Summary of research paper submitted* to Atmospheric Chemistry and Physics titled: Optical and microphysical characterization of aerosol layers over South Africa by means of multi-wavelength polarization Raman lidar measurements

Abstract. At CNR-IMAA, an aerosol lidar system is operative since May 2000 in the framework of EARLINET (European Aerosol Research Lidar Network), the first lidar network for tropospheric aerosol study on continental scale. High quality multi-wavelength measurements make this system a reference point for the validation of data products provided by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations), the first satellite-borne lidar specifically designed for aerosol and cloud study. Since 14 June 2006, devoted measurements are performed at CNR-IMAA in coincidence of CALIPSO overpasses. For the first time, results on 1-year comparisons between ground-based multi-wavelength Raman lidar measurements and corresponding CALIPSO lidar Level 1 profiles are presented. A methodology for the comparison is presented and discussed into details. Cases with the detection of cirrus clouds in CALIPSO data are separately analysed for taking into account eventual multiple scattering effects. For cirrus cloud cases, few cases are available to draw any conclusions. For clear sky conditions, the comparison shows good performances of the CALIPSO on-board lidar: the mean relative difference between the ground-based and CALIPSO Level 1 measurements is always within its standard deviation at all altitudes, with a mean difference in the 3–8 km altitude range of (−2±12)%. At altitude ranges corresponding to the typical PBL height observed at CNR-IMAA, a mean underestimation of (−24±20)% is observed in CALIPSO data, probably due to the difference in the aerosol content at the location of PEARL and CALIPSO ground-track location. Finally, the mean differences are on average lower for the closest overpasses (at about 40 km), with an increment of the differences at all altitude ranges when the 80 km overpasses are considered.

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Estimate of rain evaporation rates from dual-wavelength lidar measurements: comparison against a model analytical solution

EPJ Web of Conferences ◽

10.1051/epjconf/201817604002 ◽

2018 ◽

Vol 176 ◽

pp. 04002

Author(s):

Simone Lolli ◽

Paolo Di Girolamo ◽

Belay Demoz ◽

Xiaowen Li ◽

Ellsworth J. Welton

Keyword(s):

Analytical Solution ◽

Evaporation Rate ◽

Dual Wavelength ◽

Raman Lidar ◽

Lidar Measurements ◽

Median Volume ◽

Multi Wavelength

Rain evaporation significantly contributes to moisture and heat cloud budgets. In this paper, we illustrate an approach to estimate the median volume raindrop diameter and the rain evaporation rate profiles from dual-wavelength lidar measurements. These observational results are compared with those provided by a model analytical solution. We made use of measurements from the multi-wavelength Raman lidar BASIL.

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Retrieval of optical and microphysical properties of transported Saharan dust over Athens and Granada based on multi-wavelength Raman lidar measurements: Study of the mixing processes

Atmospheric Environment ◽

10.1016/j.atmosenv.2019.116824 ◽

2019 ◽

Vol 214 ◽

pp. 116824 ◽

Cited By ~ 8

Author(s):

O. Soupiona ◽

S. Samaras ◽

P. Ortiz-Amezcua ◽

C. Böckmann ◽

A. Papayannis ◽

...

Keyword(s):

Saharan Dust ◽

Raman Lidar ◽

Mixing Processes ◽

Microphysical Properties ◽

Lidar Measurements ◽

Multi Wavelength

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Ceilometer aerosol profiling versus Raman lidar in the frame of the INTERACT campaign of ACTRIS

Atmospheric Measurement Techniques ◽

10.5194/amt-8-2207-2015 ◽

2015 ◽

Vol 8 (5) ◽

pp. 2207-2223 ◽

Cited By ~ 27

Author(s):

F. Madonna ◽

F. Amato ◽

J. Vande Hey ◽

G. Pappalardo

Keyword(s):

Atmospheric Aerosols ◽

Signal To Noise Ratio ◽

Cloud Base ◽

Raman Lidar ◽

Backscatter Coefficient ◽

Lidar Measurements ◽

Multi Wavelength ◽

Strong Motivation ◽

Technological Improvements ◽

Aerosol Properties

Abstract. Despite their differences from more advanced and more powerful lidars, the low construction and operation cost of ceilometers (originally designed for cloud base height monitoring) has fostered their use for the quantitative study of aerosol properties. The large number of ceilometers available worldwide represents a strong motivation to investigate both the extent to which they can be used to fill in the geographical gaps between advanced lidar stations and also how their continuous data flow can be linked to existing networks of the more advanced lidars, like EARLINET (European Aerosol Research Lidar Network). In this paper, multi-wavelength Raman lidar measurements are used to investigate the capability of ceilometers to provide reliable information about atmospheric aerosol properties through the INTERACT (INTERcomparison of Aerosol and Cloud Tracking) campaign carried out at the CNR-IMAA Atmospheric Observatory (760 m a.s.l., 40.60° N, 15.72° E), in the framework of the ACTRIS (Aerosol Clouds Trace gases Research InfraStructure) FP7 project. This work is the first time that three different commercial ceilometers with an advanced Raman lidar are compared over a period of 6 months. The comparison of the attenuated backscatter coefficient profiles from a multi-wavelength Raman lidar and three ceilometers (CHM15k, CS135s, CT25K) reveals differences due to the expected discrepancy in the signal to noise ratio (SNR) but also due to changes in the ambient temperature on the short and mid-term stability of ceilometer calibration. Therefore, technological improvements are needed to move ceilometers towards operational use in the monitoring of atmospheric aerosols in the low and free troposphere.

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Ceilometer aerosol profiling vs. Raman lidar in the frame of INTERACT campaign of ACTRIS

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-12407-2014 ◽

2014 ◽

Vol 7 (12) ◽

pp. 12407-12447 ◽

Cited By ~ 4

Author(s):

F. Madonna ◽

F. Amato ◽

J. Vande Hey ◽

G. Pappalardo

Keyword(s):

Atmospheric Aerosol ◽

Correction Function ◽

Cloud Base ◽

Raman Lidar ◽

Lidar Measurements ◽

Multi Wavelength ◽

Strong Motivation ◽

Technological Improvements ◽

First Time ◽

Cloud Tracking

Abstract. Despite their differences from more advanced and more powerful lidars, the low construction and operation cost of ceilometers, originally designed for cloud base height monitoring, has fostered their use for the quantitative study of aerosol properties. The large number of ceilometers available worldwide represents a strong motivation to investigate both the extent to which they can be used to fill in the geographical gaps between advanced lidar stations and also how their continuous data flow can be linked to existing networks of the more advanced lidars, like EARLINET (European Aerosol Research LIdar NETwork). In this paper, multi-wavelength Raman lidar measurements are used to investigate the capability of ceilometers to provide reliable information about atmospheric aerosol content through the INTERACT (INTERcomparison of Aerosol and Cloud Tracking) campaign carried out at the CNR-IMAA Atmospheric Observatory (760 m a.s.l., 40.60° N, 15.72° E), in the framework of ACTRIS (Aerosol Clouds Trace gases Research InfraStructure) FP7 project. This work is the first time that three different commercial ceilometers with an advanced Raman lidar are compared over a period of six months. The comparison of the attenuated backscatter profiles from a multi-wavelength Raman lidar and three ceilometers (CHM15k, CS135s, CT25K) reveals differences due to the expected discrepancy in the SNR but also due to effect of changes in the ambient temperature on the short and mid-term stability of ceilometer calibration. A large instability of ceilometers in the incomplete overlap region has also been observed, making the use of a single overlap correction function for the whole duration of the campaign critical. Therefore, technological improvements of ceilometers towards their operational use in the monitoring of the atmospheric aerosol in the low and free troposphere are needed.

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Technical Note: One year of Raman-lidar measurements in Gual Pahari EUCAARI site close to New Delhi in India – Seasonal characteristics of the aerosol vertical structure

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-4513-2012 ◽

2012 ◽

Vol 12 (10) ◽

pp. 4513-4524 ◽

Cited By ~ 46

Author(s):

M. Komppula ◽

T. Mielonen ◽

A. Arola ◽

K. Korhonen ◽

H. Lihavainen ◽

...

Keyword(s):

Technical Note ◽

New Delhi ◽

Aerosol Layer ◽

Raman Lidar ◽

Extinction Coefficients ◽

Seasonal Characteristics ◽

Lidar Measurements ◽

Multi Wavelength ◽

Lidar Ratio ◽

One Year

Abstract. One year of multi-wavelength (3 backscatter + 2 extinction + 1 depolarization) Raman lidar measurements at Gual Pahari, close to New Delhi, were analysed. The data was split into four seasons: spring (March–May), summer (June–August), autumn (September–November) and winter (December–February). The vertical profiles of backscatter, extinction, and lidar ratio and their variability during each season are presented. The measurements revealed that, on average, the aerosol layer was at its highest in spring (5.5 km). In summer, the vertically averaged (between 1–3 km) backscatter and extinction coefficients had the highest averages (3.3 Mm−1 sr−1 and 142 Mm−1 at 532 nm, respectively). Aerosol concentrations were slightly higher in summer compared to other seasons, and particles were larger in size. The autumn showed the highest lidar ratio and high extinction-related Ångström exponents (AEext), indicating the presence of smaller probably absorbing particles. The winter had the lowest backscatter and extinction coefficients, but AEext was the highest, suggesting still a large amount of small particles.

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