返回
A refined statistical cloud closure using double-Gaussian probability density functions
DOI:10.5194/gmd-6-1641-2013.png)
摘要
En 中文
We introduce a probability density function (PDF)-based scheme to parameterize cloud fraction, average liquid water and liquid water flux in large-scale models, that is developed from and tested against large-eddy simulations and observational data. Because the tails of the PDFs are crucial for an appropriate parameterization of cloud properties, we use a double-Gaussian distribution that is able to represent the observed, skewed PDFs properly. Introducing two closure equations, the resulting parameterization relies on the first three moments of the subgrid variability of temperature and moisture as input parameters. The parameterization is found to be superior to a single-Gaussian approach in diagnosing the cloud fraction and average liquid water profiles. A priori testing also suggests improved accuracy compared to existing double-Gaussian closures. Furthermore, we find that the error of the new parameterization is smallest for a horizontal resolution of about 5-20 km and also depends on the appearance of mesoscale structures that are accompanied by higher rain rates. In combination with simple autoconversion schemes that only depend on the liquid water, the error introduced by the new parameterization is orders of magnitude smaller than the difference between various autoconversion schemes. For the liquid water flux, we introduce a parameterization that is depending on the skewness of the subgrid variability of temperature and moisture and that reproduces the profiles of the liquid water flux well.
Keyword:
LARGE-EDDY SIMULATION
NUMERICAL WEATHER PREDICTION
SHALLOW CUMULUS
MESOSCALE VARIABILITY
BOUNDARY-LAYERS
SMALL-SCALE
PARAMETERIZATION
MODEL
CONDENSATION
AUTOCONVERSION
AI总结
对已上传原文的论文进行重点信息的提取,主要内容包括:简要概述、研究摘要、背景介绍、关键亮点、图文解析、展望与总结。
期刊
IF:
4.9
论文数:
4.1K
被引数:
2.4W
机构
引用论文
Applications and Perspectives in Anatomical 3-Dimensional Modelling of the Visible Human with VOXEL-MAN可视人体解剖三维建模中VOXEL-MAN的应用与展望

