| 摘要: |
| 【目的】探究木兰溪流域性极端短时暴雨时空和雨程分布的特征及原因。【方法】利用木兰溪流域2010—2020年逐时降水资料分析极端过程的时空特征、天气背景，应用模糊识别法分析降雨时程分布特征。【结果】（1）影响天气系统为锋面或台风，台风型过程的持续时间、影响范围和累计过程雨量明显强于锋面过程。（2）最强降水时段锋面型过程有日变化，台风型过程无日变化，且锋面型高峰期较福建沿海60 min极端强降水出现时间迟3 h左右。（3）流域性极端短时暴雨过程主要在5—9月，与莆田市暴雨日数季节分布类似，但两者7月出现频次在全年中占比不同，前者占比为全年最高，后者仅排全年第3。（4）极端过程的雨程分布呈单峰后部型，降雨集中度高，强降水主要出现在后半程。【结论】日落后气温较午后低，有利于锋面快速过境，激发不稳定能量彻底释放，使锋面型过程降雨集中度高。而台风型过程降雨集中度高的原因除了极端过程算法自身限制外，还与台风中心与强降水区一致性移动、台风内部强对流的中尺度特征有关。钟形和盆地地形在热力及动力条件上的优势使榜头溪中上游、大济溪上游和延寿溪上游成为流域性极端短时暴雨易发点，需关注极端短时暴雨可能引发的木兰溪流域性河水猛涨。 |
| 关键词: 流域性;极端短时暴雨;雨程;集中度 |
| DOI： |
| 投稿时间：2024-01-09修订日期：2024-04-15 |
| 基金项目:福建省气象局开放式科研基金项目(2021KFM01):引发木兰溪流域山洪暴雨预报技术研究。 |
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| Characteristics of Regional Extreme Short-time Rainstorm in Mulan River Basin |
| CHEN Shilin,ZHANG Xiangliang,CHEN Yuhang,Yang Denan |
| (Chengxiang Meteorological Bureau of Fujian Province;Xianyou Meteorological Bureau of Fujian Province;Putian Meteorological Bureau of Fujian Province;Zhangzhou Meteorological Bureau of Fujian Province) |
| Abstract: |
| To explore the characteristics and causes of temporal, spatial and rain duration distribution of regional extreme short time rainstorm in Mulan River. The temporal and spatial characteristics and weather background of extreme processes were analyzed by using the hourly precipitation data of Mulan River Basin from 2010 to 2020, and the temporal distribution characteristics of rainfall were analyzed by fuzzy identification algorithm. (1) The affected weather system is front or typhoon, and the duration, influence range and cumulative rainfall of the typhoon-type process are obviously stronger than that of the front process. (2) During the strongest precipitation period, the front type process has diurnal variation, while the typhoon type process has no diurnal variation, and the peak of the front type is about 3 hours later than the 60-minute extreme heavy precipitation along the coast of Fujian. (3) The process of regional extreme short term rainstorm was mainly from May to September, which was similar to the seasonal distribution of the number of rainstorm days in Putian City, but the frequency of occurrence in July accounted for a different proportion in the whole year, with the former accounting for the highest proportion in the whole year and the latter ranking only the third in the whole year. (4) The rain course distribution of the extreme process was unimodal posterior type, with high rainfall concentration, and heavy precipitation mainly appeared in the second half of the process. The temperature after sunset is lower than that in the afternoon, which is conducive to the rapid transit of the front, stimulates the complete release of unstable energy, and makes the rainfall concentration of the front type process high. The reason for the high rainfall concentration in typhoon type processes is not only limited by the extreme process algorithm itself, but also related to the consistent movement of the typhoon center and the strong rainfall area，and the mesoscale characteristics of the strong convection inside the typhoon. The advantages of bell shape and basin topography in thermal and dynamic conditions make the middle and upper reaches of Bangtou Creek, Daji Creek and Yanshou Creek prone to extreme short term rainstorm. It"s necessary to pay attention to the violent rise of Mulan River which may be caused by extreme short term rainstorm. |
| Key words: river region; extreme short time rainstorm; the rain course; concentration degree |
