| 中国东部雨季降水事件的静默时间特征及内在动力学机制初探 |
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| 引用本文： | 钱忠华,周前进,刘莉,封国林.中国东部雨季降水事件的静默时间特征及内在动力学机制初探[J].气象学报,2020,78(6):914-927. |
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| 作者姓名： | 钱忠华 周前进 刘莉 封国林 |
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| 作者单位： | 1.扬州大学物理科学与技术学院，扬州，225009 |
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| 基金项目： | 国家重点研发计划项目（2017YFC1502306、2017YFC1502305）、国家自然科学基金项目（41675050、42075057、41875100） |
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| 摘 要： | 为了挖掘降水的内在非线性动力学机制，基于1960—2017年4—9月的中国日降水数据，利用百分位阈值法确定不同强度的降水事件，定义相邻同强度降水事件之间的间隔时间为“静默时间”，描述同阈值降水事件再次发生的历时长短。“平均静默时间”可以表征不同强度降水事件的群发性特征，即某一时段内，平均静默时间越短（长），同类型降水事件再次发生的历时越短（长），其群发性程度越强（弱）。分析不同强度降水事件的平均静默时间在中国东部地区的空间分布和时间演变特征表明: 1960—2017年，一般强度降水事件在长江中游地区较其余地区群发性强，而东北南部地区则较弱； 极端降水事件在中国东部北方地区群发性较强，而在南方地区则偏弱。就气候态演化过程而言，一般强度降水事件的群发性在长江以南地区有所增强，在东北南部地区则呈减弱趋势；极端降水事件的群发性特征在中国东部北方地区不断减弱，但在南方地区持续增强。各站点降水事件静默时间的概率密度函数均呈幂律分布，且时、空上呈无标度特征，表明日降水系统为现实世界中的自组织临界系统，为时间序列分析角度理解降水事件内在非线性动力学机制提供了新的视角。
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| 关 键 词： | 降水事件 静默时间 时空演化 幂律分布 自组织临界 |
| 收稿时间： | 2019/9/6 0:00:00 |
| 修稿时间： | 2020/8/8 0:00:00 |
A preliminary study on the characteristics of quiet time and intrinsic dynamic mechanism of precipitation events in the rainy season in eastern China |
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| QIAN Zhonghu,ZHOU Qianjin,LIU Li,FENG Guolin.A preliminary study on the characteristics of quiet time and intrinsic dynamic mechanism of precipitation events in the rainy season in eastern China[J].Acta Meteorologica Sinica,2020,78(6):914-927. |
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| Authors: | QIAN Zhonghu ZHOU Qianjin LIU Li FENG Guolin |
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| Institution: | 1.Physical Science and Technology College，Yangzhou University，Yangzhou 225009，China2.Nanjing University of Information Science & Technology，Nanjing 210044，China3.Laboratory for Climate Studies，National Climate Center，China Meteorological Administration，Beijing 100081，China |
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| Abstract: | To explore the inherent nonlinear dynamic mechanism of precipitation, based on daily precipitation data from April to September for the period 1960—2017 in eastern China, the intensity of precipitation is determined by the percentile threshold method, and the time interval between adjacent same-intensity precipitation events is defined as "quiet time" to describe the duration of the recurrence of the same intensity precipitation. The "average quiet time" is then used to characterize the massive feature of precipitation events with different intensities. Specifically, in a certain period, the intervals are shorter (longer) for the recurrence of the same type of precipitation event while the stronger (weaker) the degree of clustering of precipitation events become, if the average quiet time is shorter (longer). Next, spatial and temporal evolution characteristics of the average quiet time of different intensity precipitation events in eastern China are provided. Further in-depth analysis is conducted with the focus on the inherent nonlinear dynamic characteristics of the precipitation. The results show that the massive feature of general intensity precipitation events is stronger in the middle reaches of the Yangtze River than in other areas, and it is weaker in the southeastern part. The massive feature of extreme precipitation events is stronger in the northern part of China but the opposite is true in the south during 1960—2017. As far as the climatic state evolution process is concerned, the massive feature of the general intensity precipitation group shows a certain enhancement to the south of the Yangtze River, and a weakening trend appears in the southeastern part of eastern China. The cluster characteristic of the extreme precipitation events is weakening in the northeastern part of China but the opposite is true in the south. The probability density function of the quiet time of precipitation events at each station shows a power-law distribution pattern and a scale-free feature in space and time, indicating that daily precipitation is a self-organized critical system in the real world, which provides a new perspective for understanding the internal nonlinear dynamic mechanism of precipitation. |
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| Keywords: | Precipitation events Quiet time Spatiotemporal evolution Power law distribution Self-organized critical |
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