Sea Ice

When you think about the polar regions of Earth, images like this likely come to mind. You have learned that at the polar regions, the temperature of the ocean water varies less with depth than it does in other areas. In the polar regions, the surface water is almost as cold as the deep water, and sometimes the temperature is so low that solid ice forms. Sea ice is common in the polar regions and it plays an important role in Earth’s solar radiation balance because it reflects large amounts of sunlight back to space.

What is the relationship between sea ice and atmospheric motion?

Sea ice reflects large amounts of sunlight away from Earth’s poles. This contributes to the imbalance in net solar radiation between the poles and the equatorial region. This imbalance of solar radiation is what drives atmospheric motion.

At any given time, sea ice covers about 15 percent of Earth’s surface. However, the extent of global sea ice is shrinking due to the global warming you learned about in the previous section. It also varies by season—with the winter time obviously having more ice cover than the summer.