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Accueil du site → Doctorat → Grèce → Estimates of the vertical distribution of desert dust and condensation nuclei over the Mediterranean, with the synergistic use of active and passive remote sensing techniques

Aristotle University of Thessaloniki (2017)

Estimates of the vertical distribution of desert dust and condensation nuclei over the Mediterranean, with the synergistic use of active and passive remote sensing techniques

Μαρίνου Ελένη Ι.

Titre : Estimates of the vertical distribution of desert dust and condensation nuclei over the Mediterranean, with the synergistic use of active and passive remote sensing techniques

Εκτίμηση της κατακόρυφης κατανομής της ερημικής σκόνης και των πυρήνων συμπύκνωσης στη Μεσόγειο με τη συνέργεια μεθόδων ενεργής και παθητικής τηλεπισκόπησης

Auteur : Μαρίνου Ελένη Ι.

Etablissement de soutenance : Aristotle University of Thessaloniki

Grade : Doctor of Philosophy (PhD) 2017

Résumé
The overarching goal of this thesis is to fill existing gaps in our understanding on the role of desert dust in climatic parameters over the Mediterranean by using advanced remote sensing methods and synergies. In line with this, desert dust was discriminated from total aerosol obser-vations provided by modern space-based remote sensors. The 3-dimentional distribution of the mineral dust loads over the Mediterranean and North Africa was investigated in order to provide critical input for the radiative impact from natural sources. Finally, dust-related climatologies of ice nucleating particle concentrations were produced to study the impact of desert dust on cloud formation. Our approach involves the utilization of passive and active remote sensing synergies, placing emphasis on the essential vertically-resolved aerosol information provided by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission. First, a pure dust product is derived from CALIPSO measurements, following sophisticated methodologies devel-oped in the framework of the European Aerosol Research Lidar Network (EARLINET). The discrimination of dust from other aerosol types uses the profiles of backscatter coefficient and depolarization ratio of CALIPSO, along with ground-based measurements and methods from EARLINET. The pure dust product is evaluated against measurements from the AErosol RO-botic NETwork (AERONET) and compared with observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and vertical profiles of the BSC-DREAM8b model (Bar-celona Supercomputer Center - Dust Regional Atmospheric Model). Progressing further, the dust product is used to provide a 3D multiyear analysis on the evolu-tion of Saharan dust over North Africa and Europe, based on a nine-year CALIPSO dataset (2007-2015). The results reveal the 3D dust evolution and the seasonal patterns of dust over its transportation paths from the Sahara towards the Mediterranean and Continental Europe. The product has found various application regarding synergies with passive sensors but also in the domain of model/satellite evaluation. Three application examples are presented, concerning (a) the optimization of dust transport model representations in order to understand the severe dust storm over the Middle East and the Eastern Mediterranean in 2015, (b) the development of advanced methodologies for aerosol typing from space contributing on the attempts to discrimi-nate anthropogenic from natural aerosols, and (c) the evaluation of different dust parameteriza-tions in order to represent the dust cycle in regional climate models. Finally, the dust product is used to retrieve dust-related Ice Nuclei concentration vertical dis-tributions over the Mediterranean. This result provides a unique opportunity to identify the gaps in our knowledge regarding heterogeneous ice formation when combined with cloud observa-tions in the future.

Mots clés : Atmospheric aerosols, Dust, Particles, Ice nuclei, Ατμοσφαιρικά αερολύματα, Σκόνη, Σωμάτια, Πυρήνες παγοποίησης

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