| 摘要: |
| 近年来,随着高精度中尺度数值预报模式和多尺度统一模式的发展,与之相关的一些非静力中尺度模式技术也随之提了出来,垂直坐标系的影响问题就是其中之一。本文借助于高精度美国新一代数值预报模式WRF(Weather Reseachand Forecast),模拟分析了两种不同的坐标系对模式大气中垂直速度计算的影响。试验结果表明,不同的坐标系对大气垂直速度大小计算存在着差异,特别是当分辨率提高时,不同垂直坐标系对大气垂直结构的刻画的差别更加明显。由于垂直速度与降雨过程密切相关,垂直速度的计算差异必然影响模式对降雨过程的描述。理想试验结果表明,在气压地形追随坐标中气压梯度力的计算对地表气压计算很敏感。 |
| 关键词: 数值预报模式 坐标系 垂直速度 气压梯度力 |
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| 基金项目:国家"十五"重点科技攻关项目《中国气象数值预报系统技术创新研究》(2001BA607B02);中国气象科学研究院《地形影响问题的研究》(7048/2002-9y-1)资助 |
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| IMPACT STUDY ON THE CALCULATION OF VERTICAL VELOCITY IN DIFFERENT VERTICAL COORDINATES |
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LI Xing-liang, CHEN De-hui, SHEN Xue-shun
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Chinese Academy of Meteorological Science, Beijing 100081, China
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| Abstract: |
| With the development of high-resolution and multi-scale unified numerical model, some of techniques about non-hydrostatic meso-scale numerical weather prediction are addressed. The impact of the vertical coordinate system is one of them. In this paper, based on a WRF (Weather Research and Forecast) model, the impact on the calculation of vertical velocity was studied with different vertical coordinates. The simulation results showed that the calculation of vertical velocity is sensitive to vertical coordinates. It is especially more evident when the resolution increased. Due to the close relationships between vertical velocity and precipitation, the difference of vertical velocity inevitably influences model's description of precipitation. An ideal experiment exhibits that pressure gradient force computations in the pressure terrain-following coordinate are sensitive to surface pressure. |
| Key words: numerical prediction model coordinate system vertical velocity pressure gradient force |
