title: The 1996 North American Interagency Intercomparison of Ultraviolet Monitoring Spectroradiometers.
abstract: Concern over stratospheric ozone depletion has prompted several government agencies in North America to establish networks of spectroradiometers for monitoring solar ultraviolet irradiance at the surface of the Earth. To assess the ability of spectroradiometers to accurately measure solar ultraviolet irradiance, and to compare the results between instruments of different monitoring networks, the third North American Interagency Intercomparison of Ultraviolet Monitoring Spectroradiometers was held June 17-25, 1996 at Table Mountain outside Boulder, Colorado, USA. This Intercomparison was coordinated by the National Institute of Standards and Technology (NIST) and the National Oceanic and Atmospheric Administration (NOAA). Participating agencies were the Environmental Protection Agency; the National Science Foundation; the Smithsonian Environmental Research Center; the Department of Agriculture; and the Atmospheric Environment Service, Canada. The spectral irradiances of participants' calibrated standard lamps were measured at NIST prior to the Intercomparison. The spectral irradiance scales used by the participants agreed with the NIST scale within the combined uncertainties, and for all lamps the spectral irradiance in the horizontal position was lower than that in the vertical position. Instruments were characterized for wavelength uncertainty, bandwidth, stray-light rejection, and spectral irradiance responsivity, the latter with NIST standard lamps operating in specially designed field calibration units. The spectral irradiance responsivity demonstrated instabilities for some instruments. Synchronized spectral scans of the solar irradiance were performed over several days. Using the spectral irradiance responsivities determined with the NIST standard lamps, the measured solar irradiances had some unexplained systematic differences between instruments.
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899-0001 USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Early
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899-0001 USA.
authors.forename: Ambler
authors.initials: A
authors.lastname: Thompson
authors.affiliation: National Institute of Standards and Technology, Gaithersburg, MD 20899-0001 USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Johnson
authors.affiliation: National Oceanic and Atmospheric Administration, R/E/ARx1, 325 Broadway, Boulder, CO 80303 USA.
authors.forename: John
authors.initials: J
authors.lastname: DeLuisi
authors.affiliation: National Oceanic and Atmospheric Administration, R/E/ARx1, 325 Broadway, Boulder, CO 80303 USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Disterhoft
authors.affiliation: Atmospheric Environment Service, Environment Canada, 4905 Dufferin Street, Toronto, ON M3H 5T4, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Wardle
authors.affiliation: Atmospheric Environment Service, Environment Canada, 4905 Dufferin Street, Toronto, ON M3H 5T4, Canada.
authors.forename: Edmund
authors.initials: E
authors.lastname: Wu
authors.affiliation: Dept. of Physics and Astronomy, University of Georgia, Athens, GA 30602 USA.
authors.forename: Wanfeng
authors.initials: W
authors.lastname: Mou
authors.affiliation: Biospherical Instruments Inc., 5340 Riley Street, San Diego, CA 92110-2621 USA.
authors.forename: James
authors.initials: J
authors.lastname: Ehramjian
authors.affiliation: Biospherical Instruments Inc., 5340 Riley Street, San Diego, CA 92110-2621 USA.
authors.forename: John
authors.initials: J
authors.lastname: Tusson
authors.affiliation: Biospherical Instruments Inc., 5340 Riley Street, San Diego, CA 92110-2621 USA.
authors.forename: Tanya
authors.initials: T
authors.lastname: Mestechkina
authors.affiliation: Yankee Environmental Systems, Inc., Airport Industrial Park Turner Falls, MA 01376 USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Beaubian
authors.affiliation: USDA UV-B Radiation Monitoring Program, Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 880523, USA.
authors.forename: James
authors.initials: J
authors.lastname: Gibson
authors.affiliation: Smithsonian Environmental Research Center of the Smithsonian Institution, P.O. Box 28, Edgewater, MD 21037 USA.
authors.forename: Douglass
authors.initials: D
authors.lastname: Hayes
keywords: environmental monitoring; intercomparison; solar ultraviolet; spectroradiometers