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Showing 1 to 20 of 44 for “"DOAS"”.
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Physics Guided Machine Learning algorithm for MAX-DOAS retrieval
… Optical Absorption Spectroscopy (MAX-DOAS) is a passive remote sensing technique that has been widely used to derive aerosol extinction coefficient profiles and trace gas concentrations. The ill-posed nature of the MAX-DOAS inversion problem makes it almost impossible to design an …
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Aufbau und Einsatz eines Multibeam Instrumentes zur DOAS-tomographischen Messung zweidimensionaler Konzentrationsverteilungen
… Arbeit wurden erste tomographische Langpfad DOAS Messungen (TOMDOAS)an der Autobahn A656 vorgenommen. Mit zwei Langpfad DOAS Instrumenten wurde abwechselnd entlang von 16 Lichtwegen gemessen. Aus den Messungen konnten zweidimensionale Konzentrationsverteilungen von NO2, SO2 und O3 senkrecht …
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Tomographic Reconstruction of 2-D Atmospheric Trace Gas Distributions from Active DOAS Measurements
Applying the tomographic principle to active DOAS remote sensing leads to a novel technique for the measurement of atmospheric trace gas distributions. Standard analytical methods for the reconstruction of a scalar field from its line integrals cannot be used due to low numbers of light paths …
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Investigation of Inorganic Stratospheric Bromine using Balloon-Borne DOAS Measurements and Model Simulations
… In this study, stratospheric balloon-borne DOAS (Differential Optical Absorption Spectroscopy) measurements of bromine-monoxide (BrO) were analysed and interpreted using the 3-D CTM (Chemical Transport Model) SLIMCAT [Chipperfield98] and a 1-D photochemical model. Photochemical changes were …
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Airborne Multi AXis DOAS instrument and measurements of two-dimensional tropospheric trace gas distributions
The Airborne Multi AXis DOAS instrument was developed and successfully operated during four measurement campaigns. Depending on the purpose the instrument was installed on two different aeroplanes flying either close to the tropopause or in the mixing layer. In a detailed sensitivity study the …
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A DOAS Study on the Oxidation Mechanism of Aromatic Hydrocarbons under Simulated Atmospheric Conditions
… Optische Absorptions Spektroskopie (DOAS) wurde in einer systematischen Smog-Kammer Studie am Europäischen Photoreaktor (EUPHORE), CEAM-Institute, Valencia/Spanien angewandt. Das vorhandene DOAS-System wurde hierzu weiterentwickelt. Die Verzweigungsverhältnisse (Yields) der …
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Studies of the Stratospheric Nitrogen and Iodine Chemistry by Balloon-Borne DOAS Measurements and Model Calculations
… Differential Optical Absorption Spectroscopy (DOAS) measurements of stratospheric trace gas profiles. The focus of this study was to measure the vertical distribution of O3, NO2, IO, and OIO during different geophysical conditions. In combination with the results of a Fourier Transform …
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Evaluation and Application of Max-DOAS Methods for Monitoring Aerosols, NO2, and SO2 in Urban and Industrial Environments
… Optical Absorption Spectroscopy (MAX-DOAS) techniques allow a diversity of applications for studying atmospheric species, including the determination of emissions, vertical profiles, and the tropospheric column loading of trace gases. Deployment of the MAX-DOAS instrument during the …
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Analysis of Trace Gas Heterogeneity using In-Situ and Remote Sensing Measurement Techniques
Differential Optical Absorption Spectroscopy (DOAS) is a remote sensing spectroscopic technique capable of retrieving vertical column densities of trace gases in the atmosphere. While the technique can be used to retrieve vertical profiles of trace gases this retrieval is not applicable to …
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Field Measurements of Water Continuum and Water Dimer Absorption by Active Long Path Differential Optical Absorption Spectroscopy (DOAS)
… were carried out by means of active Long Path DOAS. The spectral regions of the 4n, 4n+d, and 5n water polyads were selected for the measurements. In these regions three water dimer absorption bands are predicted to exist almost free of interference by strong water monomer absorption. Within …
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Halogen Oxide Studies in the Boundary Layer by Multi Axis Differential Optical Absorption Spectroscopy and Active Longpath-DOAS
… layer were performed by ground-based MAX-DOAS, which was developed within this work. The measurements at the Hudson Bay represent the southernmost and first direct observations of Arctic surface ozone losses due to BrO and allowed for the first time to study the day and nighttime chemistry …
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Studies of Aldehydes in an Atmosphere Simulation Chamber
Im Zuge dieser Arbeit wurde ein DOAS-Instrument an der Atmosphären-Simulationskammer SAPHIR (Forschungszentrum Jülich) aufgebaut, das auf einem Vielfach-Reflektionssystem des White-Designs basiert. Das DOAS-Instrument ermöglichte erstmalig den Nachweis von NO3 an der Kammer. Ein NO3- Verlustprozess …
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Determining Emission Factors from Marine Vessels Employing Differential Optical Absorption Spectroscopy (DOAS) and Tunable Diode Laser Absorption Spectroscopy (TDLAS)
… remote measurements of SO2 and CO2 using active-DOAS and TDLAS. A demonstration of the feasibility of the project was carried out by measuring sulfur dioxide (SO2) and carbon dioxide (CO2) in real ship plumes along with ship schedule information at a field site near the Welland Canal, Ontario.
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A General Observational Strategy for Validation of Satellite NO₂ Retrievals using Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS)
… Optical Absorption Spectroscopy (MAX-DOAS) measurements at regular azimuth angle intervals on an hourly basis to validate satellite based DOAS measurements. Off-Axis MAX-DOAS Measurements taken in Blacksburg, Virginia, between November 2021 and April 2022 with an evenly distributed set …
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Development and Application of a Versatile Balloon-Borne DOAS Spectrometer for Skylight Radiance and Atmospheric Trace Gas Profile Measurements
… framework of this thesis, a novel balloon-borne DOAS instrument was developed, characterized in the laboratory and employed during 5 stratospheric balloon flights. Its light weight and small size allows versatile applications on different platforms and under several observation geometries …
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Remote Sensing of the Lower Atmosphere: From Surface Concentration to Mixing Layer Height
Differential Optical Absorption Spectroscopy (DOAS) is a remote sensing technique to detect different trace gas concentrations in the atmosphere. The Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements by the Pandora instrument scan the sky at different elevation angles …
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Retrieval of trace gases vertical profile in the lower atmosphere combining. Differential Optical Absorption Spectroscopy with radiative transfer models
… Optical Absorption Spectroscopy (MAX-DOAS), is a recent technique that represents a significant advance on the well-established DOAS, especially for what it concerns the study of tropospheric trace consituents. NO2 is an important trace gas in the lower troposphere due to the fact that …
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The Measurement of Atmospheric Species with Absorptions Close to the Actinic Flux Cut-Off by Active & MAX-DOAS: Chlorine Monoxide (CIO) & Sulphur Dioxide (SO2)
… of differential optical absorption spectroscopy (DOAS). In particular, we seek to determine whether this trace gas is present in any appreciable amount in ambient air during the wintertime owing to the widespread application of road salt. The study was performed at The Centre for Atmospheric …
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Derivation of Trace Gas Information combining Differential Optical Absorption Spectroscopy with Radiative Transfer Modelling
The Differential Optical Absorption Spectroscopy (DOAS) is an established remote sensing technique for atmospheric constituent probing. To derive quantitative distribution data of trace gas distributions it is necessary to combine novel measurement techniques like Multi-Axis DOAS with realistic …
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Vertical Profiles of NO 2 and HONO in the Planetary Boundary Layer
… Differential Optical Absorption Spectroscopy (LP-DOAS) instrument has been advanced to fully operational status and its optical and mechanical parameters were characterised. This system was used for long-term measurements (13 months) of vertical profiles of NO2 and HONO on three light paths above …
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