摘要
Based on the MICPAS data and 0. 75°× 0. 75° reanalysis data of the European Center,the characteristics of large-scale circulation in the rainstorm process in Yan'an in late July in 2013 were analyzed. The results showed that the activity of the subtropical high had a significant impact on the occurrence of this rainstorm process. During the rainstorm in Yan'an,the subtropical high extended westward obviously,and the southerly airflow on the periphery of the subtropical high intersected with cold air in northern Shaanxi. The good coupling of high-and low-level jet stream provided dynamic conditions for the occurrence of downpour. During the rainstorm,the low-level jet stream at 850 h Pa was radial,and the high-level jet stream at 200 h Pa in this process was in a quasi-horizontal direction. In the rainstorm process,there was an obvious large-value band of water vapor transport,while the water vapor flux arrived at a high latitude,and the intensity was great.
Based on the MICPAS data and 0. 75° × 0. 75° reanalysis data of the European Center,the characteristics of large-scale circulation in the rainstorm process in Yan'an in late July in 2013 were analyzed. The results showed that the activity of the subtropical high had a significant impact on the occurrence of this rainstorm process. During the rainstorm in Yan'an,the subtropical high extended westward obviously,and the southerly airflow on the periphery of the subtropical high intersected with cold air in northern Shaanxi. The good coupling of high-and low-level jet stream provided dynamic conditions for the occurrence of downpour. During the rainstorm,the low-level jet stream at 850 h Pa was radial,and the high-level jet stream at 200 h Pa in this process was in a quasi-horizontal direction. In the rainstorm process,there was an obvious large-value band of water vapor transport,while the water vapor flux arrived at a high latitude,and the intensity was great.
