scholarly journals CADEX and beyond: Installation of a new PollyXT site in Dushanbe

2019 ◽  
Vol 99 ◽  
pp. 02010
Author(s):  
Ronny Engelmann ◽  
Julian Hofer ◽  
Abduvosit N. Makhmudov ◽  
Holger Baars ◽  
Karsten Hanbuch ◽  
...  
Keyword(s):  
Asian Dust ◽  
Raman Lidar ◽  
Technical Institute ◽  
Lidar System ◽  
Microphysical Properties ◽  
Source Regions ◽  
Central Asian ◽  
Lidar Measurements ◽  
Academy Of Sciences

During the 18-month Central Asian Dust Experiment we conducted continuous lidar measurements at the Physical Technical Institute of the Academy of Sciences of Tajikistan in Dushanbe between 2015 and 2016. Mineral dust plumes from various source regions have been observed and characterized in terms of their occurrence, and their optical and microphysical properties with the Raman lidar PollyXT. Currently a new container-based lidar system is constructed which will be installed for continuous long-term measurements in Dushanbe.

scholarly journals Optical Measurement of Asian Dust over Daejeon City in 2016 by Depolarization Lidar in AD-Network

2018 ◽  
Vol 176 ◽  
pp. 09015
Author(s):  
Park Chan Bong ◽  
Atsushi Shimizu ◽  
Nobuo Sugimoto
Keyword(s):  
Optical Measurement ◽  
Asian Dust ◽  
Lidar System ◽  
Comparison Results ◽  
Lidar Measurements ◽  
Mass Concentrations

Long-term sustained heavy Asian Dust below 3 km was measured in the period of April 22-26 by 2-wavelengths depolarization lidar system. As the comparison results of Daejeon station with other stations in the AD-Net, similarly formed Asian dust had been measured at Nigata, Toyama, Matsue, and Sendai. The route of the dust was examined by HYSPLIT. More than 80 μg / m3 mass concentrations derived from the lidar measurements were compared with Air-Korea PM10 data.

scholarly journals Mineral dust in central asia: 18-month lidar measurements in tajikistan during the central Asian dust experiment (CADEX)

2018 ◽  
Vol 176 ◽  
pp. 04001 ◽  
Author(s):  
Julian Hofer ◽  
Dietrich Althausen ◽  
Sabur F. Abdullaev ◽  
Abduvosit Makhmudov ◽  
Bakhron I. Nazarov ◽  
...  
Keyword(s):  
Central Asia ◽  
Long Range ◽  
Mineral Dust ◽  
Asian Dust ◽  
Climate System ◽  
Raman Lidar ◽  
Radiative Effects ◽  
Central Asian ◽  
Regional Sources ◽  
Lidar Measurements

Tajikistan is often affected by atmospheric mineral dust. The direct and indirect radiative effects of dust play a sensitive role in the climate system in Central Asia. The Central Asian Dust Experiment (CADEX) provides first lidar measurements in Tajikistan. The autonomous multiwavelength polarization Raman lidar PollyXT was operated for 1.5 years (2015/16) in Dushanbe. In spring, lofted layers of long-range transported dust and in summer/ autumn, lower laying dust from local or regional sources with large optical thicknesses occurred.

scholarly journals Long-term profiling of mineral dust and pollution aerosol with multiwavelength polarization/Raman lidar at the Central Asian site of Dushanbe, Tajikistan: Case studies

2017 ◽  
Author(s):  
Julian Hofer ◽  
Dietrich Althausen ◽  
Sabur F. Abdullaev ◽  
Abduvosit N. Makhmudov ◽  
Bakhron I. Nazarov ◽  
...  
Keyword(s):  
Middle Eastern ◽  
Asian Dust ◽  
Raman Lidar ◽  
Dust Event ◽  
Angstrom Exponent ◽  
Central Asian ◽  
Ångström Exponent ◽  
Lidar Ratio ◽  
532 Nm ◽  
Ångstrom Exponent

Abstract. For the first time, continuous vertically resolved aerosol measurements were performed by lidar in Tajikistan, Central Asia. Observations with the multiwavelength polarization/Raman lidar PollyXT were conducted during CADEX (Central Asian Dust EXperiment) in Dushanbe, Tajikistan, from March 2015 to August 2016. Co-located with the lidar a sun photometer was operated. The goal of CADEX is to provide an unprecedented data set on vertically resolved aerosol optical properties in Central Asia, an area highly affected by climate change but largely missing vertically resolved aerosol measurements. During the 18-months measurement campaign, mineral dust was detected frequently from ground to cirrus level height. In this study, an overview of the measurement period is given and four typical but different example measurement cases are discussed in detail. Three of them are dust cases and one is a contrasting pollution aerosol case. Vertical profiles of the measured optical properties and the calculated dust and non-dust mass concentrations are presented. Dust source regions were identified by means of backward trajectory analyses. A lofted layer of Middle Eastern dust with an aerosol optical thickness (AOT) of 0.4 and an extinction-related Ångström exponent of 0.41 was measured. In comparison, two near-ground dust cases have Central Asian sources. One is an extreme dust event with an AOT of 1.5 and Ångström exponent of 0.12 and the other one is a most extreme dust event with an AOT of above 4 (measured by sun photometer) and an Ångström exponent of −0.08. The observed lidar ratios (particle linear depolarization ratios) in the presented dust cases range from 40.3 sr to 46.9 sr (0.18–0.29) at 355 nm and from 35.7 sr to 42.9 sr (0.31–0.35) at 532 nm wavelength. The particle linear depolarization ratios indicate almost unpolluted dust in the case of a lofted dust layer and pure dust in the near-ground dust cases. The lidar ratio values are lower than typical lidar ratio values for Saharan dust (50–60 sr) and comparable to Middle Eastern/West-Asian dust lidar ratios (35–45 sr). In contrast, the presented case of pollution aerosol of local origin has an Ångström exponent of 2.07 and a lidar ratio (particle linear depolarization ratio) of 55.8 sr (0.03) at 355 nm and 32.8 sr (0.08) at 532 nm wavelength.

scholarly journals Towards continuous monitoring of aerosol hygroscopicity by Raman lidar measurements at the EARLINET station of Payerne

2019 ◽  
Author(s):  
Francisco Navas Guzmán ◽  
Giovanni Martucci ◽  
Martine Collaud Coen ◽  
María José Granados Muñoz ◽  
Maxime Hervo ◽  
...  
Keyword(s):  
Continuous Monitoring ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Lidar System ◽  
Remote Sensing Technique ◽  
Accuracy And Precision ◽  
Lidar Measurements ◽  
Constant Altitude ◽  
Aerosol Backscatter ◽  
Aerosol Hygroscopicity

Abstract. This study focuses on the analysis of aerosol hygroscopicity using remote sensing technique. Continuous observations of aerosol backscatter coefficient, temperature and water vapour mixing ratio are performed by means of a Raman lidar system at the aerological station of MeteoSwiss at Payerne (Switzerland) since 2008. These measurements allow us to monitor in a continuous way any change of aerosol properties as a function of the relative humidity (RH). These changes can be observed either in time at constant altitude or in altitude at a constant time. The accuracy and precision of RH measurements from the lidar have been evaluated using the radiosonde (RS) technique as reference. A total of 172 RSs were used in this intercomparison which revealed a small bias (

scholarly journals Multi-wavelength Raman lidar, sunphotometric and aircraft measurements in combination with inversion models for the estimation of the aerosol optical and physico-chemical properties over Athens, Greece

2012 ◽  
Vol 5 (1) ◽  
pp. 589-625
Author(s):  
R. E. Mamouri ◽  
A. Papayannis ◽  
V. Amiridis ◽  
D. Müller ◽  
P. Kokkalis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Chemical Properties ◽  
Urban Site ◽  
Aircraft Measurements ◽  
Raman Lidar ◽  
Lidar System ◽  
Aerosol Composition ◽  
Microphysical Properties ◽  
Multi Wavelength

Abstract. A novel procedure has been developed to retrieve, simultaneously, the optical, microphysical and chemical properties of tropospheric aerosols with a multi-wavelength Raman lidar system in the troposphere over an urban site (Athens, Greece: 37.9° N, 23.6° E, 200 m a.s.l.) using data obtained during the European Space Agency (ESA) THERMOPOLIS project which took place between 15–31 July 2009 over the Greater Athens Area (GAA). We selected to apply our procedure for a case study of intense aerosol layers occurred on 20–21 July 2009. The National Technical University of Athens (NTUA) EOLE 6-wavelength Raman lidar system has been used to provide the vertical profiles of the optical properties of aerosols (extinction and backscatter coefficients, lidar ratio) and the water vapor mixing ratio. An inversion algorithm was used to derive the mean aerosol microphysical properties (mean effective radius – reff), single-scattering albedo (ω) and mean complex refractive index (m) at selected heights in the 2–3 km height region. We found that reff was 0.3–0.4 μm, ω at 532 nm ranged from 0.63 to 0.88 and m ranged from 1.45 + 0.015i to 1.56 + 0.05i, in good accordance with in situ aircraft measurements. The final data set of the aerosol microphysical properties along with the water vapor and temperature profiles were incorporated into the ISORROPIA model to infer an in situ aerosol composition consistent with the retrieved m and ω values. The retrieved aerosol chemical composition in the 2–3 km height region gave a variable range of sulfate (0–60%) and organic carbon (OC) content (0–50%), although the OC content increased (up to 50%) and the sulfate content dropped (up to 30%) around 3 km height; in connection with the retrieved low ω value (0.63), indicates the presence of absorbing biomass burning smoke mixed with urban haze. Finally, the retrieved aerosol microphysical properties were compared with column-integrated sunphotometer data.

Dual-field-of-view Raman lidar measurements for the retrieval of cloud microphysical properties

2013 ◽  
Vol 52 (11) ◽  
pp. 2235 ◽  
Author(s):  
Jörg Schmidt ◽  
Ulla Wandinger ◽  
Aleksey Malinka
Keyword(s):  
Field Of View ◽  
Raman Lidar ◽  
Microphysical Properties ◽  
Lidar Measurements

scholarly journals UV Raman lidar measurements of relative humidity for the characterization of cirrus cloud microphysical properties

2009 ◽  
Vol 9 (22) ◽  
pp. 8799-8811 ◽  
Author(s):  
P. Di Girolamo ◽  
D. Summa ◽  
R.-F. Lin ◽  
T. Maestri ◽  
R. Rizzi ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Cloud Model ◽  
Cirrus Clouds ◽  
Cloud Layer ◽  
Cirrus Cloud ◽  
Raman Lidar ◽  
Heating Rates ◽  
Night Time ◽  
Microphysical Properties ◽  
Lidar Measurements

Abstract. Raman lidar measurements performed in Potenza by the Raman lidar system BASIL in the presence of cirrus clouds are discussed. Measurements were performed on 6 September 2004 in the frame of the Italian phase of the EAQUATE Experiment. The major feature of BASIL is represented by its capability to perform high-resolution and accurate measurements of atmospheric temperature and water vapour, and consequently relative humidity, both in daytime and night-time, based on the application of the rotational and vibrational Raman lidar techniques in the UV. BASIL is also capable to provide measurements of the particle backscatter and extinction coefficient, and consequently lidar ratio (at the time of these measurements, only at one wavelength), which are fundamental to infer geometrical and microphysical properties of clouds. A case study is discussed in order to assess the capability of Raman lidars to measure humidity in presence of cirrus clouds, both below and inside the cloud. While air inside the cloud layers is observed to be always under-saturated with respect to water, both ice super-saturation and under-saturation conditions are found inside these clouds. Upper tropospheric moistening is observed below the lower cloud layer. The synergic use of the data derived from the ground based Raman Lidar and of spectral radiances measured by the NAST-I Airborne Spectrometer allows the determination of the temporal evolution of the atmospheric cooling/heating rates due to the presence of the cirrus cloud. Lidar measurements beneath the cirrus cloud layer have been interpreted using a 1-D cirrus cloud model with explicit microphysics. The 1-D simulations indicate that sedimentation-moistening has contributed significantly to the moist anomaly, but other mechanisms are also contributing. This result supports the hypothesis that the observed mid-tropospheric humidification is a real feature which is strongly influenced by the sublimation of precipitating ice crystals. Results illustrated in this study demonstrate that Raman lidars, like the one used in this study, can resolve the spatial and temporal scales required for the study of cirrus cloud microphysical processes and appear sensitive enough to reveal and quantify upper tropospheric humidification associated with cirrus cloud sublimation.

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