Detection and classification of atmospheric aerosols using multi-wavelength CO 2 lidar

2007 ◽  
Author(s):  
Russell E. Warren ◽  
Richard G. Vanderbeek
Keyword(s):  
Atmospheric Aerosols ◽  
Multi Wavelength

Detection and classification of atmospheric aerosols using multi-wavelength LWIR LIDAR

2009 ◽  
Author(s):  
Russell E. Warren ◽  
Richard G. Vanderbeek ◽  
Jeffrey L. Ahl
Keyword(s):  
Atmospheric Aerosols ◽  
Multi Wavelength

Multi-wavelength optical determination of black and brown carbon in atmospheric aerosols

2015 ◽  
Vol 108 ◽  
pp. 1-12 ◽  
Author(s):  
D. Massabò ◽  
L. Caponi ◽  
V. Bernardoni ◽  
M.C. Bove ◽  
P. Brotto ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Brown Carbon ◽  
Multi Wavelength ◽  
Optical Determination

scholarly journals Two-wavelength thermal–optical determination of light-absorbing carbon in atmospheric aerosols

2019 ◽  
Vol 12 (6) ◽  
pp. 3173-3182 ◽  
Author(s):  
Dario Massabò ◽  
Alessandro Altomari ◽  
Virginia Vernocchi ◽  
Paolo Prati
Keyword(s):  
Laser Diode ◽  
Atmospheric Aerosols ◽  
Direct Determination ◽  
Optical Transmittance ◽  
Carbonaceous Aerosol ◽  
Electromagnetic Spectrum ◽  
Multi Wavelength ◽  
Physics Department ◽  
The University

Abstract. Thermal–optical analysis is widely adopted for the quantitative determination of total (TC), organic (OC), and elemental (EC) carbon in atmospheric aerosol sampled by suitable filters. Nevertheless, the methodology suffers from several uncertainties and artifacts such as the well-known issue of charring affecting the OC–EC separation. In the standard approach, the effect of the possible presence of brown carbon, BrC, in the sample is neglected. BrC is a fraction of OC, usually produced by biomass burning with a thermic behavior intermediate between OC and EC. BrC is optically active: it shows an increasing absorbance when the wavelength moves to the blue–UV region of the electromagnetic spectrum. Definitively, the thermal–optical characterization of carbonaceous aerosol should be reconsidered to address the possible BrC content in the sample under analysis. We introduce here a modified Sunset Lab Inc. EC–OC analyzer. Starting from a standard commercial instrument, the unit has been modified at the physics department of the University of Genoa (Italy), making possible the alternative use of the standard laser diode at λ=635 nm and of a new laser diode at λ=405 nm. In this way, the optical transmittance through the sample can be monitored at both wavelengths. Since at shorter wavelengths the BrC absorbance is higher, a better sensitivity to this species is gained. The modified instrument also gives the possibility to quantify the BrC concentration in the sample at both wavelengths. The new unit has been thoroughly tested, with both artificial and real-world aerosol samples: the first experiment, in conjunction with the multi-wavelength absorbance analyzer (MWAA; Massabò et al., 2013, 2015), resulted in the first direct determination of the BrC mass absorption coefficient (MAC) at λ=405 nm: MAC =23±1 m2 g−1.

scholarly journals MULTI-WAVELENGTH OBSERVATIONS OF SUPERNOVA 2011ei: TIME-DEPENDENT CLASSIFICATION OF TYPE IIb AND Ib SUPERNOVAE AND IMPLICATIONS FOR THEIR PROGENITORS

2013 ◽  
Vol 767 (1) ◽  
pp. 71 ◽  
Author(s):  
Dan Milisavljevic ◽  
Raffaella Margutti ◽  
Alicia M. Soderberg ◽  
Giuliano Pignata ◽  
Laura Chomiuk ◽  
...  
Keyword(s):  
Time Dependent ◽  
Multi Wavelength

scholarly journals Spectral Energy Distributions of a set of H ii regions in M33 (HerM33es)

2011 ◽  
Vol 7 (S284) ◽  
pp. 122-124
Author(s):  
Monica Relaño ◽  
Simon Verley ◽  
Isabel Pérez ◽  
Carsten Kramer ◽  
Manolis Xilouris ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Morphological Type ◽  
Spectral Energy ◽  
H Ii Regions ◽  
Energy Distributions ◽  
Stellar Cluster ◽  
Multi Wavelength ◽  
Hα Emission ◽  
Group Galaxy

AbstractWithin the framework of the HerM33es Key Project for Herschel and in combination with multi-wavelength data, we study the Spectral Energy Distribution (SED) of a set of H ii regions in the Local Group Galaxy M33. Using the Hα emission, we perform a classification of a selected H ii region sample in terms of morphology, separating the objects in filled, mixed, shell and clear shell objects. We obtain the SED for each H ii region as well as a representative SED for each class of objects. We also study the emission distribution of each band within the regions. We find different trends in the SEDs for each morphological type that are related to properties of the dust and their associated stellar cluster. The emission distribution of each band within the region is different for each morphological type of object.

scholarly journals Classification of Astrophysics Journal Articles with Machine Learning to Identify Data for NED

2022 ◽  
Vol 134 (1031) ◽  
pp. 014501
Author(s):  
Tracy X. Chen ◽  
Rick Ebert ◽  
Joseph M. Mazzarella ◽  
Cren Frayer ◽  
Scott Terek ◽  
...  
Keyword(s):  
Machine Learning ◽  
Journal Article ◽  
Value Added ◽  
Journal Articles ◽  
Online Service ◽  
Production Pipeline ◽  
Multi Wavelength ◽  
Data Content ◽  
Number Of Publications

Abstract The NASA/IPAC Extragalactic Database (NED) is a comprehensive online service that combines fundamental multi-wavelength information for known objects beyond the Milky Way and provides value-added, derived quantities and tools to search and access the data. The contents and relationships between measurements in the database are continuously augmented and revised to stay current with astrophysics literature and new sky surveys. The conventional process of distilling and extracting data from the literature involves human experts to review the journal articles and determine if an article is of extragalactic nature, and if so, what types of data it contains. This is both labor intensive and unsustainable, especially given the ever-increasing number of publications each year. We present here a machine learning (ML) approach developed and integrated into the NED production pipeline to help automate the classification of journal article topics and their data content for inclusion into NED. We show that this ML application can successfully reproduce the classifications of a human expert to an accuracy of over 90% in a fraction of the time it takes a human, allowing us to focus human expertise on tasks that are more difficult to automate.

scholarly journals Aerosol optical properties as observed from an ultralight aircraft over the Strait of Gibraltar

2020 ◽  
Vol 13 (8) ◽  
pp. 4461-4477 ◽  
Author(s):  
Patrick Chazette
Keyword(s):  
Optical Properties ◽  
Atmospheric Aerosols ◽  
Transport Processes ◽  
Horizontal Line ◽  
Free Troposphere ◽  
Strait Of Gibraltar ◽  
North East ◽  
San Pedro ◽  
The Difference

Abstract. An unprecedented scientific flight was conducted over the Strait of Gibraltar to study the optical properties of the atmospheric aerosols from the sea surface to the lower free troposphere within the framework of the southern Spain experiment for spaceborne mission validation (SUSIE). A Rayleigh–Mie lidar was installed on an ultralight aircraft (ULA) for vertical (nadir) and horizontal line-of-sight measurements. This experiment took place on 13 August 2011 in parallel with continuous observations with a N2-Raman lidar from the coastal site of San Pedro Alcantara (∼ 50 km north-east of Gibraltar). Significant differences were observed between the optical properties of the aerosol layers sampled over the Strait of Gibraltar and San Pedro Alcantara. These differences are related to the surface–atmosphere interface in the planetary boundary layer and the origins and transport processes in the lower free troposphere. A significant contribution of terrigenous aerosols originating from the Iberian Peninsula is highlighted over the two areas. These polluted dusts are identified with lidar ratios (LRs) ∼45±8 sr higher than those of Saharan aerosols sampled during the same period (<34 sr) at 355 nm. Furthermore, the particle depolarization ratio is derived with values of ∼ 10 %–15 % for the polluted dust and >20 % for the Saharan dusts. The difference in LRs is the opposite of what is usually assumed for these two types of aerosols and highlights the need to update the classification of aerosols in terms of LR to be used in the inversion of vertical profiles from future spaceborne missions embedding a lidar operating at 355 nm.

scholarly journals Ceilometer aerosol profiling versus Raman lidar in the frame of the INTERACT campaign of ACTRIS

2015 ◽  
Vol 8 (5) ◽  
pp. 2207-2223 ◽  
Author(s):  
F. Madonna ◽  
F. Amato ◽  
J. Vande Hey ◽  
G. Pappalardo
Keyword(s):  
Atmospheric Aerosols ◽  
Signal To Noise Ratio ◽  
Cloud Base ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Strong Motivation ◽  
Technological Improvements ◽  
Aerosol Properties

Abstract. Despite their differences from more advanced and more powerful lidars, the low construction and operation cost of ceilometers (originally designed for cloud base height monitoring) has fostered their use for the quantitative study of aerosol properties. The large number of ceilometers available worldwide represents a strong motivation to investigate both the extent to which they can be used to fill in the geographical gaps between advanced lidar stations and also how their continuous data flow can be linked to existing networks of the more advanced lidars, like EARLINET (European Aerosol Research Lidar Network). In this paper, multi-wavelength Raman lidar measurements are used to investigate the capability of ceilometers to provide reliable information about atmospheric aerosol properties through the INTERACT (INTERcomparison of Aerosol and Cloud Tracking) campaign carried out at the CNR-IMAA Atmospheric Observatory (760 m a.s.l., 40.60° N, 15.72° E), in the framework of the ACTRIS (Aerosol Clouds Trace gases Research InfraStructure) FP7 project. This work is the first time that three different commercial ceilometers with an advanced Raman lidar are compared over a period of 6 months. The comparison of the attenuated backscatter coefficient profiles from a multi-wavelength Raman lidar and three ceilometers (CHM15k, CS135s, CT25K) reveals differences due to the expected discrepancy in the signal to noise ratio (SNR) but also due to changes in the ambient temperature on the short and mid-term stability of ceilometer calibration. Therefore, technological improvements are needed to move ceilometers towards operational use in the monitoring of atmospheric aerosols in the low and free troposphere.

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