The Solar Radiation Environment of Sites at High Southern Latitudes

南半球高纬度地区的生物过程与阳光的供应密切相关。可见光波长的太阳辐射为光合作用提供能量，而紫外线辐射则可起到抑制作用，尽管其影响程度仍有争议。在过去十年中，由于春季大气臭氧水平大幅下降，太阳紫外线辐照度随之增加，人们的注意力集中在南方高纬度地区。该研究项目将采用数据分析和数值模拟相结合的方法，研究导致南半球高纬度地区紫外线和可见光辐射环境变化的主要因素。该项目将利用国家科学基金会极地紫外线辐射网络对太阳紫外线辐射和可见光辐照度的长期地面测量，该网络的站点位于南极洲的麦克默多站、帕尔默站和南极站以及阿根廷的乌斯怀亚站。最早的这些数据集始于1988年，此后数据收集一直在继续，没有大的中断。汇编将包括每月综合辐照度、一个月内的短期变化信息以及数据集持续期间的趋势。报告的辐照度将基于几个生物加权函数以及选定的紫外和可见光离散波长。需要处理的科学专题包括：出现异常大的紫外线辐照度的频率和在数据集期间这种频率的变化;臭氧变化和云量变化对紫外线辐射环境年际变化的相对影响;与多云天空有关的衰减对波长的依赖性。这些分析不仅对大气科学界有价值，而且对研究紫外线辐射对生物过程影响的生物学家和生态学家也有价值。

Biological processes at high latitudes of the Southern Hemisphere are closely coupled to the availability of sunlight. Solar radiation in the visible wavelengths provides the energy for photosynthesis while the ultraviolet (UV) radiation can act as an inhibitor, although the magnitude of the effects are subject to debate. Over the past decade, attention has focused on high southern latitudes due to the large decline in springtime atmospheric ozone levels and the accompanying increases in solar UV irradiance. This research project will address the major factors which lead to variability in the UV and visible radiation environment at high southern latitudes using a combination of data analysis and numerical modeling. The project will utilize long-term, ground-based measurements of solar UV radiation and visible irradiance from the NSF Polar UV Radiation network, with sites located at McMurdo, Palmer and South Pole Stations, Antarctica and Ushuaia, Argentina. The earliest of these data sets began in 1988 and data collection has continued without major interruption since. The compilation will include monthly-integrated irradiances, information of short-term variability within a month, and trends over the duration of the data sets. The reported irradiances will be based on several biological weighting functions as well as selected discrete wavelengths in the ultraviolet and visible. Scientific topics to be addressed include the frequency of occurrence of unusually large UV irradiances and the change in this frequency over the duration of the data sets, the relative contributions of changes in ozone and changes in cloudiness to interannual variability in the UV radiation environment and the wavelength dependence of the attenuation associated with cloudy skies. Not only will the analyses have value to those in the atmospheric sciences community, the data will be summarized in a form valuable to biologists and ecologists studying the effects of UV radiation on biological processes.