Comparison of column ozone retrievals by use of an UV multifilter rotating shadow-band radiometer with those from Brewer and Dobson spectrophotometers

Abstract

The U.S. Department of Agriculture UV-B Monitoring Program measures ultraviolet light at seven wavelengths from 300 to 368 nm with an ultraviolet multifilter rotating shadow-band radiometer (UV-MFRSR) at 25 sites across the United States, including Mauna Loa, Hawaii. Column ozone has been retrieved under all-sky conditions near Boulder, Colorado (40.177 degrees N, 105.276 degrees W), from global irradiances of the UV-MFRSR 332- and 305-nm channels (2 nm FWHM) using lookup tables generated from a multiple-scattering radiative transfer code suitable for solar zenith angles (SZA's) up to 90 degrees. The most significant sources of error for UV-MFRSR column ozone retrievals at SZA's less than 75 degrees are the spectral characterizations of the filters and the absolute calibration uncertainty, which together yield an estimated uncertainty in ozone retrievals of +/-4.0%. Using model sensitivity studies, we determined that the retrieved column ozone is relatively insensitive (<+/-2%) to typical variations in aerosol optical depth, cloud cover, surface pressure, stratospheric temperature, and surface albedo. For 5 months in 1996-1997 the mean ratio of column ozone retrieved by the UV-MFRSR divided by that retrieved by the collocated Brewer was 1.024 and for the UV-MFRSR divided by those from a nearby Dobson was 1.025. The accuracy of the retrieval becomes unreliable at large SZA's of more than 75 degrees as the detection limit of the 305-nm channel is reached and because of overall angular response errors. The UV-MFRSR advantages of relatively low cost, unattended operation, automated calibration stability checks using Langley plots, and minimal maintenance make it a unique instrument for column ozone measurement.

Climatology and trends of surface UV radiation: Survey article

“…They can give accurate measurements of both total ozone and cloud optical depth as well as reasonable estimates of biologically effective UV irradiance (Dahlback, 1996), and are generally easier to characterize and calibrate than broadband UV radiometers (Slusser et al, 1999;Gao et al, 2002). Some 33 stations submit multi-filter radiometer data regularly to the WOUDC.…”

Comparison of total column ozone data from ground‐based MFRSR measurements taken in the southern U.S. region with OMI satellite retrievals

“…[7] The UV-MFRSR has been established as a reliable TCO measurement instrument through comparison studies with Brewer and Dobson spectrophotometers [Slusser et al, 1999;Bigelow and Slusser, 2000;Gao et al, 2001]. The direct-Sun irradiance method is employed to retrieve the TCO and is explained fully by Gao et al [2001], who calculated the total uncertainty in TCO retrievals by the UV-MFRSR instrument to be ±2.0%.…”

“…In this work, we use data from an MFRSR network for comparison with OMI-TOMS measurements as the MFRSR instrument has gained more acceptance from the community of stratospheric ozone researchers [Slusser et al, 1999;McArthur et al, 2003;Min et al, 2004;Goering et al, 2005].…”

Análise Dos Dois Principais Fatores De Decaimento Da Coluna Total De Ozônio Sobre O Sul Da América Do Sul

“…A maior concentração de O 3 está centrada na estratosfera, devido à forte incidência de radiação UV que juntamente com as moléculas de oxigênio existentes nessa camada produzem seu conteúdo (SLUSSER et al, 1999). Apesar de a região tropical ser a maior produtora de ozônio estratosférico, devido à maior incidência de radiação, uma circulação meridional de ozônio estratosférico explica a maior concentração de seu conteúdo na região Antártica, pela circulação Brewer-Dobson (BREWER, 1949;DOBSON, 1968).…”