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首页> 外文期刊>Astrobiology >Detectability of planetary characteristics in disk-averaged spectra II: Synthetic spectra and light-curves of earth
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Detectability of planetary characteristics in disk-averaged spectra II: Synthetic spectra and light-curves of earth

机译：圆盘平均光谱中行星特征的可探测性II：地球的合成光谱和光曲线

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Spatially and spectrally resolved models were used to explore the observational sensitivity to changes in atmospheric and surface properties and the detectability of surface biosignatures in the globally averaged spectra and light-curves of the Earth. Compared with previous efforts to characterize the Earth using disk-averaged models, a more comprehensive and realistic treatment of the surface and atmosphere was taken into account here. Our results are presented as a function of viewing geometry and phases at both visibleear-infrared (0.5-1.7 M,m) and mid-infrared (5-25 mu m) wavelength ranges, applicable to the proposed NASA-Terrestrial Planet Finder visible coronagraph and mid-infrared interferometer and to the ESA-Darwin mission architectures. Clouds can change the thermal emission by as much as 50% compared with the cloud-free case and increase the visible albedo by up to 500% for completely overcast cases at the dichotomy phase. Depending on the observed phase and their distribution and type, clouds can also significantly alter the spectral shape. Moreover, clouds impact the detectability of surface biosignatures in the visible wavelength range. Modeling the disk-averaged sensitivity to the "red-edge," a distinctive spectral signature of vegetation, showed that Earth's land vegetation could be seen in disk-averaged spectra, even with cloud cover, when the signal was averaged over the daily time scale. We found that vegetation is more readily discriminated from clouds at dichotomy (50% illumination) rather than at full phase. The detectability of phytoplankton was also explored, but was found to be more difficult to detect in the disk-average than land vegetation.
机译：使用空间和光谱解析模型来探索对大气和表面特性变化的观测敏感性，以及地球平均光谱和地球光曲线中表面生物特征的可检测性。与以前使用磁盘平均模型表征地球的努力相比，此处考虑了对表面和大气的更全面，更实际的处理。我们的结果是在可见/近红外（0.5-1.7 M，m）和中红外（5-25μm）波长范围内查看几何形状和相位的函数，适用于建议的NASA-Terrestrial Planet Finder可见日冕仪和中红外干涉仪以及ESA-达尔文任务架构。与没有云的情况相比，云可以使热辐射变化多达50％，在二分法阶段，对于完全阴云密布的情况，云的可见反照率最多可以增加500％。根据观察到的相位及其分布和类型，云还可以显着改变光谱形状。此外，云影响可见光范围内表面生物特征的可检测性。对磁盘平均对“红边”（植被的独特光谱特征）的敏感性进行建模，结果表明，当在每日时间范围内对信号进行平均时，即使在有云层覆盖的情况下，也可以在磁盘平均光谱中看到地球的陆地植被。我们发现，在二分法（50％照度）下，而不是在整个阶段，植被更容易与云区分开。还探讨了浮游植物的可检测性，但发现在圆盘平均值上比陆地植被更难检测。

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