Distribution and diurnal variation of warm-season short-duration heavy rainfall in relation to the MCSs in China
Distribution and diurnal variation of warm-season short-duration heavy rainfall in relation to the MCSs in China
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DOI：
10.1007/s13351-013-0605-x
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发表时间：
2013-12
影响因子：
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通讯作者：
Jiong Chen;Yongguang Zheng;Xiaoling Zhang;Peijun Zhu
中科院分区：
文献类型：
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作者：
Jiong Chen;Yongguang Zheng;Xiaoling Zhang;Peijun Zhu
短时强降水是一种强对流天气，常造成重大的财产和生命损失。利用19年（19912-2009年）876个台站的质量控制小时雨量计资料，推导出暖季（4 - 9月）中国地区SDHR的时空分布和日变化，并与卫星资料推导的中尺度对流系统（MCS）的日变化特征进行比较。结果如下。1)小时降水量大于10-40 mm的SDHR事件频率的空间分布与中国大陆强降水（日降水量≥ 50 mm）的分布非常相似。2)SDHR最常发生在中国南方，如云南南部，贵州和江西省，四川盆地和长江下游等。在中国北方也出现了一些小时降水量超过50 mm的SDHR事件，例如，新疆西部和内蒙古中东部。海南岛降水量最大，达180 mm以上。3）7月SDHR事件发生频率最高，其次是8月。对SDHR候变化的分析表明，SDHR事件是间歇性的，7月的第四候是最活跃的。随着东亚夏季风的到来，中国大陆的SDHR频率缓慢增加，但随着其撤退迅速减少。4)SDHR活动的日高峰出现在下午晚些时候（北京时间（BT）1600-1700），次高峰出现在午夜后（0100-0200 BT）和清晨（0700-0800 BT），而日最小值出现在上午晚些时候到中午（1000-1300 BT）。5)中国大陆的太阳辐射日变化与中国大陆的MCS日变化基本一致，但不同地区太阳辐射和MCS的活跃期和传播方式不同。SDHR和MCS日周期中局部极大值的数量和持续时间也因地区而异，在某些情况下具有单峰、双峰甚至多峰。这些变化可能与大尺度大气环流、地表条件和海陆分布的差异有关。
Short-duration heavy rainfall (SDHR) is a type of severe convective weather that often leads to substantial losses of property and life. We derive the spatiotemporal distribution and diurnal variation of SDHR over China during the warm season (April–September) from quality-controlled hourly raingauge data taken at 876 stations for 19 yr (19912-2009), in comparison with the diurnal features of the mesoscale convective systems (MCSs) derived from satellite data. The results are as follows. 1) Spatial distributions of the frequency of SDHR events with hourly rainfall greater than 10–40 mm are very similar to the distribution of heavy rainfall (daily rainfall ⩾ 50 mm) over mainland China. 2) SDHR occurs most frequently in South China such as southern Yunnan, Guizhou, and Jiangxi provinces, the Sichuan basin, and the lower reaches of the Yangtze River, among others. Some SDHR events with hourly rainfall ⩾ 50 mm also occur in northern China, e.g., the western Xinjiang and central-eastern Inner Mongolia. The heaviest hourly rainfall is observed over the Hainan Island with the amount reaching over 180 mm. 3) The frequency of the SDHR events is the highest in July, followed by August. Analysis of pentad variations in SDHR reveals that SDHR events are intermittent, with the fourth pentad of July the most active. The frequency of SDHR over mainland China increases slowly with the advent of the East Asian summer monsoon, but decreases rapidly with its withdrawal. 4) The diurnal peak of the SDHR activity occurs in the later afternoon (1600–1700 Beijing Time (BT)), and the secondary peak occurs after midnight (0100–0200 BT) and in the early morning (0700–0800 BT); whereas the diurnal minimum occurs around late morning till noon (1000–1300 BT). 5) The diurnal variation of SDHR exhibits generally consistent features with that of the MCSs in China, but the active periods and propagation of SDHR and MCSs differ in different regions. The number and duration of local maxima in the diurnal cycles of SDHR and MCSs also vary by region, with single, double, and even multiple peaks in some cases. These variations may be associated with the differences in large-scale atmospheric circulation, surface conditions, and land-sea distribution.