Examensarbeten för kandidatexamen // Bachelor Theses

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Browsar Examensarbeten för kandidatexamen // Bachelor Theses efter Ämnesord "Climate Research"

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    Analys av HCN-emission från kometen C/2013 R1 (Lovejoy)
    (2015) Olivefors, Astrid; Källström, Philip; Tegehall, Elin; Levinsson, Alexander; Chalmers tekniska högskola / Institutionen för rymd- och geovetenskap; Chalmers University of Technology / Department of Earth and Space Sciences
    In this report, results from the observations of comet C/2013 R1 (Lovejoy) carried out with the 20 meter telescope at Onsala Space Observatory during the autumn of 2013 are presented. The project comprises the analysis of data from the observation dates when emission from the rotational transition J = 1 0 for the molecule hydrogen cyanide (HCN) were observed. Detections have been made for seven different dates when C/2013 R1 (Lovejoy) were at a distance of 0.94-0.82AU from the sun, just before perihelion. The production rate increases from 31026 s1 to 51026 s1 with the decreasing distance to the sun. One of the days has also been divided in mean value formations over shorter time intervals for which a periodic variation in the production rate can be discerned although not confirmed. To perform calculations and processing of data, two computer programs have been used. The first is xs, a data reduction software for radio astronomical observations, written by Per Bergman at Onsala Space Observatory. The second program is mom, developed by Stefanie Milam at NASA Goddard Space Flight Center. iv
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    Att studera askmoln med GNSS
    (2014) Nguyen, Björnborg; Sjöberg, Mattias; Chalmers tekniska högskola / Institutionen för rymd- och geovetenskap; Chalmers University of Technology / Department of Earth and Space Sciences
    Abstract In this report the technique of observing volcanic ash in the atmosphere by analyzing SNR data (Signal-to-Noise Ratio) from GNSS (Global Navigation Satellite System) stations was investigated. The functionality of the method was confirmed by studying volcanic plumes from three areas: Iceland, Sicily and Indonesia. A number of programs were written for data analysis. The timing and direction of the observed detections for Eyjafjallaj¨okull (2010) and Etna (2006) proved to fit with data from other detection techniques. During early 2014 several volcanoes (i.a. Sinabung, Kelut and Merapi) in Indonesia were erupting relatively simultaneously. A large number of volcanic plumes could therefore be detected there. By combining data from several satellites and receivers information about the location of the volcanic ash plumes could be obtained. The advantages of this technique include its relatively low costs and its potential for continuous and comprehensive observation opportunities. In the future there are good opportunities for SNR data analysis from GNSS stations to function as a complement to current detection techniques.
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    Utveckling av modeller för studier av luftföroreningar
    (2015) Almqvist, Frida; Ekström, Katrin; Bohlin, Oskar; Mårtensson, Anton; Seljelid, Eirik; Chalmers tekniska högskola / Institutionen för rymd- och geovetenskap; Chalmers University of Technology / Department of Earth and Space Sciences
    Abstract The growing population combined with an overall higher standard of living results in higher emissions of nitrogen oxides, photochemical oxidants and volatile organic compounds. Air pollution models are important tools in surveying the effects of this development and understanding how emissions spread from their point of origin. The purpose of this project is to create a complete air pollution model, given a stationary one dimensional air parcel model, the ESX model. The model will follow the flight path of an air parcel, a trajectory, along which it will collect data concerning meteorology and toxic release. The atmosphere can be divided into different boundary layers where the mixing layer is the most interesting for air pollution studies. The mixing layer is characterized by high turbulence which gives a significant mixing of emissions. An airpollution model therefore has to consider equations concerning this layer and its height, the mixing height. The project has resulted in a greater understanding of atmospheric chemistry and meteorology, but also two separate air pollution models based on the ESX model, HY- ESX and EStraX. The models are developed and executable in a Linux environment. The main difference between the two models is in how they compute the trajectories, one uses third-party application HYSPLIT and the other calculates them directly from meteorological data supplied by ECMWF. Evaluation of the models precision hasnt been fully concluded due to problems with the ESX model, but both serve as systems that provide the ESX model with necessary data through trajectory generation.