East Asia: Water deficits forecast in Mongolia, Inner Mongolia; surpluses Jiangsu

29 March 2017

The Big Picture
As seen in the 12-month forecast map for East Asia ending November 2017 (below), exceptional water deficits are forecast for western Inner Mongolia, China. Deficits are also forecast for central Mongolia, Ningxia, Gansu, Shaanxi, Sichuan, and Taiwan.

In western China both deficits and surpluses are forecast in Tibet, and primarily deficits are forecast in the Tarim Basin of southern Xinjiang.

Impacts
The Qinghai-Tibet plateau in China - source of the Mekong, Yellow, and Yangtze Rivers which provide water for millions of people in China and Southeast Asia - is drying up, say researchers. Glaciers at the headwaters are receding, creating less melt water flowing into the rivers. Seasonal dry-outs as well as desertification have dried up wetlands and pastures forcing over-grazing or leading herders in the region to search for new pasture. The Chinese government has begun preservation efforts by designating the area as a national park.

China is studying the feasibility of a 1,000km (620 mile) pipeline to siphon water from Russia's Lake Baikal to Gansu province in northern China. The pipeline would extend from the southern tip of the lake through Mongolia to Gansu's capital, Lanzhou.

Recent rainfall has not been sufficient to alleviate Taiwan's water shortage. "Phase One" water rationing has been instituted in Taoyuan, Hsinchu and New Taipei's Linkou, Banqiao and Xinzhuang districts where water pressure will be reduced during overnight hours from 11pm to 6am.

Forecast Breakdown
The 3-month maps show the evolving conditions in more detail.

From March through May severe to extreme deficits are forecast to persist in: southern Mongolia; western Inner Mongolia, the Tarim Basin and eastern Dzungaria regions of southern Xinjiang, and southern Liaoning in China; and Hokkaido, Japan. Moderate to severe deficits are forecast to emerge in southeast China from Zhejiang through eastern Yunnan, and in Taiwan, South Korea, and eastern Honshu, Japan. Moderate deficits will persist in southern Shaanxi and eastern Sichuan, and may become severe along the Han River. Surplus conditions are expected to persist in Jiangsu. Both deficits and surpluses are forecast in Hainan as the province transitions from surplus to deficit.

Much of eastern China is forecast to transition away from significant water anomalies from June through August. However, severe to exceptional deficits remain in the forecast for western Inner Mongolia. A pocket of exceptional deficit is also forecast for eastern Tibet. Moderate deficits are forecast during this period for Mongolia, Hainan, and Japan. Deficits in southern Yunnan may be more intense. Primarily surpluses are expected in northern Tibet, and in southern Tibet north of Nepal along the Maquan River (Dangque Kaba) where surpluses may reach exceptional intensity.

The forecast for September through November is similar to June through August with an increase in deficits in northwestern China.

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