China's research vessel and icebreaker Xuelong (or Snow Dragon), rescued 52 passengers stranded aboard the Russian ship Akademik Shokalskiy vessel in Antarctica on January 2, 2014. However, due to the dramatic change of weather conditions on January 3, Xuelong was stuck itself by thick floes of ice.

Taking advantage of spaceborne Synthetic Aperture Radar (SAR)’s capability on Earth Observation, a research team led by Prof.Dr. Li Xiaoming from the CAS Key Laboratory of Digital Earth Science at RADI provided satellite observation data in time and detailed scientific interpretation for the successful rescue campaign of the Chinese icebreaker.

The research team obtained five scenes of high-resolution TerraSAR-X data acquired  during January 1 to 6 at the area where Xuelong was beset.

Prof.Li was invited on January 7 to attend a consulting meeting organized by the State Oceanic Administration (SOA) to help Xuelong solve its difficulties. Based on his analysis of the SAR data, Prof. Li made a suggestion on the route by which Xuelong could manoeuvre through the heavy ice.Thanks to the 13-hour-long remorseless efforts, the Chinese icebreaker was succeeded in entering an area of clear water and finally released itself.

Prof. Li joined RADI on January 2014. LI received his Ph.D. degree from the University of Hamburger in 2010. Before he joined RADI, Prof. Li had been studied and worked in the German Aerospace Center (DLR) for more than 7 years focusing on the research of SAR observations of oceanic dynamics in multi-scale.

The upper: The ScanSAR（？DLR）data was acquired at the water area where Xuelong was stuck (spatial resolution: 18 meters; swath width:100 kilometers) at 17:52 on January 5, 2014 (Beijing Time) from the German TerraSAR-X satellite.

The lower: an enlargement of the red region of the upper image. The bright spot in the black circle is Xuelong. The image clearly shows that Xuelong is trapped itself by thick floes of ice. To its east, there is a clear water area and a mixture of thin ice. The ice breaking’s capacity of Xuelong is over 1 meter while the thickness of the thin ice area is less than 0.5 meters according to the analysis.