Stratospheric dust collection by DUSTER (Dust in The Upper Stratosphere Tracking Experiment and Retrieval), a balloon-borne instrument, and laboratory analyses of collected dust.
Ciucci, Alessandra (2010) Stratospheric dust collection by DUSTER (Dust in The Upper Stratosphere Tracking Experiment and Retrieval), a balloon-borne instrument, and laboratory analyses of collected dust. [Tesi di dottorato] (Inedito)
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The subject of this work is focused on the study of stratospheric dust with DUSTER (Dust in the Upper Stratosphere Tracking Experiment and Retrieval) a balloon-borne instrument. The stratospheric environment is an atmospheric layer placed in the range altitude 20-50 km. The stratosphere is composed of aerosols and refractory dust of different nature: natural terrestrial dust, anthropogenic dust, and natural extraterrestrial dust. The DUSTER project is aimed at uncontaminated collection of stratospheric dust particles, in the submicron/micron range. The submicron/micron size range was chosen because: 1) it is poorly studied so far; 2) particles of natural terrestrial origin in this size range are responsible of local and global climate changing; 3) particles of natural extraterrestrial origin in submicron/micron range suffer less the heating due to the entry in the Earth atmosphere and subsequently they are less altered in the original physico-chemical characteristics. The DUSTER scientific aim is to derive the size distribution, the concentration and the composition of stratospheric dust, to study the natural and the extraterrestrial component. To reach its aim DUSTER implies in-situ collection and sample recovering to perform laboratory analyses without sample manipulation. The technical requirement of the instrument are: capability to work autonomously during the balloon flight in the range altitude of 30 – 40 km; capability to work at temperatures in the range -40°C < T < 80°C and pressure in the range 3 – 10 mbar; sampling at least 20 m3 of air for at least 24 h of continuous working; samples storage and retrieval under contamination controlled conditions (see Chapter 2 for more details). The particles are captured based on the principle of inertial impact collection (without the use of sticking materials) by a continuous flow created through the chamber. DUSTER had a qualification flight in January 2006 from Kiruna (Sweden) and two scientific flights from Svalbard (Norway) in June 2008 and July 2009. This work is a report of the two scientific flights from the sample holder preparation to the analyses of collected samples. In particular, it will deal with: - the sample holders structure, how to assemble them and their implementation for DUSTER 2009 campaign; -the instrument characteristics for DUSTER 2008 campaign and the improvements for DUSTER 2009 campaign; - the curation, to ensure the contamination control, and the characterization of the sample holders, to identify the particles actually collected from the spurious contamination; - the techniques used to characterize the sample holder before and after the flights and to analyze the sample collected; - the procedure to recognize the collected particles from the spurious contamination; - the sources of contamination due to the environment and to the sample holders materials; - the data reduction of the analyses performed on samples collected during DUSTER 2008 campaign; - a very preliminary analysis to identify particles collected during DUSTER 2009 campaign. The strength of DUSTER is to collect particles in a boundary layer in which could be found particles coming from extraterrestrial (e.g. interplanetary dust particles) and terrestrial environment (e.g. volcanic ash) mixed in an environment clean by human pollution.
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