Potential of polarization/Raman lidar to separate fine dust, coarse dust, maritime, and anthropogenic aerosol profiles

Abstract. We applied the recently introduced Polarization Lidar Photometer Networking (POLIPHON) technique for the first time to triple-wavelength polarization lidar measurements at 355, 532, and 1064 nm. The lidar observations were performed at Barbados during the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) in the summer of 2014. POLIPHON comprises the traditional lidar technique to separate mineral dust and non-dust backscatter contributions and the new extended approach to separate even the dust backscatter component into fine and coarse dust fractions. We show that the traditional and the extended methods are compatible and lead to the same set of dust and non-dust profiles at simplified, less complex aerosol layering and mixing conditions as is the case over the remote tropical Atlantic. To derive dust mass concentration profiles from the lidar observations, trustworthy extinction-to-volume conversion factors are needed and obtained from an updated, extended AERONET sun photometer data analysis of the correlation of fine, coarse and total dust volume concentration with dust extinction coefficients for all three laser wavelengths. Conversion factors for pure marine aerosol conditions and continental anthropogenic aerosol situations are presented in addition. As an additional new feature of POLIPHON, the Raman-lidar method for particle extinction profiling is used to identify the aerosol type (marine or anthropogenic) of the non-dust aerosol fraction. The full POLIPHON methodology was successfully applied to a SALTRACE case and the results are discussed. We conclude that the 532 nm polarization lidar technique has many advantages in comparison to respective 355 and 1064 nm polarization lidar approaches and leads to most robust and accurate POLIPHON products.

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Potential of polarization/Raman lidar to separate fine dust, coarse dust, maritime, and anthropogenic aerosol profiles

Atmospheric Measurement Techniques ◽

10.5194/amt-10-3403-2017 ◽

2017 ◽

Vol 10 (9) ◽

pp. 3403-3427 ◽

Cited By ~ 36

Author(s):

Rodanthi-Elisavet Mamouri ◽

Albert Ansmann

Keyword(s):

Data Analysis ◽

Raman Lidar ◽

Anthropogenic Aerosol ◽

Conversion Factors ◽

Total Dust ◽

Lidar Measurements ◽

Range Transport ◽

Aerosol Fraction ◽

New Feature ◽

Lidar Observations

Abstract. We applied the recently introduced polarization lidar–photometer networking (POLIPHON) technique for the first time to triple-wavelength polarization lidar measurements at 355, 532, and 1064 nm. The lidar observations were performed at Barbados during the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) in the summer of 2014. The POLIPHON method comprises the traditional lidar technique to separate mineral dust and non-dust backscatter contributions and the new, extended approach to separate even the fine and coarse dust backscatter fractions. We show that the traditional and the advanced method are compatible and lead to a consistent set of dust and non-dust profiles at simplified, less complex aerosol layering and mixing conditions as is the case over the remote tropical Atlantic. To derive dust mass concentration profiles from the lidar observations, trustworthy extinction-to-volume conversion factors for fine, coarse, and total dust are needed and obtained from an updated, extended Aerosol Robotic Network sun photometer data analysis of the correlation between the fine, coarse and total dust volume concentration and the respective fine, coarse, and total dust extinction coefficient for all three laser wavelengths. Conversion factors (total volume to extinction) for pure marine aerosol conditions and continental anthropogenic aerosol situations are presented in addition. As a new feature of the POLIPHON data analysis, the Raman lidar method for particle extinction profiling is used to identify the aerosol type (marine or anthropogenic) of the non-dust aerosol fraction. The full POLIPHON methodology was successfully applied to a SALTRACE case and the results are discussed. We conclude that the 532 nm polarization lidar technique has many advantages in comparison to 355 and 1064 nm polarization lidar approaches and leads to the most robust and accurate POLIPHON products.

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Profiling of Saharan dust from the Caribbean to western Africa – Part 1: Layering structures and optical properties from shipborne polarization/Raman lidar observations

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-12963-2017 ◽

2017 ◽

Vol 17 (21) ◽

pp. 12963-12983 ◽

Cited By ~ 18

Author(s):

Franziska Rittmeister ◽

Albert Ansmann ◽

Ronny Engelmann ◽

Annett Skupin ◽

Holger Baars ◽

...

Keyword(s):

Optical Properties ◽

Conceptual Model ◽

Long Range Transport ◽

Tropical Atlantic ◽

Raman Lidar ◽

Western Africa ◽

Range Transport ◽

Lidar Ratio ◽

The Caribbean ◽

Lidar Observations

Abstract. We present final and quality-assured results of multiwavelength polarization/Raman lidar observations of the Saharan air layer (SAL) over the tropical Atlantic. Observations were performed aboard the German research vessel R/V Meteor during the 1-month transatlantic cruise from Guadeloupe to Cabo Verde over 4500 km from 61.5 to 20° W at 14–15° N in April–May 2013. First results of the shipborne lidar measurements, conducted in the framework of SALTRACE (Saharan Aerosol Long-range Transport and Aerosol–Cloud Interaction Experiment), were reported by Kanitz et al.(2014). Here, we present four observational cases representing key stages of the SAL evolution between Africa and the Caribbean in detail in terms of layering structures and optical properties of the mixture of predominantly dust and aged smoke in the SAL. We discuss to what extent the lidar results confirm the validity of the SAL conceptual model which describes the dust long-range transport and removal processes over the tropical Atlantic. Our observations of a clean marine aerosol layer (MAL, layer from the surface to the SAL base) confirm the conceptual model and suggest that the removal of dust from the MAL, below the SAL, is very efficient. However, the removal of dust from the SAL assumed in the conceptual model to be caused by gravitational settling in combination with large-scale subsidence is weaker than expected. To explain the observed homogenous (height-independent) dust optical properties from the SAL base to the SAL top, from the African coast to the Caribbean, we have to assume that the particle sedimentation strength is reduced and dust vertical mixing and upward transport mechanisms must be active in the SAL. Based on lidar observations on 20 nights at different longitudes in May 2013, we found, on average, MAL and SAL layer mean values (at 532 nm) of the extinction-to-backscatter ratio (lidar ratio) of 17±5 sr (MAL) and 43±8 sr (SAL), of the particle linear depolarization ratio of 0.025±0.015 (MAL) and 0.19±0.09 (SAL), and of the particle extinction coefficient of 67±45 Mm−1 (MAL) and 68±37 Mm−1 (SAL). The 532 nm optical depth of the lofted SAL was found to be, on average, 0.15±0.13 during the ship cruise. The comparably low values of the SAL mean lidar ratio and depolarization ratio (compared to typical pure dust values of 50–60 sr and 0.3, respectively) in combination with backward trajectories indicate a smoke contribution to light extinction of the order of 20 % during May 2013, at the end of the burning season in central-western Africa.

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Multiwavelength Raman lidar observations of particle growth during long-range transport of forest-fire smoke in the free troposphere

Geophysical Research Letters ◽

10.1029/2006gl027936 ◽

2007 ◽

Vol 34 (5) ◽

Cited By ~ 60

Author(s):

D. Müller ◽

I. Mattis ◽

A. Ansmann ◽

U. Wandinger ◽

C. Ritter ◽

...

Keyword(s):

Long Range ◽

Forest Fire ◽

Particle Growth ◽

Long Range Transport ◽

Free Troposphere ◽

Raman Lidar ◽

Fire Smoke ◽

Range Transport ◽

Lidar Observations

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Vertical aerosol distribution in the Southern hemispheric Midlatitudes as observed with lidar at Punta Arenas, Chile (53.2° S and 70.9° W) during ALPACA

10.5194/acp-2018-1124 ◽

2018 ◽

Author(s):

Andreas Foth ◽

Thomas Kanitz ◽

Ronny Engelmann ◽

Holger Baars ◽

Martin Radenz ◽

...

Keyword(s):

Long Range Transport ◽

Free Troposphere ◽

Marine Aerosol ◽

Raman Lidar ◽

Aerosol Distribution ◽

Range Transport ◽

Aerosol Sources ◽

Ground Based Lidar ◽

Lidar Observations ◽

Measurement Period

Abstract. Within this publication, lidar observations of the vertical aerosol distribution above Punta Arenas, Chile (53.2° S and 50.9° W) which have been performed with the Raman lidar PollyXT from December 2009 to April 2010 are presented. Pristine marine aerosol conditions related to the prevailing westerly circulation dominated the measurements. Lofted aerosol layers could only be observed eight times during the whole measurement period. Two case studies are presented showing long-range transport of smoke from biomass burning in Australia and regionally transported dust from the Patagonian Desert, respectively. The aerosol sources are identified by trajectory analyses with HYSPLIT and FLEXPART. However, seven of the eight analysed cases with lofted layers show an aerosol optical thickness of less than 0.05. From the lidar observations a mean planetary boundary layer (PBL) top height of 1150 ± 350 m was determined. An analysis of particle backscatter coefficients confirms that the majority of the aerosol is attributed to the PBL while the free troposphere is characterized by a very low background aerosol concentration. The ground-based lidar observations at 532 and 1064 nm are supplemented by the AERONET Sun photometers and the space-borne lidar CALIOP on board of CALIPSO. The averaged AOT determined by CALIOP was 0.02 ± 0.01 at Punta Arenas from 2009 to 2010.

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From the Caribbean to West Africa: Four weeks of continuous dust and marine aerosol profiling with shipborne polarization/Raman lidar – a contribution to SALTRACE

10.5194/acp-2017-130 ◽

2017 ◽

Cited By ~ 3

Author(s):

Franziska Rittmeister ◽

Albert Ansmann ◽

Ronny Engelmann ◽

Annett Skupin ◽

Holger Baars ◽

...

Keyword(s):

Long Range ◽

Prediction Models ◽

Saharan Dust ◽

Dust Particles ◽

Research Vessel ◽

Long Range Transport ◽

Marine Aerosol ◽

Raman Lidar ◽

Range Transport ◽

Lidar Observations

Abstract. Continuous vertically resolved monitoring of marine aerosol, Saharan dust, and marine/dust aerosol mixtures was performed with multiwavelength polarization/Raman lidar aboard the German research vessel R/V Meteor during a one-month transatlantic cruise from Guadeloupe to Cabo Verde over 4500 km (from 61.5° W to 2&deg W, mostly along 14.5° N) in April–May 2013, as part of SALTRACE (Saharan Aerosol Long-range Transport and Aerosol–Cloud Interaction Experiment). An overview of measured aerosol optical properties over the tropical Atlantic is given in terms of spectrally resolved particle backscatter and extinction coefficients, lidar ratio, and linear depolarization ratio. Height profiles from the marine boundary layer (MBL) up to the top of the Saharan Air Layer (SAL) are presented. MBL and SAL mean lidar ratios were around 20 and 40 sr. These values indicate clean marine conditions in the MBL and entrainment of marine particles into the lower part of the SAL. In the central and upper parts of the SAL, the lidar ratios were most frequently 50–60 sr and thus typical for Saharan dust. The MBL and SAL mean depolarization ratios were close to 0.05 and between 0.2–0.3, respectively, which reflects almost dust-free conditions in the MBL and the occurrence of a mixture of marine and dust particles in the SAL. The conceptual model, describing the long-range transport and removal processes of Saharan dust over the North Atlantic, is discussed and confronted with the lidar observations along the west-to-east track of the slowly moving research vessel. The role of turbulent downward mixing as an efficient dust removal process is illuminated. In a follow-up article (Rittmeister et al., 2017), the lidar observations of dust extinction coefficient and derived mass concentration profiles are compared with respective dust profiles simulated with three well-established European atmospheric aerosol and dust prediction models (MACC, NMMB/BSC-Dust, SKIRON).

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Lidar observations of tropical high-altitude cirrus clouds: results from dual-wavelength Raman lidar measurements during the ALBATROSS campaign 1996

10.1117/12.275163 ◽

1997 ◽

Author(s):

Georg Beyerle ◽

H. J. Schaefer ◽

Otto Schrems ◽

R. Neuber ◽

P. Rairoux ◽

...

Keyword(s):

High Altitude ◽

Cirrus Clouds ◽

Dual Wavelength ◽

Raman Lidar ◽

Lidar Measurements ◽

Lidar Observations

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Fluorescence lidar observations of wildfire smoke inside cirrus: A contribution to smoke-cirrus – interaction research

10.5194/acp-2021-1017 ◽

2021 ◽

Author(s):

Igor Veselovskii ◽

Qiaoyun Hu ◽

Albert Ansmann ◽

Philippe Goloub ◽

Thierry Podvin ◽

...

Keyword(s):

Surface Area ◽

Ice Crystal ◽

Raman Lidar ◽

Upper Troposphere ◽

Wildfire Smoke ◽

Microphysical Properties ◽

Lidar Measurements ◽

Lidar Observations ◽

Interaction Research ◽

Area And Volume

Abstract. A remote sensing method, based on fluorescence lidar measurements, that allows to detect and to quantify the smoke content in upper troposphere and lower stratosphere (UTLS) is presented. The unique point of this approach is that, smoke and cirrus properties are observed in the same air volume simultaneously. In the article, we provide results of fluorescence and multiwavelength Mie-Raman lidar measurements performed at ATOLL observatory from Laboratoire d’Optique Atmosphérique, University of Lille, during strong smoke episodes in the summer and autumn seasons of 2020. The aerosol fluorescence was induced by 355 nm laser radiation and the fluorescence backscattering was measured in a single spectral channel, centered at 466 nm of 44 nm width. To estimate smoke properties, such as number, surface area and volume concentration, the conversion factors, which link the fluorescence backscattering and the smoke microphysical properties, are derived from the synergy of multiwavelength Mie-Raman and fluorescence lidar observations. Based on two case studies, we demonstrate that the fluorescence lidar technique provides possibility to estimate the smoke surface area concentration within freshly formed cirrus layers. This value was used in smoke INP parameterization scheme to predict ice crystal number concentrations in cirrus generation cells.

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Lidar observations of Nabro volcano aerosol layers in the stratosphere over Gwangju, Korea

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-1171-2015 ◽

2015 ◽

Vol 15 (1) ◽

pp. 1171-1191 ◽

Cited By ~ 4

Author(s):

D. Shin ◽

D. Müller ◽

K. Lee ◽

S. Shin ◽

Y. J. Kim ◽

...

Keyword(s):

Lower Stratosphere ◽

Stratospheric Aerosol ◽

Aerosol Layer ◽

Raman Lidar ◽

Backscatter Coefficient ◽

Upper Troposphere ◽

Lidar Measurements ◽

Volcanic Aerosols ◽

Lidar Observations ◽

532 Nm

Abstract. We report on the first Raman lidar measurements of stratospheric aerosol layers in the upper troposphere and lower stratosphere over Korea. The data were taken with the multiwavelength aerosol Raman lidar at Gwangju (35.10° N, 126.53° E), Korea. The volcanic ash particles and gases were released around 12 June 2011 during the eruption of the Nabro volcano (13.37° N, 41.7° E) in Eritrea, east Africa. Forward trajectory computations show that the volcanic aerosols were advected from North Africa to East Asia. The first observation of the stratospheric aerosol layers over Korea was on 19 June 2011. The stratospheric aerosol layers appeared between 15 and 17 km height a.s.l. The aerosol layers' maximum value of the backscatter coefficient and the linear particle depolarization ratio at 532 nm were 1.5 ± 0.3 Mm−1 sr−1 and 2.2%, respectively. We found these values at 16.4 km height a.s.l. 44 days after this first observation, we observed the stratospheric aerosol layer again. We continuously probed the upper troposphere and lower stratosphere for this aerosol layer during the following 5 months, until December 2011. The aerosol layers typically occurred between 10 and 20 km height a.s.l. The stratospheric aerosol optical depth and the maximum backscatter coefficient at 532 nm decreased during these 5 months.

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EARLINET dust observations vs. BSC-DREAM8b modeled profiles: 12-year-long systematic comparison at Potenza, Italy

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-8781-2014 ◽

2014 ◽

Vol 14 (16) ◽

pp. 8781-8793 ◽

Cited By ~ 39

Author(s):

L. Mona ◽

N. Papagiannopoulos ◽

S. Basart ◽

J. Baldasano ◽

I. Binietoglou ◽

...

Keyword(s):

Center Of Mass ◽

Saharan Dust ◽

Raman Lidar ◽

Dust Layer ◽

Systematic Comparison ◽

Dust Extinction ◽

Lidar Measurements ◽

Order Of Magnitude ◽

Lidar Ratio ◽

532 Nm

Abstract. In this paper, we report the first systematic comparison of 12-year modeled dust extinction profiles vs. Raman lidar measurements. We use the BSC-DREAM8b model, one of the most widely used dust regional models in the Mediterranean, and Potenza EARLINET lidar profiles for Saharan dust cases, the largest one-site database of dust extinction profiles. A total of 310 dust cases were compared for the May 2000–July 2012 period. The model reconstructs the measured layers well: profiles are correlated within 5% of significance for 60% of the cases and the dust layer center of mass as measured by lidar and modeled by BSC-DREAM8b differ on average 0.3 ± 1.0 km. Events with a dust optical depth lower than 0.1 account for 70% of uncorrelated profiles. Although there is good agreement in terms of profile shape and the order of magnitude of extinction values, the model overestimates the occurrence of dust layer top above 10 km. Comparison with extinction profiles measured by the Raman lidar shows that BSC-DREAM8b typically underestimates the dust extinction coefficient, in particular below 3 km. Lowest model–observation differences (below 17%) correspond to a lidar ratio at 532 nm and Ångström exponent at 355/532 nm of 60 ± 13 and 0.1 ± 0.6 sr, respectively. These are in agreement with values typically observed and modeled for pure desert dust. However, the highest differences (higher than 85%) are typically related to greater Ångström values (0.5 ± 0.6), denoting smaller particles. All these aspects indicate that the level of agreement decreases with an increase in mixing/modification processes.

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