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Echo planar imaging is characterized by scanning the 2D k-space after a single excitation. Different sampling patterns have been proposed. A technically feasible method uses a sinusoidal readout gradient resulting is measured data that does not sample k-space in an equidistant manner. In order to employ a conventional 2D-FFT image reconstruction, the data(More)
Limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the ENVIronmental SATellite (ENVISAT) are used to derive the first global distribution of peroxyacetyl nitrate (PAN) in the upper troposphere. PAN is generated in polluted tropospheric air masses and acts as a carrier of NO in the cold upper troposphere.(More)
Within this ENVISAT validation project [AO-191] ground-based measurements of different techniques have been performed at Kiruna in the Arctic and on Tenerife Island in the subtropics. These ground-based data were used to validate column amounts derived from SCIAMACHY as well as profiles from MIPAS. While SCIAMACHY O 3 columns of versions up to 3.53 differ(More)
To evaluate the physiological thresholds of neuromuscular stimulation relevant to very fast NMR imaging studies that use gradient switching at frequencies of 1-2 kHz and a maximum magnetic field of up to 10 mT, a series of studies were done with human volunteers using an experimental echo planar gradient coil set. The threshold for induction of localized(More)
We present a new steady-state imaging sequence, which simultaneously allows in a single acquisition the formation of two MR images with clearly different contrasts. The contrast of the first image is FISP-like, whereas the second image is strongly T2-weighted. In principle the T2 values in the image can be calculated from the combination of the first and(More)
The Geostationary Fourier Imaging Spectrometer (GeoFIS) is proposed as part of the European Geostationary Tropospheric Pollution Explorer (GeoTroPE) mission. For this mission, two instruments are considered: one covering the thermal infrared region (GeoFIS) and one covering the ultraviolet–visible and near-infrared regions (GeoSCIA). The geostationary orbit(More)
We report on the dependance of ozone volume mixing ratio profiles, retrieved from spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), on different retrieval setups such as different a-priori profiles, regularization strengths and spectral regions used for analysis. MIPAS is a spaceborne limb-viewing Fourier 5 transform infrared(More)
One of the major challenges facing atmospheric sciences is to assess, understand and quantify the impact of natural and an-thropogenic pollution on the quality of life on Earth on a local, regional and continental scale. It has become apparent that pollution originating from local/regional events can have serious effects on the composition of the lower(More)
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the ENVISAT satellite provides profiles of temperature and various trace-gases from limb-viewing mid-infrared emission measurements. The stratospheric nitric acid (HNO 3) from September 2002 to March 2004 was retrieved from the MIPAS observations us-5 ing the science-oriented data(More)