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Aerosol in the Arctic Summertime: Sources, Impacts, and Melting Sea

The 26th Annual Harold I Schiff Lecture Faculty of Science: Presented by Prof. Jon Abbatt, Department of Chemistry, University of Toronto

Date: Wednesday, September 13, 2017
Time: 2:30 PM
Where: 320 Norman Bethune College, York University

Abstract:  As part of a large NSERC-funded network project, NETCARE, field measurements were made in the Arctic in the summer of 2014 to investigate the nature of aerosol in the high Canadian Arctic.  Our goal was to study the fundamental processes that control the size, abundance, and composition of Arctic aerosol particles in light of a rapidly changing Arctic environment:  Will melting sea ice affect Arctic aerosol and clouds?  To address this question, measurements were made from both the Alfred Wegener Institute (AWI) POLAR6 aircraft and the CGCS Amundsen Icebreaker.  A consistent story arose wherein a biologically active ocean provides a source of volatile gases to the atmosphere that are oxidized to promote both new particle formation and growth in this cool, pristine environment.  Under specific conditions, the numbers of cloud condensation nuclei increase with ensuing effects on cloud droplets.  The summer environment will be contrasted against the much better understood character of the aerosol in the Arctic springtime, i.e. during the period of Arctic Haze.  In particular, NETCARE also made measurements in the spring of 2015, adding to our understanding of the importance of long-range transport and different depositional processes in controlling aerosol abundance during this time period.  The work to be presented reflects the combined efforts of a great number of NETCARE personnel and collaborators.  Especially important were scientific, financial and logistical contributions from Environment and Climate Change Canada, the Department of Fisheries and Oceans, AWI, and a number of foreign collaborators

 


The 25th Annual Harold I Schiff Lecture Faculty of Science: Presented by Prof. Dr. Ulrich Platt

Institute of Environmental Physics
Heidelberg University
Quantification of Volcanic Gas Emission by Optical Spectroscopy - How and Why

Thursday, June 16, 2016, 2:30 PM
103 Life Science Bldg.
York University

Prof. Dr. Ulrich Platt

Prof. Dr. Ulrich Platt


Abstract
: Volcanoes play an enormous role for the Earth system and for our atmosphere. Therefore, volcanic gas emissions are studied not only out of scientific curiosity. In addition to their influence on the atmosphere composition and emission rate of volcanic gases are a window to processes occurring in the Earth’s interior, also volcanic eruptions forecast can be improved by measuring variations of gas emissions    ratios e.g. CO2/SO2 or BrO/SO2. In recent years spectroscopic quantification of gas emissions from volcanoes and other sources made enormous progress. In particular passive spectroscopic approaches observing volcanic gases based on their observation of scattered sun-light in the ultra-violet (UV) spectral range evolved from an art to mature techniques. For instance UV spectrometers form the Continue reading


The 24th Annual Harold I Schiff Lecture Faculty of Science: Presented by Steven S Brown

NOAA Earth System Research Laboratory
and Department of Chemistry, University of Colorado

The Atmospheric Chemistry of Winter

Thursday, May 28, 2015, 2:30 PM

103 Life Science Bldg.
York University

Abstract: The study of lower atmospheric chemistry, at least at northern mid-latitudes where a large fraction of the world’s population resides, has largely been a story of summertime phenomena. Rapid, summertime photochemical oxidation converts primary emissions into secondary pollutants, such as ozone and aerosols, in regions very near the emission sources, leading to significant impacts on air quality and human health. Winter oxidative processes tend to be much slower, allowing for wider dispersion of primary pollutants and generally weaker air quality impacts in the immediate vicinity of source regions. Yet there remain interesting and important chemical cycles that are Continue reading


23rd Annual Harold I Schiff Lecture Faculty of Science: Prof. Dr. habil Astrid Kiendler-Scharr

23rd Annual Harold Schiff Lecturer, Dr. Prof. Habil Astrid Kiendler-Scharr

23rd Annual Harold Schiff Lecturer, Dr. Prof. Habil Astrid Kiendler-Scharr

Speaker: Prof. Dr. Habil Astrid Kiendler-Scharr

Title: Chemistry Climate Interactions: Biogenic Emissions and their Contribution to Secondary Organic Aerosol

Date: October 31, 2013, 2:30 PM

Venue: 103 Life Science Building

Abstract:   Atmospheric aerosols impact climate directly by scattering and absorbing solar radiation and indirectly by acting as ice and cloud condensation nuclei. Secondary organic aerosols (SOA) comprise an important component of atmospheric aerosols. Biogenic volatile organic compounds (BVOC) emitted by vegetation are a major source of SOA. It is known that BVOC emissions depend on climate, specifically on temperature and light. Therefore it is to be expected that a chemistry-climate interaction exists, in which climate change induces changes in BVOC emissions and thereby SOA formation, which feeds back to climate. The presentation details the state of the art knowledge on biogenic SOA and its climate relevance. The question whether climate induced changes in biogenic SOA formation may attenuate or amplify climate change is addressed based on experiments conducted in the Jülich Plant Atmosphere Chamber. Brochure - Y-File

http://www.youtube.com/watch?v=NWaf5T4ThTY&feature=youtu.be