East Asia: Water deficits to emerge in South Korea, Japan, & persist in Mongolia

26 April 2017

The Big Picture
As seen in the 12-month forecast map for East Asia ending December 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 deficits are forecast in eastern Tibet and surpluses in a wide north/south swath of central Tibet. Primarily deficits are forecast in the Tarim Basin of southern Xinjiang.

Impacts
Though recent rainfall in Taiwan has helped alleviate drought in northern and central regions - bringing Shimen Reservoir in Taoyuan up to 55 percent of capacity, a 12-day supply - it has done little to relieve the situation in the south. Wushantou and Tsengwen reservoirs remain at less than 20 percent of capacity - a 2-day supply - and Nanhua Reservoir has 1.2 days. The Water Resources Agency (WRA) will consider whether to lift first-stage water rationing measures in the north. The December through February drought, whose effects are lingering, is Taiwan's second worst in 70 years, says the WRA.

Last year's drought in Shandong Province reduced Fuji apple yield by 10 to 15 percent over previous years, reported Yantai Quanyuan Food Co.Ltd., and led to disease and pest infestation that negatively affected fruit size and quality and contributed to an increase in export prices.

Heavy rain caused flooding in Fujian Province in southeastern China. In Fuzhou motorists abandoned their cars as street water reached 80 cm (31.5 inches). Nearly 1,800 homes were without power in Zhangzhou City.

China recorded its highest rainfall levels ever in 2016, up 13 percent from 2015 according to the China Meteorological Administration. Eastern and southeastern parts of the country were especially hard-hit. It's worth noting that Guangzhou, a sprawling metropolis of over 13 million people in the Pearl River Delta of southeast China's Guangdong Province, tops the World Bank's global list of coastal cities at highest risk of flood damage.

Authorities in Liaoning Province in northeastern China admitted that two municipal governments in the region deliberately under-reported the death toll from flooding that occurred in 2012. Though only 5 casualties were reported Chinese National Radio put the figure at 38.

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

The most noticeable change in the April through June map is the white area in southeast China, indicating a return to normal conditions from surpluses observed in prior months. To the north, the Yellow River is also apparent – as seen in the purple path – indicating that, as deficits emerge in the region, the river will transition out of moderate surplus conditions observed in prior months. Moderate to extreme deficits are forecast to emerge in South Korea and throughout Japan. Moderate deficits are expected to emerge in Northeast China, the Shandong Peninsula, Henan, and Shaanxi.

Severe to exceptional deficits are forecast to persist in southern Mongolia, and in western Inner Mongolia; the Tarim Basin and eastern Dzungaria regions of southern Xinjiang; and southern Liaoning in China. Surpluses are forecast for northern Sichuan and much of Qinghai. Primarily surpluses are expected in central Tibet from central Nepal northward.

The forecast for July through September indicates the persistence of exceptional deficits in western Inner Mongolia and moderate to severe deficits in Mongolia. Moderate to severe deficits are forecast to emerge in the Sichuan Basin, trailing eastward to the Jiangsu coast. Normal conditions are forecast for the Korean Peninsula, and deficits in Japan are expected to diminish. A complex patchwork of deficit and surplus is forecast to persist in western China, though the extent and severity will diminish somewhat.

The forecast for the final months – October through December – shows the continued presence of moderate deficits in the Sichuan Basin and more intense deficits in Mongolia.

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