – Preliminary estimate on PM10: WF Fine Fraction AOT = 0.04 Mass-to-extinction = 4 m 2 /g Column Mass = 0.01 g/m 2 If PBL Height = 1000 m and Uniform distribution Monthly mean WF related PM10 = 10 µg/m 3