Response to Extreme Precipitation and Wind at the End of the Rainy Season in North China

Sensitive to and obviously influenced by global climate change, China has seen a higher rate of warming than the global average and increasing extreme precipitation in the same period. Average intensity of landing typhoons in the past 30 years has significantly enhanced. In the end of 2018 rainy season in northern China, the area north of Yangtze River in eastern China was affected by typhoon Rumbia and its weakening and re-enhancement, and 45 cities in 8 provinces (municipalities) including Shanghai, Henan, Shandong and Liaoning experienced heavy precipitation and strong winds. Some regions even saw a rainfall above 400 mm and a 12-level wind. More than 4.87 million people in Shandong Province were affected with a direct economic loss of 22.3 billion yuan, of which agricultural losses accounted for 66%. Shouguang county was most badly stricken with flooding. Daily precipitation in 8 stations in Henan Province surpassed the historical high and accumulated precipitation in 3 stations exceeded 500 mm, leaving cities in serious water-logging. Dalian issued a red rainstorm warning and orange strong wind warning, and danger occurred at a key state test platform in the Bay of Bohai. Typhoon Rumbia eased the heat waves in Huanghuai area, Jianghuai area and North China as well as droughts in Henan, Shandong and southern part of Northeast China.

Rumbia was formed on the surface of the southeastern East China Sea, and its intensity is merely of a strong tropical storm. Main reasons for its resultant serious meteorological disasters include: First, the northern margin of East Asian summer monsoon has retreated southward, facilitating monsoon water vapor transport; second, combination of the tropical system and the westerly has caused higher precipitation efficiency, thus breaks through historical extremes in many places; third, tropical storms have weakened to subtropical cyclones and then strengthened to tropical storms, forming strong winds, heavy rains and high waves that have jointly blocked regional flood discharges. Therefore, frequent occurrence of extreme weathers and climate events and influences of human activities have brought serious challenges against social science response and systemic decision-making.