Spectral retrieval has long been a powerful tool for interpreting planetary remote sensing observations. Flexible, parameterised, agnostic models are coupled with inversion algorithms in order to infer atmospheric properties directly from observations, with minimal reliance on physical assumptions. This approach, originally developed for application to Earth satellite data and subsequently observations of other Solar System planets, has been recently and successfully applied to transit, eclipse and phase curve spectra of transiting exoplanets. In this review, we present the current state-of-the-art in terms of our ability to accurately retrieve information about atmospheric chemistry, temperature, clouds and spatial variability; we discuss the limitations of this, both in the available data and modelling strategies used; and we recommend approaches for future improvement.

中文翻译：

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系外行星大气检索的突出挑战

光谱检索长期以来一直是解释行星遥感观测的有力工具。灵活的、参数化的、不可知的模型与反演算法相结合，以便直接从观测中推断出大气特性，对物理假设的依赖最小。这种方法最初是为应用于地球卫星数据以及随后对其他太阳系行星的观测而开发的，最近已成功应用于凌日系外行星的凌日、日食和相位曲线光谱。在这篇综述中，我们展示了我们准确检索有关大气化学、温度、云和空间变异性信息的能力方面的最新技术；我们在可用数据和使用的建模策略方面讨论了这种限制；