双月刊

ISSN 1006-9895

CN 11-1768/O4

η坐标系下假不可压大气模式动力框架改进
DOI:
作者:
作者单位:

中国科学院大气物理研究所

作者简介:

通讯作者:

基金项目:


Improving the dynamic core of a pseudo-incompressible model in the η coordinate
Author:
Affiliation:

Institute of Atmospheric Physics, Chinese Academy of Sciences

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
    摘要:

    发展高分辨区域中尺度天气预报模式是改进暴雨落区预报的一个重要途径。区域中尺度模式空间分辨率达到100米,对当前计算资源提出了严峻挑战。一种可行的解决方案是发展滤除声波的模式替代全弹性模式。滤除声波的模式可以使用较大的时间步长积分,能显著提高积分效率。我们在2018年利用一种声波滤除理论—假不可压理论,初步在地形追随质量坐标系(η坐标系)下建立了假不可压模式。数值试验表明模式的结果是合理可信的,然而关键问题是没有滤除声波。本文我们改进了假不可压模式,建立新的假不可压模式干动力框架。新的动力框架控制方程中最为关键的改进是使用椭圆方程求解扰动气压,理论上保证了声波的滤除。新建立的动力框架在数值求解方案方面的改进在于时间积分格式不再依赖时步分裂算法。对比改进的假不可压模式和WRF模式的干热泡对流数值试验结果,发现假不可压模式获得了与WRF模式相似的动力场和热力场分布,且模拟的气压扰动时间序列平滑,说明声波已被滤除,相比2018版本的假不可压模式,这是较大的改进。

    Abstract:

    The development of high-resolution mesoscale weather forecast numerical models is an important way to improve the forecast of torrential rain. Regional mesoscale models, with a spatial resolution to 100m, pose great challenges to current computational resources. A feasible solution is to develop soundproof models to replace those fully compressible models. Soundproof models permit relatively larger time steps, improving the integration efficiency significantly. We developed a test version of a pseudo-incompressible model in a terrain-following mass-based coordinate (η coordinate), based on a sound-proof theory namely the pseudo-incompressible theory in 2018. Numerical tests indicate the results from the model are reliable. However, a key issue is the acoustic wave not yet excluded by the model. In this paper we improve the pseudo-incompressible model and establish a new dry air dynamic core for the pseudo-incompressible model. The most significant improvement of the governing equations of the new dynamic core is that it solves an elliptic equation for perturbation pressure, which ensures the exclusion of acoustic waves in theory. The improvement in the numerical scheme of the new dynamic core is that the time-integration scheme no longer relies on the time-split algorithm. We compared the simulation results by the improved version of the pseudo-incompressible model with those by WRF model in a dry hot bubble numerical test. It is found that the pseudo-incompressible model obtains similar dynamic and thermodynamic field distributions to those from the WRF model, and the simulated perturbation pressure time series are smooth, indicating that the acoustic waves have been removed. This is a significant improvement over the pseudo-incompressible model released in 2018.

    参考文献
    相似文献
    引证文献
引用本文
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2022-03-31
  • 最后修改日期:2022-05-20
  • 录用日期:2022-07-20
  • 在线发布日期:
  • 出版日期: