A5091435667- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Vehicle emissions and performance
- Tropical and Extratropical Cyclones Research
- Ocean Waves and Remote Sensing
- Methane Hydrates and Related Phenomena
- Maritime Transport Emissions and Efficiency
- Radiomics and Machine Learning in Medical Imaging
- Meteorological Phenomena and Simulations
- Atmospheric aerosols and clouds
- Scientific Computing and Data Management
- Hydrocarbon exploration and reservoir analysis
- Water Quality Monitoring and Analysis
- Greenhouse Technology and Climate Control
- Innovative Approaches in Technology and Social Development
- Geological and Geophysical Studies
- Solar and Space Plasma Dynamics
- Peatlands and Wetlands Ecology
- Distributed and Parallel Computing Systems
- Gas Sensing Nanomaterials and Sensors
- Fire effects on ecosystems
ETH Zurich
2005-2023
University of Reading
2020
École Polytechnique Fédérale de Lausanne
2008-2009
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
1998-2006
Board of the Swiss Federal Institutes of Technology
2006
German Climate Computing Centre
2001
University of Cologne
1998
Abstract. In recent years a number of chemistry-climate models have been developed with an emphasis on the stratosphere. Such cover wide range time scales integration and vary considerably in complexity. The results specific diagnostics are here analysed to examine differences amongst individual observations, assess consistency model predictions, particular focus polar ozone. For example, many indicate significant cold bias high latitudes, "cold pole problem", particularly southern...
Abstract Estimates of annual‐mean stratospheric temperature trends over the past twenty years, from a wide variety models, are compared both with each other and observed cooling seen in trend analyses using radiosonde satellite observations. The modelled driven by changes ozone (either imposed observations or calculated model), carbon dioxide relatively well‐mixed greenhouse gases, water vapour. comparison shows that whilst models generally simulate similar patterns vertical profile...
Abstract. To estimate the impact of emissions by road, aircraft and ship traffic on ozone OH in present-day atmosphere six different atmospheric chemistry models have been used. Based newly developed global emission inventories for data sets each model performed sensitivity simulations reducing transport sector 5%. The results indicate that annual average lower tropospheric responds most sensitive to (50.6%±10.9% total induced perturbation), followed road (36.7%±9.3%) exhausts (12.7%±2.9%),...
To make sound decisions in the face of climate change, government agencies, policymakers and private stakeholders require suitable information on local to regional scales. In Switzerland, development change scenarios is strongly linked adaptation strategy Confederation. The current for Switzerland CH2018 - released form six user-oriented products were result an intensive collaboration between academia administration under umbrella National Centre Climate Services (NCCS), accounting user...
Abstract. We describe version 2.0 of the chemistry-climate model (CCM) SOCOL. The new includes fundamental changes transport scheme such as transporting all chemical species individually and applying a family-based correction for mass conservation nitrogen, chlorine bromine groups, revised ozone, furthermore more detailed halogen reaction deposition schemes, cirrus parameterisation in tropical tropopause region. By means these manages to overcome or considerably reduce deficiencies recently...
Abstract. A transient simulation with the interactively coupled chemistry-climate model (CCM) E39/C has been carried out which covers 40-year period between 1960 and 1999. Forcing of natural anthropogenic origin is prescribed where characteristics are sufficiently well known typical timescales slow compared to synoptic timescale so that simulated atmospheric chemistry climate evolve under a "slowly" varying external forcing. Based on observations, sea surface temperature (SST) ice cover...
Abstract. The coupled climate-chemistry model ECHAM4.L39(DLR)/CHEM is presented which enables a simultaneous treatment of meteorology and atmospheric chemistry their feedbacks. This the first interactively combines general circulation with chemical model, employing most important reactions species necessary to describe stratospheric upper tropospheric ozone chemistry, computationally fast enough allow long-term integrations currently available computer resources. possible as time-step used...
Abstract Although large total ozone decreases occurred in the Northern Hemisphere extratropics years after volcanic eruption of Mt. Pinatubo that are generally attributed to eruption, comparable did not emerge Southern Hemisphere. To study this missing decrease, a multiple linear regression was applied Chemical and Dynamical Influences on Decadal Ozone Change (CANDIDOZ) Assimilated Three-Dimensional (CATO) dataset including solar cycle, quasi-biennial oscillation (QBO), effect eruptions,...
Abstract. We report results from a multiple linear regression analysis of long-term total ozone observations (1979 to 2000, by TOMS/SBUV), temperature reanalyses (1958 NCEP), and two chemistry-climate model simulations (1960 1999, ECHAM4.L39(DLR)/CHEM (=E39/C), MAECHAM4-CHEM). The runs are transient experiments, where observed sea surface temperatures, increasing source gas concentrations (CO2, CFCs, CH4, N2O, NOx), 11-year solar cycle, volcanic aerosols the quasi-biennial oscillation (QBO)...
Abstract To date, the radiative impact of dust and Saharan air layer (SAL) on North Atlantic hurricane activity is not yet known. According to previous studies, stabilizes atmosphere due absorption solar radiation but thus shifts convection regions more conducive for genesis. Here we analyze differences in genesis frequency from ensemble sensitivity simulations with radiatively active inactive aerosol‐climate model ECHAM6‐HAM. We investigate burden other hurricane‐related variables determine...
ECHAM3/CHEM is used to estimate the future development of ozone layer. The general circulation model ECHAM3 and chemistry module CHEM are coupled in a CTM‐like mode, i.e. no feedback simulated chemical species on radiation considered. Currently does not include bromine chemistry. Two time‐slice experiments representing 1991 2015 conditions carried out. Chemical transported by winds calculated with different CO 2 mixing ratios as proxy for other greenhouse‐gases. For 2015, adopted increase...
Abstract. We present ozone measurements of the Global Atmospheric Sampling Program (GASP) performed from four commercial and one research aircraft in late 1970s to compare them with respective ongoing MOZAIC project. Multi-annual averages UT/LS were built using data sets (1975–1979 1994–2001), long-term changes between 1990s derived by comparison. The binned relative dynamical tropopause separate UT LS air masses. analysed equivalent latitudes. In UT, pronounced increases 20–40% are found...
Abstract. Interannual-to-decadal variability in stratospheric ozone and climate have a number of common sources, such as variations solar irradiance, aerosol loading due to volcanic eruptions, El Niño Southern Oscillation the quasi-biennial oscillation (QBO). Currently available data records well model simulations addressing chemical mostly cover only past few decades, which is often insufficient address natural interannual-to-decadal variability. Here we make use recently reconstructed...
The relationship between North Atlantic Oscillation (NAO) changes and northern stratospheric ozone recovery in the near future is investigated using four timeslice scenarios (1960, 1980, 1990, 2015) of chemistry‐climate model ECHAM4.L39(DLR)/CHEM. A wintertime NAO index composite study scenario “1990” ECMWF reanalyses shows typical patterns: positive phase polar vortex stronger colder than negative phase. In troposphere, marked by increased variance across stormtrack whereas suggestive...
Abstract. To estimate the impact of emissions by road, aircraft and ship traffic on ozone OH present-day atmosphere seven different atmospheric chemistry models simulated composition year 2003. Based newly developed global emission inventories for maritime data sets each model performed a series five simulations: A base scenario using full set emissions, three sensitivity studies with individual sector transport reduced 5% one simulation all related 5%. The approach minimizes non-linearities...
Abstract. We present ozone measurements of the Global Atmospheric Sampling Program (GASP) performed from four commercial and one research aircraft in late 1970s. The GASP quality assurance control program was reviewed, an climatology upper troposphere lower stratosphere (UT/LS) years 1975–1979 built. data set estimated to have overall uncertainty 9% or 3 ppb whichever is greater for first two 4% remaining years, i.e. after implementation silicone rubber membranes pumps. Two cases nearly...
Abstract. Actinic fluxes at large solar zenith angles (SZAs) are important for atmospheric chemistry, especially under twilight conditions in polar winter and spring. The results of a sensitivity experiment employing the fully coupled 3D chemistry-climate model ECHAM4.L39(DLR)/CHEM have been analysed to quantify impact SZAs larger than 87.5º on dynamical chemical processes lower stratosphere, particular their influence ozone layer. Although actinic small, concentrations significantly...
Abstract We investigate the circumstances under which Saharan air layer (SAL) has a negative impact on intensification of tropical cyclones (TCs) over North Atlantic Ocean. Using hurricane tracking, aerosol optical depth (AOD) data, and meteorological analyses, we analyze interaction SAL with 52 named TCs that formed east central south Cape Verde islands between 2004 2017. Following categorization influences TC by Dunion Velden, only 21% investigated storms can be classified (28% all...
Abstract. We describe version 2.0 of the chemistry-climate model (CCM) SOCOL. The new includes fundamental changes transport scheme such as transporting all chemical species individually and applying a family-based correction for mass conservation nitrogen, chlorine bromine groups, revised ozone, furthermore more detailed halogen reaction deposition schemes, cirrus parameterisation in tropical tropopause region. By means these manages to overcome or considerably reduce deficiencies recently...
Abstract. We report results from a multiple linear regression analysis of long-term total ozone observations (1979 to 2002, by TOMS/SBUV), temperature reanalyses (1958 NCEP), and two chemistry-climate model simulations (1960 1999, ECHAM4.L39(DLR)/CHEM (=E39/C), MAECHAM4-CHEM). The runs are transient experiments, where observed sea surface temperatures, increasing source gas concentrations (CO2, CFCs, CH4, N2O, NOx), 11-year solar cycle, volcanic aerosols the quasi-biennial oscillation (QBO)...
Although large total ozone decreases occurred in the Northern Hemisphere extratropics years after volcanic eruption of Mt. Pinatubo that are generally attributed to eruption, comparable did not emerge Southern Hemisphere. To study this missing decrease, a multiple linear regression was applied Chemical and Dynamical Influences on Decadal Ozone Change (CANDIDOZ) Assimilated Three-Dimensional (CATO) dataset including solar cycle, quasi-biennial oscillation (QBO), effect eruptions, lower...
Abstract. The knowledge of historical ozone in the upper troposphere/lower stratosphere (UT/LS) region is mostly confined to regular measurements from a number ozonesonde stations. We present Global Atmospheric Sampling Program (GASP) performed four commercial and one research aircraft during 1975 1979. Using GASP data, UT/LS climatology 1975–1979 was built. Seasonality concentrations UT middle, subtropical tropical regions northern hemisphere (NH) are generally agreement with other...