Institution
University of Bremen
Education•Bremen, Germany•
About: University of Bremen is a education organization based out in Bremen, Germany. It is known for research contribution in the topics: Population & Glacial period. The organization has 14563 authors who have published 37279 publications receiving 970381 citations. The organization is also known as: Universität Bremen.
Topics: Population, Glacial period, SCIAMACHY, Sea ice, Holocene
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TL;DR: In this article, the tropical South American LGM data were interpreted from pollen, geochemical, and δ18O (stable oxygen isotope) data from Brazil and selected surrounding areas and the available terrestrial data were consistent with the SST derived precipitation data for the tropical forests in Brazil and for Africa.
227 citations
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TL;DR: In this article, the authors investigated the primary biodegradation of different N-imidazoles, imidazolium, pyridinium, and 4-(dimethylamino)pyrinium compounds substituted with various alkyl side chains and their analogues containing functional groups.
227 citations
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TL;DR: In this paper, a new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described, which uses the sunlight scattered in the zenith sky as the light source and the method of Differential Optical Absorption Spectroscopy (DOAS) to derive column amounts of absorbers like ozone and nitrogen dioxide.
Abstract: . A new approach to derive tropospheric concentrations of some atmospheric trace gases from ground-based UV/vis measurements is described. The instrument, referred to as the MAX-DOAS, is based on the well-known UV/vis instruments, which use the sunlight scattered in the zenith sky as the light source and the method of Differential Optical Absorption Spectroscopy (DOAS) to derive column amounts of absorbers like ozone and nitrogen dioxide. Substantial enhancements have been applied to this standard setup to use different lines of sight near to the horizon as additional light sources (MAX - multi axis). Results from measurements at Ny-Alesund (79° N, 12° E) are presented and interpreted with the full-spherical radiative transfer model SCIATRAN. In particular, measurements of the oxygen dimer O4 which has a known column and vertical distribution in the atmosphere are used to evaluate the sensitivity of the retrieval to parameters such as multiple scattering, solar azimuth, surface albedo and refraction in the atmosphere and also to validate the radiative transfer model. As a first application, measurements of NO2 emissions from a ship lying in Ny-Alesund harbour are presented. The results of this study demonstrate the feasibility of long term UV/vis multi axis measurement that can be used to derive not only column amounts of different trace gases but also some information on the vertical location of these absorbers.
226 citations
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TL;DR: In this article, column-averaged volume mixing ratios of carbon dioxide and methane retrieved from the GOSAT SWIR XCO2 and XCH4 (Version 01.xx) were compared with the reference calibrated data obtained by ground-based high-resolution Fourier Transform Spectrometers (g-b FTSs) participating in the Total Carbon Column Observing Network (TCCON).
Abstract: . Column-averaged volume mixing ratios of carbon dioxide and methane retrieved from the Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed observation (GOSAT SWIR XCO2 and XCH4) were compared with the reference calibrated data obtained by ground-based high-resolution Fourier Transform Spectrometers (g-b FTSs) participating in the Total Carbon Column Observing Network (TCCON). Preliminary results are as follows: the GOSAT SWIR XCO2 and XCH4 (Version 01.xx) are biased low by 8.85 ± 4.75 ppm (2.3 ± 1.2 %) and 20.4 ± 18.9 ppb (1.2 ± 1.1 %), respectively. The standard deviation of the GOSAT SWIR XCO2 and XCH4 is about 1 % (1 σ) after correcting the negative biases of XCO2 and XCH4 by 8.85 ppm and 20.4 ppb, respectively. The latitudinal distributions of zonal means of the GOSAT SWIR XCO2 and XCH4 show similar features to those of the g-b FTS data except for the negative biases in the GOSAT data.
226 citations
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TL;DR: Concentrations and isotopic compositions of ethane and propane in cold, deeply buried sediments from the southeastern Pacific are best explained by microbial production of these gases in situ, upsetting the general belief that hydrocarbons larger than methane derive only from thermal degradation of fossil organic material.
Abstract: Concentrations and isotopic compositions of ethane and propane in cold, deeply buried sediments from the southeastern Pacific are best explained by microbial production of these gases in situ. Reduction of acetate to ethane provides one feasible mechanism. Propane is enriched in (13)C relative to ethane. The amount is consistent with derivation of the third C from inorganic carbon dissolved in sedimentary pore waters. At typical sedimentary conditions, the reactions yield free energy sufficient for growth. Relationships with competing processes are governed mainly by the abundance of H(2). Production of C(2) and C(3) hydrocarbons in this way provides a sink for acetate and hydrogen but upsets the general belief that hydrocarbons larger than methane derive only from thermal degradation of fossil organic material.
225 citations
Authors
Showing all 14961 results
Name | H-index | Papers | Citations |
---|---|---|---|
Roger Y. Tsien | 163 | 441 | 138267 |
Klaus-Robert Müller | 129 | 764 | 79391 |
Ron Kikinis | 126 | 684 | 63398 |
Ulrich S. Schubert | 122 | 2229 | 85604 |
Andreas Richter | 110 | 769 | 48262 |
Michael Böhm | 108 | 755 | 66103 |
Juan Bisquert | 107 | 450 | 46267 |
John P. Sumpter | 101 | 266 | 46184 |
Jos Lelieveld | 100 | 570 | 37657 |
Michael Schulz | 100 | 759 | 50719 |
Peter Singer | 94 | 702 | 37128 |
Charles R. Tyler | 92 | 325 | 31724 |
John P. Burrows | 90 | 815 | 36169 |
Hans-Peter Kriegel | 89 | 444 | 73932 |
Harald Haas | 85 | 750 | 34927 |