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[1] After a decade of stable or slightly decreasing global methane concentrations, ground‐based in situ data show that CH4 began increasing again in 2007 and that this increase continued through 2009. So far, space‐based retrievals sensitive to the lower troposphere in the time period under consideration have not been available. Here we report a long‐term(More)
The specific conditions of catalyst pretreatment are known to determine the properties of iron-based Fischer-Tropsch catalysts to a large extent. The phenomenon has been investigated and it was found that the extent of reduction of the surface has a major influence on the catalytic activity and selectivity. Methane is formed as the main product on those(More)
The GDAQI project addresses GOME in-orbit level 1 calibration issues including air-vacuum changes (UV parabola) after launch, instrument performance degradation with time, instrument polarization sensitivity (and its changes with time), etalon spectral modulation and dichroic mirror out gassing (Fig.1). New data analysis diagnostics have been developed(More)
Degradation of optical components in space is a problem affecting many remote sensing instruments. In the Global Ozone Monitoring Experiment (GOME) on board ERS-2, the light backscattered by the Earth’s atmosphere follows a different optical path through the spectrometer than solar irradiance. GOME has been therefore designed to monitor degradation of(More)
A comparison is made between some conventional and new methods for detecting stars in crowded stellar images. The new methods are (1) Lucy-Richardson deconvolution of the image before detection, and (2) fitting the Point Spread Function to each pixel in the image. These methods are applied to both a synthetic image and a real one. The deconvolution method(More)
Branched products are mainly formed during secondary isomerization reactions, and not in the main synthesis reaction itself. The extent of branching is a function of the catalyst formulation. High acidity and a low hydrogenation strength of the catalyst (normally found in catalysts with a high basicity) favour branching. The latter can be explained by the(More)
It is possible to extract the number of stars per magnitude interval (luminosity function) from the histogram of a crowded stellar field image if the point spread function is known sufficiently well. There are no severe uniqueness problems with the solution. The method is sensitive to errors in the point spread function, but the shape of the luminosity(More)