Long‐term Variations in Ultraviolet Sunlight Reaching the Biosphere: . Calculations for the Past Three Decades

Frederick, John E.; Haywood, E. K.

doi:10.1111/j.1751-1097.1991.tb02090.x

Cited by 25 publications

(8 citation statements)

References 13 publications

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“…7 While there have been numerous studies 8 -10 exploring the supposed increase in surface UV radiation resulting from stratospheric ozone decline, 11 none have consistently observed any increasing longterm trend. 12 Experimental observations have indicated that random variability in the attenuating properties of the troposphere will obscure the effect of stratospheric ozone trends. 13 Surface values of UV radiation can be derived from satellite measurements 14 -17 and provide global coverage and the nearly continuous monitoring needed for longterm trend analysis.…”

Section: Introductionmentioning

confidence: 99%

Daily Surface UV Exposure and Its Relationship to Surface Pollutant Measurements

Barnard

Saxena

Wenny

et al. 2003

Journal of the Air & Waste Management Association

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For the past 30 years, the stratospheric ozone layer has decreased in the Northern Hemisphere. The main effect of this ozone decrease was an expected increase in the UV radiation at the Earth's surface, but there has been no clear evidence of an increasing urban trend in surface UV. This study shows that specific air pollutants can reduce the increased surface levels of UV radiation and offers an explanation for why the expected surface UV increases have not been observed, especially in urban regions.A U.S. Environmental Protection Agency (EPA) UV monitoring site at the University of California at Riverside combined with air pollution data from a site operated by the California Air Resources Board in Rubidoux, CA, provided the basis of this study. The 1997 South Coast Ozone Study (SCOS-97) provided three key ingredients: black carbon, PM 10 concentrations, and collocated radiometric measurements. The Total Ozone Mapping Spectrometer (TOMS) satellite data were used to provide the stratospheric ozone levels that were included in the statistical model. All of these input parameters would be used to test this study's hypothesis: the expected increase of surface UV radiation, caused by decreases in stratospheric ozone, can be masked by increases in anthropogenic emissions. The values for the pollutants were 7:00 a.m.-5:00 p.m. averages of the instrument's values taken during summer 1997.A statistical linear regression model was employed using the stratospheric ozone, black carbon, PM 10 , and surface ozone concentrations, and the sin (⌰) and cos (⌰). The angle ⌰ is defined by ⌰ ϭ 2 (Julian date/365). This model obtained a coefficient of determination of 0.94 with an uncertainty level (p value) of less than 0.3% for all of the variables in the model except ground-level ozone. The final model, regressed against a data set from a remote, western North Carolina site, resulted in a coefficient of determination of 0.92. The model shows that black carbon can reduce the Diffey-weighted UV levels that reach the surface by as much as 35%, depending on the season.

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Section: Introductionmentioning

confidence: 99%

Daily Surface UV Exposure and Its Relationship to Surface Pollutant Measurements

Barnard

Saxena

Wenny

et al. 2003

Journal of the Air & Waste Management Association

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“…Decreased levels of ozone in the stratosphere from organochlorine contamination are resulting in higher levels of UV-B radiation reaching the surface of the earth (Frederick, 1990;Frederick et al, 1991;Kerr and McElroy, 1993). Within the UV-B spectral region, the relative enhancement in irradiance resulting from ozone depletion is disproportionately greater at shorter wavelengths (Caldwell et al, 1989).…”

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confidence: 99%

In Vivo Photomodification of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Holoenzyme by Ultraviolet-B Radiation (Formation of a 66-Kilodalton Variant of the Large Subunit)

et al. 1995

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lncreased levels of solar ultraviolet (290-320 nm) (UV-B) radiation could have profound effects on plant proteins because the aromatic amino acids in proteins absorb strongly i n this spectral region. We have investigated the effects of UV-B radiation on plant proteins and have observed a nove1 66-kD protein. This product was formed i n vivo when Brassica napus 1. plants grown for 21 d in 65 pmol m-* s-' photosynthetically active radiation were subsequently exposed to 65 pmol m-' s-' photosynthetically active radiation plus UV-B radiation (1.5 pmol m-' s-'). l h e protein appeared after 4 h of UV-B irradiation and accumulated during the next 16 h in UV-B. The 66-kD protein cross-reacted with an antiserum against the ribulose-1,s-bisphosphate carboxylase/oxygenase (Rubisco) holoenzyme. Analysis of soluble leaf proteins revealed that the 66-kD product had a number of isoforms corresponding closely to those of the large subunit of Rubisco (LSU). Partia1 proteolytic digests of the LSU and the 66-kD protein resulted in an equivalent pattern of protein fragments, leading to the conclusion that the 66-kD protein was a photomodified form of the LSU. A similar high molecular m a s variant of Rubisco was observed in soluble protein extracts from leaves of tomato (Lycopersicon esculentum), tobacco (Nicotiana tabacum), and pea (Pisum sativum L.) plants treated in vivo with UV-B, suggesting that it might be a common product, at least among C, plants. It is interesting that the 66-kD product appears to be generated after incorporation of the LSU into holoenzyme complexes. This conclusion was drawn from two lines of evidence. First, the LSU variant co-purified with holoenzyme complexes isolated by nondenaturing polyacrylamide gel electrophoresis. Second, a UV-B-specific 66-kD protein did not accumulate in a tobacco mutant that synthesizes the Rubisco subunits but does not assemble them into normal holoenzyme complexes.

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“…In contrast, model studies and measurements [Justus, 1992] show that the TUVR response to ozone change is very small (less than 0.2% per 1% change in ozone). Therefore the downward trend of RB irradiance in Figure 1 (by about 10%) is too large (and the upward TUVR trend in Figure 2 is much too large) to be attributed to expected global or regional changes in total ozone column over the study period [Madronich, 1992;Frederick et al, 1991]. It should be noted here that the word "trend" is used synonymously with "year-to-year variations over the 4-year study period."…”

Section: Figure 2 Presents the Rb/global Ratios Ofmentioning

confidence: 99%

Temporal trends in surface irradiance at ultraviolet wavelengths

Justus¹,

Murphey²

1994

J. Geophys. Res.

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To clarify recent, conflicting results about temporal trends in surface ultraviolet (UV) irradiance, a study was undertaken of UVB (280–320 nm) and UVA (320–400 nm) at Atlanta, Georgia, from 1980–1984. Results indicate that, while Robertson‐Berger (UVB) “RB” meter readings decreased about 10% over the period, Eppley “TUVR” (UVA) readings increased about the same amount. These trends appear to be due not to changes in ozone or cloud cover, but to real effects on the RB data from changes in aerosol concentrations, and to calibration drift of the TUVR sensor. Implications of these results for long‐term monitoring of UV radiation are discussed.

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Long‐term Variations in Ultraviolet Sunlight Reaching the Biosphere: . Calculations for the Past Three Decades

Cited by 25 publications

References 13 publications

Daily Surface UV Exposure and Its Relationship to Surface Pollutant Measurements

Daily Surface UV Exposure and Its Relationship to Surface Pollutant Measurements

In Vivo Photomodification of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Holoenzyme by Ultraviolet-B Radiation (Formation of a 66-Kilodalton Variant of the Large Subunit)

Temporal trends in surface irradiance at ultraviolet wavelengths

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