Using the satellite remote sensing technology, scientists from the Institute of Remote Sensing and Digital Earth (RADI), CAS, have recently pinpointed the source of the Yalong River and re-measured the length of the river.

The Yalong River is the longest branch of the Yangtze River. Most of the existing literature believes that the Yalong River originates from the southern foot of Bayan Har Mountains in Qinghai province, and that its length is between 1500 kilometers and 1637 kilometers.

According to LIU Shaochuang, a leading scientist in the research project, the source of the Yalong River has been finally determined to be located at the southern foot of Bayan Har Mountains in Chindu County, Yushu Tibetan Autonomous Prefecture, Qinghai province. The source has a sea-level elevation of 4870 meters, and the top stream is called Nongqiongqu. The full length of the Yalong River is 1670 kilometers. In addition, the project team has re-measured the drainage area of the Yalong River which is 86405 square kilometers.

To locate the headstreams of the river and measure its length, LIU's team used remote sensing technology, combining with field verification at the source area. The source determination of the river is based on the principle of "farthest source orientation" which is generally accepted in the geographical circles.

LIU has worked to locate the sources of the world's largest rivers since the 1990s. He has pinpointed the sources of 17 principal rivers and measured their lengths by using satellite remote-sensing technology and conducting field investigations.