Scientists who just returned from the country's 32nd Antarctic expedition say they have discovered the biggest canyon on earth during polar research. They say it's twice as big as the Grand Canyon in the United States.

More than 100 researchers aboard Xue Long arrived in Shanghai this morning on Tuesday morning, receiving a warm welcome from their families and local officials. They returned after a 158-day trip to Antarctica that began in November. They completed 45 scientific research projects in the polar region, including the discovery of a super canyon underneath the ice.

"We think the world's biggest canyon is hidden under the ice cap of Antarctica. It's about 1,100 kilometers long -- twice the length of Colorado Canyon. The depth is similar, too, at around one kilometer," said Sun Bing, deputy Voyage Leader of 32nd Antarctic Research Expedition.

The discovery was made by scientists on the polar airplane "Xue Ying 601", which is used to transport goods, handle emergency rescues and conduct scientific research. China was the fifth country to use a plane in polar research after the US, Russia, Germany and Australia.

"The plane is equipped with a gravimeter, magnetometer and ice radar and other scientific tools, which were all used in Antarctica for the first time. The aircraft has many technical requirements since it has to cope with the snow and low temperatures. It's also equipped with sled-like landing gear," said Li GUO, deputy Voyage Leader of 32nd Antarctic Research Expedition.

During the expedition, the plane covered a total area of 850,000 square kilometers around Zhongshan Station, mainly in the east part of Antarctica. It also helped scientists find more than 30 sub-glacial lakes and collect other valuable data. With this plane, scientists are now discussing the possibility of sending research teams to Antarctica by aircraft in the future. It would reduce travel time to dozens of hours compared to 20 days for Xue Long.

"A number of countries need to be involved in the aviation system to the polar region. So there is an aviation network in the east Antarctic region, with many countries sharing resources. We hope we can be part of the network and use our own aircraft to send us to Antarctica," Li said.

Xue Long is China's only icebreaking vessel and was launched in the 1990s. Another icebreaking vessel will be built and bidding for the contract will begin by the end of this month. The budget is estimated at one billion yuan. It will likely to be completed within two years and largely boost the country's polar research capacity.