China’s largest freshwater lake drained by prolonged heat and drought.
Between the winter and summer seasons, Poyang Lake, in China’s Jiangxi Province, routinely fluctuates in size. In winter, water levels on the lake are usually low. Then, summer rains cause the country’s largest freshwater lake to swell as water flows in from the Yangtze River.
However, the lake has not swelled in the summer of 2022. In fact, a prolonged heat wave and drought across much of the Yangtze River Basin has dried the lake out early and pushed water levels to lows not seen in decades.
The Operational Land Imager (OLI) on Landsat 8 acquired these pairs of images on July 10, 2022 (upper image above, left image below), and August 27, 2022 (lower image above, right image below). The images are composites that combine OLI observations of shortwave infrared, near-infrared, and visible light.
Poyang Lake’s highest water levels of the year occurred on June 23 (as measured at the Xingzi Station). After that, high temperatures and a lack of rain caused water levels in the lake to drop rapidly, according to the Jiangxi Hydrological Monitoring Center. By August 6, water levels had fallen to 11.99 meters (39.33 feet), marking what the center called the start of the lake’s “dry season.” That low came approximately 100 days earlier than usual. It was the earliest date that the water level dropped to such a low mark since records were first kept in 1951. Water levels have continued to drop, registering just 8.96 meters (29.4 feet) on August 30.
The emptying of Poyang Lake has disrupted irrigation, shipping, and drinking water systems for nearby communities. Additionally, millions of people living throughout the Yangtze River watershed are being affected as extreme heat and drought put pressure on China’s water supplies, farming, electricity generation, and industrial activity.
NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey.