Micro Pulse Lidar measurements in coincidence with CALIPSO overpasses: Comparison of tropospheric aerosols over Kattankulathur (12.82oN, 80.04oE)

2021 ◽  
pp. 101082
Author(s):  
A. Aravindhavel ◽  
Sanjay Kumar Mehta ◽  
Saleem Ali ◽  
T.V. Ramesh Reddy ◽  
Vanmathi Annamali ◽  
...  
Keyword(s):  
Lidar Measurements ◽  
Tropospheric Aerosols ◽  
Micro Pulse Lidar

scholarly journals A study on the aerosol extinction-to-backscatter ratio with combination of micro-pulse LIDAR and MODIS over Hong Kong

2006 ◽  
Vol 6 (11) ◽  
pp. 3243-3256 ◽  
Author(s):  
Q. S. He ◽  
C. C. Li ◽  
J. T. Mao ◽  
A. K. H. Lau ◽  
P. R. Li
Keyword(s):  
Hong Kong ◽  
Aerosol Extinction ◽  
Scattering Coefficients ◽  
Aerosol Scattering ◽  
Microphysical Parameters ◽  
Lidar Measurements ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Lidar Equation ◽  
Micro Pulse Lidar

Abstract. The aerosol extinction-to-backscatter ratio is an important parameter for inverting LIDAR signals in the LIDAR equation. It is a complicated function of the aerosol microphysical characteristics. In this paper, a method to retrieve the column-averaged aerosol extinction-to-backscatter ratio by constraining the aerosol optical depths (AOD) from a Micro-pulse LIDAR (MPL) by the AOD measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Both measurements were taken on cloud free days between 1 May 2003 and 30 June 2004 over Hong Kong, a coastal city in south China. Simultaneous measurements of aerosol scattering coefficients with a forward scattering visibility sensor are compared with the LIDAR retrieval of aerosol extinction coefficients. The data are then analyzed to determine seasonal trends of the aetrosol extinction-to-backscatter ratio. In addition, the relationships between the extinction-to-backscatter ratio and wind conditions as well as other aerosol microphysical parameters are presented. The mean aerosol extinction-to-backscatter ratio for the whole period was found to be 29.1±5.8 sr, with a minimum of 18 sr in July 2003 and a maximum of 44 sr in March 2004. The ratio is lower in summer because of the dominance of oceanic aerosols in association with the prevailing southwesterly monsoon. In contrast, relatively larger ratios are noted in spring and winter because of the increased impact of local and regional industrial pollutants associated with the northerly monsoon. The extended LIDAR measurements over Hong Kong provide not only a more accurate retrieval of aerosol extinction coefficient profiles, but also significant substantial information for air pollution and climate studies in the region.

scholarly journals Intercomparison of aerosol measurements performed with multi-wavelength Raman lidars, automatic lidars and ceilometers in the frame of INTERACT-II campaign

2017 ◽  
Author(s):  
Fabio Madonna ◽  
Marco Rosoldi ◽  
Simone Lolli ◽  
Francesco Amato ◽  
Joshua Vande Hey ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Trace Gases ◽  
Average Difference ◽  
Raman Lidar ◽  
Simultaneous Measurements ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Micro Pulse Lidar ◽  
Aerosol Properties ◽  
Cloud Tracking

Abstract. Following on from the previous efforts of INTERACT (INTERcomparison of Aerosol and Cloud Tracking), the INTERACT-II campaign used multi-wavelength Raman lidar measurements to assess the performance of an automatic compact micro-pulse lidar (MiniMPL) and two ceilometers (CL51 and CS135), respectively, to provide reliable information about optical and geometric atmospheric aerosol properties. The campaign took place at the CNR-IMAA Atmospheric Observatory (760 m asl, 40.60° N, 15.72° E), in the framework of the ACTRIS-2 (Aerosol Clouds Trace gases Research InfraStructure) H2020 project. Co-located simultaneous measurements involving a MiniMPL, two ceilometers, and two EARLINET multi-wavelength Raman lidars (MUSA and PEARL) were performed from July to December 2016. Range-corrected signals (RCS) of MiniMPL showed an average difference with respect to MUSA/PEARL RCS of less than 10–15 % below 3.0 km above sea level, largely due to the use of an inaccurate overlap correction, and smaller than 5 % in the free troposphere. For the CL51, the average difference with respect to MUSA/PEARL attenuated backscatter is

scholarly journals Intercomparison of aerosol measurements performed with multi-wavelength Raman lidars, automatic lidars and ceilometers in the framework of INTERACT-II campaign

2018 ◽  
Vol 11 (4) ◽  
pp. 2459-2475 ◽  
Author(s):  
Fabio Madonna ◽  
Marco Rosoldi ◽  
Simone Lolli ◽  
Francesco Amato ◽  
Joshua Vande Hey ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Raman Lidar ◽  
Calibration Constant ◽  
Normalization Constant ◽  
Fractional Difference ◽  
Seasonal Behavior ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Micro Pulse Lidar ◽  
Cloud Tracking

Abstract. Following the previous efforts of INTERACT (INTERcomparison of Aerosol and Cloud Tracking), the INTERACT-II campaign used multi-wavelength Raman lidar measurements to assess the performance of an automatic compact micro-pulse lidar (MiniMPL) and two ceilometers (CL51 and CS135) in providing reliable information about optical and geometric atmospheric aerosol properties. The campaign took place at the CNR-IMAA Atmospheric Observatory (760 ma.s.l.; 40.60∘ N, 15.72∘ E) in the framework of ACTRIS-2 (Aerosol Clouds Trace gases Research InfraStructure) H2020 project. Co-located simultaneous measurements involving a MiniMPL, two ceilometers and two EARLINET multi-wavelength Raman lidars were performed from July to December 2016. The intercomparison highlighted that the MiniMPL range-corrected signals (RCSs) show, on average, a fractional difference with respect to those of CNR-IMAA Atmospheric Observatory (CIAO) lidars ranging from 5 to 15 % below 2.0 km a.s.l. (above sea level), largely due to the use of an inaccurate overlap correction, and smaller than 5 % in the free troposphere. For the CL51, the attenuated backscatter values have an average fractional difference with respect to CIAO lidars < 20–30 % below 3 km and larger above. The variability of the CL51 calibration constant is within ±46 %. For the CS135, the performance is similar to the CL51 below 2.0 kma.s.l., while in the region above 3 kma.s.l. the differences are about ±40 %. The variability of the CS135 normalization constant is within ±47 %. Finally, additional tests performed during the campaign using the CHM15k ceilometer operated at CIAO showed the clear need to investigate the CHM15k historical dataset (2010–2016) to evaluate potential effects of ceilometer laser fluctuations on calibration stability. The number of laser pulses shows an average variability of 10 % with respect to the nominal power which conforms to the ceilometer specifications. Nevertheless, laser pulses variability follows seasonal behavior with an increase in the number of laser pulses in summer and a decrease in winter. This contributes to explain the dependency of the ceilometer calibration constant on the environmental temperature hypothesized during INTERACT.

scholarly journals Experimental calibration assessment of a MPLNET/Micro-Pulse Lidar system in comparison with EARLINET lidar measurements for aerosol optical properties retrieval

2020 ◽  
Author(s):  
Carmen Córdoba-Jabonero ◽  
Albert Ansmann ◽  
Cristofer Jiménez ◽  
Holger Baars ◽  
María-Ángeles López-Cayuela ◽  
...  
Keyword(s):  
Optical Properties ◽  
Depolarization Ratio ◽  
Backscatter Coefficient ◽  
Experimental Calibration ◽  
Experimental Procedure ◽  
Lidar Measurements ◽  
Total Particle ◽  
Linear Depolarization Ratio ◽  
Micro Pulse Lidar ◽  
The Impact

Abstract. Simultaneous observations of a polarized Micro-Pulse Lidar (P-MPL) system, currently operative within MPLNET (NASA Micro-Pulse Lidar Network), with two referenced EARLINET (European Aerosol Research Lidar Network) lidars, running at Leipzig site (Germany, 51.4º N 12.4º E, 125 m a.s.l.), were performed during a comprehensive two-month field campaign in summer 2019. A calibration assessment regarding the overlap (OVP) correction of the P-MPL signal profiles and its impact in the retrieval of the optical properties is achieved, describing also the experimental procedure used. The optimal lidar-specific OVP function for correcting the P-MPL measurements is experimentally determined, highlighting that the OVP function as delivered by the P-MPL manufacturer cannot be used. Among the OVP functions examined, the averaged one between those obtained from the comparison of the P-MPL observations with those of the other two referenced lidars seems to be the best proxy at both near- and far-field ranges. In addition, the impact of the OVP function in the accuracy of the retrieved profiles of the total particle backscatter coefficient (PBC) and the particle linear depolarization ratio (PLDR) is examined. First, the volume linear depolarization ratio (VLDR) profile is obtained and compared to the reference lidars, showing it needs to be corrected by a small offset value within a good accuracy. Once P-MPL measurements are optimally OVP-corrected, the PBC profiles (and hence the PLDR ones) can be derived using the Klett-Fernald approach. In addition, an alternative method based on the separation of the total PBC into their aerosol components is presented in order to estimate the total particle extinction coefficient (PEC) profile, and hence the Aerosol Optical Depth, from elastic P-MPL measurements. A dust event as observed at Leipzig in June 2019 is used for illustration. In overall, an adequate OVP function is needed to be determined in a regular basis to calibrate the P-MPL system in order to derive suitable aerosol products.

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