SHANGHAI, Aug 15 (Reuters) - Regions that rely on the Yangtze, China's longest river, are having to deploy pumps and cloud-seeding rockets as a long drought depletes water levels and threatens crops, and a heatwave is set to last another two weeks.
The Yangtze's middle and lower reaches have faced temperatures in excess of 40 Celsius (104 Fahrenheit) over the past month, with experts blaming climate change-induced variations in the western Pacific subtropical high, a major determinant of summer weather throughout east Asia.
With the autumn harvest under threat, the agriculture ministry has deployed 25 teams to key regions to take action to protect crops, the Shanghai government's Guangming Daily newspaper reported.
The heatwave is likely to last for another two weeks, making it the longest sustained period of extreme temperatures since records began in 1961, experts with China's National Climate Center told the official Science and Technology Daily on Monday.
Rainfall in the Yangtze river drainage area fell about 30% in July and is 60% lower than normal in August, with the river's tributaries "significantly lower" than historical levels, according to the Yangtze River Water Resources Commission.
The Poyang lake in central China's Jiangxi province, which plays a major role in regulating Yangtze water flows in the summer, has shrunk to levels normally seen during the winter dry season after a 50% decline in rain in July.
Villages relying on water from the lake have been forced to deploy pumps to irrigate rice fields, media reported.
In the sprawling southwestern municipality of Chongqing, facing its second hottest summer since records began in 1961, 900 missiles have been made available to try to "seed" clouds and induce rain, media reported.
Other regions have launched their own weather modification operations.
China normally releases water from the Three Gorges reservoir to relieve drought on the Yangtze but downstream outflows are half the level of a year earlier, official data showed.
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