Chinese surnames are used by Han Chinese and Sinicized ethnic groups in Mainland China, Hong Kong, Macau, Malaysia, Taiwan, Korea, Singapore, Vietnam and among overseas Chinese communities. In ancient times two types of surnames existed, namely xing (Chinese: å§; pinyin: xÃ¬ng) or lineage names, and shi (Chinese: æ°; pinyin: shÃ¬) or clan names.
An ice sheet is a large permanent layer of ice covering a continental shelf, defined as having an extent greater than 50,000 km2 (19,305 mi2). An ice sheet is larger than a glacier or ice shelf.
The floating sea-ice cover of the polar regions. Driven by winds and ocean currents, pack ice is a mixture of ice fragments of varying size and age that are squeezed together and cover the sea surface with little or no open water. At maximum expansion during the winter, pack ice covers about five percent of Arctic waters and about eight percent of Antarctic waters.