Steffen Beirle

Simultaneous global observations of glyoxal and formaldehyde from space

[1] The first global simultaneous observations of glyoxal (CHOCHO) and formaldehyde (HCHO) columns retrieved from measurements by the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) satellite instrument are presented and compared to model calculations. The global pattern of the distribution of CHOCHO is similar to that of HCHO. High values are observed over areas with large biogenic isoprene emissions (Central Africa, parts of South America, and Indonesia). Also regions with biomass burning and anthropogenic pollution exhibit elevated levels of CHOCHO. The ratio of the columns of CHOCHO to HCHO is generally of the order of 0.05 in regions having biogenic emissions, which is in reasonable agreement with the current understanding of the oxidation of hydrocarbons emitted by the biosphere. However and in contrast to our model, high values of both HCHO and CHOCHO are also observed over areas of the tropical oceans. This is tentatively attributed to outflow from the continents and local oceanic biogenic sources of the precursors of HCHO and CHOCHO. Citation: Wittrock, F., A. Richter, H. Oetjen, J. P. Burrows, M. Kanakidou, S. Myriokefalitakis, R. Volkamer, S. Beirle, U. Platt, and T. Wagner (2006), Simultaneous global observations of glyoxal and formaldehyde from space, Geophys. Res. Lett., 33, L16804, doi:10.1029/2006GL026310.

Megacity emissions and lifetimes of nitrogen oxides probed from space

Analysis of downwind plume evolution using satellite observations can be used for air pollution estimates. Megacities are immense sources of air pollutants, with large impacts on air quality and climate. However, emission inventories in many of them still are highly uncertain, particularly in developing countries. Satellite observations allow top-down estimates of emissions to be made for nitrogen oxides (NOx = NO + NO2), but require poorly quantified a priori information on the NOx lifetime. We present a method for the simultaneous determination of megacity NOx emissions and lifetimes from satellite measurements by analyzing the downwind patterns of NO2 separately for different wind conditions. Daytime lifetimes are ~4 hours at low and mid-latitudes, but ~8 hours in wintertime for Moscow. The derived NOx emissions are generally in good agreement with existing emission inventories, but are higher by a factor of 3 for the Saudi Arabian capital Riyadh.

Evaluation of long‐term tropospheric NO2 data obtained by GOME over East Asia in 1996–2002

Long-term tropospheric nitrogen dioxide (NO2) column data obtained by the Global Ozone Monitoring Experiment (GOME) (G-NO2) are evaluated to confirm the trends found in tropospheric NO2 abundances over East Asia between 1996 and 2002. For three locations in Central and East Asia, the G-NO2 values are compared with tropospheric columns estimated from coincident observations of total NO2 by ground-based UV/visible spectrometers and stratospheric NO2 by satellite solar occultation sensors (E-NO2). The comparisons show a slight linear drift in G-NO2 data from 1996 to 2002. However, it is much smaller than the standard deviation of the differences between G-NO2 and E-NO2 and much smaller than the increasing trends in NO2 seen by GOME over the industrial areas of China, demonstrating the validity of the trends estimated using the GOME data.

GOME Observations of Stratospheric Trace Gas Distributions during the Splitting Vortex Event in the Antarctic Winter of 2002. Part I: Measurements

Abstract Measurements from the Global Ozone Monitoring Experiment (GOME) are used to study the chemical evolution of the stratosphere during the unusual 2002 winter in the Southern Hemisphere. The results show that chlorine activation as indicated by OClO columns was similar to previous years in the vortex until the major warming on 26 September 2002 after which it decreased rapidly. Similarly, NO2 columns were only slightly larger than in previous years before the warming, indicating strong denoxification and probably also denitrification. After the warming, very large NO2 columns were observed for a few days, which then decreased again as the vortex reestablished itself until the final warming. Ozone columns were much larger than in any previous year from September onward, mainly as a result of the unusual dynamical situation. Analysis of the global long-term time series of GOME measurements since 1996 provides a unique opportunity to set the austral winter 2002 into perspective. The GOME data reveal th...

Monitoring of atmospheric trace gases, clouds, aerosols and surface properties from UV/vis/NIR satellite instruments

A new generation of UV/vis/near-IR satellite instruments like GOME (since 1995), SCIAMACHY (since 2002), OMI (since 2004), and GOME-2 (since 2006) have allowed one to measure backscattered solar radiance from the Earth with moderate spectral resolution over a large wavelength range (240–790 nm). The SCIAMACHY instrument also includes additional spectral channels in the near-IR. From the measured spectra several important stratospheric and tropospheric trace gases (e.g. O_3, NO_2, OClO, HCHO, SO_2, BrO, H_2O) as well as clouds, aerosols and surface properties can be determined from space. Because of its extended spectral range, the SCIAMACHY instrument also allows the retrieval of greenhouse gases (CO_2, CH_4) and CO in the near-IR. Almost all of the tropospheric trace gases have been observed by these instruments for the first time. From satellite data it is possible to investigate their temporal and spatial variation. Also, different sources can be characterized and quantified. The derived global distributions can serve as input and for the validation of atmospheric models. Here we give an overview of the current status of these new instruments and data products and their recent applications in the investigation of various atmospheric and oceanic phenomena.

Direct observation of two dimensional trace gas distributions with an airborne Imaging DOAS instrument

In many investigations of tropospheric chemistry information about the two dimensional distribution of trace gases on a small scale (e.g. tens to hundreds of metres) is highly desirable. An airborne instrument based on imaging Differential Optical Absorption Spectroscopy has been built to map the two dimensional distribution of a series of relevant trace gases including NO 2, HCHO, C2H2O2, H2O, O4, SO2, and BrO on a scale of 100 m. Here we report on the first tests of the novel aircraft instrument over the industrialised South African Highveld, where large variations in NO2 column densities in the immediate vicinity of several sources e.g. power plants or steel works, were measured. The observed patterns in the trace gas distribution are interpreted with respect to flux estimates, and it is seen that the fine resolution of the measurements allows separate sources in close proximity to one another to be distinguished.

Abrupt recent trend changes in atmospheric nitrogen dioxide over the Middle East.

Space observations of the Middle East show that geopolitics and armed conflict have drastically altered air pollution emissions. Nitrogen oxides, released from fossil fuel use and other combustion processes, affect air quality and climate. From the mid-1990s onward, nitrogen dioxide (NO2) has been monitored from space, and since 2004 with relatively high spatial resolution by the Ozone Monitoring Instrument. Strong upward NO2 trends have been observed over South and East Asia and the Middle East, in particular over major cities. We show, however, that a combination of air quality control and political factors, including economical crisis and armed conflict, has drastically altered the emission landscape of nitrogen oxides in the Middle East. Large changes, including trend reversals, have occurred since about 2010 that could not have been predicted and therefore are at odds with emission scenarios used in projections of air pollution and climate change in the early 21st century.

Satellite measurements of formaldehyde from shipping emissions

Satellite measurements of formaldehyde from shipping emissions T. Marbach, S. Beirle, U. Platt, P. Hoor, F. Wittrock, A. Richter, M. Vrekoussis, M. Grzegorski, J. P. Burrows, and T. Wagner Max Planck Institute for Chemistry, Mainz, Germany Institute of Environmental Physics, Heidelberg, Germany Institute of Environmental Physics, Bremen, Germany Center for Ecology and Hydrology, Wallingford, UK Received: 18 March 2009 – Accepted: 16 April 2009 – Published: 30 April 2009 Correspondence to: T. Marbach (marbach@mpch-mainz.mpg.de) Published by Copernicus Publications on behalf of the European Geosciences Union.

SCIAMACHY’s View of the Changing Earth’s Environment

Since August 2002 SCIAMACHY delivers a wealth of high-quality data permitting to study the status of the Earth’s atmosphere. Enhanced concentrations of greenhouse gases are identified as the major source of global warming and their atmospheric concentrations are increasing. SCIAMACHY monitors the most prominent species such as CO2, CH4 and water vapour, the latter including isotope variants. Further anthropogenic impacts on the troposphere occur by emission of reactive trace gases contributing to pollution and affecting air quality. With SCIAMACHY their global, regional and even local signatures can be detected. Long-term analyses document how the emissions of NO2, SO2, HCHO, CHOCHO and CO evolve with time. In addition, the halogen cycle of polar BrO and IO, both of natural origin, is studied. The stratosphere is the layer where public interest in the Earth’s atmosphere has begun to grow with the detection of the ozone hole in the mid-1980s. Until the mid-1990s a steady decrease has been observed in the ozone abundance. The most striking feature is the massive loss of stratospheric ozone over Antarctica during each southern spring. In order to detect possible signs of recovery, SCIAMACHY contributes to the continuous monitoring of the ozone layer, the ozone hole, Polar Stratospheric Clouds (PSC) and species impacting the ozone chemistry such as NO2, OClO and BrO. A much more poorly explored region is the mesosphere and lower thermosphere, which forms the transition between interplanetary space and the terrestrial atmosphere. This region is dominated by extraterrestrial impacts as well as couplings to the lower atmosphere. With SCIAMACHY’s limb viewing capabilities Noctilucent Clouds (NLC) are studied providing insight into generation and depletion mechanisms. At times of strong solar activity, SCIAMACHY measurements reveal how the chemistry of the upper atmosphere is disturbed. By analysis of emission lines in SCIAMACHY spectra the composition of the thermosphere above 100 km can be studied. SCIAMACHY is the first instrument to globally observe the metal layers in the upper mesosphere/lower thermosphere (MLT) region. When applying appropriate retrieval techniques it is meanwhile possible to derive vegetation information over land and phytoplankton characteristics in the oceans from SCIAMACHY data. Finally SCIAMACHY even has proven useful in planetary science by measuring spectra of our solar system neighbour Venus.

Applications of Satellite Observations of Tropospheric Composition

A striking feature of the field of tropospheric composition is the sheer number of chemical species that have been detected and measured with satellite instruments. The measurements have found application both in atmospheric chemistry itself, providing evidence, for example, of unexpected cryochemistry in the Arctic regions, and also in environmental monitoring with, for example, the observed growth in NO2 emissions over eastern Asia. Chapter 8 gives an overview of the utility of satellite observations for measuring tropospheric composition, dealing with each of the many compounds seen in detail. A comprehensive compound by compound table of the many studies performed is a most useful feature.