East Asia: Exceptional water deficits forecast for western Inner Mongolia

25 May 2017

The Big Picture
As seen in the 12-month forecast map for East Asia ending January 2018 (below), exceptional water deficits are forecast for western Inner Mongolia, China. Deficits are also forecast for central Mongolia, northwestern Qinghai, Guizhou, Sichuan, southern Liaoning, Taiwan, and Hokkaido, Japan.

In western China deficits are forecast in southeastern Tibet and surpluses in a wide north/south swath of central Tibet. Primarily deficits are forecast in the Tarim Basin of southern Xinjiang.

Impacts
In response to drought in South Korea the Ministry of Agriculture and Fisheries will provide KRS$4 billion (South Korean Wan; USD$3,564,678) assistance to drought-struck agricultural regions including southern Kyonggi Province (Gyeonggi do) and Chungnam Province (Chungcheongnam do). The Ministry reports that national average precipitation this year is 155mm (6 inches), 60 percent of the past average (259 mm; 10 inches), and that agricultural reservoirs are at 72 percent compared with 81 percent last year. Rainfall in Incheon City has also been sparse this year: 96mm (3.8 inches) through April 2017 compared to 262mm (10.3 inches) the prior year. Dry conditions threaten to delay rice planting.

The drought has fueled a series of forest fires in South Korea, forcing evacuation of 2,500 residents of Gangneung city on May 6. Nearly 2,700 firefighters, soldiers, police officers, and government officials were called in. Fires were also reported on the same day in Samcheok, requiring 14 helicopters and 820 responders; and in Sangju, where 215 residents were evacuated.

Recent rainfall has helped relieve drought conditions in north China affecting 100,000 square kilometers (38,610 square miles) of farmland. Earlier in May, however, a huge dust storm from Mongolia and China's Inner Mongolia Autonomous Region blew into Beijing, turning the sky yellow and pushing air quality readings to 500 micrograms per cubic metre, well above WHO's limit of 25 micrograms.

The temperature in Inner Mongolia has been 1 to 2 degrees Celsius higher this spring than the average in prior years, increasing fire risk in a region already dry. Fire broke out in the Greater Hinggan Mountains in early May and spread to 10,000 acres. For three days 5,000 or more fire-fighters battled the forest fire, which was ignited by illegal dumping of burning residue.

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

Several large areas in the May through July map draw attention to changing water conditions in China. The vast, predominately white area in the Southeast indicates a return to near-normal conditions, a significant change from surpluses observed in prior months. A large block of exceptional deficit – shown in dark red – is forecast just south of Mongolia in western Inner Mongolia, China. Underlying purple tones indicate both deficits and surpluses as the region transitions to deficit. In a vast region to the south, moderate to severe surpluses are forecast to emerge in Qinghai. And, severe to exceptional surpluses are forecast in a wide north/south swatch of central Tibet.

Elsewhere, moderate to severe deficits are forecast in much of Mongolia and in the Tarim Basin of Xinjiang, China southwest of Mongolia, with both deficits and surpluses in some areas. Moderate to severe deficits are also forecast scattered throughout northern Japan. In southern China moderate deficits are expected to emerge in coastal Guangdong and in Yunnan.

The forecast for August through October shows a significant retreat of water anomalies in China’s eastern half, with some moderate deficits in Guizhou, Sichuan, and coastal Guangdong. The extent of deficits in Mongolia and western Inner Mongolia is forecast to diminish, as is the extent of water anomalies, both deficits and surpluses, in western China. Moderate to severe deficits are forecast to emerge in North Korea and in Hokkaido, Japan.

The forecast for the final months – November through January – indicates the emergence of widespread deficits of varying severity in the region.

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