European Aerosol Research Lidar Network: EARLINET Volker Matthias Max-Planck-Institut für Meteorologie, Bundesstraße 55, D-246 Hamburg, Germany
Contents. EARLINET Objectives 2. Quality Assurance 3. Station Statistics 4. Correlation Studies 5. Summary and Outlook
. Objectives of EARLINET EARLINET is a joint project of 22 lidar groups from different European countries 35 2 3 4 Main goals are to 6 6 establish a quantitative statistically relevant data base of the vertical aerosol distribution on a continental scale 5 5 provide a data base for further use in numerical models and for satellite validation 4 4 investigate aerosol transport and modification over Europe 3 35 2 3 4 3
EARLINET Lidar Systems Group Country elastic ch. Raman ch. Transportable 355 nm 532 nm 64 nm 355 nm MPI Hamburg D x x x x x MI Munich D x x x x U Aberystwyth GB x x NTU Athens GR x x x UPC Barcelona E x x x IFU Garmisch-P. D x x x x EPF Lausanne CH x x x x IAP Kühlungsborn D x x x x U L Aquila I x INFM Lecce I x IFT Leipzig D x x x x x IST Lisbon P x x x FOA Linköping S x x IPNANB Minsk BY x x INFM Napoli I x OC Neuchâtel CH x x x x LMD Palaiseau F x x INFM Potenza I x x x AU Thessaloniki GR x x x : emitted wavelength is 35 nm : emitted wavelength is 353 nm.
Aerosol Profiles 6 98/9/7 8:28 8:4 UT aerosol extinction [/m]..2.3.4.5 backscatter extinction 6 98/9/7 8:28 8:4 UT lidar ratio [sr] 2 4 6 8 2 lidar ratio 5 5 4 4 altitude [m asl] 3 altitude [m asl] 3 2 2 2e 6 4e 6 6e 6 8e 6 e 5 aerosol backscatter [/(m*sr)] 2 4 6 8 2 lidar ratio [sr]
EARLINET Data Base Files are stored in NetCDF format More than 3 profiles have been collected since May, 2 Lists lead to files that address special topics, e.g. Saharan dust: 985 profiles Diurnal cycles: 65 profiles Forest fires: 74 profiles Etna eruption: 8 profiles Data base is not public, but data can be used upon request (see http://lidarb.dkrz.de/earlinet or send email to boesenberg@dkrz.de)
2. Quality Assurance For joint sudies and comparative statistics using network measurements, quality assurance (QA) is of very high importance MIM IMAA INFM(L) IFT (mob.) IFT (stat.) MPI MPI (3λ) UABER EARLINET QA procedure : quality criteria were predefined INFM(N) ULAQ EPFL FOA OCN(mob.) standard systems have been compared to new systems AUTH OCN (stat.) UPC quality controlled systems could serve as standard systems themselves NTUA IFU IAP LMD(mob.) IST LMD
System Intercomparisons: Aerosol Backscatter Lidar intercomparisons: MIM/INFM(N) 2//3, 4:2 4:26 and 2//6, 8:2 8:3 7 6 5 MIM 355 nm, 2//3 INFM(N) 35 nm, 2//3 MIM 355 nm, 2//6 INFM(N) 35 nm, 2//6 958 Lidar intercomparisons: OCN/EPFL 2/5/7, 532 nm OCN (Micro), 23: 23:29 UT EPFL, 23: 23:29 UT altitude [m asl] 4 3 altitude [m asl] 758 2 558 2 6 4 6 6 6 8 6 358 2 6 4 6 6 6 8 6 aerosol backscatter [/(m sr)] aerosol backscatter [/(m sr)]
Aerosol Backscatter: Deviations in the Dust Layer Mean deviations within the atmospheric dust layer of all performed intercomparisons mean deviation [%] 4 2-2 355 nm 532 nm 64 nm -4 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 Lidar group standard deviation [%] 5 45 4 35 3 25 2 5 5 Standard deviations within the atmospheric dust layer of all performed intercomparisons 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 Lidar group 355 nm 532 nm 64 nm
Aerosol Backscatter: Deviations in the Free Troposphere mean deviation [ 7 (m sr) ] 5 5 Mean deviations in the free troposphere of all performed intercomparisons 355 nm 532 nm 64 nm 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 Lidar group standard deviation [ 7 (m sr) ] 8 6 4 2 Standard deviations in the free troposphere of all performed intercomparisons 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 Lidar group 355 nm 532 nm 64 nm
Backscatter Algorithm Intercomparisons: Case 2, Stage 3
3. Station Statistics 3 25 PBL height in Hamburg (997/2/ 22/9/3) 7 days gliding average measurements sinus fit PBL height [m asl] 2 5 5 4 8 2 6 2 24 28 32 36 4 44 48 52
Aerosol optical depth in PBL in Hamburg mean AOD.26.22 (355 nm), skewness.84.8.7 Aerosol optical depth in the PBL in Hamburg (997/2/ 22/2/28) 42 days gliding average measurements.6.5.4.3.2. 4 8 2 6 2 24 28 32 36 4 44 48 52
Cumulative frequency distribution of the AOD in the PBL in Hamburg AOD in the PBL, Hamburg, 997/2/ - 22/9/3.9.8 Cumulative frequency.7.6.5.4.3.2. Measurements, median =.25 Lognormal distribution, m = -.63 (OD =.96), s =.765..2.3.4.5.6.7.8.9 AOD
Comparison of the annual cycle of the AOD in the PBL () Aberystwyth (5/2 /22): AOD =.6 ±.3 Hamburg (5/2 9/22): AOD =.26 ±.2.8.6.4.2 7 days gliding average optical depth.8.6.4.2 7 days gliding average optical depth 4 8 2 6 2 24 28 32 36 4 44 48 52 4 8 2 6 2 24 28 32 36 4 44 48 52 Kühlungsborn (5/2 9/22): AOD =.5 ±.9 Leipzig (5/2 7/22): AOD =.29 ±.22.8.6.4.2 7 days gliding average optical depth.8.6.4.2 7 days gliding average optical depth 4 8 2 6 2 24 28 32 36 4 44 48 52 4 8 2 6 2 24 28 32 36 4 44 48 52
Comparison of the annual cycle of the AOD in the PBL (2) L Aquila (5/2 9/22): AOD =.3 ±.3 Lecce (5/2 8/22): AOD =.25 ±.3.8.6.4.2 7 days gliding average optical depth.8.6.4.2 7 days gliding average optical depth 4 8 2 6 2 24 28 32 36 4 44 48 52 4 8 2 6 2 24 28 32 36 4 44 48 52 Naples (/2 /22): AOD =.25 ±.5 Potenza (5/2 9/22): AOD =.23 ±..8.6.4.2 7 days gliding average optical depth.8.6.4.2 7 days gliding average optical depth 4 8 2 6 2 24 28 32 36 4 44 48 52 4 8 2 6 2 24 28 32 36 4 44 48 52
Comparison of the annual cycle of the AOD in the PBL (3) Athens (/2 8/22): AOD =.3 ±.3 Thessaloniki (2/2 8/22): AOD =.27 ±.9.8.6.4.2 7 days gliding average optical depth.8.6.4.2 7 days gliding average optical depth 4 8 2 6 2 24 28 32 36 4 44 48 52 4 8 2 6 2 24 28 32 36 4 44 48 52
Vertical distribution of the aerosol extinction.6 Vertical distribution of the mean aerosol extinction at 355 nm: May 2 Nov 22 Layers km (red), 2 km (green) and 2 5 km (blue).5 aerosol extinction [/km].4.3.2. ab hh kb le la lc na po at th Lidar station
Comparison of aerosol backscatter profiles (532 nm) (Seasonal averages) 4 35 Mean aerosol backscatter profile at 532 nm. October March (winter) and April September (summer) Belsk, winter Belsk, summer 4 35 Mean aerosol backscatter profile at 532 nm. October March (winter) and April September (summer) Hamburg, winter Hamburg, summer 3 3 altitude / m 25 2 5 altitude / m 25 2 5 5 5 2e 6 4e 6 6e 6 8e 6 e 5 aerosol backscatter / /(m sr) 2e 6 4e 6 6e 6 8e 6 e 5 aerosol backscatter / /(m sr) 4 35 Mean aerosol backscatter profile at 532 nm. October March (winter) and April September (summer) Leipzig, winter Leipzig, summer 4 35 Mean aerosol backscatter profile at 532 nm. October March (winter) and April September (summer) Minsk, winter Minsk, summer 3 3 altitude / m 25 2 5 altitude / m 25 2 5 5 5 2e 6 4e 6 6e 6 8e 6 e 5 aerosol backscatter / /(m sr) 2e 6 4e 6 6e 6 8e 6 e 5 aerosol backscatter / /(m sr)
4. Correlation Studies Comparison of Hamburg-City and Hamburg-Bergedorf Data Date IB City IB Bergedorf Trajectory 9 UT [ sr ] sr ].2 Integrated backscatter (IB) Hamburg City/Bergedorf correlation coeff..96 % deviation /2/3.22 2.3 SE 2//3.34.4 SE 2/2/4.52.7 E 2/2/2.63.67 NW 2/3/28 3.58 4.3 SE 2/4/4 2.87 3.29 E 2/6/3.99 2.57 SE 2/8/5.9 5.33 N 2/8/9.99.8 SE 2/8/29 8.5 9.9 NW (95hPa) SW (85hPa) 2/9/2 2.9 2.86 E 2/9/2.58 2.53 E 2/9/3.74.4 SW 2//5 3.23 3.3 SE mean 3.62 4.22 IB Hamburg Bergedorf / /sr..8.6.4.2.2.4.6.8..2 IB Hamburg City / /sr
Correlation of AOD at different sites Assumptions: Only common days and common height ranges have been taken integrated aerosol backscatter / /sr.2..8.6.4.2 Hamburg centre / Bergedorf: correlation coeff..96 Hamburg centre Bergedorf 7/ / / 4/ 7/ / /2 4/2 7/2 /2 date.8.6.4.2 Hamburg/Kühlungsborn: correlation coefficient.78 Hamburg Kühlungsborn 7/ / / 4/ 7/ / /2 4/2 7/2 /2 date.8.6.4.2 Hamburg/Leipzig: correlation coefficient.3 Hamburg Leipzig.8.6.4.2 Hamburg/Napoli: correlation coefficient.36 Hamburg Napoli 7/ / / 4/ 7/ / /2 4/2 7/2 /2 date 7/ / / 4/ 7/ / /2 4/2 7/2 /2 date
5. Summary and Outlook EARLINET provides vertical profiles of aerosol extinction and backscatter on a regular basis EARLINET data has passed QA for instruments and algorithms Statistical evaluations show: PBL-height and AOD show large variability at all stations AOD in the PBL follows a lognormal distribution Vertical distribution shows main diiferences at higher altitudes High correlation of AOD for distances of a few tens of km have been found Measurements are continued at several stations after the end of the project New funds are necessary to maintain the regular operation of the EARLINET stations Acknowledgements EARLINET has been funded by European Commission under grant no. EVR-CT-999-43