The Jianghuai cyclone is a cyclone system with obvious cold and warm front structure generated in the middle and lower reaches of the Yangtze River and the Huaihe River basin (26 ° N~35 ° N, 113 ° E~120 ° E).
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The Jianghuai cyclone mainly occurs in the following three regions:
The middle and lower reaches of the Yangtze River: from Yichang in the west to the Yangtze River estuary in the east, the two latitudes along the two banks of the Yangtze River are the regions with the largest number of cyclones in the Yangtze River and Huaihe River, accounting for 62% of the total number of cyclones in the Yangtze River and Huaihe River.There are two moving paths, one is to the northeast and east, passing through the northern part of the East China Sea to the southern part of Japan;The other is to go north northeast through the Yellow Sea to the Sea of Japan.Most cyclones of the latter path can be developed.
Huaihe River Basin: the area within 1-2 latitudes along the Huaihe River, accounting for 28% of the total number of cyclones in the Yangtze Huaihe River.Most of them enter the sea from Haizhou to the Sea of Japan via the Yellow Sea.
Hunan Jiangxi region: Hunan and Jiangxi provinces, which only account for 10% of the total number of occurrences, mostly enter the sea from the Yangtze River estuary.
Jianghuai cyclones can occur all year round, but most of them occur in spring and summer, especially in June.
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Jianghuai cyclones can occur all year round, but most of them occur in spring and early summer.The formation process can be roughly divided into two categories.
(1) Wave on stationary front (similar to the formation process of typical cyclones).When there is an approximately east-west quasi-static stop front in the Yangtze Huaihe River basin, if there is a short wave trough moving from the west, there is a positive vorticity advection at the lower front of the trough, which forms a cyclonic circulation. The southerly flow makes the front move northward, and the northerly flow makes the front move southward, so the stationary front becomes a cold and warm front.If the fluctuation center continues to depressurize, a Jianghuai cyclone will be formed
(2) The front of the inverted slot rotates.At the beginning, after the surface metamorphic high moved eastward into the sea, the warm air was transported northward by the southwest air flow on the upper south branch front area, and the ground depressurized to form an inverted trough and extended eastward.At this time, there is a small trough on the north branch front zone moving from the northwest, and there is a cold front and a cold high behind the front on the ground.Then, due to the continuous enhancement of the upper warm advection, the surface trough further developed and a warm front was formed in the Yangtze Huaihe region of the trough, and formed a warm front.At this time, the northwest trough continued to move eastward, and the north and south frontal zones gradually approached in the Yangtze Huaihe River basin.The cold front and its rear high also moved southeast and approached the inverted trough.Finally, the north and south frontal zones in the upper air overlap, and the small trough develops. The cold front on the ground enters the inverted trough and joins the warm front, forming the Jianghuai cyclone below the positive vorticity advection in front of the high trough.
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The movement of the Jianghuai cyclone is mainly guided by the airflow in front of the high trough, and the path is consistent with the front zone.
After the formation of the Yangtze Huaihe cyclone, precipitation will occur in the Yangtze River, Huaihe River and the lower reaches of the Yellow River. The precipitation area mainly occurs between the 700hPa trough line or shear line and the surface front.The Jianghuai cyclone is one of the main weather systems that cause strong wind, rainstorm and thunderstorm in the Jianghuai region.The rapidly developing Jianghuai cyclone is accompanied by strong gales. There are easterly gales in front of the warm front, southerly gales in the warm zone, and northerly gales behind the cold front. Rainstorm areas generally occur near the center of the cyclone or in the warm zone.
