10 th Anniversary Systematic coordinated Saharan dust profiling over Europe in the frame of the EARLINET project (2000-2010) 2010) Alex PAPAYANNIS (Coordinator) and the EARLINET Team
Outline Role of aerosols in climate forcing EARLINET Network Correlative measurements- Validation tools Case study analysis (May 27-30, 2008) General results Conclusions
Role of aerosols in climatic forcing IPCC, 2007
Why dust aerosols are important Dust aerosols are produced in desert areas (e.g. Sahara desert) Dust aerosols interact dynamically in a nonlinear way (nucleation, condensation, coagulation, deposition) Dust aerosols can be transported over large distances (inter-continental transport) Systematic measurements m are needed to assess and improve the understanding of aerosol processes- transport-deposition and their treatment in models! Synergetic measurements are needed: - In situ measurements - Ground-based remote sensing (active/passive) measurements - Satellite (active/passive) measurements.
The EARLINET Network
Saharan dust outbreaks to Europe monitored by EARLINET Objectives Implementation of a routine monitoring scheme, for the observation on of specifically high aerosol loads in the lower troposphere, resulting from Saharan dust outbreaks. Methodology Perform correlative lidar-sun photometric supported by space-borne measurements (e.g. MODIS, CALIPSO, etc). Forecasting scheme Use dust forecasting models (BSC-DREAM8b, SKIRON) Coordination: National Technical Univ. of Athens (Warnings: 24-48 48 h)
Validation tools Air-mass back-trajectory analysis German Meteorological Service (DWD/GME Model) HYSPLIT Model, FLEXTRA/FLEXPART Models Satellite data analysis EP/TOMS & SeaWiFS data Sun photometer data analysis Aerosol Optical Depth (AOD) data Saharan dust events (2000-2010) 2010) > 3666 vertical profiles (extinction and backscatter profiles)
Definition of Saharan dust source regions 40 10 E 25 E -20-10 0 40 30 20 Arabian Peninsula 10 Western Sahara Foothills of Ahaggar and other mountains (Algeria, Mali, Niger) Central Sahara Bodele Depression (Lake Chad Basin) Eastern Sahara Foothills of the Red Sea Mountains (Sudan) Geographical lows and foothills, dry lakes and rivers mobilization of sediments of fine soil Prospero et al., 2002 Schepanski et al., 2007
Winter BSC-DREAM8b Model (2000-2009) 2009) Spring Summer Autumn
BSC-DREAM8b Model (2000-2009) 2009) Cross section over 33 o N, 10 o E 10 o E Winter 10 o E Spring 33 o N 33 o N Autumn Summer 10 o E 10 o E Autumn 33 o N 33 o N
BSC-DREAM8b Model (May 2000-April 2005) Potenza station 60 50 Lidar Dream Center of Mass (CoM) CoM Lidar = (4.5 ± 1.2) km CoM Dream = (4.4 ± 1.1) km 40 Aerosol Concentration [ µg m -3 ] 0 20 40 60 80 Counts 30 20 10 8 10 0 2 3 4 5 6 7 8 9 Layer Center of Mass a.s.l. [km] Altitude a.s.l. [km] 6 4 2 Aerosol concentration-aerosol extinction (355 nm) 0.0 5.0x10-5 1.0x10-4 1.5x10-4 Aerosol Extinction Coefficient @ 355 nm [m -1 ]
Seasonal variability of observed mean number of Saharan dust days (2000-2002) 40 Mean number of observed dust days 35 30 25 20 15 10 5 0 N NE Central W SW S SE Total Winter Spring Summer Fall Geographical sector Papayannis et al., J. Geophys. Res., 113, D10204, doi:10.1029/2007jd009028, 2008
240 Number of dust days 220 200 180 160 140 120 100 80 60 40 20 0 AT LCTHPONA BA LA SF JU NE GPMU PL LE BE ABHHMI KBLK EARLINET Station Observed Forecasted (%) of observed to forecasted number of days Papayannis et al., J. Geophys. Res., 113, D10204, doi:10.1029/2007jd009028, 2008
Number of dust profiles b aer,a aer (2000-2010) 600 500 400 300 200 100 0 TOTAL DJF-WINTER MAM-SPRING JJA-SUMMER SON-AUTUMN at ba bu ku la lc le mi na ne pa po so th EARLINET Station Name
0.6 100 90 Mean Aerosol Optical Depth 0.5 0.4 0.3 0.2 0.1 Mean Lidar Ratio (sr) 80 70 60 50 40 30 20 10 0.0 PO(1550) NA(1570) LA(1590) LC(1650) AT(1800) TH(1900) LE(2450) KB(2550) EARLINET Station 0 PO(1550) NA(1570) LA(1590) LC(1650) AT(1800) TH(1900) LE(2450) KB(2550) EARLINET Station Mean AOD and LR inside the dust layer (351/355 nm) as a function of distance from the Saharan region (2000-2002) Papayannis et al., J. Geophys. Res., 113, D10204, doi:10.1029/2007jd009028, 2008
7000 Raman nighttime measurements at 351/355nm Height a.s.l. (m) 6000 5000 4000 3000 2000 AT (15) KB (6) LA (27) LC (45) LE (11) NA (53) PO (38) TH (6) 1000 0 0.0 2.0x10-4 4.0x10-4 0.0 5.0x10-6 1.0x10-5 0 20 40 60 80 100 0 20 40 60 80 100 Extinction Coefficient (m -1 ) Backscatter Coefficient (m -1 sr -1 ) Lidar Ratio (sr) Lidar Ratio Standard Deviation (sr) Papayannis et al., J. Geophys. Res., 113, D10204, doi:10.1029/2007jd009028, 2008
Possible Pathways of Saharan Dust Transport over Europe 5 1 2 3 4 3 1: ~20 % 2: ~ 35 % 3: ~ 30 % 4: ~ 5 % 5: ~ 10 %
EARLINET Correlative Measurements CASE STUDY ANALYSIS: May 27-30, 2008 Saharan dust transport over Europe Synergy of various sensors + Validation tools: Active/Passive sensors: Lidar - CALIOP - SeaWiFS, CIMEL Dust Forecast Modeling: BSC-DREAM8b Air Mass Trajectory Computation: HYSPLIT 4.6 code FLEXTRA/FLEXPART
BSC-DREAM8b Model: Aerosol Optical Depth (AOD) @ 550 nm (Winds @ 3000 m) May 27, 2008 May 28, 2008 Athens Munich, Leipzig Sofia Potenza, Belsk May 29, 2008 May 30, 2008
Hysplit 4.6 Air Mass Trajectory Model Athens Leipzig Sofia Potenza May 27, 2008 May 28, 2008 May 29, 2008 May 30, 2008 SeaWiFS data
FLEXPART footprint (2000 m) Leipzig, 30 May 2008
FLEXPART footprint (2000 m) Potenza, 17 May 2008
FLEXPART footprint (2000 m) Potenza, 17 May 2008
FLEXPART footprint (2000 m) Belsk, 30 May 2008
FLEXTRA Air Mass Trajectory Model May 27, 2008 May 28, 2008 May 29, 2008 May 30, 2008 Athens (1.5,5 km) Leipzig (1.5,5 km) Sofia (3 km) Potenza (3 km) CIMEL AOD data
BSC-DREAM8b: Vertical cross-section across the CALIOP orbit Dust traces 5 May 27, 00:36-00:49 UT Athens EARLINETASOS-GALION Meeting, Geneva, 2020-23 September 2010 1064 nm
CALIOP 10 5 5 km 10 km 1064 nm Munich BSC-DREAM8b 10 km 7 5 km 5 May 28, 12:26-12:40 UT Leipzig
CALIOP Dust traces BSC-DREAM8b Sofia 3km 510 nm 3 km May 29, 11:31-11:44 UT
CALIOP 4 km 5-6 km 1-3 km 1064 nm Belsk BSC-DREAM8b Potenza 1064 nm May 30, 01:07-01:21 UT
Leipzig L Aquila Potenza Pappalardo et al., J. Geophys. Res., 115, D00H19, doi:10.1029/2009jd012147, 2010 Level 2 CALIOP data
Conclusions (dust event May 2008) We analyzed a strong dust event over the European continent (May 27-30, 2008) using a synergy of ground-based EARLINET lidars and CALIOP, as well as space-borne sensors and dust models (3-dimensional crosssection). The comparison between the BSC-DREAM8b 3-D profiles and the CALIOP & EARLINET aerosol vertical profiles shows a good (at least qualitative) agreement concerning the location in time and space - of the various dust layers detected.
Conclusions - Dust layer thickness (0.2-7.5 km); Mean value (1.5-3.4 km) - Dust layer center of mass (0.85-8 km asl.); Mean value (2.5-6 km) - Dust aerosols can penetrate deeply up to central, Eastern and Northern Europe (up to 8-10 km height asl., where may co-exist with clouds) - Transport time (typically 2-5 days) - Lidar ratios (ranges): 30-100 sr (including mixtures of dust with other particles) - Mean lidar ratios: 49±10 sr (355 nm), 56±7 sr (532 nm) -Mean AOD (0.1-0.25) inside the dust layer -TOMS Aerosol Index (AI) values: 3-3.5 (Mediterranean Region), 1-2.5 (Central Europe) - Maximum of dust outbreaks: South-South-Eastern Europe: * Summer, autumn and spring period (S-SE Europe) * Spring and summer (SW, central Europe)
Acknowledgements: All colleagues from the EARLINET TEAM (with Special thanks to Anja Hiebsch and Lucia Mona and Rodelize Mamouri). Prof. J.M. Baldasano and Dr. Sara Basart (BSC-DREAM8b model); NOAA-ARL (Hysplit code); Dr. Andreas Stohl (FLEXTRA data); AERONET (CIMEL data); SeaWIFS (NASA). This work was funded by the EU-FP5 (EARLINET project: EVR1- CT1999-40003), EU-FP6 ( project: RICA-025991] and the European Space Agency (ESA) under contract AO/1-5502/07/NL/HE.