scholarly journals Vertical profiles of dust and other aerosol types above a coastal site

2019 ◽  
Vol 99 ◽  
pp. 02005
Author(s):  
Dietrich Althausen ◽  
Silke Mewes ◽  
Birgit Heese ◽  
Julian Hofer ◽  
Yoav Schechner ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Spherical Particles ◽  
Vertical Profiles ◽  
Threshold Values ◽  
Small Particles ◽  
Coastal Site ◽  
Lidar Measurements ◽  
Aerosol Types ◽  
Aerosol Type

Monthly mean vertical profiles of aerosol type occurrences are determined from multiwavelength Raman and polarization lidar measurements above Haifa, Israel, in 2017. This contribution presents the applied methods and threshold values. The results are discussed for one example, May 2017. This month shows more often large, non-spherical particles in lofted layers than within the planetary boundary layer. Small particles are observed at higher altitudes only when they are observed in lower altitudes, too.

The Growth of the Planetary Boundary Layer at a Coastal Site: a Case Study

2011 ◽  
Vol 139 (3) ◽  
pp. 521-541 ◽  
Author(s):  
Ferdinando De Tomasi ◽  
M. Marcello Miglietta ◽  
M. Rita Perrone
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Coastal Site

scholarly journals Aerosol classification using airborne High Spectral Resolution Lidar measurements – methodology and examples

2012 ◽  
Vol 5 (1) ◽  
pp. 73-98 ◽  
Author(s):  
S. P. Burton ◽  
R. A. Ferrare ◽  
C. A. Hostetler ◽  
J. W. Hair ◽  
R. R. Rogers ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
High Spectral Resolution ◽  
Color Ratio ◽  
Lidar Measurements ◽  
Aerosol Classification ◽  
Langley Research Center ◽  
High Spectral Resolution Lidar ◽  
Aerosol Types ◽  
532 Nm ◽  
Aerosol Type

Abstract. The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 aircraft has acquired extensive datasets of aerosol extinction (532 nm), aerosol optical depth (AOD) (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 18 field missions that have been conducted over North America since 2006. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, backscatter color ratio, and spectral depolarization ratio) are shown to vary with location and aerosol type. A methodology based on observations of known aerosol types is used to qualitatively classify the extensive set of HSRL aerosol measurements into eight separate types. Several examples are presented showing how the aerosol intensive parameters vary with aerosol type and how these aerosols are classified according to this new methodology. The HSRL-based classification reveals vertical variability of aerosol types during the NASA ARCTAS field experiment conducted over Alaska and northwest Canada during 2008. In two examples derived from flights conducted during ARCTAS, the HSRL classification of biomass burning smoke is shown to be consistent with aerosol types derived from coincident airborne in situ measurements of particle size and composition. The HSRL retrievals of AOD and inferences of aerosol types are used to apportion AOD to aerosol type; results of this analysis are shown for several experiments.

scholarly journals On the spectral depolarisation and lidar ratio of mineral dust provided in the AERONET version 3 inversion product

2018 ◽  
Author(s):  
Sung-Kyun Shin ◽  
Matthias Tesche ◽  
Kwanchul Kim ◽  
Maria Kezoudi ◽  
Boyan Tatarov ◽  
...  
Keyword(s):  
Great Basin ◽  
Reference Values ◽  
Mineral Dust ◽  
Depolarisation Ratio ◽  
Abstract Knowledge ◽  
Lidar Measurements ◽  
Lidar Ratio ◽  
Aerosol Types ◽  
Lidar Observations ◽  
Aerosol Type

Abstract. Knowledge of the particle lidar ratio (Sλ) and the particle linear depolarisation ratio (δλ) for different aerosol types allows for aerosol typing and aerosol-type separation in lidar measurements. Reference values generally originate from dedicated lidar observations but might also be obtained from the inversion of AERONET sun/sky radiometer measurements. This study investigates the consistency of spectral Sλ and δλ provided in the recently released AERONET version 3 inversion product for observations of undiluted mineral dust in the vicinity of major deserts: Gobi, Sahara, Arabian, Great Basin and Great Victoria deserts. Pure dust conditions are identified by an Ångstöm exponent

Characterization of the planetary boundary layer during SAMUM-2 by means of lidar measurements

Tellus B ◽  
2011 ◽  
Vol 63 (4) ◽  
Author(s):  
Silke Groß ◽  
Josef Gasteiger ◽  
Volker Freudenthaler ◽  
Matthias Wiegner ◽  
Alexander Geiß ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Lidar Measurements

scholarly journals Impact of stratospheric intrusions and intercontinental transport on ozone at Jungfraujoch in 2005: comparison and validation of two Lagrangian approaches

2009 ◽  
Vol 9 (10) ◽  
pp. 3371-3383 ◽  
Author(s):  
J. Cui ◽  
M. Sprenger ◽  
J. Staehelin ◽  
A. Siegrist ◽  
M. Kunz ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
North American ◽  
Dispersion Model ◽  
Sensitivity Study ◽  
Particle Dispersion ◽  
Threshold Values ◽  
The North ◽  
Intercontinental Transport ◽  
Stratospheric Intrusions

Abstract. The particle dispersion model FLEXPART and the trajectory model LAGRANTO are Lagrangian models which are widely used to study synoptic-scale atmospheric air flows such as stratospheric intrusions (SI) and intercontinental transport (ICT). In this study, we focus on SI and ICT events particularly from the North American planetary boundary layer for the Jungfraujoch (JFJ) measurement site, Switzerland, in 2005. Two representative cases of SI and ICT are identified based on measurements recorded at Jungfraujoch and are compared with FLEXPART and LAGRANTO simulations, respectively. Both models well capture the events, showing good temporal agreement between models and measurements. In addition, we investigate the performance of FLEXPART and LAGRANTO on representing SI and ICT events over the entire year 2005 in a statistical way. We found that the air at JFJ is influenced by SI during 19% (FLEXPART) and 18% (LAGRANTO), and by ICT from the North American planetary boundary layer during 13% (FLEXPART) and 12% (LAGRANTO) of the entire year. Through intercomparsion with measurements, our findings suggest that both FLEXPART and LAGRANTO are well capable of representing SI and ICT events if they last for more than 12 h, whereas both have problems on representing short events. For comparison with in-situ observations we used O3 and relative humidity for SI events. As parameters to trace ICT events we used a combination of NOy/CO and CO, however these parameters are not specific enough to distinguish aged air masses by their source regions. Moreover, a sensitivity study indicates that the agreement between models and measurements depends significantly on the threshold values applied to the individual control parameters. Generally, the less strict the thresholds are, the better the agreement between models and measurements. Although the dependence of the agreement on the threshold values is appreciable, it nevertheless confirms the conclusion that both FLEXPART and LAGRANTO are well able to capture SI and ICT events with duration longer than 12 h.

scholarly journals Target categorization of aerosol and clouds by continuous multiwavelength-polarization lidar measurements

2017 ◽  
Author(s):  
Holger Baars ◽  
Patric Seifert ◽  
Ronny Engelmann ◽  
Ulla Wandinger
Keyword(s):  
Spherical Particles ◽  
Atmospheric Parameters ◽  
Hygroscopic Growth ◽  
Backscatter Coefficient ◽  
Small Particles ◽  
Data Set ◽  
Quasi Particle ◽  
Lidar Measurements ◽  
Temporal And Spatial ◽  
Large Spherical

Abstract. Absolute calibrated signals at 532 and 1064 nm and the depolarization ratio from a multiwavelength lidar are used to categorize primary aerosol but also clouds in high temporal and spatial resolution. Automatically derived particle backscatter coefficient profiles in low temporal resolution (30 min) are applied to calibrate the lidar signals. From these calibrated lidar signals, new atmospheric parameters in temporally high resolution (quasi particle backscatter coefficient) are derived. By using thresholds obtained from multi-year, multi-site EARLINET measurements, four aerosol classes (small; large, spherical; large, non-spherical; mixed, partly non-spherical) and several cloud classes (liquid, ice) are defined. Thus, particles are classified by their physical feature (shape and size) instead of a classification by source. The methodology is applied to two months of continuous observations (24 hours, 7 days a week) with the multiwavelength-Raman-polarization lidar PollyXT during the HOPE campaign in spring 2013. Cloudnet equipment was operated continuously directly next to the lidar and is used for comparison. By discussing three 24-h case studies, it is shown that the aerosol discrimination is very feasible and informative and gives a good complement to the Cloudnet target categorization. By analyzing the entire HOPE campaign, almost 1 million pixel (5 min times 30 m) could be successfully classified from the two months data set with the newly developed tool. We find that the majority of the aerosol, trapped in the planetary boundary layer (PBL), were small particles as expected for a heavily populated and industrialized area. Large, spherical aerosol was observed mostly at the top of the PBL and close to the identified cloud bases indicating the importance of hygroscopic growth of the particles at high relative humidity. Interestingly, it is found that on several days non-spherical particles were dispersed into the atmosphere from ground.

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