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The mixing ratios of methane (CH4) were recorded with high temporal and spatial resolution in Münster, Germany, to identify urban CH4 sources and to quantify the overall inner city CH4 emissions. Both mobile and stationary measurement techniques were employed. The background mixing ratios showed a diurnal cycle with higher values at night under stable stratification conditions. In the industrial park, periodic peaks were detected. Ten mappings of the urban CH4 mixing ratio were made with an instrumented cargo bicycle. Repeated local increases in mixing ratios were found at 13 individual locations. The emission rate was estimated to be 22.0 g h−1 km−1. A total of five leaks from the underground gas distribution network were identified. From the increase in background mixing ratio, the overall source strength of the study area was estimated to be 24.6 g m−2 a−1, which is approximately three times the total CH4 emissions from the city’s most recent emissions report. The contribution of point sources was 0.64 g m−2 a−1, suggesting that significant additional CH4 sources exist within the study area. In the interest of climate protection, there is an urgent need for further research on the urban CH4 sources and emission fluxes in detail.

RESUMEN: En el campo de la cosmología, el Fondo Cósmico de Microondas juega un papel funda mental. Dadas sus peculiares características, un profundo conocimiento del mismo permite entender aspectos clave de la historia del Universo, como pueden ser la formación de estructuras como galaxias y cúmulos o la estimación de parámetros cosmológicos, cruciales para comprender cómo ha evolucionado el Universo. La misión Planck ha obtenido, hasta la fecha, la mejor imagen del Fondo Cósmico de Microondas. Para ello, se han desarrolla do sofisticados métodos de separación de componentes difusas, cruciales en cosmología ya que, siendo una ciencia observacional, todos los datos están contaminados por foregrounds, fuentes que se encuentran en la línea de visión del observador, que son inevitables. Con este trabajo se quiere comprobar hasta qué punto un método simple como es ILC sirve aplicado a los complejos datos de Planck, resultando en un mapa con un error del 10 %, que no está mal, pero para poder hacer cosmología no es suficiente. ABSTRACT: In cosmology, the Cosmic Microwave Background plays a major role. Give its unique characteristics, it is key to comprehend crucial aspects abaout the history of the Universe, such as the formation of galaxies and cluster or estimating the cosmological parameters, needed to understand the evolution of the Universe. Planck mission has obtained, up to now, the best image of the Cosmic Microwave Background. To do so, complex diffuse source separation programs have been develop. They are a key piece of cosmology because it is an observational science. This means that every data collected is contaminated with not desired sources (foregrounds) that are present in the line of sight. This project intends to check the limits of a simple method, as ILC is, when applied to complex sets of data, like the Planck ones. The resultant map has a 10% error, which is not bad, but not enough to perform cosmology. Grado en Física