Characterization of free-tropospheric aerosol layers from different source regions

Transcription

1 Leibniz Institute for Tropospheric Research Leipzig, Germany Characterization of free-tropospheric aerosol layers from different source regions Ina Mattis, Detlef Müller, Albert Ansmann, Ulla Wandinger, and Dietrich Althausen The 7th International Symposium on Tropospheric Profiling: Needs and Technologies (ISTP), Boulder, Colorado, USA, June 11-17, 2006.

2 Characterization of free-tropospheric aerosol layers from different source regions The 7th International Symposium on Tropospheric Profiling: Needs and Technologies (ISTP), Boulder, USA, June Aerosols in the free troposphere Which observations were used? Long-range transport in the free troposphere: - Frequency of occurence - Geometrical properties of the layers - Optical aerosol properties - Microphysical aerosol properties Summary

3 Aerosols in the free troposphere comparably long life time transport over long distances

4 Aerosols in the free troposphere comparably long life time transport over long distances Satellite observation of forest fires near Lake Baykal, Siberia, 19 May 2003

5 Aerosols in the free troposphere Tracer transport simulations show hemispheric dispersion

6 Aerosols in the free troposphere Leipzig, Germany: BACKSCATTER RATIO at 1064 nm BSC.COEF. at 532nm Mm -1 sr May 2003 HEIGHT, km TIME AFTER START OF MEASUREMENT, min Background from EARLINET May-July

7 Aerosols in the free troposphere comparably long life time transport over long distances often observed significant contribution to total optical depth FT layers are masked by underlaying PBL aerosols difficult to characterize with passive remote-sensing instruments vertically resolved, multi-wavelengths Raman lidar measurements The 7th International Symposium on Tropospheric Profiling: Needs and Technologies (ISTP), Boulder, USA, June 2006.

8 Aerosols in the free troposphere Saharan dust over Leipzig, October 13, 2001

9 Stationary IfT Raman lidar Observations German lidar network: Leipzig European Aerosol Research Lidar Network (EARLINET): Leipzig Anthropogenic pollution from North America Anthropogenic pollution from Europe Aged anthropogenic pollution from polar regions Forest-fire smoke from North America Forest-fire smoke from Siberia Mineral dust from Africa European pollution in the PBL long-range transport in the free troposphere

10 Observations Transportable IfT multi-wavelength Raman lidar Aerosol Characterization Experiment 2 (ACE 2): southwest coast of Portugal 1997 Anthropogenic pollution from Europe long-range transport in the free troposphere Marine particles in the PBL (clean and polluted)

11 Observations Transportable IfT multi-wavelength Raman lidar Aerosol Characterization Experiment 2 (ACE 2): southwest coast of Portugal 1997 Lindenberg Aerosol Characterization Experiment (LACE): Lindenberg, near Berlin 1998 Anthropogenic pollution from Europe Forest-fire smoke from North America long-range transport in the free troposphere Marine particles in the PBL (clean and polluted)

12 Observations Transportable IfT multi-wavelength Raman lidar Aerosol Characterization Experiment 2 (ACE 2): southwest coast of Portugal 1997 Lindenberg Aerosol Characterization Experiment (LACE): Lindenberg, near Berlin 1998 Indian Ocean Experiment (INDOEX): Maldives, Anthropogenic pollution from Europe Anthropogenic pollution from India Anthropogenic pollution from South East Asia Forest-fire smoke from North America Dust from Arabia Marine particles in the PBL (clean and polluted) long-range transport in the free troposphere

13 Products Profiles of optical aerosol properties Backscatter coefficient at 355, 532, 1064 (400, 710, 800) nm Extinction coefficient at 355, 532 nm Ångström exponent Lidar ratio at 355, 532 nm Depolarization ratio Profiles of microphysical aerosol properties from Inversion Effective radius Volume and surface-area concentration Complex refractive index Single-scattering albedo without any a priori assumptions on aerosol type

14 Frequency distributions 640 regular EARLINET measurements at Leipzig between 1997 and 2004 Free-tropospheric layers in about 45% of the regular measurements.

15 Geometrical layer properties from 640 regular measurements over Leipzig ( ) The bottom of the lowermost free-tropospheric layer is at or above 2-km height in approximately 45% of all cases. The top height and geometrical depth are higher for Saharan dust than for pollution from NA.

16 Optical depth PBL lofted layers

17 Comparison to AERONET Sun Photometer Biomass Burning Urban / Industrial Southeast Asia Oceanic Dust (spheres) Dust (spheroids) Raman Lidar Forest-Fire Smoke Forest-Fire Smoke (Leipzig) (Spitsbergen) Urban/Industrial Urban/Industrial (N.America; Leipzig) (Europe; ACE 2) Southeast Asia South China (INOEX) (PRD) Dust Dust (Sahara) (INDOEX) Oceanic Oceanic (ACE 2) (INDOEX) The Sun photometer results have been reproduced from Fig. 8 of Cattrall et al. [2005]. We kindly thank Christoph Ritter (AWI Potsdam, Germany) for providing the multiwavelength Raman lidar measurements from Spitsbergen. The 7th International Symposium on Tropospheric Profiling: Needs and Technologies (ISTP), Boulder, USA, June 2006.

18 Characteristic optical signatures source å S532 S355 / S532 clean marine PBL 0.1 < 35 sr 1 North India sr > 1 South India sr > 1 SE Asia sr > 1 anthr. pollution from Europe sr > 1 European PBL sr > 1 anthr. pollution from NA sr > 1 anthr. pollution from north of 70 N sr > 1 forest-fire smoke from NA and Siberia sr < 1 Sahara sr > 1

19 Microphysical aerosol properties Anthropogenic Forest-fire Marine Anthr./Biomass

20 Summary Aerosols in the free troposphere (640 measurements at Leipzig) - observed in 45% of all cases - 20% of total optical depth Multiwavelength Raman lidar observations (3b+2a) Vertically resolved measurements Optical and microphysical aerosol properties without assumptions on aerosol type Characterization and identification of different aerosol types Global network of advanced Raman lidars provide improved aerosol models for satellite retrievals and global modeling provide lidar-ratio input for CALIPSO retrievals

21 Leipzig, July 22, 2004: Time series Range corrected signal at 1064 nm

22 Leipzig, July 22, 2004: Tracer FLEXTRA tracer transport simulation Lidar observation free tropospheric layers dust layer

23 Leipzig, July 22, 2004: Optical data

24 Leipzig, July 22, 2004: Microphysical data Layer mean values OD OD Å 0.9 S sr S sr reff 0.23 µm ssa 0.89