China plans to increase its presence in Antarctica with two more research stations, an official in charge of the country's scientific programs in the polar regions said on Tuesday.

The two new facilities are expected to join the existing three Chinese stations on Antarctica — Changcheng (Great Wall), Zhongshan, and Kunlun — by 2015, said Xu Shijie, an official with the China Arctic and Antarctic Administration.

Tang Jingdong, a member of the expedition team sent to Antarctica, kisses his daughter upon his return in Shanghai on Tuesday. Pei Xin / Xinhua

He unveiled the plan the day that the Chinese research vessel Xuelong (Snow Dragon) returned from its 29th expedition to the South Pole and anchored at a Shanghai port.

The five-month expedition completed missions that include selecting the site for one of the new facilities, he said.

The new summer station will be built on Princess Elizabeth Land, which is on the east side of the continent. The site is 520 km from Zhongshan Station, another of China's research facilities.

"China has had a considerable advantage in the eastern part of Antarctica, and the new station will optimize the layout and strengthen our future development," Xu said.

The new facility, which will be started in the second half of this year and completed next year, will provide support for the operations of inland station Kunlun, and facilitate China's expedition on the Grove Mountains, which consists of glacier mapping and studies on climate change, he said.

The expedition team also made an eight-day exploration on Victoria Land, to select a site for another station, he added.

Xuelong set out from Guangzhou, Guangdong province, with 239 people on board on Nov 5. The expedition took 156 days, covering more than 29,000 nautical miles.

The ship sailed to a position 75 degrees south, farther south than it ever had before. This signified Xuelong's new breakthrough in ice-breaking capability, said Sun Bo, deputy leader of the 29th expedition team.

One of the accomplishments for the 29th expedition is the ice drill from Dome A, the highest ice feature in Antarctica, Sun told the media on Xuelong on Tuesday.

Three tubes of ice, 8.3 meters long altogether, were drilled from more than 130 meters under the ice cap.

Scientists from China, who have worked on the project for years, acquired the longest piece from the core of Antarctica the South Pole, which is a major breakthrough, Sun said.

The ice will provide valuable information concerning climate change in the area over thousands of years, he said.

Meanwhile, a system to observe water flow under the ice cap was put in use during the expedition this year, he said.

Developed solely by Chinese, the system has produced 3-D radar images that proved ice caps grow rapidly from the bottom. The observation disproved previous theories that ice caps are formed from above, he said. "It's an amazing phenomenon, water deep under the ice running rapidly upward, from a lower to higher point," he said.

Changes in the sea level have significant consequence to the climate but scientists know little about what causes the changes, he said. The new observation has provided information for the study of ice caps and sea level changes, he added.

Because the Antarctic is a great place for astronomical observations, China has built a large optical telescope there, and obtained its first data from it this year.

This will provide valuable information in the studies of supernovas and cosmology, Sun said.

China also plans to build another polar expedition vessel. It will be designed jointly by Chinese and Finnish companies and be built in China. The new ship will launch in 2014, according to the China Arctic and Antarctic Administration.