Quantitative Analysis of Meso-β-scale Convective Cells and Anvil Clouds over North China |
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作者姓名: | LIN Yinjing WANG Hongqing HAN Lei ZHENG Yongguang WANG Yu |
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作者单位: | 北京大学,,,, |
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基金项目: | The National Basic Research Program of China (973 Program),The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) |
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摘 要: | This paper proposes several quantitative characteristics to study convective
systems using observations from Doppler weather radars and geostationary
satellites. Specifically, in order to measure the convective intensity of
each system, a new index, named the ``Convective Intensity Ratio' (CIR), is
defined as the ratio between the area of strong radar echoes at the upper
level and the size of the convective cell itself. Based on these
quantitative characteristics, the evolution of convective cells, surface
rainfall intensity, rainfall area and convectively generated anvil clouds
can be studied, and the relationships between them can also be analyzed.
After testing nine meso-β-scale convective systems over North China during
2006--2007, the results were as follows: (1) the CIR was highly correlated
with surface rainfall intensity, and the correlation reached a maximum when
the CIR led rainfall intensity by 6--30 mins. The maximum CIR could be at
most ~30 mins before the maximum rainfall intensity. (2) Convective
systems with larger maximum CIRs usually had colder cloud-tops. (3) The
maximum area of anvil cloud appeared 0.5--1.5 h after rainfall intensity
began to weaken. The maximum area of anvil cloud and the time lag between
maximum rainfall intensity and the maximum area of anvil cloud both
increased with the CIR.
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关 键 词: | 对流系统 细观尺度 定量分析 细胞 中国 华北 多普勒天气雷达 降雨强度 |
收稿时间: | 9/3/2009 12:00:00 AM |
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