A Tool for Generating Fast k‐Distribution Gas‐Optics Models for Weather and Climate Applications
A Tool for Generating Fast k‐Distribution Gas‐Optics Models for Weather and Climate Applications
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用于生成天气和气候应用的快速 k 分布气体光学模型的工具
DOI：
10.1029/2022ms003033
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发表时间：
2022
影响因子：
6.8
通讯作者：
M. Matricardi
中科院分区：
文献类型：
--
作者：
R. Hogan;M. Matricardi
大气辐射方案最重要的组成部分之一是它对气体光学性质的处理，这不仅决定了对气候预测至关重要的辐射强迫计算的准确性，而且还决定了它的计算成本。本文描述了一个免费的软件工具“ecCKD”，通过根据用户指定的误差容限和需要模拟的温室气体浓度范围，将光谱最佳地划分为伪单色光谱间隔（称为k项），从而生成快速的气体光学模型。生成的模型使用用户指定波段的相关k -分布方法，但也可以生成准确的“全光谱相关k”模型，该模型适用于整个长波或近红外（NIR）部分的光谱。在近红外光谱中，云吸收的大光谱变化通过将光谱中气体光学薄的部分划分为2-6个子波段来表示，而允许光谱中光学厚的部分（云和表面反射率不太重要）的k项跨越整个近红外光谱。候选模型在每个短波和长波中仅使用16和32 k -项，并在晴空和多云剖面上逐行计算进行评估。32期模式能够准确地捕获不同温室气体的辐射强迫，包括CO2浓度的12倍，以及压力低至1pa时的升温速率。
One of the most important components of an atmospheric radiation scheme is its treatment of gas optical properties, which determines not only the accuracy of its radiative forcing calculations fundamental to climate prediction, but also its computational cost. This paper describes a free software tool “ecCKD” for generating fast gas‐optics models by optimally dividing the spectrum into pseudo‐monochromatic spectral intervals (known as k‐terms) according to a user‐specified error tolerance and the range of greenhouse‐gas concentrations that needs to be simulated. The models generated use the correlated k‐distribution method in user‐specified bands, but can also generate accurate “full‐spectrum correlated‐k” models that operate on the entire longwave or near‐infrared (NIR) parts of the spectrum. In the NIR, the large spectral variation in cloud absorption is represented by partitioning the parts of the spectrum where gases are optically thin into 2–6 sub‐bands, while allowing k‐terms for the optically thicker parts of the spectrum (where clouds and surface reflectance are less important) to span the entire NIR spectrum. Candidate models using only 16 and 32 k‐terms in each of the shortwave and longwave are evaluated against line‐by‐line calculations on clear and cloudy profiles. The 32‐term models are able to accurately capture the radiative forcing of varying greenhouse gases including CO2 concentrations spanning a factor of 12, and heating rates at pressures down to 1 Pa.
影响因子：
2.7
作者：
Hogan, Robin J.
通讯作者：
Hogan, Robin J.