A novel approach for the characterization of transport and optical properties of aerosol particles near sources – Part I: Measurement of particle backscatter coefficient maps with a scanning UV lidar

Clouds in the tropics have an important role in the energy budget, atmospheric circulation, humidity, and composition of the tropical-to-global upper-troposphere–lower-stratosphere. Due to its non-sun-synchronous orbit, the Cloud–Aerosol Transport System (CATS) onboard the International Space Station (ISS) provided novel information on clouds from space in terms of overpass time in the period of 2015–2017. In this paper, we provide a seasonally resolved comparison of CATS characterization of high clouds (between 13 and 18 km altitude) in the tropics with well-established CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation) data, both in terms of clouds’ occurrence and cloud optical properties (optical depth). Despite the fact that cloud statistics for CATS and CALIOP are generated using intrinsically different local overpass times, the characterization of high clouds occurrence and optical properties in the tropics with the two instruments is very similar. Observations from CATS underestimate clouds occurrence (up to 80%, at 18 km) and overestimate the occurrence of very thick clouds (up to 100% for optically very thick clouds, at 18 km) at higher altitudes. Thus, the description of stratospheric overshoots with CATS and CALIOP might be different. While this study hints at the consistency of CATS and CALIOP clouds characterizaton, the small differences highlighted in this work should be taken into account when using CATS for estimating cloud properties and their variability in the tropics.

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Methods for characterization of organic compounds in atmospheric aerosol particles

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-014-8394-3 ◽

2014 ◽

Vol 407 (20) ◽

pp. 5877-5897 ◽

Cited By ~ 15

Author(s):

Jevgeni Parshintsev ◽

Tuulia Hyötyläinen

Keyword(s):

Organic Compounds ◽

Atmospheric Aerosol ◽

Aerosol Particles ◽

Atmospheric Aerosol Particles

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Application of Innovative TGA/Chemometric Approach for Forensic Purposes: The Estimation of the Time since Death in Contaminated Specimens

Diagnostics ◽

10.3390/diagnostics11010121 ◽

2021 ◽

Vol 11 (1) ◽

pp. 121

Author(s):

Roberta Risoluti ◽

Giuseppina Gullifa ◽

Vittorio Fineschi ◽

Paola Frati ◽

Stefano Materazzi

Keyword(s):

Multidisciplinary Approach ◽

Vitreous Humor ◽

Classification Model ◽

Forensic Sciences ◽

Time Since Death ◽

Time Of Death ◽

Novel Approach ◽

Chemometric Approach ◽

Postmortem Examinations

Chronothanatology has always been a challenge in forensic sciences. Therefore, the importance of a multidisciplinary approach for the characterization of matrices (organs, tissues, or fluids) that respond linearly to the postmortem interval (PMI) is emerging increasingly. The vitreous humor is particularly suitable for studies aimed at assessing time-related modifications because it is topographically isolated and well-protected. In this work, a novel approach based on thermogravimetry and chemometrics was used to estimate the time since death in the vitreous humor and to collect a databank of samples derived from postmortem examinations after medico–legal evaluation. In this study, contaminated and uncontaminated specimens with tissue fragments were included in order to develop a classification model to predict time of death based on partial least squares discriminant analysis (PLS-DA) that was as robust as possible. Results demonstrate the possibility to correctly predict the PMI even in contaminated samples, with an accuracy not lower than 70%. In addition, the correlation coefficient of the measured versus predicted outcomes was found to be 0.9978, confirming the ability of the model to extend its feasibility even to such situations involving contaminated vitreous humor.

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