Analysis of the August 2019 Atmospheric Circulation and Weather
The main characteristics of the general atmospheric circulation in August 2019 are as follows. The polar vortex of Northern Hemisphere presented a single pattern. In the mid-high latitudes of Asia, the circulation presented a two-trough and one-ridge pattern. The Northwest Pacific subtropical high lay northward, and the subtropical high on land was stronger than the average. Meanwhile, the monthly mean precipitation amount was 110.5 mm, which is more than its normal value (105.3 mm) with 5.0% increase. The monthly mean temperature was 21.6℃, 0.8℃ higher than its climatological mean (20.8℃). Five regional torrential rainfall events happened in August, and three of them were caused by tropical cyclone. In August, six tropical cyclones were active over the Northwest Pacific and the South China Sea, and Typhoon Wipha (1907) and Lekima (1909) and Bailu (1911) made landfall over China. Northeast China and Sichuan suffered from heavy rains and floods. Drought appeared over middle and lower reaches of the Yangtze River. Persistent high-temperature occurred in the south of China. Many provinces suffered from hail attacks, and some areas had serious disasters.