In the summer of 1960, the Pacific subtropical high was stronger after moving northward, and its position was more eastward than normal years. It combined with the Okhotsk high and formed a stronger high pressure dam, which stayed in Japan and the eastern Pacific. The warm and wet air in the south was constantly moving northward, and the number of times in the Songhua River basin was increased directly or indirectly by the typhoon, while the activities of various low-pressure systems were frequent. In this year, Pacific has more than 20 times typhoons. There were seven typhoons in the north, which had four direct or indirect effects on the Songhua River basin. The typhoon affected Lake Baikal low pressure 10 times, Mongolia law pressure 7 times, Hetao low pressure 3 times, cold vertex 3 times and warm and wet air in the Pacific Ocean 4 times in the Songhua River basin. Under the influence of these systems, the Songhua River basin mostly had rainstorms. The two rainstorms on August 5th to 7th and 22nd to 23rd were mainly caused by the influence of typhoons.
There are flat air circulation patterns in the sky over Asia, and the position of the western Pacific subtropical high of which center is located in Japan trended to the north. The center of the typhoon disappeared at 14:00, 6th, but the rain belt caused by the typhoon went to the north along the subtropical high so the airflow from the southwest went to the northeast and influenced the east area of Songhua River basin, caused the rainstorm in the basin of Lalin River, Mayi River, Mudan River. Besides, the cold air which used in Lake Balkhash went to the east and entered in the south Xinjiang through Mount Tianshan. This movement made the low pressure front in the Hetao Plains, the west of Yinchuan, went to the northeast quickly. The center of this low pressure entered into the basins of Songhua River from the east at 20:00, 7th and then caused the rainstorm in the areas of Hulan River and Tangwang River.
The rainstorm in the basins of the east of the Songhua River was caused by the 14th typhoon directly during 21st and 23rd in August, 1960. There was a powerful high-pressure ridge between two low vortexes, one was located in the west of the Siberia, and the other was situated near Chita in Asia on 21st, August. The position of the center of the western Pacific subtropical high trended the north but still on the ocean floor of southeast Japan. The typhoon was near Okinawa. The subtropical high went to the north because of the typhoon approached the south of it. The typhoon went to the north and entered into the area of Songhua River quickly when it was situated in the front of the low vortex which was in Chita and the west of the subtropical high, and it moved 12 wefts during 24 hours on 23rd and 24th. And the subtropical high turned into an extra tropical cyclone because of the invasion of the cold air from the southwest of the typhoon, so in the upper air map, there was rainstorm in the warm and flat place of the east wind, and that is to say, the rainstorm happened in the west of the typhoon's central path-the area of the second Songhua River, Mudan River and the branches of Tumen River.
The information is provided by Disaster Risk Reduction Knowledge Service.
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