East Asia: Water surpluses will persist south of the Yangtze

28 March 2019

THE BIG PICTURE
The 12-month forecast for East Asia through November 2019 indicates widespread surpluses in southeastern China and in much of the Tibetan Plateau, intense deficits in Inner Mongolia and Mongolia, and deficits of varying intensity elsewhere in China, the Korean Peninsula, and most of Japan.

In southeastern China, surpluses will be exceptional in Hunan and northeastern Guangxi, especially in the Xiang River region, a tributary of the Yangtze, and the Duliu River (Liu) in the Pearl River system.

Deficits reaching exceptional intensity are forecast for western Inner Mongolia and southeastern Mongolia, along with conditions of both deficit and surplus (purple) as transitions occur.

Severe deficits are forecast for western Jilin in Northeast China and neighboring regions of Inner Mongolia, with moderate deficits trailing southwest from there through eastern Sichuan, punctuated by severe deficits in the center of this path in Shanxi.

Some primarily moderate deficits are expected on the Korean Peninsula. In Japan, moderate to extreme deficits are forecast for Honshu and Hokkaido, and moderate surpluses for Kyushu.

FORECAST BREAKDOWN
The 3-month time series maps below show the evolving conditions in more detail.

The forecast through May indicates the emergence of a vast stretch of extreme to exceptional water deficits in southern and eastern Mongolia and into Inner Mongolia, China, interspersed with conditions of both deficit and surplus as transitions occur. Deficits will increase and intensify in western Jilin and western Liaoning to the Bohai Sea, becoming exceptional. Moderate to severe deficits will form a broad path from Beijing through Shanxi and Shaanxi into eastern Sichuan. Conditions of both deficit and surplus (purple) are forecast on the Ordos Loop of the Yellow River as transitions occur.

In the southeast, widespread surpluses will persist in the Yangtze Basin’s Lower Reaches and in the southern portion of the Middle Reaches, reaching into Guangxi, but surpluses of exceptional intensity will nearly disappear, lingering around Shanghai and in the Duliu River (Liu) region of Guangxi. Moderate to severe deficits are forecast on the Han River, a northern tributary of the Yangtze, and intense surpluses are expected to persist in the Upper Yangtze Reaches and much of the Tibetan Plateau. Surpluses will be exceptional along the Yarlung River (Brahmaputra). Moderate deficits will emerge in Hainan and conditions in Taiwan will transition from intense deficit to near-normal.

On the Korean Peninsula, deficits will emerge, transitioning from normal or surplus conditions. Deficits will be severe to extreme and will be widespread in North Korea. In Japan, intense deficits will increase, with exceptional anomalies in Honshu and Hokkaido. Moderate surpluses will persist in eastern Kyushu.

From June through August, surpluses in southeastern China will diminish considerably leaving some moderate surpluses along the Lower and Middle Yangtze and nearly normal conditions in Anhui, Zheijiang, and eastern Jiangxi. Surpluses will increase in Guangxi and Guangdong, of generally moderate intensity but severe along many rivers. Moderate surpluses will emerge in southern Taiwan. Surpluses will downgrade in the Tibetan Plateau. Deficits will downgrade in Mongolia but will be severe, and intense deficits will persist in western Inner Mongolia along with conditions of both deficit and surplus. Deficits in Northeast China and from Beijing through Sichuan will downgrade to moderate or mild. Mild deficits are forecast on the Korean Peninsula. In Japan, deficits will moderate on Honshu, but severe deficits are forecast for Hokkaido.

The forecast for the final three months – September through November – indicates extreme deficits in western Inner Mongolia and Xinjiang along with conditions of both deficit and surplus, and moderate deficits in Mongolia. Moderate deficits are also forecast in China radiating from the Sichuan Basin. Moderate surpluses will persist in the Pearl River Basin (Zhujiang) in the south.

(It should be noted that forecast skill declines with longer lead times.)

IMPACTS
The government of North Korea issued a statement claiming that drought, floods, and United Nations sanctions have caused a food shortfall which has forced food rations to be cut by half. The memo was released a week prior to a summit between Kim Jong Un and United States President Donald Trump. The United Nations confirmed a North Korean report that the country’s food production last year was 503,000 metric tons lower than that of 2017, comprising its lowest food production level in over a decade.

Lack of snow in Mongolia and current dry conditions have prompted the country’s National Emergency Management Agency to bolster efforts to prevent forest and steppe fires. As part of the effort, backcountry travel, hiking and other activities in forested areas will be banned until June.

Drought-related fodder shortages have decimated Mongolia’s Saiga antelope population, an endangered species. According to the Worldwide Fund for Nature (WWF), the herd suffered a 40 percent reduction in numbers from 2017 to 2018, with merely 3,800 Mongolian Saiga antelopes remaining.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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