论文标题

预先计算的相关-K系数的光谱套筒

Spectral binning of precomputed correlated-k coefficients

论文作者

Leconte, Jérémy

论文摘要

随着执行准确的辐射转移计算所需的光谱线列表列表的重大增加,传播准确的辐射数据几乎与计算它一样多。考虑到许多行星科学应用仅在寻找供暖率或中低分辨率光谱,以准确且灵活的方式以计算和存储成本的一小部分启用此类计算的方法都是非常有价值的。由于许多原因,相关的K方法已经变得非常流行。它的主要弱点是缺乏适应预先计算的K-Coeffictions的光谱网格/分辨率的方法,因此很难分发适合许多不同应用程序的通用数据库。当前,大多数用户仍然需要使用相关行列表或高分辨率横截面的逐线传输代码来计算所需分辨率的k-coeff桌。在这项工作中,我们证明可以将预先计算的K-Coeffictions纳入较低的光谱分辨率,而无需任何其他假设,并在实践中显示如何进行。然后,我们证明该封装程序不会引入准确性的任何重大损失。在此过程中,我们量化了这种方法如何与采样横截面方法相比。这通过向用户提供中分辨率的K-Coefflife桌子提供了一条新的途径,以提供准确的辐射转移数据,这些桌子以后可以随后可以随时定制这些桌子的需求。为了帮助完成这一最后一步,我们简要介绍了Exo_k,这是一个开放式,开源的Python库,旨在以简单且有效的方式处理,量身定制和使用许多不同格式的K-coeffity和cross截面表。

With the major increase in the volume of the spectroscopic line lists needed to perform accurate radiative transfer calculations, disseminating accurate radiative data has become almost as much a challenge as computing it. Considering that many planetary science applications are only looking for heating rates or mid-to-low resolution spectra, any approach enabling such computations in an accurate and flexible way at a fraction of the computing and storage costs is highly valuable. For many of these reasons, the correlated-k approach has become very popular. Its major weakness has been the lack of ways to adapt the spectral grid/resolution of precomputed k-coefficients, making it difficult to distribute a generic database suited for many different applications. Currently, most users still need to have access to a line-by-line transfer code with the relevant line lists or high-resolution cross sections to compute k-coefficient tables at the desired resolution. In this work, we demonstrate that precomputed k-coefficients can be binned to a lower spectral resolution without any additional assumptions, and show how this can be done in practice. We then show that this binning procedure does not introduce any significant loss in accuracy. Along the way, we quantify how such an approach compares very favorably with the sampled cross section approach. This opens up a new avenue to deliver accurate radiative transfer data by providing mid-resolution k-coefficient tables to users who can later tailor those tables to their needs on the fly. To help with this final step, we briefly present Exo_k, an open-access, open-source Python library designed to handle, tailor, and use many different formats of k-coefficient and cross-section tables in an easy and computationally efficient way.

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