The incorporation of the Tripleclouds concept into the <i>&delta;</i>-Eddington two-stream radiation scheme: solver characterization and its application to shallow cumulus clouds

doi:10.5194/acp-2020-334

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-334
	*The incorporation of the Tripleclouds concept into the delta-Eddington two-stream radiation scheme: solver characterization and its application to shallow cumulus clouds*
	Nina Črnivec and Bernhard Mayer
	2020-04-30
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	The treatment of unresolved cloud–radiation interactions in weather and climate models has considerably improved over the recent years, compared to conventional plane-parallel radiation schemes, which previously persisted in these models for multiple decades. One such improvement is the state-of-the-art Tripleclouds radiative solver, which has two cloudy and one cloud-free region in each vertical model layer and is thereby capable of representing cloud horizontal inhomogeneity. Inspired by the Tripleclouds concept, primarily introduced by Shonk and Hogan (2008), we incorporated a second cloudy region into the widely employed δ-Eddington two-stream method with maximum-random overlap assumption for partial cloudiness. The inclusion of another cloudy region in the two-stream framework required an extension of vertical overlap rules. While retaining the maximum-random overlap for the entire layer cloudiness, we additionally assumed the maximum overlap of optically thicker cloudy regions in pairs of adjacent layers. This extended overlap formulation implicitly places the optically thicker region towards the interior of the cloud, which is in agreement with the core-shell model for convective clouds. The method was initially applied on a shallow cumulus cloud field, evaluated against a three-dimensional benchmark radiation computation. Different approaches were used to generate a pair of cloud condensates characterizing the two cloudy regions, testing various condensate distribution assumptions along with global cloud variability estimate. Regardless of the exact condensate setup, the radiative bias in the vast majority of Tripleclouds configurations was considerably reduced compared to the conventional plane-parallel calculation. Whereas previous studies employing the Tripleclouds concept focused on researching the top-of-the-atmosphere radiation budget, the present work pioneeringly applies the Tripleclouds to atmospheric heating rate and net surface flux. The Tripleclouds scheme was implemented in the comprehensive libRadtran radiative transfer package and can be utilized to further address key scientific issues related to unresolved cloud-radiation interplay in coarse-resolution atmospheric models.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/248868
专题	地球科学
推荐引用方式 GB/T 7714	Nina Črnivec and Bernhard Mayer. The incorporation of the Tripleclouds concept into the delta-Eddington two-stream radiation scheme: solver characterization and its application to shallow cumulus clouds[J]. Atmospheric Chemistry and Physics,2020.
APA	Nina Črnivec and Bernhard Mayer.(2020).The incorporation of the Tripleclouds concept into the δ-Eddington two-stream radiation scheme: solver characterization and its application to shallow cumulus clouds.Atmospheric Chemistry and Physics.
MLA	Nina Črnivec and Bernhard Mayer."The incorporation of the Tripleclouds concept into the δ-Eddington two-stream radiation scheme: solver characterization and its application to shallow cumulus clouds".Atmospheric Chemistry and Physics (2020).