East Asia: Water surpluses in Shanghai, deficits in Inner Mongolia

27 February 2017

The Big Picture
As seen in the 12-month forecast map for East Asia ending October 2017 (below), water surpluses are forecast for Shanghai, Jiangsu, and Anhui. Exceptional deficits are forecast for western Inner Mongolia, China. Deficits are also forecast for southern Mongolia, Ningxia, Gansu, Shaanxi, Sichuan, and northern Taiwan.

A patchwork of water anomalies is forecast for western China.

Impacts
The water level at Taiwan's Shihmen Dam has dropped below 60 percent of capacity, according to the Water Resources Agency, prompting consideration of water restrictions on some Northern Taiwan areas. Shihmen, which supplies water to Taiwan and some areas in Greater Taipei, has been on drought alert since November 2016. Two other reservoirs, Nanhua Dam and Tsengwen Dam, are also at less than 60 percent of their capacity, and the Central Weather Bureau has predicted that dry weather could persist through spring.

The United States provided $1 million in humanitarian aid to North Korea in late January. The award, administered through UNICEF, comes as North Korea continues to recover from flooding in mid-2016 - the aftermath of Typhoon Lionrock - which resulted in hundreds of deaths and thousands of homes destroyed.

In an effort to control its worsening smog problem, Mongolia's capital of Ulaanbaatar has increased restrictions on migrants. Over 80 percent of the capital's smog is generated by the sprawling "ger" districts whose inhabitants - former herders who migrated to the city after harsh winters destroyed their livestock - have no access to the state heating grid and burn anything they can to keep warm. Ulaanbaatar's level of harmful breathable particles rose to 1,000 micrograms compared to the World Health Organization recommendation of 20-25 micrograms and Beijing's 70 micrograms. For two years in a row a "dzud" - dry summer followed by severe winter resulting in livestock death by starvation - has forced herders to migrate to the city, putting a strain on city resources.

Forecast Breakdown
The 3-month maps (below) show the evolving conditions in more detail. Looking at all four maps it’s clear that the first six months are characterized by exceptional anomalies – both surpluses and deficits – indicated by deeper shades of blue and red, and that the latter six months show a decrease in the intensity of anomalies though they will remain widespread.

From February through April surpluses ranging from moderate to exceptional are forecast from Shanghai on the coast through Anhui, Hubei, and northern Hunan along the Lower and Middle reaches of the Yangtze Basin. Extreme to exceptional deficits are forecast for much of southern Mongolia; across the border into western Inner Mongolia, China; and western Qinchai (Qinghai), along with pockets of both deficit and surplus. Deficits of equal severity are also forecast for northern Taiwan and eastern Yunnan. Moderate with pockets of extreme deficits are expected to persist in Ningxia, southern Shaanxi, Gansu, and eastern Sichuan in the center of the country; and on the Liaodong Peninsula in Northeast China. Primarily moderate deficits will emerge in eastern Guangxi and throughout Guangdong in Southeast China. Both deficits and surpluses reaching exceptional intensity will continue to emerge in China’s western half.

Though the presence of anomalies will remain widespread May through July, the forecast indicates diminished severity of both deficits and surpluses overall. Particularly, aforementioned surpluses from Shanghai inland will recede considerably along with deficits in Southeast China, Taiwan, Inner Mongolia and Mongolia. However, moderate to exceptional deficits will continue to emerge in a large block of western Inner Mongolia. Primarily surpluses are expected in the Tibetan Plateau during this period. Relatively normal water conditions are forecast for Taiwan, the Korean Peninsula, and Japan.

The forecast for August through October is similar to May through July.

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