OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY
Aerosols are ubiquitous in the troposphere and influence the global climate by changing the radiative properties of the atmosphere: directly, through the scattering and absorption of solar and terrestrial radiation, and indirectly acting as cloud condensation and ice nuclei formation. Although exten...
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Università degli Studi di Milano
2022
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ftunivmilanoair:oai:air.unimi.it:2434/916834 2024-02-11T09:57:10+01:00 OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY RAVASIO, CLAUDIA tutor: Potenza Marco Alberto Carlo co-tutor: B. Delmonte director of the school: M. Paris C. Ravasio POTENZA, MARCO ALBERTO CARLO PARIS, MATTEO 2022-03-22 http://hdl.handle.net/2434/916834 eng eng Università degli Studi di Milano http://hdl.handle.net/2434/916834 info:eu-repo/semantics/openAccess Digital holography aerosol mineral dust ice core optical properties Settore FIS/03 - Fisica della Materia info:eu-repo/semantics/doctoralThesis 2022 ftunivmilanoair 2024-01-16T23:35:41Z Aerosols are ubiquitous in the troposphere and influence the global climate by changing the radiative properties of the atmosphere: directly, through the scattering and absorption of solar and terrestrial radiation, and indirectly acting as cloud condensation and ice nuclei formation. Although extensive research has been carried out on this topic, significant uncertainties still affect current estimates of this contribution on the Earth’s energy balance. In this work, I studied the effects of the particle shape on the optical parameters for the radiative transfer through the atmosphere. I present the results of the characterization of mineral dust and micrometric particles transported and subsequently deposited on the surface of glaciers, and in time brought deeper, layer after layer. To this end, digital microscopic holography has proven to be an excellent suite for distinguishing non-spherical particles, going beyond the common spherical approximation. From the interference between the trans-illuminating reference field and the diffracted light by the particles in the forward direction, the cross-sectional area and the extinction cross-section can be numerically retrieved, thus providing a multi-parametric single-particle approach. This work develops a formal description of the technique through the theory of image formation in holographic microscopy, reporting a suite of validation measurements with calibrated particles, and providing an overview of the experimental results from Antarctic and Alpine snow and ice cores. The analysis reveals a remarkable variability in the extinction cross-section of the particles depending on their shape, with a prevalence of non-spherical particles, which proves the importance of measuring morphological and optical properties simultaneously. I also observed a prevalence of fine particles (< 2 μm in size), with the occurrence of aggregates and some giant particles (> 10 μm in size), especially in Alpine snow cores. Currently, global and regional models assume dust ... Doctoral or Postdoctoral Thesis Antarc* Antarctic ice core The University of Milan: Archivio Istituzionale della Ricerca (AIR) Antarctic |
institution |
Open Polar |
collection |
The University of Milan: Archivio Istituzionale della Ricerca (AIR) |
op_collection_id |
ftunivmilanoair |
language |
English |
topic |
Digital holography aerosol mineral dust ice core optical properties Settore FIS/03 - Fisica della Materia |
spellingShingle |
Digital holography aerosol mineral dust ice core optical properties Settore FIS/03 - Fisica della Materia RAVASIO, CLAUDIA OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY |
topic_facet |
Digital holography aerosol mineral dust ice core optical properties Settore FIS/03 - Fisica della Materia |
description |
Aerosols are ubiquitous in the troposphere and influence the global climate by changing the radiative properties of the atmosphere: directly, through the scattering and absorption of solar and terrestrial radiation, and indirectly acting as cloud condensation and ice nuclei formation. Although extensive research has been carried out on this topic, significant uncertainties still affect current estimates of this contribution on the Earth’s energy balance. In this work, I studied the effects of the particle shape on the optical parameters for the radiative transfer through the atmosphere. I present the results of the characterization of mineral dust and micrometric particles transported and subsequently deposited on the surface of glaciers, and in time brought deeper, layer after layer. To this end, digital microscopic holography has proven to be an excellent suite for distinguishing non-spherical particles, going beyond the common spherical approximation. From the interference between the trans-illuminating reference field and the diffracted light by the particles in the forward direction, the cross-sectional area and the extinction cross-section can be numerically retrieved, thus providing a multi-parametric single-particle approach. This work develops a formal description of the technique through the theory of image formation in holographic microscopy, reporting a suite of validation measurements with calibrated particles, and providing an overview of the experimental results from Antarctic and Alpine snow and ice cores. The analysis reveals a remarkable variability in the extinction cross-section of the particles depending on their shape, with a prevalence of non-spherical particles, which proves the importance of measuring morphological and optical properties simultaneously. I also observed a prevalence of fine particles (< 2 μm in size), with the occurrence of aggregates and some giant particles (> 10 μm in size), especially in Alpine snow cores. Currently, global and regional models assume dust ... |
author2 |
tutor: Potenza Marco Alberto Carlo co-tutor: B. Delmonte director of the school: M. Paris C. Ravasio POTENZA, MARCO ALBERTO CARLO PARIS, MATTEO |
format |
Doctoral or Postdoctoral Thesis |
author |
RAVASIO, CLAUDIA |
author_facet |
RAVASIO, CLAUDIA |
author_sort |
RAVASIO, CLAUDIA |
title |
OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY |
title_short |
OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY |
title_full |
OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY |
title_fullStr |
OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY |
title_full_unstemmed |
OPTICAL CHARACTERIZATION OF MINERAL DUST CONTENT IN SNOW AND ICE CORES WITH DIGITAL IN-LINE HOLOGRAPHY |
title_sort |
optical characterization of mineral dust content in snow and ice cores with digital in-line holography |
publisher |
Università degli Studi di Milano |
publishDate |
2022 |
url |
http://hdl.handle.net/2434/916834 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic ice core |
genre_facet |
Antarc* Antarctic ice core |
op_relation |
http://hdl.handle.net/2434/916834 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1790609141263237120 |