SORCE contributions to new understanding of global change and solar variability
SORCE contributions to new understanding of global change and solar variability
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DOI：
10.1007/s11207-005-1527-2
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发表时间：
2005-08-01
期刊：
影响因子：
2.8
通讯作者：
Kopp, G
中科院分区：
文献类型：
--
作者：
Lean, J;Rottman, G;Kopp, G
太空时代和过去的一系列经验证据表明，气候对太阳活动有反应。反应机制被认为是直接的表面加热、涉及紫外线辐射和平流层的间接过程以及内部气候系统振荡的调制的某种组合。迄今为止，还没有一种定量的物理描述来解释太阳辐射输出变化的已知幅度和气候对这些变化的敏感性方面的经验证据。再现太阳引起的年代际气候变化需要比大气环流模型允许的更快和更大的反应。太阳引起的平流层变化对气候的间接影响也没有得到充分了解，部分原因是平流层和对流层的垂直耦合存在不确定性。考虑到太阳对工业化前地表温度的影响，需要比当代数据库中存在的辐照度变化更大的辐照度变化，但长期辐照度变化的证据尚不明确。对未来的进展至关重要的是对产生气候强迫的太阳辐射输出变化进行可靠、广泛的观测。在开始连续监测太阳总辐射输出25年后，太阳辐射和气候实验开始了新一代的太阳辐照度测量，其能力大大扩展。相对于历史上的太阳观测，SORCE监测总辐照度和光谱辐照度，显著降低了不确定性，提高了可重复性，特别是在长时间尺度上。光谱覆盖范围扩展到紫外线波长之外，涵盖主导太阳辐射输出的可见光和近红外区域。天基辐照度记录，现在增加了光谱的变化，有利于改善表征磁源的辐照度变化，并检测额外的机制。这一认识为估计过去和未来的辐照度变化提供了科学依据，而这是探测和预测气候变化所必需的。
An array of empirical evidence in the space era, and in the past, suggests that climate responds to solar activity. The response mechanisms are thought to be some combination of direct surface heating, indirect processes involving UV radiation and the stratosphere, and modulation of internal climate system oscillations. A quantitative physical description is, as yet, lacking to explain the empirical evidence in terms of the known magnitude of solar radiative output changes and of climate sensitivity to these changes. Reproducing solar-induced decadal climate change requires faster and larger responses than general circulation models allow. Nor is the indirect climatic impact of solar-induced stratospheric change adequately understood, in part because of uncertainties in the vertical coupling of the stratosphere and troposphere. Accounting for solar effects on pre-industrial surface temperatures requires larger irradiance variations than present in the contemporary database, but evidence for significant secular irradiance change is ambiguous. Essential for future progress are reliable, extended observations of the solar radiative output changes that produce climate forcing. Twenty-five years after the beginning of continuous monitoring of the Sun's total radiative output, the Solar Radiation and Climate Experiment (SORCE) commences a new generation of solar irradiance measurements with much expanded capabilities. Relative to historical solar observations SORCE monitors both total and spectral irradiance with significantly reduced uncertainty and increased repeatability, especially on long time scales. Spectral coverage expands beyond UV wavelengths to encompass the visible and near-IR regions that dominate the Sun's radiative output. The space-based irradiance record, augmented now with the spectrum of the changes, facilitates improved characterization of magnetic sources of irradiance variability, and the detection of additional mechanisms. This understanding provides a scientific basis for estimating past and future irradiance variations, needed for detecting and predicting climate change.