scholarly journals Combined use of Mie–Raman and fluorescence lidar observations for improving aerosol characterization: feasibility experiment

2020 ◽  
Vol 13 (12) ◽  
pp. 6691-6701
Author(s):  
Igor Veselovskii ◽  
Qiaoyun Hu ◽  
Philippe Goloub ◽  
Thierry Podvin ◽  
Mikhail Korenskiy ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Interference Filter ◽  
Dust Particles ◽  
Raman Lidar ◽  
Fluorescence Measurements ◽  
Combined Use ◽  
Wide Range ◽  
Elastic Backscattering ◽  
Lidar Observations ◽  
Aerosol Characterization

Abstract. To study the feasibility of a fluorescence lidar for aerosol characterization, the fluorescence channel is added to the LILAS multiwavelength Mie–Raman lidar of Lille University, France. A part of the fluorescence spectrum induced by 355 nm laser radiation is selected by the interference filter of 44 nm bandwidth centered at 466 nm. Such an approach has proved to have high sensitivity, allowing fluorescence signals from weak aerosol layers to be detected and the fluorescence backscattering coefficient from the ratio of fluorescence and nitrogen Raman backscatters to be calculated. Observations were performed during the November 2019–February 2020 period. The fluorescence capacity (ratio of fluorescence to elastic backscattering coefficients), measured under conditions of low relative humidity, varied in a wide range, being the highest for the smoke and the lowest for the dust particles. The results presented also demonstrate that the fluorescence measurements can be used for monitoring the aerosol inside the cloud layers.

scholarly journals Combined use of Mie-Raman and fluorescence lidar observations for improving aerosol characterization: feasibility experiment

2020 ◽  
Author(s):  
Igor Veselovskii ◽  
Qiaoyun Hu ◽  
Philippe Goloub ◽  
Thierry Podvin ◽  
Mikhail Korenskiy ◽  
...  
Keyword(s):  
Simultaneous Detection ◽  
High Sensitivity ◽  
Dust Particles ◽  
Fluorescence Signal ◽  
Aerosol Layer ◽  
Hygroscopic Growth ◽  
Backscattering Coefficient ◽  
Wide Range ◽  
Elastic Backscattering ◽  
Aerosol Characterization

Abstract. To study the feasibility of a fluorescence lidar for aerosol characterization, the fluorescence channel is added to LILAS – multiwavelength Mie-Raman lidar of Lille University, France. A part of fluorescence spectrum is selected by the interference filter of 44 nm bandwidth centered at 466 nm. Such an approach has demonstrated high sensitivity, allowing to detect fluorescence signal from weak aerosol layers (backscattering coefficient at 1064 nm is below 0.02 Mm−1 sr−1) up to a height of 5000 m. Simultaneous detection of nitrogen Raman and fluorescence backscatters allows to quantify the fluorescence backscattering coefficient. Observations were performed during November 2019–February 2020 period. The fluorescence capacity (ratio of fluorescence to elastic backscattering coefficients) varied in a wide range, being the highest for the smoke and the lowest for the dust particles. The fluorescence capacity depends as well strongly on the relative humidity, because the water uptake at the condition of high RH increases the elastic backscattering, without significant modification of the fluorescence. Thus, simultaneous measurements of Mie-Raman and fluorescence lidars open opportunity for the study of the particle hygroscopic growth. The fluorescence technique can be used also for monitoring the aerosol inside the cloud layers. The results presented demonstrate, that aerosol and cloud particles can be mixed both externally and internally. When the cloud is formed at the top or inside the aerosol layer (such scenario can be probably considered as internal mixing) we observed significant (up to factor 5) increase of fluorescence backscattering. Among possible mechanisms of such enhancement we can assume modification of the scattering phase function of the particles embedded in the water microspheres and the lens effect due to the water shell presence.

scholarly journals From the Caribbean to West Africa: Four weeks of continuous dust and marine aerosol profiling with shipborne polarization/Raman lidar – a contribution to SALTRACE

2017 ◽  
Author(s):  
Franziska Rittmeister ◽  
Albert Ansmann ◽  
Ronny Engelmann ◽  
Annett Skupin ◽  
Holger Baars ◽  
...  
Keyword(s):  
Long Range ◽  
Prediction Models ◽  
Saharan Dust ◽  
Dust Particles ◽  
Research Vessel ◽  
Long Range Transport ◽  
Marine Aerosol ◽  
Raman Lidar ◽  
Range Transport ◽  
Lidar Observations

Abstract. Continuous vertically resolved monitoring of marine aerosol, Saharan dust, and marine/dust aerosol mixtures was performed with multiwavelength polarization/Raman lidar aboard the German research vessel R/V Meteor during a one-month transatlantic cruise from Guadeloupe to Cabo Verde over 4500 km (from 61.5° W to 2&deg W, mostly along 14.5° N) in April–May 2013, as part of SALTRACE (Saharan Aerosol Long-range Transport and Aerosol–Cloud Interaction Experiment). An overview of measured aerosol optical properties over the tropical Atlantic is given in terms of spectrally resolved particle backscatter and extinction coefficients, lidar ratio, and linear depolarization ratio. Height profiles from the marine boundary layer (MBL) up to the top of the Saharan Air Layer (SAL) are presented. MBL and SAL mean lidar ratios were around 20 and 40 sr. These values indicate clean marine conditions in the MBL and entrainment of marine particles into the lower part of the SAL. In the central and upper parts of the SAL, the lidar ratios were most frequently 50–60 sr and thus typical for Saharan dust. The MBL and SAL mean depolarization ratios were close to 0.05 and between 0.2–0.3, respectively, which reflects almost dust-free conditions in the MBL and the occurrence of a mixture of marine and dust particles in the SAL. The conceptual model, describing the long-range transport and removal processes of Saharan dust over the North Atlantic, is discussed and confronted with the lidar observations along the west-to-east track of the slowly moving research vessel. The role of turbulent downward mixing as an efficient dust removal process is illuminated. In a follow-up article (Rittmeister et al., 2017), the lidar observations of dust extinction coefficient and derived mass concentration profiles are compared with respective dust profiles simulated with three well-established European atmospheric aerosol and dust prediction models (MACC, NMMB/BSC-Dust, SKIRON).

scholarly journals Evaluation of the Lidar/Radiometer Inversion Code (LIRIC) to determine microphysical properties of volcanic and desert dust

2013 ◽  
Vol 6 (1) ◽  
pp. 911-948 ◽  
Author(s):  
J. Wagner ◽  
A. Ansmann ◽  
U. Wandinger ◽  
P. Seifert ◽  
A. Schwarz ◽  
...  
Keyword(s):  
Theoretical Background ◽  
Saharan Dust ◽  
Dust Particles ◽  
Raman Lidar ◽  
Particle Volume ◽  
Microphysical Properties ◽  
Fine Mode ◽  
Lidar Ratio ◽  
Lidar Observations ◽  
Good Agreement

Abstract. The Lidar/Radiometer Inversion Code (LIRIC) combines the multiwavelength lidar technique with sun-sky photometry and allows us to retrieve vertical profiles of particle optical and microphysical properties, separately for fine-mode and coarse-mode particles. After a brief presentation of the theoretical background, we evaluate the potential of LIRIC to retrieve the optical and microphysical properties of irregularly shaped dust particles. The method is applied to two very different aerosol scenarios, a strong Saharan dust outbreak towards central Europe and an Eyjafjallajökull volcanic dust event. LIRIC profiles of particle volume and mass concentrations are compared with results obtained with the polarization-lidar-based POLIPHON method. LIRIC profiles of optical properties such as particle backscatter coefficients, lidar ratio, Ångström exponent, and particle depolarization ratio are compared with direct Raman lidar observations. Good agreement between the different results are found for most of the retrieval products.

scholarly journals Gold–Carbon Nanocomposites for Environmental Contaminant Sensing

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 719
Author(s):  
Shahrooz Rahmati ◽  
William Doherty ◽  
Arman Amani Babadi ◽  
Muhamad Syamim Akmal Che Mansor ◽  
Nurhidayatullaili Muhd Julkapli ◽  
...  
Keyword(s):  
Environmental Pollutants ◽  
High Sensitivity ◽  
Environmental Crisis ◽  
World Population ◽  
Chemical Contaminants ◽  
Carbon Nanocomposites ◽  
Minimal Sample ◽  
Wide Range ◽  
And Control ◽  
Analytical Tools

The environmental crisis, due to the rapid growth of the world population and globalisation, is a serious concern of this century. Nanoscience and nanotechnology play an important role in addressing a wide range of environmental issues with innovative and successful solutions. Identification and control of emerging chemical contaminants have received substantial interest in recent years. As a result, there is a need for reliable and rapid analytical tools capable of performing sample analysis with high sensitivity, broad selectivity, desired stability, and minimal sample handling for the detection, degradation, and removal of hazardous contaminants. In this review, various gold–carbon nanocomposites-based sensors/biosensors that have been developed thus far are explored. The electrochemical platforms, synthesis, diverse applications, and effective monitoring of environmental pollutants are investigated comparatively.

scholarly journals The Combined Usage of the Global Leadership Initiative on Malnutrition Criteria and Controlling Nutrition Status Score in Acute Care Hospitals

2021 ◽  
pp. 1-7
Author(s):  
Asako Mitani ◽  
Takahito Iwai ◽  
Toshiaki Shichinohe ◽  
Hiroshi Takeda ◽  
Satomi Kumagai ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Acute Care ◽  
Area Under The Curve ◽  
High Sensitivity ◽  
Acute Care Hospitals ◽  
Global Leadership ◽  
Nutrition Status ◽  
Nutritional Interventions ◽  
Combined Use ◽  
Conut Score

<b><i>Introduction:</i></b> The Global Leadership Initiative on Malnutrition (GLIM) lacks reliable blood tests for evaluating the nutrition status. We retrospectively compared the GLIM criteria, Controlling Nutrition Status (CONUT) score, and Subjective Global Assessment (SGA) to establish effective malnutrition screening and provide appropriate nutritional interventions according to severity. <b><i>Methods:</i></b> We classified 177 patients into 3 malnutrition categories (normal/mild, moderate, and severe) according to the GLIM criteria, CONUT score, and SGA. We investigated the malnutrition prevalence, concordance of malnutrition severity, predictability of clinical outcome, concordance by etiology, and clinical outcome by inflammation. <b><i>Results:</i></b> The highest prevalence of malnutrition was found using the GLIM criteria (87.6%). Concordance of malnutrition severity was low between the GLIM criteria and CONUT score. Concordance by etiology was low in all groups but was the highest in the “acute disease” group. The area under the curve of clinical outcome and that of the “with inflammation group” were significantly higher when using the CONUT score versus using the other tools (0.679 and 0.683, respectively). <b><i>Conclusion:</i></b> The GLIM criteria have high sensitivity, while the CONUT score can effectively predict the clinical outcome of malnutrition. Their combined use can efficiently screen for malnutrition and patient severity in acute care hospitals.

scholarly journals Pulsed Electromagnetic Cross-Well Exploration for Monitoring Permafrost and Examining the Processes of Its Geocryological Changes

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 60
Author(s):  
Viacheslav Glinskikh ◽  
Oleg Nechaev ◽  
Igor Mikhaylov ◽  
Kirill Danilovskiy ◽  
Vladimir Olenchenko
Keyword(s):  
High Performance ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Data Interpretation ◽  
Industrial Facilities ◽  
Wide Range ◽  
Vector Finite Element ◽  
A New Technique ◽  
Pulsed Electromagnetic

This paper is dedicated to the topical problem of examining permafrost’s state and the processes of its geocryological changes by means of geophysical methods. To monitor the cryolithozone, we proposed and scientifically substantiated a new technique of pulsed electromagnetic cross-well sounding. Based on the vector finite-element method, we created a mathematical model of the cross-well sounding process with a pulsed source in a three-dimensional spatially heterogeneous medium. A high-performance parallel computing algorithm was developed and verified. Through realistic geoelectric models of permafrost with a talik under a highway, constructed following the results of electrotomography field data interpretation, we numerically simulated the pulsed sounding on the computing resources of the Siberian Supercomputer Center of SB RAS. The simulation results suggest the proposed system of pulsed electromagnetic cross-well monitoring to be characterized by a high sensitivity to the presence and dimensions of the talik. The devised approach can be oriented to addressing a wide range of issues related to monitoring permafrost rocks under civil and industrial facilities, buildings, and constructions.

scholarly journals Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski
Keyword(s):  
Raman Spectroscopy ◽  
Cell Walls ◽  
Structural Changes ◽  
Spatial Information ◽  
Technological Development ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Plant Tissues ◽  
Wide Range ◽  
Identification Technique

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.

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