0000000000868715

AUTHOR

Thomas Wagner

showing 5 related works from this author

A new method for the identification of archaeological soils by their spectral signatures in the vis-NIR region

2020

Abstract This paper introduces a statistical method to identify spectral signatures of buried archaeological remains and distinguish them from spectra of the background soil in the visible to near infrared region. The proposed method is based on the Principal Component Analysis (PCA). The difference between an archaeological spectrum and non-archaeological soil spectra is quantified by a so-called R value. R values larger than 1 indicate that the spectrum represents an archaeological material. The method is successfully applied to samples from five study sites in Italy and Hungary with special conditions. The reflection spectra are taken in a time-efficient way with a field spectrometer. Th…

010506 paleontologyArcheologySpectral signature060102 archaeologySpectrometerNear-infrared spectroscopy06 humanities and the artsCC01 natural sciencesArchaeologyField (geography)Spectral linePrincipal component analysisReflection (physics)0601 history and archaeologySpectral resolutionGeology0105 earth and related environmental sciencesJournal of Archaeological Science: Reports
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Evaluation of the coupled high-resolution atmospheric chemistry model system MECO(n) using in situ and MAX-DOAS NO2 measurements

2021

We present high spatial resolution (up to 2.2×2.2 km2) simulations focussed over south-west Germany using the online coupled regional atmospheric chemistry model system MECO(n) (MESSy-fied ECHAM and COSMO models nested n times). Numerical simulation of nitrogen dioxide (NO2) surface volume mixing ratios (VMRs) are compared to in situ measurements from a network with 193 locations including background, traffic-adjacent and industrial stations to investigate the model's performance in simulating the spatial and temporal variability of short-lived chemical species. We show that the use of a high-resolution and up-to-date emission inventory is crucial for reproducing the spatial variability and…

Earthwork. FoundationsEmissionen Luftqualität NO2TA715-787ddc:550Environmental engineeringTA170-171
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Variation of the BrO/SO2 molar ratio in the plume of Tungurahua volcano between 2007 and 2017 and its relationship to volcanic activity

2019

International audience; Recent long-term observations of the bromine monoxide (BrO) to sulphur dioxide (SO2) molar ratio in volcanic plumes have suggested a link between changes in the BrO/SO2 ratio and the volcanic activity. Nevertheless, understanding of the mechanisms determining this link is still limited due to the lack of studies on volcanic bromine release from the melt into the atmosphere. We present the results of 10 years (2007–2017) of observations of the BrO/SO2 molar ratio in the volcanic plume of Tungurahua volcano, Ecuador. Following the nearly continuous eruptive activity from 1999 to 2008, Tungurahua showed alternating phases of eruptive activity separated by periods of qui…

Molarratio010504 meteorology & atmospheric sciencesBromine monoxideMineralogySO2010502 geochemistry & geophysics01 natural sciencesBrOMolar ratio[SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanologylcsh:Science0105 earth and related environmental sciencesObservational databasegeographygeography.geographical_feature_categorydegassingTungurahuaStrombolian eruptionPlumeNOVACvolcanoVolcanic plumeVolcano13. Climate actionDOASGeneral Earth and Planetary SciencesEnvironmental sciencelcsh:Q
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Evaluation of the coupled high-resolution atmospheric chemistry model system MECO(n) using in situ and MAX-DOAS NO<sub>2</sub&am…

2021

Abstract. We present high spatial resolution (up to 2.2×2.2 km2) simulations focussed over south-west Germany using the online coupled regional atmospheric chemistry model system MECO(n) (MESSy-fied ECHAM and COSMO models nested n times). Numerical simulation of nitrogen dioxide (NO2) surface volume mixing ratios (VMRs) are compared to in situ measurements from a network with 193 locations including background, traffic-adjacent and industrial stations to investigate the model's performance in simulating the spatial and temporal variability of short-lived chemical species. We show that the use of a high-resolution and up-to-date emission inventory is crucial for reproducing the spatial varia…

ECHAMAtmospheric Science010504 meteorology & atmospheric sciencesDifferential optical absorption spectroscopyElevation010501 environmental sciencesAtmospheric sciences01 natural sciencesAzimuthTroposphereBoundary layerAtmospheric chemistryEnvironmental scienceSpatial variability0105 earth and related environmental sciencesAtmospheric Measurement Techniques
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Negative Ce anomalies in Mn oxides: The role of Ce4+ mobility during water–mineral interaction

2012

We present one of the very rare natural examples of extremely negative Ce anomalies (up to 4 orders of magnitude) in manganese oxides, caused by higher mobility of Ce4+ compared to REE3+ in an aquatic environment. The young secondary Mn oxides formed together with fluorites and goethites during water–mineral interaction in a hydrothermal fluorite vein. Our findings are in contrast to the oxidative scavenging of Ce, which is commonly observed in Mn oxides. Comparison of REE patterns from modern mine waters with primary and secondary minerals demonstrates that this cannot be solely explained as a source-related feature or by immobilization of Ce, but must at least partially be the result of p…

MineralchemistryGeochemistry and PetrologyDissolved organic carbonInorganic chemistrychemistry.chemical_elementMineralogyActinideManganeseVein (geology)ScavengingFluoriteHydrothermal circulationGeochimica et Cosmochimica Acta
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