The photographs actually show sand dunes coated with a thin layer of frozen carbon dioxide, or dry ice, less than 240 miles from the planet's north pole.
这张图片实际显示的，是距离火星北极不足240英里的沙丘上覆盖的一层薄薄的冰冻二氧化碳、或干冰。
2
The white material at the top of the cliff, near the planet's North Pole, is carbon dioxide ice.
照片上显示的悬崖上的白色物质是位于火星北极地区的干冰。
3
A warmer pole means higher sea levels and a thaw in the arctic permafrost would lead to even more methane and carbon dioxide being released into the atmosphere.