China’s longest river shorter than believed

BEIJING (AFP) – Scientists have found that China’s longest river, the Yangtze, is nearly 90 kilometers shorter than previously thought, state media said recently.

A new measurement of the river using satellite technology found that it stretches for 6,211.3 kilometers, shorter than the accepted length of 6,300 kilometers, the official Xinhua news agency said.

But it is still the longest river in China and the third longest river in the world, according to Xinhua.

“It does not mean the river is shortened,” said Liu Shaochuang, a researcher with the Institute of Remote Sensing Application under the Chinese Academy of Sciences, Xinhua reported.

“This is the result of the improvement of measuring techniques and different starting and ending points,” he said.

The new data has to be examined by the State Bureau of Surveying and Mapping before it can become official national geographic data.

Liu, who headed the survey, said the satellite remote sensing technology used to remeasure the river was far more accurate than the previous measuring method that relied on topographic maps.

Researchers measured the river in downstream and upstream directions three separate times using nearly 40 images taken by a US satellite.

The data was then calculated by computer.

The widely-accepted length of the Yangtze River comes from a survey conducted more than 20 years ago, Xinhua said.

The measurement from the 1970s showed that the Yangtze is longer than the Mississippi River in the United States, it said.

However, the Time Almanac for 2001 lists the Mississippi’s length as 5,970 kilometers while the Yangtze’s length is listed as only 5,797 kilometers.

The longest river in the world is the Nile River in Africa followed by the Amazon River in South America.