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Sensitivity of Biologically Active UV Radiation to Stratospheric Ozone Changes: Effects of Action Spectrum Shape and Wavelength Range ¶
Author(s) -
Micheletti María Isabel,
Piacentini Rubén D.,
Madronich Sasha
Publication year - 2003
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2003)0780456sobaur2.0.co2
Subject(s) - action spectrum , irradiance , spectral line , solar zenith angle , ultraviolet , wavelength , ozone layer , ozone , atmospheric sciences , radiation , radiative transfer , latitude , zenith , ozone depletion , sensitivity (control systems) , sunlight , environmental science , chemistry , stratosphere , physics , optics , meteorology , photochemistry , astronomy , electronic engineering , engineering
Biological action spectra are commonly used to assess health and ecosystem responses to increases in spectral ultraviolet (UV) irradiances resulting from stratospheric ozone (O 3 ) reductions. For each action spectrum, a normalized sensitivity coefficient (the radiation amplification factor [RAF]) can be calculated as the relative increase in biologically active UV irradiance for a given relative decrease in the atmospheric O 3 column amount. We use a detailed radiative transfer model to calculate the dependence of RAF on the O 3 column amount and the solar zenith angle (and, therefore, implicitly on latitude and season) for several commonly used action spectra. A simple analytical model is used to interpret the results in terms of the semilogarithmic slope of the action spectra in the UV‐B and UV‐A wavelength ranges. We also show that RAF may be overestimated substantially if the UV‐A portion of an action spectrum is significant but is neglected. This is illustrated using several idealized action spectra as well as published action spectra for plant responses to UV irradiation. Generally, if the portion of an action spectrum measured longward of ∼300 nm spans less than about two orders in magnitude in its sensitivity, significant errors in the estimated RAF may ensue, and the use of this action spectrum in O 3 ‐related studies can be compromised.