Our next lunch talk:
Will be Tuesday April 2, 2013 at 12:15PM
UMC 353, University of Colorado Boulder
Bring your lunch, the talk starts at about 12:15
Dr. Rebecca Washenfelder,
Research Scientist, National Oceanic and Atmospheric Administration
Chemical and optical properties of organic aerosol
Recent advances in optical spectroscopy have led to new
broadband cavity enhanced spectrometers (BBCES) that combine
high-finesse optical cavities with high-powered LED light sources,
spectrally resolving the light output with a grating spectrometer.
This technique can be used to make sensitive, in situ measurements of
Organic compounds contribute a large fraction of aerosol mass, and
glyoxal has been identified in previous laboratory and field studies
to be one potential source of organic mass. We deployed a BBCES
instrument to measure glyoxal during summer 2010 in Pasadena,
California. We used three methods to quantify the contribution of
glyoxal to aerosol in Los Angeles, and found that it accounts for only
0 - 4% of the secondary organic aerosol mass.
Quantifying the optical properties of aerosols is important to
understand their role in the Earth’s radiative budget. Previous
measurements have indicated that brown carbon aerosol has a
wavelength-dependent absorption that increases in the ultraviolet
spectral region, and recent modeling suggests that this is an
important component of aerosol radiative forcing. We have conducted
recent laboratory and field measurements of aerosol scattering and
absorption in the ultraviolet spectral region to address these issues.
Please fell free to join other Sigma Xi members for lunch on the ground four of the NCAR Mesa Lab at11:30 AM.