Annually averaged solar radiation in the McMurdo Dry Valleys, Antarctica has varied by over 20 W m^-2 during the past three decades; however, the drivers of this variability are unknown. Because small differences in radiation are important to water availability and ecosystem functioning in polar deserts, determining the causes are important to predictions of future desert processes. We examine the potential drivers of solar variability and systematically eliminate all but stratospheric sulfur dioxide. We argue that increases in stratospheric sulfur dioxide increase stratospheric aerosol optical depth and decrease solar intensity. Because of the polar location of the McMurdo Dry Valleys (77-78°S) and relatively long solar ray path through the stratosphere, terrestrial solar intensity is sensitive to small differences in stratospheric transmissivity. Important sources of sulfur dioxide include natural (wildfires and volcanic eruptions) and anthropogenic emission.

中文翻译：

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南极洲麦克默多干谷太阳辐射变化的驱动因素。


过去三十年来，南极洲麦克默多干谷的年平均太阳辐射变化超过 20 W m ^-2 ；然而，这种变化的驱动因素尚不清楚。由于辐射的微小差异对于极地沙漠的水供应和生态系统功能很重要，因此确定原因对于预测未来的沙漠过程也很重要。我们研究了太阳变化的潜在驱动因素，并系统地消除了平流层二氧化硫以外的所有物质。我们认为平流层二氧化硫的增加会增加平流层气溶胶的光学深度并降低太阳强度。由于麦克默多干谷 (77-78°S) 的极地位置以及穿过平流层的太阳光线路径相对较长，地面太阳强度对平流层透射率的微小差异很敏感。二氧化硫的重要来源包括自然排放（野火和火山爆发）和人为排放。