Micheletti Maria Isabel, Piacentini Rubén D, Madronich Sasha
Instituto de Fisica Rosario, CONICET-Universidad Nacional de Rosario, Rosario, Argentina.
Photochem Photobiol. 2003 Nov;78(5):456-61. doi: 10.1562/0031-8655(2003)078<0456:sobaur>2.0.co;2.
Biological action spectra are commonly used to assess health and ecosystem responses to increases in spectral ultraviolet (UV) irradiances resulting from stratospheric ozone (O3) 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 O3 column amount. We use a detailed radiative transfer model to calculate the dependence of RAF on the O3 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 approximately 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 O3-related studies can be compromised.
生物作用光谱通常用于评估健康和生态系统对平流层臭氧（O₃）减少导致的光谱紫外线（UV）辐照度增加的响应。对于每个作用光谱，可以计算归一化灵敏度系数（辐射放大因子[RAF]），即大气O₃柱量相对减少时生物活性紫外线辐照度的相对增加量。我们使用详细的辐射传输模型来计算几种常用作用光谱的RAF对O₃柱量和太阳天顶角（因此也隐含地对纬度和季节）的依赖性。使用一个简单的解析模型根据UV-B和UV-A波长范围内作用光谱的半对数斜率来解释结果。我们还表明，如果作用光谱的UV-A部分很显著但被忽略，RAF可能会被大幅高估。这通过几个理想化的作用光谱以及已发表的植物对紫外线照射响应的作用光谱来说明。一般来说，如果作用光谱在大约300 nm以上测量的部分在其灵敏度上跨度小于约两个数量级，估计的RAF可能会出现显著误差，并且在与O₃相关的研究中使用此作用光谱可能会受到影响。
