scholarly journals Seasonal variability of aerosol optical properties observed by means of a Raman lidar at an EARLINET site over Northeastern Spain

2011 ◽  
Vol 11 (1) ◽  
pp. 175-190 ◽  
Author(s):  
M. Sicard ◽  
F. Rocadenbosch ◽  
M. N. M. Reba ◽  
A. Comerón ◽  
S. Tomás ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Planetary Boundary Layer ◽  
Optical Thickness ◽  
Seasonal Variability ◽  
Aerosol Optical Thickness ◽  
Saharan Dust ◽  
Raman Lidar ◽  
Aerosol Optical Properties ◽  
Lidar Ratio

Abstract. The annual and seasonal variability of aerosol optical properties observed by means of a Raman lidar over Northeastern Spain has been assessed. The lidar representativeness has first been checked against sun-photometer measurements in terms of aerosol optical thickness. Then the annual cycle and the seasonal variability of the planetary boundary layer aerosol optical thickness and its fraction compared to the columnar optical thickness, the lidar ratio, the backscatter-related Ångström exponent and the planetary boundary layer height are analyzed and discussed. Winter and summer mean profiles of extinction, backscatter and lidar ratio retrieved with the Raman algorithm are presented. The analysis shows the impact of most of the natural events (Saharan dust intrusions, wildfires, etc.) and meteorological situations (summer anticyclonic situation, the formation of the Iberian thermal low, winter long-range transport from North Europe and/or North America, re-circulation flows, etc.) occurring in the Barcelona area. A detailed study of a special event including a combined intrusion of Saharan dust and biomass-burning particles proves the suitability of combining the retrieval of aerosol optical properties from Raman and pure elastic lidar measurements to discriminate spatially different types of aerosols and to follow their spatial and temporal evolution.

scholarly journals Seasonal variability of aerosol optical properties observed by means of an elastic-Raman lidar over Northeastern Spain

2010 ◽  
Vol 10 (6) ◽  
pp. 14053-14094
Author(s):  
M. Sicard ◽  
M. N. M. Reba ◽  
F. Rocadenbosch ◽  
A. Comerón ◽  
S. Tomás ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Planetary Boundary Layer ◽  
Optical Thickness ◽  
Seasonal Variability ◽  
Aerosol Optical Thickness ◽  
Saharan Dust ◽  
Raman Lidar ◽  
Aerosol Optical Properties ◽  
Lidar Ratio

Abstract. The annual and seasonal variability of aerosol optical properties observed by means of an elastic-Raman lidar over Northeastern Spain has been assessed. The lidar representativeness has first been checked against sun-photometer measurements in terms of aerosol optical thickness. Then the annual cycle and the seasonal variability of the planetary boundary layer aerosol optical thickness and its fraction compared to the columnar optical thickness, the lidar ratio, the backscatter-related Ångström exponent and the planetary boundary layer height have been analyzed and discussed. Winter and summer mean profiles of extinction, backscatter and lidar ratio retrieved with the Raman algorithm have been presented. The analysis shows the impact of most of the natural events (Saharan dust intrusions, wildfires, etc.) and meteorological situations (summer anticyclonic situation, the formation of the Iberian thermal low, winter long-range transport from North Europe and/or North America, re-circulation flows, etc.) occurring in the Barcelona area. A detail study of a special event including a combined intrusion of Saharan dust and biomass-burning particles has proven the suitability of combining nighttime Raman- and daytime pure elastic-inversions to discriminate spatially different types of aerosols and to follow their spatial and temporal evolution.

scholarly journals Seventeen-year systematic measurements of dust aerosol optical properties using the eole ntua lidar system (2000-2016)

2018 ◽  
Vol 176 ◽  
pp. 05029
Author(s):  
Ourania Soupiona ◽  
Maria Mylonaki ◽  
Alexandros Papayannis ◽  
Athina Argyrouli ◽  
Panayotis Kokkalis ◽  
...  
Keyword(s):  
Optical Properties ◽  
Mean Value ◽  
Saharan Dust ◽  
Aerosol Optical Properties ◽  
Mean Values ◽  
Time Period ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
Dust Events

A comprehensive analysis of the seasonal variability of the optical properties of Saharan dust aerosols over Athens, Greece, is presented for a 17-year time period (2000-2016), as derived from multi-wavelength Raman lidar measurements (57 dust events with more than 80 hours of measurements). The profiles of the derived aerosol optical properties (aerosol backscatter and extinction coefficients, lidar ratio and aerosol Ångström exponent) at 355 nm are presented. For these dust events we found a mean value of the lidar ratio of ~52±13 sr at 355 nm and of ~58±8 sr (not shown) at 532 nm (2-4 km a.s.l. height). For our statistical analysis, presented here, we used monthly-mean values and time periods under cloud-free conditions. The number of dust events was greatest in late spring, summer, and early autumn periods. In this paper we also present a selected case study (04 April 2016) of desert dust long-range transport from the Saharan desert.

Optical Properties of Aerosol in Planetary Boundary Layer Measured by Raman Lidar at Hefei in Summer and Autumn

2010 ◽  
Vol 37 (10) ◽  
pp. 2526-2532 ◽  
Author(s):  
伯广宇 Bo Guangyu ◽  
谢晨波 Xie Chenbo ◽  
刘东 Liu Dong ◽  
陈涛 Chen Tao ◽  
王邦新 Wang Bangxin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Planetary Boundary Layer ◽  
Raman Lidar

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

2014 ◽  
Vol 14 (16) ◽  
pp. 8781-8793 ◽  
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.

scholarly journals Lidar Measuremnt on Dust Transport from the Saharan Desert to the Iran Plateau

2020 ◽  
Vol 237 ◽  
pp. 02020
Author(s):  
Hossein Panahifar ◽  
Ruhollah Moradhaseli ◽  
Hadi Bourzoie ◽  
Mahdi Gholami ◽  
Hamid Reza Khalesifard
Keyword(s):  
Trajectory Analysis ◽  
Saharan Dust ◽  
Dust Particles ◽  
Raman Lidar ◽  
Dust Layer ◽  
Mean Values ◽  
Dust Transport ◽  
Lidar Ratio ◽  
532 Nm ◽  
Iran Plateau

Optical properties of long-range Saharan dust particles transported to the Iran Plateau have been investigated. The results were derived from the measurements of a dual-wavelength Depolarized backscatter/Raman lidar and a Cimel CE318-2 sunphotometer. Observations were performed in Zanjan, Northwest Iran. The backward trajectory analysis show that the lofted dust plumes come from the Saharan desert and travel along Mediterranean Sea and Turkey toward Iran. The lidar ratio within the lofted dust layer has been found with mean values of 50 sr at 532 nm. For the depolarization ratio, mean values of 25% have been found.

Characterization of the time evolution of the PBL structure and dry-layers based on the us of Raman Lidar measurements collected during HYMEX-SOP1

2021 ◽  
Author(s):  
Donato Summa ◽  
Paolo Di Girolamo ◽  
Noemi Franco ◽  
Benedetto De Rosa ◽  
Fabio Madonna ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Water Vapour ◽  
Planetary Boundary Layer ◽  
Grid Point ◽  
Laser Source ◽  
Raman Lidar ◽  
Water Vapour Concentration ◽  
Vapour Concentration

<p>The exchange processes between the Earth and the atmosphere play a crucial role in the development of the Planetary Boundary Layer (PBL). Different remote sensing techniques can provide PBL measurement with different spatial and temporal resolutions. Vertical profiles of atmospheric thermodynamic variables, i.e.  temperature and humidity, or wind speed, clouds and aerosols can be used as proxy to retrieve PBL height from active and passive remote sensing instruments. The University of BASILicata ground-based Raman Lidar system (BASIL) was deployed in the North-Western Mediterranean basin in the Cévennes-Vivarais site (Candillargues, Southern France, Lat: 43°37' N, Long: 4° 4' E, Elev: 1 m) and operated between 5 September and 5 November 2012, collecting more than 600 hours of measurements, distributed over 51 days and 19 intensive observation periods (IOPs). BASIL is capable to provide high-resolution and accurate measurements of atmospheric temperature and water vapour, both in daytime and night-time, based on the application of the rotational and vibrational Raman lidar techniques in the UV. This measurement capability makes BASIL a key instrument for the characterization of the water vapour concentration. BASIL makes use of a Nd:YAG laser source capable of emitting pulses at 355, 532 and 1064 nm, with a single pulse energy at 355nm of 500 mJ [1] .In the presented research effort, water vapour concentration was  computed and used to determine the PBL height. [2]. A dynamic index  included in the European Centre for Medium-range Weather Forecasts (ECMWF) ERA5 atmospheric reanalysis (CAPE, Friction velocity, etc.) is also considered and compared with BASIL resutls. ERA5 provides hourly data on regular latitude-longitude grids at 0.25° x 0.25° resolution at 37 pressure levels [3]. ERA5 is publicly available through the Copernicus Climate Data Store (CDS, https://cds.climate.copernicus.eu).  In order to properly carry out the comparison, the nearest ERA5 grid point to the lidar site has been considered assuming the representativeness uncertainty due to the use of the nearest grid-point comparable with other methods (e.g. kriging, bilinear interpolation, etc.). More results from this  measurement  effort will  be reported and discussed at the Conference.</p><p><strong>Reference</strong></p><p>[1] Di Girolamo, Paolo, De Rosa, Benedetto, Flamant, Cyrille, Summa, Donato, Bousquet, Olivier, Chazette, Patrick, Totems, Julien, Cacciani, Marco. Water vapor mixing ratio and temperature inter-comparison results in the framework of the Hydrological Cycle in the Mediterranean Experiment—Special Observation Period 1. BULLETIN OF ATMOSPHERIC SCIENCE AND TECHNOLOGY, ISSN: 2662-1495, doi: 10.1007/s42865-020-00008-3</p><p>[2] D. Summa, P. Di Girolamo, D. Stelitano, and M. Cacciani. Characterization of the planetary boundary layer height and structure by Raman lidar: comparison of different approaches  Atmos. Meas. Tech., 6, 3515–3525, 2013 www.atmos-meas-tech.net/6/3515/2013/doi:10.5194/amt-6-3515-2013</p><p>[3] Hersbach et al. The ERA5 global reanalysis Hans  https://doi.org/10.1002/qj.3803[3]</p>

scholarly journals Analyzing the turbulence in the Planetary Boundary Layer by the synergic use of remote sensing systems: Doppler wind lidar and aerosol elastic lidar

2018 ◽  
Author(s):  
Gregori de Arruda Moreira ◽  
Juan Luís Guerrero-Rascado ◽  
Jose Antonio Benavent-Oltra ◽  
Pablo Ortiz-Amezcua ◽  
Roberto Román ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Weather Forecasting ◽  
Saharan Dust ◽  
Aerosol Layer ◽  
Frequency Distributions ◽  
Sensing Systems ◽  
Turbulent Characteristics ◽  
Remote Sensing Systems

Abstract. The Planetary Boundary Layer (PBL) is the lowermost region of troposphere and endowed with turbulent characteristics, which can have mechanical or thermodynamic origins. Such behavior gives to this layer great importance, mainly in studies about pollutant dispersion and weather forecasting. However, the instruments usually applied in studies about turbulence in the PBL have limitations in spatial resolution (anemometer towers) or temporal resolution (aircrafts). In this study we propose the synergetic use of remote sensing systems (microwave radiometer [MWR], Doppler lidar [DL] and elastic lidar [EL]) to analyze the PBL behavior. Furthermore, we show how some meteorological variables such as air temperature, aerosol number density, vertical wind, relative humidity and net radiation might influence the PBL dynamic. The statistical moments of the high frequency distributions of the vertical velocity, derived from DL and of the backscattered coefficient derived from EL, are corrected by two methodologies, namely first lag and −2/3 correction. The corrected profiles present small differences when compare against the uncorrected profiles, showing low influence of noise and the viability of the proposed methodology. Two case studies were analyzed in detail, one corresponding to a well-defined PBL and another one corresponding to a situation with presence of a Saharan dust lofted aerosol layer and clouds. In both cases the results provided by the different instruments are complementary, thus the synergistic use of the different systems allow us performing a detailed monitoring of the PBL.

scholarly journals Detection of Saharan dust and biomass burning events using near real-time intensive aerosol optical properties in the northwestern Mediterranean

2016 ◽  
Author(s):  
M. Ealo ◽  
A. Alastuey ◽  
A. Ripoll ◽  
N. Pérez ◽  
M. C. Minguillón ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Mineral Dust ◽  
Organic Aerosol ◽  
Saharan Dust ◽  
Aerosol Optical Properties ◽  
Angstrom Exponent ◽  
Ångström Exponent ◽  
Dust Events ◽  
Ångstrom Exponent

Abstract. The study of Saharan dust events (SDE) and biomass burning (BB) emissions are both topic of great scientific interest since they are frequent and important polluting scenarios affecting air quality and climate. The main aim of this work is evaluating the feasibility of using near real-time in situ aerosol optical measurements for the detection of these atmospheric events in the Western Mediterranean Basin (WMB). With this aim, intensive aerosol optical properties (SAE: scattering Ångström exponent, AAE: absorption Ångström exponent, SSAAE: single scattering albedo Ångström exponent, and g: asymmetry parameter) were derived from multi-wavelength aerosol light scattering, hemispheric backscattering and absorption measurements performed at regional (Montseny; MSY, 720 m a.s.l.) and continental (Montsec; MSA, 1570 m a.s.l.) background sites in the WMB. A sensitivity study aiming at calibrating the measured intensive optical properties for SDE and BB detection is presented and discussed. The detection of Saharan dust events (SDE) by means of the SSAAE parameter and Ångström matrix depended on the altitude of the measurement station, and on SDE intensity. At MSA (mountain-top site) SSAAE detected around 85% of SDE compared with 50% at MSY station, where pollution episodes dominated by fine anthropogenic particles frequently masked the effect of mineral dust on optical properties during less intense SDE. Furthermore, an interesting feature of SSAAE was its capability to detect the presence of mineral dust after the end of SDE. Thus, resuspension processes driven by summer regional atmospheric circulations and dry conditions after SDE favored the accumulation of mineral dust at regional level having important consequences for air quality. On average, SAE, AAE and g ranged between -0.7 and 1, 1.3 and 2.5, and 0.5 and 0.75, respectively, during SDE. Based on the Aethalometer model, biomass burning (BB) contribution to equivalent black carbon (BC) accounted for 36% and 40% at MSY and MSA respectively. Linear relationships were found between AAE and %BCbb, with AAE values reaching around 1.5 when %BCbb was higher than 50%. BB contribution to organic matter (OM) at MSY was around 30%. Thus FF combustion sources showed important contributions to both BC and OM in the region under study. Results for OM source apportionment showed good agreement with simultaneous biomass burning organic aerosol (BBOA) and hydrocarbon-like organic aerosol (HOA) calculated from Positive Matrix Factorization (PMF) applied to simultaneous Aerosol Mass Spectrometer (ACSM) measurements. A wildfire episode was identified at MSY, showing AAE values up to 2 when daily BB contributions to BC and OM were 73% and 78% respectively.

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