Search Results

You are looking at 1 - 2 of 2 items for :

  • Author or Editor: Andreas Richter x
  • Bulletin of the American Meteorological Society x
  • Refine by Access: All Content x
Clear All Modify Search
Jack Fishman, Kevin W. Bowman, John P. Burrows, Andreas Richter, Kelly V. Chance, David P. Edwards, Randall V. Martin, Gary A. Morris, R. Bradley Pierce, Jerald R. Ziemke, Jassim A. Al-Saadi, John K. Creilson, Todd K. Schaack, and Anne M. Thompson

We review the progress of tropospheric trace gas observations and address the need for additional measurement capabilities as recommended by the National Research Council. Tropospheric measurements show pollution in the Northern Hemisphere as a result of fossil fuel burning and a strong seasonal dependence with the largest amounts of carbon monoxide and nitrogen dioxide in the winter and spring. In the summer, when photochemistry is most intense, photochemically generated ozone is found in large concentrations over and downwind from where anthropogenic sources are largest, such as the eastern United States and eastern China. In the tropics and the subtropics, where photon flux is strong throughout the year, trace gas concentrations are driven by the abundance of the emissions. The largest single tropical source of pollution is biomass burning, as can be seen readily in carbon monoxide measurements, but lightning and biogenic trace gases may also contribute to trace gas variability. Although substantive progress has been achieved in seasonal and global mapping of a few tropospheric trace gases, satellite trace gas observations with considerably better temporal and spatial resolution are essential to forecasting air quality at the spatial and temporal scales required by policy makers. The concurrent use of atmospheric composition measurements for both scientific and operational purposes is a new paradigm for the atmospheric chemistry community. The examples presented illustrate both the promise and challenge of merging satellite information with in situ observations in state-of-the-art data assimilation models.

Full access
Manfred Wendisch, Andreas Macke, André Ehrlich, Christof Lüpkes, Mario Mech, Dmitry Chechin, Klaus Dethloff, Carola Barrientos Velasco, Heiko Bozem, Marlen Brückner, Hans-Christian Clemen, Susanne Crewell, Tobias Donth, Regis Dupuy, Kerstin Ebell, Ulrike Egerer, Ronny Engelmann, Christa Engler, Oliver Eppers, Martin Gehrmann, Xianda Gong, Matthias Gottschalk, Christophe Gourbeyre, Hannes Griesche, Jörg Hartmann, Markus Hartmann, Bernd Heinold, Andreas Herber, Hartmut Herrmann, Georg Heygster, Peter Hoor, Soheila Jafariserajehlou, Evelyn Jäkel, Emma Järvinen, Olivier Jourdan, Udo Kästner, Simonas Kecorius, Erlend M. Knudsen, Franziska Köllner, Jan Kretzschmar, Luca Lelli, Delphine Leroy, Marion Maturilli, Linlu Mei, Stephan Mertes, Guillaume Mioche, Roland Neuber, Marcel Nicolaus, Tatiana Nomokonova, Justus Notholt, Mathias Palm, Manuela van Pinxteren, Johannes Quaas, Philipp Richter, Elena Ruiz-Donoso, Michael Schäfer, Katja Schmieder, Martin Schnaiter, Johannes Schneider, Alfons Schwarzenböck, Patric Seifert, Matthew D. Shupe, Holger Siebert, Gunnar Spreen, Johannes Stapf, Frank Stratmann, Teresa Vogl, André Welti, Heike Wex, Alfred Wiedensohler, Marco Zanatta, and Sebastian Zeppenfeld

Abstract

Clouds play an important role in Arctic amplification. This term represents the recently observed enhanced warming of the Arctic relative to the global increase of near-surface air temperature. However, there are still important knowledge gaps regarding the interplay between Arctic clouds and aerosol particles, and surface properties, as well as turbulent and radiative fluxes that inhibit accurate model simulations of clouds in the Arctic climate system. In an attempt to resolve this so-called Arctic cloud puzzle, two comprehensive and closely coordinated field studies were conducted: the Arctic Cloud Observations Using Airborne Measurements during Polar Day (ACLOUD) aircraft campaign and the Physical Feedbacks of Arctic Boundary Layer, Sea Ice, Cloud and Aerosol (PASCAL) ice breaker expedition. Both observational studies were performed in the framework of the German Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms (AC) project. They took place in the vicinity of Svalbard, Norway, in May and June 2017. ACLOUD and PASCAL explored four pieces of the Arctic cloud puzzle: cloud properties, aerosol impact on clouds, atmospheric radiation, and turbulent dynamical processes. The two instrumented Polar 5 and Polar 6 aircraft; the icebreaker Research Vessel (R/V) Polarstern; an ice floe camp including an instrumented tethered balloon; and the permanent ground-based measurement station at Ny-Ålesund, Svalbard, were employed to observe Arctic low- and mid-level mixed-phase clouds and to investigate related atmospheric and surface processes. The Polar 5 aircraft served as a remote sensing observatory examining the clouds from above by downward-looking sensors; the Polar 6 aircraft operated as a flying in situ measurement laboratory sampling inside and below the clouds. Most of the collocated Polar 5/6 flights were conducted either above the R/V Polarstern or over the Ny-Ålesund station, both of which monitored the clouds from below using similar but upward-looking remote sensing techniques as the Polar 5 aircraft. Several of the flights were carried out underneath collocated satellite tracks. The paper motivates the scientific objectives of the ACLOUD/PASCAL observations and describes the measured quantities, retrieved parameters, and the applied complementary instrumentation. Furthermore, it discusses selected measurement results and poses critical research questions to be answered in future papers analyzing the data from the two field campaigns.

Open access