Spectrally resolved comparison of TOMS estimates of surface UV irradiances with those of ground-based measurements at time of overpass

Michael G. Kimlin; Thomas E. Taylor; Jay R. Herman; John E. Rives; Blake Cannon; Richard Stephen Meltzer

doi:10.1117/12.466187

1 July 2003 Spectrally resolved comparison of TOMS estimates of surface UV irradiances with those of ground-based measurements at time of overpass

Michael G. Kimlin, Thomas E. Taylor, Jay R. Herman, John E. Rives, Blake Cannon, Richard Stephen Meltzer

Author Affiliations +

Proceedings Volume 4896, Ultraviolet Ground- and Space-based Measurements, Models, and Effects II; (2003) https://doi.org/10.1117/12.466187
Event: Third International Asia-Pacific Environmental Remote Sensing Remote Sensing of the Atmosphere, Ocean, Environment, and Space, 2002, Hangzhou, China

Abstract

Most comparisons of TOMS estimates of surface UV irradiation with measured values from ground-based instruments have indicated a bias of the TOMS estimates toward larger values. A portion of this bias results from absolute uncertainties in the ground-based instruments. The comparison reported here is based on ground-based data from four sites in the UGA/EPA Brewer network. The raw data from the ground-based instruments has been corrected for (1) stray light rejection, (2) the cosine errors associated with the full sky diffuser, (3) the temperature dependence of the response of the instruments and (4) the temporal variation in the instrument response reducing the estimated errors of the absolute irradiance values of each spectral measurement to < ±7%. Comparisons of TOMS with the surface measurements are performed both at spectrally resolved wavelengths at the time of overpass and for erythemally-weighted daily-integrated doses. These comparisons are made for all days and for clear-sky days only. The comparisons are carried out using both linear regressions of scatter plots of the two sets of data and for mean differences with respect to both TOMS and the Brewer measurements. It is found that spectrally resolved comparisons suffer from inconsistencies at some of the sites that are believed to result from wavelength uncertainties in the Brewer; they are therefore of more limited use than wavelength integrated data. A comparison based on daily-integrated doses shows only a small positive TOMS bias (4%) for clear-sky days with a somewhat larger bias (8%) for data taken from all days.

Citation Download Citation

Michael G. Kimlin, Thomas E. Taylor, Jay R. Herman, John E. Rives, Blake Cannon, and Richard Stephen Meltzer "Spectrally resolved comparison of TOMS estimates of surface UV irradiances with those of ground-based measurements at time of overpass", Proc. SPIE 4896, Ultraviolet Ground- and Space-based Measurements, Models, and Effects II, (1 July 2003); https://doi.org/10.1117/12.466187

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available