Scientists said Tuesday they have confirmed the existence of ice on the Moon's surface for the first time.

科学家周二表示，他们已首次确定月球表面有冰存在。

Signs of ice on the Moon have been reported by scientists for years, but previous observations could have been explained by other phenomena, such as unusually reflective lunar soil, the study authors said.

"This is the first time scientists have definitive evidence for the presence of water ice on the surface," lead author Shuai Li of the Hawaii Institute of Geophysics and Planetology told AFP.

The ice mainly lies in the frigid shadows of craters at the lunar poles, and was detected using instruments that flew on the Chandrayaan-1 spacecraft, launched in 2008 by the Indian Space Research Organization.

Using data from NASA's Moon Mineralogy Mapper (M3) instrument, researchers identified three chemical signatures "that definitively prove there is water ice at the surface of the Moon," said a NASA statement. 

The polar regions where the ice lies are "super cold," Li said, noting that the  warmest temperatures never reach above minus 250 degrees Fahrenheit (-157 Celsius.

It is unclear exactly how much ice exists on the surface, since the instruments could only detect ice within a few millimeters of the Moon's surface, he said.