论文标题
使用颜色可变性在外地球上表面组成的全局映射
Global Mapping of the Surface Composition on an Exo-Earth using Color Variability
论文作者
论文摘要
直接成像的行星的光度变化包含有关行星表面的地理和光谱的信息。我们提出了一种新型技术，该技术将空间和光谱信息从多波段反射光曲线中解散。这将使我们能够构成行星表面组成的二维图，除了独立的表面成分数量外，没有事先假设。我们通过使用单纯形体积最小化方法概括了非负矩阵分解（NMF），解决了自旋轨道层析成像和光谱脉冲的统一反问题。我们在玩具无云的地球上评估了我们的方法，并观察到新方法可以准确检索地理和光谱成分。此外，正如深空气候观测站（DSCOVR）所观察到的那样，我们的方法也应用于地球的实际颜色变异性。检索到的地图明确描述了地球的实际地理位置和无混合的光谱捕获海洋，大陆和云的特征。应该指出的是，由复制大陆组成的两个未混合光谱类似于土壤和植被。
Photometric variation of a directly imaged planet contains information on both the geography and spectra of the planetary surface. We propose a novel technique that disentangles the spatial and spectral information from the multi-band reflected light curve. This will enable us to compose a two-dimensional map of the surface composition of a planet with no prior assumption on the individual spectra, except for the number of independent surface components. We solve the unified inverse problem of the spin-orbit tomography and spectral unmixing by generalizing the non-negative matrix factorization (NMF) using a simplex volume minimization method. We evaluated our method on a toy cloudless Earth and observed that the new method could accurately retrieve the geography and unmix spectral components. Furthermore, our method is also applied to the real-color variability of the Earth as observed by Deep Space Climate Observatory (DSCOVR). The retrieved map explicitly depicts the actual geography of the Earth and unmixed spectra capture features of the ocean, continents, and clouds. It should be noted that, the two unmixed spectra consisting of the reproduced continents resemble those of soil and vegetation.
