Rebecca Washenfelder

Rebecca Washenfelder photo

Research Scientist II

Tropospheric Chemistry

Mailing address:
NOAA ESRL Chemical Sciences Division
325 Broadway, R/CSD7
Boulder, CO 80305 USA

Phone: (303) 497-4810

I am a scientist at the NOAA Earth System Research Laboratory (ESRL), employed through the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado in Boulder. I joined the laboratory in August 2006 as a National Academies Postdoctoral Fellow. I am currently working with Dr. Steve Brown.

The focus of my research is developing new spectroscopic measurements for field studies of atmospheric trace gases and aerosols. During the CalNex 2010 field campaign in Los Angeles, I used broadband cavity enhanced spectroscopy to measure glyoxal (CHOCHO), nitrous acid (HONO), and nitrogen dioxide (NO2).  More recently, I have used the same technique to measure aerosol optical extinction, and developed methods to calculate aerosol refractive indices as a function of wavelength.


B.A., Chemistry, Pomona College, 1999
M.S., Environmental Science and Engineering, California Institute of Technology, 2002
Ph.D., Environmental Science and Engineering, California Institute of Technology, 2006


- Measurement of trace reactive gases and aerosol optical properties using spectroscopic techniques.
- Quantifying the chemical and optical properties of organic aerosol.
- Information about my graduate work: column concentrations of greenhouse gases and the Total Carbon Column Observing Network.

Current Topics

Broadband cavity enhanced spectroscopy (BBCES) is an analytical technique that was first described by Fiedler et al. (2003). This approach uses a broadband light source, optical cavity, and grating spectrometer to acquire spectra with a very long effective absorption pathlength. Spectral fitting methods can be used to retrieve multiple absorbers. I have used this technique for laboratory and field measurements of glyoxal (CHOCHO), nitrous acid (HONO), nitrogen dioxide (NO2), ozone (O3), hydrogen peroxide (H2O2), and aerosol optical extinction.

I am currently focused on methods to determine complex refractive indices of aerosol in the ultraviolet spectral region.  This is important because organic aerosols have been shown to absorb light in this spectral region, which may significantly affect the earth's radiative budget.

Cooperative Institute for Research in Environmental Sciences National Oceanic and Atmospheric Administration

last modified: July 01, 2013