A5082105225- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Air Quality Monitoring and Forecasting
- Spectroscopy and Laser Applications
- Atmospheric aerosols and clouds
- Mercury impact and mitigation studies
- Methane Hydrates and Related Phenomena
- Arctic and Antarctic ice dynamics
- Water Quality Monitoring and Analysis
- Marine and coastal ecosystems
- Air Quality and Health Impacts
- Geochemistry and Geologic Mapping
- Cryospheric studies and observations
- Ionosphere and magnetosphere dynamics
- Ocean Acidification Effects and Responses
- Isotope Analysis in Ecology
- Polar Research and Ecology
- Vehicle emissions and performance
- Advanced Chemical Sensor Technologies
- Calibration and Measurement Techniques
- Astro and Planetary Science
- Spacecraft and Cryogenic Technologies
- Analytical Chemistry and Sensors
- Oil Spill Detection and Mitigation
Heidelberg University
2016-2025
Institut für Energie- und Umweltforschung Heidelberg
2007-2023
University of Leicester
2004-2007
National Centre for Earth Observation
2006
Fritz Haber Institute of the Max Planck Society
1985
Bielefeld University
1985
Abstract. During springtime in the polar regions, unique photochemistry converts inert halide salt ions (e.g. Br−) into reactive halogen species Br atoms and BrO) that deplete ozone boundary layer to near zero levels. Since their discovery late 1980s, research on depletion events (ODEs) has made great advances; however many key processes remain poorly understood. In this article we review history, chemistry, dependence environmental conditions, impacts of ODEs. This shown central role...
Multi AXis Differential Optical Absorption Spectroscopy (MAX‐DOAS) observations of the oxygen dimer O 4 which can serve as a new method for determination atmospheric aerosol properties are presented. Like established methods, e.g., Sun radiometer and LIDAR measurements, MAX‐DOAS determine optical under conditions (not dried). However, novel technique has two major advantages: It utilizes differential absorption structures thus does not require absolute radiometric calibration. In addition,...
A new retrieval algorithm for the determination of aerosol properties using Multi‐AXis Differential Optical Absorption Spectroscopy (MAX‐DOAS) measurements based on nonlinear optimal estimation is presented. Using simulated MAX‐DOAS optical depth collision complex oxygen (O 4 ) as well variation intensity diffuse skylight measured at different viewing directions and wavelengths, capability this measurement technique to derive extinction profile information phase function single scattering...
The European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System) operates global-scale monitoring system atmospheric trace gases, aerosols and clouds utilising the existing global civil aircraft. This new infrastructure builds on heritage of former research projects MOZAIC (Measurement Ozone Water Vapour Airbus In-service Aircraft) CARIBIC (Civil Regular Investigation Atmosphere Based an Instrument Container). continues within acts as important airborne...
Abstract. The results of a comparison exercise radiative transfer models (RTM) various international research groups for Multiple AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) viewing geometry are presented. Besides the assessment agreement between different models, second focus was systematic investigation sensitivity MAX-DOAS technique under geometries and aerosol conditions. In contrast to previous exercises, box-air-mass-factors (box-AMFs) atmospheric height layers were...
Abstract. We present aerosol and trace gas profiles derived from MAX-DOAS observations. Our inversion scheme is based on simple profile parameterisations used as input for an atmospheric radiative transfer model (forward model). From a least squares fit of the forward to measurements, two parameters are retrieved including integrated quantities (aerosol optical depth or vertical column density), describing height shape respective profiles. these results, extinction mixing ratios can also be...
[1] We present results from multiaxis differential optical absorption spectroscopy (MAX-DOAS) and long-path DOAS (LP-DOAS) measurements performed at the North Slope of Alaska February to April 2009 as part Ocean-Atmosphere-Sea Ice-Snowpack Barrow campaign. For first time, vertical profiles aerosol extinction BrO in boundary layer were retrieved simultaneously MAX-DOAS using method optimal estimation. Even very low visibility, thickness are good agreement with colocated ceilometer Sun...
Abstract. In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RH<30–40%). Since ambient particles experience hygroscopic growth at enhanced RH, their microphysical and optical properties – especially light scattering also strongly dependent on RH. The knowledge of this RH effect is crucial importance for climate forcing calculations or comparison remote sensing with measurements. Here, we will present results from a four-month campaign...
Abstract. In June 2009, 22 spectrometers from 14 institutes measured tropospheric and stratospheric NO2 the ground for more than 11 days during Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI), at Cabauw, NL (51.97° N, 4.93° E). All visible instruments used a common wavelength range set cross sections spectral analysis. Most were multi-axis design with analysis by differential spectroscopy software (MAX-DOAS), whose non-zenith slant columns compared examining...
[1] A measurement intensive was carried out in Barrow, Alaska, spring 2009 as part of the Ocean-Atmosphere-Sea-Ice–Snowpack (OASIS) program. The central focus this campaign role halogen chemistry Arctic. chemical ionization mass spectrometer (CIMS) performed situ bromine oxide (BrO) measurements. In addition, a long path-differential optical absorption (LP-DOAS) measured average concentration BrO along light paths either 7.2 or 2.1 km. comparison 1 min observations from both instruments is...
Abstract. In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants for period 17 d during the Second Cabauw Intercomparison campaign Nitrogen Dioxide measuring Instruments (CINDI-2) that took place at Cabauw, Netherlands (51.97∘ N, 4.93∘ E). We report on outcome formal semi-blind intercomparison exercise, which was held under umbrella Network Detection Atmospheric Composition Change (NDACC) and European Space Agency (ESA). The three major goals...
In the polar tropospheric boundary layer, reactive halogen species (RHS) are responsible for ozone depletion as well oxidation of elemental mercury and dimethyl sulphide. After sunrise, air masses enriched in bromine cover areas several million square kilometers. Still, source release mechanisms halogens not completely understood. We report measurements oxides performed Amundsen Gulf, Arctic, during spring 2008. Active long-path differential optical absorption spectroscopy (LP-DOAS) were set...
Abstract. We present intercomparison results for formaldehyde (HCHO) slant column measurements performed during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI) that took place in Cabauw, Netherlands, summer 2009. During two months, nine atmospheric research groups simultaneously operated MAX-DOAS (MultiAXis Differential Optical Absorption Spectroscopy) instruments various designs to record UV-visible spectra scattered sunlight at different elevation...
Abstract. From June to July 2009 more than thirty different in-situ and remote sensing instruments from all over the world participated in Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI). The took place at KNMI's Experimental Site Atmospheric Research (CESAR) Netherlands. Its main objectives were determine accuracy of state-of-the-art ground-based measurement techniques detection atmospheric nitrogen dioxide (both sensing), investigate their usability...
Abstract. The second Cabauw Intercomparison of Nitrogen Dioxide measuring Instruments (CINDI-2) took place in (the Netherlands) September 2016 with the aim assessing consistency multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements tropospheric species (NO2, HCHO, O3, HONO, CHOCHO and O4). This was achieved through coordinated operation 36 spectrometers operated by 24 groups from all over world, together a wide range supporting reference observations (in situ...
Abstract. A first direct intercomparison of aerosol vertical profiles from Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations, performed during the Cabauw Intercomparison Campaign Nitrogen Dioxide measuring Instruments (CINDI) in summer 2009, is presented. Five out 14 participants CINDI campaign reported extinction and optical thickness (AOT) as deduced observations differential slant column densities oxygen collision complex (O4) at different elevation angles....
Abstract. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) is a widely used measurement technique for the detection of variety atmospheric trace gases. Using inverse modelling, observation gas column densities along different lines sight enables retrieval aerosol and vertical profiles in boundary layer using appropriate algorithms. In this study, ability eight profile algorithms to reconstruct assessed on basis synthetic measurements. Five are based optimal estimation...
Abstract. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) and direct sun NO2 vertical column network data are used to investigate the accuracy of tropospheric measurements GOME-2 instrument on MetOp-A satellite platform OMI Aura. The study is based 23 MAX-DOAS 16 instruments at stations distributed worldwide. A method quantify correct for horizontal dilution effects in heterogeneous field conditions proposed. After systematic application this correction urban sites, found...
Abstract. Volatile organic compounds (VOCs) are key precursors of particulate matter and tropospheric ozone. Although the terrestrial biosphere is by far largest source VOCs into atmosphere, emissions biogenic remain poorly constrained at regional scale. In this work, we derive top-down over Europe using weekly averaged TROPOMI formaldehyde (HCHO) data from 2018 to 2021. The systematic bias HCHO columns characterized corrected for based on comparisons with FTIR seven European stations....
We investigate chemistry and dynamics of bromine explosion events during Antarctic spring 1999 2000 using ground‐based differential optical absorption spectroscopy (DOAS) observations BrO, surface ozone, ozone sounding measurements performed at the German research station Neumayer, located coast continent (70°39′S, 8°15′W). BrO maps from GOME satellite instrument show huge areas elevated above sea ice around Antarctica, covering several thousand square kilometers. Although Neumayer is a...
We present and demonstrate a relatively simple algorithm, which converts set of slant column density measurements oxygen dimers (O4) NO2 at several different elevation angles to determine the atmospheric aerosol extinction absolute concentration mixing ratio within boundary layer. In addition height layer can usually be derived, also technique readily extended other trace gases including SO2, CH2O, or glyoxal. The algorithm is based on precise radiation transport modelling determination,...
Abstract. In October 2009, shipborne Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were performed during the TransBrom campaign over western Pacific Ocean (≈ 40° N to 20° S). Vertical tropospheric trace gas columns and profiles of nitrogen dioxide (NO2) formaldehyde (HCHO) as well stratospheric NO2 retrieved in order validate corresponding from GOME-2 SCIAMACHY satellite instruments estimate background concentrations these gases. All reproduced same...
Abstract. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations of aerosols and trace gases can be strongly influenced by clouds. Thus, it is important to identify clouds characterise their properties. In this study we investigate the effects on several quantities which derived from MAX-DOAS observations, like radiance, colour index (radiance ratio at two selected wavelengths), oxygen dimer O4 fraction inelastically scattered light (Ring effect). To clouds, these...