“23·7”华北极端强降水过程的水汽来源定量贡献分析

Quantitative contribution analyses of moisture sources for the

中文关键词:  “23·7”极端强降水，水汽源区，定量贡献，FLEXPART模式

中文摘要:

      借助拉格朗日轨迹追踪模式FLEXPART（the Flexible Particle Model）和水汽源区定量贡献分析方法，研究了“23·7”华北极端强降水过程的主要水汽源地、输送路径和源区水汽的定量贡献及随时间的变化特征。研究确定的六个主要水汽源区中西太平洋区域（E）水汽总摄取量最大（目标区域降水量的1.93倍），阿拉伯海–孟加拉湾区域（D）和中国南部区域（C）分别以0.96倍和0.76倍目标区域降水量的水汽摄取位居其后，目标区域（T，0.30倍）、目标区域外侧东北亚大陆区域（B，0.28倍）和欧亚大陆区域（A，0.01倍）摄取的总水汽量依次减少。初始时段，受越赤道气流和副高影响，D区和E区是主要水汽摄取源（两者占比总和超90%）。中间阶段，D区气块移入E区并入热带气旋“杜苏芮”环流，水汽摄取量下降，而E区因“杜苏芮”水汽摄取量显著增加。过程开始前，随“杜苏芮”登陆C区，C区水汽摄取达到峰值。最终各源区对目标区域降水的总贡献达95.34%，其中E区（43.10%）和C区（26.47%）是主要贡献区，D区（12.26%）和T区（11.85%）也有重要影响，B区（1.58%）和A区（0.08%）贡献较小。“杜苏芮”对气块运动和水汽摄取有显著影响，而热带气旋“卡努”对此次过程的直接影响相对较小。

英文摘要:

      Using the Lagrangian particle dispersion model FLEXPART (the Flexible Particle Model) and the quantitative contribution analysis method of moisture sources, the main moisture source areas, transport paths, and quantitative contributions of moisture sources along with temporal variations in the "23·7" extreme heavy rainfall in North China were studied. Six main water vapor source regions were identified, with the Western Pacific ocean (E) having the largest total water vapor uptake, equivalent to 1.93 times the accumulated precipitation amount over the target area. Following closely were the Arabian Sea-Bay of Bengal region (D) and the southern China region (C), with water vapor uptakes of 0.96 and 0.76 times the target area"s precipitation, respectively. The target area (T, 0.30 times), the northeastern Asian continental region outside the target area (B, 0.28 times) and the Eurasian continental region (A, 0.01 times) successively showed decreasing total water vapor uptake. During the initial phase, influenced by the cross-equatorial airflow and the subtropical high, regions D and E were the primary sources of water vapor uptake, accounting for more than 90% of the total. In the middle phase, air masses from region D moved into region E and merged into the circulation of tropical cyclone Doksuri, leading to a decrease in water vapor uptake in region D and a significant increase in region E. Prior to the onset of the process, as Doksuri made landfall in region C, the water vapor uptake in region C peaked. Ultimately, the total contribution of all source regions to the target area"s precipitation reached 95.34%, with region E (43.10%) and C (26.47%) being the main contributors, while regions D (12.26%) and T (11.85%) also had significant impacts and regions B (1.58%) and A (0.08%) had minor contribution. Tropical cyclone Doksuri had a notable effect on the movement of air masses and water vapor uptake, while the direct impact of tropical cyclone Khanun on this process was relatively small.