East Asia: Water surpluses will persist in Henan, deficits in Hunan

25 July 2018

THE BIG PICTURE
The 12-month forecast for East Asia indicates exceptional water deficits in a large block of western Inner Mongolia and deficits nearly as intense in much of Taiwan. Moderate to exceptional deficits are forecast for Mongolia and moderate to extreme deficits in Southeast China.

Severe surpluses are expected along the Hudi River in Anhui leading west to surpluses in the Han River Basin (Hanjiang), an eastern tributary of the Yangtze, which may be extreme in Henan. Farther west, surpluses reaching exceptional intensity are forecast throughout much of Qinghai and central Sichuan. Along the Yellow River (Huang), severe surpluses are forecast on the middle and lower reaches. In southern China, severe surpluses are forecast in the Nanpan River Basin in eastern Yunnan and the Jinsha (Yangtze) in northwestern Yunnan. Surpluses are expected to reach exceptional intensity in western Tibet and along the western Yarlung River (Brahmaputra) north of Nepal.

Surpluses are forecast for North Korea, northern South Korea, and western Hokkaido, Japan.

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

The near-term forecast through September indicates that the extent of exceptional deficits in Mongolia and Inner Mongolia through southern Xinjiang will diminish considerably, as well as in Southeast China and Taiwan. A large pocket of exceptional deficits will persist in western Inner Mongolia mixed with conditions of both deficit and surplus as transitions occur. In the Southeast, moderate to severe deficits will persist in Guizhou, Hunan, Guangxi, Jiangxi, Guangdong, Fujian, Zhejiang, Hong Kong, and Taiwan, with some pockets of exceptional deficit lingering in Hunan.

Surpluses on the Lower and Middle Reaches of the Yellow River will downgrade, and while the extent of exceptional surpluses will shrink in Qinghai, intense surpluses will persist. Surpluses in the Han River Basin will also diminish and downgrade, but intense surpluses remain in the forecast for western Henan, southern Shaanxi, and southern Gansu. Downgrades are also forecast for the Nanpan River in eastern Yunnan and the Jinsha River (Yangtze) in northwestern Yunnan, though surpluses will be severe in the northwest. Exceptional surpluses are forecast in western Tibet and along the western Yarlung (Brahmaputra) River, with deficits in eastern Tibet. Surpluses in Hainan will moderate.

Primarily moderate surpluses are forecast for North Korea and northern South Korea. In Japan, surpluses are forecast for Hokkaido and moderate deficits in Honshu.

The forecast for October through December indicates that deficits will persist in Southeast China downgrading slightly; moderate deficits will emerge in Hainan and intense deficits will re-emerge in southern Taiwan. Deficits in southern Mongolia will become severe, and severe to extreme deficits will expand from western Inner Mongolia through Xinjiang, though some areas will exhibit both deficit and surplus. Surpluses will persist in aforementioned areas but will diminish. Conditions in Hokkaido are expected to normalize.

The forecast for the final months – January through March – indicates that conditions in Southeast China will transition from deficit to moderate surplus, but deficits elsewhere, as indicated in the preceding three-month forecast, will persist in China and Mongolia.

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

IMPACTS
With the death toll still rising, at least 122 people were killed in floods and landslides after days of heavy rainfall in southwestern Japan in early July. In Sukumo City, over 10 inches of rain fell in two hours, according to a Japanese broadcaster. Thousands of houses were damaged, and two million people were advised or ordered to evacuate. Photos show some families stranded on their rooftops, the houses below entirely submerged.

Southwest China experienced heavy rain in June, affecting 115,000 people in Sichuan Province. Rains triggered a mountain collapse, killing four people and injuring one person. Thousands of acres of crops were damaged, resulting in nearly $24 million in economic losses. Flooding engulfed a village in Guizhou Province, stranding people outside of their submerged houses. In Fujian Province, roads were flooded up to 30 centimeters (11.8 inches).

Heavy downpours in eastern China’s Anhui Province early this month affected 160,000 people, and damaged thousands of acres of crops and over 300 houses, amounting to around $12 million in losses.

A severe storm sent marine life flying onto city streets of Qingdao, China in mid-June. A number of waterspouts in the Yellow Sea are the alleged culprits of the so-called “seafood rain.” Hurricane-force winds associated with the storm caused destruction throughout the city.

China’s wheat output could drop by 20 percent this year due to unfavorable weather ranging from drought in the Shandong and Hebei provinces, to damaging rains in Henan and Anhui provinces.

Forest fires broke out in north China’s Inner Mongolia Autonomous Region early last month, sending thousands of police and fire fighters to the battle. The fire was extinguished within five days of their deployment after burning 5,100 hectares (12,600 acres) of forest. Drought in the region is additionally affecting millions of acres of grassland and millions of livestock, amounting to over 600 million yuan (USD $91 million) in economic losses. A boom in the population of rodents, which are particularly adaptable to drought, is compounding the threat to the region’s famous grasslands; the rats eat grass roots and disturb the habitat with underground digging.

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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